JP2022031491A - Inorganic fiber molded body containing binder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, as a main object, an inorganic fiber molded body containing a binder which has small frictional force and high shear force and surface pressure on the whole surface.

SOLUTION: An inorganic fiber molded body containing a binder is constituted by having a first surface and a second surface which are opposed to each other and containing a binder in an organic fiber molded body in which a plurality of recesses are formed. The inorganic fiber molded body containing the binder has a plurality of high concentration binder regions having relatively high binder concentration and a low concentration binder region having relatively low binder concentration other than the high concentration binder regions. The plurality of high concentration binder regions extend in a direction crossing the first surface and the second surface and are scattered on at least the first surface. A volume ratio of the low concentration binder region to the plurality of high concentration binder regions is 1.5 or more and 6.0 or less.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a binder-containing inorganic fiber molded body in which a binder is contained in the inorganic fiber molded body.

Inorganic fiber molded bodies made of inorganic fibers typified by ceramic fibers in the form of mats are used for applications exposed to high temperature conditions such as industrial heat insulating materials, refractory materials, and packing materials. In recent years, the inorganic fiber molded body has been used as a cushioning material (seal member) for an automobile exhaust gas purification device, that is, an exhaust gas treatment body when an exhaust gas treatment body such as a catalyst carrier or a particle filter is housed in a metal casing. It is also used as a holding material for an exhaust gas purification device, which is wound around the exhaust gas and interposed between the exhaust gas treatment body and the casing (Patent Document 1).

The wound body in which the holding material for the exhaust gas purification device is wound around the exhaust gas treatment body is housed in the casing by a known method such as a press-fitting method (stuffing method), a sizing method (swazing method), or a clamshell method. However, when the material is housed in the casing, the holding material in the wound body may be delaminated due to the frictional force generated between the wound body and the casing. Above all, when the press-fitting method is used, the wound body is press-fitted into the casing, so that the above-mentioned problems tend to occur easily in the holding material.

In order to prevent the occurrence of such a defect, it has been conventionally known to perform a needling treatment on an inorganic fiber molded product. The needling treatment is a treatment in which a fiber entanglement means such as a needle is inserted and removed in a crossing direction with two opposing surfaces of an inorganic fiber molded body, and several to several tens of inorganic fibers are inserted and removed in the crossing direction by the above treatment. Needle marks are formed by forming a bundle of inorganic fibers that are oriented in the (longitudinal direction) and entangled three-dimensionally. In the inorganic fiber molded body, the formation of such needle marks increases the shearing force and makes delamination less likely to occur.

However, in the needling treated inorganic fiber molded body, if the number of needle marks is small, it is difficult to obtain the desired shearing force, while if the number of needle marks is too large, the repulsive force (elasticity) decreases. Therefore, when it is used as a holding material for an exhaust gas purification device, there is a problem that it becomes difficult to obtain the holding property of the exhaust gas treated body after the casing is housed.

Therefore, in order to obtain a high shearing force while suppressing a decrease in the repulsive force, the inorganic fiber molded body is subjected to a needling treatment, and a binder is contained so as to have a uniform concentration over the entire inorganic fiber molded body. A technique for binding inorganic fibers with a binder is used. According to this technique, since the entangled points of the inorganic fibers are bound by the binder in the inorganic fiber molding body, high shearing force can be exhibited even if the number of needle marks is reduced. Further, since the entangled points between the inorganic fibers are bound by a binder in a state where the inorganic fibers are randomly oriented, it is possible to suppress a decrease in the repulsive force while having a high shearing force. The binder-containing inorganic fiber molded product is referred to as a binder-containing inorganic fiber molded product.

Japanese Unexamined Patent Publication No. 2007-162583

However, in the binder-containing inorganic fiber molded body having needle marks, if the binder concentration is increased, the shearing force can be improved, but the frictional force on the entire surface of the inorganic fiber molded body increases as the binder content increases. Therefore, for example, when used as a holding material for an exhaust gas purifying device, the frictional force generated between the casing and the casing may increase and the canning property may be inferior. Further, depending on the magnitude relationship between the frictional force generated between the casing and the shearing force of the binder-containing inorganic fiber molded body, delamination is likely to occur in the binder-containing inorganic fiber molded body when press-fitted into the casing. There is. Further, when the binder-containing inorganic fiber molded body has a high binder concentration, the surface pressure becomes small, and when used as a holding material for an exhaust gas purifying device, the holding property of the exhaust gas treated body after being housed in the casing may not be sufficiently obtained. be.

On the other hand, in the binder-containing inorganic fiber molded body, when the binder concentration is lowered, the frictional force on the entire surface becomes small and the surface pressure becomes large, but the shearing force becomes low as the number of binding points between the inorganic fibers decreases. Delamination is likely to occur. Therefore, for example, when used as a holding material for an exhaust gas purification device, even if the frictional force generated between the casing and the casing is small, the binder-containing inorganic fiber molded body may easily undergo delamination due to the frictional force. ..

In Patent Document 1, regarding the sealing member for the catalytic converter, an organic binder or a needle is used for at least one end of the upstream end and the downstream end in the exhaust gas flow direction as compared with the other regions. It is disclosed that the degree of reinforcement is increased by the punching process. In Patent Document 1, by adopting the above-mentioned structure of the seal member, the elasticity of the seal member is maintained in the above-mentioned other regions while avoiding the deviation caused by the insertion resistance or the like at the end portion when the seal member is inserted into the casing. The repulsive force makes it possible to maintain a high holding force of the sealing member. However, in the structure disclosed in Patent Document 1, it is presumed that it is difficult to achieve both reduction of surface frictional force and improvement of shearing force and surface pressure on the entire surface of the sealing member.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a binder-containing inorganic fiber molded body having a small frictional force on the entire surface and a high shearing force and surface pressure.

The present invention is a binder-containing inorganic fiber molded body having a first surface and a second surface facing each other and having a binder contained in an inorganic fiber molded body in which a plurality of recesses are formed, wherein the binder-containing inorganic fiber is contained. The fiber molded body has a plurality of high-concentration binder regions having a relatively high binder concentration and a low-concentration binder region having a relatively low binder concentration other than the high-concentration binder region, and the plurality of high-concentration binders. The regions extend in the direction intersecting the first surface and the second surface, and are scattered at least in the first surface, and the volume ratio of the low concentration binder region to the plurality of high concentration binder regions is Provided is a binder-containing inorganic fiber molded body, characterized in that it is 1.5 or more and 6.0 or less.

According to the present invention, the binder-containing inorganic fiber molded product has two regions having different binder concentrations, and the low-concentration binder region occupies a larger volume ratio than the plurality of high-concentration binder regions among the above two regions. The frictional force on the entire surface of the surface can be reduced and the surface pressure can be increased. On the other hand, in the high-concentration binder region, the inorganic fibers and the bundles of inorganic fibers are firmly bound by the binder. By extending such a high-concentration binder region in a direction intersecting the first surface and the second surface, the high-concentration binder region exists in a columnar shape in the inorganic fiber molding body, and Since the columnar high-concentration binder regions are scattered, a high shearing force can be obtained in the entire binder-containing inorganic fiber molded body. As a result, the binder-containing inorganic fiber molded product of the present invention is less likely to undergo delamination, and can have good canning property when used as a holding material for an exhaust gas purification device, for example.

In the present invention, it is preferable that the binder concentration in the high-concentration binder region is more than 5% and 25% or less, and the binder concentration in the low-concentration binder region is 0% or more and 5% or less. It is possible to strike a good balance between the effect of reducing the frictional force and the effect of improving the surface pressure on the entire surface of the binder-containing inorganic fiber molded product by the low-concentration binder region and the effect of improving the shearing force by the plurality of high-concentration binder regions. Because it can be done.

In the present invention, it is preferable that the recess is a needle mark. In the needle mark, a plurality of inorganic fibers are oriented in the vertical direction to form an inorganic fiber bundle that is three-dimensionally entangled, and the inorganic fiber is restrained in the inorganic fiber bundle, so that it may have a higher shearing force. Because it can be done.

In the present invention, it is preferable that the recess is located in at least a part of the plurality of high-concentration binder regions. This is because it is easy to apply the binder liquid to the concave portion, and by applying the binder liquid to the concave portion, it is presumed that the binder adhering region in contact with the casing can be reduced, and as a result, the friction can be reduced. Further, when the recess is a needle mark, the binder liquid easily permeates the inorganic fiber bundle forming the needle mark, and the high-concentration binder region can be easily scattered and arranged according to the position of the needle mark. Is. Further, in the above case, since the binder is present in the inorganic fiber bundle in the needle mark at a high concentration, the peripheral fibers of the needle mark and the inorganic fiber bundle are firmly bound by the binder, so that the shearing force is higher. This is because it is presumed that it is possible.

In the present invention, it is preferable that the binder contains an organic binder. This is because the organic binder can be easily impregnated into the inorganic fiber molded body and can exert a sufficient thickness binding force, so that the binder-containing inorganic fiber molded body can be made flexible and has excellent strength. .. In addition, the organic binder can be easily thermally decomposed or burned under the operating temperature conditions of the binder-containing inorganic fiber molded product of the present invention.

In the present invention, it is possible to obtain a binder-containing inorganic fiber molded body having a small frictional force on the entire surface and a high shearing force and surface pressure.

It is a schematic plan view which shows an example of the binder-containing inorganic fiber molded article of this invention. It is a schematic sectional drawing which shows an example of the binder-containing inorganic fiber molded article of this invention. It is a schematic sectional drawing which shows an example of the binder-containing inorganic fiber molded article of this invention. It is a schematic plan view which shows the other example of the binder-containing inorganic fiber molded article of this invention. It is a schematic sectional drawing which shows the other example of the binder-containing inorganic fiber molded article of this invention. It is a schematic sectional drawing which shows the other example of the binder-containing inorganic fiber molded article of this invention. It is explanatory drawing which shows the arrangement mode of the high-concentration binder region in a gathering part. It is explanatory drawing which shows the arrangement mode of the high-concentration binder region in a gathering part. It is a schematic diagram which shows the shape of a needle mark. It is explanatory drawing which shows the measuring method of the diameter of a needle mark. It is a schematic plan view of the binder-containing inorganic fiber molded article of Examples 1 and 2. It is a schematic side view which shows the measuring device of a friction force.

Hereinafter, the binder-containing inorganic fiber molded product of the present invention will be described in detail. The binder-containing inorganic fiber molded body of the present invention has a first surface and a second surface facing each other, and the binder is contained in the inorganic fiber molded body in which a plurality of recesses are formed. The binder-containing inorganic fiber molded body has a plurality of high-concentration binder regions having a relatively high binder concentration and a low-concentration binder region other than the high-concentration binder region having a relatively low binder concentration. The high-concentration binder region of the above extends in a direction intersecting the first surface and the second surface, and is scattered at least on the first surface, and the low-concentration binder region with respect to the plurality of high-concentration binder regions. The volume ratio of is within a predetermined range.

1 is a schematic plan view showing an example of a binder-containing inorganic fiber molded product of the present invention, and FIGS. 2 and 3 are a sectional view taken along line X1-X1 and a sectional view taken along line Y1-Y1 of FIG. 1, respectively. The binder-containing inorganic fiber molded body 10 exemplified in FIGS. 1 to 3 has an opposed first surface 10a and a second surface 10b, and is an inorganic fiber molded body in which a plurality of needle marks which are through holes are formed as recesses 2. 1 contains a binder. The binder-containing inorganic fiber molded body 10 includes a plurality of high-concentration binder regions A having a relatively high binder concentration and a low-concentration binder region B having a relatively low binder concentration, which is a region other than the high-concentration binder region A. Have. The plurality of high-concentration binder regions A extend in the direction intersecting the first surface 10a and the second surface 10b (Z direction in FIGS. 2 and 3), and are scattered at least on the first surface 10a. .. In FIGS. 1 to 3, a plurality of high-concentration binder regions A are scattered on the first surface 10a and the second surface 10b. Further, in the binder-containing inorganic fiber molded body 10, the volume ratio of the low-concentration binder region B to the plurality of high-concentration binder regions A is within a predetermined range. In FIGS. 1 to 3, the recess (needle mark) 2 is located in 100% of the high-concentration binder region A. That is, the recesses (needle marks) 2 are located in all the high-concentration binder regions A.

FIG. 4 is a schematic plan view showing another example of the binder-containing inorganic fiber molded product of the present invention, and FIGS. 5 and 6 are a sectional view taken along line X2-X2 and a sectional view taken along line Y2-Y2 of FIG. 4, respectively. be.
4 to 6 show an example in which a plurality of needle marks that are non-penetrating holes are formed as the recesses 2, and the recesses (needle marks) 2 are located in 50% of the high-concentration binder region A. There is.

According to the binder-containing inorganic fiber molded body of the present invention, the binder-containing inorganic fiber molded body has two regions having different binder concentrations, and the low-concentration binder region occupies a larger volume ratio than the plurality of high-concentration binder regions among the above two regions. , The frictional force can be reduced on the entire surface of the binder-containing inorganic fiber molded body. Specifically, in the low-concentration binder region, the surface frictional force is small because the binder content is low, but in the high-concentration binder region, the surface frictional force is large because the binder content is high. According to the binder-containing inorganic fiber molded body of the present invention, a high-concentration binder region having a large surface frictional force exists on a part of the surface, but the low-concentration binder region occupies a large proportion in the binder-containing inorganic fiber molded body, and Since the high-concentration binder regions are scattered, the level of the surface frictional force is made uniform over the entire surface, and as a result, the frictional force on the entire surface of the binder-containing inorganic fiber molded body can be reduced.
Further, according to the binder-containing inorganic fiber molded body of the present invention, since the volume ratio occupied by the low-concentration binder region is larger than that of the plurality of high-concentration binder regions, the surface pressure is increased on the entire surface of the binder-containing inorganic fiber molded body. be able to.
Further, according to the binder-containing inorganic fiber molded body of the present invention, the inorganic fibers and the bundles of inorganic fibers are firmly bound by the binder in the high-concentration binder region. By extending such a high-concentration binder region in a direction intersecting the first surface and the second surface, the high-concentration binder region exists in a columnar shape in the inorganic fiber molding body, and Since the columnar high-concentration binder regions are scattered, a high shearing force can be obtained in the entire binder-containing inorganic fiber molded body.
As described above, the binder-containing inorganic fiber molded product of the present invention has a small frictional force on the entire surface and a high shearing force and surface pressure, so that delamination is less likely to occur, and is used, for example, as a holding material for an exhaust gas purification device. The canning property of the case can be improved.

In the present invention, a plurality of high-concentration binder regions are scattered on at least the first surface of the binder-containing inorganic fiber molded product. That is, in the binder-containing inorganic fiber molded body of the present invention, a plurality of high-concentration binder regions are scattered in the in-plane direction of at least the first surface of the inorganic fiber molded body.

"Scattered on the first surface" means that the plurality of high-concentration binder regions are individually scattered on the first surface of the binder-containing inorganic fiber molded body at desired intervals. , When the reference region R is set on the first surface, a plurality of high-concentration binder regions are included in a predetermined number range in the reference region R at any position on the surface on which the reference region R is set. Here, the reference area R is a virtually defined area, and is a 5 cm square. For example, even if the reference region R shown in FIGS. 1 and 4 is moved from the in-plane position of the first surface 10a of the binder-containing inorganic fiber molded body 10 shown in FIGS. 1 and 4, the reference region R is moved in all directions. A plurality of high-concentration binder regions are included in R in a predetermined number range. The reference region R can be set at a desired position on the first surface of the binder-containing inorganic fiber molded product.

Here, the fact that a plurality of high-concentration binder regions are "scattered on the first surface" means that, specifically, when the reference region R is set on the first surface of the binder-containing inorganic fiber molded product, the reference region R is set. It means that the number of high-concentration binder regions contained is a predetermined number, specifically, 12 or more and 125 or less. Above all, the number of high-concentration binder regions contained in the reference region R (5 cm × 5 cm = 25 cm ² ) is preferably 20 or more and 100 or less, and particularly preferably 25 or more and 75 or less. When a part of one high-concentration binder region is included in the reference region, if 50% or more of the planar view area of the high-concentration binder region is included in the reference region R, it can be counted as one. can. The number of high-concentration binder regions contained in the reference region R can be counted by any method, and the method is not particularly limited. For example, if the binder contained in the binder-containing inorganic fiber molded body is an organic binder, the binder-containing inorganic fiber molded body is heated at about 400 ° C. for 60 seconds in an electric furnace to discolor the organic binder, and then a 5 cm square sample is prepared. The number of black discolored portions expressed on the first surface of the sample by cutting out can be used as the number of high-concentration binder regions contained in the reference region R. It indicates that the discolored portion is a high-concentration binder region, and the non-discolored portion is a low-concentration binder region. The plan view means that the binder-containing inorganic fiber molded body is viewed from the first surface side.

The ratio of the total area of the plurality of high-concentration binder regions occupying the reference region R on the first surface is not particularly limited as long as the number of high-concentration binder regions contained in the reference region R is within the above-mentioned predetermined number range. For example, it is preferably 10% or more and 50% or less, and more preferably 20% or more and 40% or less.

Hereinafter, the binder-containing inorganic fiber molded product of the present invention will be described for each configuration.

1. 1. High-concentration binder region and low-concentration binder region The high-concentration binder region in the present invention is a region in which the binder concentration is relatively high, and is in the direction of intersecting the first surface and the second surface of the binder-containing inorganic fiber molded body. It is extending and scattered on at least the first surface of the binder-containing inorganic fiber molded body. Further, the low-concentration binder region is a region other than the high-concentration binder region where the binder concentration is relatively low.

In the present invention, since the high-concentration binder regions are scattered, the high-concentration binder region and the low-concentration binder region are island regions in which a plurality of high-concentration binder regions are formed on at least the first surface of the binder-containing inorganic fiber molded body. , The low-concentration binder region can be used as a sea region and can exist in the shape of a sea island.

The binder concentration refers to the ratio of the mass of the binder to the mass of the inorganic fiber, and if the binder concentration is in the high-concentration binder region, the high-concentration binder per mass of the inorganic fiber contained in the high-concentration binder region. The ratio (%) of the mass of the binder contained in the region.

In the binder-containing inorganic fiber molded product of the present invention, the volume of the low-concentration binder region is larger than the volume of the plurality of high-concentration binder regions. As a result, the low-concentration binder region having a low surface frictional force occupies a large proportion on the surface of the binder-containing inorganic fiber molded product, so that the frictional force is reduced and the surface pressure is increased on the entire surface of the binder-containing inorganic fiber molded product. can do.

In the present invention, the volume ratio of the low-concentration binder region to the volume of the plurality of high-concentration binder regions may be 1.5 or more and 6.0 or less, and in particular, 1.7 or more and 5.0 or less. It is preferable, and it is particularly preferable that it is 2.0 or more and 4.0 or less. By setting the volume ratio within the above range, the frictional force on the entire surface of the binder-containing inorganic fiber molded body becomes smaller and the surface pressure becomes higher due to the low concentration binder region, while the binder due to the high concentration binder region. Since the shearing force of the entire contained inorganic fiber molded body is increased, both physical properties can be well balanced. If the volume ratio exceeds the above range, the ratio of the high-concentration binder region to the binder-containing inorganic fiber molded body is too small, and the effect of improving the shearing force by the high-concentration binder region may not be sufficiently obtained. be. On the other hand, if the volume ratio does not meet the above range, the proportion of the low-concentration binder region occupying the surface of the binder-containing inorganic fiber molded body becomes small, and the effect of reducing the frictional force on the entire surface and the surface of the low-concentration binder region are achieved. The pressure improving effect may not be sufficiently obtained.

The volume ratio of the low-concentration binder region to the plurality of high-concentration binder regions can be calculated by any method, and the method is not particularly limited. For example, the binder contained in the binder-containing inorganic fiber molded body may be an organic binder. For example, it can be calculated by the following procedure. That is, after the binder-containing inorganic fiber molded body is heated in an electric furnace at about 400 ° C. for 60 seconds to discolor the organic binder, a 5 cm square sample is cut out and a plurality of discolorations expressed on the first surface of the sample are cut out. For each portion, the area of the discolored portion is multiplied by the height of the discolored portion (that is, the height of the high-concentration binder region) in the vertical cross section in the thickness direction of the sample, and the height of the plurality of high-concentration binder regions contained in the sample is obtained. Calculate the total volume. Further, the volume of the low-concentration binder region is calculated by multiplying the area of the non-discolored portion by the thickness of the sample.
Then, the volume ratio can be calculated by dividing the volume of the low-concentration binder region by the sum of the volumes of the plurality of high-concentration binder regions.

Further, in the binder-containing inorganic fiber molded product of the present invention, the area ratio of the low-concentration binder region to the total area of the plurality of high-concentration binder regions is preferably 2 or more and 6 or less, and above all, 2 It is preferably 5 or more, and particularly preferably 2 or more and 4 or less. By setting the area ratio in the above range, the frictional force on the entire surface of the binder-containing inorganic fiber molded body can be reduced and the surface pressure can be increased by the low-concentration binder region, and the high-concentration binder region can be used. The shearing force of the entire binder-containing inorganic fiber molded body can be increased, and the physical properties of both can be well balanced.

The area ratio of the low-concentration binder region to the total area of the plurality of high-concentration binder regions can be calculated by any method, and the method is not particularly limited. For example, if the binder contained in the binder-containing inorganic fiber molded product is an organic binder, it can be calculated by the following procedure. That is, after the binder-containing inorganic fiber molded body is heated in an electric furnace at about 400 ° C. for 60 seconds to discolor the organic binder, a 5 cm square sample is cut out and a plurality of discolorations expressed on the first surface of the sample are cut out. The total area of the portions and the area of the non-discolored portion, which is a region other than the discolored portion on the first surface, are calculated. The area ratio can be calculated by dividing the area of the non-discolored portion by the sum of the areas of the plurality of discolored portions.

(1) High-concentration binder region The binder concentration in the high-concentration binder region may be higher than the binder concentration in the low-concentration binder region, and is preferably more than 5% and 25% or less, particularly 7% or more and 20%. It is preferably 9% or more, and particularly preferably 18% or less.
By setting the binder concentration of the high-concentration binder region within the above range, the binding force of the inorganic fibers and the inorganic fiber bundles can be enhanced in the high-concentration binder region, and the surrounding low concentration is passed through the high-concentration binder region. The binder regions are connected so that the binder-containing inorganic fiber molded body can have a high shearing force. Further, it is possible to strike a good balance between the effect of improving the shearing force by the plurality of high-concentration binder regions, the effect of reducing the surface frictional force by the low-concentration binder region, and the effect of improving the surface pressure. When the binder concentration in the high-concentration binder region exceeds the above range, the surface of the binder-containing inorganic fiber molded product becomes sticky due to the binder, and the effect of reducing the frictional force and the surface pressure on the entire surface of the binder-containing inorganic fiber molded product are obtained. It may be difficult to obtain the improvement effect of. Further, if it is an organic binder, problems such as difficulty in thermal decomposition, deterioration of the working environment due to the gas generated by thermal decomposition, and impaired cushioning are expected. On the other hand, if the binder concentration in the high-concentration binder region does not meet the above range, it may be difficult to obtain the effect of improving the shearing force by providing the high-concentration binder region.

The method for obtaining the binder concentration in the high-concentration binder region is not particularly limited, but for example, if the binder is an organic binder, it can be calculated by the following method. That is, the binder-containing inorganic fiber molded product is heated in an electric furnace at about 400 ° C. for 60 seconds to discolor the organic binder, and then a 5 cm square sample is cut out. Next, the discolored portion is cut out from the sample and the mass of the discolored portion (mass of the discolored portion before the binder burning treatment) is measured. Subsequently, the discolored portion is subjected to a binder burning treatment of heating at 800 ° C. for 1 hour, the organic binder in the discolored portion is burned down, and the mass of the discolored portion after the binder burnout treatment is measured. The mass of the discolored portion after the binder burnout treatment is defined as the mass of the inorganic fiber in the high-concentration binder region, and the mass difference before and after the binder burnout treatment is defined as the mass of the binder contained in the discolored portion. The binder concentration (%) per unit can be obtained.

The plan view shape of the high-concentration binder region is not particularly limited, and examples thereof include a perfect circle, a circle such as an ellipse, a quadrangle such as a square or a rectangle, a polygon, and a star shape. Of these, a circle is preferable, and a perfect circle is more preferable.

The diameter of the high-concentration binder region is not particularly limited, but can be, for example, 1.0 mm or more and 7.0 mm or less, particularly preferably 2.0 mm or more and 6.0 mm or less, and particularly 2.0 mm or more. It is preferably 5.0 mm or less. The diameter of the high-concentration binder region when the shape of the high-concentration binder region in the plan view is other than a perfect circle is the diameter equivalent to the circle of the area of the high-concentration binder region in the plan view. The diameter of the high-concentration binder region means the portion shown in φ1 in FIGS. 1 to 6.

Further, in a plan view, the area of the high-concentration binder region is not particularly limited, but can be, for example, 0.5 mm ² or more and 40.0 mm ² or less, and particularly 3.0 mm ² or more and 30.0 mm ² or less. In particular, it can be 3.0 mm ² or more and 25.0 mm ² or less.

When the diameter or area of the high-concentration binder region exceeds the above range, the high-concentration binder region having high frictional force and low surface pressure is locally present on the surface of the binder-containing inorganic fiber molded body, and the low-concentration binder is present. It may be difficult to obtain the effect of reducing the surface frictional force and the effect of improving the surface pressure depending on the region. On the other hand, if the diameter or area of the high-concentration binder region does not meet the above range, it may be difficult to form the high-concentration binder region, or the effect of improving the shearing force by the high-concentration binder region may not be sufficiently obtained. ..

The high-concentration binder region extends in a direction intersecting the first surface and the second surface of the binder-containing inorganic fiber molded product. As a result, the high-concentration binder region can exist in a columnar shape in the inorganic fiber molding body. The extending direction of the high-concentration binder region may be orthogonal to the first plane and the second plane, or may be oblique to each other. The higher the height of the high-concentration binder region is, the more preferable it is. It is preferable that the high-concentration binder region penetrates the binder-containing inorganic fiber molded body in the thickness direction. This is because the shearing force can be increased by setting the height of the high-concentration binder region with respect to the average thickness of the binder-containing inorganic fiber molded body within the above range.
If the height of the high-concentration binder region is smaller than the above range, the region in which the inorganic fiber or the bundle of inorganic fibers is not bound by the binder increases in the thickness direction of the binder-containing inorganic fiber molded body, so that the height is high. The effect of improving the shearing force by the concentration binder region may not be sufficiently obtained. The height of the high-concentration binder region is the average value of the lengths of the binder-containing inorganic fiber molded body in the direction orthogonal to the first surface and the second surface, regardless of the extending direction of the high-concentration binder region. It is the length indicated by H in FIGS. 2 to 3 and 5 to 6. The height of the high-concentration binder region is determined by heating the binder-containing inorganic fiber molded body in an electric furnace at about 400 ° C. for 60 seconds to discolor the organic binder, and then cutting out a sample to a desired size to obtain a vertical cross section of the sample. It can be specified from the height of the discolored portion expressed on the (cut surface).

The plurality of high-concentration binder regions are scattered on at least the first surface of the binder-containing inorganic fiber molded body. Among them, the high-concentration binder region penetrates the thickness direction of the binder-containing inorganic fiber molded body, and the first surface thereof. And it is preferable that they are scattered on both sides of the second surface. This is because the binder-containing inorganic fiber molded body can have a high shearing force by increasing the contact surface with the surrounding low-concentration binder region and connecting the surrounding low-concentration binder region via the high-concentration binder region. Is. It should be noted that the high-concentration binder region "scattered on the second surface" can be defined in the same manner as on the first surface.

In FIGS. 2 and 3, the high-concentration binder region A penetrates the binder-containing inorganic fiber molded body 10 in the thickness direction (Z direction) and is scattered on the first surface 10a and the second surface 10b of the binder-containing inorganic fiber molded body 10. Here is an example of what you are doing. Further, in FIGS. 5 and 6, the high-concentration binder region A does not penetrate the thickness direction (Z direction) of the binder-containing inorganic fiber molded body 10 and is scattered on the first surface 10a of the binder-containing inorganic fiber molded body 10. Here is an example.

As will be described later, the high-concentration binder region may be located in a recess that is a through hole or a non-penetration hole of the binder-containing inorganic fiber molded product, or may be located in a region other than the recess. As illustrated in FIGS. 2 and 3, the high-concentration binder region A located in the recess 2 which is a through hole penetrates the thickness direction (Z direction) of the binder-containing inorganic fiber molded body 10 and penetrates the first surface 10a and the first surface 10a. It may be scattered on both surfaces of the second surface 10b, and although not shown, it may be scattered only on the first surface 10a without penetrating the thickness direction (Z direction) of the binder-containing inorganic fiber molded body 10. Similarly, as illustrated in FIG. 5, the high-concentration binder region A located in the recess 2 which is a non-penetrating hole does not penetrate the thickness direction (Z direction) of the binder-containing inorganic fiber molded body 10 and is the first surface. It may be scattered only in 10a, and although not shown, it may be scattered in both the first surface 10a and the second surface 10b through the thickness direction (Z direction) of the binder-containing inorganic fiber molded body 10. .. Further, as illustrated in FIG. 6, the high-concentration binder region A located in the region other than the recess 2 does not penetrate the thickness direction (Z direction) of the binder-containing inorganic fiber molded body 10 and is formed only on the first surface 10a. Although not shown, they may be scattered on both sides of the first surface 10a and the second surface 10b through the thickness direction (Z direction) of the binder-containing inorganic fiber molded body.

The plurality of high-concentration binder regions may have the same or different spacing between two adjacent high-concentration binder regions. The average distance between two adjacent high-concentration binder regions is not particularly limited, but can be, for example, 3 mm or more and 10 mm or less, particularly preferably 4 mm or more and 9 mm or less, and particularly 5 mm or more and 9 mm or less. Is preferable. The distance between two adjacent high-concentration binder regions means, for example, the length of the portion indicated by d1 and d2 in FIGS. 1 and 4.

The plurality of high-concentration binder regions may be scattered with regularity or irregularly. For example, in FIGS. 1 and 4, a plurality of high-concentration binder regions A are regularly scattered. Specifically, in FIGS. 1 and 4, the high-concentration binder region A is the first direction in the planes of the first surface 10a and the second surface 10b of the binder-containing inorganic fiber molded body 10 (FIGS. 1 and 4). Is arranged at equal intervals d1 in the X direction), and is arranged at equal intervals d2 in the second direction (Y direction in FIGS. 1 and 4) orthogonal to the first direction. Has been done. In FIG. 1, the interval d1 and the interval d2 are the same, while in FIG. 4, the interval d1 and the interval d2 are different.

When the plurality of high-concentration binder regions are arranged at intervals d1 and interval d2 in the first direction and the second direction, the interval d1 and the interval d2 may be the same or different. good. Further, the interval d1 may be the same or different for each column in the first direction, and the interval d2 may be the same or different for each column in the second direction.

The number of high-concentration binder regions in the first direction and the second direction when the plurality of high-concentration binder regions are arranged at intervals d1 and d2 in the first direction and the second direction. Can be set as appropriate. The number of high-concentration binder regions may be the same or different for each column in the first direction or for each column in the second direction.

The plurality of high-concentration binder regions may form an aggregated portion. Here, the gathering portion means a region in which 15 or more high-concentration binder regions are contained in a region of at least 2.5 cm square, and it is preferable that 20 or more of them are contained. The upper limit of the number of high-concentration binder regions in the gathering portion is not particularly limited, but may be, for example, 30.

In the above gathering portion, a plurality of high-concentration binder regions are scattered, and the region other than the high-concentration binder region in the gathering portion becomes a low-concentration binder region. Within the aggregated portion, the plurality of high-concentration binder regions may be scattered with regularity or irregularly. In the above-mentioned aggregation portion, the average spacing between adjacent high-concentration binder regions is not particularly limited as long as they are separated.

The arrangement mode of the plurality of high-concentration binder regions in the assembly portion is not particularly limited, but for example, the plurality of high-concentration binder regions are set in the plane of the binder-containing inorganic fiber molded body in the first direction and the above-mentioned first. It can be a mode (first mode) in which one row or two or more rows are arranged in a line shape at a desired interval in at least one direction of a second direction orthogonal to the first direction. Further, as other arrangement modes, for example, a mode in which a plurality of high-concentration binder regions are arranged in a square ring at desired intervals (second aspect), a mode in which a plurality of high-concentration binder regions are arranged in a circumferential direction are desired. A mode in which one or more layers are arranged in an annular row at intervals (third aspect), a plurality of high-concentration binder regions are arranged in an elliptical ring or a polygonal ring at desired intervals. (4th aspect), a plurality of high-concentration binder regions are arranged in a concave polygonal ring like a star shape at desired intervals (fifth aspect), and the like.

In the gathering portion G illustrated in FIG. 7A, a plurality of high-concentration binder regions A are arranged in the first aspect. That is, in the first direction (X direction in FIG. 7A), the three high-concentration binder regions A are arranged in a line shape at equal intervals d3, and are orthogonal to the first direction. It has a three-row × three-row arrangement in which three high-concentration binder regions A are arranged in a line at equal intervals d4 in two directions (Y direction in FIG. 7A). In FIG. 7A, two adjacent gathering portions G are spaced apart by a distance d5 in the first direction (X direction) and separated by a distance d6 in the second direction (Y direction). ..

In the first aspect, in addition to the 3 row × 3 row arrangement embodiment exemplified in FIG. 7 (a), for example, the 1 row × 5 row arrangement embodiment exemplified in FIG. 7 (b) and other arrangement embodiments are used. Can be mentioned. The arrangement mode is not particularly limited. In the first aspect, the number of high concentration binder regions in each row in the first direction and the second direction may be the same or different.

In the gathering portion G illustrated in FIG. 8A, a plurality of high-concentration binder regions A are arranged in the second aspect, and adjacent high-concentration binder regions A are arranged apart from each other at an interval d7. Further, in the gathering portion G exemplified in FIG. 8B, a plurality of high-concentration binder regions A are arranged in the third aspect, and the adjacent high-concentration binder regions A are arranged at intervals d8. There is.

The number of high-concentration binder regions constituting the gathering portion is not particularly limited. Further, the plan-view shape of the gathering portion, the size of each gathering portion, and the like can be appropriately set according to the size and number of the high-concentration binder regions constituting the gathering portion.

The aggregated portions are preferably scattered on at least the first surface of the binder-containing inorganic fiber molded product, and may be scattered on both the first surface and the second surface. The scattered mode of the gathering portion is not particularly limited, and may be provided with regularity or irregularly. The distance between the adjacent gathering portions is not particularly limited, and can be appropriately set according to the size of the gathering portions, the scattered mode, and the like.

As illustrated in FIGS. 8A and 8B, the assembly portion has a recess 2 in which at least a part of a plurality of high-concentration binder regions A contained in one assembly portion G is contained in the inorganic fiber molded body. Although not shown, all of the plurality of high-concentration binder regions contained in one gathering portion may not be located in the recess.

(2) Low-concentration binder region The binder concentration in the low-concentration binder region may be lower than the binder concentration in the high-concentration binder region, and specifically, it is preferably 0% or more and 5.0% or less. It is preferably 0% or more and 4.5% or less, and particularly preferably 0% or more and 4.0% or less. The binder concentration of 0% means that the inorganic fiber molded product does not contain the binder. When the binder concentration in the low-concentration binder region is larger than the above range, the surface frictional force in the low-concentration binder region becomes large, and the frictional force on the entire surface of the binder-containing inorganic fiber molded body due to the low-concentration binder region becomes large. It may be difficult to obtain the reduction effect, or the surface pressure may be low.

The method for obtaining the binder concentration in the low-concentration binder region is not particularly limited, but for example, if the binder is an organic binder, it can be calculated by the following method. That is, the binder-containing inorganic fiber molded product is heated in an electric furnace at about 400 ° C. for 60 seconds to discolor the organic binder, and then a 5 cm square sample is cut out. Next, the region other than the discolored portion (non-discolored region) of the sample is separated, and the mass of the non-discolored region (mass of the non-discolored portion before the binder burning treatment) is measured. Subsequently, the non-discolored region is subjected to a binder burning treatment of heating at 800 ° C. for 1 hour, the organic binder in the non-colored region is burned, and the mass of the non-colored portion after the binder burnout treatment is measured. The mass of the non-discolored region after the binder burnout treatment is defined as the mass of the inorganic fiber in the low-concentration binder region, and the mass difference before and after the binder burnout treatment is defined as the mass of the binder contained in the non-discolored region. The concentration can be determined.

(3) Binder The binder in the present invention is contained in an inorganic fiber molded body and binds inorganic fibers and bundles of inorganic fibers. As the binder, either an organic binder or an inorganic binder can be used.

Examples of the organic binder include various rubbers, water-soluble polymer compounds, thermoplastic resins, thermosetting resins and the like. Specific examples thereof include synthetic rubbers such as acrylic rubber and nitrile rubber; water-soluble polymer compounds such as carboxymethyl cellulose and polyvinyl alcohol; and acrylic resins. The organic binder may be used alone or in combination of two or more. Of these, acrylic rubber, nitrile rubber, carboxymethyl cellulose, polyvinyl alcohol, and acrylic resin not contained in acrylic rubber are preferable. This is because these binders can easily prepare an organic binder liquid and the like, and can easily exert the effects of the organic binder described later.

On the other hand, examples of the inorganic binder include inorganic oxides. Specific examples thereof include alumina, spinel, zirconia, magnesia, titania, calcia, and materials having the same composition as the above-mentioned inorganic fibers. The inorganic binder may be used alone or in combination of two or more. The average particle size of the inorganic oxide is not particularly limited, but can be, for example, 1 μm or less.

The binder contained in the inorganic fiber molded product preferably contains an organic binder. In this case, the binder may be only an organic binder, or may contain both an organic binder and an inorganic binder. The organic binder can be easily impregnated into the inorganic fiber molded product, and can exhibit sufficient thickness binding force even with a relatively low content. Therefore, it is possible to obtain a binder-containing inorganic fiber molded product that is flexible and has excellent strength. Further, the organic binder can be easily thermally decomposed or burned under the operating temperature condition of the binder-containing inorganic fiber molded body.

Here, when an organic binder is used, when the inorganic fiber molded body contains the binder so that the binder concentration is uniform and high with respect to the surface direction of the inorganic fiber molded body, the amount of gas generated by the thermal decomposition of the organic binder or the like. May increase and cause deterioration of the working environment. On the other hand, in the binder-containing inorganic fiber molded body of the present invention, the high-concentration binder region is scattered and the proportion of the low-concentration binder region is larger than that of the high-concentration binder region. It is possible to suppress an increase in the binder concentration in the above.
As a result, even when an organic binder is used, the shearing force can be improved while suppressing the amount of gas generated due to thermal decomposition of the organic binder or the like.

Further, the binder contained in the inorganic fiber molded product preferably contains an inorganic binder. In this case, the binder may be only an inorganic binder, or may contain both an organic binder and an inorganic binder.

When the binder is both an organic binder and an inorganic binder, the blending ratio of the inorganic binder and the organic binder is not particularly limited, but is, for example, in the range of inorganic binder: organic binder = 1: 99 to 90:10 in terms of mass ratio. Can be inside.

The amount of the binder (total amount of the binder) contained in the entire inorganic fiber molded body is particularly limited as long as it has the above-mentioned high-concentration binder region and the above-mentioned low-concentration binder region and the above-mentioned high-concentration binder region can be scattered. However, for example, it can be 0.5 parts by mass or more and 15.0 parts by mass or less with respect to 100 parts by mass of the inorganic fiber in the above-mentioned inorganic fiber molded body in terms of solid content. If the total amount of the binder is too small, the thickness of the binder-containing inorganic fiber molded product may not be obtained. On the other hand, if the total amount of the binder is large, it is assumed that if the binder is an organic binder, the binder is not easily decomposed by heat, and the working environment is deteriorated by the gas generated by the decomposition of the organic binder. For example, the cushioning property may be impaired. Further, since the frictional force on the entire surface of the binder-containing inorganic fiber molded body becomes large and the surface pressure becomes small, problems are likely to occur when press-fitting into the casing. In addition, the cost may be high. The ratio of the mass of the binder to the entire inorganic fiber molded body (binder concentration with respect to the entire inorganic fiber molded body) can be, for example, 0.5% by mass or more and 15.0% by mass or less. For the binder concentration with respect to the entire inorganic fiber molded body, for example, if the binder is an organic binder, the test piece of the binder-containing inorganic fiber molded body of a desired size is subjected to a binder burning treatment in which the test piece is heated at 800 ° C. for 1 hour in an electric furnace. Then, the organic binder in the test piece was burnt down, and the difference in mass between the test pieces before and after the binder burnout treatment was taken as the weight of the binder contained in the test piece, and the mass of the binder, the basis weight of the inorganic fiber molded body, and the test piece were taken. It can be calculated from the size of.

The binder may be colored. This is because the high-concentration binder region and the low-concentration binder region can be easily visually recognized. The coloring binder is not particularly limited, and examples thereof include those in which a known coloring material such as a pigment is added to the above-mentioned organic binder.

The binder can be contained inside the inorganic fiber molded body, for example, by applying a binder solution in which the binder is dispersed in a solvent to the inorganic fiber molded body and impregnating the inorganic fiber molded body. The binder solution may be prepared, and for example, an aqueous solution commercially available as an organic binder solution, an aqueous dispersion type emulsion, latex, an organic solvent solution, or the like can be used as it is or diluted with water or the like.

(4) Others In the binder-containing inorganic fiber forming body of the present invention, the method for specifying the position of the high-concentration binder region is not particularly limited, and any method can be used. For example, in the plane of the first surface of the binder-containing inorganic fiber molded body, a first direction (for example, the width direction of the original fabric of the binder-containing inorganic fiber molded body) and a second direction orthogonal to the first direction (for example, the width direction of the original fabric of the binder-containing inorganic fiber molded body). For example, the length direction of the original fabric of the binder-containing inorganic fiber molded body) is specified, and a plurality of samples are cut out without being separated in each direction or separated at a desired interval, and the mass change of each sample before and after combustion. The position of the high-concentration binder region can be specified from the amount and the cutting position of each sample. If the binder is an organic binder, the position of the high-concentration binder region can be specified from the position of the discolored portion developed by heating the binder-containing inorganic fiber molded body in an electric furnace at about 400 ° C. for 60 seconds. can.

2. 2. Inorganic fiber molded body The inorganic fiber molded body in the present invention is an aggregate of inorganic fibers, and is referred to as, for example, a mat, a blanket, a block, or the like. The inorganic fiber molded body has a first surface and a second surface facing each other, and a plurality of recesses are formed. That is, the first surface and the second surface of the binder-containing inorganic fiber molded body correspond to the first surface and the second surface of the inorganic fiber molded body. The first surface and the second surface of the inorganic fiber molded product may be referred to as a matte surface.

(1) Recessed portion The recessed portion in the inorganic fiber molded body is formed on at least the first surface of the inorganic fiber molded body, and is recessed in the surface of the first surface toward the other surface side rather than the periphery. Is. That is, at least the first surface of the binder-containing inorganic fiber forming body is an uneven surface, and the concave portion opens to at least the first surface.

The recess extends in a direction intersecting the first surface and the second surface of the inorganic fiber molded body. The extending direction of the concave portion may be orthogonal to the first surface and the second surface, or may be oblique to each other. Further, the recess may be a through hole penetrating in a direction intersecting the first surface and the second surface of the inorganic fiber molded body, or may be a non-penetrating hole that does not penetrate. When the recess is a through hole, the recess opens on both the first and second surfaces.

Examples of the recess include needle marks, compression recesses, grooving recesses and the like. The compression recess is a recess formed by applying a smooth molded plate to one surface of the mat and applying a molded plate having ridges corresponding to grooves to the other surface of the mat to compress it. Further, the grooving recess is a recess formed by grooving the inorganic fiber molded body. Above all, the recess is preferably a needle mark. In the needle mark, a plurality of inorganic fibers are oriented in the vertical direction to form an inorganic fiber bundle that is three-dimensionally entangled, and the inorganic fiber is restrained in the inorganic fiber bundle, so that it may have a higher shearing force. Because it can be done. In particular, when the needle mark is located in the low-concentration binder region, it is possible to have a relatively high shearing force in the low-concentration binder region even if the binder is not contained.

9 (a) and 9 (b) are schematic views for explaining the shape of the needle mark. As illustrated in FIG. 9A, the needle mark 2 may be a through hole opened in the first surface 10a and the second surface 10b of the binder-containing inorganic fiber molded body 10, and is shown in FIG. 9B. As an example, it may be a non-through hole that opens only in the first surface 10a of the binder-containing inorganic fiber molded body 10. In FIGS. 9A and 9B, the needle mark 2 extends in a direction orthogonal to the first surface 10a and the second surface 10b.

The depth of the recess is not particularly limited, and can be appropriately set according to the type and shape of the recess, the method of forming the recess, and the like. For example, if the recess is a needle mark, the depth of the needle mark is preferably 50% or more, particularly 80% or more of the average thickness of the binder-containing inorganic fiber molded body (or inorganic fiber molded body). Is preferable. Further, the depth of the needle marks may be 100% of the average thickness of the binder-containing inorganic fiber molded body (or the inorganic fiber molded body), that is, the needle marks may penetrate the thickness direction of the binder-containing inorganic fiber molded body. ..

The plan-view shape of the concave portion is not particularly limited, and can be appropriately set according to the type and shape of the concave portion, the method of forming the concave portion, and the like. For example, a perfect circle, a circle such as an ellipse, a quadrangle such as a square or a rectangle, a polygon, a star shape, or the like can be mentioned. If the recess is a needle mark, the plan view shape of the needle mark is usually circular, preferably a perfect circle.

The size of the recess is not particularly limited, and can be appropriately set according to the type and shape of the recess, the method of forming the recess, and the like. When the recess is a needle mark, the diameter of the needle mark is preferably, for example, 450 μm or more and 700 μm or less, and more preferably 490 μm or more and 600 μm or less. The diameter of the needle mark is the brightness distribution measured in the radial direction of the black spots projected on one surface of the binder-containing inorganic fiber molded body (or inorganic fiber molded body) when visible light is applied to the other surface. It is defined by the half-value width of the peak) and refers to the length indicated by φ2 in FIG. The black spot can be confirmed regardless of whether the needle mark is a through hole or a non-through hole.

Further, the number of recesses (referred to as recess density) per unit area of the binder-containing inorganic fiber molded body (or inorganic fiber molded body) is not particularly limited, and depends on the type and shape of the recesses, the method of forming the recesses, and the like. Can be set as appropriate. When the recess is a needle mark, the larger the number of needle marks per unit area of the binder-containing inorganic fiber molded body (or inorganic fiber molded body) (hereinafter referred to as needle mark density), the higher the shearing force. However, the surface pressure decreases, and the smaller the surface pressure, the larger the surface pressure, but the lower the shearing force. Therefore, it is preferable that the needle mark density has a size capable of achieving a good balance between the shearing force and the surface pressure. The needle scar density is preferably 1.0 pieces / cm ² or more and 50.0 pieces / cm ² or less, and more preferably 15.0 pieces / cm ² or more and 40.0 pieces / cm ² or less. Is preferable, and it is particularly preferable that the number is 20.0 pieces / cm ² or more and 35.0 pieces / cm ² or less. The number of needle marks can be the number of black spots projected on one surface of the binder-containing inorganic fiber molded body or the inorganic fiber molded body when visible light is applied to the other surface. The black spot can be confirmed regardless of whether the needle mark is a through hole or a non-through hole.

The recesses may be formed at equal intervals in a plan view, or may be provided at random. When the recess is a needle mark, the average distance between two adjacent needle marks can be, for example, in the range of 0.1 cm to 4 cm, preferably in the range of 0.1 cm to 3 cm. It can be more preferably in the range of 0.1 cm to 2 cm.

Further, when the recess is a needle mark, a plurality of needle marks may be aggregated to form a needle mark collecting portion. At this time, it is preferable that the needle mark collecting portions are scattered. The arrangement mode of the needle marks in the needle mark collecting portion is not particularly limited, and can be, for example, the same as the arrangement mode of the high concentration binder region in the collecting portion of the high concentration binder region described above.

The recess may be located in the high-concentration binder region, may be located in the low-concentration binder region, or may be located in both the high-concentration binder region and the low-concentration binder region. Here, the fact that the recess is located in the high-concentration binder region means that the recess is included in the high-concentration binder region in the plan view of the binder-containing inorganic fiber molded body. Specifically, when a reference region of 5 cm square is set so as to include the recesses on at least the first surface of the binder-containing inorganic fiber molded body, the recesses included in the reference region have a radius of 4 mm from the center. It means that the binder concentration within the above range is within the range of the binder concentration in the above-mentioned high concentration binder region. As long as the concave portion is located in the high-concentration binder region, the high-concentration binder region A may be larger than the concave portion (needle mark 2) in a plan view as illustrated in FIGS. 1 to 6, and is not shown. The high-concentration binder region and the recess may have the same size in a plan view.

Further, the fact that the recess is located in the low-concentration binder region means that the recess is included in the low-concentration binder region in the plan view of the binder-containing inorganic fiber molded body. Specifically, when a reference region of 5 cm square is set so as to include the recesses on at least the first surface of the binder-containing inorganic fiber molded body, the recesses included in the reference region have a radius of 4 mm from the center. It means that the binder concentration within the above range is within the range of the binder concentration in the above-mentioned low concentration binder region.

In the present invention, it is preferable that the recess is located in at least a part of the high-concentration binder region, and it is more preferable that the needle mark is located in at least a part of the high-concentration binder region. Specifically, when a reference region of 5 cm square is set on at least the first surface of the binder-containing inorganic fiber molded product, recesses are formed in 25% or more of the total number of high-concentration binder regions contained in the reference region. It is preferable that the recesses are located at 50% or more, and it is particularly preferable that the recesses are located at 80% or more. Further, the recess may be located in 100% of the high-concentration binder region, that is, in all the high-concentration binder regions. This is because the concave portion is located in the high-concentration binder region, so that the binder liquid can be easily applied to the concave portion. Further, when the recess is a needle mark, the binder liquid easily permeates the inorganic fiber bundle forming the needle mark, and the high-concentration binder region can be easily scattered and arranged according to the position of the needle mark. Is. Further, since the binder is present in the inorganic fiber bundle at a high concentration in the needle mark, the inorganic fibers of the inorganic fiber bundle can be firmly bound to each other, so that it is possible to have a higher shearing force. This is because it is inferred.

(2) Inorganic fiber molded body Examples of the inorganic fiber constituting the inorganic fiber molded body include silica, alumina / silica, and single fibers or composite fibers containing these such as zirconia, spinel, and titania. Among them, the inorganic fiber is preferably alumina / silica fiber, and particularly preferably crystalline alumina / silica fiber. Alumina / silica fiber is a ceramic fiber containing alumina and silica as main components, and is simply referred to as "alumina fiber". When the inorganic fiber is an alumina / silica fiber (alumina fiber), the composition ratio (mass ratio) of alumina / silica is preferably in the range of 60 to 98/40 to 2, and particularly 70 to 74/30. It is preferably in the range of ~ 26.

The inorganic fiber is preferably a short fiber. This is because the toughness can be increased without impairing the thickness of the inorganic fiber molded product. The term that the inorganic fiber is a short fiber specifically means that the average fiber length of the inorganic fiber is in the range of 210 μm to 1000 μm.

The average fiber diameter of the inorganic fiber is not particularly limited, but is preferably 3 μm or more and 10 μm or less, and more preferably 5 μm or more and 8 μm or less. This is because the repulsive force and toughness of the inorganic fiber are improved, and the strength of the fiber can be increased. If the average fiber diameter of the inorganic fiber is too large, the room temperature compression cycle characteristic (cold compression) of the inorganic fiber molded body is lost, while if the average fiber diameter is too small, the amount of dust suspended in the air is increased. There is a risk of increasing.

3. 3. Others The average thickness of the binder-containing inorganic fiber molded product of the present invention is not particularly limited and can be appropriately set according to the intended use and the like. The average thickness can be, for example, about 2 mm to 50 mm.

4. Production Method The method for producing the binder-containing inorganic fiber molded product of the present invention is not particularly limited as long as it can be formed so that high-concentration binder regions are scattered. If the recess is a binder-containing inorganic fiber molded body in which needle marks are formed, for example, an inorganic fiber molded body forming step of spinning an inorganic fiber to form an inorganic fiber molded body and a needle needle from the first surface of the inorganic fiber molded body. The binder liquid is spot-applied to the first surface of the inorganic fiber molded body in which the needle marks are formed and the needling treatment step of forming needle marks through the fibers, and the liquid is removed from the second surface side facing the first surface. It can be produced through a binder liquid application step of forming a high-concentration binder region and a low-concentration binder region, and a drying step of drying the inorganic fiber molded body after the binder liquid is applied.

As a method for forming the inorganic fiber molded body by the above-mentioned step of forming the inorganic fiber molded body, a known method can be used. For example, it can be the same as the method for forming a mat-like aggregate of an alumina / silica fiber precursor by the spinning process disclosed in International Publication No. 2016/152795. Further, as a method for forming needle marks by the needling treatment step, a known method can be used, and for example, the same as the method for forming needle marks by the needling treatment step disclosed in International Publication No. 2016/152795. can do.

In the binder liquid application step, the method of spot coating the binder liquid is not particularly limited, but for example, the binder liquid is injected from the first surface of the inorganic fiber molded body in which the needle marks are formed by using a dropper or the like. However, a method of draining the liquid from the second surface side can be used. According to this method, the injection region of the binder liquid becomes a high-concentration binder region because the binder liquid is applied, and the region other than the injection region becomes a low-concentration binder region because the binder liquid is not applied. Further, as another method, for example, a mask having a plurality of openings formed is arranged on the first surface of the inorganic fiber molded body in which the needle marks are formed, which is opposite to the inorganic fiber molded body of the mask. Examples thereof include a method in which the binder liquid is applied to the entire surface from the side surface and the liquid is removed from the second surface side of the inorganic fiber molded body. According to this method, the region overlapping the opening of the mask of the inorganic fiber molded body can be a high-concentration binder region because the binder liquid is applied, while the opening of the mask of the inorganic fiber molded body. The region that does not overlap with the binder liquid can be a low-concentration binder region because the binder liquid is not applied. The liquid removal method is not particularly limited, and various liquid removal methods such as suction, pressurization, and compression can be used.

As the drying method by the above-mentioned drying step, a known method can be used, and for example, the drying method disclosed in International Publication No. 2016/080388 can be applied.

5. Applications The binder-containing inorganic fiber molded product of the present invention can be applied to, for example, a heat insulating material, a fireproof material, a cushioning material (holding material), a sealing material, and the like. Above all, it is suitable as a holding material for an exhaust gas purifying device because delamination due to friction is unlikely to occur when press-fitting into the casing and the holding property of the exhaust gas treated body is good.

The present invention is not limited to the above embodiment. The above embodiment is an example, and any one having substantially the same configuration as the technical idea described in the claims of the present invention and having the same effect and effect is the present invention. It is included in the technical scope of the invention.

Examples and comparative examples are shown below, and the present invention will be described in more detail.

[Example 1]
A 200 mm × 300 mm test piece was cut out from an alumina fiber molded body raw roll having multiple needle marks on the first surface (trade name: Mufftech (registered trademark), manufactured by Mitsubishi Chemical Corporation, basis weight 1500 g / m ² ). .. In the above test piece, the recess was a needle mark and the needle mark was a through hole. The density of the needle marks is 2 / cm ² , the average diameter of the needle marks is 654 μm, the average depth of the needle marks is 100% (about 8.0 mm) of the average thickness of the inorganic fiber molded body, and the two needles in close proximity to each other. The average distance between the scars was 1.0 cm.

As shown in FIG. 11A, the needle marks (needle marks) of the test piece S are placed on the conveyor with the first side facing up and the suction blower is operated at an output of 50 Hz on the second side. With respect to 100% of the total number of recesses) 2, the amount of dripping per place is set to 0.05 g, the binder liquid is spot-dropped on the first surface, and the binder liquid is infiltrated from the first surface side to the second surface side. rice field. The dropping region of the binder liquid is the high-concentration binder region A, and the other regions are the low-concentration binder region B. As the binder solution, an organic binder solution (acrylate-based latex, trade name: Nipol (registered trademark), manufactured by Nippon Zeon, concentration 15% by mass) was used, and spot dropping was performed using a 2 mL syringe. Then, it was dried at 140 ° C. for 15 minutes in a state of being restrained to a predetermined thickness by a jig to obtain a binder-containing inorganic fiber molded product. When the obtained binder-containing inorganic fiber molded body was heated in an electric furnace at about 400 ° C. for 60 seconds to discolor the organic binder to develop a discolored portion, 100% of the total number of high-concentration binder regions was needles. It was confirmed that it was located in the scar. The high-concentration binder region specified from the discolored portion is circular in a plan view, has an average diameter of 4.2 mm, an average area of 13.8 mm ² , an average height of about 8.0 mm, and a binder concentration (average). Was 15% by mass. On the other hand, the binder concentration (average) of the low-concentration binder region, which is a region other than the discolored portion, was 0% by mass. The volume ratio of the low-concentration binder region to the plurality of high-concentration binder regions was 2.2. Further, when one reference region R of a square (25 cm square meter) having a side of 5 cm square was set on the first surface of the binder-containing inorganic fiber molded body after heating, the number of high-concentration binder regions included in the reference region R was set. The number was 56, and it was confirmed that high-concentration binder regions were scattered on the first surface. In the binder-containing inorganic fiber molded body of Example 1, the ratio of the mass of the binder per inorganic fiber (binder concentration to the entire inorganic fiber molded body) was 5.13% by mass.

[Example 2]
A 200 mm × 300 mm test piece was cut out from the same alumina fiber molded raw material roll used in Example 1. The details of the needle marks in the test piece were the same as in Example 1. The test piece is placed on a conveyor with the first side facing up, and the suction blower is operated at an output of 50 Hz on the second side, using a 2 mL syringe, as shown in FIG. 11 (b). Binder solution (acrylate-based latex, trade name: Nipol (registered trademark), manufactured by Zeon Corporation, with a dropping amount of 0.05 g per location for 50% of the total number of needle marks (recesses) 2 possessed by S. , Concentration 15% by mass) was spot-dropped on the first surface, and the binder solution was infiltrated from the first surface side to the second surface side. Further, the binder liquid is spot-dropped on the first surface with the dropping amount per place being 0.05 g, one by one between the needle marks 2 where the two adjacent binder liquids are not dropped, and the first surface is spilled from the first surface side. The binder liquid was infiltrated into the two sides. Then, it was dried at 140 ° C. for 15 minutes in a state of being restrained to a predetermined thickness by a jig to obtain a binder-containing inorganic fiber molded product. When the obtained binder-containing inorganic fiber molded body was heated in an electric furnace at about 400 ° C. for 60 seconds to discolor the organic binder to develop a discolored portion, 50% of the total number of high-concentration binder regions was needles. It was confirmed that it was located in the scar and 50% was located in the area other than the needle scar. The high-concentration binder region specified from the discolored portion is circular in a plan view, has an average diameter of 3.6 mm, an average area of 10.2 mm ² , an average height of about 8.0 mm, and a binder concentration (average). Was 15% by mass. On the other hand, the binder concentration (average) of the low-concentration binder region, which is a region other than the discolored portion, was 0% by mass. The volume ratio of the low-concentration binder region to the plurality of high-concentration binder regions was 3.4. Further, when one reference region R of a 25 cm square meter square having a side of 5 cm was set on the first surface of the binder-containing inorganic fiber molded body after heating, the number of high-concentration binder regions included in the reference region R was 56. It was confirmed that the high-concentration binder regions were scattered on the first surface. In the binder-containing inorganic fiber molded body of Example 2, the ratio of the mass of the binder per inorganic fiber (binder concentration to the entire inorganic fiber molded body) was 5.74% by mass.

[Comparison example]
A 200 mm × 300 mm test piece was cut out from the same alumina fiber molded raw material roll used in Example 1, and a binder solution (acrylate-based latex, commercial product) was used so that the binder concentration was made uniform in the plane of the first surface. A binder-containing inorganic fiber molded product was obtained in the same manner as in Example 1 except that Nipol (registered trademark), manufactured by Zeon Corporation, concentration 15% by mass) was uniformly applied to the entire first surface. That is, in the binder-containing inorganic fiber molded product of the comparative example, the high-concentration binder region was not scattered on the first surface. In the binder-containing inorganic fiber molded body of the comparative example, the ratio of the mass of the binder per inorganic fiber (binder concentration to the entire inorganic fiber molded body) was 4.71% by mass.

[evaluation]
The frictional force, shearing force, and surface pressure of the binder-containing inorganic fiber molded bodies of Examples 1 and 2 and Comparative Examples were measured by the following methods. The evaluation results are shown in Table 1 below.

(Friction force)
FIG. 12 is a side view schematically showing a friction force measuring device. First, a 40 mm × 40 mm test piece was die-cut from the prepared binder-containing inorganic fiber molded body to prepare two samples (31) for measuring frictional force. Next, a sample (31) for measuring frictional force was adhered to each of the pair of stainless steel plates (32) with an adhesive tape (33) (Nichiban Co., Ltd., Nystack NW-40 (ordinary)). After that, the stainless steel plate (32) was installed so as to sandwich the stainless sheet (34) for the tensile test (EN 1.4509 surface treatment 2B finish) between the samples (31) for measuring the frictional force. The width of the stainless steel plate was appropriately adjusted by the width adjusting fastener (35) so that the bulk density (GBD) of the inorganic fiber of the sample (31) for measuring the frictional force was 0.3 g / cm ³ . After that, the stainless sheet (34) for tensile test was connected to a measuring device (Technograph, TG) at room temperature (25 ° C.), pulled at a speed of 1000 mm / min, and its peak load F (friction force, N) was measured. did.

(Shearing force)
In the frictional force measuring device shown in FIG. 12, the frictional force measuring method is the same as that of the frictional force measuring method except that the frictional force measuring sample (31) and the tensile test stainless sheet (34) are further adhered with an adhesive tape (33). It was measured. At that time, the obtained peak load S (shearing force, N) was measured.

(Surface pressure)
A 40 mm × 40 mm test piece was punched out from the prepared binder-containing inorganic fiber molded body, and three samples for surface pressure measurement were prepared. Repulsive force after holding for 5 minutes after compressing the three samples for surface pressure measurement until the bulk densities (GBD) are 0.25 g / cm ³ , 0.30 g / cm ³ , and 0.35 g / cm ³ , respectively. (Relaxed surface pressure after 5 minutes) was measured.

From Table 1 above, the binder-containing inorganic fiber molded products of Examples 1 and 2 have a high-concentration binder region and a low-concentration binder region, and the high-concentration binder regions are scattered on at least the first surface, so that the binder is used. It was shown that the frictional force on the entire surface was smaller and the shearing force was higher than that of the binder-containing inorganic fiber molded body of the comparative example in which the concentration was made uniform. Further, regarding the relaxation surface pressure after 5 minutes, the binder-containing inorganic fiber molded products of Examples 1 and 2 showed higher values than the binder-containing inorganic fiber molded products of Comparative Examples, regardless of the size of the bulk density. ..

1 ... Inorganic fiber molded body 2 ... Recesses, needle marks 10 ... Binder-containing inorganic fiber molded body 10a ... First surface 10b ... Second surface A ... High-concentration binder region B ... Low-concentration binder region

Claims (5)

A binder-containing inorganic fiber molded product having a first surface and a second surface facing each other and having a binder contained in an inorganic fiber molded product having a plurality of recesses formed therein.
The binder-containing inorganic fiber molded body has a plurality of high-concentration binder regions having a relatively high binder concentration, and low-concentration binder regions other than the high-concentration binder region having a relatively low binder concentration.
The plurality of high-concentration binder regions extend in a direction intersecting the first surface and the second surface, and are scattered at least on the first surface.
A binder-containing inorganic fiber molded body, wherein the volume ratio of the low-concentration binder region to the plurality of high-concentration binder regions is 1.5 or more and 6.0 or less. The binder concentration in the high-concentration binder region is more than 5% and 25% or less.
The binder-containing inorganic fiber molded product according to claim 1, wherein the binder concentration in the low-concentration binder region is 0% or more and 5% or less. The binder-containing inorganic fiber molded product according to claim 1 or 2, wherein the recess is a needle mark. The binder-containing inorganic fiber molded product according to any one of claims 1 to 3, wherein the recess is located in at least a part of the plurality of high-concentration binder regions. The binder-containing inorganic fiber molded product according to any one of claims 1 to 4, wherein the binder contains an organic binder.

Images