JP7394905B2 - Binder-containing inorganic fiber molded article, holding material for exhaust gas purification device, and method for producing binder-containing inorganic fiber molded article - Google Patents

Description

The present invention relates to a binder-containing inorganic fiber molded article in which a binder is contained in an inorganic fiber molded article, and a method for producing the same.

BACKGROUND ART Inorganic fiber molded articles, which are formed from inorganic fibers such as ceramic fibers into a mat shape, are widely used in applications that are exposed to high temperature conditions, such as industrial insulation materials, fireproof materials, and packing materials. In addition, inorganic fiber molded bodies are used as cushioning materials for automobile exhaust gas purification devices, that is, when the exhaust gas treatment bodies such as catalyst carriers and particle filters are housed in metal casings, they are wound around exhaust gas treatment bodies and It is also used as a holding material for an exhaust gas purification device interposed between the processing body and the casing (GAP).

On the other hand, inorganic fiber molded articles have a problem in that the inorganic fibers fall off and scatter from the surface during processing, assembly, transportation, use, etc., which deteriorates the working environment.

Ceramic fibers are considered to be carcinogenic and may cause health problems, and regulations regarding inorganic fibers are being tightened. For example, according to the World Health Organization (WHO), fibrous substances that are inhaled into the body when humans breathe and reach the lungs are called "respirable fibers," and are defined as ``respirable fibers.'' ratio) is defined as greater than 3. Therefore, when the inorganic fiber molded article contains such respirable fibers, the above-mentioned problem of fiber scattering becomes significant.

Furthermore, in recent years, there has been a trend to place exhaust gas purification devices in high-temperature areas directly below the engine in order to improve catalyst efficiency. Therefore, in order to cope with the widening of GAP at higher temperatures and to prevent leakage of exhaust gas and damage to the exhaust gas treatment body, an inorganic fiber molded body with a high basis weight is required (see, for example, Patent Document 1). However, as the basis weight of the inorganic fiber molded article increases, the amount of inorganic fibers scattered from the surface increases. Therefore, even when the inorganic fiber molded article has a high basis weight, the above-mentioned problem of fiber scattering becomes significant.

Therefore, in order to suppress fiber scattering, it is common practice to include a binder such as an organic binder in an inorganic fiber molded article (see, for example, Patent Document 2).

When a binder is contained in an inorganic fiber molded article, a method is used in which the inorganic fiber molded article is impregnated with a binder liquid containing the binder. In an inorganic fiber molded article with a high basis weight, either the thickness or the bulk density is large, so that the binder liquid is difficult to penetrate. Therefore, even if a binder is contained in a high basis weight inorganic fiber molded article, fiber scattering cannot be sufficiently suppressed.

In addition, Patent Document 2 discloses that when a binder liquid is sprayed onto an inorganic fiber molded object and the binder liquid is penetrated from the surface, the strength of the spraying of the binder liquid is adjusted to improve the quality of the inorganic fiber molded object. It is disclosed that the binder content in the upper, middle and lower parts can be adjusted. However, in the case of an inorganic fiber molded product with a high basis weight, that is, an inorganic fiber molded product with a large bulk density or thickness, the spraying strength of the binder liquid must be increased to allow the binder liquid to penetrate into the inside of the inorganic fiber molded product. If the temperature increases, the structure of the surface layer of the inorganic fiber molded product may be destroyed and its performance may be reduced.

Furthermore, inorganic fiber molded articles containing an organic binder have problems in that combustion gas from the organic binder is generated when used at high temperatures, and odor is generated due to the organic binder and the combustion gas. Therefore, although increasing the amount of organic binder increases the effect of suppressing fiber scattering, due to the increasing environmental problems in recent years, it is required to reduce the amount of organic binder as much as possible (see, for example, Patent Document 3).

Patent No. 6870787 Patent No. 4042305 Patent No. 4665618

As described above, in the case of an inorganic fiber molded article having a high basis weight, it is difficult to achieve both a low binder amount and low dust generation. Therefore, although there is a need for a high basis weight inorganic fiber molded article, it has not been put into practical use because it is difficult to solve the problem of fiber scattering and it is difficult to increase added value. Therefore, there is currently no binder-containing inorganic fiber molded product that uses a high basis weight inorganic fiber molded product, has a reduced amount of binder, and can suppress fiber scattering.

The present invention has been made in view of the above-mentioned circumstances, and its main purpose is to provide a binder-containing inorganic fiber molded article that can suppress fiber scattering even when the basis weight is high and the amount of binder is low.

In order to achieve the above object, the present invention provides a binder-containing inorganic fiber molded article, in which a binder is contained in an inorganic fiber molded article, wherein the basis weight of the inorganic fiber molded article is more than 2600 g/ ^m2 . The content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less based on 100 parts by mass of the inorganic fiber molded product, and the 50 mm square binder-containing inorganic fiber molded product is When a shaking test was performed in which the sieve was placed in a 4 mm sieve and was shaken under the conditions of vertical reciprocating shaking method, amplitude of 2 mm, shaking speed of 3000 reciprocations/min, and vibration time of 10 minutes, the above shaking The present invention provides a binder-containing inorganic fiber molded article in which the weight reduction rate of the binder-containing inorganic fiber molded article before and after a test is 1.0% or less.

Further, the present invention provides a binder-containing inorganic fiber molded article, wherein the inorganic fiber molded article contains a binder, and the bulk density of the inorganic fiber molded article when free is 0.10 g/cm ³ or more. 20 g/cm ³ or less, the content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less based on 100 parts by mass of the inorganic fiber molded body, and the binder-containing inorganic fiber is 50 mm square. A shaking test was conducted in which the molded product was placed in a sieve with an opening of 4 mm, and the sieve was shaken under the conditions of vertical reciprocating shaking, an amplitude of 2 mm, a shaking speed of 3000 reciprocations/min, and a vibration time of 10 minutes. The present invention provides a binder-containing inorganic fiber molded article in which the weight reduction rate of the binder-containing inorganic fiber molded article before and after the shaking test is 1.0% or less.

Furthermore, the present invention provides a binder-containing inorganic fiber molded article, wherein the inorganic fiber molded article contains a binder, wherein the basis weight of the inorganic fiber molded article is more than 2,600 g/m ² , and the binder-containing inorganic When the fiber molded body is divided into three equal parts in the thickness direction and defined as a first region, a second region, and a third region from one side of the binder-containing inorganic fiber molded body, the inorganic fibers contained in each region are 100. The maximum value of the content of the binder in each region based on parts by mass is 2.24 parts by mass or less, and a 50 mm square binder-containing inorganic fiber molded article is placed in a sieve with an opening of 4 mm, and the above-mentioned When a shaking test was conducted in which the sieve was shaken under the conditions of vertical reciprocating shaking method, amplitude of 2 mm, shaking speed of 3000 reciprocations/min, and vibration time of 10 minutes, the binder-containing inorganic content before and after the shaking test was Provided is a binder-containing inorganic fiber molded article having a weight reduction rate of 1.0% or less.

Further, the present invention provides a binder-containing inorganic fiber molded article, wherein the inorganic fiber molded article contains a binder, and the bulk density of the inorganic fiber molded article when free is 0.10 g/cm ³ or more. The binder-containing inorganic fiber molded product is divided into three equal parts in ^the thickness direction, and the binder-containing inorganic fiber molded product is divided into a first region, a second region, and a third region from one side of the binder-containing inorganic fiber molded product. In this case, the maximum content of the binder in each region is 0.01 parts by mass or more and 2.24 parts by mass or less with respect to 100 parts by mass of inorganic fibers contained in each region, and The binder-containing inorganic fiber molded article is placed in a sieve with an opening of 4 mm, and the sieve is shaken in a vertical reciprocating manner, with an amplitude of 2 mm, a shaking speed of 3000 reciprocations/min, and a vibration time of 10 minutes. Provided is a binder-containing inorganic fiber molded article, in which the weight reduction rate of the binder-containing inorganic fiber molded article before and after the shaking test is 1.0% or less when a shaking test is performed.

Further, in the present invention, the binder-containing inorganic fiber molded product is divided into three equal parts in the thickness direction, and these are defined as a first region, a second region, and a third region from one side of the binder-containing inorganic fiber molded product. In this case, the maximum content of the binder in each region is preferably 0.01 parts by mass or more and 2.24 parts by mass or less, based on 100 parts by mass of the inorganic fibers contained in each region.

In the above case, the difference between the content of the binder in the binder-containing inorganic fiber molded article and the maximum value of the content of the binder in each region is preferably 0.75 parts by mass or less. .

Moreover, in the present invention, it is preferable that the binder is an organic binder.

Further, in the present invention, it is preferable that the inorganic fiber molded article contains alumina fiber.

Moreover, in the present invention, it is preferable that the inorganic fiber molded article is a needle blanket.

Further, the present invention provides a holding material for an exhaust gas purification device, which has the above-described binder-containing inorganic fiber molded article.

Furthermore, the present invention provides a method for producing a binder-containing inorganic fiber molded article, which includes an impregnating step of impregnating an inorganic fiber molded article with a binder liquid containing a binder, wherein the basis weight of the inorganic fiber molded article is 2600 g/ ^m2 , the content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less, based on 100 parts by mass of the inorganic fiber molded body, and the binder liquid is supplied in the impregnation step. Provided is a method for producing a binder-containing inorganic fiber molded article, wherein the binder content is 5% by volume or more based on 100% by volume of the above-mentioned inorganic fiber molded product.

The present invention also provides a method for producing a binder-containing inorganic fiber molded article, which includes an impregnation step of impregnating an inorganic fiber molded article with a binder solution containing a binder, wherein the bulk density of the inorganic fiber molded article when free is , 0.10 g/cm ³ or more and 0.20 g/cm ³ or less, and the content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less based on 100 parts by mass of the inorganic fiber molded article. and the amount of the binder liquid supplied in the impregnation step is 5% by volume or more with respect to 100% by volume of the inorganic fiber molded product.

Further, in the present invention, the method of impregnating the inorganic fiber molded body with the binder liquid is a method of applying the binder liquid to the inorganic fiber molded body, and is a method other than the dipping method, or It is preferable to use a method in which a part of the inorganic fiber molded body is immersed in the binder liquid, or a method in which the binder liquid is injected into the inorganic fiber molded body.

The binder-containing inorganic fiber molded article of the present invention has the effect of suppressing fiber scattering when the basis weight is high and the amount of binder is low.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows an example of the binder containing inorganic fiber molded object of this invention.

Hereinafter, the method for manufacturing the binder-containing inorganic fiber molded article, the holding material for an exhaust gas purification device, and the binder-containing inorganic fiber molded article of the present invention will be described.

A. Binder-containing inorganic fiber molded article The binder-containing inorganic fiber molded article of the present invention has four embodiments. Each embodiment will be described below.

I. First embodiment of binder-containing inorganic fiber molded article The binder-containing inorganic fiber molded article of this embodiment is a binder-containing inorganic fiber molded article in which a binder is contained in the inorganic fiber molded article, and the inorganic fiber molded article described above is a binder-containing inorganic fiber molded article. has a basis weight of more than 2600 g/m ² , the content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less based on 100 parts by mass of the inorganic fiber molded article, and a 50 mm square The binder-containing inorganic fiber molded article is placed in a sieve with an opening of 4 mm, and the sieve is shaken in a vertical reciprocating manner, with an amplitude of 2 mm, a shaking speed of 3000 reciprocations/min, and a vibration time of 10 minutes. When a shaking test is conducted, the weight reduction rate of the binder-containing inorganic fiber molded article before and after the shaking test is 1.0% or less.

In this embodiment, an inorganic fiber molded article with a high basis weight is used, and the content of the binder is small. Even in such a case, since the weight reduction rate of the binder-containing inorganic fiber molded article before and after the above-mentioned shaking test is below a predetermined value, it is possible to suppress fiber scattering and reduce the amount of dust generated. Therefore, an appropriate working environment can be ensured, and an environmentally safe binder-containing inorganic fiber molded article can be provided.

Each structure of the binder-containing inorganic fiber molded article of this embodiment will be explained below.

1. Inorganic fiber molded article The inorganic fiber molded article in this embodiment is an aggregate of inorganic fibers, and is called, for example, a mat, blanket, or block.

The basis weight of the inorganic fiber molded article is more than 2,600 g/m ² , preferably 2,800 g/m ² or more, more preferably 3,000 g/m ² or more. In this embodiment, even if the basis weight of the inorganic fiber molded product is as high as within the above range, the amount of dust generated by the binder-containing inorganic fiber molded product can be reduced. On the other hand, the upper limit of the basis weight of the inorganic fiber molded product is not particularly limited, but for example, preferably 10,000 g/m ² or less, more preferably 7,000 g/m ² or less, still more preferably 5,000 g/m ² It is as follows. If the basis weight of the inorganic fiber molded product is too high, the inorganic fiber molded product will become thick, which may make it difficult to assemble the binder-containing inorganic fiber molded product or increase the cost.

The basis weight of the inorganic fiber molded product can be controlled by adjusting the bulk density and thickness of the inorganic fiber molded product when it is free.

The bulk density of the inorganic fiber molded article when free is, for example, preferably 0.10 g/cm ³ or more and 0.20 g/cm ³ or less, and 0.13 g/cm ³ or more and 0.20 g/cm ³ or less. More preferably, it is 0.15 g/cm ³ or more and 0.20 g/cm ³ or less. In this embodiment, even if the free bulk density of the inorganic fiber molded product is as high as within the above range, the amount of dust generated by the binder-containing inorganic fiber molded product can be reduced. On the other hand, if the bulk density of the inorganic fiber molded article when free is too high, it will become hard, which may reduce moldability. Furthermore, if the bulk density of the inorganic fiber molded product when free is too low, the mechanical strength of the molded product may decrease. In addition, the bulk density of the inorganic fiber molded article in a free state refers to the bulk density of the inorganic fiber molded article in a free state before the binder is contained.

The thickness of the inorganic fiber molded product is preferably a thickness that satisfies the above-mentioned basis weight and bulk density, and can be appropriately set depending on the above-mentioned basis weight and bulk density, use, etc.

The inorganic fibers constituting the inorganic fiber molded body are not particularly limited, and include, for example, ceramic fibers, biosoluble fibers (alkali earth silicate fibers), rock wool, basalt fibers, potassium titanate fibers, calcium silicate fibers, and glass. Fibers etc. can be used. Examples of ceramic fibers include single fibers or composite fibers such as silica, alumina, alumina/silica, zirconia containing these, spinel, titania, and calcia. Among these, the inorganic fibers are preferably alumina/silica fibers, particularly crystalline alumina/silica fibers. Alumina/silica fibers are ceramic fibers whose main components are alumina and silica, and are simply referred to as "alumina fibers." When the inorganic fiber is alumina/silica fiber (alumina fiber), the composition ratio (mass ratio) of alumina/silica is preferably within the range of 60/40 to 98/2, for example, 65/35 to 95. It is more preferably within the range of /5, and preferably within the range of 70/30 to 80/20.

The inorganic fibers are preferably short fibers. This is because the toughness can be increased without impairing the thickness of the inorganic fiber molded article. The inorganic fibers being short fibers means, for example, that the average fiber length of the inorganic fibers is 1,000 mm or less. Further, when the inorganic fibers are short fibers, the average fiber length of the inorganic fibers may be, for example, within the range of 210 μm or more and 1000 μm or less.

The average fiber diameter of the inorganic fibers is not particularly limited, but is preferably, for example, 3 μm or more and 15 μm or less, more preferably 4 μm or more and 13 μm or less, even more preferably 5 μm or more and 10 μm or less, particularly preferably 5 μm or more and 8 μm or less. This is because the repulsive force and toughness of the inorganic fibers are improved, and the strength of the fibers can be increased. Note that if the average fiber diameter of the inorganic fibers is too large, there is a risk that the cold compression cycle characteristics (cold compression) of the inorganic fiber molded article will be lost. On the other hand, if the average fiber diameter of the inorganic fibers is too small, there is a risk that the amount of dust floating in the air will increase, or that more fibrous substances will reach the lungs when inhaled.

The inorganic fiber molded article is preferably a needle blanket. A needle blanket is a needled inorganic fiber molded body. By the needling treatment, not only a strong inorganic fiber molded article in which the inorganic fibers constituting the inorganic fiber molded article are entwined can be obtained, but also the thickness of the inorganic fiber molded article can be adjusted.

When the inorganic fiber molded body is a needle blanket, it has a plurality of needle marks, that is, it has a plurality of recesses. The needle marks may be through holes that penetrate in the thickness direction of the inorganic fiber molded body, or may be non-through holes that do not penetrate through the inorganic fiber molded body.

The number of needle marks per unit area of the inorganic fiber molded product (hereinafter referred to as needle mark density) is not particularly limited, but the larger the number, the higher the shear force but the lower the contact pressure, and the smaller the number, the higher the contact pressure. However, the shear force will be lower. Therefore, it is preferable that the needle mark density is such that it is possible to maintain a good balance between shear force and surface pressure. The density of needle marks can be, for example, 1.0 pieces/cm ² or more and 50.0 pieces/cm ² or less.

Here, when visible light is applied to one surface of the inorganic fiber molded object, the amount of transmitted light at the needle mark is greater than the amount of transmitted light in the area other than the needle mark, so the transmitted light is applied to the other surface of the inorganic fiber molded object. Observed as a light spot. Therefore, the number of needle marks can be determined by applying visible light to one surface of the inorganic fiber molded object and counting the light spots that are transmitted to the other surface of the inorganic fiber molded object. Note that the above-mentioned light spot can be confirmed whether the needle mark is a through hole or a non-through hole.

The needle marks may be provided at equal intervals in a plan view, or may be provided at random. The average distance between two adjacent needle marks can be, for example, 0.1 cm or more and 4 cm or less.

The inorganic fiber molded article may be elongated or sheet-like.

2. Binder The binder in this embodiment is included in the inorganic fiber molded article and binds the inorganic fibers and inorganic fiber bundles. As the binder, both organic binders and inorganic binders can be used.

Examples of the organic binder include various rubbers, water-soluble polymer compounds, thermoplastic resins, thermosetting resins, and the like. Specific examples 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. Among these, acrylic rubber, nitrile rubber, carboxymethyl cellulose, polyvinyl alcohol, and acrylic resins not included in acrylic rubber are preferred. This is because these organic binders are easy to prepare an organic binder liquid and easily exhibit the effects of the organic binder described below.

On the other hand, examples of the inorganic binder include inorganic oxides. Specific examples 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.

Preferably, the binder includes 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. Among these, the binder is preferably an organic binder. This is because organic binders are more easily impregnated into inorganic fiber molded bodies than inorganic binders. Moreover, the organic binder can be easily thermally decomposed or burned out under the operating temperature conditions of the binder-containing inorganic fiber molded article. Therefore, the repulsive force of the inorganic fiber molded body can be restored, and the binder-containing inorganic fiber molded body can be suitably used, for example, as a holding material for an exhaust gas purification device.

In this embodiment, the content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less, and 0.10 parts by mass or more and 1.50 parts by mass or less, based on 100 parts by mass of the inorganic fiber molded body. It is more preferable that there be. In this embodiment, when using a high basis weight inorganic fiber molded product, even if the binder content is as low as within the above range, the amount of dust generated by the binder-containing inorganic fiber molded product can be reduced. I can do it.

Further, in this embodiment, as shown in FIG. 1, for example, the binder-containing inorganic fiber molded body 1 is divided into three equal parts in the thickness direction D, and the first region is divided from one surface side of the binder-containing inorganic fiber molded body 1. 1a, second region 1b, and third region 1c, the maximum value of the binder content in each region is 0.01 parts by mass or more with respect to 100 parts by mass of inorganic fibers contained in each region. It is preferably at most parts by mass, and more preferably from 0.10 parts by mass to 1.50 parts by mass.

In this case, the difference between the binder content of the binder-containing inorganic fiber molded body and the maximum value of the binder content of each region is preferably 0.75 parts by mass or less, and 0.70 parts by mass or less. More preferably, it is 0.60 parts by mass or less. If the difference in binder content is within the above range, it can be considered that the binder is contained without being unevenly distributed in all the first, second, and third regions. Therefore, the portion where inorganic fibers or inorganic fiber bundles are bound by the binder can be increased, and the amount of dust generated from the binder-containing inorganic fiber molded article can be further reduced.

Further, it is preferable that a binder is contained in all the first, second, and third regions. As described above, the portion where inorganic fibers or inorganic fiber bundles are bound by the binder can be increased, and the amount of dust generated from the binder-containing inorganic fiber molded article can be further reduced.

In this case, in the first region, the second region, and the third region, the content of the binder in each region is, for example, 0.01 parts by mass or more and 2.24 parts by mass with respect to 100 parts by mass of inorganic fibers contained in each region. The amount is preferably not more than 0.10 parts by mass and not more than 1.50 parts by mass. If the binder content in each region is within the above range, the binder can bind inorganic fibers and inorganic fiber bundles in all the first, second and third regions, and the binder-containing inorganic The amount of dust generated from the fiber molded article can be further reduced.

Moreover, in the first region, the second region, and the third region, the content of the binder in each region may be the same or different.

In addition, in the binder-containing inorganic fiber molded article, the binder content refers to the ratio (%) of the mass of the binder to the mass of the inorganic fiber molded article. Furthermore, in the first region, second region, and third region, the binder content in each region is the ratio (%) of the mass of the binder contained in each region per the mass of inorganic fibers contained in each region. say.

Here, the method of determining the binder content in the binder-containing inorganic fiber molded article is not particularly limited, but for example, when the binder is an organic binder, it can be calculated by the following method. That is, first, a 50 mm square sample is cut out from a binder-containing inorganic fiber molded article. Next, a binder burning-off treatment is performed in which the sample of the binder-containing inorganic fiber molded body is heated at 800° C. for 1 hour to burn off the organic binder. In addition, the mass before and after the binder burnout treatment is measured. Note that the mass after the binder burning-off treatment corresponds to the mass of the inorganic fiber molded body constituting the binder-containing inorganic fiber molded body. Moreover, the difference in mass before and after the binder burning-off treatment corresponds to the mass of the organic binder contained in the binder-containing inorganic fiber molded article. Then, the content of the binder in the binder-containing inorganic fiber molded article is calculated using the following formula (1).
Binder content (%) = (mass before binder burnout treatment - mass after binder burnout treatment) / mass after binder burnout treatment x 100 (1)

Furthermore, in the first region, second region, and third region, the method of calculating the binder content in each region is not particularly limited, but for example, if the binder is an organic binder, it can be calculated by the following method. can. That is, first, the binder-containing inorganic fiber molded product is divided into three equal parts in the thickness direction, and the binder-containing inorganic fiber molded product is divided into a first region, a second region, and a third region from one surface side. Next, a 50 mm square sample is cut out from each area. A binder burnout treatment is performed in which the sample in each region is heated at 800° C. for 1 hour to burn off the organic binder. In addition, the mass before and after the binder burnout treatment is measured. Note that the mass after the binder burnout process corresponds to the mass of the inorganic fibers included in each region. Further, the difference in mass before and after the binder burning-off treatment corresponds to the mass of the organic binder contained in each region. Then, the content of the binder in each region is calculated using the above formula (1).

In addition, the method for confirming that the binder is contained in each region in the first region, second region, and third region is not particularly limited, but for example, if the binder is an organic binder, the following method may be used. The presence or absence of an organic binder can be confirmed. That is, first, the binder-containing inorganic fiber molded product is divided into three equal parts in the thickness direction, and the binder-containing inorganic fiber molded product is divided into a first region, a second region, and a third region from one surface side. Next, a 50 mm square sample is cut out from each area. A binder burnout treatment is performed in which the sample in each region is heated at 800° C. for 1 hour to burn off the organic binder. In addition, the mass before and after the binder burnout treatment is measured. The difference in mass before and after the binder burnout process corresponds to the mass of the organic binder contained in each region. Therefore, if the mass after the binder burnout treatment is less than the mass before the binder burnout treatment, it is determined that the organic binder is contained.

3. Weight loss rate of binder-containing inorganic fiber molded product before and after shaking test In this embodiment, a 50 mm square binder-containing inorganic fiber molded product was placed in a sieve with 4 mm openings, and the sieve was shaken vertically back and forth. When a shaking test was conducted under the following conditions: amplitude 2 mm, shaking speed 3000 reciprocations/min, and vibration time 10 minutes, the weight loss rate of the binder-containing inorganic fiber molded article before and after the shaking test was 1. It is 0% or less, preferably 0.9% or less, and more preferably 0.8% or less. When the weight reduction rate is within the above range, fiber scattering can be suppressed and the amount of dust generated can be reduced. Note that the lower limit is not particularly limited because the lower the weight loss rate is, the more preferable it is.

The shaking test is performed using the following method. First, a 50 mm square sample is cut out from a binder-containing inorganic fiber molded article. Next, a sample of the binder-containing inorganic fiber molded body is placed in a sieve. A sieve with a diameter of 200 mm and an opening of 4 mm is used as the sieve. The sieve is then mounted on a shaker. As the shaking machine, for example, "ANALYSETTE3" manufactured by FRITSCH can be used. Next, using a shaker, a shaking test is performed in which the sieve is shaken in a vertical reciprocating manner, an amplitude of 2 mm, a shaking speed of 3000 reciprocations/min, and a vibration time of 10 minutes. In addition, the weight of the binder-containing inorganic fiber molded article before and after the shaking test is measured. Then, the weight loss rate of the binder-containing inorganic fiber molded article before and after the shaking test is calculated using the following formula (2).
Weight reduction rate (%) = (Weight of binder-containing inorganic fiber molded product before shaking test - Weight of binder-containing inorganic fiber molded product after shaking test) / Weight of binder-containing inorganic fiber molded product before shaking test ×100 (2)

Further, in the binder-containing inorganic fiber molded article, three samples of 50 mm square were cut out at random, each sample was subjected to the above-mentioned shaking test, the above-mentioned weight loss rate was calculated, and the average value was obtained. This average value is adopted as the weight loss rate of the binder-containing inorganic fiber molded article before and after the shaking test. Note that three samples sampled from the same binder-containing inorganic fiber molded article may be subjected to the shaking test at the same time, as long as their weights are measured individually.

4. Others The average thickness of the binder-containing inorganic fiber molded article of this embodiment is not particularly limited, and can be set as appropriate depending on the application and the like. The average thickness can be, for example, about 2 mm or more and 50 mm or less.

5. Applications Applications of the binder-containing inorganic fiber molded article of this embodiment include, for example, heat insulation applications, fireproof applications, architectural applications, automotive applications, and the like. Specifically, the binder-containing inorganic fiber molded article of this embodiment can be applied to, for example, a heat insulating material, a fireproof material, a cushioning material (holding material), a sealing material, a packing material, and the like. Among them, the binder-containing inorganic fiber molded article of this embodiment has a high basis weight and a low binder amount, and is therefore suitable as a holding material for an exhaust gas purification device.

II. Second embodiment of binder-containing inorganic fiber molded article The binder-containing inorganic fiber molded article of the present embodiment is a binder-containing inorganic fiber molded article in which a binder is contained in the inorganic fiber molded article, and the inorganic fiber molded article described above is a binder-containing inorganic fiber molded article. The bulk density when free is 0.10 g/cm ³ or more and 0.20 g/cm ³ or less, and the content of the binder is 0.01 parts by mass or more based on 100 parts by mass of the inorganic fiber molded product. The binder-containing inorganic fiber molded article containing 2.24 parts by mass or less and having a size of 50 mm square was placed in a sieve with an opening of 4 mm, and the sieve was shaken vertically in a reciprocating manner with an amplitude of 2 mm and a shaking speed of 3000 reciprocations/ When a shaking test is carried out under conditions of shaking for 10 minutes and a vibration time of 10 minutes, the weight loss rate of the binder-containing inorganic fiber molded article before and after the shaking test is 1.0% or less.

In this embodiment, an inorganic fiber molded article having a high bulk density and a high basis weight is used, and the content of the binder is small. Even in such a case, since the weight reduction rate of the binder-containing inorganic fiber molded article before and after the above-mentioned shaking test is below a predetermined value, it is possible to suppress fiber scattering and reduce the amount of dust generated. Therefore, an appropriate working environment can be ensured, and an environmentally safe binder-containing inorganic fiber molded article can be provided.

The structure of the binder-containing inorganic fiber molded article of this embodiment can be the same as that of the binder-containing inorganic fiber molded article of the first embodiment, so the explanation here will be omitted.

III. Third embodiment of binder-containing inorganic fiber molded article The binder-containing inorganic fiber molded article of this embodiment is a binder-containing inorganic fiber molded article in which a binder is contained in the inorganic fiber molded article, and the inorganic fiber molded article described above is a binder-containing inorganic fiber molded article. has a basis weight of more than 2600 g/m ² , and the binder-containing inorganic fiber molded product is divided into three equal parts in the thickness direction, and a first region and a second region are divided from one surface side of the binder-containing inorganic fiber molded product. , when the third region is set, the maximum value of the content of the binder in each region is 2.24 parts by mass or less based on 100 parts by mass of inorganic fibers contained in each region, and the 50 mm square The binder-containing inorganic fiber molded product was placed in a sieve with an opening of 4 mm, and the sieve was shaken under the following conditions: vertical reciprocating shaking method, amplitude of 2 mm, shaking speed of 3000 reciprocations/min, and vibration time of 10 minutes. When a shaking test is conducted, the weight reduction rate of the binder-containing inorganic fiber molded article before and after the shaking test is 1.0% or less.

In this embodiment, the maximum value of the binder content in each region obtained by dividing the binder-containing inorganic fiber molded article into three equal parts in the thickness direction is within a predetermined range and is small. Therefore, the binder content of the binder-containing inorganic fiber molded article can also be considered to be low. Moreover, in this embodiment, an inorganic fiber molded article with a high basis weight is used, and the content of the binder is small. Even in such a case, since the weight reduction rate of the binder-containing inorganic fiber molded article before and after the above-mentioned shaking test is below a predetermined value, it is possible to suppress fiber scattering and reduce the amount of dust generated. Therefore, an appropriate working environment can be ensured, and an environmentally safe binder-containing inorganic fiber molded article can be provided.

Moreover, in this embodiment, it is preferable that the difference between the binder content of the binder-containing inorganic fiber molded body and the maximum value of the binder content of each region is 0.75 parts by mass or less. If the difference in binder content is within the above range, it can be considered that the binder is contained without being unevenly distributed in all the first, second, and third regions. Therefore, the portion where inorganic fibers or inorganic fiber bundles are bound by the binder can be increased, and the amount of dust generated from the binder-containing inorganic fiber molded article can be further reduced.

The structure of the binder-containing inorganic fiber molded article of this embodiment can be the same as that of the binder-containing inorganic fiber molded article of the first embodiment, so the explanation here will be omitted.

IV. Fourth embodiment of binder-containing inorganic fiber molded article The binder-containing inorganic fiber molded article of this embodiment is a binder-containing inorganic fiber molded article in which a binder is contained in the inorganic fiber molded article, and the inorganic fiber molded article described above is The bulk density when free is 0.10 g/cm ³ or more and 0.20 g/cm ³ or less, and the binder-containing inorganic fiber molded product is divided into three equal parts in the thickness direction, and the binder-containing inorganic fiber molded product is When the first region, the second region, and the third region are defined from one surface side, the maximum value of the content of the binder in each region is 0 with respect to 100 parts by mass of inorganic fibers contained in each region. The binder-containing inorganic fiber molded article containing .01 parts by mass or more and 2.24 parts by mass or less and having a size of 50 mm square was placed in a sieve with an opening of 4 mm, and the sieve was shaken in a vertical reciprocating manner with an amplitude of 2 mm. When a shaking test is conducted under the conditions of a shaking speed of 3000 reciprocations/min and a vibration time of 10 minutes, the weight loss rate of the binder-containing inorganic fiber molded article before and after the shaking test is 1.0% or less. be.

In this embodiment, the maximum value of the binder content in each region obtained by dividing the binder-containing inorganic fiber molded article into three equal parts in the thickness direction is within a predetermined range and is small. Therefore, the binder content of the binder-containing inorganic fiber molded article can also be considered to be low. Further, in this embodiment, an inorganic fiber molded article having a high bulk density and a high basis weight is used, and the content of the binder is small. Even in such a case, since the weight reduction rate of the binder-containing inorganic fiber molded article before and after the above-mentioned shaking test is below a predetermined value, it is possible to suppress fiber scattering and reduce the amount of dust generated. Therefore, an appropriate working environment can be ensured, and an environmentally safe binder-containing inorganic fiber molded article can be provided.

Moreover, in this embodiment, it is preferable that the difference between the binder content of the binder-containing inorganic fiber molded body and the maximum value of the binder content of each region is 0.75 parts by mass or less. If the difference in binder content is within the above range, it can be considered that the binder is contained without being unevenly distributed in all the first, second, and third regions. Therefore, the portion where inorganic fibers or inorganic fiber bundles are bound by the binder can be increased, and the amount of dust generated from the binder-containing inorganic fiber molded article can be further reduced.

The structure of the binder-containing inorganic fiber molded article of this embodiment can be the same as that of the binder-containing inorganic fiber molded article of the first embodiment, so the explanation here will be omitted.

B. Holding material for exhaust gas purification device The holding material for exhaust gas purification device of the present invention has the above-mentioned binder-containing inorganic fiber molded body. A holding material for an exhaust gas purification device is a holding material for an exhaust gas treatment body such as a catalyst carrier or a particle filter, and is wound around the exhaust gas treatment body when the exhaust gas treatment body is housed in a metal casing, and is used to hold the exhaust gas treatment body such as a catalyst carrier or a particle filter. This is a holding material for an exhaust gas purification device that is interposed between the body and the casing. The holding material for an exhaust gas purification device of the present invention is composed of the above-mentioned binder-containing inorganic fiber molded article. Specifically, the above-mentioned binder-containing inorganic fiber molded product is subjected to shape processing such as cutting to obtain a holding material for an exhaust gas purification device.

C. Method for producing a binder-containing inorganic fiber molded article The method for producing a binder-containing inorganic fiber molded article of the present invention has two embodiments. Each embodiment will be described below.

I. First embodiment of the method for producing a binder-containing inorganic fiber molded article The present invention in this embodiment is a method for producing a binder-containing inorganic fiber molded article, which includes an impregnating step of impregnating an inorganic fiber molded article with a binder solution containing a binder. The basis weight of the inorganic fiber molded product is more than 2,600 g/m ² , and the content of the binder is 0.01 parts by mass or more and 2.24 parts by mass based on 100 parts by mass of the inorganic fiber molded product. Provided is a method for producing a binder-containing inorganic fiber molded article, wherein the amount of the binder liquid supplied in the impregnation step is 5% by volume or more with respect to 100% by volume of the inorganic fiber molded product. .

In this embodiment, a high basis weight inorganic fiber molded body is used. Even in such a case, the entire inorganic fiber molded body can be impregnated with the binder liquid by relatively increasing the amount of the binder liquid supplied in the impregnation step. Therefore, even when the binder content in the binder-containing inorganic fiber molded article is relatively small, fiber scattering can be suppressed. Therefore, when using an inorganic fiber molded article with a high basis weight, it is possible to reduce the amount of dust generated while reducing the content of the binder. That is, in the case of a high basis weight inorganic fiber molded article, it is possible to achieve both a low binder amount and low dust generation.

Each step in the method for producing a binder-containing inorganic fiber molded article according to the present embodiment will be described below.

1. Impregnation Step In this embodiment, an impregnation step is performed in which the inorganic fiber molded body is impregnated with a binder liquid containing a binder.

In this embodiment, the amount of the binder liquid supplied in the impregnation step is 5% by volume or more, preferably 10% by volume or more, more preferably 50% by volume or more, based on 100% by volume of the inorganic fiber molded body. More preferably, it is 100% by volume or more. By increasing the amount of the binder liquid supplied within the above range, the entire inorganic fiber molded article can be impregnated with the binder liquid. Thereby, fiber scattering can be suppressed and the amount of dust generated can be reduced. On the other hand, the upper limit of the supply amount of the binder liquid is not particularly limited, but if it is too large, the effect will be saturated. Therefore, from the viewpoint of cost and workability in processes after the impregnation process such as the drying process, the supply amount of the binder liquid is, for example, 1000% by volume or less, and may be 500% by volume or less. , 300% by volume or less.

The inorganic fiber molded product is the same as the inorganic fiber molded product described in the above section "A. Inorganic fiber molded product I. First embodiment", so the explanation here will be omitted.

As a method for producing an inorganic fiber molded article, a known method can be used. For example, there is a method disclosed in International Publication No. 2016/152795.

Further, the binder contained in the binder liquid is also the same as the binder described in the above section "A. Inorganic fiber molded article I. First embodiment", so the explanation here will be omitted.

The solvent and dispersion medium contained in the binder liquid are appropriately selected depending on the type of binder and binder liquid, and include water, organic solvents, and the like. The solvent and dispersion medium may be used alone or in combination of two or more.

In the case of an organic binder, an aqueous solution, water-dispersed emulsion, latex, or organic solvent solution containing the organic binder can be used as the binder liquid. In particular, emulsions are preferred. The binder liquid may be prepared or a commercially available organic binder liquid may be used. Commercially available organic binder liquids can be used as they are or diluted with water or the like. The organic binder liquid may contain an inorganic binder. Examples of the dispersion medium for the organic binder include anionic surfactants, nonionic surfactants, and cationic surfactants. From the viewpoint of long-term stability of the latex, these dispersion media may be added as appropriate when preparing the binder liquid.

In the case of an inorganic binder, a sol, colloid, slurry, or solution containing the inorganic binder can be used as the binder liquid. The inorganic binder liquid may contain an organic binder. Moreover, a dispersion stabilizer may be added to the inorganic binder liquid in order to improve the stability of the inorganic binder. Examples of the dispersion stabilizer include acetic acid, lactic acid, hydrochloric acid, and nitric acid.

The binder concentration in the binder liquid is appropriately adjusted depending on the supply amount of the binder liquid, the binder content in the target binder-containing inorganic fiber molded article, the type of binder, the method of impregnating the binder liquid, and the like. The binder concentration in the binder liquid can be, for example, within a range of 0.5% by mass or more and 50% by mass or less. If the binder concentration is too low, the binder will be unevenly distributed in the binder-containing inorganic fiber molded article, and the amount of fiber scattering may not be sufficiently suppressed. Furthermore, if the binder concentration is too high, it may become difficult for the binder liquid to impregnate the inorganic fiber molded body.

The method for impregnating the inorganic fiber molded body with the binder liquid is not particularly limited as long as it is a method that can uniformly impregnate the inorganic fiber molded body with the binder liquid. Examples include a method of applying a binder solution, and a method of injecting a binder liquid into an inorganic fiber molded article.

The method of applying the binder liquid to the inorganic fiber molded body is not particularly limited as long as it is a method that can uniformly apply the binder liquid to the inorganic fiber molded body, and examples thereof include a spray method, a roll coating method, Examples include a curtain coating method, a kiss coating method, a gravure coating method, a die coating method, and a dipping method. Further, in the case of the dipping method, the entire inorganic fiber molded body may be immersed in the binder liquid, or a part of the inorganic fiber molded body may be immersed in the binder liquid. In addition, when a part of the inorganic fiber molded body is immersed in the binder liquid, for example, a predetermined amount of the binder liquid is put into a container etc., a part of the surface or end surface of the inorganic fiber molded body is brought into contact with the binder liquid, and the binder liquid is immersed. By absorbing the entire amount of binder liquid into the inorganic fiber molded body, it is possible to increase the amount of binder liquid supplied.

Furthermore, in the method of injecting the binder liquid into the inorganic fiber molded body, for example, an injector such as a syringe, pipette, or dropper can be used. Injection of the binder liquid may be repeated multiple times.

Among them, the method of impregnating the inorganic fiber molded body with a binder liquid is a method of applying a binder liquid to the inorganic fiber molded body, and is a method other than the dipping method, or a method of impregnating a part of the inorganic fiber molded body with a binder liquid. It is preferable to use a method of immersing the inorganic fiber molded article in water or a method of injecting a binder liquid into the inorganic fiber molded article. In the case of coating methods other than the dipping method, partial dipping method, and injection method, the amount of binder liquid supplied is generally relatively small. In this case, it is difficult to impregnate the entire inorganic fiber molded body with the binder liquid. In contrast, in this embodiment, in the case of a coating method other than the dipping method, a partial dipping method, or an injection method, by increasing the amount of binder liquid supplied, the binder liquid is applied to the entire inorganic fiber molded article. Can be impregnated.

Furthermore, in the case of the coating method, the binder liquid may be applied to one side or both sides of the inorganic fiber molded body. In the case of double-sided coating, by increasing the amount of binder liquid supplied, it is possible to impregnate the inside of the inorganic fiber molded body with the binder liquid. Furthermore, even in the case of single-sided coating, by increasing the amount of binder liquid supplied, it is possible to impregnate the inside of the inorganic fiber molded body with the binder liquid. Furthermore, in the case of single-sided coating, for example, in the liquid removal step described below, the binder liquid of the inorganic fiber molded body is suctioned from the side opposite to the side on which the binder liquid is applied. The binder liquid can be moved from the coated surface to the opposite surface, and the entire inorganic fiber molded article can be impregnated with the binder liquid.

Furthermore, in the case of the coating method, the binder liquid may be applied not only to the surface of the inorganic fiber molded product but also to the end face of the inorganic fiber molded product. In a binder-containing inorganic fiber molded product, the end face is more damaged than the surface due to processing such as cutting, so by applying a binder liquid to the end face of the inorganic fiber molded product, fiber scattering can be effectively suppressed. The amount of dust generated can be further reduced.

In the case of the injection method, for example, the binder liquid may be injected from one side of the inorganic fiber molded body, or the binder liquid may be injected from both sides of the inorganic fiber molded body. Among these, double-sided injection is preferred. In the case of double-sided injection, there is no need to penetrate the injector deeply compared to the case of single-sided injection, so damage to the inorganic fiber molded body can be reduced. On the other hand, even in the case of single-sided injection, by increasing the amount of binder liquid supplied, it is not necessary to penetrate the injector deeply, and a predetermined amount of binder liquid can be impregnated.

In the case of the injection method, the binder liquid may be injected not only near the surface or the center of the inorganic fiber molded product but also near the end face of the inorganic fiber molded product. In a binder-containing inorganic fiber molded product, the end face is more damaged than the surface due to processing such as cutting, so by injecting a binder liquid near the end face of the inorganic fiber molded product, fiber scattering can be effectively suppressed. , the amount of dust generated can be further reduced.

In this embodiment, when cutting the inorganic fiber molded body, an impregnation process may be performed before the cutting process, or an impregnation process may be performed after the cutting process.

2. Drying process In this embodiment, a drying process of drying the inorganic fiber molded body impregnated with the binder liquid is usually performed after the above-mentioned impregnation process.

The drying method is not particularly limited as long as it can remove the solvent and dispersion medium contained in the binder liquid, and examples include natural drying, compression drying, ventilation drying, hot air drying, blow drying, heat drying, reduced pressure drying, and centrifugation. Examples include drying and suction drying.

The drying temperature is appropriately selected depending on the drying method, the type of binder, and the like. The drying temperature may be at least the boiling point of the solvent or dispersion medium contained in the binder liquid. Among these, in the case of an organic binder, the drying temperature is preferably higher than the temperature at which the crosslinking reaction of the organic binder starts and progresses and lower than the decomposition temperature of the organic binder. Specifically, the drying temperature is preferably within the range of 80°C or higher and 200°C or lower, and more preferably within the range of 120°C or higher and 160°C or lower. If the drying temperature is too low, there is a risk that sufficient drying may not be possible or that crosslinking of the binder may be insufficient. On the other hand, if the drying temperature is too high, the binder may change in quality, the solvent or dispersion medium of the binder liquid may rapidly evaporate, and migration of the binder may occur.

Other drying conditions, such as air volume during drying and drying time, are adjusted as appropriate so that the solvent and dispersion medium can be removed from the inorganic fiber molded article impregnated with the binder liquid, and the binder is not removed. . The drying time can be, for example, about 10 seconds to about several tens of minutes.

Moreover, when an inorganic binder is used, baking is usually performed after drying. The firing conditions can be appropriately selected from general firing conditions in the manufacturing method of a binder-containing inorganic fiber molded body containing an inorganic binder.

3. De-liquid process In this embodiment, a de-liquid process of removing the binder liquid from the inorganic fiber molded body impregnated with the binder liquid may be performed between the above-mentioned impregnation process and drying process. In the drying process described later, the solvent and dispersion medium of the binder liquid can be easily removed, and the drying time can be shortened.

Examples of the liquid removal method include centrifugal liquid removal, compression liquid removal, suction liquid removal, and the like. In the case of suction removal, it is preferable to suction the binder liquid from the surface of the inorganic fiber molded body opposite to the binder liquid supply surface. The binder liquid can be moved from the binder liquid applied surface of the inorganic fiber molded article to the opposite surface thereof, and the entire inorganic fiber molded article can be impregnated with the binder liquid.

Deliquing conditions such as pressure and deliquing time during delitting are adjusted as appropriate so that the entire amount of binder in the binder liquid is not removed.

II. Second embodiment of the method for producing a binder-containing inorganic fiber molded article The method for producing a binder-containing inorganic fiber molded article of this embodiment includes an impregnation step of impregnating an inorganic fiber molded article with a binder solution containing a binder. A method for producing an inorganic fiber molded article, wherein the bulk density of the inorganic fiber molded article when free is 0.10 g/cm ³ or more and 0.20 g/cm ³ or less, and the content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less based on 100 parts by mass of the fiber molded body, and the amount of the binder liquid supplied in the impregnation step is 100% by volume of the inorganic fiber molded body, Provided is a method for producing an inorganic fiber molded article containing a binder in a binder content of 5% by volume or more.

In this embodiment, an inorganic fiber molded article having a high bulk density and a high basis weight is used. Even in such a case, the entire inorganic fiber molded body can be impregnated with the binder liquid by relatively increasing the amount of the binder liquid supplied in the impregnation step. Therefore, even when the binder content in the binder-containing inorganic fiber molded article is relatively small, fiber scattering can be suppressed. Therefore, when using an inorganic fiber molded article having a high bulk density and a high basis weight, it is possible to reduce the amount of dust generated while reducing the content of the binder. That is, in the case of an inorganic fiber molded article having a high bulk density and a high basis weight, it is possible to achieve both a low binder amount and low dust generation.

Each step of the method for producing a binder-containing inorganic fiber molded article according to this embodiment can be the same as the method for producing a binder-containing inorganic fiber molded article according to the first embodiment, so the explanation here is omitted. do.

Moreover, since the inorganic fiber molded article is the same as the inorganic fiber molded article described in the above section "A. Inorganic fiber molded article II. Second embodiment", a description thereof will be omitted here.

Note that the present invention is not limited to the above embodiments. The above-mentioned embodiments are illustrative, and any embodiment that has substantially the same configuration as the technical idea stated in the claims of the present invention and has similar effects is the present invention. within the technical scope of the invention.

EXAMPLES The present invention will be explained in further detail by showing Examples and Comparative Examples below.

[Example 1]
An alumina fiber needle blanket with a basis weight of 2800 g/m ² was used as the inorganic fiber molded body. Further, an acrylic binder liquid diluted with water so that the binder content with respect to the inorganic fiber molded body was 1 part by mass (target value) and the same volume as the needle blanket was applied to the needle blanket by a spray method. Thereafter, it was dehydrated using a centrifugal dehydrator and dried for 20 minutes in a blow dryer at 135°C. Thereby, a binder-containing inorganic fiber molded article was obtained.

[Example 2]
An alumina fiber needle blanket with a basis weight of 2800 g/m ² was used as the inorganic fiber molded body. Pour the same volume of acrylic binder liquid as the needle blanket into a container, diluted with water so that the binder content for the inorganic fiber molded body is 0.3 parts by mass (target value), and place the needle on top of the acrylic binder liquid. A blanket was placed and a portion of the needle blanket was dipped into the acrylic binder solution. Thereafter, it was dehydrated using a centrifugal dehydrator and dried for 20 minutes in a blow dryer at 135°C. Thereby, a binder-containing inorganic fiber molded article was obtained.

[Example 3]
A binder-containing inorganic fiber molded body was produced in the same manner as in Example 1, except that an alumina fiber needle blanket with a basis weight of 3200 g/m ² was used as the inorganic fiber molded body.

[Example 4]
An alumina fiber needle blanket with a basis weight of 3200 g/m ² was used as the inorganic fiber molded body, and the binder content with respect to the inorganic fiber molded body was diluted with water to be 1 part by mass (target value). A binder-containing inorganic fiber molded article was produced in the same manner as in Example 2, except that a portion of the needle blanket was immersed in an acrylic binder liquid containing 10% by volume of the needle blanket.

[Example 5]
An alumina fiber needle blanket with a basis weight of 5600 g/m ² was used as the inorganic fiber molded body, and the binder content was diluted with water to be 1 part by mass (target value) with respect to the inorganic fiber molded body. A binder-containing inorganic fiber molded article was produced in the same manner as in Example 1, except that 10% by volume of the acrylic binder liquid was applied to the needle blanket.

[Example 6]
An alumina fiber needle blanket with a basis weight of 6400 g/m ² was used as the inorganic fiber molded body, and the binder content was diluted with water to be 0.3 parts by mass (target value) with respect to the inorganic fiber molded body. A binder-containing inorganic fiber molded article was produced in the same manner as in Example 1, except that 10% by volume of the acrylic binder liquid was applied to the needle blanket and that centrifugal dehydration was not performed.

[Example 7]
Same as Example 1 except that 50% by volume of the acrylic binder liquid was diluted with water so that the binder content with respect to the inorganic fiber molded body was 1 part by mass (target value) and applied to the needle blanket. A binder-containing inorganic fiber molded article was prepared.

[Example 8]
An alumina fiber needle blanket with a basis weight of 3200 g/m ² was used as the inorganic fiber molded body, and the binder content with respect to the inorganic fiber molded body was diluted with water to be 1 part by mass (target value). A binder-containing inorganic fiber molded body was produced in the same manner as in Example 1, except that 50% by volume of the acrylic binder liquid was applied to the needle blanket.

[Example 9]
An alumina fiber needle blanket with a basis weight of 3200 g/m ² was used as the inorganic fiber molded body, and the binder content with respect to the inorganic fiber molded body was diluted with water to be 1 part by mass (target value). A binder-containing inorganic fiber molded article was produced in the same manner as in Example 2, except that a portion of the needle blanket was immersed in an acrylic binder liquid containing 50% by volume of the needle blanket.

[Example 10]
Same as Example 1 except that 10% by volume of the acrylic binder liquid was diluted with water so that the binder content with respect to the inorganic fiber molded body was 1 part by mass (target value) and applied to the needle blanket. A binder-containing inorganic fiber molded article was prepared.

[Example 11]
An alumina fiber needle blanket with a basis weight of 3200 g/m ² was used as the inorganic fiber molded body, and the binder content with respect to the inorganic fiber molded body was diluted with water to be 1 part by mass (target value). A binder-containing inorganic fiber molded article was produced in the same manner as in Example 1, except that 10% by volume of the acrylic binder liquid was applied to the needle blanket.

[Example 12]
The acrylic binder liquid was diluted with water so that the binder content with respect to the inorganic fiber molded body was 1 part by mass (target value), and 5% by volume of acrylic binder liquid was applied to the needle blanket, and centrifugal dehydration was not performed. A binder-containing inorganic fiber molded body was produced in the same manner as in Example 1 except for the above.

[Example 13]
An alumina fiber needle blanket with a basis weight of 3200 g/m ² was used as the inorganic fiber molded body, and the needle blanket was diluted with water so that the binder content with respect to the inorganic fiber molded body was 1 part by mass (target value). A binder-containing inorganic fiber molded article was produced in the same manner as in Example 1, except that 5% by volume of the acrylic binder liquid was applied and that centrifugal dehydration was not performed.

[Example 14]
Same as Example 1 except that 300% by volume of acrylic binder liquid was applied to the needle blanket, diluted with water so that the binder content with respect to the inorganic fiber molded body was 1 part by mass (target value). A binder-containing inorganic fiber molded article was prepared.

[Example 15]
An alumina fiber needle blanket with a basis weight of 3200 g/m ² was used as the inorganic fiber molded body, and the binder content with respect to the inorganic fiber molded body was diluted with water to be 1 part by mass (target value). A binder-containing inorganic fiber molded article was produced in the same manner as in Example 1, except that 280% by volume of the acrylic binder liquid was applied to the needle blanket.

[Comparative example 1]
The acrylic binder liquid was diluted with water so that the binder content with respect to the inorganic fiber molded body was 1 part by mass (target value), and 1% by volume of acrylic binder liquid was applied to the needle blanket, and centrifugal dehydration was not performed. A binder-containing inorganic fiber molded body was produced in the same manner as in Example 1 except for the above.

[Comparative example 2]
The acrylic binder liquid was diluted with water so that the content of the binder in the inorganic fiber molded body was 1 part by mass (target value), and 2% by volume of the acrylic binder liquid was applied to the needle blanket, and centrifugal dehydration was not performed. A binder-containing inorganic fiber molded body was produced in the same manner as in Example 1 except for the above.

[Comparative example 3]
A binder-containing inorganic fiber molded body was produced in the same manner as in Comparative Example 1, except that an alumina fiber needle blanket with a basis weight of 3200 g/m ² was used as the inorganic fiber molded body.

[Comparative example 4]
The acrylic binder liquid was diluted with water so that the content of the binder in the inorganic fiber molded body was 2.5 parts by mass (target value), and 1% by volume of the acrylic binder liquid was applied to the needle blanket, and centrifugal dehydration was performed. A binder-containing inorganic fiber molded article was produced in the same manner as in Example 1, except that this was not carried out.

[Comparative example 5]
A part of an alumina fiber needle blanket with a basis weight of 2800 g/m ² was immersed in water, dehydrated using a centrifugal dehydrator, and dried for 20 minutes in a blow dryer at 135°C.

[Comparative example 6]
A part of an alumina fiber needle blanket with a basis weight of 3200 g/m ² was immersed in water, dehydrated using a centrifugal dehydrator, and dried for 20 minutes in a blow dryer at 135°C.

[Evaluation 1]
(Weight loss rate of binder-containing inorganic fiber molded article before and after shaking test)
As described in the above section "A. Binder-Containing Inorganic Fiber Molded I. First Embodiment 3. Shaking Test", a shaking test was conducted, and the weight of the binder-containing inorganic fiber molded object before and after the shaking test was The reduction rate was calculated.

(Binder content)
As described in the above section "A. Binder-Containing Inorganic Fiber Molded I. First Embodiment 2. Binder", the binder content ( parts by mass) were determined.

From Table 1, when using a high basis weight inorganic fiber molded product, even if the binder content in the binder-containing inorganic fiber molded product is small, the weight loss rate before and after the shaking test is 1% or less. It was confirmed that fiber scattering can be suppressed. Furthermore, as in Comparative Examples 1 and 2, it was found that with the conventional binder liquid impregnation method, the weight loss rate before and after the shaking test was large, and fiber scattering could not be suppressed. In addition, from Comparative Examples 3 and 4, when using a high basis weight inorganic fiber molded article, when applying the conventional binder liquid impregnation method, in order to suppress fiber scattering, the binder-containing inorganic fiber molded article It was found that it was necessary to increase the content of binder in. Further, from Comparative Examples 5 and 6, it was found that simply washing the inorganic fiber molded body with water and removing weakly entangled fine fibers that could become dust could not suppress fiber scattering.

[Example 16]
An alumina fiber needle blanket with a basis weight of 2800 g/m ² was used as the inorganic fiber molded body. Further, an acrylic binder liquid diluted with water so that the binder content with respect to the inorganic fiber molded body was 1 part by mass (target value) and the same volume as the needle blanket was applied to the needle blanket by a spray method. Thereafter, it was dehydrated using a centrifugal dehydrator and dried for 20 minutes in a blow dryer at 135°C. Thereby, a binder-containing inorganic fiber molded article was obtained.

[Example 17]
A binder-containing inorganic fiber molded body was produced in the same manner as in Example 16, except that an alumina fiber needle blanket with a basis weight of 3200 g/m ² was used as the inorganic fiber molded body.

[Comparative Example 7]
The acrylic binder liquid was diluted with water so that the binder content with respect to the inorganic fiber molded body was 1 part by mass (target value), and 1% by volume of acrylic binder liquid was applied to the needle blanket, and centrifugal dehydration was not performed. A binder-containing inorganic fiber molded body was produced in the same manner as in Example 16 except for the above.

[Comparative example 8]
A binder-containing inorganic fiber molded body was produced in the same manner as in Comparative Example 7, except that an alumina fiber needle blanket with a basis weight of 3200 g/m ² was used as the inorganic fiber molded body.

[Evaluation 2]
(Weight loss rate of binder-containing inorganic fiber molded article before and after shaking test)
As described in the above section "A. Binder-Containing Inorganic Fiber Molded I. First Embodiment 3. Shaking Test", a shaking test was conducted, and the weight of the binder-containing inorganic fiber molded object before and after the shaking test was The reduction rate was calculated.

(Binder content)
As described in the above section "A. Binder-Containing Inorganic Fiber Molded I. First Embodiment 2. Binder", the binder content ( parts by mass) were determined.

(Binder content in the first region, second region, and third region)
As described in the above section "A. Binder-containing inorganic fiber molded article I. First embodiment 2. Binder", the binder-containing inorganic fiber molded article is divided into three equal parts in the thickness direction, and the binder-containing inorganic fiber molded article is divided into three equal parts in the thickness direction. When considering the first region, the second region, and the third region from one side of the body, the content (parts by mass) of the binder in each region relative to 100 parts by mass of the inorganic fibers was determined. The table below shows the binder content in the area showing the maximum binder content among the three areas.

In Comparative Examples 7 and 8, the maximum value of the binder content in each region was more than twice the target value of 1 part by mass for the binder content, indicating that the binder was unevenly distributed. Ta. In the case of using a high basis weight inorganic fiber molded article, if the binder is unevenly distributed, the weight loss rate before and after the shaking test is large, suggesting that fiber scattering cannot be suppressed. On the other hand, in Examples 16 and 17, compared to Comparative Examples 7 and 8, the difference between the binder content of the binder-containing inorganic fiber molded body and the maximum value of the binder content of each region was small, and the binder was unevenly distributed. was decreasing. This suggests that when using an inorganic fiber molded article with a high basis weight, dust generation can be reduced by reducing the uneven distribution of the binder.

1... Binder-containing inorganic fiber molded article

Claims (12)

A binder-containing inorganic fiber molded article, the inorganic fiber molded article containing a binder,
The basis weight of the inorganic fiber molded article is more than 2600 g/m ² ,
The content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less with respect to 100 parts by mass of the inorganic fiber molded body,
The 50 mm square binder-containing inorganic fiber molded article was placed in a sieve with an opening of 4 mm, and the sieve was shaken vertically in a reciprocating manner, with an amplitude of 2 mm, a shaking speed of 3000 reciprocations/min, and a vibration time of 10 minutes. When a shaking test is performed, the weight loss rate of the binder-containing inorganic fiber molded article before and after the shaking test is 1.0% or less,
A binder-containing inorganic fiber molded article, wherein the binder contains only an organic binder . A binder-containing inorganic fiber molded article, the inorganic fiber molded article containing a binder,
The bulk density of the inorganic fiber molded article when free is 0.10 g/cm ³ or more and 0.20 g/cm ³ or less,
The content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less with respect to 100 parts by mass of the inorganic fiber molded body,
The 50 mm square binder-containing inorganic fiber molded article was placed in a sieve with an opening of 4 mm, and the sieve was shaken vertically in a reciprocating manner, with an amplitude of 2 mm, a shaking speed of 3000 reciprocations/min, and a vibration time of 10 minutes. When a shaking test is performed, the weight loss rate of the binder-containing inorganic fiber molded article before and after the shaking test is 1.0% or less,
A binder-containing inorganic fiber molded article, wherein the binder contains only an organic binder . A binder-containing inorganic fiber molded article, the inorganic fiber molded article containing a binder,
The basis weight of the inorganic fiber molded article is more than 2600 g/m ² ,
When the binder-containing inorganic fiber molded body is divided into three equal parts in the thickness direction, and the binder-containing inorganic fiber molded body is divided into a first region, a second region, and a third region from one side of the binder-containing inorganic fiber molded body, each region contains: The maximum value of the content of the binder in each region is 2.24 parts by mass or less with respect to 100 parts by mass of the inorganic fibers,
The 50 mm square binder-containing inorganic fiber molded article was placed in a sieve with an opening of 4 mm, and the sieve was shaken vertically in a reciprocating manner, with an amplitude of 2 mm, a shaking speed of 3000 reciprocations/min, and a vibration time of 10 minutes. When a shaking test is performed, the weight loss rate of the binder-containing inorganic fiber molded article before and after the shaking test is 1.0% or less,
A binder-containing inorganic fiber molded article, wherein the binder contains only an organic binder . A binder-containing inorganic fiber molded article, the inorganic fiber molded article containing a binder,
The bulk density of the inorganic fiber molded article when free is 0.10 g/cm ³ or more and 0.20 g/cm ³ or less,
When the binder-containing inorganic fiber molded body is divided into three equal parts in the thickness direction, and the binder-containing inorganic fiber molded body is divided into a first region, a second region, and a third region from one side of the binder-containing inorganic fiber molded body, each region contains: The maximum content of the binder in each region is 0.01 parts by mass or more and 2.24 parts by mass or less with respect to 100 parts by mass of the inorganic fibers,
The 50 mm square binder-containing inorganic fiber molded article was placed in a sieve with an opening of 4 mm, and the sieve was shaken vertically in a reciprocating manner, with an amplitude of 2 mm, a shaking speed of 3000 reciprocations/min, and a vibration time of 10 minutes. When a shaking test is performed, the weight loss rate of the binder-containing inorganic fiber molded article before and after the shaking test is 1.0% or less,
A binder-containing inorganic fiber molded article, wherein the binder contains only an organic binder . When the binder-containing inorganic fiber molded body is divided into three equal parts in the thickness direction, and the binder-containing inorganic fiber molded body is divided into a first region, a second region, and a third region from one side of the binder-containing inorganic fiber molded body, each region contains: The binder according to claim 1 or 2, wherein the maximum content of the binder in each region is 0.01 parts by mass or more and 2.24 parts by mass or less with respect to 100 parts by mass of inorganic fibers. Containing inorganic fiber molded article. The difference between the binder content of the binder-containing inorganic fiber molded body and the maximum value of the binder content of each region is 0.75 parts by mass or less. 5. The binder-containing inorganic fiber molded article according to any one of claims 5 to 5. The binder-containing inorganic fiber molded article according to any one of claims 1 to 6 , wherein the inorganic fiber molded article contains alumina fibers. The binder-containing inorganic fiber molded article according to any one of claims 1 to 7 , wherein the inorganic fiber molded article is a needle blanket. A holding material for an exhaust gas purification device, comprising the binder-containing inorganic fiber molded article according to any one of claims 1 to 8 . A method for producing a binder-containing inorganic fiber molded body, comprising an impregnation step of impregnating an inorganic fiber molded body with a binder liquid containing a binder,
The basis weight of the inorganic fiber molded article is more than 2600 g/m ² ,
The content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less with respect to 100 parts by mass of the inorganic fiber molded body,
the binder contains only an organic binder,
A method for manufacturing a binder-containing inorganic fiber molded article, wherein the amount of the binder liquid supplied in the impregnation step is 5% by volume or more based on 100% by volume of the inorganic fiber molded article. A method for producing a binder-containing inorganic fiber molded body, comprising an impregnation step of impregnating an inorganic fiber molded body with a binder liquid containing a binder,
The bulk density of the inorganic fiber molded article when free is 0.10 g/cm ³ or more and 0.20 g/cm ³ or less,
The content of the binder is 0.01 parts by mass or more and 2.24 parts by mass or less with respect to 100 parts by mass of the inorganic fiber molded body,
the binder contains only an organic binder,
A method for manufacturing a binder-containing inorganic fiber molded article, wherein the amount of the binder liquid supplied in the impregnation step is 5% by volume or more based on 100% by volume of the inorganic fiber molded article. The method of impregnating the inorganic fiber molded body with the binder liquid is a method of applying the binder liquid to the inorganic fiber molded body, and is a method other than a dipping method, or a method of impregnating a part of the inorganic fiber molded body with the binder liquid The method for producing a binder-containing inorganic fiber molded article according to claim 10 or 11 , which is a method of immersing the inorganic fiber molded article in the binder liquid, or a method of injecting the binder liquid into the inorganic fiber molded article.

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