JP2014228035A - Fireproof heat insulation material and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fireproof heat insulation material that comprises a ceramic fiber and an inorganic binder (binding material), further can contain organic polymer coagulant, eliminates dusting and a phenomena that particles are removed from a surface, has a small thermal shrinkage factor, greatly reduces a thermal conductivity, and is extremely excellent in heat insulation performance.SOLUTION: As a ceramic fiber, a fiber whose average fiber diameter is 1.5-5 μm, and total amount of non-fibrous particles (shot) contained in a ceramic fiber is 20 wt.% or less with respect to the whole fiber, and which is subjected to heat treatment at 800-1300°C in advance is used. A fireproof heat insulation material has a thermal conductivity at 600°C of 0.060-0.090 W/(m K), a bulk density after drying of 250-400 kg/m, and a flexural strength of 0.4 MPa or more, and further a fireproof heat insulation material containing organic polymer coagulant has a bulk density after drying of 150-300 kg/m, and a flexural strength after drying of 0.6 MPa or more.

Description

  TECHNICAL FIELD The present invention relates to a refractory heat insulating material mainly used for a furnace inner surface of a heat treatment furnace, and more particularly to an inorganic fibrous refractory heat insulating material by a papermaking method and a manufacturing method thereof.

  As a refractory heat insulating material used in medium and high temperature ranges such as industrial heat treatment furnaces, it is manufactured by wet forming using a papermaking method, and is mainly composed of inorganic fibers and inorganic powders combined with an inorganic binder. Is generally widely used. In particular, a refractory heat insulating material having improved heat insulating performance by adding inorganic powder as a heat radiation scattering material to an inorganic fiber and an inorganic binder is also known.

  For example, in Patent Document 1, dehydration molding is performed by adding inorganic particles such as titanium oxide to a slurry in which inorganic fibers such as silica alumina fibers are dispersed in water, and further adding an inorganic binder and a flocculant such as silica sol. An inorganic fibrous heat insulating material produced by this method is described. In particular, since titanium oxide has a function of scattering thermal radiation, it is said that the radiation heat is scattered by containing it in the heat insulating material, and the heat insulating performance can be improved. However, its thermal conductivity at 600 ° C. exceeds 0.09 W / (m · K), which is not a satisfactory heat insulating performance.

  Further, it is known that the conventional inorganic fiber refractory heat insulating material contracts due to the crystallization of inorganic fibers when exposed to high temperatures, and the contraction increases as the heating temperature increases. Therefore, the refractory heat insulating material used for the furnace inner surface of the heat treatment furnace shrinks during the heat treatment, and a gap is generated between the refractory heat insulating materials. The gap between the refractory heat insulating materials is gradually increased by repeated heating, and there is a problem that not only the heat insulation efficiency of the furnace is lowered but also the life of the furnace body is shortened.

On the other hand, in Patent Document 2, as a microporous heat insulating material whose thermal conductivity at 600 ° C. is less than 0.09 W / (m · K), B ₂ O ₃ is not contained, and expanded vermiculite is 30 to 70 weights. %, Inorganic binder 15 to 40% by weight, infrared opaque agent 0 to 20% by weight, microporous material 15 to 50% by weight, alkali metal oxide up to 2% by weight with respect to the weight of glass reinforcing fiber A heat-insulated molded body having 0.5 to 8% by weight of glass reinforcing fibers is described.

  The microporous heat insulating material has an excellent heat insulating performance which has not been obtained conventionally, but has problems such as low strength, easy generation of dust, and poor workability and workability. As a technique to compensate for this problem, for example, Patent Document 3 describes a method of covering a microporous heat insulating material with an inorganic fiber sheath. However, this method is difficult to process, and causes an increase in the cost of the heat insulating material.

JP 2012-144031 A Japanese Patent No. 3328295 JP 2012-149658 A

  As described above, the conventional fire-resistant heat insulating material used in the middle and high temperature range has a structure in which inorganic fibers and inorganic powder are mainly bonded with an inorganic binder, and heat radiation like titanium oxide powder is used to improve heat insulating performance. It is also known to add scattering material. However, since its thermal conductivity at 600 ° C. exceeds 0.09 W / (m · K), further significant improvement in heat insulation performance is desired. In addition, conventional refractory insulation shrinks when exposed to high temperatures, so when used on the furnace inner surface of a heat treatment furnace, a gap is created between the refractory insulation due to shrinkage, which gradually increases the insulation efficiency of the furnace. There was a problem of reducing the life of the furnace body.

  Furthermore, in the conventional inorganic fibrous refractory insulation material containing inorganic powder, fine particles and fine powder derived from inorganic powder and non-fibrous particles (spherical particles that could not be made into fibers; also called shots) are separated ( Causes fine powder adhering to the surface or scattering of adhering fine powder: mainly derived from inorganic powder) or borofuri (phenomenon that particles are detached from the surface: mainly derived from non-fibrous particles) When used as a furnace wall material on the inner surface of the heat treatment furnace, there is a disadvantage that it adheres to the object to be fired.

  On the other hand, the microporous heat insulating material has an excellent heat insulating performance that has not been obtained before, but has problems such as low strength, much powdering, poor workability, and poor workability. . Therefore, the microporous heat insulating material could not be used for applications that require strength, such as a furnace wall material on the inner surface of the heat treatment furnace.

  The present invention has been made in view of the problems of the above-described conventional inorganic fiber refractory heat insulating materials and microporous heat insulating materials, and has been made refractory heat insulating materials comprising inorganic fibers and inorganic binders that have been widely used in the past. Compared to refractory materials and refractory insulation materials with titanium oxide added to scatter heat radiation, the thermal conductivity is greatly reduced, and the generation of gaps between refractory insulation materials due to repeated heating can be suppressed. An object of the present invention is to provide a fireproof heat insulating material that is excellent in workability and workability, has no dusting and no battering, has high strength, and has excellent heat insulating performance comparable to that of a microporous heat insulating material.

In order to achieve the above object, the first refractory heat insulating material provided by the present invention is composed of a ceramic fiber and an inorganic binder (binding material), and the ceramic fiber is previously heat-treated at a temperature of 800 to 1300 ° C. The ceramic fiber has an average fiber diameter of 1.5 to 5 μm and the total amount of non-fibrous particles contained in the ceramic fiber is 20% by weight or less of the whole fiber, and the thermal conductivity at 600 ° C. is 0.5. 060 to 0.090 W / (m · K), the bulk density after drying is 250 to 400 kg / m ³ , and the bending strength after drying is 0.4 MPa or more.

The second refractory heat insulating material provided by the present invention is composed of ceramic fibers, an inorganic binder (binding material), and an organic polymer flocculant, and the ceramic fibers are preheated at a temperature of 800 to 1300 ° C. The average fiber diameter of the ceramic fibers is 1.5 to 5 μm, and the total amount of non-fibrous particles contained in the ceramic fibers is 20% by weight or less of the whole fibers, and the thermal conductivity at 600 ° C. is 0. 0.060 to 0.090 W / (m · K), the bulk density after drying is 150 to 300 kg / m ³ , and the bending strength after drying is 0.6 MPa or more.

  The first refractory heat insulating material according to the present invention preferably contains 70 to 85% by weight of ceramic fibers and 15 to 30% by weight of inorganic binder. The second refractory heat insulating material according to the present invention contains 85 to 99.5% by weight of ceramic fiber, 0.5 to 15% by weight of an inorganic binder, and 0.4 to 12% by weight of an organic polymer flocculant. It is preferable to do. Moreover, as said ceramic fiber, a silica alumina fiber, a silica alumina zirconia fiber, or a biosoluble fiber is preferable.

  Moreover, the manufacturing method of the 1st fireproof heat insulating material which this invention provides is a ceramic fiber with an average fiber diameter of 1.5-5 micrometers, and the total of non-fibrous particle | grains was made into 20 weight% or less of the whole fiber. Thereafter, the ceramic fiber is heat-treated at a temperature of 800 to 1300 ° C., then the ceramic fiber is dispersed in water, an inorganic binder (binding material) is added and mixed, and dehydration molding is performed by vacuum suction using a mold. It is characterized by.

  Further, in the second method for producing a refractory heat insulating material provided by the present invention, ceramic fibers having an average fiber diameter of 1.5 to 5 μm are classified to make the total of non-fibrous particles 20% by weight or less of the whole fibers. Thereafter, the ceramic fiber is heat-treated at a temperature of 800 to 1300 ° C., then the ceramic fiber is dispersed in water, an inorganic binder (binding material) is added and mixed, and an organic polymer flocculant is further added. It is characterized by dehydration molding by vacuum suction using a mold.

  According to the present invention, the strength and workability and workability are excellent, and the shrinkage of the refractory heat insulating material due to repeated heating can be extremely reduced. Compared to refractory insulation with an inorganic binder as the main component and refractory insulation with the addition of titanium dioxide powder as a heat radiation scattering material, the refractory insulation has a low thermal conductivity and greatly improved insulation performance. Can be provided. Moreover, since the refractory heat insulating material of the present invention does not contain inorganic powder, there is no dusting or battering and excellent spalling resistance.

  Therefore, the refractory heat insulating material of the present invention has extremely low thermal conductivity, is excellent in workability and workability, has no dusting and boro-free, and does not contaminate the fired product when used on the furnace inner surface of a heat treatment furnace. In addition, since the generation of gaps between refractory insulation materials due to repeated heating can be suppressed, the heat insulation efficiency of the furnace is prevented from being lowered, the thermal load of the backlining is reduced, and the life of the furnace body is improved. Since it can be improved, it is very excellent as a low thermal conductive board used on the furnace inner surface of the heat treatment furnace.

  In the present invention, the first refractory heat insulating material comprises ceramic fibers having an average fiber diameter of 1.5 to 5 μm and an inorganic binder (binding material), and the second refractory heat insulating material has an average fiber diameter of 1.5 to 5 μm. These ceramic fibers, an inorganic binder (binding material), and an organic polymer flocculant do not contain inorganic powder particles such as titanium oxide powder. Moreover, the ceramic fibers usually contain 50 to 60% by weight of non-fibrous particles (shots) produced in the fiber production process, but the ceramic fibers used in the present invention have a total of 20 non-fibrous particles in advance. Reduced to less than wt%. In addition, the fiber diameter of the ceramic fiber was measured using SEM (scanning electron microscope), and the average value of 250 to 300 fibers was defined as the average fiber diameter.

  The use of ceramic fibers having an average fiber diameter of 1.5 to 5 μm and a non-fibrous particle content reduced to 20% by weight or less can greatly contribute to the improvement of the heat insulation performance of the refractory heat insulating material. It was confirmed. That is, 90% or more of the non-fibrous particles contained in the ceramic fiber in an amount of 50 to 60% by weight are 45 μm or more. When a large amount of non-fibrous particles having a large particle size exists in this manner, large pores are likely to be generated in the heat insulating material, and heat transfer by gas convection and heat transfer by collision of gas molecules are promoted. As a result, in the conventional heat insulating material containing a large amount of non-fibrous particles, satisfactory heat insulating performance could not be obtained even if the titanium oxide powder was contained for the purpose of scattering thermal radiation.

  On the other hand, the average fiber diameter of ceramic fibers is generally much smaller than the particle diameter of the non-fibrous particles. Therefore, in order to reduce the pores in the refractory insulation and suppress heat transfer due to gas convection and gas molecule collision, the amount of non-fibrous particles contained in the ceramic fiber is reduced. It is effective to increase the proportion of ceramic fibers having a small average fiber diameter.

  Based on the above findings, the present inventors removed the non-fibrous particles contained in the ceramic fiber as much as possible, and by increasing the proportion of the ceramic fiber relatively, the specific surface area increased, the heat reflection effect It was confirmed that the thermal conductivity was greatly reduced and greatly contributed to the improvement of the heat insulating performance of the heat insulating material. The average fiber diameter of the ceramic fibers is set to 1.5 to 5 μm. If the average fiber diameter exceeds 5 μm, the thermal conductivity of the refractory heat insulating material increases. Conversely, if it is less than 1.5 μm, the bending strength decreases. This is because it easily breaks when added to water together with an inorganic binder and stirred.

  The total amount of non-fibrous particles contained in the ceramic fiber is 20% by weight or less of the entire ceramic fiber to be used. When the total amount of non-fibrous particles exceeds 20% by weight of the entire ceramic fiber, the effect of improving the heat insulating performance of the refractory heat insulating material becomes insufficient. It is desirable to remove non-fibrous particles contained in the ceramic fiber as much as possible, but it is preferable to make it 5% by weight or more in order to suppress an increase in processing cost, and 15% by weight or less considering the effect. Is preferred. In addition, content of the non-fibrous particle | grains (shot) in a ceramic fiber can be measured based on 10 (Determining of shot) of ISO10635.

  As a method for removing the non-fibrous particles contained in the ceramic fibers, a method of separating the non-fibrous particles by dispersing the ceramic fibers in water is simple and preferable. That is, when the ceramic fiber is dispersed in water, the ceramic fiber floats but the non-fibrous particles settle in the water. Therefore, after the non-fibrous particles have sufficiently settled, the non-fibrous particles can be easily and efficiently removed by collecting the ceramic fibers that have floated near the water surface.

  As the ceramic fiber, silica alumina fiber, silica alumina zirconia fiber, alumina silica chromia fiber, silica alumina titania fiber, biosoluble fiber, etc. can be used. Among them, silica alumina fiber, silica alumina zirconia fiber or biosoluble fiber can be used. Can be suitably used. For example, silica alumina fibers and silica alumina zirconia fibers include Isowool (trade name) manufactured by Isolite Industry Co., Ltd. As the biosoluble fiber, Isowool BSSR (trade name) manufactured by Isolite Industry Co., Ltd., Insulfrax, Isofrax (trade name) manufactured by Unifrax Co., Ltd., and the like can be used.

  Moreover, the ceramic fiber used for the fireproof heat insulating material of this invention is heat-processed at the temperature of 800-1300 degreeC previously. By preliminarily crystallizing the ceramic fibers that make up the refractory insulation at the above temperature, even if the refractory insulation is repeatedly exposed to high temperatures, the shrinkage of the ceramic fibers and the refractory insulation is minimized. Thus, it is possible to prevent the generation of a gap between the refractory heat insulating materials adjacent to each other. Therefore, the fireproof heat insulating material of the present invention can not only prevent a decrease in the heat insulation efficiency of the furnace, but also can reduce the thermal load of the back lining and improve and improve the life of the furnace body.

  The heat treatment temperature of the ceramic fiber needs to be equal to or higher than the temperature at which the crystallization of the ceramic fiber progresses and the fiber contracts, and specifically, a desirable temperature in the range of 800 to 1300 ° C. Can be selected. For example, silica alumina fiber or silica alumina zirconia fiber is preferably heat-treated at a temperature of 900 to 1300 ° C. for 1 to 3 hours. Moreover, in the case of a biosoluble fiber, it is preferable to heat-process at a temperature of 800-1100 degreeC for 1-3 hours.

  As the inorganic binder (binding material), commonly used materials such as silica sol and alumina sol may be used. Specifically, colloidal silica manufactured by Nissan Chemical Industries, Ltd. can be preferably used as the silica sol, and colloidal alumina manufactured by Nissan Chemical Industries, Ltd. can be used as the alumina sol. The organic polymer flocculant may be a commonly used one such as starch or polyacrylamide. Specifically, starch produced by Nissho Chemical Industry Co., Ltd. and polyacrylamide include Polystron (trade name) produced by Arakawa Chemical Industries, Ltd.

  In the 1st fireproof heat insulating material of this invention, it is preferable to contain 70 to 85 weight% of ceramic fibers, and 15 to 30 weight% of inorganic binders. The second refractory heat insulating material of the present invention contains 85 to 99.5% by weight of ceramic fiber, 0.5 to 15% by weight of an inorganic binder, and 0.4 to 12% by weight of an organic polymer flocculant. It is preferable to do. As described above, in the refractory heat insulating material of the present invention, since the content of non-fibrous particles in the ceramic fiber is reduced from 50 to 60% by weight to 20% by weight or less, the ceramic fiber used (non-fibrous particles) The ceramic fiber content in the refractory insulation material can be increased from 40-50% by weight to 80% by weight or more, which has been conventionally used. As a result, the bending strength of the refractory heat insulating material is also improved.

  However, in the first refractory heat insulating material composed of 70 to 85% by weight of ceramic fiber and 15 to 30% by weight of inorganic binder, if the content of the inorganic binder is less than 15% by weight, sufficient strength cannot be obtained, and inorganic If the binder content exceeds 30%, sufficient heat insulating performance cannot be obtained. In the second refractory heat insulating material comprising 85 to 99.5% by weight of ceramic fiber, 0.5 to 15% by weight of inorganic binder, and 0.4 to 12% by weight of organic polymer flocculant, the inorganic binder If the content is less than 0.5% by weight, aggregation is insufficient, and if it exceeds 15% by weight, filtration resistance at the time of molding increases and molding becomes difficult. Further, even when the content of the organic polymer flocculant is less than 0.4% by weight, aggregation is insufficient as in the case of the inorganic binder, and when it exceeds 12% by weight, the filtration resistance at the time of molding is increased, which is not preferable.

  The production of the first refractory heat insulating material according to the present invention is carried out by using ceramic fibers having an average fiber diameter of 1.5 to 5 μm and having a non-fibrous particle content of 20% by weight or less as described above at 800 to 1300 ° C. Heat treatment at temperature. Add a predetermined amount of this ceramic fiber to water and stir to disperse the ceramic fiber. Then, add a predetermined amount of inorganic binder (binding material), stir and mix, and then dehydrate by suction using a molding die. Mold. The obtained molded body can be used as a refractory heat insulating material as it is, but is preferably further dried at 100 to 120 ° C.

  In addition, in the production of the second refractory heat insulating material according to the present invention, as described above, ceramic fibers having an average fiber diameter of 1.5 to 5 μm, in which the content of non-fibrous particles is 20% by weight or less in advance, are applied to 800 to 1300. Heat treatment is performed at a temperature of ° C. A predetermined amount of this ceramic fiber is added to water and stirred to disperse the ceramic fiber, and then a predetermined amount of an inorganic binder (binding material) is added and mixed with stirring. Next, after adding an organic polymer flocculant to form a floc, it is dehydrated and molded by suction using a molding die. The obtained molded body can be directly used as a refractory heat insulating material, but is preferably further dried at 100 to 120 ° C.

  In the first and second refractory heat insulating materials according to the present invention, the total amount of non-fibrous particles contained in the ceramic fiber used is reduced to 20% by weight or less of the entire fiber. In some cases, the desired density cannot be obtained by dehydration molding using suction. Therefore, in the production of the first and second refractory heat insulating materials according to the present invention, it is preferable to adjust the bulk density by roller pressing the dehydrated molded body.

  In addition, according to dehydration molding by suction using the molding die, the molding surface parallel to the inner surface of the die is a surface in which ceramic fibers are two-dimensionally randomly oriented. Therefore, when enforcing the fireproof heat insulating material, by arranging the fireproof heat insulating material so that the molding surface is perpendicular to the heat propagation direction, heat becomes difficult to be transmitted, and the heat insulating property can be further improved. it can.

  The refractory heat insulating material of the present invention produced in this way is composed of ceramic fibers having a non-fibrous particle content of 20% by weight or less and an inorganic binder, and does not contain inorganic powder. No dusting or battering, excellent workability and workability, excellent spalling resistance, high strength, extremely low shrinkage even when repeatedly exposed to high temperatures, and heat conduction at 600 ° C The rate is as extremely low as 0.060 to 0.090 W / (m · K), and the insulation performance is very high. Therefore, the refractory heat insulating material of the present invention is very excellent as a low heat conduction board used on the inner surface of the heat treatment furnace.

Isowool (trade name), which is a silica alumina fiber manufactured by Isolite Industry Co., Ltd., is used as the ceramic fiber, or Isowool BSSR (trade name), which is a biosoluble fiber, and Nissan Chemical Industries, Ltd. is used as the inorganic binder (binding material). Colloidal silica manufactured (SiO ₂ concentration: 40% by weight), and starch produced by Nissho Chemical Co., Ltd. as an organic polymer flocculant was used, and the following Examples 1 to 4 and Comparative Examples 1 to 3 A refractory insulation was produced.

[Example 1]
The ceramic fiber has a composition of Al ₂ O ₃ : 45% by weight or more, Al ₂ O ₃ + SiO ₂ : 98% by weight or more, an average fiber diameter of 2.3 μm, and a non-fibrous particle content of 53% by weight. Silica alumina fiber (trade name Isowool) was used. The silica-alumina fiber was thrown into water, dispersed, and allowed to stand to float the silica-alumina fiber and settle non-fibrous particles. After the non-fibrous particles have sufficiently settled, the silica alumina fibers floating near the water surface are collected to remove the non-fibrous particles and the content of the non-fibrous particles is 10.7% by weight. Alumina fibers were obtained. The content of non-fibrous particles (shot) in the silica-alumina fiber was measured according to ISO 10635 10 (Determination of shot).

  Next, the silica alumina fiber (non-fibrous particle content 10.7 wt%) was subjected to a heat treatment at 1280 ° C. for 1.5 hours. The silica alumina fiber and the inorganic binder after the heat treatment were added to water and stirred for several minutes to form a slurry containing 95% by weight ceramic fiber and 5% by weight inorganic binder. An aqueous solution of an organic polymer flocculant was added to the slurry to cause aggregation, and suction molding was performed using a mold into a plate shape of 900 mm long × 600 mm wide × 25 mm thick.

The obtained plate-like molded body was dried at 120 ° C. to produce the fireproof heat insulating material of Example 1. The bulk density of the refractory insulation after drying was 190 kg / m ³ . The dried refractory insulation is analyzed for chemical components by JIS R2216 (fluorescence X-ray fluorescence analysis method for refractory products), thermal conductivity (600 ° C.), three-point bending strength and heating line shrinkage ( 1200 ° C. × 24 hours), and the obtained results are shown in Table 1 below. The bulk density was calculated by measuring the weight and volume of the refractory heat insulating material. Thermal conductivity (600 ° C) is JIS A1412-1 (Method for measuring thermal resistance and thermal conductivity of thermal insulation, Part 1: Protection hot plate method (GHP method)), 3-point bending strength is JIS R2619 (Fireproof) Test method for bending strength of heat-insulating bricks) and heating wire shrinkage were measured according to JIS R3311 (ceramic fiber blanket).

[Example 2]
The same ceramic fiber as in Example 1 was subjected to a heat treatment in the same manner as in Example 1 with a non-fibrous particle content of 19.3% by weight and in the same manner as in Example 1. A refractory heat insulating material of Example 2 having a length of 900 mm, a width of 600 mm, and a thickness of 25 mm was produced in the same manner as in Example 1 except that this silica alumina fiber was used.

The bulk density of the obtained refractory heat insulating material after drying was 200 kg / m ³ . Moreover, about the fireproof heat insulating material after drying, it carried out similarly to the said Example 1, and measured and obtained a chemical component, thermal conductivity (600 degreeC), three-point bending strength, and a heating linear shrinkage rate (1200 degreeC x 24 hours). The results obtained are shown in Table 1 below.

[Example 3]
As the ceramic fiber, a biosoluble fiber (trade name BSSR) having an average fiber diameter of 4.3 μm and a non-fibrous particle content of 59% by weight was used. The biosoluble fiber was poured into water to disperse it and allowed to stand to float the biosoluble fiber and settle non-fibrous particles. After the non-fibrous particles have sufficiently settled, the non-fibrous particles are removed by collecting the biosoluble fibers floating near the water surface, and the content of the non-fibrous particles is 9.8% by weight. Biosoluble fibers were collected.

  Next, the biosoluble fiber (non-fibrous particle content: 9.8% by weight) was subjected to a heat treatment at 1050 ° C. for 1.5 hours. By adding the biosoluble fiber and the inorganic binder after the heat treatment to water and stirring for several minutes, a slurry containing 95% by weight of the biosoluble fiber and 5% by weight of the inorganic binder was formed. An aqueous solution of an organic polymer flocculant was added to the slurry to cause aggregation, and suction molding was performed using a mold into a plate shape of 900 mm long × 600 mm wide × 25 mm thick.

The obtained plate-shaped molded body was dried at 120 ° C. to produce the fireproof heat insulating material of Example 3. The bulk density of the refractory heat insulating material after drying was 200 kg / m ³ . Moreover, about the refractory heat insulating material after drying, it measured similarly to the said Example 1, and measured a chemical component, thermal conductivity (600 degreeC), three-point bending strength, and a heating linear shrinkage rate (1100 degreeC x 24 hours). The results obtained are shown in Table 1 below.

[Example 4]
The same biosoluble fiber as in Example 3 was heat-treated in the same manner as in Example 3 so that the content of non-fibrous particles was 19.8% by weight and the same as in Example 3. A refractory heat insulating material of Example 4 having a length of 900 mm, a width of 600 mm, and a thickness of 25 mm was produced in the same manner as in Example 3 except that this biosoluble fiber was used.

The bulk density of the obtained refractory heat insulating material after drying was 210 kg / m ³ . Moreover, about this fire-resistant heat insulating material after drying, it measured the chemical composition, thermal conductivity (600 ° C.), three-point bending strength and heating linear shrinkage (1100 ° C. × 24 hours) in the same manner as in Example 1. The obtained results are shown in Table 1 below.

[Example 5]
The same ceramic fiber as in Example 1 (a ceramic fiber having an average fiber diameter of 2.3 μm and a non-fibrous particle content of 10.7% by weight subjected to a heat treatment at 1280 ° C. for 1.5 hours) And an inorganic binder were added to water and stirred for several minutes to form a slurry containing 75% by weight ceramic fibers and 25% by weight inorganic binder. This slurry was suction-molded into a plate shape of 900 mm long × 600 mm wide × 25 mm thick using a mold.

The obtained plate-like molded body was dried at 120 ° C. to produce the fireproof heat insulating material of Example 5. The bulk density of the refractory insulation after drying was 310 kg / m ³ . Moreover, about this fire-resistant heat insulating material after drying, it measured the chemical composition, thermal conductivity (600 ° C.), three-point bending strength, and heating linear shrinkage (1200 ° C. × 24 hours) in the same manner as in Example 1. The obtained results are shown in Table 1 below.

[Comparative Example 1]
Example 1 except that the same silica alumina fiber (non-fibrous particle content 53 wt%) as in Example 1 above was used as the ceramic fiber, without removing the non-fibrous particles and without performing heat treatment. In the same manner as in Example 1, a fireproof heat insulating material of Comparative Example 1 having a length of 900 mm, a width of 600 mm, and a thickness of 25 mm was produced.

The bulk density of the obtained refractory heat insulating material after drying was 270 kg / m ³ . Moreover, about this fire-resistant heat insulating material after drying, it measured the chemical composition, thermal conductivity (600 ° C.), three-point bending strength and heating linear shrinkage (1200 ° C. × 24 hours) in the same manner as in Example 1. The obtained results are shown in Table 2 below.

[Comparative Example 2]
As the ceramic fiber, the same silica alumina fiber (non-fibrous particle content 53 wt%, no heat treatment) as in Comparative Example 1 was used. A slurry containing 75% by weight of the silica-alumina fiber, 20% by weight of titanium oxide powder as a heat radiation scattering material, and 5% by weight of an inorganic binder was formed. An aqueous solution of an organic polymer flocculant was added to the slurry and agglomerated to form a plate having a length of 900 mm × width of 600 mm × thickness of 25 mm using a mold to produce a fireproof heat insulating material of Comparative Example 2.

The bulk density of the obtained refractory heat insulating material after drying was 290 g / m ³ . Moreover, about this fire-resistant heat insulating material after drying, it measured the chemical composition, thermal conductivity (600 ° C.), three-point bending strength and heating linear shrinkage (1200 ° C. × 24 hours) in the same manner as in Example 1. The obtained results are shown in Table 2 below.

[Comparative Example 3]
As the ceramic fiber, the same biosoluble fiber (non-fibrous particle content 59% by weight) as in Example 3 above was used except that the treatment for removing the non-fibrous particles was not performed and the heat treatment was not performed. In the same manner as in Example 3, the refractory heat insulating material of Comparative Example 3 was produced.

The bulk density of the obtained refractory heat insulating material after drying was 271 g / m ³ . Moreover, about this fire-resistant heat insulating material after drying, it measured the chemical composition, thermal conductivity (600 ° C.), three-point bending strength and heating linear shrinkage (1100 ° C. × 24 hours) in the same manner as in Example 1. The obtained results are shown in Table 2 below.

[Consideration of Table 1 and Table 2]
As can be seen from Table 1 above, the refractory heat insulating materials of Examples 1 to 5 according to the present invention using ceramic fibers having a non-fibrous particle content of 20% by weight or less and subjected to heat treatment in advance have a thermal conductivity. Comparative example in which the value of the refractory material is reduced to about 50% of the refractory heat insulating material of Comparative Example 1 using the ceramic fiber from which the non-fibrous particles of the conventional example are not removed, and a heat radiation scattering material (titanium oxide) is further added. A decrease of more than 20% was also exhibited with respect to the refractory insulation material No. 2. These results indicate that reducing the non-fibrous particle content is very effective in reducing the thermal conductivity of the refractory insulation.

The thermal conductivity of the refractory heat insulating material also depends on the bulk density. Generally, in a refractory heat insulating material, when the bulk density increases to about 350 to 400 kg / m ³ , the thermal conductivity tends to decrease as the bulk density increases. This is indicated by the thermal conductivity results of Example 5.

  The bending strength of the refractory heat insulating material of Example 1 using ceramic fibers having a non-fibrous particle content of 10.7% by weight was compared with the conventional example using a ceramic fiber having a non-fibrous particle content of 53% by weight. The bending strength of the refractory insulation of Example 2 using ceramic fibers having a non-fibrous particle content of 19.3% by weight reaches 1.7 times that of the refractory insulation of Example 1 and also reaches 1.7 times. did. This is a result of an increase in the bending strength because the ceramic fiber content in the refractory insulation is increased by reducing the non-fibrous particle content.

The bending strength increases as the bulk density increases, and increases when an organic polymer flocculant is added or the amount thereof is increased. The reason why the bending strength is low even when the bulk density of Example 5 is larger than that of Examples 1 and 2 is that it does not contain an organic polymer flocculant.

  And the non-fibrous particle content is 20 wt% or less, and the refractory heat insulating materials of Examples 1 to 5 using ceramic fibers that have been heat-treated in advance are the refractory heat resistance of Comparative Examples 1 to 3 that are not heat-treated. Compared to heat insulating materials, the heating line shrinkage is extremely small.

  Since the ceramic fiber becomes amorphous by being supercooled by the rapid cooling action at the time of fiberization, the ceramic fiber is crystallized when heated. Therefore, the refractory heat insulating material using ceramic fibers shrinks due to this crystallization, but the heating line shrinkage rate can be reduced by subjecting the ceramic fibers to heat treatment in advance.

Claims (8)

A fireproof heat insulating material comprising a ceramic fiber and an inorganic binder, wherein the ceramic fiber is previously heat-treated at a temperature of 800 to 1300 ° C., the average fiber diameter of the ceramic fiber is 1.5 to 5 μm, and the ceramic fiber The total amount of non-fibrous particles contained is 20% by weight or less of the whole fiber, the thermal conductivity at 600 ° C. is 0.060 to 0.090 W / (m · K), and the bulk density after drying is 250. A fireproof heat insulating material characterized by a bending strength after drying of ˜400 kg / m ³ and 0.4 MPa or more.   The refractory heat insulating material according to claim 1, wherein the ceramic fiber is contained in an amount of 70 to 85% by weight and the inorganic binder is contained in an amount of 15 to 30% by weight. A fireproof heat insulating material comprising a ceramic fiber, an inorganic binder, and an organic polymer flocculant, wherein the ceramic fiber is preheated at a temperature of 800 to 1300 ° C., and the average fiber diameter of the ceramic fiber is 1.5 to 1.5. 5 μm and the total amount of non-fibrous particles contained in the ceramic fiber is 20% by weight or less of the whole fiber, and the thermal conductivity at 600 ° C. is 0.060 to 0.090 W / (m · K), drying. A refractory heat insulating material having a bulk density after 150 to 300 kg / m ³ and a bending strength after drying of 0.6 MPa or more.   The ceramic fiber according to claim 3, comprising 85 to 99.5% by weight of the ceramic fiber, 0.5 to 15% by weight of the inorganic binder, and 0.4 to 12% by weight of the organic polymer flocculant. Refractory insulation.   The fireproof heat insulating material according to any one of claims 1 to 4, wherein the ceramic fibers are silica alumina fibers, silica alumina zirconia fibers, or biosoluble fibers.   A method for producing a refractory heat insulating material comprising a ceramic fiber and an inorganic binder, wherein ceramic fibers having an average fiber diameter of 1.5 to 5 μm are classified to make the total of non-fibrous particles 20% by weight or less of the whole fiber. Thereafter, the ceramic fiber is heat-treated at a temperature of 800 to 1300 ° C., then the ceramic fiber is dispersed in water, an inorganic binder is added and mixed, and dehydration molding is performed by suction using a mold. A method for manufacturing a refractory insulation.   A method for producing a refractory heat insulating material comprising a ceramic fiber, an inorganic binder, and an organic polymer flocculant, wherein ceramic fibers having an average fiber diameter of 1.5 to 5 μm are classified and the total amount of non-fibrous particles is reduced over the entire fiber. After the content is adjusted to 20% by weight or less, the ceramic fiber is heated at a temperature of 800 to 1300 ° C., then the ceramic fiber is dispersed in water, an inorganic binder is added and mixed, and an organic polymer flocculant is further added. A method for producing a refractory heat insulating material, characterized in that dehydration molding is performed by suction using a mold.   The method for producing a refractory heat insulating material according to claim 6 or 7, wherein the bulk density of the molded body obtained by the dehydration molding is adjusted by a roller press.