Standard joint material for hot installation
Technical field
[0001]
　The present invention relates to a standard joint material for joining two nozzles, a joint portion of the equipment, etc. in equipment for continuous casting or refining of molten metal, and in particular, in hot water of about 200 ° C. to about 1000 ° C. Regarding what is installed.
Background technology
[0002]
　For example, in continuous steel casting equipment, joints such as gaskets and standard joint materials are used to prevent air intrusion and molten steel leakage from the joint surface between the lower nozzle and the long nozzle and between the lower nozzle and the immersion nozzle. The material is used.
[0003]
　The gasket is a molded body of alumina-silica inorganic fiber, and is mainly used for long nozzle joining in which nozzle replacement is required for each charge of continuous casting. This is because the gasket does not ignite when installed hot, can be installed reliably, does not fuse with the long nozzle during use, and has good peelability after use.
　However, the gasket is a porous material with a porosity of 80% or more, and sufficient hot sealing property (hereinafter referred to as "hot sealing property") cannot be obtained. There is a problem with the durability of the nozzle.
[0004]
　The standard joint material is a compound containing mainly various inorganic raw materials, kneaded with an organic (resin-based) binder, a plasticizer, a solvent, etc., and then molded and dried. Such a standard joint material is a refractory joint material that has been processed into a shape close to the shape of the target portion to be joined in advance, and has a particularly high hot sealing property with respect to the gasket, and is widely applied to the joint portion between nozzles. There is.
[0005]
　As such a fixed joint material, for example, in Patent Document 1, 20 to 40% by mass of an acrylic emulsion as a binder is added externally to 100% by mass of a raw material mixture composed of a fireproof raw material, and texanol is further added as a plasticizer. Disclosed is a fixed-form joint material in which 1 to 3% by mass is added by an outer hook, kneaded, molded, and dried.
Prior art literature
Patent documents
[0006]
Patent Document 1: Japanese Unexamined Patent Publication No. 2009-227538
Outline of the invention
Problems to be solved by the invention
[0007]
　The standard joint material installed between the nozzles for continuous casting is about 200 ° C to 1000 ° C during continuous discharge of molten steel (for example, during the charge of continuous casting such as when changing pots) or after preheating and before starting casting. It may be installed in a high temperature condition.
　In this case, since the organic additives such as resin-based binders and plasticizers contained in the standard joint material are flammable, the organic additives are gasified when they are installed hot and suddenly reach a high temperature. May burn, causing flames and smoke. When flames and smoke occur, the visibility of joints and standard joints deteriorates. When the visibility deteriorates, the standard joint material cannot be installed in the proper position and a gap is created between the nozzles, which reduces the sealing performance due to the suction of air, and the oxidation of the vicinity of the nozzle joint or the inner hole due to this, Oxidation of molten steel is likely to occur, or the risk of leaking steel increases.
[0008]
　Therefore, an object to be solved by the present invention is to suppress flame and smoke due to combustion of combustibles in the standard joint material while maintaining the hot sealing property of the standard joint material.
Means to solve problems
[0009]
　The present invention is the standard joint material according to the following 1 to 9.
1. 1.
　A 　compound containing 50% by mass or more and 90% by mass or less of aluminum hydroxide raw material which is a gibsite,
　1% by mass or more and 9% by mass or less of clay, 9%
　by mass or more and 23% by mass or less of graphite, and the
balance mainly composed of other fireproof raw materials. A
　standard joint material for hot installation, which is obtained by adding 26% by mass or more and 50% by mass or less of an organic additive to 100% by mass, kneading, molding and drying.
2.
　The standard joint material for hot installation according to 1 above, wherein the aluminum hydroxide raw material has a particle size of 1 μm or more and 0.25 mm or less.
3. 3.
　The hot installation according to 1 or 2 above, wherein the remaining fireproof raw material in the formulation is one or more selected from an alumina raw material, a spinel raw material, a zircon raw material, a zirconia raw material, a magnesia raw material and a silica raw material. Standard joint material.
4.
　The standard joint material for hot installation according to any one of 1 to 3 above, wherein the graphite is scaly graphite having a particle size of 0.2 mm or more.
5.
　The external organic additive contains a binder and a plasticizer, and the amount of the binder added is 25% by mass or more and 45% by mass or less, and the amount of the plasticizer added is 1% by mass or more and 5% by mass or less. The standard joint material for hot installation according to any one of 1 to 4 above.
6.
　The standard joint material for hot installation according to 5 above, wherein the binder is an ethylene vinyl acetate emulsion and the resin concentration thereof is 40% by mass or more and 60% by mass or less.
7.
　The standard joint material for hot installation according to 5 or 6 above, wherein the plasticizer is texanol monoisobutyrate or texanol diisobutyrate.
8.
　The standard joint material for hot installation according to any one of 1 to 7 above, wherein the drying temperature is 60 ° C. or higher and 100 ° C. or lower.
9.
　The standard joint material for hot installation according to any one of 1 to 8 above, which is installed between nozzles for continuous casting of two steels having a temperature of at least one of 200 ° C. or higher.
[0010]
　The features of the present invention will be described below.
　Aluminum hydroxide, which is a type of metal hydroxide, absorbs remarkable heat when heated to a high temperature and at the same time releases nonflammable gas such as water molecules. At this time, flame retardancy is imparted to the standard joint material containing an organic additive by the cooling effect caused by the generation of water vapor due to endothermic and decomposition and the effect of blocking air, that is, oxygen by the surrounding water vapor layer.
[0011]
　Combustion of standard joint material generally follows the process of heat supply → generation of flammable gas → ignition by combination with oxygen in the air → combustion expansion → fire extinguishing. From these, in order to suppress combustion or flame and smoke, (a) suppression of flammable gas release, (b) dilution of flammable gas, (c) suppression of air or oxygen supply or decrease of oxygen concentration, ( D) Suppression or cooling of temperature rise, (e) Suppression of heat transfer, etc. will contribute.
　The quantitative balance between the organic additive that burns to generate gas and the water vapor released from aluminum hydroxide and the timing of the gas generation and water vapor release are important. That is, the following three are necessary for the above-mentioned flame retardant imparting process to operate efficiently.
(1) The thermal decomposition behavior of aluminum hydroxide matches the thermal decomposition behavior of organic additives such as temperature and timing.
(2) To release a sufficient amount of water vapor with respect to the amount of flammable gas generated under the condition of (1) above.
(3) It must be safe, inexpensive and stable and industrially available.
[0012]
　In the present invention, aluminum hydroxide is used as the metal hydroxide. Furthermore, among aluminum hydroxide, gibbsite (Al (OH) 3 ) is used.
　This gibbsite has a large amount of water vaporization component, that is, (OH) component, and the total heat absorption amount associated with the dehydration reaction is 2000 J / g, which is the largest among metal hydroxides. In addition, the dehydration start temperature is about 200 ° C, which is a low temperature among metal hydroxides, and it is stable at about 200 ° C or less without changing, and α-alumina having heat resistance exceeding the molten steel temperature after dehydration. It has properties such as dehydration.
[0013]
　The nature and flame retardant mechanism of this gibbsite will be further described.
　Due to the thermal decomposition characteristics of gibbsite, there are three endothermic peaks, each of which corresponds to the next dehydration reaction.
245 ° C:　
　2Al (OH) 3 → Al 2 O 3 · H 2 O + 2H 2 O (partially boehmite transfer)
320 ° C:　
　2Al (OH) 3 → Al 2 O 3 + 3H 2 O (gibbsite dehydration reaction)
550 ° C:　
　Al 2 O 3 · H 2 O → Al 2 O 3 + H 2 O (Boehmite dehydration reaction)
[0014]
　Since the water vapor release temperature due to dehydration of such gibsite is close to the combustion (pyrolysis) start temperature of 200 ° C. for the residual components after drying of the organic additives (binders, plasticizers, etc.) in the standard joint material, these standard forms Combustion of flammable gas generated from the organic additive in the joint material can be suppressed in a timely manner.
　Furthermore, the released water vapor also has a function of lowering the temperature of the standard joint material.
　In addition, aluminum hydroxide, which is a gibbsite, is industrially relatively inexpensive and can be stably obtained.
[0015]
　In addition to gibbsite, there is diaspore (AlO (OH)) as aluminum hydroxide that is relatively easily available industrially. However, the amount of water vapor generated in diaspore is as small as 1/2 or less of that of gibbsite, and the temperature of its decomposition, that is, the release of water vapor, is about 500 ° C, which is higher than the temperature range in which flammable gas is generated from the standard joint material, resulting in sufficient flame and sufficient inflammation. The smoke suppression effect cannot be expected.
　Although magnesium hydroxide can be used, the decomposition temperature is about 350 ° C., which is slightly higher than that of gibbsite, and the amount of heat absorbed is 380 cal / g, which is smaller than that of gibbsite. Therefore, the effect of suppressing inflammation and smoke is inferior to that of gibbsite.
　From the above, it is desirable to apply gibbsite in order to obtain a sufficient effect of suppressing inflammation and smoke.
[0016]
　Incidentally, it is known that aluminum hydroxide is used as a flame-retardant material or a non-flammable material in the field of building materials such as the flame-retardant sheet material disclosed in JP-A-6-272191, but the temperature is high. There is no condition to install it in the target part of the state, and the quantitative balance between the gas generation or combustion component and the water vapor released from aluminum hydroxide, the timing of the gas generation and the water vapor release, etc. are taken into consideration. Absent.
Effect of the invention
[0017]
　According to the standard joint material of the present invention, it is possible to significantly reduce inflammation and smoke when installing hot, while maintaining the hot sealing property.
　As a result, even when it is installed in a continuous casting nozzle such as a long nozzle in a high temperature state, it can be reliably installed in a predetermined position without deteriorating visibility due to inflammation and smoke. As a result, good hot sealing performance can be maintained during operation (casting using standard joint material), and damage due to oxidation near the inner holes and joints of the nozzle for continuous casting and melting due to iron oxide can be maintained. Loss can be suppressed, leakage of steel can be prevented, and deterioration of the quality of molten steel can also be prevented.
Mode for carrying out the invention
[0018]
　The dehydration reaction of aluminum hydroxide, which is a gibbsite (hereinafter, simply referred to as "aluminum hydroxide"), changes depending on its size, and when the particle size is smaller than 1 μm, the reaction according to the above-mentioned requirements is unlikely to occur. In addition, among the characteristics of the standard joint material, the particle size is 1 μm or more, especially from the viewpoint of ensuring the filling property for providing the sealing property and further ensuring the air permeability of the flammable gas and the generated water vapor. It is preferably 25 mm or less.
[0019]
　The content ratio of aluminum hydroxide in the formulation excluding the organic additive (hereinafter, simply referred to as “combination”) is selected within the range of 50% by mass or more and 90% by mass or less.
　If the content ratio of aluminum hydroxide is less than 50% by mass, the flame retardancy is lowered, and the above problem cannot be solved at the time of hot installation. When the content ratio of aluminum hydroxide exceeds 90% by mass, the amount of clay is relatively reduced, so that the shape retention and flexibility are lowered, and the amount of graphite is also relatively reduced, so that the standard joint material is removed. The peelability at the time is reduced.
　However, the content ratio of this aluminum hydroxide is the organic additive (binder, plasticizer, etc.) necessary to obtain the characteristics such as flexibility, plasticity, and storage stability (small change with time) of the standard joint material. ) Is determined by the balance with the amount. That is, the specific content ratio of aluminum hydroxide depends on the individual operating conditions, specifically, the nozzle temperature at the time of installing the standard joint material, the flexibility required in the individual operating conditions, and the like. It may be appropriately determined according to the amount of the organic additive, that is, the combustible material as a result of the adjustment.
[0020]
　Clay is used to impart plasticity, and clay containing montmorillonite such as bentonite and having plasticity can be used.
　The content ratio of the clay in the formulation is 1% by mass or more and 9% by mass or less. If the clay content is less than 1% by mass, the plasticity of the kneaded product is insufficient and the moldability is lowered. On the other hand, if the clay content exceeds 9% by mass, the kneaded product becomes hard, making molding difficult and increasing the required amount of organic additives to alleviate it, resulting in an increase in combustible components. Therefore, flames and smoke are likely to occur or increase during hot installation.
[0021]
　Graphite is used in a content ratio of 9% by mass or more and 23% by mass or less in the formulation for the purpose of preventing fusion with the installation surface such as a nozzle and improving the peelability from the installation surface after use.
　If the graphite content is less than 9% by mass, there is a tendency for fusion to join objects, especially refractory nozzles, and the peelability is reduced, which hinders nozzle removal and fixed joint material replacement work. If the graphite content exceeds 23% by mass, there is no problem with peelability, but the kneaded product loses its plasticity and molding becomes difficult. In addition, the strength of the joint material in use is reduced, the hot sealing property is lowered, or elution or wear is likely to occur in the molten steel, which causes a problem in the protective function of the joint.
　The graphite used is preferably scaly graphite having a particle size of 0.2 mm or more. Since the scaly graphite having a particle size of 0.2 mm or more has a large surface area as a continuum, it is effective in preventing fusion between the constituents in the formulation or between them and the binder. The upper limit of the particle size of scaly graphite is not particularly limited, but industrially available ones are generally 0.5 mm or less.
[0022]
　The rest of the formulation consists mainly of other fireproof raw materials. The refractory raw material is preferably selected from an alumina raw material, a spinel raw material, a zircon raw material, a zirconia raw material, and a magnesia raw material.
　In the standard joint material, these fireproof raw materials are unlikely to cause a reaction such as low melting with α-alumina generated by changing aluminum hydroxide, and the stability of the standard joint material can be maintained. The remaining fire-resistant raw material has a particle size of more than 0.25 mm as long as it has a size (particle size) equal to or less than the joint thickness and an amount that does not impair the filling property of the standard joint material. It may contain a fireproof material.
[0023]
　Here, the alumina raw material refers to those mainly composed of alumina such as corundum, silimanites, and mullite, the spinel raw material refers to the positive spinel of alumina and magnesia, and the zirconia raw material refers to the zirconia raw material regardless of the type of stabilizer. It may be stabilized or unstabilized regardless of the degree of stabilization, and the magnesia raw material refers to a raw material containing pericrace as a main component and an MgO component of approximately 80% by mass or more.
[0024]
　If the silica raw material is a high-purity product, it may form mullite with α-alumina, and it can be used as a fire-resistant raw material that constitutes the balance of the compound.
　However, if there are many impurities in the foreign slag component or silica raw material, low melt may be generated and cause melting damage or wear. Therefore, depending on the operating conditions such as usage time and temperature, for example. , The type of raw material, etc. may be selected as appropriate. When the silica raw material is used in combination with another fireproof raw material, it is preferable to use it in combination with a raw material other than the magnesia raw material because a low melt may be produced with the magnesia raw material.
[0025]
　The fire-resistant raw material that constitutes the balance of these formulations is not limited to artificial or natural, and the manufacturing method does not matter.
[0026]
　In the standard joint material of the present invention, the total amount of the organic additive is added by an external amount of 26% by mass or more and 50% by mass or less with respect to 100% by mass of the above-mentioned compound. This organic additive mainly consists of a binder and a plasticizer.
[0027]
　Ethylene vinyl acetate emulsion can be used as the binder. As this ethylene vinyl acetate emulsion, a commercially available product having a resin concentration of 40% by mass or more and 60% by mass or less (mainly water other than the resin content) can be used. This resin component becomes a combustible material. If the resin concentration is less than 40% by mass, the film forming mechanism at the time of drying becomes insufficient, and it becomes difficult to standardize the joint material. If the resin concentration exceeds 60% by mass, inflammation and smoke during use become intense, which may cause explosion, which is not preferable.
　The viscosity of the ethylene vinyl acetate emulsion is preferably 100 to 500 cps at 25 ° C. If the viscosity is less than 100 cps, the kneaded product may lack plasticity and may be damaged during molding, making molding difficult. If the viscosity exceeds 500 cps, the viscosity may be too high and it may be difficult to knead uniformly.
　Further, the pH of the ethylene vinyl acetate emulsion is preferably about 4 to 8. If the pH is less than about 4, it is strongly acidic and harmful to the human body, so care must be taken when handling it during work. When the pH becomes highly alkaline, which exceeds about 8, the harmfulness to the human body becomes high, and care must be taken in handling during work, and the change over time (curing phenomenon) of the kneaded material due to the reaction with the fireproof raw material becomes large. Possibility arises. Therefore, it is preferable that the pH is in the stable range of about 4 to 8.
[0028]
　The amount of the ethylene vinyl acetate emulsion added is 25% by mass or more and 45% by mass or less, with the above-mentioned compound being 100% by mass. If the amount of the ethylene vinyl acetate emulsion added is less than 25% by mass, or if it exceeds 45% by mass, a kneaded product can be obtained, but plasticity, shape retention, and the like occur. When the amount of the ethylene vinyl acetate emulsion added is 25% by mass or more and 45% by mass or less, a kneaded product having shape retention and good moldability can be obtained.
[0029]
　The plasticizer imparts plasticity, but is mainly used for imparting flexibility in the use of standard joint materials. In the present invention, it is preferable to use a substance other than phthalic acid. This is because phthalic acid-based plasticizers have safety and environmental problems.
　As the non-phthalic acid-based plasticizer, butyl-based texanol monoisobutyrate or texanol diisobutyrate (hereinafter collectively referred to as "texanol") is preferable from the viewpoint of compatibility with the above-mentioned binder. .. In addition, texanol has a high ignition point of 390 ° C, does not violate the PRTR method and VOC regulations, and is not suspected to be an endocrine disrupter. Therefore, it is possible to provide an environment-friendly standard joint material.
[0030]
　The amount of the plasticizer added shall be 1% by mass or more and 5% by mass or less, with the composition being 100% by mass. If the amount of plasticizer added is less than 1% by mass, sufficient plasticity cannot be obtained, and if it exceeds 5% by mass, excess plasticizer remains in the joint material and deteriorates over time. In the meantime, cracks may occur in the joint material and the sealing performance may be poor.
[0031]
　The standard joint material of the present invention is obtained by adding the above-mentioned organic additive to the above-mentioned compound, kneading, molding and drying, and for kneading, a mixer generally used for kneading refractories. For example, a blade-type spiral mixer, a planetary mixer, a cooking mixer, an Erich mixer, or the like can be used. In kneading, pressure may be applied as long as the particles of the formulation are not destroyed and the particle size and morphology of each raw material are not significantly destroyed.
　In addition to the above-mentioned formulations and organic additives, water and other solvents can be added as appropriate for kneading feces. In this case, it is preferable that it evaporates and disappears when it dries.
[0032]
　For molding, for example, a uniaxial hydraulic molding machine, which is generally used for molding refractories, can be used. The molding pressure may be arbitrarily set according to the shape of the product, the pressure-bonding structure, the density according to the strength, and the conditions for each individual operation.
[0033]
　Drying is classified into batch type and continuous type from the operation method, direct and indirect from the heating method, hot air drying from the heat source, combined use of hot air and wet body direct energization, infrared drying with electric heat or radiant tube, microwave drying, etc. it can.
　Of these, for drying the molded body in the present invention, a direct heat heating type hot air drying furnace using an electric heating drying furnace that can be used relatively easily, particularly a batch type electric heating drying furnace (box type or shelf-stage type) is used. It is preferable to carry out using the above.
　The drying temperature is preferably 60 ° C. or higher and 100 ° C. or lower. This is to more reliably obtain the flexibility of the joint material due to the film formation of the above-mentioned organic additive after drying.
　If the drying temperature is less than 60 ° C., this film formation becomes insufficient and the film formation tends to be incomplete in the entire standard joint material, and as a result, cracks may occur during handling and the flexibility may be inferior. On the other hand, if the drying temperature exceeds 100 ° C., the film formation becomes too strong and the standard joint material is hardened, so that the flexibility tends to be inferior.
　The properties of these standard joint materials are also affected by the holding time at these drying temperatures.
[0034]
　When the standard joint material of the present invention is installed on, for example, a preheated refractory nozzle, the binder (ethylene vinyl acetate resin) is first melted and softened by the heat of the refractory, and the standard joint material itself. Becomes soft. While this state is maintained, pressure is applied between the two nozzles to be joined within about 1 minute, so that the pressure is applied, the filling degree of the internal structure is increased, and sufficient hot sealing property can be ensured. Since it contains graphite, it does not fuse with the joint surface with the nozzle during operation, the joint material can be easily peeled off after use, and reaction or melting damage with molten steel or slag is unlikely to occur.
Example
[0035]
　The compositions of the formulations A to M used in Examples and Comparative Examples of the present invention are shown in Tables 1 and 2. The purity of each raw material is 95% or more. In addition, Tables 3 and 4 show the compounding composition and evaluation results of the standard joint material prepared by using these compounds A to M. As the ethylene vinyl acetate emulsion as the binder, one having a resin concentration of 58% by mass, a viscosity of 200 cps, and a pH of 5 was used. As the plasticizer texanol, texanol monoisobutyrate, which is 2,2,4-trimethyl-1,3-pentadiol monoisobutyrate, was used.
[0036]
　Each evaluation shown in Tables 3 and 4 was performed by the following method.
　The moldability of the kneaded product was evaluated based on the plasticity of the kneaded product and whether or not a desired shape was obtained after pressure molding.
　The shape retention at room temperature was evaluated by using the spring-type hardness test described in the JIS-K6301 vulcanized rubber physical test method and evaluating the degree of penetration of the push needle from the joint material surface with an exponential notation of 0 to 100. The larger the value of this exponential notation, the harder the joint material, and the smaller the value, the softer the joint material.
　To evaluate the flame retardancy, a standard joint material was placed on the refractory brick heated to 800 ° C., and the presence or absence of combustion or flame and smoke was observed.
　The hot sealability is measured by measuring the time from the state where a fixed joint material is installed between the fire-resistant bricks heated to 600 ° C and the pressure is reduced to 0.5 atm to the time when it returns to the atmospheric pressure of 1 atm as the recovery time. evaluated. The longer the recovery time, the higher the hot sealing property.
　To evaluate the peelability after use, place a standard joint material on a refractory brick heated to 800 ° C (hereinafter referred to as "800 ° C heated brick"), and after 1 minute, cover it with another 800 ° C heated brick to form a standard shape. The joint material was sandwiched, placed in a furnace at 1100 ° C., weighted at 5 kg / cm 2 for 15 minutes, then taken out and evaluated by the ease of peeling the bricks.
　Based on each of the above evaluations, the comprehensive evaluation as a standard joint material was evaluated on a scale of ◎ (good), ○ (possible), and × (impossible), and ◎ and ○ were passed.

[0041]
　First, examples of the present invention shown in Table 3 will be described.
[0042]
　In Example 1, an ethylene vinyl acetate emulsion (binder) 25% by mass and a texanol (plasticizer) 1 were added to a formulation A composed of 90% by mass of aluminum hydroxide, 1% by mass of clay, and 9% by mass of black smoke. Mass% is added externally, kneaded using a desktop mixer, pressure-molded into a sheet with a thickness of 3 mm, dried at about 80 ° C., and a standard joint material is formed by forming an emulsion by evaporation of water. It was prepared and evaluated.
　The flame retardancy was evaluated to be good with no flames, and the value measured by the spring-type hardness tester described in the JIS-K6301 vulcanized rubber physical test method was 50 to 60, which is shape retention at room temperature and is hot. The sealing property and the peeling property after use were also good.
[0043]
　In Example 2, the ethylene vinyl acetate emulsion (binder) 35% by mass and the texanol (plasticizer) 3 were added to the formulation B composed of 82% by mass of aluminum hydroxide, 9% by mass of clay, and 9% by mass of black smoke. Mass% was added externally to prepare a standard joint material in the same manner as in Example 1, and evaluation was performed.
　In the flame retardancy evaluation, there was no flame and it was good, and the shape retention at room temperature, the hot sealability, and the peelability after use were also good.
[0044]
　In Example 3, 40% by mass of an ethylene vinyl acetate emulsion (binder) and 4% by mass of texanol (plasticizer) were added externally to the same formulation B as in Example 2, and the same as in Example 1. Similarly, a standard joint material was prepared and evaluated.
　In the flame retardancy evaluation, there was no flame and it was good, and the shape retention at room temperature, the hot sealability, and the peelability after use were also good.
[0045]
　In Example 4, the ethylene vinyl acetate emulsion (binder) was 30% by mass and the texanol (plasticizer) was 2% by mass with respect to the formulation C composed of 79% by mass of aluminum hydroxide, 4% by mass of clay, and 17% by mass of graphite. % Was added externally to prepare a standard joint material in the same manner as in Example 1, and the evaluation was performed.
　In the flame retardancy evaluation, there was no flame and it was good, and the shape retention at room temperature, the hot sealability, and the peelability after use were also good.
[0046]
　In Example 5, 35% by mass of an ethylene vinyl acetate emulsion (binder) and 3% by mass of texanol (plasticizer) were added externally to the same formulation C as in Example 4, and the same as in Example 1. Similarly, a standard joint material was prepared and evaluated.
　In the flame retardancy evaluation, there was no flame and it was good, and the shape retention at room temperature, the hot sealability, and the peelability after use were also good.
[0047]
　In Example 6, the
ethylene vinyl acetate emulsion (binder) was 40% by mass and the texanol (plasticizer) was 2% by mass with respect to the formulation D consisting of 76% by mass of aluminum hydroxide, 1% by mass of clay, and 23% by mass of graphite. % Was added externally to prepare a standard joint material in the same manner as in Example 1, and the evaluation was performed.
　In the flame retardancy evaluation, there was no flame and it was good, and the shape retention at room temperature, the hot sealability, and the peelability after use were also good.
[0048]
　In Example 7, the ethylene vinyl acetate emulsion (binder) 45% by mass and the texanol (plasticizer) 5% by mass are based on the formulation E composed of 68% by mass of aluminum hydroxide, 9% by mass of clay, and 23% by mass of graphite. % Was added externally to prepare a standard joint material in the same manner as in Example 1, and the evaluation was performed.
　In the flame retardancy evaluation, there was no flame and it was good, and the shape retention at room temperature, the hot sealability, and the peelability after use were also good.
[0049]
　In Example 8, the ethylene vinegar emulsion (binding agent) 30 was added to the formulation F composed of 50% by mass of aluminum hydroxide, 40% by mass of an alumina (aluminum oxide) raw material, 1% by mass of clay, and 9% by mass of graphite. A standard joint material was prepared and evaluated in the same manner as in Example 1 by adding 1% by mass of texanol (plasticizer) by mass% and 1% by mass of texanol (plastic agent).
　In the flame retardancy evaluation, there was no flame and it was good, and the shape retention at room temperature, the hot sealability, and the peelability after use were also good.
[0050]
　In Example 9, the ethylene vinegar emulsion (binding agent) 45 was added to the formulation G composed of 50% by mass of aluminum hydroxide, 18% by mass of an alumina (aluminum oxide) raw material, 9% by mass of clay, and 23% by mass of graphite. A standard joint material was prepared and evaluated in the same manner as in Example 1 by adding mass% and 5% by mass of texanol (plasticizer) externally.
　In the flame retardancy evaluation, there was no flame and it was good, and the shape retention at room temperature, the hot sealability, and the peelability after use were also good.
[0051]
　Next, a comparative example shown in Table 4 will be described.
[0052]
　In Comparative Example 1, the content of aluminum hydroxide was 46% by mass, which was less than the lower limit of the present invention, and 45% by mass of an ethylene vinyl acetate emulsion (binder) and 4% by mass of texanol (plasticizer). % Was added externally and kneaded using a tabletop mixer in the same manner as in Example 1. The moldability of the kneaded product was good, and the shape retention at room temperature after drying was also good, but inflammation was observed because the content ratio of aluminum hydroxide was too low. For this reason, the evaluation of hot sealability and the evaluation of peelability after use could not be advanced, and the overall evaluation was x.
[0053]
　In Comparative Example 2, the content of aluminum hydroxide was 92% by mass, which exceeded the upper limit of the present invention, and the content of graphite was 7% by mass, which was lower than the lower limit of the present invention. 38% by mass of the system emulsion (binder) and 4% by mass of the texanol (plasticizer) were added externally and kneaded using a tabletop mixer in the same manner as in Example 1. The moldability of the kneaded product was good, and the shape retention at room temperature after drying was also good. However, because the content of aluminum hydroxide was too high, the content of graphite was relatively low, causing seizure on refractory bricks and reducing the peelability after use.
[0054]
　Comparative Example 3 is the same as in Example 1 in which 25% by mass of an ethylene vinyl acetate emulsion (binder) and 2% by mass of texanol (plasticizer) are added externally to the clay-free formulation J. However, since there was no clay, the kneaded product was not plastic and could not be molded. For this reason, the evaluation of hot sealability and the evaluation of peelability after use could not be advanced, and the overall evaluation was x.
[0055]
　In Comparative Example 4, 45% by mass of an ethylene vinyl acetate emulsion (binder) and 5% by mass of texanol (plasticizer) were added to the compound K having a clay content of 10% by mass, which exceeds the upper limit of the present invention. It was added by external hook and kneaded in the same manner as in Example 1, but the kneaded product was hard and could not be molded because the content ratio of clay was too high. For this reason, the evaluation of hot sealability and the evaluation of peelability after use could not be advanced, and the overall evaluation was x.
[0056]
　In Comparative Example 5, the ethylene vinyl acetate emulsion (binder) was 35% by mass and the texanol (plasticizer) was 3% by mass with respect to the formulation L in which the graphite content was 7% by mass, which was below the lower limit of the present invention. It was added by external hook and kneaded in the same manner as in Example 1. The moldability of the kneaded product was good, the shape retention at room temperature after drying was also good, there was no inflammation, and the hot sealability was also good, but the graphite content was too low, so refractory bricks Seizure occurred on the surface, and the peelability after use decreased.
[0057]
　In Comparative Example 6, the ethylene vinyl acetate emulsion (binder) 45% by mass and the texanol (plasticizer) 5% by mass were added to the formulation M in which the graphite content was 26% by mass, which exceeded the upper limit of the present invention. It was added externally and kneaded in the same manner as in Example 1, but the kneaded product was not plastic because the content of graphite was too high, and molding was not possible. For this reason, the evaluation of hot sealability and the evaluation of peelability after use could not be advanced, and the overall evaluation was x.
[0058]
　In Comparative Example 7, the same evaluation was performed on a commercially available gasket currently used as a joint material between the lower nozzle and the long nozzle.
　As shown in Table 4, although there was no seizure on the refractory brick, the hot sealing property was inferior, and therefore it was judged to be unsuitable as a joint material. The result is the same as the actual furnace.
[0059]
　As described above, in Examples 1 to 9 within the scope of the present invention, while maintaining the hot sealing property, there is no inflammation or smoke, and there is no fusion with the nozzle to be joined, and the nozzle and the fixed joint material are not fused. The replacement work can be carried out easily and reliably. Moreover, since the heat sealing property and the protection of the joints can be maintained, high-quality steel can be obtained without entrainment of the atmosphere (air) during operation.
The scope of the claims
[Claim 1]
　A 　compound containing 50% by mass or more and 90% by mass or less of aluminum hydroxide raw material which is a gibsite,
　1% by mass or more and 9% by mass or less of clay, 9%
　by mass or more and 23% by mass or less of graphite, and the
balance is mainly composed of other fireproof raw materials. A
　standard joint material for hot installation, which is obtained by adding 26% by mass or more and 50% by mass or less of an organic additive to 100% by mass, kneading, molding and drying.
[Claim 2]
　The standard joint material for hot installation according to claim 1, wherein the particle size of the aluminum hydroxide raw material is 1 μm or more and 0.25 mm or less.
[Claim 3]
　The heat according to claim 1 or 2, wherein the remaining fireproof raw material in the formulation is one or more selected from an alumina raw material, a spinel raw material, a zircon raw material, a zirconia raw material, a magnesia raw material and a silica raw material. Standard joint material for inter-installation.
[Claim 4]
　The standard joint material for hot installation according to any one of claims 1 to 3, wherein the graphite is scaly graphite having a particle size of 0.2 mm or more.
[Claim 5]
　The outer organic additive contains a binder and a plasticizer, and the amount of the binder added is 25% by mass or more and 45% by mass or less, and the amount of the plasticizer added is 1% by mass or more and 5% by mass or less. The standard joint material for hot installation according to any one of items 1 to 4.
[Claim 6]
　The standard joint material for hot installation according to claim 5, wherein the binder is an ethylene vinyl acetate emulsion, and the resin concentration thereof is 40% by mass or more and 60% by mass or less.
[Claim 7]
　The standard joint material for hot installation according to claim 5 or 6, wherein the plasticizer is texanol monoisobutyrate or texanol diisobutyrate.
[Claim 8]
　The standard joint material for hot installation according to any one of claims 1 to 7, wherein the drying temperature is 60 ° C. or higher and 100 ° C. or lower.
[Claim 9]
　The standard joint material for hot installation according to any one of claims 1 to 8, which is installed between nozzles for continuous casting of two steels having a temperature of at least one of 200 ° C. or higher.