Fibrous aggregate for spray material, raw material for spray material containing the same, and method for applying spray material using the same

Abstract

To provide a fibrous aggregate for a spray material in which the optimum value of the mixing ratio of a powder and a liquid is reduced as compared with a conventional fibrous aggregate for a spray material, a raw material for a spray material containing the same, and a method for applying a spray material using them.SOLUTION: The fibrous aggregates for the spray material are granular aggregates composed of ceramic fibers, have ≤ 35% compressibility index and ≤ 42 ° angle of repose, contain a water repellent and have <7. 0mm particle diameter.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fibrous aggregate for a spraying material, a raw material for a spraying material containing the same, and a method for applying the spraying material. [Background technology]

[0002] Patent document 1 describes a fibrous aggregate for spraying materials, which is a granular aggregate containing ceramic fibers and a binder, has a compressibility index of 55% or less, an angle of repose of 58° or less, and an aggregate particle size of less than 7.0 mm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7219957 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the fibrous aggregate for spraying material described in Patent Document 1, a powder containing the fibrous aggregate for spraying material and a binder is stored in the storage section of the spraying machine, and when spraying work is carried out, the powder can be supplied smoothly without clogging the storage section or forming ratholes in the powder.

[0005] The powder is prepared by mixing liquid and powder (solids) at the tip of the spraying machine near the spray nozzle and spraying it onto the workpiece. There is an optimum ratio of liquid to solids for the spraying process. If the amount of liquid is low relative to the solids, a rebound occurs when the sprayed material is sprayed onto the workpiece, and a large amount of dust is generated. If the amount of liquid is high relative to the solids, the sprayed material drips off the workpiece when sprayed onto the workpiece. The invention of Patent Document 1 focuses on the fluidity of the powder stored in the storage section, but does not consider the adhesion performance of the sprayed material to the workpiece, the amount of dust generated, rebound loss, or dripping of the sprayed material.

[0006] If the amount of liquid added to the powder is too large, the performance of the applied product will be reduced. Over time, the liquid contained in the applied product will evaporate and dissipate. After the liquid dissipates, voids will form in the applied product where the liquid was present, reducing the strength of the applied product. Therefore, it is preferable to add a small amount of water when spraying.

[0007] The present invention aims to provide a fibrous aggregate for spraying materials that has excellent fluidity of solids and can reduce the amount of liquid mixed with the solids, a raw material for spraying materials containing the same, and a method for applying the spraying materials using the same. [Means for solving the problem]

[0008] The above problem is solved by providing a fibrous aggregate for spraying materials, which is a granular aggregate composed of ceramic fibers, has a compressibility index of 35% or less, an angle of repose of 42° or less, contains a water repellent agent, and has a particle size of less than 7.0 mm.

[0009] The above problems are also solved by a raw material for a spraying material containing a fibrous aggregate for a spraying material and a binder for a spraying material.

[0010] The above problem is solved by a method for applying spray material in which the fibrous aggregate or raw material for spray material is mixed with a liquid in a conveying gas to form a spray material, and the spray material is then sprayed onto the object to be applied from the tip of the discharge port together with the conveying gas.

[0011] In the method for applying the spraying material, the fibrous aggregate for the spraying material or the raw material for the spraying material may be mixed with a liquid component in an amount of 0.6 to 1.5 times the mass of the solid component.

[0012] The bulk density of the fibrous aggregate for spraying material is 1.0 g / cm 3 It can be as follows: [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a fibrous aggregate for spraying materials that has excellent fluidity of solids and can reduce the amount of liquid mixed with the solids, a raw material for spraying materials containing the same, and a method for applying spraying materials using the same. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a diagram illustrating a configuration example of a spray machine. [Figure 2] FIG. 2 is a cross-sectional view of a powder storage section. [Figure 3] FIG. 1 is a cross-sectional view of a powder reservoir with a powder supply device. [Figure 4] FIG. 1 is a perspective view showing an example of a powder supplying device. DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment of the present invention will be described. The present invention relates to a fibrous aggregate for spraying materials (hereinafter referred to as fibrous aggregate), which is a granular aggregate made of ceramic fibers, has a compressibility index of 35% or less, an angle of repose of 42° or less, contains a water repellent agent, and has a particle size of less than 7.0 mm.

[0016] The method for producing the fibrous aggregate is not particularly limited. For example, the fibrous aggregate can be produced using a ceramic fiber aggregate formed by entanglement of ceramic fibers as a raw material. Ceramic fiber aggregates are commercially available as, for example, ceramic fiber lumps or blankets.

[0017] The fibrous aggregate can be produced, for example, as follows: First, ceramic fibers are crushed in a crushing device. A water repellent is applied to the crushed ceramic fibers, and the ceramic fibers are granulated while rolling in a granulator such as a concrete mixer. The water repellent may also be applied to the fibrous aggregate after granulation. The granulated material is dried, sieved, and sized to obtain the fibrous aggregate. Water may also be impregnated into the ceramic fibers during granulation.

[0018] When granulating the crushed ceramic fibers, an appropriate granulation binder can be used. The granulation binder can be an organic binder or an inorganic binder. Examples of organic binders that can be used include carboxymethyl cellulose, carboxymethyl cellulose derivatives, polyvinyl alcohol, and gum arabic. Examples of inorganic binders that can be used include montmorillonite and zeolite.

[0019] The content of the granulation binder is not particularly limited, but for example, the content of the granulation binder contained in the fibrous aggregate after granulation can be 0.1 to 15 mass % based on the mass of the fibrous aggregate.

[0020] The water repellent agent can be commercially available. For example, a water repellent agent having a contact angle with water of 80 to 160° or 85 to 115° can be used. The contact angle is determined in accordance with JIS R 3257:1999 "Test Method for Wettability of Substrate Glass Surfaces." Known silicone resin-based water repellents or fluororesin-based water repellents can be used as water repellents having the above contact angles. Silicone resins are compounds having siloxane bonds. Examples of silicone resin-based water repellents include liquid compositions containing silicone oil or modified silicone resins, and emulsions of silicone resins. Examples of fluororesin-based water repellents include emulsions of fluororesins.

[0021] The content of the water repellent agent contained in the fibrous aggregate is not particularly limited, but can be, for example, 0.1 to 18% by mass based on the mass of the fibrous aggregate. The upper limit of the content of the water repellent agent can be, for example, 10% by mass or less, 5% by mass or less, or 3% by mass or less. The content of the water repellent agent is a value converted into the synthetic resin content contained in the water repellent agent.

[0022] The compressibility index was calculated using the following formula 1. The initial bulk density and tapped bulk density were calculated using a method based on 7.1 of JIS R 1628-1997. The smaller the compressibility index, the higher the fluidity of the fibrous aggregate or raw material for shotcrete. [Formula 1] Compressibility index (%) = [(tapped bulk density - initial bulk density) ÷ tapped bulk density] × 100

[0023] The angle of repose is the maximum angle of the slope at which fibrous aggregate remains stable without collapsing when piled up, and was measured using a tap density measuring instrument, Tap Denser (KYT-5000k), manufactured by Seishin Enterprise Co., Ltd. The smaller the angle of repose, the higher the fluidity of the fibrous aggregate or raw material for spraying material.

[0024] The particle size of the fibrous aggregate is less than 7.0 mm. The particle size is a range of particle size distribution, meaning the size that falls under a 7.0 mm mesh. The same applies to the lower limit value described below. By setting the particle size distribution range in this way, it is possible to suppress a phenomenon called rebound loss, in which the fibrous aggregate rebounds without adhering to the object to be sprayed, such as a wall, ceiling, or floor, thereby improving yield and the efficiency of the spraying operation. The lower limit value of the fibrous aggregate is not particularly limited and can be, for example, 0.3 mm or more.

[0025] The bulk density of the fibrous aggregate is 1.0 g / cm 3 Preferably, it is 0.75 g / cm or less. 3 By setting the bulk density in this range, the construction constructed by spraying the spray material can be provided with heat insulating properties, and the spray material can be made less likely to peel off or crumble when sprayed onto parts where the spray material is difficult to adhere, such as walls and ceilings. The lower limit of the bulk density is not particularly limited, but is preferably 0.1 g / cm 3 The bulk density is measured based on the tapped bulk density method in JIS R 1628-1997, 7.1.

[0026] The ceramic fibers may be selected depending on the application of the fibrous aggregate. The ceramic fibers are preferably one or more fibers selected from the group consisting of alumina fibers, mullite fibers, silica fibers, glass fibers, and rock wool. The fibers may be either crystalline or amorphous. The fiber length is not particularly limited, but fibers of 0.1 to 80 mm, for example, can be used. The fiber diameter is also not particularly limited, but fibers of 1 to 30 μm, for example, can be used.

[0027] The compressibility index is more preferably 25% or less, and even more preferably 16% or less. The lower limit of the compressibility index is not particularly limited, but can be, for example, 5% or more. The angle of repose is more preferably 35° or less. The lower limit of the angle of repose is not particularly limited, but can be, for example, 20° or more.

[0028] The above-mentioned fibrous aggregate can be used as a spraying material, for example, by mixing the fibrous aggregate, a spraying material binder, and a liquid component and spraying the mixture against an object to be treated. The above-mentioned fibrous aggregate can also be used as a spraying material, for example, by mixing the fibrous aggregate and a liquid component and spraying the mixture against an object to be treated. The above-mentioned fibrous aggregate can be mixed with a spraying material binder and distributed as a premix-type raw material for a spraying material. The above-mentioned fibrous aggregate can also be distributed alone as a raw material for a spraying material. The premix-type raw material for a spraying material or the fibrous aggregate can be used by mixing with a liquid component such as water.

[0029] Examples of the object to be insulated include walking beams, walking beam posts, and furnace ceilings, walls, or floors that require insulation. Examples of the furnace include heating furnaces such as electric furnaces and gas furnaces. The spraying material can be sprayed onto the object to repair damaged areas or to construct new linings for walls, etc.

[0030] The binder to be blended into the spray material is not particularly limited, and examples thereof include at least one binder selected from the group consisting of carboxymethylcellulose, carboxymethylcellulose derivatives, starch, gum arabic, phenolic resin, vinyl acetate, zeolite, and montmorillonite. Examples of carboxymethylcellulose derivatives include sodium carboxymethylcellulose, potassium carboxymethylcellulose, lithium carboxymethylcellulose, and ammonium carboxymethylcellulose.

[0031] The binder for spraying materials is solid. Preferably, the binder for spraying materials is powdered. Any binder for spraying materials may be used as long as it adheres to the target body when sprayed, and inorganic or organic binders can be used. The content of the binder for spraying materials is preferably 0 to 30 parts by mass, more preferably 2 to 15 parts by mass, per 100 parts by weight of fibrous aggregate. The particle size distribution range of the binder for spraying materials is not particularly limited, but can be, for example, 0.8 μm or more and 980 μm or less. The particle size referred to here is the range of particle size distribution, determined by sieving.

[0032] The liquid to be mixed with the raw material for the spraying material or the fibrous aggregate for the spraying material can be, for example, water or water containing the secondary components to be contained in the spraying material. The secondary components can be refractory powders such as alumina powder and silica powder. Colloidal silica can also be used instead of silica powder.

[0033] The particle size range of the raw material for the gunning material can be, for example, 7 mm or less. There is no particular lower limit to the particle size of the raw material for the gunning material, but it is, for example, 0.5 μm or more.

[0034] When the liquid is mixed with the fibrous aggregate for spraying material or the raw material for spraying material, for example, the liquid may be mixed in an amount of 0.6 to 2.0 times the mass of the solids. The amount of the liquid is more preferably 1.8 times or less, 1.5 times or less, or 1.3 times or less the mass of the solids.

[0035] The spray material can be efficiently sprayed onto the object using, for example, a spray machine 5 as shown in Fig. 1. The spray machine 5 in Fig. 1 includes a storage section 51, a pressurized gas supply section 52, a connection section 53 connecting the storage section 51 and the pressurized gas supply section 52, a flexible hose 54 connected downstream of the connection section, a rigid hollow tube 55 connected downstream of the flexible hose 54, and a liquid supply section 56.

[0036] Pressurized gas supply unit 52 supplies pressurized gas such as air to connection unit 53 or the like, and discharges the gas from a nozzle provided at the tip of hollow tube 55. Examples of pressurized gas supply unit 52 include a cylinder filled with pressurized gas, and an air compressor. The flow rate of the pressurized gas may be adjusted so that the solid content discharged from the nozzle is 2 to 20 kg / min, for example.

[0037] The storage section 51 is for storing solid content 511. The solid content 511 is, for example, a raw material for a spraying material containing a fibrous aggregate and a binder for the spraying material, or a fibrous aggregate. The storage section 51 may be, for example, a tank or a hopper.

[0038] The connection part 53 connects the pressurized gas supply part 52 and the storage part 51, and the pressurized gas and the solid content 511 are mixed inside the connection part 53. An example of the connection part is an ejector. The ejector uses the gas supplied from the pressurized gas supply part 52 as a driving source to suck the solid content 511 stored in the powder storage part 51 and supply it to the flexible hose 54.

[0039] Hollow tube 55 is a hollow tube made of a synthetic material such as metal, and is held by the operator as an operating rod when using sprayer 5. Compressed gas and solids 511 supplied from flexible hose 54 are transported inside. When operating hollow tube 55 to change the direction of the nozzle at the tip of hollow tube 55, flexible hose 54 elastically deforms, allowing for smooth operation. The nozzle functions as the outlet for the spray material.

[0040] Liquid supply unit 56 supplies liquid to solids 511 transported by pressurized gas through hollow tube 55. In the example of Fig. 1, liquid supply unit 56 is composed of a pipe connected to hollow tube 55 and a valve for changing the amount of liquid supplied.

[0041] A mixture 21 of a liquid component supplied from a liquid supply unit 56 and a solid component 511 supplied from a powder storage unit 51 is discharged from a nozzle provided at the tip of the hollow tube 55 together with a carrier gas.

[0042] In the above-mentioned spraying machine, the fibrous aggregate or raw material for the spraying material and the liquid are mixed in the conveying air inside the hollow tube to produce the spraying material, which is then sprayed onto the object to be treated from the tip of the tubular discharge part.

[0043] As shown in FIG. 3, a supply device for solid content 511 may be provided between powder storage section 51 and connection section 53. As shown in FIG. 4, powder supply device 6 of FIG. 3 includes a feed wheel 61 that rotates horizontally, a contact plate 62 disposed below feed wheel 61, and a cylindrical body 63 that houses feed wheel 61 and contact plate 62 and connects powder storage section 51 and connection section 53. Feed wheel 61 is substantially truncated cone-shaped, and multiple through holes 611 are formed in the outer periphery of the bottom side of the truncated cone. Furthermore, contact plate 62 is formed with a through hole 621 that penetrates a portion of the bottom. As feed wheel 61 rotates, multiple through holes 611 of feed wheel 61 sequentially communicate with through holes 621 of contact plate 62, and powder stored in storage section 51 is supplied to connection section 53.

[0044] As shown in FIG. 2, a configuration may be adopted in which a supply device for solid content 511 is not provided between powder storage section 51 and connection section 53.

[0045] The above-mentioned fibrous aggregate is less likely to clog the powder storage section and less likely to form bridges or ratholes. Therefore, it can be suitably used in a small sprayer, which is prone to problems when supplying solids. A small sprayer is, for example, a sprayer in which the flow rate of compressed gas discharged from the nozzle is 1.5 to 2.5 m 3 Examples include those with a speed of 1 / minute. [Example]

[0046] The present invention will be described in more detail below with reference to examples. The examples shown below are merely limited examples of embodiments of the present invention, and the technical scope of the present invention is not limited to the exemplified embodiments.

[0047] [Examples 1 and 6] Fibrous aggregate for spraying materials was manufactured using the following method. First, a ceramic fiber blanket, which is an aggregate of short alumina fibers with an average fiber diameter of 6.1 μm, was placed in a crusher to crush the ceramic fibers. The crusher is equipped with a roller that rotates clockwise and a roller that rotates counterclockwise, and the raw material is placed between these rollers. The crusher used is equipped with a mesh with an opening of 5.0 mm, so that fibers smaller than 5.0 mm are discharged. The average fiber diameter was confirmed using a microscope (magnification 6000x).

[0048] A mixture of ceramic fibers discharged from the disintegrator, a granulation binder, and a small amount of water was rotated along the inner wall of a concrete mixer to form granules. The mixture was rotated along the inner wall of the concrete mixer at room temperature for 30 minutes. Once the ceramic fibers had formed a certain amount of granules, silicone oil (dimethylpolysiloxane) with 100% purity, excluding unavoidable impurities, was added. The mixture was then rolled in the concrete mixer for 10 minutes to form granules. The composition of each raw material is shown in Table 1. Blank cells in Table 1 indicate a zero content (the same applies below). The silicone oil is commercially available as a water repellent, and its contact angle, measured using the method described below, was 101°. Spherical fibrous aggregate dried at 110°C for 24 hours was sieved to obtain granular fibrous aggregate with a particle size distribution ranging from 0.425 mm to less than 4.0 mm. The fibrous aggregate was approximately spherical. The granulation binder contained in the fibrous aggregate is powder of sodium carboxymethylcellulose (purity 99.0% or more).

[0049] [Examples 2 to 4, Examples 7 to 11] As shown in Tables 1 to 4, except for changing the mixing ratio of silicone oil, alumina fiber, and sodium carboxymethyl cellulose, the same procedure as in Example 1 was performed to obtain approximately spherical fibrous aggregates with a particle size distribution range of 0.425 mm or more and less than 4.0 mm.

[0050] [Example 5] A roughly spherical fibrous aggregate with a particle size distribution range of 0.425 mm or more and less than 4.0 mm was obtained in the same manner as in Example 1, except that a powder of gum arabic (DSP Gokyo Food & Chemical Co., Ltd., product name: Gum Talha Powder) was used as the granulation binder instead of the powder of sodium carboxymethylcellulose, and the formulation was changed as shown in Table 2.

[0051] [Example 12] A glycol solution containing modified silicone sold as a water repellent was used instead of silicone oil as the silicone resin, and a roughly spherical fibrous aggregate with a particle size distribution range of 0.425 mm or more and less than 4.0 mm was obtained in the same manner as in Example 1, except for changing the formulation as shown in Table 4. Table 4 shows the values ​​converted to mass % of the modified silicone (synthetic resin content) after excluding components other than the modified silicone from the modified silicone / glycol solution. The contact angle of the glycol solution containing the modified silicone, measured by the method described below, was 99°.

[0052] [Example 13] A silicone emulsion sold as a water repellent was used instead of silicone oil as the silicone resin, and a roughly spherical fibrous aggregate with a particle size distribution range of 0.425 mm or more and less than 4.0 mm was obtained in the same manner as in Example 1, except for changing the formulation as shown in Table 4. Table 4 shows the values ​​converted to mass % of silicone from the silicone emulsion, excluding components other than silicone (synthetic resin content). The contact angle of the silicone emulsion, measured using the method described below, was 94°.

[0053] [Example 14] A roughly spherical fibrous aggregate having a particle size distribution range of 0.425 mm or more and less than 4.0 mm was obtained in the same manner as in Example 1, except that rock wool was used as the ceramic fiber instead of alumina fiber and the composition was changed as shown in Table 4. The fiber diameter of the rock wool confirmed under a microscope (magnification 6000x) was 6.1 μm.

[0054] [Example 15] Approximately spherical fibrous aggregates were obtained in the same manner as in Example 4, except that silicone oil was replaced with a fluororesin-based water repellent. The fluororesin-based water repellent used was a commercially available tetrafluoroethylene resin emulsion. Table 6 shows the values ​​converted to mass % of the fluororesin excluding the liquid content. The contact angle of the fluororesin-based water repellent, measured by the method described below, was 91°.

[0055] [Comparative Example 1] A mixture of alumina fiber, powder of sodium carboxymethylcellulose (purity 99.0% or higher), and a small amount of water was rotated along the inner wall of a concrete mixer at room temperature to granulate. The composition of each raw material is as shown in Table 5. The alumina fiber and sodium carboxymethylcellulose were the same as those used in Example 1. The mixture was rotated along the inner wall of the concrete mixer for 30 minutes to granulate. In Comparative Example 1, no silicone resin was used during granulation. A spherical fibrous aggregate dried at 110°C for 24 hours was sieved to obtain a fibrous aggregate with a particle size distribution range of 0.425 mm or more and less than 4.0 mm.

[0056] Comparative Example 2 A fibrous aggregate having a particle size distribution range of 0.425 mm or more and less than 4.0 mm was obtained in the same manner as in Example 1, except that instead of silicone oil, colloidal silica (solid content 20% by mass) and sodium carboxymethyl cellulose were used for granulation in the formulation shown in Table 5. Table 5 shows the values ​​converted to mass % of SiO2 (solid content) from the colloidal silica suspension, excluding components other than SiO2.

[0057] Comparative Example 3 A fibrous aggregate having a particle size distribution range of 0.425 mm or more and less than 4.0 mm was obtained in the same manner as in Example 1, except that mineral oil (Mitsui Seiki Kogyo Co., Ltd. Z6000 compressor oil) was used instead of silicone oil and the formulation was changed as shown in Table 5. Table 5 shows the values ​​converted to % by mass of SiO2 from the colloidal silica suspension, excluding components other than SiO2.

[0058] Comparative Example 4 A mixture of rock wool, sodium carboxymethylcellulose powder, and a small amount of water was granulated by rotating it along the inner wall of a concrete mixer at room temperature. The composition of each raw material is shown in Table 5. The sodium carboxymethylcellulose powder was the same as that used in Example 1. The rock wool was the same as that used in Example 14. The mixture was granulated by rotating it along the inner wall of the concrete mixer for 30 minutes. In Comparative Example 4, no silicone resin was used during granulation. Spherical fibrous aggregate dried at 110°C for 10 minutes was sieved to obtain a fibrous aggregate with a particle size distribution range of 0.425 mm or more and less than 4.0 mm.

[0059] [Table 1]

[0060] [Table 2]

[0061] [Table 3]

[0062] [Table 4]

[0063] [Table 5]

[0064] [Table 6]

[0065] [Measurement of angle of repose] The angle of repose of the fibrous aggregates of each Example and Comparative Example obtained as described above was determined using a tap density measuring instrument, Tap Denser (KYT-5000k), manufactured by Seishin Enterprise Co., Ltd. The conditions for measuring the angle of repose are as follows. The results are shown in Table 1 below. The measurement was performed by dropping the fibrous aggregate from a funnel until it overflowed around the measuring table, and the angle of the hypotenuse of the peak formed at that time was measured. Height of fibrous aggregate drop: 125mm from the bottom of the funnel to the base Diameter of measuring table: 80mm

[0066] [Compressibility Index Measurement] For the fibrous aggregates of each Example and Comparative Example obtained as described above, the tapped bulk density and initial bulk density were measured using a tap density measuring device, Tap Denser (KYT-5000k), manufactured by Seishin Enterprise Co., Ltd., in accordance with the method of 7.1 of JIS R 1628-1997, and the compressibility index (%) was calculated using the formula [1]. The results are shown in Table 1 below. [Formula 1] Compressibility index (%) = [(tapped bulk density - initial bulk density) ÷ tapped bulk density] × 100

[0067] [Measurement of bulk density] The bulk density of the fibrous aggregate of each example was measured based on the tapped bulk density method of JIS R 1628-1997, 7.1. The specific gravity of the aggregate of each example was 0.75 g / cm3, as shown in Tables 1 to 5. 3 It was as follows.

[0068] [Thermal Conductivity] The thermal conductivity was measured in accordance with the "hot wire test" of JIS R 2616-2001. Samples dried at 110°C were used.

[0069] [Spray test] Using the spray gun shown in Figure 1, the fibrous aggregate or the spray material containing the fibrous aggregate of each of the above examples and comparative examples was mixed with a liquid, and the mixture was sprayed onto the plywood board as the workpiece. In the spraying test, a spray gun without a powder supply device between the powder storage section and the connection section was used. Water was used as the liquid.

[0070] As shown in Tables 1 to 6, powder of sodium carboxymethylcellulose (purity 99.0% or higher) or powder of gum arabic (DSP Gokyo Food & Chemical Co., Ltd., product name: Gum Talha Powder) was used as the binder for the spraying material. The particle sizes of sodium carboxymethylcellulose and gum arabic were in the range of 1 to 106 μm.

[0071] For the fibrous aggregate according to Example 9, the fibrous aggregate was stored in the hopper of a spraying machine. For the fibrous aggregate according to each of the Examples and Comparative Examples other than Example 9, a spraying material raw material prepared by mixing each fibrous aggregate with a spraying material binder listed in Tables 1 to 6 was stored.

[0072] Air was supplied to the ejector, and the negative pressure generated by the ejector sucked the raw material for spraying and the fibrous aggregate from the hopper, supplying them into the hollow pipe. The fluidity of the raw material for spraying and the fibrous aggregate when they were supplied from the hopper into the hollow pipe was evaluated according to the following criteria. The fluidity evaluation results are shown in Tables 1 to 6. ◎: The fluidity of the solids is extremely good 〇: Good fluidity of solids △: When 300 kg is sprayed, bridges or rat holes are formed about once, and solids may not be supplied from the hopper. ×: When 300 kg was sprayed, bridges or rat holes were frequently formed, and the solid matter could not be smoothly fed from the hopper.

[0073] Inside the hollow pipe, the spraying material is mixed with the liquid, forming a spraying material that is then sprayed onto the target. The spraying operation begins with the liquid-to-solid mixture ratio optimized in advance. A low liquid content reduces adhesion of the spraying material to the target, resulting in dust generation and rebound. A high liquid content reduces dust generation and rebound, but also reduces dripping and buildup of the spraying material. An appropriate liquid-to-solid mixture ratio eliminates the rebound, dust generation, and dripping problems. The amount of liquid added was optimized to eliminate these problems. Tables 1 through 6 show the optimal amount of water added. The amount of water added was controlled by adjusting the water flow rate using a valve located in the sprayer's liquid supply section.

[0074] [Measurement of added liquid amount] The hollow tube is equipped with a valve for adjusting the flow rate of the liquid. Before opening and closing the valve and conducting the spray test, the flow rate (L / min) of the liquid shared within the hollow tube was measured in advance using a flow sensor. The flow rate of the solids (kg / L) was determined by measuring the mass (kg) of the solids stored in the hopper in advance and measuring the time (min) required for the entire amount of solids to be discharged from the spray machine. The mass of the solids was divided by the time to determine the flow rate of the solids (kg / min). The optimal "amount of water added (%)" was calculated from the flow rates of the liquid and solids using the following [Equation 2]. [Formula 2] Amount of liquid added (times) = Liquid flow rate (kg / min) ÷ Solid flow rate (kg / min) × 100

[0075] [Linear thermal change rate of construction body] The residual linear change rate was measured at 110°C in accordance with JIS R 2554-2005. The material was sprayed onto a 40mm x 40mm x 160mm formwork, dried at 110°C, and then removed from the formwork to prepare test specimens. The latent heat change rate (ΔLe) was calculated using the following formula. The length before drying was measured based on the length of the formwork. The total length of the formwork in the vertical direction was measured at several points using a length meter. To measure the length after drying at 110°C, immediately measure the entire length of the test piece in the longitudinal direction at several points after cooling it to room temperature. ΔLe = (L1 - L0) ÷ L0 × 100 where L0 is the average length (mm) of the formwork before drying, and L1 is the average length (mm) of the test piece after drying.

[0076] [Bulk density of construction body] The bulk density of the applied body was measured in accordance with JIS R 2655-2005, "Test method for bulk density of lightweight castable refractories (method using molded products)." Test specimens were prepared by spraying the material onto a 40mm x 40mm x 160mm formwork, drying at 110°C, and then removing the formwork.

[0077] The thermal conductivity was measured in accordance with the "hot wire test" of JIS R 2616-2001. Samples dried at 110°C were used. [Contact angle evaluation] The contact angle of the water repellent agent used on the fibrous aggregate in the above Examples and Comparative Examples was measured in accordance with JIS R 3257:1999 "Test method for wettability of glass substrate surfaces." Test specimens were prepared by spraying each water repellent agent twice evenly onto a glass preparation from a distance of 20 cm, allowing it to dry, and then subjecting it to testing. The test was performed using the sessile drop method with 2 μl of distilled water (25°C).

[0078] [evaluation] The raw materials for spraying materials and the fibrous aggregates containing the fibrous aggregates of Examples 1 to 15 were superior in fluidity when the solids were supplied from the hopper to the hollow pipe compared to the fibrous aggregate of Comparative Example 1, which did not use a silicone resin, and the solids were supplied smoothly into the hollow pipe without forming ratholes or bridges in the hopper. The fibrous aggregates of Examples 1 to 15 and the fibrous aggregate of Comparative Example 1 were brought into contact with water to check their water absorption, and it was confirmed that the fibrous aggregates of Examples 1 to 15 had lower water absorption than the fibrous aggregate of Comparative Example 1.

[0079] The fibrous aggregate-containing spraying material and fibrous aggregate of Examples 1 to 15 required less liquid to be added and sprayed appropriately onto the substrate compared to Comparative Example 1, which did not use silicone resin. The fibrous aggregate-containing spraying material of Comparative Example 2, which used colloidal silica, and the fibrous aggregate-containing spraying material of Comparative Example 3, which used mineral oil, had excellent fluidity when feeding the solids from the hopper into the hollow pipe, but required more liquid to optimally spray the spraying material onto the substrate.

[0080] The spraying material raw materials containing fibrous aggregate of Examples 1 to 15 had superior fluidity when the solid content was fed from the hopper into the hollow pipe compared to the fibrous aggregate of Comparative Example 4, which did not use silicone resin. The spraying material raw material of Comparative Example 4 had insufficient fluidity in the hopper, and could not be sprayed normally.

[0081] As described above, applying a water repellent to fibrous aggregate improves the fluidity of the raw material for the spraying material containing the fibrous aggregate or the fibrous aggregate, and the amount of liquid required to be added when spraying the spraying material can be reduced compared to when the water repellent is not applied. By reducing the amount of liquid added, the amount of liquid contained in the target body can be reduced. By reducing the amount of liquid added, the amount of voids formed after the liquid evaporates from the target body can be reduced, thereby increasing the strength of the target body. Furthermore, by reducing the amount of liquid contained in the target body, the target body can be made lighter, making it less likely to collapse under its own weight. Although the detailed mechanism by which this effect is realized is unknown, it is presumed that the water-repellent effect of the water repellent agent prevents liquid from penetrating into the fibrous aggregate, making it possible to properly spray the spraying material even when the amount of liquid added is reduced.

[0082] As shown in Tables 1 to 6, the construction bodies formed using the fibrous aggregates of the above examples have a bulk density of 0.6 g / cm 3 It was confirmed that the applied body was porous, lightweight, and had heat retention properties.

[0083] As shown in Tables 1 to 6, it was confirmed that the construction bodies formed using the fibrous aggregates etc. of each of the above examples had a small linear thermal change rate and suppressed dimensional changes.

Claims

1. It is a granular aggregate composed of ceramic fibers. The compressibility index is 35% or less, and the angle of repose is 42° or less, the aggregate comprises a water repellent; A fibrous aggregate for spraying material, the particle size of which is less than 7.0 mm.

2. The bulk density of the fibrous aggregate for spraying is 1.0 g / cm ３ 2. The fibrous aggregate for spraying material according to claim 1, wherein the fibrous aggregate is:

3. A raw material for a spraying material, comprising the fibrous aggregate for a spraying material according to claim 1 or 2 and a binder for a spraying material.

4. The fibrous aggregate for a spraying material according to claim 1 or the raw material for a spraying material according to claim 3 is mixed with a liquid in a conveying air to obtain a spraying material, A spray material application method in which the spray material is sprayed onto the object to be applied from the tip of the discharge part together with a carrier gas.

5. 5. The method for applying a spraying material according to claim 4, wherein the fibrous aggregate for spraying material or the raw material for spraying material is mixed with a liquid component in an amount of 0.6 to 1.5 times the mass of the solid component.

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