JPH1193296A - Foaming inorganic fire resistant covering material, and fire resistant covering construction method of steel frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure an excellent work environment, and improve the working efficiency by including silicate and fine powdery silica, and constituting it by adding a hardening agent, a thicker and a stabilizer thereto. SOLUTION: Silicate of 25 to 75 wt.% in solid content conversion and fine powdery silica of 1 to 40 wt.% are used as a main component, and a foaming inorganic fire resistant covering material is constituted by adding 0.5 to 40 wt.% of a hardening agent, 0.2 to 30 wt.% of a thickner and 0.2 to 15 wt.% of a stabilizer to this. Next, when a using quantity of slicate is smaller than 25%, a foaming height at a fire reduces, and fire resistant performance reduces, and when it exceeds 75%, a softening point of a foaming film reduces, and the fire resistant performance reduces since the foaming film tears and sags when a fire is caused. Next, the foaming inorganic fire resistant covering material is directly applied to a steel frame by trowel application. Therefore, the foaming inorganic fire resistant covering material is a high viscosity paste shape, and does not generate dust at all at an execution work site, and an excellent work environment is secured, and execution work can be performed only by applying it, and the working efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel foamable inorganic refractory coating material for protecting a steel frame of a building from high temperatures in a fire, and a method for refractory coating a steel frame.

[0002]

2. Description of the Related Art Steel frames, which are structural members of buildings, are nonflammable materials. However, when they are exposed to high temperatures due to fire or the like and heated to 450 ° C. or more, the elastic modulus and yield point sharply decrease, and the load increases. It becomes intolerable and deforms. For this purpose, the Building Standards Law stipulates that steel columns and beams in steel buildings should be fire-resistant, and various fire-resistant coating methods are currently being used. In addition, according to the Building Standards Law, the fireproof coating is fire resistant for 1 hour (the furnace temperature is heated to the standard heating temperature of JIS A1304, and after 1 hour, the steel frame temperature is maintained at 350 ° C or less). It is required to have a fire resistance performance of 3 hours, and furthermore, it is required that the refractory coating has an appearance after the test and clears an impact test in which a ball of 5 kg is dropped.

[0003] By the way, fireproof coating materials that have been widely used in the past include sprayed rock wool, sprayed mortar, sprayed gypsum, sprayed silica, and alumina-based.
The one-hour refractory spray thickness of these refractory coatings is 2
0 to 40 mm. In addition, calcium silicate plate, AL
A molded board sticking method of sticking a C board, a PC board, a gypsum board or the like is also widely performed, but the thickness of the one-hour fireproof board is also 20 to 40 mm.

[0004]

As described above, the refractory coating using a spraying material is a low-cost, high-efficiency refractory coating method, but in order to obtain sufficient refractory performance, the spray coating must be thickened. . In addition, the surface of the sprayed refractory material has large irregularities, so that a uniform refractory coating cannot be obtained in terms of quality and lacks aesthetics, and it is difficult to obtain a refractory coating stably fixed to the steel frame surface. In addition, problems in the working environment, such as the scattering of rock wool dust and spray mist, and problems in worker health management due to dust and spray mist adhering and irritating to the skin and inhalation from the oral cavity. In addition, problems such as generation of waste frequently occur, and an urgent solution is strongly demanded. However, there are no measures to prevent dust.

[0005] On the other hand, fireproof coating with a molded plate is performed by cutting a molded plate such as a calcium silicate plate, an ALC plate, a PC plate, or a gypsum plate according to the shape of a steel frame, and pasting it around the steel frame by nailing or the like. It is fixed. Accordingly, a fire-resistant coating having a uniform thickness and excellent fire-resistance performance can be obtained, and the thickness of the edge portion of the H-section steel can be reliably ensured. However, the thickness of the refractory coating layer is not different from the case of the spraying method. However, since a molded plate such as a calcium silicate plate is hard, a large amount of labor is required for the cutting work, and the assembling, nailing, and filling work of the gap of the formed plate are troublesome and workability is increased. There are very bad drawbacks. In addition, transporting a heavy molded plate puts a heavy burden on an operator. Moreover, the fact that dust from the molded plate, dust from the cutting of the molded plate, etc. bothers the operator is no different from the above-mentioned spraying method, and similarly has problems in the working environment and health management. Further, cement boards, gypsum boards, and the like have problems such as cracking and collapse in fire resistance tests.

In recent years, in order to solve the above-mentioned problems, an attempt has been made to apply a foamable fire-resistant paint to a steel frame of a building and use it as a fire-resistant material. Foamable refractory paint
When a fire occurs, a foam layer is formed to delay the temperature rise of the steel frame. Foamable refractory paints consist of a base coat and a top seal. Rust prevention coating is applied to the steel frame, and a base coat is applied to a thickness of 1.0 to 1.5 mm. When heated, the coating film expands and swells by a factor of ten to form a carbonized layer. This provides thermal insulation and protects the steel frame from fire. A top seal is further applied on the base coat to enhance the water resistance and weather resistance of the base coat coating and to give the coating a beautiful appearance.

[0007] These foamable refractory paints are usually composed of a foaming agent, a carbonizing agent, a reaction catalyst, a binder, and a pigment. Phosphoric acid ammonium salts, dicyandiamide, urea, melamine and the like are used as the foaming agent. In addition, polyhydric alcohols and carbohydrates are used as carbonizing agents, phosphoric acid ammonium salts and the like are used as reaction catalysts, and synthetic resin emulsions such as alkyd resins and epoxy resin urethane resins are mainly used as binders.

[0008] Further, foamable fire-resistant paints containing silicate as a main component have been conventionally known. This type of foaming refractory paint utilizes the fact that the hydration water of the silicate is heated to form steam gas and foam. Examples of this type of intumescent refractory paint include, for example, an intumescent refractory paint in which sodium silicate powder having a water content of 41 to 42% is dispersed in a synthetic resin latex (Japanese Patent Publication No. 48-16700).
Foamable refractory paint in which sodium silicate powder is dispersed in an oil paint (Japanese Patent Publication No. 48-16701), and foamable refractory paint containing sodium silicate 1 as a main component (Showa 48-1)
No. 02134), a foamable fire-resistant paint in which water is added to a mixture of powdered sodium silicate and fine metal oxide, aggregate, and air entraining agent (Japanese Patent Publication No. 48-64125). I have.

[0009] However, although the present foamable fire-resistant paints and foamable fire-retardant paints form a foamed heat-insulating layer by heating, they do not satisfy the fire-resistant performance required for building structural parts. That is, the fire resistance performance is such that the allowable steel material temperature is an average of 35 according to JIS A 1304-1975 “Fire Resistance Test Method for Building Structure”.
0 ° C and maximum 450 ° C, and the required fire resistance time is at least 1 according to the Building Standards Law Enforcement Order Article 107.
Although time is required, these performances cannot be satisfied. Further, the strength of the foamed heat insulating layer of the foamable refractory paint is weak, so that it cannot pass the impact test defined in the above test method.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies and as a result, when using finely divided silica in combination with silicate,
The present invention has been completed by finding that the fire resistance is synergistically improved. However, when the silicate and the finely divided silica are mixed, they are solidified within several hours. Therefore, a stabilizer is added to prevent solidification. Depending on the concentration of the stabilizer, solidification is prevented for several days to several months. In addition, solidification means that it becomes impossible to apply because of the thickening of the shape. Further, a curing agent is added to adjust the curing speed to improve the physical properties of the cured film. Further, a thickener is added to secure a required coating thickness. That is, the greatest feature of the present invention is that a silicate and finely divided silica are the main components, and a curing agent, a thickener, and a stabilizer are added thereto.

As the silicate used in the present invention, sodium silicate, sodium metasilicate, potassium silicate, lithium silicate and the like are used alone or in combination. It is known that these silicates have water of hydration, and when heated, the water of hydration gradually separates to form steam gas and foam.
The silicate used in the present invention accounts for 25 to 75% by weight (solid basis, hereinafter the same) of the expandable inorganic refractory coating material.
If the amount used is less than 25%, the foaming height at the time of fire will be low, and the fire resistance will be reduced. If it exceeds 75%, the softening point of the foamed film becomes low, and the foamed film is broken or sagged at the time of fire, resulting in reduced fire resistance. More preferably,
30 to 70% by weight.

The finely divided silica used in the present invention may have a particle diameter of 10 μm or less, preferably 1 μm or less. The finely divided silica is porous, and the smaller the particle diameter, the lower the heat conductivity and the better the heat insulating property. The finely divided silica can be used even if the particle surface has been subjected to a modification treatment such as hydrophobicity, hydrophilicity or water repellency, or a surface treatment. Commercially available finely divided silica includes white carbon produced by a wet method, aerosol fumed silica produced by a dry method, and the like, each of which contains several percent of water. These finely divided silicas are not only used alone,
Two or more kinds may be used in combination.

[0013] When the finely divided silica is used in combination with a silicate, the fire resistance is greatly improved. The proportion of the finely divided silica used is 1 to 40% by weight of the expandable inorganic refractory coating material. If the amount used is less than 1%, almost no synergistic effect is exhibited in fire resistance performance. If it exceeds 40%, the refractory performance does not change but the flexural strength of the refractory coating gradually decreases. More preferably, it is 3 to 30% by weight.

The curing agent used in the present invention includes sodium, potassium, lithium, ammonium, calcium,
Examples include carbonates such as barium and magnesium, bicarbonates, phosphates, metal oxides thereof, and minerals and slag containing these salts and oxides. The amount of the curing agent used is 0.5 to 40% by weight of the foamable inorganic refractory coating material. When the amount is too small, the silicate is not sufficiently cured, and when the amount is too large, the usable time is shortened. More preferably, it is 1 to 35% by weight.
However, in the case where the curing agent is separately mixed and stirred and mixed on site, 15 to 70% by weight may be used.

The thickener used in the present invention is, for example, bentonite, sepiolite, synthetic hectonite and the like. The ratio of the thickener used is 0.2 to 20% by weight of the foamable inorganic refractory coating material. If the amount is too small, the viscosity and thixotropic properties become insufficient. The viscosity of the foaming inorganic refractory coating material is 2,000 to 20,000p
s (25 ° C.). If the viscosity is lower than this, sagging occurs in the vertical part and upper arm of the steel frame, and if it is higher than this, the coating performance by the coating machine deteriorates. In addition, examples of the stabilizer used in the present invention include lithium hydroxide, barium hydroxide, and lithium silicate. As the stabilizer, 0.2 to 15% by weight of the expandable inorganic refractory coating material is used. By increasing or decreasing this amount, the usable time of the expandable inorganic refractory coating material can be adjusted. If no stabilizer is used, the expandable inorganic refractory coating material (a mixture of silicate and finely divided silica) solidifies in several hours. More preferably, it is 0.5 to 13% by weight. In addition, a dispersing agent, a coloring agent, an alkali-resistant glass fiber, or the like may be added as necessary, without any problem.

Next, a method for producing the expandable inorganic refractory coating material of the present invention will be described. No special equipment is required for this production, and a general mixing apparatus such as a mortar mixer or a kneader may be used. First, a predetermined amount of silicate is charged into a mixing device at room temperature, a predetermined amount of a stabilizer and finely divided silica are charged while stirring at a low speed, and when sufficient kneading is completed, a curing agent and a thickener are added. Add and continue stirring until evenly dispersed. The order of addition is not particularly limited, but the above order is desirable from the viewpoint of workability.

The above-mentioned production method is for a one-part foamable inorganic refractory coating material. In this case, the usable time is about two months when stored at room temperature. Usually, this degree of storage is sufficient, but in order to withstand long-term storage, it is sufficient to use a two-part storage agent other than a curing agent. In this case, some or all of the thickener may be added to the curing agent. Then, the two agents are mixed at the construction site. However, there is a trouble and quality problem of bringing a mixing device to the site and stirring and mixing. Further, each agent constituting the foamable inorganic refractory coating material of the present invention may be transported to the site and stirred and mixed at the site, but the labor and quality problems are more difficult than in the case of the two-agent mixture described above. There are many.

Next, a method of applying the foamable inorganic refractory coating material of the present invention will be described. When applying a fire-resistant coating material to a steel frame, an expandable inorganic fire-resistant coating material is directly applied to the steel frame. Application is performed by a method such as trowel coating, mechanical spraying, and mechanical coating. Prior to application, the base (surface) of the steel frame must be free of oil, floating rust, rust preventive paint and the like. Also,
The thickness of the coating depends on the required fire resistance, but if it is fire resistant for one hour, the dry thickness is 8 mm or more (approximately 9 mm or more when applied).
Is preferred. The coated film becomes tack-free in a few hours and cures in a few days. However, it takes about 30 days to dry (air dry). As described above, by applying the foamable inorganic refractory coating material around the steel frame without a seam, a solid refractory coating integrated molding can be obtained.

Such a solid refractory-coated integral product is obtained because silicate, which is a main component of the inorganic coating, reacts with a curing agent and carbon dioxide gas in the air to polymerize silicic acid, Due to the formation of the silicate polymer and a very hard coating. In addition, the inorganic refractory coating used is foamed and ceramicized by a fire test (based on the standard heating temperature of JIS A 1304). After the fire test, the integrally molded product maintains a sufficient shape and strength, and is used for impact tests. It surely withstands.

[0020]

【Example】

(Example 1) In a kneader of SUS-304 material equipped with a stirrer, J sodium silicate No. 1 (manufactured by Nippon Kagaku Kogyo)
50 parts by weight (hereinafter referred to as "parts") of No. 2 sodium silicate N3 (manufactured by Tosoh Sangyo Co., Ltd.) are added, and the mixture is slowly stirred at about 20 rpm. Among them, 3 parts of lithium hydroxide (manufactured by Honjo Chemical) as a stabilizer, 12 parts of white carbon (Zechiol 1100V having a particle diameter of 12 to 20 μm: manufactured by Taki Kagaku), and 22 parts of calcium carbonate (escalon) as a curing agent 1500: Sankyo Seimitsu) and 3 parts of sepiolite (Miraclay LFC-2Z: Omi Mining) as a thickener were gradually added to obtain a thixotropic viscous foamable inorganic refractory coating material. . Its solution viscosity is 3,000 at 25 ° C.
The ps and pot life were about 60 days.

The foamable inorganic refractory coating material is made of a material: SS
-41, a thickness of 8 mm (10 mm at the time of application) was applied to one side of a steel material having a size of 100 × 100 × 6 mm by ironing. After application, the sample was air-dried for 4 weeks and the air-dried state was confirmed. The test specimen was set on the ceiling of a 10 kW electric furnace, and the back surface of the steel material was sufficiently kept warm with a heat insulating material.
The temperature measuring element was set at the center of the back surface (steel material surface) of the applied foamable inorganic refractory coating material. JIS A
The time required for the steel material surface temperature to reach 350 ° C. was determined according to the heating standard curve specified in 1304.
It was 1 minute (60 minutes or more passed). In addition, it confirmed that the fire resistance performance of the test body which stuck the calcium silicate refractory coating board (No. 1: 20 mm) to the said steel plate was 61 minutes. The thickness of the foamed film of the test piece after the fire resistance test was 50 mm. Furthermore, when a 5 kg iron lump was dropped from a height of 1 m onto the foamed specimen surface after the fire resistance test and an impact resistance test was performed, a dent was formed on the specimen surface, but the steel ground was not exposed, and the test passed. Met.

(Embodiment 2) 2
When an agent having a drug property was prepared and measured in the same manner as in the above example, almost the same results were obtained. The main agent of the two agents is
Example 1 except for calcium carbonate (hardening agent)
The mixture was stirred and mixed in the same manner as described above. Then, a mixture obtained by adding 22 parts of calcium carbonate as a curing agent and mixing with stirring was used.

Examples 3 to 20 In the same manner as in Example 1, each of the agents shown in Table 1 was mixed to obtain a foamable inorganic refractory coating material. Table 1 shows the performance in that case. still,
In each of these examples, the thickness (dryness) of the coating film is 8 mm except for two cases. However, depending on the combination of the fire resistance over 60 minutes, the thickness may be smaller than this. For example, in Example 10, when the coating thickness (dry) was 6 mm using the foamable inorganic refractory coating material having the same component ratio as that of Example 9, Example 12 had the same composition ratio as that of Example 11. In this case, the coating thickness was 7 mm with a non-reactive inorganic refractory coating material, and the refractory performance was acceptable.

[Table 1]

As described above, the foamable inorganic refractory coating material of the present invention shown in each of the examples has a refractory performance of 350 ° C. when the coating film thickness is 6 mm or more, especially when the coating thickness is 8 mm. This indicates that the fire resistance was excellent.
Further, even after the fire resistance test, the adhesion between the foamed film and the steel material was strong, the foamed film was also ceramicized and the whole was hard, and all of the impact resistance tests passed.

(Comparative Examples 1 to 8) In each comparative example, almost the same material as in each example was used except that aluminum hydroxide (manufactured by Sumitomo Chemical Co., Ltd.) was used in place of finely divided silica for the purpose of enhancing fire resistance. And produced in a similar manner. as a result,
As shown in Table 2, the coating thickness of the foamable inorganic refractory coating material was 8 m.
At m, none of them reached 60 minutes at 350 ° C. This is because the thickness of the foamed film is smaller than that of the example. On the other hand, the adhesion between the foamed film and the steel material after the fire resistance test is many and strong, and the foamed film is also ceramicized and the whole is hard. However, some of the impact resistance tests failed.

[Table 2]

[0026]

As described above, the foamable inorganic refractory coating material of the present invention exhibits excellent fire resistance when applied to a steel sheet, has excellent adhesion to a steel sheet after a fire resistance test, and has a foamed film. It is hard and can withstand an impact test. The foamable inorganic refractory coating material of the present invention can form a refractory coating for 1 hour on a steel frame if the applied dry thickness is 8 mm or more.

The foamable inorganic refractory coating material of the present invention comprises:
The shape is a paste of high clay, and does not generate any dust, mist, odor, etc. at the construction site, and provides a good working environment. Further, the application is only required to be applied, and no labor or special technique is required, so that it is possible to improve the working efficiency and reduce the cost. Moreover, a seamless integral fire-resistant coating can be formed simply by applying it to a steel frame, so that it exhibits excellent strength. Further, since the thickness of the refractory coating may be small, various excellent effects are exhibited, for example, a living space can be widened.

Claims (4)

[Claims] 1. An expandable inorganic refractory coating material comprising a silicate and a finely divided silica as main components, and a curing agent, a thickener and a stabilizer added thereto. 2. The foamable inorganic refractory coating material according to claim 1, which contains 25 to 75% by weight of silicate in terms of solid content and 1 to 40% by weight of finely divided silica. 3. A hardener of 0.5 to 40% by weight, and 0.2 to 3% by weight.
The foamable inorganic refractory coating material according to claim 1, comprising 0% by weight of a thickener and 0.2 to 15% by weight of a stabilizer. 4. A method for applying a foamable inorganic refractory coating material obtained by adding a finely divided silica, a hardening agent, a thickener, and a stabilizer to a silicate and stirring the mixture to a surface of a steel frame or the like, followed by drying. Characteristic fire-resistant coating method for steel frames.