Inorganic coating material

Abstract

To provide a technology that can suppress the precipitation of needle-like crystals generated in the curing process, i.e., to provide an inorganic binder and an inorganic coating material by the technology.MEANS: An inorganic coating material of the invention is mainly composed of a specific inorganic binder and inorganic fibers, and the content ratio of components in the inorganic binder is within a specific range. The inorganic binder contains alkali silicate, gypsum, inorganic powder containing SiO2 other than cement and alkali silicate, and water, and the ratio (G / M2O) of the mass (G) of gypsum to the mass (M2O) of the contained alkali in terms of oxide is in a specified range. Suitably, the inorganic fiber is rock wool.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an inorganic binder. Specifically, it relates to an inorganic binder capable of suppressing the formation of acicular crystals during the curing process. Further, the present invention relates to an inorganic coating material. Specifically, it relates to an inorganic coating material capable of suppressing the formation of acicular crystals during the curing process.

Background Art

[0002] For the purpose of imparting fire resistance, fireproofness, sound absorption, heat insulation, etc. to members of a structure, spraying materials such as sprayed rock wool materials composed of fibers such as rock wool and binders such as cement paste are sprayed. A typical sprayed rock wool material, which is a representative of this sprayed material, is composed of rock wool, cement, and water, and is widely used because it is excellent in terms of fire resistance, workability, etc. (see, for example, Patent Document 1). Cement is an inexpensive and excellent inorganic binder, but since it is manufactured by decomposing limestone, a raw material, at a high temperature and further reacting it with silicon dioxide raw materials, aluminum oxide raw materials, iron oxide raw materials, etc. at a high temperature, a large amount of carbon dioxide, which is a representative of greenhouse gases, is generated during manufacturing. For this reason, sprayed materials using inorganic binders that do not contain cement as the main component and inorganic binders therefor are desired.

[0003] It has been disclosed that silicates, alkali silicates (for example, water glass), geopolymers, colloidal silica, or colloidal alumina can be used as binders for rock wool fibers (rock wool) with a specific composition (see, for example, Patent Document 2).

[0004] By the way, when a binder is sprayed onto fibers and merged to form a sprayed material layer as a sprayed material, there is a technique of spraying the binder together with pressurized air (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] When an inorganic binder containing, in addition to alkali silicate, cement and SiO2-containing inorganic powder other than alkali silicate as an inorganic binder other than cement is sprayed together with rock wool to form a sprayed material layer (coating material layer) made of a rock wool composition and various studies are conducted, it has been found that acicular crystals may precipitate on the surface of the sprayed material layer to such an extent that they can be visually confirmed during the curing process of the sprayed material layer. The present invention aims to provide a technique capable of suppressing the precipitation of acicular crystals generated during the curing process, that is, to provide an inorganic binder and an inorganic coating material.

Means for Solving the Problems

[0007] The present invention has found that the above problems can be solved by using a specific inorganic binder and inorganic fiber as main components and setting the content ratio of the components contained in the inorganic binder within a specific range, and has completed the present invention. That is, the present invention provides the following (1) to (4). (1) An inorganic binder containing alkali silicate, gypsum, SiO2-containing inorganic powder other than cement and alkali silicate, and water, wherein the ratio (G / M2O) of the mass (G) of gypsum to the mass (M2O) of the alkali in terms of oxide conversion contained is 0.1 to 4.0, and used as a binder for fiber spraying An inorganic coating material mainly composed of an inorganic fiber and . (2) The inorganic substance of (1) above, wherein the ratio (G / M2O) of the mass (G) of gypsum to the mass (M2O) of the alkali in terms of oxide conversion contained is 0.2 to 2.0 Coating material . (3) The inorganic fiber is rock wool The inorganic substance of (1) or (2) above Coating material.

Effects of the Invention

[0008] According to the present invention, in the curing process of a spraying material layer (coating layer) mainly composed of an inorganic binder not containing cement and inorganic fibers, an inorganic binder can be obtained that can suppress the generation and precipitation of acicular crystals on the surface of the spraying material layer to such an extent that they can be visually confirmed. According to the present invention, in the curing process, an inorganic coating material mainly composed of an inorganic binder not containing cement and inorganic fibers can be obtained that can suppress the generation and precipitation of acicular crystals on the surface of the spraying material layer (coating layer) to such an extent that they can be visually confirmed. In addition, since the binder and inorganic fibers used in the present invention do not contain cement as a main component, the amount of carbon dioxide emissions during the production of raw materials is less than that when cement is used as the raw material of the binder.

Embodiments for Carrying Out the Invention

[0009] The inorganic binder of the present invention contains an alkali silicate, gypsum, "SiO2-containing inorganic powder other than cement and alkali silicate", and water, and is characterized in that the ratio (G / M2O) of the mass (G) of gypsum to the mass (M2O) of the contained alkali in terms of oxide is 0.1 to 4.0. Here, when the content of alkali contained in the components other than alkali silicate is small (2% by mass or less), since it is extremely small compared to the mass of alkali in the alkali silicate, the mass of alkali contained in the component can be ignored.

[0010] As the gypsum used in the present invention, anhydrite is preferable because it is easy to obtain the fluidity and pot life of the inorganic binder. Also, the gypsum to be used may be a powder with a particle size of 0.5 mm or less, preferably having a Blaine specific surface area of 2000 cm 2 / g or more is preferable because of its high reactivity, and more preferably, those having a Blaine specific surface area of 3000 to 20000 cm 2 / g are even more preferable.

[0011] When the ratio (G / M2O) of the mass (G) of gypsum to the mass (M2O) of the oxide of alkali contained in the inorganic binder of the present invention, in terms of mass, is less than 0.1, the generation and precipitation of acicular crystals occurring during the curing process of the sprayed material layer (coating material layer) composed of the rock wool composition formed by spraying the inorganic binder together with rock wool cannot be sufficiently suppressed. Further, when G / M2O exceeds 4.0, the fluidity of the inorganic binder decreases or the pot life is too short, and the sprayed material layer (coating material layer) cannot be formed by spraying. Since it is easy to obtain the fluidity and pot life that enable the formation of the sprayed material layer (coating material layer) by spraying, it is preferable that G / M2O is 0.2 to 3.8, and since a pot life of 120 minutes or more can be obtained, it is more preferable that G / M2O is 0.2 to 2.0.

[0012] In the present invention, it is preferable that the gypsum is 0.5 to 40% by mass, more preferably 2 to 20% by mass, based on the mass of the "SiO2-containing inorganic powder other than cement and alkali silicate".

[0013] As the alkali silicate used in the present invention, it is preferable to use one kind selected from sodium silicate such as sodium metasilicate and sodium orthosilicate, or an aqueous solution of sodium silicate such as water glass, lithium silicate or an aqueous solution of lithium silicate, potassium silicate or an aqueous solution of potassium silicate, or two or more of these. More preferably, one kind selected from sodium silicate or an aqueous solution of sodium silicate, or two or more of these are used.

[0014] The "SiO2-containing inorganic powder other than cement and alkali silicate" used in the present invention (hereinafter sometimes referred to as "SiO2-containing inorganic powder") refers to an inorganic powder containing SiO2 as the main chemical composition other than cement and alkali silicate. For example, blast furnace slag powder, fly ash, metakaolin, silica fume, volcanic ash, igneous rock powder, powder of fired igneous rock, powder of fired sewage sludge slag, powder of molten municipal waste slag, etc. are preferable examples. As the SiO2-containing inorganic powder, the Blaine specific surface area is 2000 cm 2Those with a value of / g or more are preferred because the binder cures quickly, and more preferably those with a value of 2500 cm 2 / g or more are used. Further, as the upper limit value of the Blaine specific surface area of the SiO2-containing inorganic powder used in the present invention, since the time for maintaining the fluidity of the binder can be lengthened, 12000 cm 2 / g or less is preferable, and more preferably 10000 cm 2 / g or less.

[0015] The inorganic binder of the present invention contains an alkali silicate, "an SiO2-containing inorganic powder other than cement and alkali silicate", and water, and the water content is preferably 50% by mass or more. Here, the water content (C W ) of the water contained in the inorganic binder of the present invention is the mass (M W ) of the water contained in the inorganic binder of the present invention divided by the mass (M B ) of the inorganic binder, expressed as a percentage as shown in the following formula (1). At this time, for the mass (M W ) of the water contained in the inorganic binder, if it is negligibly small like the mass of the water contained in the SiO2-containing inorganic powder due to the influence of moisture in the atmosphere, it is not necessary to consider this.

[0016] C W (%) = M W ÷M B ×100 ···· (1)

[0017] When the water content (C W ) of the water contained in the inorganic binder of the present invention is 50% by mass or more, the binder can be sprayed using the spraying device used for spray-applied rock wool by the semi-dry method without using compressed air for spraying the binder, and it can be merged with fibers such as rock wool to form a homogeneous sprayed material layer. Here, homogeneous means that when the fibers used for spraying are in the form of lumps (granular) like the rock wool (rock wool granular cotton) used for spray-applied rock wool, the binder is almost evenly attached to the surface of the fiber lump and partially penetrates into the fiber lump, and the binder exists between the fiber lumps. The water content (C W) is preferably 60 mass% or more because it is easier to obtain high fluidity of the inorganic binder, more preferably 60 to 96 mass%, and most preferably 75 to 90 mass% because the amount of dust generated during spraying construction is small and it is difficult for the inorganic binder to drip (liquid dripping) from the sprayed inorganic coating material layer.

[0018] The inorganic binder of the present invention is used as a binder for fiber spraying. Here, the fiber is not particularly limited as long as it can be sprayed together with the binder. For example, cotton-like fibers such as rock wool (including slag wool), glass wool, and ceramic wool are suitable examples.

[0019] An alkali hydroxide such as sodium hydroxide, potassium hydroxide, or lithium hydroxide or an aqueous solution thereof may be added to the inorganic binder of the present invention.

[0020] The inorganic binder of the present invention is an inorganic binder containing an alkali silicate, "SiO2-containing inorganic powder other than cement and alkali silicate", and water as main components. In addition to these, other inorganic components and organic components may be contained. As this other inorganic component, cement may be contained in an amount of 10 mass% or less based on the mass of the SiO2-containing inorganic powder. In this case, the cement mainly acts as a stimulant for the SiO2-containing inorganic powder. Since the amount of carbon dioxide generated during the production of the raw materials is small, it is more preferable that the content ratio of cement in the binder for fiber spraying of the present invention is 5 mass% or less based on the mass of the SiO2-containing inorganic powder, and even more preferably 2 mass% or less.

[0021] The inorganic coating material of the present invention mainly comprises the above inorganic binder and inorganic fibers. The inorganic fibers in the present invention are not particularly limited as long as they can be sprayed together with the inorganic binder. For example, cotton-like fibers such as rock wool, glass wool, and ceramic wool are preferable in terms of fire resistance, fireproofness, sound absorption, or heat insulation. Since they are incombustible and do not generate rust, rock wool, glass wool, or ceramic wool is more preferable, and rock wool is most preferable in terms of stability with the binder. In the present invention, rock wool is a material mainly composed of melted rock, blast furnace slag, etc. in a melting furnace, which is a material (mineral fiber) that is fiberized while being rapidly cooled. For example, slag wool produced from a material mainly composed of blast furnace slag is also included.

[0022] The inorganic coating material (rock wool coating material) of the present invention may contain, within a range not impairing the effects of the present invention, materials other than the above components, for example, various admixtures for cement, mortar, or concrete containing alkali metal salts such as sodium carbonate and sodium sulfate, other than the above, and other components (additives).

[0023] The inorganic coating material (rock wool coating material) of the present invention is preferably manufactured by a spraying method similar to the semi-dry method in the rock wool spraying method. In this case, instead of the cement paste in the rock wool spraying method of the semi-dry method, the above inorganic binder is used, and when the inorganic fiber is other than rock wool, the inorganic fiber is used instead of rock wool. The inorganic fiber (rock wool) pumped in the pumping hose is discharged from the discharge port of the spraying nozzle communicating with the pumping hose, and the above inorganic binder is sprayed thereon, whereby the inorganic coating material of the present invention composed of a rock wool composition can be manufactured.

[0024] The inorganic coating material (rock wool coating material) of the present invention can be used as an alternative to a rock wool composition (sprayed rock wool) mainly composed of rock wool and cement paste. That is, it can be used as a refractory coating material, a sound-absorbing coating material (sound-absorbing material), or a heat-insulating coating material (heat-insulating material, heat-preserving material). In particular, when the contained fiber is rock wool, glass wool, or ceramic wool, since the inorganic coating material of the present invention does not contain a combustible material as a main component, it can be made into a non-combustible coating material by suppressing the content of the combustible material or not containing the combustible material.

Example

[0025] [Example 1] Using an alkali silicate, gypsum, "inorganic powder containing SiO2 other than cement and alkali silicate", and water, an inorganic binder for fiber spraying was prepared at the mixing ratios shown in Table 1. The materials used are shown below. "%" in Table 1 means "mass %".

[0026] <Materials Used> (1) Alkali silicate: No. 3 water glass (SiO2; 28.93 mass%, Na2O; 9.34 mass%, H2O; 61.73 mass%), symbol; WG3 (2) Inorganic powder containing SiO2 other than cement and alkali silicate: Blast furnace slag powder (blast furnace slag fine powder 4000, Blaine specific surface area; 4130 cm 2 / g), symbol; BSF (3) Gypsum: Anhydrite (particle size; 0.2 mm or less and Blaine specific surface area of 7000 cm 2 / g of powder), symbol; GY (4) Water: Raw water in Sakura City

[0027]

Table 1

[0028] Regarding the prepared inorganic binder, the following evaluation tests were conducted, and the results are shown in Table 2. <Flowability Test> Immediately after preparation and 120 minutes after preparation, the mixture was stirred, and using a device commonly used in the semi-dry spraying method of rock wool spraying material, it was confirmed whether the prepared inorganic binder had a fluidity sufficient for spraying instead of cement slurry. When it had a fluidity sufficient for spraying, it was evaluated as "good" (symbol: ○), and when it did not have a fluidity sufficient for spraying, it was evaluated as "bad" (symbol: ×).

[0029] <Spraying Test> The prepared inorganic binder was used together with rock wool (granular wool, manufactured by Pacific Materials Co., Ltd.) using an apparatus commonly used in the spraying method of the semi-dry method of rock wool spraying material, and was sprayed from a spraying gun (nozzle), and sprayed inside a container (inner dimensions: 20 (cm) × 20 (cm) × 5 (cm)) to form an inorganic coating material layer composed of an inorganic coating material (rock wool coating material), and cured for 1 month in a constant temperature room at 20 °C and 60% RH. Thereafter, the surface of the inorganic coating material layer was visually confirmed, and when acicular crystals were not deposited, it was evaluated as "good" (symbol: ○), and when acicular crystals were deposited, it was evaluated as "bad" (symbol: ×).

[0030]

Table 2

[0031] For the inorganic binders of Blending Nos. 2 to 8 corresponding to the examples of the present invention, in each case, using an apparatus commonly used in the spraying method of the semi-dry method of rock wool spraying material, they were sprayed from the injection port for cement paste of the spraying gun instead of cement paste, and at the same time, the inorganic coating materials formed by merging and mixing with the rock wool sprayed from the spraying gun did not show the formation and precipitation of acicular crystals even after curing for 1 month. Also, the dust generated during spraying construction was less than the dust generated during spraying construction by the spraying method of the semi-dry method using cement paste.

[0032] On the other hand, for the inorganic coating materials formed in the same manner as the inorganic binders of Blending Nos. 2 to 8 using the inorganic binder of Blending No. 1 in which the ratio (G / M2O) of the mass (G) of gypsum to the mass (M2O) of the alkali oxide in the inorganic binder is less than 0.1, the formation and precipitation of acicular crystals were observed even after curing for 1 month. However, the dust generated when spraying construction was carried out using the inorganic binder of Blending No. 1 was less than the dust generated during spraying construction by the spraying method of the semi-dry method using cement paste, similar to when using the inorganic binders of Blending Nos. 2 to 8.

[0033] In addition, for the inorganic binders of Mixing Nos. 2 to 6 where the ratio (G / M2O) of the mass (G) of gypsum to the mass (M2O) of the alkali in terms of oxide of the inorganic binder is 0.2 to 2.0, all of them had fluidity that allowed the formation of the coating material layer by spraying even after 120 minutes, and could ensure a pot life of 120 minutes, which was extremely excellent. In contrast, the inorganic binders of Mixing Nos. 7 and 8 had pot lives of 90 minutes and 80 minutes respectively, which were excellent with a pot life of 60 minutes or more, but were inferior to the inorganic binders of Mixing Nos. 2 to 6.

Industrial Applicability

[0034] The present invention can be suitably used, for example, in inorganic coating materials that impart properties such as fire resistance, fireproofing, sound absorption, or heat insulation.

Claims

1. An alkali silicate, gypsum, an inorganic powder containing cement and SiO other than the alkali silicate, and water are contained. ２ ​ The ratio (G / M 2 O) of the mass (G) of gypsum to the mass (M 2 O) of the oxide-converted alkali contained is 0.1 to 4.0, and an inorganic coating material mainly composed of an inorganic binder used as a binder for fiber spraying and inorganic fibers.

2. The ratio (G / M 2 O) of the mass (G) of gypsum to the mass (M 2 O) of the alkali contained in terms of oxide is 0.2 to 2.0, and the inorganic coating material according to claim 1.

3. The inorganic coating material according to Claim 1 or 2, wherein the inorganic fiber is rock wool.

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