JP2686833B2 - Refractory coating composition with excellent adhesion to iron - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present application relates to a fireproof coating composition applied to an iron part and having excellent adhesion.

(Prior Art) Conventionally, there have been various materials for coating the iron portion of a building. For example, concrete in reinforced concrete construction, rust-preventive paint for rust prevention of steel columns and beams, and fireproof coating material that protects the steel frame from heat in the event of a fire and maintains its strength.

There are roughly two types of construction methods for this fireproof coating material. One is calcium silicate board gypsum board,
A dry method in which a dry board such as a rock wool board or an asbestos board is attached to a steel frame. The other is an inorganic fiber such as rock wool or asbestos, or a heat-resistant lightweight aggregate such as vermiculite or perlite. Is sprayed together with inorganic binders such as cement or gypsum plaster together with water at the tip of the gun, or they are once kneaded with water in a mixer and sent in paste form with a pressure pump, and sprayed fireproof coating Materials, trowel-coated fireproof coatings that are applied by trowel coating such as cement mortar, and special cases are room-temperature foamed fireproof thermal insulation coatings that form a fireproof coating layer by foaming and curing after coating. There is a wet method such as fireproof paint that expands and expands due to heat and exhibits a fireproof and fireproof effect.

Under such circumstances, the mainstream of the current fireproof coating method is a wet method, which has excellent workability, particularly a spraying method, for steel beams and columns having a relatively complicated shape.

In the wet fireproof coating method, the following conventional fireproof coating methods are mainly used.

1) Set a mortar-concrete formwork around the steel frame, place concrete, lightweight concrete, cellular concrete, etc., or after lathe foundation is applied, mortar or lightweight mortar is troweled. Since these cured products have large heat capacities themselves, they have the property of delaying the transfer of heat from the outside in the event of a fire to the steel frame body, which is consumed by the temperature rise of the coating material. Since such properties are utilized as a fireproof coating material, in order to obtain a sufficient effect, the coating thickness of these coating materials must be increased. Therefore, the weight per unit area becomes heavy, and there is a risk of peeling off mortar and the like. Therefore, the metal lath is usually wound around the steel surface before construction.

2) Rock wool / asbestos type Cotton wool, such as rock wool and asbestos, that contains a large amount of fine air inside, relies on the function of delaying the heat transfer due to its heat insulating property. Therefore, although it is lighter in weight than the material of 1) above, its fireproof coating thickness is thick.

In particular, many of these have extremely weak material strength and adhesion strength, and are liable to peel off, fall off, or be damaged when things come into contact with each other, when there is vibration, or when dew condensation occurs. For this reason, wire mesh is used as the base, but satisfactory results have not been obtained.

The inventors of the present application have continued research and development on wet refractory coating materials for many years, but as a result of further research and development in order to overcome the drawbacks of the above-mentioned materials, synthetic cement for hydraulic cement was obtained. While mixing the resin emulsion powder, aluminum hydroxide powder and 300 ℃ ~ 100
A patent application was previously filed for a refractory composition obtained by blending a specific amount of a carbonate substance that decomposes at 0 ° C. and a lightweight aggregate having open cells of 50% or more. This composition has even better adhesion compared to conventional refractory coating materials.

(Problems to be Solved by the Invention) However, in recent years, market demands have become multifaceted and the performance required for fire-resistant coating materials has become high. That is, the fire-resistant coating material is coated with steel even after heating,
That is, it is required that the steel frame is attached even after heating. In the conventional refractory coating materials, the microscopic adhesive force is originally reduced more and more by heating, and almost no material has the adhesive force up to the current standard temperature of 350 ° C.

In addition, recently, a request to use the refractory composition in the previous application of the inventors of the present application to a part that is always exposed to rain or a part that is completely outdoors, which could not be constructed with a conventional rock wool-based refractory coating material. Is increasing. In order to apply it to such a part, it is necessary to make more intimate contact with the substrate than ever, and there has been a situation in which it cannot be applied to such a part with confidence without improving the adhesion of the refractory composition.

(Method for Solving Problems) The present inventor has worked diligently to solve the above problems, and as a result, an application of an organic acid or an organic acid salt containing at least one carboxyl group and at least one hydroxyl group by the present inventors It has been found that the addition of the above-mentioned refractory composition exhibits the adhesion force several times as high as that of the conventional wet refractory coating material.

Namely, hydraulic cement, synthetic resin emulsion powder, aluminum hydroxide, carbonate substance that decomposes between 300 ° C and 1000 ° C, and lightweight aggregate with open air cells of 50% or more, and carboxyl An organic acid or organic acid salt having at least one or more groups and hydroxyl groups as an active ingredient, and the mixing ratio thereof is: to 100 parts by weight of hydraulic cement, 3 to 50 parts by weight of synthetic resin emulsion powder, 50 to 600 parts by weight of powder in which the weight ratio of the aluminum hydroxide powder and the carbonate substance that decomposes between 300 ° C and 1000 ° C is 15 to 85:85 to 15, and 20 to 300 parts by weight of a lightweight aggregate having a content of 50% or more, 0.01 to 50 parts by weight of an organic acid or organic acid salt having at least one carboxyl group and at least one hydroxyl group, and a mixture containing these components. Kneading , Obtained by drying an excellent refractory coating composition adhesion to iron.

Here, the hydraulic cement used in the present invention is a generally known cement such as Portland cement, alumina cement, lime mixed cement, blast furnace cement, silica cement, fly ash cement, masonry cement, and high sulfate slag cement. Includes. These impart strength to the fireproof coating material.

Next, the synthetic resin emulsion powder is obtained by drying the synthetic resin emulsion obtained by emulsion polymerization in a particle state, and obtained by drying the synthetic resin emulsion obtained by post-emulsification in a particle state. Some of them are easily emulsified when added to water. Usually, a vinyl resin-based synthetic resin emulsion is adjusted to such a form, and acrylic acid ester, versatic acid ester, styrene, vinyl chloride, vinyl acetate and the like can be exemplified as typical substances. Among them, ethylene-vinyl acetate is preferable. Resins based on vinyl acetate and vinyl acetate-vinyl versatate are most preferable because of their good miscibility with hydraulic cement, their excellent workability in actual fire-resistant coating, and their availability as industrial products. The particle size of the powder used is not particularly limited, but generally 60 mesh is used throughout.

In the present invention, the synthetic resin emulsion powder prevents scattering of the lightweight aggregate during construction, improves construction workability, improves adhesion, and prevents peeling of the fireproof coating material under relatively low temperature heating. It also provides various advantages such as maintaining the finishing stability of the decorative finish for a long period of time.

Also, here aluminum hydroxide is Al ₂ O ₃ · x H ₂ O
The value of the hydration degree x differs depending on the production situation or the production method. Examples of natural minerals include boehmite, gibbsite, diaspore, and synthetic aluminum hydroxide produced by the Bayer method or the like. In particular, those with a high degree of hydration, such as givasite, are desirable. The particle size is not particularly limited as long as the maximum diameter is 1 mm or less. Usually, a diameter of 0.3 mm or less is used.

Carbonate substances that divide between 300 ° C and 1000 ° C are heavy calcium carbonate obtained from natural minerals such as limestone, calcite, and marble, light calcium carbonate that is industrially synthesized,
Industrially synthesized light calcium carbonate, magnesite, rhomboidal steel, rhodomanganese steel, dolomite and the like can be specifically exemplified, and heavy calcium carbonate has an advantage that it is inexpensive and easily available. The desirable particle size is not particularly limited as long as it is 1 mm or less.

The mixing ratio of the aluminum hydroxide powder and the carbonate substance is such that the mixture of the aluminum hydroxide powder and the carbonate substance is 10
The ratio in 0 parts by weight must be 15 to 85:85 to 15, and more preferably 20 to 80:80 to 20. In the case of aluminum hydroxide powder alone or carbonate substance alone, it is not possible to achieve the object of the present invention to obtain sufficient refractory performance with a light weight and thin film, and the aluminum hydroxide powder and carbonate substance are specified above. The objects of the present invention can be achieved only when they are mixed in a ratio. And the total weight of these aluminum hydroxide powder and carbonate substance is the hydraulic cement.
It should be 50 to 600 parts by weight with respect to 100 parts by weight.
If it is less than 50 parts by weight, the desired fire resistance cannot be obtained, and if it is more than 600 parts by weight,
The ratio of the hydraulic cement, which is the binder, and the synthetic resin emulsion is relatively small, the strength is reduced, and it becomes difficult to put into practical use.

Next, a lightweight aggregate having 50% or more open cells is a substance formed by foaming or expanding a natural mineral or a synthetic material, and has a particle packing density of 1.2 kg / or less.
Further, the particle size is not particularly limited, but considering the case of using for spraying, it is desirable that the particle size is about 10 mm or less so that the spray nozzle is not clogged. Specifically, in addition to expanded perlite, expanded shale, expanded vermiculite, pumice, etc., silica gel foamed, clay granulated, foamed, etc. A lightweight aggregate that accounts for 50% or more. More preferably, it is preferably composed of a large number of interconnected bubbles and has a low bulk specific gravity (grain packing density of 0.3 kg / or less), and examples thereof include expanded perlite having a pearlite diameter and expanded vermiculite. In addition, even if it is a single-cell or closed-cell lightweight aggregate, it may appear to be open-air cell-like due to breakage or crushing.
It is also possible to use the one that has exceeded the percentage. 50 of these communication bubbles
The content of the lightweight aggregate in the composition is 20 to 300 parts by weight based on 100 parts by weight of the hydraulic cement. If it is less than 20 parts by weight, it is not possible to achieve the weight reduction that is the object of the present invention, and if it exceeds 300 parts by weight, the mechanical strength of the covering material becomes brittle, and the adhesion is poor, and the surface strength is insufficient. It is not preferable because peeling or breakage occurs.

Furthermore, an organic acid or an organic acid salt having at least one or more of a carboxyl group and a hydroxyl group, which are added as a compound necessary for improving the adhesiveness, which is the most important object of the present invention, is gluconic acid or glucone. Sodium acid, calcium gluconate, potassium gluconate, ammonium gluconate, citric acid, sodium citrate,
Calcium citrate, potassium citrate, ammonium citrate, tartaric acid, potassium tartrate, calcium tartrate, sodium tartrate, ammonium tartrate, malic acid, sodium malate, potassium malate, calcium malate, ammonium malate, tannic acid, salicylic acid , Sodium salicylate, calcium salicylate, potassium salicylate, ammonium salicylate, lactic acid, sodium lactate, potassium lactate, calcium lactate,
Examples thereof include ammonium lactate and gluconodeltalactone.

The amount of the organic acid or organic acid salt having at least one or more of a carboxyl group and a hydroxyl group in the composition is 0.0 per 100 parts by weight of the hydraulic cement.
1 to 50 parts by weight. At this time, if it is less than 0.01 parts by weight, the improvement of the adhesive force, which is the object of the present invention, does not appear, and if it is 50 parts by weight or more, the curing slows down, and the adverse effects such as weakening the strength during initial drying are exerted. .

In the present invention, in addition to the above 6 components, powders such as refractory clay, refractory oxide, silica sand, lime, etc. as an extender as required, and glass fiber, rock wool, as a crack preventive for the coating hardened layer, Fibrous substances such as pulp fibers, cellulose-based water-soluble resin powder as a viscosity modifier, a surfactant as a flow modifier, etc. within the range that does not impair the fire resistance performance and does not reduce the mechanical strength or the adhesiveness, It can be mixed in an appropriate amount.

(Action) The action is not clear as to the reason why the composition of the present invention has excellent adhesion to iron, but some chemical reaction occurs between the hydroxyl group on the surface of the steel frame and the organic acid, and further between the organic acid and the emulsion. It is considered that they are chemically bonded and that the two reactions give an adhesion force that has not been considered in the past.

(Examples) Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.

(1) Method for preparing test body After weighing each blended powder, the mixture is kneaded by a mortar mixer to prepare a uniform mixed powder. An appropriate amount of water is added thereto until spraying or trowel coating can be performed, and the mixture is kneaded with a mortar mixer to obtain a mixed paste. A part of the paste is a mold (40 mm × 40 mm × 160 m) specified in JIS A 5210 for measuring bulk density and compressive strength.
m), then cured for 2 days in a curing room at a temperature of 20 ° C and a humidity of 65%, then demolded, and then cured for 26 days in the same manner.
It was cured for a total of 289 days to prepare a test sample.

On the other hand, a hot rolled steel plate (300 mm x 300 mm x 5 mm) with a thickness of 1
It was applied to 0 mm and cured in the same manner as above to obtain a positive adhesive strength test specimen (for normal temperature).

Also, create an adhesion strength test piece in the same manner as above, and heat from the coating material side in a gas furnace based on JIS A 1304 standard heating curve until the temperature of the back surface of the steel plate reaches 350 ° C, and then to room temperature. The one left was used as a test sample for adhesion strength (for after heating).

(2) Bulk Density For the bulk density of the test body, the bulk density test piece cured under the above conditions is measured for the outer dimensions with a caliper to determine the volume (V), and the weight (W) is measured to determine the bulk density. Calculate by the following formula.

(3) Compressive strength The test body of (1) above is used as a 40 mm x 40 mm pressure plate, and the pressure rate is 1 to 2 kg f / sec in principle. The compressive strength is calculated by the following formula from the maximum load when the test piece breaks.

(4) Adhesion strength For adhesion, a 40 mm × 40 mm square tool is attached to the surface with epoxy resin, a tensile test is performed at a load speed of 150 to 200 kg f / min, and the maximum load until breakage is measured. The adhesion strength was calculated from the following formula.

Table 1 shows each component used in each example.
Table 2 shows an example prepared by using them, and Table 3 shows a comparative example.

(Example 1) When the physical properties of the test body obtained from the composition of Table 2 were measured, the bulk density was 0.70 g / cm ³ , the compression strength was 31 kg f / cm ² ,
Adhesive strength at room temperature 3.0 kg f / cm ² , adhesive strength after heating 0.8 kg
After heating at f / cm ² , the adhesive strength was maintained and peeling did not occur.

(Example 2) Physical properties were measured in the same manner as in Example 1 except that sodium gluconate was used in citric acid.
0.70 g / cm ³ , compressive strength 23 kg f / cm ² , adhesive strength at room temperature 3.1
kg f / cm ² , the adhesive strength after heating was 0.6 kg f / cm ^2, and the adhesive strength was maintained even after heating and peeling did not occur.

(Example 3) Various physical properties were measured in the same manner as in Example 1 except that sodium gluconate was replaced with calcium tartrate.
Bulk density 0.70 g / cm ³ , compressive strength 34 kg f / cm ² , adhesive strength at room temperature 3.0 kg f / cm ² , adhesive strength after heating 0.8 kg f / cm ² No peeling occurred.

(Example 4) Physical properties were measured in the same manner as in Example 1 except that sodium gluconate was replaced with tannic acid.
0.70 g / cm ³ , compressive strength 35 kg f / cm ² , adhesive strength at room temperature 2.7
kg f / cm ² , the adhesive strength after heating was 0.7 kg f / cm ^2, and the adhesive strength was maintained even after heating and peeling did not occur.

(Comparative Example 1) Various physical properties were measured in the same manner as in Example 1 except that sodium gluconate was removed, and a bulk density of 0.71 g / cm ³ ,
The compressive strength was 34 kg f / cm ² , and the adhesive strength at room temperature was 2.2 kg f / cm ² , and the adhesive strength after heating could not be measured due to peeling.

(Comparative Example 2) The physical properties of the wet rock wool fireproof coating material shown in Table 3 were measured, and the bulk density was 0.53 g / cm 3.
^3. Compressive strength 4kg f / cm ² The adhesive strength at room temperature was so small that it could not be measured, and the adhesive strength after heating could not be measured due to peeling.

(Comparative Example 3) Various physical properties were measured in the same manner as in Example 1 except that sodium molybdate was used instead of sodium gluconate. Bulk density was 0.71 g / cm ³ , compression strength was 32 kg f / cm ² , and room temperature was measured. The adhesive strength of is 2.0 kg f / cm ² and the adhesive strength after heating is
Measurement was impossible due to peeling.

(Comparative Example 4) Physical properties were measured in the same manner except that the sodium gluconate of Example 1 was used in an amount of 0.005 parts by weight, which is less than the content of the present invention, and a bulk density of 0.70 g / cm ³ and a compressive strength were obtained. 33 kg f / cm ² The adhesive strength at room temperature was 2.2 kg f / cm ² , and the adhesive strength after heating could not be measured due to peeling.

Comparative Example 5 Various physical properties were measured in the same manner as in Example 1 except that sodium succinate having no hydroxyl group was used as sodium gluconate, and a bulk density of 0.71 g / cm ³ and a compressive strength of 31 kg f / cm ³ The adhesion strength at room temperature was 2.1 kg f / cm ² , and the adhesion strength after heating could not be measured due to peeling.

(Effects) FIG. 1 shows a comparison between room temperature adhesive strength and adhesive strength after heating. As can be seen from the above, the composition of the present invention has such an adhesiveness that it does not peel off from the iron part after heating at 350 ° C. According to the present invention, not only will it be able to withstand use under more severe conditions, but peeling, falling, damage, etc. after construction will be reduced, and even if a mechanical shock is applied, conventional fireproof coating The material that had peeled off became more difficult to peel off. Then, even when a fire occurs, the conventional fireproof coating material is easily peeled off under heating or after heating, but becomes difficult to peel off.

[Brief description of the drawings]

FIG. 1 shows a comparison between room temperature adhesive strength and heated adhesive strength.

Continuation of the front page (72) Inventor Takeshi Fujiwara 4-5 Minamishimizu-cho, Ibaraki-shi, Osaka Shirokuni Kenken Kogyo Co., Ltd. Examiner Hiroshi Josho (56) References JP 59-146984 (JP, A) Japanese Patent Laid-Open No. 2-311379 (JP, A) International Publication 88/2740 (WO, A1)

Claims (1)

(57) [Claims] 1. A hydraulic cement, a synthetic resin emulsion powder, aluminum hydroxide, a carbonate substance that decomposes between 300 ° C. and 1000 ° C., and a lightweight aggregate having 50% or more open air cells.・ At least 1 for each of the carboxyl and hydroxyl groups
With one or more organic acids or organic acid salts as the active ingredient,
The blending ratio is: to 100 parts by weight of hydraulic cement, 3 to 50 parts by weight of emulsion powder, and 15 to 15 parts by weight of aluminum hydroxide powder and a carbonate substance that decomposes between 300 ° C and 1000 ° C. 50-600 parts by weight of powder mixed in a ratio of ~ 85: 85-15, 20-300 parts by weight of lightweight aggregate having 50% or more of open cells, and at least carboxyl group and hydroxyl group, respectively. A composition having 0.01 to 50 parts by weight of an organic acid or an organic acid salt having one or more components, obtained by hydro-kneading a mixture containing these components and drying the mixture and having excellent adhesion to iron.