JP2013136490A - Treatment method for preventing scattering of inorganic fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment technique for preventing scattering of inorganic fibers, which is useful for a wet sprayed refractory covering material that is rigid and less permeable to liquid or a molded plate refractory covering material that is rigid and less permeable to liquid to reliably keep inorganic fibers (particularly, asbestos) contained in the refractory covering material.SOLUTION: In the treatment method for preventing scattering of inorganic fibers in which a penetrant 30 is impregnated into a surface of a refractory covering material 10 containing inorganic fibers, the impregnated penetrant 30 is solidified, and the surface is further coated with a flame retardant coating material 40 to prevent scattering of the inorganic fibers from the refractory covering material 10, an excess of the penetrant 30 not penetrating into the refractory covering material 10 that is a wet sprayed refractory covering material remains on the surface of the refractory covering material 10 and covers the surface in such a way as to cover granules 20 sticking to the surface of the refractory covering material 10, so that the penetrant 30 and the flame retardant coating material 40 come in surface contact with each other.

Description

  The present invention prevents inorganic fibers, particularly asbestos, from scattering from wet-sprayed fire-resistant coating materials or molded board fire-resistant coating materials containing inorganic fibers, particularly asbestos.

  As a technique for preventing the asbestos from scattering, a dry spray material containing a large amount of asbestos has generally been subjected to a method of spraying and solidifying a drug on the surface (Patent Document 1, etc.). In the case of a dry-type fireproof coating material, the density is low and the scum is low, so even if a flammable organic material that is very easy to permeate is used, it can easily penetrate and solidify over the entire spray thickness even in a small amount. And since the ratio with the asbestos which is an inorganic material becomes very low, even if it was an organic material, there was no problem arising from fire resistance.

  Patent Document 2 discloses a treatment method for preventing asbestos dusting by impregnating an asbestos board, which is a molded board fireproof covering material, with an aqueous polyvinyl alcohol solution.

Japanese Patent Laid-Open No. 2-48484 JP-A-64-42376

Asbestos spraying techniques that have been used as fireproof coating materials for buildings and the like are roughly classified into “dry spraying” and “wet spraying”. Patent Document 1 described above relates to “dry spraying”.
On the other hand, asbestos scattering prevention technology for “wet spraying” has hardly been established so far (“dry spraying” has a long history, and it was highly necessary to deal with the dismantling of buildings) In the case of "wet spraying" and "molded board fireproof coating material", the surface is remarkably hard compared to "dry spraying", so the conventional sealing method (technology) ) Cannot be applied as is.

  Therefore, the present invention has been made in view of such circumstances, and is a wet spray refractory coating material that is extremely hard and difficult to penetrate liquids compared to “dry spraying” or a molded board that is also hard and difficult to penetrate liquids. An object of the present invention is to provide an inorganic fiber scattering prevention technique that is excellent in reliably containing inorganic fibers (especially asbestos) contained in a fireproof covering material.

The inorganic fiber scattering prevention treatment technology of the present invention ensures the containment effect of inorganic fibers (for example, asbestos) contained in wet spray fire-resistant coating materials or molded board fire-resistant coating materials different from conventional (dry spray). It is a processing technique that can be made.
Here, the “fireproof covering material” is mainly used for fireproof covering of a frame such as a steel beam or a column, but is not limited thereto.
The “inorganic fiber” is an inorganic fiber contained in a wet spray fireproof covering material or a molded board fireproof covering material, and includes rock wool and glass wool in addition to asbestos.

The first invention of the present invention is a wet-fired fire-resistant coating material or a fire-resistant coating material that is a molded board fire-resistant coating material that contains inorganic fibers. In the inorganic fiber scattering prevention treatment method for preventing the scattering of inorganic fibers from the fireproof coating material by coating with the coating material, a penetrant that cannot penetrate into the inside of the fireproof coating material is a surface of the fireproof coating material. It covers the particulate matter that remains on the surface of the fire-resistant coating material or the irregularities formed on the surface, and the penetrant and the flame-retardant coating material are in surface contact. It is.
The second invention is the same inorganic material characterized in that polyvinyl alcohol having a polymerization degree of 500 to 2000, a saponification degree of 70 to 95 mol%, a solution concentration of 1 to 8%, and a solution viscosity of 5 to 500 cP is used as the penetrant. This is a fiber scattering prevention treatment method.
According to a third aspect of the present invention, the inorganic fiber is characterized in that the flame retardant coating material contains a synthetic resin emulsion containing a solid content of 35 wt% to 80 wt%, a flame retardant, and an inorganic filler. This is a scattering prevention treatment method.

As for polyvinyl alcohol, when the degree of polymerization is less than 500, the strength of the solidified penetrant becomes weak, and when it exceeds 2000, the solution viscosity of polyvinyl alcohol exceeds 500 cp, making it difficult for the penetrant to penetrate. Preferably, the degree of polymerization is 1700-2000.
If the degree of saponification is less than 70, the strength of the solidified penetrant becomes weak, and if it exceeds 95, the solution viscosity of polyvinyl alcohol exceeds 500 cp, making it difficult for the penetrant to penetrate. The saponification degree is preferably 80 to 95 mol%.
Furthermore, when the solution concentration is less than 1%, the strength of the solidified penetrant becomes weak, and when the solution concentration exceeds 8%, the solution viscosity of polyvinyl alcohol exceeds 500 cp, so that the penetrant hardly penetrates. Preferably, the solution concentration is 3 to 5%.
In addition, when the solution viscosity is less than 5 cp, the strength of the solidified penetrant becomes weak, and when the degree of polymerization exceeds 2000, the solution viscosity of polyvinyl alcohol exceeds 500 cp, making it difficult for the penetrant to penetrate.

As the inorganic filler constituting the “flame retardant coating material”, titanium dioxide, and as the flame retardant, one or a combination of two or more powders of calcium sulfate, aluminum hydroxide, magnesium hydroxide, etc. Is preferred.
Here, among the flame retardants, the metal hydroxide is dehydrated and decomposed when heated, and has an effect of suppressing the temperature rise due to the endotherm at that time. Aluminum hydroxide has a dehydration temperature of about 300 °. Since C and magnesium hydroxide have a dehydration temperature of about 380 ° C., when both are used in combination, dehydration decomposition proceeds in two stages, and the temperature rises between 300 to 400 ° C. at which the synthetic resin begins to burn. The suppression effect lasts longer and is more reliable. As a result, the fireproof performance is improved.
About the ratio of the content which comprises a "flame-retardant coating material", it is preferable to set it as 5-20 weight% of synthetic resin emulsions, 20-60 weight% of flame retardants, and 5-60 weight% of inorganic fillers.

The present invention has the following effects.
(1) A fireproof coating is obtained by infiltrating and solidifying a penetrant on the surface of a wet spray type or molded plate type fireproof coating material containing inorganic fibers, and further coating the surface with a flame retardant coating material. The material is protected twice, and the scattering of inorganic fibers from the fireproof coating can be reliably prevented. That is, a penetrant that cannot penetrate into the inside of the fireproof coating material remains on the surface of the fireproof coating material, and covers the granular material adhering to the surface of the fireproof coating material or the unevenness formed on the surface. The surface contact between the penetrant and the flame retardant coating material improves the adhesion between the flame retardant coating material and the surface of the fireproof coating (primer effect), and the penetrant is a flame retardant coating. It serves as an anchor for the material (anchor effect) and can reliably cover the surface of the fireproof coating. In other words, the coating adheres firmly to the adherend and is not easily damaged by physical impact such as collision due to moderate flexibility.
(2) As a penetrant, a wet blow that is hard and difficult to permeate liquid by using polyvinyl alcohol having a polymerization degree of 500 to 2000, a saponification degree of 70 to 95 degree, a solution concentration of 1 to 8%, and a solution viscosity of 5 to 500 cP. By penetrating and solidifying the fire-resistant coating material of the attached mold or the mold plate type, inorganic fibers (for example, asbestos) contained in the fire-resistant coating material can be reliably contained (restrained).
(3) Since the flame-retardant coating material contains a synthetic resin emulsion, a flame retardant, and an inorganic filler, the surface of the fire-resistant coating material can be reliably protected with excellent strength and weather resistance of the formed coating film. At the same time, it is possible to prevent the generation of a large amount of smoke and harmful gases during a fire.
(4) The flame-retardant coating material can form a coating film (protective film) having an appropriate thickness on the surface of the fireproof coating material by containing a solid content of 35 wt% to 80 wt%.

Explanatory drawing which shows embodiment of this invention (A: There is no penetrant, B: There exists a penetrant). (A) Structural view of test apparatus (b) Cross section of test body A (c) Cross section of test body B (A) The figure which shows the test result of an inorganic fiber scattering prevention process (b) The figure which shows the test result of durability

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 illustrates an inorganic fiber scattering prevention treatment structure of the present invention.
As shown in FIG. 1 (A) and FIG. 1 (B), a wet spray fire-resistant coating material 10 (hereinafter referred to as “fire-resistant coating material 10”) which is hard and does not easily penetrate liquid into a frame (not shown) such as a steel beam or a column. Is covered).
FIG. 1 (A) shows a state in which a flame-retardant coating material 40 is applied to the fireproof coating material 10 without allowing the penetrant to permeate and solidify. According to this, since the granular material 20 which consists of dust etc. adhering to the surface of the fireproof coating material 10 and the flame-retardant coating material 40 contact directly, it will be a point contact (adhesion is weak).
On the other hand, FIG. 1 (B) shows the present invention in which the penetrant 30 is infiltrated and solidified into the fireproof covering material 10. According to this, the penetrant 30 that cannot completely penetrate into the inside of the fireproof coating material 10 remains on the surface of the fireproof coating material 10 so as to cover the granular material 20 attached to the surface of the fireproof coating material 10. The flame-retardant coating material 40 is in surface contact with the penetrant 30 (high adhesion).

  Therefore, by providing the inorganic fiber scattering prevention treatment structure shown in FIG. 1 (B), the adhesion between the surface of the flame-retardant coating material and the fire-resistant coating material is improved in the hard and liquid-resistant fire-resistant coating material. (Primer effect), penetrant can act as an anchor for flame retardant coating material (anchor effect), and double protection of the surface of the fireproof coating material can surely prevent the scattering of inorganic fibers from the fireproof coating material Become.

  Examples of the present invention will be described below.

<Asbestos scattering prevention test>
The test result of the inorganic fiber scattering prevention treatment according to one embodiment of the present invention will be described. In addition, since “asbestos” is not available as an inorganic fiber at present, “asbestos” having properties similar to those of asbestos is used in this test. FIG. 2A is a configuration diagram of the test apparatus. The test apparatus includes a generally airtight storage box 2 that stores the test body 1, a particle counter 3 that measures the number of fine dust in the storage box 2, a nozzle 4 that blows air onto the test body 1, and a nozzle 4. And a compressor 5 for supplying air.

  In this example, two types of test bodies A and B were used as the test body 1 and subjected to different inorganic fiber scattering prevention treatments. Specimen A simulates asbestos on a steel plate of 150 mm × 300 mm × 3 mm, and wet sprayed rock wool is sprayed at a thickness of 50 mm using rock wool as a component and cured for a certain period of time to obtain a rock wool-containing material. FIG. 2B shows a cross section of the specimen A. On the other hand, the test body B is obtained by making seven straight cuts having a depth of 6 mm on the surface of the test body A. FIG. 2C shows a cross section of the specimen B. This assumes that the asbestos-containing material used in existing buildings has scratches, cracks, etc. on its surface.

The inorganic fiber scattering prevention treatment X is one in which a penetrant is infiltrated and solidified on the surface of a test body, and the surface is further coated with a flame retardant coating material.
・ Splash prevention treatment X
First, a penetrant containing 4% by weight of polyvinyl alcohol having a polymerization degree of 1700, a saponification degree of 87 mol%, a solution concentration of 4%, and a solution viscosity of 5.4 cP was set to a penetration depth of about 5 mm on the entire surface of the test specimen. -Solidify, and further, 20% by weight of modified acrylic resin as synthetic resin emulsion (40% by weight as modified acrylic emulsion), titanium dioxide as inorganic filler, aluminum hydroxide and calcium sulfate as flame retardant A flame retardant coating material containing 60% by weight was applied to the entire surface of the test body to form a coating film.

  Then, each of the test bodies A and B is subjected to anti-scattering treatment X, air is blown from the nozzle 4 to the test body surface at a wind speed of 12 to 15 m / s for 10 minutes, and the particle counter 3 counts the number of dust in the storage box 2. Was measured respectively. In addition, as a comparative example, the number of dusts in the storage box 2 was measured for each of the case where the test body was not stored in the storage box 2 and the case where the test piece A was not subjected to the scattering prevention process X. The test results are shown in FIG.

  When the anti-scattering treatment is performed, the number of dust is significantly smaller than when the anti-scattering treatment is not performed, and since the number of dust is almost the same as when the test specimen is not accommodated in the storage box 2, the liquid is hard and liquid. It was confirmed that the penetrant penetrated even in wet spray rock wool which is difficult to penetrate, and numerically it was confirmed that rock wool simulating asbestos was not scattered at all.

<Durability test>
Next, the durability test by the inorganic fiber scattering prevention treatment will be described. In this durability test, the above-mentioned test bodies A and B subjected to the above-described scattering prevention treatment X and the test body A not subjected to the above-described scattering prevention treatment X were targeted. Then, the process of placing in a humid environment with an air temperature of 60 ° C. and a humidity of 95% for 16 hours and then placing it in a dry environment of an air temperature of 60 ° C. and a humidity of 30% for 8 hours is repeated 10 cycles, and then the above The effect of scattering prevention was tested. The test results are shown in FIG.

  When the scattering prevention treatment X is performed, the number of dust is remarkably smaller than when the scattering prevention treatment is not performed, and the number of dusts is almost the same as when the specimen is not accommodated in the storage box 2. It was confirmed that the anti-scattering effect was not impaired at all.

  INDUSTRIAL APPLICABILITY The present invention is widely applicable as a technique for preventing scattering (containment) of inorganic fibers (for example, asbestos) of a fireproof coating material of a wet spray type or a molded plate type that is hard and difficult to permeate liquid.

10 Fireproof Coating Material 20 Granules 30 Penetration Agent 40 Flame Retardant Coating Material

Claims (3)

  By impregnating and solidifying the surface of a fire-resistant coating material, which is a wet-sprayed fire-resistant coating material or molded board fire-resistant coating material, containing inorganic fibers, and further coating the surface with a flame-retardant coating material In the inorganic fiber scattering prevention treatment method for preventing scattering of inorganic fibers from the fireproof coating material, a penetrant that cannot penetrate into the interior of the fireproof coating material remains on the surface of the fireproof coating material, An inorganic fiber scattering prevention treatment method characterized by covering a granular material adhering to a surface or unevenness formed on the surface so that the penetrant and the flame retardant coating material are in surface contact.   The inorganic fiber scattering according to claim 1, wherein polyvinyl alcohol having a polymerization degree of 500 to 2000, a saponification degree of 70 to 95 mol%, a solution concentration of 1 to 8%, and a solution viscosity of 5 to 500 cP is used as the penetrant. Prevention treatment method.   The inorganic fiber according to claim 1 or 2, wherein the flame retardant coating material contains a synthetic resin emulsion containing a solid content of 35 wt% to 80 wt%, a flame retardant, and an inorganic filler. Anti-scattering treatment method.

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