JP5273912B2 - Dust scattering prevention treatment agent and treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dust-fly preventing treatment agent which prevents a sprayed asbestos from the dust-fly without impairing the original performances such as the fire resistance of the sprayed asbestos layer. <P>SOLUTION: The first dust-fly preventing treatment is a kit comprising a penetrating and solidifying agent having the principal component of an alkali silicate aqueous solution and a hardener having the essential components of magnesium sulfate and an amino acid. The second dust-fly preventing treatment agent is a kit comprising a penetrating and solidifying agent having the principal component of an alkali silicate aqueous solution, and a hardener having the essential components of magnesium sulfate and an amino acid, and also a surface solidifying agent which has the essential component of at least one kind of an inorganic hardening component selected from the group consisting of an alkali silicate aqueous solution, calcium sulfite, calcium thiosulfate, active magnesium oxide and magnesium sulfate and which contains an inorganic paint component. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention is a processing agent and a processing method for preventing dust scattering from a spraying layer such as asbestos in an existing building or the like, and more specifically, a dust scattering prevention processing agent kit for a spraying layer, The present invention relates to a containment method, a dust scattering inhibitor, a residual fiber solidifying agent, a spray layer removing method, and a residual fiber solidifying method.

  Throughout the claims and the entire specification, the term "spraying layer that may cause dust scattering" refers to dust that is harmful to the human body from the surface of the layer, such as a spraying asbestos layer or a spraying rock wool layer. Let's say the spraying layer and the building material surface layer that have fear.

  Asbestos has been widely used for building materials since it has excellent fire resistance and fire resistance as well as high sound absorption and heat insulation performance. However, since the fine dust is known to cause health problems such as lung cancer and mesothelioma, its use is restricted, and various methods for preventing the scattering of sprayed asbestos dust in existing buildings have been studied. ing. In other words, the use of sprayed asbestos, which is likely to generate dust, is currently completely banned due to the revision of the rules for the prevention of specific chemical substances, etc. in 1975, but walls, ceilings, etc. in buildings until the early 1975 Machine rooms storing air conditioning equipment, etc. that need soundproofing, the back of stairs, parking lot ceilings, factories, etc. or pipes that need heat insulation, etc. that have been widely constructed for the purposes of fire resistance, heat insulation, sound absorption, etc. It remains and is said to have exceeded 100,000 tons. Moreover, the sprayed asbestos layer of these existing buildings deteriorates due to secular change, breakage, wear, etc., so that fuzz, fiber collapse, sagging, floating between the ground and the asbestos layer, peeling, local damage or loss of the layer As an appropriate treatment method according to the situation, the removal method, the solidification method containment method such as applying and infiltrating special chemicals, etc. It is to be selected and constructed from three methods of enclosing method that covers with a sheet or a decorative board.

Conventionally, various materials and construction methods have been applied for the solidification method. For example, an asbestos solidification method in which an alkali silicate aqueous solution is applied and penetrated into a sprayed asbestos layer and then a curing agent containing a polyvalent metal compound and / or an amino acid is applied and solidified is proposed (see Patent Document 1). Asbestos-containing material is internally infiltrated with a composition comprising a vinyl-acrylic acid ester copolymer, an acrylic resin or a modified acrylic resin, an inorganic filler and water as main components, and then a synthetic resin and an inorganic flame retardant. An asbestos scattering prevention treatment method has been proposed in which an asbestos-containing material is solidified with an asbestos scattering prevention treatment mainly composed of an inorganic filler and water (see Patent Document 2).
Japanese Patent Laid-Open No. 3-5385 JP-A-6-49391

  However, since the evaluation criteria for the required performance after solidification are not yet constant, various characteristics of the solidified sprayed asbestos layer, that is, suppression of dust scattering, durability or fire resistance derived from asbestos, heat insulation The characteristics such as sound absorption vary from manufacturer to manufacturer, and an effective solidification method has not yet been developed.

  In view of such a situation, the present inventors have intensively studied for the purpose of preventing dust scattering of sprayed asbestos and the like without impairing the original performance such as fire resistance of the sprayed asbestos layer. As a result, the inventors have found that the object can be sufficiently achieved by using the dust scattering prevention treatment agent kit described below or the kit and a surface solidifying agent in combination, and have completed the present invention.

The invention according to claim 1
It is a dust scattering inhibitor composed of an aqueous alkali silicate solution.

The invention according to claim 2
After spraying and spraying a dust dispersion inhibitor made of an aqueous alkali silicate solution onto a spray layer that may cause dust scattering, the entire spray layer that may cause dust scattering is removed from the ground. This is a method for removing a spray layer that may cause dust scattering.

The invention according to claim 3
After applying and infiltrating a dust scattering inhibitor made of an aqueous alkali silicate solution to the spray layer that may cause dust scattering, the entire spraying layer that may cause dust scattering is removed from the ground and the dust suppressing agent is added to the spray layer. This is a method for removing a sprayed layer having a possibility of dust scattering, characterized in that it is dispersed in the air at a removal work site to capture scattered matter.

Examples of the alkali silicate contained in the osmotic solidifying agent (A) include aqueous solutions of sodium salt, potassium salt, lithium salt or quaternary ammonium salt of silicic acid, and a molar ratio SiO ₂ / M ₂ O (M is Na , K, Li, represent NH ₄₎ is preferably from 1.0 to 5.0. The alkali silicate concentration in the aqueous solution can be selected according to the thickness, density, desired strength, etc. of the “spraying layer that may cause dust scattering” to be treated. From the point, it is 2 to 30% by weight, preferably 6 to 24% by weight in terms of solid content of alkali silicate. If this concentration is less than 2% by weight, the strength may be insufficient, and if it exceeds 30% by weight, internal penetration may not be sufficient.

  The osmotic solidifying agent is solidified by coating and penetrating the curing agent after coating, but is cured by drying, and is cured by reacting with the cement component of the sprayed asbestos layer and carbon dioxide in the air.

  Additives such as a colorant, a thickener, a water repellent, a retarder, a dispersant, or a leveling agent can be added to the osmotic solidifying agent in the range of 0 to 20% by weight.

  Examples of amino acids contained in the curing agent (B) include monoamino monocarboxylic acids such as glycine, alanine, valine, leucine, phenylalanine, threonine, serine, proline, tryptophan, methionine, cysteine, cystine, and aminobenzoic acid. 1 type or 2 selected from acidic amino acids consisting of monoaminodicarboxylic acids such as aspartic acid, glutamic acid, asparagine and glutamine; basic amino acids consisting of diaminomonocarboxylic acids such as lysine, hydroxylysine, arginine and histidine A mixture of seeds or more can be mentioned. As a preferred amino acid, for example, a neutral amino acid such as glycine is used.

As for the amount of amino acid, the amount of curing agent that can maintain the original fire resistance of asbestos that passes the non-combustible material from the data of the maximum heat release rate and the total heat value of the non-flammability test (cone calorimeter test), that is, the amount of amino acid applied Is preferably 450 g / m ² or less, more preferably 300 g / m ² or less in terms of solid content.

  Additives such as colorants, thickeners, water repellents, retarders, dispersants or leveling agents can be added to the curing agent in the range of 0 to 20% by weight.

  In addition to these, the curing agent may contain up to about 1% by weight of alkali fluorosilicate.

  The curing agent contains these components in the form of an aqueous solution of 1 to 40% by weight, preferably 5 to 15% by weight in terms of solid content. If this concentration is less than 1% by weight, the strength may be insufficient, and if it exceeds 40% by weight, it may be difficult to apply and penetrate uniformly.

  The alkali silicate contained in the surface solidifying agent (C) may be the same as or different from the alkali silicate contained in the osmotic solidifying agent (A). As the aqueous alkali silicate solution, an aqueous solution of sodium silicate, potassium silicate or lithium silicate, which is generally known as water glass, is preferably used.

  The surface solidifying agent further contains at least one inorganic hardening component selected from the group consisting of calcium sulfite, calcium thiosulfate and active magnesium oxide as an essential component, among which active magnesium oxide is preferable. Activated magnesium oxide is activated with an iodine adsorption of 30 to 300 mg I / g MgO.

  The surface solidifying agent contains these components in the form of a mixture of 1 to 75% by weight, preferably 40 to 65% by weight in terms of solid content. If this concentration is less than 1% by weight, the strength may be insufficient, and if it exceeds 75% by weight, it may be difficult to apply uniformly.

The surface solidifying agent (C) contains an inorganic coating component, which is an inorganic filler, an additive, and the like in addition to the above-mentioned alkali silicate aqueous solution and inorganic curing component. Typical examples of inorganic paints are selected from alkaline silicate aqueous solutions and inorganic hardeners such as calcium sulfite, calcium thiosulfate, activated magnesium oxide, calcium silicate, zinc oxide, aluminum hydroxide, alumina, hydrated alumina, etc. 1 type or 2 or more types and calcium carbonate, silica sand, barium sulfate, clay, kaolin, talc, bentonite, diatomaceous earth, perlite, shirasu balloon, hiruishi powder, glass beads, titanium oxide, inorganic fibers ( 1 type or 2 types or more selected from alkali-resistant glass fibers) and the like, and a colorant, pigment, thickener, water repellent, curing retarder, dispersant or leveling agent as an additive in the entire surface solidifying agent It is an inorganic paint added and mixed within a range of ˜80 wt%.

  Next, a method for containing the “spraying layer that may cause dust scattering” will be described.

First, in the osmotic solidifying agent application step, the solidifying agent is usually applied by airless coating. The coating amount varies depending on the thickness and density of the “spraying layer that may cause dust scattering” to be processed, the degree of adhesion to the substrate, the concentration of the solidifying agent, etc., but in terms of solid content per 10 mm thickness of the same layer And preferably 0.1 to 1.0 kg / m ² . If the coating amount is less than 0.1 kg / m ² , the penetration amount of the osmotic solidifying agent may be insufficient, and if it exceeds 1.0 kg / m ² , it may be difficult to uniformly apply and penetrate.

In the step of curing the coating penetrant, the curing agent is usually applied by airless coating after about 30 minutes after the coating of the penetrating solidifying agent. The coating amount of the curing agent is preferably 0.1 to 0.8 kg / m ² , more preferably 0.2 to 0.4 kg / m ² in terms of solid content. If the coating amount is less than 0.1 kg / m ² , the strength may be insufficient, and if it exceeds 0.8 kg / m ² , it may be difficult to uniformly apply and penetrate.

  When the curing agent comes into contact with the osmotic solidifying agent, gelation occurs instantaneously and silica gel is formed. In a closed space such as a room, the dust scattering effect is great. Although the curing agent is weakly acidic, “black skin” is generated on the steel member such as the steel frame and the iron plate as a base, and no red rust is generated, and an antirust effect is obtained.

  In the surface solidification step, the surface solidifying agent is applied after mixing the liquid agent (alkali silicate aqueous solution) and the powder (other powder components), and the obtained surface solidifying agent is passed about 30 minutes after applying the curing agent. Usually, it is applied using a spray. The surface solidifying agent is prepared by adding one or more selected from calcium sulfite, calcium thiosulfate and active magnesium oxide as an inorganic hardening component to an alkali silicate aqueous solution in a total amount of 30 to 300% by weight in terms of solid content. For example, an inorganic paint described in JP-B-59-38397 or JP-B-61-17864 is preferably used.

  The inorganic curing component may contain 0 to 300 parts by weight of calcium silicate with respect to 100 parts by weight, and further 0 to 300 parts by weight of zinc oxide. If necessary, magnesium silicate or aluminum hydroxide, alumina, You may add 0-150 weight part of hydrated alumina etc. In addition to these, barium sulfate, calcium carbonate, silica sand, pearlite, and the like can be added to the inorganic curing component in the range of 0 to 80% by weight in the surface solidifying agent.

  Additives such as colorants, thickeners, water repellents, cure retarders, dispersants or leveling agents can be added to the inorganic curing component in the range of 0 to 20% by weight.

The coating amount of the surface solidifying agent is preferably 0.8 to 1.5 kg / m ² in terms of solid content. If the coating amount is less than 0.8 kg / m ² , uniform coating may be difficult, and if it exceeds 1.5 kg / m ² , the layer thickness may be too thick. This layer thickness is preferably 0.5 to 1 mm. If this layer thickness is less than 0.5 mm, it may be difficult to apply uniformly. If it exceeds 1 mm, there may be a loss of working time, materials and labor, and it may cause cracks.

  The finished surface has no exposure of the spray layer that may cause dust scattering, has a great effect of preventing dust scattering even outdoors, and maintains various physical properties of the spray layer.

  More specifically, the spray layer containment method according to the present invention is as follows, for example, in the case of a sprayed asbestos layer, using an osmotic solidifying agent (A), a curing agent (B) and a surface solidifying agent (C). Is done.

  The sprayed asbestos layer, which has been selected to be contained as an appropriate treatment method through a thorough preliminary survey, is subjected to necessary partial repairs to remove coarse dust, oil, soot, etc. adhering to the surface. Next, a predetermined amount of the osmotic solidifying agent (A) is applied here using an airless coating machine or the like, and allowed to stand for 30 minutes or more to allow sufficient internal penetration. If necessary, press the surface with a trowel or roller.

  Next, after sufficiently stirring and mixing the curing agent (B), it is applied using an airless coating machine or the like. Since the hardening reaction of the osmotic solidifying agent (A) proceeds very rapidly in a wide temperature range from the cold temperature to the normal temperature, it is possible to immediately move to the next operation. However, since the cured film of the surface solidifying agent of the present invention has air permeability, there is no need to wait for the completion of the reaction.

  Next, a predetermined amount of the surface solidifying agent (C) is uniformly applied to the application surface using means such as spraying, brushing or roller coating, and if necessary, the surface is pressed with a trowel or roller. The surface solidifying agent (C) is rapidly cured at room temperature, but can be used for about 5 hours after preparation. It is desirable to leave the curing for more than one day.

  Next, a method for removing the “spraying layer that may cause dust scattering” and a method for solidifying the remaining fibers will be described using a spraying asbestos layer as an example.

  In the removal process to remove the sprayed asbestos layer from the ground, when removing the sprayed asbestos layer, a spraying agent that suppresses and prevents dust scattering is applied to the sprayed asbestos layer, and the sprayed asbestos layer to be removed is moistened before removal. Do work.

  In asbestos removal work, it is difficult to completely remove asbestos fibers, and the fibers remain on the ground surface. In order to solidify and contain the remaining asbestos fibers on the removal surface, a residual fiber solidifying agent is applied to the removal surface.

  The effects of the method of the present invention are as follows.

(1) The scattering of sprayed asbestos dust is almost prevented.

(2) The fire resistance, sound absorption and heat insulation, which are the original functions of the sprayed asbestos layer, are almost retained.

(3) The solidified product according to the method of the present invention exhibits excellent performance in hardness, adhesion strength and impact resistance.

(4) The treatment agent of the present invention is excellent in adhesion, and sufficiently adheres to underlying concrete, mortar, metals such as steel frames and steel plates, plywood and the like.

(5) The treatment agent of the present invention has a breathability, a breathability, a water retention property and a humidity control property, and exhibits an excellent antifungal property.

(6) The treatment agents of the present invention are both aqueous and odorless without the use of unnecessary organic solvents. (7) Since the curing agent according to the present invention contains magnesium sulfate and an amino acid, “black skin” is generated in an iron member such as a base steel frame, red rust is not generated, and an antirust effect is obtained.

(8) Since the main component of the osmotic solidifying agent and the surface solidifying agent according to the present invention are alkaline, red rust is unlikely to occur.

  As described above, the treatment agent and the treatment method of the present invention exhibit extremely excellent performance in environmental conservation and are industrially useful.

  Next, in order to specifically explain the present invention, some examples of the present invention and comparative examples for showing comparison with the examples will be given.

  Originally, the standard test piece for sprayed asbestos dust scattering prevention treatment agent is ideally made with sprayed asbestos, but asbestos substitutes sprayed rock wool layer test piece and ceramic blanket test piece due to current asbestos regulation problem It was used as a test piece.

  Sprayed rock wool is applied to a thickness of 40 mm with a plywood for concrete formwork as the bottom plate, is naturally cured for 7 days at room temperature, and then the mass change is less than 1% by weight in a dryer at 60 ° C. ± 3 ° C. A rock wool layer test piece dried and cured to a normal temperature was used as a standard test piece.

[Examples 1 to 3]
In Examples 1 to 3, a mixture obtained by sufficiently stirring and mixing 100 parts by weight of potash water glass (solid content 30% by weight) and 150 parts by weight of water as an osmotic solidifying agent was applied to a 40 mm thick sprayed rock wool base. It was sprayed and applied uniformly at a rate of 720 g / m ^{2 in} terms of solid content with an airless coating machine, and allowed to penetrate inside for 30 minutes. Thereafter, a mixture obtained by sufficiently stirring and mixing 100 parts by weight of magnesium sulfate, 50 parts by weight of glycine and 450 parts by weight of water as a curing agent is sprayed uniformly at a rate of 480 g / m ^{2 in} terms of solid content with an airless coating machine. It was applied and allowed to penetrate inside. Subsequently, as the surface solidification treatment, 100 parts by weight of potassium water glass (solid content 30% by weight), 30 parts by weight of water and 15 parts by weight of powdered active magnesium oxide having an iodine adsorption of 150 g / MgO, 45 parts by weight of barium sulfate, glass fiber 30 parts by weight, 15 parts by weight of talc, and 30 parts by weight of calcium carbonate were thoroughly sprayed and applied by spraying uniformly at a rate of 2000 g / m ² (twice the standard amount) in terms of solid content. Curing was allowed to stand at room temperature for 24 hours.

[Comparative Examples 1 and 2]
In Comparative Examples 1 and 2, the organic osmotic solidifying agent is a commercially available osmotic solidifying agent manufactured by Company A (solid content 15% by weight) and a polyvinyl alcohol osmotic solidifying agent manufactured by Company B (solid content 12% by weight). Was applied according to the specifications of each manufacturer, and 5 mm or more infiltrated into a 40 mm thick spray rock wool base and solidified to give a test piece (indicating solidification of 5 mm or more as an osmotic solidifying agent, and penetrating and solidifying less than 5 mm. Is labeled as a surface solidifying agent).

Evaluation test The nonflammability of the test pieces before and after the containment treatment in Examples 1 to 3 and Comparative Examples 1 and 2 was tested by the following method.

Nonflammability test (Cone calorimeter test) (ISO5660)
Using a cone heater, the standard test piece of the containment-treated test piece is heated and burned, a part of the combustion gas is taken into a gas analyzer, and the heat generation rate and total heat generation amount due to combustion of the sample are measured from the measured oxygen concentration. It was measured with a cone calorimeter using the oxygen consumption method (the principle that the calorific value of combustion is almost proportional to the amount of oxygen consumed by combustion, regardless of the material and composition).

The test results are shown in Table 1.

  When the construction site of the asbestos layer to be solidified is related to the interior restriction, it is particularly necessary to use a solidifying agent having the required fire prevention performance, but by solidifying with the penetration solidifying agent and surface solidifying agent of the present invention. From the results of the nonflammability test, it can be evaluated that it is equivalent to a nonflammable material (Examples 2 and 3).

[Comparative Examples 3, 4, Examples 4, 5]
In Comparative Examples 3 and 4 and Examples 4 and 5, a mixture obtained by sufficiently stirring and mixing 100 parts by weight of potassium water glass (solid content 30% by weight) and 150 parts by weight of water as an osmotic solidifying agent was 40 mm thick. The sprayed rock wool substrate was sprayed with an airless coating machine, and was uniformly sprayed onto the rock wool substrate surface at a rate of 720 g / m ^{2 in} terms of solid content and allowed to infiltrate for 30 minutes. Thereafter, a mixture obtained by thoroughly stirring and mixing 100 parts by weight of magnesium sulfate, 50 parts by weight of glycine and 1850 parts by weight of water as a curing agent is uniformly blown at a rate of 480 g / m ^{2 in} terms of solid content with an airless coating machine. It was applied and allowed to penetrate inside.

  The test specimen thus sealed was dried at 60 ° C. ± 3 ° C., and further cured for 7 days to be a standard test specimen. In addition, the test pieces subjected to repeated wet and dry treatment were dried at 60 ° C. ± 3 ° C., relative humidity 95 ± 5%, 16 hours, then 60 ° C. ± 3 ° C., and subjected to 10 cycles of dry and wet repeated treatment with 8 hours as one cycle. .

Evaluation Test The test pieces before and after the containment treatment in Comparative Examples 3 and 4 and Examples 4 and 5 were subjected to an air erosion test, an impact test, and an adhesion strength test by the following methods.

Air erosion test (conforms to “Standard test method for anti-scattering treatment agent” (examination certificate / special committee on asbestos dust scattering prevention))
Evaluate the degree to which sprayed rock wool fibers are scattered by applying air to the surface of the specimen under certain conditions for the untreated product and the standard specimen of the containment-treated specimen as it is and after the wet and dry repeated treatment. did.

Impact test (Conforms to “Standard test method for anti-scattering treatment agent” (examination certification / Asbestos dust anti-scattering expert committee))
Standard steel specimens of untreated and encapsulated specimens as they are and after a dry and wet repeated treatment, a steel ball weighing 536g was dropped naturally from the height of 100cm to the center of each specimen surface and the sprayed rock wool layer was damaged. -The dropout was evaluated and the depth (mm) of the indentation that occurred was measured. It is judged that the cohesive strength of the spray material will not be damaged if the indentation depth is around 10 mm or less (less than 10 mm) (“Study on quality standards of asbestos scattering prevention treatment agent” (March 1990, Construction Ministry of Building Research Institute, Japan Architectural Finishing Materials Association).

Adhesion strength test (according to “Standard test method of anti-scattering treatment agent” (examination certification / asbestos dust dust prevention expert committee))
A steel attachment with a size of 100 mm square is bonded with an epoxy adhesive to the surface of each untreated product and the standard specimen of the containment-treated specimen as it is and after repeated wet and dry treatment, in the vertical direction of the specimen surface. The sample was pulled at a speed of 1 mm / min, and the maximum tensile load (N / cm ² ) was measured.

The test results are shown in Table 2.

  Asbestos concentration is regulated by the Air Pollution Control Law and the Working Environment Measurement Law. In the above test results, the physical properties of the blank / untreated product are good, because the rock wool test piece is new and not yet deteriorated.

  Even when treated only with the osmotic solidifying agent of the present invention, it can be seen from the results of adhesion strength, impact resistance and air erosion test that the solidification purpose of the sprayed asbestos dust scattering prevention treatment is sufficiently achieved (Example 4). And 5). Furthermore, by using a surface solidifying agent in combination with this, dust scattering can be almost completely prevented.

[Reference Examples 1 to 4]
In Reference Examples 1 to 4, an osmotic solidifying agent (a) obtained by sufficiently stirring and mixing 100 parts by weight of potassium water glass (solid content 30% by weight) and 150 parts by weight of water, 100% by weight of calcium chloride (solid content 35% by weight) Part, glycine 30 parts by weight and water 160 parts by weight hardener (b), magnesium sulfate 100 parts by weight, glycine 50 parts by weight and water 450 parts by weight hardener (c) ) And liquid potash water glass (solid content 30% by weight) 100 parts by weight and 30 parts by weight of water were sufficiently stirred and mixed, and each of the liquid component (d) of the surface solidifying agent was tested for rust prevention.

  The test method for rust prevention is to degrease the surface of a cold rolled steel sheet (0.3 × 70 × 150 mm) of JIS G3141, immersed in the treatment solution for 48 hours, and visually observe the surface condition of the steel sheet and perform X-ray rotation. Analyzed.

The test results are shown in Table 3.

  Red rust was produced in the curing agent (b) containing calcium chloride and glycine, but black skin was produced in the curing agent (c) containing magnesium sulfate and glycine.

[Example 6]
In this example, following the operation of Example 5, as a surface solidifying agent, 100 parts of potassium water glass (solid content is 30%), 30 parts of water, 15 parts of active magnesium oxide, 45 parts of barium sulfate, 30 parts of glass fiber. Then, a mixture obtained by sufficiently stirring and mixing 15 parts of talc and 30 parts of calcium carbonate was sprayed uniformly at a rate of 1.8 kg / m ^{2 in} terms of solid content by spraying, and allowed to stand at room temperature for 24 hours.

  The test specimen thus sealed was dried at 60 ° C. ± 3 ° C., and further cured for 7 days to be a standard test specimen.

  This standard test piece has no exposure of the spray layer that may cause dust scattering, and has a large dust scattering prevention treatment effect.

[Example 7 (removal work / scattering inhibitor)]
When peeling and removing the sprayed asbestos layer, a scattering inhibitor was used in order to suppress and prevent asbestos dust from scattering. A mixture of 100 parts of potash water glass (solid content 30%), which is the main component of the osmotic solidifying agent, and 150 parts of water was sufficiently stirred and mixed to a 5-fold solution with water and used as a scattering inhibitor. Application | coating operation | work was performed with the airless coating machine, the scattering inhibitor was apply | coated uniformly in the ratio of 24g / m < ² > in solid content conversion per 10mm thickness of the spraying asbestos of a ceiling surface, and it was made to osmose | permeate the spraying asbestos layer. After the sprayed asbestos layer was sufficiently moistened, the asbestos removal work was carried out with cleansing using a manual skin peel. Asbestos remaining on the ground, such as the unland areas, was removed as much as possible using a wire brush.

  In the environment during the stripping and removing operation, the scattering of asbestos dust was suppressed and prevented. In addition, the asbestos that had fallen remained wet.

  “Asbestos dust concentration measurement” during the removal operation was performed by a counting analysis method using a phase contrast microscope. The result is “measurement evaluation B” (the harmful asbestos is hardly floating, but there is a possibility that the asbestos building material or the like is likely to float, or the environment is susceptible to other factors. / L or less, reference value: 10 f / L on site boundary standard for air pollution prevention law), scattering of sprayed asbestos dust was suppressed and prevented.

  The asbestos that had been peeled off and removed was collected with a bag and packed into a bag, which was hermetically packed. Although 3 hours have passed since the scattering inhibitor was applied, the generation of dust during work was also suppressed and prevented.

  The sprayed asbestos layer on the ceiling surface to which the scattering inhibitor has been applied 18 hours after the scattering inhibitor has been applied has a wet color and remains in a wet state. The scattering of was suppressed.

[Example 8 (removal work / residual asbestos fiber solidifying agent)]
The remaining asbestos fiber solidifying agent was applied to prevent the asbestos dust remaining on the groundwork after the removal work from being scattered. A mixture of 100 parts of potash water glass (solid content 30%), which is the main component of the osmotic solidifying agent, and 150 parts of water was used as the residual asbestos fiber solidifying agent. The coating operation is performed with an airless coating machine, and the residual asbestos fiber solidifying agent is uniformly applied to the residual asbestos surface of the ceiling surface at a rate of 24 g / m ^{2 in} terms of solid content and air-dried to contain the residual asbestos. Immobilized.

[Examples 9 to 11]
A ratio of 112.5 g / m ^{2 in} terms of solid content obtained by thoroughly stirring and mixing 100 parts of magnesium sulfate, 50 parts of glycine and 1850 parts of water as a hardening agent for the osmotic solidifying agent as a osmotic solidifying treatment on a 15 mm thick ceramic blanket substrate To infiltrate the inside uniformly.

100 parts of glycine and 400 parts of water as a curing agent for penetration solidification agent: uniformly interpenetrating what was sufficiently stirred and mixed (20% aqueous solution substantially saturated solution) in terms of the solid content at a rate of 300 g / ^{m 2} and 600 g / ^{m 2} I let you.

Evaluation test Examples 9-11 tested the nonflammability by the method mentioned above about the test piece before and after a containment process, the nonflammability test (cone calorimeter test) (ISO5660).

The test results are shown in Table 4.

Claims (3)

Apply and infiltrate the dust scattering inhibitor into the sprayed asbestos layer, moisten, and then apply the sprayed asbestos layer to remove the sprayed asbestos layer wet with the dust scattering inhibitor without any other treatment. a dusting inhibitor used to wet impregnated, consists of aqueous alkali silicate solution, powder dust scattering inhibitor. After spraying and infiltrating a dust dispersion inhibitor made of an aqueous alkali silicate solution into a spray layer that may cause dust scattering, the spray layer in which the dust scattering inhibitor is moistened without any other treatment A method for removing a spray layer having a risk of dust scattering, wherein the whole is removed from the ground. Apply and infiltrate a dust dispersion inhibitor made of an aqueous alkali silicate solution into a spray layer that may cause dust dispersion, and then apply the entire spray layer where the dust dispersion inhibitor is moist without any other treatment. A method for removing a sprayed layer having a possibility of dust scattering, wherein the spraying agent is removed from the ground and the scattering inhibitor is dispersed in the air at the removal work site to capture the scattered matter.