JPH01250558A - Dust-preventing and peeling-removing treatment of building material containing inorganic fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for preventing dusting of buildings containing inorganic fibers and a method for removing peeling of building materials containing inorganic fibers. A treatment method that prevents dusty asbestos from scattering from building materials by impregnating building materials with a modified polyvinyl alcohol aqueous solution, and removing asbestos-containing building materials from concrete walls or steel frames and refinishing the surface. Regarding removal treatment method.

(Prior Art) In existing concrete buildings, houses, etc., it has become a problem that asbestos and the like gradually scatter into the air from building materials such as side walls and ceilings containing inorganic fibers such as asbestos.

In particular, there are many existing heat-insulating and sound-absorbing building materials that contain asbestos, but recently the asbestos in these building materials has become a social issue due to its harmful effects when it turns into dust and enters the human body.

For this reason, existing asbestos-containing building materials can be sprayed with a vinyl acetate emulsion to hide the surface, or sprayed with a water-soluble polymerized metal material made of synthetic resin (acrylic acid, etc.) to infiltrate the asbestos. Attempts are being made to contain the dust.

(Problems to be Solved by the Invention) However, although the method using vinyl acetate emulsion (2) in the prior art has a great effect of concealing the surface of asbestos-containing building materials, it has little penetration into the interior. Spraying has the disadvantage of causing separation between the layers that have not penetrated, and also has the disadvantage that asbestos inside the building materials will scatter during P4, which involves dismantling and renovating building materials containing asbestos.

In the method (2) above using a synthetic resin-based water-soluble polymer such as acrylic acid, even if the concentration is adjusted, 4 to 5 IL does not permeate through the surface of the building material, so it is effective in preventing dusting of the building material. is insufficient, and the material cost is also high.

(Means for solving the problem) As a result of various studies to solve the above problem, the inventor of the present invention found that
First, we developed a method that could easily and inexpensively prevent building materials from turning into dust by impregnating asbestos-containing building materials with an aqueous polyvinyl alcohol (PVA) solution.
It was proposed as No. 95274.

The invention was developed as a result of various experiments conducted by the inventor on water-soluble binders, such as carboxymethyl cellulose (
If CM C), sodium alginate, or sodium polyacrylate is used, it will react with the cement in asbestos-containing building materials and cause coagulation and precipitation, making it difficult to exert the binder function.
The patent application was filed based on the finding that polyvinyl alcohol is superior to other conventionally known materials, whereas polyvinyl alcohol (PEG) does not cure.

In other words, polyvinyl alcohol can be applied directly as an aqueous solution, has excellent permeability to coating materials as a building material, and has excellent adhesive curing properties as an adhesive, so it is used as a dust prevention agent for coating construction materials. Polyvinyl alcohol aqueous solution was proposed as a dusting prevention agent because it is suitable.

One of the objects of the present invention is to improve the method for preventing dusting using polyvinyl alcohol, and the method for preventing dusting of building materials containing inorganic fibers, which is characterized by impregnating the building materials containing inorganic fibers with an aqueous solution of modified polyvinyl alcohol. and to provide a dusting prevention treatment agent.

Another object of the present invention is to impregnate an inorganic fiber-containing building material layer on the surface of a concrete structure with modified polyvinyl alcohol, then peel and remove the impregnated layer, and then finish the surface of the inorganic fiber-containing building material. It is to provide law.

That is, the present invention provides (1) a method for preventing dusting of inorganic fiber-containing building materials, which is characterized by impregnating the inorganic fiber-containing building materials with a modified polyvinyl alcohol aqueous solution, and (2) concrete having an inorganic fiber-containing building material layer on the surface layer. A first step of impregnating the surface layer of the structure or steel frame with modified polyvinyl alcohol, a second step of peeling off and removing the inorganic fiber-impregnated building material layer on the surface layer of the concrete structure or steel frame subjected to the first step, and the second step. A third step of cleaning and smoothing the exposed surface of the concrete structure or steel frame base by brushing, etc., and applying a copolymer-based resin of vinyl acetate and ethylene to the surface of the concrete structure or steel frame subjected to the third step. This is a peeling removal treatment method for inorganic fiber-containing building materials, which is characterized by comprising a fourth step of coating with a polyacrylic acid ester resin.

Inorganic fiber-containing building materials according to the present invention typically include asbestos fiber-containing building materials 1, for example, material layers for asbestos spraying on concrete walls, fireproof covering materials, etc., but materials containing artificial inorganic fibers such as rock wool also applies.

The modified polyvinyl alcohol used in the present invention includes inorganic acids such as sulfonic acid and its derivatives as a modifying agent, such as para-toluenesulfonic acid.

Further, organic acids such as carboxylic acids 1 such as succinic acid, adipic acid, maleic acid, fumaric acid, phthalic acid, etc. may be mentioned, and in particular, those using maleic acid, which is an unsaturated dicarboxylic acid, may be mentioned. can.

Furthermore, aldehydes such as butyraldehyde, formaldehyde, etc. may be used.

Note that derivatives thereof can also be used.

In the above, inorganic acid-modified polyvinyl alcohol is
For example, in the case of sulfonic acid-modified polyvinyl alcohol,
Polyvinyl alcohol in which about 20% is modified with sulfonic acid is good in terms of penetration depth into inorganic fiber-containing building materials and film-forming properties.

The modified polyvinyl alcohol used in the present invention has better permeability to building materials containing inorganic fibers such as asbestos than polyvinyl alcohol alone, and from the viewpoint of permeability and film-forming properties, those with a degree of polymerization of 500 or less are preferred. preferable.

However, if the thickness of the asbestos building material is 301111I or less, polyvinyl alcohol alone (polymerization degree of 4000 to 250
, saponification degree of 75 to 100%) can be added and mixed in a ratio of 0.1 to 9 (weight ratio) to 1 part of modified polyvinyl alcohol.

The concentration of modified polyvinyl alcohol in the aqueous impregnating solution for spraying is preferably 2 to 30 parts by weight per 100 parts by weight of water, and if it is less than 2 parts by weight, the asbestos containment effect is poor;
If it exceeds 0 parts by weight, the solubility is poor, particularly preferably 2 parts by weight.
It is around 0 parts by weight.

Other regulators are preferably added to the modified polyvinyl alcohol aqueous solution of the present invention.

Conditioners include glycerin, diammonium phosphate,
Sodium dehydroacetate, titanium oxide, calcium carbonate, tripolyphosphoric acid, penetration aids, fragrances, etc. are added.

Glycerin imparts flexibility to the polyvinyl alcohol film, and is preferably added in an amount of 2 to 20 parts by weight per 100 parts by weight of water.

When the amount of glycerin exceeds 20 parts, the strength as a binder for modified polyvinyl alcohol is impaired, and when it is less than 2 parts by weight, it becomes too hard and brittle, and the impact resistance is poor. Particularly preferably, it is around 4 parts by weight.

Diammonium phosphate acts as a flame retardant and has a 0.
It is preferable to add 1 to 2 parts by weight.

Although phosphoric acid esters may be used, diammonium phosphate is advantageous in terms of cost.

1. An anti-septic agent, such as sodium dehydroacetate, is 0°00
By adding 1 to 1 part by weight, spoilage of modified polyvinyl alcohol can be prevented. If it is less than 0.001 part by weight, no antiseptic effect will be produced, and if it exceeds 1 part by weight, permeability will be poor.

Titanium oxide and calcium carbonate serve to increase the surface hardness after coloring (white) and spraying.

In asbestos building materials with many voids (low density), titanium oxide alone may penetrate into the interior and may not be able to increase coloration or surface hardness.

Therefore, calcium carbonate with a coarser particle size (2 to 1
When used together with 5μl11), coloring becomes easier.

If it is less than 5 parts by weight, no coloring will occur, and if it exceeds 30 parts by weight, the permeability will be poor.

Therefore, it is preferable to add 5 to 30 parts by weight of both.
Particularly preferably, it is around 10 parts by weight.

Like glycerin, tripolyphosphoric acid has the effect of softening the film, and the amount added is preferably 1 to 5 parts by weight.

As a penetration aid, for example, "Doveguchi W77J (product name:
gj (manufactured by Sannopco) is useful for good adhesion between asbestos and the binder, and the amount added is 0.1 to 2.
Parts by weight are preferred.

Other flavoring agents include lemon essential oil, cypress essential oil, etc., and small amounts of these can be added.

The above three tables are as shown in Table 1.

Modified polyvinyl alcohol 2-3°glycerin 2-30 diammonium phosphate 0.1-2 tripolyphosphoric acid
1 to 5 dehydro[acid soda
0.001-1 acid f titanium
5-30 calcium carbonate
5-30 Lemon essential oil 0. Q
OO1~I Cypress essential oil 0.000
1~1 water
100 Here, comparative test results clearly showing the superiority of the modified polyvinyl alcohol aqueous solution according to the present invention will be explained below.

Using an asbestos board measuring 300 m x 3 Q Omm x 30 mm, various polyvinyl alcohol aqueous solutions (however,
The permeability and film-forming property of titanium oxide (containing 10% titanium oxide, binder concentration 10%), sodium polyacrylate aqueous solution (commercially available asbestos dust prevention treatment agent), water, etc. were measured.

The permeability was measured by immersing the end of the asbestos board in each sample penetrating solution and measuring the distance and time that the solution penetrated and rose.

Film-forming properties were evaluated by visual observation and finger touch.

The results are shown in FIG. 1, and the permeation rate of a 10% aqueous solution of polyvinyl alcohol is 0.5%, regardless of its degree of polymerization or saponification. It is about 1 cm/sin. Even in an aqueous solution with a polyvinyl alcohol concentration as low as 1%, the permeation rate is about 0.2 cm/sin.

On the other hand, the modified polyvinyl alcohol of sample No. 6 (“Ko-rin l-3266J” trade name: Nippon Gosei Kagaku Kogyo: G
) 10% aqueous solution has a penetration rate of approximately 0.35cm/m
In and polyvinyl alcohol alone, the amount is more than three times that of polyvinyl alcohol alone, and in addition to this, the penetration aid
7. The permeation rate of the aqueous solution No. 7 containing 1.5% of 7. (Product name: Tsumesun Nobuko Co., Ltd.) is 0.58 cm/l.
It can be seen that it is much faster than l1n. In addition, film-forming properties are determined by polyvinyl alcohol and modified polyvinyl alcohol.
- All of the samples were in good condition.

On the other hand, in the case of treatment agents No. 8 and No. 9 that use commercially available sodium polyacrylate, even though the penetration rate is somewhat good, there is no film-forming property and they become powder-like.
It does not form a film and is defective.

However, when the asbestos boards sufficiently impregnated with polyvinyl alcohol aqueous solution or modified polyvinyl alcohol according to samples No. 1 to No. 7 were dried and then crushed and dismantled with a hammer, no asbestos scattering occurred and the dusting was satisfactory. A preventive effect was observed.

Next, a detailed description will be given of the method of the present invention in which the inorganic fiber-containing building material layer laminated on the concrete ellipse is subjected to peeling and removal treatment.

Also in this method, in the first step, the inorganic fiber-containing building material layer is first impregnated with the same modified polyacrylic aqueous solution as in the dusting prevention treatment method. However, in this case, the concentration of the modified polyvinyl alcohol aqueous solution used is much lower than that in the dusting prevention treatment method,
This is made to satisfactorily impregnate all layers of the layer to be peeled and removed.

Next, in a second step, the impregnated layer is peeled off and removed using a scraping tool such as a scraper. In this peeling and removal work using a scraping tool, since the layer to be peeled and removed has already been impregnated with a modified polyvinyl alcohol aqueous solution in the first step,
Very little inorganic fiber dust is dispersed into the air.

In the third step, the surface of the concrete structure substrate injected in the second step is brushed (using a rotating wire brush, etc.) to completely remove the inorganic fiber-containing building material layer and smooth the surface of the substrate.

In the fourth step, a prepolymer of a copolymer resin of vinyl acetate and ethylene or a polyacrylate resin is applied to the smoothed surface and polymerized to form a coating layer. In this case, if necessary, a pigment such as titanium oxide may be mixed and used as a concealing agent.

This coating layer has an extremely high adhesive strength with concrete, and has the effect of protecting the surface of the concrete structure base and making it beautiful.

Furthermore, it is characterized by extremely high adhesion strength with other finishing materials.

That is, a finishing material such as a mixture of hillite, pearlite, etc. and mortar, or rock wool spraying material, etc. is applied on the surface of the coating layer subjected to the fourth step to make the surface of the concrete structure base beautiful. Finishing is also preferred, and the present coating layer has very good adhesion to this finishing material.

For example, adhesive strength several tens of times higher than that of conventional coating agents such as vinyl acetate can be obtained.

As described above, the purpose of implementing the method of the present invention is mainly to contain asbestos and other inorganic fiber dust in building materials, and to prevent asbestos and other inorganic fiber dust from forming during demolition and removal work of buildings. Application, dipping, spraying, etc. are carried out, but the internal penetration treatment can also be carried out satisfactorily by using a device equipped with a needle tube 2 as shown in FIG.

FIG. 2 shows an example in which a modified polyvinyl alcohol aqueous solution is infiltrated into an inorganic fiber-containing building material (asbestos board) 5. In this case, the modified polyvinyl alcohol By pumping the aqueous solution with a pump 4, the modified polyvinyl alcohol aqueous solution is injected from the pores 3 of the needle tube inserted into the inorganic fiber-containing building material 5.

Note that the needle tube is implanted so that its hole communicates with the inside of the pipe body.

In this case, each needle tube 2 has many pores 3 on its peripheral wall.
are provided, and asbestos spraying involves supplying the modified polyvinyl alcohol aqueous solution directly deep within the village through these pores, allowing the infiltration work to be carried out quickly and sufficiently.

(Example) Next, examples of the present invention will be described.

First, two types of dusting prevention treatment agents A and B having the following compositions were prepared.

[Dusting prevention treatment agent A] Modified polyvinyl alcohol (Ko-+?N L-326
6 (manufactured by Nippon Gosei Kagaku Kogyo)) 20 parts by weight Titanium oxide 10 parts by weight Penetration aid (manufactured by San Nobuco) 2 parts by weight Water (ion exchange water) 100 parts by weight Dust prevention treatment agent B] Modified polyvinyl alcohol (Co'-Oten L-3266
(Translated by Nippon Gosei Kagaku Kogyo)) 20 parts by weight Glycerin 4 parts by weight Sodium tripolyphosphate 1 part by weight Diammonium phosphate 1 part by weight Sodium dehydroacetate
0.011 heavy lemon essential oil
o, oos parts by weight Cypress essential oil 0.
08 parts by weight Penetration aid C9” 7” O door 7 (manufactured by Nnofuco) 2 parts by weight Water (ion exchange water)
Using 100 parts by weight of 2N of the above-mentioned dusting prevention treatment agents A and B separately, dusting prevention treatment and exfoliation removal treatment of inorganic kIi fiber-containing building materials were carried out.

The building material to be treated is a layer of asbestos-containing sprayed material laminated on a concrete wall (asbestos content: 60%, density: 0.3, area: 100 x 100 c+s, thickness: 6 am).

■ Example of containment of asbestos dust by infiltration: Using the infiltration apparatus shown in FIG. 2, a 2-fold dilution of the treatment agent was infiltrated into the layer of the building material to be treated.

The insertion depth of the nozzle is 5.5 cm, and the jet amount is 3°71/w.
Infiltration was carried out under conditions of in.

After that, the undiluted solution was used to finish the surface.

■ Example of surface treatment by spraying: The above dusting prevention treatment agent was sprayed onto the building material to be treated using an airless spray gun.

Blow M: 2.81/2 wheels The purpose of this is to greatly increase the surface hardness and improve the impact resistance against flying objects such as balls.

■ Example of dismantling and peeling removal treatment of asbestos-containing building materials by spraying: After spraying each of the 8-fold diluted solutions of the above-mentioned dust prevention treatment agents onto the above-mentioned building materials to be treated using an airless spray gun (manufactured by Iwata Painter). The asbestos was removed by scratching with a scraping tool.

Spraying amount: 61/[112 A rotating brush (using a wire brush) is applied to the surface of the concrete structure substrate that has been hammered out during the removal process, and the unremoved asbestos spray is completely removed and cleaned, and at the same time, the concrete structure is removed. The surface of the object was smoothed.

Next, a coating agent made by adding and mixing fine titanium oxide powder to polyacrylic butyl ester was applied to the smoothed surface, and polymerized and hardened to form a beautiful smooth concrete surface.

Furthermore, "Dancoat PJ" (manufactured by Ohashi Chemical Industry Co., Ltd., a lightweight finishing aggregate paint containing vermiculite) was further applied on the coating layer to obtain a soft surface finish.

As a result of the above, ■In the case of All the asbestos was tied together.

The degree of asbestos scattering is 0.02f//, the same as outside! It was about.

In the case of ■, the surface hardness of the asbestos-containing building material layer was so high that no damage occurred even when a ball was thrown at it.

In case (2), the diluted solution of the dusting prevention treatment agent A or B penetrated deep into all the asbestos building material layers, and was able to sufficiently prevent the scattering of dust during the i+rm removal of asbestos.

In addition, the coating layer has a beautiful smooth surface with excellent appearance, and has high adhesive strength with concrete (adhesive strength = 5 to 4
It was also excellent in terms of 0 kg/c end 2), water resistance, alkali resistance, and various mechanical properties.

Furthermore, those coated with the finishing material had a high adhesion strength (5 to 10 kg/e transport 2), had a soft appearance, and were able to form a brand new and elegant wall surface.

(Effects of the Invention) As described above, according to the present invention, building materials containing asbestos and the like can be effectively prevented from turning into dust by impregnating building materials containing inorganic fibers with a modified polyvinyl alcohol aqueous solution.

The modified polyvinyl alcohol used in the method of the present invention has good permeability and film-forming properties, and the permeate acts as an adhesive and fixes inorganic fibers such as asbestos well, so the permeation treatment work is easy. The effect of preventing dust formation is also sufficiently achieved.

Furthermore, it is possible to prevent harmful dust from scattering even during demolition work of permeated building materials.

Furthermore, if a coating layer is formed on the concrete surface from which inorganic fiber-containing building materials have been peeled off, the adhesive strength between it and the concrete is extremely high, so the coating layer will not peel off, and the surface will remain beautiful and durable. A concrete wall surface with good quality can be obtained.

Furthermore, if a finishing material is further applied to the surface of the coating layer, a more elegant and brand-new wall surface can be formed.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the permeability and film-forming properties of a dusting prevention treatment agent for various inorganic fiber-containing building materials, and Figure 2 is a schematic diagram of an example in which a modified polyvinyl alcohol aqueous solution is permeated into the building material using an infiltration device. It is. 1: pipe body, 2: needle pipe, 3: pore, 4: pump, 5: asbestos board,

Claims (12)

[Claims] (1) A method for preventing dusting of inorganic fiber-containing building materials, which comprises impregnating the inorganic fiber-containing building materials with a modified polyvinyl alcohol aqueous solution. (2) The method for preventing dusting of inorganic fiber-containing building materials according to claim 1, wherein the modified polyvinyl alcohol is modified with sulfonic acid or a derivative thereof. (3) The method for preventing dusting of inorganic fiber-containing building materials according to claim 1, wherein the modified polyvinyl alcohol is modified with maleic acid or a derivative thereof. (4) The method for preventing dusting of building materials containing inorganic fibers according to claim 1, wherein the modified polyvinyl alcohol is modified with an aldehyde or a derivative thereof. (5) The method for preventing dusting of inorganic fiber-containing building materials according to any one of claims 1 to 4, wherein the modified polyvinyl alcohol has a degree of polymerization of 500 or less. (6) The inorganic fiber-containing inorganic fiber-containing solution according to any one of claims 1 to 5, wherein the modified polyvinyl alcohol aqueous solution contains 2 to 30 parts by weight of modified polyvinyl alcohol per 100 parts by weight of water. A treatment method to prevent building materials from turning into dust. (7) The modified polyvinyl alcohol aqueous solution contains 2 to 20 parts by weight of glycerin and 0.1 to 2 parts by weight per 100 parts by weight of water.
parts by weight of diammonium phosphate, 0.1 to 4 parts by weight of tripolyphosphoric acid, 0.001 to 1 part by weight of sodium dehydroacetate, 5 to 30 parts by weight of titanium oxide, and 5 to 30 parts by weight of calcium carbonate. 7. The method for preventing dusting of building materials containing inorganic fibers according to claim 6. (8) A first step of impregnating the surface layer of a concrete structure or steel frame with a building material layer containing inorganic fibers with modified polyvinyl alcohol; and a building material layer impregnated with inorganic fibers on the surface layer of the concrete structure or steel frame that has undergone the first step. A second step of peeling and removing the surface of the concrete structure or steel frame exposed in the second step, a third step of cleaning and smoothing the surface of the concrete structure or steel frame exposed in the second step by brushing, etc. A method for removing peeling of building materials containing inorganic fibers, comprising: a fourth step of coating the surface with a copolymer resin of vinyl acetate and ethylene; (9) The method for removing peeling of inorganic fiber-containing building materials according to claim 8, wherein the coating in the fourth step is performed using a polyacrylic acid ester resin. (10) The method for removing peeling of inorganic fiber-containing building materials according to claim 8 or 9, wherein the coating agent is a mixture of titanium oxide. (11) The method for peeling and removing inorganic fiber-containing building materials according to claim 8 or 9, characterized in that a finishing material is applied to the surface on which the coating film is formed by the coating agent. (12) A dusting prevention treatment agent for inorganic fiber-containing building materials, which is made of modified polyvinyl alcohol obtained by modifying polyvinyl alcohol with sulfonic acid, maleic acid, aldehyde, or a derivative thereof.