JPH0221984A - Treating agent for stripping asbestos layer - Google Patents

Abstract

PURPOSE:To obtain a hardly evaporable treating agent for stripping an asbestos layer having superior sticking and penetrating properties by dissolving a hydrolyzate of starch in water. CONSTITUTION:A hydrolyzate of starch represented by a general formula H(C6 H10O5)nOH is dissolved in water at ordinary temp. by 0.5-65wt.%, preferably 1-50wt.%. A water soluble org. compd. such as propylene glycol as a wetting agent is further dissolved by 0.1-50wt.% as required and the viscosity of the resulting soln. is regulated to 2-30cps to obtain a treating agent for stripping an asbestos layer. Since the treating agent has a great affinity for water, moderate viscosity and superior penetrating property, it penetrates perfectly into a thick asbestos layer having low water absorbing property. The treating agent does not scatter as dust and is poisonless, so work efficiency is considerably increased.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is for applying a layer to an old Ashes 1, which has been blown to the surface of a structure such as a building for the purpose of heat insulation. The present invention relates to a processing agent for peeling and removal.

(Prior Art) In recent years, asbestos has been increasingly recognized as one of the substances that cause cancer.

Therefore, work is being carried out in various places to peel and remove old asbestos construction layers that were installed in school buildings and other buildings.

However, when carrying out this peeling work, a large amount of dust-like Ashes 1- will fly around, so it is necessary to spray water on the Ashes 1 layer to wet it before starting the work. It was being done.

However, simple water is azuhes 1~5c+n thick.
Since it is difficult to penetrate deep into the layer,
In order to improve this point, U.S. Pat. No. 1 discloses a technique for use as a treatment agent for peeling off a construction layer.

(Invention or problem to be solved) However, asbestos layer spraying is a construction method that
In the United States, gypsum is mainly used as a binding material for asbestos, whereas in Japan, por 1 - lan 1 - cement 1 -
Due to the fact that the asbestos layer has poor water absorption, the above-mentioned treatment agent has insufficient adhesion to the surface of the asbestos layer and insufficient penetration into the asbestos layer.
Prior to the peeling work, penetration into the Azhes 1 layer was carried out for 1 minute.

Therefore, the object of the present invention is to provide excellent adhesion and permeability to ashest layers using cement 1~ as a binding material.
Another object of the present invention is to provide a treatment agent for removing Azhes 1 to construction layers that is difficult to evaporate.

[Structure of the Invention] (Means for Solving the Problems) The treatment agent for peeling an asbestos construction layer according to the present invention has the following properties: Consists of an aqueous solution containing the product.

The content of starch hydrolysis products in the aqueous solution is 0.5
~65% by weight, preferably 1~50% by weight.

A water-soluble organic compound as a wetting agent is added to the aqueous solution as necessary.

The viscosity of the aqueous solution is adjusted to 2 to 30 cps.

(Function) When the asbestos construction layer stripping treatment agent is sprayed onto the surface of the asbestos layer to be stripped, the stripping treatment agent adheres to the surface of the asbestos layer and does not drip easily. Since this removal treatment agent has penetrating properties, it can penetrate deep into the asbestos layer while it is attached, and the removal treatment agent can cover the entire asbestos layer without wetting it. Ru.

If the content of starch hydrolysis products in the stripping agent as an aqueous solution is less than 0.5% by weight, the viscosity of the aqueous solution will be too low and the adhesion will be insufficient when sprayed onto the asbestos layer. It is easy to drip, and if the aqueous solution exceeds 65%, the viscosity of the aqueous solution increases, making it difficult to penetrate into the asbestos layer.

The content of the aqueous organic compound in the aqueous solution is 0.
If it is less than 5% by weight, it will hardly be effective as a wetting agent that helps the I\ removal treatment agent permeate into the asbestos layer and suppresses the evaporation of water from the permeated removal treatment agent.
If it is more than 0% by weight, a problem arises in that the solubility of the starch hydrolysis product in the aqueous solution is reduced.

If the viscosity of the stripping agent is less than 2 cps, the stripping agent will penetrate into the asbestos layer too quickly, causing problems such as the stripping agent being absorbed by the asbestos layer construction base.
Moreover, when it becomes 30 cps or more, it becomes difficult for the peeling treatment agent to penetrate into the asbestos layer.

(Examples) Some preferred examples of the present invention will be described below.

First Example A treatment agent for removing an asbestos construction layer was prepared by dissolving each raw material in water at room temperature using the following raw material formulation.

PINE-DEX #1 10% by weight propylene glycol 20 points water 70 points PINE-DEX #1 is a starch hydrolysis product manufactured by Matsutani Kagaku Wholesale, and is a starch α-1
, 4 bonds and α-1,6 bonds, and has the general formula H (C6H
l. It has a structure represented by 0s)nO5)nOH and exhibits good hydrophilicity due to hydrogen bonding with water molecules. Then, there are several types with different numbers of ■, for example #1-#
Types of 6 are commercially available, and those with a value of 11 or smaller have a stronger affinity for water-soaking. A value of 11 to 13 is suitable for the present invention. This type of starch hydrolysis product is, of course, hygienically harmless and is widely used as an additive in the food, pharmaceutical, and other industrial fields.

On the other hand, propylene glycol is asbestos layer I\7
+'l It was blended as a wetting agent that promotes the penetration of the painting processing agent and suppresses the evaporation of water.

The prepared ThU release treatment agent had a viscosity of 6 cps at 25°C, and was sprayed using an air toss spray can under the spray pressure of 150 k)</c+ port 2.
The sample was sprayed at a rate of about 0.5N per 1102 on the first layer of Amehesu with a thickness of about 3 cm per layer. and,
After spraying, I left it for about 30 minutes to allow the stripping agent to fully penetrate into the Ashes 1 layer, and then I carried out the stripping work using a scraping tool for Ashes 1. 1~
No dust scattering was observed at all. Even after approximately 72 years had passed since the start of the peeling operation, the sheets were still wet with the Amehesu 1-Layer Release Processing Agent.

Prior to the start of work, the work area was covered with polyethylene sheets, etc., as in the past, and workers wore protective equipment such as dust masks to ensure safety.

The treatment agent for removing asbestos construction layers according to the above-mentioned formulation has good adhesion to the surface of the asbestos layer due to the high water affinity of the starch hydrolysis product, and propylene glycol as a wetting agent. Due to the penetration promoting effect exhibited, there was less tendency for dripping from the surface of the asbestos layer after spraying compared to conventional products, and almost no water evaporated for more than 72 hours after penetration.

Even when the construction base of the asbestos layer is porous, such as cellular concrete, the amount of penetration into the construction base is small because the peeling treatment agent has an appropriate viscosity.

Second example The stripping treatment agent was prepared using the following raw material formulation.

PINE-DEX #: 3 5% by weight glycerin 2.

The viscosity of the water 93 horns prepared g+11 Rikawa treatment agent is 4 cps (25
°C), and when this was used in the same manner as in the first example,
Substantially the same effects as in the first embodiment were obtained.

Third embodiment A processing agent for pickled paintings was prepared using the following raw material composition.

1” INE-DEX #1
15% by weight F'1NE-DEX #6
10 Horn propylene glycol
3Q II 45 horns of water The viscosity of the prepared stripping agent is 25 cps (25°C)
Met. The penetration rate of asbestos layer I\ is the first and second
Although it was slightly lower than that of the example, a sufficient effect of suppressing water evaporation from the asbestos layer was obtained.

Fourth example The stripping treatment agent was prepared using the following raw material formulation.

The viscosity of the peeling agent is 0.4 cl + 5 (2
5°C). Even with this raw material combination, the adhesion and permeability of the asbestos layer required for construction were sufficiently achieved.

In addition to the above, examples of water-soluble organic compounds include monohydric alcohols such as methanol, ethanol, isopropyl alcohol, acetate, methyl ethyl alcohol, etc., if odor or toxicity is not a particular problem. Ketones such as ethyl cellosolve, butyl cellosolve, n-propyl cellosolve, etc., or cal-1-ols can also be used.

In order to adjust the viscosity of the stripping treatment agent to a desired value, it is necessary to use various water-soluble organic polymer compounds with thickening properties other than starch hydrolysis products, such as methylcellulose, carboxydimethylcellulose, Hydroxyethyl cellulose, sodium alginate, polyvinyl methyl ether, polyvinyl methyl ether/maleic anhydride copolymer resin, polyvinyl alcohol, sodium polycarboxylate, etc. may be blended. Furthermore, if necessary, various surfactants and preservatives may be added to increase permeability, which has the excellent effect of greatly improving workability.

is obtained.

[Effects of the Invention] As is clear from the above explanation, the treatment agent for removing asbestos construction layers of the present invention, which is made of an aqueous solution of a starch hydrolysis product, has excellent water affinity, appropriate viscosity, and penetration resistance. Unlike conventional products, when sprayed onto the surface of an asbestos layer, it easily adheres to the surface and rarely drips, and because it uses cement as a binding material, it has poor water absorption. It completely penetrates deep inside even thick asbeth 1 to Ni.

Claims (6)

[Claims] (1) General formula H(C_6H_0_10O_5)_nOH
A treatment agent for removing an asbestos construction layer consisting of an aqueous solution containing a starch hydrolysis product represented by: (2) The treatment agent for peeling an asbestos construction layer according to claim 1, characterized in that the content of the starch hydrolysis product is 0.5 to 65% by weight, preferably 1 to 50% by weight. (3) The treatment agent for peeling an asbestos construction layer according to claim 1 or 2, characterized in that a water-soluble organic compound other than a starch hydrolysis product is added as a wetting agent. (4) The treatment for peeling off the asbestos construction layer according to claim 3, wherein the water-soluble organic compound is monohydric or polyhydric alcohol, ketone, glycol, cellosolve, carbitol, etc. agent. (5) The content of water-soluble organic compounds in the aqueous solution is from 0.1 to
The treatment agent for peeling an asbestos construction layer according to claim 3 or 4, characterized in that the amount is 50% by weight. (6) The treatment agent for peeling an asbestos construction layer according to any one of claims 1 to 5, wherein the aqueous solution has a viscosity of 2 to 30 cps.