JPS648654B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION The present invention relates to a modified coating fluid used to form an insulating buffer layer between shotcrete and lining concrete in tunnel inner wall formation. More specifically, the present invention is a recent tunnel construction method in which, after excavating the ground, shotcrete is applied to the excavated surface, the surface of the excavated ground is stabilized with rock bolts and steel arch support, and then lining is applied. When pouring concrete, cracks in the lining concrete cause deterioration in appearance, as well as safety issues caused by water leakage and peeling. As a way to solve these problems, a method is used to form an insulating buffer layer between the shotcrete and lining concrete. This invention relates to a coating liquid for the purpose of improving defects originating from the rubber asphalt emulsion used in the present invention. Prior art In the construction of mountain tunnels, after excavating the ground, shotcrete is first applied to the excavated surface as a primary lining, and if necessary, rock bolts and steel arch supports are combined to stabilize the ground. A commonly used construction method is to assemble movable steel formwork and then pour concrete lining into the air between the shotcrete and the formwork. However, in this construction method, the lining concrete is in close contact with the sufficiently hardened shotcrete, so the volume changes that occur in the lining concrete, such as expansion during gelation and contraction during hardening, cause cracks in the lining concrete after hardening. to occur. In addition, even after the lining concrete has hardened, the temperature difference between the shotcrete and lining concrete inside the tunnel is
This appears as a difference in the amount of thermal expansion and contraction between the shotcrete and lining concrete, and this causes cracks in the lining concrete. Cracks not only spoil the appearance of the tunnel, but also cause water leakage and, in some cases, the concrete lining falling off. As mentioned above, there are various causes of cracks in concrete lining, but the best way to solve this problem is to eliminate the close contact between shotcrete and concrete lining, so that both can expand and contract freely without being constrained by others. It is to do so. As a countermeasure to this problem, a construction method has been adopted in which a rubber asphalt emulsion is applied at an intermediate stage between the construction of shotcrete concrete and lining concrete to form an intermediate layer that insulates the two. In this sense, in the present invention, this intermediate layer is expressed as an insulating buffer layer. As is clear from the above explanation, it is inevitable from the perspective of painting that the insulating buffer layer adheres closely to the shotcrete as the primary lining, but as a secondary lining, it is necessary to adhere the insulating buffer layer to the shotcrete as a secondary lining. There is no question of whether or not it will adhere to the lining concrete that will be poured into the space. In either case, it is possible to prevent cracks from occurring in the lining concrete, but it is rather preferable that the lining not be in close contact with the lining concrete and that voids be left. The reason for this is that leaving voids reduces the stress relaxation ability required of the insulating buffer layer and the elasticity required for it.
However, leaving voids is not something that can be done freely, so the insulating buffer layer must have elasticity, permanence, and durability to cope with the situation where the lining concrete comes into close contact with the layer. Become. Although the conventional use of rubber asphalt emulsion satisfies the above points to some extent, its performance is still insufficient, and there are still several issues to be solved when considering the process of construction at work sites. There is. In other words, when conventional coating liquids containing rubber asphalt as the main component are used, a bad odor is generated during spraying, which has a considerable negative impact on the hygiene of workers in narrow tunnels with poor air circulation. In addition, the ground of the workshop is dyed with live stains due to the rubber asphalt emulsion sprayed on the shotcrete falling off the painted surface. Furthermore, since rubber asphalt emulsion is black, when used in a dimly lit area inside a tunnel, it is difficult to distinguish between coated areas and uncoated areas, which can easily cause construction defects. In addition, asbestos fibers mixed with various types of hydration hardening cements, or these mixed with acrylic emulsions, have been trialled to improve the strength of the coating, improve economic efficiency, and provide thick coatings with one coat. However, cement mixtures lack preservability, so mixing must be done at the work site, which is cumbersome and has a limited pot life. In the past, it was considered that plasticizers were added to polyvinyl acetate emulsion to give it film-forming properties and flexibility. It became brittle and could not maintain its durability. Purpose of the Invention The present invention aims to solve the problems of the above-mentioned current state of the art, particularly when a coating liquid containing rubber asphalt emulsion or hydration-hardening cement is used to form the above-mentioned insulating buffer layer. It is. Summary of the Invention The present invention is characterized in that the composition of the dispersed phase is 40 to 5 parts by weight of ethylene, 60 to 95 parts by weight of vinyl acetate, and the number of carbon atoms is 9 to 11.
an aqueous emulsion obtained by emulsion polymerization consisting of 60 to 0 parts by weight of a branched fatty acid vinyl ester (A), a pigment and/or a filler that does not have hydration curability (B), and a viscosity imparting agent (C). ), the coating liquid has a viscosity of 20,000 to 150,000 at 30°C and 10 rpm as measured using a BH type rotational viscometer.
centipoise (cps), and the value obtained by dividing the viscosity at 30°C and 2 rpm measured using a BH type rotational viscometer by the viscosity at 30°C and 20 rpm is in the range of 3.0 to 8.0. A coating solution for forming an insulating buffer layer on an inner wall of a tunnel, characterized in that the volume fraction of the resin solid content of the aqueous emulsion (A) in the dry coating film of the coating solution is 40% or more. Description of preferred embodiments of the invention The aqueous emulsion (A) used for preparing the coating solution of the present invention includes (1) ethylene content of 40 to 40%
5 parts by weight of ethylene-vinyl acetate copolymer and 60 to 95 parts by weight of vinyl acetate, preferably 30 to 10 parts by weight of ethylene and 70 to 90 parts by weight of vinyl acetate. can give. If the ethylene content is outside the above range, the coating film will be too flexible and the surface will be sticky, and the coating strength will be too low, making it undesirable as an insulating layer.If the ethylene content is too low, the film forming properties of the coating film will be poor. The material is flexible and cannot withstand the alkali that oozes out from shotcrete and lining concrete.Also, the coating film has a high tensile strength but has low elongation and cannot withstand the long-term expansion and contraction of concrete materials, so insulation buffering is required. It is unsuitable as a layer that does not play the role of preventing concrete from cracking or peeling. The aqueous emulsion (A) includes (2) 40 to 5 parts by weight of ethylene, 60 to 95 parts by weight of vinyl acetate, and 60 to 60 parts of vinyl ester of branched fatty acid having 9 to 11 carbon atoms.
0 parts by weight, for example 60 to 0.5 parts by weight of a terpolymer emulsion, preferably 30 to 10 parts by weight of ethylene.
Parts by weight, vinyl acetate 70-90 parts by weight, carbon number 9-9
Examples include copolymer emulsions containing 50 to 10 parts by weight of vinyl esters of 11 branched fatty acids. If the ethylene content is higher than the above range, the coating film will be sticky, have low tensile strength, and have too high elongation, resulting in a weak coating film. On the other hand, if the amount of vinyl acetate is too large, the coating film will be hard, brittle, and have poor alkali resistance, which is unsuitable. The vinyl ester of a branched fatty acid having 9 to 11 carbon atoms should be used in an amount of 60 to 0 parts by weight, for example, 60 to 0.5 parts by weight, preferably 50 to 10 parts by weight; if it is too large, the coating film will be too soft and unsuitable. be. Vinyl esters of branched fatty acids having 9 to 11 carbon atoms include Beoba 10 (trade name of Ciel Chemical Co., Ltd.), which is a vinyl ester of versatic acid, and nonane vinyl ester. Beoba 10 referred to here is a vinyl ester of a synthetic fatty acid with 9 to 11 carbon atoms (10 on average), and its chemical structural formula is as follows: (In the above formula, R ₁ , R ₂ and R ₃ are linear alkyl groups, one of which is a methyl group).
Tertiary nonane vinyl ester can also be represented by a chemical structural formula similar to Beoba 10. Since these vinyl esters of branched fatty acids having 9 to 11 carbon atoms have a large number of carbon atoms and a bulky structure, they can be copolymerized with ethylene-vinyl acetate, etc. to impart further water resistance and alkali resistance to the above-mentioned insulating layer. It is a preferred raw material. These copolymer emulsions (A) are produced in forms known to those skilled in the art, such as a protective colloid system, a surfactant system, a combination system of both a protective colloid and a surfactant, and a soap-free system. The protective colloid emulsion is obtained by emulsion polymerization of monomers having the above composition range in an aqueous medium in the presence of a polymerization initiator and a protective colloid. The amount of protective colloid used may range from 1 to 10 parts by weight based on the emulsion copolymer resin (solid content), and in particular, 2 to 5 parts by weight when polyvinyl alcohol and hydroxyethyl cellulose are used as the protective colloid. preferable. The surfactant emulsion can be obtained in the same manner as the protective colloid emulsion described above. The amount of surfactant used may range from 1 to 10 parts by weight based on the monomer. In addition to these protective colloid-based emulsions and surfactant-based emulsions, emulsions based on a combination of a protective colloid and a surfactant are also used. Furthermore, the same applies to those in which a surfactant is subsequently added to a protective colloid emulsion. Protective colloids that can be used in these emulsions include fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, other derivatives of polyvinyl alcohol, polyacrylamide and its modified products, polyvinylpyrrolidone, other water-soluble synthetic polymers, methylcellulose, hydroxyethylpropyl. Water-soluble natural products such as cellulose, cellulose derivatives such as hydroxyethylcellulose, starch or its derivatives, gelatin, casein, and soybean protein are preferred, and among these, polyvinyl alcohol and hydroxyethylcellulose are preferred, and these can be grafted onto polymers or adsorbed onto emulsion particles. It stabilizes the emulsion and forms a tough film. Surfactants include anionic, nonionic,
Cationic types include higher alcohol sulfate ester salts, alkylbenzene sulfonates, polyoxyethylene alkylphenol sulfate salts, dialkyl sulfosuccinates, etc., and nonionic types include polyoxyethylene alkyl ether, polyoxy Examples include ethylene alkyl phenol ether, oxyethylene-oxypropylene block copolymer, and oxyethylene sorbitan monolaurate. Examples of cationic compounds include laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, distearyldimethylammonium chloride, and alkylbenzyldimethylammonium chloride. In addition, without using any surfactants or protective colloids, sodium vinylsulfonate, sodium methalylsulfonate, 2-acrylamide 2-methylpropanesulfonic acid, acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, etc. The same is possible with soap-free emulsions made using so-called reactive surfactants that are copolymerizable with vinyl monomers, or using hydrophilic oligomers. In preparing the aqueous emulsion (A), it is also preferable to copolymerize a small amount of a monomer having self-crosslinking properties in order to improve the toughness of the coating film, that is, the insulating buffer layer. Examples of monomers having self-crosslinking properties include N-methylol acrylamide, glycidyl acrylate, glycidyl methacrylate, divinylbenzene, triallyl cyanurate, diallyl phosphate, 2-hydroxyethyl acrylate, and 2-hydroxyethyl methacrylate. Furthermore, addition of a small amount of various crosslinkable resins such as urea resin, melamine resin, polyamide amine epichlorohydrin resin, epoxy resin, etc. to the above water-based emulsion (A) can also impart a three-dimensional crosslinked structure to the coating film. It is effective in increasing the toughness of the film, imparting water resistance and alkali resistance to the coating film, and imparting physical properties desirable as an insulating buffer layer. Pigments used in the present invention and fillers (B) that do not have hydration hardening properties include various colored pigments such as titanium oxide, extender pigments such as kaolin, clay, various calcium carbonates, and barium sulfate. Any pigment known to those skilled in the art may be used, and fillers such as silica powder, sand such as silica stone, and aggregates may also be used in combination. If the coating liquid sag due to these high specific gravity fillers, use plastic fibers, glass fibers, wollastonite, diatomaceous earth, wood flour, rice hull powder, cork powder, micro balloons, and shirasu balloons as lightweight fillers. , resin powder, asbestos powder, and other fillers that do not have hydration hardening properties, such as mineral slag, can be used in combination or alone. Further, the viscosity imparting agent (C) in the present invention is an essential component for imparting smoothness to the coating liquid and preventing sagging.
Those that can be used include natural polymeric thickeners such as gelatin, casein, semi-synthetic polymeric thickeners such as oxidized, methylated, carboxymethylated, hydroxyethylated, hydroxypropylated, phosphorylated, and cationic. starch or cellulose that has been treated with chemical treatment; alginic acid; or sodium alginate (ammonium); synthetic polymer thickeners such as polyvinyl alcohol, polyvinylpyrrolidone, sodium polyacrylate, polyacrylamide, and surfactant thickeners. Agents include polyethylene oxide, polyethylene glycol ether, inorganic thickeners such as colloidal silica, bentonite, Atagel (manufactured by Engelhard Minerals and Chemicals, aluminum silicate type)
etc. can be mentioned. The viscosity of coating liquids using these thickeners at 30°C and 10 rpm measured using a BH-type rotational viscometer is 20,000 centipoise (cps) to 150,000 cps: and the viscosity is 30% as measured using a BH-type rotational viscometer °C,
The value obtained by dividing the viscosity at 2 rpm by the viscosity at 20 rpm at 30°C (hereinafter referred to as the thixotropic index) is
It is best to adjust it to be in the range of 3.0 to 8.0.
If the viscosity of the coating liquid is too high outside the above range, the coating workability by spraying etc. will be poor and the coating surface will be highly uneven and lack uniformity as an insulating buffer layer. On the other hand, if the viscosity of the coating liquid is too low outside the above range, the coating workability is good, but the coating liquid tends to sag, and this tendency is particularly strong on wet surfaces, and it does not function as an insulating buffer layer. . If the thixotropy index is too low outside the above range, the atomization properties of the coating liquid during spraying will be poor, resulting in an uneven painted surface and sagging, which will significantly impede the function of the insulating buffer layer. It is inappropriate to do so. On the other hand, if this value is too high outside the above range, the thixotropy of the coating liquid will be too strong, making it troublesome to transfer the coating liquid to a hopper during on-site work, and when using a brush or roller. In the case of painting, the paint film lacks durability, and the painted surface has streaks, making it unsuitable for use as an insulating buffer layer due to lack of uniformity. The volume fraction of resin solids (hereinafter referred to as RVC) of the aqueous emulsion (A) in the dried coating film of the coating solution of the present invention, that is, the insulating buffer layer, is required to be 40% or more. When the RVC is lower than 40%, the elongation of the coating film is low, and it lacks the ability to follow the expansion and contraction of concrete over a long period of time, and therefore cannot sufficiently fulfill its role in preventing cracks in the lining concrete. Furthermore, the addition of pigments imparts appropriate viscosity to the coating solution, improves coating workability, and at the same time increases the solid content of the coating material, which is useful for preventing cracks due to volume shrinkage during drying. The concentration of the coating liquid may be arbitrary, but common sense suggests that it is preferably within the range of 50 to 85%. If the concentration of the coating liquid is low, fading and cracks are likely to occur due to volumetric shrinkage during drying, and conversely, if it is too high, the workability of spraying etc. will be poor and the painted surface will not be smooth. Chips and a decrease in adhesion strength to shotcrete were also observed, and both were unsuitable as they did not play the role of an insulating buffer layer. In the present invention, the aqueous emulsion (A) and the coating liquid include a common synthetic resin emulsion,
and antifoaming agents added to the same emulsion paints,
Coating aids, plasticizers, dispersants, freeze stabilizers, preservatives, antifungal agents, and the like are added as necessary. The coating solution of the present invention can be applied to shotcrete by either spraying or various rollers.
For spraying, you can use a ricing gun, mastic gun, mortar gun, etc., but you can also use air spray, airless spray, or a combination of air and airless sprays.Among these, the combination of air and airless sprays have the best atomization.
The coated surface is smooth and the discharge amount is large and efficient. The coating fluid of the present invention has extremely good workability in spraying, etc., has no problems with odor, and has a smooth finish on the painted surface.The coating film has high elongation and is also water resistant, alkali resistant, durable, etc. Because of its excellent properties, it is extremely effective as an insulating buffer layer between shotcrete and lining concrete during tunnel construction to prevent cracking of lining concrete, and therefore to prevent water leakage and spalling. In addition, the coating fluid of the present invention shows very little change in its condition and viscosity even after long-term storage of 6 months to 1 year, has extremely good coating workability just like it did immediately after production, has no odor problems, and has a good finish on painted surfaces. is smooth and has excellent coating film elongation, water resistance, and alkali resistance. Therefore, since the pot life is extremely long, the trouble of preparing the coating liquid on-site can be omitted. Effects of the Invention The coating liquid of the present invention has the following various features. (1) Less odor is generated during painting work at the construction site. This is due to the fact that various polymerizable monomers having low odor and good copolymerizability were selected and used in producing the aqueous emulsion to be incorporated into the coating solution. As a result, it is very favorable for field workers who have been bothered by the foul odor of rubber asphalt emulsions. (2) Good painting workability at the construction site. In other words, the brush and roller slide easily, the nozzle does not get clogged when spraying, and atomization is good.As a result, the operator can apply a larger amount of coating liquid within the specified time, and the coating process is easier. In addition to reducing the number of man-hours, it also makes it easier to obtain a smooth coated surface, making it easier to keep the thickness of the coated film uniform over the entire surface. This is due to the fact that the viscosity behavior of the coating liquid is set within a specific range. (3) No dripping of coating fluid from the construction surface. Furthermore, even if a thick coating is applied to the ceiling surface, the coating will not fall off.
This is due to the viscosity behavior of the coating fluid set in a specific range, and as a result, it not only speeds up the painting process, but also prevents the work site from being contaminated by dripping or fallen coating fluid, making it easier to use afterwards. This makes the painting process more efficient, as there is no need for cleaning or removal work. (4) The applied coating liquid dries and solidifies quickly. This is probably because the water content of the coating liquid is kept low, but it also appears that the viscosity behavior of the coating liquid has an effect. This shortens the painting process and the time required to pour concrete for the secondary lining. (5) The coating liquid has good storage stability and can withstand long-term storage. Therefore, it can be applied on-site using the undiluted solution, contributing to a reduction in on-site work hours. (6) The coating solution can be applied even when the area to be coated is wet with water, and does not come off as seen in the case of rubber asphalt emulsions. (7) The coating liquid has a milky white color characteristic of water-based emulsions, so even under dim lighting in a tunnel, it will not leave unfinished areas that tend to occur with black rubber asphalt emulsions. (8) The coating film obtained by drying and solidifying the coating liquid is interposed between the shotcrete as the primary lining and the lining concrete as the secondary lining in this construction method, and is used to provide the above-mentioned insulation. It has the performance required for a buffer layer, that is, well-balanced strength and elongation, as well as water resistance combined with alkali resistance. As described above, the coating liquid of the present invention can be used as a material for forming an insulating buffer layer between the primary lining shotcrete and the secondary lining concrete in the tunnel construction process, which is currently an issue of improvement. This solution solves all the drawbacks of coating fluids containing emulsions or various hydration hardening cements. Next, the present invention will be specifically explained with reference to Examples. The strength and elongation at break of the films and coatings in the following examples are values measured at 20°C and 65% RH (chuck spacing 20mm, tensile speed 200mm/min). Example 1 Protective colloid (resin content
Ethylene-vinyl acetate copolymer emulsion (hereinafter referred to as EVA) (vinyl acetate 85% by weight, ethylene 15% by weight, emulsion concentration 55% by weight, viscosity 3000 cps (BH type rotational viscometer 30)
℃, 10 rpm)) as a vehicle, a coating solution was prepared with the following formulation. Vehicle: 100 parts by weight Dispersant: 10% by weight aqueous sodium hexametaphosphate aqueous solution 4 parts by weight Extender: Calcium carbonate NS-100 (Nitto Funka
Co., Ltd.) 50 parts by weight Viscosifier: Colloidal silica (Erosil:
(manufactured by Dexa, West Germany) 2 parts by weight Coating liquid concentration 69% by weight, coating liquid viscosity 100000cps
(BH type rotational viscometer 30℃, 10rpm) Thixotropy index = 5.8 RVC = 73% Apply the above coating solution on a glass plate at 20℃ and 65%RH.
The tensile strength of the coating film dried for one day was 37.4 Kg/cm ² and the elongation at break was 300%. In addition, the swelling rate of the same coating film after being immersed in 20℃ water and 2% caustic soda aqueous solution for 4 days (swelling rate = W ₂ - W ₁ /W ₁ × 100 (%) W ₁ : Weight of coating film before immersion , _W2 : coating weight after immersion) is 12.7% and
At 8.6%, the elution rate (elution rate = W ₁ - W ₃ / W ₁ × 100 (%), W ₃ : coating weight after drying at 60°C for 3 hours after measuring the swelling rate)
were 3.2% and 3.7%, respectively. Next, a concrete block (30 cm long x 30 cm wide x thick) with coating characteristics equivalent to shotcrete was coated with the above coating solution and placed at an angle of 45° with respect to the horizontal surface.
15cm) Mighty Sprayer (Ito Sangyo Co., Ltd.)
The composition was sprayed using a nozzle diameter of 7 mm, a discharge pressure of 2 kg/cm ² , and a compressor pressure of 8 kg/cm ² to give a wet film thickness of 4 mm. As a result, the coating workability and atomization state were very good, the surface condition of the coating film was smooth, there was no problem with odor during coating, there was no dripping of the coating solution, and there was extremely little pollution of the surrounding environment. In addition, the coating liquid of the present invention shows very little change in its condition and viscosity even after long-term storage for six months or one year, and the coating workability is as good as immediately after production, and the surface condition of the coating film is smooth. There was no problem with odor, no dripping, and there was very little environmental pollution. Example 2 Nonionic surfactant (manufactured by Kao Soap Co., Ltd., Emulgen 950, using 3% by weight of resin content) and anionic surfactant (manufactured by Kao Soap Co., Ltd., Lebenol WZ, using 0.2% by weight of resin content) ) and partially saponified polyvinyl alcohol with a degree of polymerization of 1700 and a degree of saponification of 88 mol% (Kuraray Poval 217, resin content of 0.2% by weight) was used to produce EVA with a monomer composition as shown in Table 1 below (emulsion concentration 58% by weight, viscosity 1500cps (BH type rotational viscometer
A coating solution was prepared in the same manner as in Example 1 using the following formulation as shown in Table 1 using 30° C., 10 rpm) as a vehicle. The properties of the coating liquid and various coating film performances are shown in Example 1.
I asked for exactly the same thing. Furthermore, coating with the coating liquid was carried out in exactly the same manner as in Example 1. These results are shown in Table 1. Examples 3 to 8 Nonionic surfactant (Emulgen 950 manufactured by Kao Soap Co., Ltd., resin content 1.2% by weight) and anionic surfactant [Levesol WZ manufactured by Kao Soap Co., Ltd., resin content 0.5% by weight] Examples 3 to 8 in Table 1 using
Vinyl acetate-ethylene- with a monomer composition such as
Beova 10 terpolymer emulsion (emulsion concentration 55% by weight, viscosity 3000 cps (BH type rotational viscometer)
Using this as a vehicle, a coating solution was prepared in the same manner as in Example 1 with the formulation shown in Table 1. The properties of these coating solutions and various coating film performances were determined in exactly the same manner as in Example 1. Furthermore, coating with the coating liquid was carried out in exactly the same manner as in Example 1. These results are shown in Table 1. Comparative Example 1 Same as Example 2 Nonionic surfactant [Kao Soap
Made by Co., Ltd., Emulgen 950, using 3% resin by weight]
and anionic surfactant [Levesol manufactured by Kao Soap Co., Ltd.]
WZ, using 0.2% by weight of resin content] and partially saponified polyvinyl alcohol with a degree of polymerization of 1700 and a degree of saponification of 88 mol% (using Kuraray Poval 217, 0.2% by weight of resin content)
A polymer emulsion containing vinyl acetate alone as a monomer (emulsion concentration 55% by weight, viscosity 3300 cps (BH type rotational viscometer, 30°C, 10 rpm) was prepared using the same method as in Comparative Example 1 in Table 1, and this was used as a vehicle. 2% by weight of dibutyl phthalate as a plasticizer was added to this to prepare a coating solution with the same formulation as in Example 1.The properties of the coating solution and various coating film performances were evaluated in Example 1.
I asked for exactly the same thing. Furthermore, coating with the coating liquid was carried out in exactly the same manner as in Example 1. These results are shown in Table 1. Comparative Example 2 A rubber asphalt emulsion was sprayed in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 3 Using the same resin as in Example 1 as a vehicle, the coating liquid was
A coating solution was prepared that was exactly the same as in Example 1 except that the RVC was changed to 35%. The properties of the coating liquid and various coating film performances are shown in Example 1.
I asked for exactly the same thing. Furthermore, coating with the coating liquid was carried out in exactly the same manner as in Example 1. These results are shown in Table 1. Comparative Example 4 Using a commercially available acrylic ester polymer emulsion (resin solid content: 50% by weight), a coating liquid was prepared by blending white Portland cement as shown in Table 1. The properties of the coating liquid and various coating film performances were determined in exactly the same manner as in Example 1. Furthermore, coating with the coating liquid was carried out in exactly the same manner as in Example 1. These results are shown in Table 1. Comparative Examples 5 to 12 Using the same resin as in Example 1 as a vehicle, the amounts of the dispersant, extender, viscosity imparting agent, and viscosity adjusting water in the coating liquid were varied as shown in Table 1, and the amounts of the coating liquid were changed. Coating liquids with varying viscosity and thixotropy index were prepared. Regarding these, the properties of each coating liquid and various coating film performances were also evaluated in Example 1.
I asked for exactly the same thing. Further, the coating with the coating liquid was carried out in exactly the same manner as in Example 1. These results are shown in Table 1. From these results, a coating liquid having the viscosity, thixotropy index, and RVC as specified in the claims of this patent using the EVM of the present invention and the vinyl acetate-ethylene-Beova 10 terpolymer emulsion as a vehicle can be obtained. showed very excellent coating performance, coating workability, and storage stability.However, the coating solution using vinyl acetate polymer emulsion as a vehicle had low elongation despite its high coating strength. Furthermore, the water resistance and alkali resistance are extremely poor, and even if the vehicle composition is within the scope of this patent claim, the coating liquid
If the RVC is below the lower limit of the claimed scope, there will be the same drawbacks as the coating film of the coating liquid using vinyl acetate as the vehicle, and the viscosity and/or thixotropy index of the coating liquid will be affected. , or both outside the scope of this patent claim, the coating performance such as coating workability, sagging of the coating liquid, and surface condition of the coating film will be poor, and all of these will prevent cracking of the concrete lining of the tunnel inner wall for a long period of time. It was not suitable for long-term use. On the other hand, rubber asphalt emulsion had extremely poor painting workability, had a strong odor during painting, had a highly uneven coating film surface, and was black, causing significant environmental pollution. Furthermore, acrylic acid ester polymer emulsion mixed with hydration-hardening cement material has poor coating workability, strong pungent odor, and poor coating performance such as uneven coating surface condition. It had a fatal flaw as a construction material, as the coating solution gelled within a few hours after preparation, which meant that it had an extremely short pot life, was laborious to prepare on-site, and was extremely difficult to work with.

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Claims (1)

[Claims] 1. An aqueous emulsion obtained by emulsion polymerization in which the composition of the dispersed phase is 40 to 5 parts by weight of ethylene, 60 to 95 parts by weight of vinyl acetate, and 60 to 0 parts by weight of vinyl ester of a branched fatty acid having 9 to 11 carbon atoms.
(A), a pigment and/or a filler that does not have hydration curability (B), and a viscosity imparting agent (C); The viscosity at 30°C and 10 rpm measured using a BH-type rotational viscometer is in the range of 20,000 to 150,000 centipoise, and the value obtained by dividing the viscosity at 30°C and 2 rpm measured using a BH type rotational viscometer by the viscosity at 30°C and 20 rpm is 3.0.
~8.0, and furthermore, the volume fraction of the solid resin content of the aqueous emulsion (A) in the dry coating film of the coating solution is 40% or more. Industrial fluid.