JPH07268167A - Water-proofing material composition - Google Patents

Abstract

PURPOSE:To provide a water-based water-proofing material composition giving a coating film having excellent water-resistance, followability to substrate crack and adhesivity under wet condition and free from tackiness. CONSTITUTION:This water-proofing material composition is composed of an inorganic hydraulic substance and an emulsion produced by emulsifying and dispersing a polymer containing 30-98wt.% of one or more monomers selected from alkyl (meth)acrylates having 4-10C alkyl group, 0.1-3wt.% of (meth)acrylic acid and 0.1-5wt.% of glycidyl (meth)acrylate as essential constituent monomers and having a glass transition temperature of <=-20 deg.C in water in the presence of a cationic or nonionic surfactant. The invention also relates to a water-proofing material composition for a water-storage tank composed of the above composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof material composition, particularly useful as an inner waterproof material for a structure having a water collecting structure such as a water tank for sewage and sewage, a pit, and civil engineering construction. It can be widely used in the field.

[0002]

2. Description of the Related Art Water tanks for water supply and sewerage made of concrete are caused by cracks in concrete.
It often causes a water leak accident. As a countermeasure, usually, a treatment of applying a waterproof material composition to the inner surface of the tank is often used. The waterproof material composition to be applied to the inner surface of the water storage tank is required to have its coating film excellent in conformability to cracking of the base, and since the coating film of the waterproof material composition is constantly in contact with water, It is required to have excellent properties and to firmly adhere to the base even under a wet condition caused by water that permeates between the base and the coating film from the surface of concrete or the like. The term "following property of the base material cracks" as used herein means that when the base material is cracked due to hardening shrinkage of concrete or the like after the waterproof material composition has been applied, the coating film is broken due to the elongation of the waterproof material coating film caused thereby. It refers to the ability to flexibly follow. In the water tank waterproof material composition, further, this characteristic,
It is required that the coating film does not harden even under low-temperature conditions in winter, and that the coating film flexibly follows, and therefore, the coating film is required to have high flexibility. As the waterproof material composition used for this purpose,
Conventionally, those made of epoxy resin or ethylene vinyl acetate resin have been generally used.

[0003]

However, the epoxy resin-based waterproof material composition is an organic solvent-based waterproof material, and when it is used as a water tank waterproof material composition,
Since the inner surface of the tank has a fairly high degree of airtightness, the odor is harmful to the worker, and the amine compound used as the curing agent is toxic to the human body, which is not preferable for the safety and health of the worker. Further, the epoxy resin-based waterproofing material composition is not sufficient in flexibility of the coating film, not only cannot follow the cracks generated in the concrete of the foundation to cause water leakage, but also due to poor water resistance adhesion. As a result, blisters, cracks or peeling were likely to occur. On the other hand, an ethylene vinyl acetate resin-based waterproof material composition is used as an aqueous emulsion, and is generally used as a mixture with a cement-based filler. This waterproof material composition,
It is a water-based waterproof material, does not have the above-mentioned safety and health problems for workers, and due to its water-based material, it has relatively excellent adhesion to concrete under wet conditions. Due to the nature of the bi-based resin, there was a problem in water resistance, and swelling, peeling, etc. were caused by the swelling and softening of the coating film. The present inventors have studied other than these compositions, a combination of acrylic resin emulsion and various cement-based inorganic filler, the composition is water-based, the coating film is water resistant, It was found that the adhesiveness to the base and the crack-following property under wet conditions are superior to those of the above-mentioned waterproof material composition. However, the performance as a water tank is not sufficient, and the coating film may be tacked. If the coating film has tack, it will often ride on the coating film when painting the inner surface of the tank, and if the coating film tack is strong, the workability will be significantly impaired, and in the worst case, the waterproof membrane will be destroyed. There is a possibility that it will end up. The inventors of the present invention are water-based waterproofing material compositions, the coating film of which is excellent in water resistance, the ability of the base material to follow cracks, the adhesion to the underlying material under wet conditions, and the tacking-free waterproofing material composition. In order to find out, he conducted a thorough study.

[0004]

The present inventors have completed the present invention by finding that the above-mentioned problems can be solved by a composition obtained by mixing a certain specific acrylic resin emulsion and an inorganic hydraulic substance. That is, the present invention provides one or more monomers 3 selected from the alkyl (meth) acrylates having an alkyl group having 4 to 10 carbon atoms of the first invention.
0-98% by weight, (meth) acrylic acid 0.1-3% by weight
And glycidyl (meth) acrylate 0.1 to 5% by weight
Is an essential constituent monomer, and has a glass transition temperature of -20 ° C.
From the water-proofing material composition and the composition according to the second invention, characterized in that the following polymer comprises an emulsion in which water is emulsified and dispersed by a cationic or nonionic surfactant, and an inorganic hydraulic substance. The present invention relates to a water tank waterproof material composition. Hereinafter, the present invention will be described in detail.
In the present specification, acrylate and tacrylate are referred to as (meth) acrylate, and acrylic acid and methacrylic acid are referred to as (meth) acrylic acid.

Alkyl (meth) acrylate having an alkyl group having 4 to 10 carbon atoms In the present invention, the alkyl (meth) acrylate having an alkyl group having 4 to 10 carbon atoms is, for example, n-butyl (meth) acrylate. Acrylate, iso-butyl (meth) actlate, sec-butyl (meth) actrate, n-amyl (meth) actrate, iso-amyl (meth) actrate, n-hexyl (meth) actrate, n-heptyl (meth) actrate, Oxoheptyl (meth) actrate, n-octyl (meth) actrate, 2-ethylhexyl (meth) actrate, n-nonyl (meth) actrate, oxononyl (meth) actrate, n-decyl (meth) actrate, oxodecyl (meth) actrate Etc. A (meth) acrylate having an alkyl group having a carbon number of less than 4 is not preferable from the viewpoint of alkali resistance, while one having a carbon number of more than 10 is not preferable because cold resistance is deteriorated. The proportion of the above monomers in the total monomers is 30 to 98% by weight, and more preferably 40 to 9
It is 0% by weight. If this ratio is less than 30% by weight,
On the other hand, the coating film becomes poor in crack-following followability, water resistance and alkali resistance. On the other hand, when it exceeds 98% by weight, not only tackiness occurs in the coating film, but also a coating film having sufficient strength cannot be obtained.

○ (Meth) acrylic acid The (meth) acrylic acid used in the present invention acts as a cross-linking component with glycidyl (meth) acrylate which is another essential constituent monomer component in the polymer, and also in the emulsion and the inorganic water. When a curable substance is mixed, it imparts toughness to the coating film by forming internal crosslinks between polyvalent metal ions such as calcium ions in the inorganic water-curable substance and the carboxyl group, and further imparts kneading stability. It also works as a dispersant. The proportion of these total monomers is in the range of 0.1 to 3% by weight. If this proportion is less than 0.1% by weight, the adhesiveness will be reduced and the coating film will be tacky, while 3% by weight
If it exceeds the range, the water resistance and alkali resistance of the coating film are extremely lowered, and the tack of the coating film is increased, which is not preferable.

Glycidyl (meth) acrylate The glycidyl (meth) acrylate used in the present invention acts as a crosslinking component in the polymer and imparts toughness to the coating film. Glycidyl (meth) acrylate can be used in an arbitrary range of 0.1 to 5% by weight in all monomers, but it is preferable to use it in a range of 0.1 to 3% by weight from the viewpoint of polymerization operation. Good When the content of glycidyl methacrylate is less than 0.1% by weight, the adhesiveness is lowered and the coating film becomes tacky. On the other hand, when it is used in excess of 5% by weight, not only the toughness of the coating film becomes too great. However, it is not preferable because agglomerates are likely to occur in the polymerization operation.

Other monomers In the present invention, in addition to the above-mentioned essential monomers, a monomer having an unsaturated ethylene bond copolymerizable therewith can be used if necessary. Examples include styrene, acrylonitrile, vinyl acetate and the like. These can be used in a proportion of 1 to 70% by weight based on the total amount of monomers. In addition, methyl (meth) acrylate ethyl (meth)
Acrylate, n-propyl (meth) acrylate, i
The (meth) acrylate having an alkyl group having 3 or less carbon atoms, such as so-propyl (meth) acrylate, is also within a range that does not adversely affect the physical properties of the obtained coating film, specifically, for all monomers, It can be used in a proportion of 0.1 to 28% by weight.

Glass transition temperature The polymer used in the present invention is a polymer having a glass transition point (hereinafter referred to as Tg point) of −20 ° C. or lower among the polymers obtained by polymerizing the above monomers. Those having a Tg point of more than -20 ° C. are not preferable because the cracking of the base is poor, the following properties are poor, the adhesiveness is lowered, and in many cases, the water resistance is poor. The Tg point of the polymer used in the present invention is a temperature at which various properties of the amorphous polymer suddenly change, and below this temperature, the molecular segment motion of the amorphous portion of the polymer is frozen. To actually measure the Tg point of a polymer,
As an example, a method is generally used in which the thermal expansions at various temperatures are measured, the specific volumes are plotted against the respective temperatures, and the temperature at the bending point in the obtained curve is determined. However, since the value of the Tg point of a polymer composed of individual homo-monomers is known in practice, the Tg value of the copolymer is
The value of the point can be obtained by the following calculation formula.

[0010]

[Formula 1]

CA: weight fraction of component A CB; weight fraction of component B TgA; Tg point of component A homopolymer (absolute temperature) TgB; Tg point of component B homopolymer (absolute temperature) where CA + CB = 1.

The main polymers having a Tg point of -20 ° C or lower (Tg point in parentheses) are polyethyl acrylate (-
22 ° C, poly-n-butyl acrylate (-54
C), poly-2-ethylhexyl acrylate (-85
C.), etc., and a polymer having a Tg point of -20.degree. ), Polymethacrylic acid (130 ℃)
Etc. (For the Tg points of polymers other than these, see the Chemical Handbook, etc., published by Maruzen Co., Ltd.). As an example of calculating the Tg point of the copolymer, the Tg point of the copolymer of 70 parts by weight of butyl acrylate and 30 parts by weight of styrene is −23 ° C. when calculated from the equation (1).

Emulsion The emulsion used in the present invention can be easily obtained by polymerizing the above-mentioned monomer in water in the presence of the following cationic or nonionic surfactant by a conventional method, and is usually obtained. The solid content concentration of the emulsion is 30 to 70% by weight. Further, the pH value of this emulsion is preferably 7 to 10 from the viewpoint of stability, and the pH value of the emulsion should be adjusted using ammonia, water-soluble amine, sodium hydroxide, potassium hydroxide or the like. Is preferred. However, as long as the emulsion has good stability even in a weakly acidic or acidic region, it can be sufficiently used as it is for the purpose of the present invention. The emulsion used in the present invention may contain an antifoaming agent as another component. As the defoaming agent, generally used defoaming agents such as octyl alcohol, capryl alcohol, auryl alcohol and cyclohexanol can be used. The compounding ratio of the defoaming agent is 0.1 with respect to the polymer solid content.
-5% by weight is preferred.

Surfactant The surfactant used for producing the emulsion used in the present invention is selected from nonionic and cationic surfactants.
It can be used arbitrarily. Anionic surfactants reduce the water resistance of the coating film, and are therefore unsuitable for the use of the present invention in which water is constantly contacted. As the cationic surfactant that can be used in the present invention, various ones can be used, and specifically, trimethyl octadecyl ammonium chloride, trimethyl dodecyl ammonium chloride, trimethyl hexadecyl ammonium chloride, alkyldimethylbenzyl ammonium chloride, distearyl. Quaternary ammonium salts such as dimethylammonium chloride and trimethylstearyl ammonium chloride, dimethyloctylamine, dimethyldecylamine,
Dimethyllaurylamine, dimethylmyristylamine,
Dimethyl palmityl amine, dimethyl stearyl amine, dimethyl oleyl amine, trioctyl amine, N
-Methylmorpholine, dimethylbenzylamine, and tertiary amines such as polyoxyethylene alkylamine. As the nonionic surfactant that can be used in the present invention, any nonionic surfactant can be used as long as it is usually used in an acrylic emulsion. Specific examples include polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether, and other polyoxyethylene alkyl or alkylphenol ethers, sorbitan monostearate. , Sorbitan monolaurate, sorbitan distearate, sorbitan monooleate and sorbitan trioleate, sorbitan fatty acid esters, polyoxyethylene sorbitan monolaurate and other polyoxyethylene sorbitan fatty acid esters, polyethylene glycol fatty acid esters, and glycerin monofatty acid Esters and the like can be mentioned. Among these surfactants, it is preferable to use a polyethylene oxide nonionic surfactant having an HLB value of 15 or more, particularly from the viewpoint of good polymerization stability and mechanical and chemical stability. The content of the surfactant may vary depending on the properties required for the emulsion, but in order to improve the stability of the emulsion, it is preferable that the content of the surfactant is large, the drying property and the coating film. In order to improve the water resistance of, it is preferable that the compounding amount is small. A suitable blending amount range is 1 to 10% by weight based on the polymer solid content of the emulsion, and the blending amount may be determined according to the purpose.

○ Inorganic hydraulic substance The inorganic hydraulic substance used in the present invention makes the coating film of the obtained composition tough by adding it to the above emulsion, and also the water resistance of the coating film and the adhesion to the wet surface. And the dry film-forming property can be improved. Examples of the inorganic hydraulic material include various cements, anhydrous and hemihydrate gypsum, quicklime, zinc white, and the like. Of these, it is preferable to use cement, for example, ordinary Portland cement, alumina cement, early strength cement, fly ash cement, blast furnace cement, white cement, colloidal cement and moderate heat Portland cement, etc.,
Further, among these, Portland cement or alumina cement, which is particularly easily available and can sufficiently exhibit the effects of the present invention, is preferable. These inorganic hydraulic substances are, based on 100 parts by weight of the solid content of the emulsion,
It is preferable to add 10 to 300 parts by weight. If it is less than 10 parts by weight, the toughness of the coating film may be insufficient and the adhesion to the wet surface may be poor, which is not preferable. 300
If it exceeds the weight part, the flexibility of the coating film is not sufficient,
The cracking of the base may not be sufficient. Two or more kinds of inorganic hydraulic substances can be used in combination.

Other components It is also possible to add a general-purpose filler to the waterproof material composition of the present invention. When a filler is compounded, effects such as improvement of coating workability, imparting toughness to a coating film, and reduction of coating film tack may be observed. Specific examples of the filler include silica sand, talc, calcium carbonate, kaolin,
General-purpose materials such as gypsum and diatomaceous earth can be used. The compounding amount of the filler is preferably 20 to 600 parts by weight with respect to the cement in the composition. If it is less than 20 parts by weight, the compounding effect of the filler may not be particularly recognized. On the other hand, if it exceeds 600 parts by weight, the coating film of the waterproofing material composition may be cracked on the ground and the followability may be poor. Or, the composition may have a high viscosity, and the coating workability may deteriorate.

○ Method of applying waterproof material composition Next, a method of applying the waterproof material composition of the present invention will be described. The waterproofing material composition can be applied by a usual method, for example, it is applied to the surface of the structure to be waterproofed by a brush or a roller, or by a general method such as spraying with a spray gun. , Form a coating film. Although the viscosity of the waterproof material composition varies depending on the application method, it is 300 cps.
Above (B type viscometer, 12 revolutions, rotor No. 4, 20
(° C) is preferable because it is excellent in workability, and more preferably 1000 to 50,000 cps. Viscosity 3
If it is less than 00 cps, it becomes difficult to apply a thick coat at a time, and if it has a high viscosity, there is an advantage that a thick coat can be applied, but if the viscosity is too high, the workability tends to be difficult.

The amount of the waterproof material composition applied to the substrate is preferably adjusted so that the film thickness after film formation is 300 μm or more, more preferably 500 to 3000 μm.
m. If the film thickness is too thin, the underlying crack-cracking ability deteriorates and causes water leakage.On the other hand, if the film thickness is too thick, the underlying crack-following ability is improved and there is an advantage that cracks and cracks are less likely to occur. In some cases, the amount of the composition used increases and the corresponding effect cannot be obtained, and the inside of the coating film may become difficult to dry.

○ Substrate treatment In applying the waterproof material composition of the present invention, when the structure to be waterproofed has large voids in joints and gaps, a sealing material, mortar and resin emulsion are applied to these locations. It is preferable to fill the voids in advance with a cement mixture or the like mixed with, and then apply the waterproof material composition. It is also possible to apply the surface treatment material in advance to the body and then apply the waterproof material. Examples of the base treatment material include epoxy resin emulsions and other general commercially available emulsions, solvent type paints, and adhesives. However, when the undercoating material is used, it is preferable to select the undercoating material with sufficient consideration so as not to impair the adhesiveness in a wet state.

O Topcoat Material The waterproof material composition of the present invention may be applied with a topcoat material for the purpose of improving aesthetics. Examples of the overcoat material include acrylic resins, acrylic urethane resins, acrylic silicone resins, fluororesins, and epoxy resins.

[0021]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. In the following, "part" means "part by weight" and "%" means "% by weight". ○ Example 1 (1) Production of emulsion In a stainless steel reaction kettle equipped with a stirrer having an internal volume of 20 liters, 103.5 parts of ion-exchanged water was put, and the internal temperature was adjusted to 80.
After heating to ℃, 2-ethylhexyl acrylate 37
Parts, n-butyl acrylate 37 parts, methyl acrylate 1 part, styrene 23 parts, glycidyl methacrylate 1 part, acrylic acid 1 part, azobisaminopropane hydrochloride 0.5 part and polyoxyethylene nonyl phenyl ether (HLB18.5). ) A mixed solution consisting of 3 parts was continuously added dropwise with stirring, while 1 part of 2,2'-azobis-2-aminodipropane as a polymerization catalyst was added dropwise continuously with stirring to carry out a polymerization reaction. After 6 hours, the polymerization reaction was completed,
An emulsion having a solid content concentration of 50% was obtained. Emulsion No. 1

(2) Production of waterproof material composition 100 parts by weight of the emulsion No. obtained in the preceding paragraph. A waterproof material composition was obtained by mixing 50 parts by weight of alumina cement with 1.

(3) Preparation of test piece A slate plate (30 × 30 × 0.5 cm) was coated with the waterproofing material composition prepared in the preceding paragraph by an air spray gun at 2.0 kg /
m ² spraying, 20 ° C., 60% R.M. H. It was left for 7 days under the conditions to obtain a test specimen for evaluation.

(4) Wet adhesion test The prepared test piece was completely submerged in water at 20 ° C, left for 1 week and then taken out from the water, and the adhesiveness was evaluated by peeling by hand (peeling test). ． H. After leaving it in the air for 1 day, the adhesive strength was measured by a Kenken-type adhesive strength tester, and the breaking point was recorded. The measurement results are shown in Table 2. This waterproof material composition has good adhesiveness by a peeling test,
The adhesive strength was as large as 12 kgf / cm ^2, and the peeling point was also the destruction of the waterproof material base material, and the adhesive strength in the wet state was good.

(5) Crack-following follow-up test of the underlayer A cut-out was made on the slate surface of the manufactured test piece which was not coated with the waterproof material composition, and the crack-following test piece shown in FIG. 1 was processed. This test piece is 5 m in the direction of the arrow in FIG.
A tensile test was carried out at a tensile speed of m / min to measure the following crack width when a pinhole or breakage occurred in the waterproof material.
The measurement results are shown in Table 2. This waterproof material composition had an excellent crack-following property of 4 mm.

(6) Evaluation of coating film tack The coating film of the test sample was evaluated by touch with the fingers to evaluate the tack of the coating film. The evaluation results are shown in Table 2. In Table 2, ○, △,
X has the following meaning. ◯: No tack is felt on the coating film Δ: Some tackiness of the coating film is felt x: Strong tackiness of the coating film This waterproofing material composition was good with almost no feeling of tackiness of the coating film.

[0027]

[Table 1]

[0028]

[Table 2]

Examples 2 to 5 Emulsion No. 2 was prepared in the same manner as in Example 1 except that the monomers, emulsifiers and catalysts shown in Table 1 were used. 2-4 were produced. Emulsion No. Example 1 using 1-4
A waterproofing material composition having the composition shown in Table 2 was produced in the same manner as in. A coating film was evaluated on the obtained waterproofing material composition in the same manner as in Example 1. The results are shown in Table 2. All of these waterproofing material compositions were produced according to the present invention and showed good performances in wet adhesion, crack followability and coating tack. Example 2 is a mixture of the waterproof material composition of Example 1 and a filler. The coating exhibits excellent performance with or without fillers. Example 3 is different from Example 1 mainly in the monomer composition of the acrylic emulsion, and is a combination of some fillers. Within the scope of the present invention, the coating film had excellent performance when the amount of the essential constituent monomer used was changed. Example 4 uses Portland cement instead of alumina cement. Within the range of the present invention, the coating film had excellent performance even if the type of cement was changed. Example 5 is a case where an acrylic emulsion in which a nonionic emulsifier and a cationic emulsifier were used in combination was used, and like the above Examples, the coating film had excellent performance.

Comparative Example 1 Emulsion No. 1 was prepared in the same manner as in Example 1 except that the monomers, emulsifiers and catalysts shown in Table 1 were used. Manufacture 5,
Using this, a waterproofing material composition having the composition shown in Table 2 was produced in the same manner as in Example 1. A coating film was evaluated on the obtained waterproofing material composition in the same manner as in Example 1. The results are shown in Table 2. This waterproof material composition had a high Tg point of the polymer of 29.9 ° C., and according to the test results, the crack followability was as small as 0.6 mm, and the performance as a waterproof material was not sufficient. .

Comparative Example 2 Emulsion No. 1 was prepared in the same manner as in Example 1 except that the monomers, emulsifiers and catalysts shown in Table 1 were used. Manufactured 6,
Using this, a waterproofing material composition having the composition shown in Table 2 was produced in the same manner as in Example 1. A coating film was evaluated on the obtained waterproofing material composition in the same manner as in Example 1. The results are shown in Table 2. This waterproofing material composition uses a polymer produced without using glycidyl methacrylate as a monomer, and according to the test results, the adhesive strength is low, and the coating film tack is strong, so that Was not suitable as a waterproof material for

Comparative Example 3 Emulsion No. 1 was prepared in the same manner as in Example 1 except that the monomers, emulsifiers and catalysts shown in Table 1 were used. 7 produced,
Using this, a waterproofing material composition having the composition shown in Table 2 was produced in the same manner as in Example 1. A coating film was evaluated on the obtained waterproofing material composition in the same manner as in Example 1. The results are shown in Table 2. This waterproofing material composition uses a polymer produced without using (meth) acrylic acid. According to the test results, the adhesive strength is low, and the tackiness of the coating film is strong. It was unsuitable as a waterproof material.

Comparative Example 4 Emulsion No. 1 was used to produce a waterproof material composition having the composition shown in Table 2 in the same manner as in Example 1. A coating film was evaluated on the obtained waterproofing material composition in the same manner as in Example 1. The results are shown in Table 2. This waterproofing material composition does not use an inorganic hydraulic substance, and according to the test results, the adhesive strength is low, and the interface peeling with the base material slate occurs, and the coating film tack is From a strong point, it was unsuitable as a waterproof material for this application.

[0034]

INDUSTRIAL APPLICABILITY The waterproof material composition of the present invention is particularly suitable for the inner surface waterproofing of water tanks for water and sewage systems, and since the waterproof material is water-based, it can be worked with peace of mind even in a sealed place.
Further, the obtained coating film is excellent in water resistance, crack-following property and adhesiveness under wet conditions, and can form a highly reliable waterproof layer.

[Brief description of drawings]

FIG. 1 is a diagram showing a test body used in a base crack followability test in Examples and Comparative Examples, (a) is a top view, and (b) is a side view.

[Explanation of symbols]

 Coating film of 1 waterproofing material composition

Claims (2)

[Claims] 1. At least one monomer selected from alkyl (meth) acrylates having an alkyl group having 4 to 10 carbon atoms in an amount of 30 to 98% by weight, (meth) acrylic acid in an amount of 0.1 to 3% by weight, and Glycidyl (meth) acrylate 0.1 to 5% by weight is used as an essential constituent monomer, and the glass transition temperature is -2.
A waterproof material composition comprising an emulsion in which a polymer having a temperature of 0 ° C. or lower is emulsified and dispersed in water by a cationic or nonionic surfactant, and an inorganic hydraulic substance. 2. 30 to 98% by weight of one or more monomers selected from alkyl (meth) acrylates having an alkyl group having 4 to 10 carbon atoms, 0.1 to 3% by weight of (meth) acrylic acid, and Glycidyl (meth) acrylate 0.1 to 5% by weight is used as an essential constituent monomer, and the glass transition temperature is -2.
A water tank waterproof material composition comprising an emulsion in which a polymer having a temperature of 0 ° C. or lower is emulsified and dispersed in water by a cationic or nonionic surfactant, and an inorganic hydraulic substance.