JPH09177259A - Coating waterproof technique - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish a technique of forming waterproof layers in a multilayer inclined structure. SOLUTION: A coating waterproof technique of forming a plural of waterproof layers on a substrate is to form individual water proof layers with coating waterproof composition and set the elongation percentage of a lower side waterproof layer greater than that of an upper side water proof layer in composition for the individual layers to be formed. For the coating waterproof composition, (a) one or more type of monomer selected out of alkyl(metha)acrylate with 4-10 carbon number alkyl groups, (b) (metha)acrylic acid and (c) glycidyl(metha) acrylate are essentially constitutional monomers and emulsion which is obtained by emulsifying and dispersing polymer with a glass transition temperature of -20 deg.C or less into water with specified surface active agent, non-organic hydraulic material and filler are contained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating film waterproofing method for forming a waterproof layer having a multi-layered inclined structure on a base, such as a roof, an eaves, a balcony, a veranda, a kitchen, a bathroom, and a washbasin of a building. It is useful as a waterproofing method for double walls and floors of toilets, toilets, basements, various water tanks, around sashes, double floors, etc., and can be widely used in the field of civil engineering and construction.

[0002]

2. Description of the Related Art Waterproofing methods applied to buildings are roughly classified into asphalt waterproofing methods, sheet waterproofing methods, coating film waterproofing methods and the like. Among these waterproofing methods, the asphalt waterproofing method has high reliability in waterproofing, but it requires a heat source for construction, which adversely affects workers and the environment. Although it has the drawbacks such as the required construction technology, and the fact that the waterproof layer is thick and its own weight is heavy, it is useful for waterproofing large floors on the roof and indoors, but it does not cover the details of the building. Is difficult to cover. Although the sheet waterproofing method is relatively easy to install, it is not possible to obtain a seamless waterproof surface, and it is difficult to apply to parts with complicated shapes such as small area parts and entrance / exit corners, and it is due to the joint part. It has drawbacks such as many failures. The coating film waterproofing method is currently used for waterproofing various buildings as a method of improving the problems of the above waterproofing method. However, among these coating film waterproofing methods, the method using urethane resin is excellent in workability due to self-leveling of the resin used,
Although it can be applied as a thick film and the coating film is excellent in toughness and finish, it has insufficient durability such as weather resistance and hot water resistance. On the other hand, the waterproofing method using an aqueous emulsion called a hydrated coagulation type waterproofing material is roughly classified into a method using an ethylene vinyl acetate emulsion and an acrylic emulsion, but in a method using an ethylene vinyl acetate emulsion, Although it has features such as self-closing property, due to this, water resistance, alkali resistance, hot water resistance, etc. are not sufficient. On the other hand, the method using an acrylic emulsion is excellent in weather resistance, hot water resistance, water resistance and alkali resistance, and the acrylic rubber emulsion type is particularly excellent in elasticity and durability.

However, the coating film waterproofing method using an acrylic emulsion is excellent in the ability to follow cracks in the base, but the coating film has tack when an emulsion for forming a coating film having a large elongation is used. In addition, it has a problem that it is inferior in external damage resistance. On the other hand, in order to improve the tack and scratch resistance of the coating film, when using an emulsion that forms a coating film having a low elongation, it is possible to increase the tack and scratch resistance of the coating film, but The crack followability was not sufficient, and the coating film sometimes broke due to the crack. As a waterproofing method for solving these problems, a so-called composite film is formed by forming a coating film having a small shear elastic modulus as a lower waterproofing layer on the base, and further forming a waterproof layer having a large shearing elastic modulus on this coating film. A construction method for forming a waterproof layer having a layer-gradient structure has been proposed (JP-A-7-11744).

[0004]

However, in the method for forming the waterproof layer having the multi-layered gradient structure, depending on the kind of the coating film waterproofing composition, particularly the kind of the polymer as the constituent component, it is difficult to follow the cracking of the base. There are cases where it is excellent and cases where it is not, and cases where the toughness and trauma resistance of the coating film are sufficient and cases where it is not so, and it is said that it is well established as a coating film waterproofing method. It was something I couldn't say.
The inventors of the present invention have made earnest studies to establish a method for forming the waterproof layer having the multi-layered inclined structure.

[0005]

The inventors of the present invention have used a composition comprising a specific acrylic polymer emulsion, an inorganic hydraulic material and a filler in the method for forming the waterproof layer having the multilayered gradient structure. Then, the composition is applied to a base to form a waterproof layer having a large elongation rate, and then a composition for forming a waterproof layer having a smaller elongation rate than the waterproof layer is applied and laminated on the waterproof layer. The inventors have completed the present invention by finding that the obtained waterproof layer is excellent in underlay crack followability, toughness and scratch resistance. In this specification, acrylate and / or methacrylate is referred to as (meth) acrylate, and acrylic acid and / or methacrylic acid is referred to as (meth) acrylic acid. Hereinafter, the present invention will be described in detail.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

◎ Coating Water-Proofing Composition ○ Emulsion The emulsion constituting the coating film waterproofing composition used in the present invention is one kind selected from (a) an alkyl (meth) acrylate having an alkyl group having 4 to 10 carbon atoms. A polymer obtained by emulsifying and dispersing the above-mentioned monomer, a polymer having (b) (meth) acrylic acid and (c) glycidyl (meth) acrylate as essential constituent monomers in water with a surfactant. The components of will be described.

(A) Alkyl (meth) acrylate having an alkyl group having 4 to 10 carbon atoms Specific examples of the alkyl (meth) acrylate having an alkyl group having 4 to 10 carbon atoms in the present invention include n-butyl (meth). ) Acrylate, iso-butyl (meth) acrylate, sec-butyl (meth) acrylate, n
-Amyl (meth) acrylate, iso-amyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, oxoheptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl ( (Meth) acrylate, n
-Nonyl (meth) acrylate, Oxononyl (meth)
Examples thereof include acrylate, n-decyl (meth) acrylate and oxodecyl (meth) acrylate. 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 lowered. The proportion of the above-mentioned monomer in the total monomers including the desired monomer is 30 to 98% by weight, and more preferably 40 to
90% by weight. If this ratio is less than 30% by weight, the coating film will be inferior in crack resistance to ground cracks, water resistance and alkali resistance. On the other hand, if it exceeds 98% by weight, not only tackiness will occur in the coating film, but also sufficient coating strength will be obtained. Can't get

(B) (Meth) acrylic acid The (meth) acrylic acid used in the present invention acts as a crosslinking component with glycidyl (meth) acrylate which is another essential constituent monomer component in the polymer, and also an emulsion. When an inorganic hydraulic material is mixed with an inorganic hydraulic material, it forms internal crosslinks between the carboxyl groups and polyvalent metal ions such as calcium ions in the inorganic hydraulic material, imparts toughness to the coating film, and further kneading stability It also functions as a dispersant that imparts Their proportion in all monomers ranges from 0.1 to 3% by weight. If this proportion is less than 0.1% by weight, the adhesiveness will decrease, and the toughness and external damage resistance of the resulting coating film will decrease, or tack will occur. On the other hand, if it exceeds 3% by weight, 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.

(C) 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 is used in an arbitrary range of 0.1 to 5% by weight in all monomers, but preferably 0.1 to 3% by weight in terms of polymerization operation. Is preferred. When the content of glycidyl (meth) acrylate is less than 0.1% by weight, the adhesiveness is decreased, the toughness and external damage resistance of the obtained coating film are decreased, and tack is generated. If it is used in excess of%, not only the toughness of the coating film is too great, but also agglomerates tend to occur during the polymerization operation, which is not preferable.

(D) Other Monomers In the polymer used in the present invention, in addition to the above-mentioned essential monomers, a monomer having an unsaturated ethylene bond copolymerizable with them is added to the polymer. It can be used as a desired monomer for controlling the physical properties, if necessary, and specific examples thereof include styrene, acrylonitrile, vinyl acetate and the like. These are 1 to 70% by weight with respect to the total monomers.
It is preferable that Further, it has an alkyl group having 3 or less carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and iso-propyl (meth) acrylate (meth).
Acrylate can also be used as a desired monomer, but it is preferably within a range that does not adversely affect the physical properties of the obtained coating film, specifically 0.1 to 28% by weight based on all monomers. . Further, in order to impart toughness to the waterproof coating film, N-methylol acrylamide, N-butoxymethyl acrylamide or the like can be appropriately used as a crosslinking component in the polymer.

(E) Glass Transition Temperature The polymer used in the present invention is a polymer having a glass transition temperature (hereinafter referred to as Tg) of −20 ° C. or lower obtained by polymerizing the above monomers. Those having a Tg of more than -20 ° C are not preferable because they are inferior in the ability to follow the underlying cracks, the adhesiveness is lowered, and in many cases, the water resistance is poor. The Tg of a polymer is the temperature at which various properties of the amorphous polymer change suddenly.
Below this temperature, the temperature is such that the molecular segment motion of the amorphous portion of the polymer is frozen, or from the Tg already known for the homopolymers of the individual homomonomers that make up the polymer, It is calculated by a calculation formula.

[0012]

(Equation 1)

CA: Weight fraction of monomer A in the polymer CB: Weight fraction of monomer B in the polymer ... CN: Weight fraction of monomer N in the polymer TgA; Monomer A Tg (absolute temperature) of homopolymer TgB; Tg (absolute temperature) of monomer B homopolymer ... TgN; Tg absolute temperature of monomer N homopolymer) where CA + CB + ... + CN = 1 Is.

The main examples of homopolymers having Tg of -20 ° C or lower (Tg in parentheses) are polyethyl acrylate (-22 ° C) and poly-n-butyl acrylate (-54).
C), poly-2-ethylhexyl acrylate (-85
C.) and the like, and a polymer having a Tg of -20.degree. C. or less, which is composed of a monomer copolymerizable with these, polymethyl acrylate (8.degree. C.), polystyrene (87.degree. C.), polyvinyl acetate (30.degree. , Polymethylmethacrylate (130
℃) etc. (For the Tg of polymers other than these,
See the Chemical Handbook issued by Maruzen Co., Ltd.). Copolymer Tg
The Tg of the copolymer of 70 parts by weight of butyl acrylate and 30 parts by weight of styrene can be calculated from the above formula as follows.
It becomes 23 ° C. As described above, the Tg of the polymer used for the emulsion in the method of the present invention is −20 ° C. or lower, and by using such a soft polymer, when it is thickly applied as a waterproof material, cracks, cracks, etc. are formed during film formation. Does not occur.

(F) Emulsion The emulsion used in the present invention can be easily obtained by polymerizing the above-mentioned monomer in water in the presence of a cationic or nonionic surfactant by a conventional method, and is usually obtained. It is performed so that the polymer solid content concentration of the obtained emulsion is 30 to 70% by weight. In addition, p of this emulsion
The H value is preferably 7 to 10 from the viewpoint of stability,
It is preferable to adjust the pH value of the emulsion using ammonia, a water-soluble amine, sodium hydroxide, potassium hydroxide or the like. However, even in a weakly acidic or acidic region, an emulsion having good stability can be sufficiently used as it is for the purpose of the present invention. Other components such as an antifoaming agent can be added to the emulsion used in the present invention. As the defoaming agent, generally used defoaming agents such as octyl alcohol, capryl alcohol, auryl alcohol and cyclohexanol can be used.
As the blending ratio of the defoaming agent, with respect to the polymer solid content,
0.1-5% by weight is preferred.

(G) Surfactant The surfactant used in the production of the emulsion used in the present invention can be arbitrarily selected from nonionic or cationic surfactants. Anionic surfactants reduce the water resistance of the coating and are therefore unsuitable for applications of the present invention that are constantly in contact with water. There are various cationic surfactants that can be used in the present invention, and specific examples include trimethyl octadecyl ammonium chloride, trimethyl dodecyl ammonium chloride, trimethyl hexadecyl ammonium chloride, alkyldimethylbenzyl ammonium chloride, distearyl dimethyl ammonium. Quaternary ammonium salts such as chloride and trimethylstearyl ammonium chloride, dimethyloctylamine, dimethyldecylamine,
Dimethyl lauryl amine, dimethyl myristyl amine,
Dimethyl palmitylamine, dimethylstearylamine, dimethyloleylamine, trioctylamine, N
-Tertiary amines such as methylmorpholine, dimethylbenzylamine and polyoxyethylene alkylamine. As the nonionic surfactant in the present invention, any nonionic surfactant can be used as long as it is used in a usual acrylic emulsion. To give a concrete example,
Polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether polyoxyethylene alkyl or alkylphenol ether, sorbitan monostearate, sorbitan monolaurate, Examples thereof include sorbitan fatty acid esters such as sorbitan distearate, sorbitan monooleate and sorbitan trioleate, polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyethylene glycol fatty acid esters and glycerin monofatty acid ester.
Among these surfactants, especially polymerization stability, mechanical
From the viewpoint of good chemical stability, it is preferable to use a polyethylene oxide nonionic surfactant having an HLB value of 15 or more. The amount of the surfactant may vary depending on the properties required for the emulsion, but in order to improve the stability of the emulsion, the amount of the surfactant is preferably large, and the drying property and the coating In order to improve the water resistance of the composition, it is preferable that the amount is small. A suitable blending amount may be determined in consideration of these balances,
With respect to the polymer in the emulsion, preferably 1-10
It is determined according to the purpose within the range of weight%.

◎ Inorganic hydraulic substance By mixing the inorganic hydraulic substance with the above-mentioned emulsion, the coating film obtained is made tough, and at the same time, the water resistance of the coating film, the adhesion to the wet surface and the dry film-forming property are improved. Let Examples of the inorganic hydraulic material include various cements, anhydrous and hemihydrate gypsum, quicklime, zinc white, and the like. Among these, cement is preferable, ordinary Portland cement, alumina cement, early strength cement, super early strength cement, moderate heat Portland cement, sulfate resistant Portland cement, fly ash cement, blast furnace cement,
There are white cement, silica cement, colloidal cement and special cement. Among these, ordinary Portland cement and alumina cement are preferable, and it is more preferable to use alumina cement because it is excellent in acid resistance, hot water resistance and the like. It is also possible to use two or more types of inorganic hydraulic substances in combination.

◎ Filler The composition used in the present invention comprises the above emulsion, the inorganic hydraulic substance and a filler. The filler has an aggregate as a main component, and it is preferable to use an aggregate composed of an aggregate and a thickener.

(A) Aggregate The aggregate is preferably used for the purpose of adjusting the viscosity and increasing the amount when the emulsion and the inorganic hydraulic substance are mixed. As aggregates, dry silica sand, silica stone powder, talc, calcium carbonate, kaolin, clay, gypsum, diatomaceous earth, silica fume, fly ash,
Mention may be made of pozzolanic materials such as blast furnace slag, natural and synthetic silica, and general-purpose fillers such as glass or organic resin beads and balloons. Among these, it is preferable to combine dry silica sand with other fillers because the denseness of the composition and the kneading viscosity can be optimized. Dry silica sand is a general term for quartz sand rich in silicic acid content, chemical composition, water absorption etc. differ depending on the production site, but as dry silica sand suitable for the present invention, low water absorption,
Those having a particle size of 48 to 500 mesh are preferred.
As the other filler, a combination of calcium carbonate and / or clay is preferable, and it is more preferable to use clay because the resulting coating film has excellent acid resistance and alkali resistance. The ratio of dry silica sand and other fillers is as follows: dry silica sand: other fillers = 0.5:
It is preferably 9.5 to 9.5: 0.5 (weight ratio) and can be determined in consideration of physical properties and workability.

(B) Thickener A thickener is used for the purpose of imparting a thickening property and preventing sagging at the time of construction on a rising surface when the emulsion, the inorganic hydraulic substance and the aggregate are mixed. Is preferably used. As the thickener, general ones called thickener, anti-sagging agent, thixotropic agent and the like can be used, and it is preferable to use a fiber material. Specific examples of the fiber material include inorganic fibers other than asbestos such as basic magnesium sulfate, sepiolite (crystalline magnesium silicate clay mineral) and zonolite (crystalline calcium silicate), and of these, sepiolite is preferable. The sepiolite fiber is a specially processed natural fibrous clay mineral containing hydrous magnesium silicate as a main component, and preferably has a fiber length of 5 to 50 μm and a fiber diameter of 0.2 μm or less. Examples of other thickeners include inorganic thickeners such as silica and bentonite, water-soluble cellulose compounds such as ethyl cellulose, methyl cellulose and hydroxyethyl cellulose, natural organic thickeners such as polysaccharides and xanthan gum, and polyvinyl alcohol. Examples thereof include polyvinyl compounds such as, acrylic compounds such as sodium polyacrylate, and synthetic organic thickeners such as polyethylene oxide. It is also possible to use two or more thickeners in combination. The mixing ratio of the thickener is preferably 8 parts by weight or less with respect to the total amount of the inorganic hydraulic substance and the aggregate in order to improve the coating work.

(C) Other Compounds Other than the aggregate and thickener used in the present invention, other fillers include a fluidizing agent, a water reducing agent and a high-performance water reducing agent for the purpose of water reduction and flow adjustment. Etc., delaying agent for cement such as citric acid, sodium citrate, gluconic acid and boric acid for the purpose of delaying pot life, hardening of cement such as calcium chloride and aluminate for promoting hardening, etc. Accelerators, reinforcing short fibers such as carbon fibers and polypropylene fibers can be used within a range that does not impair the workability and the performance of the resulting coating film.

(D) Ratio of inorganic hydraulic substance to filler As the ratio of the inorganic hydraulic substance to the filler, the filler is 50 to 60 relative to 100 parts by weight of the inorganic hydraulic substance.
The ratio of 0 parts by weight is preferable, and more preferably 200.
５００500 parts by weight. If this ratio is less than 50 parts by weight, the inorganic hydraulic substance becomes excessive, so the flexibility of the coating film may be impaired, while if it exceeds 600 parts by weight, the toughness of the coating film becomes insufficient. There is.

Production of Coating Film Waterproofing Composition The coating film waterproofing composition used in the present invention can be obtained by mixing the above-mentioned emulsion, inorganic hydraulic substance and filler according to a conventional method. In this case, as the composition for forming the lower waterproof layer and the upper waterproof layer, the composition for forming the lower waterproof layer is 100 parts by weight of the total amount of the inorganic hydraulic substance and the filler. 30 ~ polymer
300 parts by weight, more preferably 40 to 200 parts by weight, is used, and the composition for forming the upper waterproof layer is a polymer based on 100 parts by weight of the total amount of the inorganic hydraulic material and the filler. Of 10 to 200 parts by weight, more preferably 15 to 150 parts by weight, and the amount of polymer in the composition for forming the upper waterproof layer is smaller than that in the lower waterproof layer. Is preferred. When the proportion of the polymer in the composition for forming the lower waterproof layer is less than 30 parts by weight, the flexibility of the coating film becomes insufficient,
On the other hand, if it exceeds 300 parts by weight, the toughness of the coating film becomes insufficient. Further, if the proportion of the polymer in the composition for forming the upper waterproof layer is less than 10 parts by weight, the ability to follow the deformation may be significantly impaired, while if it exceeds 200 parts by weight, tack may occur, A reduction in tilt effect may be seen.

◎ Coating film waterproofing method The coating film waterproofing method of the present invention is a method of forming a plurality of waterproof layers on a base using the above coating film waterproofing composition. In this case, the composition used As a configuration, the elongation rate of the obtained lower waterproof layer is larger than that of the upper waterproof layer,
A so-called multilayer inclined structure is formed on the coating film.
By forming such a waterproof layer, it becomes possible to impart a higher degree of crack followability to the waterproof layer.
In the present invention, the elongation percentages of the lower waterproof layer and the upper waterproof layer are values measured according to JIS A6021 (tensile test specified for roof waterproof film) at the same film thickness. As for the elongation rate of the lower waterproof layer to the upper waterproof layer, the greater the elongation rate of the lower waterproof layer, the better. However, the difference in the elongation rate between the lower waterproof layer and the upper waterproof layer is preferably 50% or more. Is preferred. The elongation rate of the lower waterproof layer and the upper waterproof layer is
The polymer, which is a constituent of the coating film waterproofing composition, in the inorganic hydraulic substance and the filler, may be appropriately adjusted depending on the respective types and blending ratios, but is adjusted by the blending ratio of the polymer to the inorganic hydraulic substance and the filler. Preferably.

[Substrate] The type of substrate targeted by the present invention is not particularly limited, and it can be applied to all building materials such as slate, metal, glass and plastic including cement concrete and mortar. In this case, it is preferable to apply a surface treatment agent, an undercoat material shown below, or the like in advance in order to strengthen the adhesion to the base.
In applying the composition, the surface irregularities, gaps, and defects of the base material to be waterproofed are treated with a sealing material, polymer cement mortar, epoxy resin putty, the composition used in the present invention, etc. to smooth the base surface. Is preferred.

○ Coating method As a coating method of the composition, a usual method may be adopted, for example, a brush, a wool roller, a mastic roller, a trowel or a rake, or an airless coating is applied to the substrate. Alternatively, a method of spraying with an air spray or the like can be mentioned.

Although the viscosity of the composition varies depending on the coating method, it is preferable to use 300 cps or more (B-type viscometer, 12 revolutions, rotor No. 4, measurement at 20 ° C.) in terms of workability, and more preferable. Is 1,000 to 50,0
It is 00 cps. If the viscosity is less than 300 cps,
It may be difficult to apply a thick coat at a time, and if the viscosity is high, the workability may be impaired. At the construction site, if the viscosity of the composition used is higher than the specified viscosity,
It is also possible to adjust the viscosity by diluting with water.

When forming the waterproof layer, it is possible to reinforce with a cloth or mesh of polyester, glass or the like. The waterproof layer is laid on the ground surface or at the interface between the lower waterproof layer and the upper waterproof layer and cracked. The followability and the resistance to fatigue and the like can be enhanced.

○ Film thickness The film thickness of the lower waterproof layer and the upper waterproof layer is 300 μm.
It is preferably not less than 500, more preferably 500 to
It is 3,000 μm. If this thickness is less than 300 μm, the ability to follow the underlying cracks may deteriorate and the original function of the coating may be impaired. On the other hand, if this value is too large, the ability to follow the underlying cracks will improve, but the drying property Etc. The thickness of each of the lower waterproof layer and the upper waterproof layer may be arbitrarily determined according to the substrate to be applied, the purpose, etc., but it is more advanced to form the lower waterproof layer thicker than the upper waterproof layer. It is preferable because the crack followability can be obtained.

Undercoating material In the present invention, it is preferable to apply an undercoating material (primer) to the undercoat in order to improve the adhesiveness and the adhesion durability between the composition used and the undercoat. The undercoating material can be selected according to the type of base and the location of use, and a solvent-based or water-based epoxy resin primer, a rust preventive primer, or the like can be used.

Topcoat Material In the present invention, a topcoat material can be applied on the waterproof layer for the purpose of improving the appearance and protecting the appearance. As the topcoat material, water-based, solvent-based and solvent-free acrylic resins, acrylic urethane resins, acrylic silicone resins, fluororesins, epoxy resins and the like can be used. It is also possible to top coat cement mortar, polymer cement mortar or cement concrete for the purpose of pressing. When pouring cement concrete,
A sheet material is preferably used for the purpose of preventing damage to the waterproof material.

[0032]

The present invention will be described more specifically below with reference to examples and comparative examples. In addition, "part" in each example means "part by weight". ◎ Manufacture of coating film waterproofing composition ○ Manufacture of emulsion (1) Manufacture of emulsion A 103.5 parts of ion-exchanged water was put into a reaction vessel made of stainless steel equipped with a stirrer with an internal volume of 20 liters and the internal temperature was set to 80.
After heating to 2 ° C., 2-ethylhexyl acrylate 37
Parts, n-butyl acrylate 37 parts, acrylic acid 1 part,
A mixed solution consisting of 1 part of glycidyl methacrylate, 24 parts of styrene, 0.5 part of azobisaminopropane hydrochloride and 3 parts of polyoxyethylene nonylphenyl ether (HLB18.5) was continuously added dropwise under stirring, while so,
As a polymerization catalyst, 1 part of 2,2′-azobis-2-aminodipropane was continuously added dropwise under stirring to carry out a polymerization reaction. When the polymerization reaction was completed after 7 hours, an emulsion containing a polymer having a solid content concentration of 50% by weight was obtained. The Tg of the obtained polymer was -44.1 ° C. This is Emulsion A.

(2) Production of emulsion B As a monomer, 2-ethylhexyl acrylate 73
Parts, 1 part of acrylic acid, 1 part of glycidyl methacrylate and 25 parts of methyl methacrylate were polymerized in the same manner as in Example 1 to obtain an emulsion containing a polymer having a solid content concentration of 50% by weight. T of the obtained polymer
The g was -56.0 ° C. This is called emulsion B.

(3) Production of emulsion C 23 parts of 2-ethylhexyl acrylate as a monomer,
Polymerization was performed in the same manner as in Example 1 except that 1 part of acrylic acid, 1 part of glycidyl methacrylate and 75 parts of styrene were used to obtain an emulsion containing a polymer having a solid content concentration of 50% by weight. The Tg of the obtained polymer was 29.9 ° C. This is called emulsion C.

(4) Preparation of emulsion D 37 parts of 2-ethylhexyl acrylate as a monomer,
Polymerization was performed in the same manner as in Example 1 except that 37 parts of n-butyl acrylate and 26 parts of styrene were used to obtain an emulsion containing a polymer having a solid content concentration of 50% by weight.
The Tg of the obtained polymer was -44.1 ° C. This is called emulsion D.

(5) Emulsion E An ethylene vinyl acetate emulsion (solid content 53%, Tg-20 ° C) dispersed with a commercially available nonionic surfactant was used. This is called emulsion E.

Production of Coating Film Waterproofing Composition The emulsions of the types and amounts shown in Tables 1 and 2, the inorganic hydraulic material and the filler were stirred and mixed to obtain a coating film waterproofing composition. With respect to each of the obtained compositions, the ability to follow cracks in the underlayer was measured by the following method. Also JISA
According to 6021, tensile strength and elongation were measured. The results are shown in Tables 1 and 2.

◎ Evaluation ○ Underground crack followability test Slate plate (70 × 150 × 4 mm, notched on the back surface)
The composition for waterproofing the coating film thus obtained was sprayed on the coated film so that the dry thickness was 1 mm, and the composition was dried at 20 ° C. and 60% R.A. H. The sample was dried and cured for 7 days under the conditions described above to prepare a test sample. About the obtained test body, the slate was split along the notches of the lateral method (not reaching the waterproof coating film), and a tensile test was performed at a pulling speed of 5 mm per minute in the longitudinal direction at 20 ° C. The crack width when a pinhole or the like was generated in the film was measured and taken as the crack followability.

○ Tensile test A polyvinyl chloride plate coated with a release agent was sprayed with the obtained coating film waterproofing composition so that the dry thickness was 1 mm, and the temperature was 20 ° C. and 60%.
R. H. The sample was dried and cured for 7 days under the conditions described above to prepare a test sample. After curing, peel off the coating film from the vinyl chloride board, punch out the dumbbell-shaped No. 3 shape, set the distance between the marked lines to 20 mm, and perform a tensile test at a pulling speed of 200 mm per minute at 20 ° C.,
The tensile strength and the elongation at break were measured from the maximum load when the coating film was broken and the distance between marked lines.

[0040]

[Table 1] 1) Unit is part.

[0041]

[Table 2] 1) Unit is part.

Example 1 A composition having a dry thickness of 0.7 mm was applied to a slate plate and a vinyl chloride plate coated with a release agent in the same manner as the above-described base crack followability test and tensile strength test. No. 1
After spraying and curing the composition in the same manner as described above, the composition No. was applied so that the dried thickness was 0.5 mm on the obtained coating film. 2 was sprayed and cured in the same manner as above to obtain a waterproof layer. The resulting waterproof layer was subjected to a base crack followability test and a tensile test in the same manner as above. Table 3 shows the results. By applying the elongation ratio of the lower waterproof layer to be larger than that of the upper waterproof layer, the following property of the base crack was excellent.

◎ Examples 2 to 4 By the same method as in Example 1, the coating film waterproofing composition shown in Table 3 was used to obtain the thickness shown in Table 3.
The obtained waterproof layer was subjected to a crack-underlying property following test and a tensile test in the same manner as in Example 1. Table 3 shows the results. In any of the examples in which the elongation of the lower waterproof layer was set to be larger than that of the upper waterproof layer, the crack followability was excellent.

[0044]

[Table 3]

Comparative Examples 1 to 3 By the same method as in Example 1, the coating film waterproofing composition shown in Table 4 was used to obtain the thickness shown in Table 4.
The obtained waterproof layer was subjected to a crack-underlying property following test and a tensile test in the same manner as in Example 1. The results are shown in Table 4. Comparative Example 1 In Comparative Example 1 constructed so that the elongation of the lower waterproof layer is smaller than that of the upper waterproof layer, the stress of the base cannot be relaxed, and the followability of the base crack is poor. The layered effect was not obtained. -Comparative Example 2 Even if the construction was performed such that the elongation rate of the lower waterproof layer was higher than that of the upper waterproof layer, the polymer used had a Tg of greater than -20 ° C, so that the underlying crack followability was high. It was poor. Comparative Example 3 Even if the lower waterproof layer is so constructed that its elongation rate is higher than that of the upper waterproof layer, (meth) acrylic acid and glycidyl (meth), which are essential constituent monomers of the polymer of the present invention, are used. )
In Comparative Example 3 in which a polymer lacking acrylate was used, although it was excellent in the ability to follow the underlying crack, the toughness of the coating film was poor and the surface was soft, and therefore the resistance to trauma was poor. -Comparative example 4 It was constructed such that the elongation rate of the lower waterproof layer was higher than that of the upper waterproof layer, and the Tg of the polymer used was -2.
Even at 0 ° C., when an ethylene vinyl acetate resin different from the polymer used in the present invention was used, the ability to follow the underlying crack was poor.

[0046]

[Table 4]

[0047]

According to the coating film waterproofing method of the present invention, since a water-based composition is used, it is safe for the installer, and the resulting waterproof layer has a base crack following property, toughness and external damage resistance. It is possible to provide a highly reliable waterproof layer which is excellent in heat resistance, adhesiveness, etc., and is useful as a waterproofing method for various buildings.

Front page continued (72) Inventor Tatsuyuki Hirano 4-1-1 Honmachi, Chuo-ku, Osaka City, Osaka Prefecture Takenaka Corporation, Osaka Main Store (72) Inventor Nobunao Murakami 1 Otsuka, Inzai-cho, Inba-gun, Chiba Prefecture Takechome Co., Ltd. Technical Research Institute

Claims (2)

[Claims] 1. A coating film waterproofing method for forming a plurality of waterproof layers on a substrate, wherein each waterproof layer is formed by the following coating film waterproofing composition, and a composition of the composition for forming each layer. Is a coating waterproof method in which the elongation of the lower waterproof layer is larger than that of the upper waterproof layer. Coating-preventing water composition: (a) 1 selected from alkyl (meth) acrylates having an alkyl group with 4 to 10 carbon atoms
One or more monomers, (b) (meth) acrylic acid and (c)
Glycidyl (meth) acrylate was used as an essential constituent monomer, and the proportion of each of the monomers was (a) 30-9.
8% by weight, (b) 0.1 to 3% by weight and (c) 0.1
A composition comprising 5% by weight of a polymer having a glass transition temperature of −20 ° C. or lower, which is emulsified and dispersed in water by a cationic or nonionic surfactant, an inorganic hydraulic substance and a filler. 2. The proportion of the polymer in the coating film waterproofing composition for forming the lower waterproof layer is 30 to 300 parts by weight based on 100 parts by weight of the total amount of the inorganic hydraulic material and the filler. The proportion of the polymer in the coating film waterproofing composition for forming the upper waterproof layer is 10 to 20 with respect to 100 parts by weight of the total amount of the inorganic hydraulic substance and the filler.
The coating film waterproofing method according to claim 1, wherein the amount is 0 parts by weight and is smaller than the ratio of the polymer in the composition for forming the lower waterproof layer.