JPS6127421B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a waterproof coating method for concrete buildings. Conventionally, there are waterproof coatings made of a water-based emulsion made by emulsifying asphalt as its main material, but after being applied to the concrete base, the coating takes a long time to dry due to the moisture content, especially in the concave areas of the concrete surface. Water tends to accumulate on painted surfaces and corners of buildings, making it take longer to dry. Normally, the thickness of the coating film needs to be at least 2 to 3 mm, but after application, the water on the surface evaporates quickly and a dry film tends to form on the surface, preventing the evaporation of internal water. It is necessary to apply a very thin layer of water and then wait for it to dry before applying it over and over again to obtain a waterproof coating of 2 to 3 mm or more, making the painting process difficult and inefficient. become a target. Furthermore, the asphalt waterproof coating layer obtained in this manner tends to soften, flow, etc. when the temperature rises. Therefore, in order to improve this, for example, it is possible to mix cement into this, but the stretchability becomes poor and cracks are likely to occur due to vibrations, shocks, etc., making it unsuitable as a waterproof coating film. The present invention eliminates the above-mentioned drawbacks of waterproof coating using conventional waterproof coating agents, and enables waterproof coating without the accumulation of water in areas corresponding to concave parts of concrete or corners of buildings as in the past. Even if it is applied more than 2 to 3 mm at a time, a dry film is not formed on the surface, so moisture evaporation from the inside is not prevented, and a rapidly curing hydraulic film is produced. The coating film provides a waterproof coating with excellent vibration resistance, impact resistance, weather resistance, etc. It is made of asphalt water-based emulsion, which is the main material, and has a cement mixture resistance. Cement and hydraulic urethane prepolymer are added to a certain rubber emulsion or synthetic resin emulsion, and the mixture is uniformly applied to the base surface directly or to the sheet surface coated on the base surface. shall be. Next, examples of the present invention will be described in detail. The asphalt aqueous emulsion that is resistant to cement mixing, which is the main material used in the waterproof coating of the present invention, maintains an emulsified state during uniform mixing without immediately gelling when cement is added to the emulsified asphalt. It has properties and can be produced by conventionally known methods. This aqueous asphalt emulsion is produced by blending asphalt and emulsifier water so that the asphalt content in the asphalt aqueous emulsion is 55 to 65%. If the asphalt content exceeds 65%, the cement mixing resistance will deteriorate, and if the asphalt content exceeds 55%, there will be too much moisture, making it difficult to form a good coating film. In order to obtain an asphalt aqueous emulsion that is resistant to cement mixing, a conventionally known emulsifier for asphalt aqueous emulsion for cement mixing can be used as an emulsifier. For example, polyoxyethylene alkyphenol-based nonionic emulsifiers, or alkyl quaternary ammonium-based or alkylimidazoline-based cationic emulsifiers are optimal because they have little change in viscosity due to changes in temperature, are stable, and have good workability. be. As the cement to be mixed in, ordinary Portland cement, early strength cement, ultra early strength cement, etc. are used. In order to obtain the maximum water absorption performance of cement, that is, to obtain a cured coating film by reacting with water and curing without stagnation of free water on the surface of the cured coating film, the amount of cement to be added is approximately the same as that of water. This is similar to the case of obtaining a cured molded product of a normal mixture of cement and water. The urethane prepolymer mixed into the asphalt aqueous emulsion is a polyalkylene glycol having an average molecular weight of 1,000 to 10,000 and having 2 to 3 terminal hydroxyl groups and an organic polyisocyanate compound.
Those obtained by reacting at an NCO/OH equivalent ratio of 2 to 8 are suitable. (For example, the product name "Hicel"
OH-1, manufactured by Toho Chemical Industry Co., Ltd., trade name "Polygrout W-1" manufactured by Dai-ichi Kogyo Yakuhin Co., Ltd.) The above-mentioned polyalkylene glycol is prepared by a known manufacturing method, and has two active hydroxyl groups. Compounds having ~3 such as propylene glycol di- and tripropylene glycol, butanediol,
It can be obtained by addition polymerizing ethylene oxide and other alkylene oxides having 3 or more carbon atoms, such as propylene oxide, butylene oxide, styrene oxide, etc., to ethylene glycol, glycerin, trimethylolpropane, castor oil, etc. Further, the organic polyisocyanate compound includes aromatic organic polyisocyanates such as toluene isocyanate, diphenylmethane isocyanate, naphthalene diisocyanate, and polymethylene polyphenyl isocyanate.
The NCH/OH equivalent ratio is preferably 2 to 8. This hydraulic polyurethane has a maximum water absorption capacity of approximately 10 times its weight, and when it absorbs water, it chemically reacts with a portion of the water to generate carbon dioxide gas, forming a closed-cell rubber-like or agar-like structure. It has the ability to form elastic solidified materials. Therefore, when putting the present invention into practice, the amount of water in the predetermined amount of asphalt aqueous emulsion is taken into account when preparing the mixture, and cement and hydraulic preform are added in amounts sufficient to absorb substantially all of the water. It is preferable to mix it with a polymer. In addition, if an aqueous emulsion of rubber or synthetic resin is used in addition to this asphalt aqueous emulsion, the total amount of water contained in these should be considered and the amount of cement and hydraulic prepolymer mixed should be increased accordingly. Of course. To explain with an actual blending example, 100 parts by weight of asphalt aqueous emulsion (40 parts by weight) made to contain about 40% water, 30 parts by weight of Portland cement and 1 part by weight of hydraulic urethane prepolymer. Add and mix well, then pour this onto the concrete surface to be constructed and apply it to a uniform thickness of 2 mm or more. In such a case, a good waterproof coating layer with no accumulation of free water on the surface can be obtained, and a cured waterproof coating film with elasticity can be obtained by leaving it as it is for only 2 to 3 hours. In this case, unlike the conventional method, no dry film is formed on the surface, and therefore moisture can be evaporated from the inside well, resulting in a well-uniform dry coating film. As seen in the above formulation, cement has the ability to absorb up to approximately 100% of its weight in water;
The addition of 30% by weight will absorb about 30% of the water content of the asphalt aqueous emulsion, while the addition of 1 part by weight of hydraulic urethane prepolymer will absorb about 10% of the water content of the asphalt aqueous emulsion. Excessive free water is not generated on the surface of the coating film, resulting in a good coating. The mixture having the above formulation is in the form of a slurry, which facilitates the application process. Of course, it is possible to increase the blending amount of the above-mentioned hydraulic additive or to change the blending ratio appropriately to obtain a mixture having suitable fluidity and viscosity. Furthermore, if rubber latex or synthetic resin emulsion is additionally blended, it goes without saying that the amount of cement and/or hydraulic urethane prepolymer added should be increased in consideration of the added water content; in this case, By adding the rubber or synthetic resin, it is possible to further improve the extensibility of the coating film, the adhesion to the concrete surface or the surface of the waterproof material base material, weather resistance, corrosion resistance, etc. Incidentally, a small amount of inorganic or organic fibers or mixed fibers thereof may be added to the above-mentioned composition. According to the inventor's test research, the coating film targeted by the present invention cannot be obtained even if a mixture of only cement or only prepolymer is applied to asphalt aqueous emulsion; It is necessary to use additives in combination, and to obtain a desirable coating film,
It has been found that there is a suitable range for the amount of each added. Next, the results of the comparative experiment are shown in the table below.

[Table] As is clear from the table above, when only cement was added, the cured coating film was brittle, had a low elongation rate, and failed in weather resistance, as shown by the numbers in Experiment No. 1 and No. 2. In addition, when only hydraulic urethane prepolymer was added, as shown in the values of Experiment No. 7 and No. 8, the coating film was cured poorly and could not be measured, or the water resistance was poor. , a coating film unsuitable as a waterproof coating is formed. On the other hand, when cement and hydraulic urethane prepolymer are used together as in the present invention, as shown by the numerical values of Experiment Nos. 3, 4, and 5, cement or hydraulic urethane prepolymer as described above An excellent waterproof coating film that passes the standards in terms of tensile strength, tear strength, elongation rate, water resistance, and weather resistance (ozone resistance), which cannot be obtained by using each separately, can be obtained. I know that it will happen. Experiment No. 6 is slightly inferior in water resistance, but passes in all other respects, so if a laminate layer is applied to the surface of another waterproof base material, its mechanical properties and weather resistance can be improved. . However, it is disadvantageous as a coating film directly on concrete surfaces. According to many experiments, a coating film with an elongation rate of 100% or less and a water absorption rate of 5% or less is preferable because it is strong and stable against vibrations and impacts of concrete structures, and has strong water resistance. 4 and 5, it has been found that an excellent waterproof coating film can be reliably obtained by blending 20 to 30 parts by weight of cement and 1 to 4 parts by weight of polyurethane prepolymer to 100 parts by weight of asphalt aqueous emulsion. Ivy. The waterproof coating of the present invention may also be formed with sheets such as organic or inorganic woven fabrics, nonwoven fabrics, felt sheets, asphalt waterproof sheets, etc. In this case, the above-mentioned three materials of the present method may be applied to the base surface. A waterproof coating agent consisting of a mixture or any ordinary asphalt waterproofing agent, etc. is applied, and the sheet material is laid and adhered before it completely hardens or dries, and the waterproof coating agent of this method is applied on top of that. A film layer may also be formed. In this way, according to the present invention, the asphalt water-based emulsion is used as the main material, and a mixture of cement and hydraulic urethane prepolymer is applied to the surface to be waterproofed. Even if applied to a thickness of 2 mm or more at a time, it dries easily and becomes a self-hardening coating in a short time, making it easy to apply. There are disadvantages such as the case where a hard urethane prepolymer alone is used, resulting in a hardened coating film, or even if a cured coating film is formed, the stretching ratio is extremely small and the weather resistance is rejected. It has the effect of being able to obtain an excellent hydraulic coating film without causing any phenomenon.

Claims (1)

[Scope of Claims] 1. Cement and water-curing urethane are added to the main material, an asphalt aqueous emulsion that is resistant to cement mixing, or to which is added a rubber emulsion or a synthetic resin emulsion that is resistant to cement mixing. A waterproof coating method characterized by adding a prepolymer and applying a uniform mixture to the base surface directly or to a sheet surface coated on the base surface. 2. Cement and hydraulic urethane prepolymer are added to the main material, an asphalt aqueous emulsion that is resistant to cement mixing, or to which is added a rubber emulsion or a synthetic resin emulsion that is resistant to cement mixing. Claim 1, characterized in that the mixture is added in an amount sufficient to absorb substantially all of the moisture, and a uniformly mixed mixture is applied directly to the base surface or to a sheet surface coated on the base surface. Waterproof coating method. 3. To the asphalt water-based emulsion that is resistant to cement mixing, which is the main material, or to which an emulsion that is resistant to cement mixing or a synthetic resin emulsion is added, based on 100 parts by weight of the emulsion that is resistant to cement mixing. , characterized in that 20 to 30 parts by weight of Portolan cement and 1 to 4 parts by weight of hydraulic urethane prepolymer are added and mixed uniformly and applied directly to the substrate surface or to the sheet surface coated on the substrate. The waterproof coating method according to claim 1.