Room temperature curing two-component coating composition, waterproofing agent and waterproofing method

Abstract

To provide a room temperature-curable two-pack coating composition which takes human bodies and the environment into consideration while achieving sufficient tensile strength, tear strength and tensile product generally required for a coating film waterproof material made of polyurethane after curing.SOLUTION: The room temperature-curable two-pack coating composition comprises a main agent containing a urethane prepolymer and a curing agent. The urethane prepolymer is a reaction product of a polyol and a polyisocyanate. The urethane prepolymer has a terminal isocyanate group derived from hydrogenated xylylene diisocyanate. The polyol contains polytetramethylene ether glycol, polyoxypropylene diol, and polyoxypropylene triol. An isocyanate concentration in the main agent is 0.9-1.90 mass%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a room temperature curing two-component coating composition, a waterproofing agent comprising this composition, and a waterproofing method using this waterproofing agent. [Background technology]

[0002] Urethane rubber-based waterproof coating materials can generally form a highly reliable waterproof layer regardless of whether the substrate is of a regular or irregular shape. Therefore, they are used for waterproofing verandas, balconies, open corridors, roofs, parapets, and platforms in apartment buildings, both in new construction and renovation work. They are also widely used in applications such as floor coatings and elastic paving for sports facilities.

[0003] Currently, the most commonly used hand-applied, two-component, room-temperature-curing urethane rubber-based waterproofing coating materials often use a urethane prepolymer containing toryl resin isocyanate (hereinafter also referred to as "TDI") and polyoxypropylene diol as the base agent, 3,3-dichloro-4,4'-diaminodiphenylamine (hereinafter also referred to as "MOCA") or diethyltoluenediamine (hereinafter also referred to as "DETDA") as the curing agent, and the phthalate diesters di-2-ethylhexyl phthalate (hereinafter also referred to as "DOP") or diisononyl phthalate (hereinafter also referred to as "DINP") as the plasticizer.

[0004] In addition, a urethane prepolymer containing xylylene diisocyanate (hereinafter also referred to as "XDI"), isophorone diisocyanate (hereinafter also referred to as "IPDI"), norbornene diisocyanate (hereinafter also referred to as "NBDI") or hexamethylene diisocyanate (hereinafter also referred to as "HDI") and polyoxypropylene polyol may be used as the base resin, the aromatic polyamine DETDA may be used as the curing agent, and DOP or DINP may be used as the plasticizer.

[0005] Currently, many of the hand-applied urethane rubber waterproof coating materials in use have as their base agents isocyanates (TDI, IPDI, HDI, etc.) designated as specific chemical substances, toxic substances, or deleterious substances, and some use MOCA, a specific chemical substance, as a curing agent. Most also use DOP as a plasticizer, which has been reported to be carcinogenic, reproductively toxic, and to act as an endocrine disruptor (e.g., Patent Documents 1 to 7).

[0006] The safety of the ingredients contained in these polyurethane rubber-based waterproofing coating materials was not a major issue 30 to 40 years ago when they first came onto the market, but in recent years, it has become necessary to consider their safety from the perspective of sustainability. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 08-143816 [Patent Document 2] Japanese Patent Application Publication No. 09-183942 [Patent Document 3] Japanese Patent Application Publication No. 07-330855 [Patent Document 4] Japanese Patent Application Publication No. 09-278859 [Patent Document 5] Japanese Patent Application Publication No. 06-49409 [Patent Document 6] Japanese Patent Application Publication No. 10-17819 [Patent Document 7] Japanese Patent Application Publication No. 2019-19210 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, it has been considered to manufacture urethane rubber-based coating waterproofing materials using isocyanate compounds other than TDI (a specified chemical substance), IPDI (designated toxic substance), and HDI (designated deleterious substance), which have been identified as having the risk of adversely affecting the human body and the environment. However, when these compounds are formulated, there is the problem that it is difficult to obtain the sufficient mechanical strength (coating film properties) required for coating waterproofing materials.

[0009] Therefore, an object of the present invention is to provide a room-temperature curing two-component coating composition that, after curing, achieves the sufficient tensile strength, tear strength, and tensile product required for urethane rubber-based waterproof coating materials, while aiming for a sustainable society and being considerate of both the human body and the environment. [Means for solving the problem]

[0010] The present invention provides a room-temperature-curable two-component coating composition comprising a base agent containing a urethane prepolymer and a curing agent, wherein the urethane prepolymer is a reaction product of a polyol and a polyisocyanate, the urethane prepolymer having a terminal isocyanate group derived from hydrogenated xylylene diisocyanate (hereinafter also referred to as "H-XDI"), the polyol containing polytetramethylene ether glycol, polyoxypropylene diol, and polyoxypropylene triol, and the isocyanate concentration (hereinafter also referred to as "NCO concentration") in the base agent is 0.9 to 1.90 mass%.

[0011] By using H-XDI as one of the raw materials for urethane prepolymers instead of the conventionally widely used TDI, IPDI, and HDI, it has been found that while being considerate of humans and the environment, it is easy to apply (i.e., it provides an easy-to-handle base viscosity and sufficient usable time), and after curing the room-temperature curing two-component coating composition, it achieves the sufficient tensile strength, tear strength, and tensile product generally required for polyurethane waterproofing coating membranes. Furthermore, by keeping the NCO concentration in the base resin low, it is possible to reduce the amount of expensive isocyanate raw materials used, which has the advantage of reducing costs.

[0012] That is, the room-temperature-curing two-component coating composition of the present invention does not require the use of plasticizers that have been reported to be specific chemical substances, toxic substances, deleterious substances, carcinogenic or reproductively toxic, or endocrine disrupting substances. When cured, the composition exhibits excellent general properties at 23°C, high-temperature properties at 60°C, and low-temperature properties at -20°C, and is also able to withstand environmental conditions caused by accelerated exposure. Furthermore, the room-temperature-curing two-component coating composition of the present invention also exhibits heat resistance and chemical resistance (acid resistance and alkali resistance). In addition, the addition of a curing accelerator allows the waterproofing applicator to more easily set the desired usable life for various seasons, environments, and construction regions throughout the year, resulting in a coating composition that is more suitable for hand application.

[0013] Here, in the past, there were urethane rubber-based coating waterproofing materials that used XDI and NBDI, which are not designated as specific chemical substances or poisonous or deleterious substances, but the resulting coating films did not have sufficient mechanical strength, and it was necessary to use DOP, etc., which has been pointed out as being carcinogenic, reproductively toxic, and acts as an endocrine disruptor, as a plasticizer formulated into the hardener.

[0014] Typically, formulating a urethane rubber-based coating waterproofing agent without using a phthalate diester plasticizer such as DOP has difficulty maintaining low viscosity of the base agent, especially at low temperatures. This often results in poor coating properties, such as elongation, environmental resistance (accelerated exposure test), and chemical resistance (acid and alkali resistance). Furthermore, maintaining the price as a general-purpose product is difficult. Therefore, the use of DOP, designated as a specified chemical substance, toxic, or deleterious substance, and posing concerns about its carcinogenicity, is unavoidable. Currently, there is no hand-applied urethane rubber-based coating waterproofing agent that complies with JIS A 6021:2011 and can be used sustainably in the future, aiming for a sustainable society. However, according to the present invention, even without the use of DOP, it is possible to ensure pot life and application workability, and achieve excellent elongation, environmental resistance (accelerated exposure test), and chemical resistance (acid and alkali resistance) after curing.

[0015] Furthermore, commonly used hand-applied, two-component, room-temperature-curing urethane rubber-based waterproofing coatings are applied by hand using a trowel, spatula, or roller. Therefore, after mixing the two components (base and curing agent) in a mixer, the coating must be applied to the waterproofed surface for at least 40 minutes. The pot life is generally the time it takes for the viscosity of the mixed base and curing agent to reach 100,000 mPa·s at 23°C. In the present invention, the urethane prepolymer in the base has a terminal isocyanate group of H-XDI, an isocyanate with a relatively slow urethanization and urea conversion reaction. Therefore, even when the active hydrogen of the curing agent is DETDA, a pot life of approximately 40 to 130 minutes can be achieved.

[0016] Hand-applied urethane rubber-based waterproofing coatings are applied regardless of the season or region. However, it is difficult to use the same hand-applied urethane rubber-based waterproofing coating in all seasons and regions; therefore, various versions are available for summer, winter, and low-temperature regions. The pot life (23°C, 100,000 mPa·S) of hand-applied urethane rubber-based waterproofing coatings is typically formulated to be approximately 40 to 130 minutes (e.g., HC Ecoproof i, manufactured by Hodogaya Construction Materials Co., Ltd., with a pot life of 75 minutes). For example, if the pot life is shorter than 40 minutes, curing begins while the base agent and curing agent are being mixed, making application impossible. On the other hand, if the pot life is longer than 130 minutes, concerns arise about curing the next day. If the next process cannot be carried out the following day, the construction period will be extended and workability will be reduced. When waterproofing is performed by hand application using a urethane rubber-based waterproof coating agent, the pot life of the urethane rubber-based waterproof coating agent is extremely important for workability, artificiality, and the overall waterproofing work.

[0017] The number average molecular weight of the polytetramethylene ether glycol is preferably 200 to 3500. When the number average molecular weight of the polytetramethylene ether glycol is within this range, a viscosity that makes the base agent easy to handle can be obtained, and as a result, the mixture of the base agent and the curing agent can be easily applied.

[0018] The number average molecular weight of the polyoxypropylene diol (hereinafter also referred to as "bifunctional PPG") is preferably 900 to 5100. When the number average molecular weight of the bifunctional PPG is within this range, the tensile strength, tensile product, tear strength, and elongation at break of the cured product obtained by curing the mixture of the base resin and the curing agent are further improved.

[0019] The number average molecular weight of the polyoxypropylene triol (hereinafter also referred to as "trifunctional PPG") is preferably 900 to 5100. When the number average molecular weight of the trifunctional PPG is within this range, the tensile strength, tensile product, tear strength, and elongation at break of the cured product obtained by curing the mixture of the base resin and the curing agent are further improved.

[0020] The base agent may further contain a polycarboxylic acid ester.

[0021] The polycarboxylic acid ester in the base material is preferably bis(2-ethylhexyl) adipate (DOA), which is more considerate to the human body and the environment.

[0022] The curing agent may include an aromatic polyamine and a polycarboxylic acid ester.

[0023] The aromatic polyamine is preferably 2,4-diamino-3,5-diethyltoluene, 2,6-diamino-3,5-diethyltoluene, or a mixture thereof, which is more considerate to the human body and the environment.

[0024] The polycarboxylic acid ester in the curing agent is preferably 1,2-cyclohexanedicarboxylic acid diisononyl ester (DHIN), 1,2-cyclohexanedicarboxylic acid bis(2-ethylhexyl) (DHEH), or a mixture thereof. When the polycarboxylic acid ester is such a compound, it can be more considerate to the human body and the environment.

[0025] The present invention also provides a waterproofing agent comprising the above room temperature curable two-component coating composition, which upon curing exhibits sufficient tensile strength, tear strength, and tensile product, while being less likely to adversely affect the human body or the environment.

[0026] The present invention also provides a waterproofing method comprising the step of forming a cured product of the waterproofing agent on a substrate. [Effects of the Invention]

[0027] According to the present invention, it is possible to provide a room-temperature-curing two-component coating composition that, after curing, achieves sufficient tensile strength, tear strength, and tensile product generally required for urethane rubber-based waterproof coating materials, while being considerate of the human body and the environment, aiming for a sustainable society. The room-temperature-curing two-component coating composition of the present invention, a waterproofing agent comprising this composition (a semi-finished (liquid) urethane rubber-based waterproof coating material), and a cured product thereof, are, in other words, compositions that, in order to realize a sustainable society, do not require the inclusion of specific chemical substances, poisons, deleterious substances, or phthalate diesters (DOPs), which have been identified as carcinogenic, toxic to reproductive health, and endocrine disrupting substances, as raw materials, and have general properties, environmental load characteristics, and chemical resistance characteristics, and a waterproofing agent comprising this composition (a semi-finished (liquid) urethane rubber-based waterproof coating material), and a cured product thereof. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0029] In this specification, "room temperature curing type" means that the composition cures at ambient temperature without the application of heat from the outside. The room temperature curing two-component coating composition of the present invention can also be called a room temperature curing environmentally friendly two-component coating composition, and "environmentally friendly" means that, in consideration of a sustainable society, the raw materials used contain little or no specified chemical substances, poisons, deleterious substances, or substances that have been identified as carcinogenic, reproductively toxic, or endocrine disrupting substances.

[0030] In this specification, the number average molecular weight refers to a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance, and can be measured under the following conditions. Equipment: TOSOH HCL-8320 (manufactured by Tosoh Corporation) Column: TSKgel G4000H + G2500H (7.5 mm I.D. x 30 cm) (Tosoh Corporation) Detector: RI Eluent:THF Injection volume: 100μL Flow rate: 1.0mL / min Measurement temperature: 40℃ Sample concentration: 0.3 wt / vol%

[0031] The room-temperature-curable two-component coating composition of the present invention is composed of a base agent and a curing agent, and the base agent contains a urethane prepolymer. The urethane prepolymer is a reaction product of a polyol containing polytetramethylene ether glycol (hereinafter also referred to as "PTMG"), polyoxypropylene diol (hereinafter also referred to as "bifunctional PPG"), and polyoxypropylene triol (hereinafter also referred to as "trifunctional PPG") with a polyisocyanate. The urethane prepolymer has terminal isocyanate groups derived from hydrogenated xylylene diisocyanate, and the isocyanate concentration (NCO concentration) in the base agent is 0.9 to 1.90 mass%.

[0032] When the polyol contains PTMG, the tensile strength, tensile product and tear strength of the cured product of the room temperature curable two-component coating composition are further improved.

[0033] The number average molecular weight of PTMG can be 200 or more, preferably 250 or more, and more preferably 450 or more. The number average molecular weight of PTMG can be 3500 or less, preferably 3000 or less, more preferably 2000 or less, and even more preferably 1000 or less. When the number average molecular weight of PTMG is within the above range, the viscosity of the base agent becomes easy to handle, and as a result, the mixture of the base agent and curing agent can be easily applied.

[0034] PTMG can be obtained by ring-opening polymerization of tetrahydrofuran (THF). Commercially available PTMG may also be used.

[0035] The PTMG content can be 1 equivalent percent or more, preferably 3 equivalent percent or more, more preferably 5 equivalent percent or more, and even more preferably 7 equivalent percent or more, based on the total amount of polyol (chemical equivalent). When the PTMG content is within this range, the tensile strength, tear strength, and tensile product of the cured product obtained by curing the mixture of the base agent and curing agent are further improved. The PTMG content can be 90 equivalent percent or less, based on the total amount of polyol, preferably 80 equivalent percent or less, more preferably 60 equivalent percent or less, even more preferably 40 equivalent percent or less, and particularly preferably 20 equivalent percent or less. When the PTMG content is within this range, the viscosity of the base agent can be made easy to handle, making the mixture of the base agent and curing agent easier to apply.

[0036] The bifunctional PPG is a compound having two hydroxyl groups. The number average molecular weight of the bifunctional PPG can be 900 or more, preferably 950 or more, and more preferably 1000 or more. When the number average molecular weight of the bifunctional PPG is within this range, the elongation at break of the cured product obtained by curing the mixture of the base agent and the curing agent is further improved. The number average molecular weight of the bifunctional PPG can be 5100 or less, preferably 4500 or less, and more preferably 4000 or less. When the number average molecular weight of the bifunctional PPG is within this range, the tensile strength, tensile product, and tear strength of the cured product obtained by curing the mixture of the base agent and the curing agent are further improved.

[0037] The content of the bifunctional PPG in the polyol can be 10 equivalent percent or more, preferably 20 equivalent percent or more, more preferably 25 equivalent percent or more, even more preferably 50 equivalent percent or more, and particularly preferably 65 equivalent percent or more, based on the total amount of polyol (chemical equivalent). When the content of the bifunctional PPG in the polyol is within this range, the tensile strength, tear strength, and tensile product of the cured product obtained by curing the mixture of the base agent and curing agent are further improved. The content of the bifunctional PPG in the polyol can be 95 equivalent percent or less, preferably 90 equivalent percent or less, and more preferably 85 equivalent percent or less. When the content of the bifunctional PPG in the polyol is within this range, the viscosity of the base agent can be made easy to handle, resulting in easier application of the mixture of the base agent and curing agent.

[0038] Trifunctional PPG is a compound having three hydroxyl groups. The number average molecular weight of the trifunctional PPG can be 900 or more, preferably 950 or more, and particularly preferably 1000 or more. When the number average molecular weight of the trifunctional PPG is within this range, the elongation at break of the cured product obtained by curing the mixture of the base agent and the curing agent is further improved. The number average molecular weight of the trifunctional PPG can be 5100 or less, preferably 4500 or less, and more preferably 4000 or less. When the number average molecular weight of the trifunctional PPG is within this range, the tensile strength, tensile product, and tear strength of the cured product obtained by curing the mixture of the base agent and the curing agent are further improved.

[0039] The content of trifunctional PPG in the polyol can be 1 equivalent % or more, preferably 5 equivalent % or more, more preferably 10 equivalent % or more, and even more preferably 15 equivalent % or more, based on the total amount of polyol (chemical equivalent). When the content of trifunctional PPG in the polyol is within this range, the tensile strength, tear strength, and tensile product of the cured product obtained by curing the mixture of the base agent and curing agent are further improved. The content of trifunctional PPG in the polyol can be 90 equivalent % or less, preferably 70 equivalent % or less, more preferably 50 equivalent % or less, and even more preferably 30 equivalent % or less. When the content of trifunctional PPG in the polyol is within this range, the viscosity of the base agent can be made easy to handle, resulting in easy application of the mixture of the base agent and curing agent.

[0040] The number average molecular weight of the bifunctional PPG and the number average molecular weight of the trifunctional PPG can each be 900 to 5100. When the number average molecular weight of the bifunctional PPG and the number average molecular weight of the trifunctional PPG are each within this range, the tensile strength, tensile product, and tear strength of the cured product obtained by curing the mixture of the base agent and the curing agent are further improved.

[0041] The polyol may contain other polyol components in addition to PTMG, difunctional PPG, and trifunctional PPG. The other polyol components may be, for example, polyhydric alcohols having 2 to 20 carbon atoms, polyoxyalkylene polyols (excluding PTMG, difunctional PPG, and trifunctional PPG) in which alkylene oxides having 2 to 4 carbon atoms are added to polyhydric alcohols having 2 to 20 carbon atoms or polyhydric phenols having 6 to 26 carbon atoms, polyester polyols, polycarbonate polyols, polydiene polyols (such as polybutadiene polyols), hydrogenated polydiene polyols, acrylic polyols, natural oil-based polyols (such as castor oil), or modified natural oil-based polyols.

[0042] The urethane prepolymer is a reaction product of the above-mentioned polyol and polyisocyanate and has terminal isocyanate groups derived from hydrogenated xylylene diisocyanate. Hydrogenated xylylene diisocyanate is formed by adding hydrogen to the benzene ring of xylylene diisocyanate to form a cyclohexane ring, and is expressed as bisisocyanatomethylcyclohexane, bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, H6-XDI, H-XDI, etc. The urethane prepolymer can be obtained, for example, by adding only H-XDI to the above-mentioned polyol in the equivalent ratio described below and heating and mixing to react. Furthermore, while the terminal isocyanate groups are derived from H-XDI, the urethane bond portion (the central portion of the urethane prepolymer) may contain groups derived from safe and environmentally friendly isocyanates such as MDI, XDI, NBDI, NDI, TMXDI, etc., in addition to H-XDI. To use multiple types of isocyanates and convert the terminal isocyanate of the urethane prepolymer to H-XDI-derived, the urethane prepolymerization reaction is carried out in two stages. In the first stage of urethane prepolymerization, for example, MDI, XDI, NBDI, NDI, TMXDI, or the like is charged with the polyol described above at an NCO / OH ratio of 0.5 or less, and all of the isocyanate groups are reacted with hydroxyl groups. The resulting urethane prepolymer reaction solution is subjected to a known NCO concentration measurement to confirm that it is 0.01% or less (all isocyanate groups have reacted and none remain). Next, in the second stage of urethane prepolymerization, hydrogenated xylylene diisocyanate is further added to the urethane prepolymer reaction solution, and a urethane prepolymerization reaction is carried out to prepare a urethane prepolymer whose terminal isocyanate groups are derived from H-XDI.

[0043] The NCO concentration in the base resin is 0.9 to 1.90% by mass. The NCO concentration can be, for example, 1.0% by mass or more or 1.1% by mass or more. When the NCO concentration is within this range, the viscosity of the base resin can be kept low and storage stability is improved. The NCO concentration can be, for example, 1.85% by mass or less or 1.75% by mass or less. When the NCO concentration is within this range, the coating finish (appearance) is good and the amount of expensive isocyanate raw material used can be reduced, thereby reducing the unit price for a general-purpose product. Furthermore, since there is no or very little unreacted isocyanate in the base resin of the present invention, further consideration can be given to the human body and the environment.

[0044] The equivalent ratio (NCO / OH) of the isocyanate groups (NCO groups) in the polyisocyanate to the hydroxyl groups (OH groups) in the polyol is preferably 1.20 or more, more preferably 1.30 or more, and even more preferably 1.40 or more. When the NCO / OH ratio is within this range, the storage stability of the base resin is improved. The NCO / OH ratio can be 1.70 or less, or 1.65 or less. When the NCO / OH ratio is within this range, a long usable time can be obtained.

[0045] Furthermore, to convert the terminal isocyanate groups of the urethane prepolymer into terminal isocyanate groups derived from H-XDI, the ratio of the NCO groups of H-XDI to the total NCO groups in the polyisocyanate may be, for example, 28 equivalent% or more. For example, when H-XDI and MDI are used as the polyisocyanate and the equivalent ratio (NCO groups / OH groups) is 1.20, the total ratio of the NCO groups of H-XDI and MDI to the total NCO groups in the polyisocyanate may be 28 equivalent% or more. When H-XDI and MDI are used as the polyisocyanate and the equivalent ratio (NCO groups / OH groups) is 1.70, the total ratio of the NCO groups of H-XDI and MDI to the total NCO groups in the polyisocyanate may be 78 equivalent% or more. When H-XDI and a polyisocyanate other than H-XDI and MDI (e.g., XDI, NBDI, TMXDI, NDI) are used as the polyisocyanate, and when the equivalent ratio (NCO group / OH group) is 1.20, the total proportion of NCO groups from H-XDI and polyisocyanates other than H-XDI and MDI relative to all NCO groups in the polyisocyanate should be 30% or more. When H-XDI and a polyisocyanate other than H-XDI and MDI (e.g., XDI, NBDI, TMXDI, NDI) are used as the polyisocyanate, and when the equivalent ratio (NCO group / OH group) is 1.65, the total proportion of NCO groups from H-XDI and polyisocyanates other than H-XDI and MDI relative to all NCO groups in the polyisocyanate should be 78% or more.

[0046] The ratio of the total equivalent weight of PTMG and trifunctional PPG to the equivalent weight of bifunctional PPG can be 0.1 or greater, preferably 0.2 or greater, and more preferably 0.3 or greater. When this ratio is within the above range, the tensile strength ratio and elongation at break measured in the tensile performance test of JIS A 6021:2011 "Waterproof Coatings for Architecture" after aging treatment are improved. The ratio of the total equivalent weight of PTMG and trifunctional PPG to the equivalent weight of bifunctional PPG can be 1.0 or less, preferably 0.8 or less, more preferably 0.6 or less, and even more preferably 0.5 or less. When this ratio is within the above range, a viscosity that facilitates handling of the base agent is obtained, resulting in easier application of the mixture of base agent and curing agent.

[0047] When synthesizing a urethane prepolymer, a catalyst to accelerate the urethane reaction may be added when, before, or after mixing the polyol and polyisocyanate. A catalyst may also be added to accelerate the reaction between the base resin and the curing agent. Typical urethane reaction accelerators, such as organic acids, organic acid metal salts, acid anhydrides, and imidazole compounds, can be used as catalysts to accelerate the urethane prepolymer synthesis reaction. However, it is preferable to use materials that are safe for humans and the environment. Examples of organic acids include propionic acid, 2-methylpentanoic acid, isononanoic acid, 2-ethylhexanoic acid, neodecanoic acid, naphthenic acid, oleic acid, linoleic acid, and linolenic acid. Examples of organic acid metal salts include zinc salts (e.g., K-KAT XK634 (manufactured by Kusumoto Chemicals Co., Ltd.)), bismuth salts (e.g., K-KAT XK628 (manufactured by Kusumoto Chemicals Co., Ltd.)), magnesium salts (e.g., magnesium 2-ethylhexanoate (manufactured by Fujifilm Wako Pharmaceuticals Co., Ltd.)), zirconium salts (e.g., K-KAT 6212 (manufactured by Kusumoto Chemicals Co., Ltd.)), calcium salts (e.g., Nikka Octix Calcium (manufactured by Nippon Chemical Industries Co., Ltd.)), barium salts (e.g., barium 2-ethylhexanoate (manufactured by Fujifilm Wako Pharmaceuticals Co., Ltd.)), and copper salts (e.g., copper 2-ethylhexanoate (manufactured by Fujifilm Wako Pharmaceuticals Co., Ltd.)). Zinc salts are particularly preferred as catalysts for accelerating the urethane prepolymer reaction. Organic acids, such as 2-ethylhexanoic acid, are preferred as catalysts for accelerating the reaction between the base agent and the curing agent.

[0048] The reaction temperature (heating temperature) of the polyol and polyisocyanate is preferably 50 to 100°C.

[0049] The reaction time of the polyol and the polyisocyanate can be 0.5 to 10 hours.

[0050] In addition to the urethane prepolymer, the base agent may further contain a plasticizer, solvent, or the like as a viscosity modifier to adjust the viscosity when the base agent and a curing agent (described later) are mixed. The base agent may further contain a catalyst and / or a retarder for efficiently reacting the isocyanate groups of the polyisocyanate with the hydroxyl groups of the polyol. The base agent may contain additives to improve the finish, durability, adhesion to other materials, etc. of the cured product obtained by curing the mixture of the base agent and curing agent, but these are preferably materials that are considerate of the human body and the environment.

[0051] Examples of plasticizers that can be used in the base resin include aliphatic dichlorates (e.g., diisononyl adipate (DINA), bis(2-ethylhexyl) adipate (DOA), etc.), cyclohexane derivatives (e.g., diisononyl 1,2-cyclohexanedicarboxylate (DHIN), bis(2-ethylhexyl) 1,2-cyclohexanedicarboxylate (DHEH), etc.), phosphates, trimellitates (e.g., tri(2-ethylhexyl) trimellitate (TOTM)), sebacic acid esters, epoxy fatty acid esters, glycol esters, animal oil-based fatty acid esters, petroleum- and mineral oil-based plasticizers, and alkylene oxide polymerization-based plasticizers. DOA is particularly preferred as the plasticizer contained in the base resin. DOA is highly compatible with the urethane prepolymer in the base resin of the present invention and maintains a viscosity that allows use year-round, regardless of summer or winter temperatures, eliminating the need for separate base resins for summer and winter use. As the plasticizer contained in the curing agent, it is particularly preferable to use DINA, DOA, DHIN, DHEH or a mixture thereof, and more preferably DHIN, DHEH or a mixture thereof.

[0052] Furthermore, it is preferable to avoid the use of phthalate ester plasticizers, such as phthalate diesters, di-2-ethylhexyl phthalate (DOP), di-terephthalate (DOTP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), and di-n-octyl phthalate (DNOP), which have been identified as carcinogenic, reproductively toxic, and endocrine disrupting. This allows for greater consideration of both human health and the environment. However, this does not mean that the use of all phthalate diesters is prohibited. As of 2021, in Japan, diisononyl phthalate (DINP) and di-terephthalate (DOTP) are frequently used as alternatives to di-2-ethylhexyl phthalate (DOP). While not a sustainable material, they can still be used given the current situation.

[0053] The total content of the above-mentioned plasticizers, solvents, catalysts, retarders, additives, etc. can be 10 to 25% by mass, or 15 to 20% by mass, based on the total mass of the main agent.

[0054] The viscosity of the base resin at 23°C can be 1000 mPa·s or higher, preferably 3000 mPa·s or higher, more preferably 5000 mPa·s or higher, and even more preferably 8000 mPa·s or higher. A viscosity within this range facilitates the maintenance of a consistent film thickness for the cured product (coating). The viscosity of the base resin at 23°C can be 60,000 mPa·s or lower, preferably 30,000 mPa·s or lower, and more preferably 15,000 mPa·s or lower. A viscosity within this range facilitates handling of the base resin, resulting in easier application of the base resin / curing agent mixture. The viscosity of the base resin can be measured using a rotational viscometer in accordance with JIS K 7301:1995, "Test Method for Tolylene Diisocyanate-Type Prepolymers for Thermosetting Urethane Elastomers, 6.2 Viscosity."

[0055] The curing agent may contain a plasticizer such as a polycarboxylic acid ester, and a crosslinking agent such as a polyalcohol or a polyamine. Examples of polycarboxylic acid esters include cyclohexane derivatives such as 1,2-cyclohexanedicarboxylic acid diisononyl ester (DHIN) and 1,2-cyclohexanedicarboxylic acid bis(2-ethylhexyl) (DHEH), as well as mixtures thereof. DHIN and DHEH are preferred because they are not substances subject to REACH regulations, and their use allows for greater consideration of the human body and the environment. Examples of polyamines include diethyltoluenediamine (2,4-diethyltoluenediamine, 2,6-diethyltoluenediamine), polyalkylene ether polyol-p-aminobenzoate, polytetramethylene ether glycol aminobenzoate, 4,4'-bis(sec-butylamine)diphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetraethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetraisopropyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-5,5'-diisopropyl-4,4'-diaminodiphenylmethane, 3,3'-dimethyl-5,5'-diisobutyl- Examples of the crosslinking agent include aromatic polyamines such as 4,4'-diaminodiphenylmethane, 3,3'-diethyl-5,5'-diisopropyl-4,4'-diaminodiphenylmethane, and 3,3'-diethyl-5,5'-diisobutyl-4,4'-diaminodiphenylmethane; alicyclic polyamines such as N,N'-di-sec-butyl-4,4'-methylenebis(cyclohexylamine), norbornene diamine, and N,N'-(dicyclohexylmethane-4,4'-diyl)-bisaspartic acid tetraethyl ester; and aliphatic polyamines such as triaminopropane, 2,2,4-trimethylhexamethylenediamine, 2-hydroxyethylethylenediamine, N,N'-(2-methylpentane-1,5-diyl)-bisaspartic acid tetraethyl ester, polyoxyalkyleneamines, and polyetheramines. These crosslinking agents may be used alone or in combination of two or more.The curing agent preferably contains an aromatic polyamine as a crosslinking agent, and more preferably contains diethyltoluenediamine (hereinafter referred to as "DETDA," which is 2,4-diamino-3,5-diethyltoluene, 2,6-diamino-3,5-diethyltoluene, or a mixture thereof.) DETDA is preferred because it is not a substance subject to REACH regulations, and the use of DETDA allows for greater consideration of the human body and the environment.

[0056] The content of the crosslinking agent contained in the curing agent based on the total mass of the curing agent can be 0.5 to 9.0 mass %, or 1.0 to 7.0 mass %.

[0057] In addition to the plasticizer and crosslinking agent, the curing agent may further contain solvents; catalysts; inorganic fillers such as calcium carbonate, aluminum hydroxide, barium hydroxide, talc, kaolin, silica, bentonite, zeolite, and diatomaceous earth; pigments such as chromium oxide, red iron oxide, iron oxide, carbon black, and titanium oxide; and additives such as wetting agents, dispersants, anti-settling agents, light stabilizers, antifoaming agents, surface conditioners, adhesion promoters, and weather resistance promoters. The plasticizer may be the same as the plasticizers listed as those that can be contained in the base resin. Calcium carbonate is preferred as the inorganic filler. Examples of calcium carbonate include heavy calcium carbonate, light calcium carbonate, and surface-treated colloidal calcium carbonate.

[0058] The mixture is cured by mixing the base agent and the curing agent. The resulting cured product can be used as part or all of a waterproofing material. That is, a waterproofing material can be obtained that includes a cured mixture of the base agent and the curing agent.

[0059] The waterproof material described above is excellent in tensile strength, tear strength, tensile product, and elongation at break, and is a high-strength and highly elongated waterproof material. Furthermore, the waterproof material described above is safe, taking into consideration the human body and the environment.

[0060] A waterproofing method according to one embodiment includes a step of forming a cured product of a waterproofing agent on a substrate. In other words, a waterproof material can be manufactured by forming a cured product of the waterproofing agent on a substrate. The step of forming the cured product of the waterproofing agent can include a step of applying a mixture of the main agent and curing agent contained in the waterproofing agent to the substrate (application step), and can further include a step of mixing the main agent and curing agent contained in the waterproofing agent (mixing step) before the application step.

[0061] In the mixing step, the temperature (environmental temperature) when mixing the base agent and the curing agent can be, for example, -10 to 40°C.

[0062] The mixing ratio of the base agent to the curing agent can be 1:1-5 by mass, preferably 1:1-4, and more preferably 1:1-3.

[0063] When the curing agent contains a polyamine, the equivalent ratio of NCO groups in the base agent to the amino groups (NH2 groups) contained in the curing agent (NCO groups / NH2 groups) in the base agent when mixing the curing agent in the mixing step is preferably 0.8 to 1.5, more preferably 0.9 to 1.4, and even more preferably 1.0 to 1.3. When the NCO groups / NH2 groups ratio is in this range, a cured product with superior tensile strength, tear strength, and tensile product can be obtained.

[0064] In the application process, the mixture of the base agent and the curing agent is applied to a substrate before the mixture hardens. The substrate is not particularly limited and can be a wall surface, floor surface, or the like of a building such as a house or building. The mixture of the base agent and the curing agent according to this embodiment can have a sufficient usable time, making it particularly suitable for application by hand (hand coating). Hand coating refers to application to the substrate by hand using a trowel, spatula, roller, brush, or the like. In other words, hand coating can be performed in the mixing process. Hand coating includes application by machine using an automatic mixing device such as a static mixer or dynamic mixer, as well as application using tools such as a roller, ricin gun, airless gun, or brush. This does not prevent the mixture according to this embodiment from being applied to a substrate by, for example, spray coating.

[0065] The mixture of the base material and the curing agent can be applied to a substrate so that the thickness of the cured product obtained by curing the mixture will be 0.05 to 10 mm, preferably 0.1 to 5 mm, and more preferably 0.5 to 4.0 mm.

[0066] The room-temperature-curable two-component coating composition of this embodiment can be said to have a sufficiently long pot life, since it takes, for example, 40 minutes or more for the viscosity of the mixture of the base agent and the curing agent at 23°C to reach 100,000 mPa·s. In terms of pot life, it is more preferable that the mixture of the base agent and the curing agent reaches a viscosity of 100,000 mPa·s at 23°C in 60 minutes or more.

[0067] The waterproofing material obtained by the above-mentioned method can be used not only as a waterproofing material but also as a flooring material for sports facilities etc. where high strength and high load performance are required, a covering material for buildings etc., and further as a rust preventative material, etc. Depending on the application, it is also possible to add an organic solvent that is considerate of the human body and the environment to the mixture before application depending on the workability.

[0068] Regardless of the type of base substrate, it is preferable to provide a primer layer between the substrate and the cured product that exhibits adhesion to both the substrate and the cured product. For example, if the substrate is mortar, concrete, ALC, or plywood, it is preferable to use a urethane resin primer, such as HC Primer CB30 or CB30III, or an epoxy resin primer, such as HC Primer EPO (manufactured by Hodogaya Construction Materials Co., Ltd.). For example, if the substrate is stone, glass, porcelain tile, iron, aluminum, stainless steel, galvanized iron plate, copper plate, FRP, or epoxy resin, it is preferable to use a urethane resin primer, such as Millionate MS-60, or an epoxy resin primer, such as HC Primer EPO (manufactured by Hodogaya Construction Materials Co., Ltd.). If the base substrate is vinyl chloride, it is preferable to use a urethane resin primer, such as Millionate MS-60 (manufactured by Hodogaya Construction Materials Co., Ltd.). If the base substrate is lead, it is preferable to use an epoxy resin primer, such as HC Primer EPO (manufactured by Hodogaya Construction Materials Co., Ltd.). If the base material is an EPDM rubber sheet, it is preferable to use, for example, Millionate MS-70 (manufactured by Hodogaya Construction Materials Co., Ltd.) As a primer that is considerate of humans and the environment, HC Primer EPO, which is an epoxy resin primer that does not contain any organic solvents or specific chemical substances, is preferred.

[0069] The waterproofing material according to this embodiment can be coated with a topcoat layer on the surface of the cured product opposite the substrate. This can protect the product from direct sunlight and improve its design. For the topcoat layer, it is preferable to use an acrylic urethane resin topcoat that does not contain specific chemical substances and does not comply with the Organic Solvent Poisoning Prevention Law, such as HC Ecotop Zero or HC Ecotop Cool Zero (manufactured by Hodogaya Construction Materials Co., Ltd.). [Example]

[0070] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0071] In the table below, the abbreviations in the table represent the following components. (1) H-XDI: 1,3-bis(isocyanatomethyl)cyclohexane (trade name "Takenate 600", manufactured by Mitsui Chemicals, Inc.), XDI: 1,3-bis(isocyanatomethyl)benzene (trade name "Takenate 500", manufactured by Mitsui Chemicals, Inc.), NBDI: norbornenemethane diisocyanate (trade name "NBDI", manufactured by Mitsui Chemicals, Inc.), NDI: 1,5-diisocyanatonaphthalene (trade name "NDI", manufactured by Mitsui Chemicals, Inc.) (2) PTMG-250: (number average molecular weight 250, trade name "PTMG-250", manufactured by Mitsubishi Chemical Corporation), PTG-650: polytetramethylene ether glycol (number average molecular weight 650, trade name "PTG-650SN", manufactured by Hodogaya Chemical Co., Ltd.), PTG-1000: polytetramethylene ether glycol (number average molecular weight 1000, trade name "PTG-1000SN", manufactured by Hodogaya Chemical Co., Ltd.), PTG-2900: polytetramethylene ether glycol (number average molecular weight 2900, trade name "PTG-2900SN", manufactured by Hodogaya Chemical Co., Ltd.) (3) PPG-T1500: polyoxypropylene triol (number average molecular weight 1500, trade name "Actocol T-1500", manufactured by Mitsui Chemicals SKC Polyurethanes Inc.), PPG-T3000S: polyoxypropylene triol (number average molecular weight 3000, trade name "Actocol T-3000", manufactured by Mitsui Chemicals SKC Polyurethanes Inc.) (4) PPG-D1000: polyoxypropylene diol (number average molecular weight 1000, trade name "Actocol D-1000", manufactured by Mitsui Chemicals SKC Polyurethanes Inc.), PPG-D2000: polyoxypropylene diol (number average molecular weight 2000, trade name "Actocol D-2000", manufactured by Mitsui Chemicals SKC Polyurethanes Inc.), PPG-D3000: polyoxypropylene diol (number average molecular weight 3000, trade name "Actocol D-3000", manufactured by Mitsui Chemicals SKC Polyurethanes Inc.) (5) BPX33: Bisphenol A-propylene oxide adduct (trade name "ADEKA Polyether BPX-33", manufactured by ADEKA Corporation)

[0072] <Preparation of Base Agent: Examples 1 to 16, Comparative Examples 1 to 9> A metal reactor equipped with a stirrer, thermometer, condenser, and nitrogen seal tube was charged with the polyol, plasticizer (DOA), additives (antifoaming agent (Florene AC2200HF manufactured by Kyoeisha Chemical Co., Ltd.) and isoparaffinic hydrocarbon (IP Solvent 1620 manufactured by Idemitsu Kosan Co., Ltd.)) and catalyst (K-KAT XK634 manufactured by Kusumoto Chemical Co., Ltd.) listed in Tables 1, 2, and 4 in the amounts listed in the tables. The mixture was then dehydrated under reduced pressure at 95-105°C for 1 hour. After cooling to a liquid temperature of 40°C or below, a predetermined amount of H-XDI was added, and the mixture was heated to 80°C with stirring for 1-2 hours until the reaction was complete. The liquid after the reaction was cooled to room temperature, and a viscosity modifier and other additives were added. The mixture was homogenized with stirring to obtain a base resin (urethane prepolymer) with terminal isocyanate groups of H-XDI.

[0073] <Preparation of Main Agent: Examples 17 to 20> A metal reactor equipped with a stirrer, thermometer, condenser, and nitrogen seal tube was charged with the polyol, plasticizer (DOA), additives (antifoaming agent (Florene AC2200HF manufactured by Kyoeisha Chemical Co., Ltd.) and isoparaffinic hydrocarbon (IP Solvent 162 manufactured by Idemitsu Kosan Co., Ltd.)) and catalyst (K-KAT-XK-634 manufactured by Kusumoto Chemical Co., Ltd.) listed in Table 3 in the amounts listed in the table, and dehydration was carried out under reduced pressure at 95 to 105°C for 1 hour. After cooling to a liquid temperature of 40°C or less, MDI, XDI, or NBDI was gradually added, and the mixture was heated at 80°C with stirring for 1 to 2 hours until the NCO concentration reached 0 to 0.1%. After cooling and checking the NCO concentration, H-XDI was gradually added, and the mixture was heated at 80°C with stirring for 1 to 2 hours until the reaction was complete. The liquid after the reaction was cooled to room temperature, and a viscosity modifier and the like were added and homogenized with stirring to obtain a base material (urethane prepolymer) in which the terminal isocyanate was H-XDI.

[0074] <Measurement of NCO concentration of main agent> 1 g of the obtained base compound was weighed into a 300 ml Erlenmeyer flask and added to 15 ml of 0.2 N di-n-butylamine toluene solution and dissolved and mixed. A few drops of bromophenol blue and 70 ml of methanol were added, and the resulting mixture was titrated with 0.1 N hydrochloric acid solution. The NCO concentration (mass%) can be calculated using the following formula. NCO concentration (mass%) = (42 × (blank titration value − 0.1 N hydrochloric acid solution titration value) × 0.1 N hydrochloric acid solution factor × 0.1 × 100) ÷ (sample mass × 1000)

[0075] <Polyol equivalent ratio in base resin> The equivalent weight of the base raw materials (PTMG, bifunctional PPG, and trifunctional PPG) is the molecular weight per reactive group of each raw material. The equivalent weight is calculated by dividing the amount used by the molecular weight per equivalent. The equivalent ratios (%) listed in Tables 1 to 4 represent the percentage of the equivalent weight of PTMG, bifunctional PPG, or trifunctional PPG relative to the total equivalent weight of PTMG, bifunctional PPG, and trifunctional PPG. The (PTMG + Triol):Diol equivalent ratio (%) represents the ratio of the total equivalent percentage of PTMG and trifunctional PPG (Triol) to the equivalent percentage of bifunctional PPG (Diol) alone. The (PTG + Triol) / Diol equivalent ratio represents the value obtained by dividing the total equivalent percentage of PTMG and trifunctional PPG (Triol) by the equivalent percentage of bifunctional PPG (Diol) alone.

[0076] <Preparation of Curing Agent: Examples 1 to 20, Comparative Examples 1 to 9> The DETDA (Ethacure 100 manufactured by Albemarle Corporation), plasticizers (DHIN and DHEH), additives (antidegradant (ADEKA STAB LA-72 manufactured by ADEKA Corporation), toner (Gray Toner manufactured by Nikko Bix Co., Ltd.), and zeolite (USKK L Powder manufactured by Nion Showa Co., Ltd.)), catalyst (2-ethylhexanoic acid manufactured by Fujifilm Wako Pharmaceutical Co., Ltd.), and inorganic filler (heavy calcium carbonate (SUPER#1500 manufactured by Maruo Calcium Co., Ltd.) and light calcium carbonate (HOMOCAL DM manufactured by Shiraishi Kogyo Co., Ltd.)) were charged into a dissolver in the amounts shown in the table and mixed at room temperature for 60 minutes to obtain a curing agent.

[0077] <Preparation of coating film (cured product) and evaluation of usable time> The resulting base resin and curing agent were mixed in a constant temperature and humidity chamber at a room temperature of 23°C and a humidity of 50% to achieve the mass mixing ratios listed in Tables 1 to 4. The resulting mixed mixture was applied to a release-treated substrate to a thickness of 2 mm and then cured for 7 days in the same chamber to obtain a coating (cured product). The pot life was measured in the same chamber at a room temperature of 23°C and a humidity of 50% according to JIS K 7301:1995, "Test Method for Tolylene Diisocyanate-Type Prepolymers for Thermosetting Urethane Elastomers, 6.2 Viscosity," using a rotational viscometer (Toki Sangyo Co., Ltd., Model BH II). The measurement results are shown in Tables 1 to 4.

[0078] <Evaluation of tensile properties of coating film (cured product)> The tensile strength (testing temperature: -20°C, 23°C, and 60°C), elongation at break (testing temperature: 23°C), grip elongation at break (testing temperature: -20°C, 23°C, and 60°C), and tensile product (testing temperature: 23°C) of the coating films (cured products) obtained in the Examples and Comparative Examples were measured in accordance with the tensile performance test of JIS A 6021:2011 "Waterproof coating materials for architecture." The results are shown in Tables 1 to 4.

[0079] The coating films (cured products) obtained in the examples and comparative examples were subjected to aging treatments (heat treatment, accelerated exposure treatment, alkali treatment, or acid treatment), and then the tensile strength ratio and elongation at break were measured in accordance with the tensile performance test after aging treatments in JIS A 6021:2011 "Waterproof coating materials for architecture." The results are shown in Tables 1 to 4.

[0080] <Evaluation of tear performance of cured product> The tear strength (test temperature: 23°C) of the coating films (cured products) obtained in the examples and comparative examples was measured in accordance with the tear performance test of JIS A 6021:2011 "Waterproof coating materials for architecture." The results are shown in Tables 1 to 4.

[0081] <Hardness evaluation> The hardness of the coating films (cured products) obtained in the examples and comparative examples was measured using an Asker Rubber Hardness Tester Type A (manufactured by Kobunshi Keiki Co., Ltd.) (in the tables, this is referred to as "A hardness.") The results are shown in Tables 1 to 4.

[0082] The thermal expansion and contraction performance (expansion rate %) of the coating film (cured product) was measured based on JIS A 6021:2011 "Waterproof coating materials for construction."

[0083] [Table 1]

[0084] [Table 2]

[0085] [Table 3]

[0086] [Table 4]

[0087] As shown in Examples 1 to 3, by adjusting the amount of catalyst (organic acid) added, it is possible to adjust the pot life from a longer pot life (120 minutes) that can withstand long-term use, to the pot life of a commonly used urethane rubber-based urethane coating film waterproofing agent (76 minutes), to a shorter pot life (65 minutes) that is preferred by experts.The results of Examples 1 to 3 clearly show that the room-temperature-curing two-component coating composition of the present invention has useful applications as a urethane rubber-based coating film waterproofing agent.

[0088] As shown in Examples 4 to 16 and Comparative Examples 1 to 9, it is important that the NCO concentration is 0.9 to 1.90 mass % and that the polyols constituting the urethane prepolymer in the base resin contain polytetramethylene ether glycol, polyoxypropylene diol, and polyoxypropylene triol, and it is clear that this allows the cured product to exhibit high coating film properties (conforming to the high elongation type of JIS A 6021:2011).

[0089] As shown in Examples 17 to 20, if the terminal isocyanate of the urethane prepolymer in the base resin is H-XDI, the required pot life can be secured at the time of application, and it is clear that high coating film properties (conforming to the high elongation type of JIS A 6021:2011) can be obtained even if the urethane bond other than the terminal is composed of other isocyanates.

[0090] All of Examples 1 to 20 met the high-elongation standards (standards for tensile performance, tear performance, heat expansion / contraction performance, and tensile performance after aging treatment) specified in JIS A 6021:2011 "Waterproof coating materials for architecture." It was found that the cured product of the room-temperature-curing two-component coating composition according to the present invention exhibits sufficient physical properties generally required for polyurethane waterproof coating materials. On the other hand, none of Comparative Examples 1 to 9 met all of the high-elongation standards. [Industrial Applicability]

[0091] According to the present invention, it is possible to provide a room-temperature curing two-component coating composition that, after curing, achieves sufficient tensile strength, tear strength, and tensile product generally required for polyurethane waterproof coating membranes, while being safe for humans and the environment.

Claims

1. It consists of a base agent containing a urethane prepolymer and a curing agent. the urethane prepolymer is a reaction product of a polyol and a polyisocyanate; the urethane prepolymer has a terminal isocyanate group derived from hydrogenated xylylene diisocyanate, The polyol includes polytetramethylene ether glycol, polyoxypropylene diol, and polyoxypropylene triol, The isocyanate concentration in the base resin is 0.9 to 1.90% by mass, the content of the polyoxypropylene triol in the polyol is 5 to 50 equivalent % based on the total amount of the polyol; The room temperature curable two-component coating composition, wherein the number average molecular weight of the polytetramethylene ether glycol is 2,900 or more, or the number average molecular weight of the polyoxypropylene diol is 2,000 or more.

2. 2. The room temperature curable two-component coating composition according to claim 1, wherein the polytetramethylene ether glycol has a number average molecular weight of 200 to 3,500.

3. 3. The room-temperature curable two-component coating composition according to claim 1, wherein the polyoxypropylene diol has a number average molecular weight of 900 to 5,100.

4. 4. The room-temperature curable two-component coating composition according to claim 1, wherein the polyoxypropylene triol has a number average molecular weight of 900 to 5,100.

5. 5. The room-temperature curable two-component coating composition according to claim 1, wherein the main component further comprises a polycarboxylic acid ester.

6. 6. The room-temperature curable two-component coating composition according to claim 5, wherein the polycarboxylic acid ester is bis(2-ethylhexyl) adipate.

7. 7. The room-temperature curable two-component coating composition according to claim 1, wherein the curing agent comprises an aromatic polyamine and a polycarboxylic acid ester.

8. 8. The room-temperature curable two-component coating composition according to claim 7, wherein the aromatic polyamine is 2,4-diamino-3,5-diethyltoluene, 2,6-diamino-3,5-diethyltoluene, or a mixture thereof.

9. 9. The room-temperature curable two-component coating composition according to claim 7, wherein the polycarboxylic acid ester in the curing agent is 1,2-cyclohexanedicarboxylic acid diisononyl ester, 1,2-cyclohexanedicarboxylic acid bis(2-ethylhexyl) ester, or a mixture thereof.

10. A waterproofing agent comprising the room temperature curable two-component coating composition according to any one of claims 1 to 9.

11. A waterproofing method comprising the step of forming a cured product of the waterproofing agent according to claim 10 on a substrate.

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