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

Abstract

To provide a room temperature-curable two-pack coating composition excellent in low-temperature storage properties.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 isophorone diisocyanate. The polyol contains a polyoxypropylene polyol and polytetramethylene ether glycol. The polytetramethylene ether glycol has a number average molecular weight of 900 or less. The equivalent ratio of the total amount of isocyanate groups of the isophorone diisocyanate to the total amount of hydroxyl groups of the polyol is 1.50-1.98.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Polyurethane waterproofing materials (coated waterproofing materials) are used as waterproofing materials for building rooftops, verandas, corridors, etc., and are also widely used for applications such as floor coating materials and elastic paving for sports facilities. Known examples of polyurethane waterproofing materials include those shown in Patent Document 1, which are obtained by mixing a base agent containing an isocyanate-terminated prepolymer with a curing agent, applying the mixture, and curing the mixture. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-143816 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the investigations of the present inventors, some two-component coating compositions containing the above-mentioned base agent and curing agent undergo deterioration such as the formation of precipitates in low-temperature environments, and such coating agents are difficult to store stably when used in winter or in cold regions.

[0005] Therefore, an object of the present invention is to provide a room temperature curable two-component coating composition that has excellent storage stability at low temperatures. [Means for solving the problem]

[0006] 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 isophorone diisocyanate, the polyol containing a polyoxypropylene polyol and a polytetramethylene ether glycol, the polytetramethylene ether glycol having a number-average molecular weight of 900 or less, and an equivalent ratio of the total amount of isocyanate groups of the isophorone diisocyanate to the total amount of hydroxyl groups of the polyol of 1.50 to 1.98. Here, "room-temperature-curable" means that the composition cures at ambient temperature (e.g., 0°C to 45°C) without the application of external heat.

[0007] Urethane prepolymers are compounds obtained by reacting a polyol compound with an excess of an isocyanate compound. Generally, the molecular weight of a urethane prepolymer tends to increase when the equivalent ratio (NCO / OH) of the total isocyanate groups (NCO groups) in the isocyanate compound to the total hydroxyl groups (OH groups) in the polyol compound is small. Furthermore, when comparing polymers of the same components, polymers with higher molecular weights are generally less soluble in solvents. Furthermore, since solubility generally decreases at low temperatures, polymers tend to precipitate from solvents at low temperatures. Therefore, to prevent urethane prepolymers from precipitating even when the base agent is stored at low temperatures, i.e., to improve the low-temperature storage properties of the base agent, it is usually expected to increase the NCO / OH ratio. For example, increasing the NCO / OH ratio to 2 or more can improve the low-temperature storage properties of the base agent. However, the present inventors have newly discovered that the base resin of the present invention has an NCO group / OH group ratio of 1.50 to 1.98, and has excellent low-temperature storage properties despite having a larger molecular weight than urethane prepolymers with an NCO group / OH group ratio of 2 or more. The mechanism by which such low-temperature stability is obtained is not clear, but the present inventors speculate that it is due to the fact that the number-average molecular weight of the polytetramethylene ether glycol is set to 900 or less and the NCO group / OH group ratio is set to 1.50 to 1.98.

[0008] The number average molecular weight of the polytetramethylene ether glycol is preferably 150 to 700. When the number average molecular weight of the polytetramethylene ether glycol is within this range, the low-temperature storage property of the base agent is further improved, as described above.

[0009] The polyoxypropylene polyol may contain a polyoxypropylene diol.

[0010] The present invention also provides a waterproofing agent comprising the above-mentioned room temperature curable two-component coating composition. Such a waterproofing agent has excellent low-temperature storage properties.

[0011] 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]

[0012] According to the present invention, it is possible to provide a room temperature curable two-component coating composition that has excellent low-temperature storage properties. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0014] In the present invention, the number average molecular weight means a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance, and can be measured under the following conditions. Apparatus: 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%

[0015] The urethane prepolymer is a reaction product of a polyol and isophorone diisocyanate (hereinafter also referred to as "IPDI"), the polyol containing polyoxypropylene polyol and polytetramethylene ether glycol (hereinafter also referred to as "PTMG"), the number average molecular weight of the PTMG being 900 or less, and the equivalent ratio of the total amount of isocyanate groups of the isophorone diisocyanate to the total amount of hydroxyl groups of the polyol being 1.50 to 1.98.

[0016] The number-average molecular weight of PTMG can be 150 or more, preferably 250 or more, and more preferably 450 or more. The number-average molecular weight of PTMG can be 900 or less, preferably 800 or less, and more preferably 700 or less. When the number-average molecular weight of PTMG is within the above-mentioned range, the NCO group / OH group ratio is in the range of 1.50 to 1.98, and even though the molecular weight of the urethane prepolymer is large, the low-temperature storage stability of the base agent containing this urethane prepolymer is improved. Furthermore, when the number-average molecular weight of PTMG is within the above-mentioned range, the base agent has a viscosity that makes it easy to handle, and as a result, the mixture of the base agent and curing agent can be easily applied.

[0017] PTMG can be obtained by ring-opening polymerization of tetrahydrofuran (THF). Commercially available PTMG may also be used.

[0018] 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.

[0019] The number-average molecular weight of the polyoxypropylene polyol can be 300 or more, preferably 400 or more, and more preferably 500 or more. When the number-average molecular weight of the polyoxypropylene polyol 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 improved. The number-average molecular weight of the polyoxypropylene polyol can be 6000 or less, preferably 5000 or less, and more preferably 4000 or less. When the number-average molecular weight of the polyoxypropylene polyol 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.

[0020] The polyoxypropylene polyol can be di- to hexa-functional. Here, di- to hexa-functional means having 2 to 6 hydroxyl groups in one molecule. These polyoxypropylene polyols are preferably di- to tri-functional, and it is also possible to use only difunctional ones. Alternatively, a mixture of a difunctional polyoxypropylene polyol (hereinafter also referred to as "polyoxypropylene diol") and a trifunctional polyoxypropylene polyol (hereinafter also referred to as "polyoxypropylene triol") can be used. The molecular shape may be linear or branched.

[0021] The content of polyoxypropylene polyol 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 polyoxypropylene polyol 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 polyoxypropylene polyol 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 polyoxypropylene polyol 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.

[0022] The polyol may contain other polyol components in addition to PTMG and polyoxypropylene polyol. The other polyol components may be, for example, polyhydric alcohols having 2 to 20 carbon atoms, polyoxyalkylene polyols (excluding the above-mentioned PTMG and polyoxypropylene polyols) 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.

[0023] The equivalent ratio (NCO / OH) of the total amount of isocyanate groups (NCO groups) in the IPDI to the total amount of hydroxyl groups (OH groups) in the polyol is 1.50 or more, and can be 1.70 or more. When the NCO / OH ratio is in this range, a viscosity that makes the base resin easy to handle can be obtained. The NCO / OH ratio is 1.98 or less, and can be 1.90 or less, or 1.85 or less. When the NCO / OH ratio is in this range, a long pot life can be obtained.

[0024] The content of isocyanate groups in the urethane prepolymer can be 0.7% by mass or more, 0.9% by mass or more, or 1.0% by mass or more. When the content of isocyanate groups is within this range, the tensile strength, tensile product, and tear strength of the cured product obtained by curing the mixture of the base resin and the curing agent are further improved. The content of isocyanate groups in the urethane prepolymer can be 7.0% by mass or less, 6.0% by mass or less, or 5.0% by mass or less. When the content of isocyanate groups is within this range, the usable time can be maintained long and costs tend to be reduced.

[0025] The urethane prepolymer can be obtained, for example, by adding IPDI to a polyol in a predetermined equivalent ratio and reacting the mixture. The reaction may be heated, and a catalyst such as a urethanization catalyst may be added.

[0026] The reaction temperature (heating temperature) of the polyol and IPDI can be 100° C. or lower, 90° C. or lower, or 80° C. or lower. The lower limit of the reaction temperature (heating temperature) is not particularly limited, but can be, for example, 30° C. or higher.

[0027] The reaction time of the polyol and IPDI can be 0.5 to 7 hours.

[0028] A catalyst may be added simultaneously with, before, or after the mixing of the polyol and IPDI. Examples of the catalyst that can be used include urethane-forming catalysts (urethane-forming reaction accelerators) such as organic acids, organic acid metal salts, acid anhydrides, and imidazole compounds. 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, bismuth salts, magnesium salts, zirconium salts, calcium salts, barium salts, and copper salts. It is preferable to use tin salts such as dibutyltin dilaurate and dioctyltin laurate as the catalyst.

[0029] 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 the curing agent described below are mixed. The base agent may further contain a catalyst and / or 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.

[0030] Examples of plasticizers that can be included in the base resin include cyclohexane derivatives (diisononyl 1,2-cyclohexanedicarboxylate (DHIN), bis(2-ethylhexyl) 1,2-cyclohexanedicarboxylate (DHEH), etc.), aliphatic dichlorates (diisononyl adipate (DINA)), terephthalic acid diester (DOTP), phosphate esters, trimellitic acid esters, sebacic acid esters, epoxy fatty acid esters, glycol esters, animal oil-based fatty acid esters, petroleum and mineral oil-based plasticizers, alkylene oxide polymerization-based plasticizers, and phthalic acid diesters (di-2-ethylhexyl phthalate (DOP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), and di-normal-octyl phthalate (DNOP)). When phthalate diesters are not used as plasticizers, it is possible to obtain a room temperature curable two-component coating composition that is safer and more considerate of the human body and the environment.

[0031] The total content of the above-mentioned plasticizers, solvents, catalysts, retarders, additives, etc. can be 0 to 25% by mass, or 0 to 20% by mass, based on the total mass of the main agent.

[0032] 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 7000 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 50,000 mPa·s or lower, and more preferably 20,000 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."

[0033] The curing agent may contain a hydroxyl compound such as a polyhydric alcohol, or a crosslinking agent such as a polyamine. Examples of polyamines include diethyltoluenediamine (2,4-diethyltoluenediamine, 2,6-diethyltoluenediamine), phenylenediamine, xylylenediamine, 2,4-tolylenediamine, 2,6-tolylenediamine, MOCA-based polyamines (MOCA and modified MOCA), polyalkylene ether polyol-p-aminobenzoate, polytetramethylene ether glycol aminobenzoate, 1,3,5-triisopropyl-2,4-diaminobenzene, 1-methyl-3,5-diisopropyl-2 ,4-diaminobenzene, 1-methyl-3,5-diisopropyl-2,6-diaminobenzene, 1-ethyl-3,5-diisopropyl-2,4-diaminobenzene, 1-ethyl-3,5-diisopropyl-2,6-diaminobenzene, methylenebis(methylthio)benzenediamine, N,N'-disecondarybutyl-p-phenylenediamine, 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-4,4'-diaminodiphenylmethane, 3,3'-diethyl-5,5'-diisopropyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-5,5'-diisobutyl-4, Aromatic polyamines such as 4'-diaminodiphenylmethane, alicyclic polyamines such as N,N'-di-sec-butyl 4,4'-methylenebis(cyclohexylamine), isophoronediamine, norbornenediamine, N,N'-(dicyclohexylmethane 4,4'-diyl)-bisaspartic acid tetraethyl ester, ethylenediamine, trimethylenediamine, triethylenetetramine, diethylenetriamine, triaminopropane, 2,2,4-trimethylhexamethylenediamine, 2-hydroxyethylethylenediamine, N,Aliphatic polyamines such as N'-(2-methylpentane-1,5-diyl)-bisaspartic acid tetraethyl ester, polyoxyalkyleneamine, and polyetheramine can be used. These crosslinking agents can 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 also referred to as "DETDA"). When DETDA is used as a crosslinking agent, it is highly safe and is not subject to restrictions on production or use.

[0034] The content of the crosslinking agent contained in the curing agent can be 1 to 10 mass % based on the total mass of the curing agent, and can be 2 to 8 mass %.

[0035] In addition to the crosslinking agent, the curing agent may further contain additives such as plasticizers, 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 wetting agents, dispersants, anti-settling agents, light stabilizers, antifoaming agents, surface conditioners, adhesion promoters, and weather resistance promoters. 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.

[0036] By mixing the above-mentioned base agent and curing agent, the mixture hardens and a coating film (also referred to as a "waterproofing material"; the same applies below) can be obtained. The waterproofing agent of this embodiment has excellent tensile strength, tear strength, tensile product, and elongation at break, and is capable of forming a high-strength, highly elongated coating film. Furthermore, the coating film obtained with the waterproofing agent of this embodiment is safe, taking into consideration the human body and the environment.

[0037] The waterproofing method according to this embodiment includes a step of forming a cured product of the above-described waterproofing agent on a substrate. This waterproofing method may include a mixing step of mixing a main agent of the waterproofing agent with a curing agent, and a coating step of coating the mixture on the substrate to form a cured product (corresponding to a "coating film" or "waterproofing material").

[0038] In the mixing step, the temperature (environmental temperature) when mixing the base agent and the curing agent can be, for example, -5 to 45°C.

[0039] The mixing ratio of the base agent to the curing agent can be 1:1 to 1:4 by mass, preferably 1:1 to 1:3, and more preferably 1:1.

[0040] When the curing agent contains a crosslinking agent, the curing agent may be mixed with the base resin so that the equivalent ratio of the active hydrogen groups of the crosslinking agent to the NCO group content in the base resin is 0.8 or more, 0.9 or more, or 1.0 or more. The curing agent may be mixed with the base resin so that the equivalent ratio of the active hydrogen groups of the crosslinking agent to the NCO group content in the base resin is 1.5 or less, 1.3 or less, or 1.2 or less.

[0041] 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) can be 0.8 or more, preferably 0.9 or more, and more preferably 1.0 or more, when mixing the base agent and curing agent in the mixing step. When the NCO groups / NH2 groups are within this range, discoloration due to bleeding of unreacted polyamine to the surface of the cured product is less likely to occur. The NCO groups / NH2 groups ratio can be 1.5 or less, preferably 1.3 or less, and more preferably 1.2 or less. When the NCO groups / NH2 groups are within this range, a cured product with superior tensile strength, tear strength, and tensile product can be obtained.

[0042] 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 or floor surface 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 hand application (hand coating). Hand application refers to application to the substrate by hand using a trowel, spatula, roller, brush, or the like. That is, hand coating can be performed in the mixing process. Hand application includes mechanical application using automatic mixing devices such as static mixers and dynamic mixers, as well as application using tools such as rollers, ricin guns, airless guns, and brushes. Note that this does not preclude the mixture according to this embodiment from being applied to a substrate by methods other than hand application, such as spray coating.

[0043] 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 0.1 to 10.0 mm.

[0044] 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, 45 minutes or more for the viscosity of the mixture of the base agent and the curing agent to reach 100,000 mPa·s at 23°C. In terms of pot life, it is more preferable that it takes 60 minutes or more for the viscosity of the mixture of the base agent and the curing agent to reach 100,000 mPa·s at 23°C.

[0045] 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 even as a rust preventative material, etc. Depending on the application, it is also possible to add an organic solvent such as xylene to the mixture before application depending on the workability.

[0046] Regardless of the type of substrate, it is preferable to provide a primer layer between the substrate and the coating film that exhibits adhesion to both the substrate and the coating film. For example, if the substrate is mortar, concrete, ALC, or plywood, a urethane resin primer or an epoxy resin primer is preferred, representative examples of which include HC Primer CB30 or CB30III and 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 steel sheet, copper sheet, FRP, or epoxy resin, a urethane resin primer or an epoxy resin primer is preferred, representative examples of which include Millionate MS-60 and the epoxy resin primer HC Primer EPO (manufactured by Hodogaya Construction Materials Co., Ltd.). For example, if the substrate is vinyl chloride, a urethane resin primer is preferred, representative example of which is Millionate MS-60 (manufactured by Hodogaya Construction Materials Co., Ltd.). For example, if the substrate is lead, an epoxy resin primer is preferred, representative example of which is HC Primer EPO (manufactured by Hodogaya Construction Materials Co., Ltd.). For example, if the substrate is an EPDM rubber sheet, a chloroprene-based resin primer is preferred, a representative example of which is Millionate MS-70 (manufactured by Hodogaya Construction Materials Co., Ltd.) As a primer that is considerate of the human body and the environment, an epoxy resin primer that is free of organic solvents and specific chemical substances is preferred, a representative example of which is HC Primer EPO.

[0047] The waterproofing method according to this embodiment can provide a waterproof structure comprising a substrate and a cured product (corresponding to a "coating film" or "waterproofing material") formed on the substrate. Such a waterproof structure can further comprise a top coat layer on the surface of the cured product opposite the substrate. In this case, direct sunlight can be avoided and design can be improved. For the top coat layer, it is preferable to use an acrylic urethane resin top coat, for example, a representative example of which is HC Ecotop. It is even more preferable to use an acrylic urethane resin top coat that does not contain specific chemical substances that are hazardous to the human body and the environment and does not comply with the Organic Solvent Poisoning Prevention Law. Representative examples include HC Ecotop Zero and HC Ecotop Zero Cool (manufactured by Hodogaya Construction Materials Co., Ltd.). [Example]

[0048] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0049] In the table below, the abbreviations in the table represent the following components. (1) D-700: Polyoxypropylene diol (number average molecular weight 700, product name "Actocol D-700") (2) D-1000: Polyoxypropylene diol (number average molecular weight 1000, trade name "Actocol D-1000", manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.) (3) D-1500: Polyoxypropylene diol (number average molecular weight 1500, trade name "Actocol D-1500", manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.) (4) D-2000: Polyoxypropylene diol (number average molecular weight 2000, trade name "Actocol D-2000", manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.) (5) D-3000: Polyoxypropylene diol (number average molecular weight 3000, trade name "Actocol D-3000", manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.) (6) T-400: Polyoxypropylene triol (number average molecular weight 400, trade name "Actocol T-400", manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.) (7) T-1500: Polyoxypropylene triol (number average molecular weight 1500, trade name "Actocol T-1500", manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.) (8) T-3000: Polyoxypropylene triol (number average molecular weight 3000, trade name "Actocol T-3000", manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.) (9) G-5000: Polyoxypropylene triol (number average molecular weight 5000, trade name "Hiflex G-5000", manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) (10) PTMG-250: Polytetramethylene ether glycol (number average molecular weight 189, trade name "PTMG-250", manufactured by Mitsubishi Chemical Corporation) (11) 650SN: Polytetramethylene ether glycol (number average molecular weight 650, trade name "PTG-650SN", manufactured by Hodogaya Chemical Co., Ltd.) (12) 850SN: Polytetramethylene ether glycol (number average molecular weight 850, trade name "PTG-850SN", manufactured by Hodogaya Chemical Co., Ltd.) (13) 1000SN: Polytetramethylene ether glycol (number average molecular weight 1000, trade name “PTG-1000SN”, manufactured by Hodogaya Chemical Co., Ltd.) (14)L1000: Number average molecular weight 1000, product name "PTG-L1000", manufactured by Hodogaya Chemical Industry Co., Ltd.) (15) IPDI: Isophorone diisocyanate (trade name "VESTANAT IPDI", manufactured by EVONIC) (16) MPO: 2-methyl-1,3-propanediol (manufactured by Dalian Chemical Industry Co., Ltd.) (17) 1,4-BD: 1,4-butanediol (Fujifilm Wako Pure Chemical Industries, Ltd.) (18) IP Solvent 1620: Isoparaffin solvent (manufactured by Idemitsu Kosan Co., Ltd.) (19) DINP: Diisononyl phthalate (trade name "DINP", manufactured by C.G. Ester Corporation) (20) DINA: Diisononyl adipate (trade name "DINA", manufactured by Taoka Chemical Co., Ltd.) (21) DOA: dioctyl adipate (trade name "DOA", manufactured by Taoka Chemical Co., Ltd.) (22) FLORENE AC-2000HF: surfactant (manufactured by Kyoeisha Chemical Co., Ltd.) (23) DBTDL: Dibutyltin dilaurate (trade name "Neostan U-100", manufactured by Nitto Kasei Co., Ltd.) (24) DETDA: Diethyltoluenediamine (Ethacure 100 PLUS, manufactured by Albemarle Corporation) (25) Special grade calcium carbonate: calcium carbonate (manufactured by Sankyo Seifun Co., Ltd.)

[0050] Example 1 <Preparation of the main agent> A 1-liter glass flask equipped with a stirrer, thermometer, condenser, and nitrogen seal tube was charged with 9.7 parts by weight of PTMG-250, 45.7 parts by weight of D-1000, and 8.3 parts by weight of DINA, and dehydrated under reduced pressure at 95-105°C for 1 hour. After sealing with nitrogen, the liquid was cooled to below 40°C, and 0.0025 parts by weight of DBTDL catalyst was added under a nitrogen stream and homogenized. Then, 32.4 parts by weight of IPDI was gradually added, and the mixture was heated to 70°C with stirring for 2.3 hours until the reaction was complete. After the reaction, the liquid was cooled to room temperature, and 3.9 parts by weight of IP Solvent 1620 was added as a viscosity modifier and homogenized with stirring to obtain the base resin.

[0051] <Measurement of NCO concentration of main agent> Approximately 0.3 g of the obtained base compound was weighed into a 300 ml Erlenmeyer flask and added to 15 ml of 0.2 mol / L di-n-butylamine toluene solution and dissolved and mixed. A few drops of bromophenol blue and approximately 100 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 mol / L hydrochloric acid solution titration value) × 0.1 mol / L hydrochloric acid solution factor × 0.1 × 100) ÷ (sample mass × 1000)

[0052] <Equivalent ratio in the main agent> The equivalent (eq) of the main raw material is the molecular weight per reactive group that each raw material has, and the equivalent can be calculated by dividing the amount used by the molecular weight per equivalent.

[0053] <Evaluation of low-temperature storage stability (low-temperature storage ability)> 20 g of the base agent was sealed in a 30 mL sample bottle, placed in a temperature and humidity test chamber (product name "HIFLEX NEO FX-411N", Kusumoto Chemicals Co., Ltd.), and stored at -20°C or -5°C for at least one day. The appearance of the stored base agent was observed, and it was rated as "A" if it was transparent and liquid, "B" if it was liquid but partially cloudy, "C" if it was liquid but cloudy, "D" if it was fluid but partially solidified, and "E" if it was solidified.

[0054] <Adjusting the hardener> 7.73 parts by mass of DETDA, 28.94 parts by mass of DINP, 2.11 parts by mass of additives, and 61.22 parts by mass of special grade calcium carbonate were placed in a 2 L cylindrical open-top metal container and mixed with stirring at room temperature for 60 minutes using a dissolver to obtain a curing agent.

[0055] <Preparation of coating film (cured product)> The obtained base agent and curing agent were stirred and mixed in a temperature- and humidity-controlled chamber at a room temperature of 23°C and a humidity of 50% so that the mass ratio of base agent to curing agent was 1:1. The stirred mixture obtained was applied to a release-treated substrate to a thickness of 2 mm, and then cured for 7 days in the temperature- and humidity-controlled chamber to obtain a coating film (cured product).

[0056] <Evaluation of curability of coating film (cured product)> For the mixture 16 hours after mixing the base agent and curing agent, the curing property was evaluated by touch, simulating walking on the coating film (cured product) and the next process. If it was judged that there was no problem walking on the coating film (cured product), it was given an "A", if it was judged that it was possible to walk on the coating film (cured product) while wearing rubber-soled shoes or slippers without carrying heavy objects, it was given a "B", if it was judged that it was unsuitable for walking on but possible to walk on with the use of a floor board to distribute the load, it was given a "C", and if it was judged that the coating film (cured product) had not hardened enough to withstand practical use, it was given a "D".

[0057] <Evaluation of pot life and initial viscosity of mixture> In the above-mentioned constant temperature and humidity chamber at a room temperature of 23°C and a humidity of 50%, the viscosity at the time of mixing the base resin and curing agent was measured using a rotational viscometer (Toki Sangyo Co., Ltd., BH II type) in accordance with JIS K 7301:1995 "Test method for tolylene diisocyanate prepolymers for thermosetting urethane elastomers, 6.2 Viscosity" (initial viscosity of mixture). The pot life was measured as the time from the time of mixing the base resin and curing agent until the viscosity reached 60,000 mPa·s or 100,000 mPa·s.

[0058] <Evaluation of the presence or absence of bleeding of the coating film (cured product)> If bleeding due to plasticizers or the like occurred in the coating film (cured product) obtained by mixing and applying the above-mentioned base agent and curing agent, it was judged as "present" with bleeding, and if there was no discoloration or bleeding of plasticizers or the like, it was judged as "absent" with bleeding.

[0059] <Evaluation of tensile and tear properties of coating film (cured product)> The tensile strength (Tb), elongation at break (Eb), tear strength (Tt), and tensile product (Tp) of the coating film (cured product) were measured based on JIS A 6021:2011 "Waterproof coating materials for architecture" (test temperature: 23°C).

[0060] The produced coating film (cured product) was further cured for 7 days, and then the tensile strength (Tb), elongation at break (Eb), and tensile product (Tp) were measured based on JIS A 6021:2011 "Waterproof coating material for architecture" (test temperature: 23°C).

[0061] <Evaluation of coating film (cured product) hardness> The hardness of the coating film (cured product) obtained after mixing the base resin and curing agent and curing for 7 days was measured, as well as the hardness of the coating film (cured product) after curing for another 7 days. The hardness was measured in accordance with JIS K 6253 using a Durometer Type A (manufactured by Kobunshi Keiki Co., Ltd.) or a Durometer Type D (manufactured by Ueshima Seisakusho). In the table, the hardness measured with Durometer Type A is represented as (JIS A), and the hardness measured with Durometer Type D is represented as (JIS D).

[0062] (Examples 2 to 47 and Comparative Examples 1 to 12) For Examples 2 to 47 and Comparative Examples 1 to 12, coating films (cured products) were prepared using the compositions (parts by mass) shown in Tables 1, 3, 5, 7, 9, 11, 13 and 15 in the same manner as in Example 1, and various measurements were carried out.

[0063] [Table 1]

[0064] [Table 2]

[0065] [Table 3]

[0066] [Table 4]

[0067] [Table 5]

[0068] [Table 6]

[0069] Table 7

[0070] Table 8

[0071] Table 9

[0072] Table 10

[0073] Table 11

[0074] Table 12

[0075] Table 13

[0076] Table 14

[0077] Table 15

[0078] Table 16

Claims

1. It consists of a base agent containing urethane prepolymer and a curing agent. the urethane prepolymer is a reaction product of a polyol and isophorone diisocyanate; The polyol includes polyoxypropylene polyol and polytetramethylene ether glycol; The number average molecular weight of the polytetramethylene ether glycol is 900 or less, the equivalent ratio of the total amount of isocyanate groups of the isophorone diisocyanate to the total amount of hydroxyl groups of the polyol is 1.50 to 1.

98.

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 150 to 700.

3. 3. The room-temperature curable two-component coating composition according to claim 1, wherein the polyoxypropylene polyol contains a polyoxypropylene diol.

4. A waterproofing agent comprising the room temperature curable two-component coating composition according to any one of claims 1 to 3.

5. A waterproofing method comprising the step of forming a cured product of the waterproofing agent according to claim 4 on a substrate.

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