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

Abstract

To provide a room temperature-curable two-pack coating composition having a sufficiently long pot life.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 at least polyoxyalkylene polyols (excluding polytetramethylene ether glycol) having two or more hydroxyl groups per molecule. The ratio of a polyoxyalkylene polyol having three or more hydroxyl groups per molecule out of the polyoxyalkylene polyols to the total of a polyoxyalkylene polyol (bifunctional PPG) having two hydroxyl groups per molecule and the polyoxyalkylene polyol having three or more hydroxyl groups per molecule is less than 0.16 in an equivalent ratio. The bifunctional PPG has a number average molecular weight of less than 1,500. The equivalent ratio of the total amount of isocyanate groups of isophorone diisocyanate to the total amount of hydroxyl groups of the polyol is less than 1.85.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] Polyurethane waterproof materials (coating waterproof materials) are used as waterproof materials for building roofs, verandas, corridors, etc., and are also widely used for applications such as floor coatings and elastic pavements for sports facilities. As a polyurethane waterproof material, for example, a waterproof material obtained by mixing a main agent containing an isocyanate group-terminated prepolymer with a curing agent, applying it, and curing it is known. Patent Document 1 discloses the use of an isocyanate-terminated prepolymer as the polyisocyanate in a method for producing a polyurethane coating film material in which a main agent containing a polyisocyanate as a main component and a curing agent containing an aromatic polyamine and a plasticizer are mixed and cured at room temperature.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the above-mentioned isocyanate group-terminated prepolymer is used, the reaction between the main agent and the curing agent is too fast, and it may be difficult to ensure the pot life as a hand-applied urethane rubber-based coating waterproof material.

[0005] Therefore, an object of the present invention is to provide a room temperature curing two-component coating composition having a sufficient pot life.

Means for Solving the Problems

[0006] The present invention provides a room-temperature curing two-component coating composition comprising a main component containing a urethane prepolymer and a curing agent, wherein the urethane prepolymer is a reaction product of a polyol and isophorone diisocyanate, the polyol contains at least a polyoxyalkylene polyol (excluding polytetramethylene ether glycol) having 2 or more hydroxyl groups per molecule, the ratio of polyoxyalkylene polyols with 3 or more hydroxyl groups per molecule to the sum of polyoxyalkylene polyols with 2 and polyoxyalkylene polyols with 3 or more hydroxyl groups per molecule is less than 0.16 in terms of equivalent weight, the number-average molecular weight of polyoxyalkylene polyols with 2 hydroxyl groups per molecule is less than 1500, and the equivalent weight ratio of the total amount of isocyanate groups of the isophorone diisocyanate to the total amount of hydroxyl groups of the polyol is less than 1.85. Here, "room-temperature curing type" means curing at ambient temperature (e.g., 0°C to 45°C) without the application of external heat. Such room-temperature curing two-component coating compositions have a sufficiently long pot life.

[0007] The present invention also provides a waterproofing agent comprising the above-mentioned room-temperature curing two-component coating composition. Such a waterproofing agent has a sufficiently long pot life.

[0008] 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]

[0009] According to the present invention, it is possible to provide a room-temperature curing two-component coating composition having a sufficiently long pot life. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below. However, the present invention is not limited to the following embodiments.

[0011] In this invention, the number-average molecular weight refers to the value measured using gel permeation chromatography (GPC) with polystyrene as the standard substance, and can be measured under the following conditions. Equipment: TOSOH HCL-8320 (manufactured by Tosoh Corporation) Column: TSKgel G4000H + G2500H (7.5mm I.D x 30cm) (Manufactured by Tosoh Corporation) Detector: RI Eluent:THF Injection volume: 100μL Flow rate: 1.0mL / min Measurement temperature: 40℃ Sample concentration: 0.3 wt / vol%

[0012] The urethane prepolymer is a reaction product of a polyol and isophorone diisocyanate. The polyol contains at least one polyoxyalkylene polyol (excluding polytetramethylene ether glycol) with two or more hydroxyl groups per molecule. The ratio of polyoxyalkylene polyols with three or more hydroxyl groups per molecule to the sum of polyoxyalkylene polyols with two and polyoxyalkylene polyols with three or more hydroxyl groups per molecule is less than 0.16 in terms of equivalent weight. The number-average molecular weight of polyoxyalkylene polyols with two hydroxyl groups per molecule is less than 1500. The equivalent weight ratio of the total amount of isocyanate groups of the isophorone diisocyanate to the total amount of hydroxyl groups of the polyol is less than 1.85.

[0013] Polyoxyalkylene polyols (excluding polytetramethylene ether glycol) having two or more hydroxyl groups per molecule (hereinafter also simply referred to as "polyoxyalkylene polyols") can have a number-average molecular weight of 300 or more, preferably 400 or more, and more preferably 500 or more. When the number-average molecular weight of the polyoxyalkylene polyol is within this range, the elongation at fracture of the cured product obtained by curing the mixture of the main agent and the curing agent is improved. The number-average molecular weight of the polyoxyalkylene polyol can be 6000 or less, preferably 5000 or less, and more preferably 4000 or less. When the number-average molecular weight of the polyoxyalkylene polyol is within this range, the tensile strength, tensile product, and tear strength of the cured product obtained by curing the mixture of the main agent and the curing agent are further improved. The number-average molecular weight of polyoxyalkylene polyols with two hydroxyl groups per molecule is less than 1500.

[0014] Among polyoxyalkylene polyols, the ratio of polyoxyalkylene polyols with 3 or more hydroxyl groups per molecule to the total of polyoxyalkylene polyols with 2 hydroxyl groups per molecule and polyoxyalkylene polyols with 3 or more hydroxyl groups per molecule is less than 0.16 in equivalent weight, and can be 0.15 or less, or 0.14 or less. Among the above polyoxyalkylene polyols, the ratio of polyoxyalkylene polyols with 3 or more hydroxyl groups per molecule to the total of polyoxyalkylene polyols with 2 hydroxyl groups per molecule and polyoxyalkylene polyols with 3 or more hydroxyl groups per molecule can be 0 or more, 0.025 or more, or 0.05 or more in equivalent weight. When the ratio of polyoxyalkylene polyols with 3 or more hydroxyl groups per molecule to the total of polyoxyalkylene polyols with 2 hydroxyl groups per molecule and polyoxyalkylene polyols with 3 or more hydroxyl groups per molecule is within the above range, the pot life is longer.

[0015] Polyoxyalkylene polyols can be 2-6 functional. Here, 2-6 functional means having 2-6 hydroxyl groups in one molecule. These polyoxyalkylene polyols are preferably 2-3 functional, and only bifunctional polyols (e.g., polyoxyethylenediol, polyoxypropylenediol, ethylene oxide adduct of polyoxypropylenediol, etc.) can be used. Alternatively, a mixture of bifunctional polyoxyalkylene polyols (e.g., polyoxyethylenediol, polyoxypropylenediol, ethylene oxide adduct of polyoxypropylenediol, etc.) and trifunctional polyoxyalkylene polyols (e.g., polyoxypropylenetriol, ethylene oxide adduct of polyoxypropylenetriol, etc.) can be used. The molecular shape may be linear or branched.

[0016] The polyol does not contain polytetramethylene ether glycol and may contain other polyol components besides polyoxyalkylene polyols. Other polyol components may include, for example, polyhydric alcohols having 2 to 20 carbon atoms, polyoxyalkylene polyols (excluding the PTMG and polyoxyalkylene polyols mentioned above) obtained by adding an alkylene oxide with 2 to 4 carbon atoms to a polyhydric alcohol having 2 to 20 carbon atoms or a polyhydric phenol 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.

[0017] The equivalent ratio (NCO group / OH group) of the total isocyanate groups (NCO groups) of IPDI to the total hydroxyl groups (OH groups) of the polyol is 1.66 or higher, and can be 1.68 or higher. When the NCO group / OH group is within this range, a viscosity that facilitates handling of the main component can be obtained. The NCO group / OH group ratio is less than 1.85, and can be 1.75 or lower, or 1.70 or lower. When the NCO group / OH group is within this range, a longer pot life can be obtained.

[0018] 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 main agent 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 pot life can be kept long, and the cost also tends to be suppressed.

[0019] The urethane prepolymer can be obtained, for example, by adding IPDI to a polyol in a predetermined equivalent ratio and reacting them by heating and mixing.

[0020] 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 it can be, for example, 30°C or higher.

[0021] The reaction time of the polyol and IPDI can be 0.5 to 7 hours.

[0022] A catalyst may be mixed simultaneously with or before or after the mixing of the polyol and IPDI. As the catalyst, for example, urethanization catalysts (urethane reaction accelerators) such as organic acids, organic acid metal salts, acid anhydrides, and imidazole compounds can be used. Examples of organic acids include propionic acid, 2-methylpentanoic acid, isononanoic acid, 2-ethylhexanoic acid, neodecanoic acid, naphthenic acid, oleic acid, linoleic acid, linolenic acid, etc. Examples of organic acid metal salts include zinc salts, bismuth salts, magnesium salts, zirconium salts, calcium salts, barium salts, copper salts, etc. As the catalyst, it is preferable to use tin salts such as dibutyltin dilaurate and dioctyltin laurate.

[0023] The main component may further contain, in addition to the urethane prepolymer, a plasticizer, solvent, or other viscosity modifier to adjust the viscosity when the main component and the curing agent described later are mixed. The main component may further contain a catalyst and / or retarder to efficiently react the isocyanate group of IPDI with the hydroxyl group of the polyol. The main component may contain additives to improve the finish, durability, and adhesion to other materials of the cured product obtained when the mixture of the main component and the curing agent hardens.

[0024] Plasticizers that may be included in the main component include cyclohexane derivatives (1,2-cyclohexanedicarboxylate diisononyl ester (DHIN), 1,2-cyclohexanedicarboxylate bis(2-ethylhexyl) (DHEH), etc.), aliphatic dichlorate esters (diisononyl adipate (DINA)), terephthalate diester (DOTP), phosphate esters, trimellitic acid esters, sebacate acid esters, epoxy fatty acid esters, glycol esters, animal oil-based fatty acid esters, petroleum / mineral oil-based plasticizers, alkylene oxide polymerization-based plasticizers, phthalate diesters (di-2-ethylhexyl phthalate (DOP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), din-normal octyl phthalate (DNOP)), etc.). When phthalate diesters are not used as plasticizers, a safer, room-temperature curing two-component coating composition that is more considerate of human health and the environment can be obtained.

[0025] The total content of the plasticizers, solvents, catalysts, retarders, additives, etc. mentioned above can be 0 to 25% by mass, or 0 to 20% by mass, based on the total mass of the main component.

[0026] The viscosity of the main component 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 6000 mPa·s or higher. When the viscosity of the main component is within this range, it becomes easier to ensure a consistent film thickness of the cured product (coating film). The viscosity of the main component at 23°C can be 20000 mPa·s or lower, preferably 18000 mPa·s or lower, and more preferably 15000 mPa·s or lower. When the viscosity of the main component is within this range, the main component becomes easier to handle, and as a result, the mixture of the main component and curing agent becomes easier to apply. The viscosity of the main component can be measured using a rotational viscometer in accordance with "Test method for tolylene diisocyanate type prepolymer for thermosetting urethane elastomers 6.2 Viscosity" in JIS K 7301:1995.

[0027] The curing agent may contain hydroxyl compounds such as polyhydric alcohols and crosslinking agents such as polyamines. 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, and 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'-disecondary butyl-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-butyl4,4'-methylenebis(cyclohexylamine), isophoronediamine, norbornenediamine, N,N'-(dicyclohexylmethane4,4'-diyl)-bisaspartate tetraethyl ester, ethylenediamine, trimethylenediamine, triethylenetetramine, diethylenetriamine, triaminopropane, 2,2,4-trimethylhexamethylenediamine, 2-hydroxyethylethylenediamine, N,Aliphatic polyamines such as N'-(2-methylpentane-1,5-diyl)-bisaspartate tetraethyl ester, polyoxyalkyleneamines, and polyetheramines can be used. These crosslinking agents can be used individually 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 included as a crosslinking agent, its high safety means there are no restrictions on its manufacture or use.

[0028] The amount of crosslinking agent contained in the curing agent, based on the total mass of the curing agent, can be 1 to 10% by mass, or 2 to 8% by mass.

[0029] In addition to the crosslinking agent, the hardening agent may further contain 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 dioxide; and additives such as wetting agents, dispersants, anti-settling agents, light stabilizers, defoaming agents, surface modifiers, adhesion enhancers, and weather-resistant enhancers. 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.

[0030] By mixing the main agent and hardener described above, the mixture hardens, and a coating film (also referred to as "waterproofing material"; the same applies hereinafter) can be obtained. The waterproofing agent according to this embodiment exhibits excellent tensile strength, tear strength, tensile strength, and elongation at break, and can form a high-strength and highly elongated coating film. Furthermore, the coating film obtained with the waterproofing agent according to this embodiment is safe for human health and the environment.

[0031] The waterproofing method according to this embodiment includes a step of forming a cured product of the waterproofing agent described above on a substrate. This waterproofing method may also include a mixing step of mixing the main component and the hardening agent of the waterproofing agent, and a coating step of applying the mixture onto the substrate in order to form a cured product (corresponding to a "coating film" or "waterproofing material").

[0032] In the mixing process, the temperature (ambient temperature) when mixing the main component and the hardener can be, for example, -5 to 45°C.

[0033] The mixing ratio of the main component and the hardener can be 1:1 to 4 by mass, preferably 1:1 to 3, and more preferably 1:1.

[0034] If the curing agent contains a crosslinking agent, the curing agent may be mixed with the main component such that the equivalent ratio of the active hydrogen groups of the crosslinking agent to the NCO group content in the main component is 0.8 or higher, 0.9 or higher, or 1.0 or higher. The curing agent may be mixed with the main component such that the equivalent ratio of the active hydrogen groups of the crosslinking agent to the NCO group content in the main component is 1.5 or lower, 1.3 or lower, or 1.2 or lower.

[0035] When the curing agent contains polyamine, the equivalent ratio of NCO groups in the main component to amino groups (NH2 groups) in the curing agent (NCO group / NH2 group) can be set to 0.8 or higher, preferably 0.9 or higher, and more preferably 1.0 or higher. When the NCO group / NH2 group is within this range, discoloration due to unreacted polyamine bleeding onto the surface of the cured product is less likely to occur. The NCO group / NH2 group can be set to 1.5 or lower, preferably 1.3 or lower, and more preferably 1.2 or lower. When the NCO group / NH2 group is within this range, a cured product with superior tensile strength, tear strength, and tensile strength can be obtained.

[0036] In the coating process, the mixture of the main agent and the hardener is applied to the substrate before it hardens. The substrate is not particularly limited and can be the walls, floors, etc., of a house or building. The mixture of the main agent and the hardener according to this embodiment can also have a sufficient pot life, and in this case, it is particularly suitable for application by hand (hand coating). Hand coating means applying it to the substrate by hand using a trowel, spatula, roller, brush, etc. In other words, hand coating can be performed in the mixing process. Hand coating includes application by machine, such as automatic mixing devices such as static mixers and dynamic mixers, and application using tools such as rollers, resin guns, airless guns, and brushes. It should be noted that there is no prejudice to applying the mixture according to this embodiment to the substrate by methods other than hand coating, such as by spraying (spray coating).

[0037] A mixture of the main agent and the hardener can be applied to the substrate so that the thickness of the hardened product obtained from the hardening of this mixture is 0.1 to 10.0 mm.

[0038] According to the room-temperature curing two-component coating composition of this embodiment, for example, it takes 50 minutes or more for the viscosity of the mixture of the main agent and the curing agent to reach 60,000 mPa·s at 23°C, so it can be said that a sufficiently long pot life can be obtained. In the room-temperature curing two-component coating composition of this embodiment, it is more preferable in terms of pot life if it takes 55 minutes or more for the viscosity of the mixture of the main agent and the curing agent to reach 60,000 mPa·s at 23°C.

[0039] Traditionally, increasing the pot life sometimes resulted in a longer time required for the tensile strength and other strengths to fully develop after applying the mixture of the main agent and hardener. Specifically, this was due to the high-strength and high-elongation standards for tensile performance (tensile strength (Tb) of 10 N / mm²) as defined in JIS A 6021:2011 "Waterproof coatings for buildings". 2In the previous case, it sometimes took more than 7 days to satisfy the following criteria: elongation at break (Eb) of 450% or more, tear strength (Tt) of 30 N / mm or more, and tensile product (Tp) of 700 N / mm or more. On the other hand, the cured product of the room-temperature curing two-component coating composition according to this embodiment can satisfy both the above-mentioned high-strength and high-elongation criteria within 7 days after application of the mixture of the main agent and the curing agent.

[0040] The waterproofing material obtained by the method described above can be used not only as a waterproofing material, but also as flooring material for sports facilities and other structures requiring high strength and load-bearing capacity, as well as as a covering material for buildings and other structures, and as a rust preventative. Depending on the application, it may also be possible to add an organic solvent such as xylene to the mixture before application, depending on the workability.

[0041] 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, with HC Primer CB30 or CB30III and HC Primer EPO (manufactured by Hodogaya Building Materials Co., Ltd.) being typical examples. For example, if the substrate is stone, glass, porcelain tile, iron, aluminum, stainless steel, galvanized iron sheet, copper sheet, FRP, or epoxy resin, a urethane resin primer or an epoxy resin primer is preferred, with MS-60 and HC Primer EPO (manufactured by Hodogaya Building Materials Co., Ltd.), which is an epoxy resin primer, being typical examples. For example, if the substrate is polyvinyl chloride, it is preferable to use a urethane resin primer, with Millionate MS-60 (manufactured by Hodogaya Building Materials Co., Ltd.) being a typical example. For example, if the substrate is lead, it is preferable to use an epoxy resin primer, with HC Primer EPO (manufactured by Hodogaya Building Materials Co., Ltd.) being a typical example. For example, if the substrate is an EPDM rubber sheet, a chloroprene-based resin primer is preferred, and a typical example is Millionate MS-70 (manufactured by Hodogaya Building Materials Co., Ltd.). As a primer that is considerate of human health and the environment, an epoxy resin primer that is free of organic solvents and specific chemical substances is preferred, and a typical example is HC Primer EPO.

[0042] The waterproofing method according to this embodiment provides a waterproof structure comprising a base material and a cured product (corresponding to a "coating film" or "waterproofing material") formed on the base material. Such a waterproof structure may further include a topcoat layer on the surface of the cured product opposite the base material. In this case, direct sunlight can be avoided and the aesthetic appeal can be improved. For the topcoat layer, it is preferable to use an acrylic urethane resin topcoat, for example, HC Eco Top. It is even more preferable to use an acrylic urethane resin topcoat that does not contain specific chemical substances that take into consideration the impact on human health and the environment, and does not comply with the Organic Solvent Poisoning Prevention Act. Representative examples include HC Eco Top Zero and HC Eco Top Zero Cool (manufactured by Hodogaya Building Materials Co., Ltd.). [Examples]

[0043] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0044] In the table below, the abbreviations in the table indicate the following components. (1) PPG-D700: Polypropylene glycol (number average molecular weight 700, trade name "Actcol D-700", manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) (2) PPG-D1000: Polypropylene glycol (number average molecular weight 1000, trade name "Actcol D-1000", manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) (3) PPG-D2000: Polypropylene glycol (number average molecular weight 2000, trade name "Actcall D-2000", manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) (4) PPG-T400: Polypropylene glycol (number average molecular weight 400, trade name "Actcol T-400", manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) (5) PPG-T1500: Polypropylene glycol (number average molecular weight 1500, trade name "Actcol T-1500", manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) (6) PPG-T3000: Polypropylene glycol (number average molecular weight 3000, trade name "Actcall T-3000", manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.) (7) PPG-T5000: Polypropylene glycol (number average molecular weight 5000, trade name "Hyflex G-5000", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (8) BPX-33: Bisphenol A propylene oxide adduct (number average molecular weight, trade name "ADEKA Polyether BPX-33", manufactured by ADEKA Corporation) (9) IPDI: Isophorone diisocyanate (product name "VESTANAT IPDI", manufactured by EVONIC) (10) MPO: 2-methyl-1,3-propanediol (manufactured by Dalian Chemical Industry Co., Ltd.) (11) IP Solvent 1620: Isoparaffinic solvent (manufactured by Idemitsu Kosan Co., Ltd.) (12) DINP: Diisononyl phthalate (product name "DINP", manufactured by CG Ester Co., Ltd.) (13) DINA: Diisononyl adipate (product name "DINA", manufactured by Taoka Chemical Industry Co., Ltd.) (14) DBTDL: Dibutyltin dilaurate (product name "Neostan U-100", manufactured by Nitto Kasei Co., Ltd.) (15) DETDA: Diethyltoluenediamine ("Etacure PLUS", manufactured by Albemarle Corporation) (16) Special Grade Calcium Carbonate: Calcium carbonate (manufactured by Sankyo Flour Milling Co., Ltd.)

[0045] (Example 1) <Preparation of the main ingredient> In a 1-liter glass coruben equipped with a stirrer, thermometer, condenser, and nitrogen sealing tube, 20.0 parts by mass of PPG-D700, 42.3 parts by mass of PPG-D1000, and 3.8 parts by mass of DINA were charged, and dehydration was carried out under reduced pressure at 95-105°C for 1 hour. After nitrogen sealing, the liquid was cooled to below 40°C, and 0.0025 parts by mass of DBTDL, the catalyst, was added and homogenized under a nitrogen stream. Then, 26.3 parts by mass of IPDI was gradually added, and the mixture was heated at 70°C for 3.5 hours with stirring until the reaction was complete. The liquid after the reaction was cooled to room temperature, and 7.5 parts by mass of IP Solvent 1620 was added as a viscosity modifier and homogenized with stirring to obtain the main component.

[0046] <Measurement of NCO concentration of the main ingredient> Approximately 0.3 g of the main component obtained was weighed into a 300 ml Erlenmeyer flask and dissolved and mixed with 15 ml of 0.2 mol / L di-n-butylamine toluene solution. 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)

[0047] <Equivalent ratio of the main ingredient> The equivalent weight (eq) of the main ingredient is the molecular weight per reactive group in each ingredient. The equivalent weight is calculated by dividing the amount used by the molecular weight per equivalent.

[0048] <Evaluation of low-temperature storage stability (low-temperature storage capability)> 20g of the main component was sealed in a 30mL sample bottle and stored in a temperature and humidity test chamber (product name "HIFLEX NEO FX-411N", Kusumoto Kasei Co., Ltd.) at -20°C for at least one day. The appearance of the stored main component was observed and judged as follows: "A" if transparent and liquid, "B" if partially cloudy but liquid, "C" if liquid but cloudy, "D" if fluid but partially solidified, and "E" if solidified.

[0049] <Preparation of the hardening agent> 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 2L cylindrical metal container with an open top, and stirred and mixed at room temperature in a dissolver for 60 minutes to obtain a curing agent.

[0050] <Preparation of coating film (cured product)> The obtained main component and hardener were stirred and mixed in a constant temperature and humidity chamber at room temperature of 23°C and humidity of 50% so that the mass ratio of main component to hardener was 1:1. The resulting stirred mixture was applied to the stripped substrate to a thickness of 2 mm, and then cured in the aforementioned constant temperature and humidity chamber for 7 days to obtain a coating film (cured product).

[0051] <Evaluation of the curability of coating films (cured products)> For the mixture 16 hours after mixing the main agent and the hardener, the hardness was evaluated by touch, simulating walking on the coating (cured product) and subsequent work processes. "A" was used when it was determined that there was no impediment to walking on the coating (cured product), "B" was used when it was determined that it was possible to walk on the coating (cured product) while wearing rubber-soled shoes or slippers without carrying heavy objects, "C" was used when it was determined that it was unsuitable for walking but possible with the use of load-distributing mats, etc., and "D" was used when it was determined that the hardening of the coating (cured product) was not suitable for practical use.

[0052] <Evaluation of pot life and initial mixing viscosity> In the aforementioned constant temperature and humidity chamber at a room temperature of 23°C and humidity of 50%, the viscosity at the time of mixing the main component 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 type prepolymer for thermosetting urethane elastomers 6.2 Viscosity". (Initial viscosity of mixing) In addition, the time from the time of mixing the main component and curing agent until the viscosity reached 20,000 mPa·s, 60,000 mPa·s, or 100,000 mPa·s was measured as the pot life.

[0053] <Evaluation of whether or not bleeding occurs in the coating (cured product)> If bleeding due to plasticizers, etc., occurs in the coating film (cured product) obtained by mixing and applying the above-mentioned main agent and hardener, it was judged as "bleeding present." If there was no discoloration or bleeding of plasticizers, etc., it was judged as "no bleeding."

[0054] <Evaluation of tensile and tear performance of coating films (cured products)> The tensile strength (Tb), elongation at break (Eb), tear strength (Tt), and tensile product (Tp) of the coating film (cured product) were measured according to JIS A 6021:2011 "Waterproof coating materials for buildings" (test temperature: 23°C). Here, tensile stress is the stress when the coating film (cured product) is subjected to a specified elongation.

[0055] After curing the manufactured coating film (cured product) for a further 7 days, the tensile strength (Tb), elongation at break (Eb), and tensile product (Tp) were measured according to JIS A 6021:2011 "Waterproof coating materials for buildings" (test temperature: 23°C).

[0056] <Hardness evaluation of coating film (cured product)> The hardness of the coating film (cured product) obtained by curing for 7 days after mixing the main agent and the hardener, and the hardness of the coating film (cured product) after curing for another 7 days were measured. Hardness was measured according to JIS K 6253 using a durometer type A (manufactured by Polymer Instruments Co., Ltd.) or a durometer type D (manufactured by Ueshima Seisakusho). In the table, hardness measured with durometer type A is represented as (JIS A), and hardness measured with durometer type D is represented as (JIS D).

[0057] (Examples 2-11 and Comparative Examples 1-7) For Examples 2-11 and Comparative Examples 1-7, coating films (cured products) were prepared using the same procedure as in Example 1, with the compositions (parts by mass) shown in Tables 1-3, and various measurements were performed.

[0058] [Table 1]

[0059] Table 2

[0060] Table 3

Claims

1. It consists of a main component containing a urethane prepolymer and a hardening agent. The aforementioned urethane prepolymer is a reaction product of a polyol and isophorone diisocyanate. The polyol contains at least one polyoxyalkylene polyol (excluding polytetramethylene ether glycol) having two or more hydroxyl groups per molecule, and the ratio of polyoxyalkylene polyols having three or more hydroxyl groups per molecule to the sum of polyoxyalkylene polyols having two or more hydroxyl groups per molecule and polyoxyalkylene polyols having three or more hydroxyl groups per molecule is less than 0.16 in terms of equivalent weight. The number-average molecular weight of the polyoxyalkylene polyols with two hydroxyl groups per molecule is 1000 or less. A room-temperature curing two-component coating composition, wherein 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 less than 1.

85.

2. A waterproofing agent comprising the room-temperature curing two-component coating composition described in claim 1.

3. A waterproofing method comprising the step of forming a cured product of the waterproofing agent described in claim 2 on a substrate.

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