Set of base agent and hardener, waterproofing material, and application method thereof

Abstract

To provide a set of a main agent and a curing agent that makes it possible to obtain a waterproof material having excellent tensile strength, tear strength, and tensile products, and to ensure sufficient work life during application.SOLUTION: There is provided a set that has a main agent containing an isocyanate group terminal prepolymer and a curing agent. The isocyanate group terminal prepolymer is a reactant between a polyol containing a polypropyleneglycol and a polyetherglycol having a constitutional unit represented by formula (1) and an alicyclic polyisocyanate, the polypropyleneglycol having a number average molecular weight of less than 2000 and the polyetherglycol having a number average molecular weight of less than 2000.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a set of a base agent and a hardener, a waterproofing material, and a method for applying the same. [Background technology]

[0002] Polyurethane waterproofing materials (coated waterproofing materials) are used as waterproofing materials for rooftops, verandas, corridors, etc. of buildings, and are also widely used for applications such as coated flooring and elastic paving for sports facilities. For example, a waterproofing material obtained by mixing a base material containing an isocyanate-terminated prepolymer with a curing agent, coating, and curing is known as a polyurethane waterproofing material. Patent Document 1 discloses a method for producing a room temperature curing type fast curing polyurethane coated waterproofing material, which comprises mixing a base material containing an isocyanate-terminated prepolymer obtained by reacting a polyol containing polyoxypropylene polyol and / or polyoxyethylene propylene polyol as the main raw material with tolylene diisocyanate, and a predetermined curing agent, and coating 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] The physical properties of architectural coating waterproofing materials such as polyurethane coating waterproofing materials are stipulated in the Japanese Industrial Standards (JIS), but in recent years, there has been a demand for stronger coating waterproofing materials, and the JIS standards have been revised. In addition, the raw materials for waterproofing materials that are expected to be applied by hand (including by machine) are also required to have a suitable working life to ensure sufficient construction time.

[0005] Therefore, the present invention aims to provide a set including a base agent and a hardener, which can provide a waterproofing material excellent in tensile strength, tear strength, and tensile product, and can provide a sufficient pot life during construction. Another aim of the present invention is to provide a waterproofing material using the set, and a construction method thereof. [Means for solving the problem]

[0006] The present invention provides, as a first aspect, a set comprising a base agent containing an isocyanate-terminated prepolymer and a curing agent, wherein the isocyanate-terminated prepolymer is a reaction product of an alicyclic polyisocyanate and a polyol containing polypropylene glycol and a polyether glycol having a structural unit represented by the following formula (1), wherein the polypropylene glycol has a number average molecular weight of less than 2,000 and the polyether glycol has a number average molecular weight of less than 2,000: [ka]

[0007] In the first embodiment, the cycloaliphatic polyisocyanate is preferably isophorone diisocyanate.

[0008] In a second aspect, the present invention provides a waterproofing material comprising a cured product of the mixture of the base agent and the curing agent in the above set.

[0009] In a third aspect, the present invention provides a method for applying a waterproofing material, comprising the steps of obtaining a mixture of the base agent and the curing agent in the above-mentioned set, and applying the mixture onto an object to be coated. Effect of the Invention

[0010] According to the present invention, it is possible to provide a set including a base agent and a hardener, which can provide a waterproofing material excellent in tensile strength, tear strength, and tensile product, and can provide a sufficient pot life during construction. Furthermore, according to the present invention, it is possible to provide a waterproofing material using the set, and a construction method thereof. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described, however, the present invention is not limited to the following embodiment.

[0012] In the present invention, the number average molecular weight (Mn) means 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 (7.5mm ID x 30cm) (Manufactured by Tosoh Corporation) Detector: RI Eluent:THF Injection volume: 100μL Flow rate: 1.0mL / min Measurement temperature: 40℃ Sample concentration: 0.3wt / vol%

[0013] The set according to one embodiment includes a base material containing an isocyanate-terminated prepolymer and a curing agent. The set is suitable for use as a set for producing a polyurethane waterproof material (a waterproof material set).

[0014] <Main ingredient> The base material contains an isocyanate-terminated prepolymer. The isocyanate-terminated prepolymer may be a reaction product of a polyol containing polypropylene glycol and a polyether glycol having a structural unit represented by the following formula (1), and an alicyclic polyisocyanate. [ka]

[0015] The polyol contains polypropylene glycol (hereinafter also referred to as "PPG"). The number average molecular weight of the PPG is less than 2000, preferably 1800 or less, 1600 or less, 1500 or less, less than 1500, 1400 or less, 1300 or less, 1200 or less, 1100 or less, or 1000 or less, from the viewpoint of extending the usable time during application and improving the elongation rate at break of the waterproofing material. The number average molecular weight of the PPG may be, for example, 400 or more, 600 or more, 700 or more, 800 or more, 900 or more, or 1000 or more. The number average molecular weight of the PPG is most preferably 1000.

[0016] The content of PPG in the polyol is preferably 5 equivalent % or more, 10 equivalent % or more, 20 equivalent % or more, 25 equivalent % or more, 50 equivalent % or more, or 65 equivalent % or more based on the total amount of polyol (chemical equivalent) from the viewpoint of extending the pot life during application and improving the elongation at break of the waterproofing material. The content of PPG is preferably 95 equivalent % or less, more preferably 90 equivalent % or less, and even more preferably 85 equivalent % or less, from the viewpoint of obtaining a coating film with excellent physical properties.

[0017] The polyol further contains a polyether glycol having a structural unit represented by the above formula (1). From the viewpoint of obtaining a waterproofing material having even more excellent tensile strength, tear strength, and tensile product, the number average molecular weight of the polyether glycol is less than 2000, and is preferably 1800 or less, 1600 or less, 1500 or less, 1300 or less, 1200 or less, 1100 or less, or 1000 or less. The number average molecular weight of the polyether glycol may be, for example, 250 or more, 650 or more, 850 or more, or 900 or more. The number average molecular weight of the polyether glycol is most preferably 1000.

[0018] In one embodiment, the polyether glycol is polytetramethylene ether glycol (hereinafter also referred to as "PTMG") consisting only of structural units represented by the above formula (1) and having hydroxyl groups (OH groups) at both ends.

[0019] When the polyether glycol is PTMG, from the viewpoint of obtaining a waterproof material further excellent in tensile strength, tear strength, and tensile product, the number average molecular weight of PTMG is less than 2000, and is preferably 1800 or less, 1600 or less, 1500 or less, 1400 or less, 1300 or less, 1200 or less, 1100 or less, or 1000 or less. The number average molecular weight of PTMG may be, for example, 250 or more, 650 or more, 850 or more, or 900 or more.

[0020] PTMG can be obtained by ring-opening polymerization of tetrahydrofuran (THF). Commercially available PTMG may be used.

[0021] When the polyol contains PTMG as a polyether glycol, the content of PTMG is preferably 5 equivalent% or more, 10 equivalent% or more, 20 equivalent% or more, 25 equivalent% or more, 50 equivalent% or more, or 65 equivalent% or more based on the total amount of polyol (chemical equivalent), from the viewpoint of obtaining a waterproofing material having even better tensile strength, tear strength, and tensile product. The content of PTMG is preferably 95 equivalent% or less, 90 equivalent% or less, more preferably 85 equivalent% or less, 80 equivalent% or less, or 75 equivalent% or less based on the total amount of polyol, from the viewpoint of making the viscosity of the base agent easy to handle.

[0022] In another embodiment, the polyether glycol is a copolymer having a structural unit represented by the above formula (1) and a structural unit represented by the following formula (2) (hereinafter also referred to as "copolymer A"). Copolymer A has hydroxyl groups at both ends. Copolymer A preferably has only the structural unit represented by formula (1) and the structural unit represented by formula (2). Copolymer A may be a random copolymer. [ka]

[0023] In formula (2), R 1 and R 2 One of them represents a methyl group and the other represents a hydrogen atom. That is, R 1 is a methyl group and R2 may be a hydrogen atom, R 1 is a hydrogen atom and R 2 may be a methyl group. 1 and R 2 The combinations may be the same or different.

[0024] In copolymer A, the content of the structural unit represented by formula (1) is, from an economical viewpoint, preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, based on the total amount of structural units in copolymer A. From the viewpoint of lowering the freezing point of copolymer A, the content of the structural unit represented by formula (1) is preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less.

[0025] In copolymer A, the content of the structural unit represented by formula (2) is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more, based on the total amount of structural units of copolymer A, from the viewpoint of lowering the freezing point of copolymer A. From an economic viewpoint, the content of the structural unit represented by formula (2) is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on the total amount of structural units of copolymer A.

[0026] From the viewpoint of obtaining a waterproofing material having even more excellent tensile strength, tear strength, and tensile product, the number average molecular weight of copolymer A is less than 2000, and is preferably 1800 or less, 1600 or less, 1500 or less, 1300 or less, 1200 or less, 1100 or less, or 1000 or less. The number average molecular weight of the copolymer may be, for example, 250 or more, 650 or more, 850 or more, or 900 or more.

[0027] Copolymer A can be obtained by ring-opening polymerization of tetrahydrofuran and methyltetrahydrofuran (including 2-methyltetrahydrofuran and 3-methyltetrahydrofuran). As copolymer A, a commercially available product may be used.

[0028] When the polyol contains copolymer A as a polyether glycol, the content of copolymer A is preferably 5 equivalent% or more, 10 equivalent% or more, 20 equivalent% or more, 25 equivalent% or more, 50 equivalent% or more, or 65 equivalent% or more based on the total amount of polyol (chemical equivalent) from the viewpoint of obtaining a waterproofing material further superior in tensile strength, tear strength, and tensile product. The content of copolymer A is 95 equivalent% or less, 90 equivalent% or less, 85 equivalent% or less, 80 equivalent% or less, or 75 equivalent% or less based on the total amount of polyol from an economic viewpoint.

[0029] The polyol may contain either PTMG or copolymer A, or may contain both.

[0030] The content of polyether glycol (including both PTMG and copolymer A) in the polyol is preferably 5 equivalent % or more, 10 equivalent % or more, 20 equivalent % or more, 25 equivalent % or more, 50 equivalent % or more, or 65 equivalent % or more based on the total amount of polyol (chemical equivalent) from the viewpoint of obtaining a waterproofing material further superior in tensile strength, tear strength, and tensile product. The content of polyether glycol is preferably 90 equivalent % or less, 85 equivalent % or less, 80 equivalent % or less, or 75 equivalent % or less based on the total amount of polyol from the viewpoint of extending the usable life during application.

[0031] The polyol may contain other polyol components in addition to polyether glycol and polypropylene glycol. The other polyol components may be, for example, polyhydric alcohols having 2 to 20 carbon atoms, polyoxyalkylene polyols (excluding the above-mentioned PPG, PTMG, and copolymer A) 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 (polybutadiene polyols, etc.), hydrogenated polydiene polyols, acrylic polyols, natural oil polyols (castor oil, etc.), or modified natural oil polyols.

[0032] The alicyclic polyisocyanate is not particularly limited as long as it is a compound having two or more isocyanate groups in the molecule. Examples of the alicyclic polyisocyanate include isophorone diisocyanate, dicyclohexylmethane diisocyanate, norbornene methane diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, and 1,4-bis(isocyanatomethyl)cyclohexane. The alicyclic polyisocyanate in the present invention also includes modified alicyclic polyisocyanates. Examples of modified alicyclic polyisocyanates include modified alicyclic polyisocyanates containing a urethane group, a carbodiimide group, an allophanate group, a urea group, a biuret group, a uretdione group, a uretoimine group, an isocyanurate group, or an oxazolidone group. The alicyclic polyisocyanate may be used alone or in combination of two or more of these. By using an alicyclic polyisocyanate as the polyisocyanate, the pot life during application can be sufficiently extended.

[0033] The alicyclic polyisocyanate is preferably a alicyclic diisocyanate, more preferably isophorone diisocyanate.

[0034] The isocyanate-terminated prepolymer is a reaction product of the above-mentioned polyol and alicyclic polyisocyanate. The isocyanate-terminated prepolymer can be obtained, for example, by adding the alicyclic polyisocyanate to the polyol in a predetermined equivalent ratio and reacting them by heating and mixing.

[0035] When the polyol and the alicyclic polyisocyanate are mixed, the equivalent ratio (NCO group / OH group) of the isocyanate group (NCO group) in the alicyclic polyisocyanate to the hydroxyl group (OH group) in the polyol may be 1.4 or more, 1.5 or more, or 1.6 or more, and may be 2.2 or less, 2.0 or less, or 1.8 or less.

[0036] The reaction temperature of the polyol and the alicyclic polyisocyanate may be 100° C. or lower, 90° C. or lower, or 80° C. or lower. The lower limit of the reaction temperature is not particularly limited, but is, for example, 30° C. or higher.

[0037] The content of isocyanate groups in the isocyanate group-terminated prepolymer may be 1 mass % or more, 2 mass % or more, or 3 mass % or more, and may be 8 mass % or less, 7 mass % or less, or 6 mass % or less.

[0038] The base agent may further contain, in addition to the isocyanate-terminated prepolymer, a plasticizer, a solvent, etc. as a viscosity adjuster for adjusting the viscosity when the base agent and a curing agent described later are mixed. From an industrial and economical viewpoint, the base agent may further contain a catalyst and / or a retarder for efficiently reacting the isocyanate group of the alicyclic polyisocyanate with the hydroxyl group of the polyol. The base agent may contain an additive from the viewpoint of improving the finish, durability, adhesion to other materials, etc. of the waterproof material obtained.

[0039] The viscosity of the base agent at 23°C is preferably 1000 mPa·s or more, more preferably 3000 mPa·s or more, even more preferably 4000 mPa·s or more, particularly preferably 5000 mPa·s or more, and is preferably 25000 mPa·s or less, more preferably 20000 mPa·s or less, and even more preferably 15000 mPa·s or less, from the viewpoint of having a viscosity that allows the mixture immediately after mixing of the base agent and the curing agent to maintain leveling during application and ensure the thickness of the coating film. The viscosity of the base agent 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".

[0040] <Hardening agent> The curing agent may contain a crosslinking agent such as a hydroxyl compound such as polyhydric alcohol, or 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 glycol aminobenzoate, 1,3,5-triisopropyl-2,4-diaminobenzene, 1-methyl-3,5-diisopropyl-2,4-diaminobenzene, and the like. aminobenzene, 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'-disec-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 Aminodiphenylmethane, 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-4,4' aromatic polyamines such as N,N'-di-sec-butyl 4,4'-methylenebis(cyclohexylamine), isophorone diamine, norbornene diamine, N,N'-(dicyclohexylmethane 4,4'-diyl)-bisaspartic acid tetraethyl ester, alicyclic polyamines such as ethylene diamine, trimethylene diamine, triethylene tetramine, diethylene triamine, triaminopropane, 2,2,4-trimethylhexamethylene diamine, 2-hydroxyethyl ethylene diamine, N,The crosslinking agent may be an aliphatic polyamine such as N'-(2-methylpentane-1,5-diyl)-bisaspartic acid tetraethyl ester, polyoxyalkyleneamine, or polyetheramine. These crosslinking agents may be used alone or in combination of two or more. The curing agent preferably contains an aromatic polyamine, more preferably diethyltoluenediamine, as a crosslinking agent.

[0041] In addition to the crosslinking agent, the curing agent may further contain additives such as a plasticizer; a solvent; a catalyst; inorganic fillers such as calcium carbonate, talc, kaolin, zeolite, and diatomaceous earth; pigments such as chromium oxide, red iron oxide, iron oxide, carbon black, and titanium oxide; and wetting and dispersing agents, anti-settling agents, light stabilizers, defoamers, surface conditioners, and adhesion promoters.

[0042] <Waterproof material> In the set described above, the mixture is cured by mixing the base agent and the curing agent. The obtained cured product is suitable for use as a waterproofing material. That is, the waterproofing material according to one embodiment includes the cured product of the mixture of the base agent and the curing agent described above.

[0043] The waterproofing material according to the present embodiment is excellent in tensile strength, tear strength, and tensile product, and is a high-strength waterproofing material. When evaluated by a method conforming to JIS A 6021:2011 (coating waterproofing material for architecture, "high strength type"), for example, this waterproofing material is excellent in tensile strength, tear strength, and tensile product to such an extent that it satisfies the following values ​​stipulated in the said standard. Tensile strength (Tb): 10N / mm 2 End Tear strength (Tt): 30N / mm or more Tensile product (Tp): 700N / mm or more

[0044] The waterproofing material according to the present embodiment is also excellent in elongation at break, and is a highly elongated waterproofing material. When evaluated by a method conforming to JIS A 6021:2011 (architectural coating waterproofing material, "high elongation type (old type 1)"), this waterproofing material has excellent elongation at break to such an extent that it satisfies the following values ​​stipulated in the said standard. Elongation at break (Eb): 450% or more

[0045] An embodiment of a method for applying a waterproofing material using the above-mentioned set will be described. The application method according to the embodiment includes a step of obtaining a mixture of the base agent and the curing agent in the above-mentioned set (mixing step), and a step of applying the mixture to an object to be applied (application step).

[0046] In the mixing step, the temperature (environmental temperature) when the base agent and the curing agent are mixed may be, for example, -5 to 40°C.

[0047] When the curing agent contains a crosslinking agent, the curing agent may be mixed with the base agent so that the equivalent ratio of the active hydrogen groups of the crosslinking agent to the NCO group content in the base agent is 0.8 or more, 0.9 or more, or 1.0 or more. The curing agent may be mixed with the base agent so that the equivalent ratio of the active hydrogen groups of the crosslinking agent to the NCO group content in the base agent is 1.5 or less, 1.3 or less, or 1.2 or less.

[0048] When the curing agent contains polyamine, it is preferable to mix the main agent and the curing agent in the mixing step so that the equivalent ratio (NCO group / NH2 group) between the NCO group of the isocyanate-terminated prepolymer contained in the main agent and the amino group (NH2 group) contained in the curing agent is within a predetermined range from the viewpoint of obtaining a desired pot life. NCO group / NH2 group is preferably 0.8 or more, more preferably 0.9 or more, even more preferably 1.0 or more, and preferably 1.5 or less, more preferably 1.3 or less, even more preferably 1.2 or less.

[0049] In the coating step, the mixture is applied to a substrate before the mixture is cured. The substrate is not particularly limited and may be a wall surface, a floor surface, or the like of a building such as a house or a building. The mixture of the base agent and the curing agent according to this embodiment is particularly suitable for hand coating (hand coating) because it has a sufficient pot life. That is, hand coating may be performed in the mixing step. Hand coating includes mechanical coating such as automatic mixing devices such as static mixers and dynamic mixers, and coating using tools such as rollers, lysine guns, airless guns, and brushes. The mixture according to this embodiment may be applied by spraying (spray coating).

[0050] By using the set of base agent and hardener according to this embodiment, a sufficiently long pot life can be obtained when constructing the waterproofing material. More specifically, with the set of base agent and hardener according to this embodiment, for example, it takes 45 minutes or more for the viscosity of the mixture of base agent and hardener to reach 60,000 mPa·s at 23°C, or 55 minutes or more for the viscosity to reach 100,000 mPa·s, so that a sufficiently long pot life can be obtained for construction.

[0051] 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 and the like, which require high strength and high load performance, as a covering material for buildings, and as a rust inhibitor, etc. Depending on the application, it is also possible to add an organic solvent such as xylene to the mixture before construction depending on the workability. EXAMPLES

[0052] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0053] In the table below, the abbreviations in the table represent the following components. <Polypropylene glycol> PPG-1000: Polypropylene glycol (number average molecular weight 1000, product name "Actocol D-1000", manufactured by Mitsui Chemicals SKC Polyurethanes, Inc.) PPG-1500: Polypropylene glycol (number average molecular weight 1500, product name "Actocol D-1500", manufactured by Mitsui Chemicals SKC Polyurethanes, Inc.) PPG-2000: Polypropylene glycol (number average molecular weight 2000, product name "Actocol D-2000", manufactured by Mitsui Chemicals SKC Polyurethanes Co., Ltd.) PPG-3000: Polypropylene glycol (number average molecular weight 3000, product name "Actocol D-3000", manufactured by Mitsui Chemicals SKC Polyurethanes, Inc.)

[0054] <Polyether glycol> PTG-1000: Polytetramethylene ether glycol (number average molecular weight 1000, product name "PTG-1000SN", manufactured by Hodogaya Chemical Co., Ltd.) PTG-1400: Polytetramethylene ether glycol (number average molecular weight 1400, product name "PTG-1400SN", manufactured by Hodogaya Chemical Co., Ltd.) PTG-L1000: THF / methyl-substituted THF random copolymer (a random copolymer having a structural unit represented by the above formula (1) and a structural unit represented by the above formula (2), number average molecular weight 1000, trade name "PTG-L1000", manufactured by Hodogaya Chemical Co., Ltd.) PTG-2000: Polytetramethylene ether glycol (number average molecular weight 2000, product name "PTG-2000SN", manufactured by Hodogaya Chemical Co., Ltd.) PTG-2900: Polytetramethylene ether glycol (number average molecular weight 2900, product name "PTG-2900SN", manufactured by Hodogaya Chemical Co., Ltd.)

[0055] <Polyisocyanate> IPDI: Isophorone diisocyanate (product name "VESTANAT IPDI", manufactured by EVONIC) TDI (T-100): 2,4-tolylene diisocyanate (product name: Coronate T-100, manufactured by Tosoh Corporation) TDI (T-80): A mixture of 2,4-tolylene diisocyanate (80% by mass) and 4,4-tolylene diisocyanate (20% by mass) (product name "Coronate T-80", manufactured by Tosoh Corporation) XDI: Xylylene diisocyanate (product name "Takenate 500", manufactured by Mitsui Chemicals, Inc.)

[0056] <Preparation of base agent> In the examples and comparative examples, the base material was prepared by the following method based on the composition shown in Tables 1 and 2. A 2-liter glass flask was charged with polyether glycol and polypropylene glycol in a predetermined equivalent ratio, and dehydration was performed under reduced pressure at 95 to 105°C for 1 hour. After cooling until the liquid temperature was 40°C or less, a catalyst was added under a nitrogen gas flow and homogenized. Then, polyisocyanate was gradually added, and the mixture was heated at 60 to 80°C for 2 to 4 hours while stirring until the reaction was completed. The liquid after the reaction was cooled to room temperature, a viscosity modifier and the like were added, and the mixture was homogenized while stirring to obtain a base material (isocyanate-terminated prepolymer). All of the base materials in the examples and comparative examples were prepared so that the NCO group content was 4% by mass by adjusting the contents of the isocyanate-terminated prepolymer, the viscosity modifier, the additive, and the catalyst, in which the equivalent ratio between the NCO group of the polyisocyanate and the OH group of the polypropylene glycol and polyether glycol was adjusted.

[0057] <Pot life evaluation> The prepared base agent and the curing agent (including diethyltoluenediamine (trade name "Ethacure 100" manufactured by Albemarle Corporation)) were mixed so that the mass ratio of base agent to curing agent was 1:1 (NCO group / NH2 group = 1.1 (equivalent ratio)). The viscosity of the obtained mixture at 23°C was measured using a rotational viscometer (Toki Sangyo Co., Ltd. BH II type) in accordance with JIS K 7301:1995 "Test method 6.2 Viscosity for tolylene diisocyanate type prepolymer for thermosetting urethane elastomers". The pot life was determined as the time until the viscosity reached 60,000 mPa·s and 100,000 mPa·s, respectively. The measurement results are shown in Tables 1 and 2. If the time until the viscosity reached 60,000 mPa·s is 45 minutes or more and the time until the viscosity reached 100,000 mPa·s is 55 minutes or more, it can be said that the pot life is sufficient for application.

[0058] <Evaluation of physical properties (strength) of coating film (cured product)> For the Examples and Comparative Examples which were excellent in the evaluation of pot life, a coating film (cured product) was prepared from the above mixture in accordance with JIS A 6021:2011 (construction coating waterproofing material, high strength type), and after 7 days at 23°C, the tensile strength (Tb), tear strength (Tt), and tensile product (Tp) of the coating film were further evaluated. The results are shown in Tables 1 and 2. When Tb was 10 N / mm 2 Thus, if Tt is 30N / mm or more and Tp is 700N / mm or more, it can be said that the material has excellent properties as a waterproof material.

[0059] [Table 1]

[0060] [Table 2]

[0061] <Evaluation of physical properties of coating film (cured product) (elongation at break)> For Examples 1 to 9, the coating films (cured products) were evaluated for elongation at break (Eb) after 7 days at 23° C. in accordance with JIS A 6021:2011 (architectural coating waterproof material, high elongation type (old class 1)). The results are shown in Table 3.

[0062] [Table 3]

Claims

1. A method for improving pot life and post-cure tear strength in a set including a base material (excluding those containing water) containing an isocyanate group-terminated prepolymer and a curing agent, comprising the steps of: As the set, the isocyanate-terminated prepolymer is a reaction product of a polyol consisting of polypropylene glycol and a polyether glycol consisting only of a structural unit represented by the following formula (1), and an alicyclic polyisocyanate, The content of the polypropylene glycol is 25 equivalent % or more and 95 equivalent % or less based on the total amount of the polyol, The content of the polyether glycol is 5 equivalent % or more and 75 equivalent % or less based on the total amount of the polyol, The number average molecular weight of the polypropylene glycol is less than 2000; The method for improving the composition of the present invention uses a set of polyether glycols having a number average molecular weight of less than 2000. 【Chemistry 1】

2. 2. The method of claim 1, wherein the cycloaliphatic polyisocyanate is isophorone diisocyanate.

3. 3. The method of claim 1 or 2, wherein the curing agent is diethyltoluenediamine.

4. The method for improving viscosity according to any one of claims 1 to 3, wherein the base agent has a viscosity at 23°C of 1000 mPa·s or more and 25000 mPa·s or less.

Images