Two-component hand-applied urethane coating composition and method for constructing urethane waterproof coating layer

Abstract

To provide a two-component hand-applied urethane coating composition that exhibits high hardness and strength and offers sufficient pot life as well as excellent alkali-resistant water resistance and weather resistance.SOLUTION: A two-component hand-applied urethane coating composition in which a base agent contains an aliphatic and / or alicyclic isocyanate and a diol having a molecular weight of 500 or more, a diol having a molecular weight of less than 500, and a polyol having a functionality of 3 or more, 10 to 80 equivalent% of all polyols being formed of an aliphatic polyester polyol and / or an aliphatic polycarbonate polyol, with an NCO content of 3.0 to 6.0 mass%, a curing agent containing DETDA and an inorganic filler, a specific amount of a plasticizer being blended into the base agent or the curing agent, and further 5 to 40 mass% of a solvent relative to the composition being blended into the base agent and / or the curing agent, the solvent containing more than 30 mass% of a non-protonic solvent having a solubility parameter of 8.0 to 14.0, and a ratio of an amino group amount (milliequivalents) of an aromatic polyamine to a plasticizer amount (g) being 2.0 to 20.0.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a two-component hand-applied urethane coating composition (for coated flooring and waterproofing materials) and a method for applying a urethane waterproof coating layer using the composition. More specifically, the present invention relates to a two-component hand-applied urethane coating composition that is practically suitable for sports floors and heavy-traffic areas and has improved weather resistance to the point where a top coat is not required, and to a method for applying a urethane waterproof coating layer using the composition. [Background technology]

[0002] Because urethane floor coatings and waterproofing materials are suitable for construction in irregularly shaped and narrow spaces, they have been widely used for waterproofing verandas and eaves in apartment complexes and other housing complexes, waterproofing rooftops with many fixtures, and even full-scale rooftop waterproofing using breathable cushioning sheets. Meanwhile, areas subject to relatively heavy loads, such as sports floors and heavily pedestrianized corridors, require a high-hardness urethane coating waterproof layer with excellent elasticity and hardness as a finishing material. Furthermore, due to the serious labor shortage in recent years, there is a strong demand for labor-saving processes.

[0003] Currently used urethane waterproofing materials are classified into two types according to JIS A 6021 "Waterproof coating materials for construction": high elongation type and high strength type. The high elongation type is a general-purpose waterproofing material for hand application, and has an elongation rate at break (hereinafter referred to as "elongation rate") of 450% or more and a tensile strength of 2.3N / mm 2 The tensile strength of the above is specified as 280N / mm or more, and it is mainly used for non-walking or light walking parts. On the other hand, the high strength type has an elongation rate of 200% or more and a tensile strength of 10N / mm 2These products, which have a tensile strength of 700 N / mm or more, are often used for specialized applications such as waterproofing floors for parking lots, root-resistant waterproofing for rooftop greenery, and waterproofing for metal roofs. They are primarily made of ultra-fast-curing urethane materials that are sprayed using specialized spray equipment that impinges and mixes two highly reactive components. However, spray application poses a major problem: the scattering of mist generated during application. Care must be taken to protect the area around the application site with film and other protective materials, as well as to avoid damaging nearby homes and cars. Therefore, they are not suitable for application in densely populated residential areas or indoors. Furthermore, the spray equipment is expensive and requires dedicated technicians, limiting the number of construction companies that can perform this type of application.

[0004] Two-component hand-applied urethane waterproofing materials, which have few application problems, are mixed in a mixer and then hand-applied using a trowel, spatula, roller, or brush. In Japan, the outdoor temperatures differ greatly between winter and summer application, so it is common for summer formulations to be prepared for application at around 30°C and winter formulations for application at around 10°C. As an example, the time it takes for the viscosity to reach 60,000 to 100,000 mPa·s after mixing the two components (hereafter referred to as pot life) is targeted to be at least 45 minutes at 23°C for the summer formulation, and at least 30 minutes at 23°C for the winter formulation. It is also desirable that the urethane waterproofing material be applied in the evening and hardened enough to allow light walking by the next morning so that the next process can be carried out, and it is considered optimal that the time until the next process can be carried out (hereinafter referred to as the construction time) can be adjusted to within 17 hours throughout the year.

[0005] Generally, two-component hand-applied urethane waterproofing materials use plasticizers to ensure the pot life required for year-round application and to ensure high elongation and hardness. By replacing some of the plasticizer with a solvent that ultimately evaporates into the air, it is relatively easy to increase the resin concentration and hardness of the urethane coating. However, this accelerates the reaction between the base resin and the hardener, making it difficult to ensure sufficient pot life.

[0006] Furthermore, when the cured coating is exposed outdoors, it discolors in sunlight and has poor long-term weather resistance, so it is generally considered essential to apply a top coat such as an acrylic urethane paint over the coating to protect it. This top coat needs to be reapplied every four to five years. Furthermore, acrylic urethane paint contains a large amount of solvent, which raises concerns about its adverse impact on the environment.

[0007] Among two-component hand-applied urethane waterproofing materials, a two-component hand-applied urethane coating composition is known as a coating with relatively high hardness, which corresponds to the urethane rubber-based high-strength type of JIS A 6021, in which the main polyisocyanate contains isophorone diisocyanate (hereinafter referred to as IPDI) and the curing agent contains diethyltoluenediamine (hereinafter referred to as DETDA). Patent Document 1 reports a two-component hand-applied urethane waterproofing composition that corresponds to the high-strength urethane rubber type of JIS A 6021 and is composed of a base resin containing an isocyanate-terminated prepolymer made from IPDI and polyoxyalkylene polyol, and a curing agent containing an aromatic polyamine containing DETDA, a plasticizer, and an inorganic filler.However, because polyoxyalkylene polyol is used as the main component of the base polyol, the cured coating film when combined with the curing agent is prone to chalking when exposed to the outdoors and has poor weather resistance.

[0008] Patent Document 2 reports a method for producing polyurethane coated flooring and waterproofing materials with improved weather resistance to the point that a top coat is not required, consisting of a base resin containing an isocyanate-terminated prepolymer made from IPDI and polyester polyol, and a curing agent containing an aromatic polyamine containing DETDA and a plasticizer. However, because polyester polyol is used as the base polyol, the viscosity of the base resin increases, making it difficult to remove and mix the base resin from the can, especially during winter construction. Furthermore, the pot life tends to be shorter when combined with a curing agent, making it difficult to ensure sufficient pot life throughout the year. Furthermore, the above technology uses a liquid aliphatic polyester polyol with little crystallinity, but aliphatic polyester polyols in particular have problems with hydrolysis resistance, alkaline water resistance, and bacterial resistance, making them unsuitable for use around alkaline concrete structures, rooftop greening, and civil engineering fields, and they are hardly suitable for use in high-strength urethane waterproofing materials such as sports floors and heavy-foot traffic areas. While the use of aromatic polyester polyols would likely alleviate the above weaknesses to some extent, they would be even more viscous than aliphatic polyester polyols, further increasing application problems, and there are concerns about reduced weather resistance due to the aromatic skeleton. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-43740 [Patent Document 2] Japanese Patent Application Publication No. 10-17819 Summary of the Invention [Problem to be solved by the invention]

[0010] Spray-type ultra-fast-curing urethane waterproofing materials have issues such as the scattering of mist during application and the need for dedicated technicians. Meanwhile, the formulation technology for conventional two-component hand-applied urethane waterproofing materials has limitations in terms of ensuring sufficient pot life for summer application while still providing hardness and other properties that are practical for sports floors and heavy foot traffic. There has been a need for a two-component hand-applied urethane coating composition that maintains sufficient pot life throughout the year, has excellent alkaline water resistance, and is durable enough for sports floors and heavy foot traffic. Furthermore, there has been a need to provide a two-component hand-applied urethane coating composition that has improved weather resistance to the extent that it does not require the application of a top coat, thereby enabling labor-saving in the process. [Means for solving the problem]

[0011] In view of these problems, the present inventors have conducted extensive research into a two-component hand-applied urethane coating composition that has sufficient hardness and other properties to be practical for use on sports floors and those used for heavy foot traffic, has a sufficient pot life throughout the year, is highly resistant to alkaline water, and has weather resistance improved to the point where the application of a top coat is not necessary. As a result, the inventors have found a two-component hand-applied urethane coating composition that is composed of a base component containing an isocyanate-terminated prepolymer composed of polyisocyanate and polyol, and a curing agent containing an aromatic polyamine and an inorganic filler, in which the base polyisocyanate contains an aliphatic and / or alicyclic isocyanate, and the polyol contains an aliphatic polyester polyol and / or aliphatic polycarbonate polyol, The inventors have discovered that by adjusting the equivalent ratio of the diol with a molecular weight of 500 or more to the diol with a molecular weight of less than 500 and the polyol with a functionality of 3 or more within a specific range, using diethyltoluenediamine as the aromatic polyamine in the curing agent, adjusting the ratio of the amount of amino groups (milliequivalents) of the aromatic polyamine to the total amount of plasticizer (g) within a specific range, and using an aprotic solvent with a solubility parameter (SP value) within a specific range as the solvent, it is possible to obtain a two-component hand-applied urethane coating composition that has sufficient hardness and other properties for practical use on sports floors and for heavy foot traffic, has a sufficient pot life throughout the year, excellent alkaline water resistance, and has weather resistance improved to the point where the application of a top coat is not necessary, thereby completing the present invention.

[0012] The first invention is a two-component hand-applied urethane coating composition comprising a base agent containing an isocyanate-terminated prepolymer made of polyisocyanate and polyol, and a curing agent containing an aromatic polyamine and an inorganic filler, The polyisocyanate constituting the isocyanate group-terminated prepolymer in the base resin contains more than 70 equivalent percent of aliphatic and / or alicyclic isocyanate, and the NCO content of the base resin is 3.0 mass % to 6.0 mass %, the polyol constituting the isocyanate group-terminated prepolymer in the base resin contains 5 equivalent % to 95 equivalent % of diols having a molecular weight of 500 or more and 5 equivalent % to 95 equivalent % of diols having a molecular weight of less than 500 and polyols having a functionality of 3 or more, and 10 equivalent % to 80 equivalent % of the total polyols are aliphatic polyester polyols and / or aliphatic polycarbonate polyols; The curing agent contains more than 80 equivalent percent of all reactive components as aromatic polyamine, and more than 70 equivalent percent of the aromatic polyamine is diethyltoluenediamine, and the curing agent contains 20 mass % to 80 mass % of an inorganic filler; 5 to 40 parts by mass of plasticizer is mixed with 100 parts by mass of isocyanate-terminated prepolymer in the base compound as a curing agent, or as both the base compound and the curing agent, A solvent is blended into the base agent and / or curing agent in an amount of 5% by mass to 40% by mass based on the urethane coating composition, and the solvent contains more than 30% by mass of an aprotic solvent having a solubility parameter (SP value) of 8.0 to 14.0; The ratio of the amount of amino groups (milli-equivalents) of the aromatic polyamine to the mass (g) of the plasticizer is characterized by being 2.0 to 20.0. The second invention is a method for applying a urethane waterproof coating layer, which comprises applying a primer layer, or a primer layer and a urethane waterproofing material layer, to a substrate surface, and then applying the two-component hand-applied urethane coating composition of the first invention.

[0013] The present invention includes the following aspects. [1] A two-component hand-applied urethane coating composition comprising a base agent containing an isocyanate-terminated prepolymer composed of a polyisocyanate and a polyol, and a curing agent containing an aromatic polyamine and an inorganic filler, The polyisocyanate constituting the isocyanate group-terminated prepolymer in the base resin contains more than 70 equivalent percent of aliphatic and / or alicyclic isocyanate, and the NCO content of the base resin is 3.0 mass % to 6.0 mass %, the polyol constituting the isocyanate group-terminated prepolymer in the base resin contains 5 equivalent % to 95 equivalent % of diols having a molecular weight of 500 or more and 5 equivalent % to 95 equivalent % of diols having a molecular weight of less than 500 and polyols having a functionality of 3 or more, and 10 equivalent % to 80 equivalent % of the total polyols are aliphatic polyester polyols and / or aliphatic polycarbonate polyols; The curing agent contains more than 80 equivalent percent of all reactive components as aromatic polyamine, and more than 70 equivalent percent of the aromatic polyamine is diethyltoluenediamine, and the curing agent contains 20 mass % to 80 mass % of an inorganic filler; 5 to 40 parts by mass of plasticizer is mixed with 100 parts by mass of isocyanate-terminated prepolymer in the base compound as a curing agent, or as both the base compound and the curing agent, A solvent is blended into the base agent and / or curing agent in an amount of 5% by mass to 40% by mass based on the urethane coating composition, and the solvent contains more than 30% by mass of an aprotic solvent having a solubility parameter (SP value) of 8.0 to 14.0; A two-component urethane coating composition for hand application, in which the ratio of the amount of amino groups (milli-equivalents) of the aromatic polyamine to the mass (g) of the plasticizer is 2.0 to 20.0. [2] The two-component urethane coating composition for hand application according to [1], wherein the equivalent ratio of the isocyanate groups of the base agent to the amino groups of the aromatic polyamine in the curing agent is 0.9 to 1.5. [3] The JIS D hardness of the cured coating film of the urethane coating composition is 25 or more and the tensile strength is 10 N / mm 2 The two-component urethane coating composition for hand application according to [1] or [2] above. [4] A method for applying a urethane waterproof coating layer, comprising applying a primer layer, or a primer layer and a urethane waterproofing material layer, to a substrate surface, and then applying the two-component hand-applied urethane coating composition described in [1]. [Effects of the Invention]

[0014] The two-component hand-applied urethane coating composition of the present invention has sufficient hardness and other properties for practical use on sports floors and for heavy foot traffic, has a sufficient pot life throughout the year, has excellent alkaline water resistance, and has improved weather resistance to the extent that it does not require the application of a top coat. The application method for the urethane waterproof coating layer of the present invention does not require reinforcing materials such as glass mesh, and does not require the application of a top coat, so steps are omitted and application efficiency and economy are excellent. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention relates to a two-component urethane coating composition for hand application. The term "two-component" refers to a base agent and a curing agent. "Hand application" refers to a composition that is applied by hand using a trowel, spatula, roller, or brush. For weather resistance superior to the need for a topcoat, it is desirable to observe no significant cracking or deformation over a 500-hour test period exceeding the 325-hour accelerated exposure elongation degradation test specified in JIS A 6021. Furthermore, because no topcoat is required, superior durability is required compared to conventional coatings. For excellent alkaline water resistance, it is desirable to maintain tensile strength of at least 70% after immersion in alkaline water at 80°C for four weeks (JIS A 6021 requires tensile strength retention of at least 60% after immersion for seven days at 23°C). A pot life of at least 45 minutes at 23°C is desirable as a guideline for a sufficient year-round usable life.

[0016] To ensure sufficient performance as a coating layer for sports floors and heavy-traffic areas, the cured coating film of the two-component hand-applied urethane coating composition of the present invention must have a tensile strength of 10 N / mm, which is the high-strength standard of JIS A 6021 "Waterproof Coating Materials for Construction." 2 The tensile strength is preferably 700N / mm or more. The hardness is preferably 25 or more in JIS D hardness (durometer hardness test type D) according to the hardness test method for vulcanized rubber and thermoplastic rubber specified in JIS K 6253. The tensile strength is 10N / mm 2If the JIS D hardness is less than 25, impact resistance and abrasion resistance will be insufficient. On the other hand, the high-strength type standard requires an elongation rate of 200% or more, but conventional knowledge has shown that it is important to increase the elongation rate of waterproofing materials for substrates that are prone to cracking, such as concrete, and when applying to inorganic substrates such as concrete, even for high-strength types, it is desirable to increase the elongation rate as much as possible to 300% or more, and preferably 450% or more, the same as for high-elongation types, in order to ensure the crack-following ability that is a characteristic of urethane waterproofing materials.

[0017] The two-component hand-applied urethane coating composition of the present invention comprises a base agent containing an isocyanate-terminated prepolymer made from polyisocyanate and polyol, and a curing agent containing a plasticizer and an inorganic filler.

[0018] (Polyisocyanate) The polyisocyanate constituting the isocyanate-terminated prepolymer in the base resin must contain more than 70 equivalent percent aliphatic and / or alicyclic isocyanate, preferably 80 equivalent percent or more, and more preferably 90 equivalent percent or more. If the aliphatic and / or alicyclic isocyanate content is 70 equivalent percent or less, it becomes difficult to achieve weather resistance that is so good that a top coat is not required. As the aliphatic isocyanate and / or alicyclic isocyanate that can be used in the present invention, one or more aliphatic isocyanates and / or alicyclic isocyanates that can be used in polyurethane coating compositions can be freely selected and used, as long as the purpose and effects of the present invention are not impaired.

[0019] Aliphatic isocyanates include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate), hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4, Examples of the isocyanate include 4-trimethylhexamethylene diisocyanate, 2,6-diisocyanatomethylcaprate, lysine diisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,3,6-hexamethylene triisocyanate, trimethylhexamethylene diisocyanate, 1,5-pentamethylene diisocyanate (PDI), decamethylene diisocyanate, and derivatives thereof.

[0020] Alicyclic isocyanates include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), dimer acid diisocyanate, transcyclohexane-1,4-diisocyanate, and hydrogenated tolylene. Examples of suitable isocyanates include monocyclic alicyclic isocyanates such as diisocyanate (hydrogenated TDI), hydrogenated xylylene diisocyanate (hydrogenated XDI), and hydrogenated tetramethyl xylylene diisocyanate (hydrogenated TMXDI); and bridged cyclic alicyclic isocyanates such as norbornene diisocyanate, norbornane diisocyanate methyl, bicycloheptane triisocyanate, diisocyanatomethyl bicycloheptane, and di(diisocyanatomethyl)tricyclodecane, as well as derivatives thereof. Among these, it is preferable to use alicyclic isocyanates such as IPDI and hydrogenated XDI.

[0021] Furthermore, polyisocyanates other than aliphatic isocyanates and / or alicyclic isocyanates can also be used in combination as long as the amount is 30 equivalent percent or less. Aromatic polyisocyanates such as tolylene diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate can also be used in combination, but tolylene diisocyanate is a specified chemical substance under the Industrial Safety and Health Act and is therefore undesirable from an environmental perspective.

[0022] (Main NCO content and NCO / OH equivalent ratio) In the present invention, the NCO content of the base agent must be 3.0% to 6.0% by mass, and preferably 3.3% to 5.5% by mass. If the NCO content is 3.0% by mass or less, it is not possible to achieve a high hardness sufficient to withstand sports floors or heavy foot traffic. On the other hand, if the NCO content exceeds 6.0% by mass, the amount of DETDA, the main reactive component, increases, shortening the usable time and causing problems with application. The NCO / OH equivalent ratio, which is the equivalent ratio of the NCO groups of the polyisocyanate to the OH groups of the polyol during the production of the base resin, is preferably 1.5 to 2.5, and more preferably 1.6 to 2.3. If it is less than 1.5, the base resin will thicken significantly, and if it exceeds 2.5, the amount of free polyisocyanate will increase, which will likely cause problems such as a decrease in elongation and a shortened pot life.

[0023] (Main polyol) In the present invention, the polyol used in the base resin can be one or more of the polyols used in conventional polyurethane coating compositions, such as polyester polyols, polycarbonate polyols, polyether polyols, and polyalkylene polyols, but to ensure elongation, it is necessary to use 5 to 95 equivalent percent of a diol with a molecular weight of 500 or more, preferably 20 to 80 equivalent percent. If more than 95 equivalent percent of a diol with a molecular weight of 500 or more is used, the number of branching points in the cured product when combined with a curing agent will decrease and the concentration of urethane bonds will also decrease, resulting in a decrease in hardness development and curability, and even a decrease in final hardness. The polyol used in the base resin must further contain 5 to 95 equivalents of a diol with a molecular weight of less than 500 and a polyol with a functionality of 3 or more, preferably 20 to 80 equivalents. Using a diol with a molecular weight of less than 500 increases the concentration of urethane and urea bonds in the cured product, thereby achieving high hardness without significantly impairing elongation. Furthermore, using a polyol with a functionality of 3 or more creates branching points in the cured product, improving hardness development and curability, facilitating high hardness and improving alkaline aqueous resistance. If the combined amount of a diol with a molecular weight of less than 500 and a polyol with a functionality of 3 or more is less than 5 equivalents, high hardness and alkaline aqueous resistance will be insufficient. If the combined amount exceeds 95 equivalents, the base resin will become highly viscous and it will be difficult to ensure sufficient pot life and elongation.

[0024] Furthermore, 10 to 80 equivalent percent of the total polyols used in the base resin must be aliphatic polyester polyols and / or aliphatic polycarbonate polyols, preferably 20 to 75 equivalent percent, and more preferably 25 to 50 equivalent percent. Above 80 equivalent percent, alkaline water resistance is reduced. Furthermore, the viscosity of the base resin increases, making it difficult to remove and mix the base resin from the can, especially during winter application, and the usable life when combined with a curing agent cannot be ensured. On the other hand, below 10 equivalent percent, weather resistance sufficient to eliminate the need for a top coat cannot be achieved.

[0025] As the diol having a molecular weight of 500 or more, one or more of the diols having a molecular weight of 500 or more that have been conventionally used in polyurethane coating compositions, such as polyester diols, polycarbonate diols, polyether diols, etc., can be used. As the polyester diol having a molecular weight of 500 or more, it is preferable to use an aliphatic polyester diol and / or an aliphatic polycarbonate diol from the viewpoint of weather resistance. Examples of the aliphatic polyester diol having a molecular weight of 500 or more include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, and dodecanedioic acid, alicyclic dicarboxylic acids such as hexahydrophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid, and ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,3-butadiene glycol, and the like. Examples of suitable polyester polyols include polyester polyols obtained by dehydration condensation with hexanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol (3MPD), 2,4-diethyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, or a mixture thereof, and polylactone diols and polycaprolactone diols obtained by ring-opening polymerization of lactone monomers such as ε-caprolactone and methylvalerolactone. Among these, aliphatic polyester diols obtained from adipic acid or sebacic acid and 3-methyl-1,5-pentanediol (3MPD) are preferred. Examples of aliphatic polycarbonate diols having a molecular weight of 500 or more include those obtained by reacting at least one polyhydric alcohol such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, or diethylene glycol with diethylene carbonate, dimethyl carbonate, diethyl carbonate, or the like. As the polyether diol having a molecular weight of 500 or more, a general polyoxyalkylene diol having a molecular weight of 500 to 10,000 can be used, but it is preferable to use polyoxypropylene diol and polyoxyethylene propylene diol, which have low crystallinity and low viscosity. Furthermore, a bisphenol skeleton-containing polyether polyol having a molecular weight of 500 or more obtained by reacting a bisphenol compound with an alkylene oxide can also be used.

[0026] As the diol having a molecular weight of less than 500, one or more of the diols having a molecular weight of less than 500 that have been conventionally used in polyurethane coating compositions, such as polyester diols, polycarbonate diols, polyether diols, and polyalkylene diols, can be used. However, polyoxyalkylene diols having a molecular weight of 100 to less than 500, bisphenol skeleton-containing polyether polyols having a molecular weight of less than 500 obtained by reacting a bisphenol compound with an alkylene oxide, and alkane diols having a molecular weight of less than 500 are preferably used. Specifically, polyoxyalkylene diols such as polypropylene glycol 200 and polypropylene glycol 400, PO adducts of bisphenol A, and short-chain polyols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, and dipropylene glycol can also be used. Of these, polypropylene glycol 400 and 1,4-butanediol are preferred.

[0027] As the polyol having three or more functional groups, one or more of the polyols having three or more functional groups conventionally used in polyurethane coating compositions, such as polyester polyols, polycarbonate polyols, polyether polyols, and polyalkylene polyols, can be used. However, common polyoxypropylene triols or polyoxyethylene propylene triols with molecular weights of 200 to 10,000 are preferred. Polyoxypropylene polyols or polyoxyethylene propylene polyols with four or more functional groups tend to restrict elongation, so they can be used in small amounts. Furthermore, trifunctional short-chain polyols such as trimethylolpropane and glycerin, and tetrafunctional or higher short-chain polyols such as pentaerythritol and sorbitol also tend to restrict elongation, so they can only be used in small amounts.

[0028] (Main ingredient synthesis method) This method for synthesizing isocyanate-terminated prepolymers is preferably performed using a catalyst, since simply heating the polyisocyanate and polyol does not promote the reaction. While common urethane catalysts can be used, organotinic catalysts such as dibutyltin dilaurate (DBTDL) and dioctyltin dilaurate (DOTDL) are preferred, as they can efficiently promote the reaction with the addition of small amounts of 0.0001 to 0.1% by mass. The reaction temperature is preferably 60 to 100°C, and the reaction can be completed within 1 to 6 hours. After the reaction is complete, it is preferable to deactivate the catalyst with phosphoric acid or the like.

[0029] (active hydrogen in the curing agent) As a curing agent, in order to achieve high hardness, more than 80 equivalent % of all reaction components must be aromatic polyamine, and preferably more than 90 equivalent %. Polyol as a reaction component has some effect in ensuring elongation, but is less cohesive than aromatic polyamine, and is therefore not very effective in improving durability. Furthermore, diethyltoluenediamine (DETDA) must account for more than 70 equivalent percent of the aromatic polyamine, preferably more than 80 equivalent percent, and more preferably more than 90 equivalent percent. If the amount of amorphous, highly reactive DETDA is less than 70 equivalent percent, it becomes difficult to achieve curing due to good reactivity with aliphatic and / or alicyclic isocyanates.

[0030] Examples of aromatic polyamines that can be used in combination with the curing agent include Curehard (registered trademark) MED (4,4'-methylenebis(2-ethyl-6-methylaniline)) manufactured by Kumiai Chemical Industry Co., Ltd., which has a high reactivity similar to DETDA, Kayahard (registered trademark) AA (4,4'-methylenebis(2-ethylaniline)) manufactured by Nippon Kayaku Co., Ltd., Kayabond (registered trademark) C-300 (4,4'-methylenebis(2,6-diethylaniline)) manufactured by Nippon Kayaku Co., Ltd., and Kayabond (registered trademark) C-400 (4,4'-methylenebis(2,6-diisopropylaniline)) manufactured by Nippon Kayaku Co., Ltd. Furthermore, although they are aromatic polyamines with low reactivity, Ethacure 420 (4,4'-methylenebis(N-sec-butylaniline)) manufactured by Albemarle Corporation and Ethacure 300 (dimethylthiotoluenediamine) manufactured by Albemarle Corporation can also be used.

[0031] Polyols may be used as reaction components as long as their content is 20 equivalent percent or less. Polyols with a molecular weight of less than 1,500 are preferred. Examples include short-chain polyols such as 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, ethylene glycol, diethylene glycol, dipropylene glycol, and tripropylene glycol, as well as relatively cohesive polyols such as polyester polyols and polycarbonate polyols. Among these, primary hydroxyl group polyols are more preferred because they are highly reactive and less likely to remain unreacted. Among these, 1,3-propanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, and aromatic polyester polyols with a molecular weight of 300 to 800 are even more preferred for achieving high hardness. Incidentally, the aromatic polyester polyol is preferably a liquid product using a low-crystalline polyol such as Kurapol (manufactured by Kuraray Co., Ltd.). Polyols having a molecular weight of 1500 or more can also be used, including polyoxypropylene polyols and polyoxyethylene propylene polyols, which have low viscosity, but are not preferred from the viewpoint of achieving high hardness due to their low cohesion.

[0032] (solvent) In the present invention, the solvent must contain more than 30% by mass of an aprotic solvent with a solubility parameter (SP value) of 8.0 to 14.0, and the total solvent must be blended into the base resin and / or curing agent so that it accounts for 5% to 40% by mass of the urethane coating composition. Here, aprotic means that the solvent does not contain active hydrogen (such as a hydroxyl group, amino group, or carboxylic acid group) that reacts with the isocyanate group of the isocyanate-terminated prepolymer contained in the base resin. The solubility parameter (SP value) in the present invention refers to the Hansen solubility parameter, which is an index that serves as a measure of the solubility of a binary solution. SP value δ((cal / cm 3 ) 1 / 2The following formula (1) was used to calculate δ=((δd 2 +δp 2 +δh 2 ) / 4.2) 1 / 2 ···(1) Here, δd is the London dispersion force term, δp is the molecular polarization term, and δh is the hydrogen bond term. Also, the values ​​(δd, δp, δh: units (J / cm)) listed in the Hansen Solubility Parameters software (HSPiP ver. 4.1.x) or "HANSEN SOLBILITY PARAMETERS" A User's Handbook Second Edition are used. 3 ) 1 / 2 ) can be calculated based on When multiple solvents were used, the SP value was calculated as a weighted average of the SP values ​​of the individual solvents using the following formula (2). m=δ1φ1+δ2φ2 (2) Here, δ1 and δ2 are the SP values ​​of each solvent component, and φ1 and φ2 are the volume fractions of each solvent component.

[0033] In the present invention, the total amount of solvents must be 5 to 40% by mass, preferably 15 to 30% by mass, based on the urethane coating composition, and is blended into the base agent and / or curing agent. If the total solvent content is less than 5% by mass of the urethane coating composition, it is difficult to ensure a sufficient working life. On the other hand, if the total solvent content exceeds 40% by mass of the urethane waterproofing composition, there is a risk of shrinkage due to evaporation after application and it tends to make the inorganic filler more susceptible to settling, which is undesirable. In the present invention, more than 30% by mass of the total solvent must be an aprotic solvent with a solubility parameter (SP value) of 8.0 to 14.0, preferably 35% by mass or more, and more preferably 40% by mass or more. It is acceptable for all solvents to be aprotic solvents with a solubility parameter (SP value) of 8.0 to 14.0. If the aprotic solvent accounts for 30% by mass or less of the total solvent amount, it is difficult to ensure a sufficient usable life. If the solubility parameter (SP value) of the aprotic solvent is less than 8.0, it is difficult to ensure a sufficient usable life, and if it exceeds 14.0, the hardness of the coating film will be insufficient, which is undesirable. On the other hand, an aprotic solvent with a solubility parameter (SP value) of less than 8.0 or more than 14.0 may be used in combination, provided that it accounts for less than 70% by mass of the total solvent. Examples of non-polar solvents that can be used in combination and have a solubility parameter (SP value) of less than 8.0 or more than 14.0 include aromatic-containing petroleum hydrocarbon solvents, aliphatic and alicyclic petroleum hydrocarbon solvents, and alicyclic hydrocarbon solvents having 7 to 10 carbon atoms. Specifically, MC-2000 Solvent (SP value = 7.2 to 7.8, a mixture of normal paraffin and isoparaffin having 9 to 11 carbon atoms, manufactured by Sankyo Chemical Co., Ltd.) is preferably used. In the present invention, it is preferable not to use a protic solvent that may react with the isocyanate group of the isocyanate-terminated prepolymer contained in the base resin.

[0034] In the present invention, aprotic solvents such as ethers, esters, ketones, nitriles, and aromatic hydrocarbons having a solubility parameter (SP value) of 8.0 to 14.0 can be used. Examples of ethers or esters include dialkyl glycol ethers such as ethylene glycol dimethyl ether (SP value = 8.6), diethylene glycol dimethyl ether (SP value = 8.8), diethylene glycol diethyl ether (SP value = 8.7), and diethylene glycol dibutyl ether (SP value = 8.3), cyclic ethers such as 1,4-dioxane (SP value = 10.0), aromatic ethers such as anisole (SP value = 9.4), ethylene glycol monomethyl ether acetate (SP value = 10.0), ethylene glycol monoethyl ether acetate (SP value = 9.6), ethylene glycol monobutyl ether acetate (SP value = 8.9), and diethylene glycol monoethyl ether acetate (SP value = 8.9). Examples of suitable esters include glycol ether acetates such as propylene glycol monomethyl ether acetate (SP value = 9.4), diethylene glycol monobutyl ether acetate (SP value = 9.0), propylene glycol monomethyl ether acetate (SP value = 8.7), propylene glycol monoethyl ether acetate (SP value = 9.0), dipropylene glycol monomethyl ether acetate (SP value = 9.2), and methoxybutyl acetate (SP value = 8.7); carbonates such as dimethyl carbonate (SP value = 9.9) and diethyl carbonate (SP value = 8.8); fatty acid esters such as ethyl acetate (SP value = 9.1) and gamma-butyrolactone (SP value = 12.6); and benzoate esters such as methyl benzoate (SP value = 10.5). Other examples include ketones such as acetylacetone (SP value = 10.6) and acetophenone (SP value = 10.6), nitriles such as acetonitrile (SP value = 11.9) and benzonitrile (SP value = 8.4), amides such as N,N-dimethylformamide (SP value = 12.1) and N,N-dimethylformacetamide (SP value = 10.8), and aromatic hydrocarbons such as toluene (SP value = 8.9) and 1,2-dichlorobenzene (SP value = 10.0). Among them, diethylene glycol dimethyl ether (SP value = 8.8), 1,4-dioxane (SP value = 10.0), anisole (SP value = 9.4), propylene glycol monomethyl ether acetate (SP value = 8.7), methoxybutyl acetate (SP value = 8.7), dimethyl carbonate (SP value = 9.9), diethyl carbonate (SP value = 8.8), ethyl acetate (SP value = 9.1), γ-butyrolactone (SP value = 12.6), methyl benzoate (SP value = 10.5), acetylacetone (SP value = 10.6), acetophenone (SP value = 10.6), acetonitrile (SP value = 11.9), benzonitrile (SP value = 8.4), N,N-dimethylformamide (SP value = 12.1), N,N-dimethylformacetamide (SP value = 10.8), toluene (SP value = 8.9), 1,2-dichlorobenzene (SP value = 10.0) are preferred, and propylene glycol monomethyl ether acetate (SP value = 8.7) and methoxybutyl acetate (SP value = 8.7) are most preferred.

[0035] The boiling point of the solvent used in the present invention is preferably in the range of 70 to 250°C, and more preferably 100 to 200°C. If the boiling point exceeds 250°C, the solvent tends to remain in the waterproof coating film without volatilizing, which can cause a decrease in hardness, etc. On the other hand, if the boiling point is less than 70°C, the solvent tends to volatilize from the curing agent, which can cause problems with the stability of the curing agent and the working environment, and is therefore undesirable.

[0036] (inorganic filler) The curing agent must contain 20% to 80% by mass of inorganic filler. Without the reinforcing effect of the inorganic filler, high hardness will be inefficient and the waterproof coating layer will not be practical. If the inorganic filler content is less than 20% by mass, the reinforcing effect will be insufficient, and if it exceeds 80% by mass, thickening will occur, resulting in poor workability. The amount of inorganic filler to be contained is preferably 30% to 75% by mass, and more preferably 40% to 70% by mass.

[0037] Calcium carbonate is preferred as an inorganic filler. Calcium carbonate is economically effective, has good dispersibility during hardener production, and even when used in large amounts, it does not thicken the hardener. It also reduces sedimentation during storage, and has few adverse effects on physical properties. Various types of calcium carbonate are available, including heavy calcium carbonate, light calcium carbonate, and surface-treated colloidal calcium carbonate. Any of these can be used as a waterproofing material for vertical surfaces, imparting thixotropy with surface-treated colloidal calcium carbonate. Inorganic fillers such as silica, kaolin, talc, bentonite, aluminum hydroxide, and barium hydroxide can also be used. Since these inorganic fillers contain adhering water, the moisture content of the hardener is approximately 1000 ppm to 3000 ppm. It is believed that this adhering water gradually reacts with excess isocyanate groups after the two components are mixed, contributing to improved physical properties.

[0038] (plasticizer) Next, to ensure a year-round pot life and high elongation and hardness, 5 to 40 parts by weight of plasticizer is required per 100 parts by weight of isocyanate-terminated prepolymer in the base resin, with 10 to 35 parts by weight being preferred, and 20 to 30 parts by weight being most preferred. Less than 5 parts by weight of plasticizer makes it difficult to ensure pot life and elongation, while more than 40 parts by weight weakens the coating. While plasticizers are generally blended with the curing agent, it is also possible to blend some of them with the base resin. That is, the plasticizer is blended with the curing agent, or separately with both the base resin and the curing agent.

[0039] Plasticizers that can be used include those commonly used in urethane resins. Examples include phthalates such as diisononyl phthalate (DINP), dioctyl phthalate (DOP), and butyl benzyl phthalate (BBP), aliphatic dibasic acid esters, phosphate esters, trimellitates, sebacic acid esters, epoxy fatty acid esters, glycol esters, animal and vegetable oil-based fatty acid esters, petroleum and mineral oil-based plasticizers, and alkylene oxide polymerization-based plasticizers. Among these, diisononyl phthalate (DINP) and dioctyl phthalate (DOP), which have a flash point of 200°C or higher, are preferred because they are unlikely to lose weight over the long term and are aromatic polyesters that are unlikely to undergo hydrolysis.

[0040] (Amino group equivalent per plasticizer) When the base resin and curing agent are mixed, the ratio of the amount of amino groups (milliequivalents) in the aromatic polyamine to the amount of plasticizer (g) ("amino groups (milliequivalents) / plasticizer (g)" (hereinafter also referred to as "the ratio of the amount of amino groups (milliequivalents) in the aromatic polyamine to the mass (g) of plasticizer" or "amino group equivalents per plasticizer") must be in the range of 2.0 to 20.0, preferably 2.5 to 15.0, and most preferably 2.8 to 13.0. If the "amino group equivalents per plasticizer" is less than 2.0, the concentration of aromatic polyamine will be low and the coating will become brittle, while if it is more than 10.0, it will be difficult to ensure a sufficient usable time.

[0041] (Isocyanate group / aromatic amino group equivalent ratio) The equivalent ratio of the isocyanate groups in the base resin to the amino groups in the aromatic polyamine in the curing agent (hereinafter referred to as the "isocyanate group / aromatic amino group equivalent ratio") is preferably in the range of 0.9 to 1.5, more preferably 0.92 to 1.40, and even more preferably 0.95 to 1.35. If the isocyanate group / aromatic amino group equivalent ratio exceeds 1.5, curability decreases, and if it is less than 0.9, the number of terminal amino groups increases during the curing process, weakening the coating film.

[0042] (curing accelerator) In the present invention, organic stannic compounds, tertiary amines, metal carboxylates, and the like, which are believed to have a moisture-curing-accelerating effect in the reaction with isocyanate groups, can be used as reaction accelerators. Examples of organostannic compounds include dibutyltin oxide, dioctyltin oxide, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin di-2-ethylhexanoate, dioctyltin diacetate, dioctyltin dilaurate, dibutyltin dimercaptide, dibutyltin bisacetylacetonate, dibutyltin oxylaurate, dioctyltin dineodecanoate, dibutyltin bisbutylmaleate, and dioctyltin 2-ethylhexylmaleate, with dibutyltin dilaurate and dioctyltin dilaurate being preferred. The organostannic compound is preferably used in an amount of 0.001 to 0.1% by mass in the curing agent.

[0043] Tertiary amines include common tertiary amines such as triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, bis(2-morpholinoethyl)ether, and diazabicycloundecene. However, imidazole compounds, which are specialized tertiary amines, are preferred for their foam suppression and cure acceleration effects. Examples of imidazole compounds include compounds with substituents at the 1st and 2nd positions, such as 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-benzyl-2-methylimidazole, and 1-benzyl-2-phenylimidazole, as well as compounds with a substituent at the 1st position, such as 1-methylimidazole and 1-allylimidazole. Among these, imidazole compounds with substituents at the 1st and 2nd positions are preferred due to their enhanced cure acceleration effect. It is preferable to use 0.01 to 2.0% by mass of the tertiary amine in the curing agent.

[0044] Metal carboxylates, which are generally used as urethane catalysts, can also be used. While metal carboxylates have a weak moisture-cure-accelerating effect, they strongly promote the reaction with aromatic polyamines, shortening the working time and curing time, making them preferable for use as winter catalysts rather than summer catalysts. Examples of metal carboxylates include lead salts, zinc salts, bismuth salts, zirconium salts, tin salts, copper salts, magnesium salts, calcium salts, strontium salts, and barium salts of 2-ethylhexanoic acid, neodecanoic acid, naphthenic acid, oleic acid, linoleic acid, linolenic acid, and resin acid. Of these, calcium 2-ethylhexanoate and zinc 2-ethylhexanoate are preferred due to their high hardness-promoting effect. Metal carboxylates are preferably used in an amount of 0.1 to 4.0% by mass in the curing agent. Meanwhile, lead carboxylates are effective in shortening the working time and curing time, but their use is not recommended from an environmental perspective.

[0045] As described above, any compound that is thought to promote moisture curing can be used. Among these, organostannic compounds and imidazole compounds are particularly suitable as catalysts for use in summer, as they can promote curing without shortening the usable time and are also excellent at suppressing foaming. Furthermore, imidazole compounds are more preferable because, while metal catalysts tend to accelerate thermal degradation when added in large amounts, they hardly accelerate thermal degradation even when added in large amounts. While moisture-cure accelerators are generally blended with the curing agent, a corresponding amount can be added when mixing the two components at the construction site. While it is possible to blend them with the base resin, this is not recommended because it may impair storage stability.

[0046] On the other hand, carboxylic acids or acid anhydrides accelerate the reaction between isocyanate prepolymers and aromatic polyamines, which is effective in shortening pot life and curing time, and they hardly accelerate thermal degradation like carboxylic acid metal salts, so they are particularly suitable as winter accelerators. However, because they have almost no moisture-cure acceleration effect, they are not very effective in formulations with a high isocyanate group / aromatic amino group equivalent ratio. Examples of the carboxylic acid include propionic acid, 2-methylpentanoic acid, octylic acid, isononanoic acid, and naphthenic acid, with octylic acid being preferred. Examples of acid anhydrides include phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, succinic anhydride, and maleic anhydride, with methyltetrahydrophthalic anhydride being preferred. The carboxylic acid and acid anhydride are preferably used in an amount of 0.05 to 2.0% by mass in the curing agent, and a part or all of the amount may be blended into the base resin.

[0047] Furthermore, it is preferable to premix the acid anhydride catalyst with the base agent or to premix the acid anhydride when mixing the base agent and curing agent. However, the method of adding the acid anhydride at the construction site each time construction is carried out has problems such as storage stability and management of the acid anhydride, and measurement errors due to the complexity at the construction site, so it is more preferable to premix the acid anhydride with the base agent.

[0048] (Other additives) In addition, additives such as wetting agents, antifoaming agents, pigments, and weather resistance agents may be blended with the curing agent as needed.

[0049] (Base agent / hardener mixture ratio) The blending ratio of the base agent to the curing agent is not particularly limited, but is preferably in the range of 1 / 1 to 1 / 2 by mass. However, since a 1 / 2 blend generally reduces the resin content of the base agent, which is detrimental to durability, a ratio of 1 / 1 to 1 / 1.75 is preferred, and a ratio of 1 / 1 to 1 / 1.5 is even more preferred.

[0050] (Urethane coating composition) Since one of the purposes of this invention is to waterproof substrates that are prone to cracking over time, such as concrete substrates, emphasis is placed on ensuring the elongation required for crack tracking. Therefore, while the JIS standard for high-strength urethane waterproofing materials requires an elongation of 200% or more, it is preferable to make the elongation 300% or more, and more preferably 450% or more. As a result, the tensile strength is much higher than that of conventional waterproofing materials, and the coating layer is resistant to destruction even without reinforcing fabric, making it possible to use an installation method that does not require reinforcing mesh.For waterproofing large areas of roofs, the conventional ventilation buffer method of deaerating the water (moisture) in the base concrete is recommended, but for small areas and in areas that require a lot of work in the past, such as rises, eaves, areas around accessories, and gutters, waterproofing performance can be achieved without inserting reinforcing fabric (mesh), achieving significant labor savings.

[0051] (Urethane waterproof coating layer construction method) The second invention relates to a method for applying a urethane waterproof coating layer to sports floors and heavy-traffic floors. The second invention is a method for applying a urethane waterproof coating layer, which comprises applying a primer layer, or a primer layer and a urethane waterproofing material layer, to a substrate surface, and then applying the two-component hand-applied urethane coating composition of the first invention. The application method of the present invention cannot be applied directly to inorganic substrates such as concrete. Because urethane waterproofing materials do not adhere to inorganic substrates, they can be applied after applying a primer that can block moisture from the substrate to some extent and ensure adhesion. In some cases, including during renovations, an intermediary primer can be applied over an existing urethane waterproofing layer. Furthermore, the coating can be applied to inorganic substrates over breathable buffer sheets, polymeric sheets such as PVC sheets, rubber sheets, or nonwoven fabric sheets secured with primer, adhesive, mechanical fixing, or laying. Furthermore, since direct application of the urethane coating layer for sports floors or heavy-traffic surfaces using the application method of the present invention to metal substrates does not ensure adhesion, it must be applied after applying a specialized primer. The primer layer of the present invention can be the same as that typically used for urethane waterproofing layers.

[0052] In the application method of the present invention, a primer is applied to an inorganic substrate, followed by a conventional low-hardness, high-elongation two-component or one-component waterproofing material, and then the high-strength coating composition of the present invention is applied on top of that. By creating a two-layer structure with different hardnesses, the lower layer's low hardness serves to buffer the movement of cracks that may occur in the substrate, while the upper layer is a high-hardness layer with high elongation and strength, creating a waterproof layer that will not break even without the use of a reinforcing fabric. Furthermore, after applying the high-strength waterproofing material of the present invention, polymer-based waterproofing materials such as PVC, root barrier sheets, non-slip materials, and various molded products can be installed on top of the coating. [Example]

[0053] raw materials The raw materials used in the following examples and comparative examples are as follows. [Isocyanate] IPDI: Isophorone diisocyanate, VESTANAT® IPDI (trade name), NCO content 37.8% by mass, NCO functionality approximately 2.0, manufactured by Evonik Japan Co., Ltd. Hydrogenated XDI: hydrogenated xylene diisocyanate, Takenate (registered trademark) 600 (trade name), NCO content 43.3 mass%, NCO functionality approximately 2.0, manufactured by Mitsui Chemicals, Inc. [Polyol] PA-2000: Polyoxypropylene diol, Sannix (registered trademark) PA-2000 (trade name), average molecular weight 2000, OH value 56.1 mgKOH / g, manufactured by Sanyo Chemical Industries, Ltd. PP-400: Polyoxypropylene diol, Sannix (registered trademark) PP-400 (trade name), average molecular weight 400, OH value 280.5 mg KOH / g, manufactured by Sanyo Chemical Industries, Ltd. GA-3000: Polyoxypropylene triol, Sannix (registered trademark) GA-3000 (trade name), average molecular weight 3000, OH value: 56.1 mg KOH / g, manufactured by Sanyo Chemical Industries, Ltd. GP-600: Polyoxypropylene triol, Sannix (registered trademark) GP-600 (trade name), average molecular weight 600, OH value: 279 mg KOH / g, manufactured by Sanyo Chemical Industries, Ltd. V278: Aliphatic polyester diol, average molecular weight 1800, OH value: 63 mg KOH / g, manufactured by Air Water Performance Chemicals Inc. V429: Aliphatic polyester diol, average molecular weight 1500, OH value: 77 mg KOH / g, manufactured by Air Water Performance Chemicals Inc. V425: Aliphatic polyester diol, average molecular weight 1000, OH value: 112 mg KOH / g, manufactured by Air Water Performance Chemicals Inc. PDP-70: Aromatic polyester diol, STENPANPOL (registered trademark) PDP-70 (trade name), average molecular weight 1600, OH value: 70.1 mg KOH / g, manufactured by Stepan Company 220EB: Aliphatic polyester diol, PLACCEL (registered trademark) 220EB (trade name), OH value: 56.1 mg KOH / g, manufactured by Daicel Corporation PCDX-208: Aliphatic polycarbonate diol, DURANOL (registered trademark) PCDX-208 (trade name), average molecular weight 2000, OH value: 56.1 mg KOH / g, manufactured by Asahi Kasei Corporation T5650E: Aliphatic polycarbonate diol, DURANOL (registered trademark) T5650E (trade name), average molecular weight 500, OH value: 224.4 mg KOH / g, manufactured by Asahi Kasei Corporation T5650J: Aliphatic polycarbonate diol, DURANOL (registered trademark) T5650J (trade name), average molecular weight 800, OH value: 140.2 mg KOH / g, manufactured by Asahi Kasei Corporation P-2050: Aliphatic polyester diol, Kuraray Polyol P-2050 (trade name), average molecular weight 2000, OH value: 56.1 mg KOH / g, manufactured by Kuraray Co., Ltd. P-2010: Aliphatic polyester diol, Kuraray Polyol P-2010 (trade name), average molecular weight 2000, OH value: 56.1 mg KOH / g, manufactured by Kuraray Co., Ltd. P-510: Aliphatic polyester diol, Kuraray Polyol P-510 (trade name), average molecular weight 500, OH value: 224.4 mg KOH / g, manufactured by Kuraray Co., Ltd. F-1010: Aliphatic polyester triol, Kuraray Polyol F-1010 (trade name), average molecular weight 1000, OH value: 167.4 mg KOH / g, manufactured by Kuraray Co., Ltd. 1,4-BD: 1,4-butanediol (trade name), manufactured by Mitsubishi Chemical Corporation [Polyamine] DETDA: Diethyltoluenediamine, Ethacure 100 (trade name), manufactured by Albemarle Japan Co., Ltd. 〔catalyst〕 DOTDL: Dioctyl tin dilaurate, KS-1200A-1 (trade name), manufactured by Kyodo Pharmaceutical Co., Ltd. U-CAT (registered trademark) IM240: 1-isobutyl-2-methylimidazole, U-CAT (registered trademark) IM240 (product name), manufactured by San-Apro Co., Ltd. 〔solvent〕 MC-2000: MC-2000 Solvent (trade name), a mixture of normal paraffins and isoparaffins with carbon numbers of 9 to 11, SP value: 7.2 to 7.8, manufactured by Sankyo Chemical Co., Ltd. PMA: Propylene glycol monomethyl ether acetate, PMA (trade name), SP value: 8.7, manufactured by Sankyo Chemical Co., Ltd. Methacetate: Methoxybutyl acetate, SP value: 8.8, manufactured by Sankyo Chemical Co., Ltd. DMSO: Dimethyl sulfoxide, SP value: 14.5, manufactured by Nacalai Tesque, Inc. [Plasticizer] DINP: Diisononyl phthalate, Sanso Cizer (registered trademark) DINP (trade name), manufactured by New Japan Chemical Co., Ltd. [Inorganic filler] NS#100: Calcium carbonate, NS#100 (product name), manufactured by Nitto Funka Kogyo Co., Ltd. Additives: Kusumoto Chemical Co., Ltd. [Commercially available waterproofing auxiliary materials] Primer: Fast-curing OT Primer M Blue, OT Primer QQ (product name), manufactured by Tajima Roofing Co., Ltd. Reinforcement fabric: Mesh UB (product name), manufactured by Tajima Roofing Co., Ltd. [Commercially available general-purpose waterproofing materials] High-stretch JIS-compliant general-purpose waterproofing material: Ortack Ace (product name), manufactured by Tajima Roofing Co., Ltd.

[0054] Preparation of the main agent According to the formulations in Tables 1 to 4, a four-neck flask was charged with the specified polyol, solvent, and dioctyltin dilaurate, followed by the specified polyisocyanate compound. After that, the mixture was reacted at 90 to 100°C for 1 to 2 hours with stirring to obtain each base compound.

[0055] Preparation of curing agent According to the formulations in Tables 1 to 4, the specified liquids were charged into a metal container and mixed uniformly at low speed with a mixer (dissolver blade), after which a specified amount of calcium carbonate was added and mixed at 1500 rpm for 10 minutes to obtain each curing agent.

[0056] Example 1 In Example 1, the base agent and curing agent were prepared according to the formulation in Table 1. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Example 1, which used 20% by mass of PMA, which has a solubility parameter (SP value) of 8.7, as the solvent and 20% by equivalent of the aliphatic polyester polyol V278, had a pot life of 68 minutes, a tensile strength ratio of 88% after four weeks in alkaline water at 80°C, and good weather resistance, providing sufficient pot life throughout the year, excellent alkaline water resistance, and weather resistance that did not require the application of a top coat. Furthermore, the initial physical properties of the cured coating showed good coating properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0057] Example 2 In Example 2, the base agent and curing agent were prepared according to the formulation in Table 1. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Example 2, which used 20% by mass of PMA as the solvent and 40% by equivalent of the aliphatic polyester polyol V278, had a pot life of 57 minutes, a tensile strength ratio of 85% after 4 weeks in alkaline water at 80°C, and good weather resistance, providing a pot life sufficient for the entire year, excellent alkaline water resistance, and weather resistance that did not require the application of a top coat. Furthermore, the initial physical properties of the cured coating showed good coating properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0058] Example 3 In Example 3, the base agent and curing agent were prepared according to the formulation in Table 1. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Example 3, which used 20% by mass of PMA as the solvent and 60% by equivalent of the aliphatic polyester polyol V278, had a pot life of 53 minutes, a tensile strength ratio of 81% after four weeks of alkaline aqueous solution at 80°C, and good weather resistance, providing sufficient pot life throughout the year, excellent alkaline water resistance, and weather resistance that did not require the application of a top coat. Furthermore, the initial physical properties of the cured coating showed good coating properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0059] Example 4 In Example 4, the base agent and curing agent were prepared according to the formulation in Table 1. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Example 4, which used 20% by mass of PMA as the solvent and 75% by equivalent of the aliphatic polyester polyol V425, had a pot life of 70 minutes, a tensile strength ratio of 74% after four weeks of alkaline water treatment at 80°C, and good weather resistance, providing sufficient pot life throughout the year, excellent alkaline water resistance, and weather resistance that did not require the application of a top coat. Furthermore, the initial physical properties of the cured coating showed good coating properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0060] Comparative Example 1 In Comparative Example 1, the base agent and curing agent were prepared according to the formulation in Table 1. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Comparative Example 1, in which PMA was used as a solvent at 20% by mass relative to the base resin and no aliphatic polyester polyol was used at all, had a pot life of 76 minutes and a tensile strength ratio of 90% after 4 weeks of alkaline aqueous immersion at 80°C, but cracks occurred during the weather resistance test.

[0061] Comparative Example 2 In Comparative Example 2, the base agent and curing agent were prepared according to the formulation in Table 1. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Comparative Example 2, which used 20% by mass of PMA as the solvent relative to the base resin and 85% by equivalent of V429, an aliphatic polyester polyol, had a pot life of 55 minutes and good weather resistance, but the tensile strength ratio after 4 weeks in alkaline water at 80°C was 56%, indicating insufficient alkaline water resistance.

[0062] Comparative Example 3 In Comparative Example 3, the base agent and curing agent were prepared according to the formulation in Table 1. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Comparative Example 3, in which MC-2000, which has a solubility parameter (SP value) of 7.2 to 7.8, was used as the solvent in an amount of 20 mass % relative to the base resin, and aliphatic polyester polyol was used in an amount of 100 equivalent %, had good weather resistance, but the pot life was 19 minutes and the tensile strength ratio after 4 weeks in alkaline water at 80°C was 48%, which was not a sufficient pot life throughout the year, and the alkaline water resistance was also insufficient.

[0063] Example 5 Example 5 was carried out in the same manner as Example 2, except that instead of PMA as the solvent used in the main agent, Metoace, which has a solubility parameter (SP value) of 8.8, was used as the solvent. Example 5 had a pot life of 58 minutes, a tensile strength ratio of 84% after 4 weeks of alkaline water resistance at 80°C, and good weather resistance, with sufficient pot life throughout the year and excellent alkaline water resistance, eliminating the need for a top coat. The initial physical properties of the cured coating also showed good coating film properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0064] Example 6 Example 6 was carried out in the same manner as Example 2, except that 10 mass % of the 20 mass % of PMA used as the solvent for the base was MC-2000, which has a solubility parameter (SP value) of 7.2 to 7.8. Example 6 had a pot life of 49 minutes, a tensile strength ratio of 78% after 4 weeks of alkaline water resistance at 80°C, and good weather resistance, with sufficient pot life throughout the year and excellent alkaline water resistance, eliminating the need for a top coat. The initial physical properties of the cured coating also showed good coating film properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0065] Comparative Examples 4 and 5 Comparative Examples 4 and 5 were conducted in the same manner as Example 2, except that instead of PMA, MC-2000, with a solubility parameter (SP value) of 7.2 to 7.8, or DMSO, with a solubility parameter (SP value) of 14.5, was used as the base solvent. Comparative Example 4, which used an aprotic solvent with a solubility parameter (SP value) less than 8.0, had a tensile strength ratio of 84% after 4 weeks in alkaline aqueous solution at 80°C, demonstrating good weather resistance. However, its pot life was short at 37 minutes, insufficient for year-round use. Comparative Example 5, which used an aprotic solvent with a solubility parameter (SP value) greater than 14.0, had a pot life of 106 minutes and a tensile strength ratio of 100% after 4 weeks in alkaline aqueous solution at 80°C, demonstrating sufficient year-round use and excellent alkaline resistance. However, cracking occurred during weather resistance testing. Furthermore, the initial physical properties of the cured coating were insufficient for use as a finishing material for sports floors or heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0066] Example 7 Example 7 was carried out in the same manner as Example 5, except that the isocyanate group / aromatic amino group equivalent ratio was set to 1.10. Example 7 had a pot life of 46 minutes, a tensile strength ratio of 76% after 4 weeks of alkaline water resistance at 80°C, and good weather resistance, with sufficient pot life throughout the year and excellent alkaline water resistance, eliminating the need for a top coat. The initial physical properties of the cured coating also showed good coating film properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0067] Example 8 Example 8 was carried out in the same manner as Example 5, except that the isocyanate group / aromatic amino group equivalent ratio was set to 1.50. Example 8 had a pot life of 66 minutes, a tensile strength ratio of 84% after 4 weeks of alkaline water resistance at 80°C, and good weather resistance, with sufficient pot life throughout the year and excellent alkaline water resistance, eliminating the need for a top coat. The initial physical properties of the cured coating also showed good coating film properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0068] Example 9 Example 9 was carried out in the same manner as Example 2, except that 10 mass % of the DINP in the curing agent was replaced with PMA. Example 9 had a pot life of 68 minutes, a tensile strength ratio of 76% after 4 weeks of alkaline water resistance at 80°C, and good weather resistance, with sufficient pot life throughout the year and excellent alkaline water resistance, eliminating the need for a top coat. The initial physical properties of the cured coating also showed good coating film properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0069] Example 10 In Example 10, the NCO / OH equivalent ratio of the base agent was adjusted to an NCO content of 4.70 mass%, and 15 mass% of the DINP in the curing agent was replaced with PMA, and the base agent and curing agent were obtained according to the formulation in Table 3. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Example 10 had a pot life of 45 minutes, a tensile strength ratio of 70% after 4 weeks of alkaline water resistance at 80°C, and good weather resistance, with sufficient pot life throughout the year and excellent alkaline water resistance, eliminating the need for a top coat. The initial physical properties of the cured coating also showed good coating film properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0070] Example 11 In Example 11, the base agent and curing agent were prepared according to the formulation in Table 4. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Example 11, which used 20% by mass of PMA as the solvent, hydrogenated XDI as the isocyanate, and 40% by equivalent of the aliphatic polyester polyol P-2050, had a pot life of 45 minutes, a tensile strength ratio of 85% after 4 weeks of alkaline water at 80°C, and good weather resistance, with sufficient pot life throughout the year, excellent alkaline water resistance, and weather resistance that did not require the application of a top coat. Furthermore, the initial physical properties of the cured coating showed good coating properties suitable for use as a finishing material for sports floors and heavy-duty, two-component, hand-applied urethane waterproofing layers.

[0071] Example 12 In Example 12, the base agent and curing agent were prepared according to the formulation in Table 4. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Example 12, which used 20% by mass of PMA as the solvent and 40% by equivalent of PLACCEL® 220EB, a polycaprolactone polyol, had a pot life of 65 minutes, a tensile strength ratio of 80% after 4 weeks of alkaline water exposure at 80°C, and good weather resistance, providing sufficient pot life throughout the year, excellent alkaline water resistance, and weather resistance that did not require the application of a top coat. Furthermore, the initial physical properties of the cured coating showed good coating properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0072] Example 13 In Example 13, the base agent and curing agent were prepared according to the formulation in Table 4. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Example 13, which used 20% by mass of PMA as the solvent and 20% by equivalent of the aliphatic polycarbonate diol PCDX-208, had a pot life of 70 minutes, a tensile strength ratio of 87% after 4 weeks of alkaline water at 80°C, and good weather resistance, with a pot life sufficient throughout the year, excellent alkaline water resistance, and weather resistance that did not require the application of a top coat. Furthermore, the initial physical properties of the cured coating showed good coating properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0073] Example 14 In Example 14, the base agent and curing agent were prepared according to the formulation in Table 4. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Example 14, which used 20% by mass of PMA as the solvent and 60% by equivalent of the aliphatic polycarbonate diol T5650E, had a pot life of 70 minutes, a tensile strength ratio of 80% after 4 weeks of alkaline water at 80°C, and good weather resistance, with a pot life sufficient throughout the year, excellent alkaline water resistance, and weather resistance that did not require the application of a top coat. Furthermore, the initial physical properties of the cured coating showed good coating properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0074] Example 15 In Example 15, the base agent and curing agent were prepared according to the formulation in Table 4. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Example 15, which used 20% by mass of PMA as the solvent and 60% by equivalent of the aliphatic polycarbonate diol T5650J, had a pot life of 62 minutes, a tensile strength ratio of 82% after 4 weeks of alkaline water treatment at 80°C, and good weather resistance, with a pot life sufficient throughout the year, excellent alkaline water resistance, and weather resistance that did not require the application of a top coat. Furthermore, the initial physical properties of the cured coating showed good coating properties suitable for use as a finishing material for sports floors and heavy-traffic, two-component, hand-applied urethane waterproofing layers.

[0075] Comparative Example 6 In Comparative Example 6, the base agent and curing agent were prepared according to the formulation in Table 4. The base agent and curing agent were mixed in a mass ratio of 1:1 to obtain a urethane coating composition. Comparative Example 6, which used 20% by mass of PMA as a solvent relative to the base resin and 40% by equivalent of PDP-70, an aromatic polyester diol, had a pot life of 81 minutes, a low tensile strength ratio of 63% after 4 weeks of alkaline aqueous immersion at 80°C, and cracks occurred during the weather resistance test.

[0076] Example 16 (Example of a multi-layer structure for heavy traffic) Apply 0.15 kg / m of "Fast-hardening OT Primer M Blue" as a penetrating primer to the surface of the concrete base. 2 , and as a film-enhancing primer, "OT Primer QQ / cement = 3 / 2 to 4 / 1" at 0.15 kg / m 2 The mixture was applied uniformly with a roller so that the thickness was adjusted to 100 μm, and then dried. Next, as a waterproof layer, we used "Ortack Ace," a general-purpose waterproof material that meets the high-elongation JIS standard, at 2.6 kg / m 2 The mixture was applied with a comb trowel and dried. Next, the two-component hand-applied urethane waterproofing composition described in Example 2 was applied as a finishing material at a rate of 1.3 kg / m 2 The mixture was applied with a comb trowel and dried. The fracture energy of the above multi-layer laminate in a low-speed, zero-span substrate crack tracking test was 15.3 J, a satisfactory value for use as a finishing material for sports floors and two-component hand-applied urethane waterproofing layers for heavy foot traffic.

[0077] Comparative Example 7 (Comparative Example of a multi-layer structure for heavy traffic) As a finishing material, we used "Ortack Ace," a general-purpose waterproofing material that meets the high-elongation JIS standard, at 2.6 kg / m 2 The same procedure as in Example 16 was carried out, except that the coating was applied and dried with a comb trowel so that the coating was uniform. As a result, the fracture energy in the low-speed, zero-span substrate crack-following test was 2.9 J, which was an insufficient value for use as a finishing material for sports floors or two-component, hand-applied urethane waterproofing layers for heavy foot traffic.

[0078] Reference example (Example of a multi-layer structure for heavy traffic using reinforcing fabric) In Comparative Example 7, when the glass mesh "Mesh UB" was used as the reinforcing fabric, the fracture energy in the low-speed zero-span base crack followability test was 13.3 J.

[0079] The measurement methods for each evaluation item in Tables 1 to 4 are as follows.

[0080] [NCO (mass%)] Accurately weigh out approximately 1 g of the base compound into a 200 mL Erlenmeyer flask, add 10 mL of 0.5 N di-n-butylamine (toluene solution), 10 mL of toluene, and an appropriate amount of bromphenol blue, then add approximately 100 mL of methanol to dissolve. Titrate this mixture with 0.25 N hydrochloric acid solution. The NCO (mass%) is calculated using the following formula: NCO (mass%) = (blank titration value - 0.5N hydrochloric acid solution titration value) × 4.202 × 0.25N hydrochloric acid solution factor × 0.25 ÷ sample weight

[0081] [Pot life (minutes)] In an air-circulating environmental test chamber at a temperature of 23°C and humidity of 50%, the time from the start of stirring and mixing the base resin and curing agent in a specified ratio until the viscosity reached 60,000 mPa·s at 2 rpm using a BH type viscometer was measured.

[0082] [Available construction time (hours)] In an air-circulating environmental test chamber at a temperature of 23°C and humidity of 50%, the waterproofing material was mixed with the base agent and hardener at a specified ratio and applied at 2 kg / m 2 The time when the adhesive was applied and the work could be started in the next step was measured, even though the adhesive was not completely hardened.

[0083] [Creating coatings for measuring initial physical properties] In accordance with JIS A 6021, the waterproofing material was mixed and stirred at a specified ratio of base agent and hardener in an air-circulating environmental test room at a temperature of 23°C and humidity of 50%. 2 The coating was applied and left to cure for 96 hours at a temperature of 23±2°C and a relative humidity of (50±10)%, then demolded. The coating was then turned over and left to cure for a further 240 hours at a temperature of 23±2°C and a relative humidity of (50±10)% to prepare a coating for measuring initial physical properties.

[0084] [Tensile strength (N / mm 2 )] Measurements were carried out based on JIS A 6021 using coating films for measuring initial physical properties.

[0085] [Elongation at break (%)] Measurements were carried out based on JIS A 6021 using coating films for measuring initial physical properties.

[0086] [Tensile product (N / mm)] Using the above tensile strength and elongation at break, calculations were carried out based on JIS A 6021.

[0087] [JIS D hardness (Type D durometer)] Measurements were carried out based on JIS K 6253 using coating films for measuring initial physical properties.

[0088] [Alkaline water resistance test] Three test pieces were immersed in 400 ml of a 0.1% aqueous solution of special grade sodium hydroxide specified in JIS K 8576 at a temperature of 80°C (23°C in JIS A 6021) saturated with special grade calcium hydroxide specified in JIS K 8575 for 28 days (7 days in JIS A 6021). After immersion, the test pieces were thoroughly rinsed with water and left to stand at a temperature of 23±2°C and a relative humidity of (50±10)% for at least 4 hours. Tests were then carried out in accordance with JIS A 6021 to determine the tensile strength ratio (%) compared to before treatment and the elongation at break (%).

[0089] [Weather resistance test] Using the coating film for measuring initial physical properties, the test piece was stretched from a gauge length of 40 mm to 60 mm based on the JIS A 6021 test for deterioration properties during elongation, and exposed to a xenon weather meter for 500 hours (325 hours according to JIS A 6021), and the presence or absence of surface cracks was observed.

[0090] [Preparation of specimens for low-speed zero-span base crack tracking tests] A 5mm wide slit was made to a depth of 6mm in the longitudinal center of the back of a 400mm x 150mm x 8mm flexible asbestos slate board. A primer was then applied to the surface of the flexible asbestos slate board. After the primer had dried, a urethane waterproofing composition was applied to a thickness of 300mm x 100mm x 2mm (coating thickness). The board was then left to cure for one week in an air-circulating environmental testing chamber at 23°C and 50% humidity, after which it was used as a test specimen.

[0091] [Low speed zero span base crack tracking test] The slit part of the test specimen was broken to create a crack in the asbestos slate flexible board. The test specimen was then set in a tensile testing machine, and both ends of the asbestos slate flexible board were pulled longitudinally at a slow speed of 0.5 mm for 1 minute to measure the distance until breakage (elongation at break (mm)) and the total energy until breakage (fracture energy (J)).

[0092] [Table 1]

[0093] [Table 2]

[0094] [Table 3]

[0095] [Table 4] [Industrial Applicability]

[0096] The composition and application method of the present invention can be suitably used as a two-component hand-applied urethane waterproofing material for sports floors and floors subject to heavy foot traffic.

Claims

1. A two-component hand-applied urethane coating composition comprising a base material containing an isocyanate-terminated prepolymer composed of a polyisocyanate and a polyol, and a curing agent containing an aromatic polyamine and an inorganic filler, the polyisocyanate constituting the isocyanate group-terminated prepolymer in the base resin contains more than 70 equivalent % of aliphatic and / or alicyclic isocyanate, and the NCO content of the base resin is 3.0 mass % to 6.0 mass %, the polyol constituting the isocyanate group-terminated prepolymer in the base resin contains 5 equivalent % to 95 equivalent % of a diol having a molecular weight of 500 or more and 5 equivalent % to 95 equivalent % in total of a diol having a molecular weight of less than 500 and a polyol having three or more functional groups, and 10 equivalent % to 80 equivalent % of the total polyol is an aliphatic polyester polyol and / or an aliphatic polycarbonate polyol; the curing agent comprises greater than 80 equivalent percent of all reactive components being an aromatic polyamine, and greater than 70 equivalent percent of the aromatic polyamine being diethyltoluenediamine; and the curing agent comprises 20% to 80% by weight of an inorganic filler; 5 to 40 parts by mass of a plasticizer is mixed with 100 parts by mass of the isocyanate group-terminated prepolymer in the base compound as a curing agent, or as both the base compound and the curing agent, A solvent is blended into the base agent and / or curing agent in an amount of 5% by mass to 40% by mass based on the urethane coating composition, and the solvent contains more than 30% by mass of an aprotic solvent having a solubility parameter (SP value) of 8.0 to 14.0; A two-component urethane coating composition for hand application, in which the ratio of the amount of amino groups (milli-equivalents) of the aromatic polyamine to the mass (g) of the plasticizer is 2.0 to 20.

0.

2. 2. The two-component hand-applied urethane coating composition according to claim 1, wherein the equivalent ratio of the isocyanate groups of the base resin to the amino groups of the aromatic polyamine in the curing agent is 0.9 to 1.

5.

3. The urethane coating composition has a cured coating film with a JIS D hardness of 25 or more and a tensile strength of 10 N / mm ２ The two-component hand-applied urethane coating composition according to claim 1 or 2, wherein

4. A method for applying a urethane waterproof coating layer, comprising applying a primer layer, or a primer layer and a urethane waterproofing material layer, to a substrate surface, and then applying the two-component hand-applied urethane coating composition described in claim 1.

Images