Coating resin composition for civil engineering and construction, cured film, coating method for civil engineering and construction structures, method for preventing tile peeling, and structure

Abstract

To provide a resin composition for coating civil engineering construction that has good workability and can form a cured product having good transparency and water whitening resistance.SOLUTION: Provided is a coating resin composition for civil engineering construction, which is a coating resin composition for civil engineering construction that comprises a polyurethane resin (a) having a polycarbonate structure, a water-based medium (b), and a cross-linking agent (c) reactive with an acidic group or a salt thereof, and satisfies at least one of the following conditions A and B. Condition A: the acid value of the nonvolatile matter in the coating resin composition for civil engineering construction is 5 to 17 mgKOH / g. Condition B: the acid value of polyurethane resin (a) having a polycarbonate structure is 5 to 22 mgKOH / g.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a coating resin composition for civil engineering and architectural use, a cured film, a coating method for civil engineering and architectural structures, a method for preventing tile peeling, and a structure. In particular, the present invention relates to a method for protecting the surface of an exterior wall of a structure having a tiled exterior wall from peeling. [Background technology]

[0002] In recent years, in buildings and other structures with tiles attached to the exterior walls, peeling of tiles due to aging and other factors has become a problem. In addition, concrete fragments have also fallen from concrete structures such as the inner walls of tunnels, highway piers, railway piers, and bridges.

[0003] It is known that tile peeling and the like can be caused by a variety of factors, such as poor installation, damage to the tile or base mortar due to impacts such as earthquakes or collisions, deterioration of the base mortar due to deterioration factors seeping into the exterior wall surface between the tile joints, and mortar peeling due to differences in shrinkage rates relative to the building frame. The scale of peeling accidents ranges from small scale, such as tiles falling due to loose ceramic pieces, to large scale, such as the entire base mortar peeling off.

[0004] In order to prevent such tile peeling, various methods are known for buildings and the like where tiles are attached to the exterior wall surfaces. For example, a method of providing a transparent resin layer on the exterior wall surface to maintain the appearance of the tile finish is known. As such a method, Patent Document 1 describes providing a transparent resin layer by applying an organic solvent-based resin composition to the exterior wall surface of a structure. However, the use of an organic solvent-based resin composition is undesirable from the standpoint of safety, such as fire hazards and workers inhaling the organic solvent, and there is a tendency for complaints about odors, particularly from residents of apartment buildings and the like, to become frequent.

[0005] For the above reasons, there is a demand for the use of waterborne resin compositions rather than organic solvent-based resin compositions for exterior wall surface protection. Patent Document 2 describes applying a waterborne resin composition to the exterior wall surface of a structure. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-069160 [Patent Document 2] Japanese Patent Application Publication No. 2019-035240 Summary of the Invention [Problem to be solved by the invention]

[0007] The aqueous resin composition described in Patent Document 2 uses a metallic crosslinking agent as a crosslinking agent to obtain a cured film with sufficient tensile elongation. However, when the cured film obtained from such an aqueous resin composition is used for an exterior wall that may be exposed to high temperature and humid conditions, particularly in the sun, the cured film may not have sufficient water whitening resistance.

[0008] Furthermore, when conventional aqueous resin compositions are adjusted to the required viscosity to obtain good coatability, whitening of the coating film or cured film obtained by applying the aqueous resin composition may progress due to components in the aqueous resin composition. Therefore, with conventional aqueous resin compositions, there are currently only a limited number of construction methods that offer ease of application and satisfactory performance, particularly in applications for preventing tile peeling, which require high functionality in maintaining appearance.

[0009] An object of the present invention is to provide a resin composition for coating civil engineering and architectural structures that has good workability and is capable of forming a cured product having good transparency and water whitening resistance. Another object of the present invention is to provide a cured film, a method for coating civil engineering and architectural structures, a method for preventing tile peeling, and a structure using such a resin composition for coating civil engineering and architectural structures. [Means for solving the problem]

[0010] One aspect of the present invention relates to a coating resin composition for civil engineering and construction (hereinafter, sometimes simply referred to as a "resin composition"). The resin composition comprises a polyurethane resin (a) having a polycarbonate structure (hereinafter, sometimes simply referred to as a "polyurethane resin (a)"), an aqueous medium (b), and a crosslinking agent (c) reactive with an acidic group or a salt thereof (hereinafter, sometimes simply referred to as a "crosslinking agent (c)"). The resin composition satisfies at least one of the following conditions A and B: Condition A: The acid value of the nonvolatile matter in the resin composition is 5 to 17 mgKOH / g. Condition B: The acid value of the polyurethane resin (a) is 5 to 22 mgKOH / g.

[0011] The resin composition can be dried at room temperature to evaporate low-boiling components, including the aqueous dispersion medium, to form a cured product. During this process, the polyurethane resin (a) and the crosslinking agent (c) react to form crosslinks in the cured product, strengthening it and reducing its acid value, resulting in a cured product with excellent water resistance. Furthermore, the resin composition can suppress whitening of the cured film by ensuring that at least one of the acid values of the nonvolatile components in the resin composition and the polyurethane resin (a) is within a predetermined range. Furthermore, the resin composition has a sufficient pot life, free from the limitations imposed by two-component materials and the risk of poor curing due to inconsistent blending ratios. Therefore, the resin composition can be suitably used for various shapes, such as uneven or angular portions on the surface of a substrate (e.g., concrete).

[0012] Preferred embodiments of the resin composition are shown below. A plurality of these preferred embodiments can be combined. (1) Both conditions A and B must be met. (2) The polyurethane resin (a) has an acidic group. (3) The polyurethane resin (a) has a structure derived from a linear aliphatic diol in the polycarbonate structure of the polyurethane resin (a). (4) The polyurethane resin (a) has a structure derived from an aliphatic polyisocyanate. (5) The crosslinking agent (c) contains a compound having a carbodiimide group. (6) The resin composition further contains a thixotropy-imparting agent (e), and the content of the thixotropy-imparting agent (e) is 20 mass % or less based on the total amount of nonvolatile components of the resin composition. (7) The viscosity of the resin composition is 6.0 to 60 Pa·s, as measured in accordance with JIS-Z8803:2011 (Method for measuring viscosity of liquids) using an E-type viscometer with a 3°×R9.7 cone rotor at a rotation speed of 5 rpm and at 23°C. (8) The resin composition is applied and subjected to a sagging test in accordance with ASTM D4400, and the coating thickness of the coating resin composition for civil engineering and construction, which shows no run-in, is 0.75 mm or more. (9) When a coating film formed from the resin composition is cured for 7 days under standard conditions of 23°C and 50% RH to form a cured film, the grip elongation at 23°C based on JIS A 6021:2011, measured on a cured film with a film thickness of 0.3 mm, is 150% or more. (10) When a coating film formed from the resin composition is cured for 7 days under standard conditions of 23°C and 50% RH to form a cured film, the total light transmittance measured for a cured film with a thickness of 0.3 mm is 10% or more. (11) To be used to prevent tile peeling, waterproof buildings, prevent concrete structures from peeling, protect concrete structures, or waterproof concrete slabs.

[0013] Another aspect of the present invention relates to a cured film, the cured film comprising a cured product of the resin composition described above.

[0014] Preferred embodiments of the cured film are shown below. These preferred embodiments can be combined in combination.

[0015] (1) The elongation between grips at 23°C based on JIS A 6021:2011, measured at a film thickness of 0.3 mm, is 150% or more. (2) The total light transmittance measured at a film thickness of 0.3 mm is 10% or more. (3) The haze measured at a film thickness of 0.3 mm is 70% or less.

[0016] Another aspect of the present invention relates to a method for coating a civil engineering or architectural structure, the method comprising the step of applying the above-described resin composition to a civil engineering or architectural structure.

[0017] Another aspect of the present invention relates to a method for preventing tile peeling, the method comprising the steps of fixing a surface of an existing tiled exterior wall with metal anchors and covering the exterior wall surface with a coating layer, the coating layer including a layer containing a cured product of the resin composition described above.

[0018] Another aspect of the present invention relates to a structure, comprising an exterior wall structure including tiles and a coating layer provided on the exterior wall structure.

[0019] One embodiment of the coating layer includes a layer containing a cured product of the resin composition. Another embodiment of the coating layer includes a first layer and a second layer in this order from the outer wall structure. Here, the first layer is a resin layer of any of acrylic resin, acrylic styrene resin, urethane resin, epoxy resin, and vinyl acetate resin. The second layer is a layer containing a cured product of the resin composition. In this embodiment, the coating layer may further include a third layer, which is a resin layer of any of urethane resin, fluororesin, and acrylic silicone resin, on the second layer opposite to the first layer. Another embodiment of the coating layer includes a second layer and a third layer in this order from the outer wall structure.

[0020] The structure may further comprise metal anchors that hold tiles and / or coating layers included in the exterior wall structure. [Effects of the Invention]

[0021] The present invention provides a resin composition for coating civil engineering and architectural structures that has good workability and is capable of forming a cured product having good transparency and water whitening resistance. The present invention also provides a cured film, a method for coating civil engineering and architectural structures, a method for preventing tile peeling, and a structure using the resin composition for coating civil engineering and architectural structures. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0023] As used herein, the term "for civil engineering and construction" in the context of a coating resin composition for civil engineering and construction means that the coating resin composition is used in the civil engineering field, for example, for bridges, elevated roads, dams, tunnels, roads, land development, etc.; and in the architectural field, for example, for buildings, condominiums, houses, etc. As used herein, the "coating resin composition for civil engineering and construction" can be used, for example, for coatings, paints (top coats, intermediate coats, primer coats, etc.), primers, top coats, paints, sprays, varnishes, etc.

[0024] <Coating resin composition for civil engineering and construction> A coating resin composition for civil engineering and construction (resin composition) according to one embodiment contains a polyurethane resin (a), an aqueous medium (b), and a crosslinking agent (c). The resin composition satisfies at least one of the following conditions A and B, and preferably satisfies both conditions A and B. Condition A: The acid value of the nonvolatile matter in the resin composition is 5 to 17 mgKOH / g. Condition B: The acid value of the polyurethane resin (a) is 5 to 22 mgKOH / g.

[0025] [Polyurethane resin (a) having a polycarbonate structure] The polyurethane resin (a) preferably has a polyol-derived structure and a polyisocyanate-derived structure, and has an acidic group (an acidic group structure). When the polyurethane resin (a) has an acidic group having a predetermined acid value, it tends to be easy to obtain a resin composition that has good workability and can form a cured product having good transparency and water whitening resistance.

[0026] The polyurethane resin (a) may be used singly or in combination of two or more types, as long as it has a polycarbonate structure. When two or more polyurethane resins (a) are used in combination, the polyurethane resins (a) as a whole should satisfy the acid value requirement of condition B, and a polyurethane resin (a) that does not satisfy the acid value requirement of condition B alone (a polyurethane resin with an acid value of less than 5 mg KOH / g or more than 22 mg KOH / g) can be used in combination.

[0027] The polyurethane resin (a) may have, for example, a structure derived from a polyol, a structure derived from a polyisocyanate, and an acidic group-containing polyol.

[0028] (Polyol-derived structure) In this embodiment, the polyol-derived structure in the polyurethane resin (a) refers to a partial structure of the molecular structure of the polyol other than the group involved in the polyurethane-forming reaction. The polyol-derived structure may have a structure derived from a polycarbonate polyol. The polyol-derived structure may be a structure derived from a polyol that does not contain an acidic group.

[0029] The structure derived from a polycarbonate polyol refers to a partial structure of the molecular structure of the polycarbonate polyol other than the group involved in the urethanization reaction. The structure of the polyurethane resin (a) may contain structures derived from multiple types of polyols for the polycarbonate polyol.

[0030] Examples of polycarbonate polyols that introduce a polycarbonate polyol-derived structure into polyurethane resin (a) include polycarbonate polyols having a structure derived from a polyol of a linear aliphatic diol, a branched aliphatic diol, or an alicyclic diol. The structure derived from a polyol of a linear aliphatic diol, a branched aliphatic diol, or an alicyclic diol refers to a partial structure of a polyol molecule of a linear aliphatic diol, a branched aliphatic diol, or an alicyclic diol other than the group involved in the carbonation reaction.

[0031] Examples of the straight-chain aliphatic diol include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, etc. The straight-chain aliphatic diol is preferably a straight-chain aliphatic diol having 4 to 9 carbon atoms, more preferably 6 carbon atoms.

[0032] Examples of branched aliphatic diols include 2-methyl-1,3-propanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, and 2-methyl-1,9-nonanediol.

[0033] Examples of the alicyclic aliphatic diol include 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,3-cyclopentanediol, and 1,4-cycloheptanediol.

[0034] Among these, linear aliphatic diols, because they do not contain a tertiary carbon, tend to generate fewer radicals due to C-H bond cleavage when irradiated with light, etc. Furthermore, linear aliphatic diols tend to lower the glass transition temperature of the polyurethane resin (a) and improve film-forming properties when dried at room temperature. For these reasons, the polycarbonate polyol is preferably a polycarbonate polyol having a structure derived from a linear aliphatic diol, more preferably a polycarbonate polyol having a structure derived from a linear aliphatic diol having 4 to 9 carbon atoms, and even more preferably a polycarbonate polyol having a structure derived from a linear aliphatic diol having 6 carbon atoms.

[0035] The number-average molecular weight of the polycarbonate polyol can be adjusted appropriately depending on the purpose, but is preferably 200 to 5,000, more preferably 200 to 4,000, and even more preferably 300 to 3,000. By setting the number-average molecular weight of the polycarbonate polyol within this range, the polycarbonate polyol becomes easier to handle, and the low-temperature properties of the polyurethane resin derived from the polycarbonate polyol tend to be improved. The number-average molecular weight refers to the number-average molecular weight calculated based on the hydroxyl value measured in accordance with JIS K 1557-1:2007. Specifically, the hydroxyl value of the polycarbonate polyol is measured, and the hydroxyl value is calculated using the terminal group determination method using the formula (56.1 × 1000 × valence) / hydroxyl value. In this formula, the unit of hydroxyl value is [mgKOH / g], and the valence is the number of hydroxyl groups per molecule.

[0036] The polyol-derived structure may have a structure derived from a polyol other than a polycarbonate polyol in addition to a structure derived from a polycarbonate polyol. Examples of polyols other than a polycarbonate polyol include linear or branched aliphatic polyols having 2 to 10 carbon atoms, aliphatic polyols having an alicyclic structure having 6 to 12 carbon atoms, polyester polyols, polyether polyols, polycarbonate polyester polyols, polyoxyalkylene polyols, polyesteramide polyols, polyether-polyester polyols, poly(meth)acrylic polyols, and (hydrogenated) polybutadiene polyols.

[0037] (Polyisocyanate-derived structure) In the present embodiment, the polyisocyanate-derived structure in the polyurethane resin (a) refers to a partial structure of the molecular structure of the polyisocyanate other than the groups involved in the polyurethane-forming reaction.

[0038] Examples of polyisocyanates for introducing a polyisocyanate-derived structure into the polyurethane resin (a) include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and 2,6-diisocyanatomethyl caproate. aliphatic polyisocyanates such as bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate; isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate; Aliphatic polycyanates with alicyclic structures such as 2,5-norbornane diisocyanate, 2,6-norbornane diisocyanate, etc.; 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, 4,4'-diphenylenemethane diisocyanate (MDI) , 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, m-isocyanatophenylsulfonyl isocyanate, p-isocyanatophenylsulfonyl isocyanate, and other aromatic polyisocyanates having an aromatic structure.

[0039] Among these, a structure derived from a polyisocyanate is preferably a structure derived from an aliphatic polyisocyanate, since it is less likely to yellow due to light irradiation. A structure derived from a polyisocyanate is preferably a structure derived from an aliphatic polyisocyanate having an alicyclic structure, more preferably a structure derived from a polyisocyanate having an asymmetric structure, and even more preferably a structure derived from isophorone diisocyanate, since the structure derived from a polyisocyanate prevents crystallization of the polyurethane resin (a) and exhibits stable physical properties over the long term.

[0040] (Structure derived from acidic group-containing polyol) In this embodiment, the structure derived from an acidic group-containing polyol refers to a partial structure of the molecular structure of the acidic group-containing polyol other than the group involved in the polyurethane-forming reaction. Examples of polyols that introduce a structure derived from an acidic group-containing polyol into polyurethane include polyol compounds having at least one acidic group in the molecule. The acidic group is not particularly limited, and examples include a carboxy group, a sulfonyl group, a phosphate group, and a phenolic hydroxyl group. The structure derived from an acidic group-containing polyol is preferably a structure derived from a carboxylic acid group-containing polyol.

[0041] The type of acidic group-containing polyol is not particularly limited, but specific examples include dimethylolalkanoic acids such as 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid, N,N-bishydroxyethylglycine, N,N-bishydroxyethylalanine, 3,4-dihydroxybutanesulfonic acid, and 3,6-dihydroxy-2-toluenesulfonic acid. Among these, alkanoic acids having 4 to 12 carbon atoms and two methylol groups (dimethylolalkanoic acids) are preferred from the viewpoint of availability. Among these, the acidic group-containing polyol is preferably dimethylolalkanoic acid, more preferably 2,2-dimethylolpropionic acid or 2,2-dimethylolbutanoic acid, and even more preferably 2,2-dimethylolpropionic acid, because of its excellent reactivity with crosslinking agents. The structure of the polyurethane resin (a) may contain structures derived from multiple types of acidic group-containing polyols.

[0042] (Properties of polyurethane resin (a)) In the polyurethane resin (a) of this embodiment, the sum of the urethane bonds and urea bonds in the polyurethane resin (a) is preferably 20 to 40 mass %, more preferably 20 to 30 mass %, and even more preferably 20 to 26 mass %, based on the total amount of the polyurethane resin (a). When the sum is within this range, the adhesion between the coating film (or cured film) formed from the resin composition and the substrate tends to be higher, and the mechanical properties such as elastic modulus and stress of the cured film derived from the resin composition tend to be better.

[0043] The total content ratio of urethane bonds and urea bonds can be controlled by the molecular weights of the polyisocyanate, polyol, acidic group-containing polyol, and chain extender, the number of hydroxyl groups, isocyanato groups, and amino groups in one molecule, and the proportion of each raw material used in polyurethane resin (a).

[0044] The acid value (mgKOH / g) of the polyurethane resin (a) can be determined by JIS K5601:1999 Acid Value (Titration Method). In this analytical method, the titrant, solvent, etc. can be appropriately selected depending on the components in the resin composition. Alternatively, the acid value of the polyurethane resin (a) may be calculated based on the following formula instead of this analytical method. Acid value of polyurethane resin (a) (mgKOH / g) = molar amount of acidic groups (carboxylic acid groups) in polyurethane resin (a) (mmol) ÷ polyurethane resin (a) (g) × 56.1

[0045] The acid value of the polyurethane resin (a) may be 5 to 22 mgKOH / g (Condition B). When two or more polyurethane resins (a) are used in combination, the acid value of the polyurethane resin (a) refers to the acid value of the entire polyurethane resin (a). When the acid value of the polyurethane resin (a) is 5 mgKOH / g or more, the polyurethane resin (a) tends to be more easily dispersed in an aqueous medium. When the acid value of the polyurethane resin (a) is 22 mgKOH / g or less, water resistance tends to be improved. When the acid value of the polyurethane resin (a) exceeds 22 mgKOH / g, a low-molecular-weight diol is generally used to introduce acidic groups. Therefore, the amount of hard segments increases, the resin becomes hard, and the elongation decreases, which tends to result in a decrease in out-of-plane bending performance. The acid value of the polyurethane resin (a) is preferably 7 to 22 mgKOH / g, more preferably 10 to 20 mgKOH / g.

[0046] The acid value of the polyurethane resin (a) can be adjusted, for example, by adjusting the amount of acidic groups introduced, or by combining polyurethane resins (a) with different acid values.

[0047] The weight-average molecular weight of the polyurethane resin (a) is preferably 25,000 to 10,000,000, more preferably 50,000 to 5,000,000, and even more preferably 100,000 to 1,000,000. The weight-average molecular weight is measured by gel permeation chromatography (GPC), and a converted value obtained from a previously prepared calibration curve of standard polystyrene can be used. When the weight-average molecular weight is 25,000 or more, a good coating film tends to be obtained by drying the resulting resin composition containing the polyurethane resin (a). When the weight-average molecular weight is 10,000,000 or less, the drying properties of the resin composition tend to be improved.

[0048] The content of polyurethane resin (a) is preferably 10 to 99% by mass, more preferably 30 to 90% by mass, based on the total amount of nonvolatile content of the resin composition. In this specification, the nonvolatile content of the resin composition can be determined by a known method, for example, the heating residue method specified in JIS K5601-1-2:2008.

[0049] In addition to the polyurethane resin (a), the resin composition of this embodiment may also contain a polyurethane resin (a') (hereinafter simply referred to as "polyurethane resin (a')") that does not have a polycarbonate structure. The polyurethane resin (a') has a different polyol-derived structure from the polyurethane resin (a), and the polyol-derived structure does not have a polycarbonate polyol-derived structure. Examples of polyols for introducing such polyol-derived structures into the polyurethane resin (a') include polyester polyols, polyether polyols, polycarbonate polyester polyols, polyoxyalkylene polyols, polyesteramide polyols, polyether-polyester polyols, poly(meth)acrylic polyols, and (hydrogenated) polybutadiene polyols.

[0050] The content of the polyurethane resin (a') is preferably 0 to 90 mass %, more preferably 0 to 50 mass %, based on the total amount of nonvolatile components of the resin composition.

[0051] [Aqueous medium (b)] Examples of the aqueous medium (b) include tap water, ion-exchanged water, distilled water, and ultrapure water. Among these, ion-exchanged water is preferred as the aqueous medium (b) from the viewpoints of availability and suppressing particle destabilization due to the influence of salts. The aqueous medium (b) may also be a mixture of water and a water-miscible organic solvent. Examples of such organic solvents include alcohol solvents such as methanol, ethanol, n-propanol, and isopropanol; ketone solvents such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol, and propylene glycol; alkyl ether solvents of polyalkylene glycols; and lactam solvents such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone. A plurality of aqueous media (b) may be used in combination.

[0052] The content of the aqueous medium (b) is preferably 10 to 90% by mass, and more preferably 20 to 80% by mass, based on the total amount of the polyurethane resin (a) and the aqueous medium (b).

[0053] (Aqueous polyurethane resin dispersion) The polyurethane resin (a) of this embodiment can be suitably in the form of an emulsion or dispersion in which the polyurethane resin (a) is dispersed in the form of fine particles in an aqueous medium (b) (hereinafter, this may be referred to as an "aqueous polyurethane resin dispersion" or "PUD"). When such an aqueous polyurethane resin dispersion is used, the resin composition can be said to contain the aqueous polyurethane resin dispersion containing the polyurethane resin (a) and the aqueous medium (b), and the crosslinking agent (c).

[0054] Methods for dispersing polyurethane resin (a) in an aqueous medium (b) include a self-emulsification method in which a structure derived from an acidic group-containing polyol is introduced into polyurethane resin (a) and neutralized with an amine or the like, or a forced emulsification method using an external emulsifier. These are classified as cationic, anionic, or nonionic depending on the polarity of the acidic group. The self-emulsification method is preferred for dispersing polyurethane resin (a) in an aqueous medium (b) because there is less concern about bleed-out due to low-molecular-weight emulsifiers. Anionic dispersants, particularly those using carboxy groups, are also preferred because they can reduce the concentration of carbonyl groups (acid value) using the crosslinker (c) described below, thereby reducing the amount of hydrophilic groups in the cured film and improving water resistance.

[0055] (Method for producing aqueous polyurethane resin dispersion) The aqueous polyurethane resin dispersion of the present embodiment contains a polyurethane resin (a) having a structure derived from the polyol, a structure derived from the polyisocyanate, and a structure derived from the acidic group-containing polyol, and an aqueous medium (b) for dispersing the polyurethane resin (a).

[0056] The aqueous polyurethane resin dispersion may be, for example, a step (α) of reacting the polyol, the polyisocyanate, and the acidic group-containing polyol to obtain a polyurethane prepolymer; a step (β) of neutralizing the acidic groups of the polyurethane prepolymer; a step (γ) of dispersing the neutralized polyurethane prepolymer in an aqueous medium; a step (δ) of reacting the isocyanato group of the polyurethane prepolymer with a chain extender to obtain an aqueous polyurethane resin; It can be produced by a method comprising:

[0057] The step (α) is preferably carried out by adding at least one type of aqueous organic solvent to the reaction system. The type of aqueous organic solvent is not particularly limited as long as it is a liquid that is soluble in water and does not inhibit the urethanization reaction. Specific examples include alkyl ether solvents of polyalkylene glycols such as dipropylene glycol dimethyl ether, and lactams such as N-ethylpyrrolidone.

[0058] The step (β) of neutralizing the acidic groups of the polyurethane prepolymer and the step (γ) of dispersing the polyurethane prepolymer in an aqueous medium may be carried out simultaneously, and the step (γ) of dispersing the polyurethane prepolymer in an aqueous medium and the step (δ) of reacting it with a chain extender to obtain an aqueous polyurethane resin may be carried out simultaneously.

[0059] The method for dispersing the polyurethane prepolymer in the aqueous medium (b) in step (γ) is not particularly limited, but can be achieved by adding the polyurethane prepolymer or a polyurethane prepolymer solution to the aqueous medium (b) while stirring it with a homomixer or homogenizer. Alternatively, the aqueous medium may be added to the polyurethane prepolymer solution to disperse it. In this case, the proportion of the polyurethane prepolymer is preferably 5 to 60 mass %, more preferably 20 to 50 mass %, based on the total amount of the polyurethane prepolymer and the aqueous medium.

[0060] (Polyurethane prepolymer) The polyurethane prepolymer of this embodiment is obtained by reacting the polyol, the polyisocyanate, and the acidic group-containing polyol. The ratio of the number of moles of isocyanato groups of the polyisocyanate compound to the total number of moles of hydroxyl groups of the polyol and the acidic group-containing polyol is preferably 1.1 to 2.5, more preferably 1.2 to 2.2, and even more preferably 1.3 to 2.0.

[0061] A catalyst may be used when the polyol and the acidic group-containing polyol are reacted with the polyisocyanate to obtain the polyurethane prepolymer.

[0062] The catalyst is not particularly limited, and examples thereof include salts of metals with organic or inorganic acids, such as tin-based catalysts (trimethyltin laurate, dibutyltin dilaurate, etc.) and lead-based catalysts (lead octoate, etc.); organometallic derivatives; amine-based catalysts (triethylamine, N-ethylmorpholine, triethylenediamine, etc.); diazabicycloundecene-based catalysts, etc. Among these, dibutyltin dilaurate is preferred from the viewpoint of reactivity.

[0063] The reaction of the polyol and acidic group-containing polyol with the polyisocyanate may be carried out without solvent or with the addition of an organic solvent. Examples of organic solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dioxane, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, N-ethylpyrrolidone, ethyl acetate, diethylene glycol butyl ether, and dipropylene glycol monomethyl ether. Among these, acetone, methyl ethyl ketone, or ethyl acetate is preferred as the organic solvent because it allows the polyurethane prepolymer to be dispersed in water, subjected to a chain extension reaction, and then removed by heating under reduced pressure. Furthermore, N-methylpyrrolidone, N-ethylpyrrolidone, or dipropylene glycol monomethyl ether is preferred because it functions as a film-forming aid when forming a coating film from the resulting aqueous polyurethane resin dispersion.

[0064] (Neutralizer) In order to disperse the polyurethane prepolymer in water, a basic component can be added to the polyurethane prepolymer solution to neutralize the acid groups derived from the acid group-containing polyol contained in the polyurethane prepolymer.

[0065] Examples of basic components that can be used for neutralization include organic amines such as trimethylamine, triethylamine, triisopropylamine, tributylamine, triethanolamine, N-methyldiethanolamine, N-phenyldiethanolamine, dimethylethanolamine, diethylethanolamine, N-methylmorpholine, and pyridine, inorganic alkalis such as sodium hydroxide and potassium hydroxide, and ammonia. Among these, the basic component is preferably an organic amine, and among organic amines, triethylamine is preferred.

[0066] The basic component is preferably added to the polyurethane prepolymer solution directly or as an aqueous solution. The amount of the basic component added may be 0.5 to 2 times, preferably 0.7 to 1.5 times, and more preferably 0.85 to 1.3 times the equivalent of the acidic groups in the polyurethane prepolymer. Note that a plurality of these neutralizing agents may be used in combination.

[0067] The content of the aqueous medium (b) in the aqueous polyurethane resin dispersion is preferably 10 to 90 mass %, more preferably 20 to 80 mass %, based on the total amount of the polyurethane resin (a) and the aqueous medium (b).

[0068] (Chain extender) In the production of the aqueous polyurethane resin dispersion, a chain extender can be used to increase the molecular weight.

[0069] The chain extender to be used can be appropriately selected depending on the purpose or application, and examples thereof include water; ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,10-decanediol, 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, xylylene glycol, bis(p-hydroxy)diphenyl, bis(p-hydroxyphenyl)propane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, ... low molecular weight polyols such as 1,1-bis[4-(2-hydroxyethoxy)phenyl]sulfone and 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane; high molecular weight polyols such as polyester polyols, polyester amide polyols, polyether polyols, polyether ester polyols, polycarbonate polyols and polyolefin polyols; and polyamines such as ethylene diamine, isophorone diamine, 2-methyl-1,5-pentanediamine, aminoethylethanolamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine and pentaethylene hexamine.

[0070] For chain extenders, see, for example, "Latest Polyurethane Application Technology" (CMC Corporation, 1985), and for polymer polyols, see, for example, "Polyurethane Foam" (Kobunshi Kankokai, 1987).

[0071] Multiple types of chain extenders may be used in combination. The temperature for the reaction between the polyurethane prepolymer and the chain extender is 0 to 50°C, preferably 0 to 40°C, and the reaction time, which varies depending on the reaction temperature, is, for example, 0.1 to 5 hours, preferably 0.2 to 3 hours.

[0072] The amount of chain extender added is preferably equal to or less than the equivalent of the isocyanato group that serves as the chain extension initiation point in the resulting urethane polymer. If the amount of chain extender added is equal to or less than the equivalent of the isocyanato group, it is possible to avoid a decrease in the molecular weight of the urethane polymer obtained by chain extension, which would result in a decrease in the strength of the cured film. The chain extender may be added after or during dispersion of the polyurethane prepolymer in the aqueous medium. Chain extension can also be carried out using water. In this case, the water as the aqueous medium doubles as the chain extender.

[0073] [Crosslinking agent (c) reactive with an acidic group or a salt thereof] The resin composition of this embodiment contains a crosslinking agent (c), which allows the resin composition to be cured and improves the water resistance of the cured film containing the cured product.

[0074] The crosslinking agent (c) is not particularly limited as long as it is a compound reactive with the acidic group (preferably a carboxylic acid group) or a salt thereof of the polyurethane resin (a), but examples thereof include compounds having a carbodiimide group, compounds having an oxazoline group, amino resins, polyisocyanates, blocked polyisocyanates, melamine resins, and polyvalent metal complexes. Among these, the crosslinking agent (c) is preferably a compound having a carbodiimide group, polyisocyanates, blocked polyisocyanates, or polyvalent metal complexes, because they have excellent reactivity with carboxylic acids at room temperature, do not react in the presence of an aqueous medium, and are easily converted into a one-component product. The crosslinking agent (c) is more preferably a compound having a carbodiimide group, because they have excellent water whitening resistance.

[0075] The compound having a carbodiimide group may be, for example, an organic compound having multiple NCN groups in one molecule. Usually, one carbonyl group is bonded to one NCN group, so by having multiple NCN groups, multiple molecules can be bonded to the polyurethane resin (a) to form a crosslink. Examples of organic compounds having multiple NCN groups in one molecule include compounds represented by the following general formula (1):

[0076] [ka]

[0077] In formula (1), R 1 , R 2 , and R 3 represents an organic group, and n represents an integer of 2 or greater. The organic group is preferably a hydrophilic organic group.

[0078] When the polyurethane resin (a) has an acid value and the crosslinking agent (c) is a compound having a carbodiimide group, the resin composition has an equivalent ratio of the carbodiimide group in the crosslinking agent to the acid value in the coating resin composition for civil engineering and construction, calculated by the following formula (B), of preferably 0.1 or more and less than 2.0, more preferably 0.1 or more and less than 1.2, and even more preferably 0.3 or more and less than 1.2. Equivalent ratio = Concentration of crosslinker (c) in the coating resin composition for civil engineering and construction (% by mass) ÷ Carbodiimide group equivalent of crosslinker (c) (g / mol) ÷ Concentration of nonvolatile matter in the coating resin composition for civil engineering and construction (% by mass) ÷ Acid value (mgKOH / g) × 56.1 × 1000 (Equation (B))

[0079] Commercially available compounds containing a carbodiimide group include the Carbodilite series manufactured by Nisshinbo Chemical Inc. Specific product names include, for example, water-soluble types "SV-02," "V-02," "V-02-L2," and "V-04"; emulsion types "E-01," "E-02," and "E-05"; organic solution types "V-01," "V-03," "V-07," and "V-09"; and solventless type "V-05." Among these, it is preferable to use "E-05," which has excellent long-term storage stability.

[0080] Compounds having an oxazoline group are generally obtained by polymerizing addition-polymerizable oxazolines such as 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, and 2-isopropenyl-2-oxazoline. The compounds having an oxazoline group may be copolymerized with other monomers as needed. The polymerization method for obtaining the compounds having an oxazoline group is not particularly limited, and known polymerization methods can be used. Commercially available compounds having an oxazoline group include the Epocross series manufactured by Nippon Shokubai Co., Ltd. Specific product names include, for example, water-soluble types "WS-500" and "WS-700"; emulsion types "K-1010E," "K-1020E," "K-1030E," "K-2010E," "K-2020E," and "K-2030E."

[0081] Examples of the amino resin include partially or fully methylolated amino resins obtained by reacting an amino component with an aldehyde component. Examples of the amino component include melamine, urea, benzoguanamine, acetoguanamine, steroguanamine, spiroguanamine, and dicyandiamide. Examples of the aldehyde component include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde.

[0082] Examples of polyisocyanates include compounds having two or more isocyanate groups in one molecule, such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate.

[0083] The blocked polyisocyanate may be obtained by adding a blocking agent to the isocyanate group of the polyisocyanate. Examples of the blocking agent include phenol-based agents such as phenol and cresol, aliphatic alcohol-based agents such as methanol and ethanol, active methylene-based agents such as dimethyl malonate and acetylacetone, mercaptan-based agents such as butyl mercaptan and dodecyl mercaptan, acid amide-based agents such as acetanilide and acetic acid amide, lactam-based agents such as ε-caprolactam and δ-valerolactam, acid imide-based agents such as succinimide and maleimide, oxime-based agents such as acetaldoxime, acetoneoxime and methylethylketoxime, and amine-based agents such as diphenylaniline, aniline and ethyleneimine.

[0084] Examples of the melamine resin include methylol melamines such as dimethylol melamine and trimethylol melamine; alkyl ethers or condensates of these methylol melamines; and condensates of alkyl ethers of methylol melamine.

[0085] Examples of polyvalent metal complexes include complexes in which one or more ligands such as ammonium ions, hydroxide ions, carbonate ions, acetate ions, tartrate ions, or malate ions are bound to a divalent or higher metal ion such as calcium, magnesium, zinc, aluminum, titanium, or zirconium.

[0086] The content of the crosslinking agent (c) is preferably 0.1 to 50 mass %, and more preferably 2.0 to 10 mass %, based on the total amount of nonvolatile content of the resin composition.

[0087] The resin composition of the present embodiment may further contain a weather resistance imparting agent (d), a thixotropy imparting agent (e), a thickener, a resin other than the polyurethane resin (a) and the polyurethane resin (a'), other components, and the like.

[0088] The weather resistance imparting agent (d) may be, for example, at least one selected from the group consisting of hydroxyphenyltriazine derivatives and hindered amine derivatives. By further including the weather resistance imparting agent (d) in the resin composition, the mechanical strength and weather resistance of the cured film can be simultaneously achieved at higher levels.

[0089] Hydroxyphenyltriazine derivatives can improve the weather resistance of cured products by absorbing ultraviolet rays in sunlight. Hydroxyphenyltriazine derivatives are less likely to bleed out from cured products than general benzophenone-type ultraviolet absorbers and benzotriazole-type ultraviolet absorbers, and therefore can maintain the weather resistance of cured products for a long period of time.

[0090] Examples of hydroxyphenyltriazine derivatives include a mixture of 2-[4-(2-hydroxy-3-dodecyloxypropyl)oxy-2-hydroxyphenyl]-4,6-[bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-(2-hydroxy-3-tridecyloxypropyl)oxy-2-hydroxyphenyl]-4,6-[bis(2,4-dimethylphenyl)-1,3,5-triazine (manufactured by BASF Japan Ltd., trade name: TINUVIN400). ), 2-[4-(octyl-2-methylethanoate)oxy-2-hydroxyphenyl]-4,6-[bis(2,4-dimethylphenyl)]-1,3,5-triazine (manufactured by BASF Japan Ltd., trade name: TINUVIN 479), tris[2,4,6-[2-{4-(octyl-2-methylethanoate)oxy-2-hydroxyphenyl}]-1,3,5-triazine (manufactured by BASF Japan Ltd., trade name: TINUVIN 777), TINUVIN 477, etc. As the hydroxyphenyltriazine derivative provides excellent weather resistance of the cured product, TINUVIN 400 or TINUVIN 477 is preferred, and TINUVIN 400 is more preferred.

[0091] The hindered amine derivative is a 2,2,6,6-tetraalkylpiperidine derivative having a substituent at the 4-position. Examples of the substituent at the 4-position include an alkyl group, an ester group, an alkoxy group, an alkylamino group, and various other substituents. Since the weather resistance of the cured product is improved when the hindered amine derivative is used in combination with a hydroxyphenyltriazine derivative, it is preferable that the hindered amine derivative has an ester group as the substituent at the 4-position and an alkyl group as the substituent at the N-position. The N-position may also be substituted with an alkyl group, an oxy radical, or the like.

[0092] Examples of hindered amine derivatives include TINUVIN 292, TINUVIN 123, TINUVIN 144, TINUVIN 765, Chimasolv 119FL, Chimasolv 2020FDL, Chimasolv 944, Chimasolv 622LD (trade names, manufactured by BASF Japan Ltd.); Sumisorb 577 (trade name, manufactured by Sumitomo Chemical Co., Ltd.); Adeka STAB LA-52, Adeka STAB LA-57, Adeka STAB LA-62, Adeka STAB LA-67, Adeka STAB LA-63P, Adeka STAB LA-68LD, Adeka STAB LA-82, Adeka STAB LA-87, Adeka STAB LA-503, Adeka STAB LA-601 (trade names, manufactured by ADEKA Corporation); Sanol LS-2626, Sanol LS-744, Sanol LS-440 (trade names, manufactured by Sankyo Co., Ltd.). The hindered amine derivative is preferably TINUVIN292 or TINUVIN123, more preferably TINUVIN123, because the cured product has excellent weather resistance over a long period of time.

[0093] The weather resistance agent (d) may be an aqueous dispersion of at least one selected from the group consisting of hydroxyphenyltriazine derivatives and hindered amine derivatives. Examples of such aqueous dispersions include TINUVIN123-DW(N), TINUVIN400-DW(N), TINUVIN477-DW(N), and TINUVIN5333-DW(N) (product names, manufactured by BASF Japan Ltd.). The aqueous dispersion is preferably TINUVIN123-DW(N) or TINUVIN400-DW(N).

[0094] The content of the weather resistance imparting agent (d) is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, based on the total amount of nonvolatile content of the resin composition. When the content of the weather resistance imparting agent (d) is 0.01% by mass or more, the weather resistance of the cured product tends to be further improved. When the content of the weather resistance imparting agent (d) is 20% by mass or less, bleeding out of the weather resistance imparting agent (d) from the cured product can be sufficiently suppressed, and discoloration of the cured product due to the weather resistance imparting agent can tend to be suppressed. Furthermore, when the content of the weather resistance imparting agent (d) is within the above range, there tends to be an excellent balance between the effect of imparting weather resistance to the cured product and economic efficiency.

[0095] By further containing a thixotropy-imparting agent (e), the resin composition can maintain coatability with a roller or the like while suppressing sagging when applied to inclined and vertical surfaces. The thixotropy-imparting agent (e) may be, for example, finely divided silica. The finely divided silica may be hydrophilic finely divided silica or may be hydrophobized. The hydrophobization treatment can be carried out, for example, by treatment with an alkylsilyl compound. The alkylsilyl compound is preferably dimethylsilyl or trimethylsilyl.

[0096] The finely divided silica can be used in combination with a polyhydroxycarboxylic acid ester derivative, a polycarboxylic acid amide derivative, etc., thereby reducing the amount of finely divided silica added. Examples of polyhydroxycarboxylic acid ester derivatives that can be used include BYK-R 606 (manufactured by BYK Japan, trade name). Examples of polycarboxylic acid amide derivatives that can be used include BYK-405 and BYK-R 605 (manufactured by BYK Japan, trade name).

[0097] The content of the thixotropy-imparting agent (e) is preferably 0 to 20% by mass, based on the total amount of nonvolatile content of the resin composition. Since the acid value of the polyurethane resin (a) is within a predetermined range or the acid value of the nonvolatile content in the resin composition is within a predetermined range, the resin composition of this embodiment can thicken and maintain sufficient viscosity even when the content of the thixotropy-imparting agent (e) is 20% by mass or less. Furthermore, since the content of the thixotropy-imparting agent (e) can be reduced, the transparency of the cured film tends to be improved. The content of the thixotropy-imparting agent (e) is more preferably 1.0 to 15% by mass, and even more preferably 3.0 to 10% by mass, based on the total amount of nonvolatile content of the resin composition.

[0098] By including a thickener in the resin composition, the viscosity of the entire resin composition can be increased, thereby suppressing sagging when applied to inclined and vertical surfaces. Examples of such thickeners include acrylic thickeners such as polyacrylic acid and acrylic copolymers; urethane associative thickeners; alkali-swelling thickeners; copolymer thickeners such as modified polyoxyethylene-urethane block copolymers; cellulose thickeners such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and hydrophobically modified hydroxycellulose; surfactants such as polyethylene glycol ethers and nonionic surfactants; polysaccharides such as alginates, guar gum, and mannan; and water-soluble resins such as polyvinyl alcohol and polyvinylpyrrolidone. The thickener is preferably a urethane associative thickener.

[0099] The content of the thickener is preferably 0 to 20 mass %, more preferably 0.1 to 10 mass %, and even more preferably 0.5 to 2.0 mass %, based on the total amount of nonvolatile content of the resin composition.

[0100] Examples of resins other than the polyurethane resin (a) and the polyurethane resin (a') include acrylic resins, acrylic silicone resins, epoxy resins, alkyd resins, polyolefin resins, and fluororesins. These may be used alone or in combination. The other resins preferably have one or more hydrophilic groups. Examples of hydrophilic groups include hydroxyl groups, carboxyl groups, sulfonic acid groups, and polyethylene glycol groups. The other resins are preferably at least one selected from the group consisting of polyester resins, acrylic resins, and polyolefin resins.

[0101] The acrylic resin is preferably a hydroxyl-containing acrylic resin, which can be produced by copolymerizing a hydroxyl-containing polymerizable unsaturated monomer with another polymerizable unsaturated monomer copolymerizable with the hydroxyl-containing polymerizable unsaturated monomer by a known method, such as solution polymerization in an organic solvent or emulsion polymerization in water.

[0102] The hydroxyl group-containing polymerizable unsaturated monomer is a compound having one or more hydroxyl groups and one or more polymerizable unsaturated bonds in one molecule. Examples of the hydroxyl group-containing polymerizable unsaturated monomer include monoesters of (meth)acrylic acid with dihydric alcohols having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; ε-caprolactone-modified products of these monoesters; N-hydroxymethyl (meth)acrylamide; allyl alcohol; and (meth)acrylates having a polyoxyethylene chain with a hydroxyl group at the molecular terminal.

[0103] Examples of other polymerizable unsaturated monomers include compounds having a polyfunctional polymerizable unsaturated bond, such as trimethylolpropane triacrylate and divinylbenzene.

[0104] The hydroxyl group-containing acrylic resin preferably has an anionic functional group. The hydroxyl group-containing acrylic resin having an anionic functional group can be produced, for example, by using a polymerizable unsaturated monomer having an anionic functional group such as a carboxy group, a sulfonic acid group, or a phosphoric acid group as one type of polymerizable unsaturated monomer.

[0105] The hydroxyl value of the hydroxyl-containing acrylic resin is preferably 1 to 200 mgKOH / g, more preferably 2 to 100 mgKOH / g, and even more preferably 3 to 60 mgKOH / g, from the viewpoints of the storage stability of the resin composition and the water resistance of the cured film.

[0106] Furthermore, when the hydroxyl group-containing acrylic resin has an acidic group such as a carboxy group, the acid value of the hydroxyl group-containing acrylic resin is preferably 1 to 200 mgKOH / g, more preferably 2 to 150 mgKOH / g, and even more preferably 5 to 100 mgKOH / g, from the viewpoint of water resistance of the cured film.

[0107] The acrylic silicone resin is not particularly limited as long as it is, for example, a resin obtained by polymerizing an acrylic silicone monomer together with other polymerizable unsaturated monomers. The acrylic silicone resin is preferably a water-dispersed acrylic silicone resin emulsion.

[0108] Examples of epoxy resins include resins obtained by reacting a bisphenol compound with epichlorohydrin, and examples of bisphenol compounds include bisphenol A and bisphenol F.

[0109] Examples of alkyd resins include alkyd resins obtained by reacting polybasic acids such as phthalic acid, terephthalic acid, and succinic acid with polyhydric alcohols and further with modifiers such as fats and oils, fatty acids (soybean oil, linseed oil, coconut oil, stearic acid, etc.), and natural resins (rosin, amber, etc.).

[0110] Examples of the polyolefin resin include a polyolefin resin obtained by polymerizing or copolymerizing an olefinic monomer with other monomers according to a conventional polymerization method, and dispersing the resulting polyolefin resin in water using an emulsifier, or a resin obtained by emulsion polymerizing an olefinic monomer with other monomers. The polyolefin resin may be a chlorinated polyolefin-modified resin.

[0111] Examples of olefin-based monomers include α-olefins such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-hexene, 1-decene, and 1-dodecene; and conjugated or non-conjugated dienes such as butadiene, ethylidene norbornene, dicyclopentadiene, 1,5-hexadiene, and styrenes. A plurality of these monomers may be used in combination.

[0112] Examples of other monomers copolymerizable with the olefin-based monomer include vinyl acetate, vinyl alcohol, maleic acid, citraconic acid, itaconic acid, maleic anhydride, citraconic anhydride, and itaconic anhydride. Two or more of these monomers may be used in combination.

[0113] The fluororesin is not particularly limited as long as it is, for example, a polymer of a fluorine-containing olefin with other monomers as appropriate, and is preferably a water-dispersible fluororesin emulsion.

[0114] The content of resins other than polyurethane resin (a) and polyurethane resin (a') is preferably 0 to 90 mass%, more preferably 0 to 50 mass%, based on the total amount of the resin composition and the total amount of non-volatile components of the resin composition.

[0115] Other components that can be used include additives such as film-forming aids, antifoaming agents, wetting and dispersing agents, surfactants, pigments, dyes, inorganic fillers, antioxidants, hardening regulators, metal deactivators, antiozonants, lubricants, anti-termite agents, and anti-fungal agents.

[0116] The content of the other components is preferably 0 to 90 mass %, more preferably 0 to 50 mass %, based on the total amount of the resin composition.

[0117] The resin composition of the present embodiment can be obtained by mixing the polyurethane resin (a) (aqueous polyurethane resin dispersion) and the crosslinking agent (c), and, if necessary, the weather resistance imparting agent (d), the thixotropy imparting agent (e), resins other than the polyurethane resin (a) and the polyurethane resin (a'), and other components, for example, using a disper, ball mill, SG mill, roll mill, planetary mixer, or the like.

[0118] The acid value of the nonvolatile content in the resin composition of this embodiment may be 5 to 17 mgKOH / g (Condition A). When the acid value of the nonvolatile content in the resin composition is 5 mgKOH / g or more, the repulsive force of the emulsion particles can prevent aggregation and precipitation between particles, tending to ensure storage stability. When the acid value of the nonvolatile content in the resin composition is 17 mgKOH / g or less, the re-emulsification or water swelling of the cured product can be suppressed, tending to ensure water resistance. Furthermore, by having the acid value of the nonvolatile content in the resin composition within the above range, sufficient viscosity can be maintained without increasing the content of the thixotropy-imparting agent (d), and sagging resistance can be imparted. Furthermore, since the above effects can be achieved without increasing the content of the thixotropy-imparting agent (d), the transparency of the cured product tends to be more easily ensured. The acid value of the nonvolatile content in the resin composition is preferably 7 to 17 mgKOH / g, more preferably 10 to 17 mgKOH / g, and even more preferably 13 to 16 mgKOH / g. In this specification, the acid value of the nonvolatile content in the resin composition can be suitably determined by JIS K5601:1999 Acid value (titration method). In this analysis method, the titrant, solvent, etc. can be appropriately selected depending on the components in the resin composition.

[0119] The viscosity of the resin composition of this embodiment at 5 rpm may be 0.05 Pa·s or more, 0.1 Pa·s or more, 1.0 Pa·s or more, 6.0 Pa·s or more, or 10 Pa·s or more. When the viscosity of the resin composition is within this range, sagging tends to be less likely to occur when applied by roller or spray. The viscosity of the resin composition at 5 rpm may be 100 Pa·s or less, 60 Pa·s or less, or 30 Pa·s or less. When the viscosity of the resin composition is within this range, stringiness and the like tend to be less likely to occur when applied by roller or spray, and workability tends to be excellent. The viscosity refers to the viscosity measured at 5 rpm and 23°C using an E-type viscometer with a 3° x R9.7 cone rotor in accordance with JIS-Z8803:2011 (Method for measuring viscosity of liquids).

[0120] The viscosity of the resin composition of this embodiment at 50 rpm may be 0.01 Pa·s or more, 0.5 Pa·s or more, 1.0 Pa·s or more, or 3.0 Pa·s or more. When the viscosity of the resin composition is within this range, sagging tends to be less likely to occur when applied by roller or spray. The viscosity of the resin composition at 50 rpm may be 50 Pa·s or less, 30 Pa·s or less, or 10 Pa·s or less. When the viscosity of the resin composition is within this range, stringing and the like tends to be less likely to occur when applied by roller or spray, and workability tends to be excellent. Note that the viscosity at 50 rpm refers to the viscosity when the viscosity measurement conditions at 5 rpm are changed from a rotation speed of 5 rpm to a rotation speed of 50 rpm.

[0121] The thixotropy index (TI) of the resin composition of this embodiment (viscosity at 5 rpm / viscosity at 50 rpm) may be 1.0 or more, 2.0 or more, or 3.0 or more. When the TI of the resin composition is in this range, the resin composition can be more sufficiently imparted with thixotropy (thixotropy), the occurrence of dripping during coating can be more effectively suppressed, and the resin composition has appropriate leveling properties. When roller coating is performed, no roller pattern remains in the coating film after drying, and a smooth coating film tends to be easily formed.

[0122] The resin composition of this embodiment is applied and subjected to a sagging test based on ASTM D4400. The coating thickness at which the resin composition does not flow may be 0.75 mm or more, 1.0 mm or more, or 1.5 mm or more. When the coating thickness is within this range, application to ceiling surfaces and vertical surfaces tends to be easier.

[0123] The tack-free time of the resin composition of this embodiment may be less than 72 hours, less than 24 hours, or less than 6 hours. If the tack-free time is within this range, for example, when a topcoat is further applied to a coating formed using the resin composition, the time until the topcoat can be applied tends to be further shortened. The tack-free time can be measured in accordance with "5.19 Tack-Free Test" in JIS A1439:2010 "Test Methods for Construction Sealant."

[0124] When a coating film formed from the resin composition of this embodiment is cured for 7 days under standard conditions of 23°C and 50% RH to form a cured film, the grip elongation at 23°C measured on a 0.3 mm thick cured film may be 150% or more, 200% or more, or 250% or more. When the grip elongation of the cured film is within this range, the cured film tends to have better out-of-plane bending resistance. The grip elongation can be measured according to JIS A 6021:2011.

[0125] When a coating film formed from the resin composition of this embodiment is cured for 7 days under standard conditions of 23°C and 50% RH to form a cured film, the total light transmittance measured for the cured film having a thickness of 0.3 mm may be 10% or more, 30% or more, 50% or more, 60% or more, or 80% or more. The total light transmittance can be measured in accordance with JIS K 7375:2008 "Plastics - Determination of total light transmittance and total light reflectance."

[0126] When a coating film formed from the resin composition of this embodiment is cured for 7 days under standard conditions of 23°C and 50% RH to form a cured film, the haze measured for the cured film having a thickness of 0.3 mm may be 70% or less, 50% or less, 30% or less, or 20% or less. The haze can be measured in accordance with JIS K 7136:2000 "Determination of haze for plastics - transparent materials."

[0127] When the total light transmittance and haze measured as described above are simultaneously within the above ranges, the cured film formed from the resin composition of the present embodiment has excellent transparency.

[0128] <Applications of coating resin compositions for civil engineering and construction> The resin composition of the present embodiment can be suitably used for preventing tile peeling, waterproofing of buildings, preventing concrete structures from peeling, protecting concrete structures, waterproofing concrete slabs, and the like.

[0129] The resin composition for preventing tile peeling is, for example, one in which the above-mentioned resin composition is used to prevent tile peeling. Because the resin composition for preventing tile peeling uses the above-mentioned resin composition, the resin composition for preventing tile peeling is excellent in safety during work and application, and can reduce the influence of humidity during application. Furthermore, when the resin composition for preventing tile peeling is used, the number of layers is reduced, which prevents the construction period from being extended. Furthermore, the resin composition for preventing tile peeling is excellent in weather resistance, and a transparent, high-strength cured film can be suitably obtained.

[0130] The resin composition for waterproofing buildings is, for example, one in which the above-mentioned resin composition is used for waterproofing buildings. Because the resin composition for waterproofing buildings uses the above-mentioned resin composition, it is excellent in safety during work and workability, and can reduce the effects of humidity during construction. Furthermore, because the resin composition for waterproofing buildings requires a small number of layers, it can prevent the construction period from being extended. Furthermore, the resin composition for waterproofing buildings has excellent weather resistance and can suitably produce a transparent, high-strength cured film. Because the resin composition for waterproofing buildings uses the above-mentioned resin composition, it becomes a high-strength cured film compared to conventional urethane waterproofing materials, so when used as a waterproofing material for the roof of a building, it can improve the durability of the roof and enable the roof to be used for a variety of purposes.

[0131] The resin composition for preventing spalling of concrete structures is, for example, one in which the above-mentioned resin composition is used to prevent spalling of concrete structures. Because the resin composition for preventing spalling of concrete structures uses the above-mentioned resin composition, it is excellent in safety and workability during work and can reduce the effects of humidity during construction. Furthermore, when the resin composition for preventing spalling of concrete structures is used, the number of layers is reduced, so that the construction period can be prevented from being extended compared to when conventional coating resin compositions are used. Furthermore, the resin composition for preventing spalling of concrete structures is excellent in weather resistance and strength, and a transparent cured film can be obtained. The resin composition for preventing spalling of concrete structures can be applied to the surface of a concrete structure to form a cured film that can prevent concrete pieces from spalling due to deterioration of the structure.

[0132] The resin composition for preventing spalling of concrete structures has the performance described in, for example, the Push-out Test Method for Surface Coating Materials Applied to Prevent Spalling of Concrete Pieces (JSCE-K 533-2013) of the Japan Society of Civil Engineers, or in the Spalling Prevention Measures of the Structure Construction Management Guidelines (July 2017, East Nippon Expressway Company Limited, Central Nippon Expressway Company Limited, West Nippon Expressway Company Limited).

[0133] The resin composition for protecting concrete structures is, for example, one in which the above-mentioned resin composition is used to protect concrete structures. The resin composition for protecting concrete structures uses the above-mentioned resin composition, and therefore is excellent in safety during work and workability, and can reduce the effects of humidity during construction. Furthermore, when the resin composition for protecting concrete structures is used, the number of layers is reduced, which prevents the construction period from being extended. Furthermore, the resin composition for protecting concrete structures is excellent in weather resistance and strength, and can suitably produce a transparent cured film. The resin composition for protecting concrete structures tends to be excellent in protective performance for concrete structures, such as the appearance of the cured film, adhesion to concrete, and blocking properties against deterioration factors (salt blocking, oxygen permeation blocking, water vapor permeation blocking, and carbonation blocking).

[0134] The resin composition for waterproofing slabs of concrete slabs is, for example, one in which the above-mentioned resin composition is used as a resin composition for waterproofing slabs of concrete slabs (for example, a slab waterproofing layer (NEXCO slab waterproofing grade I), a slab waterproofing layer (NEXCO slab waterproofing grade II), an edge protection material, etc.). The resin composition for waterproofing slabs of concrete slabs uses the above-mentioned resin composition, which provides excellent safety during work and ease of application, and can reduce the effects of humidity during application. Furthermore, the resin composition for waterproofing slabs of concrete slabs requires a small number of layers, which can prevent the construction period from being extended. The resin composition for waterproofing slabs of concrete slabs uses the above-mentioned resin composition, which makes it possible to preferably obtain a cured film that is excellent in weather resistance and has high strength.

[0135] The resin composition for waterproofing concrete slabs can form a cured film with higher strength than conventional waterproofing for concrete slabs. Since the resin composition for waterproofing concrete slabs also has excellent weather resistance, when used as a waterproofing layer for concrete slabs (NEXCO waterproofing grade II), the waterproofing for concrete slabs can be used as an edge protection material for the waterproofing for concrete slabs. Furthermore, by using the resin composition for waterproofing for concrete slabs, the waterproofing for concrete slabs and the edge protection material have a seamless structure, providing a structure with excellent waterproofing reliability.

[0136] The resin composition for waterproofing concrete slabs (slab waterproofing layer (NEXCO slab waterproofing grade I), slab waterproofing layer (NEXCO slab waterproofing grade II), edge protection material) has the performance described in the slab waterproofing in the Structure Construction Management Guidelines (July 2017, East Nippon Expressway Company Limited, Central Nippon Expressway Company Limited, West Nippon Expressway Company Limited).

[0137] <Cured film> The cured film of one embodiment includes a cured product of the resin composition (a cured product obtained by curing the resin composition). The cured film can also be called a coating film.

[0138] The cured film of this embodiment can be obtained, for example, by applying the resin composition to a substrate or the like and curing the resulting coating film for 7 days or more under standard conditions of 23°C and 50% RH. The conditions for preparing the cured film when measuring the physical properties of the cured film may be, for example, the preparation conditions described in the Examples.

[0139] The thickness of the cured film of this embodiment may be 0.1 mm or more, 0.2 mm or more, or 0.3 mm or more, and may be 5.0 mm or less, 3.0 mm or less, or 2.0 mm or less. When the thickness of the cured film is in this range, the peeling prevention effect tends to be more sufficient.

[0140] The cured film of this embodiment may be slightly colored or slightly cloudy, but preferably has excellent transparency. The haze of the cured film of this embodiment, measured at a film thickness of 0.3 mm, may be 70% or less, 50% or less, 30% or less, or 20% or less. The haze value of the cured film can be adjusted with additives or the like to improve appearance, such as glare. Haze can be measured in accordance with JIS K 7136:2000, "Determination of haze for plastics - transparent materials."

[0141] The cured film of this embodiment may have a total light transmittance of 10% or more, 30% or more, 50% or more, 60% or more, or 80% or more when measured at a film thickness of 0.3 mm. When the total light transmittance of the cured film is within this range, abnormalities such as cracks under the cured film tend to be easily visible even after the cured film is formed. The total light transmittance can be measured in accordance with JIS K 7375:2008 "Plastics - Determination of total light transmittance and total light reflectance."

[0142] The cured film of this embodiment may have a grip elongation of 150% or more, 200% or more, or 250% or more at 23°C when measured at a film thickness of 0.3 mm. When the grip elongation of the cured film is within this range, the film tends to have better out-of-plane bending resistance. In this specification, the grip elongation can be measured in accordance with JIS A 6021:2011.

[0143] The cured film of this embodiment may have a gauge length elongation of 150% or more, 200% or more, or 250% or more at 23°C when measured at a film thickness of 0.3 mm. When the gauge length elongation of the cured film at 23°C is within this range, the film tends to have better out-of-plane bending resistance. The grip elongation can be measured in accordance with JIS A 6021:2011.

[0144] The cured film of this embodiment may have a breaking stress of 15 MPa or more, 25 MPa or more, 30 MPa or more, or 40 MPa or more at 23°C when measured at a film thickness of 0.3 mm. When the breaking stress of the cured film is within this range, the film tends to have better out-of-plane bending resistance. The breaking stress can be measured in accordance with JIS A 6021:2011.

[0145] The cured film of this embodiment may have a tensile modulus of elasticity of 1 to 500 MPa, preferably 10 to 300 MPa, and more preferably 50 to 250 MPa, measured at 23°C with a film thickness of 0.3 mm. The tensile modulus of elasticity can be measured in accordance with JIS A 6021:2011.

[0146] In the cured film of this embodiment, the loss tangent (tan δ) measured by dynamic viscoelasticity measurement does not need to have a maximum value in the temperature range of -10 to 30°C. When the loss tangent does not have a maximum value in such a temperature range, the changes in the breaking stress and gauge length elongation within the above temperature range (the temperature range where the loss tangent does not have a maximum value) are small, resulting in excellent toughness and reliable load-bearing capacity even in environments such as cold and hot climates. Dynamic viscoelasticity measurement can be performed by the method described in the Examples. The maximum value of the loss tangent can be determined from a graph showing the temperature dependence of the ratio of the loss modulus (E") to the storage modulus (E') measured by dynamic viscoelasticity measurement (the value obtained by dividing the loss modulus by the storage modulus: E" / E').

[0147] The cured film of this embodiment may have a breaking stress retention of 60% or more, 80% or more, or 90% or more before and after an accelerated exposure test. The cured film may have a gauge length elongation retention of 60% or more, 80% or more, or 90% or more before and after an accelerated exposure test. The accelerated exposure test is a weather resistance test conducted using a sunshine weatherometer specified in JIS B 7753:2007 for a test time of 2500 hours.

[0148] The color difference (ΔE) of the cured film after an accelerated exposure test may be 15 or less, 5 or less, or 3 or less. The color difference can be determined in accordance with JIS K5600-4-6:1999 "Colorimetry (SCE) of General Test Methods for Paints" by measuring test pieces before and after the accelerated exposure test.

[0149] The gloss retention of the cured film before and after the accelerated exposure test may be 60% or more, or 80% or more. The gloss retention can be determined by measuring the test piece before and after the accelerated exposure test in accordance with JIS K5600-4-7:1999 "Specular gloss (60°) in general test methods for paints."

[0150] Regarding the flexibility (crack-following ability) of the cured film, the elongation of the cured film may be 3 mm or more, 10 mm or more, or 20 mm or more. Note that the concrete surface protection performance is required in accordance with the performance verification for concrete surface protection in the Structure Construction Management Guidelines (July 2017, East Nippon Expressway Company Limited, Central Nippon Expressway Company Limited, West Nippon Expressway Company Limited).

[0151] <Coating methods for civil engineering and architectural structures> A coating method for a civil engineering or architectural structure according to one embodiment includes a step of applying the resin composition to the civil engineering or architectural structure. The coating method of this embodiment may include, for example, a step of applying the resin composition to the target civil engineering or architectural structure to form a coating film (resin layer) and a step of curing the coating film to form a cured film (cured product layer). The coating method of this embodiment may also include, for example, a step of applying at least one selected from the group consisting of a primer, a leveling agent, a gas barrier paint, a reinforcing paint, and a putty to the surface of the civil engineering or architectural structure before applying the resin composition to the civil engineering or architectural structure. The coating method of this embodiment may also include a step of applying a reinforcing mesh or staple fiber (e.g., a step of impregnating the mesh or staple fiber with the resin composition). The term "civil engineering or architectural structure" refers to, for example, civil engineering structures such as bridges, elevated roads, dams, tunnels, roads, and land developments; buildings, condominiums, and houses.

[0152] Examples of methods for applying the resin composition to civil engineering and architectural structures (e.g., methods for forming a coating film) include painting, coating, etc. Since the resin composition has a sufficiently long usable life, it can also be applied manually using a spray, trowel, spatula, brush, roller, etc. By applying the resin composition manually, a coating film of a desired thickness can be formed outdoors.

[0153] The unevenness control agent and putty are preferably used when the surface of a civil engineering or architectural structure is uneven. By applying the unevenness control agent and putty to the surface of the civil engineering or architectural structure, it becomes easier to apply the resin composition. The unevenness control agent may be applied after applying a primer to the surface of the concrete structure.

[0154] In the coating method of this embodiment, the thickness of the coating film can be adjusted depending on the thickness after curing (thickness of the cured film (cured product layer)), and may be, for example, 0.1 mm or more, 0.2 mm or more, or 0.3 mm or more, and 5.0 mm or less, 3.0 mm or less, or 2.0 mm or less. When the coating film thickness is within this range, the peeling prevention effect tends to be better. In the coating method of this embodiment, the resin composition may be applied in multiple steps.

[0155] In the coating method of this embodiment, a resin layer made of a primer may be provided as a first layer to enhance adhesion between the cured film (cured product layer) and the surface of the civil engineering or architectural structure. The resin constituting the first resin layer may be, for example, an acrylic resin, a urethane resin, an epoxy resin, or a vinyl acetate resin. From the standpoints of odor and environmental impact, the primer is preferably a solvent-free or aqueous material. The primer is also preferably a one-component material. The thickness of the first layer can be adjusted depending on the thickness of the cured film (cured product layer). For example, it may be 0.01 mm or more, 0.05 mm or more, or 0.1 mm or more, and may be 1.0 mm or less, 0.5 mm or less, or 0.3 mm or less. A thickness of the first layer within this range tends to provide excellent adhesion and suppress the occurrence of blistering. The primer may be applied in multiple steps to form the first layer.

[0156] In the coating method of this embodiment, after forming the cured film (cured product layer), a resin layer made of a topcoat material may be provided as a third layer. By providing a resin layer made of a topcoat material, the strength of the cured film (cured product layer) can be further increased. The resin constituting the resin layer serving as the third layer may be, for example, a urethane resin, a fluororesin, or an acrylic silicone resin. From the viewpoints of odor and environmental impact, the topcoat material is preferably a solventless material or an aqueous material. Furthermore, the topcoat material is preferably a one-component material. The thickness of the third layer can be adjusted according to the thickness of the cured film (cured product layer). For example, it may be 0.01 mm or more, 0.05 mm or more, or 0.1 mm or more, and may be 1.0 mm or less, 0.5 mm or less, or 0.3 mm or less. When the thickness of the third layer is within this range, excellent weather resistance and aesthetic appearance tend to be maintained for a long period of time. In forming the third layer, the topcoat material may be applied in multiple coats.

[0157] <How to prevent tiles from falling off> In one embodiment, a method for preventing tile peeling includes fixing an existing tiled exterior wall surface with metal anchors and covering the exterior wall surface with a coating layer, the coating layer including a layer containing a cured product of the resin composition.

[0158] An existing tiled exterior wall refers to an exterior wall that has a laminated structure in which inorganic tiles with low water absorption and excellent durability are attached to a concrete frame with cement mortar or the like, forming joints. Examples of tiles include porcelain tiles and stoneware tiles. The tiles are preferably porcelain tiles.

[0159] There are no particular restrictions on the method of fixing the exterior wall surface with metal anchors, and existing construction methods can be applied. It is preferable to drill a hole in the center of the tile and drive the anchor in so that the tile can be fixed to the building frame, but it can also be driven into the joints. It is also preferable to insert the anchor so that its tip reaches the building frame by 20 mm or more. The number of anchors to be driven in is determined based on the mass of the existing tiled exterior wall. 2 ) is preferably driven in. It is preferable to use an anchor with an injection port, and after driving it in, to inject a reactive curing resin such as epoxy resin and reinforce the inside of the frame with resin. It is preferable that the anchor can withstand the force of being pulled out of the frame by expanding its tip after driving in. One suitable example of an anchor is an anchor that has a slit formed in the hollow shaft of the anchor from the middle in the axial direction to the tip and has a built-in extender, and that has a structure in which the tip can be expanded and driven into the frame by further driving the extender with a metal rod or the like after driving in the anchor.

[0160] The method for covering the exterior wall surface with a coating layer can be the method described in the above-mentioned coating method (applying method) for civil engineering and architectural structures.

[0161] <Structure> In one embodiment, the structure comprises an exterior wall structure including tiles and a coating layer disposed on the exterior wall structure.

[0162] One embodiment of the coating layer includes a layer containing a cured product of the resin composition. Another embodiment of the coating layer includes a first layer and a second layer in this order from the outer wall structure. Here, the first layer is a resin layer of any of acrylic resin, acrylic styrene resin, urethane resin, epoxy resin, and vinyl acetate resin. The second layer is a layer containing a cured product of the resin composition. In this embodiment, the coating layer may further include a third layer, which is a resin layer of any of urethane resin, fluororesin, and acrylic silicone resin, on the second layer opposite to the first layer. Another embodiment of the coating layer includes a second layer and a third layer in this order from the outer wall structure.

[0163] The resin constituting the resin layer as the first layer can be exemplified by the same resin as that constituting the resin layer as the first layer in the coating method (applying method) for civil engineering and architectural structures. The resin constituting the resin layer as the third layer can be exemplified by the same resin as that constituting the resin layer as the third layer in the coating method (applying method) for civil engineering and architectural structures.

[0164] The structure of this embodiment may further include metal anchors that hold the tiles and / or coating layers included in the exterior wall structure. [Example]

[0165] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0166] <Evaluation method> (Characteristics of resin composition) [Measurement of non-volatile content] The resin composition was mixed until it became homogeneous and then measured according to JIS K5601-1-2: 2008. In this measurement, the heating temperature was 140°C and the heating time was 180 minutes.

[0167] [Acid value measurement] The resin composition was mixed until homogeneous and then measured for acid value (titration method) according to JIS K5601:1999 using an automatic titrator COM-1600 manufactured by Hiranuma Co., Ltd. In this measurement, 3.0 g of the resin composition was thoroughly dispersed in 10 mL of pure water, and then 50 mL of ethanol was added to prepare a titration solution.

[0168] [Viscosity measurement] The resin composition was mixed until homogeneous, and the viscosity was measured according to JIS-Z8803:2011 (Method for measuring viscosity of liquids) using a TVE25H E-type viscometer manufactured by Toki Sangyo Co., Ltd. A 3° × R9.7 cone rotor was used, and the sample volume was 0.2 mL. The measurement temperature was 23°C. The viscosity was measured at rotation speeds of 5 rpm and 50 rpm, and the thixotropy index (TI) was calculated by dividing the viscosity at 5 rpm by the viscosity at 50 rpm.

[0169] [Measurement of sagging resistance] Based on the method described in ASTM D4400, a glass plate (thickness: 4 mm × width: 200 mm × height: 200 mm) was placed on a horizontal table at 23°C. The resin composition was spread into the groove of a metal sag tester (ASTM ASM-3, manufactured by BYK) and then slid against the glass to coat the resin composition in parallel bands of different thicknesses. The glass plate was then immediately held vertically with the thicker band facing downwards so that the trajectory of the sag tester was horizontal for 8 hours, and the flow state of the resin composition was examined. The presence or absence of paint flowing into the width of the trajectory was confirmed, and the largest band where the resin composition did not flow was determined. The coating thickness of the resin composition in this largest band was evaluated according to the following criteria. A large coating thickness of the resin composition means that there is little (or no) sagging even when the resin composition is applied thickly. A: The coating thickness of the resin composition was 1.5 mm or more. B: The coating thickness of the resin composition was 1.0 mm or more and less than 1.5 mm. C: The coating thickness of the resin composition was 0.75 mm or more and less than 1.0 mm. D: The coating thickness of the resin composition was less than 0.75 mm.

[0170] (Characteristics of the cured film) [Cured film preparation] The resin composition was mixed until it was uniform, and then applied to the release-treated substrate in a 0.3 kg / m² application. 2 After drying at room temperature (23°C) to confirm that there was no tack, the same amount was applied again. After applying three times in total, the coating was cured for seven days under standard conditions of 23°C and 50% RH to produce a cured film as an evaluation sample. The thickness of the cured film was 0.3 mm.

[0171] [Preparation of multilayer cured film] The resin composition was mixed until it was uniform, and then applied to the release-treated substrate in a 0.3 kg / m² application. 2 After drying at room temperature (23°C) to confirm that there was no tack, the same amount was applied again. After applying a total of three times, the surface was dried at room temperature (23°C) to confirm that there was no tack, and then topcoat 1 (water-based fluororesin 1) or topcoat 2 (water-based fluororesin 2) was applied at 0.1 kg / m per application. 2 After drying at room temperature (23°C) to confirm that there was no tack, the same amount was applied again. This was left to cure for 7 days under standard conditions of 23°C and 50% RH to produce a cured film that served as an evaluation sample.

[0172] [Tensile test (grip elongation, gauge elongation, breaking stress, and tensile modulus)] Test pieces were punched out from the cured film obtained above using a No. 3 dumbbell, and the grip elongation, gauge elongation, breaking stress, and tensile modulus of the obtained test pieces were measured in accordance with JIS A 6021:2011.

[0173] [Water resistance (water whitening resistance, water swelling rate, and elution rate)] The cured film obtained above was cut into a size of 25 x 25 mm, and the initial mass W0 (mg) was measured. After immersion in hot water at 60°C for 24 hours, the moisture on both sides of the cured film was wiped off with a Kimtowel. The water whitening resistance (appearance) of the cured film was evaluated, and the wet mass Wt (mg) of the cured film was measured. The wet mass Wt (mg) was then measured. The cured film was then force-dried at 100°C for 3 hours, and the dry mass Wd (mg) was measured. Note that all masses were measured to one decimal place.

[0174] The appearance was observed, and the water whitening resistance was evaluated according to the following criteria. A: There was no change in appearance. B: Whitened, but when the cured film was placed on a Kimtowel, the pattern was visible. C: Significant whitening occurred, and the pattern underneath the cured film was not visible.

[0175] The water swelling ratio was calculated using the following formula (C). Water swelling rate (mass%) = (Wt-W0) / W0 (formula (C))

[0176] The dissolution rate was calculated using the following formula (D). Elution rate (mass%)=(W0-Wd) / W0 (formula (D))

[0177] [Haze measurement] The haze of the cured film obtained above was measured using NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K 7136:2000 (Method of determining haze of plastics-transparent materials).

[0178] [Measurement of total light transmittance] The total light transmittance of the cured film obtained above was measured using NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K 7136:2000 (Plastics - Determination of total light transmittance and total light reflectance).

[0179] [Weather resistance (elongation retention rate and stress retention rate)] Test pieces measuring 150mm long x 70mm wide x 0.3mm thick were taken from the cured film obtained above and subjected to an accelerated exposure test using Method 1, Cycle A of the xenon lamp method specified in JIS K 5600-7-7:2008. They were then aged for 3 days under standard conditions of 25°C and 50% RH, and then subjected to tensile tests (gauge length elongation and breaking stress) and compared with the tensile properties before the accelerated exposure test.

[0180] (Structure characteristics) [Crack followability] Crack follow-up was evaluated according to the method specified in JSCE-K 532-2013. Test specimens were prepared according to the following procedure. The base is prepared using the method specified in 4.3 of the said regulation, and 0.1 kg / m 2 A one-component water-based primer (primer 1 (acrylic styrene resin)) was applied in an amount of 0.3 kg / m per coat and dried at room temperature for 3 hours to obtain a resin layer (first layer). 2 The resin composition was applied so that the thickness of the cured resin composition was 1 / 4 of the cured resin composition. After drying at room temperature (23°C) and confirming that there was no tack, the same amount was applied again. After applying the resin composition three times in total, the sample was cured for seven days under standard conditions of 23°C and 50% RH to obtain a layer (second layer) containing a cured product of the resin composition, which served as an evaluation sample. Each evaluation sample was evaluated three times and judged as follows: A: In all three tests, the cured film did not break at a displacement of 20 mm. B: In two out of three cases, there was no breakage of the cured film at a displacement of 20 mm. C: In one of three tests, the cured film did not break at a displacement of 20 mm. D: In all three tests, the cured film broke at a displacement of less than 20 mm.

[0181] [Weather resistance (elongation retention rate and stress retention rate)] Test pieces measuring 150 mm long x 70 mm wide x 0.3 mm thick were taken from the cured film obtained in the above [Preparation of multilayer cured film] and subjected to an accelerated exposure test using Method 1, Cycle A of the xenon lamp method specified in JIS K 5600-7-7:2008. The test pieces were then aged for 3 days under standard conditions of 25°C and 50% RH, and tensile tests (gauge length elongation and breaking stress) were performed, and the tensile properties were compared with those before the accelerated exposure test.

[0182] [Repeated hot and cold performance] The test was carried out in accordance with the Urban Renaissance Agency's "Common Specifications for Maintenance Works: Collection of Registrations for Quality Assessment Standards for Equipment and Construction Methods, 2017 Edition." Specifically, a 45-piece glazed ceramic tile was applied to a mortar board (300mm wide x 300mm long x 50mm thick) and an unapplied mortar board, with a one-component water-based primer (primer 1 (acrylic styrene resin)) applied at 0.1 kg / m. 2 The resin layer (first layer) was obtained by applying a coating amount of 0.3 kg / m per coating and drying at room temperature for 3 hours. 2 Each resin composition was applied so that the thickness was 0.08 kg / m, and after drying at room temperature (23°C) to confirm that there was no tack, the same amount was applied again. Each resin composition was applied three times in total to obtain a layer containing the resin composition. Then, a one-component water-based topcoat (Topcoat 1 (Water-based Fluorine Resin 1)) was applied at 0.08 kg / m 2 The coating was applied in an amount of 1000 ppm, dried at room temperature, and confirmed to be tack-free. The same amount was then applied again to obtain a resin layer (third layer). The resin composition was then cured under standard conditions of 23°C and 50% RH for 7 days, forming a layer (second layer) containing the cured resin composition, thereby obtaining a sample for evaluation. After 3 days of curing, the sides were sealed with epoxy resin (E250, manufactured by Konishi Co., Ltd.).

[0183] The evaluation samples prepared as described above were immersed in water at room temperature (23°C) for 16 hours and then dried in a dryer at 80°C for 8 hours. This cycle was repeated 10 times, and then the samples were attached to a 40mm x 40mm metal attachment with epoxy resin (Konishi Co., Ltd., E250), and incisions were made around the sample that reached the substrate. The tensile adhesive strength was measured using a hydraulic tensile tester. Tests were performed at three locations in the center of the specimen and three locations at the end of the specimen (approximately 10mm from the edge), and the average value was calculated.

[0184] [Out-of-plane bending performance] The test was carried out in accordance with the Urban Renaissance Agency's "Common Specifications for Maintenance Works: Collection of Registrations for Quality Assessment Standards for Equipment and Construction Methods, 2017 Edition." Specifically, a mortar board (100mm wide x 600mm long x 30mm thick) was split into two at the center of the longitudinal direction, and the broken surfaces were butted together. A one-component water-based primer (primer 1 (acrylic styrene resin)) was applied at 0.1 kg / m² to the top surface of the formwork. 2 The resin layer (first layer) was obtained by applying a coating amount of 0.3 kg / m per coating and drying at room temperature for 3 hours. 2 Each resin composition was applied so that the thickness of the resin composition was 0.08 kg / m. After drying at room temperature and confirming that there was no tack, the same amount was applied again. Each resin composition was applied three times in total to obtain a layer containing the resin composition. Then, a one-component water-based topcoat (Topcoat 1 (Water-based Fluorine Resin 1)) was applied at 0.08 kg / m. 2 The coating was applied in a coating amount of 1000 ppm, dried at room temperature, and after confirming that there was no tack, the same amount was applied again to obtain a resin layer (third layer). The resin composition was then cured by aging for 7 days under standard conditions of 23°C and 50% RH, forming a layer (second layer) containing the cured resin composition, thereby obtaining an evaluation sample. A four-point bending test was then performed by loading the bottom of the evaluation sample at a rate of 5 mm / min. The sample was displaced up to 40 mm, and the presence or absence of fracture in the cured film was confirmed.

[0185] <Synthesis of aqueous polyurethane resin dispersion> (Synthesis Example 1) In a reactor equipped with a stirrer and heater, 2000 g (1.00 mol) of ETERNACOLL UH-200 (registered trademark; polycarbonate diol manufactured by Ube Industries, Ltd.; number average molecular weight 2000; hydroxyl value 56.1 mg KOH / g; polycarbonate diol obtained by reacting 1,6-hexanediol with a carbonate ester), 553.8 g (2.49 mol) of isophorone diisocyanate, and 104.6 g (0.780 mol) of 2,2-dimethylolpropionic acid were heated in 936 g of dipropylene glycol dimethyl ether in the presence of a catalyst under a nitrogen atmosphere at 80 to 90°C for 5 hours. The isocyanate group content at the end of the urethanization reaction was 1.71% by mass. The reaction mixture was then heated to 80°C, and 74.1 g of triethylamine was added, followed by stirring for 30 minutes. The reaction mixture was withdrawn and added to 5367 g of water with strong stirring, and then 74.5 g of 2-methyl-1,5-pentanediamine was added as a chain extender to obtain an aqueous polyurethane resin dispersion (PUD) P1.

[0186] (Synthesis Examples 2 to 4) Aqueous polyurethane resin dispersions (PUD) P2 to P4 were synthesized in the same manner as in Synthesis Example 1, except that the raw materials and the charging ratios (mass ratios) shown in Table 1 were changed. In particular, the charging ratios of the acidic group-containing polyol and the amount of water were adjusted so that the acid value and nonvolatile content concentration were the calculated values shown in Table 1. P4 was synthesized by synthesizing an aqueous polyurethane resin dispersion using the method described in JP 2019-035240 A, and then distilling off methyl ethyl ketone under reduced pressure.

[0187] [Table 1]

[0188] The materials used in Table 1 are as follows: UH-200: Polycarbonate diol (manufactured by Ube Industries, Ltd., product name: ETERNACOLL UH-200, hydroxyl value: 56.1 mg KOH / g) UH-100: Polycarbonate diol (manufactured by Ube Industries, Ltd., product name: ETERNACOLL UH-100, hydroxyl value: 112.2 mg KOH / g) C-2090: Polycarbonate diol (manufactured by Kuraray Co., Ltd., product name: Kuraray Polyol C-2090, hydroxyl value: 56.1 mg KOH / g) BDL: 1,4-butanediol IPDI: Isophorone diisocyanate HMDI: Dicyclohexylmethane-4,4'-diisocyanate DMPA: 2,2-dimethylolpropionic acid DMBA: 2,2-bis(hydroxymethyl)butyric acid MPMD: 2-methyl-1,5-pentanediamine IPDA: Isophoronediamine TEA: Triethylamine DMM: Dipropylene glycol dimethyl ether NEP: N-ethylpyrrolidone MEK: Methyl ethyl ketone

[0189] (Examples 1, 2A, and 2B and Comparative Examples 1A, 1B, 2A, 2B, and 3) The components listed in the "Composition" column of Table 2, in the amounts (g) listed, were mixed until uniform, to obtain the resin compositions of Examples 1, 2A, and 2B and Comparative Examples 1A, 1B, 2A, 2B, and 3. These resin compositions were used to evaluate the physical properties of the resin compositions, the cured films, and the structures, using the methods described above. The results are shown in Tables 2 and 3.

[0190] (Examples 3 and 4) Using the resin composition obtained in Example 1 and the topcoat material 1 listed in Table 4, a layer containing a cured product of the resin composition was obtained by the method described above in [Weather resistance (elongation retention and stress retention)]. Using the resin composition obtained in Example 1 and the topcoat material 2 listed in Table 4, a layer containing a cured product of the resin composition was obtained by the method described above in [Weather resistance (elongation retention and stress retention)]. Using these structures, the above [Weather resistance (elongation retention and stress retention)] was evaluated. The results are shown in Table 4.

[0191] (Examples 5 and 6) Using the resin composition obtained in Example 1 and the primer 1 listed in Table 4, a layer containing a cured product of the resin composition was obtained by the methods described above in [Hot / Cool Cycling Performance] and [Out-of-Plane Bending Performance]. The structure of Example 5 was obtained using the resin composition obtained in Example 1, the topcoat 1 listed in Table 3, and the primer 1 listed in Table 3, a layer containing a cured product of the resin composition was obtained by the methods described above in [Hot / Cool Cycling Performance] and [Out-of-Plane Bending Performance]. These structures were used to evaluate the [Hot / Cool Cycling Performance] and [Out-of-Plane Bending Performance]. The results are shown in Table 4.

[0192] [Table 2]

[0193] The materials used in Table 2 are as follows: Carbodilite E-05: a compound having a carbodiimide group (manufactured by Nisshinbo Chemical Inc., NCN equivalent 310, emulsion type, active ingredient concentration 40% by mass) Carbodilite V-02: Compound with a carbodiimide group (manufactured by Nisshinbo Chemical Inc., NCN equivalent 590, water-soluble type, active ingredient concentration 40% by mass) Baycoat 20: Polyvalent metal complex (zirconium ammonium carbonate aqueous solution) (manufactured by Nippon Light Metal Co., Ltd., 20% by mass in terms of zirconium oxide) Tinuvin-400DW(N): Water-dispersible UV absorber (BASF Japan Ltd., active ingredient concentration 40% by mass) Tinuvin-123DW(N): Water-dispersible HALS (BASF Japan Ltd., active ingredient concentration 30% by mass) Aerosil R974: Fumed silica (manufactured by Nippon Aerosil Co., Ltd., specific surface area 200 m 2 / g, dimethylsilyl treated) ADEKA NOL UH-756VF: Urethane associative thickener (ADEKA Corporation, active ingredient concentration 32% by mass) Ester compound: 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate BYK-093: Silicone defoamer (BYK-Chemie)

[0194] [Table 3]

[0195] [Table 4]

[0196] The materials used in Table 4 are as follows: Primer 1: Acrylic styrene resin Topcoat 1: Water-based fluororesin 1 (medium gloss, 60° gloss value of multi-layer cured film: 41) Topcoat 2: Water-based fluororesin 2 (low gloss, 60° gloss value of multi-layer cured film 68)

[0197] As shown in Table 2, the coating resin compositions for civil engineering and construction of Examples 1 and 2 had better application properties than the coating resin compositions for civil engineering and construction of Comparative Examples 1 to 3, and the cured products also had good elongation and therefore excellent crack followability, and as shown in Table 3, were also excellent in water resistance and transparency. These results confirmed that the coating resin composition for civil engineering and construction of the present invention has good application properties and is capable of forming cured products with good transparency and water whitening resistance.

Claims

1. A coating resin composition for civil engineering and construction, comprising (a) a polyurethane resin having a polycarbonate structure, (b) an aqueous medium, and (c) a crosslinking agent reactive with an acidic group or a salt thereof, A coating resin composition for civil engineering and construction, which satisfies at least condition A of the following conditions A and B: Condition A: The acid value of the nonvolatile matter in the coating resin composition for civil engineering and construction is 5 to 17 mgKOH / g. Condition B: The acid value of the polyurethane resin (a) having a polycarbonate structure is 5 to 22 mgKOH / g.

2. 2. The coating resin composition for civil engineering and construction use according to claim 1, which satisfies both of the conditions A and B.

3. 3. The coating resin composition for civil engineering and construction use according to claim 1, wherein the polyurethane resin (a) having a polycarbonate structure has an acidic group.

4. 4. The coating resin composition for civil engineering and construction according to claim 1, wherein the polyurethane resin (a) having a polycarbonate structure has a structure derived from a linear aliphatic diol in the polycarbonate structure of the polyurethane resin.

5. 5. The coating resin composition for civil engineering and construction according to claim 1, wherein the polyurethane resin (a) having a polycarbonate structure has a structure derived from an aliphatic polyisocyanate in the polyurethane resin.

6. 6. The coating resin composition for civil engineering and construction use according to claim 1, wherein the crosslinking agent (c) reactive with an acidic group or a salt thereof comprises a compound having a carbodiimide group.

7. Further comprising a thixotropic agent (e), 7. The coating resin composition for civil engineering and construction according to claim 1, wherein the content of the thixotropy-imparting agent (e) is 20 mass% or less, based on the total amount of non-volatile components of the coating resin composition for civil engineering and construction.

8. 8. The coating resin composition for civil engineering and construction according to any one of claims 1 to 7, wherein the viscosity of the coating resin composition for civil engineering and construction is measured in accordance with JIS-Z8803:2011 (Method for measuring viscosity of liquids) using an E-type viscometer with a 3° x R9.7 cone rotor at a rotation speed of 5 rpm and at 23°C, and is 6.0 to 60 Pa s.

9. The coating resin composition for civil engineering and construction according to any one of claims 1 to 8, wherein, when the coating resin composition for civil engineering and construction is applied and a sagging test is carried out based on ASTM D4400, the coating thickness of the coating resin composition for civil engineering and construction without running is 0.75 mm or more.

10. 10. The coating resin composition for civil engineering and construction according to claim 1, wherein when a coating film formed from the coating resin composition for civil engineering and construction is cured for 7 days under standard conditions of 23°C and 50% RH to form a cured film, the grip elongation at 23°C measured on a cured film having a film thickness of 0.3 mm according to JIS A 6021:2011 is 150% or more.

11. 11. The coating resin composition for civil engineering and construction according to claim 1, wherein a coating film formed from the coating resin composition for civil engineering and construction is cured for 7 days under standard conditions of 23°C and 50% RH to form a cured film, and the cured film has a total light transmittance of 10% or more as measured with a cured film having a film thickness of 0.3 mm.

12. The coating resin composition for civil engineering and construction according to any one of claims 1 to 11, which is used for preventing tile peeling, waterproofing of buildings, preventing concrete structure peeling, protecting concrete structures, or waterproofing of concrete floor slabs.

13. A cured film comprising a cured product of the coating resin composition for civil engineering and construction use according to any one of claims 1 to 11.

14. A method for coating a civil engineering or architectural structure, comprising a step of applying the coating resin composition for civil engineering or architectural structure according to any one of claims 1 to 11 to the civil engineering or architectural structure.

15. The method includes a step of fixing an existing tiled exterior wall surface with metal anchors and covering the exterior wall surface with a coating layer, A method for preventing tile peeling, wherein the coating layer comprises a layer containing a cured product of the coating resin composition for civil engineering and construction use according to any one of claims 1 to 11.

16. A method for coating a civil engineering and architectural structure, comprising a step of applying to the civil engineering and architectural structure a coating resin composition for civil engineering and architectural use, the coating resin composition comprising (a) a polyurethane resin having a polycarbonate structure, (b) an aqueous medium, and (c) a crosslinking agent reactive with an acidic group or a salt thereof, and satisfying at least one of the following conditions A and B: Condition A: The acid value of the nonvolatile matter in the coating resin composition for civil engineering and construction is 5 to 17 mgKOH / g. Condition B: The acid value of the polyurethane resin (a) having a polycarbonate structure is 5 to 22 mgKOH / g.

17. A method for improving the appearance of a tiled exterior wall surface by fixing the surface with metal anchors and covering the surface with a coating layer, The method for preventing tile peeling, wherein the coating layer contains a layer containing a cured product of a coating resin composition for civil engineering and construction, which comprises (a) a polyurethane resin having a polycarbonate structure, (b) an aqueous medium, and (c) a crosslinking agent reactive with an acidic group or a salt thereof, and satisfies at least one of the following conditions A and B: Condition A: The acid value of the nonvolatile matter in the coating resin composition for civil engineering and construction is 5 to 17 mgKOH / g. Condition B: The acid value of the polyurethane resin (a) having a polycarbonate structure is 5 to 22 mgKOH / g.

18. An exterior wall structure including tiles, and a coating layer provided on the exterior wall structure, A structure, wherein the coating layer comprises a layer containing a cured product of the coating resin composition for civil engineering and construction use according to any one of claims 1 to 11.

19. A structure comprising an exterior wall structure including tiles and a coating layer provided on the exterior wall structure, the coating layer includes a first layer and a second layer in this order from the outer wall structure, the first layer is a resin layer selected from the group consisting of an acrylic resin, an acrylic-styrene resin, a urethane resin, an epoxy resin, and a vinyl acetate resin; A structure, wherein the second layer is a layer comprising a cured product of the coating resin composition for civil engineering and construction use according to any one of claims 1 to 11.

20. 20. The structure according to claim 19, wherein the coating layer further comprises a third layer of a resin layer selected from a urethane resin, a fluororesin, and an acrylic silicone resin, on the second layer and on the opposite side to the first layer.

21. 21. The structure of claim 19 or 20, further comprising metal anchors that hold the tiles and / or the coating layer included in the exterior wall structure.

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