Two-component curing composition for coating the inner walls of water pipes, its cured product, and water pipes with inner wall coating.

Abstract

This disclosure provides a two-component curing composition for coating the inner walls of water pipes that exhibits excellent curability in low-temperature ranges, suppresses or prevents foaming during curing, and forms a coating with excellent chemical resistance and hot water resistance. [Solution] This disclosure relates to a two-component curable composition for coating the inner wall of a water pipe, which hardens upon contact between a main component (A) and a curing agent (B), wherein the main component (A) contains an isocyanate compound (a1), and the curing agent (B) contains a primary or secondary amine compound component (b1) and an alcohol component (b2) containing a polyhydric alcohol compound (b2-1) having a cyclic hydrocarbon group and a hydroxyl value of 10 mg KOH / g or more and 1,500 mg KOH / g or less, and has a viscosity of 100 mPa·s or more and 500,000 mPa·s or less at 25°C. This is a two-component curing type composition for coating the inner walls of water pipes.

Description

[Technical Field]

[0001] This disclosure relates to a two-component curing composition for coating the inner walls of water pipes, a cured product thereof, and water pipes with the inner wall coating already applied. [Background technology]

[0002] Over time, water pipes, such as water distribution and drainage pipes, deteriorate, which can lead to leaks from inside the pipes or the occurrence of rusty water, potentially resulting in the complete loss of their function. For example, repair work on water pipes running through the common areas of apartment buildings or in factories may require the suspension of water and sewage supply. In the case of underground water pipes, work such as discovering leaks or deteriorated areas, repairing the pipes by excavation, replacing them with new pipes, and backfilling the excavated areas may be necessary. Therefore, repairing deteriorated sections of water pipes themselves or their joints, or replacing them with new pipes, requires considerable effort, expense, and time. Furthermore, these repairs are carried out under various environmental conditions. Consequently, there is a need for simple repair methods for water pipes or technologies to suppress the deterioration of water pipes over time, across a wide temperature range.

[0003] For example, the technology described in Patent Document 1 is a technique for preventing leakage inside buried pipes. Patent Document 1 describes that by using a urethane resin composition for lining pipes that includes (A) a polyester polyether polyol, (B) an ester compound of an oxy fatty acid oligomer of dimers or more formed by the condensation of fatty acids having hydroxyl groups together or fatty acids having hydroxyl groups and fatty acids not having hydroxyl groups, and an alcohol, the lining material can be easily released from the pipe in the event of deformation of the pipe due to underground movements such as road vibrations or earthquakes, thereby exhibiting an effect of suppressing leakage when the pipe cracks or breaks. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2009-091374 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, since the lining material described in Patent Document 1 is easily released from the mold, a problem arises in that the released lining material itself becomes a new deposit inside the water pipe. Furthermore, Patent Document 1 does not consider at all the construction conditions for coating the inside of the water pipe with the lining material formed from the urethane resin composition for lining, particularly the external atmosphere during construction. Specifically, when repair work on water pipes is carried out in cold regions or low-temperature environments (for example, in the range of -9°C to -10°C to 0°C), the curing reaction of the composition becomes difficult to proceed, and conventional urethane resin compositions for lining, such as those described in Patent Document 1, tend to harden poorly. On the other hand, when carried out in high-temperature or high-humidity environments, the coating film tends to foam, and a decrease in the chemical resistance of the resulting coating film or deterioration of the coating film has been observed. Furthermore, because water pipes are subjected to solutions containing various chemical substances or hot water, the membrane covering the inner wall of the water pipes tends to deteriorate easily.

[0006] Therefore, the present disclosure aims to provide a two-component curing composition for coating the inner walls of water pipes that exhibits excellent curability in the low-temperature range (e.g., -9°C to -10°C) to the warm range (e.g., around 45°C), suppresses or prevents foaming during curing, and forms a coating that combines excellent elongation, high chemical resistance, and high heat resistance while maintaining a predetermined hardness. [Means for solving the problem]

[0007] In view of the above problems, the inventors have diligently conducted research and have confirmed that a two-component curing composition using a main component (A) having a predetermined composition and a curing agent (B) having a predetermined composition exhibits excellent curability in the range from low temperatures (e.g., -9°C to -10°C) to warm temperatures (e.g., around 45°C), suppresses or prevents foaming during curing, and forms a coating that maintains a predetermined hardness while possessing excellent elongation, high chemical resistance, and high heat resistance. Therefore, based on the above findings, we have completed the present invention. That is, this disclosure is as follows.

[0008] [1] A two-component curing type composition for coating the inner wall of a water pipe, which hardens upon contact between a main component (A) and a hardening agent (B) to coat the inner wall of the water pipe, The main component (A) contains an isocyanate compound (a1), The curing agent (B) contains a primary or secondary amine compound component (b1) and an alcohol component (b2) containing a polyhydric alcohol compound (b2-1) having a cyclic hydrocarbon group and a hydroxyl value of 10 mg KOH / g or more and 1,500 mg KOH / g or less, and has a viscosity of 100 mPa·s or more and 500,000 mPa·s or less at 25°C, and is a two-component curing composition for coating the inner walls of water pipes.

[0009] [2] The first or second class amine compound component (b1) contains one or more selected from the group consisting of a first amine compound (b1-1) and a second amine compound (b1-2), the two-component curable composition for coating the inner wall of a water pipe as described in [1].

[0010] [3] The curing agent (B) further contains a dicarboxylic acid ester compound as a plasticizer, a two-component curing composition for coating the inner wall of a water pipe according to [1] or [2].

[0011] [4] A two-component curable composition for coating the inner wall of a water pipe according to any one of [1] to [3], wherein the weight-average molecular weight (Mw) of the polyhydric alcohol compound (b2-1) is 100 to 2,000.

[0012] [5] A two-component curing composition for coating the inner wall of a water pipe, wherein the main component (A) and the curing agent (B) come into contact and harden to form a film that covers the inner wall of the water pipe, thereby coating the inner wall of the water pipe, as described in any of [1] to [4].

[0013] [6] The alcohol component (b2) comprises the polyhydric alcohol compound (b2-1) and the aromatic ring-containing polyhydric alcohol compound (b2-2.1) having an aromatic ring, as described in any of [1] to [5].

[0014] [7] The two-component curable composition for coating the inner wall of a water pipe according to [2], wherein the amine value of each compound constituting the primary or secondary amine compound component (b1) is in the range of 20 mg KOH / g or more and 800 mg KOH / g or less.

[0015] [8] The polyhydric alcohol compound (b2-1) is a vegetable oil-modified polyol, a two-component curable composition for coating the inner wall of a water pipe according to any one of [1] to [7].

[0016] [9] The water pipe is a drain pipe, a two-component curing composition for coating the inner wall of a water pipe according to any one of [1] to [8].

[0017] A cured product obtained by curing a two-component curing type composition for coating the inner wall of a water pipe, as described in any of

[10] [1] to [9].

[0018]

[11] A water pipe with an inner wall coating, comprising a water pipe body and the hardened material described in

[10] covering the inner wall of the water pipe body. [Effects of the Invention]

[0019] According to this disclosure, a coating is formed that exhibits excellent curability in the low temperature range (e.g., -9°C to -10°C) to the warm temperature range (e.g., around 45°C), suppresses or prevents foaming during curing, maintains a predetermined hardness, and combines excellent elongation, high chemical resistance, and high heat resistance. According to this disclosure, it is possible to provide a cured product that exhibits excellent curability in the low temperature range (e.g., -9°C to -10°C) to the warm temperature range (e.g., around 45°C), suppresses or prevents foaming during curing, maintains a predetermined hardness, and possesses excellent elongation, high chemical resistance, and high heat resistance, as well as a water pipe with an inner wall coating having said cured product. [Brief explanation of the drawing]

[0020] [Figure 1] Figure 1 shows the IR absorption spectra of the polyols used in the examples and comparative examples (castor oil-modified polyol (1), castor oil-modified polyol (2), and castor oil). [Figure 2] Figure 2 shows the IR absorption spectrum of methyl oleate honey for reference. [Figure 3] Figure 3 shows an image illustrating the experiment on the heat resistance of this embodiment. [Figure 4] Figures 4(a) and 4(b) show images of the results of the heat resistance experiment for this embodiment. [Modes for carrying out the invention]

[0021] The embodiments of this disclosure (hereinafter referred to as "these embodiments") will be described in detail below, but the scope of this disclosure is not limited to the following description and can be implemented in various ways within the scope of its gist. [term] In this specification, "water pipe" refers to a general term for pipes through which a fluid containing water flows. Therefore, it includes distribution pipes, which deliver tap water from reservoirs, etc., to near homes; supply pipes, which branch off from near homes and reach faucets; conduit pipes, which send water pumped from dams, rivers, lakes, or wells to water treatment plants; transmission pipes, which send water to water treatment plants or reservoirs; drainage pipes, which send used water (wastewater) to sewage treatment plants; and pipes that deliver water to factories or places where people are active. In particular, the two-component curing type coating composition of this embodiment is especially preferred to form a film on the inner wall of drainage pipes.

[0022] In this specification, "organic group" refers to a group whose chemical structure is formed when an organic compound containing one or more carbon atoms takes the form of an n-valent group, and is an atomic group obtained by removing n hydrogen atoms from an organic compound containing one or more carbon atoms (where n is, for example, a natural number between 2 and 3). Therefore, for example, a divalent organic group refers to an atomic group obtained by removing 2 hydrogen atoms from an organic compound containing one or more carbon atoms.

[0023] In this specification, "alkyl group" may be linear, branched, or cyclic, and examples include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, tert-pentyl group, neopentyl group, 1,2-dimethylpropyl group, n-hexyl group, isohexyl group, (n-)heptyl group, (n-)octyl group, (n-)nonyl group, (n-)decyl group, (n-)undecyl group, (n-)dodecyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, or cyclononyl group. The aforementioned "alkyl group" includes a "cycloalkyl group," and examples of such "cycloalkyl groups" include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, or adamantyl group. Unless otherwise specified in this specification, "alkyl group" refers to an "alkyl group" with a predetermined number of carbon atoms as described above.

[0024] In this specification, "alkenyl group" refers to groups such as ethynyl group, 1-propynyl group (hereinafter also simply referred to as propenyl group), 2-propynyl group, 2-butynyl group, pentynyl group, hexynyl group, vinyl group, allyl group, or isopropenyl group. Unless otherwise specified in this specification, "alkenyl group" refers to a "alkoxy group" with a predetermined number of carbon atoms as described above.

[0025] In this specification, "alkoxy group" refers to, for example, a methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, pentyloxy group, hexyloxy group, 2-ethylhexyloxy group, octyloxy group, or nonyloxy group. Unless otherwise specified in this specification, "alkoxy group" refers to an "alkoxy group" with a predetermined number of carbon atoms as described above.

[0026] [Two-component curing composition for coating the inner walls of water pipes] This embodiment is a two-component curing type composition for coating the inner walls of water pipes, which hardens upon contact between a main component (A) (also simply referred to as (A) liquid) and a hardening agent (B) (also simply referred to as (B) liquid) to coat the inner walls of water pipes. Furthermore, the main component (A) contains an isocyanate compound (a1). Preferably, the isocyanate compound (a1) contains one or more types. The curing agent (B) contains a primary or secondary amine compound component (b1) and an alcohol component (b2) which includes a polyhydric alcohol compound (b2-1) having a cyclic hydrocarbon group and a hydroxyl value of 10 mg KOH / g or more and 1,500 mg KOH / g or less, and has a viscosity of 100 mPa·s or more and 500,000 mPa·s or less at 25°C. This allows for the formation of a coating that exhibits excellent curability in the low-temperature range (e.g., -9°C to -10°C) to the warm-temperature range (e.g., around 45°C), suppresses or prevents foaming during curing, maintains a predetermined hardness, and combines excellent elongation, high chemical resistance, and high heat resistance.

[0027] The main component (A) contains an isocyanate compound (a1), and the content of the isocyanate compound (a1) relative to the total main component (A) (100% by mass) is preferably 90% to 100% by mass, and more preferably 95% to 100% by mass. The main component (A) may contain one or more compounds selected from the group consisting of isocyanate compounds (a1). Furthermore, the main component (A) may contain additives as described below, if necessary. In this context, "the main component (A) consists substantially of only one or more isocyanate compounds (a1)" means that the components other than the isocyanate compounds (a1) contained in the main component (A) are less than 5% by mass, preferably less than 1% by mass.

[0028] The curing agent (B) contains a primary or secondary amine compound component (b1) and an alcohol component (b2), and the content of the primary or secondary amine compound component (b1) is preferably 10% to 80% by mass, and the content of the alcohol component (b2) is preferably 90% to 20% by mass, based on the total curing agent (B) (100% by mass). The curing agent (B) may also contain additives as described below, if necessary.

[0029] When using the two-component curing composition for coating the inner walls of water pipes according to this embodiment, and bringing the main component (A) and the curing agent (B) into contact to form a coating film on the inner wall of a water pipe, the mixing ratio of the main component (A) and the curing agent (B) (main component (A) / curing agent (B)) can be preferably 100 / 10 to 100 / 200, more preferably 100 / 20 to 100 / 150, even more preferably 100 / 40 to 100 / 120, and particularly preferably 100 / 50 to 100 / 100.

[0030] The main component (A) and the hardening agent (B) will be described below. (Main ingredient (A)) The main component (A) of this embodiment contains one or more isocyanate compounds (a1). Therefore, the main component (A) only needs to contain one or more isocyanate compounds (a1), and may further contain any additives described later as necessary. The total content of the isocyanate compound (a1) contained in the main component (A) is preferably 90% to 100% by mass, more preferably more than 94% to 100% by mass, even more preferably 98% to 100% by mass, and even more preferably less than 99% to 100% by mass, relative to the total amount of main component (A).

[0031] The viscosity of the main component (A) in this embodiment at 25°C is preferably 50 mPa·s or more and 1000 mPa·s or less. More preferably, the viscosity of the main component (A) at 25°C is 50 mPa·s or more and 500 mPa·s or less, and even more preferably 50 mPa·s or more and 200 mPa·s or less. When the viscosity of the main component (A) at 25°C is within the above range, it exhibits the effect of low viscosity when mixed with the curing agent, thereby improving the applicability. In this specification, the viscosity at 25°C is calculated by measuring the viscosity of the sample at 25°C using a B-type viscometer. Specifically, as described in the Examples section below, the viscosity measurement in this specification was performed in accordance with JIS K 7117-1:1999, using a B-type viscometer at a measurement temperature of 25°C, with the main component (A) and hardener (B) set up separately and the viscosity measured after 2 minutes.

[0032] The total molecular weight of the main component (A) in this embodiment is preferably in the range of 200 to 2000, more preferably in the range of 200 to 1000, even more preferably in the range of 300 to 700, and particularly preferably in the range of 200 to 500. In this specification, the molecular weight was calculated using GPC (Glycerin Protection Spectrum) on a polystyrene basis, as described in the examples below.

[0033] The main component (A) of this embodiment is a component comprising one or more isocyanate compounds (a1), preferably composed of one to five isocyanate compounds (a1), more preferably composed of one to four isocyanate compounds (a1), and even more preferably composed of one to three isocyanate compounds (a1). The main component (A) may also be composed of one isocyanate compound (a1) alone.

[0034] <Isocyanate compound (a1)> The isocyanate compound (a1) in this embodiment is not particularly limited as long as it is a compound having two or more isocyanate groups. Furthermore, the isocyanate compound (a1) may be a compound that has been partially trimmed using a trimerizing catalyst, or a compound that has been partially allophanated using an allophanating catalyst, or it may be a compound that has been prepolymerized using a known polyol or the like as a modifier. From the viewpoint of curability, the isocyanate compound (a1) in this embodiment is preferably an aromatic isocyanate compound having an aromatic ring, and more preferably an aromatic isocyanate compound having an aromatic ring and two or more isocyanate groups. If the isocyanate compound (a1) in this embodiment is an aromatic isocyanate compound, it is thought that the presence of an aromatic ring improves hydrophobicity and suppresses foaming.

[0035] The isocyanate compound (a1) of this embodiment preferably contains one or more compounds represented by the following general formula (1). [ka] (In the above general formula (1), M represents an n-valent organic group having 4 or more carbon atoms, L independently represents a single bond or an alkylene group having 1 to 3 carbon atoms, and n is an integer of 2 or more.)

[0036] In the above general formula (1), M is an organic group having 4 to 40 carbon atoms, preferably an organic group having 5 to 30 carbon atoms, and more preferably an organic group having 6 to 24 carbon atoms. A carbon number of 4 to 40 for M is preferable from the viewpoint of curability. In the above general formula (1), each L is independent, and the n Ls may be the same or different from one another. Examples of alkylene groups having 1 to 3 carbon atoms include the methylene group, ethylene group, n-propylene group, or propane-2-ylidene group. In the above general formula (1), n ​​is preferably an integer between 2 and 5, more preferably an integer between 2 and 4, and even more preferably an integer between 2 and 3. When the value of n is an integer between 2 and 5, the polyhydric alcohol compound (b2-1) and / or primary or secondary amine compound component (b1) in the curing agent (B) can bond with multiple isocyanate groups, resulting in excellent curing properties.

[0037] In the above general formula (1), the preferred organic group is specifically an n-valent group having a hydrocarbon group, preferably a linear or branched saturated hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group having an aromatic ring, or a cyclic hydrocarbon group in which two or more aromatic rings are linked by a linking group (e.g., an alkylene group), and more preferably an aromatic hydrocarbon group having an aromatic ring or a cyclic hydrocarbon group in which two or more aromatic rings are linked by a linking group (e.g., an alkylene group).

[0038] The linear or branched saturated hydrocarbon group is preferably an alkylene group having 4 to 10 carbon atoms. Examples of such alkylene groups include 1,1-dimethylethylene, 1,2-dimethylethylene, 1,4-butanediyl, butane-2,3-diyl, 1-methylpropylene, 2-methylpropylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, trimethylhexamethylene, and decamethylene.

[0039] Preferred alicyclic hydrocarbon groups include cyclohexanediyl group, cyclooctanediyl group, cyclononanediyl group, bicyclohexanediyl group, bicyclooctanediyl group, bicyclononanediyl group, methylenebis(cyclohexane-1,4-diyl) group, methylenebis(cyclohexane-1,2-diyl), methylenebis(cyclohexane-1,3-diyl), and divalent polycyclic alicyclic hydrocarbon groups such as adamantanediyl group, norbornane group, or isobornane group. In the alicyclic hydrocarbon group, one or more hydrogen atoms in the alicyclic hydrocarbon group may be substituted with substituents. Examples of substituents include alkyl groups having 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms), such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups; aromatic hydrocarbon groups having 6 to 10 carbon atoms, such as phenyl and naphthyl groups; and halogen atoms such as fluorine, chlorine, bromine, and iodine atoms.

[0040] The aromatic hydrocarbon group having the aromatic ring can be any hydrocarbon group having one or more aromatic rings. Herein, the term "aromatic ring" as used herein includes monocyclic aromatic rings, fused aromatic rings, or aromatic ring aggregates. Examples of monocyclic aromatic rings include benzene, furan, pyrrole, thiophene, imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, pyridine, pyrimidine, pyridazine, pyrazine, and triazine. Examples of fused aromatic rings include naphthalene, anthracene, phenalene, phenanthrene, quinoline, isoquinoline, quinazoline, phthalazine, pteridine, coumarin, indole, benzimidazole, benzofuran, and acridine. Examples of ring aggregate aromatic rings include biphenyl, binaphthalene, bipyridine, bithiophene, phenylpyridine, phenylthiophene, terphenyl, diphenylthiophene, and quaterphenyl.

[0041] Furthermore, in the aromatic hydrocarbon group having the aromatic ring, one or more hydrogen atoms in the aromatic ring may be substituted with substituents. Examples of substituents include alkyl groups having 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms); alkenyl groups having 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms); alkoxy groups having 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms); and halogen atoms such as fluorine, chlorine, bromine, and iodine.

[0042] Examples of aromatic hydrocarbon groups having the aromatic ring include groups represented by the following formulas (i-1) to (i-5). [ka] (In the above equations (i-1) to (i-5), R 1 , R 2 and R 5 Each of these independently represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, L 1 The 'n' represents a single bond or an alkylene group with 1 to 3 carbon atoms, n1 and n2 each independently represent integers from 0 to 4, and n5 represents an integer from 0 to 6. * represents the bond that combines with L in the general formula (1) above. The cyclic hydrocarbon group in which the two or more aromatic rings are linked by a linking group (e.g., an alkylene group) is preferably represented by the following formula (i-6). [ka] (In the above formula (i-6), R 3 and R 4 Each of these independently represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, L 3 and L 4 The 'n' represents a linking group, for example, a single bond or an alkylene group with 1 to 3 carbon atoms; n3 independently represents an integer from 0 to 4; n4 independently represents an integer from 0 to 3; and m1 represents the degree of polymerization, for example, an integer from 0 to 3. Note that * represents the bond that connects to L in the general formula (1) above.

[0043] The isocyanate compound (a1) in this embodiment may be, for example, a carbodiimide-modified MDI (for example, the carbodiimide-modified MDI described in Japanese Patent Publication No. 5041794), which is obtained by modifying the compound represented by the general formula (1) with carbodiimide.

[0044] The molecular weight of the isocyanate compound (a1) in this embodiment is preferably in the range of 100 to 1000, more preferably in the range of 200 to 800, even more preferably in the range of 200 to 600, and particularly preferably in the range of 200 to 500. In this specification, the molecular weight was calculated using GPC (Glycerin Protection Spectrum) on a polystyrene basis, as described in the examples below.

[0045] In this embodiment, the isocyanate compound (a1) preferably includes an aromatic isocyanate compound having an aromatic ring. From the viewpoint of curability and elongation, an aromatic isocyanate compound having an aromatic ring is used as the isocyanate compound (a1).

[0046] The isocyanate compound (a1) of this embodiment preferably contains an aromatic isocyanate compound represented by the following general formula (2). [Chemical formula] (In the above general formula (2), R 1 , R 2 and R 3 each independently represent an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, and L 1 and L 2 each independently represent a single bond or an alkylene group having 1 to 3 carbon atoms. n1 and n2 each independently represent an integer of 0 to 4, n3 each independently represents an integer of 0 to 3, m2 represents the degree of polymerization, and represents an integer of 0 to 3 or more.) In the above general formula (2), m2 is preferably in the range of 0 to 4, more preferably in the range of 0 to 3, and even more preferably in the range of 0 to 2. By containing the isocyanate compound (a1) represented by the above general formula (2) as the main component (A), the foaming suppression effect tends to be further improved. In particular, since the isocyanate compound (a1) represented by the above general formula (2) contains many aromatic rings, it is considered that the hydrophobicity is further improved and the foaming suppression effect is further improved.

[0047] The isocyanate compound (a1) of this embodiment preferably contains 2 to 5 aromatic isocyanate compounds having an aromatic ring. Thereby, the curability and elongation can be further improved.

[0048] In particular, the isocyanate compound (a1) of this embodiment is preferably a mixture mainly containing an aromatic isocyanate (a1-1) represented by the following general formula (2-1) and an aromatic isocyanate (a1-2) represented by the following general formula (2-2). Thereby, it shows better curability in the low temperature range, suppresses or prevents foaming during curing, and can form a coating film with better chemical resistance. In this specification, "contains as a main component" means that a predetermined component is contained in an amount of 50% by mass or more and 100% by mass or less (preferably 95% by mass or more and 100% by mass or less) of the whole. Therefore, for example, "contains as a main component an aromatic isocyanate (a1-1) represented by the following general formula (2-1) and an aromatic isocyanate (a1-2) represented by the following general formula (2-2)" means that the total content of the aromatic isocyanate (a1-1) represented by the following general formula (2-1) and the aromatic isocyanate (a1-2) represented by the following general formula (2-2) accounts for 50% by mass or more and 100% by mass or less (preferably 95% by mass or more and 100% by mass or less) of the whole isocyanate compound (a1). [ka] (In the above general formula (2-1), R 1 , R 2 and R 3 Each of these independently represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, L 1 and L 2 Each of the following independently represents a single bond or an alkylene group with 1 to 3 carbon atoms; n1 and n2 independently represent integers from 0 to 4; n3 independently represents integers from 0 to 3; and p represents the degree of polymerization, also representing an integer from 0 to 3. [ka] (In the above general formula (2-2), R 1 and R 2 Each of these independently represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, L 1 (where n1 represents a single bond or an alkylene group with 1 to 3 carbon atoms, and n1 and n2 independently represent integers from 0 to 4.) The main component (A) of this embodiment contains an aromatic isocyanate compound represented by the general formula (2-2) above, which tends to reduce the viscosity of the mixture with the curing agent (B) and moderately suppress the reaction rate. In the aromatic isocyanate compound represented by the general formula (2-2) above, the positional relationship of the two benzene rings is such that the isocyanate group attached to one benzene ring has the other benzene ring at either the ortho, meta, or para position. 1 They can be connected via this.

[0049] The content of aromatic isocyanate (a1-1) represented by general formula (2-1) may be preferably 40% to 90% by mass, more preferably 45% to 90% by mass, even more preferably 50% to 90% by mass, and even more preferably 55% to 90% by mass, relative to the total main component (A). The content of aromatic isocyanates (a1-2) represented by general formula (2-2) may be preferably 5% to 40% by mass, more preferably 5% to 35% by mass, even more preferably 5% to 30% by mass, and even more preferably 5% to 25% by mass, relative to the total main component (A).

[0050] In this embodiment, if the isocyanate compound (a1) is a mixture mainly comprising an aromatic isocyanate (a1-1) represented by the general formula (2-1) and an aromatic isocyanate (a1-2) represented by the general formula (2-2), the mixing ratio ((a1-1) / (a1-2)) of the aromatic isocyanate (a1-1) to the aromatic isocyanate (a1-2) is preferably in the range of 100 / 0 to 60 / 40, more preferably in the range of 100 / 0 to 70 / 30, and even more preferably in the range of 100 / 0 to 80 / 20. A mixing ratio of the aromatic isocyanate (a1-1) and the aromatic isocyanate (a1-2) within the above range is preferable from the viewpoint of curability and handling.

[0051] Furthermore, the aromatic isocyanate compound (a1-2) of this embodiment preferably contains as a main component one or more compounds selected from the group consisting of compounds represented by the following general formulas (3-1) and (3-2). [ka] [ka] (In the above general formulas (3-1) and (3-2), R 1 and R 2 Each of these independently represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, L 1 (where n1 represents a single bond or an alkylene group with 1 to 3 carbon atoms, and n1 and n2 independently represent integers from 0 to 4.)

[0052] The aromatic isocyanate compound (a1-2) is particularly preferably one or more selected from the group consisting of compounds represented by the following general formula (3-1.1) and compounds represented by the following general formula (3-2.1). [ka] [ka] (In the above general formulas (3-1.1) and (3-2.1), R 1 and R 2 Each of the following independently represents an alkyl group with 1 to 5 carbon atoms, an alkenyl group with 1 to 5 carbon atoms, or an alkoxy group with 1 to 5 carbon atoms, and each of the following independently represents an integer from 0 to 4.

[0053] <Preferred form of the main component (A)> The main component (A) of this embodiment may consist substantially only of an isocyanate compound (a1) and any additives described later. The isocyanate compound (a1) is a mixture mainly comprising an aromatic isocyanate (a1-1) represented by the general formula (2-1) and an aromatic isocyanate (a1-2) represented by the general formula (2-2), and the mixing ratio of the aromatic isocyanate (a1-1) to the aromatic isocyanate (a1-2) ((a1-1) / (a1-2)) is preferably in the range of 80 / 10 to 10 / 80. This allows for better curing properties at low temperatures, further suppression or prevention of foaming during curing, and the formation of a coating with superior chemical resistance.

[0054] (Hardening agent (B)) The curing agent (B) of this embodiment contains a primary or secondary amine compound component (b1) and an alcohol component (b2) which includes a polyhydric alcohol compound (b2-1) having a hydroxyl value of 10 mg KOH / g or more and 1,500 mg KOH / g or less and having a cyclic hydrocarbon group. Furthermore, the curing agent (B) may contain any additives described later as necessary. The primary or secondary amine compound component (b1) is a component comprising one or more amine compounds. The amine compound is a compound having two or more amino groups (primary amine (-NH2) and / or secondary amine (-NH-)). Similarly, the alcohol component (b2) is a component that includes a polyhydric alcohol compound (b2-1), which is an essential component, and other alcohol compounds (b2-2), which are optional components. The total content of the primary or secondary amine compound component (b1) relative to the total curing agent (B) of this embodiment may be preferably 5% to 90% by mass, more preferably 10% to 80% by mass, even more preferably 12% to 70% by mass, even more preferably 15% to 60% by mass, and particularly preferably 20% to 40% by mass. The total content of the alcohol component (b2) relative to the entire curing agent (B) is preferably 10% to 95% by mass, more preferably 30% to 90% by mass, even more preferably 40% to 85% by mass, and even more preferably 50% to 80% by mass. The content of the polyhydric alcohol compound (b2-1) relative to the total curing agent (B) is preferably 10% to 95% by mass, more preferably 30% to 90% by mass, even more preferably 40% to 85% by mass, and even more preferably 50% to 80% by mass. In this embodiment, the content of the polyhydric alcohol compound (b2-1) relative to the total alcohol component (b2) is preferably 50% to 100% by mass, more preferably 60% to 100% by mass, even more preferably 70% to 100% by mass, and even more preferably 80% to 100% by mass.

[0055] In the curing agent (B) according to the embodiment, the total content of the primary or secondary amine compound component (b1) and the polyhydric alcohol compound (b2-1) is preferably 50% to 100% by mass, more preferably 60% to 100% by mass, even more preferably 70% to 100% by mass, even more preferably 80% to 100% by mass, even more preferably 85% to 100% by mass, even more preferably 90% to 100% by mass, and particularly preferably 95% to 100% by mass, relative to the total curing agent (B). In another embodiment, the total content of the primary or secondary amine compound component (b1) and the polyhydric alcohol compound (b2-1) is preferably 50% to less than 100% by mass, more preferably 60% to 99% by mass, even more preferably 70% to 98% by mass, even more preferably 80% to 96% by mass, even more preferably 85% to 94% by mass, and even more preferably 90% to 92% by mass, relative to the total curing agent (B). In the curing agent (B) according to the embodiment, the total content of the primary or secondary amine compound component (b1), the polyhydric alcohol compound (b2-1), and any additive described later is preferably 60% to 100% by mass, more preferably 70% to 100% by mass, even more preferably 80% to 100% by mass, even more preferably 85% to 100% by mass, even more preferably 90% to 100% by mass, even more preferably 95% to 100% by mass, and particularly preferably 97% to 100% by mass, relative to the total curing agent (B).

[0056] The viscosity of the curing agent (B) in this embodiment at 25°C is preferably 100 mPa·s or more and 500,000 mPa·s or less. More preferably, the viscosity of the curing agent (B) at 25°C is 100 mPa·s or more and 50,000 mPa·s or less, even more preferably 1,500 mPa·s or more and 10,000 mPa·s or less, even more preferably 1,000 mPa·s or more and 5,000 mPa·s or less, and particularly preferably 3,000 mPa·s or more and 4,500 mPa·s or less. When the viscosity of the curing agent (B) at 25°C is within the above range, it exhibits excellent conformability to the shape of the water pipe.

[0057] The total molecular weight of the curing agent (B) in this embodiment is preferably in the range of 100 to 2000, more preferably in the range of 200 to 1500, even more preferably in the range of 300 to 1200, and particularly preferably in the range of 500 to 1000. In this specification, the molecular weight was calculated using GPC (Glycerin Protection Spectrum) on a polystyrene basis, as described in the examples below.

[0058] <Primary or secondary amine compound component (b1)> The primary or secondary amine compound component (b1) of this embodiment preferably contains one or more compounds having two or more amino groups (primary amine (-NH2) and / or secondary amine (-NH-)). The primary or secondary amine compound component (b1) of this embodiment preferably contains one or more selected from the group consisting of a first amine compound (b1-1) that does not have an ester bond or a cyclic group and a second amine compound (b1-2) that has a chemical structure other than the first amine compound (b1-1). It is more preferably that it contains the first amine compound (b1-1) and the second amine compound (b1-2), and even more preferably that it consists of the first amine compound (b1-1) and the second amine compound (b1-2). When the curing agent (B) contains the first amine compound (b1-1), it provides the effect of imparting flexibility to the coating film. On the other hand, when the curing agent (B) contains the second amine compound (b1-2), it provides the effect of imparting low-temperature curability to the coating film. When both the first amine compound (b1-1) and the second amine compound (b1-2) are contained in the curing agent (B), a coating with high hardness and a predetermined crosslinking density can be formed during curing with the main component (A), thus providing superior curability.

[0059] In this embodiment, the content of the first amine compound (b1-1) is preferably 0% to 100% by mass, more preferably 10% to 90% by mass, even more preferably 20% to 80% by mass, even more preferably 25% to 75% by mass, even more preferably 30% to 70% by mass, even more preferably 32% to 65% by mass, and particularly preferably 35% to 65% by mass, relative to the total amount of the primary or secondary amine compound component (b1). In this embodiment, the content of the second amine compound (b1-2) is preferably 0% to 100% by mass, more preferably 10% to 90% by mass, even more preferably 20% to 80% by mass, even more preferably 25% to 75% by mass, even more preferably 30% to 70% by mass, even more preferably 35% to 65% by mass, and particularly preferably 35% to 65% by mass, relative to the total amount of the primary or secondary amine compound component (b1).

[0060] <<First amine compound (b1-1)>> The first amine compound (b1-1) of this embodiment may be any compound having either an -NH2 or -NH- amino group and not having an ester bond or a cyclic group. When the curing agent (B) contains the first amine compound (b1-1), it provides the effect of imparting flexibility to the coating film. The first amine compound (b1-1) in this embodiment is an alkylene oxide group [-(CHR) nb -O-] mbIt is preferable that the compound has at least two amino groups (-NH2). The alkylene oxide group [-(CHR) nb -O-] mb The R inside represents a hydrogen atom or an alkyl group with 1 to 3 carbon atoms. Also, an alkylene oxide group [-(CHR) nb -O-] mb In the given range, nb represents an integer between 1 and 5, and mb preferably represents an integer between 3 and 1,000, more preferably between 3 and 300.

[0061] The first amine compound (b1-1) is preferably, for example, a polyetheramine compound. By including a polyetheramine compound as the first amine compound (b1-1) in the curing agent (B), the flexibility of the cured product after curing is further improved. This is thought to further improve the conformability to the shape of the water pipe and the elongation. Examples of such polyetheramine compounds include primary polyetherdiamines (2 functional groups, e.g., molecular weight 1500-2500), primary polyethertriamines (3 functional groups, e.g., molecular weight 1500-2500), poly(propylene glycol)triamine (CAS number: 64852-22-8), secondary polyetherdiamines, or secondary polyethertriamines. When the curing agent (B) contains the polyetheramine compound exemplified above as the first amine compound (b1-1), surface hardening is accelerated, and toughness and elongation tend to improve. The primary polyetherdiamine is preferably a compound represented by the following formula (b1-1). [ka] (In the above formula (b1-1), nb1 independently represents an integer between 0 and 80, preferably between 28 and 78.) The primary polyethertriamine is preferably a compound represented by the following formula (b1-2). [ka] (In the above formula (b1-2), nb2, nb3, and nb4 each independently represent an integer between 0 and 30.) The molecular weight (weight-average molecular weight) of the first amine compound (b1-1) in this embodiment is preferably in the range of 500 to 3000, more preferably in the range of 500 to 2500, and even more preferably in the range of 1000 to 2000.

[0062] The first amine compound (b1-1) of this embodiment preferably contains a primary amine and / or a secondary amine. More specifically, the first amine compound (b1-1) of this embodiment preferably contains one or more selected from the group consisting of a primary amine compound (i) containing a primary amine and a secondary amine compound (ii) containing a secondary amine. Examples of the primary amine compound (i) include primary polyetherdiamine (2 functional groups, molecular weight 1500-2500), primary polyethertriamine (3 functional groups, molecular weight 1500-2500), poly(propylene glycol)triamine (CAS number: 64852-22-8), and polyoxypropylenediamine. Similarly, the secondary amine compound (ii) may be a secondary polyetherdiamine or a secondary polyethertriamine (see, for example, the secondary polyetheramines described in Japanese Patent Publication No. 2010-511639). In the first amine compound (b1-1) of this embodiment, the mixing ratio of the primary amine compound (i) and the secondary amine compound (ii) (primary amine compound (i) / secondary amine compound (ii)) is preferably in the range of 90 / 10 to 100 / 0, and more preferably in the range of 95 / 5 to 100 / 0. Furthermore, in addition to the primary amine compound (i), the first amine compound (b1-1) of this embodiment may further contain a secondary amine compound (ii) and / or a known tertiary amine, as long as the purpose or effects of this disclosure are not impaired. In this case, the proportion of the primary amine compound (i) in the total first amine compound (b1-1) is preferably 90% by mass or more, more preferably 94% by mass or more, and even more preferably 100% by mass. By setting the proportion of the primary amine compound (i) in the total first amine compound (b1-1) within the above range, the reactivity with the main component (A) can be improved. As a result, a composition with excellent curability can be obtained.

[0063] <<Second amine compound (b1-2)>> The second amine compound (b1-2) in this embodiment may be any compound other than the first amine compound and having either an -NH2 or -NH- amino group. That is, the second amine compound (b1-2) is a compound having either an -NH2 or -NH- amino group and excluding the first amine compound. The presence of a second amine compound (b1-2) as the curing agent (B) provides the effect of imparting low-temperature curability to the coating film. The second amine compound (b1-2) in this embodiment is preferably one or more selected from the group consisting of amino acid ester compounds or amino acid ester derivative compounds and cyclic amine compounds.

[0064] - Amino acid ester compounds or amino acid ester derivative compounds - The amino acid ester compound or amino acid ester derivative compound of this embodiment may be any compound having a chemical structure in which one or more hydrogen atoms of a carboxyl group (-COOH) in an amino acid molecule are substituted with an alkyl group having 1 to 8 carbon atoms. Furthermore, the term "amino acid" is a general term for compounds having an amino group (including -NH2, -NH-, and ≡N) and a carboxyl group in the same molecule. Therefore, any amino acid can be used as a precursor for the amino acid ester compound or amino acid ester derivative compound of this embodiment, which is classified into α-amino acids, β-amino acids, γ-amino acids, and δ-amino acids based on the position of the carbon atom to which the amino group is attached relative to the carbon atom to which the carboxyl group is attached. In addition, α-amino acids have an asymmetric carbon and are classified into L-isomers and D-isomers based on their stereochemistry, and either of these, or a racemic mixture of both, can be used as the amino acid. The presence of an amino acid ester compound or amino acid ester derivative compound in the curing agent (B) improves low-temperature curing performance. In particular, when an amino acid ester compound or amino acid ester derivative compound is included as the second amine compound (b1-2), the reaction is accelerated by moisture in the air, and surface hardening is accelerated, preventing moisture intrusion and thus suppressing foaming more efficiently. Furthermore, due to its high reactivity, the reaction with isocyanate in the low-temperature range is further accelerated, which is thought to further improve curing performance. In this embodiment, α-amino acids or β-amino acids are preferred as the amino acids, from the viewpoint of the curing reaction with the main component (A). The amino acids that are precursors to the amino acid ester compounds or amino acid ester derivative compounds of this embodiment are mainly components derived from natural products and are classified into neutral amino acids (monoaminomonocarboxylic acids), acidic amino acids (monoaminodicarboxylic acids), and basic amino acids (diaminomonocarboxylic acids, etc.). Specific examples of neutral amino acids include glycine, alanine, valine, leucine, isoleucine, serine, threonine, cysteine, cystine, methionine, phenylalanine, tyrosine, tryptophan, glutamine, or proline. Specific examples of acidic amino acids include glutamic acid or aspartic acid. Specific examples of basic amino acids include lysine, arginine, ornithine, or histidine.

[0065] In particular, a preferred form of the amino acid ester compound or amino acid ester derivative compound of this embodiment is a compound in which one or more hydrogen atoms of the carboxyl group of an amino acid are substituted with an alkyl group having 1 to 8 carbon atoms, and which has a substructure of the following general formula (I). [ka] (In the general formula (I) above, * represents a bond with a carbon atom.) This further improves low-temperature curing properties.

[0066] The amino acid ester compound or amino acid ester derivative compound of this embodiment is preferably, for example, a compound represented by the following general formula (I.1). [ka] (In the above general formula (I.1), M I is, n I R represents a hydrocarbon group with 1 to 28 carbon atoms in valence. I1 Each of these independently represents an alkyl group having 1 to 30 carbon atoms, wherein one or more -CH2- in the alkyl group may be substituted with -O-, -C(=O)-, -OC(=O)-, or -C(=O)-O-, RI2 n represents an alkyl group with 1 to 6 carbon atoms. I (This represents an integer between 1 and 4, inclusive.)

[0067] In the above general formula (I.1), M I Preferably, it is a hydrocarbon group having 1 to 18 carbon atoms and having a 1 to 4 valent charge, and more preferably a hydrocarbon group having 1 to 16 carbon atoms and having a 1 to 3 valent charge. Therefore, in the above general formula (I.1), n I The integer is preferably between 1 and 3. The hydrocarbon group in question is, similar to the "organic group" described above, an organic compound containing one or more carbon atoms from which a hydrogen atom has been removed. I This refers to an atomic group formed by removing n atoms. Therefore, the hydrocarbon group is preferably a linear or branched saturated hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group having an aromatic ring, or a cyclic hydrocarbon group in which two or more aromatic rings are linked by a linking group (e.g., an alkylene group), with n bonds. I It may be a group having a single element. The contents of the linear or branched saturated hydrocarbon group, the alicyclic hydrocarbon group, the aromatic hydrocarbon group having an aromatic ring, and the cyclic hydrocarbon group in which two or more aromatic rings are linked by a linking group (e.g., an alkylene group) are the same as described above.

[0068] In the above general formula (I.1), R I1 Each of these independently represents an alkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, wherein one or more -CH2- in the alkyl group may be substituted with -O-, -C(=O)-, -OC(=O)-, or -C(=O)-O-. I1 For example, R I3 -O-(O=)C-(CH2) m4 -(R I3 ) represents an alkyl group having 1 to 5 carbon atoms, and m4 represents an integer from 0 to 4.

[0069] The compound represented by the above general formula (I.1) is n IWhen the value is 2, it is preferable that the compound is an amino acid ester compound or amino acid ester derivative compound represented by the following general formula (I.2). [ka] (In the above general formula (I.2), M I R represents a divalent hydrocarbon group with 1 to 18 carbon atoms. I1 Each of these independently represents an alkyl group having 1 to 15 carbon atoms, wherein one or more -CH2- in the alkyl group may be substituted with -O-, -C(=O)-, -OC(=O)-, or -C(=O)-O-, R I2 n represents an alkyl group with 1 to 6 carbon atoms. I (This represents an integer between 1 and 4, inclusive.)

[0070] Examples of hydrocarbon groups in the above general formula (I.2) include 1,1-dimethylethylene group, 1,2-dimethylethylene group, 1,4-butanediyl group, 2-methyl-1,5-pentanediyl group, butane-2,3-diyl group, 1-methylpropylene group, 2-methylpropylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, trimethylhexamethylene group, decamethylene group, cyclohexanediyl group, Preferred hydrocarbon groups include divalent monocyclic alicyclic hydrocarbon groups such as cyclooctanediyl, cyclononanediyl, bicyclohexanediyl, bicyclooctanediyl, bicyclononanediyl, methylenebis(cyclohexane-1,4-diyl), methylenebis(cyclohexane-1,2-diyl), and methylenebis(cyclohexane-1,3-diyl), as well as divalent polycyclic alicyclic hydrocarbon groups such as adamantanediyl, norbornane, or isobornane. In addition, one or more hydrogen atoms in the hydrocarbon group may be substituted with substituents. Examples of substituents include alkyl groups having 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms), such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups; aromatic hydrocarbon groups having 6 to 10 carbon atoms, such as phenyl and naphthyl groups; and halogen atoms such as fluorine, chlorine, bromine, and iodine atoms. In the above general formula (I.2), R I1 is, -(CH2) p -C(=O)-OR I3 It is preferable that R I3 represents an alkyl group with 1 to 8 carbon atoms, and p represents an integer between 0 and 5 (inclusive).

[0071] -Cyclic amine compounds- The cyclic amine compound in this embodiment is preferably a compound represented by the following general formula (II). [ka] (In the above general formula (II), R II1 and R II2 Each of these independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, M 1 is either unsubstituted or substituted with R II3 This represents a cyclic group which may be substituted with one or more substituents. II3 These include alkyl groups having 1 to 10 carbon atoms, halogen atoms, -SH, hydroxyl groups, and -SR. II4 (R II4 ) represents an alkyl group having 1 to 3 carbon atoms. ) represents one or more selected from the group consisting of ). In the above general formula (II), R II1 and R II2 Each of these is preferably a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms.

[0072] In the above general formula (II), M 1 is either unsubstituted or substituted with R II3 It is preferable to represent a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, or a divalent cyclic group represented by the following general formula (II-1), which may be substituted one or more times by the above. [ka] (In the above general formula (II-1), M 2 and M 3Each of these independently represents a phenylene group or a cyclohexylene group, L II1 The symbol represents a linking group, which is either a single bond or an alkylene group having 1 to 50 carbon atoms, where one or more -CH2- atoms in the alkylene group may be substituted with -O-, -C(=O)-, -OC(=O)-, or -C(=O)-O-. Note that the * in the above general formula (II-1) is bonded to the nitrogen atom in the above general formula (II).

[0073] In the above general formula (II-1), L II1 These are single bonds, alkylene groups with 1 to 10 carbon atoms, alkylene oxy groups, and -C(=O)-O-(CH2) n6 -O-(O=)C-(n6 represents an integer between 1 and 5, inclusive) or -C(=O)-O-[(CH2)] n7 -O] m6 It is preferable that -(O=)C-(n7 represents an integer between 1 and 5, and m6 represents an integer between 1 and 20). Examples of the alkylene oxy group include -[(CH2) n5 -O] m5 -(n5 preferably represents an integer between 1 and 5, and m5 preferably represents an integer between 1 and 15. Furthermore, m5 is preferably between 1 and 11, more preferably between 2 and 7, and even more preferably between 3 and 5. Furthermore, the value of m6 is preferably 1 to 10, more preferably 2 to 8, and even more preferably 3 to 6.

[0074] The cyclic amine compound in this embodiment is preferably one or more selected from the group consisting of monocyclic aromatic diamine compounds, cyclic aggregated aromatic diamine compounds, and alicyclic amine compounds. More specifically, preferred forms of the cyclic amine compound of this embodiment include one or more selected from the group consisting of monocyclic aromatic diamine compounds represented by the following general formula (II.1), ring-assembled aromatic diamine compounds represented by the following general formula (II.2), and alicyclic amine compounds represented by the following general formula (II.3). [ka] (In the general formula (II.1), R II5 each independently represents an alkyl group having 1 to 5 carbon atoms, -SH, a hydroxyl group, and -S-R II4 (where R II4 represents an alkyl group having 1 to 3 carbon atoms.) represents, and n II1 represents an integer of 0 or more and 4 or less.) [Chemical formula] (In the general formula (II.2), R II6 and R II7 each independently represents one or more selected from the group consisting of a halogen atom, an alkyl group having 1 to 8 carbon atoms, and a halogen atom, and L II1 is a linking group and represents a single bond or an alkylene group having 1 to 50 carbon atoms, provided that one or more -CH2- in the alkylene group may be substituted with -O-, -C(=O)-, -O-C(=O)-, or -C(=O)-O-, and n II2 and n II3 each independently represents an integer of 0 or more and 4 or less.) [Chemical formula] (In the general formula (II.3), R II1 and R II2 each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and L II2 is a linking group and represents a single bond or an alkylene group having 1 to 6 carbon atoms, R II8 and R II9 each independently represents one or more selected from the group consisting of alkyl groups having 1 to 8 carbon atoms, and n II2 and n II3 each independently represents an integer of 0 or more and 4 or less.)

[0075] In the monocyclic aromatic diamine compound represented by the general formula (II.1), R II5 in the general formula (II.1) each independently represents an alkyl group having 1 to 5 carbon atoms or -S-R II4 (where R II4(which represents an alkyl group having 1 to 3 carbon atoms) is preferable.

[0076] In the polycyclic aromatic diamine compound represented by the above general formula (II.2), L in the above general formula (II.2) II1 is an alkylene group having 1 to 5 carbon atoms, -[(CH2) n5 -O] m5 -(n5 represents an integer of 1 or more and 3 or less, m5 is an integer of 1 or more and 30 or less, preferably 1 or more and 10 or less, more preferably 2 or more and 8 or less, still more preferably 3 or more and 6 or less).), -C(=O)-O-(CH2) n6 -O-(O=)C-(n6 represents an integer of 1 or more and 5 or less.) or -C(=O)-O-[(CH2) n7 -O] m6 -(O=)C-(n7 represents an integer of 1 or more and 5 or less, and m6 is 1 or more and 30 or less, preferably 1 or more and 10 or less, more preferably 2 or more and 8 or less, still more preferably 3 or more and 6 or less) is preferable.

[0077] In the alicyclic amine compound represented by the above general formula (II.3), in the general formula (II.3), R II1 and R II2 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and L II2 represents a single bond or an alkylene group having 1 to 3 carbon atoms, and R II8 and R II9 each independently represent one or more selected from the group consisting of alkyl groups having 1 to 3 carbon atoms, and n II2 and n II3 each independently preferably represent an integer of 0 or more and 2 or less. When the curing agent (B) contains an alicyclic amine compound, it tends to promote surface curing when it comes into contact with the main agent (A).

[0078] A preferred form of the second amine compound (b1-2) in this embodiment is one or more selected from the group consisting of an amino acid ester compound or amino acid ester derivative compound represented by the general formula (I.1), a monocyclic aromatic diamine compound represented by the general formula (II.1), a ring-assembled aromatic diamine compound represented by the general formula (II.2), and an alicyclic amine compound represented by the general formula (II.3). Specific examples of preferred compounds of the second amine compound (b1-2) include, for example, N,N-(methylenedi-4,1-cyclohexanediyl)bis-tetraethyl ester (or N,N'-[methylenebis(cyclohexane-4,1-diyl)]bisaspartate tetraethyl, CAS number: 136210-30-5), N,N-methylenebis(2-methyl-4,1-cyclohexanediyl)bis-tetraethyl ester (or N,N'-[methylenebis(2-methyl-4,1-cyclohexanediyl)]bis(aspartate diethyl, CAS number: 136210-32-7), N,N'-(2-methyl- It may be one or more selected from the group consisting of 1,5-pentanediyl)bis-,1,1',4,4'-tetraethyl ester) (CAS number: 168253-59-6), diethyltoluenediamine, dimethylthiotoluenediamine, 4,4'-methylenebis[N-sec-butylaniline], N,N'-bis(1-methylpropyl)-1,4-phenylenediamine, 4,4'-methylenebisN-(1-methylpropyl)-cyclohexamine, 4,4'-methylenebis(2-chloroaniline), 4,4'-methylenebis(2-ethyl-6-methylaniline), N,N'-di-sec-butyl-4,4'-methylenebis(cyclohexylamine)), and trimethylenebis(4-aminobenzoate) or poly(1,4-butanediol)bis(4-aminobenzoate). When the curing agent (B) contains the second amine compound (b1-2) as exemplified above, it tends to accelerate surface hardening when it comes into contact with the main component (A). The molecular weight of the second amine compound (b1-2) in this embodiment is preferably in the range of 100 to less than 1000, more preferably in the range of 200 to 800, even more preferably in the range of 300 to 700, and particularly preferably in the range of 400 to 600.

[0079] <<Preferred form of primary or secondary amine compound component (b1)>> The primary or secondary amine compound component (b1) of this embodiment preferably contains a first amine compound (b1-1) and a second amine compound (b1-2). The total content of the first amine compound (b1-1) and the second amine compound (b1-2) relative to the total curing agent (B) is preferably 5% to 90% by mass, more preferably 10% to 80% by mass, even more preferably 15% to 60% by mass, and even more preferably 20% to 40% by mass.

[0080] <<Amine Value>> In the curing agent (B) of this embodiment, the total amine value of the primary or secondary amine compound component (b1) is preferably 20 mg KOH / g to 500 mg KOH / g, more preferably 20 mg KOH / g to 400 mg KOH / g, and even more preferably 20 mg KOH / g to 300 mg KOH / g. Similarly, the total amine value of the curing agent (B) in this embodiment is preferably 100 mg KOH / g to 500 mg KOH / g, more preferably 150 mg KOH / g to 450 mg KOH / g, and even more preferably 200 mg KOH / g to 400 mg KOH / g. The amine values ​​of the above-mentioned amine compounds and the curing agent (B) of this embodiment are calculated by converting the measured amine values ​​(mgKOH / g) to solid content, as shown in the Examples section below, in accordance with the method of ASTM D2074.

[0081] <Alcohol content (b2)> The curing agent (B) of this embodiment contains an alcohol component (b2) as an essential component. The alcohol compound constituting the alcohol component (b2) is composed of a compound containing one or more hydroxyl groups, and contains one or more alcohols containing one or more hydroxyl groups and one or more cyclic groups. This makes it easier to suppress the reaction between moisture in the external atmosphere and the isocyanate groups, and the hydroxyl groups derived from the alcohol component (b2) in the curing agent (B) proceed with the urethane reaction, thus suppressing or preventing foaming and resulting in good curability at low temperatures. The mixing ratio ((b2) / (b1)) of the alcohol component (b2) and the primary or secondary amine compound component (b1) to the total curing agent (B) is preferably 50 / 100 to 500 / 100, more preferably 100 / 100 to 300 / 100, and even more preferably 100 / 100 to 200 / 100. The total hydroxyl value of the alcohol component (b2) is preferably 100 mg KOH / g or more and 1000 mg KOH / g or less, more preferably 200 mg KOH / g or more and 500 mg KOH / g or less, and even more preferably 200 mg KOH / g or more and 300 mg KOH / g or less. The total acid value of the alcohol component (b2) is preferably 0 mg KOH / g or more and 10 mg KOH / g or less, more preferably 0 mg KOH / g or more and 8 mg KOH / g or less, and even more preferably 0 mg KOH / g or more and 4 mg KOH / g or less. The methods for measuring the hydroxyl value and acid value shall be those described in the Examples section below.

[0082] The alcohol component (b2) of this embodiment essentially contains the polyhydric alcohol compound (b2-1) described later, and may further contain the alcohol compound (b2-2) as needed.

[0083] <<Polyhydric alcohol compound (b2-1)>> The polyhydric alcohol compound (b2-1) in this embodiment is a compound having a cyclic hydrocarbon group and containing two or more hydroxyl groups, with a hydroxyl value of 10 mg KOH / g or more and 1,500 mg KOH / g or less. Therefore, by selecting materials with a low hydroxyl value, water absorption is suppressed, which is thought to be the reason for the foam-inhibiting effect. Considering the reaction with the isocyanate compound (a1) coexisting in the main component (A), the polyhydric alcohol compound (b2-1) is preferably a compound with a weight-average molecular weight (Mw) of 200 to 2000, and more preferably 500 to 1000. The average number of functional groups (average number of hydroxyl groups) of the polyhydric alcohol compound (b2-1) in this embodiment may be 2 to 10 per molecule, preferably 2 to 6, more preferably 2 to 4, even more preferably 2 to 3, and particularly preferably 2 to 2.5. The hydroxyl value of the polyhydric alcohol compound (b2-1) in this embodiment is, for example, preferably 15 mg KOH / g or more and 800 mg KOH / g or less, more preferably 16 mg KOH / g or more and 500 mg KOH / g or less, and even more preferably 20 mg KOH / g or more and 100 mg KOH / g or less. Furthermore, the weight-average molecular weight (Mw) of the preferred polyhydric alcohol compound (b2-1) in this embodiment is preferably 500 to 10000, more preferably 800 to 7000, and even more preferably 1000 to 5000.

[0084] The polyhydric alcohol compound (b2-1) of this embodiment preferably has a hydrophobic chemical structure (for example, a long-chain hydrocarbon group, an aromatic ring, or other cyclic group) from the viewpoint of suppressing foaming. If the polyhydric alcohol compound (b2-1), which is the main component of the curing agent (B), has a hydrophobic chemical structure (for example, a long-chain hydrocarbon group, an aromatic ring, or other cyclic group), then not only the curing agent (B) but also the coating film obtained by contacting it with the main agent (A) tends to be hydrophobic. This makes it difficult for the coating to absorb moisture from the atmosphere, and thus it is thought that the occurrence of foaming can be suppressed. The polyhydric alcohol compound (b2-1) in this embodiment has a cyclic hydrocarbon group, and therefore is considered to have high hydrophobicity, which can further suppress or prevent foaming. The cyclic hydrocarbon group is preferably an aromatic hydrocarbon group, and it is preferable that it has at least one ring structure selected from the group consisting of bisphenol A, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, and bisphenol Z.

[0085] In this embodiment, a vegetable oil-modified polyol is preferred as the polyhydric alcohol compound (b2-1). The vegetable oil-modified polyol has an average number of functional groups (average number of hydroxyl groups) of 2 or more and is a polyol synthesized using vegetable oil as a starting material. Examples of the vegetable oil include coconut oil, soybean oil, corn oil, olive oil, castor oil, tall oil, cottonseed oil, camellia oil, linseed oil, tung oil, palm oil, safflower oil, and fatty acids contained in these oils. In this embodiment, a castor oil-modified polyol is preferred as the polyhydric alcohol compound (b2-1) from the viewpoint of exhibiting high hydrophobicity. Furthermore, since castor oil is a fatty oil mainly composed of ricinoleic acid glycerides, the castor oil-modified polyol may be, for example, a ricinoleic acid-modified polyol. When the polyhydric alcohol compound (b2-1) in this embodiment is a castor oil-modified polyol, it tends to exhibit foam suppression and high hardness effects.

[0086] Examples of castor oil-modified polyols in this embodiment include, for example, alkylene oxide adducts of castor oil, esterified compounds of castor oil or castor oil-derived fatty acids and polyol compounds, polyols obtained by adding epoxy group-containing bisphenol compounds (obtained by reacting the hydroxyl group of a bisphenol compound described later with epichlorohydrin, etc.) to castor oil or castor oil-derived fatty acids (e.g., ricinoleic acid), partially dehydrated or partially acylated diol-type castor oil, or hydrogenated versions thereof, or compounds having these chemical structures. Furthermore, the castor oil-modified polyol may have one or more ester bonds in its molecule.

[0087] Examples of the castor oil-modified polyol include products obtained by a transesterification reaction between castor oil or hydrogenated castor oil and a polyol compound. The castor oil-modified polyol may also be, for example, a product obtained by an esterification reaction between ricinoleic acid or 12-hydroxystearic acid and a polyol compound. In this specification, "hydrogenated castor oil" refers to castor oil in which some or all of the carbon-carbon unsaturated double bonds have been hydrogenated. Furthermore, the polyol compound may contain only one compound as a castor oil-modified polyol, or it may contain two or more compounds.

[0088] Examples of polyols used in the transesterification or esterification reaction include 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, trimethylhexanediol, neopentyl glycol, tripropylene glycol, 1,4-cyclohexanedimethanol, and bisphenol compounds. The bisphenol compound is preferably at least one selected from the group consisting of bisphenol A, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, and bisphenol Z.

[0089] In this embodiment, the castor oil-modified polyol is preferably having an aromatic ring, and more preferably having a cyclic group derived from the bisphenol compound, from the viewpoint of suppressing foaming. Examples of the castor oil-modified polyol include the epoxy group-containing bisphenol compound (an epoxidized product having the bisphenol A or bisphenol F skeleton) to which castor oil or a fatty acid derived from castor oil (for example, ricinoleic acid) is added. If the polyhydric alcohol compound (b2-1), which is the main component of the curing agent (B), has a highly hydrophobic chemical structure, then not only the curing agent (B) but also the coating film obtained by contacting it with the main agent (A) tends to exhibit hydrophobicity. This makes it less likely for the coating to absorb moisture from the atmosphere, thus further suppressing the occurrence of foaming.

[0090] <<Alcohol compound (b2-2)>> The alcohol component (b2) of this embodiment may include a polyhydric alcohol compound (b2-1) and an alcohol compound (b2-2). The content of the alcohol compound (b2-2) relative to the total curing agent (B) is preferably 0% to 40% by mass, more preferably 0% to 30% by mass, even more preferably 0% to 20% by mass, and even more preferably 0% to 10% by mass, or greater than 0% by mass and less than or equal to 10% by mass.

[0091] The preferred alcohol compound (b2-2) in this embodiment is not particularly limited as long as it is a compound containing two or more hydroxyl groups, but if effervescence is important, an aromatic ring-containing polyhydric alcohol compound (b2-2.1) is preferred. The average number of functional groups (average number of hydroxyl groups) of the second polyhydric alcohol compound in this embodiment may be 2 to 12, preferably 2 to 10, more preferably 2 to 8, even more preferably 2 to 6, and particularly preferably 2 to 5 per molecule. By using the alcohol compound (b2-2) of this embodiment, it is possible to adjust the blending ratio and improve the effect of suppressing foaming. Furthermore, the number-average molecular weight of the preferred alcohol compound (b2-2) in this embodiment is preferably 300 to 12000, more preferably 500 to 9000, and even more preferably 600 to 5000. The hydroxyl value of the alcohol compound (b2-2) in this embodiment is, for example, preferably 200 mg KOH / g or more and 1,000 mg KOH / g or less, more preferably 250 mg KOH / g or more and 900 mg KOH / g or less, and even more preferably 300 mg KOH / g or more and 900 mg KOH / g or less. Specific examples of the alcohol compound (b2-2) in this embodiment are preferably one or more compounds selected from the group consisting of polypropylene glycol, polyethylene glycol, polyether polyols, polytetramethylene ether glycols, polycaprolactone polyol, polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, polyolefin polyols, aniline polyol, hydrogenated polyisoprene polyol, low molecular weight polyols, polycarbonate polyol, castor oil, pentaerythritol-based polyether polyol, polymer polyol, and flame-retardant polyols containing phosphorus, etc. Examples of the aforementioned polyether polyols include polyether polyol compounds reacted with one or more selected from the group consisting of bisphenol A, glycerin, trimethylolpropane, ethylenediamine, pentaerythritol, triethanolamine, monoethanolamine, methyl glycoside, sorbitol, sorbitolamine, diethylenetriamine, sucrose, sucroseamine, toluenediamine, aminoethylpiperazine, aniline, and metaxylenediamine, along with an alkylene oxide (e.g., propylene oxide or ethylene oxide). This reaction is mainly carried out by addition polymerization. Examples of the aforementioned polyolefin-based polyols include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,3-propanediol, and 1,9-nonanediol. Examples of the aniline-based polyols include 2-anilinodiethanol, anilinodi-2-propanol, and m-anilinophenol. Examples of the low molecular weight polyols include neopentyl glycol, methylpentanediol, diethylene glycol, and propylene glycol. The aforementioned polytetramethylene ether glycols (PTMGs) can be obtained by ring-opening polymerization of tetrahydrofuran (THF). The alcohol compound (b2-2) of this embodiment may be used alone or as a mixture of two or more. As the aromatic ring-containing polyhydric alcohol compound (b2-2.1) having the aforementioned aromatic ring, an aniline-based polyol (for example, N,N-bis(2-hydroxypropyl)aniline) is preferred.

[0092] The curing agent (B) of this embodiment may consist substantially only of a primary or secondary amine compound component (b1), an alcohol component (b2), and any additives described below. In this specification, "consisting substantially only of a primary or secondary amine compound component (b1), an alcohol component (b2), and any additives described below" means that 90% to 100% by mass, preferably 95% to 100% by mass, and more preferably 98% to 100% by mass of the curing agent (B) is comprised of the total content of the primary or secondary amine compound component (b1), the alcohol component (b2), and any additives described below. In another embodiment, the curing agent (B) of this embodiment may consist substantially only of a primary or secondary amine compound component (b1) and an alcohol component (b2).

[0093] "Additives" The main component (A) and / or curing agent (B) of this embodiment may contain any additives as needed. Examples of such additives include one or more components selected from the group consisting of imine compounds, urethane-treated amine catalysts, urethane-treated metal catalysts, antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, plasticizers, inorganic fillers, defoamers, dehydrators, colorants, and dispersants. The total amount of additives in the main component (A) may be preferably 0% to 15% by mass, and preferably 0% to 11% by mass, relative to the total amount of the main component (A). The total content of additives in the curing agent (B) may be preferably 0% to 30% by mass, more preferably 0% to 16% by mass, and even more preferably 0% to 12% by mass, relative to the total amount of curing agent (B).

[0094] As the above-mentioned antioxidant, known antioxidants can be used. Examples of such antioxidants include one or more selected from the group consisting of phenolic compounds, phosphorus compounds, and thioether compounds. The antioxidant is preferably included in the curing agent (B).

[0095] Examples of the above-mentioned phenolic antioxidants include 2,6-diphenyl-4-octadecyloxyphenol, distearyl(3,5-di-tert-butyl-4-hydroxybenzyl)phosphonate, 1,6-hexamethylenebis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 2,6-di-tert-butyl-p-cresol, 4,4'-thiobis(6-tert-butyl-m-cresol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and 2,2'-methylene Bis(4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-m-cresol), 2,2'-ethylidenebis(4,6-di-tert-butylphenol), 2,2'-ethylidenebis(4-sec-butyl-6-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl)isocyanurate, 1,3,5-tris(3 ,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 2-tert-butyl-4-methyl-6-(2-acryloyloxy-3-tert-butyl-5-methylbenzyl)phenol, stearyl [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate methyl ]methane, thiodiethylene glycol bis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,6-hexamethylene bis[(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], bis[3,3-bis(4-hydroxy-3-tert-butylphenyl)butyric acid] glycol ester, bis[2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl] terephthalate, 1,3,5-tris[(3,Examples include 5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl isocyanurate, 3,9-bis[1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, and triethylene glycol bis[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate]. These phenolic antioxidants may be used individually or in combination of two or more.

[0096] Examples of the phosphorus-based antioxidants mentioned above include tris(2,4-di-tert-butylphenyl) phosphite, trisnonylphenyl phosphite, tris[2-tert-butyl-4-(3-tert-butyl-4-hydroxy-5-methylphenylthio)-5-methylphenyl] phosphite, tridecyl phosphite, octyldiphenyl phosphite, di(decyl)monophenyl phosphite, di(tridecyl)pentaerythritol diphosphite, and di(nonylphenyl)pentaerythritol. Tall diphosphite, bis(2,4-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,4,6-tri-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, tetra(tridecyl)isopropylidene diphenol diphosphite, tetra(tridecyl)-4,4'-n- Chilidenbis(2-tert-butyl-5-methylphenol) diphosphite, hexa(tridecyl)-1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane triphosphite, tetrakis(2,4-di-tert-butylphenyl) biphenylenediphosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis(4,6-tert-butylphenyl)-2-ethylhexylphosphite Examples include 2,2'-methylenebis(4,6-tert-butylphenyl)-octadecyl phosphite, 2,2'-ethylidenebis(4,6-di-tert-butylphenyl)fluorophosphite, tris(2-[(2,4,8,10-tetrakis-tert-butyldibenzo[d,f][1,3,2]dioxaphosphine-6-yl)oxy]ethyl)amine, and phosphites of 2-ethyl-2-butylpropylene glycol and 2,4,6-tri-tert-butylphenol. These phosphorus-based antioxidants may be used individually or in combination of two or more.

[0097] Examples of the thioether-based antioxidants mentioned above include dialkylthiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, as well as pentaerythritol tetra(β-alkylmercaptopropionate esters). These thioether-based antioxidants may be used individually or in combination of two or more.

[0098] The above-mentioned UV absorber can be any known UV absorber. Specific examples of such UV absorbers include benzophenone compounds, benzotriazole compounds, salicylate compounds, substituted acrylonitrile compounds, and metal chelate compounds. Benzotriazole-based UV absorbers are particularly preferred, including Tinuvin P, Tinuvin 213, Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 328, Tinuvin 329, and Tinuvin 571 (all manufactured by BASF). These UV absorbers may be used individually or in combination of two or more. The UV absorber is preferably included in the curing agent (B).

[0099] The above-mentioned light stabilizer is not particularly limited, and known light stabilizers can be used. Specific examples of such light stabilizers include benzotriazole compounds, hindered amine compounds, benzoate compounds, etc. These light stabilizers may be used individually or in combination of two or more. The light stabilizer is preferably included in the curing agent (B).

[0100] The above flame retardants are not particularly limited, and known flame retardants can be used. Specific examples of such flame retardants include: red phosphorus; phosphate esters such as triphenyl phosphate, cresyldiphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris(t-butylated phenyl) phosphate, or tris(i-propylated phenyl) phosphate; phosphate-containing flame retardants such as ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, magnesium hydrogen phosphate, or trimagnesium phosphate; bromine-containing flame retardants such as tetrabromobisphenol A (TBBA), TBBA-epoxy oligomer, TBBA-polycarbonate oligomer, or TBBA-bis(dibromopropyl ether); borax, diboron trioxide. Examples of flame retardants include boron-containing flame retardants such as boron trioxide, boron dioxide, tetraboron trioxide, boric acid, lithium borate, sodium borate, or potassium borate; antimony-containing flame retardants such as antimony trioxide, antimony pentoxide, or sodium antimonate; metal hydroxides such as aluminum hydroxide or magnesium hydroxide; and compounds having a cyclic structure including a heterocyclic or aromatic ring and a functional group including an ethylenically or acetylenely unsaturated carbon bond (e.g., triallyl isocyanurate (TAIC), trimetile isocyanurate (TMAIC), triallyl cyanurate (TAC), or ethoxylated isocyanurate triacrylate (TEAIC)). These flame retardants may be used individually or in combination of two or more. The flame retardants are preferably included in the curing agent (B).

[0101] The plasticizer described above is not particularly limited, and any known plasticizer can be used. Specific examples of such plasticizers include dicarboxylic acid ester compounds, and more preferably sebacate ester compounds, phthalate ester compounds, adipic ester compounds, aliphatic dibasic acid ester compounds, glycol ester compounds, phosphate ester compounds, and epoxy compounds. Examples of the sebacate ester compounds include dimethyl sebacate, diethyl sebacate, dipropyl sebacate, di-n-butyl sebacate, dipentyl sebacate, dihexyl sebacate, diheptyl sebacate, dioctyl sebacate, di-2-ethylhexyl sebacate, diisodecyl sebacate, and diisononyl sebacate. When the curing agent (B) contains the above-mentioned sebacate ester compound, it tends to become less viscous and its reactivity with the main component (A) improves. Examples of the phthalate ester compounds include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, diisooctyl phthalate, di-2-ethylhexyl phthalate, dinonyl phthalate, diisodecyl phthalate, ditridecyl phthalate, dibutylpentyl phthalate, and dicyclohexyl phthalate. Examples of the adipate ester compounds include dimethyl adipate, diethyl adipate, dibutyl adipate, diheptyl adipate, diisononyl adipate, di-n-octyl adipate, diisooctyl adipate, di-2-ethylhexyl adipate, dinonyl adipate, diisononyl adipate, diisodecyl adipate, ditridecyl adipate, dibutylpentyl adipate, and dicyclohexyl adipate. Furthermore, examples of the aliphatic dibasic acid ester compounds include citrate esters, acetyl citrate esters, trimellitic acid esters, oleic acid esters, palmitic acid esters, and stearic acid esters. These plasticizers may be used individually or in combination of two or more. The plasticizers are preferably included in the curing agent (B).

[0102] The inorganic filler described above is not particularly limited, and known inorganic fillers can be used. Specific examples of such inorganic fillers include silicas such as fused silica, crystalline silica, and cristobalite, alumina, silicon nitride, aluminum nitride, boron nitride, titanium oxide, glass fiber, and magnesium oxide. These inorganic fillers may be used individually or in combination of two or more. The average particle size and shape of the inorganic filler can be selected according to the application. The inorganic filler is preferably included in the curing agent (B).

[0103] The above-mentioned defoaming agent is not particularly limited, and any known defoaming agent can be used. Specific examples of such defoaming agents include silicone-based defoaming agents such as dimethylpolysiloxane, polyoxyalkylene alkyl ethers, synthetic resin particles, and untreated silica. These defoaming agents may be used individually or in combination of two or more. The defoaming agent is preferably included in the curing agent (B).

[0104] The above-mentioned colorants are not particularly limited, and known colorants can be used. Specific examples of colorants for the defoaming agent include carbon black, chrome yellow, Hansa yellow, benzidine yellow, surene yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, balkan orange, Watch Young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, risole red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, and others. Examples include various pigments such as ultramarine blue, chalcioyl blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate; and various dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole. These colorants may be used individually or in combination of two or more. The colorants are preferably included in the curing agent (B).

[0105] The above-mentioned dehydrating agent is not particularly limited, and any known dehydrating agent can be used. Specific examples of such dehydrating agents include synthetic zeolite, activated alumina (Al2O3), silica gel (SiO2), quicklime, and magnesium oxide. These dehydrating agents may be used individually or in combination of two or more. The dehydrating agent is preferably included in the curing agent (B).

[0106] The above-mentioned dispersant is not particularly limited, and any known dispersant can be used. Specific examples of such dispersants include BYK-W961, BYK-W935 (manufactured by Bic Chemie Japan Co., Ltd.), and Polyflow No. 77 (manufactured by Kyoeisha Chemical Co., Ltd.). The dispersant is preferably included in the curing agent (B).

[0107] In particular, the curing agent (B) of this embodiment preferably contains one or more selected from the group consisting of plasticizers, imine compounds, urethane-treated amine catalysts, and urethane-treated metal catalysts. The curing agent (B) of this embodiment may optionally contain an imine compound containing a tertiary amine. The imine compound is not particularly limited as long as it has a tertiary amine (-N=) in its molecule, but compounds with a molecular weight of 50 to 300 are preferred. The imine compound containing the tertiary amine is preferably an imidazole. By using the imine compound containing the tertiary amine, the post-curing process can be accelerated. The molecular weight of the imine compound is preferably 50 to 300, more preferably 60 to 250, and even more preferably 70 to 200. 1-methylimidazole is particularly preferred as the imine compound. When the curing agent (B) contains an imine compound, it tends to exhibit a curing-accelerating function.

[0108] The curing agent (B) of this embodiment may optionally contain a urethane-forming amine catalyst such as a quaternary ammonium salt. When the curing agent (B) contains a urethane-forming amine catalyst such as a quaternary ammonium salt, the content of the urethane-forming amine catalyst such as the quaternary ammonium salt is preferably greater than 0% by mass and 8% by mass or less, relative to the total curing agent (B) (100% by mass). Specific examples of the quaternary ammonium salt include tetramethylammonium cation, methyltriethylammonium cation, tetraethylammonium cation, tributylmethylammonium cation, tetrabutylammonium cation, phenyltrimethylammonium cation, benzyltrimethylammonium cation, phenyltriethylammonium cation, benzyltriethylammonium cation, chloride salts of benzyltributylammonium cation; and bromide salts of tetramethylammonium cation, trimethylpropylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, etc. These compounds may be used individually or in combination of two or more.

[0109] The curing agent (B) of this embodiment may, if necessary, contain a known urethane metal catalyst such as an organotin compound, an organolead compound, or an organobismuth compound instead of the quaternary ammonium salt, or in combination with the quaternary ammonium salt. When the curing agent (B) contains the urethane metal catalyst, the content of the urethane metal catalyst is preferably more than 0% by mass and 8% by mass or less, relative to the total curing agent (B) (100% by mass). Examples of the organotin compounds include stanus diacetate, stanus dioctoate, stanus dioleate, stanus dilaurate, dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin oxide, and dibutyltin dichloride. Examples of the aforementioned organic lead compounds include lead octanoate and lead naphthenate. Examples of the aforementioned organic bismuth compounds include bismuth octylate, bismuth neodecanoate, and bismuth naphthenate. These compounds may be used individually or in combination of two or more.

[0110] [Use of a two-component curing composition for coating the inner walls of water pipes] The two-component curing composition for coating the inner walls of water pipes in this embodiment is a resin composition in a two-component kit comprising a main component (A) and a curing agent (B) prepared separately. The main component (A) essentially contains an isocyanate compound (a1), and the curing agent (B) essentially contains a primary or secondary amine compound component (b1) and a polyhydric alcohol compound (b2-1). Therefore, when the main component (A) and the curing agent (B) are brought into contact, a polyurethane urea resin cured product can be formed. The main component (A) and the curing agent (B) are compounded (mixed) at the time of use and cured to produce a cured product. In other words, in the above-mentioned two-component curing composition for coating the inner walls of water pipes, when liquid (A) and liquid (B) come into contact, urethane and urea reactions proceed simultaneously between the isocyanate group in the isocyanate compound (a1) in the main agent (A) and the hydroxyl group in the polyhydric alcohol compound (b2-1) in the curing agent (B) and the so-called active hydrogen groups derived from the amino groups of each amine compound. As a result, the reaction between moisture in the external atmosphere and the isocyanate group is suppressed, and a cured product is obtained, which is thought to suppress or prevent the occurrence of foaming and to have good curability at low temperatures. In the two-component curing composition for coating the inner wall of a water pipe according to this embodiment, when the main agent (A) (also simply referred to as (A) liquid) and the curing agent (B) (also simply referred to as (B) liquid) are brought into contact to coat the inner wall of a water pipe with a cured product, the mixing ratio (mass ratio) (main agent (A) / curing agent (B)) of the main agent (A) and the curing agent (B) can preferably be in the range of 80 / 20 to 20 / 80, more preferably in the range of 70 / 30 to 30 / 70, and even more preferably in the range of 60 / 40 to 40 / 60.

[0111] (Curing conditions for two-component curing type compositions for coating the inner walls of water pipes) The curing temperature between the main component (A) and the hardener (B) is, for example, 0°C to 50°C, more preferably 10°C to 30°C. The curing time in the curing reaction between the main component (A) and the hardener (B) is, for example, 10 minutes to 120 minutes, more preferably 10 minutes to 60 minutes. This curing time refers to the time from when the main component (A) and the hardener (B) come into contact until the Shore A hardness reaches 50 or higher. As a result, the main agent (A) and the hardening agent (B) come into contact and harden, forming a coating that covers the inner wall of the water pipe, thereby coating the inner wall of the water pipe.

[0112] "Method for using a two-component curing composition for coating the inner walls of water pipes" The method for coating the inner wall of a water pipe with the two-component curable composition of this embodiment onto the inner wall of a water pipe and curing it is not particularly limited, and known apparatus and methods can be used. Specifically, the method for coating the inner wall of a water pipe with the two-component curable composition of this embodiment onto the inner wall of a water pipe and curing it comprises the steps of mixing the main agent (A) and the curing agent (B), a cleaning step if necessary, applying the mixture of the main agent (A) and the curing agent (B) to the inner wall of the water pipe, and a drying step if necessary. Alternatively, the mixing step and the application step may be the same step, that is, the mixture of the main agent (A) and the curing agent (B) may be mixed while applying it to the inner wall of the water pipe. Or, the main agent (A) and the curing agent (B) may be mixed to prepare a mixture, and then the mixture may be applied to the inner wall of the water pipe.

[0113] An example of applying and curing a two-component curing composition for coating the inner walls of water pipes is described below. <Mixing process> The mixing process may involve weighing the main component (A) and the hardener (B) separately using a scale, then adding them to the same container in a mixing ratio (main component (A) / hardener (B) (mass ratio)) of 80 / 20 to 20 / 80, and mixing them with a stirrer (for example, an electric stirrer) to prepare a mixture of the main component (A) and the hardener (B).

[0114] Another aspect of the mixing process involves using a pumping means such as a gear pump or a plunger pump to pump the main component (A) and the hardener (B) into two hoses at a mixing ratio (main component (A) / hardener (B) (mass ratio)) of 80 / 20 to 20 / 80, and connecting a static mixer or similar device to the end of each of the two hoses to mix the main component (A) and the hardener (B) to prepare a mixed solution.

[0115] Furthermore, another aspect of the mixing process involves using a pumping means such as a gear pump or plunger pump to pump the main component (A) and the hardener (B) into two hoses at a mixing ratio (main component (A) / hardener (B) (mass ratio)) of 80 / 20 to 20 / 80, and using a two-component mixing injector nozzle connected to the end of each of the two hoses and an air hose connected to the two-component mixing injector nozzle, the main component (A), the hardener (B), and compressed air (for example, 0.1 MPa to 0.5 MPa) are sent into the two-component mixing injector nozzle and injected from the injector nozzle to mix by collision reaction.

[0116] <Cleaning Process> Next, if necessary, the inner surface of the water pipe to be coated with a two-component curing composition for coating the inner wall of the water pipe may be cleaned to prepare the surface. Specifically, this cleaning process involves connecting a known suction device to the lower side of the water pipe to be coated and operating it to circulate air at high speed inside the water pipe, thereby introducing an abrasive material (e.g., natural stone, silica sand, ceramic powder) from the upper side of the water pipe. As a result, the abrasive material flows from the upper side to the lower side of the water pipe due to the high-speed airflow (e.g., wind speed of 20-40 ms) generated by the suction force of the suction device, thus polishing the inner surface of the water pipe. The removed deposits, rust, iron powder, or abrasive material can be collected in the suction device. Furthermore, any fine impurities remaining inside the water pipe after polishing may be washed away by flushing water from the upper side and suctioning it from the lower side. After that, if necessary, the inside of the water pipe may be dried by suction or natural drying. Furthermore, the cleaning process is not limited to the polishing method described above, and may also employ pressurized methods such as polishing a rotary polishing jig, polishing a rotary chain, or high-pressure cleaning.

[0117] <Application process> If necessary, after confirming that the inside of the water pipe to be coated is dry, a mixture of the main agent (A) and the hardener (B) is applied. The mixture, which has been mixed by hand, with a gear pump, or with a static mixer, is then introduced from the top of the water pipe from the same cleaning process as described above, after generating a high-speed airflow (wind speed 20-40 ms) inside the water pipe from the bottom using a known suction device, or while generating the airflow. As a result, the introduced mixture is uniformly dispersed and spread inside the water pipe according to the principle of annular two-layer flow. As a result, a smooth coating film is formed on the entire inner surface of the water pipe. In addition, after introducing the paint, a jig or auxiliary tool may be passed through the water pipe to adjust the coating film thickness inside the water pipe. Alternatively, a known two-component mixing injector nozzle may be connected to a known air hose, compressed air (e.g., 0.1 MPa to 0.5 MPa) may be supplied by a compressor, and the main component (A), hardener (B), or mixture may be sprayed from the tip of the two-component mixing injector nozzle while being pulled up at a constant speed from the bottom to the top of the water pipe. If necessary, after the spray coating, an airflow may be circulated through the water pipe using a suction device to ensure uniformity of the coating surface and adjust the coating thickness.

[0118] <Drying process> After the coating has formed over the entire inside of the water pipe, it may be allowed to air dry naturally, or if necessary, warm air may be blown into the water pipe to speed up the drying time. The time required for complete curing depends on the weather, the solid content concentration in the main component (A) and the hardener (B), etc., but for example, it takes about 8 hours at 33°C, for example, 4 hours at 25°C, and 1.5 hours at 40°C. The coating film thickness is usually preferably about 0.3 mm to 5 mm. This allows the two-component curing composition for coating the inner walls of water pipes to harden, and a cured product (e.g., a film) to be obtained. Since such a cured product is formed from the above-mentioned two-component curing composition for coating the inner walls of water pipes, it exhibits excellent hardening and conformability within the water pipe, and after hardening, it exhibits excellent chemical resistance and heat resistance.

[0119] This disclosure relates to a water pipe with an inner wall coating, comprising a water pipe body and a cured product of a two-component curable composition for coating the inner wall of the water pipe according to this embodiment, which is applied to the inner wall of the water pipe body. As described above, it was confirmed that a water pipe with an inner wall coating, obtained by applying and curing the two-component curable composition for coating the inner wall of a water pipe according to this embodiment, exhibits significantly improved impact resistance and mechanical strength, such as elongation, compared to a water pipe body that is not coated with the cured two-component curable composition for coating the inner wall of a water pipe according to this embodiment. Furthermore, even if the shape of the water pipe body is curved, the two-component curing composition for coating the inner wall of the water pipe in this embodiment has an appropriate viscosity, so it can coat the inner wall of the water pipe body with the cured material in accordance with the shape of the water pipe body, thus demonstrating excellent conformability. [Examples]

[0120] The present disclosure will be described below using examples and comparative examples as illustrations, but the scope of the present disclosure is not limited to the examples described below.

[0121] 1. Evaluation Method (1) Measurement of curing time The following two-component curing compositions were used in the examples and comparative examples. A mixture of each main component and each curing agent was applied to a stainless steel plate to a film thickness of 3 mm. The hardness was then measured under various temperature atmospheres, and the time until the Shore A hardness reached 50 or higher was defined as the curing time. Hardness (A) is based on JIS K7215 (Durometer hardness test method for plastics). The hardness (A) (=Shore A hardness) was measured in accordance with the standard.

[0122] (2) Evaluation of foaming properties The following two-component curing compositions, each containing a main component and a curing agent, were mixed and applied to a stainless steel plate to a thickness of approximately 2 mm. The mixture was then left to stand for 16 hours at a temperature of 35°C and a humidity of 90%. The cured coating was then visually inspected from a distance of 30 cm and evaluated according to the following criteria. <Evaluation criteria for foaming> If no foaming was observed in the coating film, the foaming properties were evaluated as good and indicated as "Excellent" in Table 2. If the number of foamed areas in the coating film was less than 10, the foaming properties were evaluated as usable, and "Acceptable" was indicated in Table 2. If foaming occurred in the coating film, the foaming property was evaluated as unacceptable and indicated as "Unacceptable" in Table 2.

[0123] (3) Measurement of hardness and elongation 100g of each main component prepared in the examples and comparative examples was weighed into a stirring container, and then 100g of each curing agent prepared in the examples and comparative examples was added, and the mixture was stirred and mixed in a vacuum casting machine for 1 minute to obtain a mixture. Next, the mixture was poured into a mold coated with Teflon® to produce 3mm thick sheets. Next, each sheet was left to stand at 60°C for 1 hour, then demolded, left to stand at 60°C for 24 hours, and then left to stand at room temperature (25°C) for 24 hours to produce test pieces that were cured products from the two-component curing type composition for coating the inner walls of water pipes in the examples and the composition of the comparative examples, respectively. The obtained test specimens were then subjected to Shore D hardness testing using a durometer-hardness tester (Type D) in accordance with ISO-868. Additionally, the elongation at break (%) was measured in accordance with JIS A 6021 (2011). The results are shown in Table 2 below.

[0124] (4) Evaluation of chemical resistance <Method for preparing test specimens> After preparing a stainless steel substrate, a mixture of the main component and curing agent of the two-component curing compositions of Examples 1-3 and Comparative Example 4 was applied to the substrate to a coating thickness of 3 mm. Then, the sample was cut to a size of 30 mm x 30 mm to prepare each test specimen. <Evaluation Method> After preparing test specimens using the method described above, the initial mass of each specimen was measured before the chemical resistance evaluation. Then, the initial mass of each specimen after the chemical resistance evaluation was measured using the method described below, and the weight change rate (%) was calculated. In addition, the appearance of the coating was visually inspected to confirm the color, gloss, and presence or absence of peeling of the coating. The chemical resistance evaluation method is as follows. First, various solutions (distilled water, hydrochloric acid, sodium hydroxide aqueous solution, acetic acid aqueous solution, lactic acid aqueous solution) shown in Table 3 were prepared. Then, each test specimen was immersed in a container filled with the above-mentioned solutions and the container was sealed. Next, the containers containing the test specimens immersed in the various solutions at 40°C were placed in a constant temperature device maintained at an ambient temperature of 40°C, and the ambient temperature of 40°C was maintained for 7 days. After 7 days, the test specimens were removed from the containers, and the weight change rate (%) was calculated using the following method, and the condition of the coating on the inner wall of the pipe was observed. The results are shown in Table 3. Weight change rate (%) = (Weight of the test specimen before immersion in the various solutions - Weight of the test specimen after immersion in the various solutions for 7 days) / Weight of the test specimen before immersion in the various solutions The initial hardness (D) (=Shore D hardness) of the test specimens obtained from the compositions of Examples 1 to 3 was 81 to 85. Furthermore, it was confirmed that even after immersing the test specimens obtained from the compositions of Examples 1 to 3 in the various solutions described above for 7 days, all test specimens maintained a hardness (D) (=Shore D hardness) of 75 or higher. The hardness (D) of the test specimens obtained from the compositions of Examples 1 to 3 was measured using the method described in the section "(3) Measurement of Hardness and Elongation" above.

[0125] (5) Measurement of viscosity In accordance with JIS K 7117-1:1999, the viscosity of each main component and each curing agent prepared in the examples and comparative examples was measured after 2 minutes using a TV-100 viscometer at a measurement temperature of 25°C.

[0126] (6) Measurement of amine value and hydroxyl value If catalog values ​​or similar information are unavailable, the amine value of the primary or secondary amine compound component (b1) and the hydroxyl value of the polyhydric alcohol compound (b2-1) used in the examples and comparative examples shall be measured by the following method. The amine value (mgKOH / g) is determined by measuring the amount of potassium hydroxide equivalent to hydrochloric acid required to neutralize the amine-containing compound in 1 g of sample, according to the method specified in ASTM D2074. The hydroxyl value (mgKOH / g) was measured in accordance with the methods described in JIS K 0070-1992 and JIS K 1557-1.

[0127] (7) Measurement of structural analysis The chemical structure of the polyhydric alcohol compound (b2-1) was confirmed using analytical instruments (Winspec-50 FT-IR and diamond ATR instruments manufactured by JEOL). As a result, it was confirmed that both castor oil-modified polyols (1) and (2) used in the examples have a bisphenol A skeleton. On the other hand, it was confirmed that neither the castor oil-modified polyol nor the polyhydric alcohol compound (b2-1) used in the comparative example have an aromatic ring. Figures 1 and 2 show the FT-IR charts of the measurement results.

[0128] 2. Preparation of a two-component curing composition for coating the inner walls of water pipes (Example 1) <Preparation Example 1: Preparation of Main Ingredient (A1)> 80 parts by mass of polymeric MDI (polymethylene polyphenyl polyisocyanate: 4,4'-MDI = 55:45 (mass ratio)) and 20 parts by mass of monomeric MDI (2,4'-MDI: 4,4'-MDI = 55:45 (mass ratio)) were placed in a flask and mixed under a nitrogen atmosphere at 40°C for 0.5 hours to prepare main component (A1) (see composition in Table 1). The viscosity of main component (A1) at 25°C was 90 mPa·s.

[0129] <Preparation Example 2: Preparation of Hardener (B1)> As the alcohol component (b2), 60 parts by mass of castor oil-modified polyol (1) (manufactured by Ito Oil Co., Ltd., trade name: URIC F-40, average number of hydroxyl groups 3, hydroxyl value 236 mg KOH / g) and 6 parts by mass of N,N-bis(2-hydroxypropyl)aniline) were mixed in a flask to obtain a mixed solution (see composition in Table 1). In this case, the primary or secondary amine compound component (b1) contains 10 parts by mass of aspartic acid,N,N-(methylenedi-4,1-cyclohexanediyl)]bis,tetraethyl ester (desmophene NH1420, 2 functional groups, molecular weight 555, amine value 199 mgKOH / g) and 10 parts by mass of primary polyetherdiamine (2 functional groups, molecular weight 2000). Subsequently, the mixed solution was stirred in a stirrer under a nitrogen atmosphere at 80°C for 60 minutes to prepare the curing agent (B1). The viscosity of the curing agent (B1) at 25°C was 3,500 mPa·s.

[0130] Using the main component (A1) and hardener (B1) obtained in Preparation Example 1 and Preparation Example 2 above, a two-component curable composition (1) for coating the inner walls of water pipes was prepared. By stirring and mixing the main component (A1) and hardener (B1) at a mixing ratio (by weight) of 50:100, a cured product was prepared from the two-component curable composition (1) for coating the inner walls of water pipes, which contains the main component (A1) and hardener (B1).

[0131] (Example 2) <Preparation Example 3: Preparation of Main Ingredient (A2)> 80 parts by mass of polymeric MDI (polymethylene polyphenyl polyisocyanate: 4,4'-MDI = 55:45 (mass ratio)) and 20 parts by mass of monomeric MDI (2,4'-MDI: 4,4'-MDI = 55:45 (mass ratio)) were placed in a flask and mixed under a nitrogen atmosphere at 40°C for 0.5 hours to prepare the main component (A2). The viscosity of the main component (A2) at 25°C was 90 mPa·s.

[0132] <Preparation Example 4: Preparation of Hardener (B2)> As the alcohol component (b2), 60 parts by mass of castor oil-modified polyol (2) (manufactured by Ito Oil Co., Ltd., trade name: URIC F-97, average hydroxyl group count 3.0, hydroxyl value 335 mg KOH / g) and 6 parts by mass of N,N-bis(2-hydroxypropyl)aniline) were mixed in a flask to obtain a mixed solution (see composition in Table 1). In this case, the primary or secondary amine compound component (b1) contains 10 parts by mass of aspartic acid,N,N-(methylenedi-4,1-cyclohexanediyl)]bis,tetraethyl ester (desmophene NH1420, 2 functional groups, molecular weight 555, amine value 199 mgKOH / g) and 10 parts by mass of primary polyetherdiamine (2 functional groups, molecular weight 2000). Subsequently, the mixed solution was stirred in a stirrer under a nitrogen atmosphere at 80°C for 60 minutes to prepare the curing agent (B2). The viscosity of the curing agent (B2) at 25°C was 3,500 mPa·s.

[0133] Using the main component (A2) and hardener (B2) obtained in Preparation Example 3 and Preparation Example 4 above, a two-component curable composition (2) for coating the inner walls of water pipes was prepared. By stirring and mixing the main component (A2) and hardener (B2) at a mixing ratio (by weight) of 60:100, a cured product was prepared from the two-component curable composition (2) for coating the inner walls of water pipes, which contains the main component (A2) and hardener (B2).

[0134] (Example 3) <Preparation Example 5: Preparation of Main Ingredient (A3)> 80 parts by mass of polymeric MDI (polymethylene polyphenyl polyisocyanate: 4,4'-MDI = 55:45 (mass ratio)) and 20 parts by mass of monomeric MDI (2,4'-MDI: 4,4'-MDI = 55:45 (mass ratio)) were placed in a flask and mixed under a nitrogen atmosphere at 40°C for 0.5 hours to prepare the main component (A2). The viscosity of the main component (A2) at 25°C was 90 mPa·s.

[0135] <Preparation Example 6: Preparation of Hardener (B3)> As the alcohol component (b2), 60 parts by mass of castor oil-modified polyol (1) (manufactured by Ito Oil Co., Ltd., trade name: URIC F-40, average number of hydroxyl groups 3, hydroxyl value 236 mg KOH / g) and 5 parts by mass of N,N-bis(2-hydroxypropyl)aniline) were mixed in a flask to obtain a mixed solution (see composition in Table 1). In this case, the primary or secondary amine compound component (b1) contains 11 parts by mass of diethyl(2S)-2-[[5-[[(2S)-1,4-diethoxy-1,4-dioxobutan-2-yl]amino]-4-methylpentyl]amino]butanedioate (2 functional groups, molecular weight 475, amine value 236 mgKOH / g) and 10 parts by mass of primary polyetherdiamine (2 functional groups, molecular weight 2000). Subsequently, the mixed solution was stirred in a stirrer under a nitrogen atmosphere at 80°C for 30 minutes to prepare the curing agent (B3). The viscosity of the curing agent (B3) at 25°C was 3,300 mPa·s.

[0136] The main component (A3) and curing agent (B3) obtained in Preparation Example 5 and Preparation Example 6 above were prepared to obtain a two-component curable composition (3) for coating the inner walls of water pipes. A cured product was prepared from the two-component curable composition (3) for coating the inner walls of water pipes, which contains the main component (A3) and curing agent (B3), by stirring and mixing the main component (A3) and curing agent (B3) in a mixing ratio (by weight) of 50:100.

[0137] (Comparative Examples 1-3) Based on the composition ratios listed in Table 1, comparative two-component curable compositions (1) to (3) were prepared in the same manner as in Example 1. Then, comparative cured products (1) to (3) were prepared by stirring and mixing the main component and curing agent of the comparative two-component curable compositions (1) to (3) in a mixing ratio (by weight) of 50:100.

[0138] (Comparative Example 4) In Comparative Example 4, the following two-component epoxy resin composition was used. For comparison, a bisphenol A type epoxy resin (Nichibei Resin Co., Ltd., product name "Alpron L-HR") was used as the main component (a1). A modified aliphatic polyamine and isophorone diamine mixture (Nichibei Resin Co., Ltd., product name "Alpron L-HR") was used as a comparative curing agent (b1). A comparative two-component curing epoxy resin composition was obtained by preparing the above-mentioned comparative main component (a1) and comparative curing agent (b1). Furthermore, a cured product was prepared from a comparative two-component curing epoxy resin composition (4) for epoxy resin formation, comprising the comparative main component (a1) and the comparative curing agent (b1), by stirring and mixing the comparative main component (a1) and the comparative curing agent (b1) in a weight ratio of 5:1 (= main component (a1): curing agent (b1)).

[0139] [Table 1]

[0140] The compounds in Table 1 above are as follows: Castor oil-modified polyol (1) used was manufactured by Ito Oil Co., Ltd. (Yurik F-40). Castor oil-modified polyol (2) used was manufactured by Ito Oil Co., Ltd. (Yurik F-97). Polyaspartate ester (1) used was aspartic acid, N,N-(methylenedi-4,1-cyclohexanediyl)bis-tetraethyl ester. For polyaspartate ester (2), diethyl(2S)-2-[[5-[[(2S)-1,4-diethoxy-1,4-dioxobutan-2-yl]amino]-4-methylpentyl]amino]butanedioate was used.

[0141] [Table 2]

[0142] [Table 3]

[0143] 3. Evaluation of heat resistance A transparent polyvinyl chloride pipe (outer diameter 100 mm) with a channel length of 10 m and a bent shape was prepared (shape of pipe 1 shown in Figure 3). Next, the inside of the pipe was coated with a film using the airflow method (lining method) with the two-component curing composition for coating the inner wall of a water pipe prepared in Example 1. After that, it was left at 25°C for 2 hours and it was confirmed that a blue film had formed over the entire inside of the pipe with the bent section. Furthermore, the tube 1 having a bent section as shown in Figure 3 is a bent tube 1 with an inner wall coating process, in which the blue coating is formed on the inner wall of the transparent tube. Next, as shown in Figure 3, the inner-wall coated, bent-shaped pipe 1 was fixed so that the opening at one end of the pipe 1 faced directly upwards. Then, 2 liters of hot water (98°C) were poured from an electric kettle into the upward-facing opening, and the appearance of the blue coating was checked after waiting for the hot water to finish draining from the other end's opening. The procedure of "pouring 2 liters of boiling water (98°C) from an electric kettle into the upward-facing opening, waiting for the boiling water to finish draining from the other end, and then checking the appearance of the blue coating" was performed five times a day for a total of 20 days (100 times in total). Figure 4(a) shows the appearance of the hot water injection opening after the above operation was performed 50 times. Figure 4(b) shows the appearance of the hot water injection opening after the above operation was performed 100 times. As shown in Figures 4(a) and (b), no peeling or discoloration of the blue coating was observed at the hot water injection opening in either case. Furthermore, no abnormalities such as peeling or discoloration were observed in the coating of the entire pipe after performing the above operation 50 times, or in the coating of the entire pipe body 1 with the inner wall coated after performing the above operation 100 times.

[0144] Furthermore, using the two-component curing composition for coating the inner wall of water pipes prepared in Examples 2 and 3, and a bent, transparent polyvinyl chloride pipe (outer diameter 100 mm) with a flow path length of 10 m, the inside of the pipe was coated with a film using the airflow method (lining method), thereby producing bent pipes 1 with the inner wall coated. Next, by the method described in the column of the above “3. Method for Evaluating Heat Resistance to Hot Water”, 2 L of hot water (98°C) was poured from an electric kettle into the opening, and after waiting for the hot water to be completely discharged from the opening at the other end, the state of the blue coating was confirmed. This operation was performed 5 times a day for a total of 20 days (= 100 times in total). As a result, similarly when using the two-component curable composition for coating the inner wall of the water pipe prepared in Examples 2 to 3, no abnormalities such as peeling or discoloration were observed in either the coating of the entire pipe or the coating of the entire pipe after performing the operation 100 times. From the above, it was confirmed that the coating obtained from the two-component curable composition for coating the inner wall of the water pipe of the present disclosure exhibits excellent followability to the pipe body and shows heat resistance to hot water.

[0145] From the experimental results in Table 2 above, the two-component curable composition for coating the inner wall of the water pipe of this example shows excellent curability between the low temperature range (for example, -9°C) and the temperate zone (for example, around 40°C), and when the two-component curable composition for coating the inner wall of the water pipe is cured, it was confirmed that the generation of foaming is suppressed or prevented, and excellent elongation at break is shown while maintaining a predetermined hardness. From the experimental results in Table 3 above, it was confirmed that the two-component curable composition for coating the inner wall of the water pipe of this example forms a coating having high chemical resistance and high heat resistance to hot water. From the above, it was confirmed that the two-component curable composition for coating the inner wall of the water pipe of the present disclosure shows excellent curability between the low temperature range (for example, -8°C to -10°C) and the temperate zone (for example, around 45°C), and suppresses or prevents the generation of foaming during curing, and can form a coating having excellent elongation, high chemical resistance and high heat resistance to hot water while maintaining a predetermined hardness.

Industrial Applicability

[0146] This disclosure provides a two-component curing composition for coating the inner walls of water pipes that exhibits excellent curability in the low-temperature range (e.g., -8°C to -10°C) to the warm-temperature range (e.g., around 45°C), suppresses or prevents foaming during curing, and forms a film that maintains a predetermined hardness while possessing excellent elongation, high chemical resistance, and high heat resistance. This makes it possible to provide a simple means of repairing water pipes or to suppress the deterioration of water pipes over time. [Explanation of Symbols]

[0147] 1. A pipe body with an internally coated, bent section.

Claims

1. A two-component curing type composition for coating the inner wall of a water pipe, which hardens upon contact between a main component (A) and a hardening agent (B) to coat the inner wall of the water pipe, The main component (A) contains an isocyanate compound (a1), and the isocyanate compound (a1) contains an aromatic isocyanate compound represented by the following general formula (2): 【Chemistry 1】 (In the above general formula (2), R1, R2, and R3 each independently represent an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms; L1 and L2 each independently represent a single bond or an alkylene group having 1 to 3 carbon atoms; n1 and n2 each independently represent an integer from 0 to 4; n3 each independently represents an integer from 0 to 3; and m2 represents the degree of polymerization and is an integer from 0 to 3 or greater.) The curing agent (B) contains a primary or secondary amine compound component (b1) and an alcohol component (b2) containing a polyhydric alcohol compound (b2-1) having a cyclic hydrocarbon group and a hydroxyl value of 10 mg KOH / g or more and 800 mg KOH / g or less, and has a viscosity of 100 mPa·s or more and 10000 mPa·s or less at 25°C. The total content of the primary or secondary amine compound component (b1) relative to the entire curing agent (B) is 10% to 60% by mass, and the content of the polyhydric alcohol compound (b2-1) relative to the entire curing agent (B) is 10% to 80% by mass. The primary or secondary amine compound component (b1) is a first amine compound (b1-1) having an alkylene oxide group [-(CHR) nb-O-] mb (where R represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms) and at least two or more amino groups (-NH2), It comprises one or more second amine compounds (b1-2) selected from the group consisting of amino acid ester compounds or amino acid ester derivative compounds and cyclic amine compounds, The aforementioned polyhydric alcohol compound (b2-1) is a vegetable oil-modified polyol. A two-component curing composition for coating the inner walls of water pipes.

2. The curing agent (B) further contains a dicarboxylic acid ester compound as a plasticizer, the two-component curing composition for coating the inner wall of a water pipe according to claim 1.

3. The two-component curable composition for coating the inner wall of a water pipe according to claim 1 or 2, wherein the weight-average molecular weight (Mw) of the polyhydric alcohol compound (b2-1) is 100 to 2,000.

4. A two-component curing composition for coating the inner wall of a water pipe, according to claim 1 or 2, wherein the main component (A) and the curing agent (B) come into contact and harden to form a film that covers the inner wall of the water pipe, thereby coating the inner wall of the water pipe.

5. The alcohol component (b2) comprises the polyhydric alcohol compound (b2-1) and an aromatic ring-containing polyhydric alcohol compound (b2-2.1) having an aromatic ring, as described in claim 1 or 2, for a two-component curable composition for coating the inner wall of a water pipe.

6. The two-component curable composition for coating the inner wall of a water pipe according to claim 1, wherein the amine value of each compound constituting the primary or secondary amine compound component (b1) is in the range of 20 mg KOH / g or more and 800 mg KOH / g or less.

7. The water pipe is a drain pipe, as described in claim 1 or 2, a two-component curable composition for coating the inner wall of a water pipe.

8. A cured product obtained by curing a two-component curable composition for coating the inner wall of a water pipe according to claim 1 or 2.

9. The water pipe itself, The hardened material according to claim 8 is coated on the inner wall of the water pipe body, Water pipes with inner wall coating.

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