Polyisocyanate composition, paint composition, and coating film

Abstract

The polyisocyanate composition contains a polyisocyanate component (A1) obtained from a diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and a polyester polyol having an average of two or three functional groups or a polyisocyanate component (A2) obtained from a diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and a polyester polyol having an average of two or three functional groups and a polyoxyalkylene polyol having an average of two to four functional groups and a polyisocyanate component (B) obtained from a diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and a C1 to 20 monoalcohol, in which component (B) the molar ratio (allophanate groups / isocyanurate groups) is from 100 / 0 to 70 / 30. The proportion of the component (A1) or (A2) to the total weight of the component (A1) or (A2) and the component (B) is 60 mass% or more.

Description

[Technical Field]

[0001] This invention relates to polyisocyanate compositions, paint compositions, and coating films. This application claims priority based on Japanese Patent Application No. 2023-001167, filed in Japan on January 6, 2023, Japanese Patent Application No. 2023-001168, filed in Japan on January 6, 2023, and Japanese Patent Application No. 2023-106875, filed in Japan on June 29, 2023, and the contents thereof are incorporated herein by reference. [Background technology]

[0002] Among polyurea coating compositions, aliphatic polyaspalatic coating compositions are formed from aspartic acid ester compounds containing amino groups and aliphatic and / or alicyclic polyisocyanate compositions containing isocyanate groups. The yellowing of the coating film due to ultraviolet exposure, a drawback of aromatic polyurea coating compositions, is significantly reduced, and they have been conventionally used in a wide range of applications such as various coatings, flooring materials, and waterproofing materials.

[0003] Aspartic acid ester compounds have lower viscosity compared to the main polyol component of polyurethane coating compositions, and because they significantly reduce the amount of diluent in polyaspartic coating compositions, high-solid and solvent-free formulations are possible. Furthermore, because the amino group of the aspartic acid ester compound reacts quickly with the isocyanate group of aliphatic and / or alicyclic polyisocyanates, polyaspartic coating compositions have the advantage of faster curing speed at room temperature and superior mechanical strength compared to polyurethane coating compositions.

[0004] For example, Patent Document 1 discloses a polyaspalatic coating composition, which is an aliphatic polyurea coating composition comprising a polyamine component containing a secondary amino group having an aspartic acid ester skeleton and a polyisocyanate component containing an isocyanate group in an aliphatic polyisocyanate composition. This coating composition has the advantage of having a relatively long pot life and high coating hardness, and can be applied without using a high-pressure impact mixing spray machine. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 3-43472 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The polyaspartic coating composition disclosed in Patent Document 1 has room for further improvement in terms of the elongation rate of the coating film using the polyaspartic coating composition. To improve elongation, a curing agent suitable for use in polyasparatic coating compositions is required.

[0007] Furthermore, depending on the composition of the curing agent, it may be prone to crystallization, causing it to become cloudy. When applied to a polyaspartic coating composition, this can make it difficult to achieve uniformity in the coating film. Therefore, curing agents suitable for use in polyaspartic coating compositions are also required to be less prone to clouding.

[0008] The present invention has been made in view of the above circumstances, and aims to provide a polyisocyanate composition that can be used as a suitable curing agent for polyaspartic coating compositions, has high transparency, and can impart excellent elongation to the resulting coating film, as well as a coating composition and coating film using the same. [Means for solving the problem]

[0009] The present invention encompasses the following embodiments. [1] A polyisocyanate composition comprising component (A) and component (B), The aforementioned component (A) is either component (A1) or component (A2), The aforementioned component (A1) is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a polyester polyol having an average number of functional groups of 2 or 3. The aforementioned component (A2) is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, a polyester polyol having an average number of 2 or 3 functional groups, and a polyoxyalkylene polyol having an average number of 2 to 4 functional groups. The aforementioned component (B) is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a monoalcohol having 1 to 20 carbon atoms, wherein the molar ratio of allophanate groups to isocyanurate groups (allophanate group / isocyanurate group) is 100 / 0 to 70 / 30. A polyisocyanate composition in which the ratio of component (A) to the total amount of component (B) is 60% by mass or more. [2] The polyisocyanate composition according to [1], wherein the average number of functional groups of the polyester polyol is 3. [3] The number average molecular weight of the polyester polyol is 250 or more and 4000 or less. The polyisocyanate composition according to [2], wherein the number average molecular weight of the polyoxyalkylene polyol is 200 or more and 1500 or less. [4] The polyisocyanate composition according to [1], wherein the average number of functional groups of the polyester polyol is 2. [5] The number average molecular weight of the polyester polyol is 250 or more and 4000 or less. The polyisocyanate composition according to [4] above, wherein the number average molecular weight of the polyoxyalkylene polyol is 100 or more and 2000 or less. [6] The polyisocyanate composition according to any one of [1] to [5] above, containing either one or both of an ultraviolet absorber and a light stabilizer. [7] A coating composition containing a main agent and a curing agent, wherein the main agent is an aspartic acid ester compound represented by the following formula (I), and the curing agent is the polyisocyanate composition according to any one of [1] to [6] above.

[0010] [Chemical formula]

[0011] [In formula (I), X is an n-valent organic group obtained by removing the primary amino group of an n-valent polyamine, R 1 and R 2 are the same or different organic groups that are inert to isocyanate groups under the reaction conditions, and n is an integer of 2 or more. ] [8] The coating composition according to [7] above, which is a paint for architectural structures. [9] A coating film obtained by curing the coating composition according to [7] above. [Advantages of the Invention]

[0012] According to the present invention, there can be provided a polyisocyanate composition that can be suitably used as a curing agent for a polyaspartic coating composition and can impart excellent weather resistance, elongation rate, and / or low-temperature elongation to the resulting coating film, a coating composition using the same, and a coating film. [Modes for Carrying Out the Invention]

[0013] The following describes in detail embodiments for carrying out the present invention (hereinafter referred to as "this embodiment"). However, the present invention is not limited to the following embodiments. The present invention can be implemented by modifying it as appropriate within the scope of its gist.

[0014] In this specification, "polyol" means a compound having two or more hydroxyl groups (-OH).

[0015] In this specification, "polyisocyanate" means a reaction product (polymer) formed by bonding multiple monomer compounds (monomers) having one or more isocyanate groups (-NCO).

[0016] <Polyisocyanate composition> This embodiment is a polyisocyanate composition comprising component (A) and component (B), The aforementioned component (A) is either component (A1) or component (A2), The aforementioned component (A1) is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a polyester polyol having an average number of functional groups of 2 or 3. The aforementioned component (A2) is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, a polyester polyol having an average number of 2 or 3 functional groups, and a polyoxyalkylene polyol having an average number of 2 to 4 functional groups. The aforementioned component (B) is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a monoalcohol having 1 to 20 carbon atoms, wherein the molar ratio of allophanate groups to isocyanurate groups (allophanate group / isocyanurate group) is 100 / 0 to 70 / 30. The ratio of component (A) to the total amount of component (B) is 60% by mass or more.

[0017] The polyisocyanate composition of this embodiment can be suitably used as a curing agent for polyaspartic coating compositions mainly composed of aspartic acid ester compounds.

[0018] <First Embodiment> (A) Ingredients Component (A) is either component (A1) or component (A2).

[0019] (A1) component In the first embodiment of this present invention, component (A1) is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a polyester polyol having an average number of functional groups of 3.

[0020] ·Diisocyanate The diisocyanate monomer used in the first embodiment is selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates. Aliphatic diisocyanates and alicyclic diisocyanates are collectively referred to as diisocyanates.

[0021] Aliphatic diisocyanates are compounds that have only aliphatic groups in their molecules. The aliphatic diisocyanates used in this embodiment are not particularly limited, but are preferably aliphatic diisocyanates having 4 to 30 carbon atoms, such as tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (hereinafter abbreviated as "HDI"), 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, and lysine diisocyanate. Among these, HDI is more preferred due to its ease of industrial availability. The aliphatic diisocyanates listed above may be used individually or in combination of two or more.

[0022] Alicyclic diisocyanates are compounds having a cyclic aliphatic group in their molecule. The alicyclic diisocyanates used in this embodiment are not particularly limited, but are preferably alicyclic diisocyanates having 8 to 30 carbon atoms. Examples include isophorone diisocyanate (hereinafter abbreviated as "IPDI"), 1,3-bis(isocyanatomethyl)-cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, norbornene diisocyanate, and hydrogenated xylylene diisocyanate. Among these, IPDI is more preferred due to its weather resistance and ease of industrial availability. The alicyclic diisocyanates listed above may be used individually or in combination of two or more.

[0023] As diisocyanate monomers, a combination of one or more aliphatic diisocyanates and one or more alicyclic diisocyanates can also be used.

[0024] • Polyester polyols with an average number of 3 functional groups Polyester polyols with an average number of 3 functional groups are trivalent polyols containing repeating units represented by -O(CH2)5CO-, and can be derived from trivalent alcohols and ε-caprolactone, etc. While not particularly limited, they can also be obtained, for example, by ring-opening polymerization of ε-caprolactone, etc., with a trivalent alcohol as an initiator in the presence of a catalyst. The polyester polyol having an average number of functional groups of 3 is preferably a polycaprolactone polyol having an average number of functional groups of 3.

[0025] Polyester polyols with an average number of functional groups of 3 can also be obtained by condensing a dibasic acid (either alone or a mixture of two or more) with a polyhydric alcohol (either alone or a mixture of two or more).

[0026] Examples of the aforementioned dibasic acids include succinic acid, adipic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, succinic anhydride, maleic acid, phthalic acid, glutaric acid, speric acid, azelaic acid, sebacic acid, decandioic acid, itaconic acid, itaconic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, tetrahydrophthalic acid, tetrahydrophthalic acid, and other carboxylic acids.

[0027] Examples of the aforementioned polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, 2-ethyl-1,3-hexanediol, trimethylolpropane, glycerin, pentaerythritol, 2-methylolpropanediol, ethoxylated trimethylolpropane, 1,3-propanediol, pentane-1,5-diol, heptane-1,7-diol, octane-1,8-diol, nonane-1,9-diol, decane-1,10- Examples include diols, dodecane-1,12-diol, cyclohexane-1,4-dimethanol, 4,4'-(1-methylethylidene)biscyclohexanol, 1,1,1-trimethylolethane, hexane-1,2,6-triol, dipropylene glycol, propane-1,2-diol, butane-1,3-diol, hexane-1,2-diol, 2-methylpentane-2,4-diol, 3-methyl-1,5-pentanediol, octane-1,2-diol, 2-butyl-2-ethylpropane-1,3-diol, decane-1,2-diol, and 2-methyl-1,3-propanediol.

[0028] When a polyisocyanate composition using a polyester polyol with an average number of functional groups of 3 is used as a curing agent, and an aspartic acid ester compound is used as the main component, the compatibility between the main component and the curing agent is increased. For this reason, the polyisocyanate composition of this embodiment can be suitably used as a curing agent for polyaspartic coating compositions that use an aspartic acid ester compound as the main component. Furthermore, by using a polyester polyol with an average number of functional groups of 3, it is possible to produce a coating film that exhibits high flexibility through three-dimensional crosslinking, has high elongation, and excellent weather resistance.

[0029] The number-average molecular weight of a polyester polyol with an average number of 3 functional groups is preferably 250 to 4000, more preferably 250 to 1500, even more preferably 250 to 1000, particularly preferably 300 to 1000, and most preferably 500 to 900.

[0030] If the number-average molecular weight of a polyester polyol with an average number of functional groups of 3 is above the above lower limit, a coating film with high elongation can be produced when used as a curing agent in a polyaspartic coating composition mainly composed of an aspartic acid ester compound. When the number-average molecular weight of a polyester polyol with an average number of 3 functional groups is below the above upper limit, the paint composition is more likely to maintain a low viscosity when used as a curing agent for a polyaspartic paint composition mainly composed of an aspartic acid ester compound. For this reason, the polyisocyanate composition of this embodiment can be suitably used as a curing agent for a polyaspartic paint composition mainly composed of an aspartic acid ester compound. The number-average molecular weight of a polyester polyol with an average number of functional groups of 3 is the number-average molecular weight based on polystyrene, measured by gel permeation chromatography (hereinafter abbreviated as "GPC"), and can be measured by the method described in the examples below.

[0031] Trihydric alcohols such as trimethylolpropane and glycerin can be used as initiators.

[0032] Preferably used catalysts include organotitanium compounds such as tetrabutyl titanate, tetrapropyl titanate, and tetraethyl titanate, and tin compounds such as tin octoate, dibutyltin oxide, dibutyltin laurate, stannous chloride, and stannous bromide. From the viewpoint of easily adjusting the content of polyester polyols with an average functional group count of 3, tin compounds are preferred as catalysts.

[0033] Ring-opening polymerization of ε-caprolactone and the like is preferably carried out in a nitrogen gas atmosphere, with ε-caprolactone and the above-mentioned initiator charged in a molar ratio set to a predetermined molecular weight, and then 0.1 ppm to 100 ppm of catalyst added to the ε-caprolactone, followed by reaction at a temperature of 150°C to 200°C for 4 to 10 hours. However, it is important to control the caprolactone dimer content at the end of the reaction so that it is between 100 ppm and 1000 ppm. If necessary, the caprolactone dimer may be removed from the resulting polycaprolactone polyol by methods such as extraction or distillation. In addition to ε-caprolactone, other cyclic lactones such as trimethylcaprolactone and valerolactone may be mixed in to some extent.

[0034] A method for producing the polyester polyol having an average number of 3 can be, for example, by carrying out a known condensation reaction between a dibasic acid (either alone or a mixture) and a polyhydric alcohol (either alone or a mixture). For example, this can be done by combining the dibasic acid component and the polyhydric alcohol component and heating them at approximately 160-220°C.

[0035] In component (A1), the amount of polyester polyol having an average number of functional groups of 3 per 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates is preferably 10 to 80 parts by mass, and more preferably 30 to 45 parts by mass.

[0036] ·(A2) Component In the first embodiment of this present invention, component (A2) is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, a polyester polyol having an average number of functional groups of 3, and a polyoxyalkylene polyol having an average number of functional groups of 2 to 4.

[0037] ·Diisocyanate As the diisocyanate, a monomer similar to the diisocyanate in component (A1) above can be used.

[0038] • Polyester polyols with an average number of 3 functional groups As a polyester polyol having an average number of 3 functional groups, a polymer similar to the polyester polyol having an average number of 3 functional groups in component (A1) can be used.

[0039] • Polyoxyalkylene polyol Polyoxyalkylene polyols are -O(CH2) m A polyol with a valency of 2 to 4, containing a repeating unit represented by -(wherein m is an integer of 2 or more, preferably an integer between 3 and 5, and more preferably 3 or 4), which can be derived from a valency of 2 to 4, an alcohol, and ethylene oxide, propylene oxide, tetrahydrofuran, etc. Furthermore, although not particularly limited, it can be obtained by cationic polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc., using a valency of 2 to 4 as an initiator in the presence of a catalyst. The polyoxyalkylene polyol is preferably polytetramethylene glycol.

[0040] The number-average molecular weight of the polyoxyalkylene polyol is preferably between 200 and 1500, and more preferably between 200 and 1000. When the number-average molecular weight of the polyoxyalkylene polyol is above the above lower limit, a coating with high elongation can be produced when used as a curing agent in a polyaspartic coating composition mainly composed of an aspartic acid ester compound. When the number-average molecular weight of the polyoxyalkylene polyol is below the above upper limit, the paint composition is more likely to maintain a low viscosity when used as a curing agent for a polyaspartic paint composition mainly composed of an aspartic acid ester compound. For this reason, the polyisocyanate composition of this embodiment can be suitably used as a curing agent for a polyaspartic paint composition mainly composed of an aspartic acid ester compound. The number-average molecular weight of polyoxyalkylene polyols is the number-average molecular weight relative to polystyrene, as measured by GPC, and can be measured by the method described in the examples below.

[0041] As initiators, dihydric alcohols such as ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, and neopentyl glycol are used; trihydric alcohols such as trimethylolpropane and glycerin are used; and tetrahydric alcohols such as pentaerythritol are used. As catalysts, hydroxides such as lithium, sodium, and potassium, or strongly basic catalysts such as alkoxides and alkylamines can be used.

[0042] Cationic polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc. is preferably carried out in a nitrogen gas atmosphere, with the ethylene oxide, propylene oxide, tetrahydrofuran, etc. and the above-mentioned initiator set in a molar ratio to achieve a predetermined molecular weight, and then a catalyst is added to the ethylene oxide, propylene oxide, tetrahydrofuran, etc. in an amount of 0.1 ppm to 100 ppm by mass, and the reaction is carried out at a temperature of 150°C to 200°C for 4 to 10 hours.

[0043] In component (A2), the amount of polyester polyol having an average number of functional groups of 3 per 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates is preferably, for example, 1 to 50 parts by mass, and more preferably 5 to 10 parts by mass. In component (A2), the amount of polyoxyalkylene polyol having an average number of functional groups of 2 to 4 is preferably 1 to 50 parts by mass, and more preferably 10 to 20 parts by mass, relative to 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

[0044] The isocyanate content of component (A) (hereinafter also referred to as "NCO content") is preferably 5% by mass or more and 30% by mass or less based on the total amount of component (A) (100% by mass). The NCO content is more preferably 6% by mass or more, and even more preferably 7% by mass or more. The NCO content is more preferably 25% by mass or less, even more preferably 20% by mass or less, and even more preferably 10% by mass or less. When the NCO content is above the lower limit, it is easier to maintain the drying properties and curing properties of the coating film. When the NCO content is below the upper limit, it is easier to improve the scratch resistance of the resulting coating film when used as a curing agent for a polyaspartic coating composition. The NCO content of component (A) can be measured by the method described in the examples below.

[0045] The viscosity of component (A) at 25°C is preferably 500 mPa.s or more and 50,000 mPa.s or less. A viscosity of 1,000 mPa.s or more is more preferable, 1,500 mPa.s or more is even more preferable, and 2,000 mPa.s or more is particularly preferable. A viscosity of 40,000 mPa.s or less is more preferable, 30,000 mPa.s or less is even more preferable, 25,000 mPa.s or less is even more preferable, and 5,000 mPa.s or less is particularly preferable. If the viscosity is above the lower limit, when used as a curing agent for a polyaspartic coating composition, it is easier to improve the scratch resistance of the resulting coating film. If the viscosity is below the upper limit, it is easier to maintain drying properties. The viscosity of component (A) is measured at 25°C using an E-type viscometer and can be measured by the method described in the examples below.

[0046] The number average molecular weight of component (A) is preferably 250 to 4000. More preferably 300 to 3000, even more preferably 300 to 2500, even more preferably 400 to 2000, and particularly preferably 500 to 1700. When the number average molecular weight is above the lower limit, it is easier to improve the scratch resistance of the resulting coating when used as a curing agent for a polyaspartic coating composition. When the number average molecular weight is below the upper limit, it is easier to maintain drying properties. The number average molecular weight of component (A) is the number average molecular weight based on polystyrene measured by GPC, and can be measured by the method described in the examples below.

[0047] The average number of isocyanate groups in component (A) is preferably 2.0 or more and 10.0 or less. More preferably 2.2 or more, even more preferably 2.4 or more, particularly preferably 2.6 or more, and especially preferably 2.8 or more. More preferably 9.0 or less, even more preferably 8.0 or less, even more preferably 7.0 or less, and particularly preferably 4.0 or less. When the average number of isocyanate groups is above the lower limit, it is easier to maintain drying properties. When the average number of isocyanate groups is below the upper limit, it is easier to improve the scratch resistance and weather resistance of the resulting coating film when used as a curing agent for a polyaspartic coating composition. The average number of isocyanate groups in component (A) can be measured by the method described in the examples below.

[0048] The mass concentration of the diisocyanate monomer in component (A) is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.3% by mass or less, based on the total amount of component (A) (100% by mass). By keeping the diisocyanate monomer mass concentration below the above upper limit, it is easier to maintain drying properties. The diisocyanate monomer mass concentration of component (A) can be measured by gas chromatography analysis using the method described in the examples below.

[0049] ≪(A) Method for Manufacturing Component≫ (A) Component can be produced by the method described in International Publication No. 2018 / 163959. Specifically, component (A) can be obtained by carrying out a urethane reaction in the presence of an excess of diisocyanate monomer, in which the isocyanate group of the diisocyanate monomer reacts with the hydroxyl group of a polyester polyol and / or polyoxyalkylene polyol to form a urethane group, and then removing the unreacted diisocyanate monomer.

[0050] Component (A1) can be obtained, for example, by adding 10 to 80 parts by mass, preferably 30 to 45 parts by mass, of a polyester polyol having an average number of 3 functional groups to 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, carrying out a urethane reaction, and then removing the unreacted diisocyanate monomer.

[0051] Component (A2) can be obtained, for example, by adding 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, 1 to 50 parts by mass, preferably 5 to 10 parts by mass, of a polyester polyol having an average number of 3 functional groups, and 1 to 50 parts by mass, preferably 10 to 20 parts by mass, of a polyoxyalkylene polyol having an average number of 2 to 4 functional groups, to a urethane reaction, and then removing the unreacted diisocyanate monomer.

[0052] ≪(B) Component≫ Component (B) in the first embodiment of this embodiment is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a monoalcohol having 1 to 20 carbon atoms, wherein the molar ratio of allophanate groups to isocyanurate groups (allophanate group / isocyanurate group) is 100 / 0 to 70 / 30.

[0053] ·Diisocyanate The description of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates in component (B) is the same as the description of the diisocyanate monomer in component (A) above.

[0054] • Monoalcohols with 1 to 20 carbon atoms The number of carbon atoms in a monoalcohol having 1 to 20 carbon atoms is preferably 2 or more, more preferably 3 or more, particularly preferably 4 or more, and most preferably 6 or more. The number of carbon atoms in a monoalcohol having 1 to 20 carbon atoms is preferably 16 or less, more preferably 12 or less, and particularly preferably 9 or less. Monoalcohols may be used individually or as a mixture of two or more. The monoalcohols used in this invention may contain ether groups, ester groups, or carbonyl groups in their molecules, but monoalcohols consisting of saturated hydrocarbon groups are preferred. Furthermore, branched monoalcohols are more preferred.

[0055] Examples of such monoalcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, isoamyl alcohol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, 3,3,5-trimethyl-1-hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol, cyclopentanol, cyclohexanol, methylcyclohexanol, and trimethylcyclohexanol. Among these, isobutanol, n-butanol, isoamyl alcohol, 1-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol, and 1,3,5-trimethylcyclohexanol are more preferred. Alternatively, 1-propanol, isobutanol, 1-butanol, isoamyl alcohol, pentanol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, and 3,3,5-trimethyl-1-hexanol are preferred. Among these, 1-hexanol, 2-hexanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, and 3,3,5-trimethyl-1-hexanol are preferred, and 2-ethyl-1-hexanol is more preferred.

[0056] Component (B) has a molar ratio of allophanate group to isocyanurate group of 100 / 0 to 70 / 30, preferably 99 / 1 to 70 / 30. The molar ratio of allophanate group to isocyanurate group is preferably 98 / 2 or less, more preferably 97 / 3 or less. The molar ratio of allophanate group to isocyanurate group is preferably 74 / 26 or more, more preferably 77 / 23 or more, even more preferably 80 / 20 or more, and particularly preferably 90 / 10 or more. When the molar ratio of allophanate group to isocyanurate group falls within the above range, sufficient curability is achieved.

[0057] The molar ratio of the allophanate group to the isocyanurate group is: 1 This can be determined by 1H-NMR. Polyisocyanate compositions using hexamethylene diisocyanate and isocyanate prepolymers obtained therefrom as raw materials. 1 An example of a method using H-NMR is shown below.

[0058] 1 Example of H-NMR measurement method (B) Component is dissolved in deuterium chloroform at a concentration of 10% by mass (0.03% by mass of tetramethylsilane is added to component (B)). The chemical shift standard is set to 0 ppm for the hydrogen signal of tetramethylsilane. 1 The signal is measured using 1H-NMR, and the area ratio of the signal from hydrogen atoms bonded to the nitrogen of the allophanate group at around 8.5 ppm (1 mole of hydrogen atoms per mole of allophanate group) and the signal from hydrogen atoms of the methylene group adjacent to the isocyanurate group at around 3.85 ppm (6 moles of hydrogen atoms per mole of isocyanurate group) is measured. Allophanate group / Isocyanurate group = (Signal area around 8.5 ppm) / (Signal area around 3.85 ppm / 6)

[0059] Furthermore, since uretdione compounds readily dissociate due to heat or other factors to produce HDI, it is preferable to reduce the uretdione compound content. The content of the uretdione form is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less with respect to the polyisocyanate composition. The content of the uretdione form can be determined by measuring the ratio of the area of the peak with a molecular weight of about 336 in gel filtration chromatography (hereinafter referred to as GPC) using a differential refractometer. When there is a peak that hinders the measurement near the peak with a molecular weight of about 336, FT-IR is used to measure the ratio of the height of the peak of the uretdione group at about 1770 cm -1 to the height of the peak of the allophanate group at about 1720 cm -1 using an internal standard. It can also be determined by a method of quantifying the ratio of the height of the peak of the allophanate group at about 1720 cm

[0060] Hereinafter, the measurement method of GPC will be described. The measured value regarding the molecular weight of the component (B) can be obtained by the following measurement method. Equipment used: HLC-8120 (manufactured by Tosoh Corporation), columns used: TSK GEL SuperH1000, TSK GEL SuperH2000, TSK GEL SuperH3000 (all manufactured by Tosoh Corporation), sample concentration: 5 wt / vol% (for example, 50 mg of the sample is dissolved in 1 ml of THF), carrier: THF, detection method: differential refractometer, flow rate 0.6 ml / min., column temperature 40°C). The calibration curve of GPC is prepared using polystyrene with a molecular weight of 50,000 to 2,050 (PSS-06 (Mw 50,000), BK13007 (Mp = 20,000, Mw / Mn = 1.03), PSS-08 (Mw = 9,000), PSS-09 (Mw = 4,000), 5040-35125 (Mp = 2,050, Mw / Mn = 1.05) manufactured by GL Sciences Inc.), trimers to heptamers of the isocyanurate form of a hexamethylene diisocyanate-based polyisocyanate composition (Duranate TPA-100, manufactured by Asahi Kasei Corporation) (isocyanurate trimer molecular weight = 504, isocyanurate pentamer molecular weight = 840, isocyanurate heptamer molecular weight = 1176) and HDI (molecular weight = 168) as standards.

[0061] A high content of urethane is undesirable because it reduces the crosslinking ability of the polyisocyanate composition. The amount of urethane contained in the polyisocyanate composition of the present invention is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0062] Furthermore, since the solubility of biuret and other diisocyanate polymers decreases, it is undesirable for their content to be high. The range of amounts of biuret and other diisocyanate polymers contained in the polyisocyanate composition of the present invention is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0063] In component (B), it is preferable that, for example, 1 to 20 parts by mass, preferably 1 to 10 parts by mass, of a monoalcohol having 1 to 20 carbon atoms is blended with 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

[0064] The isocyanate group content (hereinafter referred to as NCO content) of component (B) is 10 to 22% by mass in a substantially solvent- and diisocyanate-free state, preferably 13 to 21% by mass, and more preferably 16 to 20% by mass. Within the range of 10 to 22% by mass, a polyisocyanate composition with good compatibility with component (A) and sufficient crosslinking properties can be obtained.

[0065] The viscosity of component (B) is preferably 50 to 500 mPa.s in a state that is substantially free of solvents and diisocyanates. The viscosity of component (B) is preferably 75 mPa.s or higher, and more preferably 90 mPa.s or higher. The viscosity of component (B) is preferably 450 mPa.s or lower, more preferably 400 mPa.s or lower, even more preferably 350 mPa.s or lower, and particularly preferably 300 mPa.s or lower. If the viscosity of component (B) is 50 mPa.s or higher, a polyisocyanate composition with sufficient crosslinking properties can be obtained. If the viscosity of component (B) is 500 mPa.s or lower, it is possible to obtain a polyisocyanate composition with reduced volatile organic compound (VOC) content. The viscosity of component (B) is measured at 25°C using an E-type viscometer and can be measured by the method described in the examples below.

[0066] The average number of isocyanate groups in component (B) is preferably 1.8 to 2.5. The average number of isocyanate groups in component (B) is more preferably 2.0 or more. The average number of isocyanate groups in component (B) is preferably 2.4 or less, and more preferably 2.3 or less. When the average number of isocyanate groups and the average number of functional groups are in the range of 2.0 to 2.5, the curing properties when it is made into a coating film are good. The average number of isocyanate groups can be calculated using the following formula. Average number of isocyanate groups = [Number average molecular weight × NCO content (%)] / 4200 The number-average molecular weight can be determined by GPC measurement.

[0067] ≪(B) Method for producing component≫ Component (B) can be obtained, for example, by urethane-forming 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and 1 to 20 parts by mass, preferably 1 to 10 parts by mass, of a monoalcohol having 1 to 20 carbon atoms, then adding an allophanate-forming catalyst to carry out an allophanate-forming reaction, stopping the reaction, and removing unreacted diisocyanate monomers.

[0068] ≪Ratio of components (A) and (B)≫ In this embodiment, the ratio of component (A) to the total amount of component (B) is 60% by mass or more. In this embodiment, the ratio of component (A) to the total amount of component (A) and component (B) is preferably 99% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less, and particularly preferably 80% by mass or less. In this embodiment, the ratio of component (A) to the total amount of component (A) and component (B) is preferably 60% by mass or more and 95% by mass or less, more preferably 60% by mass or more and 90% by mass or less, and even more preferably 60% by mass or more and 80% by mass or less.

[0069] (A) When the content ratio of component (A) is within the above range, a polyisocyanate composition can be obtained that can be used as a curing agent suitable for use in polyaspartic coating compositions and that can impart excellent elongation to the resulting coating film. (A) When the content ratio of component is above the lower limit, a coating film with high flexibility and high elongation can be produced through three-dimensional crosslinking. If the content of component (A) is below the above upper limit, component (B) disrupts the orientation of component (A1) or component (A2). As a result, the crystallization of component (A) is disrupted, making it possible to produce a coating film with high elongation.

[0070] The NCO content of the polyisocyanate composition is preferably 5% by mass or more and 30% by mass or less, relative to the total amount (100% by mass) of components (A) and (B). More preferably, the NCO content is 6% by mass or more, and even more preferably 7% by mass or more. More preferably, the NCO content is 30% by mass or less, even more preferably 25% by mass or less, even more preferably 15% by mass or less, and particularly preferably 13% by mass or less. When the NCO content is above the lower limit, the drying properties and curability of the resulting coating film are more easily maintained when used as a curing agent for a polyaspartic coating composition. When the NCO content is below the upper limit, a coating film with high elongation can be produced when used as a curing agent for a polyaspartic coating composition. The NCO content can be measured by the method described in the examples below.

[0071] The viscosity of the polyisocyanate composition at 25°C is preferably 500 mPa.s to 4000 mPa.s. A viscosity of 3000 mPa.s or less is more preferable, 2000 mPa.s or less is even more preferable, and 1350 mPa.s or less is particularly preferable. A viscosity of 1000 mPa.s or more is even more preferable. If the viscosity is above the lower limit, when used as a curing agent for polyaspartic coating compositions, it is possible to produce coatings with high film elongation. If the viscosity is below the upper limit, it is easier to maintain weather resistance. The viscosity of the polyisocyanate composition is measured at 25°C using an E-type viscometer and can be measured by the method described in the examples below.

[0072] The average number of isocyanate groups in the polyisocyanate composition is preferably 1.8 or more and 10.0 or less. More preferably 2.0 or more, and particularly preferably 2.8 or more. More preferably 10.0 or less, even more preferably 5.0 or less, and particularly preferably 3.5 or less. When the average number of isocyanate groups is above the lower limit, it is easier to maintain the weather resistance of the resulting coating film when used as a curing agent for a polyaspartic coating composition. When the average number of isocyanate groups is below the upper limit, when used as a curing agent for a polyaspartic coating composition, it is possible to produce a coating film with high elongation. The average number of isocyanate groups in a polyisocyanate composition can be measured by the method described in the examples below.

[0073] ≪Optional ingredients≫ In this embodiment, it is preferable that the polyisocyanate composition contains either an ultraviolet absorber or a light stabilizer, or both.

[0074] While not particularly limited, examples of UV absorbers include benzotriazole compounds, triazine compounds, benzophenone compounds, and cyanoacrylate compounds.

[0075] Benzotriazole compounds are not particularly limited, but examples include Tinuvin P·PS·99-2·213·234·326·329·360·384-2·571·900·928·970·1130 (manufactured by BASF Japan Ltd.), Adeka Stab LA-24·29·31RG·31G·32·36·36RG·F70 (manufactured by ADEKA Corporation), and EVERSORB 70·71·72·73·74·75·76·77·78·79·80·81·82·88·89·109·234 (manufactured by Yongguang Chemical Industry Co., Ltd., Taiwan).

[0076] Triazine compounds are not particularly limited, but examples include Tinuvin 400·400-DW·405·460·477·479·479-DW·1577ED·1600 (manufactured by BASF Japan Ltd.) and EVERSORB 40·41FD·45 (manufactured by Yongguang Chemical Industries Ltd., Taiwan).

[0077] Benzophenone compounds are not particularly limited, but examples include Chimassorb 81·81FL (manufactured by BASF Japan Ltd.), Uvinul 3049·3050 (manufactured by BASF Japan Ltd.), Adeka Stab 1413 (manufactured by ADEKA Corporation), and EVERSORB 10·11·12·51·52 (manufactured by Yongguang Chemical Industry Co., Ltd., Taiwan).

[0078] The cyanoacrylate compounds are not particularly limited, but examples include Uvinul 3030FF, 3035, and 3039 (manufactured by BASF Japan Ltd.).

[0079] From the viewpoint of maintaining weather resistance over a long period, benzotriazole compounds, triazine compounds, and benzophenone compounds are preferred, with benzotriazole compounds and triazine compounds being more preferred.

[0080] While not particularly limited, examples of light stabilizers include hindered amine compounds.

[0081] Hindered amine compounds are not particularly limited, but examples include Tinuvin 111FDL·123·123-DW·PA144·152·249·292·783FDL·765 (manufactured by BASF Japan Ltd.), Adeka Stab LA-52·57·63P·68·72·77Y·77G·81·402AF (manufactured by ADEKA Corporation), and EVERSORB 60·61·90·91FD·93·94FD·95·765·S02 (manufactured by Yongguang Chemical Industry Co., Ltd., Taiwan).

[0082] If the polyisocyanate composition contains either an ultraviolet absorber or a light stabilizer, or both, the amount added is, for example, 10 ppm by mass or more and 15,000 ppm by mass or less.

[0083] In this embodiment, the polyisocyanate composition may contain an antioxidant. The hindered phenol antioxidant is not particularly limited, but examples include dibutylhydroxytoluene (hereinafter sometimes abbreviated as "BHT"), Irganox 1010 (trade name), Irganox 1135 (trade name), Irganox 1330 (trade name), Irganox 3114 (trade name), Irganox 565 (trade name), Irganox 1520L (trade name) (all manufactured by BASF), Adeka Stab AO-20 (trade name), Adeka Stab AO-30 (trade name), Adeka Stab AO-50 (trade name), Adeka Stab AO-60 (trade name), Adeka Stab AO-80 (trade name) (all manufactured by ADEKA Corporation).

[0084] <Second Embodiment> In the second embodiment of this model, the description of the same configuration as in the first embodiment may be omitted. (A) Ingredients Component (A) is either component (A1) or component (A2).

[0085] (A1) component Component (A1) is a polyisocyanate component obtained from at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates, and a polyester polyol having an average number of functional groups of 2.

[0086] ·Diisocyanate The diisocyanate used in the second embodiment is selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates. As the aliphatic diisocyanate and alicyclic diisocyanate, the monomers described in the first embodiment can be used in the same way, and HDI is preferably used.

[0087] • Polyester polyols with an average number of 2 functional groups Polyester polyols with an average number of functional groups of 2 are divalent polyols containing repeating units represented by -O(CH2)5CO-, and can be derived from a divalent alcohol and ε-caprolactone, etc. Furthermore, although not particularly limited, they can be obtained, for example, by ring-opening polymerization of ε-caprolactone, etc., with a divalent alcohol as an initiator in the presence of a catalyst.

[0088] Polyester polyols having an average number of functional groups of 2 can also be obtained by condensing a dibasic acid (either alone or a mixture of two or more) with a polyhydric alcohol (either alone or a mixture of two or more).

[0089] Examples of the aforementioned dibasic acids include succinic acid, adipic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, succinic anhydride, maleic acid, phthalic acid, glutaric acid, speric acid, azelaic acid, sebacic acid, decandioic acid, itaconic acid, itaconic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, tetrahydrophthalic acid, tetrahydrophthalic acid, and other carboxylic acids. Among these, adipic acid or sebacic acid is preferably used.

[0090] Examples of the aforementioned polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, 2-ethyl-1,3-hexanediol, trimethylolpropane, glycerin, pentaerythritol, 2-methylolpropanediol, ethoxylated trimethylolpropane, 1,3-propanediol, pentane-1,5-diol, heptane-1,7-diol, octane-1,8-diol, nonane-1,9-diol, and decane. Examples include -1,10-diol, dodecane-1,12-diol, cyclohexane-1,4-dimethanol, 4,4'-(1-methylethylidene)biscyclohexanol, 1,1,1-trimethylolethane, hexane-1,2,6-triol, dipropylene glycol, propane-1,2-diol, butane-1,3-diol, hexane-1,2-diol, 2-methylpentane-2,4-diol, 3-methyl-1,5-pentanediol, octane-1,2-diol, 2-butyl-2-ethylpropane-1,3-diol, decane-1,2-diol, and 2-methyl-1,3-propanediol. Among these, diethylene glycol, 1,3-butanediol, 1,4-butanediol, and 3-methyl-1,5-pentanediol are preferred.

[0091] The polyester polyol having an average number of 2 functional groups is preferably a polycaprolactone polyol having an average number of 2 functional groups, a polyester polyol that is a condensate of a dibasic acid and a polyhydric alcohol having an average number of 2 functional groups, or a mixture thereof.

[0092] When a polyisocyanate composition using a polyester polyol with an average number of functional groups of 2 is used as a curing agent, and an aspartic acid ester compound is used as the main component, the compatibility between the main component and the curing agent is increased. For this reason, the polyisocyanate composition of this embodiment can be suitably used as a curing agent for polyaspartic coating compositions that use an aspartic acid ester compound as the main component. Furthermore, by using a polyester polyol with an average number of functional groups of 2, high flexibility can be achieved through physical crosslinking, making it possible to produce coatings with high elongation, especially at low temperatures.

[0093] The number-average molecular weight of a polyester polyol with an average number of 2 functional groups is preferably 250 to 4000, more preferably 250 to 1500, even more preferably 250 to 1000, even more preferably 300 to 800, and particularly preferably 400 to 800. If the number-average molecular weight of a polyester polyol with an average number of functional groups of 2 is equal to or greater than the above lower limit, a coating film with high elongation can be produced when used as a curing agent in a polyaspartic coating composition mainly composed of an aspartic acid ester compound. When the number-average molecular weight of a polyester polyol with an average number of functional groups of 2 is below the above upper limit, the appearance of the polyisocyanate composition is easily improved. Furthermore, when used as a curing agent for a polyaspartic coating composition mainly composed of an aspartic acid ester compound, the coating composition is more likely to maintain a low viscosity. For this reason, the polyisocyanate composition of this embodiment can be suitably used as a curing agent for a polyaspartic coating composition mainly composed of an aspartic acid ester compound. The number-average molecular weight of a polyester polyol with an average number of functional groups of 2 is the number-average molecular weight based on polystyrene as measured by GPC, and can be measured by the method described in the examples below.

[0094] The method for producing polycaprolactone polyols involves using dihydric alcohols as initiators, such as ethylene glycol, propylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, pentaerythritol, 2-methylolpropanediol, 2-ethyl-1,3-hexanediol, 1,3-propanediol, pentane-1,5-diol, heptane-1,7-diol, and octa Non-1,8-diol, nonane-1,9-diol, decane-1,10-diol, dodecane-1,12-diol, cyclohexane-1,4-dimethanol, dipropylene glycol, propane-1,2-diol, butane-1,3-diol, hexane-1,2-diol, 2-methylpentane-2,4-diol, 3-methyl-1,5-pentanediol, octane-1,2-diol, 2-butyl-2-ethylpropane-1,3-diol, decane-1,2-diol, 2-methyl-1,3-propanediol, etc. can be used. Among these, diethylene glycol, 1,3-butanediol, 1,4-butanediol, and 3-methyl-1,5-pentanediol are preferred.

[0095] Preferably used catalysts include organotitanium compounds such as tetrabutyl titanate, tetrapropyl titanate, and tetraethyl titanate, and tin compounds such as tin octoate, dibutyltin oxide, dibutyltin laurate, stannous chloride, and stannous bromide. From the viewpoint of easily adjusting the content of polyester polyols with an average functional group count of 2, tin compounds are preferred as catalysts.

[0096] Ring-opening polymerization of ε-caprolactone and the like is preferably carried out in a nitrogen gas atmosphere, with ε-caprolactone and the above-mentioned initiator charged in a molar ratio set to a predetermined molecular weight, and then 0.1 ppm to 100 ppm of catalyst added to the ε-caprolactone, followed by reaction at a temperature of 150°C to 200°C for 4 to 10 hours. However, it is important to control the caprolactone dimer content at the end of the reaction so that it is between 100 ppm and 1000 ppm. If necessary, the caprolactone dimer may be removed from the resulting polycaprolactone polyol by methods such as extraction or distillation. In addition to ε-caprolactone, other cyclic lactones such as trimethylcaprolactone and valerolactone may be mixed in to some extent.

[0097] Polyester polyols can be produced, for example, by carrying out a known condensation reaction between a dibasic acid (either alone or a mixture) and a polyhydric alcohol (either alone or a mixture). For example, this can be done by combining a dibasic acid component and a polyhydric alcohol component and heating them at approximately 160-220°C.

[0098] In the second embodiment, component (A1) preferably contains, for example, 10 to 90 parts by mass, more preferably 20 to 50 parts by mass, of a polyester polyol having an average number of 2 functional groups, with respect to 100 parts by mass of at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates.

[0099] ·(A2) Component In the second embodiment of this embodiment, component (A2) is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, a polyester polyol having an average number of functional groups of 2, and a polyoxyalkylene polyol having an average number of functional groups of 2 to 4.

[0100] ·Diisocyanate The diisocyanate in component (A2) of the second embodiment can be the same monomer as the diisocyanate in component (A1) above, and HDI is preferably used.

[0101] • Polyester polyols with an average number of 2 functional groups As the polyester polyol having an average number of 2 functional groups in component (A2) of the second embodiment, the same polymer as the polyester polyol having an average number of 2 functional groups in component (A1) can be used.

[0102] • Polyoxyalkylene polyol Polyoxyalkylene polyols are -O(CH2) m A polyol with a valency of 2 to 4, containing a repeating unit represented by -(wherein m is an integer of 2 or more, preferably an integer between 3 and 5, and more preferably 3 or 4), which can be derived from a valency of 2 to 4, an alcohol, and ethylene oxide, propylene oxide, tetrahydrofuran, etc. Furthermore, although not particularly limited, it can be obtained by cationic polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc., using a valency of 2 to 4 as an initiator in the presence of a catalyst.

[0103] The number-average molecular weight of the polyoxyalkylene polyol is preferably between 100 and 2000, and more preferably between 200 and 1000. When the number-average molecular weight of the polyoxyalkylene polyol is above the above lower limit, a coating with high elongation can be produced when used as a curing agent in a polyaspartic coating composition mainly composed of an aspartic acid ester compound. When the number-average molecular weight of the polyoxyalkylene polyol is below the above upper limit, the paint composition is more likely to maintain a low viscosity when used as a curing agent for a polyaspartic paint composition mainly composed of an aspartic acid ester compound. For this reason, the polyisocyanate composition of this embodiment can be suitably used as a curing agent for a polyaspartic paint composition mainly composed of an aspartic acid ester compound. The number-average molecular weight of polyoxyalkylene polyols is the number-average molecular weight relative to polystyrene, as measured by GPC, and can be measured by the method described in the examples below.

[0104] Suitable initiators include dihydric alcohols such as ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, and neopentyl glycol; trihydric alcohols such as trimethylene glycol and glycerin; and tetrahydric alcohols such as pentaerythritol. From the viewpoint of obtaining a low-viscosity polyisocyanate component, branched polyhydric alcohols are preferred. As catalysts, hydroxides such as lithium, sodium, and potassium, or strongly basic catalysts such as alkoxides and alkylamines can be used.

[0105] Cationic polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc. is preferably carried out in a nitrogen gas atmosphere, with the ethylene oxide, propylene oxide, tetrahydrofuran, etc. and the above-mentioned initiator set in a molar ratio to achieve a predetermined molecular weight, and then a catalyst is added to the ethylene oxide, propylene oxide, tetrahydrofuran, etc. in an amount of 0.1 ppm to 100 ppm by mass, and the reaction is carried out at a temperature of 150°C to 200°C for 4 to 10 hours.

[0106] In component (A2) of the second embodiment, it is preferable that, for example, 10 to 50 parts by mass, preferably 10 to 30 parts by mass, of a polyester polyol having an average number of 2 functional groups and 10 to 50 parts by mass, preferably 10 to 30 parts by mass, of a polyoxyalkylene polyol having an average number of 2 to 4 functional groups, based on 100 parts by mass of at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates.

[0107] (A) Optional components Furthermore, component (A) may optionally contain a monoalcohol, diol, or triol having a branched chain with 2 to 20 carbon atoms. Monoalcohols may contain one or more groups selected from the group consisting of ether groups, ester groups, carbonyl groups, and phenyl groups in their molecule. For example, benzyl alcohol may be used, but monoalcohols consisting only of saturated hydrocarbon groups are preferred. Furthermore, branched monoalcohols are more preferred. Examples of such monoalcohols include 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, 3,3,5-trimethyl-1-hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol, cyclopentanol, cyclohexanol, methylcyclohexanol, and trimethylcyclohexanol.

[0108] Examples of diols include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, diethylene glycol, polyethylene glycol, and Examples include linear aliphatic diols such as repropylene glycol and polytetramethylene glycol; and branched aliphatic diols such as 1,3-butanediol, 2-ethyl-1,3-hexanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,2-octanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-diethyl-1,3-propanediol. These can be used individually or in combination of two or more. Among these, branched aliphatic diols are preferred because they can more effectively suppress crystallization.

[0109] Examples of trialcohols include glycerin and trimethylolpropane.

[0110] In particular, component (A) preferably contains a branched diol having 3 to 20 carbon atoms as an optional component, and more preferably contains a branched diol having 3 to 10 carbon atoms. By using a branched diol having 3 to 20 carbon atoms, crystallization of the paint composition can be further suppressed.

[0111] In the second embodiment, the isocyanate content of component (A) (hereinafter also referred to as "NCO content") is preferably 5% by mass or more and 30% by mass or less, based on the total amount of component (A) (100% by mass). The NCO content is more preferably 6% by mass or more, even more preferably 7% by mass or more, and particularly preferably 8% by mass or more. The NCO content is more preferably 25% by mass or less, and even more preferably 20% by mass or less. When the NCO content is above the lower limit, it is easier to maintain the drying properties and curing properties of the coating film. When the NCO content is below the upper limit, it is easier to improve the scratch resistance of the resulting coating film when used as a curing agent for a polyaspartic coating composition. The NCO content of component (A) can be measured by the method described in the examples below.

[0112] In the second embodiment, the viscosity of component (A) at 25°C is preferably 500 mPa.s or more and 10000 mPa.s or less. A viscosity of 600 mPa.s or more is more preferable, 700 mPa.s or more is even more preferable, and 1000 mPa.s or more is particularly preferable. A viscosity of 10000 mPa.s or less is more preferable, 5000 mPa.s or less is even more preferable, 2500 mPa.s or less is even more preferable, and 2000 mPa.s or less is particularly preferable. If the viscosity is above the lower limit, when used as a curing agent for a polyaspartic coating composition, it is easier to improve the scratch resistance of the resulting coating film. If the viscosity is below the upper limit, it is easier to maintain drying properties. The viscosity of component (A) is measured at 25°C using an E-type viscometer and can be measured by the method described in the examples below.

[0113] In the second embodiment, the number average molecular weight of component (A) is preferably 250 or more and 4000 or less. More preferably 300 or more, and particularly preferably 400 or more. More preferably 4000 or less, even more preferably 3000 or less, and particularly preferably 2000 or less. When the number average molecular weight is above the lower limit, it is easier to improve the scratch resistance of the resulting coating film when used as a curing agent for a polyaspartic coating composition. When the number average molecular weight is below the upper limit, it is easier to maintain drying properties. The number average molecular weight of component (A) is the polystyrene-based number average molecular weight measured by GPC, and can be measured by the method described in the examples below.

[0114] In the second embodiment, the average number of isocyanate groups in component (A) is preferably 2.0 or more and 10.0 or less. More preferably 2.2 or more, even more preferably 2.4 or more, and particularly preferably 2.6 or more. More preferably 9.0 or less, even more preferably 8.0 or less, even more preferably 7.0 or less, and particularly preferably 3.0 or less. When the average number of isocyanate groups is above the lower limit, it is easier to maintain drying properties. When the average number of isocyanate groups is below the upper limit, when used as a curing agent for a polyaspartic coating composition, it is easier to improve the scratch resistance and weather resistance of the resulting coating film. The average number of isocyanate groups in component (A) can be measured by the method described in the examples below.

[0115] In the second embodiment, the mass concentration of the diisocyanate monomer of component (A) is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.3% by mass or less, based on the total amount of component (A) (100% by mass). By keeping the diisocyanate monomer mass concentration below the above upper limit, it is easier to maintain drying properties. The diisocyanate monomer mass concentration of component (A) can be measured by the method described in the examples below.

[0116] ≪(A) Method for Manufacturing Component≫ Component (A) in the second embodiment can be manufactured by the same method as component (A) in the first embodiment.

[0117] Component (A1) in the second embodiment can be obtained, for example, by adding 10 to 90 parts by mass, preferably 20 to 50 parts by mass, of a polyester polyol having an average number of 2 functional groups to 100 parts by mass of at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates, carrying out a urethane reaction, and then removing the unreacted diisocyanate monomer.

[0118] Component (A2) in the second embodiment can be obtained, for example, by adding 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, 10 to 50 parts by mass, preferably 10 to 30 parts by mass, of a polyester polyol having an average number of 2 functional groups, and 10 to 50 parts by mass, preferably 10 to 30 parts by mass, of a polyoxyalkylene polyol having an average number of 2 to 4 functional groups, to a urethane reaction, and then removing the unreacted diisocyanate monomer.

[0119] ≪(B) Component≫ In the second embodiment, component (B) is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a monoalcohol having 1 to 20 carbon atoms, wherein the molar ratio of allophanate groups to isocyanurate groups (allophanate groups / isocyanurate groups) is 100 / 0 to 70 / 30.

[0120] ·Diisocyanate Aliphatic diisocyanates are compounds that contain only aliphatic groups in their molecule. On the other hand, alicyclic diisocyanates are compounds that contain cyclic aliphatic groups in their molecule. Using aliphatic diisocyanates is preferable because it results in a polyisocyanate compound with low viscosity. Examples of aliphatic diisocyanates include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (hereinafter referred to as HDI), trimethylhexamethylene diisocyanate, and lysine diisocyanate. Examples of alicyclic diisocyanates include isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and 1,4-diisocyanate cyclohexane. Among these, HDI, isophorone diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate are preferred because they are readily available industrially. Of these, HDI is the most preferred due to its excellent weather resistance and film flexibility.

[0121] • Monoalcohol In component (B) of the second embodiment, the same monoalcohol having 1 to 20 carbon atoms as the monoalcohol used in component (B) of the first embodiment can be used.

[0122] The molar ratio of allophanate group to isocyanurate group in component (B) of the second embodiment is the same as the molar ratio of allophanate group to isocyanurate group in component (B) of the first embodiment.

[0123] The content of uretdione, urethane, biuret, and other diisocyanate polymers in component (B) of the second embodiment is the same as the content in component (B) of the first embodiment.

[0124] ≪(B) Method for producing component≫ Component (B) of the second embodiment can be manufactured by the same method as component (B) of the first embodiment.

[0125] The NCO content, viscosity, and average number of isocyanate groups of component (B) in the second embodiment are the same as those described for the NCO content, viscosity, and average number of isocyanate groups of component (B) in the first embodiment.

[0126] ≪Ratio of components (A) and (B)≫ In the second embodiment, the ratio of component (A) to the total amount of component (B) is 60% by mass or more. In the second embodiment, the ratio of component (A) to the total amount of component (B) is preferably 99% by mass or less, more preferably 95% by mass or less, even more preferably 90% by mass or less, and particularly preferably 80% by mass or less. In the second embodiment, the ratio of component (A) to the total amount of component (A) and component (B) is preferably 60% by mass or more and 99% by mass or less, more preferably 60% by mass or more and 95% by mass or less, even more preferably 60% by mass or more and 90% by mass or less, and particularly preferably 60% by mass or more and 80% by mass or less.

[0127] (A) When the content ratio of component (A) is within the above range, a polyisocyanate composition can be obtained that can be used as a suitable curing agent for polyaspartic coating compositions and that can impart excellent elongation to the resulting coating film. Weather resistance can also be maintained. (A) When the content ratio of component (A) is within the above range, the polyaspartic coating composition exhibits suppressed crystallization, resulting in a highly transparent curing agent.

[0128] Polyester polyols having an average of 2 functional groups in component (A) are prone to crystallization. When crystallization occurs, the components forming the resulting coating film tend to be non-uniform. When component (A) and component (B) are included, and the content ratio of component (A) is within the above range, component (A) is less likely to crystallize, and a coating film with high uniformity is easily obtained.

[0129] The NCO content of the polyisocyanate composition of the second embodiment is preferably 5% by mass or more and 30% by mass or less, relative to the total amount (100% by mass) of components (A) and (B). More preferably, the NCO content is 6% by mass or more, and even more preferably 7% by mass or more. More preferably, the NCO content is 30% by mass or less, even more preferably 25% by mass or less, and particularly preferably 14% by mass or less. When the NCO content is above the lower limit, the drying properties and curability of the resulting coating film are more easily maintained when used as a curing agent for a polyaspartic coating composition. When the NCO content is below the upper limit, a coating film with high elongation can be produced when used as a curing agent for a polyaspartic coating composition. The NCO content can be measured by the method described in the examples below.

[0130] The viscosity of the polyisocyanate composition of the second embodiment at 25°C is preferably 500 mPa.s to 2000 mPa.s. More preferably 1700 mPa.s or less, even more preferably 1500 mPa.s or less, and particularly preferably 1250 mPa.s or less. If the viscosity is above the lower limit, when used as a curing agent for a polyaspartic coating composition, a coating film with high elongation can be produced. If the viscosity is below the upper limit, when used as a curing agent for a polyaspartic coating composition, the handling of the resulting coating composition is easily improved. The viscosity of the polyisocyanate composition is measured at 25°C using an E-type viscometer and can be measured by the method described in the examples below.

[0131] The average number of isocyanate groups in the polyisocyanate composition of the second embodiment is preferably 1.8 or more and 10.0 or less. The average number of isocyanate groups is more preferably 2.0 or more. The average number of isocyanate groups is more preferably 10.0 or less, even more preferably 5.0 or less, and particularly preferably 3.0 or less. When the average number of isocyanate groups is above the lower limit, it is easier to maintain the weather resistance of the resulting coating film when used as a curing agent for a polyaspartic coating composition. When the average number of isocyanate groups is below the upper limit, when used as a curing agent for a polyaspartic coating composition, it is possible to produce a coating film with high elongation. The average number of isocyanate groups in the polyisocyanate composition can be measured by the method described in the examples below.

[0132] ≪Optional ingredients≫ In the second embodiment, the optional components described in the first embodiment may be included in the same manner as in the first embodiment.

[0133] ≪Method for producing polyisocyanate compositions≫ The polyisocyanate composition of this embodiment (the first or second embodiment) can be produced by mixing component (A) and component (B) above, and any optional component as needed. For example, the mixing method is not particularly limited; it can be done by hand stirring, or by using stirring equipment such as a mixer. If necessary, a solvent may be added to adjust the viscosity.

[0134] <Paint composition> This embodiment is a paint composition comprising a main component and a curing agent. The main component is an aspartic acid ester compound represented by the following formula (I), and the curing agent is the polyisocyanate composition of the above embodiment (first embodiment or second embodiment).

[0135] [ka]

[0136] [In formula (I), X is an n-valent organic group obtained by removing the primary amino group of an n-valent polyamine, and R 1 and R 2 [where n is an integer greater than or equal to 2, and n is the same or a different organic group that is inert to the isocyanate group under the reaction conditions.]

[0137] (X) In general formula (I), X is an n-valent organic group.

[0138] The n-valent organic group may be an aliphatic group or an aromatic group. The aliphatic group may be linear, branched, or cyclic. Furthermore, n is an integer of 2 or more, as described later.

[0139] Examples of the linear or branched aliphatic groups include alkanediyl groups (alkylene groups), alkylidene groups, alkylidine groups, and the like.

[0140] Examples of the cyclic aliphatic group include cycloalkylene groups.

[0141] Examples of the aromatic group include arylene groups such as phenylene groups.

[0142] More specifically, X is preferably a linear, branched, or cyclic divalent aliphatic group having 2 to 20 carbon atoms, from the viewpoint of resistance to yellowing of the polyaspalatic coating composition of this embodiment. Examples of the linear, branched, or cyclic divalent aliphatic group having 2 to 20 carbon atoms include n-butylene group, n-pentylene group, n-hexylene group, 2,2,4-trimethylhexamethylene group, 2,4,4-trimethylhexamethylene group, 3,3,5-trimethyl-5-methylcyclohexylene group, dicyclohexylmethylene group, and 3,3'-dimethyldicyclohexylmethylene group.

[0143] (R 1 and R 2 ) In general formula (I), R 1and R 2 These are, independently, organic groups that are inert to the isocyanate group under the reaction conditions.

[0144] In this specification, "inert to isocyanate groups under reaction conditions" means R 1 and R 2 However, this means that it does not contain a tserevich active hydrogen-containing group (CH acidic compound) such as a hydroxyl group, amino group, or thiol group.

[0145] R 1 and R 2 Each of these groups is preferably an alkyl group having 1 to 10 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, or a butyl group.

[0146] R 1 and R 2 They may be the same or they may be different.

[0147] (n) In general formula (I), n is an integer greater than or equal to 2. In particular, n is preferably an integer between 2 and 6, more preferably an integer between 2 and 4, even more preferably 2 or 3, and especially preferably 2.

[0148] ≪Method for producing aspartate ester compounds represented by formula (I)≫ The aspartate ester compound represented by formula (I) can be produced by the method described in International Publication No. 2018 / 163959.

[0149] In the coating composition of this embodiment, the molar ratio NCO / NH is preferably 1.0 to 2.0, and more preferably 1.1 to 1.5. The molar ratio NCO / NH can be determined by the NCO content (%) of the polyisocyanate composition and the amine value of the aspartic acid ester compound.

[0150] ≪Additives≫ In this embodiment, the paint composition may contain an adsorbent as an additive component. Molecular sieves are suitably used as the adsorbent. Molecular sieves are natural or synthetic zeolites having a relatively high internal surface area and uniform pore size. Molecular sieves exhibit relatively high adsorption capacity and are used as adsorbents and water absorbents. The molecular sieves used in this embodiment preferably have a surface pore size of 2 to 10 angstroms, more preferably 2.5 to 4 angstroms, and even more preferably about 3 angstroms.

[0151] The adsorbent content is preferably 0.1 to 15% by weight, more preferably 0.5 to 8% by weight, and even more preferably 0.5 to 1.0% by weight, based on the total weight of the paint composition of this embodiment.

[0152] In this embodiment, the paint composition may include a matting agent as an additive component. The matting agent is not particularly limited, but examples include dry silica and precipitated silica. The dry silica is not particularly limited, but examples include ACEMATT 3400, ACEMATT 3300, and ACEMATT TS100 (each a trade name) (manufactured by Evonik Japan Co., Ltd.). The settling silica is not particularly limited, but examples include ACEMATT 3600, ACEMATT OK607(LC), ACEMATT OK390, ACEMATT OK900, ACEMATT OK520, ACEMATT OK500, ACEMATT OK412, ACEMATT HK390, ACEMATT 790, ACEMATT 82, ACEMATT HK520, ACEMATT HK400, ACEMATT 810, ACEMATT HK125, and ACEMATT HK440 (each a trade name) (manufactured by Evonik Japan Co., Ltd.). The matting agent may be surface-treated or untreated. These may be used individually or in combination of two or more types. The matting agent is not particularly limited, but among those mentioned above, the use of dry silica is especially preferred.

[0153] The matting agent content is preferably 3 to 20% by weight, based on the total solid weight of the paint composition of this embodiment.

[0154] The paint composition of this embodiment may further contain, if necessary, a polyvalent active hydrogen compound containing a polyol, melamine resin, epoxy resin, polyurethane resin, etc., as an additive component.

[0155] If the polyol in the paint composition of this embodiment has a carboxyl group, then an oxazoline group-containing compound and a carbodiimide group-containing compound can be added. If the polyol in the coating composition of this embodiment has a carbonyl group, a hydrazide group-containing compound or a semicarbazide group-containing compound may be added. These compounds may be added individually or in combination of two or more.

[0156] The paint composition of this embodiment preferably further contains a surface modifier as an additive component from the viewpoint of obtaining a paint film with excellent appearance. The type of surface modifier is not particularly limited, and examples include silicone-based, acrylic-based, and the like.

[0157] The surface modifier content is preferably 0.05% by mass or more and 5% by mass or less relative to the resin content of the paint composition. By having a surface modifier content above the lower limit mentioned above, a paint film with excellent appearance can be produced. Furthermore, by keeping the surface conditioning agent content below the above upper limit, the coating film exhibits better resistance to paint repellency, recoating properties, and stain resistance.

[0158] Commercially available silicone-based surface modifiers can be used, such as BYK-300, BYK-302, BYK-306, BYK-307, BYK-310, BYK-313, BYK-315N, BYK-320, BYK-322, BYK-323, BYK-325, BYK-326, BYK-330, BYK-331, BYK-333, BYK-342, BYK-370, BYK-375, BYK-377, BYK-378, BYK-3760 (manufactured by BYK); Disparon 1711EF, Disparon 1761, Disparon LS-001, Disparon LS-050, Disparon LS-280, Disparon LS-460, Disparon LS-480 (manufactured by Kusumoto Kasei Co., Ltd.); Tego Flow Examples include Tego Glide 425, Tego Glide 100, Tego Glide 110, Tego Glide 130, Tego Glide 406, Tego Glide 420, Tego Glide 432, Tego Glide 435, Tego Glide 440, Tego Glide 450, Tego Glide 482, Tego Glide 485, Tego Glide ZG400, Tego wet KL245, Tego wet 250, Tego wet 260, Tego wet 265, Tego wet 270, and Tego wet 280 (manufactured by Evonik Tego Chemie). These can be used individually or in combination of two or more types.

[0159] As acrylic surface modifiers, commercially available products can be used, such as BYK-350, BYK-354, BYK-355, BYK-356, BYK-358N, BYK-361N, BYK-392, BYK-394, BYK-3441 (manufactured by BYK); Disparon LF-1983, Disparon LF-1984, LF-1985, Disparon UVX-35, Disparon UVX-36 (manufactured by Kusumoto Chemical Co., Ltd.); Tego Flow 300, Tego Flow 370, Tego Flow ATF2, Tego Flow ZFS460 (manufactured by Evonik Tego Chemie). These may be used individually or in combination of two or more.

[0160] Other types of surface modifiers not listed above can be commercially available, such as BYK-399, BYK-3440, BYK-3550, BYK-3560, BYK-3565, BYK-SILCLEAN 3700, BYK-SILCLEAN 3701, BYKETOL-OK (manufactured by BYK); Disparon UVX-272, Disparon UVX-2285, Disparon LHP-810, Disparon NSH-8430HF, Disparon LHP-90, Disparon LHP-91, Disparon LHP-95, Disparon LHP-96 (manufactured by Kusumoto Kasei Co., Ltd.). These may be used individually or in combination of two or more types.

[0161] The paint composition of this embodiment may further contain an antifoaming agent, a foam suppressant, or a defoaming agent as an additive component, from the viewpoint of obtaining a paint film with excellent appearance. The types of antifoaming agents, foam suppressants, and defoaming agents are not particularly limited, and examples include silicone-based and polymer-based agents.

[0162] The content of defoaming agents, foam inhibitors, and defoaming agents is preferably 0.05% by mass or more and 5% by mass or less relative to the resin content of the paint composition. When the content of defoaming agents, foam inhibitors, and defoaming agents is above the lower limit, workability during compounding and stirring is improved, and a paint film with superior appearance can be produced. On the other hand, when the content of defoaming agents, foam inhibitors, and defoaming agents is below the upper limit, the paint film exhibits better resistance to paint repellency, recoating properties, and stain resistance.

[0163] Commercially available silicone-based defoaming agents, antifoaming agents, and defoaming agents can be used, such as BYK-063, BYK-065, BYK-066N, BYK-067A, BYK-077, BYK-081, BYK-1799 (manufactured by BYK); Disparon 1930N, Disparon 1934, Disparon SPX-44 (manufactured by Kusumoto Kasei Co., Ltd.); Tego Airex 900, Tego Airex 916, Tego Airex 931, Tego Airex 935, Tego Airex 962, Tego Airex 980, Tego Foamex N (manufactured by Evonik Tego Chemie). These may be used individually or in combination of two or more.

[0164] As polymer-based defoaming agents, antifoaming agents, and defoaming agents, commercially available products can be used, for example, BYK-051N, BYK-052N, BYK-054, BYK-055, BYK-057, BYK-354, BYK-392, BYK-1752, BYK-1788, BYK-1790, BYK-1791, BYK-1794 (manufactured by BYK); Disparon OX-60, Disparon OX-6140, Disparon OX-70, Disparon OX-710, Disparon OX-750HF, Disparon OX-77EF, Disparon OX-880EF, Disparon OX Examples include -881, Disparon OX-883HF, Disparon LAP-10, Disparon LAP-20, Disparon LAP-30, Disparon 1952, Disparon 1958, Disparon 1960, Disparon P-410EF, Disparon PD-7, Disparon P-420, Disparon P-450, Disparon OX-881, Disparon OX-883HF, Disparon LAP-10, Disparon P-425, Disparon UVX-188, Disparon UVX-189, Disparon UVX-190 (manufactured by Kusumoto Chemical Co., Ltd.); Tego Airex 910, Tego Airex 920, Tego Airex 936, Tego Airex 944, Tego Airex 955 (manufactured by Evonik Tego Chemie), etc. These can be used individually or in combination of two or more types.

[0165] Other types of defoaming agents, antifoaming agents, and defoaming agents not listed above can be commercially available, such as BYK-088, BYK-141 (manufactured by BYK); Disparon OX-66EF, Disparon OX-715 (manufactured by Kusumoto Chemical Co., Ltd.); Tego Airex 940, Tego Airex 945, Tego Airex 950, Tego Airex 986 (manufactured by Evonik Tego Chemie). These may be used individually or in combination of two or more types.

[0166] The paint composition of this embodiment may further contain a dispersant as an additive component, if necessary. Commercially available dispersants can be used, such as DESPERBYK-103, DESPERBYK-145, DESPERBYK-2155, and DESPERBYK-2159 (manufactured by BYK). These can be used individually, or two or more can be used in combination.

[0167] The additive components may also include pigments such as titanium dioxide, carbon black, indigo, quinacridone, and pearl mica; metal powder pigments such as aluminum; rheology control agents such as hydroxyethylcellulose, urea compounds, and microgels; curing accelerators such as tin compounds, zinc compounds, and amine compounds; and the aforementioned optional components such as ultraviolet absorbers, light stabilizers, and antioxidants.

[0168] The paint composition of this embodiment is preferably a paint for building structures. Examples of structural building coatings include coatings for building floors, walls, roofs, and building components, such as wind turbine or helicopter rotor blades, aircraft wings, or ship propellers.

[0169] The paint composition of the present invention makes it possible to produce a flexible coating film with a high crosslink density. Because such a coating film has particularly excellent weather resistance, it is suitable for heavy-duty corrosion protection coating of structures that require long-term weather resistance, such as bridges, highways, power transmission towers, and wind turbine power generation equipment (towers, blades, etc.), which are exposed to harsh environments such as wind, rain, snow, and temperature fluctuations. Furthermore, the paint composition of the present invention is suitably used to impart aesthetic properties, weather resistance, acid resistance, rust prevention, chipping resistance, adhesion, and the like. Furthermore, the coating composition of the present invention is also useful as an adhesive, a tack, an elastomer, a foam, a surface treatment agent, and the like.

[0170] <coating film> This embodiment is a coating film obtained by curing the paint composition of the above embodiment. The coating film of this embodiment is obtained by applying the above-mentioned coating composition using known methods such as roll coating, curtain flow coating, spray coating, bell coating, and electrostatic coating, and then curing it through a room temperature drying or baking process.

[0171] The coating film of this embodiment has excellent elongation. [Examples]

[0172] The present invention will be described more specifically below with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. The physical properties and evaluation of the polyisocyanate compositions in the examples and comparative examples were performed as follows. Unless otherwise specified, "parts" and "%" refer to "parts by mass" and "mass%", respectively.

[0173] <Synthesis Example 1-1> (A) Component (A1)1-1 was synthesized by the following method. A nitrogen atmosphere was created in a four-flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel. 100 parts HDI and 33.7 parts polycaprolactone triol with a number-average molecular weight of 850 and a hydroxyl value of 198 were charged, and the reactor temperature was maintained at 95°C for 90 minutes under stirring to carry out the urethane reaction. After cooling the reaction solution and filtering it, unreacted HDI was removed using a thin-film evaporator. Polyisocyanate (A1) 1-1 was obtained with an NCO content of 9.0% by mass, a viscosity of 4980 mPa.s at 25°C, a number-average molecular weight of 1520, an average number of isocyanate groups of 3.3, and an HDI monomer mass concentration of 0.2% by mass.

[0174] <Synthesis Example 1-2> (A) Component (A2)1-1 was synthesized by the following method. A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blower, and dropping funnel was placed under a nitrogen atmosphere. 100 parts HDI, 6.9 parts polycaprolactone triol with a number average molecular weight of 550 and a hydroxyl value of 305, and 12.8 parts polytetramethylene glycol with a number average molecular weight of 1000 and a hydroxyl value of 112 were charged into the flask. The reactor temperature was maintained at 90°C for 1 hour under stirring to carry out the urethane reaction. After cooling the reaction solution and filtering it, unreacted HDI was removed using a thin-film evaporator. Polyisocyanate (A2) 1-1 was obtained with an NCO content of 8.9%, a viscosity of 2740 mPa.s at 25°C, a number average molecular weight of 1570, an average number of isocyanate groups of 3.3, and an HDI monomer mass concentration of 0.2% by mass.

[0175] <Synthesis Example 1-3> Component (B), (B)1-1, was synthesized by the following method. A four-necked flask equipped with a stirrer, thermometer, and condenser was purged with nitrogen, and 2700 g of HDI and 210 g of 2-ethyl-1-hexanol were charged. The urethane reaction was carried out at 130°C for 1 hour under stirring. 0.54 g of a 20% solids mineral spirit solution of zirconyl 2-ethylhexanoate was added as an allophanate catalyst. When the refractive index of the reaction solution increased to 0.0055, 0.81 g of a 50% isobutanol solution of dodecyl phosphate (manufactured by Johoku Chemical Industry Co., Ltd., trade name "JP-512", diluted with isobutanol) (4.0 molars relative to the catalyst) was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed using a gravity-feed thin-film distillation apparatus, in two passes: the first at 160°C (27 Pa) and the second at 150°C (13 Pa). The obtained polyisocyanate was a clear liquid with a yield of 770 g, a viscosity of 110 mPa.s, and an NCO content of 17.2%. NMR analysis revealed a molar ratio of allophanate groups to isocyanurate groups of 97 / 3. The obtained polyisocyanate was designated (B)1-1.

[0176] <Examples 1-1 to 1-9, Comparative Examples 1-1 to 1-4> Using (A1)1-1, (A2)1-1, (B)1-1 and optional components, polyisocyanate compositions for Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-4 were obtained. As an optional component, the hindered amine compound Tinuvin 765 (manufactured by BASF Japan Ltd.) was used. The mixing ratio of each component, the individual properties of component (A), and the properties of the polyisocyanate composition are described in Tables 1-1 and 1-2 below.

[0177] [Table 1-1]

[0178] [Table 1-2]

[0179] In Tables 1-1 and 1-2, physical properties 1-1 to 1-5 refer to the following physical properties, respectively.

[0180] (Physical properties 1-1) NCO content (mass%) The NCO content (isocyanate content, mass%) of polyisocyanate was measured as follows: 1-3 g of polyisocyanate prepared in the example was weighed accurately (Wg) into an Erlenmeyer flask, and 20 mL of toluene was added to completely dissolve the polyisocyanate. Then, 10 mL of a 2 N di-n-butylamine toluene solution was added and thoroughly mixed, and the mixture was left at room temperature for 15 minutes. Furthermore, 70 mL of isopropyl alcohol was added to this solution and thoroughly mixed. This solution was titrated with a 1 N hydrochloric acid solution (factor F) using an indicator to obtain a titration value of V2 mL. A similar titration procedure was performed without polyisocyanate to obtain a titration value of V1 mL. From the obtained titration values ​​V2 mL and V1 mL, the NCO content of the polyisocyanate was calculated based on the following formula. NCO content=(V1-V2)×F×42 / (W×1000)×100

[0181] (Physical properties 1-2) Viscosity (mPa.s) The viscosity of polyisocyanate was measured at 25°C using an E-type viscometer (product name: RE-85R, manufactured by Toki Sangyo Co., Ltd.). A standard rotor (1°34' × R24) was used for the measurement. The rotation speed was set as follows: 100 r.pm (if less than 128 mPa.s) 50 r.pm (when the pressure is between 128 mPa.s and less than 256 mPa.s) 20 r.pm (when the pressure is between 256 mPa.s and less than 640 mPa.s) 10 r.pm (when the pressure is between 640 mPa.s and less than 1280 mPa.s) 5 r.pm (when the pressure is between 1280 mPa.s and less than 2560 mPa.s) 2.5 rpm (when the pressure is between 2560 mPa.s and less than 5184 mPa.s) 1.0 rpm (when the pressure is between 5184 mPa.s and less than 12960 mPa.s) 0.5 rpm (when pressure is between 12960 mPa.s and less than 25920 mPa.s)

[0182] (Physical properties 1-3) Number average molecular weight The number-average molecular weights of polyisocyanates, polyester polyols, and polyoxyalkylene polyols were determined using the number-average molecular weight relative to polystyrene, measured by gel permeation chromatography (hereinafter abbreviated as "GPC") using the following apparatus.

[0183] Equipment: Tosoh Corporation's "HLC-8120GPC" (product name) Column: 1 x "TSKgel SuperH1000" (product name) manufactured by Tosoh Corporation. "TSKgel SuperH2000" (product name) x 1 bottle "TSKgel SuperH3000" (product name) x 1 bottle Carrier: Tetrahydrofuran Detection method: Differential refractometer

[0184] (Physical properties 1-4) Average number of isocyanate groups The average number of isocyanate groups in polyisocyanates was calculated from (Property 1-1) NCO content and (Property 1-3) number-average molecular weight based on the following formula. Average number of isocyanate groups = [Number average molecular weight × NCO content (%)] / 4200

[0185] (Physical properties 1-5) Diisocyanate monomer mass concentration (mass%) The mass concentration of diisocyanate in polyisocyanates was determined as follows: First, a 20 mL sample vial was placed on a digital balance and approximately 1 g of the sample was weighed accurately. Next, 0.03-0.04 g of nitrobenzene (internal standard solution) was added and weighed accurately. Finally, approximately 9 mL of ethyl acetate was added, the lid was tightly closed, and the mixture was thoroughly mixed to prepare the sample. The prepared sample was analyzed by gas chromatography under the following conditions and quantified.

[0186] Equipment: “GC-8A” manufactured by SHIMADZU Column: Shinwa Chemical Co., Ltd. "Silicone OV-17" Column oven temperature: 120℃ Injection / Detector Temperature: 160℃

[0187] <Manufacturing of paint compositions> The main component is "FEISARATIC F420" (an aspartic acid ester compound, trade name of Zhuhai Feiyang Protech, amine value 201 mg KOH / resin g: in formula (I), X is a dicyclohexylmethylene group, R 1 is an ethyl group, R 2 (where is an ethyl group and n is 2) was used. In Tables 1-3 and 1-4, aspartic acid ester compounds are referred to as "PAE". As a curing agent, component (A) obtained above or a polyisocyanate composition was used. Specific materials are shown in Tables 1-3 and 1-4. The main component and the hardener were mixed in a ratio of NCO / NH = 1.1, and the paint solids content was adjusted with n-butyl acetate to 90% by mass to obtain paint compositions P1-1 to P1-6, P1-8, P1-9, P1-11 to P1-14, and paint compositions 1-1 to 1-6, 1-8, 1-9, and 1-11 to 1-14, respectively. The main component and the hardener were mixed in a ratio of NCO / NH = 1.1, and the paint solids content was adjusted with n-butyl acetate to 80% by mass to obtain paint compositions P1-7 and 1-7.

[0188] Furthermore, the additive components (adsorbents, matting agents) of the paint compositions listed in Tables 1-3 and 1-4 are the following materials. • Adsorbent: Molecular sieve, 3APowder (pore size approximately 3 angstroms) manufactured by Union Showa Co., Ltd. • Matting agent: ACEMATT 3400 manufactured by Evonik Japan.

[0189] In Tables 1-3 and 1-4, the percentage of additive components is expressed as a percentage of the total solid content of the paint composition.

[0190] [Table 1-3]

[0191] [Table 1-4]

[0192] ≪Evaluation of coating film properties≫ (Adjusting the whiteboard) A white board was prepared as the base material by first spray-painting an aluminum plate with commercially available solvent-based two-component acrylic urethane white enamel paint, setting it up, baking it at 80°C for 2 hours, curing it at room temperature for more than 2 weeks, and then sanding the surface with #1000 sandpaper until the gloss value at 60°C was 10% or less.

[0193] [Weather resistance] The obtained paint compositions were applied to white boards using an applicator to achieve a dry film thickness of 80 μm to 100 μm, and then dried at 23°C for 7 days to obtain a cured coating. Subsequently, the time required for the gloss retention rate to drop to 80% or less was evaluated using a DUE-PANEL light-controlled weather meter FDP manufactured by Suga Test Instruments Co., Ltd., under the conditions of JIS K5600-7-8.

[0194] [Elongation at break] Each of the obtained coating compositions was applied using an applicator to achieve a dry film thickness of 80 μm to 100 μm, and then dried at 23°C for 7 days to obtain cured films. The resulting cured film was measured for elongation at break using Tensilon, manufactured by Orientec, under the following measurement conditions. Measurement conditions Chuck spacing: 20mm Speed: 20mm / min Measurement temperature: 23℃, -20℃ Tables 1-5 and 1-6 show the elongation at break (in %) at 23°C and -20°C, respectively.

[0195] [Evaluation of growth rate] The elongation rate (in %) was calculated from the elongation at break of coating film 1-1 and coating film P1-1 at 23°C using the following formula. (Elongation at break of coating film 1-1 / Elongation at break of coating film P1-1) × 100

[0196] The elongation rate was similarly calculated for subsequent coating films 1-2 to 1-6, 1-8, 1-9, 1-11 to 1-15, P1-2 to P1-6, P1-8, P1-9, and P1-11 to P1-14.

[0197] The calculated growth rate was evaluated according to the following criteria. ○: Growth rate of 110% or more. △: Growth rate of 100% or more, but less than 110%. ×: Growth rate is less than 100%.

[0198] [Glossiness (60°)] The obtained coating compositions P1-7 and 1-7 were applied to ABS plates (black, Mitsubishi Plastics 802) using an applicator to achieve a dry film thickness of 80 μm to 100 μm, respectively. The films were then dried at 23°C for 7 days to obtain cured coating films P1-7 and 1-7. Subsequently, the gloss value at 60° was evaluated using a gloss meter (Haze-Gloss, BYK Gardner).

[0199] [Table 1-5]

[0200] [Table 1-6]

[0201] As shown in the results above, when the polyisocyanate composition of this embodiment (first embodiment) is used with a polyaspartic coating composition as a curing agent, it was confirmed that a coating film with excellent weather resistance and elongation can be obtained.

[0202] <Synthesis Example 2-1> (A) Component (A1)2-1 was synthesized by the following method. A nitrogen atmosphere was created in a four-flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel. 430.0 parts HDI, 73.9 parts polycaprolactone diol (number average molecular weight 400, hydroxyl value 283, composed of ε-caprolactone and 1,4-butanediol), and 73.9 parts polycaprolactone diol (number average molecular weight 830, hydroxyl value 131, composed of ε-caprolactone and diethylene glycol) were charged, and the reactor temperature was maintained at 100°C for 120 minutes under stirring to carry out the urethane reaction. After cooling the reaction solution and filtering it, unreacted HDI was removed using a thin-film evaporator. Polyisocyanate (A1)2-1 was obtained with an NCO content of 9.1% by mass, a viscosity of 1555 mPa.s at 25°C, a number average molecular weight of 1297, and an average number of isocyanate groups of 2.8.

[0203] <Synthesis Example 2-2> (A) Component (A1)2-2 was synthesized by the following method. A nitrogen atmosphere was created in a four-flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel. 450.0 parts HDI, 66.3 parts polycaprolactone diol (number average molecular weight 400, hydroxyl value 283, composed of ε-caprolactone and 1,4-butanediol), and 66.3 parts polyester diol (number average molecular weight 500, hydroxyl value 223, composed of adipic acid and 3-methyl-1,5-pentanediol) were charged. The reactor temperature was maintained at 100°C for 120 minutes under stirring to carry out the urethane reaction. After cooling the reaction solution and filtering it, unreacted HDI was removed using a thin-film evaporator. Polyisocyanate (A1)2-2 was obtained with an NCO content of 10.6% by mass, a viscosity of 1734 mPa.s at 25°C, a number average molecular weight of 1165, and an average number of isocyanate groups of 2.9.

[0204] <Synthesis Example 2-3> (A) Component (A1)2-3 was synthesized by the following method. A nitrogen atmosphere was created in a four-flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel. 420.0 parts HDI and 170.0 parts polycaprolactone diol, consisting of ε-caprolactone and diethylene glycol, with a number average molecular weight of 830 and a hydroxyl value of 131, were charged. The reactor temperature was maintained at 100°C for 120 minutes under stirring to carry out the urethane reaction. After cooling the reaction solution and filtering it, unreacted HDI was removed using a thin-film evaporator. Polyisocyanate (A1)2-3 was obtained with an NCO content of 7.0% by mass, a viscosity of 2009 mPa.s at 25°C, a number average molecular weight of 1623, and an average number of isocyanate groups of 2.7.

[0205] <Synthesis Example 2-4> (A) Component (A2)2-1 was synthesized by the following method. A nitrogen atmosphere was created in a four-flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel. 440.0 parts HDI, 74.0 parts polycaprolactone diol (composed of ε-caprolactone and 1,4-butanediol, with a number average molecular weight of 400 and a hydroxyl value of 283), and 74.0 parts polypropylene glycol (with a number average molecular weight of 1000 and a hydroxyl value of 111) were charged. The reactor temperature was maintained at 100°C for 120 minutes under stirring to carry out the urethane reaction. After cooling the reaction solution and filtering it, unreacted HDI was removed using a thin-film evaporator. Polyisocyanate (A2) 2-1 was obtained with an NCO content of 9.5% by mass, a viscosity of 1269 mPa.s at 25°C, a number average molecular weight of 1243, and an average number of isocyanate groups of 2.8.

[0206] <Synthesis Example 2-5> (A) Component (A2)2-2 was synthesized by the following method. A nitrogen atmosphere was created in a four-flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel. 470.0 parts HDI, 56.9 parts polycaprolactone diol (composed of ε-caprolactone and diethylene glycol, with a number average molecular weight of 550 and a hydroxyl value of 208), and 56.9 parts polypropylene glycol (with a number average molecular weight of 227 and a hydroxyl value of 494) were charged. The reactor temperature was maintained at 100°C for 120 minutes under stirring to carry out the urethane reaction. After cooling the reaction solution and filtering it, unreacted HDI was removed using a thin-film evaporator. Polyisocyanate (A2) 2-2 was obtained with an NCO content of 11.9% by mass, a viscosity of 1148 mPa.s at 25°C, a number average molecular weight of 942, and an average number of isocyanate groups of 2.7.

[0207] <Synthesis Example 2-6> (A) Component (A2)2-3 was synthesized by the following method. A nitrogen atmosphere was created in a four-flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel. 420.0 parts HDI, 68.9 parts polycaprolactone diol (composed of ε-caprolactone and 1,4-butanediol, with a number average molecular weight of 400 and a hydroxyl value of 283), and 68.9 parts polytetramethylene glycol (number average molecular weight of 655 and hydroxyl value of 172) were charged. The reactor temperature was maintained at 100°C for 120 minutes under stirring to carry out the urethane reaction. After cooling the reaction solution and filtering it, unreacted HDI was removed using a thin-film evaporator. Polyisocyanate (A2) 2-3 was obtained with an NCO content of 9.5% by mass, a viscosity of 1269 mPa.s at 25°C, a number average molecular weight of 1243, and an average number of isocyanate groups of 2.8.

[0208] <Synthesis Example 2-7> (A) Component (A1)2-4 was synthesized by the following method. A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen inlet tube, and a dropping funnel was filled with nitrogen gas. 430.0 parts of HDI, 64.9 parts of polycaprolactone diol composed of ε-caprolactone and 1,4-butanediol with a number average molecular weight of 400 and a hydroxyl value of 283, and 64.9 parts of polycaprolactone diol composed of ε-caprolactone and diethylene glycol with a number average molecular weight of 550 and a hydroxyl value of 208 were charged. The temperature inside the reactor was maintained at 100 °C for 120 minutes with stirring to conduct a urethanization reaction. After filtering the cooled reaction solution, unreacted HDI was removed using a thin-film evaporator. A polyisocyanate (A1)2-4 with an NCO content of 9.9% by mass, a viscosity of 1400 mPa·s at 25 °C, a number average molecular weight of 1143, and an average number of isocyanate groups of 2.7 was obtained.

[0209] <Synthesis Example 2-8> (A1)2-5, which is the (A) component, was synthesized by the following method. A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen inlet tube, and a dropping funnel was filled with nitrogen gas. 400.0 parts of HDI and 125.0 parts of polyester diol composed of sebacic acid and 3-methyl-1,5-pentanediol with a number average molecular weight of 490 and a hydroxyl value of 223 were charged. The temperature inside the reactor was maintained at 100 °C for 120 minutes with stirring to conduct a urethanization reaction. After filtering the cooled reaction solution, unreacted HDI was removed using a thin-film evaporator. A polyisocyanate (A1)2-5 with an NCO content of 9.8% by mass, a viscosity of 1755 mPa·s at 25 °C, a number average molecular weight of 1198, and an average number of isocyanate groups of 2.8 was obtained.

[0210] <Synthesis Example 2-9> (A1)2-6, which is the (A) component, was synthesized by the following method. The inside of a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen inlet tube, and a dropping funnel was made into a nitrogen atmosphere. 400.0 parts of HDI, a polyester diol with a number average molecular weight of 504, a hydroxyl value of 223, composed of adipic acid and 3-methyl-1,5-pentanediol, 127.0 parts were charged, and the temperature inside the reactor was maintained at 100 °C for 120 minutes with stirring, and a urethanization reaction occurred. After filtering the cooled reaction solution, unreacted HDI was removed using a thin-film evaporator. A polyisocyanate (A1)2-6 with an NCO content of 9.9% by mass, a viscosity of 2010 mPa·s at 25 °C, a number average molecular weight of 929, and an average number of isocyanate groups of 2.2 was obtained.

[0211] <Synthesis Example 2-10> (A1)2-7, which is the component (A), was synthesized by the following method. The inside of a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen inlet tube, and a dropping funnel was made into a nitrogen atmosphere. 400.0 parts of HDI, a polycaprolactone diol with a number average molecular weight of 550, a hydroxyl value of 208, composed of ε-caprolactone and diethylene glycol, 95.1 parts, 1,3-butanediol 10.6 parts were charged, and the temperature inside the reactor was maintained at 100 °C for 120 minutes with stirring, and a urethanization reaction occurred. After filtering the cooled reaction solution, unreacted HDI was removed using a thin-film evaporator. A polyisocyanate (A)2-7 with an NCO content of 11.0% by mass, a viscosity of 1511 mPa·s at 25 °C, a number average molecular weight of 976, and an average number of isocyanate groups of 2.6 was obtained.

[0212] <Synthesis Example 2-11> (A1)2-8, which is the component (A), was synthesized by the following method. A nitrogen atmosphere was created in a four-flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel. 400.0 parts HDI and 130.0 parts polycaprolactone diol, consisting of ε-caprolactone and diethylene glycol, with a number average molecular weight of 550 and a hydroxyl value of 208, were charged. The reactor temperature was maintained at 100°C for 120 minutes under stirring to carry out the urethane reaction. After cooling the reaction solution and filtering it, unreacted HDI was removed using a thin-film evaporator. Polyisocyanate (A1) 2-8 was obtained with an NCO content of 9.1% by mass, a viscosity of 1462 mPa.s at 25°C, a number average molecular weight of 1178, and an average number of isocyanate groups of 2.6.

[0213] <Synthesis Example 2-12> Component (B), (B)2-1, was synthesized by the following method. A four-necked flask equipped with a stirrer, thermometer, and condenser was purged with nitrogen, and 2700 g of HDI and 210 g of 2-ethyl-1-hexanol were charged. The urethane reaction was carried out at 130°C for 1 hour under stirring. 0.54 g of a 20% solids mineral spirit solution of zirconyl 2-ethylhexanoate was added as an allophanate catalyst. When the refractive index of the reaction solution increased to 0.0055, 0.81 g of a 50% isobutanol solution of dodecyl phosphate (manufactured by Johoku Chemical Industry Co., Ltd., trade name "JP-512", diluted with isobutanol) (4.0 molars relative to the catalyst) was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed using a gravity-feed thin-film distillation apparatus, in two passes: the first at 160°C (27 Pa) and the second at 150°C (13 Pa). The obtained polyisocyanate was a clear liquid with a yield of 770 g, a viscosity of 110 mPa·s, and an NCO content of 17.2%. NMR analysis revealed a molar ratio of allophanate groups to isocyanurate groups of 97 / 3. The obtained polyisocyanate was designated (B)2-1.

[0214] As a light stabilizer, we prepared Tinuvin 765 manufactured by BASF Japan Ltd.

[0215] <Examples 2-1 to 2-14, Comparative Examples 2-1 to 2-2> Using polyisocyanates (A1) 2-1 to (A1) 2-8, (A2) 2-1 to (A2) 2-3, (B) 2-1 and an optional light stabilizer, the polyisocyanate compositions of Examples 2-1 to 2-14 and Comparative Examples 2-1 to 2-2 were obtained. The mixing ratios of the respective components, the physical properties of the (A) component alone, and the physical properties of the polyisocyanate composition are described in Tables 2-1 to 2-3 below.

[0216]

Table 2-1

[0217]

Table 2-2

[0218]

Table 2-3

[0219] In Tables 2-1 to 2-3, Physical Properties 2-1 to 2-5 each mean the following physical properties.

[0220] (Physical Property 2-1) NCO content (mass %) Determined in the same manner as Physical Property 1-1.

[0221] (Physical Property 2-2) Viscosity (mPa·s) Measured in the same manner as Physical Property 1-2.

[0222] (Physical Property 2-3) Number average molecular weight The number average molecular weight of the polyisocyanate was determined in the same manner as Physical Property 1-3.

[0223] (Physical Property 2-4) Average number of isocyanate groups The average number of isocyanate groups of the polyisocyanate was determined in the same manner as Physical Property 1-4.

[0224] (Physical Property 2-5) Diisocyanate monomer mass concentration (mass %) The mass concentration of diisocyanate in polyisocyanate was determined using the same method as described in Physical Properties 1-5.

[0225] (Appearance evaluation) The immediately manufactured component (A), or the immediately manufactured polyisocyanate composition, was placed at a temperature of 23°C, and its transmittance was measured and evaluated according to the following criteria. A higher transmittance value indicates greater transparency. Equipment: JASCO V-650 UV-visible spectrophotometer manufactured by JASCO Corporation Measurement wavelength: 550nm Cell length: 20mm ○: 90% or more △: 60% or more but less than 90% ×: Less than 60%

[0226] <Manufacturing of paint compositions> The main ingredient used was "FEISARATIC F420" (an aspartic acid ester compound, trade name of Zhuhai Feiyang Protech, amine value 201 mg KOH / g resin). In Tables 2-4 and 2-5, the aspartic acid ester compound is referred to as "PAE". As a curing agent, component (A) obtained above or a polyisocyanate composition was used. Specific materials are shown in Tables 2-4 and 2-5. The main component and the hardener were mixed in a ratio of NCO / NH = 1.1, and the paint solids content was adjusted with n-butyl acetate to 90% by mass to obtain paint compositions P2-1 to P2-10, P2-12 to P2-18, and paint compositions 2-1 to 2-10, 2-12 to 2-18, respectively. The main component and the hardener were mixed in a ratio of NCO / NH = 1.1, and the mixture was adjusted with n-butyl acetate to a ratio of 80% by mass of paint solids to obtain paint composition P2-11 and paint composition 2-11.

[0227] Furthermore, the additive components (adsorbents, matting agents) of the paint compositions listed in Tables 2-4 and 2-5 are the following materials. • Adsorbent: Molecular sieve, 3APowder (pore size approximately 3 angstroms) manufactured by Union Showa Co., Ltd. • Matting agent: ACEMATT 3400 manufactured by Evonik Japan.

[0228] In Tables 2-4 and 2-5, the percentage of additive components is expressed as a percentage of the total solid weight of the paint composition.

[0229] [Table 2-4]

[0230] [Table 2-5]

[0231] <<Evaluation of coating film properties>> (Adjusting the whiteboard) A white board was prepared as the base material by first spray-painting an aluminum plate with commercially available solvent-based two-component acrylic urethane white enamel paint, setting it up, baking it at 80°C for 2 hours, curing it at room temperature for more than 2 weeks, and then sanding the surface with #1000 sandpaper until the gloss value at 60°C was 10% or less.

[0232] [Weather resistance] The obtained paint compositions were applied to white boards using an applicator to achieve a dry film thickness of 80 μm to 100 μm, and then dried at 23°C for 7 days to obtain a cured coating. Subsequently, the time required for the gloss retention rate to drop to 80% or less was evaluated using a DUE-PANEL light-controlled weather meter FDP manufactured by Suga Test Instruments Co., Ltd., under the conditions of JIS K5600-7-8.

[0233] [Elongation at break] Each of the obtained coating compositions was applied using an applicator to achieve a dry film thickness of 80 μm to 100 μm, and then dried at 23°C for 7 days to obtain cured films. The resulting cured film was measured for elongation at break using Tensilon, manufactured by Orientec, under the following measurement conditions. Measurement conditions Chuck spacing: 20mm Speed: 20mm / min Measurement temperature: 23℃, -20℃

[0234] Tables 2-6 to 2-8 show the elongation at break (in %) at 23°C and -20°C, respectively.

[0235] [Evaluation of growth rate] The elongation rate (in %) was calculated from the elongation at break of coating film 2-1 and coating film P2-1 at 23°C using the following formula. (Elongation at break of coating film 2-1 / Elongation at break of coating film P2-1) × 100

[0236] The elongation rates were similarly calculated for subsequent coating films 2-2 to 2-10, 2-12 to 2-18, and coating films P2-2 to P2-10, and P2-12 to P2-18.

[0237] The calculated growth rate was evaluated according to the following criteria. ○: Growth rate of 110% or more. △: Growth rate of 100% or more, but less than 110%. ×: Growth rate is less than 100%.

[0238] [Glossiness (60-degree gloss value)] The obtained coating compositions P2-11 and 2-11 were applied to ABS plates (black, Mitsubishi Plastics 802) using an applicator to achieve a dry film thickness of 80 μm to 100 μm, respectively. The films were then dried at 23°C for 7 days to obtain cured coating films, coating film P2-11 and coating film 2-11. Subsequently, the gloss value at 60°C was evaluated using a gloss meter (Haze-Gloss, BYK Gardner).

[0239] [Table 2-6]

[0240] [Table 2-7]

[0241] [Table 2-8]

[0242] As shown in the results above, the polyisocyanate composition of this embodiment (second embodiment) has an appearance with excellent transparency, and it was confirmed that when the polyaspartic coating composition is used as a curing agent, a coating film with excellent elongation and excellent break elongation at low temperatures can be obtained. [Industrial applicability]

[0243] The polyisocyanate composition of the present invention is useful as a curing agent for polyasparatic coating compositions.

Claims

1. A polyisocyanate composition comprising component (A) and component (B), The aforementioned component (A) is either component (A1) or component (A2), The aforementioned component (A1) is a polyisocyanate component obtained from at least one aliphatic diisocyanate and a polyester polyol having an average number of functional groups of 2 or 3. The aforementioned component (A2) is a polyisocyanate component obtained from at least one aliphatic diisocyanate, a polyester polyol having an average number of 2 or 3 functional groups, and a polyoxyalkylene polyol having an average number of 2 to 4 functional groups. The aforementioned component (B) is a polyisocyanate component obtained from at least one aliphatic diisocyanate and a monoalcohol having 1 to 20 carbon atoms, wherein the molar ratio of allophanate groups to isocyanurate groups (allophanate groups / isocyanurate groups) is 100 / 0 to 70 / 30. A polyisocyanate composition in which the ratio of component (A) to the total amount of component (B) is 60% by mass or more.

2. The polyisocyanate composition according to claim 1, wherein the average number of functional groups of the polyester polyol is 3.

3. The (A) component is the (A1) component, The polyisocyanate composition according to claim 1 or 2, wherein the number average molecular weight of the polyester polyol is 250 or more and 4000 or less.

4. The (A) component is the (A2) component, The number-average molecular weight of the polyester polyol is 250 or more and 4000 or less. The polyisocyanate composition according to claim 1 or 2, wherein the number-average molecular weight of the polyoxyalkylene polyol is 200 or more and 1500 or less.

5. The polyisocyanate composition according to claim 1, wherein the average number of functional groups of the polyester polyol is 2.

6. The (A) component is the (A1) component, The polyisocyanate composition according to claim 1 or 5, wherein the number average molecular weight of the polyester polyol is 250 or more and 4000 or less.

7. The (A) component is the (A2) component, The number-average molecular weight of the polyester polyol is 250 or more and 4000 or less. The polyisocyanate composition according to claim 1 or 5, wherein the number-average molecular weight of the polyoxyalkylene polyol is 100 or more and 2000 or less.

8. The polyisocyanate composition according to claim 1, comprising either an ultraviolet absorber or a light stabilizer, or both.

9. A paint composition comprising a main component and a hardener, The main component is an aspartate ester compound represented by the following formula (I): The coating composition wherein the curing agent is the polyisocyanate composition described in claim 1. 【Chemistry 1】 [In formula (I), X is an n-valent organic group obtained by removing the primary amino group of an n-valent polyamine, and R １ and R ２ [where n is the same or different organic group that is inert to the isocyanate group under the reaction conditions, and n is an integer of 2 or more.]

10. The paint composition according to claim 7, which is a paint for building structures.

11. A coating film obtained by curing the coating composition according to claim 7.

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