Polyisocyanate composition, coating 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 number of functional groups of 2 or 3; a polyisocyanate component (A2) obtained from a diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, a polyester polyol having an average number of functional groups of 2 or 3, and a polyoxyalkylene polyol having an average number of functional groups of 2 to 4; and a polyisocyanate component (B) which is obtained from a diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and a C1-20 monohydric alcohol, and which has a molar ratio (allophanate group / isocyanurate group) of 100 / 0 to 70 / 30. The ratio of the component (A1) or (A2) to the total amount of the component (A1) or (A2) and the component (B) is 60 mass% or more.

Description

Technical Field

[0001] The present invention relates to a polyisocyanate composition, a coating composition and a coating film.

[0002] 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 of which are incorporated herein by reference. Background Art

[0003] Aliphatic polyaspartic acid coating compositions within polyurea coating compositions are composed of an amino-containing aspartic acid ester compound and an isocyanate-containing aliphatic and / or alicyclic polyisocyanate composition. Aromatic polyurea coating compositions significantly reduce yellowing of the coating film due to UV exposure, a drawback of aromatic polyurea coating compositions, and have been used in a wide range of applications, including various coatings, flooring materials, and waterproofing materials.

[0004] Aspartic acid ester compounds have lower viscosities than the main polyols used in polyurethane coating compositions, significantly reducing the amount of diluent solvent in polyaspartic acid coating compositions. This allows for high-solids and solvent-free formulations. Furthermore, due to the rapid reactivity of the amino groups in aspartic acid ester compounds with the isocyanate groups of aliphatic and / or alicyclic polyisocyanates, polyaspartic acid coating compositions offer advantages over polyurethane coating compositions, such as faster curing speeds even at room temperature and superior mechanical strength.

[0005] For example, Patent Document 1 discloses a polyaspartic acid coating composition as an aliphatic polyurea coating composition comprising a polyamine component having an aspartic acid ester skeleton and containing secondary amino groups, and a polyisocyanate component containing isocyanate groups in an aliphatic polyisocyanate composition. This coating composition has a relatively long pot life and high coating film hardness, and therefore can be applied without the use of a high-pressure impingement mixing sprayer.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 3-43472 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] The polyaspartic acid coating composition disclosed in Patent Document 1 has room for further improvement in the elongation of a coating film obtained by using the polyaspartic acid coating composition.

[0011] In order to improve the elongation, a curing agent that can be suitably used in the polyaspartic acid coating composition is required.

[0012] In addition, depending on the composition of the curing agent, it may be prone to crystallization, which can cause the curing agent to become turbid. This makes it difficult to achieve uniform composition in the coating film when used in a polyaspartic acid coating composition. Therefore, a curing agent suitable for use in a polyaspartic acid coating composition is also required that does not easily become turbid.

[0013] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polyisocyanate composition that can be used as a curing agent suitable for a polyaspartic acid coating composition, 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.

[0014] Solutions for solving problems

[0015] The present invention includes the following aspects.

[0016] [1] A polyisocyanate composition comprising component (A) and component (B),

[0017] The component (A) is the component (A1) or the component (A2),

[0018] The 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;

[0019] The component (A2) is a polyisocyanate component comprising 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 or 3, and a polyoxyalkylene polyol having an average number of functional groups of 2 to 4;

[0020] The 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 monohydric alcohol having 1 to 20 carbon atoms, wherein the molar ratio of allophanate groups to isocyanurate groups (alophanate groups / isocyanurate groups) is 100 / 0 to 70 / 30;

[0021] The ratio of the component (A) to the total amount of the component (A) and the component (B) is 60% by mass or more.

[0022] [2] The polyisocyanate composition according to [1] above, wherein the average number of functional groups of the polyester polyol is 3.

[0023] [3] The polyisocyanate composition according to claim [2], wherein the polyester polyol has a number average molecular weight of 250 or more and 4000 or less,

[0024] The number average molecular weight of the polyoxyalkylene polyol is 200 or more and 1500 or less.

[0025] [4] The polyisocyanate composition according to [1] above, wherein the average number of functional groups of the polyester polyol is 2.

[0026] [5] The polyisocyanate composition according to [4], wherein the number average molecular weight of the polyester polyol is 250 or more and 4000 or less,

[0027] The number average molecular weight of the polyoxyalkylene polyol is 100 or more and 2000 or less.

[0028] [6] The polyisocyanate composition according to any one of [1] to [5], comprising one or both of an ultraviolet absorber and a light stabilizer.

[0029] [7] A coating composition comprising 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 described in any one of [1] to [6].

[0030]

[0031] [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 inactive towards isocyanate groups under the reaction conditions, and n is an integer greater than 2.]

[0032] [8] The coating composition according to [7], which is a coating for building structures.

[0033] [9] A coating film formed by curing the coating composition described in [7].

[0034] Effects of the Invention

[0035] According to the present invention, there are provided a polyisocyanate composition that can be used as a curing agent suitable for a polyaspartic acid coating composition and can impart excellent weather resistance, elongation, and / or low-temperature elongation to the resulting coating film, as well as a coating composition and a coating film using the polyisocyanate composition. DETAILED DESCRIPTION

[0036] Hereinafter, a mode for implementing the present invention (hereinafter referred to as "this embodiment") will be described in detail. The present invention is not limited to the following embodiment. The present invention can be implemented by appropriately modifying the present invention within the scope of its gist.

[0037] In addition, in this specification, "polyol" refers to a compound having two or more hydroxyl groups (-OH).

[0038] In this specification, "polyisocyanate" refers to a reaction product (polymer) in which a plurality of monomeric compounds (monomers) having one or more isocyanate groups (-NCO) are bonded together.

[0039] <Polyisocyanate composition>

[0040] This embodiment is a polyisocyanate composition comprising the components (A) and (B).

[0041] The component (A) is the component (A1) or the component (A2),

[0042] The 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;

[0043] The component (A2) is a polyisocyanate component comprising 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 or 3, and a polyoxyalkylene polyol having an average number of functional groups of 2 to 4;

[0044] The 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 monohydric alcohol having 1 to 20 carbon atoms, wherein the molar ratio of allophanate groups to isocyanurate groups (alophanate groups / isocyanurate groups) is 100 / 0 to 70 / 30;

[0045] The ratio of the component (A) to the total amount of the component (A) and the component (B) is 60% by mass or more.

[0046] The polyisocyanate composition of the present embodiment can be suitably used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main component.

[0047] <First embodiment>

[0048] "(A)Component"

[0049] (A) Component is (A1) component or (A2) component.

[0050] ·(A1)Ingredients

[0051] In the first embodiment of the present embodiment, the 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.

[0052] Diisocyanate

[0053] 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.

[0054] Aliphatic diisocyanate refers to a compound having only an aliphatic group in the molecule. As the aliphatic diisocyanate used in the present embodiment, it is not particularly limited, and preferably an aliphatic diisocyanate having a carbon number of more than 4 and less than 30, for example, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (hereinafter referred to as "HDI"), 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, and lysine diisocyanate can be listed. Among them, from the ease of industrial acquisition, HDI is more preferred. The aliphatic diisocyanate shown above can be used alone or in combination of two or more.

[0055] Alicyclic diisocyanate refers to a compound having a cyclic aliphatic group in the molecule. As the alicyclic diisocyanate used in the present embodiment, there is no particular limitation, and preferably an alicyclic diisocyanate having a carbon number of 8 or more and 30 or less, for example, isophorone diisocyanate (hereinafter referred to as "IPDI"), 1,3-bis (isocyanatomethyl) -cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, norbornene diisocyanate and hydrogenated xylylene diisocyanate can be listed. Among them, IPDI is more preferred from the perspective of weather resistance and ease of industrial acquisition. The alicyclic diisocyanate shown above can be used alone or in combination of two or more.

[0056] As the diisocyanate monomer, one or more aliphatic diisocyanates and one or more alicyclic diisocyanates may be used in combination.

[0057] Polyester polyols with an average functional group number of 3

[0058] The polyester polyol having an average number of functional groups of 3 is a trivalent polyol containing a repeating unit represented by -O(CH2)5CO-, and can be derived from a trivalent alcohol and ε-caprolactone, etc. Furthermore, there are no particular limitations, and for example, ε-caprolactone, etc. can be obtained by ring-opening polymerization using a trivalent alcohol as an initiator in the presence of a catalyst.

[0059] 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.

[0060] The polyester polyol having an average number of functional groups of 3 can be obtained by condensing a dibasic acid alone or a mixture of two or more dibasic acids with a polyol alone or a mixture of two or more polyols.

[0061] Examples of the dibasic acid 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, suberic acid, azelaic acid, sebacic acid, decanedioic acid, itaconic acid, itaconic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, tetrahydrophthalic acid, and carboxylic acids such as tetrahydrophthalic acid.

[0062] Examples of the polyol include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, 2-ethyl-1,3-hexanediol, trimethylolpropane, glycerol, pentaerythritol, 2-hydroxymethylpropanediol, ethoxylated trimethylolpropane, 1,3-propanediol, pentane-1,5-diol, heptane-1,7-diol, octane-1,8-diol, nonane-1,9-diol, decane-1,10-diol, and dodecane-1,12-diol. -diol, cyclohexane-1,4-dimethanol, 4,4'-(1-methylethylene)bicyclohexanol, 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, 2-methyl-1,3-propanediol, etc.

[0063] When a polyisocyanate composition using a polyester polyol having an average functional group number of 3 is used as a curing agent and an aspartic acid ester compound is used as a main agent, the compatibility between the main agent and the curing agent becomes high. Therefore, the polyisocyanate composition of this embodiment can be suitably used as a curing agent for a polyaspartic acid coating composition using an aspartic acid ester compound as a main agent.

[0064] Furthermore, when a polyester polyol having an average number of functional groups of 3 is used, a coating film can be produced that exhibits high flexibility due to three-dimensional crosslinking, has high coating film elongation, and is excellent in weather resistance.

[0065] The number average molecular weight of the polyester polyol having an average number of functional groups of 3 is preferably 250 to 4000, more preferably 250 to 1500, further preferably 250 to 1000, particularly preferably 300 to 1000, and most preferably 500 to 900.

[0066] When the number average molecular weight of the polyester polyol having an average number of functional groups of 3 is equal to or greater than the above lower limit, a coating film having high elongation can be produced when used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main component.

[0067] When the number average molecular weight of the polyester polyol having an average number of functional groups of 3 is below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main agent, the coating composition tends to maintain a low viscosity. Therefore, the polyisocyanate composition of this embodiment can be suitably used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main agent.

[0068] The number average molecular weight of the polyester polyol having an average number of functional groups of 3 is a polystyrene-based number average molecular weight measured by gel permeation chromatography (hereinafter abbreviated as "GPC") and can be measured by the method described in the Examples below.

[0069] As the initiator, trimethylolpropane, glycerin, or the like, which is a trihydric alcohol, can be used.

[0070] As the catalyst, preferably used are organic titanium 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 the polyester polyol having an average number of functional groups of 3, the catalyst is preferably a tin compound.

[0071] Ring-opening polymerization of ε-caprolactone and the like is preferably carried out under a nitrogen atmosphere. ε-caprolactone and the aforementioned initiator are charged in a molar ratio set to achieve a predetermined molecular weight. Furthermore, a catalyst is added in an amount of 0.1 to 100 ppm by mass relative to the ε-caprolactone. The reaction is then carried out at a temperature of 150°C to 200°C for 4 to 10 hours. However, it is important to control the reaction so that the caprolactone dimer content is 100 to 1000 ppm by mass at the end of the reaction. If necessary, caprolactone dimers can be removed from the resulting polycaprolactone polyol by extraction, distillation, or other methods.

[0072] In addition to ε-caprolactone, a portion of other cyclic lactones such as trimethylcaprolactone and valerolactone may be mixed.

[0073] The polyester polyol having an average number of functional groups of 3 can be produced, for example, by subjecting a single dibasic acid or a mixture of dibasic acids to a known condensation reaction with a single polyol or a mixture of polyols. For example, the reaction can be carried out by combining the dibasic acid component and the polyol component and then heating them at approximately 160 to 220°C.

[0074] In the component (A1), the amount of the polyester polyol having an average functional group number of 3 is preferably, for example, 10 to 80 parts by mass, and more preferably 30 to 45 parts by mass, per 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

[0075] (A2) ingredient

[0076] In the first embodiment of the present embodiment, the 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 functional group number of 3, and a polyoxyalkylene polyol having an average functional group number of 2 to 4.

[0077] Diisocyanate

[0078] As the diisocyanate, the same monomer as the diisocyanate in the component (A1) can be used.

[0079] Polyester polyols with an average functional group number of 3

[0080] As the polyester polyol having an average number of functional groups of 3, the same polymer as the polyester polyol having an average number of functional groups of 3 in the component (A1) can be used.

[0081] Polyoxyalkylene polyols

[0082] Polyoxyalkylene polyols are polyols containing -O(CH2) m A polyol having a valence of 2 or more and 4 or less, and having a repeating unit represented by - (wherein m is an integer of 2 or more, preferably an integer of 3 to 5, and more preferably 3 or 4) can be derived from a valence of 2 or more and 4 or less alcohol and ethylene oxide, propylene oxide, tetrahydrofuran, or the like. Furthermore, there are no particular limitations, and for example, ethylene oxide, propylene oxide, tetrahydrofuran, or the like can be obtained by cationic polymerization using a valence of 2 or more and 4 or less alcohol as an initiator in the presence of a catalyst.

[0083] The polyoxyalkylene polyol is preferably polytetramethylene glycol.

[0084] The number average molecular weight of the polyoxyalkylene polyol is preferably 200 or more and 1500 or less, and more preferably 200 or more and 1000 or less.

[0085] When the number average molecular weight of the polyoxyalkylene polyol is at least the above lower limit, when the polyoxyalkylene polyol is used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main component, a coating film having high elongation can be produced.

[0086] When the number average molecular weight of the polyoxyalkylene polyol is below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main agent, the coating composition tends to maintain a low viscosity. Therefore, the polyisocyanate composition of the present embodiment can be suitably used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main agent.

[0087] The number average molecular weight of the polyoxyalkylene polyol is a number average molecular weight based on polystyrene standards measured by GPC, and can be measured by the method described in Examples below.

[0088] As the initiator, diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, and neopentyl glycol, triols such as trimethylolpropane and glycerin, and tetraols such as pentaerythritol can be used.

[0089] As the catalyst, a strong basic catalyst such as a hydroxide of lithium, sodium, potassium, or the like, an alkoxide, or an alkylamine can be used.

[0090] Cationic polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc. is preferably carried out under a nitrogen atmosphere by charging ethylene oxide, propylene oxide, tetrahydrofuran, etc. and the above-mentioned initiator at a molar ratio set to a ratio to achieve a predetermined molecular weight, further adding a catalyst in an amount of 0.1 mass ppm to 100 mass ppm relative to the ethylene oxide, propylene oxide, tetrahydrofuran, etc., and reacting at a temperature of 150° C. to 200° C. for 4 hours to 10 hours.

[0091] In the component (A2), the amount of the polyester polyol having an average functionality of 3 is preferably, for example, 1 to 50 parts by mass, and more preferably 5 to 10 parts by mass, per 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

[0092] In the component (A2), the amount of the polyoxyalkylene polyol having an average number of functional groups of 2 to 4 is preferably, for example, 1 to 50 parts by mass, and more preferably 10 to 20 parts by mass, per 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

[0093] 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 relative to the total amount (100% by mass) of component (A). The NCO content is more preferably 6% by mass or more, and further preferably 7% by mass or more. The NCO content is more preferably 25% by mass or less, further preferably 20% by mass or less, and further preferably 10% by mass or less. When the NCO content is above the above lower limit, it is easier to maintain the drying and curing properties of the coating film. When the NCO content is below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition, it is easy to improve the scratch resistance of the resulting coating film. The NCO content of component (A) can be measured by the method described in the examples described later.

[0094] The viscosity of component (A) at 25°C is preferably 500 mPa.s or more and 50,000 mPa.s or less. The viscosity is more preferably 1,000 mPa.s or more, further preferably 1,500 mPa.s or more, and particularly preferably 2,000 mPa.s or more. The viscosity is more preferably 40,000 mPa.s or less, further preferably 30,000 mPa.s or less, further preferably 25,000 mPa.s or less, and particularly preferably 5,000 mPa.s or less. If the viscosity is above the lower limit, it is easy to improve the scratch resistance of the resulting coating film when used as a curing agent for a polyaspartic acid coating composition. When the viscosity is below the upper limit, it is easier to maintain drying properties. The viscosity of component (A) can be measured at 25°C using an E-type viscometer and measured by the method described in the examples described later.

[0095] The number average molecular weight of component (A) is preferably 250 or more and 4000 or less. The number average molecular weight is more preferably 300 or more and 3000 or less, further preferably 300 or more and 2500 or less, further preferably 400 or more and 2000 or less, and particularly preferably 500 or more and 1700 or less. By making the number average molecular weight above the above lower limit, when used as a curing agent for a polyaspartic acid coating composition, it is easy to improve the scratch resistance of the obtained coating film. By making the number average molecular weight below the above upper limit, it is easier to maintain dryness. The number average molecular weight of component (A) is a number average molecular weight based on a polystyrene benchmark measured by GPC, and can be measured by the method described in the examples described below.

[0096] The average number of isocyanate groups of component (A) is preferably 2.0 or more and 10.0 or less. The average number of isocyanate groups is more preferably 2.2 or more, further preferably 2.4 or more, particularly preferably 2.6 or more, and particularly more preferably 2.8 or more. The average number of isocyanate groups is more preferably 9.0 or less, further preferably 8.0 or less, further preferably 7.0 or less, and particularly preferably 4.0 or less. By making the average number of isocyanate groups above the above lower limit, it is easier to maintain dryness. By making the average number of isocyanate groups below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition, it is easy to improve the scratch resistance and weather resistance of the obtained coating film. The average number of isocyanate groups of component (A) can be measured by the method described in the examples described later.

[0097] The mass concentration of the diisocyanate monomer in the component (A) is preferably 1.0 mass % or less, more preferably 0.5 mass % or less, and even more preferably 0.3 mass % or less, relative to the total amount (100 mass %) of the component (A).

[0098] When the diisocyanate monomer mass concentration is below the above upper limit, the drying property can be maintained more easily. The diisocyanate monomer mass concentration of the component (A) can be measured by gas chromatography analysis according to the method described in the Examples below.

[0099] <<Method for producing component (A)>>

[0100] The component (A) can be produced by the method described in International Publication No. 2018 / 163959.

[0101] Specifically, component (A) can be obtained by reacting the isocyanate groups of a diisocyanate monomer with the hydroxyl groups of a polyester polyol and / or a polyoxyalkylene polyol in the presence of an excess of a diisocyanate monomer to form urethane groups, and then removing the unreacted diisocyanate monomer.

[0102] 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 functional groups of 3 to 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, carrying out a urethanization reaction, and then removing unreacted diisocyanate monomers.

[0103] Component (A2) can be obtained, for example, by adding 1 to 50 parts by mass, preferably 5 to 10 parts by mass, of a polyester polyol having an average number of functional groups of 3, and 1 to 50 parts by mass, preferably 10 to 20 parts by mass, of a polyoxyalkylene polyol having an average number of functional groups of 2 to 4, to 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, carrying out a urethanization reaction, and then removing the unreacted diisocyanate monomer.

[0104] Component (B)

[0105] The component (B) in the first embodiment of the present embodiment is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and a monohydric alcohol having 1 to 20 carbon atoms, and having a molar ratio of allophanate groups to isocyanurate groups (alophanate groups / isocyanurate groups) of 100 / 0 to 70 / 30.

[0106] Diisocyanate

[0107] The description of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates in the component (B) is the same as the description of the diisocyanate monomer in the component (A) described above.

[0108] Monohydric alcohols with 1 to 20 carbon atoms

[0109] The number of carbon atoms in a monohydric alcohol 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 monohydric alcohol having 1 to 20 carbon atoms is preferably 16 or less, more preferably 12 or less, and particularly preferably 9 or less. A single monohydric alcohol may be used, or a mixture of two or more may be used. The monohydric alcohol used in the present invention may contain an ether group, an ester group, or a carbonyl group in the molecule, and is preferably a monohydric alcohol formed from a saturated hydrocarbon group. Furthermore, a branched monohydric alcohol is more preferred.

[0110] Examples of such monohydric alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, isopentanol, 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.

[0111] Among them, isobutanol, n-butanol, isopentanol, 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, isopentanol, 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 them, 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.

[0112] The molar ratio of allophanate groups to isocyanurate groups in component (B) is 100 / 0 to 70 / 30, preferably 99 / 1 to 70 / 30. The molar ratio of allophanate groups to isocyanurate groups is preferably 98 / 2 or less, more preferably 97 / 3 or less. The molar ratio of allophanate groups to isocyanurate groups is preferably 74 / 26 or more, more preferably 77 / 23 or more, more preferably 80 / 20 or more, and particularly preferably 90 / 10 or more. When the molar ratio of allophanate groups to isocyanurate groups falls within the above range, the curing property becomes sufficient.

[0113] It should be noted that the molar ratio of allophanate groups to isocyanurate groups can be 1 The following is shown by H-NMR. 1 This is an example of a method for measuring a polyisocyanate composition using hexamethylene diisocyanate and an isocyanate prepolymer obtained therefrom as raw materials by H-NMR.

[0114] 1 H-NMR measurement method example

[0115] Component (B) was dissolved in deuterated chloroform at a concentration of 10% by mass (0.03% by mass of tetramethylsilane was added relative to component (B)). The chemical shift standard was set to 0 ppm for the hydrogen signal of tetramethylsilane. 1 H-NMR measurement was performed to measure the area ratio of the signal of the hydrogen atoms bonded to the nitrogen of the allophanate group (1 mol of hydrogen atoms relative to 1 mol of the allophanate group) near 8.5 ppm and the signal of the hydrogen atoms of the methylene group adjacent to the isocyanurate group (6 mol of hydrogen atoms relative to 1 mol of the isocyanurate group) near 3.85 ppm.

[0116] Allophanate group / isocyanurate group = (signal area near 8.5 ppm) / (signal area near 3.85 ppm / 6)

[0117] In addition, since the uretdione compound is easily dissociated by heat or the like to produce HDI, it is preferable to reduce the content of the uretdione compound.

[0118] The content of uretdione is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less relative to the polyisocyanate composition. The determination of the content of uretdione can be obtained by measuring the ratio of the area of the peak of about molecular weight 336 of gel permeation chromatography (hereinafter referred to as GPC) with a differential refractometer. In the case where there is a peak that becomes an obstacle to determination near the peak of about molecular weight 336, it can also be obtained as follows: using FT-IR, by using an internal standard quantitative 1770cm -1 The peak height of the uretdione group is about 1720 cm -1 A method of measuring the ratio of the peak heights of the allophanate group.

[0119] The following describes the measurement method of GPC. The measured value of the molecular weight of 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, outflow rate 0.6 ml / min., column temperature 40°C). The GPC calibration curve was prepared using polystyrenes with molecular weights 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), 5,040 to 35,125 (Mp = 2,050, Mw / Mn = 1.05, manufactured by GL Science Co., Ltd.), trimers to heptamers of isocyanurate forms 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 = 1,176), and HDI (molecular weight = 168) as standards.

[0120] The amount of urethane 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.

[0121] Furthermore, the solubility of biuret bodies and other diisocyanate polymers is also reduced, so a large content is not preferred. The amount of biuret bodies 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.

[0122] The component (B) preferably contains, for example, 1 to 20 parts by mass, preferably 1 to 10 parts by mass, of a monohydric alcohol having 1 to 20 carbon atoms per 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

[0123] The isocyanate group content (hereinafter referred to as NCO content) of component (B) is 10 to 22% by mass, preferably 13 to 21% by mass, and more preferably 16 to 20% by mass, in a state substantially free of solvent and diisocyanate. Within the range of 10 to 22% by mass, compatibility with component (A) is improved, and a polyisocyanate composition having sufficient crosslinking properties can be obtained.

[0124] The viscosity of component (B) is preferably 50 to 500 mPa·s in a state in which no solvent or diisocyanate is substantially contained. The viscosity of component (B) is preferably 75 mPa·s or more, more preferably 90 mPa·s or more. The viscosity of component (B) is preferably 450 mPa·s or less, more preferably 400 mPa·s or less, further preferably 350 mPa·s or less, and particularly preferably 300 mPa·s or less. When the viscosity of component (B) is 50 mPa·s or more, a polyisocyanate composition having sufficient crosslinking properties can be obtained. When the viscosity of component (B) is 500 mPa·s or less, a polyisocyanate composition having reduced volatile organic compound (VOC) components can be obtained.

[0125] The viscosity of the component (B) can be measured at 25° C. using an E-type viscometer, and can be measured by the method described in Examples below.

[0126] 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 greater. The average number of isocyanate groups in component (B) is preferably 2.4 or less, more preferably 2.3 or less. When the average number of isocyanate groups and the average number of functional groups are within the range of 2.0 to 2.5, the curing properties of the resulting coating film are improved.

[0127] The average number of isocyanate groups can be calculated by the following formula.

[0128] Average number of isocyanate groups = [number average molecular weight × NCO content (%)] / 4200

[0129] The number average molecular weight can be determined by GPC measurement.

[0130] <<Method for producing component (B)>>

[0131] Component (B) can be obtained, for example, by subjecting 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates to a urethanization reaction with 1 to 20 parts by mass, preferably 1 to 10 parts by mass, of a monohydric alcohol having 1 to 20 carbon atoms; then, an allophanation catalyst is added to carry out an allophanation reaction; then, the reaction is terminated and the unreacted diisocyanate monomer is removed.

[0132] 《Compounding ratio of component (A) and component (B)》

[0133] In the present embodiment, the ratio of the component (A) to the total amount of the component (A) and the component (B) is 60% by mass or more.

[0134] In the present 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, further preferably 90% by mass or less, and particularly preferably 80% by mass or less.

[0135] In the present embodiment, the proportion of component (A) relative 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 further preferably 60% by mass or more and 80% by mass or less.

[0136] When the content of the component (A) is within the above range, a polyisocyanate composition can be obtained that can be used as a curing agent suitably for a polyaspartic acid coating composition and can impart excellent elongation to the resulting coating film.

[0137] When the content of the component (A) is at least the above lower limit, high flexibility is exhibited by three-dimensional crosslinking, and a coating film having high elongation can be produced.

[0138] When the content of component (A) is below the upper limit, component (B) disrupts the orientation of component (A1) or component (A2). As a result, the crystallization of component (A) is disrupted, and a coating film with high elongation can be produced.

[0139] 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 the components (A) and (B). The NCO content is more preferably 6% by mass or more, and further preferably 7% by mass or more. The NCO content is more preferably 30% by mass or less, further preferably 25% by mass or less, further preferably 15% by mass or less, and particularly preferably 13% by mass or less. When the NCO content is above the above lower limit, when used as a curing agent for a polyaspartic acid coating composition, it is easier to maintain the drying and curing properties of the obtained coating film. When the NCO content is below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition, a coating film with high elongation can be manufactured. The NCO content can be measured by the method described in the embodiments described below.

[0140] The viscosity of the polyisocyanate composition at 25°C is preferably 500 mPa·s or more and 4000 mPa·s or less. The viscosity is more preferably 3000 mPa·s or less, further preferably 2000 mPa·s or less, particularly preferably 1350 mPa·s or less, and more preferably 1000 mPa·s or more.

[0141] When the viscosity is at least the lower limit, a coating film with high elongation can be produced when used as a curing agent for a polyaspartic acid coating composition. When the viscosity is at most the upper limit, weather resistance can be more easily maintained.

[0142] The viscosity of the polyisocyanate composition can be measured at 25° C. using an E-type viscometer, and can be measured by the method described in Examples below.

[0143] The average number of isocyanate groups in the polyisocyanate composition is preferably 1.8 or more and 10.0 or less. The average number of isocyanate groups is more preferably 2.0 or more, particularly preferably 2.8 or more. The average number of isocyanate groups is more preferably 10.0 or less, further preferably 5.0 or less, particularly preferably 3.5 or less. By setting the average number of isocyanate groups to be above the above lower limit, when used as a curing agent for a polyaspartic acid coating composition, the weather resistance of the resulting coating film can be easily maintained. By setting the average number of isocyanate groups to be below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition, a coating film with high elongation can be produced.

[0144] The average number of isocyanate groups in the polyisocyanate composition can be measured by the method described in Examples below.

[0145] Any Ingredient

[0146] In the present embodiment, the polyisocyanate composition preferably contains either or both of an ultraviolet absorber and a light stabilizer.

[0147] The ultraviolet absorber is not particularly limited, and examples thereof include benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, and cyanoacrylate-based compounds.

[0148] The benzotriazole-based compound is not particularly limited, and examples thereof include Tinuvin P·PS·99-2·213·234·326·329·360·384-2·571·900·928·970·1130 (manufactured by BASF Japan Co., Ltd.), Adekastab 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 Taiwan Everlight Chemical Industry Co., Ltd.).

[0149] The triazine compound is not particularly limited, and examples thereof include Tinuvin 400, 400-DW, 405, 460, 477, 479, 479-DW, 1577ED, and 1600 (manufactured by BASF Japan Co., Ltd.) and EVERSORB 40, 41FD, and 45 (manufactured by Taiwan Everlight Chemical Co., Ltd.).

[0150] The benzophenone compound is not particularly limited, and examples thereof include Chimassorb 81·81FL (manufactured by BASF Japan Co., Ltd.), Uvinul 3049·3050 (manufactured by BASF Japan Co., Ltd.), Adekastab 1413 (manufactured by ADEKA Co., Ltd.), and EVERSORB 10·11·12·51·52 (manufactured by Taiwan Everlight Chemical Co., Ltd.).

[0151] The cyanoacrylate compound is not particularly limited, and examples thereof include Uvinul 3030FF, 3035, and 3039 (manufactured by BASF Japan Co., Ltd.).

[0152] From the viewpoint of maintaining weather resistance over a long period of time, benzotriazole-based compounds, triazine-based compounds, and benzophenone-based compounds are preferred, and benzotriazole-based compounds and triazine-based compounds are more preferred.

[0153] The light stabilizer is not particularly limited, and specific examples thereof include hindered amine compounds.

[0154] The hindered amine compound is not particularly limited, and examples thereof include Tinuvin 111FDL·123·123-DW·PA144·152·249·292·783FDL·765 (manufactured by BASF Japan Co., Ltd.), Adekastab LA-52·57·63P·68·72·77Y·77G·81·402AF (manufactured by ADEKA Co., Ltd.), and EVERSORB 60·61·90·91FD·93·94FD·95·765·S02 (manufactured by Taiwan Everlight Chemical Industry Co., Ltd.).

[0155] When the polyisocyanate composition contains either or both of the ultraviolet absorber and the light stabilizer, the amount thereof added is, for example, 10 ppm by mass or more and 15,000 ppm by mass or less.

[0156] In this embodiment, the polyisocyanate composition may contain an antioxidant. Examples of the hindered phenol-based antioxidant include, but are not particularly limited to, butylated hydroxytoluene (hereinafter sometimes referred to as "BHT"), Irganox 1010 (trade name), Irganox 1135 (trade name), Irganox 1330 (trade name), Irganox 3114 (trade name), Irganox 565 (trade name), and Irganox 1520L (trade name) (each manufactured by BASF), Adekastab AO-20 (trade name), Adekastab AO-30 (trade name), Adekastab AO-50 (trade name), Adekastab AO-60 (trade name), and Adekastab AO-80 (trade name) (each manufactured by ADEKA Co., Ltd.).

[0157] <Second embodiment>

[0158] In the second embodiment of the present embodiment, description of the same configuration as that of the first embodiment may be omitted.

[0159] "(A)Component"

[0160] (A) Component is (A1) component or (A2) component.

[0161] ·(A1)Ingredients

[0162] The 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 functional group number of 2.

[0163] Diisocyanate

[0164] The diisocyanate used in the second embodiment is selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

[0165] As the aliphatic diisocyanate and the alicyclic diisocyanate, the monomers described in the first embodiment can be used in the same manner, but HDI is preferably used.

[0166] Polyester polyols with an average functional group number of 2

[0167] The polyester polyol having an average number of functional groups of 2 is a divalent polyol containing a repeating unit represented by -O(CH2)5CO-, and can be derived from a divalent alcohol and ε-caprolactone, etc. Furthermore, there are no particular limitations, and for example, ε-caprolactone, etc. can be obtained by ring-opening polymerization using a divalent alcohol as an initiator in the presence of a catalyst.

[0168] The polyester polyol having an average number of functional groups of 2 can be obtained by subjecting a single dibasic acid or a mixture of two or more dibasic acids to a condensation reaction with a single polyol or a mixture of two or more polyols.

[0169] Examples of the dibasic acid 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, suberic acid, azelaic acid, sebacic acid, decanedioic acid, itaconic acid, itaconic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, tetrahydrophthalic acid, and carboxylic acids such as tetrahydrophthalic acid. Among these, adipic acid and sebacic acid are preferably used.

[0170] Examples of the polyol 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, glycerol, pentaerythritol, 2-hydroxymethylpropanediol, ethoxylated trimethylolpropane, 1,3-propanediol, pentane-1,5-diol, heptane-1,7-diol, octane-1,8-diol, nonane-1,9-diol, decane-1,10-diol, and dodecane- 1,12-diol, cyclohexane-1,4-dimethanol, 4,4'-(1-methylethylene)bicyclohexanol, 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, 2-methyl-1,3-propanediol, etc. Among them, diethylene glycol, 1,3-butanediol, 1,4-butanediol, and 3-methyl-1,5-pentanediol are preferred.

[0171] The polyester polyol having an average functional group number of 2 is preferably a polycaprolactone polyol having an average functional group number of 2, a polyester polyol which is a condensate of a dibasic acid having an average functional group number of 2 and a polyol, or a mixture thereof.

[0172] When a polyisocyanate composition using a polyester polyol having an average functional group number of 2 is used as a curing agent and an aspartic acid ester compound is used as a main agent, the compatibility between the main agent and the curing agent becomes high. Therefore, the polyisocyanate composition of the present embodiment can be suitably used as a curing agent for a polyaspartic acid coating composition using an aspartic acid ester compound as a main agent.

[0173] Furthermore, when a polyester polyol having an average number of functional groups of 2 is used, high flexibility is exhibited by physical crosslinking, and a coating film having high elongation, particularly high elongation at low temperatures, can be produced.

[0174] The number average molecular weight of the polyester polyol having an average number of functional groups of 2 is preferably 250 to 4000, more preferably 250 to 1500, further preferably 250 to 1000, further preferably 300 to 800, and particularly preferably 400 to 800.

[0175] When the number average molecular weight of the polyester polyol having an average number of functional groups of 2 is equal to or greater than the above lower limit, a coating film having high elongation can be produced when used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main component.

[0176] When the number average molecular weight of the polyester polyol having an average number of functional groups of 2 is below the above upper limit, the appearance of the polyisocyanate composition is easily improved. In addition, when used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as the main agent, the coating composition easily maintains a low viscosity. Therefore, the polyisocyanate composition of the present embodiment can be suitably used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as the main agent.

[0177] The number average molecular weight of the polyester polyol having an average number of functional groups of 2 is a number average molecular weight based on polystyrene as measured by GPC, and can be measured by the method described in Examples below.

[0178] In the method for producing polycaprolactone polyol, as an initiator, diols such as ethylene glycol, propylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, pentaerythritol, 2-hydroxymethylpropanediol, 2-ethyl-1,3-hexanediol, 1,3-propanediol, pentane-1,5-diol, heptane-1,7-diol, octane-1,8-diol, nonane-1,6-diol, 1,6-hexane ... 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. Among them, diethylene glycol, 1,3-butanediol, 1,4-butanediol and 3-methyl-1,5-pentanediol are preferred.

[0179] As the catalyst, preferably used are organic titanium 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 the polyester polyol having an average number of functional groups of 2, the catalyst is preferably a tin compound.

[0180] Ring-opening polymerization of ε-caprolactone and the like is preferably carried out under a nitrogen atmosphere. ε-caprolactone and the aforementioned initiator are charged in a molar ratio set to achieve a predetermined molecular weight. Furthermore, a catalyst is added in an amount of 0.1 to 100 ppm by mass relative to the ε-caprolactone. The reaction is then carried out at a temperature of 150°C to 200°C for 4 to 10 hours. However, it is important to control the reaction so that the caprolactone dimer content is 100 to 1000 ppm by mass at the end of the reaction. If necessary, caprolactone dimers can be removed from the resulting polycaprolactone polyol by extraction, distillation, or other methods.

[0181] In addition to ε-caprolactone, a portion of other cyclic lactones such as trimethylcaprolactone and valerolactone may be mixed.

[0182] Polyester polyols can be produced, for example, by subjecting a single dibasic acid or a mixture of dibasic acids to a single polyol or a mixture of polyols through a known condensation reaction. For example, the dibasic acid component and the polyol component can be combined and then heated at about 160 to 220°C.

[0183] The component (A1) in the second embodiment preferably contains, for example, 10 to 90 parts by mass, preferably 20 to 50 parts by mass, of a polyester polyol having an average number of functional groups of 2, per 100 parts by mass of at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates.

[0184] (A2) ingredient

[0185] In the second embodiment of the present embodiment, the 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 functional group number of 2, and a polyoxyalkylene polyol having an average functional group number of 2 to 4.

[0186] Diisocyanate

[0187] The diisocyanate in the component (A2) of the second embodiment can be the same monomer as the diisocyanate in the component (A1), but HDI is preferably used.

[0188] Polyester polyols with an average functional group number of 2

[0189] As the polyester polyol having an average number of functional groups of 2 in the component (A2) of the second embodiment, the same polymer as the polyester polyol having an average number of functional groups of 2 in the component (A1) can be used.

[0190] Polyoxyalkylene polyols

[0191] Polyoxyalkylene polyols are polyols containing -O(CH2) m A polyol having a valence of 2 or more and 4 or less, and having a repeating unit represented by - (wherein m is an integer of 2 or more, preferably an integer of 3 to 5, and more preferably 3 or 4) can be derived from a valence of 2 or more and 4 or less alcohol and ethylene oxide, propylene oxide, tetrahydrofuran, or the like. Furthermore, there are no particular limitations, and for example, ethylene oxide, propylene oxide, tetrahydrofuran, or the like can be obtained by cationic polymerization using a valence of 2 or more and 4 or less alcohol as an initiator in the presence of a catalyst.

[0192] The number average molecular weight of the polyoxyalkylene polyol is preferably 100 or more and 2000 or less, and more preferably 200 or more and 1000 or less.

[0193] When the number average molecular weight of the polyoxyalkylene polyol is at least the above lower limit, when the polyoxyalkylene polyol is used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main component, a coating film having high elongation can be produced.

[0194] When the number average molecular weight of the polyoxyalkylene polyol is below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main agent, the coating composition tends to maintain a low viscosity. Therefore, the polyisocyanate composition of the present embodiment can be suitably used as a curing agent for a polyaspartic acid coating composition containing an aspartic acid ester compound as a main agent.

[0195] The number average molecular weight of the polyoxyalkylene polyol is a number average molecular weight based on polystyrene standards measured by GPC, and can be measured by the method described in Examples below.

[0196] As the initiator, diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, and neopentyl glycol, triols such as trimethylene glycol and glycerol, and tetraols such as pentaerythritol can be used. From the viewpoint of obtaining a low-viscosity polyisocyanate component, branched polyols are preferred.

[0197] As the catalyst, a strong basic catalyst such as a hydroxide of lithium, sodium, potassium, or the like, an alkoxide, or an alkylamine can be used.

[0198] Cationic polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc. is preferably carried out under a nitrogen atmosphere by charging ethylene oxide, propylene oxide, tetrahydrofuran, etc. and the above-mentioned initiator at a molar ratio set to a ratio to achieve a predetermined molecular weight, further adding a catalyst in an amount of 0.1 mass ppm to 100 mass ppm relative to the ethylene oxide, propylene oxide, tetrahydrofuran, etc., and reacting at a temperature of 150° C. to 200° C. for 4 hours to 10 hours.

[0199] In the component (A2) in the second embodiment, for example, 10 to 50 parts by mass, preferably 10 to 30 parts by mass, of a polyester polyol having an average number of functional groups of 2 and 10 to 50 parts by mass, preferably 10 to 30 parts by mass, of a polyoxyalkylene polyol having an average number of functional groups of 2 to 4 are preferably added, relative to 100 parts by mass of at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates.

[0200] Optional ingredients of component (A)

[0201] Furthermore, the component (A) may contain a monohydric alcohol, a dihydric alcohol, or a trihydric alcohol having a branched chain having 2 to 20 carbon atoms as an optional component.

[0202] The monohydric alcohol may contain one or more selected from the group consisting of an ether group, an ester group, a carbonyl group, and a phenyl group in the molecule. For example, it may be benzyl alcohol. Preferably, it is a monohydric alcohol composed solely of saturated hydrocarbon groups. More preferably, it is a branched monohydric alcohol. Examples of such monohydric alcohols 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.

[0203] Examples of the diol include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 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, polypropylene glycol, and polytetramethylene glycol. Straight-chain aliphatic diols such as butylene glycol; branched-chain 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 alone or in combination of two or more. Among these, branched-chain aliphatic diols are preferred because they can further suppress crystallization.

[0204] Examples of the triol include glycerin and trimethylolpropane.

[0205] Among them, component (A) preferably contains as an optional component a diol having a branched chain with a carbon number of 3 to 20, and more preferably contains as an optional component a diol having a branched chain with a carbon number of 3 to 10. By using a diol having a branched chain with a carbon number of 3 to 20, crystallization of the coating composition can be further suppressed.

[0206] The isocyanate content of the (A) component in the second embodiment (hereinafter also referred to as "NCO content") is preferably 5% by mass or more and 30% by mass or less relative to the total amount (100% by mass) of the (A) component. The NCO content is more preferably 6% by mass or more, further 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, further preferably 20% by mass or less. When the NCO content is above the above lower limit, it is easier to maintain the drying and curing properties of the coating film. When the NCO content is below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition, it is easy to improve the scratch resistance of the resulting coating film. The NCO content of the (A) component can be measured by the method described in the examples described later.

[0207] The viscosity of the component (A) in the second embodiment at 25°C is preferably 500 mPa.s or more and 10,000 mPa.s or less. The viscosity is more preferably 600 mPa.s or more, further preferably 700 mPa.s or more, and particularly preferably 1,000 mPa.s or more. The viscosity is more preferably 10,000 mPa.s or less, further preferably 5,000 mPa.s or less, further preferably 2,500 mPa.s or less, and particularly preferably 2,000 mPa.s or less. If the viscosity is above the lower limit, it is easy to improve the scratch resistance of the obtained coating film when used as a curing agent for a polyaspartic acid coating composition. When the viscosity is below the upper limit, it is easier to maintain dryness. The viscosity of the component (A) can be measured at 25°C using an E-type viscometer and measured by the method described in the examples described later.

[0208] The number average molecular weight of the (A) component in the second embodiment is preferably 250 or more and 4000 or less. The number average molecular weight is more preferably 300 or more, particularly preferably 400 or more. The number average molecular weight is more preferably 4000 or less, further preferably 3000 or less, particularly preferably 2000 or less. By making the number average molecular weight more than the above lower limit, when used as a curing agent for a polyaspartic acid coating composition, it is easy to improve the scratch resistance of the obtained coating film. By making the number average molecular weight less than the above upper limit, it is easier to maintain dryness. The number average molecular weight of the (A) component is a number average molecular weight based on a polystyrene benchmark measured by GPC, and can be measured by the method described in the examples described later.

[0209] The average number of isocyanate groups of the component (A) in the second embodiment is preferably 2.0 or more and 10.0 or less. The average number of isocyanate groups is more preferably 2.2 or more, further preferably 2.4 or more, and particularly preferably 2.6 or more. The average number of isocyanate groups is more preferably 9.0 or less, further preferably 8.0 or less, further preferably 7.0 or less, and particularly preferably 3.0 or less. By making the average number of isocyanate groups above the above lower limit, it is easier to maintain dryness. By making the average number of isocyanate groups below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition, it is easy to improve the scratch resistance and weather resistance of the obtained coating film. The average number of isocyanate groups of the component (A) can be measured by the method described in the examples described later.

[0210] The diisocyanate monomer mass concentration of the component (A) in the second embodiment is preferably 1.0 mass % or less, more preferably 0.5 mass % or less, and even more preferably 0.3 mass % or less, relative to the total amount (100 mass %) of the component (A).

[0211] When the diisocyanate monomer mass concentration is below the above upper limit, the drying property can be maintained more easily. The diisocyanate monomer mass concentration of the component (A) can be measured by the method described in the Examples below.

[0212] <<Method for producing component (A)>>

[0213] The component (A) in the second embodiment can be produced by the same method as that of the component (A) in the first embodiment.

[0214] The component (A1) in the second embodiment can be obtained, for example, as follows: relative to 100 parts by mass of at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates, 10 parts by mass to 90 parts by mass, preferably 20 parts by mass to 50 parts by mass of a polyester polyol having an average functional group number of 2 is added, a urethanization reaction is carried out, and then the unreacted diisocyanate monomer is removed to obtain it.

[0215] The component (A2) in the second embodiment can be obtained, for example, as follows: 100 parts by mass of at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates are added with 10 to 50 parts by mass, preferably 10 to 30 parts by mass, of a polyester polyol having an average number of functional groups of 2 and 10 to 50 parts by mass, preferably 10 to 30 parts by mass, of a polyoxyalkylene polyol having an average number of functional groups of 2 to 4, followed by a urethanization reaction, and then removing the unreacted diisocyanate monomer to obtain the component (A2).

[0216] Component (B)

[0217] The component (B) in the second embodiment is a polyisocyanate component obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and a monohydric alcohol having 1 to 20 carbon atoms, wherein the molar ratio of allophanate groups to isocyanurate groups (alophanate groups / isocyanurate groups) is 100 / 0 to 70 / 30.

[0218] Diisocyanate

[0219] Aliphatic diisocyanates are compounds having only aliphatic groups in their molecules, while alicyclic diisocyanates are compounds having cyclic aliphatic groups in their molecules.

[0220] When an aliphatic diisocyanate is used, the resulting polyisocyanate compound has a low viscosity and is therefore more preferred. Examples of the aliphatic diisocyanate include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (hereinafter referred to as HDI), trimethylhexamethylene diisocyanate, and lysine diisocyanate.

[0221] Examples of the alicyclic diisocyanate include isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and 1,4-diisocyanate cyclohexane.

[0222] Among them, HDI, isophorone diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate are preferred because they are easily available industrially. Among them, HDI is most preferred because it is very excellent in weather resistance and coating film flexibility.

[0223] Monohydric alcohol

[0224] As the monohydric alcohol having 1 to 20 carbon atoms in the component (B) of the second embodiment, the same monohydric alcohol as that used in the component (B) of the first embodiment can be used.

[0225] The molar ratio of the allophanate group / isocyanurate group in the component (B) of the second embodiment is as described as the molar ratio of the allophanate group / isocyanurate group in the component (B) of the first embodiment.

[0226] The contents of the uretdione form, urethane form, biuret form, and other diisocyanate polymers in the component (B) of the second embodiment are the same as those described as the contents of the component (B) of the first embodiment.

[0227] <<Method for producing component (B)>>

[0228] The component (B) of the second embodiment can be produced by the same method as that of the component (B) of the first embodiment.

[0229] The NCO content, viscosity, and average number of isocyanate groups of the component (B) of the second embodiment are the same as those described as the NCO content, viscosity, and average number of isocyanate groups of the component (B) of the first embodiment.

[0230] 《Compounding ratio of component (A) and component (B)》

[0231] In the second embodiment, the ratio of the component (A) to the total amount of the component (A) and the component (B) is 60% by mass or more.

[0232] In the second embodiment, the ratio of component (A) to the total amount of components (A) and (B) is preferably 99% by mass or less, more preferably 95% by mass or less, further preferably 90% by mass or less, and particularly preferably 80% by mass or less.

[0233] 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, further 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.

[0234] When the content ratio of component (A) is within the above range, it can be used as a curing agent suitable for polyaspartic acid coating compositions, and a polyisocyanate composition that can impart excellent elongation to the resulting coating film can be obtained. In addition, weather resistance can also be maintained. Polyaspartic acid coating compositions containing component (A) within the above range can suppress crystallization, thereby providing a highly transparent curing agent.

[0235] A polyester polyol having an average functional group number of 2 in component (A) readily crystallizes. Crystallization can easily lead to uneven composition of the components forming the resulting coating film. When components (A) and (B) are included, and the proportion of component (A) within the above range is sufficient, component (A) is less likely to crystallize, and a highly uniform coating film can be readily obtained.

[0236] 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 the (A) component and (B). The NCO content is more preferably 6% by mass or more, and further preferably 7% by mass or more. The NCO content is more preferably 30% by mass or less, further preferably 25% by mass or less, and particularly preferably 14% or less. When the NCO content is above the above lower limit, when used as a curing agent for a polyaspartic acid coating composition, it is easier to maintain the drying and curing properties of the obtained coating film. When the NCO content is below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition, a coating film with high elongation can be manufactured. The NCO content can be measured by the method described in the embodiments described later.

[0237] The viscosity of the polyisocyanate composition of the second embodiment at 25°C is preferably 500 mPa.s or more and 2000 mPa.s or less. The viscosity is more preferably 1700 mPa.s or less, further preferably 1500 mPa.s or less, and particularly preferably 1250 mPa.s or less. If the viscosity is above the above lower limit, when used as a curing agent for a polyaspartic acid coating composition, a coating film with high elongation can be produced. If the viscosity is below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition, it is easy to improve the handleability of the obtained coating composition. The viscosity of the polyisocyanate composition can be measured at 25°C using an E-type viscometer and measured by the method described in the examples described later.

[0238] The average number of isocyanate groups of 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, further preferably 5.0 or less, and particularly preferably 3.0 or less. By making the average number of isocyanate groups above the above lower limit, when used as a curing agent for a polyaspartic acid coating composition, it is easy to maintain the weather resistance of the obtained coating film. By making the average number of isocyanate groups below the above upper limit, when used as a curing agent for a polyaspartic acid coating composition, a coating film with high elongation can be manufactured. The average number of isocyanate groups of the polyisocyanate composition can be measured by the method described in the examples described later.

[0239] Any Ingredient

[0240] In the second embodiment, similarly to the first embodiment, the optional components described in the first embodiment may be contained.

[0241] 《Method for producing polyisocyanate composition》

[0242] The polyisocyanate composition of the present embodiment (first embodiment or second embodiment) can be produced by mixing the above-mentioned component (A) and the above-mentioned component (B) and, if necessary, any optional components.

[0243] For example, the mixing method is not particularly limited, and manual stirring may be performed or a stirring device such as Mazela may be used. If necessary, a solvent may be added to adjust the viscosity.

[0244] <Coating Composition>

[0245] This embodiment is a coating composition comprising a main agent and a curing agent.

[0246] The main agent is an aspartic acid ester compound represented by the following formula (I), and the curing agent is the polyisocyanate composition of the present embodiment (the first embodiment or the second embodiment) described above.

[0247]

[0248] [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 inactive towards isocyanate groups under the reaction conditions, and n is an integer greater than 2.]

[0249] (X)

[0250] In the general formula (I), X is an n-valent organic group.

[0251] As the n-valent organic group, it can be an aliphatic group or an aromatic group. The aliphatic group can be any of linear, branched or cyclic. In addition, n is an integer greater than 2 as described later.

[0252] Examples of the linear or branched aliphatic group include an alkanediyl group (alkylene group), an alkylidene group, and an alkylidyne group.

[0253] Examples of the cyclic aliphatic group include cycloalkylene groups.

[0254] Examples of the aromatic group include arylene groups such as phenylene group.

[0255] More specifically, from the viewpoint of yellowing resistance of the polyaspartic acid coating composition of the present embodiment, X is preferably a linear, branched, or cyclic divalent aliphatic group having 2 to 20 carbon atoms. Examples of the linear, branched, or cyclic divalent aliphatic group having 2 to 20 carbon atoms include n-butylene, n-pentylene, n-hexylene, 2,2,4-trimethylhexamethylene, 2,4,4-trimethylhexamethylene, 3,3,5-trimethyl-5-methylcyclohexylene, dicyclohexylmethylene, and 3,3'-dimethyldicyclohexylmethylene.

[0256] (R 1 and R 2 )

[0257] In the general formula (I), R 1 and R 2 Each is independently an organic group that is inactive toward isocyanate groups under the reaction conditions.

[0258] It should be noted that, in this specification, “inactive to isocyanate groups under the reaction conditions” means that R 1 and R 2 It does not have a group containing Zerewitinoff active hydrogen (CH acidic compound) such as a hydroxyl group, an amino group, or a thiol group.

[0259] R 1 and R 2 Each independently 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.

[0260] R 1 and R 2 Can be the same or different.

[0261] (n)

[0262] In the general formula (I), n is an integer of 2 or greater.

[0263] Among them, n is preferably an integer of 2 to 6, more preferably an integer of 2 to 4, further preferably 2 or 3, and particularly preferably 2.

[0264] 《Method for producing an aspartic acid ester compound represented by formula (I)》

[0265] The aspartic acid ester compound represented by formula (I) can be produced by the method described in International Publication No. 2018 / 163959.

[0266] In the coating composition of this embodiment, the molar ratio NCO / NH is preferably 1.0 to 2.0, more preferably 1.1 to 1.5. The molar ratio NCO / NH can be determined from the NCO content (%) of the polyisocyanate composition and the amine value of the aspartic acid ester compound.

[0267] Additive ingredients

[0268] In this embodiment, the coating composition may include an adsorbent as an additive component. As the adsorbent, a molecular sieve can be preferably used. Molecular sieve is the name of a natural or synthetic zeolite having a high internal surface area and a uniform pore size. Molecular sieves exert a high adsorption capacity and are used as adsorbents and water absorbents. The pore size of the surface of the molecular sieve suitable for use in this embodiment is preferably 2 to 10 angstroms, more preferably 2.5 to 4 angstroms, and further preferably has a pore size of about 3 angstroms.

[0269] The content of the adsorbent is preferably 0.1 to 15 wt %, more preferably 0.5 to 8 wt %, and even more preferably 0.5 to 1.0 wt %, based on the total weight of the coating composition of this embodiment.

[0270] In this embodiment, the coating composition may contain a matting agent as an additive component. The matting agent is not particularly limited, and examples thereof include dry silica, precipitated silica, and the like.

[0271] There are no particular limitations on dry silica, and examples thereof include ACEMATT 3400, ACEMATT 3300, and ACEMATT TS100 (each a trade name) (manufactured by Evonik Japan Co., Ltd.). There are no particular limitations on precipitated silica, and examples thereof 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 alone or in combination of two or more. The matting agent is not particularly limited, but among the above-mentioned ones, dry silica is particularly preferably used.

[0272] The content of the matting agent is preferably 3 to 20% by weight based on the total weight of the solid content of the coating composition of the present embodiment.

[0273] The coating composition of the present embodiment may further contain a polyvalent active hydrogen compound containing a polyol, a melamine resin, an epoxy resin, a polyurethane resin, and the like as additive components, as necessary.

[0274] When the polyol has a carboxyl group, the coating composition of the present embodiment may contain an oxazoline group-containing compound and a carbodiimide group-containing compound.

[0275] When the polyol has a carbonyl group, the coating composition of this embodiment may be blended with a hydrazide group-containing compound or a semicarbazide group-containing compound. These compounds may be blended alone or in combination of two or more.

[0276] From the viewpoint of obtaining a coating film with excellent appearance, the coating composition of this embodiment preferably further contains a surface conditioner as an additive component. The type of surface conditioner is not particularly limited, and examples thereof include silicone-based and acrylic-based agents.

[0277] The content of the surface conditioner is preferably 0.05% by mass or more and 5% by mass or less relative to the resin component of the coating composition. By setting the content of the surface conditioner to be equal to or greater than the above lower limit, a coating film having excellent appearance can be produced.

[0278] Furthermore, by making the content of the surface conditioner equal to or less than the above upper limit, the crater resistance, recoatability, and stain resistance of the coating film are further improved.

[0279] As the silicone surface conditioner, commercially available products can be used, for example, 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); DISPARLON 1711EF, DISPARLON 1761, DISPARLON LS-001, DISPARLON LS-050, DISPARLON LS-280, DISPARLON LS-460, DISPARLON LS-480 (manufactured by Kusumoto Chemicals Co., Ltd.); TegoFlow 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, Tegowet 260, Tego wet 265, Tego wet 270, Tego wet 280 (manufactured by Evonik Tego Chemie), etc. These may be used alone or in combination of two or more.

[0280] As acrylic surface conditioners, commercially available products can be used, for example, BYK-350, BYK-354, BYK-355, BYK-356, BYK-358N, BYK-361N, BYK-392, BYK-394, BYK-3441 (manufactured by BYK); DISPARLON LF-1983, DISPARLON LF-1984, LF-1985, DISPARLON UVX-35, DISPARLON UVX-36 (manufactured by Kusumoto Chemicals Co., Ltd.); Tego Flow 300, Tego Flow 370, Tego Flow ATF2, Tego Flow ZFS460 (manufactured by Evonik Tego Chemie), etc. These may be used alone or in combination of two or more.

[0281] As other types of surface conditioners other than those mentioned above, commercially available products can be used, for example, BYK-399, BYK-3440, BYK-3550, BYK-3560, BYK-3565, BYK-SILCLEAN 3700, BYK-SILCLEAN 3701, BYKETOL-OK (manufactured by BYK); DISPARLON UVX-272, DISPARLON UVX-2285, DISPARLON LHP-810, DISPARLON NSH-8430HF, DISPARLON LHP-90, DISPARLON LHP-91, DISPARLON LHP-95, DISPARLON LHP-96 (manufactured by Kusumoto Chemicals Co., Ltd.), etc. These may be used alone or in combination of two or more.

[0282] From the perspective of obtaining a coating film with excellent appearance, the coating composition of this embodiment may further contain a defoamer, an inhibitor, or a degassing agent as additive components. The type of the defoamer, inhibitor, or degassing agent is not particularly limited, and examples thereof include silicone-based and polymer-based agents.

[0283] The content of defoamer, foam suppressant, and air release agent is preferably 0.05% by mass or more and 5% by mass or less relative to the resin component of the coating composition. By making the content of defoamer, foam suppressant, and air release agent above the above lower limit, the workability during coordination and stirring can be improved, and a coating film with excellent appearance can be produced. On the other hand, by making the content of defoamer, foam suppressant, and air release agent below the above upper limit, the shrinkage cavity resistance, recoatability, and pollution resistance when producing the coating film become better.

[0284] As the silicone defoaming agent, foam suppressant, and air release agent, commercially available products can be used, for example, BYK-063, BYK-065, BYK-066N, BYK-067A, BYK-077, BYK-081, BYK-1799 (manufactured by BYK); DISPARLON 1930N, DISPARLON 1934, DISPARLON SPX-44 (manufactured by Kusumoto Chemicals 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), etc. These may be used alone or in combination of two or more.

[0285] As the polymer defoaming agent, foam suppressant, and air release agent, 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); DISPARLON OX-60, DISPARLON OX-6140, DISPARLON OX-70, DISPARLON OX-710, DISPARLON OX-750HF, DISPARLON OX-77EF, DISPARLON OX-880EF, DISPARLON OX-881, DISPARLON OX-883HF, DISPARLON LAP-10, DISPARLON LAP-20, DISPARLON LAP-30, DISPARLON 1952, DISPARLON 1958, DISPARLON 1960, DISPARLON P-410EF, DISPARLON PD-7, DISPARLON P-420, DISPARLON P-450, DISPARLON OX-881, DISPARLON OX-883HF, DISPARLON LAP-10, DISPARLON P-425, DISPARLON UVX-188, DISPARLON UVX-189, DISPARLON UVX-190 (manufactured by Kusumoto Chemical Co., Ltd.); Tego Airex 910, TegoAirex920, Tego Airex 936, Tego Airex 944, Tego Airex 955 (manufactured by Evonik Tego Chemie Co., Ltd.), etc. These may be used alone or in combination of two or more.

[0286] As other types of defoamers, foam suppressants, and air release agents other than those mentioned above, commercially available products can be used, for example, BYK-088, BYK-141 (manufactured by BYK Corporation); DISPARLON OX-66EF, DISPARLON OX-715 (manufactured by Kusumoto Chemicals Co., Ltd.); Tego Airex 940, Tego Airex 945, Tego Airex 950, Tego Airex 986 (manufactured by Evonik Tego Chemie Co., Ltd.), etc. These may be used alone or in combination of two or more.

[0287] The coating composition of the present embodiment may further contain a dispersant as an additive component as necessary.

[0288] As the dispersant, a commercially available product can be used, and examples thereof include DESPERBYK-103, DESPERBYK-145, DESPERBYK-2155, and DESPERBYK-2159 (manufactured by BYK).

[0289] These may be used alone or in combination of two or more.

[0290] In addition, as additive components, it may further include: pigments such as titanium oxide, carbon black, indigo, quinacridone, pearl mica; metal powder pigments such as aluminum; rheology control agents such as hydroxyethyl cellulose, urea compounds, microgels; curing accelerators such as tin compounds, zinc compounds, amine compounds; ultraviolet absorbers, light stabilizers, antioxidants, etc. recorded as any of the aforementioned components.

[0291] The coating composition of this embodiment is preferably a coating for building structures.

[0292] Examples of the paint for building structures include paint for building floors, building walls, building roofs, and building parts, such as paint for wind turbines or helicopter rotor blades, aircraft wings, and ship propellers.

[0293] The coating composition of the present invention can produce a flexible coating film with an increased crosslinking density. Such a coating film exhibits exceptional weather resistance, making it suitable for heavy-duty corrosion protection coatings on structures exposed to harsh environments such as wind, rain, snow, and temperature fluctuations, such as bridges, highways, transmission towers, and wind turbine power generation equipment (towers, blades, etc.), which require long-term weather resistance.

[0294] Furthermore, the coating composition of the present invention is suitable for imparting aesthetic properties, weather resistance, acid resistance, rust resistance, chipping resistance, adhesion, and the like.

[0295] Furthermore, the coating composition of the present invention is also useful as an adhesive, a pressure-sensitive adhesive, an elastomer, a foam, a surface treatment agent, and the like.

[0296] <Coating>

[0297] The present embodiment is a coating film formed by curing the coating composition of the present embodiment described above.

[0298] The coating film of the present embodiment is obtained by applying the coating composition using a known method such as roller coating, curtain coating, spray coating, bell coating, or electrostatic coating, and curing the coating composition through a room temperature drying or baking step.

[0299] The coating film of this embodiment has excellent elongation.

[0300] Example

[0301] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following Examples unless it exceeds the gist of the present invention.

[0302] The physical properties of the polyisocyanate compositions in Examples and Comparative Examples were measured and evaluated as follows: Unless otherwise specified, "parts" and "%" refer to "parts by mass" and "% by mass."

[0303] <Synthesis example 1-1>

[0304] (A1)1-1 as the component (A) was synthesized by the following method.

[0305] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel was placed under a nitrogen atmosphere. 100 parts of HDI and 33.7 parts of polycaprolactone triol with a number average molecular weight of 850 and a hydroxyl value of 198 were added. The urethanization reaction was carried out while the reactor temperature was maintained at 95°C for 90 minutes under stirring. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. This yielded polyisocyanate (A1) 1-1 having 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 concentration of 0.2% by mass.

[0306] <Synthesis example 1-2>

[0307] (A2)1-1 as the component (A) was synthesized by the following method.

[0308] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel was placed under a nitrogen atmosphere. 100 parts of HDI, 6.9 parts of polycaprolactone triol with a number average molecular weight of 550 and a hydroxyl value of 305, and 12.8 parts of polytetramethylene glycol with a number average molecular weight of 1000 and a hydroxyl value of 112 were added. The urethanization reaction was carried out while stirring while maintaining the temperature in the reactor at 90°C for 1 hour. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. This yielded polyisocyanate (A2) 1-1 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 concentration of 0.2% by mass.

[0309] <Synthesis Example 1-3>

[0310] (B)1-1 as the component (B) was synthesized by the following method.

[0311] The atmosphere in 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 added. The urethanization reaction was carried out at 130°C for 1 hour with stirring. 0.54 g of a 20% solids solution of zirconyl 2-ethylhexanoate in mineral spirits was added as an allophanation catalyst. When the refractive index of the reaction solution rose to 0.0055, 0.81 g of a 50% isobutyl alcohol solution of lauryl phosphate (a solution prepared by diluting "JP-512" manufactured by Johoku Chemical Industry Co., Ltd. with isobutyl alcohol) (4.0 times the molar amount relative to the catalyst) was added to terminate the reaction. The reaction solution was filtered, and unreacted HDI was removed using a downflow thin-film distillation apparatus at a first distillation step of 160°C (27 Pa) and a second distillation step of 150°C (13 Pa). The obtained polyisocyanate was a transparent liquid with a yield of 770 g, a viscosity of 110 mPa·s, and an NCO content of 17.2%. NMR analysis revealed an allophanate group / isocyanurate group molar ratio of 97 / 3. The obtained polyisocyanate was designated as (B)1-1.

[0312] <Examples 1-1 to 1-9, Comparative Examples 1-1 to 1-4>

[0313] Using (A1) 1-1, (A2) 1-1, (B) 1-1, and optional components, the polyisocyanate compositions of Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-4 were obtained.

[0314] As an optional component, a hindered amine compound, Tinuvin 765 (manufactured by BASF Japan Co., Ltd.) was used.

[0315] The mixing ratio of each component, the physical properties of the component (A), and the physical properties of the polyisocyanate composition are shown in the following Tables 1-1 and 1-2.

[0316] [Table 1-1]

[0317]

[0318] [Table 1-2]

[0319]

[0320] In Table 1-1 and Table 1-2, physical properties 1-1 to 1-5 respectively show the following physical properties.

[0321] (Physical Properties 1-1) NCO Content (Mass %)

[0322] The NCO content (isocyanate content, mass %) of the polyisocyanate is measured as follows. 1 to 3 g of the polyisocyanate manufactured in the manufacturing example is accurately weighed (W g) in a conical flask, 20 mL of toluene is added, and the polyisocyanate is completely dissolved. Then, 10 mL of a toluene solution of 2 equivalents of di-n-butylamine is added, and after complete mixing, it is left at room temperature for 15 minutes. Furthermore, 70 mL of isopropanol is added to the solution and completely mixed. The solution is titrated with an indicator using 1 equivalent hydrochloric acid solution (factor F) to obtain a titration value V2 mL. For the same titration operation, the titration value V1 mL is obtained without using polyisocyanates. According to the obtained titration value V2 mL and titration value V1 mL, the NCO content of the polyisocyanate is calculated based on the following formula.

[0323] NCO content = (V1-V2)×F×42 / (W×1000)×100

[0324] (Physical Properties 1-2) Viscosity (mPa.s)

[0325] The viscosity of the polyisocyanate was measured at 25° C. using an E-type viscometer (trade name: RE-85R, manufactured by Toki Sangyo Co., Ltd.) A standard rotor (1°34′×R24) was used for the measurement, and the rotation speed was set as follows.

[0326] 100r.pm (less than 128mPa.s)

[0327] 50 rpm (128 mPa.s or higher and less than 256 mPa.s)

[0328] 20 rpm (256 mPa.s or higher and less than 640 mPa.s)

[0329] 10 rpm (640 mPa.s or higher and less than 1280 mPa.s)

[0330] 5r.pm (1280mPa.s or more and less than 2560mPa.s)

[0331] 2.5rpm (2560mPa.s or more and less than 5184mPa.s)

[0332] 1.0 rpm (5184 mPa.s or more and less than 12960 mPa.s)

[0333] 0.5 rpm (12960 mPa.s or more and less than 25920 mPa.s)

[0334] (Physical Properties 1-3) Number Average Molecular Weight

[0335] The number average molecular weight of the polyisocyanate, polyester polyol, and polyoxyalkylene polyol was determined from the number average molecular weight based on polystyrene measured by gel permeation chromatography (hereinafter abbreviated as "GPC") using the following apparatus.

[0336] Device: "HLC-8120GPC" (trade name) manufactured by Tosoh Corporation

[0337] Column: "TSKgel SuperH1000" (trade name) manufactured by Tosoh Corporation × 1

[0338] "TSKgel SuperH2000" (brand name) × 1

[0339] "TSKgel SuperH3000" (brand name) × 1

[0340] Carrier: Tetrahydrofuran

[0341] Detection method: Differential refractometer

[0342] (Physical Properties 1-4) Average Number of Isocyanate Groups

[0343] The average number of isocyanate groups in the polyisocyanate was calculated from (physical property 1-1) NCO content and (physical property 1-3) number average molecular weight based on the following formula.

[0344] Average number of isocyanate groups = [number average molecular weight × NCO content (%)] / 4200

[0345] (Physical Property 1-5) Diisocyanate Monomer Mass Concentration (Mass %)

[0346] The diisocyanate mass concentration of a polyisocyanate is determined as follows. First, place a 20 mL sample bottle on a digital balance and accurately weigh approximately 1 g of the sample. Next, add 0.03-0.04 g of nitrobenzene (internal standard solution) and accurately weigh it. Finally, add approximately 9 mL of ethyl acetate, securely cap, and mix thoroughly to prepare the sample. The prepared sample is analyzed and quantified by gas chromatography under the following conditions.

[0347] Device: GC-8A manufactured by Shimadzu Corporation

[0348] Column: "Silicone OV-17" manufactured by Shinwa Chemical Co., Ltd.

[0349] Column oven temperature: 120°C

[0350] Injection / detector temperature: 160°C

[0351] <Manufacturing of Coating Composition>

[0352] As the main agent, "FEISARATIC F420" (aspartic acid ester compound, trade name of Zhuhai Feiyang Protech Co., Ltd., amine value 201 mgKOH / resin g: In formula (I), X is dicyclohexylmethylene, R 1 is ethyl, R 2 In Tables 1-3 and 1-4, aspartic acid ester compounds are described as "PAE".

[0353] As a curing agent, the component (A) or the polyisocyanate composition obtained above was used. Specific materials are shown in Tables 1-3 and 1-4.

[0354] The base agent and curing agent were blended at an NCO / NH ratio of 1.1, and the mixture was adjusted with n-butyl acetate to a coating solid content of 90% by mass, to obtain coating compositions P1-1 to P1-6, P1-8, P1-9, P1-11 to P1-14, and coating compositions 1-1 to 1-6, 1-8, 1-9, and 1-11 to 1-14, respectively. The base agent and curing agent were blended at an NCO / NH ratio of 1.1, and the mixture was adjusted with n-butyl acetate to a coating solid content of 80% by mass, to obtain coating compositions P1-7 and 1-7, respectively.

[0355] In addition, the additive components (adsorbent, matting agent) of the coating compositions described in Tables 1-3 and 1-4 are the following materials.

[0356] Adsorbent: Molecular sieve, 3APowder manufactured by United Showa Corporation (pore size approximately 3 angstroms).

[0357] Matting agent: ACEMATT 3400 manufactured by Evonik Japan.

[0358] In Tables 1-3 and 1-4, the content ratio of the additive components is the ratio relative to the total mass of the solid content of the coating composition.

[0359] [Table 1-3]

[0360]

[0361] [Table 1-4]

[0362]

[0363] Evaluation of coating properties

[0364] (Preparation of whiteboard)

[0365] A whiteboard substrate was prepared by spraying a commercially available solvent-based two-component acrylic urethane white enamel paint onto an aluminum plate and allowing it to solidify. The paint was then baked at 80°C for 2 hours, aged at room temperature for at least 2 weeks, and then polished with #1000 sandpaper until the 60-degree gloss value reached 10% or less.

[0366] [Weather resistance]

[0367] The resulting coating compositions were applied to white panels using an applicator to a dry film thickness of 80 μm to 100 μm, and dried at 23°C for 7 days to obtain cured coating films. The time it took for the gloss retention to reach 80% or less was then evaluated using a dew panel light control weather meter (FDP) manufactured by Suga Test Instruments Co., Ltd. under the conditions of JIS K5600-7-8.

[0368] [Elongation at break]

[0369] The obtained coating compositions were applied using an applicator so that the dry film thickness became 80 μm or more and 100 μm or less, and dried at 23° C. for 7 days to obtain cured thin films.

[0370] The obtained cured film was measured for elongation at break under the following measurement conditions using Tensilon manufactured by Orientec Corporation.

[0371] Measurement conditions

[0372] Chuck distance: 20mm

[0373] Speed: 20mm / min

[0374] Measuring temperature: 23℃, -20℃

[0375] Tables 1-5 and 1-6 show the elongation at break at 23°C and -20°C (unit: %), respectively.

[0376] [Evaluation of elongation]

[0377] The elongation (unit: %) was calculated from the elongation at break of the coating film 1-1 and the elongation at break of the coating film P1-1 according to the following formula.

[0378] (Elongation at break of coating film 1-1 / Elongation at break of coating film P1-1)×100

[0379] The elongation was calculated similarly for each of the 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.

[0380] The calculated elongation was evaluated according to the following criteria.

[0381] ○: Elongation is 110% or more.

[0382] Δ: The elongation is 100% or more and less than 110%.

[0383] ×: Elongation is less than 100%.

[0384] [Glossiness (60°)]

[0385] The obtained coating compositions P1-7 and 1-7 were applied to ABS plates (black Mitsubishi resin 802) using an applicator to a dry film thickness of 80 μm or more and 100 μm or less, and dried at 23°C for 7 days to obtain cured coating films, coating films P1-7, and coating films 1-7. The gloss value at 60° was then evaluated using a gloss meter (Haze-Gloss BYK Gardner).

[0386] [Table 1-5]

[0387]

[0388] [Table 1-6]

[0389]

[0390] As shown in the above results, it was confirmed that, when the polyisocyanate composition of the present embodiment (first embodiment) is used as a curing agent, a coating film having excellent weather resistance and elongation can be obtained.

[0391] <Synthesis example 2-1>

[0392] (A1)2-1 as the component (A) was synthesized by the following method.

[0393] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was placed under a nitrogen atmosphere. 430.0 parts of HDI; 73.9 parts of a polycaprolactone diol with a number average molecular weight of 400 and a hydroxyl value of 283, formed from ε-caprolactone and 1,4-butanediol; and 73.9 parts of a polycaprolactone diol with a number average molecular weight of 830 and a hydroxyl value of 131, formed from ε-caprolactone and diethylene glycol, were added. The urethanization reaction was carried out while stirring, maintaining the reactor temperature at 100°C for 120 minutes. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. The resultant polyisocyanate (A1) 2-1 had 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.

[0394] <Synthesis example 2-2>

[0395] (A1)2-2 as the component (A) was synthesized by the following method.

[0396] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was placed under a nitrogen atmosphere. 450.0 parts of HDI; 66.3 parts of a polycaprolactone diol (number average molecular weight 400, hydroxyl number 283) formed from ε-caprolactone and 1,4-butanediol; and 66.3 parts of a polyester diol (number average molecular weight 500, hydroxyl number 223) formed from adipic acid and 3-methyl-1,5-pentanediol were added. The urethanization reaction was carried out while stirring at 100°C for 120 minutes. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. The resultant polyisocyanate (A1) 2-2 had 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.

[0397] <Synthesis example 2-3>

[0398] (A1)2-3 as the component (A) was synthesized by the following method.

[0399] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel was placed under a nitrogen atmosphere. 420.0 parts of HDI and 170.0 parts of polycaprolactone diol (e-caprolactone and diethylene glycol) with a number-average molecular weight of 830 and a hydroxyl value of 131 were added. The reactor temperature was maintained at 100°C for 120 minutes while stirring to allow a urethanization reaction to proceed. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. This yielded polyisocyanate (A1) 2-3 having 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.

[0400] <Synthesis example 2-4>

[0401] (A2)2-1 as the component (A) was synthesized by the following method.

[0402] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was placed under a nitrogen atmosphere. 440.0 parts of HDI, 74.0 parts of polycaprolactone diol (number average molecular weight 400, hydroxyl number 283) formed from ε-caprolactone and 1,4-butanediol, and 74.0 parts of polypropylene glycol (number average molecular weight 1000, hydroxyl number 111) were added. The urethanization reaction was carried out while stirring at 100°C for 120 minutes. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. The resultant polyisocyanate (A2) 2-1 had 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.

[0403] <Synthesis example 2-5>

[0404] (A2)2-2 as the component (A) was synthesized by the following method.

[0405] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel was placed under a nitrogen atmosphere. 470.0 parts of HDI, 56.9 parts of polycaprolactone diol (number average molecular weight 550, hydroxyl number 208) formed from ε-caprolactone and diethylene glycol, and 56.9 parts of polypropylene glycol (number average molecular weight 227, hydroxyl number 494) were added. A urethanization reaction was carried out while stirring, maintaining the reactor temperature at 100°C for 120 minutes. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. This yielded polyisocyanate (A2) 2-2 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.

[0406] <Synthesis example 2-6>

[0407] (A2)2-3 as the component (A) was synthesized by the following method.

[0408] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was placed under a nitrogen atmosphere. 420.0 parts of HDI, 68.9 parts of polycaprolactone diol (number average molecular weight 400, hydroxyl number 283) formed from ε-caprolactone and 1,4-butanediol, and 68.9 parts of polytetramethylene glycol (number average molecular weight 655, hydroxyl number 172) were added. The urethanization reaction was carried out while stirring at 100°C for 120 minutes. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. The resultant polyisocyanate (A2) 2-3 had 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.

[0409] <Synthesis example 2-7>

[0410] (A1)2-4 as the component (A) was synthesized by the following method.

[0411] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was placed under a nitrogen atmosphere. 430.0 parts of HDI, 64.9 parts of a polycaprolactone diol (number average molecular weight 400, hydroxyl number 283) formed from ε-caprolactone and 1,4-butanediol, and 64.9 parts of a polycaprolactone diol (number average molecular weight 550, hydroxyl number 208) formed from ε-caprolactone and diethylene glycol were added. The urethanization reaction was carried out while stirring at 100°C for 120 minutes. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. This yielded 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.

[0412] <Synthesis example 2-8>

[0413] (A1) 2-5 as the component (A) was synthesized by the following method.

[0414] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was placed under a nitrogen atmosphere. 400 parts of HDI and 125 parts of a polyester diol (sebacic acid and 3-methyl-1,5-pentanediol) with a number-average molecular weight of 490 and a hydroxyl value of 223 were added. The urethanization reaction was carried out while maintaining the reactor temperature at 100°C for 120 minutes. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. This yielded 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.

[0415] <Synthesis example 2-9>

[0416] (A1) 2-6 as the component (A) was synthesized by the following method.

[0417] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was placed under a nitrogen atmosphere. 400 parts of HDI and 127 parts of a polyester diol (number-average molecular weight 504, hydroxyl number 223) formed from adipic acid and 3-methyl-1,5-pentanediol were added. The urethanization reaction was carried out while the reactor temperature was maintained at 100°C for 120 minutes under stirring. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. This yielded 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.

[0418] <Synthesis example 2-10>

[0419] (A1)2-7 as the component (A) was synthesized by the following method.

[0420] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was placed under a nitrogen atmosphere. 400 parts of HDI, 95.1 parts of polycaprolactone diol (number-average molecular weight 550, hydroxyl value 208) formed from ε-caprolactone and diethylene glycol, and 10.6 parts of 1,3-butanediol were added. The urethanization reaction was carried out while stirring at 100°C for 120 minutes. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. The resultant polyisocyanate (A1) 2-7 had 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.

[0421] <Synthesis example 2-11>

[0422] (A1)2-8 as the component (A) was synthesized by the following method.

[0423] A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and dropping funnel was placed under a nitrogen atmosphere. 400.0 parts of HDI, 130.0 parts of a polycaprolactone diol composed of ε-caprolactone and diethylene glycol (number average molecular weight of 550, hydroxyl value of 208), and a urethanization reaction was carried out while maintaining the temperature in the reactor at 100°C for 120 minutes. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. This yielded polyisocyanate (A1) 2-8 having 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.

[0424] <Synthesis example 2-12>

[0425] (B)2-1 as the component (B) was synthesized by the following method.

[0426] The atmosphere in 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 added. The urethanization reaction was carried out at 130°C for 1 hour with stirring. 0.54 g of a 20% solids solution of zirconyl 2-ethylhexanoate in mineral spirits was added as an allophanation catalyst. When the refractive index of the reaction solution rose to 0.0055, 0.81 g of a 50% isobutyl alcohol solution of lauryl phosphate (a solution prepared by diluting "JP-512" manufactured by Johoku Chemical Industry Co., Ltd. with isobutyl alcohol) (4.0 times the molar amount relative to the catalyst) was added to terminate the reaction. The reaction solution was filtered, and unreacted HDI was removed using a downflow thin-film distillation apparatus at a first distillation step of 160°C (27 Pa) and a second distillation step of 150°C (13 Pa). The obtained polyisocyanate was a transparent liquid with a yield of 770 g, a viscosity of 110 mPa·s, and an NCO content of 17.2%. NMR analysis revealed an allophanate group / isocyanurate group molar ratio of 97 / 3. The obtained polyisocyanate was designated as (B)2-1.

[0427] As a light stabilizer, Tinuvin 765 manufactured by BASF Japan Co., Ltd. was prepared.

[0428] <Examples 2-1 to 2-14, Comparative Examples 2-1 to 2-2>

[0429] The polyisocyanate compositions of Examples 2-1 to 2-14 and Comparative Examples 2-1 to 2-2 were obtained using polyisocyanates (A1) 2-1 to (A1) 2-8, (A2) 2-1 to (A2) 2-3, (B) 2-1, and any light stabilizer.

[0430] The mixing ratio of each component, the physical properties of the component (A) alone, and the physical properties of the polyisocyanate composition are shown in the following Tables 2-1 to 2-3.

[0431] [Table 2-1]

[0432]

[0433] [Table 2-2]

[0434]

[0435] [Table 2-3]

[0436]

[0437] In Tables 2-1 to 2-3, physical properties 2-1 to 2-5 respectively show the following physical properties.

[0438] (Physical Properties 2-1) NCO Content (Mass %)

[0439] Calculate by the same method as in Physical Property 1-1.

[0440] (Physical Properties 2-2) Viscosity (mPa.s)

[0441] The measurement was performed in the same manner as in Physical Property 1-2.

[0442] (Physical Properties 2-3) Number Average Molecular Weight

[0443] The number average molecular weight of the polyisocyanate was determined by the same method as in Physical Property 1-3.

[0444] (Physical Property 2-4) Average Number of Isocyanate Groups

[0445] The average number of isocyanate groups in the polyisocyanate was determined by the same method as in Physical Property 1-4. (Physical Property 2-5) Diisocyanate Monomer Mass Concentration (Mass %)

[0446] The diisocyanate mass concentration of the polyisocyanate was determined by the same method as in Physical Property 1-5.

[0447] (Appearance evaluation)

[0448] The component (A) or the polyisocyanate composition immediately after production was placed at 23° C., and the transmittance was measured and evaluated according to the following criteria. A higher transmittance value indicates higher transparency.

[0449] Equipment: JASCO V-650 UV-visible spectrophotometer manufactured by JASCO Corporation

[0450] Measurement wavelength: 550nm

[0451] Cuvette length: 20mm

[0452] 〇:More than 90%

[0453] △: 60% or more and less than 90%

[0454] ×: less than 60%

[0455] <Manufacturing of Coating Composition>

[0456] As the main agent, "FEISARATIC F420" (aspartic acid ester compound, trade name of Zhuhai Feiyang Protech Co., Ltd., amine value 201 mgKOH / resin g) was used. In Tables 2-4 and 2-5, the aspartic acid ester compound is described as "PAE".

[0457] As a curing agent, the component (A) or the polyisocyanate composition obtained above was used. Specific materials are shown in Tables 2-4 and 2-5.

[0458] The main agent and curing agent were mixed at a ratio of NCO / NH=1.1, and the coating solid content was adjusted with n-butyl acetate to 90% by mass, to obtain coating compositions P2-1 to P2-10, P2-12 to P2-18, and coating compositions 2-1 to 2-10, and 2-12 to 2-18, respectively.

[0459] The main agent and the curing agent were mixed at a ratio of NCO / NH=1.1, and the ratio was adjusted with n-butyl acetate so that the coating solid content was 80% by mass to obtain coating compositions P2-11 and 2-11.

[0460] In addition, the additive components (adsorbent, matting agent) of the coating compositions described in Tables 2-4 and 2-5 are the following materials.

[0461] Adsorbent: Molecular sieve, 3APowder manufactured by United Showa Corporation (pore size approximately 3 angstroms).

[0462] Matting agent: ACEMATT 3400 manufactured by Evonik Japan.

[0463] In Tables 2-4 and 2-5, the content ratio of the additive components is the ratio relative to the total weight of the solid content of the coating composition.

[0464] [Table 2-4]

[0465]

[0466] [Table 2-5]

[0467]

[0468] Evaluation of coating properties

[0469] (Preparation of whiteboard)

[0470] A whiteboard substrate was prepared by spraying a commercially available solvent-based two-component acrylic urethane white enamel paint onto an aluminum plate and allowing it to solidify. The paint was then baked at 80°C for 2 hours, aged at room temperature for at least 2 weeks, and then polished with #1000 sandpaper until the 60° gloss value reached 10% or less.

[0471] [Weather resistance]

[0472] The resulting coating compositions were applied to white panels using an applicator to a dry film thickness of 80 μm to 100 μm, and dried at 23°C for 7 days to form cured coatings. The time it took for the gloss retention to reach 80% or less was then evaluated using a Suga Test Instruments Co., Ltd. exposed panel light control weathering tester (FDP) under the conditions of JIS K5600-7-8.

[0473] [Elongation at break]

[0474] The obtained coating compositions were applied using an applicator so that the dry film thickness became 80 μm or more and 100 μm or less, and dried at 23° C. for 7 days to obtain cured thin films.

[0475] The obtained cured film was measured for elongation at break under the following measurement conditions using Tensilon manufactured by Orientec Corporation.

[0476] Measurement conditions

[0477] Chuck distance: 20mm

[0478] Speed: 20mm / min

[0479] Measuring temperature: 23℃, -20℃

[0480] Tables 2-6 to 2-8 show the elongation at break at 23°C and -20°C (unit: %), respectively.

[0481] [Evaluation of elongation]

[0482] The elongation (unit: %) was calculated from the elongation at break of the coating film 2-1 and the elongation at break of the coating film P2-1 according to the following formula.

[0483] (Elongation at break of coating film 2-1 / Elongation at break of coating film P2-1)×100

[0484] The elongation was calculated similarly for each of the 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.

[0485] The calculated elongation was evaluated according to the following criteria.

[0486] ○: Elongation is 110% or more.

[0487] Δ: The elongation is 100% or more and less than 110%.

[0488] ×: Elongation is less than 100%.

[0489] [Glossiness (60 degree gloss value)]

[0490] The resulting coating compositions P2-11 and 2-11 were each applied to an ABS plate (Mitsubishi Resin 802 Black) using an applicator to a dry film thickness of 80 μm to 100 μm, and dried at 23°C for 7 days to obtain cured coating films, coating films P2-11, and coating films 2-11. The gloss values at 60 degrees were then evaluated using a gloss meter (Haze-Gloss BYK Gardner).

[0491] [Table 2-6]

[0492]

[0493] [Table 2-7]

[0494]

[0495] [Table 2-8]

[0496]

[0497] As shown in the above results, it was confirmed that the polyisocyanate composition of this embodiment (second embodiment) has an excellent transparent appearance, and when the polyaspartic acid coating composition is used as a curing agent, a coating film with excellent elongation and excellent elongation at break at low temperature can be obtained.

[0498] Industrial applicability

[0499] The polyisocyanate composition of the present invention is useful as a curing agent for polyaspartic acid coating compositions.

Claims

1. A polyisocyanate composition comprising component (A) and component (B), The component (A) is the component (A1) or the component (A2), The 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 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 or 3, and a polyoxyalkylene polyol having an average number of functional groups of 2 to 4. The 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 monohydric alcohol having 1 to 20 carbon atoms, wherein the molar ratio of allophanate groups to isocyanurate groups (alophanate groups / isocyanurate groups) is 100 / 0 to 70 / 30. The ratio of the component (A) to the total amount of the component (A) and the component (B) is 60% by mass or more.

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

3. The polyisocyanate composition according to claim 2, wherein The number average molecular weight of the polyester polyol is 250 or more and 4000 or less, The number average molecular weight of the polyoxyalkylene polyol is 200 or more and 1500 or less.

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

5. The polyisocyanate composition according to claim 4, wherein The number average molecular weight of the polyester polyol is 250 or more and 4000 or less, The number average molecular weight of the polyoxyalkylene polyol is 100 or more and 2000 or less. The polyisocyanate composition according to claim 1 , comprising either or both of an ultraviolet absorber and a light stabilizer.

7. A coating composition comprising a main agent and a curing agent, The main agent is an aspartic acid ester compound represented by the following formula (I): The curing agent is the polyisocyanate composition according to claim 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 are the same or different organic groups that are inactive with respect to isocyanate groups under the reaction conditions, and n is an integer of 2 or greater. The coating composition according to claim 7 , which is a coating for building structures. 9 . A coating film formed by curing the coating composition according to claim 7 .

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