Coating composition, coating film and coated article

Abstract

To provide a coating composition that has excellent pot life and can give a coating layer having excellent chemical resistance, flexibility and appearance.SOLUTION: A coating composition comprises a secondary amine compound (A), and a blocked polyisocyanate composition (B) comprising a blocked polyisocyanate derived from an aliphatic polyisocyanate and one or more blockers.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a coating composition, a coating, and a coated article. [Background technology]

[0002] Polyurea coating compositions are formed from a polyisocyanate composition and an amine compound, and have been used in a wide range of applications, including various types of coatings, flooring materials, and waterproofing materials.

[0003] For example, Patent Document 1 discloses a coating composition containing a polyaspartic acid ester compound, which is a secondary amine compound, and a polyisocyanate composition. Patent Document 1 discloses that a coating film using this coating composition is characterized by excellent chemical resistance, hardness, and weather resistance.

[0004] Patent Document 2 discloses a coating composition containing an aliphatic and / or alicyclic primary polyamine compound and a blocked polyisocyanate composition blocked with an azole compound and / or triazole compound. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018 / 163953 [Patent Document 2] Patent No. 6624469 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the coating compositions proposed in Patent Documents 1 and 2 both react very easily with the curing agent component, and therefore tend to have a short pot life and poor workability.

[0007] The present invention has been made in view of the above circumstances and provides a coating composition that has a good pot life and, when formed into a coating film, is excellent in chemical resistance, flexibility, and appearance. Also provided are a coating film and a coated article using the coating composition. [Means for solving the problem]

[0008] That is, the present invention includes the following aspects. [1] A coating composition comprising: a secondary amine compound (A); and a blocked polyisocyanate composition (B) containing a blocked polyisocyanate derived from an aliphatic polyisocyanate and one or more blocking agents. [2] The coating composition according to [1], wherein the secondary amine compound (A) is an aspartic acid ester compound (A-1) represented by the following general formula (I): [ka] (In general formula (I), X 11 is an n-valent organic group obtained by removing the primary amino group of an n-valent polyamine. 11 and R 12 are the same or different organic groups that are inert to isocyanate groups under reaction conditions. n11 is an integer of 2 or greater. [3] The coating composition according to [1] or [2], further comprising a hydroxyl group-containing resin (C). [4] The coating composition according to any one of [1] to [3], wherein the blocking agent is at least one selected from the group consisting of pyrazole compounds, triazole compounds, imidazole compounds, oxime compounds, and active methylene compounds. [5] The coating composition according to any one of [1] to [4], wherein the blocking agent is one or more selected from the group consisting of pyrazole compounds, triazole compounds, imidazole compounds, and active methylene compounds. [6] The coating composition according to any one of [1] to [5], wherein the molar ratio of amino groups in the secondary amine compound (A) to available isocyanate groups in the blocked polyisocyanate composition (B) is 1 / 10 or more and 10 / 1 or less. [7] A coating film obtained by curing the coating composition according to any one of [1] to [6]. [8] A coated article having the coating film described in [7]. [Effects of the Invention]

[0009] According to the present invention, there is provided a coating composition which has a good pot life and which, when formed into a coating film, has excellent chemical resistance, flexibility, and appearance. It is also possible to provide a coating film and a coated article using the coating composition. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out by appropriately modifying it within the scope of its gist.

[0011] <Paint composition> The coating composition of this embodiment contains a secondary amine compound (A) and a blocked polyisocyanate composition (B) containing a blocked polyisocyanate derived from an aliphatic polyisocyanate and one or more blocking agents. Each of the components of the coating composition of this embodiment will be described in detail below.

[0012] <Secondary amine compound (A)> The coating composition of this embodiment contains a secondary amine compound (A) as a main component. In this embodiment, the secondary amine compound (A) is not particularly limited as long as it contains one or more secondary amino groups in one molecule. From the viewpoint of forming a harder coating film, the secondary amine compound (A) is preferably a compound containing two or more secondary amino groups in one molecule.

[0013] (Aspartic acid ester compound (A-1)) As the secondary amine compound (A) used in this embodiment, an aspartic acid ester compound (A-1) is particularly preferred. The aspartic acid ester compound (A-1) is a compound represented by the following formula (I).

[0014] [ka]

[0015] In the general formula (I), X 11 is an n-valent organic group obtained by removing the primary amino group of an n-valent polyamine. 11 and R 12 are the same or different organic groups that are inert to isocyanate groups under reaction conditions. n11 is an integer of 2 or greater.

[0016] X in formula (I) 11 is not particularly limited, but is preferably an organic group based on either or both of an aliphatic or alicyclic polyamine having no aromatic group, from the viewpoint of suppressing yellowing of the coating film.

[0017] Examples of such organic groups include ethylenediamine, 1,2-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 2,5-diamino-2,5-dimethylhexane, 2,2,4- and / or 2,4,4-trimethyl-1,6-diaminohexane, 1,11-diaminoundecane, 1,12-diaminododecane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 2,4- and and / or 2,6-hexahydrotolylenediamine, 2,4'- and / or 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 2,4,4'-triamino-5-methyldicyclohexylmethane, and n11-valent polyamines selected from the group consisting of organic groups based on polyether polyamines having a number average molecular weight of 148 or more and 6,000 or less and in which primary amino groups are aliphatically bonded.

[0018] Among them, X 11 is preferably an organic group based on 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 2,2,4- and / or 2,4,4-trimethyl-1,6-diaminohexane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 4,4′-diaminodicyclohexylmethane or 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane.

[0019] Also, X 11 is more preferably an organic group based on 4,4'-diaminodicyclohexylmethane or 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane.

[0020] R in formula (I) 11 and R 12 As defined in [1], "inert to isocyanate groups under reaction conditions" means that these groups do not contain Zerewitinoff-active hydrogen-containing groups (CH acidic compounds), such as hydroxyl, amino, or thiol groups.

[0021] R 11and R 12 are each independently preferably an alkyl group having 1 to 10 carbon atoms, more preferably a methyl group, an ethyl group, or a butyl group.

[0022] In formula (I), n11 is preferably an integer of 2 or more and 6 or less, more preferably an integer of 2 or more and 4 or less, and even more preferably 2.

[0023] A preferred aspartic acid ester compound (A-1) is, for example, an aspartic acid ester compound derived from two molecules of aspartic acid having a secondary amino group and one molecule of 4,4'-diaminodicyclohexylmethane.

[0024] The aspartic acid ester compound (A-1) may be a commercially available product. Commercially available aspartic acid ester compounds (A) include, for example, Evonik products under the trade names "Amicure IC-221" (amine value 188 mg KOH / g resin, viscosity 450 mPa·s (representative value measured at 25°C)), "Amicure IC-321" (amine value 190 mg KOH / g resin, viscosity 450 mPa·s (representative value measured at 25°C)), and "Amicure IC-322" (amine value 189 mg KOH / g resin, viscosity 150 mPa·s (representative value measured at 25°C)); and Feiyang products under the trade names "Feispartic F420" (amine value 192 mg KOH / g resin, viscosity 1450 mPa·s (representative value measured at 25°C)) and "Feispartic F520" (amine value 189 mg KOH / g resin, viscosity 1400 mPa·s (representative value measured at 25°C)).

[0025] The above-mentioned aspartic acid ester compounds (A-1) may be used alone or in combination of two or more. In particular, the coating composition of this embodiment preferably contains a combination of two aspartic acid ester compounds (A) with different reactivities, which improves the pot life and the appearance of the resulting coating film.

[0026] The reactivity referred to here means the ease of reaction with a curing agent component (for example, an isocyanate group in a polyisocyanate composition). The reactivity of the aspartic acid ester compound (A) with a curing agent component can be evaluated using the amine value of the aspartic acid ester compound as an index.

[0027] The method for producing the aspartic acid ester compound (A-1) is not particularly limited, but it can be produced, for example, by reacting a primary polyamine represented by the following formula (IV) with a maleic acid ester or a fumaric acid ester represented by the following formula (V).

[0028] X 11 -[NH2]n11 (IV) R 11 OOC-CH=CH-COOR 12 (V) (In the above formula, X 11 , R 11 , R 12 , n11 has the same meaning as that represented by formula (I).

[0029] Suitable polyamines include, but are not limited to, X 11 Examples of the organic group include the diamines mentioned above.

[0030] Suitable maleic acid esters or fumaric acid esters are not particularly limited, but examples thereof include R 11 and R 12 The group defined in R 11 and R 12 The maleic acid ester or fumaric acid ester has the formula:

[0031] Among them, R 11 and R 12 is an alkyl group having 1 to 10 carbon atoms, and dimethyl maleate, diethyl maleate, dibutyl maleate, dimethyl fumarate, diethyl fumarate, or dibutyl fumarate is more preferred.

[0032] The preparation of aspartic acid ester compounds from the starting materials described is preferably carried out at temperatures ranging from 0° C. to 100° C. The starting materials are used in proportions such that there is at least one, and preferably only one, olefinic double bond in each primary amino group.

[0033] If desired, excess starting materials can be removed by distillation after the reaction. The reaction can be carried out in bulk or in the presence of a suitable solvent (such as, but not limited to, methanol, ethanol, propanol, or dioxane, or a mixture of such solvents).

[0034] <Blocked polyisocyanate composition (B)> The coating composition of this embodiment contains a blocked polyisocyanate composition (B) as a curing agent component.

[0035] (Blocked polyisocyanate) The blocked polyisocyanate of this embodiment is derived from an aliphatic polyisocyanate and one or more blocking agents, i.e., the blocked polyisocyanate is obtained by blocking at least a portion of the isocyanate groups in the aliphatic polyisocyanate with a blocking agent.

[0036] [Other functional groups] The blocked polyisocyanate may have one or more functional groups selected from the group consisting of an allophanate group, a uretdione group, an iminooxadiazinedione group, an isocyanurate group, a urethane group, and a biuret group. Of these, from the viewpoint of improving the weather resistance of the coating film, it is preferable that the blocked polyisocyanate has an isocyanurate group.

[0037] [Polyisocyanate] The aliphatic polyisocyanate used in the production of blocked polyisocyanates is a reaction product obtained by reacting multiple monomer compounds having one or more isocyanate groups (-NCO) (hereinafter, sometimes referred to as "isocyanate monomers").

[0038] The isocyanate monomer is preferably an aliphatic diisocyanate monomer having 4 to 30 carbon atoms. Specific examples of the aliphatic diisocyanate monomer include the following. These isocyanate monomers may be used alone or in combination of two or more.

[0039] Examples of the aliphatic diisocyanate monomer include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (hereinafter sometimes referred to as "HDI"), 2,2,4-trimethyl-1,6-diisocyanatohexane, 2,4,4-trimethyl-1,6-hexamethylene diisocyanate, 2-methylpentane-1,5-diisocyanate (MPDI), and lysine diisocyanate (hereinafter sometimes referred to as "LDI").

[0040] The coating composition of the present embodiment may also contain the following aromatic diisocyanates, alicyclic diisocyanates, and triisocyanates.

[0041] Examples of aromatic diisocyanates include diphenylmethane-4,4'-diisocyanate (MDI), 1,5-naphthalene diisocyanate, tolylene diisocyanate (TDI), xylylene diisocyanate, and m-tetramethylxylylene diisocyanate (TMXDI).

[0042] Examples of alicyclic diisocyanates include isophorone diisocyanate (hereinafter sometimes referred to as "IPDI"), 1,3-bis(diisocyanatemethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, diisocyanate norbornane, and di(isocyanatemethyl)norbornane.

[0043] Examples of triisocyanates include 4-isocyanatomethyl-1,8-octamethylene diisocyanate (hereinafter sometimes referred to as "NTI"), 1,3,6-hexamethylene triisocyanate (hereinafter sometimes referred to as "HTI"), bis(2-isocyanatoethyl) 2-isocyanatoglutarate (hereinafter sometimes referred to as "GTI"), and lysine triisocyanate (hereinafter sometimes referred to as "LTI").

[0044] Among these, from the viewpoint of improving the weather resistance of the coating film, it is preferable that the isocyanate monomer contains an aliphatic diisocyanate as an essential component. Furthermore, it is preferable that the other isocyanate monomer is one or more alicyclic diisocyanates. Furthermore, it is even more preferable that the isocyanate monomer is HDI because of its ease of industrial availability.

[0045] As the isocyanate monomer used in the production of polyisocyanate, either an aliphatic diisocyanate or an alicyclic diisocyanate may be used alone or in combination.

[0046] The polyisocyanate is preferably derived from the above-mentioned diisocyanate monomer and polyol A having an average hydroxyl functionality of 3.0 to 8.0. This allows the average number of isocyanate groups in the resulting polyisocyanate to be increased. In the polyisocyanate, urethane groups are formed by the reaction between the hydroxyl groups of polyol A and the isocyanate groups of the diisocyanate monomer.

[0047] The average number of hydroxyl functional groups in polyol A is preferably 3.0 or more and 8.0 or less, more preferably 3 or more and 6 or less, even more preferably 3 or more and 5 or less, and particularly preferably 3 or 4. The average number of hydroxyl functional groups in polyol A referred to here is the number of hydroxyl groups present in one molecule of polyol A.

[0048] From the viewpoint of improving the hardness and strength of the coating film, the number average molecular weight of polyol A is preferably 100 or more and 1,000 or less, preferably 100 or more and 900 or less, more preferably 100 or more and 600 or less, more preferably 100 or more and 570 or less, even more preferably 100 or more and 500 or less, still more preferably 100 or more and 400 or less, particularly preferably 100 or more and 350 or less, and most preferably 100 or more and 250 or less.

[0049] A coating composition containing a blocked polyisocyanate composition (B) using a polyol A having a number-average molecular weight within the above range can be cured even at low temperatures and can form a coating film with particularly high hardness and strength. The number-average molecular weight Mn of polyol A is, for example, the number-average molecular weight measured by GPC using polystyrene as the standard.

[0050] Examples of such polyol A include trimethylolpropane, glycerol, and polycaprolactone polyols derived from trihydric or higher polyhydric alcohols and ε-caprolactone.

[0051] Commercially available polycaprolactone polyols include, for example, Daicel Corporation's "PLACCEL 303" (number average molecular weight 300), "PLACCEL 305" (number average molecular weight 550), "PLACCEL 308" (number average molecular weight 850), and "PLACCEL 309" (number average molecular weight 900).

[0052] (Method for producing aliphatic polyisocyanate) The method for producing the aliphatic polyisocyanate will be described in detail below. Aliphatic polyisocyanates can be obtained, for example, by simultaneously carrying out an allophanate reaction to form an allophanate group, a uretdione reaction to form a uretdione group, an iminooxadiazinedione reaction to form an iminooxadiazinedione group, an isocyanurate reaction to form an isocyanurate group, a urethanization reaction to form a urethane group, and a biuret reaction to form a biuret group in the presence of an excess of isocyanate monomer, and then removing the unreacted isocyanate monomer after the completion of the reactions.

[0053] That is, the aliphatic polyisocyanate obtained by the above reaction is a reaction product in which a plurality of the above-mentioned isocyanate monomers are bonded together, and which has one or more groups selected from the group consisting of an allophanate group, a uretdione group, an iminooxadiazinedione group, an isocyanurate group, a urethane group, and a biuret group.

[0054] Alternatively, the above reactions may be carried out separately and the resulting polyisocyanates may be mixed in a specific ratio. From the viewpoint of easily producing a coating composition, it is preferable to carry out the above reaction at once to obtain a polyisocyanate, but from the viewpoint of freely adjusting the molar ratio of each functional group, it is preferable to produce them separately and then mix them.

[0055] (1) Method for producing allophanate group-containing polyisocyanate The allophanate group-containing polyisocyanate can be obtained by adding an alcohol to an isocyanate monomer and using an allophanate reaction catalyst. The alcohol used to form the allophanate group is preferably an alcohol formed only from carbon, hydrogen and oxygen.

[0056] Specific examples of the alcohol include, but are not limited to, monoalcohols, dialcohols, etc. These alcohols may be used alone or in combination of two or more.

[0057] Examples of monoalcohols include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, and nonanol.

[0058] Examples of the dialcohol include ethylene glycol, 1,3-butanediol, neopentyl glycol, and 2-ethylhexanediol. Among these, the alcohol is preferably a monoalcohol, and more preferably a monoalcohol having a molecular weight of 200 or less.

[0059] The allophanatization reaction catalyst includes, but is not limited to, alkyl carboxylates of tin, lead, zinc, bismuth, zirconium, zirconyl, and the like.

[0060] Examples of tin alkylcarboxylates (organotin compounds) include tin 2-ethylhexanoate and dibutyltin dilaurate.

[0061] Examples of lead alkylcarboxylates (organic lead compounds) include lead 2-ethylhexanoate.

[0062] Examples of zinc alkylcarboxylates (organic zinc compounds) include zinc 2-ethylhexanoate.

[0063] Examples of bismuth alkylcarboxylates include bismuth 2-ethylhexanoate.

[0064] Examples of zirconium alkylcarboxylates include zirconium 2-ethylhexanoate.

[0065] Examples of zirconyl alkylcarboxylates include zirconyl 2-ethylhexanoate, etc. These catalysts can be used alone or in combination of two or more.

[0066] Furthermore, an isocyanurate reaction catalyst described below can also serve as an allophanate reaction catalyst. When an allophanate reaction is carried out using an isocyanurate reaction catalyst described below, an isocyanurate group-containing polyisocyanate (hereinafter, sometimes referred to as an "isocyanurate-type polyisocyanate") is naturally also produced.

[0067] Among these, it is preferable from the viewpoint of economical production to carry out the allophanate formation reaction and the isocyanurate formation reaction using an isocyanurate formation catalyst described below as the allophanate formation reaction catalyst.

[0068] The lower limit of the amount of the allophanate reaction catalyst used is preferably 10 ppm by mass or more, more preferably 20 ppm by mass or more, even more preferably 40 ppm by mass or more, and particularly preferably 80 ppm by mass or more, relative to the mass of the charged isocyanate monomer.

[0069] The upper limit of the amount of the allophanate reaction catalyst used is preferably 1000 ppm by mass or less, more preferably 800 ppm by mass or less, even more preferably 600 ppm by mass or less, and particularly preferably 500 ppm by mass or less, relative to the mass of the charged isocyanate monomer.

[0070] That is, the amount of the allophanate reaction catalyst used is preferably 10 ppm by mass or more and 1000 ppm by mass or less, more preferably 20 ppm by mass or more and 800 ppm by mass or less, even more preferably 40 ppm by mass or more and 600 ppm by mass or less, and particularly preferably 80 ppm by mass or more and 500 ppm by mass or less, relative to the mass of the charged isocyanate monomer.

[0071] The lower limit of the allophanatization reaction temperature is preferably 40°C or higher, more preferably 60°C or higher, even more preferably 80°C or higher, and particularly preferably 100°C or higher.

[0072] The upper limit of the allophanate reaction temperature is preferably 180°C or lower, more preferably 160°C or lower, and even more preferably 140°C or lower.

[0073] That is, the allophanate reaction temperature is preferably 40°C or higher and 180°C or lower, more preferably 60°C or higher and 160°C or lower, even more preferably 80°C or higher and 140°C or lower, and particularly preferably 100°C or higher and 140°C or lower.

[0074] By setting the allophanate reaction temperature to the above lower limit or higher, the reaction rate can be further improved. By setting the allophanate reaction temperature to the above upper limit or lower, coloration of the polyisocyanate tends to be more effectively suppressed.

[0075] (2) Method for producing uretdione group-containing polyisocyanate When a polyisocyanate having a uretdione group is derived from an isocyanate monomer, it can be produced, for example, by polymerizing the isocyanate monomer using a uretdione reaction catalyst or by heat.

[0076] The uretdione-forming reaction catalyst is not particularly limited, but examples thereof include tertiary phosphines such as trialkylphosphine, tris(dialkylamino)phosphine and cycloalkylphosphine, Lewis acids, and the like.

[0077] Examples of trialkylphosphines include tri-n-butylphosphine and tri-n-octylphosphine.

[0078] Examples of tris(dialkylamino)phosphines include tris-(dimethylamino)phosphine.

[0079] Examples of cycloalkylphosphines include cyclohexyl-di-n-hexylphosphine.

[0080] Examples of Lewis acids include boron trifluoride and zinc oxychloride.

[0081] Many of the catalysts for the uretdione formation reaction can also promote the isocyanurate formation reaction at the same time. When a uretdione-forming reaction catalyst is used, it is preferable to add a deactivator for the uretdione-forming reaction catalyst such as phosphoric acid or methyl paratoluenesulfonate to terminate the uretdione-forming reaction when the desired yield is achieved.

[0082] When one or more diisocyanates selected from the group consisting of the aliphatic diisocyanates and the alicyclic diisocyanates are heated without using a uretdione reaction catalyst to obtain a polyisocyanate having uretdione groups, the heating temperature is preferably 120° C. or higher, more preferably 150° C. or higher and 170° C. or lower, and the heating time is preferably 1 hour or longer and 4 hours or shorter.

[0083] (3) Method for producing iminooxadiazinedione group-containing polyisocyanate When an iminooxadiazinedione group-containing polyisocyanate is derived from an isocyanate monomer, an iminooxadiazinedione-forming reaction catalyst is usually used.

[0084] Examples of the iminooxadiazinedione catalyst include those shown in 1) or 2) below.

[0085] 1) (Poly)hydrogen fluoride represented by the general formula M[Fn] or the general formula M[Fn(HF)m] (wherein m and n are integers satisfying the relationship m / n>0. M is an n-charged cation (mixture) or one or more radicals with a total valence of n.)

[0086] 2) A compound comprising a compound represented by the general formula R1-CR'2-C(O)O- or the general formula R2=CR'-C(O)O- and a quaternary ammonium cation or a quaternary phosphonium cation. (In the formula, R1 and R2 each independently represent a linear, branched, or cyclic, saturated or unsaturated perfluoroalkyl group having from 1 to 30 carbon atoms. Each of the multiple R's each independently represents a hydrogen atom, or an alkyl or aryl group having from 1 to 20 carbon atoms which may contain a heteroatom.)

[0087] Specific examples of the compound 1) ((poly)hydrogen fluoride) include tetramethylammonium fluoride hydrate, tetraethylammonium fluoride, and the like.

[0088] Specific examples of the compound 2) include 3,3,3-trifluorocarboxylic acid, 4,4,4,3,3-pentafluorobutanoic acid, 5,5,5,4,4,3,3-heptafluoropentanoic acid, and 3,3-difluoroprop-2-enoic acid.

[0089] Among them, as the iminooxadiazinedione-forming reaction catalyst, 1) is preferred from the viewpoint of easy availability, and 2) is preferred from the viewpoint of safety.

[0090] The lower limit of the amount of the iminooxadiazinedione catalyst used is not particularly limited, but from the viewpoint of reactivity, it is preferably 5 ppm or more, more preferably 10 ppm or more, and even more preferably 20 ppm or more, in terms of mass ratio relative to the raw material isocyanate monomer such as HDI.

[0091] From the viewpoints of suppressing coloration and discoloration of the product and controlling the reaction, the upper limit of the amount of the iminooxadiazinedione catalyst used is preferably 5000 ppm or less, more preferably 2000 ppm or less, and even more preferably 500 ppm or less, by mass ratio relative to the raw material isocyanate monomer such as HDI.

[0092] That is, the amount of the iminooxadiazinedione catalyst used is preferably 5 ppm or more and 5000 ppm or less, more preferably 10 ppm or more and 2000 ppm or less, and even more preferably 20 ppm or more and 500 ppm or less, by mass ratio relative to the raw material isocyanate monomer such as HDI.

[0093] The lower limit of the reaction temperature for the iminooxadiazinedione formation is not particularly limited, but from the viewpoint of the reaction rate, it is preferably 40°C or higher, more preferably 50°C or higher, and even more preferably 60°C or higher.

[0094] The upper limit of the reaction temperature for the iminooxadiazinedione formation is preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 110°C or lower, from the viewpoint of suppressing coloration and discoloration of the product.

[0095] That is, the reaction temperature for the iminooxadiazinedione formation is preferably 40°C or higher and 150°C or lower, more preferably 50°C or higher and 120°C or lower, and even more preferably 60°C or higher and 110°C or lower.

[0096] When the iminooxadiazinedione reaction reaches a desired iminooxadiazinedione group content, the iminooxadiazinedione reaction can be terminated, for example, by adding an acidic compound to the reaction mixture.

[0097] Examples of acidic compounds include phosphoric acid, acidic phosphate esters, sulfuric acid, hydrochloric acid, sulfonic acid compounds, etc. The iminooxadiazinedione-forming reaction catalyst is neutralized by the acidic compound, or inactivated by thermal decomposition or chemical decomposition, etc. After the reaction is stopped, filtration is carried out, if necessary.

[0098] (4) Method for producing isocyanurate group-containing polyisocyanate Examples of catalysts for deriving polyisocyanates containing isocyanurate groups from isocyanate monomers include commonly used isocyanuration reaction catalysts.

[0099] The isocyanurate reaction catalyst is not particularly limited, but is generally preferably a basic catalyst. Specific examples of the isocyanurate reaction catalyst include any of the following 1) to 9).

[0100] 1) Hydroxides of tetraalkylammonium such as tetramethylammonium, tetraethylammonium, and tetrabutylammonium, and organic weak acid salts of the above tetraalkylammonium such as acetate, propionate, octylate, caprate, myristate, and benzoate.

[0101] 2) Hydroxides of aryltrialkylammonium such as benzyltrimethylammonium and trimethylphenylammonium, and organic weak acid salts of the above aryltrialkylammonium such as acetate, propionate, octylate, caprate, myristate, and benzoate.

[0102] 3) Hydroxyalkylammonium hydroxides such as trimethylhydroxyethylammonium, trimethylhydroxypropylammonium, triethylhydroxyethylammonium, and triethylhydroxypropylammonium, and organic weak acid salts such as acetates, propionates, octylates, caprates, myristates, and benzoates of the above hydroxyalkylammoniums.

[0103] 4) Metal salts of tin, zinc, lead, etc. of alkylcarboxylic acids such as acetic acid, propionic acid, caproic acid, octylic acid, capric acid, and myristic acid.

[0104] 5) Metal alcoholates such as sodium and potassium.

[0105] 6) Aminosilyl group-containing compounds such as hexamethylenedisilazane.

[0106] 7) Mannich bases.

[0107] 8) Mixtures of tertiary amines and epoxy compounds.

[0108] 9) Phosphorus compounds such as tributylphosphine.

[0109] Among these, from the viewpoint of reducing the generation of unnecessary by-products, the isocyanuration reaction catalyst is preferably a quaternary ammonium hydroxide or a weak organic acid salt of a quaternary ammonium, and more preferably a tetraalkylammonium hydroxide, a weak organic acid salt of a tetraalkylammonium, an aryltrialkylammonium hydroxide, or a weak organic acid salt of an aryltrialkylammonium.

[0110] The upper limit of the amount of the isocyanurate reaction catalyst used is preferably 1000 ppm by mass or less, more preferably 500 ppm by mass or less, and even more preferably 100 ppm by mass or less, relative to the mass of the charged isocyanate monomer.

[0111] On the other hand, the lower limit of the amount of the isocyanurate reaction catalyst used is not particularly limited, but may be, for example, 10 ppm by mass or more.

[0112] The isocyanurate reaction temperature is preferably 50° C. or higher and 120° C. or lower, and more preferably 60° C. or higher and 90° C. or lower. When the isocyanurate reaction temperature is equal to or lower than the upper limit, coloration of the polyisocyanate tends to be more effectively suppressed.

[0113] Once the desired conversion is achieved, the isocyanuration reaction is stopped by the addition of an acidic compound (eg, phosphoric acid, acidic phosphate ester, etc.). The conversion rate here refers to the ratio of the mass of polyisocyanate produced by the isocyanuration reaction to the mass of the charged isocyanate monomer.

[0114] In order to obtain polyisocyanate, it is necessary to stop the reaction in an early stage. However, since the reaction rate of the isocyanuration reaction is very fast in the early stage, it is difficult to stop the reaction in an early stage. For this reason, the reaction conditions, particularly the amount and method of adding the catalyst, must be carefully selected. For example, a method in which the catalyst is added in portions at regular intervals is recommended as being suitable.

[0115] Therefore, the conversion rate of the isocyanurate reaction to obtain polyisocyanate is preferably 10% or more and 60% or less, more preferably 15% or more and 55% or less, and even more preferably 20% or more and 50% or less.

[0116] By keeping the conversion rate of the isocyanurate reaction at or below the upper limit, the viscosity of the blocked polyisocyanate component can be further reduced. Furthermore, by keeping the conversion rate of the isocyanurate reaction at or above the lower limit, the reaction termination operation can be more easily carried out.

[0117] When deriving a polyisocyanate containing an isocyanurate group, a monohydric to hexahydric alcohol can be used in addition to the above isocyanate monomer.

[0118] Examples of alcohols that can be used include non-polymerizable alcohols and polymerizable alcohols. The term "non-polymerizable alcohol" used herein refers to an alcohol that does not have a polymerizable group. Meanwhile, the term "polymerizable alcohol" refers to an alcohol obtained by polymerizing a monomer that has a polymerizable group and a hydroxyl group.

[0119] Examples of non-polymerizable alcohols include polyhydric alcohols such as monoalcohols, diols, triols, and tetraols.

[0120] Examples of monoalcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, n-pentanol, n-hexanol, n-octanol, n-nonanol, 2-ethylbutanol, 2,2-dimethylhexanol, 2-ethylhexanol, cyclohexanol, methylcyclohexanol, and ethylcyclohexanol.

[0121] Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,2-propanediol, 1,5-pentanediol, and 2-methyl-2,3-butanediol. Examples of the hexanediol include hexanediol, 1,6-hexanediol, 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,3-dimethyl-2,3-butanediol, 2-ethyl-hexanediol, 1,2-octanediol, 1,2-decanediol, 2,2,4-trimethylpentanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-diethyl-1,3-propanediol.

[0122] Examples of triols include glycerin and trimethylolpropane.

[0123] An example of the tetraols is pentaerythritol.

[0124] The polymerizable alcohol is not particularly limited, but examples thereof include polyester polyols, polyether polyols, acrylic polyols, polyolefin polyols, and the like.

[0125] The polyester polyols are not particularly limited, but examples thereof include products obtained by a condensation reaction between a dibasic acid alone or a mixture thereof and a polyhydric alcohol alone or a mixture thereof.

[0126] The dibasic acid is not particularly limited, but examples thereof include at least one dibasic acid selected from the group consisting of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid.

[0127] The polyhydric alcohol is not particularly limited, but examples thereof include at least one polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin.

[0128] Examples of polyester polyols include polycaprolactones obtained by ring-opening polymerization of ε-caprolactone using the above polyhydric alcohols.

[0129] The polyether polyols are not particularly limited, but examples thereof include polyether polyols obtained by adding alkylene oxides, either singly or in mixture, to polyhydric alcohols, either singly or in mixture, using an alkali metal hydroxide or a strongly basic catalyst; polyether polyols obtained by reacting alkylene oxides with polyamine compounds; and so-called polymer polyols obtained by polymerizing acrylamide or the like using the above polyethers as a medium.

[0130] Examples of alkali metals include lithium, sodium, and potassium.

[0131] Examples of the strong basic catalyst include alcoholates and alkylamines.

[0132] Examples of the polyhydric alcohol include the same ones as those exemplified above for the polyester polyols.

[0133] Examples of alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide.

[0134] Examples of polyamine compounds include ethylenediamines.

[0135] The acrylic polyols are not particularly limited, but examples thereof include copolymers of a single or a mixture of an ethylenically unsaturated bond-containing monomer having a hydroxyl group and a single or a mixture of other ethylenically unsaturated bond-containing monomers copolymerizable therewith.

[0136] The ethylenically unsaturated bond-containing monomer having a hydroxyl group is not particularly limited, but examples thereof include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate.

[0137] The other ethylenically unsaturated bond-containing monomer copolymerizable with the ethylenically unsaturated bond-containing monomer having a hydroxyl group is not particularly limited, and examples thereof include acrylic acid esters, methacrylic acid esters, unsaturated carboxylic acids, unsaturated amides, vinyl-based monomers, and vinyl-based monomers having a hydrolyzable silyl group.

[0138] Examples of acrylic acid esters include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, benzyl acrylate, and phenyl acrylate.

[0139] Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, and phenyl methacrylate.

[0140] Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, and itaconic acid.

[0141] Examples of unsaturated amides include acrylamide, methacrylamide, N,N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, maleic acid amide, and maleimide.

[0142] Examples of vinyl monomers include glycidyl methacrylate, styrene, vinyltoluene, vinyl acetate, acrylonitrile, and dibutyl fumarate.

[0143] Examples of vinyl monomers having a hydrolyzable silyl group include vinyltrimethoxysilane, vinylmethyldimethoxysilane, and γ-(meth)acryloxypropyltrimethoxysilane.

[0144] Examples of polyolefin polyols include hydroxyl-terminated polybutadiene and hydrogenated products thereof.

[0145] (5) Method for producing urethane group-containing polyisocyanate When a polyisocyanate containing a urethane group is derived from an isocyanate monomer, it can be produced, for example, by mixing an excess of the isocyanate monomer, the polyol A, and, if necessary, an alcohol other than the polyol A, and, if necessary, adding a urethanization reaction catalyst.

[0146] Examples of the polyol A include the same ones as those exemplified in the above "polyol A".

[0147] Examples of alcohols other than the polyol A include those exemplified in the above "method for producing an isocyanurate group-containing polyisocyanate" except for those exemplified in the above "polyol A".

[0148] The urethanization reaction catalyst is not particularly limited, but examples thereof include tin-based compounds, zinc-based compounds, and amine-based compounds. The urethane reaction temperature is preferably 50°C or higher and 160°C or lower, and more preferably 60°C or higher and 120°C or lower. When the urethanization reaction temperature is equal to or lower than the upper limit, coloration of the polyisocyanate tends to be more effectively suppressed.

[0149] The urethane reaction time is preferably 30 minutes to 4 hours, more preferably 1 hour to 3 hours, and even more preferably 1 hour to 2 hours.

[0150] The molar ratio of the isocyanate groups of the isocyanate monomer to the molar amount of hydroxyl groups of the polyol (and, if necessary, alcohol other than the polyol) is preferably 2 / 1 or more and 50 / 1 or less. When this molar ratio is equal to or more than the above-mentioned lower limit, the viscosity of the polyisocyanate can be made lower. When this molar ratio is equal to or less than the above-mentioned upper limit, the yield of the urethane group-containing polyisocyanate can be made higher.

[0151] (6) Method for producing biuret group-containing polyisocyanate The biuretizing agent for deriving a polyisocyanate containing a biuret group from an isocyanate monomer is not particularly limited, but examples thereof include water, monohydric tertiary alcohols, formic acid, organic primary monoamines, and organic primary diamines.

[0152] The amount of isocyanate groups per mole of biuretizing agent is preferably 6 moles or more, more preferably 10 moles or more, and even more preferably 10 moles or more but 80 moles or less. When the molar amount of isocyanate groups per mole of biuretizing agent is equal to or greater than the above-mentioned lower limit, the viscosity of the polyisocyanate becomes sufficiently low, and when it is equal to or less than the above-mentioned upper limit, the low-temperature curing property of the resin film formed is further improved.

[0153] A solvent may be used in the biuretization reaction, as long as it dissolves the isocyanate monomer and the biuretization agent such as water and forms a homogeneous phase under the reaction conditions.

[0154] Specific examples of the solvent include ethylene glycol-based solvents and phosphoric acid-based solvents.

[0155] Examples of ethylene glycol solvents include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol mono-n-butyl ether acetate, ethylene glycol diacetate, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol di-n-propyl ether, ethylene glycol diisopropyl ether, ethylene glycol di-n-butyl ether, ethylene glycol methyl ethyl ether, ethylene glycol methyl isopropyl ether, ethylene glycol methyl-n-butyl ether, ethylene glycol ethyl-n-propyl ether, ethylene glycol ethyl isopropyl ether, ethylene glycol ethyl-n-butyl ether, ethylene glycol-n-propyl-n-butyl ether, ethylene glycol isopropyl-n-butyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-propyl ether acetate, diethylene glycol monoisopropyl ether acetate, diethylene glycol mono-n-butyl ether acetate, diethylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether, diethylene glycol diisopropyl ether, diethylene glycol di-n-butyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl isopropyl ether, diethylene glycol methyl-n-propyl ether, diethylene glycol methyl-n-butyl ether, diethylene glycol ethyl isopropyl ether, diethylene glycol ethyl-n-propyl ether, diethylene glycol ethyl-n-butyl ether, diethylene glycol-n-propyl-n-butyl ether, and diethylene glycol isopropyl-n-butyl ether.

[0156] Examples of the phosphoric acid solvent include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, and tributyl phosphate.

[0157] These solvents may be used alone or in combination of two or more.

[0158] Of these, the ethylene glycol solvent is preferably ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol diacetate, or diethylene glycol dimethyl ether. As the phosphoric acid-based solvent, trimethyl phosphate or triethyl phosphate is preferred.

[0159] The biuretization reaction temperature is preferably 70° C. or higher and 200° C. or lower, and more preferably 90° C. or higher and 180° C. or lower. By keeping the temperature at or below the upper limit, coloration of the polyisocyanate tends to be more effectively prevented.

[0160] The above-mentioned allophanate formation reaction, uretdione formation reaction, iminooxadiazinedione formation reaction, isocyanurate formation reaction, urethanization reaction, and biuret formation reaction may be carried out sequentially, or some of them may be carried out in parallel.

[0161] After the reaction is completed, unreacted isocyanate monomer can be removed from the reaction mixture by thin film distillation, extraction, or the like to obtain a polyisocyanate.

[0162] Furthermore, an antioxidant or an ultraviolet absorber may be added to the obtained polyisocyanate, for example, for the purpose of suppressing coloration during storage.

[0163] Examples of antioxidants include hindered phenols such as 2,6-di-tert-butyl-p-cresol. Examples of ultraviolet absorbers include benzotriazole and benzophenone. These antioxidants and ultraviolet absorbers may be used alone or in combination of two or more. The amount of these added is preferably 10 ppm by mass or more and 500 ppm by mass or less relative to the mass of polyisocyanate.

[0164] (Average number of isocyanate functional groups in polyisocyanate) The average number of isocyanate functional groups in the polyisocyanate is preferably 2 or more from the viewpoint of improving the low-temperature curing property when formed into a resin film, and from the viewpoint of achieving both the low-temperature curing property when formed into a resin film and compatibility with the secondary amine compound or the hydroxyl group-containing resin, it is more preferably 3 to 20, even more preferably 3.2 to 10, particularly preferably 3.5 to 8, and most preferably 4.2 to 6.

[0165] The average number of isocyanate functional groups of the polyisocyanate can be measured by the method described in the examples below.

[0166] [Blocking agent] Blocking agents used in the production of blocked polyisocyanates include 1) alcohol-based compounds, 2) alkylphenol-based compounds, 3) phenol-based compounds, 4) active methylene-based compounds other than malonic acid esters having a secondary alkyl group and malonic acid esters having a tertiary alkyl group, 5) mercaptan-based compounds, 6) acid amide-based compounds, 7) acid imide-based compounds, 8) imidazole-based compounds, 9) urea-based compounds, 10) oxime-based compounds, 11) amine-based compounds, 12) imide-based compounds, 13) bisulfites, 14) pyrazole-based compounds, 15) triazole-based compounds, etc. More specific examples of blocking agents include the following:

[0167] 1) Examples of alcohol compounds include alcohols such as methanol, ethanol, 2-propanol, n-butanol, sec-butanol, 2-ethyl-1-hexanol, 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol.

[0168] 2) Examples of alkylphenol compounds include mono- and di-alkylphenols having an alkyl group having 4 or more carbon atoms as a substituent. Specific examples of alkylphenol compounds include mono-alkylphenols such as n-propylphenol, iso-propylphenol, n-butylphenol, sec-butylphenol, tert-butylphenol, n-hexylphenol, 2-ethylhexylphenol, n-octylphenol, and n-nonylphenol; and di-n-propylphenol, diisopropylphenol, isopropyl cresol, di-n-butylphenol, di-tert-butylphenol, di-sec-butylphenol, di-n-octylphenol, di-2-ethylhexylphenol, and di-n-nonylphenol.

[0169] 3) Examples of phenolic compounds include phenol, cresol, ethylphenol, styrenated phenol, and hydroxybenzoic acid esters.

[0170] 4) Examples of active methylene compounds include methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, dimethyl malonate, diethyl malonate, di-sec-butyl malonate, di-tert-butyl malonate, di-tert-pentyl malonate, diisopropyl malonate, tert-butylethyl malonate, isopropylethyl malonate, methyl isobutanoylacetate, ethyl isobutanoylacetate, and acetylacetone.

[0171] 5) Examples of mercaptan compounds include butyl mercaptan and dodecyl mercaptan.

[0172] 6) Examples of acid amide compounds include acetanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, and γ-butyrolactam.

[0173] 7) Examples of acid imide compounds include succinimide and maleimide.

[0174] 8) Examples of imidazole compounds include imidazole, 2-methylimidazole, and 2-ethylimidazole.

[0175] 9) Urea compounds include urea, thiourea, ethyleneurea, and the like.

[0176] 10) Examples of oxime compounds include formaldoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, and cyclohexanone oxime.

[0177] 11) Examples of amine compounds include diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, and isopropylethylamine.

[0178] 12) Examples of imine compounds include ethyleneimine and polyethyleneimine.

[0179] 13) Bisulfite compounds include sodium bisulfite.

[0180] 14) Examples of pyrazole compounds include pyrazole, 3-methylpyrazole, and 3,5-dimethylpyrazole.

[0181] 15) Examples of triazole compounds include triazole and 3,5-dimethyl-1,2,4-triazole.

[0182] From the viewpoint of curability, the blocking agent is preferably a pyrazole-based compound, a triazole-based compound, an imidazole-based compound, an oxime-based compound, or an active methylene-based compound, and more preferably a pyrazole-based compound, a triazole-based compound, an imidazole-based compound, an oxime-based compound, or an active methylene-based compound.

[0183] Among the active methylene compounds, di-sec-butyl malonate, di-tert-butyl malonate, di-tert-pentyl malonate, diisopropyl malonate, and tert-butylethyl malonate are preferred from the viewpoint of curability.

[0184] (Other components) The blocked polyisocyanate composition used in the present embodiment may further contain additives such as a solvent in addition to the blocked polyisocyanate.

[0185] Examples of the solvent include 1-methylpyrrolidone, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, 3-methoxy-3-methyl-1-butanol, ethylene glycol diethyl ether, diethylene glycol diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether (DPDM), propylene glycol dimethyl ether, methyl ethyl ketone, acetone, and methyl isopropyl alcohol. Examples of the solvent include butyl ketone, propylene glycol monomethyl ether acetate, ethanol, methanol, isopropanol, 1-propanol, isobutanol, 1-butanol, tert-butanol, 2-ethylhexanol, 2-methyl-2-butanol, cyclohexanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, ethyl acetate, isopropyl acetate, butyl acetate, toluene, xylene, pentane, isopentane, hexane, isohexane, cyclohexane, solvent naphtha, mineral spirits, etc. These solvents may be used alone or in combination of two or more.

[0186] When an active methylene compound is used as a blocking agent, it is particularly preferable to use a monoalcohol as part or all of the solvent from the viewpoint of storage stability.

[0187] <Method for producing blocked polyisocyanate composition> The blocked polyisocyanate composition is not particularly limited, but can be obtained, for example, by reacting the above-mentioned aliphatic polyisocyanate with the above-mentioned blocking agent.

[0188] The blocking reaction between the polyisocyanate and the blocking agent can be carried out regardless of the presence or absence of a solvent, and a blocked polyisocyanate is obtained.

[0189] The blocking agent may be one of the above blocking agents, or two or more of them may be used in a desired ratio. The blocking agent may be completely or partially blocked by a known method, but it is preferable that the blocking agent is completely blocked.

[0190] When all the isocyanate groups are blocked, the ratio (molar number of blocking agent) / (molar number of isocyanate groups in the polyisocyanate composition) is preferably 0.8 to 1.5, more preferably 1.0 to 1.3, in which case excess or unreacted blocking agent remains in the blocked polyisocyanate composition.

[0191] When a solvent is used, it is preferable to use a solvent that is inactive to isocyanate groups.

[0192] When a solvent is used, the content of solids derived from the polyisocyanate and the blocking agent relative to the total mass of the blocked polyisocyanate composition of the present embodiment may usually be from 10 parts by mass to 95 parts by mass, preferably from 20 parts by mass to 80 parts by mass, and more preferably from 30 parts by mass to 70 parts by mass.

[0193] In the blocking reaction, organic metal salts of tin, zinc, lead, etc., tertiary amine compounds, alcoholates of alkali metals such as sodium, etc., may be used as catalysts.

[0194] The amount of catalyst added varies depending on the temperature of the blocking reaction, etc., but is usually from 0.05 to 1.5 parts by mass, preferably from 0.1 to 1.0 part by mass, per 100 parts by mass of polyisocyanate.

[0195] The blocking reaction can generally be carried out at a temperature of −20° C. or higher and 150° C. or lower, preferably at a temperature of 0° C. or higher and 100° C. or lower, and more preferably at a temperature of 10° C. or higher and 70° C. When the temperature of the blocking reaction is equal to or higher than the lower limit, the reaction rate can be increased, and when the temperature is equal to or lower than the upper limit, side reactions can be suppressed.

[0196] After the blocking reaction, a neutralization treatment may be carried out by adding an acidic compound or the like.

[0197] The acidic compound may be an inorganic acid or an organic acid. Examples of inorganic acids include hydrochloric acid, phosphorous acid, and phosphoric acid. Examples of organic acids include methanesulfonic acid, p-toluenesulfonic acid, dioctyl phthalate, and dibutyl phthalate.

[0198] [Amino group / Available isocyanate group] The molar ratio of the amino groups of the secondary amine compound (A) to the available isocyanate groups of the blocked polyisocyanate composition (B) (amino groups / isocyanate groups) is preferably 1 / 10 or more and 10 / 1 or less, more preferably 1 / 5 or more and 5 / 1 or less, even more preferably 1 / 2 or more and 2 / 1 or less, and most preferably 1 / 1.5 or more and 1.5 / 1 or less.

[0199] When the ratio of amino groups to available isocyanate groups is equal to or greater than the above lower limit, the appearance and chemical resistance of the resulting coating film tend to be improved, whereas when the ratio of amino groups to available isocyanate groups is equal to or less than the above upper limit, the pot life of the coating material tends to be improved.

[0200] [Other resin components] The coating composition of this embodiment may further contain a hydroxyl group-containing resin (C) as another resin component (another main component) in addition to the secondary amine compound (A) and the blocked polyisocyanate composition (B).

[0201] ≪Hydroxy group-containing resin (C)≫ The hydroxyl group-containing resin (C) is not particularly limited, but examples thereof include polyols and alkanolamines. These hydroxyl group-containing resins may be contained alone or in combination of two or more. Among these, polyols are preferred as the hydroxyl group-containing resin (C).

[0202] (Polyol) Examples of polyols include polyester polyols, polyether polyols, acrylic polyols, polyolefin polyols, fluorine polyols, polycarbonate polyols, polyurethane polyols, etc. These polyols may be contained alone or in combination of two or more. Among these, polyester polyols and acrylic polyols are preferred as polyols.

[0203] 1. Polyester polyol The polyester polyol can be obtained, for example, by subjecting a dibasic acid, either alone or in a mixture of two or more kinds, to a condensation reaction with a polyhydric alcohol, either alone or in a mixture of two or more kinds.

[0204] Examples of the dibasic acid include succinic acid, adipic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, and other carboxylic acids.

[0205] Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, trimethylolpropane, glycerin, pentaerythritol, 2-methylolpropanediol, and ethoxylated trimethylolpropane.

[0206] Alternatively, for example, polycaprolactones obtained by ring-opening polymerization of lactones such as ε-caprolactone with polyhydric alcohols can also be used as polyester polyols.

[0207] 2. Polyether polyol The polyether polyols are not particularly limited, but examples thereof include the following (1) to (3).

[0208] (1) Polyether polyols obtained by random or block addition of a single or mixture of alkylene oxides to a single or mixture of polyhydric hydroxy compounds using a catalyst.

[0209] Examples of the catalyst include hydroxides (lithium, sodium, potassium, etc.), strongly basic catalysts (alcoholates, alkylamines, etc.), and composite metal cyanide complexes (metalloporphyrins, zinc hexacyanocobaltate complexes, etc.). Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide.

[0210] (2) Polyether polyols obtained by reacting a polyamine compound with an alkylene oxide. Examples of the polyamine compound include ethylenediamines. Examples of the alkylene oxide include the same as those exemplified in (1).

[0211] (3) Polymer polyols obtained by polymerizing acrylamide or the like using the polyether polyols obtained in (1) or (2) as a medium.

[0212] Examples of the polyvalent hydroxy compound include the following compounds (i) to (vi).

[0213] (i) Diglycerin, ditrimethylolpropane, pentaerythritol, dipentaerythritol, etc.

[0214] (ii) Sugar alcohol compounds such as erythritol, D-threitol, L-arabinitol, ribitol, xylitol, sorbitol, mannitol, galactitol, and rhamnitol.

[0215] (iii) Monosaccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, and ribonucleotides.

[0216] (iv) Disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, and melibiose.

[0217] (v) Trisaccharides such as raffinose, gentianose, and melezitose.

[0218] (vi) Tetrasaccharides such as stachyose.

[0219] 3. Acrylic polyol The acrylic polyol is not particularly limited, but examples thereof include those obtained by copolymerizing a single or a mixture of an ethylenically unsaturated bond-containing monomer having a hydroxy group with a single or a mixture of other ethylenically unsaturated bond-containing monomers copolymerizable therewith.

[0220] The ethylenically unsaturated bond-containing monomer having a hydroxy group is not particularly limited, but examples thereof include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. These may be used alone or in combination of two or more. Among these, hydroxyethyl acrylate or hydroxyethyl methacrylate is preferred.

[0221] Examples of other ethylenically unsaturated bond-containing monomers copolymerizable with the above-mentioned monomers include the following (1) to (6), which may be used alone or in combination of two or more.

[0222] (1) Acrylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, benzyl acrylate, and phenyl acrylate.

[0223] (2) Methacrylate esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, and phenyl methacrylate.

[0224] (3) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid.

[0225] (4) Unsaturated amides such as acrylamide, methacrylamide, N,N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, maleic acid amide, and maleimide.

[0226] (5) Vinyl monomers such as glycidyl methacrylate, styrene, vinyl toluene, vinyl acetate, acrylonitrile, and dibutyl fumarate.

[0227] (6) Vinyl monomers having a hydrolyzable silyl group, such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, and γ-(meth)acryloxypropyltrimethoxysilane.

[0228] 4. Polyolefin polyol The polyolefin polyol is not particularly limited, but examples thereof include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.

[0229] The number of hydroxyl groups statistically possessed by one molecule of the polyol (hereinafter, sometimes referred to as the "average number of hydroxyl groups") is preferably at least 2. When the average number of hydroxyl groups of the polyol is at least 2, it tends to be possible to further suppress a decrease in the crosslink density of the coating film obtained by curing the one-component coating composition of the present embodiment.

[0230] 5. Fluoropolyol In this specification, the term "fluoropolyol" refers to a polyol containing fluorine in the molecule. Specific examples of the fluoropolyol include copolymers of fluoroolefins, cyclovinyl ethers, hydroxyalkyl vinyl ethers, and monocarboxylic acid vinyl esters, as disclosed in JP-A-57-34107 and JP-A-61-275311.

[0231] 6. Polycarbonate polyol The polycarbonate polyols are not particularly limited, but examples thereof include the following (1) to (4). (1) Dialkyl carbonates such as dimethyl carbonate. (2) Alkylene carbonates such as ethylene carbonate. (3) Diaryl carbonates such as diphenyl carbonate. (4) A compound obtained by polycondensation of low molecular weight carbonate compounds such as those described in (1) to (3) above.

[0232] 7. Polyurethane polyol The polyurethane polyol is not particularly limited, but can be obtained, for example, by reacting a polyol not containing a carboxy group with an isocyanate component in a conventional manner.

[0233] Examples of the polyol not containing a carboxy group include low molecular weight ones such as ethylene glycol and propylene glycol, and high molecular weight ones such as acrylic polyol, polyester polyol and polyether polyol.

[0234] (hydroxyl value of polyol) The hydroxyl value of the polyol per resin is not particularly limited, but is preferably 10 mg KOH / g resin or more and 300 mg KOH / g resin or less.

[0235] When the hydroxyl value per resin is equal to or greater than the lower limit, a decrease in crosslink density is suppressed, and the desired physical properties tend to be more fully achieved. When the hydroxyl value per resin is equal to or less than the upper limit, an excessive increase in crosslink density is suppressed, and the mechanical properties of the coating film obtained by curing the one-component coating composition of this embodiment tend to be further improved.

[0236] The hydroxyl value of the polyol can be measured in accordance with JIS K1557.

[0237] (Hydroxyl groups / Available isocyanate groups) In the coating composition of this embodiment, when a polyol is contained, the molar ratio of hydroxyl groups of the polyol to the available isocyanate groups of the polyisocyanate composition (B) (hydroxyl groups / isocyanate groups) is preferably 1 / 10 or more and 10 / 1 or less.

[0238] (alkanolamines) As used herein, the term "alkanolamine" refers to a compound having an amino group and a hydroxyl group in one molecule.

[0239] Specific examples of alkanolamines include monoethanolamine, diethanolamine, aminoethylethanolamine, N-(2-hydroxypropyl)ethylenediamine, mono-, di-(n- or iso-)propanolamine, ethylene glycol-bis-propylamine, neopentanolamine, and methylethanolamine.

[0240] (Other ingredients) The coating composition of the present embodiment may further contain an existing melamine resin, epoxy resin, or polyurethane resin, as needed.

[0241] In addition, when the above-mentioned polyol has a carboxy group, an oxazoline group-containing compound and a carbodiimide group-containing compound can be blended. In addition, when the above-mentioned polyol has a carbonyl group, a hydrazide group-containing compound and a semicarbazide group-containing compound can be blended. These compounds may be blended alone or in combination of two or more.

[0242] The coating composition of this embodiment preferably further contains a surface conditioner as an additive, since this provides a coating film with a superior appearance. The type of surface conditioner is not particularly limited, and examples include silicone-based and acrylic-based surface conditioners.

[0243] The content of the surface conditioner is preferably 0.05% by mass or more and 5% by mass or less relative to the resin content of the polyaspartic paint composition. By having the content of the surface conditioner equal to or greater than the above-mentioned lower limit, the appearance of the formed coating film can be further improved. On the other hand, by having the content of the surface conditioner equal to or less than the above-mentioned upper limit, the formed coating film can have better cissing resistance, recoatability, and stain resistance.

[0244] 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, and BYK-3760 (manufactured by BYK); Disparlon 1711EF, Disparlon 1761, Disparlon LS-001, Disparlon LS-050, Disparlon LS-280, Disparlon LS-460, and Disparlon LS-480 (manufactured by Kusumoto Chemicals Co., Ltd.); and Tego Flow 425, Tego Glide 100, Tego Glide 110, Tego Glide 130, Tego Glide 406, Tego Glide 420, Tego Glide 432, Tego Glide 435, Tego Glide 440, Tego Glide 450, Tego Glide 482, Tego Glide 485, Tego Glide ZG400, Tego wet KL245, Tego wet 250, Tego wet 260, Tego wet 265, Tego wet 270, Tego wet 280 (manufactured by Evonic Tego Chemie), etc. These may be used alone or in combination of two or more.

[0245] The acrylic surface conditioner may be a commercially available product, such as BYK-350, BYK-354, BYK-355, BYK-356, BYK-358N, BYK-361N, BYK-392, BYK-394, or BYK-3441 (manufactured by BYK); Disparlon LF-1983, Disparlon LF-1984, LF-1985, Disparlon UVX-35, or Disparlon UVX-36 (manufactured by Kusumoto Chemicals Co., Ltd.); Tego Flow 300, Tego Flow 370, Tego Flow ATF2, or Tego Flow ZFS460. These may be used alone or in combination of two or more.

[0246] As the other types of surface conditioners described above, commercially available products can be used, such as BYK-399, BYK-3440, BYK-3550, BYK-3560, BYK-3565, BYK-SILCLEAN 3700, BYK-SILCLEAN 3701, and 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, and Disparlon LHP-96 (manufactured by Kusumoto Chemicals Co., Ltd.). These may be used alone or in combination of two or more.

[0247] The coating composition of this embodiment preferably further contains an antifoaming, antifoaming, or defoaming agent as an additive, since this results in a more excellent appearance when formed into a coating film. The type of antifoaming, antifoaming, or defoaming agent is not particularly limited, and examples include silicone-based and polymer-based agents.

[0248] The content of the antifoaming, antifoaming, and defoaming agent is preferably 0.05% by mass or more and 5% by mass or less relative to the resin content of the paint composition. Having the content of the antifoaming, antifoaming, and defoaming agent at or above the lower limit above improves workability during blending and stirring, and can also improve the appearance of the resulting paint film. On the other hand, having the content of the antifoaming, antifoaming, and defoaming agent at or below the upper limit above improves the crater resistance, recoatability, and stain resistance of the resulting paint film.

[0249] As the silicone-based antifoaming / foam suppressing / defoaming agent, commercially available products can be used, such as BYK-063, BYK-065, BYK-066N, BYK-067A, BYK-077, BYK-081, and BYK-1799 (manufactured by BYK); Disparlon 1930N, Disparlon 1934, and 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, and Tego Foamex N (manufactured by Evonic Tego Chemie). These may be used alone or in combination of two or more.

[0250] Commercially available polymeric antifoaming / foam suppressing / defoaming agents 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-890EF, Disparlon OX-900HF, Disparlon OX-910HF, Disparlon OX-950HF, Disparlon OX-97EF, Disparlon OX-980EF, Disparlon OX-990EF, Disparlon OX-1000HF, Disparlon OX-1010HF, Disparlon OX-1020HF, Disparlon OX-1030HF, Disparlon OX-1040HF, Disparlon OX-1050HF, Disparlon OX-1060HF, Disparlon OX-1070EF, Disparlon OX-1080EF, Disparlon OX-1090EF, Disparlon OX-1100HF, Disparlon OX-1110HF, Disparlon OX-1120HF, Disparlon OX-1130HF, Disparlon OX-1140HF, Disparlon OX-1150HF, Disparlon OX-1160EF, Disparlon OX-1170EF, Disparlon OX- X-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 Chemicals Co., Ltd.); Tego Airex 910, Tego Airex 920, Tego Airex 936, Tego Airex 944, Tego Airex 955 (manufactured by Evonic Tego Chemie), and the like. These may be used alone or in combination of two or more.

[0251] As the other types of defoaming / foam suppressing / defoaming agents described above, commercially available products can be used, such as BYK-088 and BYK-141 (manufactured by BYK), Disparlon OX-66EF and Disparlon OX-715 (manufactured by Kusumoto Chemicals Co., Ltd.), Tego Airex 940, Tego Airex 945, Tego Airex 950 and Tego Airex 986 (manufactured by Evonic Tego Chemie), etc. These may be used alone or in combination of two or more.

[0252] <Method of manufacturing the coating composition> The coating composition of this embodiment can be obtained by mixing the secondary amine compound (A) with the hydroxyl-containing resin (C) and other components, if necessary, to obtain a mixture, and then adding the blocked polyisocyanate composition (B), which is a curing agent component, to the mixture and mixing them using a known method, with or without a solvent.

[0253] <Application> The coating composition of the present embodiment is suitably used as a primer, intermediate coat, or top coat on metals such as steel plates and surface-treated steel plates, plastics, inorganic materials such as ceramics, glass, and concrete by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, immersion, roller coating, brush coating, or the like.

[0254] The coating composition of the present embodiment is suitably used to impart cosmetic properties, weather resistance, acid resistance, rust prevention, chipping resistance, adhesion, etc. to pre-coated metals including rust-resistant steel plates, painted parts of automobiles, painted parts of plastics, etc.

[0255] The coating composition of this embodiment is also useful as an adhesive, pressure sensitive adhesive, elastomer, foam, surface treatment agent, and the like.

[0256] <Coating film> The coating film of this embodiment is obtained by curing the coating composition described above. The coating film of this embodiment is excellent in appearance, chemical resistance, impact resistance, and abrasion resistance. The coating film of this embodiment is obtained by applying the coating composition described above using a known method such as roll coating, curtain flow coating, spray coating, bell coating, or electrostatic coating, and then curing it through a baking process.

[0257] <Painted items> The coated article of this embodiment is provided with the coating film described above. By providing the coated article of this embodiment with the coating film described above, the coated article has excellent appearance, chemical resistance, impact resistance, and abrasion resistance. [Example]

[0258] The present embodiment will be described in more detail below with reference to examples, but the present embodiment is not limited to these examples. In the following, Examples 1, 2 and 5 will be referred to as Reference Example 1, Reference Example 2 and Reference Example 5, respectively.

[0259] The methods for measuring various physical properties and evaluation methods are explained below. Unless otherwise specified, "parts" and "%" mean "parts by mass" and "% by mass".

[0260] <Methods for measuring physical properties> [Physical Properties 1] (NCO content (mass%)) The NCO content (isocyanate content, % by mass) of the polyisocyanate (b) that is the raw material of the blocked polyisocyanate composition (B) was measured as follows.

[0261] 1 g to 3 g of the polyisocyanate (b) produced in the Production Example was precisely weighed (W g) into an Erlenmeyer flask, and 20 mL of toluene was added to completely dissolve the polyisocyanate.

[0262] Then, 10 mL of a 2N solution of di-n-butylamine in toluene was added, and after thorough mixing, the mixture was left at room temperature for 15 minutes. Further, 70 mL of isopropyl alcohol was added to the solution, and the mixture was thoroughly mixed.

[0263] This solution was titrated with a 1N hydrochloric acid solution (factor F) using an indicator to obtain a titration value V2 mL. A similar titration operation was performed without using polyisocyanate to obtain a titration value V1 mL. From the obtained titration values ​​V2 mL and V1 mL, the NCO content (mass%) of polyisocyanate (b) was calculated according to the following formula.

[0264] (NCO content (mass%))=(V1-V2)×F×42 / (W×1000)×100

[0265] [Physical Properties 2] (Viscosity (mPa.s)) The viscosity of the coating composition of polyisocyanate (b), which is the raw material of blocked polyisocyanate composition (B), was measured at 25°C using an E-type viscometer (product name: RE-85R, manufactured by Toki Sangyo Co., Ltd.). A standard rotor (1°34' x R24) was used for the measurement. The rotation speed was set as follows:

[0266] (Rotation speed) 100 rpm (less than 128 mPa·s) 50 rpm (128 mPa·s or more and less than 256 mPa·s) 20 rpm (256 mPa·s or more and less than 640 mPa·s) 10 rpm (640 mPa·s or more and less than 1280 mPa·s) 5 rpm (1280 mPa·s or more and less than 2560 mPa·s) 2.5 rpm (2560 mPa·s or more and less than 5120 mPa·s) 1.0 rpm (5120 mPa s or more and less than 10240 mPa s) 0.5 rpm (10240 mPa·s or more but less than 20480 mPa·s)

[0267] [Physical Properties 3] (number average molecular weight) The number average molecular weight of polyisocyanate (b), which is a raw material of blocked polyisocyanate composition (B), was determined as the number average molecular weight based on polystyrene by gel permeation chromatography (hereinafter abbreviated as "GPC") using the following equipment. The measurement conditions are as follows:

[0268] (Measurement conditions) Equipment: Tosoh Corporation "HLC-8120GPC" (product name) Column: Tosoh Corporation "TSKgel SuperH1000" (product name) x 1 "TSKgel SuperH2000" (product name) x 1 "TSKgel SuperH3000" (product name) x 1 Carrier: Tetrahydrofuran Detector: differential refractometer

[0269] [Physical Properties 4] (average number of isocyanate groups) The average number of isocyanate groups in polyisocyanate (b), which is a raw material for blocked polyisocyanate composition (B), was calculated based on the following formula using the NCO content obtained in Property 1 and the number average molecular weight obtained in Property 3.

[0270] (Average number of isocyanate groups) = (Number average molecular weight) × (NCO content) / 100 / 42

[0271] [Physical Properties 5] (Diisocyanate monomer mass concentration (mass%)) The diisocyanate mass concentration of polyisocyanate (b), the raw material for blocked polyisocyanate composition (B), was determined as follows: First, a 20 mL sample bottle was placed on a digital balance, and approximately 1 g of the sample was precisely weighed out. Next, 0.03 g to 0.04 g of nitrobenzene (internal standard solution) was added and precisely weighed out. Finally, approximately 9 mL of ethyl acetate was added, and the bottle was tightly capped and thoroughly mixed to prepare the sample. The prepared sample was analyzed by gas chromatography under the following conditions and quantified.

[0272] (Measurement conditions) Equipment: “GC-8A” manufactured by SHIMADZU Column: "Silicone OV-17" manufactured by Shinwa Chemical Industry Co., Ltd. Column oven temperature: 120°C Injection / detector temperature: 160°C

[0273] <Evaluation method> [Rating 1] (pot life) The viscosity of each coating composition 5 minutes after preparation and after 3 days at 50°C was measured in the same manner as in the method described in Physical Properties 2 above, and the pot life was evaluated using the following criteria in terms of the value (viscosity after 3 days at 50°C) / (viscosity from preparation).

[0274] (Evaluation criteria) ◎: 0.8 or more and less than 1.2 ○: 0.6 or more and less than 0.8, or 1.2 or more and less than 1.5 △: 0.3 or more and less than 0.6, or 1.5 or more and less than 2.0 ×: gelation, measurement impossible

[0275] [Rating 2] (Coating appearance) Five minutes after preparation, each coating composition was applied to a glass plate with an applicator to a dry film thickness of 80 μm to 100 μm, then baked at 140°C for 30 minutes and dried at room temperature for 1 day. The appearance of the coating was then evaluated visually according to the following criteria.

[0276] (Evaluation criteria) ◎: The film is transparent and the fluorescent light transfers clearly. ○: The film is transparent, and the fluorescent light transfers slightly wavy. △: The film is slightly cloudy and the fluorescent light transfer is slightly wavy ×: The film is cloudy and the fluorescent light transfers wavy

[0277] [Rating 3] (chemical resistance) Five minutes after preparation, each coating composition was applied to a glass plate with an applicator to a dry film thickness of 80 μm to 100 μm. The film was then baked at 140°C for 30 minutes to obtain a cured coating. A cotton ball soaked in isopropyl alcohol was then placed on the coating for 1 minute, after which the appearance of the coating was visually inspected and the chemical resistance was evaluated according to the following criteria.

[0278] (Evaluation criteria) ○: No change in appearance of the coating film △: Slight change in appearance of coating film ×: Change in appearance of coating film

[0279] [Rating 4] (Bending resistance) Each coating composition was applied to a steel plate with an applicator to a dry film thickness of 80 μm to 100 μm, and then baked at 140° C. for 30 minutes to obtain a cured coating film. Thereafter, the polarity resistance was measured in accordance with JIS-K-5600-5-1 (flexural resistance (cylindrical mandrel method)). A mandrel with a diameter of 3 mm was used, and the condition of the coating film after the test was observed, and the flex resistance was evaluated according to the following criteria.

[0280] (Evaluation criteria) ○: No peeling or cracking of the coating film was observed. △: There is cracking in the bent part of the coating film. ×: Cracks or peeling was observed on the front surface of the bent portion of the coating film.

[0281] <Production of Polyisocyanate (P)> [Manufacturing Example 1] (Production of Polyisocyanate P-1) A four-neck flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was conditioned under a nitrogen atmosphere. 100 parts by weight of HDI was charged, and the reactor temperature was maintained at 60°C while stirring. 0.15 parts by weight of a solution of tetrabutylammonium acetate, an isocyanuration catalyst, diluted to 10% by weight with 2-ethyl-1-hexanol was added to the flask. The isocyanuration reaction was initiated. When the NCO content of the reaction solution reached 38.7% by weight, phosphoric acid was added to terminate the reaction. The reaction solution was then maintained at 90°C for 1 hour. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. Polyisocyanate P-1 was obtained, with an NCO content of 21.8% by weight, a viscosity of 2600 mPa·s at 25°C, a number-average molecular weight of 660, an average number of isocyanate groups of 3.4, and an HDI monomer mass concentration of 0.1% by weight.

[0282] [Manufacturing Example 2] (Production of Polyisocyanate P-2) A four-neck flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet, and dropping funnel was purged with nitrogen and charged with 100 parts by mass of HDI and 7 parts of a polyester polyol derived from a trihydric alcohol and ε-caprolactone (Daicel Corporation, trade name "Placcel 303"). The temperature inside the reactor was maintained at 90°C for 1 hour while stirring, allowing for a urethane reaction. The temperature inside the reactor was then maintained at 60°C, and the isocyanuration catalyst trimethyl-2-methyl-2-hydroxyethylammonium hydroxide was added. When the NCO content of the reaction solution reached 34.6% by mass, phosphoric acid was added to terminate the reaction. The cooled reaction solution was filtered, and unreacted HDI was removed using a thin-film evaporator. The number-average molecular weight of the reaction product was measured by GPC, and the isocyanate content was measured by titration to confirm the formation of polyisocyanate. The viscosity of the obtained polyisocyanate P-2 at 25°C was 12,000 mPa·s, the isocyanate content was 18.6%, the number average molecular weight was 1,200, and the average number of isocyanate groups was 5.3.

[0283] <Production of Blocked Polyisocyanate (B)> [Manufacturing Example 3] (Production of Blocked Polyisocyanate B-1) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts of polyisocyanate P-1 and 64 parts of dipropylene glycol dimethyl ether under a nitrogen stream, and 50 parts of 3,5-dimethylpyrazole (100% by mole based on the isocyanate (NCO) groups) was added thereto, followed by a reaction at 80°C for 1 hour. After confirming that the NCO groups had disappeared, blocked polyisocyanate component B-1 was obtained. The resulting blocked polyisocyanate component B-1 had an effective NCO group content of 10.1% and a non-volatile content of 70%.

[0284] [Manufacturing Example 4] (Production of Blocked Polyisocyanate B-2) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts of polyisocyanate P-2 under a nitrogen stream, and 95 parts of dipropylene glycol dimethyl ether and 42.5 parts of 3,5-dimethylpyrazole (100% by mole relative to the isocyanate (NCO) groups) were added thereto, followed by a reaction at 80°C for 1 hour. After confirming that the NCO groups had disappeared, blocked polyisocyanate component B-2 was obtained. The resulting blocked polyisocyanate component B-2 had an effective NCO group content of 7.8% and a non-volatile content of 60%.

[0285] [Manufacturing Example 5] (Production of Blocked Polyisocyanate B-3) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts of polyisocyanate P-1 and 64 parts of dipropylene glycol dimethyl ether under a nitrogen stream, and 55 parts of 2-ethylimidazole (110% by mole based on the isocyanate (NCO) groups) was added thereto, followed by a reaction at 50°C for 1 hour. After confirming that the NCO groups had disappeared, blocked polyisocyanate component B-3 was obtained. The resulting blocked polyisocyanate component B-3 had an effective NCO group content of 9.9% and a non-volatile content of 70%.

[0286] [Manufacturing Example 6] (Production of Blocked Polyisocyanate B-4) A four-neck flask equipped with a thermometer, stirring blade, and reflux condenser was charged with 100 parts of polyisocyanate P-2 and 62.3 parts of dipropylene glycol dimethyl ether under a nitrogen stream. 88 parts of diisopropyl malonate (105 mol% relative to the isocyanate (NCO) groups) and 0.8 parts of a methanol solution containing 28% by weight of sodium methylate (0.224 parts as sodium methylate) relative to the total weight of the solution were added at room temperature and reacted at 60°C for 4 hours. Subsequently, 56 parts of isobutanol was added, and the reaction was continued for another 2 hours at 60°C to obtain blocked polyisocyanate component B-4. The resulting blocked polyisocyanate component B-4 had an effective NCO group content of 7.1% and a nonvolatile content of 60%.

[0287] <Production of Coating Composition> [Example 1] (Production of Coating Composition C-a1) Aspartic acid ester compounds (trade name "Feispartic F420" manufactured by Feiyang Co., Ltd., amine value 192 mg KOH / g resin, viscosity 1,450 mPa s (typical value measured at 25°C)) and (trade name "Feispartic F520" manufactured by Feiyang Co., Ltd., amine value 189 mg KOH / g resin, viscosity 1,400 mPa s (typical value measured at 25°C)), a silicone-based surface conditioner (trade name "Tego wet 250" manufactured by Evonik Co., Ltd.), an acrylic-based surface conditioner (trade name "BYK-361N" manufactured by BYK Co., Ltd.), a polymer-based defoamer (trade name "Tego Airex 944" manufactured by Evonik Co., Ltd.), and a dehydrating agent (trade name "Molecular sieves 4A-Powder" manufactured by Union Showa Co., Ltd.) were blended in advance in the amounts shown in Table 1 to obtain a mixture. The resulting mixture was mixed with the blocked polyisocyanate composition B-1 in the amounts shown in Table 1 so that the molar ratio of the amino groups of the aspartic acid ester compound (D) to the isocyanate groups of the blocked polyisocyanate composition B-1 was 1 / 1, thereby obtaining a coating composition C-a1.

[0288] [Examples 2 to 5 and Comparative Examples 1 and 2] (Production of coating compositions C-a2 to C-a5 and C-b1 to C-b2) Each coating composition was produced in the same manner as in Example 1, except that the ingredients were blended in the proportions shown in Table 1.

[0289] The compounds shown in Table 1 by their abbreviations are as follows:

[0290] (Aspartic acid ester compound (D)) D-1: Aspartic acid ester compound, trade name "Feispartic F420", manufactured by Feiyang Co., Ltd., amine value 192 mg KOH / g resin, viscosity 1450 mPa.s (representative value measured at 25°C). D-2: Aspartic acid ester compound, trade name "Feispartic F520", manufactured by Feiyang Co., Ltd., amine value 189 mg KOH / g resin, viscosity 1400 mPa.s (representative value measured at 25°C).

[0291] (Primary amine compounds) D-3: 4,4'-methylenebis(cyclohexylamine), trade name "Amicure PACM", manufactured by Air Products Japan Co., Ltd., amine value 534 mg KOH / g

[0292] (Acrylic polyol (E)) E-1: Acrylic polyol, product name "Setalux 1767", manufactured by Allnex, OH 4.5% by mass / g of resin

[0293] Each of the resulting coating compositions was evaluated using the methods described above, and the results are shown in Table 1.

[0294] [Table 1] [Industrial Applicability]

[0295] The coating composition of this embodiment can provide a coating composition that has good long-term storage stability and, when formed into a coating film, has excellent chemical resistance. The coating composition of this embodiment is suitable for use as a primer, intermediate coat, or top coat on materials such as metals, plastics, and inorganic materials. The coating composition of this embodiment is suitable for imparting cosmetic properties, weather resistance, acid resistance, rust prevention, chipping resistance, adhesion, and the like to pre-coated metals including rust-resistant steel plates, painted parts of automobiles, painted parts of plastics, and the like. The coating composition of this embodiment is also useful as a urethane raw material for adhesives, pressure-sensitive adhesives, elastomers, foams, surface treatment agents, and the like.

Claims

1. a secondary amine compound (A); and (B) a blocked polyisocyanate composition comprising a blocked polyisocyanate derived from an aliphatic polyisocyanate and one or more blocking agents, The secondary amine compound (A) is an aspartic acid ester compound (A-1) represented by the following general formula (I): A coating composition wherein the blocking agent is an imidazole compound or an active methylene compound. 【Chemistry 1】 (In general formula (I), X 11 represents an n-valent organic group obtained by removing a primary amino group from an n11-valent polyamine. R 11 and R 12 represent the same or different organic groups that are inert to isocyanate groups under reaction conditions. n11 represents an integer of 2 or greater.)

2. The coating composition according to claim 1, further comprising a hydroxyl group-containing resin (C).

3. 3. The coating composition according to claim 1, wherein the molar ratio of amino groups in the secondary amine compound (A) to available isocyanate groups in the blocked polyisocyanate composition (B) is 1 / 10 or more and 10 / 1 or less.

4. A coating film obtained by curing the coating composition according to any one of claims 1 to 3.

5. A coated article comprising the coating film of claim 4.

Images