JP2017052944A - Block polyisocyanate composition, one-liquid type coating composition, coated film and coated article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a block polyisocyanate composition maintaining low temperature curability, excellent in adhesiveness with an upper layer coated film when laminating a coated film and excellent in compatibility with polyol.SOLUTION: There is provided a block polyisocyanate composition containing block polyisocyanate obtained from polyisocyanate derived from at least one kind of diisocyanate selected from a group consisting of aliphatic diisocyanate and alicyclic diisocyanate and a blocking agent, where the blocking agent contains at least one kind selected from a group consisting of a malonic acid diester compound having a predetermined structure and a β ketoester compound having a predetermined structure and molar ratio of the predetermined keto body structure and total of the predetermined keto body structure to the predetermined enol body structure and total of the predetermined enol body structure is 75/25 to 97/3.SELECTED DRAWING: None

Description

  The present invention relates to a block polyisocyanate composition, a one-component coating composition, a coating film, and a coated article.

  The polyisocyanate composition is widely used for baking coating as a heat-crosslinking type curing agent together with a melamine curing agent. In recent years, it has been pointed out that formalin is generated when a melamine-based curing agent is used, and from the viewpoints of the global environment, safety, hygiene, etc., polyisocyanates blocked with blocking agents (block polyisocyanates) have attracted attention. Yes.

  Conventionally, oximes, phenols, alcohols, and lactams are known as blocking agents for blocked polyisocyanates.

  As a block polyisocyanate capable of forming a crosslinked coating film at a relatively low temperature, a pyrazole-based block polyisocyanate composition (for example, see Patent Document 1), an aliphatic secondary amine-based block polyisocyanate composition (for example, Patent Document 2) is disclosed.

  In addition, as the block polyisocyanate composition capable of further reducing the baking temperature, a block polyisocyanate composition containing malonic acid diester as a blocking agent (for example, see Patent Document 3), diethyl malonate and ethyl acetoacetate A block polyisocyanate composition using, as a blocking agent (see, for example, Patent Documents 4 and 5) has been proposed.

European Patent Application Publication No. 159117 JP 59-4658 Gazette JP 57-121065 A JP-A-8-225630 JP-A-9-255915

  However, since the block polyisocyanate composition formed using the conventional blocking agent generally requires a high baking temperature of 140 ° C. or higher, the energy cost is very high. Moreover, there is a limitation that a block polyisocyanate composition that requires high-temperature baking cannot be used for processing into a plastic having low heat resistance.

  In the block polyisocyanate composition described in Patent Documents 1 and 2, a baking temperature of about 120 ° C. is required, and further reduction in the baking temperature is desired.

  In applications such as painting of new automobiles, a coating layer such as a clear layer may be further laminated on a coating layer using a conventional block polyisocyanate composition. As a block polyisocyanate composition used in such a case, a block polyisocyanate composition capable of forming a crosslinked coating film at a temperature of 100 ° C. or less and having good adhesion when laminated is desired.

  On the other hand, the block polyisocyanate compositions as described in Patent Documents 3, 4, and 5 can form a crosslinked coating film at a temperature of 100 ° C. or lower, but these block polyisocyanate compositions were used. There is a further problem in adhesion when a coating film is further laminated on the coating layer. In addition, a coating layer such as a clear layer may be further laminated on the coating layer using these block polyisocyanate compositions, and the block polyisocyanate composition having good adhesion when laminated, and The one-component coating composition used is desired. On the other hand, depending on the case of using these block polyisocyanate compositions, the compatibility with some polyols may be insufficient.

  Therefore, the present invention provides a block polyisocyanate composition that is excellent in adhesion to an upper layer coating film and excellent in compatibility with a polyol when the coating layer is laminated while maintaining low temperature curability. With the goal.

  As a result of diligent research, the present inventors have surprisingly found that the block polyisocyanate composition containing a specific ratio of a compound having a specific structure has an upper layer when the coating film is laminated while maintaining low-temperature curability. The present inventors have found that it has excellent adhesion to a coating film and excellent compatibility with a polyol, and has completed the present invention.

That is, the present invention has the following configuration.
[1]
A block polyisocyanate obtained from a polyisocyanate derived from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, and a blocking agent,
The blocking agent includes at least one selected from the group consisting of a malonic acid diester compound represented by the following formula (I) and a β ketoester compound represented by the following formula (II):
The molar ratio of the sum of the keto structure shown in the following formula (III) and the sum of the keto structure shown in the following formula (IV) to the sum of the enol structure shown in the following formula (V) and the enol structure shown in the following formula (VI). Is a block polyisocyanate composition having a ratio of 75/25 to 97/3.
(Formula (in I) ~ (VI), R ₁ and R ₂ are each independently an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a phenyl group, a benzyl group. Plurality of R ₁ or R ₂ is independent of each other.)
[2]
The block polyisocyanate composition according to [1], wherein a molar ratio of the total keto structure to the total enol structure is 75/25 or more and 96/4 or less.
[3]
The blocking agent includes the malonic acid diester compound,
The block according to [1] or [2], wherein the ratio of the methanetetracarbonyl structure represented by the following formula (VII) to the total amount of the isocyanate-malonic acid diester bond structure is 0.5 mol% or more and 10 mol% or less. Polyisocyanate composition.
(In the formula (VII), R ₁ and R ₂ each independently represents an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a phenyl group, or a benzyl group.)
[4]
Further comprising a monohydric alcohol compound,
When the number of moles of the following three bonds contained in the block polyisocyanate is (a) to (c), respectively, (a) / ((a) + (b) + (c)) = 0.020 The block polyisocyanate composition according to any one of [1] to [3], which is less than 0.50.
(A) Urethane bond between isocyanate group and monohydric alcohol compound (b) Bond between isocyanate group and malonic acid diester compound (c) Bond between isocyanate group and β-ketoester compound [5]
Further comprising a monohydric alcohol compound,
The blocked polyisocyanate composition has a structure in which an isocyanate group is blocked with an enol body of the malonic acid diester compound, and includes at least a blocked isocyanate structure represented by the formula (V),
In the block polyisocyanate composition, the molar ratio of the block isocyanate structure in which at least one of R ₁ and R ₂ in the formula (V) represents an alkyl group having 4 to 8 carbon atoms with respect to the total amount of the blocked isocyanate structure is The block polyisocyanate composition according to any one of [1] to [4], which is 0.50 or more and less than 0.95.
[6]
The block polyisocyanate composition according to any one of [1] to [5], wherein the blocking agent includes the malonic acid diester compound and the β ketoester compound.
[7]
The block polyisocyanate composition according to [6], wherein a molar ratio of the malonic acid diester compound to the β keto ester compound exceeds 1.0.
[8]
The malonic acid diester compound is diethyl malonate, and
The block polyisocyanate composition according to any one of [1] to [7], wherein the β ketoester compound is ethyl acetoacetate.
[9]
A one-component coating composition comprising the block polyisocyanate composition according to any one of [1] to [8] and a polyol.
[10]
The coating film formed with the one-pack type coating composition as described in [9].
[11]
[9] A coated article coated with the one-component coating composition according to [9].

  According to the block polyisocyanate composition according to the present invention, the adhesiveness with the upper coating film is excellent when the coating film is laminated while maintaining the low temperature curability, and the compatibility with the polyol is also excellent.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.

[Block polyisocyanate composition]
The block polyisocyanate composition of this embodiment includes a block polyisocyanate obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a blocking agent. . The blocking agent contains at least one selected from the group consisting of a malonic acid diester compound represented by the following formula (I) and a β ketoester compound represented by the following formula (II). Further, the block polyisocyanate composition comprises an enol structure represented by the following formula (V) and a keto structure represented by the following formula (III) and a formula (IV) represented by the following formula (VI). The molar ratio of the keto structure shown in is 75/25 or more and 97/3 or less.
(In the above formula (I) ~ (VI), R ₁ and R ₂ are each independently an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a phenyl group, a benzyl group. Plurality of R ₁ or R ₂ is independent of each other.)

The block polyisocyanate composition of the present embodiment includes at least one of a keto body structure represented by the above formula (III) and a keto body structure represented by the above formula (IV), an enol body structure represented by the above formula (V), and the above At least one enol structure represented by the formula (VI) is contained as an essential component. In the above formulas (III) to (VI), R ₁ and R ₂ each independently represent an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a phenyl group, or a benzyl group. R ₁ and R ₂ may be the same or different. In addition, when it represents an alkyl group or cycloalkyl group having 8 or less carbon atoms, the effective NCO content may be suppressed from decreasing, and the compatibility with the main agent when used as a paint may be suppressed from decreasing. preferable. Among these, R ₁ and R ₂ preferably each independently represent an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and more preferably Represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, or an n-butyl group, more preferably a methyl group or an ethyl group, and even more preferably an ethyl group. It is.

  The molar ratio of the keto structure shown in the formula (III) and the keto structure shown in the formula (IV) to the sum of the enol structure shown in the formula (V) and the enol structure shown in the formula (VI) is as follows: 75/25 or more and 97/3 or less. The molar ratio is preferably 75/25 or more and 96/4 or less, more preferably the molar ratio is 80/20 or more and 95/5 or less, and further preferably the molar ratio is 85/15 or more and 94/6 or less. More preferably, the molar ratio is 87/13 or more and 93/7 or less. When the molar ratio is 75/25 or more, good compatibility with the polyol can be obtained. Moreover, by the said molar ratio being 97/3 or less, the adhesiveness with the upper layer coating film further coated on the coating layer using the block polyisocyanate composition of this embodiment can be expressed. The molar ratio can be measured by the method described in Examples described later.

In the block polyisocyanate composition of the present embodiment, the blocking agent contains a malonic acid diester compound, and the block polyisocyanate composition has the following formula (VII) with respect to the total amount (100 mol%) of the isocyanate-malonic acid diester bond structure. It is preferable that the ratio of the methanetetracarbonyl structure represented by these is 0.5 mol% or more and 10 mol% or less.

The block polyisocyanate composition of the present embodiment preferably has a methane tetracarbonyl structure represented by the above formula (VII). R ₁ and R ₂ in the above formula (VII) each independently represent an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a benzyl group. R ₁ and R ₂ may be the same or different. R ₁ and R ₂ are each independently a methanetetracarbonyl structure having an alkyl group having 8 or less carbon atoms, a phenyl group, and a benzyl group, so that a decrease in the effective NCO content is suppressed and a paint is obtained. It tends to be able to improve the compatibility with the main agent and so on, and is more preferable. Among these, R ₁ and R ₂ are each preferably a tetra carbonyl structure an alkyl group having 1 to 8 carbon atoms independently, and more preferably tetra carbonyl represents an alkyl group having 1 to 4 carbon atoms And a methanetetracarbonyl structure showing an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group.

  In the block polyisocyanate composition, the ratio of the methane tetracarbonyl structure represented by the above formula (VII) to the total amount (100 mol%) of the isocyanate-malonic acid diester bond structure is preferably 0.5 mol% or more and 10 mol% or less. It is. The lower limit of the ratio is more preferably 0.7 mol%, still more preferably 1.0 mol%, still more preferably 1.5 mol%, and even more preferably 2.0 mol%. %. The upper limit of the ratio is more preferably 8.0 mol%, still more preferably 6.0 mol%, still more preferably 5.0 mol%, and even more preferably 4.0 mol%. %. When the ratio is 0.5 mol% or more, the coating layer using the block polyisocyanate composition of the present embodiment can further exhibit adhesion to the coated upper layer coating film, and When the ratio is 10 mol% or less, the compatibility with the polyol tends to be maintained. The said ratio can be measured by the method as described in the Example mentioned later.

  The isocyanate-malonic acid diester bond structure indicates a structure in which an isocyanate group and a malonic acid diester are chemically bonded, and examples thereof include a methanetricarbonyl structure (keto form, enol form) and a methanetetracarbonyl structure.

  In this embodiment, by containing a specific range amount of the methanetetracarbonyl structure represented by the above formula (VII), not only low-temperature curability but also adhesiveness with the upper coating film is developed, and a phase with a polyol is obtained. It was surprising that a blocked polyisocyanate composition with excellent solubility was obtained.

  It is preferable that the block polyisocyanate composition of this embodiment further contains the monohydric alcohol compound mentioned later. In the block polyisocyanate composition, the molar ratio of the monohydric alcohol compound to the block polyisocyanate group in the block polyisocyanate composition is more preferably from 0.2 to 10.

  Although it does not specifically limit as said monohydric alcohol compound, For example, monohydric alcohol compounds, such as aliphatic, alicyclic, and aromatic, are mentioned, Among these, it is preferable that it is an aliphatic monohydric alcohol compound. Although an aliphatic monohydric alcohol compound is not specifically limited, It is more preferable that it is a C1-C20 monohydric alcohol compound. Although it does not specifically limit as a C1-C20 monohydric alcohol compound, For example, methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, t-butanol, 2-ethyl-1-propanol, n-amyl alcohol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2,2 -Saturated alcohols such as dimethyl-1-propanol; ether alcohols such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, and 3,6-dioxa-1-heptanol.

  The molar ratio of the monohydric alcohol compound to the blocked isocyanate group contained in the block polyisocyanate composition is more preferably 0.2 or more and 10 or less. The lower limit of the molar ratio is more preferably 0.4, even more preferably 0.7, and still more preferably 1.0. Further, the upper limit value of the molar ratio is more preferably 7.0, still more preferably 5.0, and still more preferably 3.0. When the molar ratio is 0.2 or more, the storage stability when a one-component coating composition is obtained tends to be ensured, and when the molar ratio is 10 or less, the effective NCO content is It tends to be possible to suppress the decrease of

  The effective isocyanate group content of the block polyisocyanate (hereinafter referred to as effective NCO group content) is the content of isocyanate groups that are potentially present relative to the total mass of the block polyisocyanate.

  The effective NCO content of the block polyisocyanate composition (hereinafter referred to as “effective NCO group content”) is not particularly limited, but is 3.0% by mass or more and 22% by mass with respect to the total solid content (100% by mass). It is preferably no greater than mass%, more preferably no less than 5.0 mass% and no greater than 20 mass%, even more preferably no less than 8.0 mass% and no greater than 20 mass%, and no less than 8.0 mass% and no greater than 18 mass%. More preferably, it is 10 mass% or less, and further more preferably 10 mass% or more and 15 mass% or less. When the effective NCO group content is 3.0% by mass or more and 22% by mass or less with respect to the total solid content (100% by mass), low temperature stability and storage stability tend to be compatible. Moreover, when the effective NCO content is 8.0% by mass or more with respect to the total amount of solids (100% by mass), the crosslinking density after baking tends to be favorably maintained, and the effective NCO content is 20%. It exists in the tendency which ensures the smoothness of the coating film after baking by being below mass%. For example, in order to obtain a block polyisocyanate composition having an effective NCO content of 8.0% by mass or more and 20% by mass or less with respect to the total solid content (100% by mass), for example, the NCO content is 15% by mass. % To 25% by mass of polyisocyanate may be used as a raw material. Effective NCO content rate can be measured by the method as described in the Example mentioned later.

  The effective NCO group content is also determined from the amount of polyisocyanate charged, the NCO group content, and the amount of blocking agent charged.

  The solid content concentration of the block polyisocyanate composition is not particularly limited, but is preferably 40% by mass or more and 80% by mass or less, and more preferably 50% by mass or more and 70% by mass or less. When the solid content concentration is 40% by mass or more, the amount of volatilization during baking tends to be reduced, and when the solid content concentration is 80% by mass or less, workability when blending the block polyisocyanate composition is good. Tend to be. In order to obtain a polyisocyanate having a solid content concentration of 40% by mass or more and 80% by mass or less, a solvent may be added before and after the synthesis of the block polyisocyanate composition so as to obtain the solid content concentration. The solid content concentration can be measured by the method described in Examples described later.

  The block polyisocyanate composition in the present embodiment further contains a monohydric alcohol compound, and (a) a urethane bond between the isocyanate group and the monohydric alcohol compound contained in the block polyisocyanate, (b) an isocyanate group and malon. When the number of moles of the bond with the acid diester compound and (c) the bond between the isocyanate group and the β-ketoester compound are (a) to (c), respectively, (a) / ((a) + ( b) + (c)) is more preferably 0.0020 or more and less than 0.50.

  The block polyisocyanate composition of the present embodiment tends to be able to provide a block polyisocyanate composition that is more compatible with compatibility with the main agent and storage stability at low temperatures by taking the above-described form.

The block polyisocyanate composition of this embodiment further contains a monohydric alcohol compound, and the block polyisocyanate composition has a structure in which an isocyanate group is blocked with an enol body of the malonic acid diester compound, and the following formula ( V) includes at least a blocked isocyanate structure represented by formula (V), and in the block polyisocyanate composition, at least one of R ₁ and R ₂ in the formula (V) with respect to the total amount of the blocked isocyanate structure has 4 to 8 carbon atoms. The molar ratio of the blocked isocyanate structure showing an alkyl group is more preferably 0.50 or more and less than 0.95.
In formula (V), R ₁ and R ₂ represents an alkyl group having 1 to 8 carbon atoms each independently.

  The block polyisocyanate composition of this embodiment tends to be more excellent in low-temperature curability, compatibility, and storage stability by taking the above form.

  The block polyisocyanate composition of the present embodiment has a structure in which an isocyanate group contained in a polyisocyanate described later is blocked with an enol body of malonic acid diester, and includes at least a blocked isocyanate structure represented by the formula (V). It is more preferable. In order to obtain a blocked polyisocyanate composition containing such a blocked isocyanate structure, for example, after blocking a polyisocyanate described later with a malonic acid diester, it may be further reacted with a monohydric alcohol compound. In such a blocked polyisocyanate, a part of the isocyanate group of the polyisocyanate is blocked with a blocking agent containing the malonic acid diester. That is, the blocked isocyanate structure may include a structure that is still blocked with a malonic acid diester described later and a structure after reacting with a monohydric alcohol compound.

Further, the block polyisocyanate composition preferably includes a block isocyanate structure in which at least one of R ₁ and R ₂ in the formula (V) represents an ethyl group, from the viewpoint of low temperature curability. In order to obtain a block polyisocyanate composition containing a block isocyanate structure in which at least one of R ₁ and R ₂ in formula (V) represents an ethyl group, for example, diethyl malonate may be used as a malonic acid diester described later.

In the block polyisocyanate composition, the molar ratio of the block isocyanate structure in which at least one of R ₁ and R ₂ in Formula (V) represents an alkyl group having 4 to 8 carbon atoms is based on the total amount of the block isocyanate structure, Preferably they are 0.50 or more and less than 0.95, More preferably, they are 0.60 or more and 0.93 or less, More preferably, they are 0.65 or more and 0.91 or less, More preferably, they are 0.70 or more and 0 or less. .90 or less. When the molar ratio is in such a range, curability and compatibility tend to be improved. The molar ratio can be measured by the method described in Examples described later.

<Polyisocyanate>
The polyisocyanate of this embodiment is derived from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

  The polyisocyanate of this embodiment is a multimer consisting of one or more diisocyanates selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and consisting of dimers or more of the diisocyanates.

  In the present embodiment, the “aliphatic diisocyanate” refers to a compound having two isocyanate groups and a chain aliphatic hydrocarbon in the molecule and having no aromatic hydrocarbon. In the present embodiment, “aliphatic diisocyanate” refers to a compound having a chain aliphatic hydrocarbon and not having an aromatic hydrocarbon, excluding an isocyanate group in the molecule.

  The aliphatic diisocyanate is not particularly limited, but is preferably an aliphatic diisocyanate having 4.0 to 30 carbon atoms. For example, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (hereinafter abbreviated as “HDI”), butane diisocyanate. , Pentane diisocyanate, trimethylhexamethylene diisocyanate, 2,2,4-trimethyl-1,6-diisocyanatohexane, lysine diisocyanate. Use of such an aliphatic diisocyanate is more preferable because the resulting polyisocyanate has a low viscosity. Among these, HDI is more preferable from the viewpoint of industrial availability. Aliphatic diisocyanates may be used alone or in combination of two or more.

  In the present embodiment, “alicyclic diisocyanate” refers to a compound having two isocyanate groups and a cyclic aliphatic hydrocarbon having no aromaticity in the molecule. In the present embodiment, the “alicyclic diisocyanate” also refers to a compound having a cyclic aliphatic hydrocarbon having no aromaticity in the molecule.

  Although it does not specifically limit as alicyclic diisocyanate, A C8-C30 thing is preferable, for example, isophorone diisocyanate (henceforth "IPDI"), 1, 3-bis (isocyanatomethyl) -Cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, norbornene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,4-cyclohexane diisocyanate. Among these, IPDI is more preferable because of weather resistance and industrial availability. An alicyclic diisocyanate may be used independently and may use 2 or more types together.

  Among the aliphatic and alicyclic diisocyanates, HDI, isophorone diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate are preferable because they are easily available industrially, and HDI is more preferable. By using HDI, the weather resistance and flexibility of the coating film obtained from the polyisocyanate composition tend to be more excellent.

  Aliphatic and alicyclic diisocyanates may be used alone or in combination of two or more.

  The polyisocyanate derived from the above-mentioned diisocyanate is not particularly limited. For example, biuret bond, urea bond, isocyanurate bond, uretdione bond, urethane bond, allophanate may be added to the aliphatic diisocyanate and / or the alicyclic diisocyanate. Examples thereof include diisocyanate di- to 20-mer oligomers produced by forming bonds, oxadiazinetrione bonds, and the like. The polyisocyanate having a biuret bond is, for example, a so-called biuretizing agent such as water, t-butanol or urea and a diisocyanate at a molar ratio of the biuretizing agent to the isocyanate group of the diisocyanate of about 1/2 to about 1/100. After the reaction, it is obtained by removing and purifying unreacted diisocyanate. A polyisocyanate having an isocyanurate bond is obtained by, for example, carrying out a cyclic trimerization reaction with a catalyst or the like, stopping the reaction when the conversion rate is about 5 to about 80% by mass, and removing and purifying unreacted diisocyanate. . In this case, a 1-6 valent alcohol compound such as 1,3-butanediol or trimethylolpropane can be used in combination.

  As the catalyst for producing the polyisocyanate having an isocyanurate bond, a catalyst having basicity is generally preferable. Examples of such catalysts include (1) tetraalkylammonium hydroxides such as tetramethylammonium, tetraethylammonium, tetrabutylammonium, and trimethylbenzylammonium, organic weak acid salts such as acetic acid and capric acid, (2 ) Hydroxyalkylammonium hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, triethylhydroxyethylammonium, etc., organic weak acid salts such as acetic acid and capric acid, and (3) alkylcarboxylic acid such as tin Alkyl metal salts such as zinc and lead, (4) metal alcoholates such as sodium and potassium, and (5) aminosilyl group-containing compounds such as hexamethyldisilazane , (6) Mannich bases, (7) in combination with tertiary amines with epoxy compounds, (8) phosphorus compounds such as tributylphosphine and the like, may be used in combination of two or more of these.

  When the catalyst may adversely affect the properties of the paint or coating film, it is preferable to neutralize the catalyst with an acidic compound or the like. The acidic compound in this case is not particularly limited. For example, inorganic acids such as hydrochloric acid, phosphorous acid, phosphoric acid; methanesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid methyl ester, p-toluenesulfonic acid ethyl Sulfonic acids such as esters or derivatives thereof; ethyl phosphate, diethyl phosphate, isopropyl phosphate, diisopropyl phosphate, butyl phosphate, dibutyl phosphate, 2-ethylhexyl phosphate, di (2-ethylhexyl) phosphate, isodecyl phosphate, diisodecyl phosphate, oleyl acid phosphate, Examples include tetracosyl acid phosphate, ethyl glycol acid phosphate, butyl pyrophosphate, and butyl phosphite, and two or more of these may be used in combination.

  The polyisocyanate having a urethane bond is, for example, a di-isocyanate and a bivalent to hexavalent alcohol compound such as trimethylolpropane, and the molar ratio of the hydroxyl group of the alcohol compound to the isocyanate group of the diisocyanate is about 1/2 to about 1 /. After reacting at 100, unreacted diisocyanate can be removed and purified.

  The NCO content of the polyisocyanate (hereinafter also referred to as “isocyanate content”) is not particularly limited, but may be 10% by mass or more and 25% by mass or less with respect to the total solid content (100% by mass). More preferably, it is 13 mass% or more and 24 mass% or less, More preferably, it is 15 mass% or more and 25 mass% or less, More preferably, it is 17 mass% or more and 24 mass% or less, More preferably, it is 17 The mass is not less than 22% by mass. When the isocyanate content is 15% by mass or more, the crosslinking density of the coating film after baking is ensured, and good curability tends to be obtained. When the isocyanate content is 25% by mass or less, coating after baking is performed. It tends to ensure the flexibility of the film. In order to obtain a polyisocyanate having an NCO content of 15% by mass or more and 25% by mass or less with respect to the total amount (100% by mass) of the solid content, an appropriate 2- to 6-valent alcohol compound is appropriately converted. The method to use etc. are mentioned. The NCO content can be measured by the method described in Examples described later.

  The NCO group content of the polyisocyanate can also be obtained, for example, by reacting the isocyanate group of the polyisocyanate with an excess of amine (such as dibutylamine) and back titrating the remaining amine with an acid such as hydrochloric acid.

  The viscosity of the polyisocyanate is not particularly limited, but is preferably 50 mPa · s or more and 2,000,000 mPa · s or less at 25 ° C., more preferably 100 mPa · s or more and 100,000 mPa · s or less, and further preferably It is 300 mPa · s or more and 50,000 mPa · s or less, and more preferably 3,000 mPa · s or more and 50,000 mPa · s or less. When the viscosity is 50 mPa · s or more, there is a tendency that the crosslinkability during baking can be secured well, and when the viscosity is 2,000,000 mPa · s or less, the coating film smoothness after baking is good. Tends to be maintained. Moreover, it exists in the tendency for sufficient sclerosis | hardenability and favorable coating-film external appearance to be obtained because a viscosity exists in such a range. In order to obtain a polyisocyanate having a viscosity of 100 mPa · s or more and 100,000 mPa · s or less, a method of appropriately using a divalent to hexavalent alcohol compound at an appropriate conversion rate may be used. A viscosity can be measured by the method as described in the Example mentioned later.

  The number average molecular weight of the polyisocyanate is not particularly limited, but is preferably 500 or more and 1500 or less, and more preferably 600 or more and 1300 or less. When the number average molecular weight is 500 or more, the flexibility of the coating film after baking tends to be secured favorably, and when the number average molecular weight is 1500 or less, the crosslinking density of the coating film after baking tends to be secured favorably. is there. In order to obtain a polyisocyanate having a number average molecular weight of 500 or more and 1500 or less, for example, the addition rate of the isocyanuration reaction may be set to 5.0 mass% to 80 mass%. The number average molecular weight can be measured by the method described in Examples described later.

  The residual HDI concentration of the polyisocyanate is not particularly limited, but is preferably 2.0% by mass or less, more preferably 1.0% by mass or less, still more preferably 0.7% by mass or less, and even more. Preferably it is 0.5 mass% or less. When the residual HDI concentration is 2.0% by mass or less, there is a tendency that the danger during handling can be further reduced and the curability when the coating composition is obtained can be further improved. In order to obtain a polyisocyanate having a residual HDI concentration of 2.0% by mass or less, the polyisocyanate may be removed by evaporating a thin film, extracting, or the like after the production of the polyisocyanate. The residual HDI concentration can be measured by the method described in Examples described later.

  The average number of isocyanate groups of the polyisocyanate formed from one or more selected from these polyisocyanates is preferably 2.0 or more and 20 or less. The lower limit of the average number of isocyanate groups is more preferably 2.3, still more preferably 2.5, and even more preferably 3.0. The upper limit of the average number of isocyanate groups is more preferably 15 and even more preferably 10. When the average number of isocyanate groups is 2.0 or more, the crosslinkability is improved, and when a blocked polyisocyanate is obtained, low temperature curability tends to be exhibited. On the other hand, when the average number of isocyanate groups is 20 or less, the viscosity is prevented from becoming too high, and a polyisocyanate having good workability tends to be obtained.

The average number of isocyanate groups is determined by the following formula. The number average molecular weight and isocyanate group mass% in the following formula are the above-described number average molecular weight and isocyanate content (mass%).

  The polyisocyanate is not particularly limited, and for example, biuret group (bond), urea group (bond), isocyanurate group (bond), uretdione group (bond), urethane group (bond), allophanate group (bond), oxadia Examples thereof include polyisocyanates having one or two or more groups (bonds) selected from the group consisting of a gintrione group and an iminooxadiazinedione group.

  The polyisocyanate having a biuret bond is not particularly limited. For example, a so-called biuret agent such as water, t-butanol or urea and a diisocyanate have a molar ratio of (biuret agent) / (isocyanate group of diisocyanate) of about After reacting under the condition of 1/2 to about 1/100, it can be obtained by removing unreacted diisocyanate. These techniques are disclosed in, for example, JP-A-53-106797, JP-A-55-11452, and JP-A-59-95259.

  The polyisocyanate having a urea bond is not particularly limited, and can be formed, for example, from a compound having an isocyanate group and a compound having water or an amine group. The content of urea bonds in the polyisocyanate is preferably small. Thereby, it exists in the tendency for the polyisocyanate obtained to become difficult to aggregate.

  The polyisocyanate having an isocyanurate bond is not particularly limited. For example, the isocyanurate conversion reaction of diisocyanate is performed with a catalyst or the like, and the reaction is stopped when the conversion rate is about 5 to about 80% by mass, and the unreacted It can be obtained by removing the diisocyanate. The isocyanuration reaction catalyst used in this case is not particularly limited, but specifically, those having basicity are generally preferred, and tetraalkylammonium hydroxide or acetic acid such as tetramethylammonium and tetraethylammonium. , Organic weak acid salts such as capric acid; hydroxyalkylammonium hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, triethylhydroxyethylammonium, etc .; or organic weak acid salts such as acetic acid and capric acid; acetic acid Alkali metal salts of alkyl carboxylic acids such as caproic acid, octylic acid and myristic acid, such as tin, zinc and lead; metal alcoholates such as sodium and potassium; Aminosilyl group-containing compounds such as hexamethyldisilazane; is for example, phosphorus compounds such as tributylphosphine and the like; Mannich bases; combination with tertiary amines and epoxy compounds. It is preferable that the usage-amount of these catalysts is selected from the range of 10 ppm-1% with respect to the mass of the diisocyanate which is a raw material, and the alcohol polyol added as needed. When the isocyanuration reaction is completed, for example, there are a method of neutralizing the isocyanuration reaction catalyst and a method of inactivation by adding an acidic substance such as phosphoric acid or acidic phosphate, thermal decomposition, or chemical decomposition. Can be mentioned.

  The polyisocyanate having a uretdione bond is not particularly limited, but can be obtained by using, for example, a diisocyanate and a uretdione-forming reaction catalyst. Although it does not specifically limit as a uretdione-ized reaction catalyst, Specifically, Tris (dialkylamino), such as trialkyl phosphine, such as tri-n-butylphosphine and tri-n-octylphosphine, tris- (dimethylamino) -phosphine. ) Third phosphines such as phosphine and cycloalkylphosphine such as cyclohexyl-di-n-hexylphosphine. These compounds can also serve as allophanatization reaction catalysts. In addition, many of these compounds simultaneously promote the isocyanuration reaction to produce isocyanurate group-containing polyisocyanates such as isocyanurate trimers in addition to uretdione group-containing polyisocyanates such as uretdione dimers. Can do. Moreover, the uretdione dimer can also be obtained by heating without using a uretdione-forming reaction catalyst. The uretdione group-containing polyisocyanate such as the uretdione dimer of the present embodiment is more preferably produced by heating from the viewpoint of storage stability.

  The polyisocyanate having a urethane bond is not particularly limited. For example, a compound having a hydroxyl group and diisocyanate are reacted at an equivalent ratio of hydroxyl group to isocyanate group (hydroxyl group / isocyanate group) of about 1/2 to about 1/100. Then, it can be obtained by removing the unreacted diisocyanate monomer. The reaction temperature is preferably 20 to 200 ° C., more preferably 40 to 150 ° C., and further preferably 60 to 120 ° C. from the viewpoint of reaction rate, suppression of side reactions, and prevention of coloring. Moreover, reaction time is the same point as reaction temperature, Preferably it is 10 minutes-24 hours, More preferably, it is 15 minutes-15 hours, More preferably, it is 20 minutes-10 hours. The urethanization reaction can be performed without a catalyst or in the presence of a catalyst such as a tin-based catalyst or an amine-based catalyst.

  The polyisocyanate having an allophanate group is formed from a compound having a hydroxyl group of an alcohol and an isocyanate group. In order to generate an allophanate group, it is preferable to use an allophanate reaction catalyst. Although it does not specifically limit as an allophanatization reaction catalyst, For example, alkyl carboxylate, such as tin, lead, zinc, bismuth, zirconium, zirconyl, is mentioned, Specifically, 2-ethyl hexanoic acid tin, dibutyl tin dilaurate Organic tin compounds such as lead 2-ethylhexanoate; Organic zinc compounds such as zinc 2-ethylhexanoate; Organic bismuth compounds such as bismuth 2-ethylhexanoate; Zirconium 2-ethylhexanoate Organic zirconium compounds; organic zirconyl compounds such as zirconyl 2-ethylhexanoate can be mentioned, and two or more of these can be used in combination. Moreover, said isocyanurate formation reaction catalyst can also be used as an allophanatization reaction catalyst. When an allophanate reaction is carried out using an isocyanurate reaction catalyst, an isocyanurate group-containing polyisocyanate can also be produced. It is economical and more preferable in production to use an isocyanurate reaction catalyst as the allophanate reaction catalyst and to perform the allophanate reaction and the isocyanurate reaction simultaneously.

The molar ratio of allophanate group / isocyanurate group derived from the alcohol is preferably 1.0% or more and 50% or less, more preferably 1.0% or more and 40% or less, from the viewpoint of viscosity and curability. More preferably, it is 1.0% or more and 30% or less. The molar ratio of allophanate group / isocyanurate group can be measured by ¹ HNMR.

  The amount of the alcohol added is preferably 1/1000 or more and 1/10 or less, more preferably 1/1000 or more and 1/100 or less, in terms of the equivalent ratio of the hydroxyl group of the alcohol to the isocyanate group of the diisocyanate. By setting it to 1/1000 or more, the average number of allophanate groups tends to increase, and the resulting block polyisocyanate composition tends to have a lower viscosity, which is preferable. Moreover, it is preferable for it to be 1/10 or less because the average number of isocyanate groups tends to increase and the curability is excellent.

  The polyisocyanate having an iminooxadiazinedione bond is not particularly limited, and can be obtained using, for example, a diisocyanate and a specific catalyst. A technique related to this is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-534870.

  Among the above-mentioned bonds, a polyisocyanate containing a biuret group, an isocyanurate group, a urethane group, or an allophanate group is preferable from the viewpoint of weather resistance, heat resistance, curability, and compatibility.

<Blocking agent>
In the block polyisocyanate composition of the present embodiment, the blocking agent includes a malonic acid diester compound represented by the following formula (I) (hereinafter also simply referred to as “malonic acid diester compound”) and β represented by the following formula (II). It contains at least one selected from the group consisting of keto ester compounds (hereinafter also simply referred to as “β keto ester compounds”), and more preferably contains both malonic acid diester compounds and β keto ester compounds.
In the above formula (I) and formula (II), R ₁ and R ₂ each independently represent an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a phenyl group, or a benzyl group. R ₁ and R ₂ may be the same or different, but are preferably the same from the standpoint of availability. When R ₁ and R ₂ represent an alkyl group or cycloalkyl group having 8 or less carbon atoms, the decrease in the effective NCO content is suppressed, and the deterioration in compatibility with the main agent and the like when used as a paint is suppressed. Tend to be able to. Among these, it is preferable to indicate an alkyl group having 1 to 8 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, or an n- group of an alkyl group having 1 to 4 carbon atoms. It represents a butyl group, more preferably a methyl group or an ethyl group, and even more preferably an ethyl group. Here, the effective NCO content is an isocyanate content (mass%) potentially present with respect to the total amount (100 mass%) of the block polyisocyanate composition.

  In the block polyisocyanate composition of this embodiment, a part of the isocyanate group contained in the polyisocyanate (located at the terminal) is blocked (blocked) with a blocking agent.

As the blocking agent, at least one active methylene compound selected from the group consisting of a malonic acid diester compound and a β ketoester compound is used. Moreover, when an isocyanate group is blocked with these active methylene compounds, the blocked isocyanate group has an amide structure as represented by the following general formula (1).
(In Formula (1), R represents a polyisocyanate residue, R ₁ and R ₂ represent at least one selected from an alkyl group or an alkyloxy group. R ₁ and R ₂ may be the same or different. Good)

  Specific examples of the malonic acid diester compound are not particularly limited, and examples thereof include, for example, dimethyl malonate, diethyl malonate, di-n-propyl malonate, diisopropyl malonate, di-n-butyl malonate, diisobutyl malonate, and diester malonate. Examples include t-butyl, methyl t-butyl malonate, di-n-hexyl malonate, di-2-ethylhexyl malonate, diphenyl malonate, and dibenzyl malonate. Among them, dimethyl malonate, diethyl malonate, di-n-propyl malonate, diisopropyl malonate, di-n-butyl malonate, diisobutyl malonate, di-t-butyl malonate, methyl t-butyl malonate, malonic acid Di n-hexyl and di-2-ethylhexyl malonate are preferred. More preferred are dimethyl malonate, diethyl malonate, di-n-propyl malonate, diisopropyl malonate, and di-n-butyl malonate, more preferred are dimethyl malonate and diethyl malonate, and even more preferred Diethyl malonate. The malonic acid diester shown above can be used alone or in combination of two or more.

  From the viewpoint of low-temperature curability, preferably 50 equivalent% or more, more preferably 60 equivalent% or more, and still more preferably 80 equivalent% or more of the isocyanate group contained in the polyisocyanate is blocked with a malonic acid diester.

  Specific examples of the β-ketoester compound are not particularly limited, and examples thereof include methyl acetoacetate, ethyl acetoacetate, methyl isobutanoyl acetate, ethyl isobutanoyl acetate, and acetylacetone. Among these, methyl acetoacetate, ethyl acetoacetate, methyl isobutanoyl acetate, and ethyl isobutanoyl acetate are preferable. More preferred are methyl acetoacetate and ethyl acetoacetate, and even more preferred is ethyl acetoacetate. The β ketoester compounds shown above can be used alone or in combination of two or more.

  In addition, examples of the β ketoester compound include isopropyl acetoacetate, n-propyl acetoacetate, t-butyl acetoacetate, n-butyl acetoacetate, and phenyl acetoacetate.

  In view of low-temperature curability and suppression of yellowing, the isocyanate group blocked with β-ketoester is preferably 50 equivalent% or less, more preferably 40 equivalent% or less, more preferably less than the isocyanate group contained in the polyisocyanate. Is 30 equivalent% or less.

  The β-ketoester compound is preferably used in an amount of 50 equivalent% or less based on the isocyanate group of the polyisocyanate from the viewpoint of low-temperature curability and suppression of yellowing. More preferably, it is 40 equivalent% or less, More preferably, it is 30 equivalent% or less, More preferably, it is 20 equivalent% or less.

  The malonic acid diester compound described above is diethyl malonate, and the β ketoester compound described above is preferably an acetoacetic acid ester compound from the viewpoint of more reliably achieving the intended functions and effects of the present invention. More preferably, it is ethyl acetoacetate.

  In the blocking agent of the present embodiment, the molar ratio of the malonic acid diester compound to the β ketoester compound is not particularly limited, but is preferably more than 1.0. The molar ratio is more preferably 1.5 or more, still more preferably 2.0 or more, and even more preferably 3.0 or more. The molar ratio is preferably 50 or less, more preferably 33 or less, still more preferably 20 or less, and even more preferably 10 or less. When the molar ratio exceeds 1.0, the low-temperature curability tends to be improved. On the other hand, when the molar ratio is 50 or less, the crystallinity at a low temperature tends to be suppressed.

  In addition, the β keto ester compound tends to have a higher enol structure ratio than the malonic acid diester compound. Therefore, when the malonic acid diester compound and the β keto ester compound are used in combination, the ratio of both blocking agents is adjusted. It is possible to adjust the molar ratio between the keto structure and the enol structure.

  The blocking agent of this embodiment may further contain a blocking agent other than the malonic acid diester compound and the β keto ester compound (hereinafter also referred to as “other blocking agent”). Although the specific example of another blocking agent is not specifically limited, For example, it is preferable that it is a compound which has one active hydrogen in a molecule | numerator. Although it does not specifically limit as a compound which has one active hydrogen in a molecule | numerator, For example, active methylene type | system | groups other than a malonic acid diester compound and a beta ketoester compound, a mercaptan type, an acid amide type, an acid imide type, an imidazole type, a urea type , Oxime, amine, imide, and pyrazole compounds.

  Other blocking agents include alcohol-based, alkylphenol-based, and phenol-based compounds.

  More specific other blocking agents include: (1) active methylene type other than malonic acid diester compound and β keto ester compound; β keto ester compound such as methyl isobutanoyl acetate and ethyl isobutanoyl acetate, acetylacetone, etc. (2) mercaptan type; butyl Mercaptan, dodecyl mercaptan, etc. (3) acid amide series; acetanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam etc., (4) acid imide series; succinimide, maleic imide, etc. (5 ) Imidazole series; Imidazole, 2-methylimidazole, etc. (6) Urea series; Urea, thiourea, ethylene urea, etc. (7) Oxime series; Formald oxime, Acetoaldoxime, Acetoxime, Methyl ethyl ketoxime (hereinafter MEKO) Abbreviated ), Cyclohexanone oxime, etc. (8) amine system; diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine, diisobutylamine, di (2-butylamine), di (t-butyl) amine, dicyclohexyl Amines, Nt-butylcyclohexylamine, 2-methylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, etc. (9) imine series; ethyleneimine, polyethyleneimine, etc. (10 ) Pyrazole type; pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole and the like can be mentioned.

  Other preferable blocking agents among these are not particularly limited, but are at least selected from active methylene-based and pyrazole-based blocking agents other than oxime-based, amine-based, acid amide-based, malonic acid diester compounds and β-ketoester compounds. 1 type, more preferably at least one selected from active methylene type and pyrazole type blocking agents other than oxime type, malonic acid diester compound and β ketoester compound, and more preferably malonic acid diester compound and β It is at least one selected from active methylene-based blocking agents other than ketoester compounds.

<Monohydric alcohol compound>
In the present embodiment, the monohydric alcohol compound contained in the block polyisocyanate composition is not limited. The monohydric alcohol compound can react with an unreacted (unblocked) isocyanate group of the blocked polyisocyanate, or can undergo an ester exchange reaction with an ester group at the terminal of the blocked polyisocyanate.

  In the block polyisocyanate composition of this embodiment, it exists in the tendency which can suppress significantly crystallization of a block polyisocyanate composition by including this monohydric alcohol compound.

  The number of carbon atoms of the monohydric alcohol compound depends on the storage stability and compatibility when the block polyisocyanate composition is mixed with a polyvalent active hydrogen compound to form a thermosetting composition, and the crystallinity of the block polyisocyanate composition. From the point of suppression, 3 or more and 10 or less are preferable, 4 or more and 9 or less are more preferable, and 4 or more and 8 or less are more preferable. Moreover, the boiling point is preferably 200 ° C. or less, more preferably 80 to 180 ° C., and still more preferably 90 to 160 ° C. from the viewpoint of easy scattering of the solvent and low temperature curability.

  Examples of the monohydric alcohol compound having such a carbon number and boiling point include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, 2-butanol, t-butanol, and n-pentanol. , Iso-pentanol, 2-methyl-1-butanol, n-hexanol, 2-methyl-1-pentanol, 2-ethyl-1-butanol, n-heptanol, n-octanol, 2-ethyl-1-hexanol , Methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, propylene glycol monomethyl ether, cyclohexanol, phenol, benzyl alcohol and the like, and one or two or more can be selected and used.

  In addition, the carbon number of the monohydric alcohol compound is higher than the carbon number of the terminal alkyl group bonded to the malonic acid diester and the β ketoester in terms of compatibility between the block polyisocyanate composition and the polyvalent active hydrogen compound. Is preferred.

  In the present embodiment, the content of the monohydric alcohol compound in the block polyisocyanate composition can be arbitrarily selected, but is preferably 0 to 500 equivalent% (mol%) with respect to the blocked isocyanate group, and more Preferably it is 20-400 equivalent%, More preferably, it is 30-300 equivalent%.

  When the monohydric alcohol compound is contained in the block polyisocyanate composition, the storage stability and compatibility of the thermosetting composition containing the block polyisocyanate composition and the polyvalent active hydrogen compound are improved. Although the detailed factor is not clear, the above monohydric alcohol compound reacts with an unreacted isocyanate group contained in the block polyisocyanate or transesterifies with an ester group contained in the block polyisocyanate. It is considered that the structural symmetry of the block polyisocyanate, the arrangement of the block polyisocyanate molecules, and the like can be destroyed, and this makes the block polyisocyanate composition difficult to crystallize. When the block polyisocyanate composition is crystallized, the interaction with the polyvalent active hydrogen compound cannot be sufficiently obtained and the compatibility is lowered. Therefore, it is considered that the compatibility is improved when the crystallization is suppressed.

  In the block polyisocyanate composition of this embodiment, it is particularly preferable that at least a part of unreacted isocyanate groups contained in the block polyisocyanate form a urethane bond with the monohydric alcohol compound. And the amount of the urethane bond structure formed by the isocyanate group is the number of moles of the urethane bond structure (a), the number of moles of the bond structure between the isocyanate group and the malonic acid diester compound (b), the isocyanate group and β In a molar ratio represented by (a) / ((a) + (b) + (c)) where the number of moles of the bond structure with the ketoester compound is (c), 0.0020 or more and 0 More preferably, it is less than .50.

  According to the study by the present inventors, when the blocked polyisocyanate contains a part of unreacted isocyanate group which is not blocked, and it reacts with a monohydric alcohol compound and has a urethane bond. It has been found that crystallization is very unlikely and is superior in compatibility. However, the ratio is preferably 0.01 or more and 0.40 or less, and more preferably 0.02 or more and 0.30 or less.

  The monohydric alcohol compound of the present embodiment is a compound capable of reacting with an unreacted isocyanate group in the block polyisocyanate of the present embodiment, and / or a terminal alkyl ester residue in the structure of the block polyisocyanate. It is a compound capable of transesterification. Thereby, it exists in the tendency which can suppress crystallization of the block polyisocyanate composition of this embodiment.

  The number of carbon atoms of the monohydric alcohol compound is preferably 3 or more, 10 or less, more preferably 4 or more and 9 or less, and still more preferably 4 or more and 8 or less, from the viewpoints of storage stability, compatibility, and crystallinity suppression. Further, from the viewpoint of easy scattering of the solvent and low temperature curability, the boiling point is preferably 200 ° C. or lower, more preferably 80 ° C. or higher and 180 ° C. or lower, and further preferably 90 ° C. or higher and 160 ° C. or lower.

  Although it does not specifically limit as a monohydric alcohol compound which has the above carbon number and / or boiling point, For example, methanol, ethanol, n-propanol, iso-propanol, n-butanol (1-butanol), iso-butanol (Isobutanol), 2-butanol, t-butanol, n-pentanol, iso-pentanol, 2-methyl-1-butanol, n-hexanol, 2-methyl-1-pentanol, 2-ethyl-1- Butanol, n-heptanol, n-octanol, 2-ethyl-1-hexanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, diethyl carbitol, propylene glycol monomethyl ether, cyclohexanol, phenol, and benzyl alcohol The recited, may be selected and used alone or in combination.

  Although the addition amount of the monohydric alcohol compound is not particularly limited, it is preferably 10 equivalent% or more and 500 equivalent% or less, more preferably 20 equivalent% or more and 400 equivalent% or less, more preferably 30 with respect to the blocked isocyanate group. Equivalent% or more and 300 equivalent% or less.

  By including a monohydric alcohol compound in the block polyisocyanate composition, storage stability and compatibility are improved. Although the detailed factor is not clear, the monohydric alcohol compound reacts with the unreacted isocyanate group or transesterifies with the terminal alkyl ester residue in the structure of the block polyisocyanate, thereby causing the block polyisocyanate to react. It is inferred that the block polyisocyanate composition of the present embodiment is difficult to crystallize because the structural symmetry, the polyisocyanate alignment, etc. can be destroyed (however, the factor is not limited thereto). .

[Method for producing block polyisocyanate composition]
The manufacturing method of the block polyisocyanate composition of this embodiment is demonstrated. The production method of the block polyisocyanate composition of the present embodiment includes a polyisocyanate derived from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, a malonic acid diester compound, and a malonic acid diester compound. A first step of obtaining a block polyisocyanate from a blocking agent other than the following, and a subsequent second step of performing a transesterification reaction of the obtained block polyisocyanate with a monoalcohol (monohydric alcohol compound). Process.

  In the first step of this production method, the malonic acid diester compound, the blocking agent other than the malonic acid diester compound, and the β ketoester compound may be reacted simultaneously with the polyisocyanate. After the reaction with the polyisocyanate, the other blocking agent may be reacted.

  In the present embodiment, the blocking reaction (reaction between polyisocyanate and blocking agent) is preferably performed so as to block all isocyanate groups of the polyisocyanate. From this viewpoint, the molar ratio of the blocking agent to the isocyanate group in the polyisocyanate ((total number of moles of blocking agent) / (number of moles of isocyanate group in the polyisocyanate)) is 1.0 or more and 1.5 or less. preferable. The lower limit of the molar ratio is more preferably 1.015, still more preferably 1.030, and still more preferably 1.045. The upper limit of the molar ratio is more preferably 1.35, further preferably 1.20, and still more preferably 1.10. By setting the lower limit of the molar ratio to 1.0, the low-temperature curability of the block polyisocyanate tends to be expressed more reliably. On the other hand, when the upper limit value of the molar ratio is 1.5 or less, a decrease in drying property after coating tends to be suppressed.

  The reaction in the first step can be performed regardless of the presence or absence of a solvent. When using a solvent, it is preferable to use a solvent which is inert with respect to the isocyanate group. Specific examples of the solvent include, but are not limited to, aromatic hydrocarbons such as toluene and xylene; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ethyl acetate, n-butyl acetate, cellosolve acetate, and the like. Esters: From the group of ethers such as propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether, a solvent can be appropriately selected and used according to the purpose and application. These solvents may be used alone or in combination of two or more.

  In the blocking reaction in the first step, a reaction catalyst (hereinafter also referred to as “blocking reaction catalyst” or simply “catalyst”) can be used. Although it does not specifically limit as a specific reaction catalyst, For example, organometallic salt, such as tin, zinc, lead, metal alcoholate, and tertiary amine are mentioned.

  The blocking reaction catalyst is preferably a basic compound, for example, metal alcoholates such as sodium methylate, sodium ethylate, sodium phenolate and potassium methylate; tetraalkylammonium such as tetramethylammonium, tetraethylammonium and tetrabutylammonium. Hydroxides, organic weak acid salts such as acetates, octylates, myristates and benzoates; alkali metal salts of alkyl carboxylic acids such as acetic acid, caproic acid, octylic acid and myristic acid; acetic acid and caproic acid Metal salts such as tin, zinc and lead of alkyl carboxylic acids such as octylic acid and myristic acid; aminosilyl group-containing compounds such as hexamethylene disilazane; hydroxides of alkali metals such as lithium, sodium and potassium .

  The addition amount of the catalyst is not limited, but is generally 0.01 to 5% by mass, preferably 0.05 to 3% by mass, and particularly preferably 0.1 to 2% by mass with respect to the polyisocyanate. When the addition amount of the catalyst is decreased, the remaining amount of the socyanate group that is not blocked during the blocking reaction tends to increase. The reaction between the polyisocyanate and the active methylene compound can be carried out regardless of the presence or absence of a solvent.

  In the block polyisocyanate composition of the present embodiment, in order to adjust the molar ratio between the keto structure and the enol structure, and to ensure the amount of methane tetracarbonyl structure produced, the reaction catalyst takes time. Therefore, it is preferable to add continuously. The time for dropping is preferably from 2.0 minutes to 120 minutes. The lower limit of the time is more preferably 3.0 minutes, still more preferably 4.0 minutes, and even more preferably 5.0 minutes. The upper limit of the time is more preferably 90 minutes, further preferably 60 minutes, and still more preferably 30 minutes. By setting the lower limit of the time to 2.0 minutes or more, when the malonic acid diester compound is used in a large ratio as a blocking agent, the content ratio of the molar ratio of the enol structure tends to be increased. Moreover, it tends to be easy to adjust to the range of the present embodiment by increasing the amount of methane tetracarbonyl structure generated. On the other hand, by setting the upper limit of the time to 120 minutes or less, the content ratio of the molar ratio of the enol structure can be prevented from becoming too high, and the amount of methanetetracarbonyl structure produced is not increased too much. It can be easily adjusted within the range of the embodiment, and the reaction time extension tends to be suppressed. In addition, when the said reaction catalyst is mixed with a blocking agent and added to polyisocyanate, there exists a tendency for the content rate of a keto body structure to become very high.

  When the reaction catalyst used may adversely affect the properties of the paint or coating film, it is preferable to deactivate the reaction catalyst with an acidic compound or the like. Specific examples of the acidic compound in this case are not particularly limited. For example, inorganic acids such as hydrochloric acid, phosphorous acid, phosphoric acid; methanesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid methyl ester, p-toluene Sulfonic acid or its derivatives such as sulfonic acid ethyl ester; monoethyl phosphate, diethyl phosphate, monoisopropyl phosphate, diisopropyl phosphate, monobutyl phosphate, dibutyl phosphate, mono (2-ethylhexyl) phosphate, di (2-ethylhexyl) phosphate, monoisodecyl phosphate, Examples thereof include diisodecyl phosphate, oleyl acid phosphate, tetracosyl acid phosphate, ethyl glycol acid phosphate, butyl pyrophosphate, and butyl phosphite. These acidic compounds can be used alone or in combination of two or more.

  The reaction temperature in the first step is preferably -20 ° C or higher and 150 ° C or lower, more preferably 0 ° C or higher and 120 ° C or lower, more preferably 40 ° C or higher, from the viewpoint of suppression of side reactions and reaction efficiency. It is 100 degrees C or less. By performing the reaction at a reaction temperature of 150 ° C. or lower, side reactions can be suppressed, and the remaining amount of isocyanate groups that are not blocked during the blocking reaction tends to increase. In addition, by performing the reaction at a reaction temperature of −20 ° C. or higher, the reaction rate tends to be maintained high.

  The reaction time between the polyisocyanate and the blocking agent can be generally 0.1 to 6 hours, but is preferably 0.5 to 4 hours from the viewpoint of optimizing the amount of urethane bond structure produced. . If the reaction time is shortened, the remaining amount of isocyanate groups that are not blocked during the blocking reaction tends to increase.

  Moreover, it is also preferable that reaction temperature and reaction time shall be 50-180 degreeC and 10-480 minutes, for example.

  Next, the second step will be described. The second step is a step of reacting the block polyisocyanate obtained in the first step with a monohydric alcohol compound.

  The block polyisocyanate composition and the monohydric alcohol are used in order to improve the storage stability when blended with at least one selected from the group consisting of polyols, polyamines and alkanolamines. As the step of mixing and reacting the compound, the second step is preferably performed.

  The mixing temperature in the second step is preferably -20 ° C or higher and 150 ° C or lower, more preferably 0 ° C or higher and 120 ° C or lower, and further preferably 40 ° C or higher and 100 ° C or lower. By performing the reaction at a mixing temperature of 150 ° C. or lower, side reactions tend to be suppressed. In addition, by performing the reaction at a mixing temperature of −20 ° C. or higher, the mixing time tends to be shortened.

  By heating the block polyisocyanate obtained in the first step in the presence of a monohydric alcohol compound, the unreacted isocyanate group of the block polyisocyanate reacts with the active hydrogen in the monohydric alcohol compound, resulting in storage stability. A block polyisocyanate composition having improved properties can be obtained.

  In the present embodiment, in the block polyisocyanate composition, the polyisocyanate is blocked with a blocking agent so as to form a urethane bond between the unreacted isocyanate group and the monohydric alcohol compound. Try to leave the isocyanate group of the reaction.

  Examples of methods for leaving unblocked isocyanate groups include, for example, a method in which the amount of blocking agent added in advance is less than the molar amount of isocyanate groups in polyisocyanate, a method in which the amount of blocked reaction catalyst added is controlled, reaction temperature or reaction time. The method of controlling etc. are mentioned. These methods may be used alone or in combination.

  Moreover, the method of forming a urethane bond between the isocyanate group of block polyisocyanate and a monohydric alcohol compound can also be taken by the method of adding the said blocking agent and a monohydric alcohol compound simultaneously.

  By the above method, the block polyisocyanate composition in which the unreacted isocyanate group in block polyisocyanate and the monohydric alcohol compound formed the urethane bond can be produced | generated.

In the present embodiment, the block polyisocyanate is heated in the presence of a monohydric alcohol compound having an alkyl group having 4 or more carbon atoms, thereby promoting the transesterification reaction and improving the storage stability. Further, the alcohol desorbed by the transesterification reaction is removed by heating at the same time, so that the proportion of the alkyl group having 4 or more carbon atoms in the R ₁ and R ₂ in the formula (V) described above is the ratio of the present embodiment. The range can be adjusted, and the storage stability and compatibility tend to be improved.

The heating conditions for promoting the transesterification reaction may be any conditions that cause transesterification of R ₁ and R ₂ in the above formula (V), and can be adjusted at a desired temperature and time. However, a preferable heating temperature is −20 ° C. or higher and 150 ° C. or lower, and more preferably 50 ° C. or higher and 100 ° C. or lower. Moreover, preferable heating time is 0.2 hour or more and 8 hours or less, More preferably, it is 0.5 hour or more and 5 hours or less.

  The block polyisocyanate composition produced in the above process can achieve both low-temperature curability, storage stability, and compatibility.

  On the other hand, from polyisocyanate derived from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, malonic acid diester compounds, and if necessary blocking agents other than malonic acid diester compounds, A block polyisocyanate composition may be produced by separately mixing a block polyisocyanate containing a large amount of methanetetracarbonyl structure with the produced block polyisocyanate. For example, the block polyisocyanate obtained by the same process as the 1st process and the 2nd process is mixed with the block polyisocyanate obtained by separately producing the methanetetracarbonyl structure content ratio as the 3rd process. The methane tetracarbonyl structure content ratio of the entire block polyisocyanate composition obtained is adjusted.

  A block polyisocyanate having a high methanetetracarbonyl structure content ratio obtained separately is prepared by adjusting the molar ratio of the malonic acid diester compound to 0.5 or less and 0.9 or less of the isocyanate group of the polyisocyanate. It can manufacture by performing the process similar to 1 process. The lower limit of the molar ratio is more preferably 0.55, still more preferably 0.60, and still more preferably 0.65. The upper limit of the molar ratio is more preferably 0.85, further preferably 0.80, and still more preferably 0.75. By setting the lower limit of the molar ratio to 0.5 or more, gelation during the reaction tends to be suppressed. By setting the upper limit of the molar ratio to 1.0 or less, methanetetracarbonyl There is a tendency that the generation amount of the structure can be increased.

  In addition, it is preferable that the block polyisocyanate having a high methanetetracarbonyl structure ratio is mixed and reacted as a step similar to the second step after the reaction of the polyisocyanate and the malonic acid diester compound.

  The average number of isocyanate groups of the polyisocyanate used for the block polyisocyanate having a high methanetetracarbonyl structure content ratio is preferably 1.0 or more and 4.0 or less. The lower limit of the average number of isocyanate groups is more preferably 1.5, still more preferably 1.7, and even more preferably 1.9. The upper limit of the average number of isocyanate groups is more preferably 3.0, still more preferably 2.5, and even more preferably 2.0. When the lower limit value of the average number of isocyanate groups is 1.0 or more, the production ratio of the methanetetracarbonyl structure tends to be increased, and the upper limit value of the average number of isocyanate groups is 4.0 or less. There is a tendency that gelation during the production of the methanetetracarbonyl structure can be suppressed.

  The mixing temperature in the third step is preferably -20 ° C or higher and 150 ° C or lower, more preferably 0 ° C or higher and 100 ° C or lower, more preferably 40 ° C or higher and 80 ° C or lower. The side reaction tends to be suppressed by mixing at a mixing temperature of 150 ° C. or lower, and the mixing time tends to be shortened by mixing at −20 ° C. or higher.

(Additive)
Various organic solvents can be added as additives to the block polyisocyanate composition of the present embodiment according to the purpose and application.

  The organic solvent to be added is not particularly limited. For example, aliphatic hydrocarbon solvents such as hexane, heptane, and octane; alicyclic hydrocarbon solvents such as cyclohexane and methylcyclohexane; acetone, methyl ethyl ketone, methyl isobutyl ketone, Ketone solvents such as cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, methyl lactate, and ethyl lactate; aromatics such as toluene, xylene, diethylbenzene, mesitylene, anisole, benzyl alcohol, phenyl glycol, chlorobenzene Family solvents: glycosyl such as ethylene glycol monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether Ether solvents such as diethyl ether, tetrahydrofuran and dioxane; halogenated hydrocarbon solvents such as dichloromethane, 1,2-dichloroethane and chloroform; pyrrolidone solvents such as N-methyl-2-pyrrolidone; N, N An amide solvent such as dimethylacetamide and N, N-dimethylformamide; a sulfoxide solvent such as dimethyl sulfoxide; a lactone solvent such as γ-butyrolactone; an amine solvent such as morpholine; and a mixture thereof.

  Furthermore, you may add another block polyisocyanate which consists of a multimer of diisocyanates other than aliphatic and alicyclic diisocyanate to the block polyisocyanate composition of this embodiment in arbitrary ratios. In that case, the block agent bonded may be the same as or different from the block polyisocyanate.

  In addition, the block polyisocyanate composition of the present embodiment includes a curing accelerating catalyst, an antioxidant, an ultraviolet absorber, a light stabilizer, a pigment, a leveling agent, a plasticizer, a rheology control agent, a surface activity, depending on the purpose and application. Various additives such as an agent can be contained.

  Although it does not specifically limit as said hardening acceleration | stimulation catalyst, For example, tin-type compounds, such as dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, dimethyltin dineodecanoate, bis (2-ethylhexanoic acid) tin; Zinc compounds such as zinc ethylhexanoate and zinc naphthenate; titanium compounds such as titanium 2-ethylhexanoate and titanium diisopropoxybis (ethylacetonate); cobalt compounds such as cobalt 2-ethylhexanoate and cobalt naphthenate; Bismuth compounds such as bismuth 2-ethylhexanoate and bismuth naphthenate; zirconium compounds such as zirconium tetraacetylacetonate, zirconyl 2-ethylhexanoate and zirconyl naphthenate; amine compounds and the like.

  Although it does not specifically limit as said antioxidant, For example, a hindered phenol type compound, a phosphorus compound, a sulfur type compound, etc. are mentioned.

  Although it does not specifically limit as said ultraviolet absorber, For example, a benzotriazole type compound, a triazine type compound, a benzophenone type compound etc. are mentioned.

  The light stabilizer is not particularly limited, and examples thereof include hindered amine compounds, benzotriazole compounds, triazine compounds, benzophenone compounds, and benzoate compounds.

  The pigment is not particularly limited, and examples thereof include titanium oxide, carbon black, indigo, quinacridone, pearl mica, and aluminum.

  Although it does not specifically limit as said leveling agent, For example, silicone oil etc. are mentioned.

  The plasticizer is not particularly limited, and examples thereof include phthalic acid esters, phosphoric acid compounds, and polyester compounds.

  Although it does not specifically limit as said rheology control agent, For example, a hydroxyethyl cellulose, a urea compound, a microgel, etc. are mentioned.

  Although it does not specifically limit as said surfactant, For example, a well-known anionic surfactant, a cationic surfactant, an amphoteric surfactant etc. are mentioned.

  Moreover, in the polyisocyanate composition and the block polyisocyanate composition according to this embodiment, the content of the other additives described above is preferably 0 to 80% by mass, and preferably 0 to 70% by mass. Preferably, it is 0 to 60% by mass.

[One-pack type coating composition]
The one-component coating composition of the present embodiment includes the block polyisocyanate composition of the present embodiment and at least one of a polyol, a polyamine, and an alkanolamine. Moreover, it is preferable that a one-pack type coating composition contains a polyol at least. In order to improve the storage stability of the one-component coating composition, it is preferable that the block polyisocyanate composition of the present embodiment further contains the above-described monohydric alcohol compound.

  The block polyisocyanate composition is preferably a main component of the one-part coating composition together with at least one of polyol, polyamine and alkanolamine.

  Specific examples of the polyol are not particularly limited, and examples thereof include polyester polyol, acrylic polyol, polyether polyol, polyolefin polyol, fluorine polyol, polycarbonate polyol, and polyurethane polyol.

  The polyester polyol is not particularly limited, but for example, a dibasic acid selected from the group of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid and the like. Polyester polyol and polyhydric alcohol obtained by a condensation reaction of a single or mixture with a polyhydric alcohol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane and glycerin And polycaprolactones obtained by ring-opening polymerization of ε-caprolactone using.

  The acrylic polyol is not particularly limited, but for example, an ethylenically unsaturated bond-containing monomer having a hydroxyl group alone or a mixture thereof, and another ethylenically unsaturated bond-containing monomer copolymerizable therewith or It is obtained by copolymerizing with a mixture.

  The polyether polyols are not particularly limited. For example, a polybasic hydroxy compound is used alone or as a mixture, for example, a hydroxide such as lithium, sodium or potassium, an alcoholate, or a strongly basic catalyst such as alkylamine. , Polyether polyols obtained by adding a single or mixture of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide, etc .; obtained by reacting alkylene oxide with a polyfunctional compound such as ethylenediamine Polyether polyols; so-called polymer polyols obtained by polymerizing acrylamide or the like using these polyether polyols as media.

  The polyolefin polyol is not particularly limited, and examples thereof include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene. The number of hydroxyl groups (average number of hydroxyl groups) possessed by one statistical molecule of polyol is preferably 2.0 or more. It exists in the tendency which can suppress the fall of the crosslinking density of the obtained coating film because the hydroxyl group average number of a polyol is 2.0 or more.

  The fluorine polyol is a polyol containing fluorine in the molecule and is not particularly limited. For example, fluoroolefins, cyclovinyl ethers, hydroxyalkyls disclosed in JP-A-57-34107 and JP-A-61-275111. Examples thereof include copolymers such as vinyl ether and vinyl monocarboxylic acid.

  Polycarbonate polyols are not particularly limited. For example, low molecular carbonate compounds such as dialkyl carbonates such as dimethyl carbonate, alkylene carbonates such as ethylene carbonate, diaryl carbonates such as diphenyl carbonate, and the low molecular weight compounds used in the above-described polyester polyols. Examples thereof include those obtained by condensation polymerization of polyols.

  Although a polyurethane polyol is not specifically limited, For example, it can be obtained by making a polyol and polyisocyanate react.

  The hydroxyl value per resin of the polyol is preferably 10 mgKOH / resin g or more and 300 mgKOH / resin g or less. When the hydroxyl value per resin is 10 mg KOH / resin g or more, the crosslinking density is suppressed from decreasing, and the target physical properties of this embodiment tend to be sufficiently achieved. On the other hand, when the hydroxyl value per resin is 300 mgKOH / resin g or less, an excessive increase in the crosslinking density is suppressed, and the mechanical properties of the coating film tend to be maintained at a high level.

  The acid value per resin of the polyol is preferably 5.0 mgKOH / resin g to 150 mgKOH / resin g, more preferably 8.0 mgKOH / resin g to 120 mgKOH / resin g, and still more preferably 10 mgKOH / resin. The resin g is 100 mgKOH / resin g or less. When the acid value is 5.0 mgKOH / resin g or more, the water dispersibility tends to be kept high, and when it is 150 mgKOH / resin g or less, the decrease in water resistance of the coating film is suppressed. It tends to be possible.

  Among the polyols listed above, acrylic polyol and polyester polyol are more preferable. In the coating composition in the case of using a polyol, the equivalent ratio of the blocked isocyanate group to the hydroxyl group of the polyol is preferably set to 10: 1 to 1:10.

  As the polyamine, those having two or more primary amino groups or secondary amino groups in one molecule are preferably used, and those having three or more in one molecule are more preferable.

  Moreover, alkanolamine here means the compound which has an amino group and a hydroxyl group in 1 molecule. The alkanolamine is not particularly limited, and examples thereof include monoethanolamine, diethanolamine, aminoethylethanolamine, N- (2-hydroxypropyl) ethylenediamine, mono-, di- (n- or iso-) propanolamine, and ethylene glycol. -Bis-propylamine, neopentanolamine, and methylethanolamine.

  The one-pack type coating composition containing the block polyisocyanate composition of the present embodiment may contain a known melamine resin, epoxy resin, or polyurethane resin. Moreover, when the polyol mentioned above has a carboxyl group, an oxazoline group containing compound and a carbodiimide group containing compound can be contained. Moreover, when the polyol mentioned above has a carbonyl group, a hydrazide group containing compound and a semicarbazide group containing compound can be contained. These compounds can be blended not only alone but also two or more compounds.

  The one-component coating composition of the present embodiment is optionally provided with an antioxidant such as hindered phenol, an ultraviolet absorber such as benzotriazole and benzophenone, and a pigment such as titanium oxide, carbon black, indigo and quinacridone. Pearl mica, metal powder pigments such as aluminum, rheology control agents such as hydroxyethyl cellulose, urea compounds, microgels, and curing accelerators such as tin compounds, zinc compounds, amine compounds, etc.

[Coated article]
The coated article of this embodiment is coated with the one-component coating composition of this embodiment. For example, with the one-part coating composition of the present embodiment, by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, etc., it can be made into materials such as steel, surface-treated steel plates and other metals and plastics, inorganic materials, etc. , Primer, intermediate coating, or top coating is suitably applied to obtain a coated article. This one-pack type coating composition further imparts cosmetic properties, weather resistance, acid resistance, rust resistance, chipping resistance, adhesion, etc. to pre-coated metal, automobile coating, plastic coating, etc. including rust-proof steel sheets. Is preferably used. The one-component coating composition is also useful as a raw material for urethane such as adhesives, pressure-sensitive adhesives, elastomers, foams, and surface treatment agents.

[Coating]
The coating film of this embodiment is formed by the one-component coating composition of this embodiment. That is, the one-component coating composition of the present embodiment forms a coating film of the present embodiment through a baking process after coating by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, etc. Can do. The one-pack type coating composition used for forming this coating film is preferably subjected to a baking step to form a crosslinked coating film. The crosslinked coating film after curing of the one-pack type coating composition has polar groups such as amide bonds and ester bonds derived from blocked isocyanate groups, as well as urethane bonds derived from polyisocyanates before blocking reaction. Therefore, the cross-linked coating film formed from the one-pack type coating composition of the present embodiment is subjected to layer coating or recoating in addition to chemical resistance, heat resistance, water resistance, etc., which are characteristics of general urethane cross-linked coating films. When performed, hydrogen bonding between layers becomes possible, and the adhesion between layers is excellent. Even in the coating film in which the crosslinked structure is not completely formed after the baking step, the coating film has the above polar group, so that it is excellent in adhesion as well as the crosslinked coating film at the time of lamination coating or recoating.

  In addition, when several layers of coating liquid are laminated by wet-on-wet as in the coating of a new car line of an automobile, an organic amine compound is present in the coating composition of this embodiment or in the crosslinked coating film after curing. There is also the possibility of acting as a catalyst for the crosslinking reaction of the lower layer or the upper layer.

[Thermosetting composition, cured product]
The thermosetting composition of this embodiment contains the block polyisocyanate composition and a polyvalent active hydrogen compound. A cured product can be obtained by heat-curing the thermosetting composition. Specifically, the thermosetting composition of this embodiment can be produced by mixing the block polyisocyanate composition with a polyvalent active hydrogen compound. Moreover, by heating the thermosetting composition of this embodiment, block polyisocyanate and the active hydrogen in a polyvalent active hydrogen compound can transesterify, and it can be set as hardened | cured material.

  The thermosetting composition can be obtained by mixing a block polyisocyanate composition as a main component with a polyvalent active hydrogen compound. The cured product of the thermosetting composition of the present embodiment is heated to react the polyisocyanate composition described above with the reaction product of the malonic acid diester or β ketoester compound described above and the activity in the polyvalent active hydrogen compound. It can be obtained by transesterification with hydrogen.

  Hereinafter, the polyvalent active hydrogen compound that can be used in the thermosetting composition according to the present embodiment will be described.

  The polyvalent active hydrogen compound of this embodiment is a compound in which two or more active hydrogens are bonded in the molecule. Although it does not specifically limit as an example of an active hydrogen compound, For example, a polyol, a polyamine, an alkanolamine, and a polythiol are mentioned, A polyol is preferable.

  Although it does not specifically limit as said polyamine, For example, diamines, such as ethylenediamine, propylenediamine, butylenediamine, triethylenediamine, hexamethylenediamine, 4,4'-diaminodicyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine; Chain polyamines having three or more amino groups such as bishexamethylenetriamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentamethylenehexamine, tetrapropylenepentamine; 1,4,7,10,13,16 -Hexaazacyclooctadecane, 1,4,7,10-tetraazacyclodecane, 1,4,8,12-tetraazacyclopentadecane, 1,4,8,11-tetraazacyclotetradecane, etc. Jo polyamines and the like.

  The alkanolamine is not particularly limited, and examples thereof include monoethanolamine, diethanolamine, triethanolamine, aminoethylethanolamine, N- (2-hydroxypropyl) ethylenediamine, mono-, di- (n- or iso-). ) Propanolamine, ethylene glycol-bis-propylamine, neopentanolamine, methylethanolamine and the like.

  The polythiol is not particularly limited, and examples thereof include bis- (2-hydrothioethyloxy) methane, dithioethylene glycol, dithioerythritol, and dithiothreitol.

  Although it does not specifically limit as said polyol, For example, polyester polyol, acrylic polyol, polyether polyol, polyolefin polyol, fluorine polyol, polycarbonate polyol, polyurethane polyol, and an epoxy resin are mentioned.

  Although it does not specifically limit as said polyester polyol, For example, polyester polyol and polycaprolactone are mentioned. The polyester polyol is not particularly limited, and can be obtained, for example, by a condensation reaction between a dibasic acid alone or a mixture and a polyhydric alcohol alone or a mixture. The dibasic acid is not particularly limited, but for example, one kind selected from the group consisting of succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid carboxylic acid Or 2 or more types of dibasic acids are mentioned. In addition, the polyhydric alcohol is not particularly limited. For example, one or two or more polyhydric alcohols selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylol propane, and glycerin may be used. Can be mentioned. Moreover, although the said polycaprolactone is not specifically limited, For example, it is obtained by ring-opening polymerization of (epsilon) -caprolactone using a polyhydric alcohol.

  The acrylic polyol is not particularly limited. For example, an ethylenically unsaturated bond-containing monomer having a hydroxyl group alone or a mixture thereof and another ethylenically unsaturated bond-containing monomer copolymerizable therewith can be used. Those obtained by copolymerization alone or with a mixture may be mentioned.

  Although it does not specifically limit as said polyether polyol, For example, using strongly basic catalysts, such as hydroxide, lithium, sodium, potassium, etc .; alcoholate, alkylamine, it becomes single or a mixture of a polyhydric hydroxy compound, Polyether polyols obtained by adding a single or mixture of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide or the like; polyalkylene compounds obtained by reacting alkylene oxide with a polyfunctional compound such as ethylenediamine Ether polyols; so-called polymer polyols obtained by polymerizing acrylamide or the like using the above polyethers as media.

  Although it does not specifically limit as said polyolefin polyol, For example, the polybutadiene which has 2 or more of hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene are mentioned.

  The fluorine polyol is not particularly limited, and is, for example, a polyol containing fluorine in the molecule. For example, fluoroolefins and cycloolefins disclosed in JP-A-57-34107 and JP-A-61-275111 are disclosed. Examples thereof include copolymers such as vinyl ether, hydroxyalkyl vinyl ether, and monocarboxylic acid vinyl ester.

  Although it does not specifically limit as said polycarbonate polyol, For example, low molecular carbonate compounds, such as dialkyl carbonates, such as dimethyl carbonate, alkylene carbonates, such as ethylene carbonate, diaryl carbonates, such as diphenyl carbonate, and the low molecule used for the above-mentioned polyester polyol Examples thereof include those obtained by condensation polymerization of polyols.

  The polyurethane polyol can be obtained by a conventional method, for example, by reacting a polyol with a polyisocyanate.

  The epoxy resin is not particularly limited as long as it is a resin having two or more epoxy groups in one molecule, and a known one can be used. Examples of the epoxy resin include a bisphenol type epoxy resin obtained by adding epoxychlorohydrin to bisphenol, a novolak type epoxy resin obtained by adding epichlorohydrin to a phenol novolac resin, and polyethylene glycol diglycidyl ether. The epoxy resin can be used after being dispersed in water as necessary.

  Of the polyols listed above, acrylic polyols and polyester polyols are preferred.

  The hydroxyl value of the polyol is preferably 10 mgKOH / g or more and 300 mgKOH / g or less per resin in terms of crosslink density and mechanical properties of the cured product. When the hydroxyl value per resin is 10 mgKOH / resin g or more, the crosslinking density is suppressed from decreasing, and the target physical properties of this embodiment tend to be sufficiently achieved. On the other hand, when the hydroxyl value per resin is 300 mgKOH / resin g or less, the crosslinking density is prevented from excessively increasing, and the mechanical properties of the coating film tend to be maintained at a high level. The hydroxyl value can be determined by a titration method.

  In the curable composition of the present embodiment, the molar ratio of the blocked isocyanate group to the active hydrogen group (isocyanate group: active hydrogen group) is preferably set to 10: 1 to 1:10.

  The curable composition of this embodiment can further contain other hardening | curing agents, such as a melamine type hardening | curing agent and an epoxy-type hardening | curing agent.

  Although it does not specifically limit as a melamine type hardening | curing agent, For example, the fully alkyl etherified melamine resin, the methylol group type melamine resin, and the imino group type melamine resin which has an imino group in part are mentioned.

  When a melamine curing agent is used in combination as a curing agent, it is effective to further add an acidic compound. Although it does not specifically limit as a specific example of an acidic compound, For example, carboxylic acid, a sulfonic acid, acidic phosphoric acid ester, and phosphorous acid ester are mentioned.

  The carboxylic acid is not particularly limited, and examples thereof include acetic acid, lactic acid, succinic acid, oxalic acid, maleic acid, and decanedicarboxylic acid.

  Although it does not specifically limit as a sulfonic acid, For example, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and dinonyl naphthalene disulfonic acid are mentioned.

  The acidic phosphate ester is not particularly limited, and examples thereof include dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, dilauryl phosphate, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, and monooctyl phosphate.

  The phosphite is not particularly limited, and examples thereof include diethyl phosphite, dibutyl phosphite, dioctyl phosphite, dilauryl phosphite, monoethyl phosphite, monobutyl phosphite, monooctyl phosphite, and monolauryl phosphite. Fight is mentioned.

  Although it does not specifically limit as an epoxy-type hardener, For example, an aliphatic polyamine, an alicyclic polyamine, an aromatic polyamine, an acid anhydride, a phenol novolak, a polymercaptan, an aliphatic tertiary amine, an aromatic tertiary amine, imidazole Examples include compounds and Lewis acid complexes.

  Although it does not specifically limit as an epoxy-type hardener, For example, an aliphatic polyamine, an alicyclic polyamine, an aromatic polyamine, an acid anhydride, a phenol novolak, a polymercaptan, an aliphatic tertiary amine, an aromatic tertiary amine, imidazole Examples thereof include a compound and a Lewis acid complex.

[Usage]
The block polyisocyanate composition of the present embodiment is, for example, a curable composition such as a coating composition, a pressure-sensitive adhesive composition, an adhesive composition or a casting composition; various surface treatment compositions such as a fiber treatment agent. Various elastomer compositions; crosslinking agents such as foam compositions; modifiers; can be used as additives.

  The coating composition containing the block polyisocyanate composition of this embodiment is suitably used as a primer, intermediate coating or top coating on various materials by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, etc. The In addition, this coating composition further imparts cosmetic properties, weather resistance, acid resistance, rust resistance, chipping resistance, adhesion, etc. to pre-coated metal, automobile coating, plastic coating, etc. that contain a rust-proof steel plate. Preferably used.

  Fields of use of the pressure-sensitive adhesive composition and adhesive composition containing the block polyisocyanate composition of the present embodiment include automobiles, building materials, home appliances, woodworking, solar cell laminates, and the like. Among them, optical members for liquid crystal displays of home appliances such as televisions, personal computers, digital cameras, and mobile phones exhibit various functions. Therefore, it is necessary to laminate films and plates of various adherends. Since the material used between the films and plates of various adherends requires sufficient tackiness or adhesiveness, use of the pressure-sensitive adhesive composition and adhesive composition containing the block polyisocyanate composition of the present embodiment Preferred as an example.

  The adherend to which the curable composition containing the block polyisocyanate composition of the present embodiment can be used is not particularly limited. For example, glass; various metals such as aluminum, iron, galvanized steel, copper, and stainless steel Porous materials such as wood, paper, mortar, and stone materials; Fluorine coating, urethane coating, acrylic urethane coating, etc .; Sealing materials such as silicone-based cured products, modified silicone-based cured products, and urethane-based cured products Products; Rubbers such as vinyl chloride, natural rubber, synthetic rubber; Leathers such as natural leather and artificial leather; Fibers such as plant fiber, animal fiber, carbon fiber and glass fiber; Non-woven fabric, polyester, acrylic, polycarbonate Films and plates of resins such as triacetyl cellulose and polyolefin; UV curable acrylic resin layer, printing ink Key, and a inks such as UV inks.

  Hereinafter, the present embodiment will be described in more detail by way of examples. However, the present embodiment is not limited to these examples. Below, the measurement / evaluation method of various physical properties is demonstrated.

(Physical property 1) NCO content (mass%)
The NCO content (isocyanate content, mass%) of the polyisocyanate was measured as follows. To the Erlenmeyer flask, 1 to 3 g of the polyisocyanate produced in the production example was precisely weighed (Wg) and 20 mL of toluene was added to completely dissolve the polyisocyanate. Thereafter, 10 mL of a 2N di-n-butylamine toluene solution was added, thoroughly mixed, and allowed to stand at room temperature for 15 minutes. Further, 70 mL of isopropyl alcohol was added to this solution and mixed thoroughly. This solution was titrated with a 1 N hydrochloric acid solution (factor F) using an indicator to obtain a titration value V ₂ mL. The same titration operation was performed without using polyisocyanate, and a titration value V ₁ mL was obtained. From the obtained titration value V ₂ mL and titration value V ₁ mL, the NCO content of the polyisocyanate was calculated based on the following formula.
NCO content = (V ₁ −V ₂ ) × F × 42 / (W × 1000) × 100

(Physical property 2) Viscosity (mPa · s)
The viscosity of the polyisocyanate was measured at 25 ° C. using an E-type viscometer (manufactured by Tokimec). In the measurement, a standard rotor (1 ° 34 ′ × R24) was used. The number of rotations was as follows.
100r. p. m. (If less than 128 mPa.s)
50r. p. m. (128 mPa.s or more and less than 256 mPa.s)
20r. p. m. (In the case of 256 mPa.s or more and less than 640 mPa.s)
10r. p. m. (In the case of 640 mPa.s or more and less than 1280 mPa.s)
5r. p. m. (If it is 1280 mPa.s or more and less than 2560 mPa.s)
2.5r. p. m. (2560mPa.s or more and less than 5120mPa.s)
1.0r. p. m. (5120 mPa.s or more and less than 10240 mPa.s)
0.5r. p. m. (In the case of 10240 mPa.s or more and less than 20480 mPa.s)

(Physical property 3) Number average molecular weight The number average molecular weight of polyisocyanate was calculated | required by the number average molecular weight of the polystyrene reference | standard by the gel permeation chromatograph (henceforth "GPC") measurement using the following apparatus.
Equipment: “HLC-8120GPC” (trade name) manufactured by Tosoh Corporation
Column: "TSKgel SuperH1000" (product name) x 1 manufactured by Tosoh Corporation
"TSKgel SuperH2000" (trade name) x 1
"TSKgel SuperH3000" (trade name) x 1 Carrier: Tetrahydrofuran Detection method: Differential refractometer

Moreover, the number average molecular weight of the polyol was calculated | required by the number average molecular weight of the polystyrene reference | standard by the following GPC measurement.
Equipment: “HLC-8120GPC” (trade name) manufactured by Tosoh Corporation
Column: “TSKgel SuperHM-H” (trade name) x 2 manufactured by Tosoh Corporation Carrier: N, N-dimethylformamide Detection method: differential refractometer

(Physical property 4) Residual HDI concentration (mass%)
The residual HDI concentration of the polyisocyanate was determined as follows. First, a 20 mL sample bottle was placed on a digital balance, and about 1 g of the sample was precisely weighed. Next, 0.03-0.04 g of nitrobenzene (internal standard solution) was added and precisely weighed. Finally, after adding about 9 mL of ethyl acetate, the lid was tightly mixed well to prepare the sample. The adjustment liquid was quantitatively analyzed by gas chromatography under the following conditions.
Apparatus: “GC-8A” manufactured by SHIMADZU
Column: “Silicon OV-17” manufactured by Shinwa Kako
Column oven temperature: 120 ° C
Injection / detector temperature: 160 ° C

(Physical property 5) Average number of isocyanate groups The average number of isocyanate groups of the polyisocyanate was calculated by the following general formula from the number average molecular weight of (Physical property 1) and the NCO content (isocyanate concentration) of (Physical property 3).

(Physical property 6) Effective NCO content (mass%)
The effective NCO content of the block polyisocyanate was determined as follows. Here, the effective NCO content (% by mass) is to quantify the amount of blocked isocyanate groups that can participate in the crosslinking reaction present in the blocked polyisocyanate composition after the blocking reaction. Expressed as mass%, it was calculated by the following formula.
{(Solid content (mass%) of block polyisocyanate composition) × (mass of polyisocyanate used in reaction × isocyanate group content% of precursor polyisocyanate)} / (block polyisocyanate composition after blocking reaction) Resin mass)
In addition, when the sample was diluted with a solvent etc., the value in the diluted state was described.

(Physical property 7) Solid content concentration (mass%)
After precisely weighing an aluminum dish having a bottom diameter of 38 mm, the block polyisocyanate composition of Example or Comparative Example was precisely weighed with about 1 g on the aluminum dish (W1), and the block polyisocyanate composition was made to a uniform thickness. After adjustment, it was kept in an oven at 105 ° C. for 1 hour. After the aluminum dish reached room temperature, the block polyisocyanate composition remaining on the aluminum dish was precisely weighed (W2).
Solid concentration = W2 / W1 × 100

(Physical property 8) Mole ratio between keto body and enol body The mole ratio of keto body / enol body was determined by 1H-NMR measurement using “Biospin Avance 600” (trade name) manufactured by Bruker. Specific measurement conditions were as follows.
Apparatus: “Biospin Avance 600” (trade name) manufactured by Bruker
Solvent: Deuterated chloroform Accumulated number: 256 Sample concentration: 5% by mass
Chemical shift standard: Tetramethylsilane was 0 ppm.

The integrated value of the following signals was divided by the number of hydrogen being measured, and each molar ratio was determined from the value.
Keto NH protons: (diethyl malonate represented by the following formula (VIII)) around 7.3 ppm, (ethyl acetoacetate represented by the following formula (IX)) around 7.2 ppm
Enol NH protons: (diethyl malonate represented by the following formula (X)) around 9.8 ppm, (ethyl acetoacetate represented by the following formula (XI)) around 9.2 ppm

(Physical property 9) Methanetetracarbonyl structure ratio (mol%)
The methanetetracarbonyl structure ratio of the block polyisocyanate composition was determined as follows. By measurement of ¹ H-NMR using “Avance 600” (trade name) manufactured by Bruker Biospin, methane tetracarbonyl structure / (methane tetracarbonyl structure + keto form of methane tricarbonyl structure + enol form of methane tricarbonyl structure) The molar ratio was determined. Specific measurement conditions were as follows.
Apparatus: “Avance600” (trade name) manufactured by BrukerBiospin
Solvent: Deuterated chloroform Accumulated number: 256 Sample concentration: 5.0% by mass
Chemical shift standard: Tetramethylsilane was 0 ppm.

The integral values of the following signals were divided by the number of carbons being measured, and each molar ratio was determined from the value.
-Keto NH proton of methanetricarbonyl structure (structure represented by the following formula (III)): around 7.3 ppm: integral value / 1
Enol NH proton of methanetricarbonyl structure (structure represented by the following formula (IV)): around 9.8 ppm: integral value / 1
-NH proton of methanetetracarbonyl structure (structure represented by the following formula (VII)): around 8.0 ppm: integral value / 2

(Physical property 10) Molar ratio of urethane bond between isocyanate group and monohydric alcohol compound ¹ H-NMR of the block polyisocyanate composition obtained in Synthesis Examples 2 to 7 was measured, and the monohydric alcohol compound and the isocyanate group were bonded. The amino group (near 4.8 ppm) resulting from the urethane bond, and the amino group adjacent to the amide formed by combining the isocyanate group and diethyl malonate (near 7.3 ppm: keto body) , Around 8.0 ppm: diamide diester, around 9.8 ppm: enol), and an amino group adjacent to the amide formed by combining an isocyanate group with ethyl acetoacetate (around 7.2 ppm: keto) Body, around 9.2 ppm: enol body) from the area of the peak, It was determined the molar ratio of emission bonds.
Molar ratio of the urethane bond = (a) / ((a) + (b) + (c))
(B): Number of amino groups adjacent to the amide formed by combining an isocyanate group and diethyl malonate (= peak area around 7.3 ppm + peak area around 8.0 ppm / peak area around 2 + 9.8 ppm) : The peak at about 8.0 ppm (diamide diester) has two amino groups in one bond structure, so 1/2 of the peak area was taken as the number of bond structures) and the isocyanate group and malon The number of bond structures (number of moles) with the acid diester compound.
(C): Isocyanate group determined from the number of amino groups adjacent to the amide formed by combining an isocyanate group and ethyl acetoacetate (= peak area near 7.2 ppm + peak area around 9.2 ppm) Number of bond structures with acetoacetate compound (number of moles).
(A): Isocyanate group and monovalent value determined from the number of amino groups (peak area in the vicinity of 4.8 ppm) resulting from a urethane bond obtained by combining an isocyanate group with n-butanol, isobutanol or isopropanol Number of urethane bond structures (number of moles) with alcohol compound.

(Physical Property 11) Molar Ratio of Blocked Isocyanate Structure Using each block polyisocyanate composition obtained in Examples and Comparative Examples as a sample, any of the terminal alkyl groups bonded to diethyl malonate is an alkyl having 4 to 8 carbon atoms. The molar ratio of the blocked isocyanate structure as a group (hereinafter referred to as “molar ratio M”) was determined as follows. Molar ratio M was determined by ¹ H-NMR measurement using “Avance 600” (trade name) manufactured by Bruker Biospin as follows. Specific measurement conditions were as follows.
Apparatus: “Avance600” (trade name) manufactured by BrukerBiospin
Solvent: Deuterated chloroform Accumulated number: 256 Sample concentration: 5.0% by mass
Chemical shift standard: Tetramethylsilane was 0 ppm.
The ¹ H-NMR of the block polyisocyanate composition was measured, and the molar fraction M was calculated from the following formula from the peak area caused by the OH group protons (16.4 to 16.6 ppm) of the enol form of malonic acid diester. Calculated.
Molar ratio M = a / b
a: Peak area of the proton, wherein at least one of the terminal alkyl groups is an alkyl group having 4 to 8 carbon atoms, b: Total peak area of the proton

(Evaluation 1) Low-temperature curability “Setalux 1152” (acrylic polyol, trade name manufactured by Nuplex Resins, hydroxyl value 138 mg KOH / resin g, solid content concentration 51 mass%) and block polyisocyanate composition, NCO / OH = 1 0 and blended with butyl acetate for Ford Cup No. 4 was adjusted to 20 seconds / 23 ° C. to obtain an α coating solution.

  The obtained α coating solution was applied to a PP plate with an air spray gun to a dry film thickness of 40 μm, dried at a temperature of 23 ° C. for 30 minutes, and baked at 90 ° C. for 20 minutes to obtain a cured coating film. .

The obtained cured coating film was baked, left at 20 ° C. for 1 hour, peeled off from the PP plate, immersed in acetone at 20 ° C. for 24 hours, and the value (gel fraction) of the undissolved part mass relative to the mass before immersion. Calculated and evaluated according to the following criteria.
◎: Gel fraction is 90% or more ○: Gel fraction is 80% or more and less than 90%,
Δ: Gel fraction is 70% or more and less than 80% ×: Gel fraction is less than 70%

(Evaluation 2) Adhesiveness with upper coating film The α coating solution obtained in the above (Evaluation 1) was applied to a mild steel plate with an air spray gun so that the dry film thickness was 40 μm, and the temperature was 23 ° C. After drying for 20 minutes, baking was performed at 90 ° C. for 20 minutes to obtain an α coating layer 1. The adhesion test with the mild steel sheet of the α coating layer 1 was performed according to JIS K5600-5-6. As a result, no peeling was observed, including some floats.

  “Setalux 1767” (acrylic polyol, trade name of Nuplex Resins, hydroxyl value 150 mg KOH / resin g, solid content 65 mass%) 70 parts, hexamethoxymethylated melamine resin “Cymel (registered trademark) 300” manufactured by Nippon Cytec Co., Ltd. After mixing 30 parts by mass and 1 part by mass of p-toluenesulfonic acid, the Ford Cup No. 4 was adjusted to 20 seconds / 23 ° C. to obtain a β coating solution.

Separately, the α coating solution obtained in the above (Evaluation 1) was applied to a mild steel plate with an air spray gun to a dry film thickness of 40 μm, dried at a temperature of 23 ° C. for 30 minutes, and then at 90 ° C. for 20 minutes. Baking was performed to obtain an α coating layer 2. The α coating layer 2 is coated with a β coating solution so as to have a dry film thickness of 40 μm, dried at a temperature of 23 ° C. for 30 minutes, and then baked at 140 ° C. for 30 minutes to form a multilayer coating having an α layer and a β layer. A membrane was obtained. The adhesion test of the obtained multilayer coating film was performed according to JIS K5600-5-6. Evaluation was made according to the following criteria.
◎: Peeling paint film, no lift ○: Partly lifted at the cut part △: Less than half peeled film ×: Half or more peeled film

(Evaluation 3) Compatibility The α coating solution obtained in the above (Evaluation 1) was applied to a glass plate with an air spray gun so as to have a dry film thickness of 80 μm. The film was dried at a temperature of 23 ° C. for 30 minutes, baked at 90 ° C. for 20 minutes, and then cooled. It observed visually and evaluated on the following reference | standard.
○: Transparent △: Slightly cloudy ×: Strongly cloudy

[Production Example 1] Polyisocyanate P-1
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel is placed in a nitrogen atmosphere, charged with 1100 parts by mass of HDI and 1.2 parts by mass of 1,3-butanediol, and reacted with stirring. The internal temperature was maintained at 80 ° C. for 2 hours. Thereafter, the temperature in the reactor was kept at 60 ° C., tetrabutylammonium acetate was added, and phosphoric acid was added when the NCO content of the reaction solution reached 41.3 mass% to stop the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporator, the NCO content was 21.0%, the viscosity at 25 ° C. was 3800 mPas, the residual HDI concentration was 0.2 mass%, and the average number of isocyanate groups was 3. .6 polyisocyanate P-1 was obtained.

[Production Example 2] Polyisocyanate P-2
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen blowing tube is placed in a nitrogen atmosphere, charged with 100 parts by mass of HDI and 3.3 parts by mass of trimethylolpropane. Hold for 2 hours at ° C. Thereafter, the temperature in the reactor was maintained at 60 ° C., tetrabutylammonium acetate was added, and phosphoric acid was added to stop the reaction when the NCO content of the reaction solution reached 36.3% by mass. After the reaction solution was filtered, unreacted HDI was removed using a thin film evaporator. A polyisocyanate P-2 having an NCO content of 19.5%, a viscosity at 25 ° C. of 25000 mPas, a residual HDI concentration of 0.2% by mass, and an average number of isocyanate groups of 5.1 was obtained.

[Production Example 3] Polyisocyanate P-3
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen blowing tube is placed in a nitrogen atmosphere, charged with 100 parts by mass of HDI, the temperature in the reactor is kept at 60 ° C. with stirring, and tetrabutylammonium acetate is added. When the NCO content of the reaction solution reached 43.8% by mass, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporator, the NCO content was 19.5%, the viscosity at 25 ° C. was 1700 mPas, 23.0%, the residual HDI concentration was 0.2 mass%, An isocyanurate type polyisocyanate P-3 having an isocyanate group average number of 3.2 was obtained.

[Example 1] Blocked polyisocyanate composition B-1
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen blowing tube is placed in a nitrogen atmosphere, 100 parts by mass of polyisocyanate P-1, 67 parts by mass of diethyl malonate, 14 parts by mass of ethyl acetoacetate, 39 parts by mass of n-butyl acetate was charged, 0.8 part by mass of a 28% sodium methylate solution was added at a rate of 0.16 parts by mass / minute at room temperature, and reacted at 60 ° C. for 6 hours. Thereafter, 74 parts by mass of 1-butanol was added and stirring was continued at that temperature for 2 hours. Block polyisocyanate composition B in which 0.8 part by mass of mono (2-ethylhexyl) phosphate is added thereto, the effective NCO content is 7.1%, the solid content concentration is 60% by mass, and the malonic diester adduct ratio is 80 mol%. -1 was obtained. ¹ H-NMR measurement of the obtained block polyisocyanate composition B-1 was carried out, the molar ratio of keto body and enol body in the block polyisocyanate composition, methanetetracarbonyl structure ratio in the isocyanate-malonic acid diester bond The molar ratio of the urethane bond between the isocyanate group and the monohydric alcohol compound and the molar ratio of the blocked isocyanate structure were quantified. Moreover, the above-described evaluations (Evaluation 1) to (Evaluation 3) were performed. The obtained results are shown in Table 1.

[Examples 2-6, Comparative Examples 1-2]
In Examples 2 to 6 and Comparative Examples 1 and 2, the block polyisocyanate compositions B-2 to B-6, B- were used in the same manner as in Example 1 except that the formulations shown in Table 1 or Table 2 were used. 8 to B-9 were obtained. Tables 1 and 2 show physical property values and evaluation results of the obtained block polyisocyanate composition.

[Example 7]
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen blowing tube is placed in a nitrogen atmosphere, 100 parts by mass of polyisocyanate P-1, 67 parts by mass of diethyl malonate, 14 parts by mass of ethyl acetoacetate, 39 parts by mass of n-butyl acetate was charged, 0.8 part by mass of 28% sodium methylate solution was added at room temperature at a rate of 0.05 part by mass / min, and reacted at 60 ° C. for 6 hours. Thereafter, 74 parts by mass of 1-butanol was added, and stirring was continued at that temperature for 2 hours while flowing nitrogen. Block polyisocyanate composition B in which 0.8 part by mass of mono (2-ethylhexyl) phosphate is added thereto, the effective NCO content is 7.1%, the solid content concentration is 60% by mass, and the malonic diester adduct ratio is 80 mol%. -7 was obtained. ¹ H-NMR measurement of the obtained block polyisocyanate composition B-7 was carried out, the molar ratio of keto body and enol body in the block polyisocyanate composition, methane tetracarbonyl structure ratio in the isocyanate-malonic acid diester bond The molar ratio of the urethane bond between the isocyanate group and the monohydric alcohol compound and the molar ratio of the blocked isocyanate structure were quantified. Moreover, the above-described evaluations (Evaluation 1) to (Evaluation 3) were performed. The obtained results are shown in Table 1.

[Comparative Example 3]
In the formulation shown in Table 2, a 28% sodium methylate solution was premixed with the blocking agents diethyl malonate and ethyl acetoacetate and the mixture was added slowly at room temperature as in Example 1. Block polyisocyanate composition B-10 was obtained. Table 2 shows the physical property values and evaluation results of the obtained block polyisocyanate composition.

  From the results of the above examples and comparative examples, the block polyisocyanate composition of the present embodiment has a low-temperature curability that can be cross-linked at a baking temperature of 100 ° C. or lower, while maintaining adhesion to the upper coating film. It was found to be excellent and compatible with the polyol.

[Synthesis method]
The block polyisocyanate compositions in Reference Examples and Comparative Reference Examples and the methods for synthesizing the polyisocyanates used for their synthesis are shown below.

(Synthesis Example 1)
(Synthesis of polyisocyanate)
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube and dropping funnel is placed in a nitrogen atmosphere, charged with 1000 g of hexamethylene diisocyanate (HDI), and the reactor temperature is maintained at 60 ° C. with stirring. did. Then, 2.1 g of tetramethylammonium acetate (2-butanol 5.0% by mass solution) was added as an isocyanuration reaction catalyst to carry out the reaction. After 4 hours, the reaction end point was confirmed by measuring the refractive index of the reaction solution, and 0.2 g of phosphoric acid (85 mass% aqueous solution) was added to stop the reaction.

  After filtering the reaction solution, unreacted HDI was removed using a thin film distillation apparatus to obtain a polyisocyanate having an isocyanurate group. The obtained polyisocyanate had a viscosity at 25 ° C. of 2500 mPa · s and an NCO group content of 22.2% by mass.

(Synthesis Example 2)
(Production of block polyisocyanate composition A)
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen blowing tube was placed in a nitrogen atmosphere, and 100 parts of the polyisocyanate obtained in Synthesis Example 1 and 42.3 parts of butyl acetate were charged, and diethyl malonate A mixture of 71.1 parts, ethyl acetoacetate 14.5 parts and 28% sodium methylate methanol solution 0.8 part was added at room temperature, and the reaction was continued at 80 ° C. for 1 hour. Thereafter, 76.0 parts of 1-butanol was added and stirred at 80 ° C. for 2 hours.

  Table 3 shows the effective NCO group content and molar ratio of the block polyisocyanate composition A in which the block polyisocyanate is 60% by mass.

(Synthesis Example 3)
(Production of block polyisocyanate composition B)
In the same apparatus as the block polyisocyanate composition A, 100 parts of polyisocyanate and 42.3 parts of butyl acetate were charged, 64.1 parts of diethyl malonate, 13.1 parts of ethyl acetoacetate, 28% sodium methylate methanol 0.8 parts of the mixture was added at room temperature and the reaction was continued at 80 ° C. for 1 hour. Thereafter, 84.0 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 2 hours while flowing nitrogen.

  Table 3 shows the effective NCO group content and molar ratio of the blocked polyisocyanate composition B having a block polyisocyanate content of 60% by mass.

(Synthesis Example 4)
(Production of block polyisocyanate composition C)
In the same apparatus as the block polyisocyanate composition A, 100 parts of polyisocyanate and 42.3 parts of butyl acetate were charged, 56.9 parts of diethyl malonate, 11.6 parts of ethyl acetoacetate, 28% sodium methylate methanol 0.8 parts of the mixture was added at room temperature and the reaction was continued at 80 ° C. for 1 hour. Thereafter, 93.0 parts of 1-butanol was added and stirred at 80 ° C. for 2 hours.

  Table 3 shows the effective NCO group content and molar ratio of the blocked polyisocyanate composition C having 60% by weight of the blocked polyisocyanate.

(Synthesis Example 5)
(Production of block polyisocyanate composition D)
In the same apparatus as the block polyisocyanate composition A, 100 parts of polyisocyanate and 42.3 parts of butyl acetate were charged, 56.9 parts of diethyl malonate, 11.6 parts of ethyl acetoacetate, 28% sodium methylate methanol 0.4 part of the mixture was added at room temperature and the reaction was continued at 80 ° C. for 0.5 hour. Thereafter, 93.0 parts of 1-butanol was added and stirred at 80 ° C. for 2 hours.

  Table 3 shows the effective NCO group content and molar ratio of the blocked polyisocyanate composition D having 60% by weight of the blocked polyisocyanate.

(Synthesis Example 6)
(Production of block polyisocyanate composition E)
In the same apparatus as the block polyisocyanate composition A, 100 parts of polyisocyanate and 42.3 parts of butyl acetate were charged, 71.1 parts of diethyl malonate, 14.5 parts of ethyl acetoacetate, 28% sodium methylate methanol 0.8 parts of the mixture was added at room temperature and the reaction was continued at 80 ° C. for 0.5 hours. Thereafter, 76.0 parts of 1-butanol was added and stirred for 2 hours at 80 ° C. while flowing nitrogen.

  Table 3 shows the effective NCO group content and molar ratio of the block polyisocyanate composition E having 60% by weight of the block polyisocyanate.

(Synthesis Example 7)
(Production of block polyisocyanate composition F)
A block polyisocyanate composition F was synthesized in the same manner as in Synthesis Example 2, except that the 28% sodium methylate methanol solution was changed to 1.5 parts.

Table 3 shows the effective NCO group content and molar ratio of the blocked polyisocyanate composition F having 60% by weight of the blocked polyisocyanate.
(Synthesis Example 8)
(Production of block polyisocyanate composition G)
A block polyisocyanate composition G was synthesized in the same manner as in Synthesis Example 2 except that the reaction temperature and the reaction time were 60 ° C. and 3 hours.

  Table 3 shows the effective NCO group content and molar ratio of the block polyisocyanate composition G having a block polyisocyanate content of 60% by mass.

(Synthesis Example 9)
(Production of block polyisocyanate composition H)
A block polyisocyanate composition H was synthesized in the same manner as in Synthesis Example 2 except that 1-butanol was changed to isobutanol.

  Table 3 shows the effective NCO group content and molar ratio of the block polyisocyanate composition H having a block polyisocyanate content of 60% by mass.

(Synthesis Example 10)
(Production of Block Polyisocyanate Composition I)
A block polyisocyanate composition I was synthesized in the same manner as in Synthesis Example 2 except that 76.0 parts of 1-butanol was changed to 61.0 parts of isopropanol.

  Table 3 shows the effective NCO group content and molar ratio of the blocked polyisocyanate composition I having 60% by weight of the blocked polyisocyanate.

(Synthesis Example 11)
(Production of block polyisocyanate composition J)
A block polyisocyanate composition J was synthesized in the same manner as in Synthesis Example 2 except that 4.0 parts of 28% sodium methylate methanol solution was added.

  Table 3 shows the effective NCO group content and molar ratio of the blocked polyisocyanate composition J having a block polyisocyanate content of 60% by mass.

(Synthesis Example 12)
(Production of block polyisocyanate composition K)
In the same apparatus as the block polyisocyanate composition A, 100 parts of polyisocyanate and 42.3 parts of butyl acetate were charged, 28.4 parts of diethyl malonate, 5.8 parts of ethyl acetoacetate, 28% sodium methylate methanol 0.8 parts of the mixture was added at room temperature and the reaction was continued at 80 ° C. for 0.5 hours. Thereafter, 127.4 parts of 1-butanol was added and stirred at 80 ° C. for 2 hours.

  Table 3 shows the effective NCO group content and molar ratio of the block polyisocyanate composition K having 60% by weight of the block polyisocyanate.

(Synthesis Example 13)
(Production of block polyisocyanate composition L)
A block polyisocyanate composition L was synthesized in the same manner as in Synthesis Example 2 except that the reaction temperature and reaction time were 80 ° C. and 0.2 hours.

  Table 3 shows the effective NCO group content and molar ratio of the block polyisocyanate composition L having 60% by weight of the block polyisocyanate.

(Synthesis Example 14)
(Production of block polyisocyanate composition M)
A block polyisocyanate composition M was synthesized in the same manner as in Synthesis Example 2 except that the reaction temperature and reaction time were changed to 80 ° C. and 6 hours.

  Table 3 shows the effective NCO group content and molar ratio of the blocked polyisocyanate composition M having a block polyisocyanate content of 60% by mass.

[Evaluation method]
The evaluation methods for various physical properties of the block polyisocyanate compositions in Reference Examples and Comparative Reference Examples are shown below.

(Evaluation 4) Curability Polyisocyanate composition and acrylic polyol (Setalux 1152, manufactured by Nuplex Resins, hydroxyl value 70.4 mg KOH / g (solid), solid content 61% by mass) at NCO / OH = 1.0 The resulting mixture was diluted with butyl acetate to a solid content of 50% to prepare a coating composition.
The obtained coating composition was applied to an PP plate by an applicator so that the film thickness after drying was 60 μm. After drying at a temperature of 23 ° C. for 30 minutes and baking at 100 ° C. for 30 minutes, the coating film was peeled off from the plate. The residual film ratio (gel fraction) when immersed in acetone at 23 ° C. for 24 hours was measured.
<Evaluation criteria>
○: Gel fraction is 90% or more Δ: Gel fraction is 80% or more and less than 90% ×: Gel fraction is less than 80%

(Evaluation 5) Compatibility (Evaluation 4) The transparency after applying the coating composition prepared by the same method as in the evaluation of curability to the glass plate with an applicator to a film thickness of 80 μm is visually observed. confirmed.
<Evaluation criteria>
○: No cloudiness ×: Cloudiness

(Evaluation 6) Storage stability at low temperature The appearance when the polyisocyanate composition was stored at -10 ° C was observed.
<Evaluation criteria>
○: No cloudiness after storage for 1 week △: No cloudiness after storage for 3 days ×: Cloudiness after storage for 1 week ×: Cloudiness after storage for 3 days

[Reference Examples 1-9, Comparative Reference Examples 1-4]
Each evaluation of sclerosis | hardenability, compatibility, and the storage stability in low temperature was performed using the block polyisocyanate composition AM obtained by the synthesis examples 2-14. The obtained results are shown in Table 3.

(Synthesis Example 15) Polyisocyanate A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube and a dropping funnel was placed in a nitrogen atmosphere, charged with 1000 g of HDI, and the reactor temperature was 60 ° C. with stirring. Retained. Thereafter, 2.1 g of tetramethylammonium acetate (2-butanol 5.0 mass% solution) was added as an isocyanurate reaction catalyst to carry out the reaction. After 4 hours, the reaction end point was confirmed by measuring the refractive index of the reaction solution, and 0.2 g of phosphoric acid (85 mass% aqueous solution) was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin film distillation apparatus to obtain a polyisocyanate having an isocyanurate group. The obtained polyisocyanate had a viscosity at 25 ° C. of 2500 mPa · s and an NCO group content of 22.2% by mass.

(Reference Example 10) Blocked polyisocyanate composition N
A four-necked flask equipped with a stirrer, a thermometer, and a nitrogen blowing tube was put in a nitrogen atmosphere, 100 parts of the polyisocyanate obtained in Synthesis Example 15 and 41.7 parts of butyl acetate were charged, and diethyl malonate 53.3 was added. A mixture of 28.9 parts of ethyl acetoacetate and 0.8 parts of 28% sodium methylate solution was added at room temperature, and the reaction was continued at 80 ° C. for 2 hours. Thereafter, 74.6 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 3 hours while flowing nitrogen to obtain a block polyisocyanate composition N having a resin content of 60%. Table 4 shows the effective NCO group content and the molar ratio M of the obtained block polyisocyanate composition N.

Reference Example 11 Blocked polyisocyanate composition O
In the same apparatus as in Reference Example 10, 100 parts of the polyisocyanate obtained in Synthesis Example 15 and 42.3 parts of butyl acetate were charged, 71.1 parts of diethyl malonate, 14.5 parts of ethyl acetoacetate, 28% A mixture of 0.8 parts of sodium methylate solution was added at room temperature and the reaction was continued at 80 ° C. for 2 hours. Thereafter, 76.0 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 3 hours while flowing nitrogen. A block polyisocyanate composition O having a resin content of 60% was obtained. Table 4 shows the effective NCO group content and the molar ratio M of the obtained block polyisocyanate composition O.

(Reference Example 12) Blocked polyisocyanate composition P
In the same apparatus as in Reference Example 10, 100 parts of the polyisocyanate obtained in Synthesis Example 15 and 43.0 parts of butyl acetate were charged, 88.9 parts of diethyl malonate, 0.8 part of 28% sodium methylate solution Was added at room temperature and the reaction was continued at 80 ° C. for 2 hours. Thereafter, 75.3 parts of 1-butanol was added and stirred at 80 ° C. for 3 hours while flowing nitrogen. A block polyisocyanate composition P having a resin content of 60% was obtained. Table 4 shows the effective NCO group content and the molar ratio M of the obtained block polyisocyanate composition P.

(Reference Example 13) Blocked polyisocyanate composition Q
In the same apparatus as in Reference Example 10, 100 parts of the polyisocyanate obtained in Synthesis Example 15 and 42.3 parts of butyl acetate were charged, 71.1 parts of diethyl malonate, 14.5 parts of ethyl acetoacetate, 28% A mixture of 0.8 parts of sodium methylate solution was added at room temperature and the reaction was continued at 80 ° C. for 2 hours. Thereafter, 76.0 parts of 1-butanol was added and stirred for 1 hour at 80 ° C. while flowing nitrogen. A block polyisocyanate composition Q having a resin content of 60% was obtained. Table 4 shows the effective NCO group content and the molar ratio M of the obtained block polyisocyanate composition Q.

(Reference Example 14) Blocked polyisocyanate composition R
In the same apparatus as in Reference Example 10, 100 parts of the polyisocyanate obtained in Synthesis Example 15 and 42.3 parts of butyl acetate were charged, 94.0 parts of diisopropyl malonate, 7.2 parts of ethyl acetoacetate, 28% A mixture of 0.8 parts of sodium methylate solution was added at room temperature and the reaction was continued at 50 ° C. for 2 hours. Thereafter, 82.2 parts of isobutanol was added, and the mixture was stirred at 80 ° C. for 3 hours while flowing nitrogen. A block polyisocyanate composition R having a resin content of 60% was obtained. Table 4 shows the effective NCO group content and molar ratio M of the obtained block polyisocyanate composition R.

(Comparative Reference Example 5) Block polyisocyanate composition S
In the same apparatus as in Reference Example 10, 100 parts of the polyisocyanate obtained in Synthesis Example 15 and 42.3 parts of butyl acetate were charged, 94.0 parts of diisopropyl malonate, 7.2 parts of ethyl acetoacetate, 28% A mixture of 0.8 parts of sodium methylate solution was added at room temperature and the reaction was continued at 50 ° C. for 2 hours. Thereafter, 82.2 parts of isobutanol was added and stirred at 50 ° C. for 2 hours under a nitrogen atmosphere (no flow). A block polyisocyanate composition S having a resin content of 60% was obtained. Table 4 shows the effective NCO group content and the molar ratio M of the obtained block polyisocyanate composition S.

(Comparative Reference Example 6) Block polyisocyanate composition T
A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a dropping funnel was placed in a nitrogen atmosphere, and 100 parts of the polyisocyanate obtained in Synthesis Example 15 and 42.3 parts of butyl acetate were charged, and malonic acid was added. A mixture of 71.1 parts of diethyl, 14.5 parts of ethyl acetoacetate and 0.8 parts of 28% sodium methylate solution was added at room temperature, and the reaction was continued at 80 ° C. for 2 hours. Thereafter, 76.0 parts of 1-butanol was added and stirred at 80 ° C. for 1 hour under a nitrogen atmosphere (no flow). A block polyisocyanate composition T having a resin content of 60% was obtained. Table 4 shows the effective NCO group content and molar ratio M of the obtained block polyisocyanate composition T.

(Comparative Reference Example 7) Block polyisocyanate composition U
In the same apparatus as in Reference Example 10, 100 parts of the polyisocyanate obtained in Synthesis Example 15 and 49.1 parts of butyl acetate were charged, 120.0 parts of dibutyl malonate, and 0.8 parts of 28% sodium methylate solution. Was added at room temperature and the reaction was continued at 80 ° C. for 2 hours. Thereafter, 89.7 parts of 1-butanol was added. A block polyisocyanate composition U having a resin content of 60% was obtained. Table 4 shows the effective NCO group content and the molar ratio M of the obtained block polyisocyanate U.

(Evaluation 7) Curability Block polyisocyanate compositions N to U obtained in Reference Examples 10 to 14 and Comparative Reference Examples 5 to 7 and Setalx 1152 (acryl polyol, manufactured by Nuplex Resins, hydroxyl value 70.4 mgKOH / g ( Solid) and a solid content of 51% by mass were mixed so that NCO / OH = 1.0, and diluted with butyl acetate to a solid content of 50%. The obtained coating composition was applied to an PP applicator so as to have a resin film thickness of 80 μm. After drying at a temperature of 23 ° C. for 30 minutes and baking at 100 ° C. for 30 minutes, the coating film was peeled off from the plate. The residual film ratio (gel fraction) when immersed in acetone at 23 ° C. for 24 hours was measured, and the curability was evaluated according to the following evaluation criteria.
(Evaluation criteria)
○: Gel fraction is 90% by mass or more ×: Gel fraction is less than 90%

(Evaluation 8) Compatibility (Evaluation 7) The coating composition prepared by the same method as the curability was visually checked for transparency after the applicator was coated on the glass plate so that the resin film thickness was 80 μm. The compatibility was evaluated according to the following evaluation criteria.
(Evaluation criteria)
○: No cloudiness ×: Cloudiness

(Evaluation 9) Storage stability (Evaluation 7) Viscosity was measured by the same method as (Physical property 2) before and after storage of a coating composition prepared in the same manner as curable property at 50 ° C. for 1 week. The storage stability was evaluated according to the evaluation criteria.
(Evaluation criteria)
○: Less than 10 times the initial value Δ: 10 times to less than 30 times the initial value ×: 30 times or more the initial value

  For the block polyisocyanate compositions N to U obtained in Reference Examples 10 to 14 and Comparative Reference Examples 5 to 7, (Evaluation 7) Curability, (Evaluation 8) Compatibility, (Evaluation 9) Storage stability The results of each evaluation are shown in Table 4.

  This application includes a Japanese patent application (Japanese Patent Application No. 2015-180016) filed with the Japan Patent Office on September 11, 2015, and a Japanese patent application filed with the Japan Patent Office on September 11, 2015 ( (Japanese Patent Application No. 2015-180021), Japanese Patent Application filed with the Japan Patent Office on October 22, 2015 (Japanese Patent Application No. 2015-207937), and Japanese Patent Application with the Japan Patent Office on November 18, 2015 Japanese patent application (Japanese Patent Application No. 2015-225990), the contents of which are incorporated herein by reference.

  The block polyisocyanate composition according to the present invention can be suitably used as a one-component coating composition excellent in low-temperature curability, adhesion to the upper layer, and compatibility with polyol.

  The block polyisocyanate composition according to the present invention is excellent in low-temperature curability, compatibility, and storage stability at low temperatures because the specific bonding group in the blocking agent is contained in a specific ratio. Therefore, it exhibits excellent performance as a paint, adhesive, pressure-sensitive adhesive, ink, sealing agent, casting agent, sealant, surface modifier, coating agent and the like. Moreover, since the specific terminal alkyl group produced | generated with the blocking agent is contained in a specific ratio, it is excellent in low-temperature curability, storage stability, and compatibility. Therefore, it exhibits excellent performance as a paint, adhesive, pressure-sensitive adhesive, ink, sealing agent, casting agent, sealant, surface modifier, coating agent and the like.

Claims (11)

A block polyisocyanate obtained from a polyisocyanate derived from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, and a blocking agent,
The blocking agent includes at least one selected from the group consisting of a malonic acid diester compound represented by the following formula (I) and a β ketoester compound represented by the following formula (II):
The molar ratio of the sum of the keto structure shown in the following formula (III) and the sum of the keto structure shown in the following formula (IV) to the sum of the enol structure shown in the following formula (V) and the enol structure shown in the following formula (VI). Is a block polyisocyanate composition having a ratio of 75/25 to 97/3.
(Formula (in I) ~ (VI), R ₁ and R ₂ are each independently an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a phenyl group, a benzyl group. Plurality of R ₁ or R ₂ is independent of each other.)   The block polyisocyanate composition according to claim 1, wherein a molar ratio of the sum of the keto body structures to the sum of the enol body structures is 75/25 or more and 96/4 or less. The blocking agent includes the malonic acid diester compound,
The block polyisocyanate according to claim 1 or 2, wherein the ratio of the methanetetracarbonyl structure represented by the following formula (VII) to the total amount of the isocyanate-malonic acid diester bond structure is 0.5 mol% or more and 10 mol% or less. Composition.
(In the formula (VII), R ₁ and R ₂ each independently represents an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a phenyl group, or a benzyl group.) Further comprising a monohydric alcohol compound,
When the number of moles of the following three bonds contained in the block polyisocyanate is (a) to (c), respectively, (a) / ((a) + (b) + (c)) = 0.020 The block polyisocyanate composition according to any one of claims 1 to 3, which is not less than 0.50.
(A) Urethane bond between isocyanate group and monohydric alcohol compound (b) Bond between isocyanate group and malonic acid diester compound (c) Bond between isocyanate group and β-ketoester compound Further comprising a monohydric alcohol compound,
The blocked polyisocyanate composition has a structure in which an isocyanate group is blocked with an enol body of the malonic acid diester compound, and includes at least a blocked isocyanate structure represented by the formula (V),
In the block polyisocyanate composition, the molar ratio of the block isocyanate structure in which at least one of R ₁ and R ₂ in the formula (V) represents an alkyl group having 4 to 8 carbon atoms with respect to the total amount of the blocked isocyanate structure is The block polyisocyanate composition according to any one of claims 1 to 4, which is 0.50 or more and less than 0.95.   The block polyisocyanate composition according to any one of claims 1 to 5, wherein the blocking agent comprises the malonic acid diester compound and the β keto ester compound.   The block polyisocyanate composition according to claim 6, wherein a molar ratio of the malonic acid diester compound to the β ketoester compound exceeds 1.0. The malonic acid diester compound is diethyl malonate, and
The block polyisocyanate composition according to any one of claims 1 to 7, wherein the β-ketoester compound is ethyl acetoacetate.   The one-pack type coating composition containing the block polyisocyanate composition as described in any one of Claims 1-8, and a polyol.   A coating film formed from the one-component coating composition according to claim 9.   A coated article coated with the one-component coating composition according to claim 9.