JP6849353B2 - Block polyisocyanate compositions, one-component coating compositions, coatings, and coated articles - Google Patents

Description

The present invention relates to block polyisocyanate compositions, one-component coating compositions, coatings, and coated articles.

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

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

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

Examples of the blocked polyisocyanate composition capable of further lowering the baking temperature include a blocked polyisocyanate composition containing malonic acid diester as a blocking agent (see, for example, Patent Document 3), diethyl malonate and ethyl acetoacetate. (See, for example, Patent Documents 4 and 5) and the like have been proposed.

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

However, the blocked polyisocyanate composition formed by using the conventional blocking agent generally requires a high baking temperature of 140 ° C. or higher, so that the energy cost becomes very high. Further, 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 as described in Patent Documents 1 and 2, a baking temperature of about 120 ° C. is required, and further reduction of the baking temperature is desired.

Further, in applications such as painting of new automobiles, a coating film such as a clear layer may be further laminated on a coating film layer using a conventional block polyisocyanate composition. As the 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 lower and having good adhesion when laminated is desired.

On the other hand, the blocked 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 blocked polyisocyanate compositions were used. There is a further problem in the adhesion when the coating film is further laminated on the coating film layer. Further, a coating film such as a clear layer may be further laminated on the coating film layer using these blocked polyisocyanate compositions, and the blocked polyisocyanate composition having good adhesion when laminated, and the blocked polyisocyanate composition thereof. The one-component coating composition used is desired. On the other hand, depending on the case where these blocked polyisocyanate compositions are used, the compatibility with some polyols may be insufficient.

Therefore, the present invention provides a blocked polyisocyanate composition that maintains low-temperature curability, has excellent adhesion to the upper coating film when the coating film is laminated, and has excellent compatibility with the polyol. With the goal.

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

（前記式（Ｉ）〜（ＶＩ）中、Ｒ₁及びＲ₂は、各々独立に、炭素数１〜８個のアルキル基、シクロアルキル基、フェニル基、ベンジル基を示す。複数のＲ₁又はＲ₂は、各々独立している。）
［２］
前記エノール体構造の合計に対する前記ケト体構造の合計のモル比が、７５／２５以上９６／４以下である、［１］に記載のブロックポリイソシアネート組成物。
［３］
前記ブロック剤は、前記マロン酸ジエステル化合物を含み、
イソシアネート−マロン酸ジエステル結合構造の総量に対する下記式（ＶＩＩ）で示されるメタンテトラカルボニル構造の比率が、０．５モル％以上１０モル％以下である、［１］又は［２］に記載のブロックポリイソシアネート組成物。

（前記式（ＶＩＩ）中、Ｒ₁及びＲ₂は、各々独立に、炭素数１〜８個のアルキル基、シクロアルキル基、フェニル基、ベンジル基を示す。）
［４］
１価アルコール化合物をさらに含み、
前記ブロックポリイソシアネートに含まれる以下の３つの結合のモル数を各々（ａ）〜（ｃ）としたときに、（ａ）／（（ａ）＋（ｂ）＋（ｃ））＝０．００２０以上０．５０未満である、［１］〜［３］のいずれかに記載のブロックポリイソシアネート組成物。
（ａ）イソシアネート基と１価アルコール化合物とのウレタン結合
（ｂ）イソシアネート基とマロン酸ジエステル化合物との結合
（ｃ）イソシアネート基とβケトエステル化合物との結合
［５］
１価アルコール化合物をさらに含み、
前記ブロックポリイソシアネート組成物は、イソシアネート基が前記マロン酸ジエステル化合物のエノール体でブロックされた構造であり、かつ前記式（Ｖ）で表される、ブロックイソシアネート構造を少なくとも含み、
前記ブロックポリイソシアネート組成物において、前記ブロックイソシアネート構造の総量に対する、前記式（Ｖ）におけるＲ₁及びＲ₂の少なくとも一方が炭素数４以上８以下のアルキル基を示す前記ブロックイソシアネート構造のモル比が、０．５０以上０．９５未満である、［１］〜［４］のいずれかに記載のブロックポリイソシアネート組成物。
［６］
前記ブロック剤は、前記マロン酸ジエステル化合物及び前記βケトエステル化合物を含む、［１］〜［５］のいずれかに記載のブロックポリイソシアネート組成物。
［７］
前記βケトエステル化合物に対する前記マロン酸ジエステル化合物のモル比が、１．０を超える、［６］に記載のブロックポリイソシアネート組成物。
［８］
前記マロン酸ジエステル化合物は、マロン酸ジエチルであり、かつ、
前記βケトエステル化合物は、アセト酢酸エチルである、［１］〜［７］のいずれかに記載のブロックポリイソシアネート組成物。
［９］
［１］〜［８］のいずれかに記載のブロックポリイソシアネート組成物と、ポリオールと、を含む一液型コーティング組成物。
［１０］
［９］に記載の一液型コーティング組成物により形成された塗膜。
［１１］
［９］に記載の一液型コーティング組成物により塗装された塗装物品。 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, a blocking agent, and the like.
The blocking agent contains at least one selected from the group consisting of the malonic acid diester compound represented by the following formula (I) and the β-ketoester compound represented by the following formula (II).
The molar ratio of the total molar ratio of the keto-enol structure represented by the following formula (III) and the keto-enol structure represented by the following formula (IV) to the total of the enol body structure represented by the following formula (V) and the enol body structure represented by the following formula (VI). However, the blocked polyisocyanate composition is 75/25 or more and 97/3 or less.

(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 blocked polyisocyanate composition according to [1], wherein the total molar ratio of the keto-enol structure to the enol structure is 75/25 or more and 96/4 or less.
[3]
The blocking agent contains the malonic acid diester compound and contains.
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 above formula (VII), R ₁ and R ₂ each independently represent an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a phenyl group, and a benzyl group.)
[4]
Further containing a monohydric alcohol compound,
When the number of moles of the following three bonds contained in the blocked polyisocyanate is (a) to (c), (a) / ((a) + (b) + (c)) = 0.0020. The blocked polyisocyanate composition according to any one of [1] to [3], which is more than 0.50 and 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 containing a monohydric alcohol compound,
The blocked polyisocyanate composition has a structure in which an isocyanate group is blocked by an enol compound of the malonic acid diester compound, and contains at least a blocked isocyanate structure represented by the formula (V).
In the blocked polyisocyanate composition, the molar ratio of the blocked isocyanate structure to which the total amount of the blocked isocyanate structure is such that _{at least one of R 1} and R ₂ in the formula (V) exhibits an alkyl group having 4 or more and 8 or less carbon atoms. , 0.50 or more and less than 0.95, the blocked polyisocyanate composition according to any one of [1] to [4].
[6]
The blocked polyisocyanate composition according to any one of [1] to [5], wherein the blocking agent contains the malonic acid diester compound and the β-ketoester compound.
[7]
The blocked polyisocyanate composition according to [6], wherein the molar ratio of the malonic acid diester compound to the β-ketoester compound exceeds 1.0.
[8]
The malonic acid diester compound is diethyl malonate and
The blocked polyisocyanate composition according to any one of [1] to [7], wherein the β-ketoester compound is ethyl acetoacetate.
[9]
A one-component coating composition containing the block polyisocyanate composition according to any one of [1] to [8] and a polyol.
[10]
A coating film formed by the one-component coating composition according to [9].
[11]
A painted article coated with the one-component coating composition according to [9].

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

Hereinafter, embodiments 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 can be variously modified and implemented within the scope of the gist thereof.

（上記式（Ｉ）〜（ＶＩ）中、Ｒ₁及びＲ₂は、各々独立に、炭素数１〜８個のアルキル基、シクロアルキル基、フェニル基、ベンジル基を示す。複数のＲ₁又はＲ₂は、各々独立している。） [Block polyisocyanate composition]
The blocked polyisocyanate composition of the present embodiment contains a blocked polyisocyanate obtained from a polyisocyanate derived from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, a blocking agent, and the like. .. Further, the blocking agent contains at least one selected from the group consisting of the malonic acid diester compound represented by the following formula (I) and the β-ketoester compound represented by the following formula (II). Further, the blocked polyisocyanate composition has a keto-enol structure represented by the following formula (III) and a keto-enol structure represented by the following formula (IV) with respect to the sum of the enol body structure represented by the following formula (V) and the enol body structure represented by the following formula (VI). The molar ratio of the keto body structure shown in 1 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 blocked polyisocyanate composition of the present embodiment includes at least one of the keto body structure represented by the above formula (III) and the keto body structure represented by the above formula (IV), the enol body structure represented by the above formula (V), and the above. It contains at least one of the enol body structures represented by the formula (VI) 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, and a benzyl group. R ₁ and R ₂ may be the same or different. Further, when an alkyl group or a cycloalkyl group having 8 or less carbon atoms is exhibited, the decrease in the effective NCO content may be suppressed and the decrease in compatibility with the main agent or the like when used as a coating material may be suppressed. preferable. Among these, R ₁ and R ₂ preferably independently exhibit an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and further preferably. Indicates 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. Is.

The molar ratio of the keto-enol structure represented by the formula (III) and the keto-enol structure represented by the formula (IV) to the total of the enol structure represented by the formula (V) and the enol structure represented by the formula (VI) is It is 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. The molar ratio is 87/13 or more and 93/7 or less, more preferably. When the molar ratio is 75/25 or more, good compatibility with the polyol can be obtained. Further, when the molar ratio is 97/3 or less, the coating film layer using the block polyisocyanate composition of the present embodiment can exhibit adhesion to the further coated upper layer coating film. The molar ratio can be measured by the method described in Examples described later.

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

The blocked polyisocyanate composition of the present embodiment preferably has a methanetetracarbonyl 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, and a benzyl group. R ₁ and R ₂ may be the same or different. Since R ₁ and R ₂ each independently have a methanetetracarbonyl structure showing an alkyl group, a phenyl group, and a benzyl group having 8 or less carbon atoms, the decrease in the effective NCO content is suppressed and the coating material is used. It tends to be possible to improve the compatibility with the main agent and the like, which is more preferable. Among these, R ₁ and R ₂ preferably have a methanetetracarbonyl structure each independently exhibiting an alkyl group having 1 to 8 carbon atoms, and more preferably a methanetetracarbonyl exhibiting an alkyl group having 1 to 4 carbon atoms. It has a structure, more preferably a methanetetracarbonyl structure showing an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group.

In the blocked polyisocyanate composition, the ratio of the methanetetracarbonyl 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. Is. The lower limit of the ratio is more preferably 0.7 mol%, further preferably 1.0 mol%, even more preferably 1.5 mol%, still more preferably 2.0 mol. %. The upper limit of the ratio is more preferably 8.0 mol%, further preferably 6.0 mol%, even more preferably 5.0 mol%, still more preferably 4.0 mol%. %. When the ratio is 0.5 mol% or more, the coating film layer using the block polyisocyanate composition of the present embodiment can further exhibit adhesion to the coated upper layer coating film, and also When the ratio is 10 mol% or less, the compatibility with the polyol tends to be maintained. The ratio can be measured by the method described in Examples described 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 and enol form) and a methanetetracarbonyl structure.

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

The blocked polyisocyanate composition of the present embodiment preferably further contains a monohydric alcohol compound described later. Further, in the block polyisocyanate composition, the molar ratio of the monohydric alcohol compound to the block polyisocyanate group of the block polyisocyanate composition is more preferably 0.2 or more and 10 or less.

The monohydric alcohol compound is not particularly limited, and examples thereof include monohydric alcohol compounds such as aliphatic, alicyclic, and aromatic compounds, and among them, an aliphatic monohydric alcohol compound is preferable. The aliphatic monohydric alcohol compound is not particularly limited, but is more preferably a monohydric alcohol compound having 1 to 20 carbon atoms. The monohydric alcohol compound having 1 to 20 carbon atoms is not particularly limited, and for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, t-butanol, 2-ethyl-1-propanol, and the like. 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 blocked polyisocyanate composition is more preferably 0.2 or more and 10 or less. The lower limit of the molar ratio is even more preferably 0.4, even more preferably 0.7, and even more preferably 1.0. The upper limit of the molar ratio is even more preferably 7.0, even more preferably 5.0, and even more preferably 3.0. The effective NCO content rate tends to be assured that the molar ratio is 0.2 or more and the storage stability of the one-component coating composition can be ensured, and that the molar ratio is 10 or less. There is a tendency that the decrease in the amount of

The effective isocyanate group content of the blocked polyisocyanate (hereinafter referred to as the effective NCO group content) is the content of isocyanate groups potentially present with respect to the total mass of the blocked polyisocyanate.

The effective NCO content of the blocked polyisocyanate composition (hereinafter referred to as "effective NCO group content") is not particularly limited, but is 3.0% by mass or more with respect to the total amount of solids (100% by mass) 22. It is preferably 50% by mass or less, more preferably 5.0% by mass or more and 20% by mass or less, further preferably 8.0% by mass or more and 20% by mass or less, and 8.0% by mass or more 18 It is even more preferably 10% by mass or more and 15% by 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 amount of solids (100% by mass), both low temperature stability and storage stability tend to be compatible. Further, when the effective NCO content is 8.0% by mass or more with respect to the total amount of solids (100% by mass), the crosslink density after baking tends to be well maintained, and the effective NCO content is 20. When the mass is less than%, the smoothness of the coating film after baking tends to be ensured. For example, in order to obtain a blocked 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 amount of solids (100% by mass), for example, the NCO content is 15% by mass. Polyisocyanate of% or more and 25% by mass or less may be used as a raw material. The effective NCO content can be measured by the method described in Examples described later.

Further, the effective NCO group content can be obtained from the charged amount of polyisocyanate, the NCO group content, and the charged amount of the blocking agent.

The solid content concentration of the blocked 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 volatilization amount at the time of baking tends to be reduced, and when the solid content concentration is 80% by mass or less, the workability when blending the blocked polyisocyanate composition is good. Tends to be able to. 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 have the solid content concentration. The solid content concentration can be measured by the method described in Examples described later.

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

By taking the above-mentioned form, the blocked polyisocyanate composition of the present embodiment tends to be able to provide a blocked polyisocyanate composition that is more compatible with the main agent and has storage stability at a low temperature.

式（Ｖ）中、Ｒ₁及びＲ₂は、各々独立に炭素数１〜８のアルキル基を示す。 The blocked polyisocyanate composition of the present embodiment further contains a monohydric alcohol compound, and the blocked polyisocyanate composition has a structure in which the isocyanate group is blocked by the enol form of the malonic acid diester compound, and the following formula ( _{In the blocked polyisocyanate composition, at least one of R 1} and R ₂ in the formula (V) has 4 or more and 8 or less carbon atoms with respect to the total amount of the blocked isocyanate structure, which contains at least the blocked isocyanate structure represented by V). It is more preferable that the molar ratio of the blocked isocyanate structure showing an alkyl group is 0.50 or more and less than 0.95.

In formula (V), R ₁ and R ₂ each independently represent an alkyl group having 1 to 8 carbon atoms.

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

The blocked polyisocyanate composition of the present embodiment has a structure in which the isocyanate group contained in the polyisocyanate described later is blocked by an enol form of malonic acid diester, and at least contains a blocked isocyanate structure represented by the formula (V). Is more preferable. In order to obtain a blocked polyisocyanate composition containing such a blocked isocyanate structure, for example, the polyisocyanate described later may be blocked with a malonic acid diester and then further reacted with a monohydric alcohol compound. Further, in such a blocked polyisocyanate, a part of the isocyanate group contained in the polyisocyanate is blocked by a blocking agent containing the malonic acid diester. That is, the blocked isocyanate structure may include a structure that remains blocked by the malonic acid diester, which will be described later, and a structure that is further reacted with the monohydric alcohol compound.

Further, it is preferable that the blocked polyisocyanate composition contains _{a blocked isocyanate structure in which at least one of R 1} and R ₂ in the formula (V) exhibits an ethyl group from the viewpoint of low temperature curability. _{In order to obtain a blocked polyisocyanate composition containing a blocked isocyanate structure in which at least one of R 1} and R ₂ in the formula (V) exhibits an ethyl group, for example, diethyl malonate may be used as the malonic acid diester described later.

In the blocked polyisocyanate composition, _{the molar ratio of the blocked isocyanate structure in which at least one of R 1} and R ₂ in the formula (V) exhibits an alkyl group having 4 or more and 8 or less carbon atoms is based on the total amount of the blocked isocyanate structure. It is preferably 0.50 or more and less than 0.95, more preferably 0.60 or more and 0.93 or less, still more preferably 0.65 or more and 0.91 or less, and even more preferably 0.70 or more and 0. It is .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 the present embodiment is derived from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

The polyisocyanate of the present embodiment is obtained from one or more kinds of diisocyanates selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and is a multimer consisting of a dimer 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 not having an aromatic hydrocarbon. Further, in the present embodiment, the "aliphatic diisocyanate" also refers to a compound having a chain aliphatic hydrocarbon and no aromatic hydrocarbon when the isocyanate group is removed from the molecule.

The aliphatic diisocyanate is not particularly limited, but preferably has 4.0 or more and 30 or less carbon atoms, for example, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (hereinafter, abbreviated as “HDI”), butane diisocyanate. , Pentandiisocyanate, trimethylhexamethylene diisocyanate, 2,2,4-trimethyl-1,6-diisocyanatohexane, lysine diisocyanate. It is more preferable to use such an aliphatic diisocyanate because the obtained polyisocyanate has a low viscosity. Among them, HDI is more preferable because of its ease of industrial availability. The aliphatic diisocyanate may be used alone or in combination of two or more.

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

The alicyclic diisocyanate is not particularly limited, but preferably has 8.0 or more and 30 or less carbon atoms, for example, isophorone diisocyanate (hereinafter abbreviated as “IPDI”), 1,3-bis (isocyanatomethyl). Examples thereof include −cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, norbornene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and 1,4-cyclohexanediisocyanate. Among them, IPDI is more preferable because of its weather resistance and easy industrial availability. The alicyclic diisocyanate may be used alone or in combination of two or more.

Among the above 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.

The 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. Examples thereof include 2 to 20-mer oligomers of diisocyanate produced by forming a bond, an oxadiazine trione bond, or the like. The polyisocyanate having a biuret bond is, for example, a so-called biuret agent such as water, t-butanol, urea and diisocyanate, and the molar ratio of the biuret agent to the isocyanate group of the diisocyanate is about 1/2 to about 1/100. After the reaction, it is obtained by removing and purifying unreacted diisocyanate. The polyisocyanate having an isocyanurate bond is obtained by, for example, performing a cyclic triquantification reaction with a catalyst or the like, stopping the reaction when the conversion rate reaches about 5 to about 80% by mass, and removing and purifying the unreacted diisocyanate. .. At this time, 1-hexavalent alcohol compounds such as 1,3-butanediol and trimethylolpropane can be used in combination.

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

When the catalyst may adversely affect the physical characteristics 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, but for example, inorganic acids such as hydrochloric acid, phosphite, and phosphoric acid; methanesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid methyl ester, and ethyl p-toluenesulfonate. Sulfonic acid such as ester or a derivative 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 thereof 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 has, for example, a 2- to 6-valent alcohol compound such as trimethylolpropane and diisocyanate, 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 1/1. After reacting with 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 amount of solids (100% by mass). It is preferable, more preferably 13% by mass or more and 24% by mass or less, still more preferably 15% by mass or more and 25% by mass or less, still more preferably 17% by mass or more and 24% by mass or less, and even more preferably 17 It is mass% or more and 22 mass% or less. When the isocyanate content is 15% by mass or more, the crosslink density of the coating film after baking is secured, and good curability tends to be obtained. When the isocyanate content is 25% by mass or less, the coating after baking tends to be obtained. It tends to ensure the flexibility of the membrane. 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 of solids (100% by mass), a 2 to 6-valent alcohol compound is appropriately used at an appropriate conversion rate. Examples include the method of use. The NCO content can be measured by the method described in Examples described later.

The NCO group content of the polyisocyanate can also be determined, for example, by reacting the isocyanate group of the polyisocyanate with an excess amine (dibutylamine or the like) and back-dripping 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, more preferably 100 mPa · s or more and 100,000 mPa · s or less, and further preferably 100,000 mPa · s or less at 25 ° C. 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, the crosslinkability at the time of baking tends to be well secured, and when the viscosity is 2,000,000 mPa · s or less, the smoothness of the coating film after baking is good. Tends to be able to maintain. Further, when the viscosity is in such a range, sufficient curability and a good coating film appearance tend to be obtained. 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 2-hexavalent alcohol compound at an appropriate conversion rate and the like can be mentioned. The viscosity can be measured by the method described in Examples described 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 satisfactorily secured, and when the number average molecular weight is 1500 or less, the crosslink density of the coating film after baking tends to be satisfactorily secured. 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 isocyanurate-forming reaction may be 5.0% by mass to 80% by 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 further. It is preferably 0.5% by mass or less. When the residual HDI concentration is 2.0% by mass or less, the risk during handling can be further reduced, and the curability of the coating composition tends to be further improved. In order to obtain a polyisocyanate having a residual HDI concentration of 2.0% by mass or less, it may be removed by a thin film evaporation feeling, extraction 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 one or more polyisocyanates 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 used, low temperature curability tends to be exhibited. On the other hand, when the average number of isocyanate groups is 20 or less, it tends to be possible to suppress the viscosity from becoming too high and obtain a polyisocyanate having good workability.

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

The polyisocyanate is not particularly limited, but for example, a biuret group (bond), a urea group (bond), an isocyanurate group (bond), a uretdione group (bond), a urethane group (bond), an allophanate group (bond), and an oxadia. Examples thereof include polyisocyanates having one 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, but for example, a so-called biuret agent such as water, t-butanol or urea and diisocyanate have a molar ratio of (biuret agent) / (isocyanate group of diisocyanate) of about. It can be obtained by removing the unreacted diisocyanate after reacting under the condition of 1/2 to about 1/100. 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 may be formed from, for example, 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 low. As a result, the obtained polyisocyanate tends to be less likely to aggregate.

The polyisocyanate having an isocyanurate bond is not particularly limited, but for example, a diisocyanate isocyanurate-forming reaction is carried out with a catalyst or the like, and the reaction is stopped when the conversion rate reaches about 5 to about 80% by mass, and the reaction is not reacted. It can be obtained by removing the diisocyanate of. The isocyanurate-forming reaction catalyst used at this time is not particularly limited, but specifically, a basic one is generally preferable, and a tetraalkylammonium such as tetramethylammonium or tetraethylammonium is hydrooxide or acetate. , Organic weak salts such as capric acid; Hydrooxides of hydroxyalkylammoniums such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, triethylhydroxyethylammonium, or organic weak acid salts such as acetic acid and capric acid; acetic acid Alkali metal salts of tin, zinc, lead and the like of alkylcarboxylic acids such as caproic acid, octyl acid and myristic acid; metal alcoholates such as sodium and potassium; aminosilyl group-containing compounds such as hexamethyldisilazane; Mannig bases; Combination of tertiary amines and epoxy compounds; for example, phosphorus compounds such as tributylphosphine. The amount of these catalysts used is preferably selected from the range of 10 ppm to 1% with respect to the mass of the raw material diisocyanate and the alcohol polyol added as needed. When terminating the isocyanurate-forming reaction, for example, a method of neutralizing the isocyanurate-forming reaction catalyst and a method of inactivating by addition of an acidic substance such as phosphoric acid or an acidic phosphoric acid ester, thermal decomposition, or chemical decomposition are available. Can be mentioned.

The polyisocyanate having a uretdione bond is not particularly limited, but can be obtained, for example, by using a diisocyanate and a uretdione reaction catalyst. The uretdione reaction catalyst is not particularly limited, but specifically, trialkylphosphine such as tri-n-butylphosphine and tri-n-octylphosphine, and tris (dialkylamino) such as tris- (dimethylamino) -phosphine. ) Phosphine, a third phosphine such as cycloalkylphosphine such as cyclohexyl-di-n-hexylphosphine can be mentioned. These compounds can also be allophanation reaction catalysts. In addition, many of these compounds also promote the isocyanurate-forming reaction at the same time to produce isocyanurate group-containing polyisocyanates such as isocyanurate trimers in addition to uretdione group-containing polyisocyanates such as uretdione dimers. Can be done. Further, the uretdione dimer can also be obtained by heating without using a uretdione 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, but for example, a compound having a hydroxyl group and a diisocyanate are reacted at an equivalent ratio of a hydroxyl group to an isocyanate group (hydroxyl group / isocyanate group) at about 1/2 to about 1/100. After that, 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 even more preferably 60 to 120 ° C. in terms of reaction rate, suppression of side reactions, and prevention of coloring. The reaction time is preferably 10 minutes to 24 hours, more preferably 15 minutes to 15 hours, and even more preferably 20 minutes to 10 hours in the same respect as the reaction temperature. The urethanization reaction can be carried out 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. The allophanation reaction catalyst is not particularly limited, and examples thereof include alkyl carboxylates such as tin, lead, zinc, bismuth, zirconium, and zirconyl, and specific examples thereof include tin 2-ethylhexanoate and dibutyltin dilaurate. Organozinc compounds such as lead 2-ethylhexanoate; organozinc compounds such as zinc 2-ethylhexanoate; organic bismuth compounds such as bismuth 2-ethylhexanoate; Organic zirconium compounds; Examples thereof include organic zirconyl compounds such as zirconyl 2-ethylhexanoate, and two or more of these can be used in combination. Further, the above-mentioned isocyanurate-forming reaction catalyst can also be used as an allophanate-forming reaction catalyst. When an allophanate reaction is carried out using an isocyanurate-forming reaction catalyst, an isocyanurate group-containing polyisocyanate can also be produced. It is economically preferable to use an isocyanurate-forming reaction catalyst as the allophanate-forming reaction catalyst and to carry out the allophanate-forming reaction and the isocyanurate-forming reaction at the same time, which is more preferable in terms of production.

The molar ratio of the 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 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. When it is 1/1000 or more, the average number of allophanate groups tends to increase, and the produced blocked polyisocyanate composition tends to have a lower viscosity, which is preferable. Further, when it is set to 1/10 or less, the average number of isocyanate groups tends to increase and the curability is excellent, which is preferable.

The polyisocyanate having an iminooxadiazinedione bond is not particularly limited, but can be obtained by using, for example, diisocyanate and a specific catalyst. A technique relating 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.

上記式（Ｉ）及び式（ＩＩ）中、Ｒ₁及びＲ₂は、各々独立に、炭素数１〜８のアルキル基、シクロアルキル基、フェニル基、ベンジル基を示す。Ｒ₁及びＲ₂は、同一であっても、異なっていても構わないが、入手の容易さから、同一であることが好ましい。Ｒ₁及びＲ₂が炭素数８以下のアルキル基又はシクロアルキル基を示すものであると、有効ＮＣＯ含有率の低下を抑制すると共に、塗料としたときの主剤等との相溶性の悪化を抑制することができる傾向にある。これらの中でも、炭素数１〜８のアルキル基を示すものであることが好ましく、より好ましくは炭素数１〜４のアルキル基のメチル基、エチル基、ｎ−プロピル基、イソプロピル基、又はｎ−ブチル基を示すものであり、よりさらに好ましくはメチル基又はエチル基を示すものであり、さらにより好ましくはエチル基を示すものである。ここで有効ＮＣＯ含有率とは、ブロックポリイソシアネート組成物の総量（１００質量％）に対して、潜在的に存在するイソシアネート含有量（質量％）である。 <Blocking agent>
In the blocked polyisocyanate composition of the present embodiment, the blocking agent is 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 ketoester compounds (hereinafter, also simply referred to as “β-ketoester compounds”), and more preferably contains both malonic acid diester compounds and β-ketoester compounds.

In the above formulas (I) and (II), R ₁ and R ₂ independently represent an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a phenyl group, and a benzyl group, respectively. R ₁ and R ₂ may be the same or different, but are preferably the same because of their availability. When R ₁ and R ₂ represent an alkyl group or a cycloalkyl group having 8 or less carbon atoms, the decrease in the effective NCO content is suppressed and the deterioration of compatibility with the main agent or the like when used as a paint is suppressed. Tend to be able to. Among these, those showing an alkyl group having 1 to 8 carbon atoms are preferable, and more preferably, an alkyl group having 1 to 4 carbon atoms has a methyl group, an ethyl group, an n-propyl group, an isopropyl group, or an n-. It shows 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 (% by mass) that is potentially present with respect to the total amount (100% by mass) of the blocked polyisocyanate composition.

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

（式（１）中、Ｒはポリイソシアネート残基、Ｒ₁及びＲ₂はアルキル基、または、アルキルオキシ基より選ばれる少なくとも１種を示す。Ｒ₁及びＲ₂は同じ構造でも異なっていてもよい） As the blocking agent, at least one active methylene compound selected from the group consisting of malonic acid diester compounds and β-ketoester compounds is used. When the isocyanate group is blocked by these active methylene compounds, the blocked isocyanate group has an amide structure as shown in the following general formula (1).

(In the 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 have the same structure or different. Good)

Specific examples of the malonic acid diester compound are not particularly limited, but for example, dimethyl malonic acid, diethyl malonic acid, din-propyl malonic acid, diisopropyl malonic acid, din-butyl malonic acid, diisobutyl malonic acid, and diisobutyl malonic acid. Examples thereof include t-butyl, methyl malonic acid t-butyl ester, din-hexyl malonic acid, di2-ethylhexyl malonic acid, diphenyl malonic acid, and dibenzyl malonic acid. Among them, dimethyl malonate, diethyl malonate, di-propyl malonate, diisopropyl malonate, di-butyl malonate, diisobutyl malonate, dit-butyl malate, methyl t-butyl ester malonic acid, malonic acid. Din-hexyl and di2-ethylhexyl malonate are preferred. More preferably, it is dimethyl malonate, diethyl malonate, di-propyl malonate, diisopropyl malonate, and di-butyl malonate, more preferably dimethyl malonate, and diethyl malonate, and even more preferably. Diethyl malonate. The malonic acid diesters shown above can be used alone or in combination of two or more.

In terms of low temperature curability, preferably 50 equivalent% or more, more preferably 60 equivalent% or more, still more preferably 80 equivalent% or more of the isocyanate groups contained in the polyisocyanate are blocked by the malonic acid diester.

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

Examples of the β-ketoester compound include isopropyl acetate, n-propyl acetoacetic acid, t-butyl acetoacetic acid, n-butyl acetoacetic acid, and phenyl acetate.

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

The β-ketoester compound is preferably used in an amount of 50 equivalent% or less with respect to the isocyanate group of the polyisocyanate from the viewpoint of low temperature curability and suppression of yellowing. It is more preferably 40 equivalents or less, still more preferably 30 equivalents or less, and even more preferably 20 equivalents or less.

The above-mentioned malonic acid diester compound is preferably diethyl malonate, and the above-mentioned β-ketoester compound is preferably an acetoacetic acid ester compound from the viewpoint of more reliably exerting the desired action and effect 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 low temperature tends to be suppressed.

Further, since the β-ketoester compound tends to have a higher ratio of the enol body structure than the malonic acid diester compound, when the malonic acid diester compound and the β-keto ester compound are used in combination, the ratio of both blocking agents may be adjusted. , It is possible to adjust the molar ratio of keto-enol structure to enol structure.

The blocking agent of the present embodiment may further contain a blocking agent other than the above-mentioned malonic acid diester compound and β-ketoester compound (hereinafter, also referred to as “other blocking agent”). Specific examples of the other blocking agent are not particularly limited, but for example, a compound having one active hydrogen in the molecule is preferable. The compound having one active hydrogen in the molecule is not particularly limited, and for example, active methylene-based, mercaptan-based, acid amide-based, acid-imide-based, imidazole-based, and urea-based compounds other than malonic acid diester compounds and β-ketoester compounds. , Oxime-based, amine-based, imide-based, and pyrazole-based compounds.

In addition, examples of other blocking agents include alcohol-based, alkylphenol-based, and phenol-based compounds.

As more specific other blocking agents, (1) active oxime type other than malonic acid diester compound and β-ketoester compound; β-ketoester compound such as methyl isobutanoyl acetate and ethyl isobutanoyl acetate, acetylacetone and the like, (2) mercaptan type; butyl Mercaptan, dodecyl mercaptan, etc., (3) acid amides; acetanilide, acetate, ε-caprolactam, δ-valerolactam, γ-butyrolactam, etc., (4) acidimides; succinate imide, maleate imide, etc., (5) ) Imidazole-based; imidazole, 2-methylimidazole, etc., (6) urea-based; urea, thiourea, ethylene urea, etc., (7) oxime-based; formaldehyde, acetoaldoxime, acetooxime, methylethylketooxime (hereinafter, MEKO) (Abbreviated as), cyclohexanone oxime, etc. (8) Amine-based; diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine, diisobutylamine, di (2-butylamine), di (t-butyl) amine , Dicyclohexylamine, Nt-butylcyclohexylamine, 2-methylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, etc., (9) Imide-based; ethyleneimine, polyethyleneimine, etc., (10) Pyrazole system; examples thereof include pyrazole, 3-methylpyrazole, and 3,5-dimethylpyrazole.

Among these, the other preferable blocking agent is not particularly limited, but is selected from at least an active methylene-based and pyrazole-based blocking agent other than the oxime-based, amine-based, acid amide-based, malonic acid diester compound and β-ketoester compound. It is one kind, more preferably at least one kind selected from active methylene-based and pyrazole-based blocking agents other than oxime-based, 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 oxime-based blocking agents other than ketoester compounds.

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

In the blocked polyisocyanate composition of the present embodiment, the crystallization of the blocked polyisocyanate composition tends to be significantly suppressed by containing this monohydric alcohol compound.

The carbon number of the monohydric alcohol compound is the storage stability and compatibility when the blocked polyisocyanate composition is mixed with the polyvalent active hydrogen compound to obtain a thermosetting composition, and the crystallinity of the blocked polyisocyanate composition. From the viewpoint 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 further preferable. Further, in terms of ease of scattering of the solvent and low-temperature curability, the boiling point is preferably 200 ° C. or lower, more preferably 80 to 180 ° C., and even more preferably 90 to 160 ° C.

Examples of the monovalent 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 more of them can be selected and used.

The carbon number of the monohydric alcohol compound is higher than that of the terminal alkyl group bonded to the malonic acid diester and the β-ketoester in terms of compatibility between the blocked polyisocyanate composition and the polyvalent active hydrogen compound. Is preferable.

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

When the monohydric alcohol compound is contained in the blocked polyisocyanate composition, the storage stability and compatibility of the thermosetting composition containing the blocked polyisocyanate composition and the polyvalent active hydrogen compound are improved. Although the detailed factor is not clear, the above monohydric alcohol compound reacts with the unreacted isocyanate group contained in the blocked polyisocyanate or by the ester exchange reaction with the ester group contained in the blocked polyisocyanate. It is considered that the structural symmetry of the blocked polyisocyanate, the arrangement of the blocked polyisocyanate molecules, and the like can be broken, which makes it difficult for the blocked polyisocyanate composition to crystallize. When the blocked polyisocyanate composition is crystallized, the interaction with the polyvalent active hydrogen compound cannot be sufficiently taken and the compatibility is lowered. Therefore, it is considered that the compatibility is improved by suppressing the crystallization.

In the blocked polyisocyanate composition of the present embodiment, it is particularly preferable that at least a part of the unreacted isocyanate groups contained in the blocked polyisocyanate form a urethane bond with the monovalent alcohol compound. The amount of the urethane bond structure formed by the isocyanate group and 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), and the isocyanate group and β. When the number of moles of the bonded structure with the ketoester compound is (c), the molar ratio represented by (a) / ((a) + (b) + (c)) is 0.0020 or more and 0. More preferably less than .50.

According to the research 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 was found that crystallization is very unlikely to occur and the compatibility is superior. However, the above 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 blocked polyisocyanate of the present embodiment, and / or a terminal alkyl ester residue in the structure of the blocked polyisocyanate. It is a compound capable of an ester exchange reaction. As a result, the crystallization of the blocked polyisocyanate composition of the present embodiment tends to be suppressed.

The carbon number of the monohydric alcohol compound is preferably 3 or more and 10 or less, more preferably 4 or more and 9 or less, and further preferably 4 or more and 8 or less, from the viewpoint of storage stability, compatibility, and suppression of crystallinity. Further, from the viewpoint of ease of 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.

The monovalent alcohol compound having the above-mentioned carbon number and / or boiling point is not particularly limited, and 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- Included are butanol, n-heptanol, n-octanol, 2-ethyl-1-hexanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methylcarbitol, diethylcarbitol, propylene glycol monomethyl ether, cyclohexanol, phenol, and benzyl alcohol. , One or more of these can be selected and used.

The amount of the monohydric alcohol compound added is not particularly limited, but is preferably 10 equivalent% or more and 500 equivalent% or less, more preferably 20 equivalent% or more and 400 equivalent% or less, and further preferably 30 relative to the blocked isocyanate group. Equivalent% or more and 300 equivalent% or less.

By including the monohydric alcohol compound in the blocked polyisocyanate composition, storage stability and compatibility are improved. Although the detailed factor is not clear, the monohydric alcohol compound reacts with an unreacted isocyanate group or an ester exchange reaction with a terminal alkyl ester residue in the structure of the blocked polyisocyanate to cause a blocked polyisocyanate. It is presumed that the blocked polyisocyanate composition of the present embodiment is difficult to crystallize due to the fact that the structural symmetry, the arrangement of the polyisocyanate, etc. can be broken (however, the factor is not limited to this). ..

[Method for producing blocked polyisocyanate composition]
A method for producing the blocked polyisocyanate composition of the present embodiment will be described. The method for producing the blocked polyisocyanate composition of the present embodiment is a polyisocyanate derived from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, and a malonic acid diester compound and a malonic acid diester compound. Two steps, a first step of obtaining a blocked polyisocyanate from a blocking agent other than the above, and a subsequent second step of transesterifying the obtained blocked polyisocyanate with a monoalcohol (monohydric alcohol compound). Has a 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 at the same time with the polyisocyanate, or either of the blocking agents may be reacted first. After reacting with the polyisocyanate, the other blocking agent may be reacted.

In the blocking reaction (reaction between polyisocyanate and blocking agent) in the present embodiment, it is preferable to react so as to block all the isocyanate groups of the polyisocyanate. From this point of view, the molar ratio of the blocking agent to the isocyanate group in the polyisocyanate ((total number of moles of the blocking agent) / (number of moles of the 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, even more preferably 1.030, and even more preferably 1.045. The upper limit of the molar ratio is more preferably 1.35, still more preferably 1.20, and even more preferably 1.10. By setting the lower limit of the molar ratio to 1.0, the low temperature curability of the blocked polyisocyanate tends to be more reliably exhibited. On the other hand, by setting the upper limit of the molar ratio to 1.5 or less, it tends to be possible to suppress a decrease in dryness after painting.

The reaction of the first step can be carried out regardless of the presence or absence of the solvent. When a solvent is used, it is preferable to use a solvent that is inert to the isocyanate group. Specific examples of the solvent are not particularly limited, but for example, 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: A solvent can be appropriately selected and used from the group of ethers such as propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether according to the purpose and application. These solvents may be used alone or in combination of two or more.

A reaction catalyst (hereinafter, also referred to as “blocking reaction catalyst”, simply referred to as “catalyst”) can be used in the blocking reaction of the first step. Specific reaction catalysts are not particularly limited, and examples thereof include organometallic salts such as tin, zinc, and lead; metal alcoholates; and tertiary amines.

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

The amount of the catalyst added 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 amount of the catalyst added is small, the remaining amount of socyanate groups that are 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 blocked polyisocyanate composition of the present embodiment, in order to adjust the molar ratio of the keto-form structure and the enol-form structure and to secure the amount of methanetetracarbonyl structure produced, the above reaction catalyst takes time. It is preferable to add them continuously. The time required for dropping is preferably 2.0 minutes or more and 120 minutes or less. The lower limit of the time is more preferably 3.0 minutes, further 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 even more preferably 30 minutes. By setting the lower limit of the time to 2.0 minutes or more, when a malonic acid diester compound is used as a blocking agent in a large ratio, the content ratio of the molar ratio of the enol structure tends to be increased. Further, by increasing the amount of the methanetetracarbonyl structure produced, it tends to be easy to adjust to the range of the present embodiment. On the other hand, by setting the upper limit of the time to 120 minutes or less, it is possible to prevent the content ratio of the molar ratio of the enol structure from becoming too high, and the amount of methanetetracarbonyl structure produced does not become too large. It can be easily adjusted to the range of the embodiment, and there is a tendency that the reaction time extension can be suppressed. When the above reaction catalyst is mixed with a blocking agent and added to polyisocyanate, the content ratio of the keto structure tends to be extremely high.

When the reaction catalyst used may adversely affect the physical characteristics of the paint or coating film, it is preferable to inactivate the reaction catalyst with an acidic compound or the like. Specific examples of the acidic compound in this case are not particularly limited, but for example, inorganic acids such as hydrochloric acid, phosphite, and phosphoric acid; methanesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid methyl ester, and p-toluene. Sulphonic acid such as ethyl sulfonic acid or a derivative thereof; 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 of 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, and further preferably 40 ° C. or higher, from the viewpoint of suppressing side reactions and reaction efficiency. It is 100 ° C. or lower. By carrying out 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. Further, by carrying out 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 generally be 0.1 to 6 hours, but is preferably 0.5 to 4 hours from the viewpoint of optimizing the amount of urethane bond structure to be produced. .. When the reaction time is shortened, the remaining amount of isocyanate groups that are not blocked during the blocking reaction tends to increase.

Further, the reaction temperature and reaction time are preferably set to, for example, 50 to 180 ° C. and 10 to 480 minutes.

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

The blocked polyisocyanate composition of the present embodiment contains a blocked polyisocyanate composition and a monohydric alcohol in order to improve storage stability when blended with at least one selected from the group consisting of polyols, polyamines and alkanolamines. It is preferable to carry out the second step as a step of mixing and reacting with the compound.

The mixing temperature of 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 carrying out the reaction at a mixing temperature of 150 ° C. or lower, side reactions tend to be suppressed. Further, the mixing time tends to be shortened by carrying out the reaction at a mixing temperature of −20 ° C. or higher.

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

In the present embodiment, the polyisocyanate is not blocked by a blocking agent so as to form a urethane bond between the unreacted isocyanate group and the monohydric alcohol compound in the blocked polyisocyanate composition. Leave the isocyanate group of the reaction.

As a method of leaving an unblocked isocyanate group, for example, a method of reducing the amount of the blocking agent added in advance to be smaller than the molar amount of the isocyanate group of the polyisocyanate, a method of controlling the amount of the blocking reaction catalyst added, a reaction temperature or a reaction time. Examples include a method of controlling. These methods may be used alone or in combination.

Further, by simultaneously adding the blocking agent and the monohydric alcohol compound, a method of forming a urethane bond between the isocyanate group of the blocked polyisocyanate and the monohydric alcohol compound can also be adopted.

By the above method, a blocked polyisocyanate composition in which an unreacted isocyanate group in the blocked polyisocyanate and a monohydric alcohol compound form a urethane bond can be produced.

In the present embodiment, by heating the blocked polyisocyanate in the presence of a monohydric alcohol compound having an alkyl group having 4 or more carbon atoms, the transesterification reaction tends to be promoted and the storage stability tends to be improved. Further, by simultaneously heating and removing the alcohol desorbed by the transesterification reaction, the proportion of the alkyl group having 4 or more carbon atoms _{in R 1} and R _{2 in the above formula (V) is occupied by the present embodiment.} It can be adjusted to a range and tends to improve storage stability and compatibility.

The heating conditions for promoting the transesterification reaction _{may be any conditions as long as the transesterification of R 1} and R ₂ in the above formula (V) occurs, and can be adjusted at a desired temperature and time. However, the 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. The heating time is preferably 0.2 hours or more and 8 hours or less, and more preferably 0.5 hours or more and 5 hours or less.

The blocked polyisocyanate composition produced in the above step can achieve both low temperature curability, storage stability, and compatibility.

On the other hand, from a polyisocyanate derived from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, a malonic acid diisocyanate compound, and if necessary, a blocking agent other than the malonic acid diisocyanate compound. A blocked polyisocyanate composition containing a large amount of methanetetracarbonyl structure may be separately mixed with the produced blocked polyisocyanate to produce a blocked polyisocyanate composition. For example, the blocked polyisocyanate obtained in the same steps as in the first step and the second step is mixed with a separately manufactured block polyisocyanate having a high methanetetracarbonyl structure content ratio as the third step. This is a method for adjusting the methanetetracarbonyl structure content ratio of the entire obtained blocked polyisocyanate composition.

The block polyisocyanate having a high methanetetracarbonyl structure content ratio, which was separately produced, has a molar ratio of the malonic acid diester compound to 0.5 or more and 0.9 or less with respect to the isocyanate group of the polyisocyanate. It can be manufactured by performing the same process as in one process. The lower limit of the molar ratio is more preferably 0.55, still more preferably 0.60, and even more preferably 0.65. The upper limit of the molar ratio is more preferably 0.85, still more preferably 0.80, and even 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, and by setting the upper limit of the molar ratio to 1.0 or less, methanetetracarbonyl tends to be suppressed. There is a tendency that the amount of structure generated can be increased.

Further, it is preferable that the blocked polyisocyanate having a high methanetetracarbonyl structure ratio is also reacted by mixing a monohydric alcohol compound in the same step as the second step after the reaction of the polyisocyanate with the malonic acid diester compound.

The average number of isocyanate groups of the polyisocyanate used for the blocked 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 of the average number of isocyanate groups is 1.0 or more, the formation ratio of the methanetetracarbonyl structure tends to be increased, and when the upper limit of the average number of isocyanate groups is 4.0 or less, the formation ratio of the methanetetracarbonyl structure tends to be increased. There is a tendency that gelation during the production of the methanetetracarbonyl structure can be suppressed.

The mixing temperature of 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, and 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 blocked polyisocyanate composition of the present embodiment depending on the purpose and use.

The organic solvent to be added is not particularly limited, but for example, an aliphatic hydrocarbon solvent such as hexane, heptane, or octane; an alicyclic hydrocarbon solvent such as cyclohexane or methylcyclohexane; acetone, methylethylketone, methylisobutylketone, etc. Ketone solvents such as cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, methyl lactate, ethyl lactate; aromatics such as toluene, xylene, diethylbenzene, mesitylene, anisole, benzyl alcohol, phenylglycol, chlorobenzene and the like. Group-based solvent; Glycol-based solvent such as ethylene glycol monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether; Ether-based solvent such as diethyl ether, tetrahydrofuran, dioxane; dichloromethane , 1,2-Dichloroethane, chloroform and other halogenated hydrocarbon solvents; N-methyl-2-pyrrolidone and other pyroridone solvents; N, N-dimethylacetamide, N, N-dimethylformamide and other amide solvents; dimethyl Examples thereof include sulfoxide-based solvents such as sulfoxide; lactone-based solvents such as γ-butyrolactone; amine-based solvents such as morpholine; and mixtures thereof.

Further, another blocked polyisocyanate composed of a multimer of diisocyanate other than the aliphatic and alicyclic diisocyanates may be added to the blocked polyisocyanate composition of the present embodiment at an arbitrary ratio. At that time, the bound blocking agent may have the same structure as or different from that of the blocked polyisocyanate.

Further, the blocked polyisocyanate composition of the present embodiment has a curing accelerator, an antioxidant, an ultraviolet absorber, a light stabilizer, a pigment, a leveling agent, a plasticizer, a rheology control agent, and a surfactant, depending on the purpose and application. Various additives such as agents can be contained.

The curing acceleration catalyst is not particularly limited, but is, for example, a tin compound such as dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, dimethyltin dineodecanoate, and bis (2-ethylhexanoic acid) tin; 2- Zinc compounds such as zinc ethylhexanate and zinc naphthenate; titanium compounds such as titanium 2-ethylhexanoate and titanium diisopropoxybis (ethylacetonate); cobalt compounds such as cobalt 2-ethylhexanoate and cobalt naphthenate; Bismus 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 can be mentioned.

The antioxidant is not particularly limited, and examples thereof include hindered phenol compounds, phosphorus compounds, and sulfur compounds.

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

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.

The leveling agent is not particularly limited, and examples thereof include silicone oil and the like.

The plasticizer is not particularly limited, and examples thereof include phthalates, phosphoric acid compounds, polyester compounds, and the like.

The rheology control agent is not particularly limited, and examples thereof include hydroxyethyl cellulose, urea compounds, and microgels.

The surfactant is not particularly limited, and examples thereof include known anionic surfactants, cationic surfactants, amphoteric surfactants, and the like.

Further, in the polyisocyanate composition and the blocked polyisocyanate composition according to the present embodiment, the content of the above-mentioned other additives is preferably 0 to 80% by mass, preferably 0 to 70% by mass. It is preferably 0 to 60% by mass, more preferably 0 to 60% by mass.

[One-component coating composition]
The one-component coating composition of the present embodiment contains the blocked polyisocyanate composition of the present embodiment and at least one of a polyol, a polyamine and an alkanolamine. Further, the one-component coating composition preferably contains at least a polyol. In order to improve the storage stability of the one-component coating composition, the blocked polyisocyanate composition of the present embodiment preferably further contains the above-mentioned monohydric alcohol compound.

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

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

The polyester polyol is not particularly limited, and is, 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, and terephthalic acid. Polyester polyols and polyhydric alcohols obtained by condensation reaction of a single or mixture with a polyhydric alcohol selected from the group of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin. Examples thereof include polycaprolactones obtained by ring-opening polymerization of ε-caprolactone using.

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

The polyether polyols are not particularly limited, but for example, a hydroxide such as lithium, sodium and potassium, and a strongly basic catalyst such as alcoholate and alkylamine are used alone or in a mixture of polyvalent hydroxy compounds. , Ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide and other alkylene oxides alone or in admixture, and obtained by reacting a polyfunctional compound such as ethylenediamine with an alkylene oxide. Polyether polyols; Examples thereof include so-called polymer polyols obtained by polymerizing acrylamide and the like using these polyether polyols as a medium.

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) of one statistical molecule of polyol is preferably 2.0 or more. When the average number of hydroxyl groups of the polyol is 2.0 or more, it tends to be possible to suppress a decrease in the crosslink density of the obtained coating film.

The fluorine polyol is a polyol containing fluorine in the molecule, and is not particularly limited. For example, fluoroolefins, cyclovinyl ethers, and hydroxyalkyls disclosed in JP-A-57-34107 and JP-A-61-275311. Examples thereof include copolymers such as vinyl ether and monocarboxylic acid vinyl ester.

The polycarbonate polyols are not particularly limited, and are, for example, low molecular weight carbonate compounds such as dialkyl carbonates such as dimethyl carbonate, alkylene carbonates such as ethylene carbonate, and diaryl carbonates such as diphenyl carbonate, and low molecular weight compounds used in the above-mentioned polyester polyols. Examples thereof include those obtained by polycondensing a polyol.

The polyurethane polyol is not particularly limited, but can be obtained, for example, by reacting the polyol with a polyisocyanate.

The hydroxyl value of the polyol per resin is preferably 10 mgKOH / resin g or more and 300 mgKOH / resin g or less. When the hydroxyl value per resin is 10 mgKOH / resin g or more, it tends to be possible to suppress the decrease in the crosslink density and sufficiently achieve the desired physical properties of the present embodiment. On the other hand, when the hydroxyl value per resin is 300 mgKOH / resin g or less, it tends to be possible to suppress an excessive increase in the crosslink density and maintain a high degree of mechanical properties of the coating film.

The acid value of the polyol per resin is preferably 5.0 mgKOH / resin g or more and 150 mgKOH / resin g or less, more preferably 8.0 mgKOH / resin g or more and 120 mgKOH / resin g or less, and further preferably 10 mgKOH / Resin g or more and 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 the acid value is 150 mgKOH / resin g or less, the deterioration of the water resistance of the coating film can be suppressed. There is a tendency to be able to do it.

Among the polyols listed above, acrylic polyols and polyester polyols are more preferable. In the coating composition when a polyol is used, 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 here, those having two or more primary amino groups or secondary amino groups in one molecule are preferably used, and among them, those having three or more in one molecule are more preferable.

Further, the alkanolamine here means a compound having an amino group and a hydroxyl group in one molecule. The alkanolamine is not particularly limited, and is, for example, monoethanolamine, diethanolamine, aminoethylethanolamine, N- (2-hydroxypropyl) ethylenediamine, mono-, di- (n- or iso-) propanolamine, ethylene glycol. -Bis-propylamine, neopentanolamine, and methylethanolamine can be mentioned.

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

The one-component coating composition of the present embodiment may be used as an antioxidant such as hindered phenol, as an ultraviolet absorber such as benzotriazole and benzophenone, and as pigments such as titanium oxide, carbon black, indigo and quinacridone, if necessary. , Pearl mica and the like, metal powder pigments such as aluminum, rheology control agents such as hydroxyethyl cellulose, urea compounds, microgels and the like, and curing accelerators such as tin compounds, zinc compounds, amine compounds and the like may be contained.

[Painted articles]
The coated article of the present embodiment is coated with the one-component coating composition of the present embodiment. For example, the one-component coating composition of the present embodiment can be used for roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, etc. to make metals such as steel plates and surface-treated steel plates, and materials such as plastics and inorganic materials. , Preferred as a primer, intermediate coat, or top coat, to give a painted article. This one-component coating composition further imparts cosmetic properties, weather resistance, acid resistance, rust resistance, chipping resistance, adhesion, etc. to pre-coated metals including rust-preventive steel sheets, automobile coatings, plastic coatings, etc. Suitable for use. In addition, this one-component coating composition is also useful as a urethane raw material for adhesives, pressure-sensitive adhesives, elastomers, foams, surface treatment agents and the like.

[Coating film]
The coating film of the present embodiment is formed by the one-component coating composition of the present embodiment. That is, the one-component coating composition of the present embodiment is coated by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, etc., and then undergoes a baking step to form the coating film of the present embodiment. Can be done. The one-component coating composition used for forming this coating film preferably undergoes a baking step to form a crosslinked coating film. The crosslinked coating film after curing of the one-component coating composition has not only a urethane bond derived from polyisoanate before the blocking reaction but also a polar group such as an amide bond derived from a blocked isocyanate group and an ester bond. Therefore, the crosslinked coating film formed from the one-component coating composition of the present embodiment is subjected to laminated coating or recoating in addition to the characteristics of a general urethane crosslinked coating film such as chemical resistance, heat resistance, and water resistance. When this is done, hydrogen bonding between layers becomes possible, and the adhesion between layers is excellent. Even in a coating film in which the crosslinked structure is not completely formed after the baking step, since it has the above-mentioned polar groups, it is excellent in that it has excellent adhesion at the time of laminated coating or recoating, as in the case of the crosslinked coating film.

Further, when several layers of coating liquids are laminated wet-on-wet as in the case of painting a new car line of an automobile, the organic amine compound is present in the coating composition of the present embodiment or in the crosslinked coating film after curing. It may also act as a catalyst for the cross-linking reaction of the lower or upper layers.

[Thermosetting composition, cured product]
The thermosetting composition of the present embodiment contains the above-mentioned blocked polyisocyanate composition and a multivalent active hydrogen compound. A cured product can be obtained by heat-curing the thermosetting composition. Specifically, the thermosetting composition of the present embodiment can be produced by mixing the block polyisocyanate composition with a multivalent active hydrogen compound. Further, by heating the thermosetting composition of the present embodiment, the blocked polyisocyanate and the active hydrogen in the polyvalent active hydrogen compound undergo a transesterification reaction to obtain a cured product.

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

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

The multivalent active hydrogen compound of the present embodiment is a compound in which two or more active hydrogens are bonded in the molecule. Examples of the active hydrogen compound are not particularly limited, and examples thereof include polyols, polyamines, alkanolamines, and polythiols, but polyols are preferable.

The polyamine is not particularly limited, and is, for example, diamines such as ethylenediamine, propylenediamine, butylenediamine, triethylenediamine, hexamethylenediamine, 4,4'-diaminodicyclohexylmethane, piperazin, 2-methylpiperazine, and isophoronediamine; Chain polyamines having three or more amino groups such as bishexamethylenetriamine, diaminetriamine, triethylenetetramine, tetraethylenepentamine, pentamethylenehexamine, tetrapropylenepentamine; 1,4,7,10,13,16 Cyclic polyamines such as -hexaazacyclooctadecane, 1,4,7,10-tetraazacyclodecane, 1,4,8,12-tetraazacyclopentadecane, 1,4,8,11-tetraazacyclotetradecane Can be mentioned.

The alkanolamine is not particularly limited, but for example, monoethanolamine, diethanolamine, triethanolamine, aminoethylethanolamine, N- (2-hydroxypropyl) ethylenediamine, mono-, di- (n- or iso-). ) Propanolamine, ethylene glycol-bis-propylamine, neopentanolamine, methylethanolamine and the like can be mentioned.

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

The polyol is not particularly limited, and examples thereof include polyester polyol, acrylic polyol, polyether polyol, polyolefin polyol, fluorine polyol, polycarbonate polyol, polyurethane polyol, and epoxy resin.

The polyester polyol is not particularly limited, and examples thereof include polyester polyols and polycaprolactones. The polyester polyol is not particularly limited, but is obtained, for example, by a condensation reaction of a dibasic acid alone or a mixture with a polyhydric alcohol alone or a mixture. The dibasic acid is not particularly limited, but is one selected from the group consisting of, for example, succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and carboxylic acid of terephthalic acid. Alternatively, two or more kinds of dibasic acids can be mentioned. The polyhydric alcohol is not particularly limited, and for example, one or more polyhydric alcohols selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin can be used. Can be mentioned. The polycaprolactones are not particularly limited, but can be obtained, for example, by ring-opening polymerization of ε-caprolactone using a polyhydric alcohol.

The acrylic polyol is not particularly limited, and 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. Examples thereof include those obtained by copolymerizing alone or with a mixture.

The polyether polyol is not particularly limited, but for example, a hydroxide such as lithium, sodium and potassium; a strong basic catalyst such as alcoholate and alkylamine can be used to prepare a single or a mixture of polyvalent hydroxy compounds. Polyether polyols obtained by adding alone or a mixture of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide and styrene oxide; polys obtained by reacting a polyfunctional compound such as ethylenediamine with alkylene oxide. Ether polyols; Examples thereof include so-called polymer polyols obtained by polymerizing acrylamide and the like using the above-mentioned polyethers as a medium.

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 fluorine polyol is not particularly limited, but is, for example, a polyol containing fluorine in the molecule, for example, fluoroolefins and cyclos disclosed in JP-A-57-34107 and JP-A-61-275311. Examples thereof include copolymers of vinyl ether, hydroxyalkyl vinyl ether, monocarboxylic acid vinyl ester and the like.

The polycarbonate polyol is not particularly limited, and for example, a low molecular weight carbonate compound such as a dialkyl carbonate such as dimethyl carbonate, an alkylene carbonate such as ethylene carbonate, and a diaryl carbonate such as diphenyl carbonate, and a low molecular weight polymer used for the above polyester polyol. Examples thereof include those obtained by polycondensing a polyol.

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 has two or more epoxy groups in one molecule, and a resin known per se can be used. Examples of the epoxy resin include a bisphenol type epoxy resin obtained by adding epochlorohydrin 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 needed.

Among the polyols listed above, acrylic polyols and polyester polyols are preferable.

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, it tends to be possible to suppress the decrease in the crosslink density and sufficiently achieve the desired physical properties of the present embodiment. On the other hand, when the hydroxyl value per resin is 300 mgKOH / resin g or less, it tends to be possible to suppress an excessive increase in the crosslink density and maintain a high degree of mechanical properties of the coating film. 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 the present embodiment may further contain other curing agents such as a melamine-based curing agent and an epoxy-based curing agent.

The melamine-based curing agent is not particularly limited, and examples thereof include a completely alkyl etherified melamine resin, a methylol-based melamine resin, and an imino-based melamine resin having an imino group in part.

When a melamine-based curing agent is used in combination as a curing agent, it is effective to further add an acidic compound. Specific examples of the acidic compound include, but are not limited to, carboxylic acid, sulfonic acid, acidic phosphoric acid ester, and phosphite ester.

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

The sulfonic acid is not particularly limited, and examples thereof include paratoluenesulfonic acid, dodecylbenzenesulfonic acid, and dinonylnaphthalenedisulfonic acid.

The acidic phosphoric acid 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 ester is not particularly limited, and is, for example, diethyl phosphite, dibutyl phosphite, dioctyl phosphite, dilauryl phosphite, monoethyl phosphite, monobutyl phosphite, monooctyl phosphite, and monolauryl phos. Fight can be mentioned.

The epoxy-based curing agent is not particularly limited, and for example, aliphatic polyamines, alicyclic polyamines, aromatic polyamines, acid anhydrides, phenol novolacs, polymercaptans, aliphatic tertiary amines, aromatic tertiary amines, and imidazoles. Examples include compounds and Lewis acid complexes.

The epoxy-based curing agent is not particularly limited, and for example, aliphatic polyamines, alicyclic polyamines, aromatic polyamines, acid anhydrides, phenol novolacs, polymercaptans, aliphatic tertiary amines, aromatic tertiary amines, and imidazoles. Examples include compounds and Lewis acid complexes.

[Use]
The blocked 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, a casting composition, and various surface treatment agent compositions such as a fiber treatment agent. Various elastomer compositions; cross-linking agents such as foam compositions; modifiers; can be used as additives.

The coating composition containing the block polyisocyanate composition of the present embodiment is suitably used as a primer, an intermediate coating, and a top coating on various materials by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, and the like. To. In addition, this paint composition is used to further impart cosmetic properties, weather resistance, acid resistance, rust resistance, chipping resistance, adhesion, etc. to pre-coated metals including rust-preventive steel sheets, automobile coatings, plastic coatings, etc. It is preferably used.

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

The adherend to which the curable composition or the like containing the blocked polyisocyanate composition of the present embodiment can be used is not particularly limited, but for example, glass; various metals such as aluminum, iron, zinc steel plate, copper and stainless steel. Porous members such as wood, paper, mortar, and stone; members coated with fluorine, urethane, acrylic urethane, etc .; Curing of sealing materials such as silicone-based cured products, modified silicone-based cured products, urethane-based cured products, etc. Goods; 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, glass fiber; Non-woven fabric, polyester, acrylic, polycarbonate , Films and plates of resins such as triacetyl cellulose and polyolefin; examples thereof include an ultraviolet curable acrylic resin layer, printing ink, and inks such as UV ink.

Hereinafter, the present embodiment will be described in more detail by way of examples, but the present embodiment is not limited to these examples. The methods for measuring and evaluating various physical properties will be described below.

(Physical characteristics 1) NCO content (mass%)
The NCO content (isocyanate content, mass%) of the polyisocyanate was measured as follows. To a triangular 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. Then, 10 mL of a toluene solution of 2N-n-butylamine was added, the mixture was completely mixed, and the mixture was left at room temperature for 15 minutes. Further, 70 mL of isopropyl alcohol was added to this solution, and the mixture was completely mixed. This solution was titrated with a 1N hydrochloric acid solution (Factor F) using an indicator to give a titration value of V ₂ mL. The same titration operation was performed without using polyisocyanate to obtain a _{titration value of V 1 mL.} From the obtained titration value V ₂ mL and the titration value V ₁ mL, the NCO content of polyisocyanate was calculated based on the following formula.
NCO content = (V ₁ −V ₂ ) × F × 42 / (W × 1000) × 100

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

(Physical Properties 3) Number Average Molecular Weight The number average molecular weight of polyisocyanate was determined by the polystyrene-based number average molecular weight measured by gel permeation chromatography (hereinafter abbreviated as “GPC”) using the following apparatus.
Equipment: "HLC-8120GPC" manufactured by Tosoh (trade name)
Column: "TSKgel SuperH1000" (trade name) manufactured by Tosoh Co., Ltd. x 1
"TSKgel SuperH2000" (trade name) x 1
"TSKgel SuperH3000" (trade name) x 1 Carrier: Tetrahydrofuran Detection method: Differential refractometer

The number average molecular weight of the polyol was determined by the polystyrene-based number average molecular weight measured by GPC below.
Equipment: "HLC-8120GPC" manufactured by Tosoh (trade name)
Column: Tosoh "TSKgel SuperHM-H" (trade name) x 2 Carrier: N, N-dimethylformamide Detection method: Differential refractometer

(Physical characteristics 4) Residual HDI concentration (mass%)
The residual HDI concentration of 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 to 0.04 g of nitrobenzene (internal standard solution) was added and weighed precisely. Finally, after adding about 9 mL of ethyl acetate, the lid was tightly mixed and the sample was prepared. The above-mentioned adjusting solution was analyzed by gas chromatography under the following conditions and quantified.
Equipment: "GC-8A" manufactured by SHIMADZU
Column: "Silicone OV-17" manufactured by Shinwa Kako Co., Ltd.
Column oven temperature: 120 ° C
Injection / detector temperature: 160 ° C

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

(Physical characteristics 6) Effective NCO content (mass%)
The effective NCO content of the blocked polyisocyanate was determined as follows. The effective NCO content (% by mass) here is for quantifying the amount of blocked isocyanate groups present in the blocked polyisocyanate composition after the blocking reaction and which can be involved in the cross-linking reaction. Expressed as% by mass and calculated by the following formula.
{(Solid content (mass%) of blocked polyisocyanate composition) x (mass of polyisocyanate used in reaction x isocyanate group content of precursor polyisocyanate%)} / (blocked polyisocyanate composition after blocking reaction) Resin mass)
When the sample was diluted with a solvent or the like, the value in the diluted state is described.

(Physical characteristics 7) Solid content concentration (mass%)
After precisely weighing an aluminum dish with a bottom diameter of 38 mm, the block polyisocyanate composition of Example or Comparative Example is precisely weighed with about 1 g placed on the aluminum dish (W1) to make the block polyisocyanate composition uniform in thickness. After the 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 content concentration = W2 / W1 × 100

(Physical characteristics 8) Molar ratio of keto-enol to keto-enol The molar ratio of keto / enol was determined by 1H-NMR measurement using "Biospin Avance 600" (trade name) manufactured by Bruker. The specific measurement conditions were as follows.
Equipment: Bruker's "Biospin Avance 600" (trade name)
Solvent: Deuterated chloroform Number of integrations: 256 times Sample concentration: 5% by mass
Chemical shift standard: Tetramethylsilane was set to 0 ppm.

・エノール体ＮＨプロトン：（下記式（Ｘ）で示すマロン酸ジエチル）９．８ｐｐｍ付近、（下記式（ＸＩ）で示すアセト酢酸エチル）９．２ｐｐｍ付近

The integral value of the following signals was divided by the number of hydrogens being measured, and each molar ratio was calculated from that value.
-Ketone NH proton: (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 proton: (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 characteristics 9) Methane tetracarbonyl structure ratio (mol%)
The methanetetracarbonyl structure ratio of the blocked polyisocyanate composition was determined as follows. ^{By 1} H-NMR measurement using "Avance 600" (trade name) manufactured by BrukerBiospin, methanetetracarbonyl structure / (methanetetracarbonyl structure + methanetricarbonyl structure keto form + methanetricarbonyl structure enol form) The molar ratio was calculated. The specific measurement conditions were as follows.
Equipment: "Avance 600" manufactured by BrukerBiospin (trade name)
Solvent: Deuterated chloroform Number of integrations: 256 times Sample concentration: 5.0% by mass
Chemical shift standard: Tetramethylsilane was set to 0 ppm.

・メタントリカルボニル構造（下記式（ＩＶ）で示される構造）のエノール体ＮＨプロトン：９．８ｐｐｍ付近：積分値÷１

・メタンテトラカルボニル構造（下記式（ＶＩＩ）で示される構造）のＮＨプロトン：８．０ｐｐｍ付近：積分値÷２

The integral value of the following signals was divided by the number of carbons being measured, and each molar ratio was calculated from that value.
-Ketone NH proton of methanetricarbonyl structure (structure represented by the following formula (III)): Near 7.3 ppm: Integral value ÷ 1

-Enol NH proton of methanetricarbonyl structure (structure represented by the following formula (IV)): Near 9.8 ppm: Integral value ÷ 1

-NH proton of methane tetracarbonyl structure (structure represented by the following formula (VII)): around 8.0 ppm: integrated value / 2

(Physical Properties 10) Mol Ratio of Urethane Bond between Isocyanate Group and Monovalent Alcohol Compound ¹ H-NMR of the blocked polyisocyanate composition obtained in Synthesis Examples 2 to 7 was measured, and the monovalent alcohol compound and the isocyanate group were bonded. Amino group (around 4.8 ppm) due to the urethane bond obtained by the above, and an amino group adjacent to the amide form formed by the bond between the isocyanate group and diethyl malonate (around 7.3 ppm: keto form). , 8.0 ppm: diamide diester, 9.8 ppm: enol), and amino group adjacent to the amide formed by bonding the isocyanate group and ethyl acetoacetate (7.2 ppm: keto). From the area of the peak caused by the body (around 9.2 ppm: enol body), the molar ratio of the urethane bond was calculated by the following formula.
The molar ratio of urethane bonds = (a) / ((a) + (b) + (c))
(B): Number of amino groups adjacent to the amide compound formed by bonding the isocyanate group and diethyl malonate (= peak area around 7.3 ppm + peak area around 8.0 ppm / 2 + peak area around 9.8 ppm) : Since the peak (diamide diester) near 8.0 ppm has two amino groups in one bond structure, 1/2 of the peak area was defined as the number of bond structures), and the isocyanate group and malon were obtained. Number of bonded structures (number of moles) with acid diester compound.
(C): With the isocyanate group obtained from the number of amino groups adjacent to the amide compound formed by bonding the isocyanate group and ethyl acetoacetate (= peak area near 7.2 ppm + peak area near 9.2 ppm). Number of bonded structures (number of moles) with acetoacetic ester compound.
(A): Isocyanate group and monovalent obtained from the number of amino groups (= peak area around 4.8 ppm) due to the urethane bond obtained by bonding the isocyanate group with n-butanol, isobutanol or isopropanol. Number of urethane bond structures (number of moles) with alcohol compounds.

(Physical Properties 11) Molar Ratio of Blocked Isocyanate Structure Using each of the blocked polyisocyanate compositions obtained in Examples and Comparative Examples as a sample, any of the terminal alkyl groups bonded to diethyl malonate has 4 or more and 8 or less carbon atoms. The molar ratio of the blocked isocyanate structure as a group (hereinafter referred to as "molar ratio M") was determined as follows. The molar ratio M was determined as follows by ¹ H-NMR measurement using "Avance 600" (trade name) manufactured by BrukerBiospin. The specific measurement conditions were as follows.
Equipment: "Avance 600" manufactured by BrukerBiospin (trade name)
Solvent: Deuterated chloroform Number of integrations: 256 times Sample concentration: 5.0% by mass
Chemical shift standard: Tetramethylsilane was set to 0 ppm.
¹ H-NMR of the blocked polyisocyanate composition was measured, and the mole fraction M was calculated from the peak area caused by the proton (16.4 to 16.6 ppm) of the OH group of the enol compound of the malonic acid diester from the following formula. Calculated.
Mole ratio M = a / b
a: At least one of the terminal alkyl groups is an alkyl group having 4 or more carbon atoms and 8 or less carbon atoms. The peak area of the proton b: The total peak area of the proton.

(Evaluation 1) Low-temperature curability "Setalux 1152" (acrylic polyol, trade name manufactured by Nuplex Resins, hydroxyl value 138 mgKOH / resin g, solid content concentration 51% by mass) and blocked polyisocyanate composition, NCO / OH = 1 Mix so that it becomes .0, and add butyl acetate to Ford Cup No. The temperature was adjusted to 20 seconds / 23 ° C. in 4 to obtain an α-paint solution.

The obtained α-paint solution was coated on a PP plate with an air spray gun 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 90 ° C. for 20 minutes to obtain a cured coating film. ..

After baking the obtained cured coating film, leave it at 20 ° C. for 1 hour, peel it off from the PP plate, immerse it in acetone at 20 ° C. for 24 hours, and then determine the value (gel fraction) of the mass of the undissolved portion with respect to the mass before immersion. It was 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) Adhesion to the upper coating film The α-paint solution obtained in (Evaluation 1) above 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 a minute, it was baked at 90 ° C. for 20 minutes to obtain an α coating film layer 1. The adhesion test of the α coating film layer 1 with the mild steel plate was performed according to JIS K5600-5-6. As a result, no peeling was observed, including some floating.

70 parts of "Setalux 1767" (acrylic polyol, trade name manufactured by Nuplex Resins, hydroxyl value 150 mgKOH / resin g, solid content 65% by mass), hexamethoxymethylated melamine resin "Simel (registered trademark) 300" manufactured by Nippon Cytec Co., Ltd. After mixing 30 parts by mass and 1 part by mass of p-toluenesulfonic acid, with butyl acetate, Ford Cup No. The temperature was adjusted to 20 seconds / 23 ° C. in 4 to obtain a β-paint solution.

Separately, the α-paint solution obtained in the above (evaluation 1) is coated on a mild steel plate with an air spray gun so that the dry film thickness is 40 μm, dried at a temperature of 23 ° C. for 30 minutes, and then dried at 90 ° C. for 20 minutes. It was baked to obtain an α coating film layer 2. The α coating film 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 coat a multi-layer coating having an α layer and a β layer. A film was obtained. The adhesion test of the obtained multi-layer coating film was carried out according to JIS K5600-5-6. Evaluation was made according to the following criteria.
⊚: Peeling coating film, no floating ○: Partially floating on the cut part Δ: Less than half of the peeling coating film ×: More than half of the peeling coating film

(Evaluation 3) Compatibility The α-paint solution obtained in the above (Evaluation 1) was coated on a glass plate with an air spray gun so as to have a dry film thickness of 80 μm. It was dried at a temperature of 23 ° C. for 30 minutes, baked at 90 ° C. for 20 minutes, and then cooled. It was visually observed and evaluated according to the following criteria.
◯: Transparent △: Slightly turbid ×: Strong turbidity

[Production Example 1] Polyisocyanate P-1
The inside of a 4-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube, and a dropping funnel is made into a nitrogen atmosphere, and 1100 parts by mass of HDI and 1.2 parts by mass of 1,3-butanediol are charged and reacted under stirring. The temperature inside the vessel was maintained at 80 ° C. for 2 hours. After that, the temperature inside the reactor was maintained at 60 ° C., tetrabutylammonium acetate was added, and when the NCO content of the reaction solution reached 41.3% 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 21.0%, the viscosity at 25 ° C. was 3800 mPas, the residual HDI concentration was 0.2% by mass, and the average number of isocyanate groups was 3. A polyisocyanate P-1 of .6 was obtained.

[Production Example 2] Polyisocyanate P-2
The inside of a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube is made into a nitrogen atmosphere, and 100 parts by mass of HDI and 3.3 parts by mass of trimethylol propane are charged, and the temperature inside the reactor is set to 80 under stirring. It was kept at ° C. for 2 hours. After that, the temperature inside the reactor was maintained at 60 ° C., tetrabutylammonium acetate was added, and when the NCO content of the reaction solution reached 36.3% by mass, phosphoric acid was added to stop the reaction. After filtering the reaction solution, 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 25,000 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
The inside of a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube is made into a nitrogen atmosphere, 100 parts by mass of HDI is charged, the temperature inside the reactor is maintained at 60 ° C. under stirring, and tetrabutylammonium acetate is added. When the NCO content of the reaction solution reached 43.8% by mass, phosphoric acid was added and the reaction was stopped. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporator, and the NCO content was 19.5%, the viscosity at 25 ° C. was 1700 mPas, 23.0%, and the residual HDI concentration was 0.2% by mass. An isocyanurate-type polyisocyanate P-3 having an average number of isocyanate groups of 3.2 was obtained.

[Example 1] Block polyisocyanate composition B-1
The inside of a four-necked flask equipped with a stirrer, a thermometer, a reflux cooling tube, and a nitrogen blowing tube is made into a nitrogen atmosphere, and 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 parts by mass of a 28% sodium methylate solution was added at a rate of 0.16 parts by mass / min at room temperature, and the reaction was carried out at 60 ° C. for 6 hours. Then, 74 parts by mass of 1-butanol was added, and stirring was continued at that temperature for 2 hours. To this, 0.8 parts by mass of monophosphate (2-ethylhexyl) was added, and the block polyisocyanate composition B had an effective NCO content of 7.1%, a solid content concentration of 60% by mass, and a malonic acid diester adduct ratio of 80 mol%. I got -1. ¹ H-NMR measurement of the obtained blocked polyisocyanate composition B-1 was carried out, and the molar ratio of the keto form to the enol form in the blocked polyisocyanate composition and the methanetetracarbonyl structure ratio in the isocyanate-malonic acid diester bond were carried out. , The molar ratio of urethane bonds between the isocyanate group and the monohydric alcohol compound, and the molar ratio of the blocked isocyanate structure were quantified. In addition, the above-mentioned evaluations (evaluation 1) to (evaluation 3) were performed. The results obtained are shown in Table 1.

[Examples 2 and 3, Reference Example A, Examples 5 and 6, Comparative Examples 1 and 2]
The blocked polyisocyanate composition in the same manner as in Example 1 except that the formulations shown in Table 1 or Table 2 are used in Examples 2 and 3, Reference Example A, Examples 5 and 6, and Comparative Examples 1 and 2. B-2 to B-6 and B-8 to B-9 were obtained. The physical characteristic values and evaluation results of the obtained blocked polyisocyanate composition are shown in Tables 1 and 2.

[Example 7]
The inside of a four-necked flask equipped with a stirrer, a thermometer, a reflux cooling tube, and a nitrogen blowing tube is made into a nitrogen atmosphere, and 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 parts by mass of a 28% sodium methylate solution was added at a rate of 0.05 parts by mass / minute at room temperature, and the reaction was carried out at 60 ° C. for 6 hours. Then, 74 parts by mass of 1-butanol was added, and stirring was continued at that temperature for 2 hours while flowing nitrogen. To this, 0.8 parts by mass of monophosphate (2-ethylhexyl) was added, and the block polyisocyanate composition B had an effective NCO content of 7.1%, a solid content concentration of 60% by mass, and a malonic acid diester adduct ratio of 80 mol%. I got -7. ¹ H-NMR measurement of the obtained blocked polyisocyanate composition B-7 was carried out, and the molar ratio of the keto form to the enol form in the blocked polyisocyanate composition and the methanetetracarbonyl structure ratio in the isocyanate-malonic acid diester bond were carried out. , The molar ratio of urethane bonds between the isocyanate group and the monohydric alcohol compound, and the molar ratio of the blocked isocyanate structure were quantified. In addition, the above-mentioned evaluations (evaluation 1) to (evaluation 3) were performed. The results obtained are shown in Table 1.

[Comparative Example 3]
In the formulation shown in Table 2, the 28% sodium methylate solution was mixed in advance with the blocking agents diethyl malonate and ethyl acetoacetate, and the mixture was gradually added at room temperature in the same manner as in Example 1. The block polyisocyanate composition B-10 was obtained. Table 2 shows the physical characteristics and evaluation results of the obtained blocked polyisocyanate composition.

From the results of the above Examples and Comparative Examples, the blocked polyisocyanate composition of the present embodiment has good adhesion to the upper coating film while maintaining low temperature curability to the extent that it can be crosslinked at a baking temperature of 100 ° C. or lower. It was found that it was excellent and had excellent compatibility with polyol.

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

(Synthesis Example 1)
(Synthesis of polyisocyanate)
The inside of a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube and a dropping funnel is made into a nitrogen atmosphere, 1000 g of hexamethylene diisocyanate (HDI) is charged, and the temperature inside the reactor is maintained at 60 ° C. under stirring. did. Then, 2.1 g of tetramethylammonium acetate (2-butanol 5.0% by mass solution) was added as an isocyanurate-forming reaction catalyst to carry out the reaction. After 4 hours, the end point of the reaction was confirmed by measuring the refractive index of the reaction solution, and 0.2 g of phosphoric acid (85% by 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)
The inside of a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube was made into a nitrogen atmosphere, 100 parts of the polyisocyanate obtained in Synthesis Example 1 and 42.3 parts of butyl acetate were charged, and diethyl malonate was charged. A mixture of 71.1 parts, 14.5 parts of ethyl acetoacetate and 0.8 parts of a 28% sodium methylate methanol solution was added at room temperature, and the reaction was continued at 80 ° C. for 1 hour. Then, 76.0 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 2 hours.

Table 3 shows the effective NCO group content and molar ratio of the blocked polyisocyanate composition A having a block polyisocyanate of 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, and 28% sodium methylate methanol. A mixture of 0.8 parts of the solution was added at room temperature and the reaction was continued at 80 ° C. for 1 hour. Then, 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 in which the blocked polyisocyanate is 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, and 28% sodium methylate methanol. A mixture of 0.8 parts of the solution was added at room temperature and the reaction was continued at 80 ° C. for 1 hour. Then, 93.0 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 2 hours.

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

(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, and 28% sodium methylate methanol. A mixture of 0.4 parts of the solution was added at room temperature and the reaction was continued at 80 ° C. for 0.5 hours. Then, 93.0 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 2 hours.

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

(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, and 28% sodium methylate methanol. A mixture of 0.8 parts of the solution was added at room temperature and the reaction was continued at 80 ° C. for 0.5 hours. Then, 76.0 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 E having 60% by mass of the blocked polyisocyanate.

(Synthesis Example 7)
(Production of Block Polyisocyanate Composition F)
In Synthesis Example 2, the blocked polyisocyanate composition F was synthesized by the same method except that the amount of 28% sodium methylate methanol solution was 1.5 parts.

Table 3 shows the effective NCO group content and molar ratio of the blocked polyisocyanate composition F having 60% by mass of the blocked polyisocyanate.
(Synthesis Example 8)
(Production of Block Polyisocyanate Composition G)
In Synthesis Example 2, the blocked polyisocyanate composition G was synthesized by the same method except that the reaction temperature and the reaction time were set to 60 ° C. and 3 hours.

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

(Synthesis Example 9)
(Production of Block Polyisocyanate Composition H)
In Synthesis Example 2, the blocked polyisocyanate composition H was synthesized by the same method except that 1-butanol was changed to isobutanol.

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

(Synthesis Example 10)
(Production of Block Polyisocyanate Composition I)
In Synthesis Example 2, the blocked polyisocyanate composition I was synthesized by the same method 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 mass of the blocked polyisocyanate.

(Synthesis Example 11)
(Production of Block Polyisocyanate Composition J)
In Synthesis Example 2, the blocked polyisocyanate composition J was synthesized by the same method except that 4.0 parts of a 28% sodium methylate methanol solution was added.

Table 3 shows the effective NCO group content and molar ratio of the blocked polyisocyanate composition J in which the blocked polyisocyanate is 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, and 28% sodium methylate methanol. A mixture of 0.8 parts of the solution was added at room temperature and the reaction was continued at 80 ° C. for 0.5 hours. Then, 127.4 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 2 hours.

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

(Synthesis Example 13)
(Production of Block Polyisocyanate Composition L)
In Synthesis Example 2, the blocked polyisocyanate composition L was synthesized by the same method except that the reaction temperature and the reaction time were set to 80 ° C. and 0.2 hours.

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

(Synthesis Example 14)
(Production of Block Polyisocyanate Composition M)
In Synthesis Example 2, the blocked polyisocyanate composition M was synthesized by the same method except that the reaction temperature and the 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 in which the blocked polyisocyanate is 60% by mass.

[Evaluation methods]
The methods for evaluating various physical characteristics of the blocked polyisocyanate composition in the reference example and the comparative reference example are shown below.

(Evaluation 4) Curable polyisocyanate composition and acrylic polyol (Setalux 1152, manufactured by Nuplex Resins, hydroxyl value 70.4 mgKOH / g (as is), solid content 61% by mass) to NCO / OH = 1.0. The coating composition was prepared by diluting with butyl acetate to a solid content of 50%.
The obtained coating composition was coated on a PP plate with 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) Visually check the transparency of the coating composition prepared by the same method as in the evaluation of curability after coating the glass plate with an applicator so that the film thickness is 80 μm. confirmed.
<Evaluation criteria>
○: No white turbidity ×: White turbidity

(Evaluation 6) Storage stability at low temperature The appearance of the polyisocyanate composition when stored at -10 ° C was observed.
<Evaluation criteria>
◯: No white turbidity after storage for 1 week Δ: No white turbidity after storage for 3 days ×: White turbidity after storage for 1 week ×: White turbidity after storage for 3 days

[Reference Examples 1 to 9, Comparative Reference Examples 1 to 4]
The block polyisocyanate compositions A to M obtained in Synthesis Examples 2 to 14 were used to evaluate curability, compatibility, and storage stability at low temperature. The results obtained are shown in Table 3.

(Synthesis Example 15) A four-necked flask equipped with a polyisocyanate stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube and a dropping funnel is provided with a nitrogen atmosphere, 1000 g of HDI is charged, and the temperature inside the reactor is set to 60 ° C. under stirring. Retained. Then, 2.1 g of tetramethylammonium acetate (2-butanol 5.0% by mass solution) was added as an isocyanurate-forming reaction catalyst to carry out the reaction. After 4 hours, the end point of the reaction was confirmed by measuring the refractive index of the reaction solution, and 0.2 g of phosphoric acid (85% by 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) Block Polyisocyanate Composition N
The inside of a four-necked flask equipped with a stirrer, a thermometer, and a nitrogen blowing tube was made into 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 charged. A mixture of 28.9 parts of ethyl acetoacetate and 0.8 parts of a 28% sodium methylate solution was added at room temperature, and the reaction was continued at 80 ° C. for 2 hours. Then, 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 blocked 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 blocked polyisocyanate composition N.

(Reference Example 11) Block 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. Then, 76.0 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 3 hours while flowing nitrogen. A blocked 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 blocked polyisocyanate composition O.

(Reference Example 12) Block 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, and 0.8 parts of a 28% sodium methylate solution. The mixture was added at room temperature and the reaction was continued at 80 ° C. for 2 hours. Then, 75.3 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 3 hours while flowing nitrogen. A blocked 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 blocked polyisocyanate composition P.

(Reference Example 13) Block 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. Then, 76.0 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 1 hour while flowing nitrogen. A blocked 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 blocked polyisocyanate composition Q.

(Reference Example 14) Block 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 malonic acid, 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. Then, 82.2 parts of isobutanol was added, and the mixture was stirred at 80 ° C. for 3 hours while flowing nitrogen. A blocked polyisocyanate composition R having a resin content of 60% was obtained. Table 4 shows the effective NCO group content and the molar ratio M of the obtained blocked 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 malonic acid, 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. Then, 82.2 parts of isobutanol was added, and the mixture was stirred at 50 ° C. for 2 hours under a nitrogen atmosphere (no flow). A blocked 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 blocked polyisocyanate composition S.

(Comparative Reference Example 6) Block Polyisocyanate Composition T
The inside of a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a dropping funnel was made into a nitrogen atmosphere, and 100 parts of the polyisocyanate obtained in Synthesis Example 15 and 42.3 parts of butyl acetate were charged to prepare malonate. A mixture of 71.1 parts of diethyl, 14.5 parts of ethyl acetoacetate and 0.8 parts of a 28% sodium methylate solution was added at room temperature, and the reaction was continued at 80 ° C. for 2 hours. Then, 76.0 parts of 1-butanol was added, and the mixture was stirred at 80 ° C. for 1 hour under a nitrogen atmosphere (no flow). A blocked polyisocyanate composition T having a resin content of 60% was obtained. Table 4 shows the effective NCO group content and the molar ratio M of the obtained blocked 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 malonic acid, and 0.8 part of a 28% sodium methylate solution. The mixture was added at room temperature and the reaction was continued at 80 ° C. for 2 hours. Then 89.7 parts of 1-butanol was added. A blocked 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 blocked polyisocyanate U.

(Evaluation 7) Curability The block polyisocyanate compositions N to U obtained in Reference Examples 10 to 14 and Comparative Reference Examples 5 to 7 and Setalux 1152 (acrylic polyol, manufactured by Nuplex Resins, hydroxyl value 70.4 mgKOH / g) ( (As is), solid content 51% by mass) was blended so that NCO / OH = 1.0, and diluted with butyl acetate to a solid content of 50%. The obtained coating composition was coated on a PP plate with an applicator so that the resin film thickness was 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 transparency of the coating composition adjusted by the same method as curability was visually confirmed after coating the glass plate with an applicator so that the resin film thickness was 80 μm. Compatibility was evaluated according to the following evaluation criteria.
(Evaluation criteria)
○: No white turbidity ×: White turbidity

(Evaluation 9) Storage stability (Evaluation 7) The viscosity of the coating composition prepared by the same method as the curability was measured by the same method as (Physical characteristics 2) before and after storage at 50 ° C. for 1 week, and the following was performed. Storage stability was evaluated according to the evaluation criteria.
(Evaluation criteria)
◯: Less than 10 times the initial value Δ: 10 times or more and less than 30 times the initial value ×: 30 times or more the initial value

With respect to 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, and (evaluation 9) storage stability. The results of each evaluation are shown in Table 4.

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

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

Further, since the blocked polyisocyanate composition according to the present invention contains a specific binding group in the blocking agent in a specific ratio, it is excellent in low temperature curability, compatibility, and storage stability at low temperature. Therefore, it exhibits excellent performance as a paint, an adhesive, an adhesive, an ink, a sealing agent, a casting agent, a sealing agent, a surface modifier, a coating agent, and the like. Further, since it contains a specific terminal alkyl group generated by the blocking agent in a specific ratio, it is excellent in low temperature curability, storage stability, and compatibility. Therefore, it exhibits excellent performance as a paint, an adhesive, an adhesive, an ink, a sealing agent, a casting agent, a sealing agent, a surface modifier, a coating agent, and the like.

Claims (9)

It contains a polyisocyanate derived from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, a blocking agent, a blocked polyisocyanate obtained from the blocking agent, and a monohydric alcohol compound .
The blocking agent contains 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 malonic acid diester compound to the β-ketoester compound is more than 1.0 and 50 or less.
The content of the monohydric alcohol compound is 10 equivalent% or more and 500 equivalent% or less with respect to the isocyanate group blocked by the blocking agent.
The molar ratio of the total molar ratio of the keto-enol structure represented by the following formula (III) and the keto-enol structure represented by the following formula (IV) to the total of the enol body structure represented by the following formula (V) and the enol body structure represented by the following formula (VI). However, the blocked polyisocyanate composition is 80/20 or more and 97/3 or less.

(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 blocked polyisocyanate composition according to claim 1, wherein the total molar ratio of the keto-enol structure to the enol structure is 80/20 or more and 96/4 or less. Lee isocyanate - ratio of methane tetracarbonyl structure represented by the following formula (VII) to the total amount of malonic acid diester bond structure is 10 mol% or less than 0.5 mol%, block copolyether of claim 1 or 2 Isocyanate composition.

(In the above formula (VII), R ₁ and R ₂ each independently represent an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group, a phenyl group, and a benzyl group.) When the number of moles of the following three bonds contained before Symbol blocked polyisocyanates each with (a) ~ (c), (a) / ((a) + (b) + (c)) = 0. The blocked polyisocyanate composition according to any one of claims 1 to 3, which is 0020 or more and 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 Before Symbol blocked polyisocyanate composition, an isocyanate group is blocked by enol form of the malonic acid diester compound structure and represented by the above formula (V), comprising at least a blocked isocyanate structure,
In the blocked polyisocyanate composition, the molar ratio of the blocked isocyanate structure to which the total amount of the blocked isocyanate structure is such that _{at least one of R 1} and R ₂ in the formula (V) exhibits an alkyl group having 4 or more and 8 or less carbon atoms. , 0.50 or more and less than 0.95, the blocked polyisocyanate composition according to any one of claims 1 to 4. The malonic acid diester compound is diethyl malonate and
The blocked polyisocyanate composition according to any one of claims 1 to 5 , wherein the β-ketoester compound is ethyl acetoacetate. A one-component coating composition comprising the block polyisocyanate composition according to any one of claims 1 to 6 and a polyol. A coating film formed by the one-component coating composition according to claim 7. A painted article coated with the one-component coating composition according to claim 7.