JP5562267B2 - Block polyisocyanate composition and coating composition containing the same - Google Patents

Description

  The present invention relates to a block polyisocyanate composition capable of forming a crosslinked coating film at a temperature of 100 ° C. or less, excellent in moisture stability, and having good curability after storage, and a coating composition using the same. .

  The block polyisocyanate composition is widely used for baking coating as a heat-crosslinking type curing agent together with a melamine curing agent. In recent years, it has been pointed out that formalin is generated when a melamine-based curing agent is used, and block polyisocyanate compositions are attracting attention from the viewpoints of the global environment, safety, hygiene, and the like. Conventionally, oximes, phenols, alcohols, and lactams are known as blocking agents for block polyisocyanate compositions. However, since the block polyisocyanate composition formed using the conventional blocking agent generally requires a high baking temperature of 140 ° C. or higher, the energy cost is very high. Moreover, there has been a restriction that a block polyisocyanate composition that requires high-temperature baking cannot be used for processing into a plastic having low heat resistance.

  In order to overcome such drawbacks, pyrazole block polyisocyanate compositions (Patent Document 1), aliphatic secondary amine block polyisocyanate compositions are used as block polyisocyanate compositions that form a crosslinked coating film at a relatively low temperature. (Patent Document 2) has been proposed. However, these block polyisocyanate compositions require a baking temperature of about 120 ° C., and further reduction in the baking temperature has been desired.

Block polyisocyanate compositions that can be further reduced in baking temperature include co-block polyisocyanate compositions containing (α) diisopropylamine, (β) active methylene compounds, and (γ) oximes as blocking agents (Patent Documents) 3) Block polyisocyanate composition using malonic acid diester as blocking agent (Patent Document 4), Block polyisocyanate composition using diethyl malonate and ethyl acetoacetate as blocking agents (Patent Document 5), isobutanoyl acetate ester A block polyisocyanate composition (Patent Document 6) and the like that are used as blocking agents have been proposed.
Patent Document 7 describes an addition product in which a CH-active alkyl ester or a CH-active alkyl ester is added to an isocyanate as one of raw materials for a synthetic intermediate of an amino group-containing curing component. .

EP159117B1 publication EP96210A1 publication EP600314A1 publication JP 57-121065 A JP-A-8-225630 JP 2009-155408 A JP-A 63-265916

However, in Patent Document 3, the baking temperature is not sufficiently lowered. When the block polyisocyanate compositions of Patent Documents 4 and 5 absorb moisture, carbon dioxide gas is generated, which may cause swelling of the can. Moreover, in patent document 6, the gel fraction after storage may fall.
The present invention has been made in view of the above circumstances, a block polyisocyanate composition capable of forming a crosslinked coating film at a temperature of 100 ° C. or less, excellent in moisture stability, and having good curability after storage. It is an object to provide a product and a coating composition using the product.

  As a result of diligent research, the present inventors have surprisingly found that a composition containing at least one block polyisocyanate having a specific structure retains low-temperature curability and has excellent moisture stability and curability after storage. As a result, the present invention has been completed.

（式中、Ｒは、脂肪族ポリイソシアネート、脂環族ポリイソシアネート、及び芳香族ポリイソシアネートから選ばれる１種又は２種以上から形成されたポリイソシアネートのイソシアネート基を除く残基であり、Ａは、以下の式（ＩＩ）に示される１種又は２種以上のケト体あるいはそのエノール異性体群であり、Ｂは、式（ＩＩＩ）に示される１種又は２種以上の構造単位であり、ｘとｙの合計が２．０〜２０であり、かつｘは０ではない。）

（式中、Ｒ_１は、炭素数１〜８個のアルキル基、フェニル基またはベンジル基を示し、Ｒ_３、Ｒ_４は、同じでも異なっていてもよく、炭素数１〜３０個の、任意にエーテル結合、エステル結合、水酸基、カルボニル基、及びチオール基から選ばれる少なくとも一種を含んでもよい炭化水素基であり、任意にＲ_３、Ｒ_４は、一緒になって５員または６員のシクロアルキル基を形成するか、またはＲ_３とＲ_４に挟まれた窒素原子と一緒になって、架橋員として付加的に窒素または酸素原子を含んでもよい３員、４員、５員または６員環を形成することができる。）

（式中、Ｒ_５は、活性水素含有化合物の活性水素を除く残基である。）
２． 式（Ｉ）におけるｘ、ｙがｘ／ｙ≧１となることを特徴とする、上記１記載のブロックポリイソシアネート組成物。
３． 式（Ｉ）におけるＲが、脂肪族ジイソシアネート及び脂環族ジイソシアネートから選ばれる１種又は２種以上から形成されたポリイソシアネートのイソシアネート基を除く残基である、上記１又は２に記載のブロックポリイソシアネート組成物。
４． 式（ＩＩ）のＲ_１が炭素数１〜４個のアルキル基であることを特徴とする上記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。
５． 式（ＩＩ）のＲ_３、Ｒ_４がともに炭素数３〜６個の分岐アルキル基であることを特徴とする、上記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． 式（ＩＩ）の（Ｒ_３）（Ｒ_４）Ｎ−が式（ＩＶ）で示される連結構造であることを特徴とする上記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。

（式中、Ｒ_６、Ｒ_７、Ｒ_８、Ｒ_９は、各々独立して水素あるいはメチル基を示し、かつ、そのうち少なくとも１つはメチル基である。）
７． 式（ＩＩ）のＲ_３、Ｒ_４がともにイソプロピル基であることを特徴とする、上記５に記載のブロックポリイソシアネート組成物。
８． 式（Ｉ）におけるｘ、ｙがｘ／ｙ≧２であり、かつ、式（ＩＩＩ）におけるＲ_５がマロン酸ジエステル化合物の活性水素を除く残基であることを特徴とする、上記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． 酸解離定数（ＰＫａ）が７．０〜８．５である塩基性化合物（ｅ）を、上記ブロックポリイソシアネート組成物のブロックイソシアネート基に対して１０モル％以上含有し、ここで、ブロックイソシアネート基のモル数は、前駆体であるポリイソシアネート由来のイソシアネート基を基準としたモル数を示す、上記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。
１０． 上記１〜９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、及びポリオールを含む塗料組成物。
１１． 上記１０に記載の塗料組成物からなる塗膜。 That is, the present invention has the following configuration.
1. A block polyisocyanate composition comprising at least one block polyisocyanate represented by the following formula (I):

(In the formula, R is a residue excluding an isocyanate group of a polyisocyanate formed from one or more selected from aliphatic polyisocyanate, alicyclic polyisocyanate, and aromatic polyisocyanate, and A is , One or more keto isomers represented by the following formula (II) or enol isomers thereof, and B is one or more structural units represented by the formula (III), (The sum of x and y is 2.0 to 20, and x is not 0.)

(In the formula, R ₁ represents an alkyl group having 1 to 8 carbon atoms, a phenyl group or a benzyl group, and R ₃ and R ₄ may be the same or different, and may be any one having 1 to 30 carbon atoms. Is a hydrocarbon group that may contain at least one selected from an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol group, and R ₃ and R ₄ are optionally combined together to form a 5-membered or 6-membered cyclohexane. 3-membered, 4-membered, 5-membered or 6-membered which may form an alkyl group or may contain an additional nitrogen or oxygen atom as a bridging member together with a nitrogen atom sandwiched between R ₃ and R ₄ A ring can be formed.)

(In the formula, R ₅ is a residue excluding active hydrogen of the active hydrogen-containing compound.)
2. 2. The block polyisocyanate composition as described in 1 above, wherein x and y in formula (I) satisfy x / y ≧ 1.
3. The block poly described in 1 or 2 above, wherein R in the formula (I) is a residue excluding an isocyanate group of a polyisocyanate formed from one or more selected from aliphatic diisocyanates and alicyclic diisocyanates. Isocyanate composition.
4). The block polyisocyanate composition according to any one of the above 1 to 3, wherein R _{1 in the} formula (II) is an alkyl group having 1 to 4 carbon atoms.
5. The block polyisocyanate composition according to any one of the above 1 to ₄ , wherein R ₃ and R _{4 in} the formula (II) are both branched alkyl groups having 3 to 6 carbon atoms.
6). 5. The block polyisocyanate composition as described in any one of 1 to 4 above, wherein (R ₃ ) (R ₄ ) N— in formula (II) is a linked structure represented by formula (IV).

(In the formula, R ₆ , R ₇ , R ₈ and R ₉ each independently represent hydrogen or a methyl group, and at least one of them is a methyl group.)
7). 6. The block polyisocyanate composition according to 5 above, wherein R ₃ and R _{4 in} formula (II) are both isopropyl groups.
8). 1 to 7 above, wherein x and y in the formula (I) are x / y ≧ 2, and R ₅ in the formula (III) is a residue excluding active hydrogen of the malonic acid diester compound. The block polyisocyanate composition according to any one of the above.
9. The basic compound (e) having an acid dissociation constant (PKa) of 7.0 to 8.5 is contained in an amount of 10 mol% or more based on the blocked isocyanate group of the blocked polyisocyanate composition. The block polyisocyanate composition according to any one of 1 to 8 above, which indicates the number of moles based on an isocyanate group derived from a polyisocyanate that is a precursor.
10. The coating composition containing the block polyisocyanate composition in any one of said 1-9, and a polyol.
11. 11. A coating film comprising the coating composition as described in 10 above.

  According to the present invention, a blocked polyisocyanate composition capable of forming a crosslinked coating film at a temperature of 100 ° C. or less and excellent in moisture stability and curability after storage, a coating composition containing the same, and a coating composition thereof The coating film which consists of a thing can be provided.

式中、Ｒは、脂肪族ポリイソシアネート、脂環族ポリイソシアネート、及び芳香族ポリイソシアネートから選ばれる１種又は２種以上から形成されたポリイソシアネートのイソシアネート基を除く残基である。 Hereinafter, the present invention will be described in detail with a focus on preferred embodiments.
The block polyisocyanate contained in the block polyisocyanate composition of the present invention is represented by the following formula (I).

In formula, R is a residue except the isocyanate group of the polyisocyanate formed from 1 type, or 2 or more types chosen from aliphatic polyisocyanate, alicyclic polyisocyanate, and aromatic polyisocyanate.

  Examples of the aliphatic polyisocyanate include aliphatic diisocyanate, lysine triisocyanate (hereinafter referred to as LTI), 4-isocyanatomethyl-1,8-octamethylene diisocyanate (trimer triisocyanate: hereinafter referred to as TTI), and bis (2-isocyanate). Natoethyl) 2-isocyanatoglutarate (glutamate triisocyanate: hereinafter referred to as GTI) can be exemplified.

  As the aliphatic diisocyanate used in the aliphatic polyisocyanate, those having 4 to 30 carbon atoms are preferable. For example, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (hereinafter referred to as HDI), 2, 2, 4 -Trimethyl-1,6-diisocyanatohexane, lysine diisocyanate and the like. Of these, HDI is preferred because of its industrial availability. Aliphatic diisocyanates may be used alone or in combination of two or more.

  As the alicyclic polyisocyanate, alicyclic diisocyanates shown below are mainly used. As the alicyclic diisocyanate, those having 8 to 30 carbon atoms are preferable, and isophorone diisocyanate (hereinafter referred to as IPDI), 1,3-bis (isocyanatomethyl) -cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, norbornene. Examples include diisocyanate and hydrogenated xylylene diisocyanate. Of these, IPDI is preferred from the viewpoint of weather resistance and industrial availability. An alicyclic diisocyanate may be used independently and may use 2 or more types together.

  As the aromatic polyisocyanate, aromatic diisocyanates shown below are mainly used. Examples of the aromatic diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, and the like. Aromatic diisocyanates may be used alone or in combination of two or more.

  Among these polyisocyanates, aliphatic polyisocyanates and / or alicyclic polyisocyanates are preferable because of excellent weather resistance. Furthermore, among the aliphatic polyisocyanates, aliphatic diisocyanates are most preferable.

The average number of isocyanate groups in the polyisocyanate formed from one or more selected from these polyisocyanates is preferably 2.0 to 20. Furthermore, the lower limit is preferably 2.3, more preferably 2.5, and most preferably 3.0. The upper limit is more preferably 15, and more preferably 10. When the average number of isocyanate groups is 2.0 or more, the crosslinkability is improved and the desired coating film properties can be obtained. On the other hand, when the average number of isocyanate groups is 20 or less, the cohesive force is prevented from becoming too high, and a smooth coating film can be obtained.
The average number of isocyanate groups is determined by the following formula.

  Examples of polyisocyanates that are the source of R in formula (I) include triisocyanates such as LTI, TTI, GTI, and derivatives thereof, as well as biuret bonds, urea bonds, isocyanurate bonds, uretdione bonds, urethanes. Examples include oligomers of diisocyanates produced by forming bonds, allophanate bonds, oxadiazinetrione bonds, and the like. A polyisocyanate having a biuret bond is obtained by reacting a so-called biuretizing agent such as water, t-butanol or urea with a diisocyanate at a molar ratio of biuretizing agent / isocyanate group of the diisocyanate of about 1/2 to about 1/100. Thereafter, unreacted diisocyanate can be removed and purified. A polyisocyanate having an isocyanurate bond is obtained by, for example, carrying out a cyclic trimerization reaction with a catalyst or the like, stopping the reaction when the conversion rate is about 5 to about 80% by mass, and removing and purifying unreacted diisocyanate. . In this case, 1 to 6 valent alcohol compounds can be used in combination.

As the catalyst for the isocyanuration reaction, those having basicity are generally preferred. Examples of such catalysts include
(1) Tetraalkylammonium hydroxide such as tetramethylammonium, tetraethylammonium, and trimethylbenzylammonium, and weak organic acid salts such as acetic acid and capric acid,
(2) Hydroxyalkylammonium hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium and triethylhydroxyethylammonium, and weak organic acid salts such as acetic acid and capric acid,
(3) alkyl metal salts of alkyl carboxylic acids such as tin, zinc, lead and the like,
(4) Metal alcoholates such as sodium and potassium,
(5) Aminosilyl group-containing compound such as hexamethyldisilazane,
(6) Mannich bases,
(7) Combined use of tertiary amines and epoxy compounds,
(8) Phosphorus compounds such as tributylphosphine and the like may be mentioned, and two or more may be used in combination.

  When the reaction catalyst used may adversely affect the properties of the paint or coating film, it is preferable to neutralize the catalyst with an acidic compound or the like. Examples of acidic compounds in this case include inorganic acids such as hydrochloric acid, phosphorous acid, and phosphoric acid, and sulfonic acids such as methanesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid methyl ester, and p-toluenesulfonic acid ethyl ester. Or its derivatives, 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, tetracosyl acid phosphate , Ethyl glycol acid phosphate, butyl pyrophosphate, butyl phosphite, etc., and two or more of them may be used in combination.

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

  Derivatives of LTI, TTI and GTI are also produced in the same manner as polyisocyanates derived from diisocyanates. In the case of these triisocyanates, removal and purification of unreacted triisocyanates is not always necessary.

式（ＩＩ）は、ケト体を示しているが、ケト−エノール互変異性体であるエノール体群も含む。例えば、メチン基のプロトンがアミド基側でエノール体となった構造や、エステル基側でエノール体となった構造も含む。この場合のケト体の組成比は、５０％以上であることが好ましく、更に好ましくは７５％以上であり、より好ましくは９０％以上である。 A in the formula (I) is one or more keto bodies represented by the following formula (II) or a group of enol bodies thereof.

Formula (II) shows a keto form, but also includes an enol group that is a keto-enol tautomer. For example, a structure in which the proton of the methine group becomes an enol body on the amide group side and a structure in which the proton on the amide group side becomes an enol body are included. In this case, the composition ratio of the keto body is preferably 50% or more, more preferably 75% or more, and more preferably 90% or more.

R ₁ in formula (II) represents an alkyl group having 1 to 8 carbon atoms, a phenyl group or a benzyl group. When R ₁ is an alkyl group having 9 or more carbon atoms, the effective NCO% is lowered, and compatibility with the main agent and the like when used as a paint may be lowered, which is not preferable. Among these, R ₁ is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, still more preferably a methyl group or an ethyl group, and most preferably An ethyl group.

R ₃ and R ₄ in the formula (II) may be the same or different, and have at least one selected from an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol group having 1 to 30 carbon atoms. Optionally R ₃ and R ₄ together form a 5- or 6-membered cycloalkyl group or together with a nitrogen atom sandwiched between R ₃ and R ₄ Thus, a 3-membered, 4-membered, 5-membered or 6-membered ring which may additionally contain a nitrogen or oxygen atom as a bridging member can be formed. Among them, R ₃ and R ₄ may be the same or different, and may contain 1 to 30 carbon atoms and optionally include at least one selected from an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol group. 3-membered, 4-membered, 5-membered or 6-membered which may be a good hydrocarbon group or may contain an additional nitrogen or oxygen atom as a bridging member together with a nitrogen atom sandwiched between R ₃ and R ₄ It is preferable that it can form a ring.

Here, R ₃ and R ₄ in formula (II) are divided into a structure that exists independently (hereinafter referred to as an independent structure) and a structure that is connected (hereinafter referred to as a connected structure). To do.

First, the independent structure of R ₃ and R ₄ will be described.
R ₃ and R _{4 in} formula (II) in the case of an independent structure may be the same or different, and optionally have 1 to 30 carbon atoms, an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol group It is a hydrocarbon group which may contain at least one selected from Among them, R _3, R ₄ is preferably a 1-8C hydrocarbon group atoms, and more preferably, preferably a branched alkyl group having 3 to 6 carbon atoms, more preferably, carbon A branched alkyl group having a number of 3 to 4, and most preferably an isopropyl group. Preferable substituents that R ₃ and R ₄ may contain include an ether bond and an ester bond. When R ₃ and R ₄ are alkyl groups having 30 or less carbon atoms, a decrease in effective NCO% can be suppressed and compatibility with the main agent and the like when used as a paint can be kept high.

Next, the connection structure of R ₃ and R ₄ will be described.
The (R ₃ ) (R ₄ ) N- moiety in the formula (II) in the case of a linking structure is a residue excluding the active hydrogen of a cyclic secondary amine containing a nitrogen atom shown below. Specific cyclic secondary amines include 2-azabicyclo [2.1.1] hexane, azabicyclo compounds such as 7-azabicyclo [2.2.1] heptane, aziridine, azetidine, pyrrolidine, and 2-methylpyrrolidine. 3-pyrrolidol, 2-pyrrolidone, proline, 4-hydroxyproline, piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 4-benzylpiperidine, 2,4-dimethylpiperidine, 3,5- Dimethylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, 3-piperidinemethanol, 2-piperidineethanol, 4-piperidineethanol, 4-piperidinol, 2-piperidone, 4-piperidone, 4 -Piperidinecarboxylic acid methyl ester, 4 Piperidinecarboxylic acid ethyl ester, 2,2,6,6-tetramethyl-4-piperidone, 4-piperidinopiperidine, decahydroquinoline, piperazine, N-methylpiperazine, N-ethylpiperazine, N-allylpiperazine, N -Isobutylpiperazine, N-cyclohexylpiperazine, N-cyclopentylpiperazine, N-phenylpiperazine, 1- (2-pyridyl) piperazine, 1- (4-pyridyl) piperazine, 1- (2-pyrimidyl) piperazine, N-methylhomo Piperazine, N-acetylhomopiperazine, N-butyrylhomopiperazine, oxazolidine, morpholine, imidazolidine, 2-imidazolidone, hydantoin, 1-methylhydantoin, 5-methylhydantoin, creatinine, paravanic acid, urazole, thia Saturated cyclic secondary amines such as lysine and thiardine, pyrrole, 2-methylpyrrole, 2,4-dimethylpyrrole, 3,4-dimethylpyrrole, 2-acetylpyrrole, 2-pyrrolecarboxylic acid, indole, 3H-indole, 3-methylindole, 2-phenylindole, 3-hydroxylindole, 3-indoleacetic acid, indoline, 2-indolinone, isatin, α-cisatin oxime, isoindole, isoindoline, 1-isoindolinone, carbazole, 1,2, 3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline, 9-acridone, pyrazole, 3,5-dimethylpyrazole, imidazole, benzimidazole, benzimidazolone, 1H-1,2,3-triazole, 1H-1,2,4 Aromatic secondary amines such as triazole, benzotriazole, tetrazole, purine, xanthine, phenoxazine, isatoic anhydride, benzothiazoline, 2-benzothiazolone, phenothiazine, 5,10-dihydrophenazine, β-carboline, perimidine, 2- Such as pyrroline, 3-pyrroline, dihydropyridine, 2-pyrazoline, 5-pyrazolone, 2-imidazoline, 4H-1,4-oxazine, 4H-1,4-thiazine, 2H, 6H-1,5,2-dithiazine And unsaturated bond-containing cyclic secondary amines.

  Among these cyclic secondary amines, aziridine, azetidine, pyrrolidine, 2-methylpyrrolidine, 3-pyrroldiol, 2-pyrrolidone, proline, 4-hydroxyproline, piperidine, 2-methylpiperidine, 3-methylpiperidine, 4- Methylpiperidine, 4-benzylpiperidine, 2,4-dimethylpiperidine, 3,5-dimethylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, 3-piperidinemethanol, 2-piperidineethanol 4-piperidineethanol, 4-piperidinol, 2-piperidone, 4-piperidone, 4-piperidinecarboxylic acid methyl ester, 4-piperidinecarboxylic acid ethyl ester, 2,2,6,6-tetramethyl-4-piperidone, 4, -Piperidinopiperidine Decahydroquinoline, piperazine, N-methylpiperazine, N-ethylpiperazine, N-allylpiperazine, N-isobutylpiperazine, N-cyclohexylpiperazine, N-cyclopentylpiperazine, N-phenylpiperazine, 1- (2-pyridyl) piperazine, 1- (4-pyridyl) piperazine, 1- (2-pyrimidyl) piperazine, N-methylhomopiperazine, N-acetylhomopiperazine, N-butyrylhomopiperazine, oxazolidine, morpholine, imidazolidine, 2-imidazolidone, hydantoin, 1-methylhydantoin, 5-methylhydantoin, creatinine, parabanic acid, urazole, thiazolidine, and thiaridine are preferable.

  More preferably, aziridine, azetidine, pyrrolidine, 2-methylpyrrolidine, piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 4-benzylpiperidine, 2,4-dimethylpiperidine, 3,5-dimethylpiperidine 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, 4-piperidinecarboxylic acid methyl ester, 4-piperidinecarboxylic acid ethyl ester, 2,2,6,6-tetramethyl-4-piperidone 4-piperidinopiperidine, piperazine, N-methylpiperazine, N-ethylpiperazine, N-allylpiperazine, N-isobutylpiperazine, N-cyclohexylpiperazine, N-cyclopentylpiperazine, N-phenylpiperazine, 1- (2- Pyridyl) pipera 1- (4-pyridyl) piperazine, 1- (2-pyrimidyl) piperazine, N-methylhomopiperazine, N-acetylhomopiperazine, N-butyrylhomopiperazine; more preferably pyrrolidine, 2-methyl Pyrrolidine, piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 2,4-dimethylpiperidine, 3,5-dimethylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethyl Most preferred are 2-methylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine.

式（ＩＶ）中、Ｒ_６、Ｒ_７、Ｒ_８、Ｒ_９は、各々独立して水素あるいはメチル基を示し、かつ、そのうち少なくとも１つはメチル基である。
すなわち、上記式（ＩＩ）における窒素原子上のアルキル置換基において、窒素原子と隣接する炭素原子の少なくとも１つが２個以上の炭素原子と結合していることが好ましい。 As shown in the specific examples above, examples of the cyclic secondary amine compound containing a nitrogen atom include saturated cyclic secondary amines, aromatic secondary amines, and unsaturated bond-containing cyclic secondary amines. Secondary amines are preferred. Of the saturated cyclic secondary amines, secondary amines containing only one nitrogen atom are preferable, more preferably 5-membered or 6-membered rings, and still more preferably a structure represented by the following formula (IV). In addition, a piperidine derivative in which the substituents at the 2 and 6 positions are hydrogen or a methyl group, and at least one of them is a methyl group. Specific examples of the compound name include 2-methylpiperidine, 2,6-dimethylpiperidine, and 2,2,6,6-tetramethylpiperidine.

In formula (IV), R ₆ , R ₇ , R ₈ and R ₉ each independently represent hydrogen or a methyl group, and at least one of them is a methyl group.
That is, in the alkyl substituent on the nitrogen atom in the formula (II), at least one of the carbon atoms adjacent to the nitrogen atom is preferably bonded to two or more carbon atoms.

  The block polyisocyanate composition of the present invention may partially contain a block polyisocyanate having a keto body represented by the following formula (VI) or an enol body group thereof as an alternative to A in the formula (I).

(Wherein, R _3, R _4, which may be the same or different, 1 to 30 carbon atoms, optionally an ether bond, an ester bond, a hydroxyl group, contain at least one selected from a carbonyl group and a thiol group, Optionally R ₃ , R ₄ together form a 5- or 6-membered cycloalkyl group, or together with a nitrogen atom sandwiched between R ₃ and R ₄ Thus, a 3-membered, 4-membered, 5-membered or 6-membered ring which may additionally contain a nitrogen or oxygen atom as a bridging member can be formed.
R ₁₁ and R ₁₂ may be the same or different and may contain hydrogen or at least one selected from an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol group having 1 to 30 carbon atoms. A good hydrocarbon group, optionally R ₁₁ and R ₁₂ together form a 5- or 6-membered cycloalkyl group or together with a nitrogen atom sandwiched between R ₁₁ and R ₁₂ A 3-membered, 4-membered, 5-membered or 6-membered ring which may additionally contain a nitrogen or oxygen atom as a bridging member. )
The content of the block polyisocyanate represented by the formula (VI) in A in the formula (I) is preferably 50% by mass or less from the viewpoint of suppressing crystallization while maintaining low temperature curability, Preferably it is 30 mass% or less, More preferably, it is 20 mass% or less, Most preferably, it is 10 mass% or less.

式（ＩＩＩ）におけるＲ_５は、活性水素含有化合物の活性水素を除く残基である。 B in the formula (I) is one or more structural units represented by the following formula (III).

R ₅ in the formula (III) is a residue excluding active hydrogen of the active hydrogen-containing compound.

The active hydrogen-containing compound that is a source of R ₅ in formula (III) is not particularly limited as long as it is an active hydrogen-containing compound that can react with an isocyanate group. As the active hydrogen-containing compound to be used, those generally known as blocking agents are preferable. As the blocking agent, a compound having one active hydrogen in the molecule is preferable. For example, an alcohol, alkylphenol, phenol, active methylene, mercaptan, acid amide, acid imide, imidazole, urea, There are oxime, amine, imide, and pyrazole compounds.

Examples of more specific blocking agents are shown below.
(1) aliphatic alcohols such as methanol, ethanol, 2-propanol, n-butanol, sec-butanol, 2-ethyl-1-hexanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol,
(2) alkylphenol-based mono- and dialkylphenols having an alkyl group having 4 or more carbon atoms as a substituent, such as n-propylphenol, i-propylphenol, n-butylphenol, sec-butylphenol, t-butylphenol , N-hexylphenol, 2-ethylhexylphenol, n-octylphenol, n-nonylphenol and other monoalkylphenols, di-n-propylphenol, diisopropylphenol, isopropylcresol, di-n-butylphenol, di-t-butylphenol, di- Dialkylphenols such as -sec-butylphenol, di-n-octylphenol, di-2-ethylhexylphenol, di-n-nonylphenol,
(3) phenolic; phenol, cresol, ethylphenol, styrenated phenol, hydroxybenzoic acid ester, etc.

(4) Active methylene type; dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, etc.
(5) Mercaptan series; butyl mercaptan, dodecyl mercaptan, etc.
(6) Acid amide system: acetanilide, acetic acid amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam, etc.
(7) Acid imide type; succinimide, maleic imide, etc.
(8) Imidazole series; imidazole, 2-methylimidazole, etc.
(9) Urea system; urea, thiourea, ethylene urea, etc.
(10) Oxime type: formaldoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, cyclohexanone oxime, etc.
(11) Amine type; 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.
(12) Imine type; ethyleneimine, polyethyleneimine, etc.
(13) Pyrazole type: pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole and the like.

  The preferred active hydrogen-containing compound is at least one selected from alcohol-based, oxime-based, amine-based, acid amide-based, active methylene-based, and pyrazole-based blocking agents, and more preferably oxime-based, active methylene-based, pyrazole. And at least one selected from active methylene-based blocking agents. Most preferred is malonic acid diester.

  As the active hydrogen of the active hydrogen-containing compound, if it is an alcohol, it is a hydrogen of a hydroxyl group, and if it is an active methylene, it is a hydrogen of a methylene group sandwiched between two carbonyl groups, and if it is an amine, Illustrative is hydrogen bonded to a nitrogen atom. That is, the residue excluding active hydrogen of the active hydrogen-containing compound refers to a residue obtained by removing each active hydrogen from an active hydrogen-containing compound such as alcohol, active methylene, and amine.

  The sum of x and y in the formula (I) of the present invention is a value corresponding to the average number of isocyanate groups of the polyisocyanate that is the source of R, is 2.0 to 20, and x is not 0. y may be 0, but is more preferably not 0. The lower limit of the sum of x and y is preferably 2.3, more preferably 2.5, and most preferably 3.0. The upper limit of the sum of x and y is more preferably 15, and most preferably 10. In addition, x and y here mean the statistical average number with respect to R of A and B, respectively.

  When the total of x and y is 2.0 or more, the crosslinkability is improved, and the desired coating film properties can be obtained. On the other hand, when the sum of x and y is 20 or less, the cohesive force is prevented from becoming too high, and a smooth coating film can be obtained. When y is not 0, x and y are preferably x / y ≧ 1, more preferably x / y ≧ 1.5, and further preferably x / y ≧ 2.

  Next, the manufacturing method of the block polyisocyanate composition of this invention is demonstrated. The block polyisocyanate composition can be broadly classified and synthesized by two production methods (hereinafter referred to as “production method 1” and “production method 2”).

  In the production method 1, after reacting the polyisocyanate (a) which is the source of R in the formula (I) with the malonic acid diester (b) represented by the following formula (VII), the following formula (VIII) is obtained. This is a method of reacting the organic amine compound (c) shown.

(In the formula, R ₁ and R ₂ represent an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a benzyl group, and R ₁ and R ₂ may be the same or different.)

(Wherein, R _3, R _4, which may be the same or different, 1 to 30 carbon atoms, optionally an ether bond, an ester bond, a hydroxyl group, contain at least one selected from a carbonyl group and a thiol group, Optionally R ₃ , R ₄ together form a 5- or 6-membered cycloalkyl group and together with a nitrogen atom sandwiched between R ₃ and R ₄ Thus, a 3-membered, 4-membered, 5-membered or 6-membered ring which may additionally contain a nitrogen or oxygen atom as a bridging member can be formed.)

  Production method 2 is a method in which a polyisocyanate serving as a source of R in formula (I) is reacted with a compound represented by the following formula (IX).

(In the formula, R ₁ represents an alkyl group having 1 to 8 carbon atoms, a phenyl group or a benzyl group, and R ₃ and R ₄ may be the same or different, and may be any one having 1 to 30 carbon atoms. Is a hydrocarbon group that may contain at least one selected from an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol group, and R ₃ and R ₄ are optionally taken together to form a 5- or 6-membered cycloalkyl 3-membered, 4-membered, 5-membered or 6-membered ring which may form a group or together with a nitrogen atom sandwiched between R ₃ and R ₄ may additionally contain a nitrogen or oxygen atom as a bridging member Can be formed.)

  From the viewpoint of ease of production, production method 1 is more preferable. The production method 1 will be described below.

  Production method 1 includes a polyisocyanate (a) having one or more selected from the group consisting of aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates as a skeleton and a malon represented by formula (VII) The acid diester (b) is preferably added in an amount of 75 to 150 mol% based on the isocyanate group of the polyisocyanate (a), and the isocyanate group of the polyisocyanate (a) is reacted with the malonic acid diester (b); The product obtained in the first step comprises two steps of the second step in which one or more organic amine compounds (c) represented by the formula (VIII) are reacted.

  The first step will be described. The addition amount of the malonic acid diester (b) in the first step of the production method 1 is 75 to 150 mol% with respect to the isocyanate group in the polyisocyanate (a) which is the source of R in the formula (I). preferable. As a lower limit, 90 mol% is more preferable, More preferably, it is 95 mol%, Most preferably, it is 100 mol%. As an upper limit, 130 mol% is more preferable, More preferably, it is 120 mol%, Most preferably, it is 110 mol%. When the addition amount is 75 mol% or more, deterioration of low-temperature curability can be prevented. Moreover, when the addition amount is 150 mol% or less, it is possible to suppress adverse effects on coating film properties such as water resistance of the baked coating film.

Malonic acid diester (b) in the first step of production method 1 is represented by formula (VII). Specifically, R ₁ and R ₂ are an alkyl group having 1 to 8 carbon atoms, a phenyl group, or a benzyl group. R ₁ and R ₂ may be the same or different, but it is preferable that R ₁ = R ₂ because of availability. When R ₁ and R ₂ are alkyl groups having 8 or less carbon atoms, it is possible to suppress a decrease in effective NCO% and to prevent deterioration of compatibility with the main agent and the like when used as a paint. Among these, it is preferable that it is a C1-C8 alkyl group, More preferably, it is a C1-C4 alkyl group, More preferably, it is a methyl group or an ethyl group, Most preferably, it is an ethyl group. is there. Here, the effective NCO mass% is the mass% of isocyanate groups potentially present with respect to the total mass of the blocked polyisocyanate composition.

  Specific examples of the malonic acid diester (b) include dimethyl malonate, diethyl malonate, di-n-propyl malonate, diisopropyl malonate, di-n-butyl malonate, diisobutyl malonate, di-t-butyl malonate, and malon. Examples thereof include methyl t-butyl ester, di-n-hexyl malonate, di-2-ethylhexyl malonate, diphenyl malonate, and dibenzyl malonate. Among them, dimethyl malonate, diethyl malonate, di-n-propyl malonate, diisopropyl malonate, di-n-butyl malonate, diisobutyl malonate, di-t-butyl malonate, methyl t-butyl malonate, malonic acid Di n-hexyl and di-2-ethylhexyl malonate are preferred. More preferably, it is dimethyl malonate, diethyl malonate, di-n-propyl malonate, diisopropyl malonate, di-n-butyl malonate, diisobutyl malonate, di-t-butyl malonate, methyl t-butyl malonate. More preferred are dimethyl malonate and diethyl malonate, and most preferred is diethyl malonate. The malonic acid diester shown above can be used alone or in combination of two or more.

The reaction in the first step can be performed regardless of the presence or absence of a solvent. When using a solvent, it is preferable to use a solvent which is inert to the isocyanate group and hardly hydrolyzes. Preferred solvents are ether solvents such as propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol dimethyl ether and diethylene glycol diethyl ether, and ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone.
For the reaction in the first step, a reaction catalyst can be used. Specific examples of the reaction catalyst include organic metal salts such as tin, zinc and lead, metal alcoholates, and tertiary amines.

  When the reaction catalyst used may adversely affect the properties of the paint or coating film, it is preferable to deactivate the catalyst with an acidic compound or the like. Examples of acidic compounds in this case include inorganic acids such as hydrochloric acid, phosphorous acid, and phosphoric acid, and sulfonic acids such as methanesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid methyl ester, and p-toluenesulfonic acid ethyl ester. Or its derivatives, 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, tetracosyl acid phosphate , Ethyl glycol acid phosphate, butyl pyrophosphate, butyl phosphite and the like. Two or more of these acidic compounds may be used in combination.

  The reaction in the first step can be generally carried out at -20 to 150 ° C, preferably 0 to 100 ° C, more preferably 40 to 80 ° C. By performing the reaction at 150 ° C. or lower, side reactions can be suppressed, and by performing the reaction at −20 ° C. or higher, the reaction rate can be kept high.

  The composition ratio of x and y in the formula (I) depends on the mol% of the malonic acid diester (b) added to the isocyanate group in the polyisocyanate (a) and the reaction rate in the first step. However, when finally mixing the block polyisocyanate composition synthesize | combined in another reaction tank, and making it the block polyisocyanate composition of this invention, it also depends on a mixing ratio. Since the composition ratio of x and y depends not only on the mole% of malonic acid diester (b) added to the isocyanate group in the polyisocyanate (a) in the first step, but also on the reaction rate thereof, before the second step. It is preferable to confirm the isocyanate residual rate at the end of the first step. When the unreacted isocyanate group remains, the organic amine (c) in the second step is obtained from the reaction between the isocyanate group produced in the first step and the ester part of the reaction product of the malonic acid diester (b). Also preferentially react with isocyanate groups. In this invention, since it is preferable that x ratio is high and there are few residual isocyanate groups, it is more preferable to perform a 2nd process, after confirming that the isocyanate group has lose | disappeared in the 1st process.

Next, the 2nd process of the manufacturing method 1 is demonstrated. The addition amount of the organic amine compound (c) represented by the formula (VIII) in the second step is 50 to 500 mol% with respect to the isocyanate group of the polyisocyanate (a) which is a precursor of the block polyisocyanate. preferable. As a lower limit of this addition amount, 70 mol% is more preferable, More preferably, it is 90 mol%. The upper limit of the total addition amount is more preferably 400 mol%, further preferably 300 mol%, and most preferably 200 mol%. When the total addition amount is 50 mol% or more, moisture stability can be kept high, and when it is 500 mol% or less, the amount of free amine is reduced and coloring of the baking coating film is prevented. Can do.
The organic amine (c) used in the second step is added mainly for the reaction between the ester part of the reaction product of the polyisocyanate and the malonic acid diester (b) after the first step. However, when an isocyanate group remains after the first step, the remaining isocyanate group may react with the organic amine (c) used in the second step. In that case, B in the formula (I).
Moreover, when the malonic acid diester (b) with respect to the isocyanate group in the polyisocyanate (a) is added in an amount exceeding 100 mol% in the first step, the malonic acid diester (b) remains after the first step. . In that case, a part of malonic acid monoester monoamide or malonic acid diamide, which is a reaction product of the malonic acid diester (b) remaining after the first step and the organic amine compound (c) added in the second step, is included. It doesn't matter.

The organic amine compound (c) used in the second step is represented by the formula (VIII). Specifically, in the organic amine compound (c) represented by the formula (VIII), R ₃ and R ₄ may be the same or different and optionally have an ether bond or ester bond having 1 to 30 carbon atoms. , A hydrocarbon group that may include at least one selected from a hydroxyl group, a carbonyl group, and a thiol group, and optionally R ₃ and R ₄ together form a 5- or 6-membered cycloalkyl group, Or, together with the nitrogen atom sandwiched between R ₃ and R ₄ , it forms a 3-membered, 4-membered, 5-membered or 6-membered ring which may additionally contain a nitrogen or oxygen atom as a bridging member. . Among these, R ₃ and R ₄ may be the same or different, and contain at least one selected from an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol group having 1 to 30 carbon atoms. A 3-membered, 4-membered, 5-membered or 6-membered hydrocarbon group which may additionally contain a nitrogen or oxygen atom as a bridging member together with a nitrogen atom sandwiched between R ₃ and R ₄ It is preferable to form a member ring.

The organic amine compound (c) is roughly classified into a chain secondary amine compound and a cyclic secondary amine compound containing a nitrogen atom. First, the chain secondary amine compound will be described. R ₃ and R ₄ in the chain secondary amine compound of the formula (VIII) may be the same or different, and optionally having 1 to 30 carbon atoms, an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol It is a hydrocarbon that may contain at least one selected from the group. Among them, it is preferably a hydrocarbon having 1 to 8 carbon atoms, more preferably a branched alkyl group having 3 to 6 carbon atoms, still more preferably a branched alkyl group having 3 to 4 carbon atoms, An isopropyl group is preferred. When R ₃ and R ₄ are alkyl groups having 30 or less carbon atoms, a decrease in effective NCO% can be suppressed and compatibility with the main agent and the like when used as a paint can be kept high.

  Specific examples of the chain secondary amine compound used in the present invention include dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dioctylamine, dilaurylamine, ditridecylamine, and distearylamine. Straight chain secondary amine, diisopropylamine, diisobutylamine, di (2-butylamine), di (t-butyl) amine, di (2-ethylhexyl) amine, dicyclohexylamine, di (2-methylcyclohexyl) amine, etc. Branched secondary amine, secondary amine containing unsaturated double bond such as diallylamine, methylethylamine, N-methylisopropylamine, methyl t-butylamine, N-methylhexylamine, ethyl t-butylamine, N-ethylhexylamine, N -D Such as ru-1,2-dimethylpropylamine, N-ethylisoamylamine, N-ethyllaurylamine, N-ethylstearylamine, N-methylcyclohexylamine, N-ethylcyclohexylamine, Nt-butylcyclohexylamine Asymmetric secondary amine, diphenylamine, dibenzylamine, methylbenzylamine, ethylbenzylamine, t-butylbenzylamine, N-methylaniline, N-ethylaniline, N-cyclohexylaniline, 3- (benzylamino) propionic acid ethyl ester Secondary amines having an aromatic substituent such as 2- (hydroxymethylamino) ethanol, diethanolamine, N-methylethanolamine, 4-methylaminobutanol, N-ethylethanolamine, N-propyl ether Noruamin, N- isopropyl ethanolamine, N- butyl ethanolamine, and the like.

  Among these chain secondary amine compounds, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dioctylamine, diisopropylamine, diisobutylamine, di (2-butylamine), di (t-butyl) ) Amine, di (2-ethylhexyl) amine, dicyclohexylamine, di (2-methylcyclohexyl) amine, diallylamine, methylethylamine, N-methylisopropylamine, methyl t-butylamine, N-methylhexylamine, ethyl t-butylamine, N-ethylhexylamine, N-ethyl-1,2-dimethylpropylamine, N-ethylisoamylamine, N-methylcyclohexylamine, N-ethylcyclohexylamine, Nt-butylcyclohexyl Silamine, diphenylamine, dibenzylamine, methylbenzylamine, ethylbenzylamine, t-butylbenzylamine, N-methylaniline, N-ethylaniline, 2- (hydroxymethylamino) ethanol, diethanolamine, N-methylethanolamine, 4 -Methylaminobutanol, N-ethylethanolamine, N-propylethanolamine, N-isopropylethanolamine, N-butylethanolamine are preferred. More preferred are diisopropylamine, diisobutylamine, di (2-butylamine), di (t-butyl) amine, dicyclohexylamine, Nt-butylcyclohexylamine, and more preferred are diisopropylamine, diisobutylamine, di ( 2-butylamine) and di (t-butyl) amine, and most preferably diisopropylamine.

Next, the cyclic secondary amine compound containing a nitrogen atom will be described. As the cyclic secondary amine compound containing a nitrogen atom, in the formula (VIII), R ₃ and R ₄ together form a 5- or 6-membered cycloalkyl group, or together with the nitrogen atom A 3-membered, 4-membered, 5-membered or 6-membered ring which may additionally contain a nitrogen or oxygen atom as a bridging member.

  Specific examples of the cyclic secondary amine compound containing a nitrogen atom include 2-azabicyclo [2.1.1] hexane, azabicyclo compounds such as 7-azabicyclo [2.2.1] heptane, aziridine, azetidine, and pyrrolidine. 2-methylpyrrolidine, 3-pyrroldiol, 2-pyrrolidone, proline, 4-hydroxyproline, piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 4-benzylpiperidine, 2,4-dimethylpiperidine 3,5-dimethylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, 3-piperidinemethanol, 2-piperidineethanol, 4-piperidineethanol, 4-piperidinol, 2-piperidone, 4-piperidone, 4-piperidinecarboxylic acid Methyl ester, 4-piperidinecarboxylic acid ethyl ester, 2,2,6,6-tetramethyl-4-piperidone, 4-piperidinopiperidine, decahydroquinoline, piperazine, N-methylpiperazine, N-ethylpiperazine, N -Allylpiperazine, N-isobutylpiperazine, N-cyclohexylpiperazine, N-cyclopentylpiperazine, N-phenylpiperazine, 1- (2-pyridyl) piperazine, 1- (4-pyridyl) piperazine, 1- (2-pyrimidyl) piperazine N-methylhomopiperazine, N-acetylhomopiperazine, N-butyrylhomopiperazine, oxazolidine, morpholine, imidazolidine, 2-imidazolidone, hydantoin, 1-methylhydantoin, 5-methylhydantoin, creatinine, paraban , Saturated cyclic secondary amines such as urazole, thiazolidine, thiaridine, pyrrole, 2-methylpyrrole, 2,4-dimethylpyrrole, 3,4-dimethylpyrrole, 2-acetylpyrrole, 2-pyrrolecarboxylic acid, indole, 3H -Indole, 3-methylindole, 2-phenylindole, 3-hydroxylindole, 3-indoleacetic acid, indoline, 2-indolinone, isatin, α-cisatin oxime, isoindole, isoindoline, 1-isoindolinone, carbazole, 1 , 2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline, 9-acridone, pyrazole, 3,5-dimethylpyrazole, imidazole, benzimidazole, benzimidazolone, 1H-1,2,3 -Triazo Like 1H-1,2,4-triazole, benzotriazole, tetrazole, purine, xanthine, phenoxazine, isatoic acid, benzothiazoline, 2-benzothiazolone, phenothiazine, 5,10-dihydrophenazine, β-carboline, perimidine Aromatic secondary amine, 2-pyrroline, 3-pyrroline, dihydropyridine, 2-pyrazoline, 5-pyrazolone, 2-imidazoline, 4H-1,4-oxazine, 4H-1,4-thiazine, 2H, 6H-1 , 5,2-dithiazine-containing unsaturated secondary cyclic amines and the like.

  Among these cyclic secondary amine compounds containing nitrogen atoms, aziridine, azetidine, pyrrolidine, 2-methylpyrrolidine, 3-pyrroldiol, 2-pyrrolidone, proline, 4-hydroxyproline, piperidine, 2-methylpiperidine, 3- Methylpiperidine, 4-methylpiperidine, 4-benzylpiperidine, 2,4-dimethylpiperidine, 3,5-dimethylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, 3-piperidinemethanol 2-piperidineethanol, 4-piperidineethanol, 4-piperidinol, 2-piperidone, 4-piperidone, 4-piperidinecarboxylic acid methyl ester, 4-piperidinecarboxylic acid ethyl ester, 2,2,6,6-tetramethyl- 4-piperidone, 4- Peridinopiperidine, decahydroquinoline, piperazine, N-methylpiperazine, N-ethylpiperazine, N-allylpiperazine, N-isobutylpiperazine, N-cyclohexylpiperazine, N-cyclopentylpiperazine, N-phenylpiperazine, 1- (2- Pyridyl) piperazine, 1- (4-pyridyl) piperazine, 1- (2-pyrimidyl) piperazine, N-methylhomopiperazine, N-acetylhomopiperazine, N-butyrylhomopiperazine, oxazolidine, morpholine, imidazolidine, 2- Imidazolidone, hydantoin, 1-methylhydantoin, 5-methylhydantoin, creatinine, parabanic acid, urazole, thiazolidine and thiardine are preferred.

  Among these, more preferably, aziridine, azetidine, pyrrolidine, 2-methylpyrrolidine, piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 4-benzylpiperidine, 2,4-dimethylpiperidine, 3, 5-dimethylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, 4-piperidinecarboxylic acid methyl ester, 4-piperidinecarboxylic acid ethyl ester, 2,2,6,6-tetramethyl -4-piperidone, 4-piperidinopiperidine, piperazine, N-methylpiperazine, N-ethylpiperazine, N-allylpiperazine, N-isobutylpiperazine, N-cyclohexylpiperazine, N-cyclopentylpiperazine, N-phenylpiperazine, 1 -(2- Lysyl) piperazine, 1- (4-pyridyl) piperazine, 1- (2-pyrimidyl) piperazine, N-methylhomopiperazine, N-acetylhomopiperazine, N-butyrylhomopiperazine; more preferably pyrrolidine, 2 -Methylpyrrolidine, piperidine, 2-methylpiperidine, 3-methylpiperidine, 4-methylpiperidine, 2,4-dimethylpiperidine, 3,5-dimethylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6- Most preferred are 2-methylpiperidine, 2,6-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine.

  Examples of the cyclic secondary amine compound containing a nitrogen atom include saturated cyclic secondary amines, aromatic secondary amines, and unsaturated bond-containing cyclic secondary amines as shown in the specific examples above. Secondary amines are preferred. Among the saturated cyclic secondary amines, secondary amines containing only one nitrogen atom are preferable, more preferably 5-membered or 6-membered rings, and still more preferably 2,6-positions represented by the following formula (X). Are substituents of hydrogen or methyl, and at least one of which is a methyl group. Specific examples of the compound name include 2-methylpiperidine, 2,6-dimethylpiperidine, and 2,2,6,6-tetramethylpiperidine described above.

式（Ｘ）中、Ｒ_６、Ｒ_７、Ｒ_８、Ｒ_９は、各々独立して水素あるいはメチル基を示し、かつ、そのうち少なくとも１つはメチル基である。
すなわち、有機アミン化合物（ｃ）としては、上記式（ＶＩＩＩ）における窒素原子上のアルキル置換基において、窒素原子と隣接する炭素原子の少なくとも１つが２個以上の炭素原子と結合していることが、好ましい。

In formula (X), R ₆ , R ₇ , R ₈ and R ₉ each independently represent hydrogen or a methyl group, and at least one of them is a methyl group.
That is, as the organic amine compound (c), in the alkyl substituent on the nitrogen atom in the above formula (VIII), at least one of the carbon atoms adjacent to the nitrogen atom is bonded to two or more carbon atoms. ,preferable.

  In the 2nd process of the manufacturing method 1, the chain amine compound shown above and the cyclic amine compound containing a nitrogen atom can also be used independently, and it can also be used in combination of 2 or more types. Similarly to the reaction in the first step, the reaction in the second step can be performed regardless of the presence or absence of a solvent. When using a solvent, it is preferable to use a solvent which is inert to the isocyanate group and hardly hydrolyzes. Preferred solvents are ether solvents such as propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, diethylene glycol dimethyl ether and diethylene glycol diethyl ether, and ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone.

In the reaction in the second step of production method 1, the catalyst described above for the first step can also be used. However, when used, the reaction solution may be colored, and it is preferable not to use it. When a catalyst is used in the first step, it is preferable to carry out the second step after deactivation with an acidic compound or the like.
Similarly to the first step, the reaction in the second step can be generally carried out at -20 to 150 ° C, preferably 0 to 100 ° C, more preferably 40 to 80 ° C. By performing the reaction at 150 ° C. or lower, side reactions can be suppressed, and by performing the reaction at −20 ° C. or higher, the reaction rate can be kept high.

After the reaction in the second step of the production method 1, as the third step, the remaining organic amine compound and / or the reaction between the ester group of the reaction product of polyisocyanate and malonic acid diester produced in the first step and the organic amine compound In order to reduce the amount of the alcohol compound dissociated by (that is, the reaction in the second step), removal purification and the like may be performed.
In order to improve the moisture stability of the resulting coating composition, the organic amine compound (c) remaining after the reaction in the second step is subjected to, for example, removal purification by heating at 20 to 80 ° C. under reduced pressure. It is preferable to reduce the remaining amount. The residual amount of the organic amine compound (c) is preferably 100 mol% or less, more preferably 50 mol% or less, still more preferably 30 mol% or less, and most preferably 10 mol based on the blocked isocyanate group of the blocked polyisocyanate. % Or less. The number of moles of the blocked isocyanate group in this case indicates the number of moles based on the isocyanate group derived from the polyisocyanate which is the precursor.
In addition, in order to improve the moisture stability of the resulting coating composition for the alcohol compound dissociated by the reaction of the ester group of the polyisocyanate and malonic acid diester produced in the first step and the organic amine compound. As with the remaining organic amine compound, it is preferable to reduce the remaining amount. The residual amount of the alcohol compound is preferably 80 mol% or less, more preferably 50 mol% or less, still more preferably 30 mol% or less, and most preferably 10 mol% or less based on the blocked isocyanate group of the blocked polyisocyanate. is there.

  Moreover, the block polyisocyanate composition of this invention may be manufactured collectively by one of said manufacturing methods, and the block polyisocyanate composition manufactured separately may be mixed.

  The block polyisocyanate composition of the present invention is used alone or mixed with a block polyisocyanate derived from two or more kinds of block agents selected from existing active methylene-based, oxime-based, amine-based and pyrazole-based blocking agents. You can also

  However, for example, when a large amount of oxime block polyisocyanate, amine block polyisocyanate, and pyrazole block polyisocyanate is mixed in the coating composition, undesirable effects such as low temperature curability may occur. sell. Therefore, the mixing amount of the block polyisocyanate other than the block polyisocyanate according to the formula (I) is preferably 20% by mass or less, more preferably 10% by weight or less, further preferably 5%, based on the total amount of the block polyisocyanates. It is below mass%.

  Examples of the existing active methylene blocking agent include dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, and acetylacetone. Among these, dimethyl malonate and diethyl malonate are preferable because they are excellent in low-temperature curability. Examples of the oxime blocking agent include formaldehyde oxime, acetoald oxime, acetone oxime, methyl ethyl ketoxime, and cyclohexanone oxime.

  Examples of the amine blocking agent include diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, and isopropylethylamine. Examples of the pyrazole-based blocking agent include pyrazole, 3-methylpyrazole, and 3,5-dimethylpyrazole.

  The number average molecular weight of the block polyisocyanate composition of the present invention is preferably 500 to 5,000. The lower limit is more preferably 700, more preferably 800, and most preferably 1,000. Further, the upper limit is more preferably 4,000, more preferably 3,000, and most preferably 2,000. If the number average molecular weight is 500 or more, the number of functional groups of the blocked isocyanate group per molecule can be ensured to be 2.0 or more, and if the number average molecular weight is 5,000 or less, the viscosity can be increased. Can be suppressed.

  The viscosity of the block polyisocyanate composition of the present invention is 100 to 1,000 mPa · s / 25 ° C. in a resin solid content of 60% by mass diluted with a solvent or the like. If the viscosity is 100 mPa · s or more, it is possible to ensure 2.0 or more functional groups of blocked isocyanate groups per molecule, and if it is 1,000 mPa · s or less, blending into a paint becomes easy. .

  In order to improve the moisture stability of the resulting coating composition, a basic compound (e) having an acid dissociation constant (PKa) of 7.0 to 8.5 with respect to the blocked isocyanate group of the blocked polyisocyanate composition is added. It is preferable to mix 10 mol% or more. The acid dissociation constant (PKa) here is a value measured at 20 ° C. by potentiometric titration. Block polyisocyanate composition in which 10 mol% or more of basic compound (e) having acid dissociation constant (PKa) of 7.0 to 8.5 is mixed with block isocyanate group of a specific active methylene block polyisocyanate composition However, the result of greatly improving the moisture stability as a coating composition while maintaining low-temperature curability was a surprising result.

  Specific examples of the basic compound (e) of PKa 7.0 to 8.5 include morpholine (PKa: 8.4), N-allyl morpholine (PKa: 7.1), and N-methylmorpholine (PKa: 7. 4), morpholine derivatives such as N-ethylmorpholine (PKa: 7.7), triallylamine (PKa: 8.3), triethanolamine (PKa: 7.8), 2-methylimidazole (PKa: 7.8) ), Phthalamide (PKa: 8.3), and the like. Among these, N-allylmorpholine, N-methylmorpholine, N-ethylmorpholine, triethanolamine, and 2-methylimidazole are more preferable, and N-methylmorpholine and N-ethylmorpholine are more preferable.

  The upper limit value of PKa of the basic compound (e) used in the block polyisocyanate composition of the present invention is more preferably 8.3, and more preferably 8.0.

  The mixing amount of the basic compound (e) is preferably 10 mol% or more based on the blocked isocyanate group of the blocked polyisocyanate composition. The lower limit of the mixing amount of the basic compound is more preferably 20 mol%, and further preferably 30 mol%. The upper limit is preferably 500 mol%, more preferably 400 mol%, and even more preferably 300 mol%. The number of moles of the blocked isocyanate group in this case indicates the number of moles based on the isocyanate group derived from the polyisocyanate which is the precursor.

  Moreover, you may mix a part of basic compound (e2) in which PKa exceeds 8.5. The mixing amount is preferably 100 mol% or less, more preferably 50 mol% or less, still more preferably 30 mol% or less, and most preferably 10 mol% or less, based on the blocked isocyanate group of the block polyisocyanate composition.

  The basic compound (e) of PKa 7.0 to 8.5 present in the block polyisocyanate composition of the present invention is preferably added after the first step and the second step are completed, and the first step, It is more preferable to add after the 2nd process and the 3rd process are completed.

  In the present invention, by using a composition containing a block polyisocyanate having the structure of formula (I) as a coating composition, moisture stability and curability after storage are significantly improved while maintaining low temperature curability. Is possible. In the above Patent Document 3, (α) diisopropylamine, (β) active methylene compound, and (γ) a co-block polyisocyanate composition having an oxime as a blocking agent (based on the molar equivalent of the isocyanate group of the polyisocyanate composition). , Α + β + γ = 100 mol%). However, the block polyisocyanate contained in the composition of the present invention is greatly different in that it has the structure of A in the formula (I).

  The block polyisocyanate composition of this invention forms a coating composition by mix | blending with at least 1 sort (s) of a polyol, a polyamine, and an alkanolamine. Furthermore, in order to improve the storage stability when blended with a polyol, the block polyisocyanate composition in the present invention may contain a monohydric alcohol compound. Examples of the monohydric alcohol compound include aliphatic, alicyclic, and aromatic, with aliphatic being preferred. The aliphatic monohydric alcohol compound preferably has 1 to 20 carbon atoms. For example, methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, t-butanol, 2-ethyl-1-propanol N-amyl alcohol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2, Examples include saturated alcohols such as 2-dimethyl-1-propanol, ether alcohols such as 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, and 3,6-dioxa-1-heptanol. The addition amount is preferably 0.2 to 10 times the molar amount of the blocked isocyanate group contained in the composition.

  The block polyisocyanate composition thus prepared becomes a main component of the coating composition together with at least one of polyol, polyamine and alkanolamine. Among these, it is preferable that a polyol is included. Examples of this polyol include polyester polyol, acrylic polyol, polyether polyol, polyolefin polyol, fluorine polyol, polycarbonate polyol, polyurethane polyol and the like.

  As the polyester polyol, for example, a dibasic acid selected from the group of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, or a mixture thereof, Polyester polyol obtained by a condensation reaction with a single or mixture of polyhydric alcohols selected from the group of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, glycerin, and the like, and for example, polyhydric alcohols were used. and polycaprolactones obtained by ring-opening polymerization of ε-caprolactone.

  Acrylic polyol is obtained by copolymerizing an ethylenically unsaturated bond-containing monomer having a hydroxyl group alone or a mixture thereof and another ethylenically unsaturated bond-containing monomer copolymerizable therewith. Is obtained.

  Examples of the ethylenically unsaturated bond-containing monomer having a hydroxyl group include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. It is done. Preferred are hydroxyethyl acrylate and hydroxyethyl methacrylate.

  Other ethylenically unsaturated bond-containing monomers copolymerizable with the above monomers include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, Acrylic acid esters such as acrylic acid-n-hexyl, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, benzyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate Methacrylic acid-n-butyl, isobutyl methacrylate, methacrylic acid-n-hexyl, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, phenyl methacrylate, etc. Acid esters, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, acrylamide, methacrylamide, N, N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, maleic acid amide, maleimide, etc. Unsaturated amides and vinyl monomers such as glycidyl methacrylate, styrene, vinyl toluene, vinyl acetate, acrylonitrile, dibutyl fumarate, vinyltrimethoxysilane, vinylmethyldimethoxysilane, γ- (meth) acryloxypropyltrimethoxy Examples thereof include vinyl monomers having hydrolyzable silyl groups such as silane.

  Polyether polyols include, for example, ethylene oxide, propylene oxide, a single or mixture of polyvalent hydroxy compounds, using, for example, hydroxides such as lithium, sodium and potassium, strong basic catalysts such as alcoholates and alkylamines. Polyether polyols obtained by adding an alkylene oxide such as butylene oxide, cyclohexene oxide or styrene oxide alone or in a mixture, polyether polyols obtained by reacting an alkylene oxide with a polyfunctional compound such as ethylenediamine, and So-called polymer polyols obtained by polymerizing acrylamide or the like using these polyethers as a medium are included.

As the polyvalent hydroxy compound,
(1) Diglycerin, ditrimethylolpropane, pentaerythritol, dipentaerythritol, etc.
(2) Sugar alcohol compounds such as erythritol, D-threitol, L-arabinitol, ribitol, xylitol, sorbitol, mannitol, galactitol, rhamnitol,
(3) monosaccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, ribodesose,
(4) disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, melibiose,
(5) trisaccharides such as raffinose, gentianose, and meletitose,
(6) Tetrasaccharides such as stachyose.

  Examples of the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene. The number of hydroxyl groups (hereinafter, the average number of hydroxyl groups) possessed by one statistical molecule of polyol is preferably 2 or more. When the average number of hydroxyl groups of the polyol is 2 or more, a decrease in the crosslinking density of the obtained coating film can be suppressed.

  The fluorine polyol is a polyol containing fluorine in the molecule. For example, fluoroolefin, cyclovinyl ether, hydroxyalkyl vinyl ether, vinyl monocarboxylate disclosed in JP-A-57-34107 and JP-A-61-275111. There are copolymers such as esters.

Polycarbonate polyols are polycondensation of low molecular carbonate compounds such as dialkyl carbonates such as dimethyl carbonate, alkylene carbonates such as ethylene carbonate, diaryl carbonates such as diphenyl carbonate, and low molecular polyols used in the aforementioned polyester polyols. Can be obtained.
The polyurethane polyol can be obtained by a conventional method, for example, by reacting a polyol with a polyisocyanate. Examples of the polyol not containing a carboxyl group include ethylene glycol and propylene glycol as low molecular weights, and examples of the high molecular weight include acrylic polyol, polyester polyol, and polyether polyol.

  The hydroxyl value per resin of the polyol is preferably 10 to 300 mgKOH / resin g. When the hydroxyl value per resin is 10 mgKOH / g or more of resin, it is possible to prevent the crosslink density from being reduced and to sufficiently achieve the object physical properties of the present invention. On the other hand, when the hydroxyl value per resin is 300 mgKOH / resin g or less, an excessive increase in the cross-linking density can be suppressed, and the mechanical properties of the coating film can be maintained at a high level.

  The acid value per resin of the polyol is preferably 5 to 150 mgKOH / resin g, more preferably 8 to 120 mgKOH / resin g, and still more preferably 10 to 100 mgKOH / resin g. When the acid value is 5 mgKOH / resin g or more, water dispersibility is kept high, and when it is 150 mgKOH / resin g or less, the water resistance of the coating film can be prevented from being lowered.

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

As the polyamine, those having two or more primary amino groups or secondary amino groups in one molecule are used, and among them, those having three or more in one molecule are preferable.
Specific examples of polyamines include ethylenediamine, propylenediamine, butylenediamine, triethylenediamine, hexamethylenediamine, 4,4′-diaminodicyclohexylmethane, piperazine, diamines such as 2-methylpiperazine, isophoronediamine, bishexamethylenetriamine, Chain polyamines having three or more amino groups such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentamethylenehexamine, tetrapropylenepentamine, 1,4,7,10,13,16-hexaazacyclooctadecane Cyclic polyamines such as 1,4,7,10-tetraazacyclodecane, 1,4,8,12-tetraazacyclopentadecane and 1,4,8,11-tetraazacyclotetradecane. The

  Moreover, alkanolamine here means the compound which has an amino group and a hydroxyl group in 1 molecule. For example, monoethanolamine, diethanolamine, aminoethylethanolamine, N- (2-hydroxypropyl) ethylenediamine, mono-, di- (n- or iso-) propanolamine, ethylene glycol-bis-propylamine, neopentanolamine And methylethanolamine.

The basic compound (e) of PKa 7.0 to 8.5 may be added at the time of blending the paint. In that case, you may use together with the basic compound (e2) in which pKa exceeds 8.5. The composition ratio of the weak basic compound (e) to the sum of the weak basic compound (e) and the basic compound (e2) (total basic composition) is preferably 20 mol% or more. The lower limit value of the composition ratio of the weakly basic compound (e) is preferably 30 mol%, more preferably 40 mol%, still more preferably 50 mol%. Examples of the acidic group to be neutralized include a carbonyl group and a sulfonyl group, among which a carbonyl group is preferable. Moreover, about the carboxyl group in the case of the polyol which has a carboxyl group, the addition amount of all the basic compositions can be determined on the basis of the acid component of the preparation at the time of polyol manufacture.
The addition amount of the total basic composition is preferably 30 mol% or more with respect to 100 mol% of the total acidic content of the basic group present in each component in the paint. As a lower limit, More preferably, it is 50 mol%, More preferably, it is 70 mol%, Most preferably, it is 100 mol% or more. Moreover, as an upper limit, Preferably it is 500 mol%, More preferably, it is 400 mol%, More preferably, it is 300 mol%.

  An existing melamine resin, epoxy resin, and polyurethane resin can be blended with the coating composition containing the block polyisocyanate composition of the present invention. Moreover, when the polyol mentioned above has a carboxyl group, an oxazoline group containing compound and a carbodiimide group containing compound can be mix | blended. Moreover, when the polyol mentioned above has a carbonyl group, a hydrazide group containing compound and a semicarbazide group containing compound can be mix | blended. These compounds can be blended not only alone but also two or more compounds.

  Examples of the melamine resin include a partial or completely methylolated melamine resin obtained by a reaction between melamine and an aldehyde. Examples of the aldehyde include formaldehyde and paraformaldehyde. Moreover, what methylated the methylol group of this methylol-ized melamine resin partially or completely etherified with alcohol can also be used. Examples of alcohols used for etherification include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-ethylbutanol, 2-ethylhexanol and the like.

  Specific examples of the melamine resin include Cymel 303, Cymel 323, Cymel 325, Cymel 327, Cymel 350, Cymel 370, Cymel 380, Cymel 385, Cymel 212, Cymel 251, Cymel 254, My Coat manufactured by Nippon Cytec Industries, Ltd. 776 (all are trade names).

  When a melamine curing agent is used in combination, an acidic compound is effective as a catalyst for curing. Specific examples of the acidic compound include carboxylic acid, sulfonic acid, acidic phosphate ester, and phosphite ester.

  Typical examples of the carboxylic acid include acetic acid, lactic acid, succinic acid, oxalic acid, maleic acid, and decanedicarboxylic acid. Typical examples of the sulfonic acid include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and dinonylnaphthalenedisulfonic acid. Examples of acidic phosphate esters include dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, dilauryl phosphate, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, and monooctyl phosphate. Typical examples of phosphites include diethyl phosphite, dibutyl phosphite, dioctyl phosphite, dilauryl phosphite, monoethyl phosphite, monobutyl phosphite, monooctyl phosphite and monolauryl phosphite. .

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

  The polyurethane resin is not limited as long as it is generally used in paints, but a polyurethane resin that is chain-extended by reacting an isocyanate group with a polyol is preferable. The polyurethane resin includes those having a carboxyl group obtained by using a carboxyl group-containing polyol as part of the polyol, and those having a hydroxyl group at the terminal. The polyurethane resin having a carboxyl group is preferably neutralized with a basic substance. Examples of commercially available products include Superflex series 110, 150, 460S (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Neoletz R9649, R966 (trade name, manufactured by Avicia).

  Examples of the oxazoline group-containing compound include a polymer compound having at least two oxazoline groups in the side chain, and a monomer compound having at least two oxazoline groups in the molecule.

  The carbodiimide group-containing compound can be obtained, for example, by subjecting the isocyanate groups of the polyisocyanate compound to a carbon dioxide removal reaction. Examples of commercially available carbodiimide group-containing compounds include Carbodilite V-02, Carbodilite V-02-L2, Carbodilite V-04, Carbodilite E-01, Carbodilite E-02 (all manufactured by Nisshinbo Co., Ltd., trade names), and the like. Can be mentioned.

The hydrazide group-containing compound includes a compound having at least 2, preferably 2 to 10, hydrazide groups represented by —CO—NH—NH ₂ in one molecule. Examples of the hydrazide group-containing compound include saturated dicarboxylic acid dihydrazides having 2 to 18 carbon atoms such as oxalic acid dihydrazide, malonic acid dihydrazide, glutaric acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide; maleic acid dihydrazide Monoolefinic unsaturated dicarboxylic acid dihydrazides such as fumaric acid dihydrazide and itaconic acid dihydrazide; polyhydrazides obtained by reacting a low polymer having a carboxylic acid lower alkyl ester group with hydrazine or hydrazine hydrate, etc. .

The semicarbazide group-containing compound includes a compound having at least two, preferably 2 to 10, semicarbazide groups represented by —NH—CO—NH—NH ₂ in one molecule. As a semicarbazide group-containing compound, for example, bissemicarbazide; a diisocyanate such as hexamethylene diisocyanate or isophorone diisocyanate or a polyisocyanate compound derived therefrom is reacted with N, N-substituted hydrazine such as N, N-dimethylhydrazine or the hydrazine exemplified above. And polyfunctional semicarbazide obtained by the reaction.

  If necessary, the coating composition of the present invention comprises an antioxidant such as hindered phenol, an ultraviolet absorber such as benzotriazole and benzophenone, a pigment such as titanium oxide, carbon black, indigo, quinacridone, and pearl mica. Powder pigments such as aluminum, rheology control agents such as hydroxyethyl cellulose, urea compounds and microgels, and curing accelerators such as tin compounds, zinc compounds and amine compounds may also be included.

  The coating composition prepared in this manner is applied to a material such as a steel plate, surface-treated steel plate and other metals and plastics, and inorganic materials by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, etc. It is suitably used as an intermediate coating or top coating. In addition, this coating composition is intended to impart cosmetics, weather resistance, acid resistance, rust resistance, chipping resistance, adhesion, etc. to pre-coated metal, automobile coating, plastic coating, etc. that further include a rust-proof steel plate. Preferably used. The coating composition is also useful as a raw material for urethane such as adhesives, pressure-sensitive adhesives, elastomers, foams, and surface treatment agents.

The coating composition of the present invention forms a coating film through a baking process after coating by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating or the like. This coating composition preferably has a crosslinked coating film formed through a baking step. The crosslinked coating film after curing of the coating composition is characterized by having not only a polyisocyanate-derived urethane bond before the blocking reaction but also polar groups such as an amide bond and an ester bond derived from a blocked isocyanate group. Therefore, the crosslinked coating formed from the coating composition of the present invention has chemical resistance, heat resistance, water resistance, etc., which are the characteristics of a general urethane crosslinked coating, It is possible to perform hydrogen bonding between the layers and to have excellent adhesion between the layers. Even in the coating film in which the crosslinked structure is not completely formed after the baking step, it has the above-mentioned polar group, so that it is excellent in adhesion as well as the crosslinked coating film at the time of lamination coating or recoating.
In addition, when laminating several layers of coating liquid wet-on-wet like painting on a new car line of an automobile, since an organic amine compound is present in the coating composition of the present invention or in the crosslinked coating film after curing, There is also the possibility of acting as a catalyst for the crosslinking reaction of the lower layer or the upper layer.

  Below, based on an Example, this invention is demonstrated still in detail. First, measurement and evaluation methods for various physical properties will be described.

<Measurement method>
(Measurement of number average molecular weight)
The number average molecular weight of the polyisocyanate is a polystyrene-based number average molecular weight measured by gel permeation chromatography (hereinafter referred to as GPC) using the following apparatus.
Equipment: Tosoh Corporation HLC-8120GPC (trade name)
Column: Tosoh Corporation TSKgel SuperH1000 (trade name) 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 is a polystyrene-based number average molecular weight measured by GPC measurement described below.
Equipment: Tosoh Corporation HLC-8120GPC (trade name)
Column: Tosoh Corporation TSKgel SuperHM-H (trade name) x 2 Carrier: N, N-dimethylformamide Detection method: differential refractometer

(Measurement of viscosity)
Using an E type viscometer (VISCONIC ED type (trade name) manufactured by Tokimec Co., Ltd.), the measurement was performed at 25 ° C.

(Calculation of effective NCO group mass%)
The effective NCO group mass% here is used to quantify the amount of blocked isocyanate groups that can participate in the crosslinking reaction present in the blocked polyisocyanate composition after the blocking reaction, and is expressed as mass% of isocyanate groups. Expressed by the following formula.
{(Solid content (mass%) of block polyisocyanate composition) × (mass of polyisocyanate used in reaction × isocyanate group content% of precursor polyisocyanate)} / (block polyisocyanate composition after blocking reaction) Resin mass)
When diluted with a solvent or the like, the value in the diluted state is described.

(X, y ratio of block polyisocyanate)
Remaining mole% of isocyanate group (p) after reaction in the first step in the production method 1, reaction mole% (q) of the organic amine compound after the second step, mole% added to the isocyanate group of the organic amine compound in the second step When (r), it was calculated from the following formula.
In the case of p ≠ 0, the organic amine compound reacts preferentially with the remaining isocyanate group, and therefore the amount of the organic amine compound needs to be considered from the reaction amount of the organic amine compound. Therefore, it calculated as x = {(q * r) -p} and x / y = {(q * r) -p} / (100-x). The remaining mole% of isocyanate groups after the first step is quantified by infrared spectrum measurement of the reaction solution, and the reaction rate of the organic amine compound is quantified by gas chromatograph measurement of the amount of the organic amine compound decreased after the second step. Calculated by.
Device: Shimadzu GC-14A (trade name)
Column: DB-1 (trade name) manufactured by Shimadzu GC
In addition, the block polyisocyanate which has a substituent shown by Formula (VI) can be produced | generated when 2 mol equivalent of the organic amine of a 2nd process reacts with 1 mol equivalent of malonic acid diester part. However, when a secondary amine is used as the organic amine in the second step from the experimental results with the model compound (using n-hexyl isocyanate as the isocyanate component), it is probably 1% by mass of the total of the blocked polyisocyanate due to steric hindrance. It turns out that it only produces: Therefore, in the calculation of the x / y ratio, the formation of a blocked polyisocyanate having a substituent of formula (VI) was ignored.
Further, the malonic acid diester remaining in the first step can react with the organic amine compound added in the second step. However, since the total amount of malonic acid monoester monoamide and malonic acid diamide is 1% by mass or less by gas chromatographic measurement in the above model experiment example, x / y of the secondary amine used as the organic amine is In the calculation, the decrease in organic amine due to this reaction was ignored.

(Structure identification of block polyisocyanate: NMR measurement)
The structure of the block polyisocyanate was identified from ¹ H-NMR measurement using the following apparatus. Chemical shift standard: Tetramethylsilane was 0 ppm.
The keto methine proton of the reaction product of the isocyanate group and malonic acid diester, which was the product of the first step, was observed near 4.3 ppm, and the enol proton was observed around 16.5 ppm. Further, the methine proton of the keto form of the formula (II) A which is the product after the second step was observed around 4.5 ppm, and the enol form proton was observed around 19.2 ppm. From the integrated values of these peaks, the reaction ratio in the second step and the abundance ratio of keto and enol bodies were confirmed.
Equipment: ECS-400 (trade name) manufactured by JEOL
Solvent: Deuterated chloroform Accumulated times: 128 Sample concentration: 5% by mass
Chemical shift standard: Tetramethylsilane was 0 ppm.

(Initial gel fraction)
The prepared coating solution was coated with an applicator so as to have a film thickness of 40 μm, and baked at 90 ° C. for 30 minutes to obtain a cured coating film. The cured coating film was baked, allowed to stand at 20 ° C. for 1 hour, immersed in acetone at 20 ° C. for 24 hours, and then the value of the undissolved part mass relative to the mass before immersion was calculated. ◎ when the gel fraction is 85% or more, ○ when it is 80% or more and less than 85%, ○ △ when it is 70% or more and less than 80%, △ when it is 60% or more but less than 70%, 50% or more but less than 60% The case of x was taken as x, and the case of less than 50% was taken as x.

(Gel fraction retention after storage)
The prepared coating solution was stored at 40 ° C. for 10 days, then, after drying, an applicator was applied to a film thickness of 40 μm and baked at 90 ° C. for 30 minutes to obtain a cured coating film. The cured coating film was baked, allowed to stand at 20 ° C. for 1 hour, immersed in acetone at 20 ° C. for 24 hours, and then the value of the undissolved part mass relative to the mass before immersion (gel fraction after storage) was calculated. The gel fraction after storage is ◎ when the gel fraction after storage / initial gel fraction = 0.90 or more, ○ when 0.85 or more and less than 0.90, and 0.80 or more and less than 0.85 Is Δ, 0.75 or more and less than 0.80 is indicated as x, and less than 0.75 is indicated as xx.

(Moisture stability test)
30 mmol of the block polyisocyanate composition as an effective NCO group was taken, and 5.4 g of water (corresponding to 300 mmol) was added thereto, and then diethylene glycol dimethyl ether was added so that the total mass of the solution became 200 g, followed by stirring. Thus, a test solution was obtained. Transfer the solution to a 300 cc Erlenmeyer flask, and fix the tip of the measuring pipette fixed with a silicone rubber stopper with the tip immersed in the liquid surface. The amount of gas generated was measured based on the height of the surface. When stored at 40 ° C. for 10 days, the amount of gas (carbon dioxide) generated during that period is less than 4 cc, ◎ if 4 cc or more but less than 8 cc, ◎ if 8 cc or more and less than 16 cc, ○, 16 cc or more and 24 cc The case of less than △, the case of 24 cc or more and less than 32 cc was indicated as ×, and the case of 32 cc or more was designated as XX.

(Production Example 1) (Production of HDI isocyanurate type polyisocyanate)
The inside of a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen blowing tube was purged with nitrogen, charged with 1000 g of HDI, and stirred at 60 ° C., 0.1 g of trimethylbenzylammonium hydroxide as a catalyst Was added. After 4 hours, when the conversion rate of the reaction solution reached 38%, 0.2 g of phosphoric acid was added to stop the reaction. Thereafter, the reaction solution was filtered, and unreacted HDI monomer was removed by thin film distillation.
The obtained polyisocyanate had a viscosity at 25 ° C. of 2,700 mPa · s, an isocyanate group content of 22.2% by mass, a number average molecular weight of 650, and an average number of isocyanate groups of 3.4. Thereafter, the presence of an isocyanurate bond was confirmed by NMR measurement.

(Production Example 2) (Production of HDI urethane bond, allophanate bond-containing isocyanurate type polyisocyanate)
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen blowing tube is placed in a nitrogen atmosphere, charged with HDI: 1000 parts by mass, trimethylolpropane (molecular weight 134) 22 parts by mass as a trihydric alcohol, While stirring, the temperature in the reactor was maintained at 90 ° C. for 1 hour for urethanization. Thereafter, the temperature of the reaction solution was kept at 60 ° C., an isocyanuration catalyst trimethylbenzylammonium hydroxide was added, and phosphoric acid was added when the conversion rate reached 48% to stop the reaction. Then, after filtering a reaction liquid, unreacted HDI was removed with the thin film distillation apparatus.
The obtained polyisocyanate had a viscosity at 25 ° C. of 25,000 mPa · s, an isocyanate group content of 19.9% by mass, a number average molecular weight of 1080, and an average number of isocyanate groups of 5.1. Thereafter, the presence of urethane bond, allophanate bond and isocyanurate bond was confirmed by NMR measurement.

(Production Example 3) (Production of HDI, IPDI-based urethane bond, allophanate bond-containing isocyanurate type polyisocyanate)
A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube is placed in a nitrogen atmosphere, and HDI: 700 parts by mass, IPDI: 300 parts by mass, polycaprolactone-based polyester polyol “Placcel” 303 "(Daicel Chemical's product name: molecular weight 300) 30 parts by mass, and the reactor temperature was maintained at 90 ° C for 1 hour with stirring to perform urethanization. Thereafter, the reaction liquid temperature was kept at 60 ° C., an isocyanuration catalyst trimethylbenzylammonium hydroxide was added, and phosphoric acid was added when the conversion rate was 42% to stop the reaction. Then, after filtering a reaction liquid, unreacted HDI and IPDI were removed with the thin film distillation apparatus.
The obtained polyisocyanate had a viscosity at 25 ° C. of 60,000 mPa · s, an isocyanate group content of 18.9% by mass, a number average molecular weight of 900, and an isocyanate group average number of 4.1. Thereafter, the presence of urethane bond, allophanate bond and isocyanurate bond was confirmed by NMR measurement.

(Example 1) (Production of block polyisocyanate composition)
A 4-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was placed in a nitrogen atmosphere, and 100 parts by mass of the polyisocyanate obtained in Production Example 1 (isocyanate group of polyisocyanate in this case) The number of moles was set to 100), 92.4 parts by mass of n-butyl acetate, and 88.9 parts by mass of diethyl malonate (corresponding to 105 mol% of the isocyanate groups in the polyisocyanate) were charged and maintained at 60 ° C. Thereafter, 0.77 parts by mass of 28% sodium methylate was added and held for 4 hours. As a result of measuring the infrared spectrum, disappearance of the isocyanate group was confirmed, and 0.76 parts by mass of 2-ethylhexyl acid phosphate was added.
Subsequently, 53.5 parts by mass of diisopropylamine (corresponding to 100 mol% of the isocyanate group in the polyisocyanate) was added, and the reaction solution temperature was maintained at 70 ° C. for 5 hours. This reaction solution was analyzed by gas chromatography, and it was confirmed that the reaction rate of disisopropylamine was 70%. Thereafter, 19.6 parts of n-butanol was added to obtain a block polyisocyanate composition having a solid concentration of 60% by mass. Table 1 shows the physical properties of the obtained block polyisocyanate composition and the structure of formula (I) of the block polyisocyanate.
Separately, the above-mentioned block polyisocyanate composition was transferred to an eggplant flask and distilled off under reduced pressure at 60 ° C. and 10 hPa for 60 minutes using an evaporator to remove most of the solvent, followed by NMR measurement. . As a result, x / y in formula (I) was 2.4. Moreover, the keto body / enol body composition ratio of the A component was 99/1.

(Example 8) (Production of block polyisocyanate composition)
A 4-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was placed in a nitrogen atmosphere, and 100 parts by mass of the polyisocyanate obtained in Production Example 2 (the isocyanate group of the polyisocyanate in this case) The number of moles is 100), 92.7 parts by mass of propylene glycol monomethyl ether acetate, and 60.7 parts by mass of diethyl malonate (corresponding to 80 mol% of the isocyanate groups in the polyisocyanate composition) were charged and maintained at 60 ° C. . Thereafter, 0.68 parts by mass of 28% sodium methylate was added and held for 4 hours. As a result of measuring the infrared spectrum, it was confirmed that the residual ratio of the isocyanate group was 22%, and 0.66 parts by mass of 2-ethylhexyl acid phosphate was added.
Subsequently, 47.9 parts by mass of diisopropylamine (corresponding to 100 mol% of the isocyanate group in the polyisocyanate) was added, and the reaction solution temperature was maintained at 70 ° C. for 5 hours. This reaction solution was analyzed by gas chromatography, and it was confirmed that the reaction rate of disisopropylamine was 80%. Thereafter, this reaction solution was transferred to an eggplant flask and distilled off under reduced pressure for 30 minutes at 60 ° C. and a reduced pressure of 10 hPa using an evaporator. When the mass of vacuum distillation implementation was measured, solid content of the reaction liquid was 73 mass%. Thereafter, 53.9 parts by mass of propylene glycol monomethyl ether acetate was added again to obtain a block polyisocyanate composition having a solid concentration of 60% by mass. When the residual amounts of ethanol and diisopropylamine were measured by gas chromatography, they were 0.3% by mass and 0.4% by mass, respectively. Table 1 shows the physical properties of the obtained block polyisocyanate composition and the structure of formula (I) of the block polyisocyanate.

(Examples 2-7, 9-15, Comparative Example 1) (Production of Block Polyisocyanate Composition)
The same procedure as in Example 1 was performed except that the components and ratios shown in Table 1 were used. Table 1 shows the physical properties of the obtained block polyisocyanate composition and the structure of formula (I) of the block polyisocyanate.

(Comparative Example 2) (Production of Block Polyisocyanate Composition)
A 4-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was placed in a nitrogen atmosphere, and 100 parts by mass of the polyisocyanate obtained in Production Example 1 (isocyanate group of polyisocyanate in this case) And 97.8 parts by mass of n-butyl acetate were charged and maintained at 40 ° C. Thereafter, 52.3 parts by mass of 3,5-dimethylpyrazole (corresponding to 103 mol% of the isocyanate group in the polyisocyanate composition) was added in five portions. After completion of the addition, the mixture was stirred for 1 hour, and then the infrared spectrum was measured. As a result, disappearance of the isocyanate group was confirmed, and a block polyisocyanate composition having a solid content concentration of 60% by mass was obtained. Table 1 shows the physical properties of the obtained block polyisocyanate composition and the structure of formula (I) of the block polyisocyanate.

(Comparative Example 3) (Production of Block Polyisocyanate Composition)
A 4-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was placed in a nitrogen atmosphere, and 100 parts by mass of the polyisocyanate composition obtained in Production Example 2 (the polyisocyanate in this case) And 92.9 parts by mass of n-butyl acetate were charged and maintained at 40 ° C. Thereafter, 42.5 parts by mass of methyl ethyl ketoxime (corresponding to 103 mol% of the isocyanate group in polyisocyanate) was dropped from the dropping funnel. After completion of dropping, the mixture was stirred for 1 hour, and then the infrared spectrum was measured. As a result, disappearance of the isocyanate group was confirmed, and a block polyisocyanate composition having a solid content concentration of 60% by mass was obtained. Table 1 shows the physical properties of the obtained block polyisocyanate composition and the structure of formula (I) of the block polyisocyanate.

(Comparative Example 4) (Production of Block Polyisocyanate Composition)
A 4-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was placed in a nitrogen atmosphere, and 100 parts by mass of the polyisocyanate obtained in Production Example 1 (isocyanate group of polyisocyanate in this case) The number of moles was set to 100), 92.4 parts by mass of n-butyl acetate, and 42.3 parts by mass of diethyl malonate (corresponding to 50 mol% of the isocyanate groups in the polyisocyanate) were charged and maintained at 60 ° C. Thereafter, 0.58 parts by mass of 28% sodium methylate was added and held for 4 hours. As a result of measuring the infrared spectrum, the disappearance of the isocyanate group corresponding to the added mole of diethyl malonate was confirmed, and 0.57 parts by mass of 2-ethylhexyl acid phosphate was added.
Subsequently, 26.8 parts by mass of diisopropylamine (corresponding to 50 mol% of the isocyanate groups in the polyisocyanate) was added, and the reaction solution temperature was maintained at 70 ° C. for 5 hours. Thereafter, the disappearance of the isocyanate group was confirmed by infrared spectrum measurement. As a result of analysis by gas chromatography, it was confirmed that ethanol and disisopropylamine were not present. Thereafter, 20.3 parts of n-butanol was added to obtain a block polyisocyanate composition having a solid concentration of 60% by mass. Table 1 shows the physical properties of the obtained block polyisocyanate composition and the structure of formula (I) of the block polyisocyanate.

The comment on the * part in Table 1 is as follows.
* 1 mol% of (number of moles of each compound) / (number of moles of isocyanate group of polyisocyanate)
* 2 2-Ethylhexyl acid phosphate (trade name of Johoku Chemical Industry)
* 3 Value calculated from GC analysis of (number of moles of amine lost) / (number of moles of amine added to reaction) * 4% by mass of effective NCO group as a formulation shown in Table 1 (calculated value)
* 5 Residue excluding active hydrogen of the compound described in <> D6: Diethyl malonate (R1: ethyl group, R2: ethyl group)
* 7 DIPA: diisopropylamine (R3: isopropyl group, R4: isopropyl group)
* 8 PMA: Propylene glycol monomethyl ether acetate * 9 DNBA: Di-n-butylamine (R3: n-butyl group, R4: n-butyl group)
* 10 Mixture of R3 and R4 derived from DNBA, which is a chain amine compound, and 2,6-dimethylpiperidine, which is a cyclic amine compound containing a nitrogen atom. * 11 DIPM: Diisopropyl malonate (R1: isopropyl group, R2: isopropyl group)
* 12 ECHA: N-ethylcyclohexylamine (R3: ethyl group, R4: cyclohexyl group)
* 13 N75BA (75% butyl acetate solution of biuret-type polyisocyanate composition of hexamethylene diisocyanate: trade name of Bayer)
* 14 ME20-100 (urethane of hexamethylene diisocyanate and polyol, allophanate type polyisocyanate composition: trade name of Asahi Kasei Chemicals Corporation)
* 15 DMM: dimethyl malonate (R1: methyl group, R2: methyl group)
* 16 VESTANAT T1890E (70% butyl acetate solution of isocyanurate type polyisocyanate composition of isophorone diisocyanate: trade name of Evonik Degussa)
* 17 Coronate L (75% ethyl acetate solution of urethane type polyisocyanate composition of tolylene diisocyanate and trimethylolpropane: trade name of Nippon Polyurethane Industry Co., Ltd.)
* 18 Mixture of residues excluding active hydrogen of diethyl malonate and residues excluding active hydrogen of diisopropylamine * 19 2,2,6,6 which is a chain amine compound DIPA and a cyclic amine compound containing a nitrogen atom -Mixture of R3 and R4 derived from tetramethylpiperidine * 20 DPhM: diphenyl malonate (R1: phenyl group, R2: phenyl group)
* 21 R3, R4 derived from 2,6-dimethylpiperidine, a cyclic amine compound containing a nitrogen atom

(Example 16) (Initial gel fraction of block polyisocyanate composition, measurement of gel fraction retention after storage, evaluation of moisture stability)
The main component is acrylic polyol (trade name “A801” from DIC Corporation, resin concentration 50 mass%, hydroxyl value per resin 100 mg KOH / g) 100 parts by mass, and block polyisocyanate composition 60. 4 parts by mass (mixed with an equivalent ratio of the blocked isocyanate group to the hydroxyl group of the main agent at 1.0) was adjusted with butyl acetate so that the solid content of the paint was 40% by mass. The prepared coating solution was dried and then coated with an applicator so as to have a film thickness of 40 μm, baked at 90 ° C. for 30 minutes, and the initial gel fraction was measured. The results are shown in Table 2.
Moreover, after storing the coating solution prepared above at 40 ° C. for 10 days, a baked coating film was prepared by the above method, and the gel fraction after storage was measured. Table 2 shows the gel fraction retention after storage. Further, 20.3 g of a block polyisocyanate composition (corresponding to 30 mmol as an effective NCO group) was blended with 5.4 g of water (corresponding to 300 mmol), and finally 174.3 g of diethylene glycol dimethyl ether (a total of 200 g of these three components) Were prepared) and stirred to obtain a block polyisocyanate composition solution. The amount of gas (carbon dioxide) generated during storage of this solution at 40 ° C. for 10 days was measured. The results are shown in Table 2.

(Example 17-30, Comparative Example 5-8) (Initial gel fraction of block polyisocyanate composition, measurement of gel fraction retention after storage, moisture stability evaluation)
The same procedure as in Example 16 was performed except that the components and ratios shown in Table 2 were used. Table 2 shows the results of the initial gel fraction, the gel fraction retention after storage, and the moisture stability of the obtained block polyisocyanate composition.

(Example 31) (Measurement of gel fraction of block polyisocyanate composition)
22.9 parts by mass of the block polyisocyanate composition obtained in Example 2, 16.5 parts by mass of water, sodium dialkylsulfosuccinate (trade name “New Coal 290M” of Nippon Emulsifier Co., Ltd., solid content 70% by mass) 3 Each part by mass was added and mixed with a homomixer. After mixing, a milky white aqueous dispersion was obtained. Then, 100 parts by weight of this aqueous dispersion and acrylic emulsion (resin concentration 42 mass%, hydroxyl value per resin 40 mg KOH / g, Tg 20 ° C., number average molecular weight 170,000) were mixed (block isocyanate group and hydroxyl group of main component). The equivalent ratio is 1.0 and the solid content of the paint is adjusted to 40% by mass). After mixing, a milky white aqueous dispersion was obtained. The prepared coating solution was dried and then coated with an applicator so as to have a film thickness of 40 μm, baked at 90 ° C. for 30 minutes, and the gel fraction was measured. The results are shown in Table 2.

The annotations of the * part in Table 2 are as follows.
* 22 Acrylic polyol (trade name “A801” from DIC Corporation, resin concentration 50 mass%, hydroxyl value per resin 100 mg KOH / g)
* 23 Acrylic emulsion (resin concentration 42 mass%, hydroxyl value per resin 40 mg KOH / g, Tg 20 ° C., number average molecular weight 170,000)

  From the results of the above Examples and Comparative Examples, the block polyisocyanate composition of the present invention was found to be crosslinkable at a baking temperature of 100 ° C. or less and excellent in moisture stability.

  The block polyisocyanate composition of the present invention can be suitably used as a coating composition having excellent low-temperature curability, moisture stability, and curability after storage.

Claims (11)

A block polyisocyanate composition comprising at least one block polyisocyanate represented by the following formula (I):

(In the formula, R is a residue excluding an isocyanate group of a polyisocyanate formed from one or more selected from aliphatic polyisocyanate, alicyclic polyisocyanate, and aromatic polyisocyanate, and A is , One or more keto isomers represented by the following formula (II) or enol isomers thereof, and B is one or more structural units represented by the formula (III), (The sum of x and y is 2.0 to 20, and x is not 0.)

(In the formula, R ₁ represents an alkyl group having 1 to 8 carbon atoms, a phenyl group or a benzyl group, and R ₃ and R ₄ may be the same or different, and may be any one having 1 to 30 carbon atoms. Is a hydrocarbon group that may contain at least one selected from an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol group, and R ₃ and R ₄ are optionally combined together to form a 5-membered or 6-membered cyclohexane. 3-membered, 4-membered, 5-membered or 6-membered which may form an alkyl group or may contain an additional nitrogen or oxygen atom as a bridging member together with a nitrogen atom sandwiched between R ₃ and R ₄ A ring can be formed.)

(In the formula, R ₅ is a residue excluding active hydrogen of the active hydrogen-containing compound.)   The block polyisocyanate composition according to claim 1, wherein x and y in formula (I) satisfy x / y ≧ 1.   The block according to claim 1 or 2, wherein R in formula (I) is a residue other than an isocyanate group of a polyisocyanate formed from one or more selected from aliphatic diisocyanates and alicyclic diisocyanates. Polyisocyanate composition. The block polyisocyanate composition according to any one of claims 1 to 3, wherein R _{1 in the} formula (II) is an alkyl group having 1 to 4 carbon atoms. The block polyisocyanate composition according to any one of claims 1 to 4, wherein R ₃ and R _{4 in} the formula (II) are both branched alkyl groups having 3 to 6 carbon atoms. The block polyisocyanate composition according to any one of claims 1 to 4, wherein (R ₃ ) (R ₄ ) N- in formula (II) is a linked structure represented by formula (IV).

(In the formula, R ₆ , R ₇ , R ₈ and R ₉ each independently represent hydrogen or a methyl group, and at least one of them is a methyl group.) The block polyisocyanate composition according to claim 5, wherein R ₃ and R _{4 in} the formula (II) are both isopropyl groups. X and y in formula (I) are x / y ≧ 2, and R ₅ in formula (III) is a residue excluding active hydrogen of a malonic acid diester compound, The block polyisocyanate composition according to any one of 7 above.   The basic compound (e) having an acid dissociation constant (PKa) of 7.0 to 8.5 is contained in an amount of 10 mol% or more based on the blocked isocyanate group of the blocked polyisocyanate composition. The block polyisocyanate composition in any one of Claims 1-8 which shows the number of moles on the basis of the isocyanate group derived from the polyisocyanate which is a precursor.   The coating composition containing the block polyisocyanate composition in any one of Claims 1-9, and a polyol.   A coating film comprising the coating composition according to claim 10.