JP5572567B2 - Method for producing a block polyisocyanate composition - Google Patents

Description

  The present invention is a method for producing a block polyisocyanate composition capable of forming a crosslinked coating film at a temperature of 100 ° C. or less, having excellent storage stability as an aqueous coating composition, and good curability after storage. About.

  In recent years, water-based paints have attracted attention from the viewpoints of the global environment, safety, and hygiene. Among these, various water-based paints have been proposed for automobile paints and architectural paints. Among water-based paints, urethane-based paints that are cross-linked by isocyanate groups have very excellent wear resistance, chipping resistance, chemical resistance, and stain resistance.

  In such a urethane-based paint, when a one-component property such as a line paint is required, a blocked isocyanate obtained by blocking a free isocyanate group of a polyisocyanate with a thermal dissociation blocking agent is usually used. Although this blocked isocyanate does not react with the polyol at room temperature, the blocking agent is dissociated by heating, and the active isocyanate group is regenerated to cause a crosslinking reaction with the polyol. As the blocking agent, those based on methyl ethyl ketoxime, caprolactam, alcohol and phenol are used. However, even in the oxime block isocyanate that can form a crosslinked coating film at the lowest temperature among these, a high baking temperature of 140 ° C. or higher is generally required. Therefore, the energy cost becomes very large. Moreover, there has been a limitation that a blocked isocyanate that requires high-temperature baking cannot be used for processing into a plastic having low heat resistance.

  In order to overcome such drawbacks, a pyrazole-based blocked isocyanate has been proposed as a blocked isocyanate that forms a crosslinked coating film at a relatively low temperature (Patent Document 1). However, pyrazole-based blocked isocyanates also require a baking temperature of about 120 ° C., and further reduction in baking temperature has been desired.

  Furthermore, active methylene-based blocked isocyanate has been proposed as a blocked isocyanate that forms a crosslinked coating film at a low temperature (Patent Documents 2 to 5). In Patent Document 2, malonic acid diester and acetoacetic acid ester are used as a blocking agent, and water dispersibility is improved by using a nonionic hydrophilic group compound. In Patent Document 3, malonic acid diester and / or acetoacetic acid ester is used as a blocking agent, and further, after chain extension with an aliphatic / alicyclic diamine, formaldehyde is added and incorporated to improve storage stability. ing.

  In Patent Document 4, malonic acid diester and / or acetoacetate is used as a blocking agent, and the ester part is transesterified with an alcohol compound containing a group capable of becoming a hydrophilic group, thereby improving water dispersibility. ing. In Patent Document 5, storage stability is improved by using a malonic acid diester and / or an acetoacetic acid ester as a blocking agent, and further emulsifying using a hydrophilic compound having a sulfonic acid group and a polyamine compound.

  However, when using the one-component water-based paint curing agent of Patent Documents 2 to 5, if water is present, the decomposition reaction of the malonic acid diester block can proceed to generate carbon dioxide, or water. In the presence of, the decomposition reaction of the acetoacetate block body in the basic structure proceeds, and there is a problem that the curability after storage may be lowered.

  Patent Document 6 proposes a new active methylene-based blocked isocyanate, which shows that the generation of carbon dioxide gas is suppressed. However, depending on the polyol used, the pH of the coating liquid may decrease.

  Therefore, there has been a demand for a blocked isocyanate composition capable of forming a crosslinked coating film at 100 ° C. or lower, having good storage stability as an aqueous coating composition, and having high curable retention after storage.

JP 2000-178505 A Japanese Patent No. 3947260 Special table 2003-508562 gazette JP 2006-160936 A JP 2007-45867 A JP 2009-155409 A

  The present invention has been made in view of the above circumstances, can form a crosslinked coating film at a temperature of 100 ° C. or less, is excellent in storage stability as an aqueous coating composition, and has a curability after storage. It aims at providing the manufacturing method of a favorable block polyisocyanate composition.

  As a result of diligent research, the inventor has surprisingly found that a composition containing at least one block polyisocyanate having a specific structure retains low-temperature curability and is stable in storage as an aqueous coating composition. The inventors found that the curability after storage was remarkably improved, and completed the present invention related to the production method.

（式中、Ｒ_１及びＲ_２は、それぞれ独立に炭素数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_１とＲ_２は同一でも、異なっていてもよい。）

（式中、Ｒ_３及びＲ_４は、同一でも異なっていてもよく、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なる群から選ばれる少なくとも１種を含有してもよい炭素数１〜３０個の炭化水素基であって、Ｒ_３及びＲ_４は、互いに結合して５員または６員環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共に、架橋員として付加的に窒素または酸素原子を含有してもよい３員、４員、５員または６員環を形成することができる。）
（２） 第１工程が、ポリイソシアネート（ａ）と活性水素含有親水性化合物（ｄ）との反応後に、マロン酸ジエステル（ｂ）を反応させる工程である、上記（１）項に記載のブロックポリイソシアネート組成物の製造方法。
（３） 第２工程において、有機アミン化合物（ｃ）の１種又は２種以上をポリイソシアネート（ａ）のイソシアネート基に対し５０−５００モル％添加し、第１工程で得られた生成物と反応させる、上記（１）又は（２）項に記載のブロックポリイソシアネート組成物の製造方法。
（４） 第１工程において、マロン酸ジエステル（ｂ）をポリイソシアネート（ａ）のイソシアネート基に対し７５〜１４８モル％添加する、上記（１）〜（３）項のいずれか１項に記載のブロックポリイソシアネート組成物の製造方法。
（５） 第１工程において、活性水素含有親水性化合物（ｄ）をポリイソシアネート（ａ）のイソシアネート基に対し２〜５０モル％添加する、上記（１）〜（４）項のいずれか１項に記載のブロックポリイソシアネート組成物の製造方法。 That is, the present invention has the following configuration.
(1) A malon represented by formula (I) in polyisocyanate (a) having one or more selected from the group consisting of aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates as a skeleton. The acid diester (b) and the active hydrogen-containing hydrophilic compound (d) are added in a total amount of the malonic acid diester (b) and the active hydrogen-containing hydrophilic compound (d) to 77-150 with respect to the isocyanate groups of the polyisocyanate (a). The first step of adding mol% and reacting the polyisocyanate (a) with the malonic acid diester (b) and the active hydrogen-containing hydrophilic compound (d), and the product obtained by the first step and the formula ( II) Production of a block polyisocyanate composition comprising a second step of reacting one or more of the organic amine compounds (c) represented by Manufacturing method.

(In the formula, R ₁ and R ₂ each independently 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 and R ₄ may be the same or different and may contain at least one selected from the group consisting of an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol group. 1-30 hydrocarbon groups, wherein R ₃ and R ₄ are bonded to each other to form a 5- or 6-membered cycloalkyl group, or nitrogen sandwiched between R ₃ and R ₄ (With the atoms, 3-membered, 4-membered, 5-membered or 6-membered rings which may additionally contain nitrogen or oxygen atoms as bridging members can be formed.)
(2) The block according to (1) above, wherein the first step is a step of reacting the malonic acid diester (b) after the reaction between the polyisocyanate (a) and the active hydrogen-containing hydrophilic compound (d). A method for producing a polyisocyanate composition.
(3) In the second step, one or more organic amine compounds (c) are added in an amount of 50 to 500 mol% with respect to the isocyanate group of the polyisocyanate (a), and the product obtained in the first step is The manufacturing method of the block polyisocyanate composition as described in said (1) or (2) term made to react.
(4) In the first step, 75 to 148 mol% of malonic acid diester (b) is added to the isocyanate group of polyisocyanate (a), according to any one of (1) to (3) above. A method for producing a block polyisocyanate composition.
(5) In the first step, 2 to 50 mol% of active hydrogen-containing hydrophilic compound (d) is added to the isocyanate group of polyisocyanate (a), any one of (1) to (4) above The manufacturing method of the block polyisocyanate composition of description.

  According to the present invention, there is provided a method for producing a block polyisocyanate composition capable of forming a crosslinked coating film at a temperature of 100 ° C. or lower and having excellent storage stability and post-storage curability as an aqueous coating composition. be able to.

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.
First, the structure of the block polyisocyanate composition produced by the method of the present invention will be described.
It is estimated that the block polyisocyanate contained in the said block polyisocyanate composition contains what can be represented by following formula (III).

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 used in the production method of the present invention include triisocyanates such as LTI, TTI, and GTI, or derivatives thereof, biuret bonds, urea bonds, isocyanurate bonds, uretdione bonds, urethane bonds, Examples include diisocyanate di- 20-mer oligomers produced by forming allophanate bonds, oxadiazine trione 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（ＩＶ）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 formula (III) is presumed to be represented, for example, as one or more keto bodies represented by the following formula (IV) or enol bodies thereof.

Formula (IV) 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 (IV) 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} formula (IV) 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 the formula (IV) are divided into a structure that exists independently (hereinafter referred to as an independent structure) and a connected structure (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 (IV) in the case of an independent structure may be the same or different, and optionally have an ether bond, ester bond, hydroxyl group, carbonyl group, and thiol group having 1 to 30 carbon atoms. 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 (IV) 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（Ｖ）中、Ｒ_５、Ｒ_６、Ｒ_７、Ｒ_８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（ＩＶ）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 preferred, more preferably 5-membered or 6-membered rings, and still more preferably a structure represented by the following formula (V). 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 (V), R ₅ , R ₆ , R ₇ and R ₈ 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 above formula (IV), it is preferable that at least one of the carbon atoms adjacent to the nitrogen atom is bonded to two or more carbon atoms.

  A block polyisocyanate composition obtained by the production method of the present invention comprises a block polyisocyanate having a keto body represented by the following formula (VI) or an enol body group thereof as a substitute for A in the formula (III). May be included.

(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 (III) presumed to be obtained by the production method of the present invention is from the viewpoint of suppressing crystallization while maintaining low temperature curability. , 50% by mass or less, more preferably 30% by mass or less, more preferably 20% by mass or less, and most preferably 10% by mass or less.

式（ＶＩＩ）におけるＲ_９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 formula (III) is presumed to be one or more structural units represented by the following formula (VII).

R ₉ in formula (VII) is a residue excluding active hydrogen of the active hydrogen-containing compound.

The active hydrogen-containing compound that is a source of R ₉ in formula (VII) 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.

式（ＶＩＩＩ）におけるＲ_１０は、活性水素含有親水性化合物の活性水素を除く残基である。 C in the formula (III) is presumed to be one or more structural units represented by the following formula (VIII).

R ₁₀ in the formula (VIII) is a residue excluding active hydrogen of the active hydrogen-containing hydrophilic compound.

  The active hydrogen-containing hydrophilic compound that is the source of C in formula (III) presumed to be obtained by the production method of the present invention is selected from nonionic hydrophilic compounds, anionic hydrophilic compounds, and cationic hydrophilic compounds. It is. Among these, nonionic hydrophilic compounds and anionic hydrophilic compounds are preferable from the viewpoint of ease of production, and nonionic hydrophilic compounds are more preferable. These hydrophilic compounds may be used alone or in combination of two or more.

  Nonionic hydrophilic compounds include polyethylene glycol compounds having at least three consecutive ethylene oxide groups. Furthermore, the number average molecular weight of the nonionic hydrophilic compound is preferably 200 to 2,000. The lower limit of the number average molecular weight is more preferably 300, still more preferably 400. The upper limit of the number average molecular weight is more preferably 1500, still more preferably 1200, and most preferably 1000. When the lower limit of the number average molecular weight is 200 or more, sufficient water dispersibility of the composition can be obtained. On the other hand, when the upper limit of the number average molecular weight is 2000 or less, it is possible to suppress a decrease in coating properties such as water resistance after baking.

  The exemplified polyethylene glycol compound having at least three consecutive ethylene oxide groups may contain other oxyalkylene groups, specifically oxypropylene groups or oxystyrene groups, in the ethylene oxide repeating unit. good. In this case, the ethylene oxide group molar ratio is preferably 60 mol% or more, more preferably 70 mol% or more, and most preferably 80 mol% or more. A high ethylene oxide group molar ratio is preferable because the compoundability in the water-based paint can be improved efficiently.

Examples of such polyethylene glycol compounds include monoalkoxy polyethylene glycol, polyethylene glycol or triol, so-called pluronic type polypropylene glycol or triol obtained by addition polymerization of ethylene oxide at the end of polypropylene glycol, polyoxypropylene polyoxyethylene copolymer diol or triol. , Polyoxypropylene polyoxyethylene block polymer diol or triol. In particular, monoalkoxy polyethylene glycol and polyethylene glycol are preferable, and monoalkoxy polyethylene glycol is more preferable. Monoalkoxy polyethylene glycol is obtained by adding an alcohol to one end of polyethylene glycol. As monoalcohol which can be used for monoalkoxy polyethyleneglycol, C1-C8 is preferable, More preferably, it is C1-C6, More preferably, it is C1-C4. Most preferred are methanol and ethanol.
Accordingly, among the monoalkoxy polyethylene glycols, monomethoxy polyethylene glycol and monoethoxy polyethylene glycol are preferable, and monomethoxy polyethylene glycol is most preferable.
Among these polyethylene glycol compounds used as the active hydrogen-containing hydrophilic compound, a polyethylene glycol compound in which a monoalcohol having 1 to 4 carbon atoms is added to one end having a number average molecular weight of 200 to 2000 is particularly preferable.

  Specific examples of polyethylene glycol include PEG200, 300, 400, 600, 1000, 2000 manufactured by Nippon Oil & Fats Co., Ltd. Moreover, as monomethoxy polyethylene glycol, Nippon Oil & Fats Co., Ltd. UNIOX M400, 550, 1000, 2000, the product MPG-081 of Nippon Emulsifier Co., Ltd. is mentioned.

  Examples of the anionic hydrophilic compound include a carboxylic acid group-containing compound and a sulfonic acid group-containing compound. Examples of the carboxylic acid group-containing compound include monohydroxycarboxylic acid, dihydroxycarboxylic acid, and derivatives thereof. Among the carboxylic acid group-containing compounds, monohydroxycarboxylic acid or dihydroxycarboxylic acid is preferable, and monohydroxycarboxylic acid is more preferable.

  Specific examples of the carboxylic acid-containing compound include hydroxypivalic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and derivatives such as polycaprolactone diol and polyether polyol using these as initiators. Can be mentioned. When using a carboxylic acid group containing compound, it is preferable to neutralize with a neutralizing agent after manufacture of a block polyisocyanate composition. Examples of the neutralizing agent include tertiary amines such as alkali metals, alkaline earth metals, ammonia, trimethylamine, triethylamine, and dimethylethanolamine.

  Examples of the sulfonic acid group-containing compound include aminoethylsulfonic acid, ethylenediamino-propyl-β-ethylsulfonic acid, 1,3-propylenediamine-β-ethylsulfonic acid, N, N-bis (2-hydroxyethyl) -2. -Aminoethanesulfonic acid. When a sulfonic acid group-containing compound is used, it is preferably neutralized with a neutralizing agent after the production of the block polyisocyanate composition as described above. Examples of the neutralizing agent include tertiary amines such as alkali metals, alkaline earth metals, ammonia, trimethylamine, triethylamine, and dimethylethanolamine.

  When the carboxylic acid group-containing compound is compared with the sulfonic acid group-containing compound, the carboxylic acid group-containing compound is preferred from the viewpoint of ease of production and compoundability in water-based paints.

  Examples of the cationic hydrophilic compound include a hydroxyl group-containing amino compound. Specific examples include dimethylethanolamine, diethylethanolamine, and hydroxypyridine. When using a hydroxyl-containing amino compound, it is preferable to neutralize with a neutralizing agent after manufacture of a block polyisocyanate composition like the above. Examples of the neutralizing agent include organic acids such as acetic acid, propionic acid, butanoic acid, and 2-ethylhexanoic acid.

  The active hydrogen of the active hydrogen-containing hydrophilic compound is exemplified by hydrogen of a hydroxyl group as long as it is a nonionic hydrophilic compound. In the case of hydroxypivalic acid which is an anionic hydrophilic compound, hydrogen of a hydroxyl group is exemplified, and in the case of aminoethylsulfonic acid, hydrogen of an amino group is exemplified. If it is dimethylethanolamine which is a cationic hydrophilic compound, hydrogen of a hydroxyl group is illustrated. That is, the residue excluding active hydrogen of the active hydrogen-containing hydrophilic compound refers to a residue obtained by removing each active hydrogen from a nonionic, anionic, or cationic active hydrogen-containing hydrophilic compound.

  The sum of x, y and z in formula (III) presumed to be obtained by the production method of the present invention is a value corresponding to the average number of isocyanate groups of the polyisocyanate which is the source of R, and is 2.0 to 20 is preferable. The lower limit is more preferably 2.3, still more preferably 2.5, and most preferably 3.0. The upper limit is more preferably 15 and even more preferably 10. Here, x, y, and z mean the statistical average numbers for R of A, B, and C, respectively.

  When the sum of x, y, and z in the formula (III) is 2.0 or more, it is possible to suppress a decrease in crosslinkability and obtain the desired coating film properties. On the other hand, when the total of x, y, and z is 20 or less, the cohesive force is prevented from becoming too high, and a smooth coating film can be obtained. Moreover, neither x nor z is 0. y may be 0, but is more preferably not 0. By not being x = 0, the low-temperature curability and storage stability of the coating liquid composition are kept good. Moreover, generation | occurrence | production of isolation | separation of a coating liquid composition, sedimentation, etc. can be avoided because it is not z = 0.

In the formula (III), x, y, and z are preferably 49 ≧ (x + y) / z ≧ 1. More preferably, the lower limit is 1.5, and more preferably 2.0. In the formula (III), x and y are preferably x / y ≧ 1, more preferably x / y ≧ 1.5, and still more preferably x / y ≧ 2.
In addition, the block polyisocyanate composition obtained by the production method of the present invention includes those in which some isocyanate groups remain. The preferred amount of the remaining isocyanate group varies depending on the purpose of use, but when blended with a polyol or the like and used as a one-pack coating composition, 20 mol% of the isocyanate group before blocking is ensured to ensure storage stability. The content is preferably 10 mol% or less, more preferably 5 mol% or less, and most preferably no residual isocyanate group.

The production method of the present invention will be described in detail.
This production method is represented by the following formula (I) in a polyisocyanate (a) having one or more selected from the group consisting of aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates as a skeleton. The malonic acid diester (b) and the active hydrogen-containing hydrophilic compound (d) are added to the isocyanate group of the polyisocyanate (a) as a total amount of the malonic acid diester (b) and the active hydrogen-containing hydrophilic compound (d). A step of adding ~ 150 mol% and reacting the polyisocyanate (a) with the malonic acid diester (b) and the active hydrogen-containing hydrophilic compound (d); and the product obtained in the first step and the following formula ( It includes two steps of the second step of reacting one or more of the organic amine compounds (c) represented by II).

(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.)

The first step will be described. As a lower limit of the said ratio in a 1st process, it is more preferable that it is 90 mol%, More preferably, it is 95 mol%, Most preferably, it is 100 mol%. The upper limit of the above ratio is more preferably 130 mol%, further preferably 120 mol%, and most preferably 110 mol%. When the ratio of the total amount of the above compounds is 77 mol% or more, deterioration of the low-temperature curability of the composition can be prevented. Moreover, the bad influence with respect to coating film physical properties, such as the water resistance of a baking coating film, can be suppressed because the ratio of the sum total of the said compound is 150 mol% or less. The active hydrogen-containing hydrophilic compound used in the first step has a function of improving the compoundability in the water-based paint.
In the first step, reaction of the isocyanate groups and the active hydrogen-containing hydrophilic compound polyisocyanate (a) (d), to the reaction of the malonic acid diester (b) can be performed simultaneously, either in the reaction previously A second reaction can also be performed after it has been performed. Among them, it is preferable to react with the malonic acid diester (b) after the reaction between the isocyanate group and the active hydrogen-containing hydrophilic compound (d).

  It is preferable that the addition amount of the malonic acid diester (b) in the first step is 75 to 148 mol% with respect to the isocyanate group in the polyisocyanate (a) which is a precursor of the block polyisocyanate. The lower limit of the above ratio is more preferably 88 mol%, still more preferably 98 mol%. By the said ratio being 75 mol% or more, the fall of a crosslinking density can be prevented and desired physical properties, such as the water resistance of a coating film, can be obtained. By the said ratio being 148 mol% or less, the bad influence with respect to coating film physical properties, such as water resistance of a baking coating film, can be suppressed.

  The addition amount of the active hydrogen-containing hydrophilic compound (d) is 2 to 50 mol% based on the number of moles of active hydrogen with respect to the isocyanate group in the polyisocyanate (a) which is a precursor of the block polyisocyanate. Is preferred. As an upper limit of the said ratio, 40 mol% is more preferable, More preferably, it is 35 mol%. When the ratio is 2 mol% or more, sufficient water dispersibility of the composition can be obtained. Moreover, when the said ratio is 50 mol% or less, the fall of a crosslinking density can be suppressed and desired physical properties, such as the water resistance of a coating film, can be obtained.

  The active hydrogen-containing hydrophilic compound (d) in the first step is selected from the aforementioned nonionic hydrophilic compounds, anionic hydrophilic compounds, and cationic hydrophilic compounds. Among these, nonionic hydrophilic compounds and anionic hydrophilic compounds are preferable from the viewpoint of ease of production, and nonionic hydrophilic compounds are more preferable. These hydrophilic compounds may be used alone or in combination of two or more.

The malonic acid diester (b) in the first step is represented by the formula (I). 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. . 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, y, z in formula (III) presumed to be obtained by the present invention is as follows: active hydrogen-containing hydrophilic compound (d) with respect to isocyanate group in polyisocyanate (a) in the first step, malonic acid diester It depends on the mol% added (b) and the reaction rate. However, when the block polyisocyanate composition synthesized in another reaction vessel is finally mixed, it also depends on the mixing ratio. The composition ratio of x, y, z is not only the addition mol% of the active hydrogen-containing hydrophilic compound (d) and malonic acid diester (b) to the isocyanate group in the polyisocyanate (a) in the first step, but also the reaction Since it depends on the rate, it is preferable to confirm the isocyanate residual rate at the end of the first step before the second 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 second step will be described. The addition amount of the organic amine compound (c) represented by the formula (II) 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, the storage stability can be kept high, and when it is 500 mol% or less, the amount of free amine is reduced and coloring of the baked 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, it is estimated that B in Formula (III).
In the first step, when the total amount of the malonic acid diester (b) and the active hydrogen-containing hydrophilic compound (d) relative to the isocyanate group in the polyisocyanate (a) is added in an amount exceeding 100 mol%, the first Malonic acid diester (b) may remain after completion of the process. In that case, a part of the 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 (II). Specifically, in the organic amine compound (c) represented by the formula (II), 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 (II) may be the same or different, 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 formula (II), 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_５、Ｒ_６、Ｒ_７、Ｒ_８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（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。

In formula (X), R ₅ , R ₆ , R ₇ and R ₈ 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 (II), at least one of the carbon atoms adjacent to the nitrogen atom is bonded to two or more carbon atoms. ,preferable.

  In the second step, the above-described chain amine compound and the cyclic amine compound containing a nitrogen atom can be used alone, or two or more kinds can be used in combination. 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 of the second step, 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, as the third step, the remaining organic amine compound and / or the reaction of the ester group of the reaction product of the polyisocyanate and malonic acid diester produced in the first step with the organic amine compound (ie, the second step) In order to reduce the amount of the alcohol compound dissociated by the reaction in the step), removal purification and the like may be performed.
The organic amine compound (c) remaining after the reaction in the second step is, for example, 20 to 80 ° C. under reduced pressure in order to improve the storage stability (inhibition of gas generation amount and suppression of change in coating solution pH) as a coating composition. It is preferable to carry out removal purification by heating or the like 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. In this case, the number of moles of the blocked isocyanate group indicates the number of moles based on the isocyanate group serving as the source of the partial structure of A and B in the polyisocyanate as a precursor.

  The alcohol compound dissociated by the reaction between the ester group of the polyisocyanate and malonic acid diester produced in the first step and the organic amine compound is also stable in storage as a coating composition (inhibition of gas generation amount, coating). In order to improve (liquid pH change suppression), it is preferable to reduce the residual amount like the remaining organic amine compound. 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.

  To the block polyisocyanate composition obtained by the production method of the present invention, a block polyisocyanate derived from an existing active methylene-based, oxime-based, amine-based, or pyrazole-based blocking agent alone or from two or more blocking agents is added. It can also be used by mixing.

  However, when a large amount of existing active methylene block polyisocyanate is mixed, the storage stability of the coating composition may be lowered. Further, when a large amount of oxime block polyisocyanate, amine block polyisocyanate, and pyrazole block polyisocyanate is mixed, the low temperature curability may be lowered. Therefore, the mixing amount of the block polyisocyanate other than the block polyisocyanate according to the formula (III) is considered to be preferably 20% by mass or less with respect to the total amount of the block polyisocyanate, more preferably 10% by weight or less, Preferably it is 5 mass% or less.

  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 obtained by the production method 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 obtained by the production method of the present invention is 100 to 1,000 mPa · s / 25 ° C. with 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. .

  The acid dissociation constant (PKa) is 7.0 to 8.8 with respect to the blocked isocyanate group of the blocked polyisocyanate composition in order to improve the storage stability (inhibition of gas generation amount, suppression of change in coating solution pH) as the coating composition. It is preferable to mix 10 mol% or more of the basic compound (e) 5. 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, it was a surprising result that the storage stability as a coating composition was greatly improved while the low temperature curability was maintained, and the curability retention after storage was high.

  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 is more preferably 8.3, and more preferably 8.0. If the PKa of the basic compound is 7.0 or more, it is preferable because the storage stability is improved, and if it is 8.5 or less, the pH at the time of blending the paint is not too high.

  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%. In this case, the number of moles of the blocked isocyanate group indicates the number of moles based on the isocyanate group serving as the source of the partial structure of A and B in the polyisocyanate as a 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 is preferably added after the first step and the second step are completed, and the first step and the second step. More preferably, after the third step is completed.

  By using the block polyisocyanate composition obtained by the production method of the present invention as a coating composition, storage stability and curability after storage can be significantly improved while maintaining low-temperature curability. 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 block polyisocyanate composition obtained by the production method of the present invention is considered to be greatly different in that it has the structure of A in formula (III).

  The block polyisocyanate composition obtained by the production method of the present invention forms a coating composition by blending with at least one of polyol, polyamine and alkanolamine. Furthermore, in order to improve the storage stability when blended with a polyol, the block polyisocyanate composition 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.

  Depending on the purpose of improving the compoundability in the water-based coating composition, a surfactant, a solvent having a tendency to be miscible with water, or the like may be used for the block polyisocyanate composition. Specific examples of surfactants include anions such as aliphatic soaps, rosin acid soaps, alkyl sulfonates, dialkylaryl sulfonates, alkylsulfosuccinates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl aryl sulfates, and the like. Nonionic surfactants such as a reactive surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, and polyoxyethylene oxypropylene block copolymer. Solvents that tend to be miscible with water include diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, isobutanol, butyl glycol, and N-methylpyrrolidone. Butyl diglycol or butyl diglycol acetate.

  Among these solvents, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, isobutanol, butyl glycol, N-methylpyrrolidone, and butyl diglycol are preferable, and diethylene glycol dimethyl ether is more preferable. Diethylene glycol diethyl ether, propylene glycol dimethyl ether, and dipropylene glycol dimethyl ether are preferred. These solvents may be used alone or in combination of two or more. Further, esters such as ethyl acetate, acetic acid-n-butyl and cellosolve acetate are not preferable because the solvent itself may be hydrolyzed during storage.

  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.

  When the block polyisocyanate composition and the polyol obtained by the production method of the present invention are used in a water-based coating composition, the blending method of the block polyisocyanate composition and the polyol involves mixing and dispersing the block polyisocyanate composition in the polyol as it is. Alternatively, the block polyisocyanate composition may be once mixed with water and then mixed with the polyol.

  It is preferable that pH of the water-based coating composition containing the block polyisocyanate composition obtained by the manufacturing method of this invention is 7.0-9.0. The lower limit thereof is more preferably 7.5, still more preferably 8.0, and the upper limit thereof is more preferably 8.8, further preferably 8.6. It is preferable that the pH of the water-based coating composition is 7.0 to 9.0 because the stability of additives such as pigments such as aluminum and rheology control agents can be maintained.

  The basic compound (e) of PKa 7.0 to 8.5 may be added at the time of blending the water-based 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%. In the present invention, the weakly basic compound (e) is added in an amount of 20 mol% or more in the total basic composition, so that it is in excess of the formation of a neutral salt of the total acidic content present in each component in the coating. Is also preferable because the pH of the prepared coating composition does not become too high. 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 obtained by the production method 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 may be an antioxidant such as hindered phenol, an ultraviolet absorber such as benzotriazole or benzophenone, a pigment such as titanium oxide, carbon black, indigo, quinacridone, pearl mica, or a metal powder pigment such as Aluminum and the like, rheology control agents such as hydroxyethyl cellulose, urea compounds, microgels, etc., and hardening accelerators such as tin compounds, zinc compounds, amine compounds and the like 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 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 cross-linked coating film formed from this coating composition is used between layers when performing layer coating or recoating in addition to chemical resistance, heat resistance, water resistance, etc., which are the characteristics of general urethane cross-linked coating films. It is possible to form a hydrogen bond, and the adhesion between layers is excellent. Even in the coating film in which the crosslinked structure is not completely formed after the baking step, 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.
Also, when laminating several layers of coating liquid wet-on-wet as in the coating of a new car line of an automobile, an organic amine compound is present in the coating composition or in the crosslinked coating after curing, so that the lower layer or It may also act as a catalyst for the upper layer crosslinking reaction.

  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 for quantifying 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 represented by A in formula (III). And expressed as mass% of the isocyanate group derived from B, and is calculated by the following formula.
{(Solid content (mass%) of block polyisocyanate composition) x (mass of polyisocyanate used in reaction x isocyanate group content% as source of partial structure of A and B among precursor polyisocyanates)} / (Resin mass of blocked polyisocyanate composition after blocking reaction)
When diluted with a solvent or the like, the value in the diluted state is described.

(Ratio of x, y, z of block polyisocyanate)
-Composition ratio of z It calculated by measuring the residual mol% of an isocyanate group by the infrared vector measurement before and behind reaction of an active hydrogen containing hydrophilic compound.
-Composition ratio of x, y When p ≠ 0, the organic amine compound reacts preferentially with the remaining isocyanate groups, and therefore the amount of the organic amine compound needs to be taken into consideration from the reaction amount of the organic amine compound. Therefore, it calculated as x = {(q * r) -p}, y = (100- (x + z)) (the definition of p, q, r is as above-mentioned). The residual mole% of isocyanate groups after the malonic acid diester reaction is quantified by infrared spectrum measurement of the reaction solution, and the reaction rate of the organic amine compound is quantified by gas chromatographic measurement of the amount of the organic amine compound reduced 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 in the keto form of A of formula (IV), which is the product after the second step, was observed in the vicinity of 4.5 ppm, and the proton in the enol form was observed in the vicinity of 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.

(Appearance of coating liquid)
The coating liquid to which each component was added was allowed to stand at room temperature for 2 hours, and the state after the standing was observed with the naked eye. In the case of emulsification, dispersion or dissolution, ◯, in part, the state of dispersion changed, and the whitening of the coating solution progressed, and Δ if there was an abnormality such as separation or sedimentation.

(PH setting when coating liquid is blended)
When blending the coating liquid (water-based coating composition), ○ that can adjust the pH of the coating liquid to 8.5 with dimethylethanolamine, x that cannot be adjusted as such, and when dimethylethanolamine is not added Also, the case where the pH of the obtained coating liquid exceeded 9.0 was evaluated as x.

(Coating solution pH change before and after storage)
The coating solution pH at the time of preparing the initial coating solution was adjusted to 8.5. When the difference from the initial pH of the coating solution after storage at 40 ° C. for 10 days is within 0.2, ◎◎, when it exceeds 0.2 and within 0.4, ◎, and exceeds 0.4 when 0.4. The case of 6 or less was marked as ◯, the case of exceeding 0.6 and within 0.9, Δ, the case of exceeding 0.9 and within 1.2 as x, and the case of exceeding 1.2 as xx.

(Gas generation test during storage)
30 mmol of the block polyisocyanate composition was taken as an effective NCO group, and water was added thereto so that the total solution mass was 200 g, to obtain a test solution. Transfer the solution to a 300 cc Erlenmeyer flask, and fix it with the tip of a measuring pipette fixed with a silicone rubber scissor 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 is 100), monomethoxypolyethylene glycol having a number average molecular weight of 400 (trade name “Uniox M400” of NOF Corporation), 42.3 parts by mass (corresponding to 20 mol% of isocyanate groups in polyisocyanate), 117.1 parts by mass of diethylene glycol dimethyl ether was charged and held at 80 ° C. for 6 hours. Thereafter, the reaction solution temperature was cooled to 60 ° C., 72.0 parts by mass of diethyl malonate (corresponding to 85 mol% of the isocyanate group in polyisocyanate), 0.88 parts by mass of 28% methanol solution of sodium methylate, After holding for 4 hours, 0.86 parts by mass of 2-ethylhexyl acid phosphate was added. Thereafter, 45.5 parts by mass of diisopropylamine (corresponding to 85 mol% of the isocyanate group in the polyisocyanate) was added, and the temperature of the reaction solution was raised to 70 ° C. and held for 5 hours. This reaction solution was analyzed by gas chromatography, and it was confirmed that the reaction rate of diisopropylamine was 70%. Thereafter, 14.2 parts by mass of n-butanol was added to obtain a block polyisocyanate composition having a solid content concentration of 60% by mass. Table 1 shows the physical properties of the resulting blocked polyisocyanate composition and the structure of formula (III) of the blocked polyisocyanate.

(Example 2-15) (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 resulting blocked polyisocyanate composition and the structure of formula (III) of the blocked polyisocyanate.

(Comparative 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 composition obtained in Production Example 1 (the polyisocyanate in this case) The number of moles of isocyanate groups is 100), monomethoxypolyethylene glycol having a number average molecular weight of 680 (trade name “MPG-081” by Nippon Emulsifier Co., Ltd.) 71.9 parts by weight (corresponding to 20 mole% of isocyanate groups in polyisocyanate) ), 137.6 parts by mass of diethylene glycol dimethyl ether were charged and held at 80 ° C. for 6 hours. Thereafter, 84.6 parts by mass of diisopropyl malonate (corresponding to 85 mol% of the isocyanate group in polyisocyanate) and 1.06 parts by mass of a 28% methanol solution of sodium methylate were added and held for 4 hours, and then 2-butanol. 24.5 parts by mass was added and held for another 2 hours. Thereafter, as a result of measuring the infrared spectrum, it was confirmed that the isocyanate group had disappeared, and subsequently, 1.03 parts by mass of 2-ethylhexyl acid phosphate was added to obtain a block polyisocyanate composition having a solid content concentration of 60% by mass. Table 1 shows the physical properties of the resulting blocked polyisocyanate composition and the structure of formula (III) of the blocked 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 composition obtained in Production Example 1 (the polyisocyanate in this case) The number of moles of isocyanate groups is 100), monomethoxypolyethylene glycol having a number average molecular weight of 680 (trade name “MPG-081” by Nippon Emulsifier Co., Ltd.) 71.9 parts by weight (corresponding to 20 mole% of isocyanate groups in polyisocyanate) ), 116.2 parts by mass of diethylene glycol dimethyl ether were charged and held at 80 ° C. for 6 hours. Thereafter, the temperature of the reaction solution was cooled to 60 ° C., and 41.7 parts by mass of 3,5-dimethylpyrazole (corresponding to 82 mol% of isocyanate groups in polyisocyanate) was added in 5 portions. After completion of the addition, the mixture was stirred for 1 hour, and then the infrared spectrum was measured. As a result, the disappearance of the isocyanate group was confirmed. Thereafter, 24.5 parts by mass of isobutanol was added to obtain a block polyisocyanate composition having a solid concentration of 60% by mass. Table 1 shows the physical properties of the resulting blocked polyisocyanate composition and the structure of formula (III) of the blocked 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 1 (the polyisocyanate in this case) 4) 42.3 parts by mass of a monomethoxypolyethylene glycol having a number average molecular weight of 400 (trade name “Uniox M400” from NOF Corporation) (equivalent to 20 mol% of isocyanate groups in polyisocyanate) ), 130.3 parts by mass of diethylene glycol dimethyl ether were charged and held at 80 ° C. for 6 hours. Thereafter, the reaction liquid temperature was cooled to 60 ° C., 33.9 parts by mass of diethyl malonate (corresponding to 40 mol% of the isocyanate group in polyisocyanate), 0.72 parts by mass of 28% methanol solution of sodium methylate, After holding for 4 hours, 0.70 parts by mass of 2-ethylhexyl acid phosphate was added. Thereafter, 21.4 parts by mass of diisopropylamine (corresponding to 40 mol% of the isocyanate group in polyisocyanate) was added, and the temperature of the reaction solution was raised to 70 ° C. and held for 5 hours. This reaction solution was analyzed by gas chromatography, and it was confirmed that ethanol and disisopropylamine were not present. Table 1 shows the physical properties of the resulting blocked polyisocyanate composition and the structure of formula (III) of the blocked 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 Residues excluding active hydrogen in the compounds listed in <> * 6 DMDG: Diethylene glycol dimethyl ether * 7 Uniox M400 (monomethoxy polyethylene glycol having a number average molecular weight of 400: trade name of Nippon Oil & Fat Co., Ltd. M400 "))
* 8 DEM: diethyl malonate (R1: ethyl group, R2: ethyl group)
* 9 DIPA: diisopropylamine (R3: isopropyl group, R4: isopropyl group)
* 10 DMDP: Dipropylene glycol dimethyl ether * 11 UNIOX M550 (monomethoxy polyethylene glycol having a number average molecular weight of 550: trade name of Nippon Oil & Fats Co., Ltd. ("M550" in the table))
* 12 DNBA: di-n-butylamine (R3: n-butyl group, R4: n-butyl group)
* 13 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. * 14 UNIOX M1000 (monomethoxypolyethylene glycol having a number average molecular weight of 1000: Nippon Oil & Fats Trade name of the corporation (“M1000” in the table))
* 15 DIPM: Diisopropyl malonate (R1: isopropyl group, R2: isopropyl group)
* 16 ECHA: N-ethylcyclohexylamine (R3: ethyl group, R4: cyclohexyl group)
* 17 N75BA (75% butyl acetate solution of biuret-type polyisocyanate of hexamethylene diisocyanate: trade name of Bayer)
* 18 ME20-100 (urethane of hexamethylene diisocyanate and polyol, allophanate type polyisocyanate: trade name of Asahi Kasei Chemicals Corporation)
* 19 MPG-081 (monomethoxy polyethylene glycol having a number average molecular weight of 680: trade name of Nippon Emulsifier Co., Ltd.)
* 20 DMM: dimethyl malonate (R1: methyl group, R2: methyl group)
* 21 VESTANAT T1890E (70% butyl acetate solution of isocyanurate-type polyisocyanate of isophorone diisocyanate: trade name of Evonik Degussa (“T1890E” in the table))
* 22 Coronate L (75% ethyl acetate solution of urethane type polyisocyanate of tolylene diisocyanate and trimethylolpropane: trade name of Nippon Polyurethane Industry Co., Ltd.)
* 23 Mixture of residues excluding active hydrogen of diethyl malonate and residues excluding active hydrogen of diisopropylamine * 24 HPA: hydroxypivalic acid * 25 Cyclic amine compound DIPA and cyclic amine compound containing nitrogen atom Mixture of R3 and R4 derived from 2,2,6,6-tetramethylpiperidine * 26 PLACCEL 205BA (2,2-dimethylolbutanoic acid derivative: trade name of Daicel Chemical Industries, Ltd. ("205BA" in the table))
* 27 R3 and R4 derived from 2,6-dimethylpiperidine, a cyclic amine compound containing a nitrogen atom
* 28 MPG (250) (monomethoxy polyethylene glycol having a number average molecular weight of 250)

(Example 16) (Evaluation of Block Polyisocyanate Composition)
Acrylic emulsion as main ingredient (hydroxyl value per resin 40 mg KOH / g, acid value per resin 13 mg KOH / resin g, Tg 20 ° C., number average molecular weight 100,000, resin concentration 42 mass%, adjusted to pH 8.5 with dimethylethanolamine. 100 parts by mass and 8.45 parts by mass of the block polyisocyanate composition obtained in Example 1 (the ratio of the hydroxyl equivalent molar equivalent G of the main agent to the molar equivalent H of effective NCO groups of the block polyisocyanate composition is H / G = 0.3) and 26.0 parts by weight of water were blended (adjusted so that the solid content of the paint was 35% by mass). Further, final adjustment was performed while adding dimethylethanolamine so that the pH of the coating solution was 8.5. The prepared coating solution was allowed to stand at room temperature for 2 hours and the appearance of the coating solution was observed. After drying, an applicator was applied to 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.

  After preparing this coating solution, it was stored at 40 ° C. for 10 days, and after storage, it was coated in the same manner as described above, and the gel fraction after storage was measured. The results of the gel fraction retention after storage are shown in Table 2. Further, the pH of the coating solution after storage at 40 ° C. for 10 days was measured. Further, 28.0 g of the block polyisocyanate composition obtained in Example 1 (corresponding to 30 mmol as an effective NCO group) and 172.0 g of water (added so that the total mass becomes 200.0 g) were blended, An aqueous solution of an isocyanate composition was obtained. The amount of gas (carbon dioxide) generated during storage of this aqueous solution at 40 ° C. for 10 days was measured. The results are shown in Table 2.

(Examples 17-30, Reference Example 1, Comparative Example 4-6) (Evaluation of Block Polyisocyanate Composition)
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 evaluation results of the obtained block polyisocyanate composition.

The comment on the * part in Table 2 is as follows.
* 29 Acrylic emulsion (resin concentration 42% by mass, hydroxyl value per resin 40 mg KOH / g, Tg 20 ° C., number average molecular weight 100,000)
* 30 The production method and physical properties of the block polyisocyanate composition used here are as follows. That is, the inside of a four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was put in a nitrogen atmosphere, and 100 parts by mass of the polyisocyanate obtained in Production Example 1 (the polyisocyanate in this case) The number of moles of isocyanate group is 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 group in 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 (effective NCO group mass%: 6.2 mass%) having a solid content concentration of 60 mass%. Separately, this block polyisocyanate composition was transferred to an eggplant flask, and was evaporated under reduced pressure at 60 ° C. and 10 hPa for 60 minutes using an evaporator. After removing most of the solvent, NMR measurement was performed. . As a result, x / y = 2.4. Moreover, the keto body / enol body composition ratio of the A component was 99/1.
* 31 Since the coating liquid separated in Reference Example 1, the physical properties were not evaluated.

(Example 31) (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 is 100), monomethoxypolyethylene glycol having a number average molecular weight of 400 (trade name “Uniox M400” of NOF Corporation), 42.3 parts by mass (corresponding to 20 mol% of isocyanate groups in polyisocyanate), 107.1 parts by mass of diethylene glycol dimethyl ether was charged and maintained at 80 ° C. for 6 hours. Thereafter, the reaction solution temperature was cooled to 60 ° C., 72.0 parts by mass of diethyl malonate (corresponding to 85 mol% of the isocyanate group in polyisocyanate), 0.88 parts by mass of 28% methanol solution of sodium methylate, After holding for 4 hours, 0.86 parts by mass of 2-ethylhexyl acid phosphate was added. Thereafter, 45.5 parts by mass of diisopropylamine (corresponding to 85 mol% of the isocyanate group in the polyisocyanate) was added, and the temperature of the reaction solution was raised to 70 ° C. and held for 5 hours. This reaction solution was analyzed by gas chromatography, and it was confirmed that the reaction rate of diisopropylamine was 70%. Thereafter, this reaction solution was transferred to an eggplant flask, and distilled under reduced pressure for 30 minutes at 60 ° C. and a reduced pressure of 10 hPa using an evaporator. As a result of gas chromatography analysis, the amount of diisopropylamine remaining was 2 It was confirmed that 0.1 part by mass (corresponding to 5 mol% with respect to the blocked isocyanate group) and the remaining ethanol was 1.0 part by mass (corresponding to 5 mol% with respect to the blocked isocyanate group). 24.2 parts by mass of N-ethylmorpholine (corresponding to 50 mol% with respect to the blocked isocyanate group) and diethylene glycol dimethyl ether were added to obtain a block polyisocyanate composition having a solid content concentration of 60% by mass. Table 3 shows the physical properties of the resulting block polyisocyanate composition.

(Examples 32-42, Comparative Example 7, Reference Example 2-3) (Production of Block Polyisocyanate Composition)
The same procedure as in Example 31 was performed except that the components and ratios shown in Table 3 were used. Table 3 shows the physical properties of the resulting block polyisocyanate composition.

表３中における＊部の注解は、以下のとおりである。表３中において、表１と同一の略語については、同一の意味である。
＊１ 第１工程で生成したポリイソシアネートとマロン酸ジエステルの反応生成物のエステル基と有機アミン化合物の反応により解離したアルコール化合物の残存量
＊２ ブロックイソシアネート基に対するモル％
＊３ ＮＥＭＯ：Ｎ−エチルモルホリン Ｐｋａ：７．７
＊４ ＴＥＡ：トリエタノールアミン Ｐｋａ：７．８
＊５ 鎖状アミン化合物であるＤＮＢＡと窒素原子を含む環状アミン化合物である２，６−ジメチルピペリジン由来のＲ３、Ｒ４の混合
＊６ ＮＭＭＯ：Ｎ−メチルモルホリン Ｐｋａ：７．４
＊７ ２ＭＩＭ：２−メチルイミダゾール Ｐｋａ：７．８
＊８ ＩＭ：イミダゾール Ｐｋａ：７．０
＊９ ＭＯ：モルホリン Ｐｋａ：８．４
＊１０ 鎖状アミン化合物であるＤＩＰＡと窒素原子を含む環状アミン化合物である２，２，６，６−テトラメチルピペリジン由来のＲ３、Ｒ４の混合
＊１１ ＤＭＥＡ：ジメチルエタノールアミン Ｐｋａ：９．４
＊１２ ピリジン Ｐｋａ：５．４

The comment on the * part in Table 3 is as follows. In Table 3, the same abbreviations as in Table 1 have the same meaning.
* 1 Residual amount of 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 * 2 mol% relative to the blocked isocyanate group
* 3 NEMO: N-ethylmorpholine Pka: 7.7
* 4 TEA: Triethanolamine Pka: 7.8
* 5 Mixture of DNBA, a linear amine compound, and R3, R4 derived from 2,6-dimethylpiperidine, a cyclic amine compound containing a nitrogen atom. * 6 NMMO: N-methylmorpholine Pka: 7.4
* 7 2MIM: 2-methylimidazole Pka: 7.8
* 8 IM: Imidazole Pka: 7.0
* 9 MO: Morpholine Pka: 8.4
* 10 Mixture of DIPA as a chain amine compound and R3 and R4 derived from 2,2,6,6-tetramethylpiperidine as a cyclic amine compound containing a nitrogen atom. * 11 DMEA: Dimethylethanolamine Pka: 9.4
* 12 Pyridine Pka: 5.4

(Example 43) (Evaluation of Block Polyisocyanate Composition)
Acrylic emulsion as main ingredient (hydroxyl value per resin 40 mg KOH / g, acid value 13 mg KOH / g per resin, Tg 20 ° C., number average molecular weight 100,000, resin concentration 42 mass%, adjusted to pH 8.5 with dimethylethanolamine) ) 100 parts by mass and 14.0 parts by mass of the block polyisocyanate composition obtained in Example 31 (the ratio between the molar equivalent A of effective NCO groups of the block polyisocyanate composition and the hydroxyl molar equivalent B of the main component is A / B = 0.5) and 30.0 parts by weight of water were blended (adjusted so that the solid content of the paint was 35% by mass). Further, final adjustment was performed while adding dimethylethanolamine so that the pH of the coating solution was 8.5. The prepared coating solution was allowed to stand at room temperature for 2 hours and the appearance of the coating solution was observed. After drying, an applicator was applied to 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 4. After blending this paint, it was stored at 40 ° C. for 10 days and then coated in the same manner as described above, and the gel fraction after storage was measured. The results of the gel fraction retention after storage are shown in Table 4. Further, the pH of the coating liquid after storage at 40 ° C. for 10 days was measured, and the results are shown in Table 4.

  Further, 28.0 g of the block polyisocyanate composition obtained in Example 31 (corresponding to 30 mmol as an effective NCO group) and 172.0 g of water (added so that the total mass becomes 200.0 g) were blended, and the block An aqueous solution of the polyisocyanate composition was obtained. The amount of gas (carbon dioxide) generated during storage of this aqueous solution at 40 ° C. for 10 days was measured. The results are shown in Table 4.

(Reference Example 5) (Evaluation of Block Polyisocyanate Composition)
Acrylic emulsion as main ingredient (hydroxyl value per resin 40 mg KOH / g, acid value 13 mg KOH / g per resin, Tg 20 ° C., number average molecular weight 100,000, resin concentration 42 mass%, adjusted to pH 8.5 with dimethylethanolamine) ) 100 parts by mass and 8.6 parts by mass of the block polyisocyanate composition obtained in Reference Example 2 (the ratio of the molar equivalent A of the effective NCO group of the block polyisocyanate composition to the hydroxyl molar equivalent B of the main component is A / B = 0.3) and 26.1 parts by weight of water (adjusted so that the solid content of the paint is 35% by mass). When the pH of the coating liquid was measured at this point, it was already 9.6, and the pH of the coating liquid could not be adjusted to 8.5. The prepared coating solution was allowed to stand at room temperature for 2 hours and the appearance of the coating solution was observed. After drying, an applicator was applied to 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 4. After blending this paint, it was stored at 40 ° C. for 10 days and then coated in the same manner as described above, and the gel fraction after storage was measured. The results of the gel fraction retention after storage are shown in Table 4. Further, the pH of the coating liquid after storage at 40 ° C. for 10 days was measured, and the results are shown in Table 4. The pH change in this case was measured as the amount of change from the initial value in the same manner as in Example 43. However, since the initial value is different (greater than 8.5), it is indicated by ().

  Further, 28.6 g of the block polyisocyanate composition obtained in Reference Example 2 (corresponding to 30 mmol as an effective NCO group) and 171.4 g of water (added so that the total mass becomes 200.0 g) are blended, and the block An aqueous solution of the polyisocyanate composition was obtained. The amount of gas (carbon dioxide) generated during storage of this aqueous solution at 40 ° C. for 10 days was measured. The results are shown in Table 4.

(Examples 44-54, Reference Examples 4 and 6, Comparative Example 8) (Evaluation of Block Polyisocyanate Composition)
The same procedure as in Example 43 was performed except that the components and ratios shown in Table 4 were used. The evaluation results of the obtained block polyisocyanate composition are shown in Table 4.

The comment on the * part in Table 4 is as follows.
* 13 Acrylic emulsion (resin concentration 42% by mass, medium: water, hydroxyl value 40 mgKOH / g per resin, acid value 13 mgKOH / g per resin, Tg 20 ° C., number average molecular weight 100,000)
* 14 Acrylic polyol (resin concentration 60 mass%, solvent: DMDG, hydroxyl value per resin 80 mg KOH / g, acid value 47 mg KOH / g per resin, Tg 30 ° C., number average molecular weight 7,400)
* 15 Since the pH at the time of blending the coating liquid was higher than 8.5 and the pH could not be adjusted to 8.5 using dimethylethanolamine, the initial value for pH change measurement was the relevant pH (above 8.5). The results are shown in ().

  The block polyisocyanate composition obtained by the production method of the present invention can be cross-linked at a baking temperature of 100 ° C. or less from the results of the above Examples, Comparative Examples and Reference Examples, and is stable in storage as an aqueous coating composition. It was found that the properties (pH change, gas generation, curability after storage, etc.) are excellent.

  The block polyisocyanate composition obtained by the production method of the present invention can be suitably used as a coating composition having excellent low-temperature curability and post-storage curability.

Claims (5)

A malonic acid diester represented by the formula (I) is added to a polyisocyanate (a) having one or more selected from the group consisting of an aliphatic polyisocyanate, an alicyclic polyisocyanate, and an aromatic polyisocyanate as a skeleton. b) and an active hydrogen-containing hydrophilic compound (d) are added in a total amount of malonic acid diester (b) and active hydrogen-containing hydrophilic compound (d) in an amount of 77 to 150 mol% based on the isocyanate groups of polyisocyanate (a). In the first step of reacting the polyisocyanate (a) with the malonic acid diester (b) and the active hydrogen-containing hydrophilic compound (d), the product obtained in the first step and the formula (II) A process for producing a block polyisocyanate composition comprising a second step of reacting one or more of the organic amine compounds (c) shown

(In the formula, R ₁ and R ₂ each independently 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 and R ₄ may be the same or different and may contain at least one selected from the group consisting of an ether bond, an ester bond, a hydroxyl group, a carbonyl group, and a thiol group. 1-30 hydrocarbon groups, wherein R ₃ and R ₄ are bonded to each other to form a 5- or 6-membered cycloalkyl group, or nitrogen sandwiched between R ₃ and R ₄ (With the atoms, 3-membered, 4-membered, 5-membered or 6-membered rings which may additionally contain nitrogen or oxygen atoms as bridging members can be formed.)   The block polyisocyanate composition according to claim 1, wherein the first step is a step of reacting the malonic acid diester (b) after the reaction between the polyisocyanate (a) and the active hydrogen-containing hydrophilic compound (d). Production method.   In the second step, one or more of the organic amine compound (c) is added in an amount of 50 to 500 mol% based on the isocyanate group of the polyisocyanate (a), and reacted with the product obtained in the first step. The manufacturing method of the block polyisocyanate composition of Claim 1 or 2.   The block polyisocyanate composition according to any one of claims 1 to 3, wherein in the first step, 75 to 148 mol% of malonic acid diester (b) is added to the isocyanate group of polyisocyanate (a). Method.   The block polyisocyanate composition according to any one of claims 1 to 4, wherein 2 to 50 mol% of the active hydrogen-containing hydrophilic compound (d) is added to the isocyanate group of the polyisocyanate (a) in the first step. Manufacturing method.