JP7593033B2 - Blocked isocyanate composition - Google Patents

Description

The present invention relates to a blocked isocyanate composition containing a blocked isocyanate compound, which is a blocked (meth)acrylic acid ester having an isocyanato group, and a stabilizer.

A blocked isocyanate compound is a compound in which an isocyanato group is reacted with an active hydrogen group-containing compound (blocking agent) to inactivate (block) the reactivity of the isocyanato group. When this compound is heated, the blocking agent dissociates and the isocyanato group is regenerated. For example, when using a blocked isocyanate compound as a curing agent, by blocking the isocyanate group, it is not necessary to prepare a two-liquid type, for example, one liquid containing a base agent having an active hydrogen group and another liquid containing a compound having an isocyanato group for reacting with the active hydrogen group, and it is possible to premix the base agent having an active hydrogen group and the blocked isocyanate compound into one liquid. For this reason, blocked isocyanate compounds are widely used in adhesives, coating agents, molding materials, etc.

Cited Document 1 discloses a urethane-formation reaction catalyst used in a urethane-formation reaction between an isocyanate or a blocked isocyanate and a polyol, the urethane-formation reaction catalyst comprising the following components (A), (B), and (C), in which component (A) is in a uniformly dissolved state in component (C):
(A) an acetylacetone compound of at least one specific metal element selected from the group consisting of zinc, aluminum, calcium, zirconium, and magnesium; (B) a stabilizer; and (C) a solvent.

Cited Document 2 discloses a polyaniline composition that contains a polyaniline complex in which a substituted or unsubstituted polyaniline molecule is doped with a proton donor, a phenolic compound, a divalent blocked isocyanate compound, and a solvent.

JP 2015-136678 A JP 2012-158620 A

In conventional blocked isocyanate compositions, the decomposition of the blocked isocyanate compound proceeds gradually in a solution, particularly in a solution in which a hydroxyl group, an amino group, or a thiol group coexists with the blocked isocyanate compound, and therefore the storage stability of the blocked isocyanate compound in the blocked isocyanate composition is poor. For this reason, there has been a demand for an improvement in the storage stability of the blocked isocyanate compound in the blocked isocyanate composition. There has also been a demand for a cured film in which the blocked isocyanate composition has been well cured while maintaining the storage stability of the blocked isocyanate compound in the blocked isocyanate composition, and further for a method for producing a composition containing an isocyanate compound, which causes the blocking agent to be released from the blocked isocyanate compound in the blocked isocyanate composition.

The present invention has been made to solve the above problems, and aims to provide a method for producing a blocked isocyanate composition having excellent storage stability of the blocked isocyanate compound, a cured film obtained by curing the blocked isocyanate composition, and a composition containing an isocyanate compound, etc., by removing a blocking agent from the blocked isocyanate compound, etc. in the blocked isocyanate composition.

As a result of intensive research into the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a specific stabilizer, which is a salt of a specific blocked isocyanate compound with an acid having a pKa of 2.0 or less, and have completed the present invention. That is, the present invention includes, for example, the following aspects [1] to [10].
[1] A blocked isocyanate composition comprising a blocked isocyanate compound (A) and a stabilizer (B),
a phenol compound (a2) formed by bonding an isocyanato group of a (meth)acrylic ester compound (a1) having an isocyanato group with a hydroxyl group of a phenol compound (a2) through a urethane bond; and a compound (b1) represented by general formula (1) and an acid (b2) having a pKa of 2.0 or less.
R ¹ N=CR ² -NR ³ R ⁴ ...(1)
(In the formula, R ² is a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a group represented by -NR ⁵ _2. R ¹ , R ³ , R ⁴ , and R ⁵ are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and the two R ^5s may be the same or different. Any two or more of R ¹ , R ² , R ³ , R ⁴ , and the two R ^5s may be bonded to form a cyclic structure.)
[2] The blocked isocyanate composition according to [1], wherein the stabilizer (B) is contained in an amount of 100 to 1.00 x 10 ⁵ ppm by mass relative to the blocked isocyanate compound (A).
[3] The blocked isocyanate composition according to [1] or [2], wherein the (meth)acrylic acid ester compound (a1) having an isocyanato group is 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-(isocyanatoethyloxy)ethyl acrylate, 2-(isocyanatoethyloxy)ethyl methacrylate, or 1,1-bis(acryloyloxymethyl)ethyl isocyanate.
[4] The blocked isocyanate composition according to any one of [1] to [3], wherein the compound (b1) is a compound represented by general formula (1-2):
R ^1a N=CR ^2a -NR ^3a R ^4a ...(1-2)
(In the formula, R ^1a , R ^2a , R ^3a , and R ^4a are hydrocarbon groups, R ^1a and R ^4a are bonded to each other to form a cyclic structure, and R ^2a and R ^3a are bonded to each other to form a cyclic structure, and the sum of the carbon numbers of R ^1a and R ^4a is 3 to 20, and the sum of the carbon numbers of R ^2a and R ^3a is 3 to 20.)
[5] The blocked isocyanate composition according to any one of [1] to [3], wherein the compound (b1) represented by the general formula (1) is 1,8-diazabicyclo[5.4.0]-undecene-7, 1,5-diazabicyclo[4.3.0]-5-nonene, or 1,1,3,3-tetramethylguanidine.
[6] The blocked isocyanate composition according to any one of [1] to [5], further comprising a polymer (F) obtained by polymerizing the blocked isocyanate compound (A).
[7] The blocked isocyanate composition according to any one of [1] to [6], wherein the acid (b2) is at least one selected from the group consisting of paratoluenesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, methanesulfonic acid, 10-camphorsulfonic acid, hydrochloric acid, and sulfuric acid.
[8] A blocked isocyanate polymer obtained by polymerizing a polymerizable component contained in the blocked isocyanate composition according to any one of [1] to [7].
[9] A cured film obtained by curing the blocked isocyanate composition according to any one of [1] to [7].
[10] A method for producing a composition containing an isocyanate compound or an isocyanato group-containing (co)polymer and a stabilizer (B), comprising: holding the blocked isocyanate composition according to any one of [1] to [7] at 30°C or higher for 10 days or more, and then holding it at 80°C or higher for 0.5 hours or more to eliminate the phenol compound (a2) from the blocked isocyanate compound (A) or polymer (F).

According to the present invention, it is possible to provide a blocked isocyanate composition having excellent storage stability of the blocked isocyanate compound. It is also possible to provide a cured film obtained by satisfactorily curing a blocked isocyanate composition containing a blocked isocyanate compound having excellent storage stability, and an adhesive, a coating agent, and a molding material that utilize the formation of the cured film. Furthermore, it is possible to provide a method for producing a composition containing an isocyanate compound, etc., by releasing a blocking agent from a blocked isocyanate compound, etc., having excellent storage stability in the blocked isocyanate composition.

Hereinafter, embodiments of the present invention will be described in detail, however, the present invention is not limited to the embodiments described below.
In the present invention, (meth)acrylic acid means acrylic acid or methacrylic acid. For example, a (meth)acrylic acid ester compound means an acrylic acid ester compound or a methacrylic acid ester compound.

<Blocked isocyanate composition>
The blocked isocyanate composition according to one embodiment of the present invention contains a blocked isocyanate compound (A) and a stabilizer (B). The blocked isocyanate composition may contain a polymer (F). If necessary, the blocked isocyanate composition may contain at least one of a polymerization inhibitor (C), a monomer (D) having an ethylenically unsaturated bond, and another polymer (E). The blocked isocyanate composition according to this embodiment forms a cured film by polymerization and curing by irradiation with light or heating.

[Blocked isocyanate compound (A)]
The blocked isocyanate compound (A) used in the present invention is a compound in which the isocyanato group of a (meth)acrylic acid ester compound (a1) having an isocyanato group is bonded to a hydroxyl group of a phenol compound (a2) as a blocking agent through a urethane bond. The blocked isocyanate compound (A) is preferably a compound represented by the following general formula (2).

(R ⁶ -COO) _n R ⁷ (NH-C(=O)OPh) _m ...(2)
In formula (2), R ⁶ is CH ₂ ═CH(CH ₃ )-- or CH ₂ ═CH--.

R ⁷ is a linear or branched aliphatic hydrocarbon group having a carbon number of 1 to 7, preferably 2 to 6, more preferably 2 to 5, and even more preferably 2, with a valence of m+n, or an aromatic hydrocarbon group having a carbon number of 6 to 7 which may have a substituent such as a methyl group. R ⁷ may also contain an ether bond. From the viewpoint of ease of availability of raw materials, R ⁷ is preferably -CH ₂ -, -CH ₂ CH ₂ -, or -CH ₂ CH ₂ OCH ₂ CH ₂ -, and more preferably -CH ₂ CH ₂ -.

m and n are each independently an integer of 1 or 2, and from the viewpoint of ease of production, it is preferable that both are 1. Ph represents a phenyl group. Some or all of the hydrogen atoms of the phenyl group may be substituted with a substituent having 1 to 20 carbon atoms. Examples of the substituent include a methoxy group, an acetyl group, a propionyl group, a formyl group, a methoxycarbonyl group, an ethoxycarbonyl group, a benzyloxycarbonyl group, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and a phenyl group, and preferably a methoxy group, an acetyl group, a propionyl group, a formyl group, a methoxycarbonyl group, an ethoxycarbonyl group, and a benzyloxycarbonyl group.

Since the blocked isocyanate compound (A) has an ethylenically unsaturated hydrocarbon group, it can form a homopolymer or a copolymer with other monomers, such as a monomer (D) having an ethylenically unsaturated bond.

((Meth)acrylic acid ester compound (a1) having an isocyanato group)
The (meth)acrylic acid ester compound (a1) having an isocyanato group (—NCO) is a compound represented by the following formula (3).

(R ⁶ -COO) _n R ⁷ (NCO) _m ...(3)
In formula (3), R ⁶ , R ⁷ , m and n have the same meanings as the respective symbols in formula (2).

Examples of the (meth)acrylic acid ester compound (a1) having an isocyanato group represented by formula (3) include 2-methacryloyloxyethyl isocyanate, 3-methacryloyloxy-n-propyl isocyanate, 2-methacryloyloxyisopropyl isocyanate, 4-methacryloyloxy-n-butyl isocyanate, 2-methacryloyloxy-tert-butyl isocyanate, 2-methacryloyloxybutyl-4-isocyanate, 2-methacryloyloxybutyl-3-isocyanate, ...2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyan methacryloyloxybutyl-2-isocyanate, 2-methacryloyloxybutyl-1-isocyanate, 5-methacryloyloxy-n-pentyl isocyanate, 6-methacryloyloxy-n-hexyl isocyanate, 7-methacryloyloxy-n-heptyl isocyanate, 2-(isocyanatoethyloxy)ethyl methacrylate, 3-methacryloyloxyphenyl isocyanate, 4-methacryloyloxyphenyl isocyanate, 2-acryloyloxyethyl isocyanate, 3-acryloyloxy- n-propyl isocyanate, 2-acryloyloxyisopropyl isocyanate, 4-acryloyloxy-n-butyl isocyanate, 2-acryloyloxy-tert-butyl isocyanate, 2-acryloyloxybutyl-4-isocyanate, 2-acryloyloxybutyl-3-isocyanate, 2-acryloyloxybutyl-2-isocyanate, 2-acryloyloxybutyl-1-isocyanate, 5-acryloyloxy-n-pentyl isocyanate, 6-acryloyloxy-n-hexyl socyanate, 7-acryloyloxy-n-heptyl isocyanate, 2-(isocyanatoethyloxy)ethyl acrylate, 3-acryloyloxyphenyl isocyanate, 4-acryloyloxyphenyl isocyanate, 1,1-bis(methacryloyloxymethyl)methyl isocyanate, 1,1-bis(methacryloyloxymethyl)ethyl isocyanate, 1,1-bis(acryloyloxymethyl)methyl isocyanate, 1,1-bis(acryloyloxymethyl)ethyl isocyanate.

Of these, from the standpoint of ease of production and/or availability of raw materials, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-(isocyanatoethyloxy)ethyl acrylate, 2-(isocyanatoethyloxy)ethyl methacrylate, or 1,1-bis(acryloyloxymethyl)ethyl isocyanate is preferred, 2-acryloyloxyethyl isocyanate or 2-methacryloyloxyethyl isocyanate is more preferred, and 2-acryloyloxyethyl isocyanate is even more preferred.

(Phenol compound (a2))
The phenol compound (a2) is used as a blocking agent for the (meth)acrylic acid ester compound (a1) having an isocyanato group, and is represented by the following general formula (4).

HOPh...(4)
In formula (4), Ph represents a phenyl group. The hydrogen atom of the phenyl group may be substituted with a substituent having 1 to 20 carbon atoms. Examples of the substituent include the substituents of the phenyl group in formula (2). Examples include:

Among these, ketone compounds such as o-hydroxyacetophenone, m-hydroxyacetophenone, p-hydroxyacetophenone, o-hydroxypropiophenone, m-hydroxypropiophenone, p-hydroxypropiophenone, salicylaldehyde, 3-hydroxybenzaldehyde, and 4-hydroxybenzaldehyde, as well as methyl salicylate, methyl m-hydroxybenzoate, methyl p-hydroxybenzoate, benzyl salicylate, benzyl m-hydroxybenzoate, benzyl p-hydroxybenzoate, isoamyl salicylate, isoamyl m-hydroxybenzoate, isoamyl p-hydroxybenzoate, methyl 5-acetylsalicylate, methyl 6-acetylsalicylate, vanillin, 2-hydroxy-3 -Methoxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde, 3-hydroxy-4-methoxybenzaldehyde, 2-hydroxy-4-methoxybenzaldehyde, and other ester compounds are preferred, and ketone compounds such as o-hydroxyacetophenone, p-hydroxyacetophenone, o-hydroxypropiophenone, p-hydroxypropiophenone, salicylaldehyde, and 3-hydroxybenzaldehyde, and ester compounds such as methyl salicylate, methyl p-hydroxybenzoate, benzyl salicylate, benzyl p-hydroxybenzoate, isoamyl salicylate, isoamyl p-hydroxybenzoate, methyl 5-acetylsalicylate, and vanillin are more preferred, with methyl salicylate and p-hydroxyacetophenone being even more preferred.

The blocked isocyanate compound (A) preferably accounts for 1% by mass or more of the blocked isocyanate composition, more preferably 10% by mass or more, and even more preferably 50% by mass or more.

The blocked isocyanate compound (A) can be produced by a known method. For example, it can be produced by reacting a (meth)acrylic acid ester compound (a1) having an isocyanato group with a phenol compound (a2) in a reaction vessel as follows.

The order of adding these compounds to the reactor is not particularly limited. As a method for producing the blocked isocyanate compound (A), for example, the following methods (1) to (3) can be adopted.
(1) A method in which a phenol compound (a2) is charged into a reactor, and a (meth)acrylic acid ester compound (a1) having an isocyanato group is added under stirring to cause a reaction. (2) A method in which a (meth)acrylic acid ester compound (a1) having an isocyanato group is charged into a reactor, and a phenol compound (a2) is added under stirring to cause a reaction. (3) A method in which both a phenol compound (a2) and a (meth)acrylic acid ester compound (a1) having an isocyanato group are simultaneously added into a reactor under stirring to cause a reaction.

The reaction temperature between the (meth)acrylic acid ester compound (a1) having an isocyanato group and the phenol compound (a2) is preferably -10°C or higher and 90°C or lower, more preferably 5°C or higher and 70°C or lower, and even more preferably 10°C or higher and 40°C or lower. A reaction temperature of -10°C or higher is preferable because it is possible to improve the reaction rate and obtain the blocked isocyanate compound (A) with good productivity. A reaction temperature of 90°C or lower is also preferable because it is difficult for the reverse reaction to proceed and the compound can be obtained with high purity.

The reaction is usually carried out until the (meth)acrylic ester compound (a1) or the phenol compound (a2) having an isocyanato group disappears. The reaction time is not particularly limited, but is usually preferably 30 minutes or more and 168 hours or less. The disappearance of the phenol compound (a2) is considered to be when, for example, the result of high performance liquid chromatography analysis shows that the phenol compound (a2) is 2 parts by mass or less based on 100 parts by mass of the blocked isocyanate compound (A). On the other hand, the disappearance of the (meth)acrylic ester compound (a1) having an isocyanato group is considered to be when, for example, the result of IR measurement shows that the (meth)acrylic ester compound (a1) having an isocyanato group is 2 mass% or less based on the absorption based on the isocyanato group. The reaction time also includes the time for adding the (meth)acrylic ester compound (a1) having an isocyanato group and the phenol compound (a2) by dropwise addition, etc.

In the above production, when m = 1 in the above formula (3), it is preferable to contact the (meth)acrylic acid ester compound (a1) having an isocyanato group with the phenol compound (a2) at 0.1 to 4.0 times by mole, more preferably at 0.5 to 3.0 times by mole, even more preferably at 0.75 to 1.25 times by mole, and particularly preferably at 1.00 times by mole. The reaction ratio of these compounds is theoretically 1:1 (molar ratio), but the reaction can be smoothly carried out by contacting them at a molar ratio within the above range. In addition, when m = 2 in the above formula (3), the amount of the phenol compound (a2) to be contacted with the (meth)acrylic acid ester compound (a1) having an isocyanato group may be twice the amount in the case of m = 1.

It is also preferable to add a polymerization inhibitor (C) to the reaction system for producing the blocked isocyanate compound (A), which will be described later. The polymerization inhibitor (C) may be used after the production of the blocked isocyanate compound (A), but it is more preferable to use it during the production of the blocked isocyanate compound (A). The polymerization inhibitor reacts quickly with the radicals generated from the (meth)acryloyl groups in the blocked isocyanate compound (A) in the radical polymerization reaction, and therefore can stabilize the blocked isocyanate compound (A) so that the polymerization reaction caused by the (meth)acryloyl groups does not proceed. The polymerization inhibitor will be described in detail later.

The method of adding the polymerization inhibitor (C) is not particularly limited, but examples thereof include adding it to the reactor together with the phenol compound (a2); mixing it with the (meth)acrylic acid ester compound (a1) having an isocyanato group and adding it to the reactor; adding it to both the phenol compound (a2) and the (meth)acrylic acid ester compound (a1) having an isocyanato group and adding each of them to the reactor; and adding it to the blocked isocyanate compound (A) produced after the reaction is completed.

In the above-mentioned method for producing the blocked isocyanate compound (A), the blocked isocyanate compound (A) can be used as a solvent or dispersion medium, or the reaction can be carried out without a solvent, or a known organic solvent can be used as the solvent or dispersion medium. The solvent is not particularly limited, but examples thereof include alcohol-based solvents such as cellosolve, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, octanol, nonanol, decanol, benzyl alcohol, and hexylene glycol; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate, and propylene glycol monobutyl ether acetate; ether-based solvents such as ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, and diethylene glycol dimethyl ether; aromatic hydrocarbon-based solvents such as benzene, toluene, and xylene; and amide-based solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Halogen-substituted compounds of these solvents may also be used. Among these, ester solvents such as propylene glycol monomethyl ether acetate and ketone solvents such as acetone are preferred, and propylene glycol monomethyl ether acetate is more preferred. These may be used alone or in combination of two or more.

Other catalysts and additives may be added to the reaction system for producing the blocked isocyanate compound (A). Examples of catalysts include dibutyltin dilaurate.

[Stabilizer (B)]
The stabilizer (B) used in the present invention is a salt of a compound (b1) represented by the following general formula (1) and an acid (b2), and the pKa of the acid (b2) is 2.0 or less.

R ¹ N=CR ² -NR ³ R ⁴ ...(1)
In the formula, R ² is a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a group represented by --NR ⁵ _2. R ¹ , R ³ , R ⁴ and R ⁵ are each a hydrogen atom or R ¹ , R ² , R ³ , R ⁴ and the two R ⁵ are a hydrocarbon group having 1 to 20 carbon atoms. The two R ⁵ may be the same or different. Any two or more of the groups may be bonded to form a cyclic structure.

Compound (b1) may be a compound represented by general formula (1-2).

R ^1a N=CR ^2a -NR ^3a R ^4a ...(1-2)
In the formula, R ^1a , R ^2a , R ^{3a and R 4a are} hydrocarbon groups, R ^1a and R ^4a are bonded to each other to form a cyclic structure, and R ^2a and R ^3a are bonded to each other to form a cyclic structure. The sum of the carbon numbers of ^1a and R ^4a is 3 to 20, preferably 5 to 10, and the sum of the carbon numbers of R ^2a and R ^3a is 3 to 20, preferably 5 to 10.

Among the compounds (b1) represented by general formula (1), 1,8-diazabicyclo[5.4.0]-undecene-7, 1,5-diazabicyclo[4.3.0]-5-nonene, and 1,1,3,3-tetramethylguanidine are preferred, and 1,8-diazabicyclo[5.4.0]-undecene-7 is more preferred.

Acid (b2) is an acid having a pKa of 2.0 or less at 25°C. Of the acids having a pKa of 2.0 or less, paratoluenesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, methanesulfonic acid, 10-camphorsulfonic acid, hydrochloric acid and sulfuric acid are preferred, with paratoluenesulfonic acid being more preferred. Acids having a pKa of 2.0 or less at 25°C include those having a pKa of 2.0 or less in aqueous solution, and those that are too acidic to be measured in aqueous solution and have a pKa of 2.0 or less in aqueous solution calculated from the results of measurement in an organic solvent.

In the blocked isocyanate composition, the amount of the stabilizer (B) is preferably 100 ppm by mass or more and 1.00×10 ⁵ ppm by mass or less, more preferably 1.00×10 ³ ppm by mass or more and 1.00×10 ⁴ ppm by mass or less, relative to the blocked isocyanate compound (A). If the amount of the stabilizer (B) is 100 ppm by mass or more relative to the blocked isocyanate compound (A), the blocked isocyanate compound (A) is stable during storage, which is preferable. If the amount of the stabilizer (B) is 1.00×10 ⁵ ppm by mass or less relative to the blocked isocyanate compound (A), the blocking agent is easily removed when the blocked isocyanate compound (A) is heated, which is preferable.

[Polymerization inhibitor (C)]
The blocked isocyanate composition in one embodiment of the present invention may contain a polymerization inhibitor (C).

As the polymerization inhibitor (C), commonly used ones such as phenothiazine, p-methoxyphenol, and 2,6-di-tert-butyl-4-methylphenol (hereinafter also referred to as "BHT") can be used.

The amount of the polymerization inhibitor (C) used varies depending on the types of the phenol compound (a2) and the (meth)acrylic acid ester compound (a1) having an isocyanate group, but the total amount of the polymerization inhibitor (C) used during and after the production of the blocked isocyanate compound (A) is preferably from 10 ppm by mass to 2.00 × 10 ⁴ ppm by mass, more preferably from 50 ppm by mass to 1.00 × 10 ⁴ ppm by mass, and even more preferably from 100 ppm by mass to 1.00 × 10 ³ ppm by mass, relative to the blocked isocyanate compound (A).

[Monomer (D) having an ethylenically unsaturated bond]
The blocked isocyanate composition in one embodiment of the present invention may contain a monomer (D) having an ethylenically unsaturated bond. The monomer (D) having an ethylenically unsaturated bond does not include the blocked isocyanate compound (A) and the (meth)acrylic acid ester compound (a1) having an isocyanato group.

The monomer (D) having an ethylenically unsaturated bond is not particularly limited as long as it has an ethylenically unsaturated bond and is a compound that can be copolymerized with the blocked isocyanate compound (A).

Examples of monomers (D) having an ethylenically unsaturated bond include (meth)acrylic acid esters and derivatives thereof, styrene and derivatives thereof, vinyl acetate and derivatives thereof, (meth)acrylonitrile and derivatives thereof, vinyl esters of organic carboxylic acids and derivatives thereof, allyl esters of organic carboxylic acids and derivatives thereof, dialkyl esters of fumaric acid and derivatives thereof, dialkyl esters of itaconic acid and derivatives thereof, N-vinylamide derivatives of organic carboxylic acids, maleic acid and derivatives thereof, terminally unsaturated hydrocarbons and derivatives thereof, etc.

(Meth)acrylic acid esters and their derivatives include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, and ) Monofunctional (meth)acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxyphenylethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, and N-acryloylmorpholine; polyfunctional (meth)acrylates such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4 butanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol penta(meth)acrylate, and pentaerythritol hexa(meth)acrylate.

Examples of styrene and its derivatives include styrene, 2,4-dimethyl-α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,4,6-trimethylstyrene, o-chlorostyrene, 2-vinylbiphenyl, 1-vinylanthracene, p-isopropenyltoluene, divinylbenzene, and divinylbiphenyl.

Vinyl esters of organic carboxylic acids and their derivatives include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl adipate, etc.

Allyl esters of organic carboxylic acids and their derivatives include allyl acetate, allyl benzoate, diallyl adipate, diallyl terephthalate, diallyl isophthalate, diallyl phthalate, etc.

Examples of dialkyl esters of fumaric acid and their derivatives include dimethyl fumarate, diethyl fumarate, di-2-ethylhexyl fumarate, and dibenzyl fumarate.

Examples of dialkyl esters of maleic acid and their derivatives include dimethyl maleate, diethyl maleate, di-2-ethylhexyl maleate, and dibenzyl maleate.

Examples of dialkyl esters of itaconic acid and their derivatives include dimethyl itaconate, diethyl itaconate, 2-ethylhexyl itaconate, dibenzyl itaconate, etc.

Examples of N-vinylamide derivatives of organic carboxylic acids include N-methyl-N-vinylacetamide.

Examples of maleimide and its derivatives include N-phenylmaleimide, N-cyclohexylmaleimide, etc.

Terminally unsaturated hydrocarbons and their derivatives include 1-butene, 1-pentene, 1-hexene, vinylcyclohexane, vinyl chloride, allyl alcohol, etc.

Among these, (meth)acrylic acid esters and derivatives thereof are preferred, and methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and sec-butyl (meth)acrylate are more preferred.

The monomer (D) having an ethylenically unsaturated bond may be used alone or in combination of two or more types.

The total amount of the monomer (D) having an ethylenically unsaturated bond relative to the blocked isocyanate compound (A) is preferably 0 mol % or more and 5.0 x 10 ⁴ mol % or less, more preferably 50 mol % or more and 1 x 10 ⁴ mol % or less, and even more preferably 100 mol % or more and 2 x 10 ³ mol % or less.

[Other polymers (E)]
The blocked isocyanate composition according to one embodiment of the present invention may contain another polymer (E). The other polymer (E) is a polymer other than the polymer (F) obtained by polymerizing the blocked isocyanate compound (A). The other polymer is not particularly limited, and examples thereof include polyols, polyamines, and polythiols.

The polyol is not particularly limited, and various known polyols can be used. Specific examples include alkyl polyols such as ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, trimethylolpropane, ditrimethylolpropane, and dipentaerythritol, polyester polyols, polycarbonate diols, polybutadiene diols, trishydroxyethyl isocyanurate, bisphenol A, perfluoropolyols, and the so-called ethylene oxide-modified polyols, propylene oxide-modified polyols, and caprolactone-modified polyols in which the alkyl chains of these polyols are extended using ethylene oxide, propylene oxide, caprolactone, or the like.

There are no particular limitations on the polyamine, and various known polyamines can be used. Specific examples include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, spermidine, spermine, N,N'-bis(2-aminoethyl)-1,3-propanediamine, N,N'-bis(3-aminopropyl)-1,4-butanediamine, N,N'-bis(3-aminopropyl)ethylenediamine, agmatine, 3,3'-diaminodipropylamine, and diethylenetriamine.

There are no particular limitations on the polythiol, but various known ones can be used. Specifically, 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 4,4'-thiobisbenzenethiol, tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate, 1,3,5-benzenetrithiol, pentaerythritol tetrakis(mercaptoacetate), ethylene glycol bis(3-mercaptopropionate), 4,5-bis(mercaptomethyl)-o-xylene, 4,4'-biphenyl These include rudithiol, ethylene bis(thioglycolate), pentaerythritol tetra(3-mercaptopropionate), 1,4-butanediol bis(thioglycolate), 1,3-benzenedithiol, dithiothreitol, dithioerythritol, 1,4-benzenedithiol, bis(2-mercaptoethyl)sulfide, 1,5-dimercaptonaphthalene, 3,7-dithia-1,9-nonanedithiol, 3,6-dioxa-1,8-octanedithiol, trimethylolpropane tris(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), and trimethylolpropane tris(thioglycolate).

The amount of the other polymer (E) is preferably 10 to 10,000 parts by mass, more preferably 20 to 1,000 parts by mass, per 100 parts by mass of the total of the blocked isocyanate compound (A) and the polymer (F). In the blocked isocyanate polymer described below, the amount of the other polymer (E) is preferably 10 to 10,000 parts by mass, more preferably 20 to 1,000 parts by mass, per 100 parts by mass of the polymer derived from the blocked isocyanate compound (A).

[Polymer (F)]
The blocked isocyanate composition may contain a polymer (F) obtained by polymerizing the blocked isocyanate compound (A). The polymer (F) includes a homopolymer of the blocked isocyanate compound (A) and a copolymer obtained by copolymerizing the blocked isocyanate compound (A) with a monomer (D) having an ethylenically unsaturated bond, which will be described later. The polymerization can be carried out by a known method such as photopolymerization, radical polymerization, or thermal polymerization. In the case of radical polymerization, a radical polymerization initiator exemplified in the section [Blocked isocyanate polymer], which will be described later, can be used.

[Storage conditions]
The storage temperature of the blocked isocyanate composition is preferably from 0° C. to 50° C. For example, the temperature inside a container during container transport is usually within this temperature range, so that the blocked isocyanate compound is unlikely to be decomposed during transport, and changes in viscosity of the blocked isocyanate composition are suppressed.

[Application]
The blocked isocyanate composition can be used as a raw material for adhesives, coating agents, molding materials, etc. For example, the blocked isocyanate composition can be used for a cured film produced by polymerizing a polymerizable component in the blocked isocyanate composition to produce a blocked isocyanate polymer, and then curing the polymer.

<Blocked isocyanate polymer>
One embodiment of the present invention is a blocked isocyanate polymer obtained by polymerizing the polymerizable components in the blocked isocyanate composition described above. Polymerization also includes copolymerization. The polymerizable components in the blocked isocyanate composition include a blocked isocyanate compound (A) and a monomer (D) having an ethylenically unsaturated bond. The blocked isocyanate polymer may also include a polymer (F) present in the blocked isocyanate composition.

To radically polymerize the polymerizable components in the blocked isocyanate composition, it is preferable to use a radical polymerization initiator. The radical polymerization initiator is not particularly limited, but examples thereof include organic peroxides such as benzoyl peroxide, lauroyl peroxide, caproyl peroxide, tert-butyl peroxyoctoate, and diacetyl peroxide; azobisisobutyronitrile, azobis-α,γ-dimethylvaleronitrile, 2,2'-azobis(isobutyric acid) dimethyl, azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propanediol], and the like. 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane]disulfate dihydrate, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis(2-methylpropionamidine)dihydrochloride, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]nhydrate, 2,2'-azobis[2-methyl-N-( azo compounds such as 2,2'-azobis[N-(2-hydroxyethyl)propionamide], 2,2'-azobis(N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), and 4,4'-azobis(4-cyanovaleric acid); dialkyl peroxydicarbonates such as diisopropyl peroxycarbonate, and redox initiators.

The radical polymerization initiator is preferably used in the range of 0.01 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the blocked isocyanate compound (A) monomer in the blocked isocyanate composition.

The polymerization can be carried out by a known method, but if the reaction is carried out at a temperature higher than necessary, the blocking agent (phenol compound (a2)) of the (meth)acrylic ester compound (a1) having an isocyanato group may partially dissociate from the blocked isocyanate compound (A), and the dissociated blocking agent may act as a chain transfer agent, resulting in a broadening of the molecular weight distribution, and the resin may gel due to crosslinking derived from the isocyanato group of the (meth)acrylic ester compound (a1) having a free isocyanato group and the amino group generated by decomposition of the isocyanato group. Therefore, it is preferable to carry out the polymerization at a temperature of 120°C or less.

The weight average molecular weight of the blocked isocyanate polymer is preferably 100,000 or less, more preferably 50,000 or less, and particularly preferably 30,000 or less, in order to suppress an increase in the viscosity of the polymer. The weight average molecular weight of the blocked isocyanate polymer is preferably 1,000 or more. The weight average molecular weight can be measured by gel permeation chromatography (GPC method).

<Cured film>
One embodiment of the present invention is a cured film obtained by curing the above-mentioned blocked isocyanate composition at a predetermined temperature. When curing, it is preferable to add a base to the blocked isocyanate composition in order to improve the curing speed.

The base is not particularly limited, but examples thereof include primary, secondary, and tertiary amines such as ammonia, methylamine, ethylamine, monoethanolamine, cyclohexylamine, dimethylamine, diethylamine, methylethanolamine, diethanolamine, ethylenediamine, and triethylamine; 1,5-diazabicyclo[4.3.0]-nonene-5, 1,8-diazabicyclo[5.4.0]-undecene-7, 1,5-diazabicyclo[4.3.0]-nonene Examples of hardening accelerator compounds that become bases when heated include salts such as phenol salts of 1,8-diazabicyclo[5.4.0]-undecene-7, phenol salts of 1,8-diazabicyclo[5.4.0]-undecene-7, octylate salts of 1,8-diazabicyclo[5.4.0]-undecene-7, paratoluenesulfonate salts of 1,8-diazabicyclo[5.4.0]-undecene-7, and formates of 1,8-diazabicyclo[5.4.0]-undecene-7; and inorganic compounds such as sodium hydroxide and potassium hydroxide. Of these, 1,8-diazabicyclo[5.4.0]-undecene-7 and its phenol salts are preferred.

The reaction temperature during curing is not particularly limited, but is preferably from 60° C. to 140° C., and more preferably from 80° C. to 120° C.
The reaction time during curing is not particularly limited, but is preferably from 0.5 hours to 5 hours.

Because the blocked isocyanate composition can form a cured film in this way, it can be used favorably as an adhesive, coating agent, molding material, etc.

<Method for producing a composition containing an isocyanate compound or an isocyanato group-containing (co)polymer, etc.>
One embodiment of the present invention is a method for producing a composition containing an isocyanate compound or an isocyanato group-containing (co)polymer and a stabilizer (B), which comprises holding the above-mentioned blocked isocyanate composition at 25° C. or higher for 10 days or more (hereinafter referred to as "first-stage holding"), and then holding the composition at 80° C. or higher for 0.5 hours or more (hereinafter referred to as "second-stage holding") to eliminate the phenol compound (a2) from the blocked isocyanate compound (A) or polymer (F). The isocyanate compound is a compound in which the phenol compound (a2) has been eliminated from the blocked isocyanate compound (A). The isocyanato group-containing (co)polymer means an isocyanato group-containing polymer or an isocyanato group-containing copolymer. The isocyanato group-containing polymer is a polymer in which the phenol compound (a2) has been eliminated from a homopolymer of the blocked isocyanate compound (A). The isocyanato group-containing copolymer is a copolymer in which the phenol compound (a2) is eliminated from the copolymer of the blocked isocyanate compound (A) and the monomer (D) having an ethylenic unsaturated bond. The first-stage holding and the second-stage holding are preferably carried out under dry air (dew point 0°C). The first-stage holding is preferably carried out at 25°C or higher and 50°C or lower for 10 days or more and 45 days or less. The second-stage holding is preferably carried out at 80°C or higher and 200°C or lower for 0.5 hours or more and 20 hours or less. In terms of improving the elimination rate, it is preferable to add a base during the second-stage holding. Here, the base may be, for example, the base described in the above [cured film] section.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the examples, measurements and tests were performed using the following methods.

[viscosity]
The viscosity was measured under the following conditions using a B-type viscometer specified in JIS K 5600-2-3:2014. The sample was placed in the viscometer and the viscosity was recorded after 10 minutes.
Viscometer type: Cone plate type Cone type: CPA-52Z
Cone angle: 3°
Cone diameter: 12mm
Sample volume: 0.5 mL
Rotation speed: 50 rpm
Temperature: 23°C

[Storage stability test]
The blocked isocyanate composition was left to stand in a sealed container and exposed to dry air (dew point: 0° C.) for 2 weeks at 40° C., and the residual percentage of the blocked isocyanate compound was determined.
The residual rate (%) was calculated by (amount of the compound to be measured at the end of the storage stability test)÷(amount of the compound to be measured at the start of the storage stability test)×100.

[Deblocking test]
The blocked isocyanate composition was heated at 100° C. for 1 hour while exposed to dry air (dew point: 0° C.) in a closed container, and the conversion rate of the blocked isocyanate compound was determined.
The conversion rate (%) was calculated by {(amount of the compound to be measured at the start of the deblocking test)-(amount of the compound to be measured at the end of the deblocking test)}÷(amount of the compound to be measured at the start of the deblocking test)×100.

[Quantitative determination of compound amount]
The quantitative measurement of the blocked isocyanate compound, which is the measurement target compound in the storage stability test and the unblocking test, was carried out by HPLC under the following conditions.
Apparatus: Agilent 1200 Series
Column: Showa Denko K.K. Shodex (registered trademark) KF-801 + KF-801 + KF-801 + KF-801
Eluent: tetrahydrofuran Flow rate: 0.8 mL/min
Injection volume: 0.01mL
Column temperature: 40°C
Detector: RI (differential refractive index)
Optical system temperature: 40°C

[Production Example 1]
A 2L separable flask equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser was charged with 136.15 g of p-hydroxyacetophenone (Kanto Chemical Co., Ltd.: phenol compound (a2)), 0.07 g of BHT (Oxalis Chemicals Co., Ltd.), 300.05 g of acetone (Kanto Chemical Co., Ltd.), and 1.44 g of dibutyltin dilaurate (hereinafter also referred to as "DBTDL") (Nitto Kasei Co., Ltd.), and cooled to 15°C. 141.08 g of 2-acryloyloxyethyl isocyanate (Showa Denko K.K., AOI-VM (registered trademark): acrylic acid ester compound (a1) having an isocyanato group) was added dropwise using a dropping funnel over a period of 2 hours, and the resulting reaction liquid was aged at 25°C for 2 days. To the aged mixture, 600 mL of hexane (manufactured by Kanto Chemical Co., Inc.) was added to precipitate a compound represented by the following formula (i) (blocked isocyanate compound (A), hereinafter also referred to as "AOI-PAP"). The precipitated AOI-PAP was filtered, and the AOI-PAP was washed by adding 200 mL of hexane three times, and then dried under reduced pressure at 25°C and 1.0 kPa for 2.5 hours to obtain 181.12 g of AOI-PAP.

[Comparative Production Example 1]
579.4 g of 3,5-dimethylpyrazole (manufactured by Otsuka Chemical Co., Ltd.), 0.60 g of BHT (manufactured by Oxalis Chemicals Co., Ltd.), and 775.0 g of propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Ltd.) were added to a 5 L separable flask equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, and the mixture was cooled to 15 ° C. After cooling, 867.0 g of 2-acryloyloxyethyl isocyanate (manufactured by Showa Denko K.K., AOI-VM (registered trademark)) was added dropwise using a dropping funnel over 80 minutes. The mixture after the dropwise addition was cooled to 0 ° C., and 1600 g of hexane (manufactured by Kanto Chemical Co., Ltd.) was added and aged for one day. From the mixture after aging, a compound represented by the following formula (ii) (hereinafter also referred to as "AOI-BP") was recovered by filtration, and washing with 800 g of hexane was performed three times. The washed AOI-BP was dried under reduced pressure at 40° C. and 1.0 kPa for 5 hours to obtain 1,146.55 g of AOI-BP.

[Example 1]
A 50 mL screw tube was charged with 4.72 g of AOI-PAP produced in Production Example 1, 2.70 g of n-decanol (manufactured by Kanto Chemical Co., Ltd.), 17.30 g of o-dichlorobenzene (manufactured by Kanto Chemical Co., Ltd.), 0.0218 g of paratoluenesulfonate of 1,8-diazabicyclo[5.4.0]-undecene-7 (compound (b1) represented by general formula (1)) (manufactured by San-Apro Co., Ltd., U-CAT SA (registered trademark) 506; stabilizer (B)), and 0.0210 g of BHT (manufactured by Oxalis Chemicals Co., Ltd.: polymerization inhibitor (C)), to prepare a blocked isocyanate composition of the present invention. The amount of paratoluenesulfonate of 1,8-diazabicyclo[5.4.0]-undecene-7 relative to the amount of AOI-PAP was 4.60 × 10 ³ ppm by mass. A storage stability test was carried out using the obtained composition, and the residual rate of AOI-PAP was 98.7%. A deblocking test was carried out, and the conversion rate of AOI-PAP was 3.4%. The pKa of paratoluenesulfonic acid (acid (b2)) is -2.8.

[Comparative Example 1]
4.72 g of AOI-PAP produced in Production Example 1, 2.70 g of n-decanol (manufactured by Kanto Chemical Co., Ltd.), 17.30 g of o-dichlorobenzene (manufactured by Kanto Chemical Co., Ltd.), and 0.0224 g of BHT (manufactured by Oxalis Chemicals Co., Ltd.) were added to a 50 mL screw tube bottle to prepare the composition of Comparative Example 1. When a storage stability test was carried out using the obtained composition, the residual rate of AOI-PAP was 71.5%.

[Comparative Example 2]
A 50 mL screw tube bottle was charged with 4.72 g of AOI-PAP produced in Production Example 1, 2.70 g of n-decanol (manufactured by Kanto Chemical Co., Ltd.), 17.31 g of 2-dichlorobenzene (manufactured by Kanto Chemical Co., Ltd.), 0.0218 g of phenol salt of 1,8-diazabicyclo[5.4.0]-undecene-7 (manufactured by San-Apro Co., Ltd., U-CAT SA (registered trademark) 1), and 0.0210 g of BHT (manufactured by Oxalis Chemicals Co., Ltd.), to prepare a composition of Comparative Example 2. When a storage stability test was carried out using the obtained composition, the residual rate of AOI-PAP was 21.7%. The conversion rate of AOI-PAP was 73.1%. The pKa of phenol is 9.87.

[Comparative Example 3]
A 50 mL screw tube bottle was charged with 4.72 g of AOI-PAP produced in Production Example 1, 2.70 g of n-decanol (manufactured by Kanto Chemical Co., Ltd.), 17.31 g of o-dichlorobenzene (manufactured by Kanto Chemical Co., Ltd.), 0.0218 g of 1,8-diazabicyclo[5.4.0]-undecene-7 (manufactured by San-Apro Co., Ltd.), and 0.0210 g of BHT (manufactured by Oxalis Chemicals Co., Ltd.), to prepare a composition of Comparative Example 3. A storage stability test was carried out using the obtained composition, and the residual rate of AOI-PAP was found to be 22.6%.

[Comparative Example 4]
To a 50 mL screw tube bottle were added 4.72 g of AOI-PAP produced in Production Example 1, 2.70 g of n-decanol (manufactured by Kanto Chemical Co., Ltd.), 17.31 g of o-dichlorobenzene (manufactured by Kanto Chemical Co., Ltd.), 0.020 g of DBTDL (manufactured by Nitto Kasei Co., Ltd.), and 0.0210 g of BHT (manufactured by Oxalis Chemicals Co., Ltd.), to prepare a composition of Comparative Example 4. When a storage stability test was carried out using the obtained composition, the residual rate of AOI-PAP was 50.0%.

[Comparative Example 5]
To a 50 mL screw tube bottle were added 4.05 g of AOI-BP produced in Comparative Production Example 1, 2.69 g of n-decanol (manufactured by Kanto Chemical Co., Ltd.), 17.30 g of o-dichlorobenzene (manufactured by Kanto Chemical Co., Ltd.), 0.0205 g of U-CAT SA506 (manufactured by San-Apro Co., Ltd.), and 0.0232 g of BHT (manufactured by Oxalis Chemicals Co., Ltd.), to prepare a composition of Comparative Example 5. When a storage stability test was carried out using the obtained composition, the residual rate of AOI-BP was 94.3%.

[Comparative Example 6]
4.05 g of AOI-BP produced in Comparative Production Example 1, 2.69 g of n-decanol (manufactured by Kanto Chemical Co., Ltd.), 17.30 g of o-dichlorobenzene (manufactured by Kanto Chemical Co., Ltd.), and 0.0232 g of BHT (manufactured by Oxalis Chemicals Co., Ltd.) were added to a 50 mL screw tube bottle to prepare the composition of Comparative Example 6. When a storage stability test was carried out using the obtained composition, the residual rate of AOI-BP was 93.6%.
The results of the residual ratio of the blocked isocyanate compound in Example 1 and Comparative Examples 1 to 6 are shown in Table 1.

[Example 2]
312 g of propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Ltd.) was added to a 1 L separable flask and heated to 90° C. A mixed solution consisting of 60 g of AOI-PAP produced in Production Example 1, 111 g of methyl methacrylate (manufactured by Kanto Chemical Co., Ltd., monomer (D) having an ethylenically unsaturated bond), 129 g of butyl acrylate (manufactured by Kanto Chemical Co., Ltd., monomer (D) having an ethylenically unsaturated bond), and 12.00 g of 2,2′-azobis(isobutyrate)dimethyl (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., hereinafter also referred to as “V-601”) was added dropwise over 2 hours. The resulting reaction solution was aged for 30 minutes, and then a mixed solution consisting of 3.00 g of V-601 and 12 g of propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Ltd.) was added to the reaction solution and further aged for 3 hours. This was cooled to room temperature to obtain an AOI-PAP copolymer (polymer (F)).

32.27 g of the above AOI-PAP copolymer, 3.03 g of polyethylene glycol (PEG600, manufactured by Kanto Chemical Co., Ltd., compound (E) having active hydrogen), and 0.0276 g of U-CAT SA (registered trademark) 506 (manufactured by San-Apro Co., Ltd.) were mixed to prepare a homogeneous solution, thereby preparing the blocked isocyanate composition of the present invention. The resulting solution was kept at 40°C and allowed to stand for three weeks. The viscosity of the solution before and after standing was measured at room temperature, and was found to be 250.0 mPa·s and 256.0 mPa·s, respectively.

[Comparative Example 7]
32.28 g of the AOI-PAP copolymer synthesized in Example 2 and 3.03 g of polyethylene glycol (PEG600, manufactured by Kanto Chemical Co., Ltd.) were mixed to prepare a homogeneous solution, thereby obtaining a composition of Comparative Example 7. The resulting solution was kept at 40° C. and stored for 3 weeks. The viscosity of the solution before and after standing was measured at room temperature, and the viscosities were 246.1 mPa·s and 307.6 mPa·s, respectively.

[Comparative Example 8]
32.26 g of the AOI-PAP copolymer synthesized in Example 2, 3.02 g of polyethylene glycol (PEG600, manufactured by Kanto Chemical Co., Ltd.), and 0.0279 g of acetic acid (manufactured by Kanto Chemical Co., Ltd.) were mixed to prepare a homogeneous solution, thereby obtaining a composition of Comparative Example 8. The resulting solution was kept at 40° C. and stored for 3 weeks. The viscosity of the solution before and after standing was measured at room temperature, and the viscosities were 236.1 mPa·s and 315.5 mPa·s, respectively. The pKa of acetic acid is 4.76.
The results of the viscosity before and after standing for Example 2 and Comparative Examples 7 and 8 are shown in Table 2.

[Example 3]
In a 50 mL recovery flask, 4.72 g of AOI-PAP synthesized in Production Example 1, 2.71 g of n-decanol (Kanto Chemical Co., Ltd.), 17.30 g of o-dichlorobenzene (Kanto Chemical Co., Ltd.), 0.0236 g of U-CAT SA (registered trademark) 506 (San-Apro Co., Ltd.), 0.0237 g of U-CAT SA (registered trademark) 1 (San-Apro Co., Ltd.), and 0.0215 g of BHT (Oxalis Chemicals Co., Ltd.) were mixed to prepare a blocked isocyanate composition of the present invention. When a deblocking test was performed using the obtained composition, the conversion rate of AOI-PAP was 69.2%.

Claims (6)

A blocked isocyanate composition comprising a blocked isocyanate compound (A) and a stabilizer (B),
the blocked isocyanate compound (A) is a compound formed by urethane bonding between an isocyanato group of a (meth)acrylic ester compound (a1) having an isocyanato group and a hydroxyl group of a phenol compound (a2); the stabilizer (B) is a salt of a compound (b1) represented by general formula (1) and an acid (b2), and the pKa of the acid (b2) is 2.0 or less;
the (meth)acrylic acid ester compound (a1) having an isocyanato group is 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-(isocyanatoethyloxy)ethyl acrylate, 2-(isocyanatoethyloxy)ethyl methacrylate, or 1,1-bis(acryloyloxymethyl)ethyl isocyanate;
the phenol compound (a2) is o-hydroxyacetophenone, m-hydroxyacetophenone, or p-hydroxyacetophenone;
The compound (b1) is 1,8-diazabicyclo[5.4.0]-undecene-7 or 1,5-diazabicyclo[4.3.0]-5-nonene,
The acid (b2) is paratoluenesulfonic acid.
Blocked isocyanate composition.
R ¹ N=CR ² -NR ³ R ⁴ ...(1)
(In the formula, R ² is a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a group represented by -NR ⁵ _2. R ¹ , R ³ , R ⁴ and R ⁵ are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and the two R ^5s may be the same or different. Any two or more of R ¹ , R ² , R ³ , R ⁴ and the two R ^5s may be bonded to form a cyclic structure.) The blocked isocyanate composition according to claim 1, wherein the stabilizer (B) is contained in an amount of 100 to 1.00 x 10 ⁵ ppm by mass relative to the blocked isocyanate compound (A). The blocked isocyanate composition according to claim 1 or 2 , further comprising a polymer (F) obtained by polymerizing the blocked isocyanate compound (A). A blocked isocyanate polymer obtained by polymerizing a polymerizable component contained in the blocked isocyanate composition according to any one of claims 1 to 3 . A cured film obtained by curing the blocked isocyanate composition according to any one of claims 1 to 3 . A method for producing a composition comprising an isocyanate compound or an isocyanato group-containing (co)polymer and a stabilizer (B), comprising: holding the blocked isocyanate composition according to any one of claims 1 to 3 at 25°C or higher for 10 days or more, and then holding the composition at 80°C or higher for 0.5 hours or more to eliminate the phenol compound (a2) from the blocked isocyanate compound (A) or polymer (F).