JP6713748B2 - Blocked polyisocyanate composition - Google Patents

Description

The present invention relates to a blocked polyisocyanate composition and a method for producing the same, a thermosetting composition containing the blocked polyisocyanate, and a method for producing a cured product thereof.

It is known that an aliphatic diisocyanate or a polyisocyanate obtained from an alicyclic diisocyanate is a non-yellowing type curing agent having excellent weather resistance, chemical resistance and flexibility.
Further, the blocked polyisocyanate obtained by blocking the isocyanate group of the polyisocyanate with a blocking agent does not react at room temperature even when mixed with the active hydrogen compound as the main agent, and reacts with the active hydrogen compound by heating. proceed. Therefore, it is possible to store the mixture of the main agent and the curing agent in advance. There are oxime-based, alcohol-based, phenol-based, and amine-based blocking agents for blocking isocyanate groups, and various combinations of polyisocyanates and blocking agents have been proposed.
In recent years, from the viewpoint of environmental protection and resource saving, a low temperature curable block polyisocyanate-containing thermosetting composition has been reported for the purpose of reducing the amount of energy for heating. Specific examples include those using the active methylene-based blocked polyisocyanates of Patent Documents 1 to 4.

JP-A-8-225630 JP, 9-255915, A Special table 2001-521956 gazette JP, 2006-335954, A

However, each of the active methylene-based blocked polyisocyanates has a problem.
In the blocked polyisocyanates disclosed in Patent Documents 1 and 2, the compatibility with the main component may be insufficient depending on the type of the polyvalent active hydrogen compound as the main component. If the compatibility is not sufficient, cloudiness will occur when mixed with the main agent.
Further, in Patent Document 3, since the block polyisocyanate has high crystallinity, there is a concern that the compatibility with the main agent and the storage stability at low temperatures may be poor. Further, also in Patent Document 4, there is a concern that the low temperature curability of the thermosetting composition is insufficient.
Therefore, there is a demand for a blocked polyisocyanate that is excellent in low-temperature curability when it is made into a thermosetting composition, compatibility with the main agent, and storage stability at low temperatures.

The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, by reacting at least a part of the unreacted (unblocked) isocyanate group of the blocked polyisocyanate with the monohydric alcohol compound, The inventors have found that the problem can be solved and completed the present invention.

That is, the present invention is as follows.
[1] In a polyisocyanate obtained from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, at least a part of the isocyanate groups contained is composed of a malonic acid diester compound and an acetoacetic acid ester compound. A blocked polyisocyanate blocked with at least one blocking agent selected from the group, and
Contains a monohydric alcohol compound,
(A)/((a)+(b)+(c))=0.020 when the mole numbers of the following three bonds contained in the blocked polyisocyanate are respectively (a) to (c): Or more and less than 0.50,
Blocked polyisocyanate composition:
(A) Urethane bond between isocyanate group and monohydric alcohol compound (b) Bond between isocyanate group and malonic acid diester compound (c) Bond between isocyanate group and acetoacetic acid ester compound.
[2] The blocked polyisocyanate composition according to [1], wherein the monohydric alcohol compound is a primary alcohol having 3 to 10 carbon atoms.
[3] The blocked polyisocyanate composition according to [1] or [2], wherein the blocking agent contains both malonic acid diester and acetoacetic acid ester.
[4] The blocked polyisocyanate composition according to [1] or [2], wherein the blocking agent is diethyl malonate and/or ethyl acetoacetate.
[5] The blocked polyisocyanate composition according to any one of [1] to [4], wherein the diisocyanate is hexamethylene diisocyanate.
[6] A thermosetting composition containing the blocked polyisocyanate composition according to any one of [1] to [5] and a polyvalent active hydrogen compound.
[7] A method for producing a cured product, which comprises a step of heat-curing the thermosetting composition according to [6].

ADVANTAGE OF THE INVENTION According to this invention, the block polyisocyanate composition which makes compatible the low temperature curability at the time of setting it as a thermosetting composition, the compatibility with a main agent, and the storage stability in low temperature can be provided.

Hereinafter, a mode for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to this and various modifications are possible without departing from the gist thereof. Is possible.

(Blocked polyisocyanate composition)
The blocked polyisocyanate composition in the present embodiment is a polyisocyanate obtained from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, and at least a part of the isocyanate groups is a malonic acid diester compound and A block polyisocyanate blocked with at least one blocking agent selected from the group consisting of acetoacetic ester compounds, and a monohydric alcohol compound are included.
Then, (a) a urethane bond between an isocyanate group and a monohydric alcohol compound contained in the blocked polyisocyanate, (b) a bond between an isocyanate group and a malonic acid diester compound, and (c) an isocyanate group and an acetoacetic acid ester compound. When the number of moles of the bond between and is (a) to (c), respectively, (a)/((a)+(b)+(c)) is 0.0020 or more and less than 0.50. is there.

(Aliphatic and alicyclic diisocyanates)
In the present embodiment, the “aliphatic diisocyanate” refers to a compound having two isocyanate groups and a chain aliphatic hydrocarbon in the molecule and no aromatic hydrocarbon.
The aliphatic diisocyanate is not particularly limited, but examples thereof include butane diisocyanate, pentane diisocyanate, hexamethylene diisocyanate (hereinafter also referred to as “HDI”), trimethylhexamethylene diisocyanate, lysine diisocyanate, and the like. Use of such an aliphatic diisocyanate is more preferable because the obtained polyisocyanate precursor has a low viscosity.

In the present embodiment, the “alicyclic diisocyanate” refers to a compound having two isocyanate groups and a cycloaliphatic hydrocarbon having no aromaticity in the molecule.
The alicyclic diisocyanate is not particularly limited, but examples thereof include isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and 1,4-cyclohexane diisocyanate.

Among the above aliphatic and alicyclic diisocyanates, HDI, isophorone diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate are preferred because they are industrially easily available, and HDI is more preferred. By using HDI, the weather resistance and flexibility of the coating film obtained from the polyisocyanate composition tend to be more excellent.
The aliphatic and alicyclic diisocyanates may be used alone or in combination of two or more.

(Polyisocyanate)
Next, the polyisocyanate will be described. In the present embodiment, the “polyisocyanate” is a multimer of at least one diisocyanate selected from the group consisting of the above-mentioned aliphatic diisocyanate and alicyclic diisocyanate (multimer formed from two or more diisocyanate molecules). Is.
The polyisocyanate is not particularly limited, but for example, at least one selected from the group consisting of biuret bond, urea bond, isocyanurate bond, urethane bond, uretdione bond, allophanate bond, oxadiazinetrione bond and iminooxadiazinedione bond. Mention may be made of polyisocyanates having seed bonds.

The polyisocyanate having a biuret bond includes, for example, a so-called biuret-forming agent such as water, t-butanol or urea and a diisocyanate monomer, and a molar ratio of (biuret-forming agent)/(isocyanate group of diisocyanate monomer) is about 1/2. It can be obtained by removing unreacted diisocyanate monomer after the reaction under the condition of about 1/100 to about 1/100. These techniques are disclosed in, for example, JP-A-53-106797, JP-A-55-11452, and JP-A-59-95259.
Polyisocyanates having urea linkages can be formed from isocyanate groups and water or amine groups. It is preferable that the content of urea bonds in the polyisocyanate is low. This tends to make the obtained polyisocyanate less likely to aggregate.

The polyisocyanate having an isocyanurate bond is, for example, subjected to an isocyanurate-forming reaction of a diisocyanate monomer with a catalyst or the like, and when the conversion becomes about 5 to about 80% by mass, the reaction is stopped and unreacted diisocyanate monomer is removed. It can be obtained by removing. The isocyanurate-forming reaction catalyst used in this case is not particularly limited, but specifically, those having a basic property are preferable, for example, tetramethylammonium, tetraalkylammonium such as tetraethylammonium, hydroxide, or For example, weak organic acid salts such as acetic acid and capric acid; for example, hydroxyalkylammonium such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium and triethylhydroxyethylammonium hydroxide, or organic such as acetic acid and capric acid Weak acid salt; Alkyl carboxylic acid salts of alkylcarboxylic acids such as acetic acid, caproic acid, octylic acid, myristic acid, etc. such as tin, zinc, lead; Metal alcoholates such as sodium, potassium; Aminosilyl groups such as hexamethyldisilazane Compounds containing; Mannich bases; combined use of tertiary amines and epoxy compounds; phosphorus compounds such as tributylphosphine. The amount of these catalysts used is selected from the range of 10 ppm to 1% with respect to the mass of the raw material, diisocyanate, and alcohol polyol added as necessary. When terminating the isocyanurate-forming reaction, for example, a method of neutralizing the isocyanurate-forming reaction catalyst, for example, phosphoric acid, addition of an acidic substance such as acidic phosphoric acid ester, thermal decomposition, and a method of inactivating by chemical decomposition can be mentioned. To be

The polyisocyanate having a uretdione bond can be obtained by using a uretdione-forming reaction catalyst. The uretdione-forming reaction catalyst is not particularly limited, but specifically, trialkylphosphines such as tri-n-butylphosphine and tri-n-octylphosphine, and tris(dialkylamino) such as tris-(dimethylamino)-phosphine. ) Third phosphines such as cycloalkylphosphines such as phosphine and cyclohexyl-di-n-hexylphosphine. These compounds can also serve as an allophanatization reaction catalyst. In addition, many of these compounds also accelerate the isocyanurate-forming reaction, and produce isocyanurate group-containing polyisocyanates such as isocyanurate trimers in addition to uretdione group-containing polyisocyanates such as uretdione dimers. The uretdione dimer can also be obtained by heating without using the uretdione-forming reaction catalyst. The uretdione group-containing polyisocyanate such as the uretdione dimer of the present embodiment is preferably produced by heating in terms of storage stability.

The polyisocyanate having a urethane bond is obtained, for example, by reacting a compound having a hydroxyl group and a diisocyanate monomer at an equivalent ratio of the hydroxyl group and the isocyanate group (hydroxyl group/isocyanate group) of about 1/2 to about 1/100, It can be obtained by removing unreacted diisocyanate monomer. The reaction temperature is preferably 20 to 200° C., more preferably 40 to 150° C., and further preferably 60 to 120° C. from the viewpoint of reaction rate, suppression of side reactions, and prevention of coloration. In addition, the reaction time is preferably 10 minutes to 24 hours, more preferably 15 minutes to 15 hours, and further preferably 20 minutes to 10 hours, in the same manner as the reaction temperature. The urethanization reaction can be carried out without a catalyst or in the presence of a catalyst such as a tin-based catalyst or an amine-based catalyst.

The polyisocyanate having an allophanate bond is formed from, for example, a hydroxyl group of alcohol and an isocyanate group. To generate the allophanate group, an allophanate-forming reaction catalyst is usually used. The allophanatization reaction catalyst is not particularly limited, but specific examples thereof include alkylcarboxylic acid salts such as tin, lead, zinc, bismuth, zirconium, and zirconyl. Examples thereof include tin 2-ethylhexanoate and dibutyltin dilaurate. An organic tin compound such as lead 2-ethylhexanoate; an organic zinc compound such as zinc 2-ethylhexanoate; an organic bismuth compound such as bismuth 2-ethylhexanoate; a zirconium 2-ethylhexanoate Organic zirconium compounds; organic zirconyl compounds such as zirconyl 2-ethylhexanoate, and the like, and two or more kinds can be used in combination.
Further, the above-mentioned isocyanurate-forming reaction catalyst can also be used as an allophanate-forming reaction catalyst. When the allophanate-forming reaction is carried out using the above-mentioned isocyanurate-forming reaction catalyst, the isocyanurate group-containing polyisocyanate is naturally formed. It is economical and preferable in terms of production to carry out the allophanate-forming reaction and the isocyanurate-forming reaction using the above-mentioned isocyanurate-forming reaction catalyst as the allophanate-forming reaction catalyst.
From the viewpoint of viscosity and curability, the molar ratio of allophanate group/isocyanurate group derived from alcohol is preferably 1 to 50%, more preferably 1 to 40%, further preferably 1 to 30%. .. The allophanate group/isocyanurate group molar ratio can be measured by the method described in Examples.
The addition amount of alcohol is preferably 1/1000 to 1/10, more preferably 1/1000 to 1/100 in terms of the equivalent ratio of the hydroxyl group of alcohol and the isocyanate group of diisocyanate. When the ratio is 1/1000 or more, the average number of allophanate groups tends to increase, and the generated blocked polyisocyanate composition tends to have a low viscosity, which is preferable. Further, when it is 1/10 or less, the average number of isocyanate groups tends to increase, and the curability is excellent, which is preferable.

The polyisocyanate having an iminooxadiazinedione bond is not particularly limited, but can be obtained using, for example, a catalyst. A technique related to this is disclosed in, for example, Japanese Patent Laid-Open No. 2004-534870.
Among these bonds, polyisocyanates containing a biuret group, an isocyanurate group, a urethane group, and an allophanate group are preferable in terms of weather resistance, heat resistance, curability, and compatibility.

The isocyanate group content of polyisocyanate (hereinafter referred to as NCO group content) is the content of isocyanate groups (% by mass) with respect to the total amount of polyisocyanate (100% by mass). The NCO group content of the polyisocyanate is preferably 10 to 25% by mass, and more preferably 13 to 22% by mass in the state where the polyisocyanate contains substantially no solvent or diisocyanate.
The NCO group content of the polyisocyanate is determined, for example, by reacting the isocyanate group of the polyisocyanate with an excess of an amine (such as dibutylamine) and back titrating the remaining amine with an acid such as hydrochloric acid.

（式中、Ｒはポリイソシアネート残基、Ｒ₁およびＲ₂はアルキル基、または、アルキルオキシ基より選ばれる少なくとも１種を示す。Ｒ₁およびＲ₂は同じ構造でも異なっていてもよい） (Blocked polyisocyanate and blocking agent)
In the blocked polyisocyanate composition of the present embodiment, some of the isocyanate groups (located at the terminals) contained in the polyisocyanate are blocked (blocked) with a blocking agent.
As the blocking agent, at least one active methylene compound selected from the group consisting of malonic acid diester compounds and acetoacetic acid ester compounds is used.
When the isocyanate group is blocked with these active methylene compounds, the blocked isocyanate group has an amide structure represented by the following general formula (1).

(In the formula, R represents a polyisocyanate residue, R ₁ and R ₂ represent at least one selected from an alkyl group or an alkyloxy group. R ₁ and R ₂ may have the same structure or different)

Specific examples of the malonic acid diester compound used as the blocking agent include dimethyl malonate, diethyl malonate, di-n-propyl malonate, diisopropyl malonate, di-n-butyl malonate, diisobutyl malonate and di-t-malonate. Examples include butyl, t-butylmethyl malonate, di-n-hexyl malonate, di2-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 ester, malonic acid Di-n-hexyl and di-2-ethylhexyl malonate are preferable, and more preferably dimethyl malonate, diethyl malonate, di-n-propyl malonate, diisopropyl malonate, di-n-butyl malonate, diisobutyl malonate, malonic acid. Di-t-butyl and t-butylmethyl malonate are more preferred, dimethyl malonate and diethyl malonate are more preferred, and diethyl malonate is still more preferred. These malonic acid diester compounds may be used alone or in combination of two or more.
From the viewpoint of low-temperature curability, preferably 50 equivalent% or more, more preferably 60 equivalent% or more, still more preferably 80 equivalent% or more of the isocyanate groups contained in the polyisocyanate are blocked with the malonic acid diester.

Examples of the acetoacetate compound include methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, n-propyl acetoacetate, t-butyl acetoacetate, n-butyl acetoacetate, and phenyl acetoacetate. Among them, ethyl acetoacetate is preferable. These acetoacetic acid ester compounds may be used alone or in combination of two or more.
From the viewpoint of low-temperature curability and suppression of yellowing, the isocyanate group blocked with acetoacetic acid ester is preferably 50 equivalent% or less of the isocyanate group contained in the polyisocyanate, more preferably 40 equivalent% or less, It is preferably 30 equivalent% or less.

As the blocking agent, in addition to malonic acid diester and acetoacetic acid ester, other blocking agents can be used together. In this case, the total ratio of the malonic acid diester and the acetoacetic acid ester in the blocking agent is preferably 50 mol% or more, and more preferably 70 mol% or more.
As other blocking agents, for example, alcohol-based, alkylphenol-based, phenol-based, active methylene-based other than malonic acid diester, mercaptan-based, acid amide-based, acid imide-based, imidazole-based, urea-based, oxime-based, amine-based, Examples thereof include imide compounds and pyrazole compounds.

The effective isocyanate group content rate of the blocked polyisocyanate (hereinafter referred to as the effective NCO group content rate) is the content rate of the isocyanate groups potentially existing in the total mass of the blocked polyisocyanate.
The effective NCO group content of the blocked polyisocyanate is preferably 3 to 22% by mass, and more preferably 5 to 18% by mass, in a state that substantially no solvent is contained.
The effective NCO group content is determined from the charged amount of polyisocyanate and the NCO group content, and the charged amount of the blocking agent.

(Monohydric alcohol compound)
In this embodiment, the monohydric alcohol compound contained in the blocked polyisocyanate composition is not limited. The monohydric alcohol compound can react with an unreacted (unblocked) isocyanate group of the blocked polyisocyanate, or can undergo a transesterification reaction with an ester group at the terminal of the blocked polyisocyanate.
In the block polyisocyanate composition of the present embodiment, by including this monohydric alcohol compound, crystallization of the block polyisocyanate composition can be significantly suppressed.

The carbon number of the monohydric alcohol compound depends on the storage stability and compatibility when the block polyisocyanate composition is mixed with the polyvalent active hydrogen compound to form a thermosetting composition, and the crystallinity of the block polyisocyanate composition. From the viewpoint of suppression, it is preferably 3 or more and 10 or less, more preferably 4 or more and 9 or less, still more preferably 4 or more and 8 or less. In addition, the boiling point is preferably 200° C. or lower, more preferably 80 to 180° C., and even more preferably 90 to 160° C., from the viewpoint of ease of solvent scattering and low temperature curability.
Examples of the monohydric alcohol compound having such carbon number and boiling point include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, 2-butanol, t-butanol, n-pentanol. , Iso-pentanol, 2-methyl-1-butanol, n-hexanol, 2-methyl-1-pentanol, 2-ethyl-1-butanol, n-heptanol, n-octanol, 2-ethyl-1-hexanol , Methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carbitol, propylene glycol monomethyl ether, cyclohexanol, phenol, benzyl alcohol and the like, and one kind or two or more kinds can be selected and used.
Further, the carbon number of the monohydric alcohol compound is higher than the carbon number of the terminal alkyl group bonded to the malonic acid diester and the acetoacetic acid ester in terms of the compatibility between the block polyisocyanate composition and the polyvalent active hydrogen compound. Is preferred.

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

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

In the block polyisocyanate composition of the present embodiment, it is essential that at least a part of the unreacted isocyanate groups contained in the block polyisocyanate form a urethane bond with the monohydric alcohol compound. The amount of the urethane bond structure formed by the alcohol compound and the isocyanate group is the number of moles of the urethane bond structure (a), the number of moles of the bond structure between the isocyanate group and the malonic acid diester compound (b), the isocyanate group The molar ratio of (a)/((a)+(b)+(c)) when the number of moles of the bond structure between the acetoacetic acid ester compound and (c) is (c) is 0. It is 0020 or more and less than 0.50.
According to the research conducted by the present inventors, in the case where the blocked polyisocyanate contains a part of unreacted unreacted isocyanate groups, and it reacts with the monohydric alcohol compound and has a urethane bond, It was found that crystallization was extremely unlikely to occur and the compatibility was excellent. However, the above ratio is preferably 0.01 or more and 0.40 or less, and more preferably 0.02 or more and 0.30 or less.

(Method for producing blocked polyisocyanate composition)
In the present embodiment, the blocked polyisocyanate can be obtained by reacting the above polyisocyanate with the above blocking agent.
A blocked reaction catalyst is usually used in the above reaction. The blocking reaction catalyst is preferably a basic compound, for example, a metal alcoholate such as sodium methylate, sodium ethylate, sodium phenolate, potassium methylate; tetraalkylammonium such as tetramethylammonium, tetraethylammonium, tetrabutylammonium. Hydroxide and its weak organic acid salts such as acetates, octylates, myristates, benzoates; Alkali metal salts of alkylcarboxylic acids such as acetic acid, caproic acid, octylic acid, myristic acid; acetic acid, caproic acid , Metal salts of tin, zinc, lead and the like of alkylcarboxylic acids such as octylic acid and myristic acid; aminosilyl group-containing compounds such as hexamethylenedisilazane; hydroxides of alkali metals such as lithium, sodium and potassium. ..

The amount of the catalyst added is not limited, but is generally 0.01 to 5% by mass, preferably 0.05 to 3% by mass, and particularly preferably 0.1 to 2% by mass, based on the polyisocyanate. When the amount of the catalyst added is reduced, the residual amount of the isocyanate group that is not blocked during the blocking reaction tends to increase. The reaction between the polyisocyanate and the active methylene compound can be carried out regardless of the presence or absence of a solvent.
The reaction between the polyisocyanate and the blocking agent can be generally carried out at −20 to 150° C., but it is preferably 0 to 100° C. from the viewpoint of suppressing side reactions and reaction efficiency. When the reaction temperature is lowered, the residual amount of the isocyanate groups that are not blocked during the blocking reaction tends to increase.
The reaction time between the polyisocyanate and the blocking agent can be generally 0.1 to 6 hours, but is preferably 0.5 to 4 hours from the viewpoint of optimizing the amount of urethane bond structure to be produced. .. When the reaction time is shortened, the residual amount of the isocyanate groups that are not blocked during the blocking reaction tends to increase.

By heating the block polyisocyanate obtained as described above in the presence of a monohydric alcohol compound, the unreacted isocyanate group of the block polyisocyanate reacts with the active hydrogen in the monohydric alcohol compound, and storage A blocked polyisocyanate composition with enhanced stability is obtained.
The heating temperature and heating time at this time may be, for example, 50 to 180° C. and 10 to 480 minutes.

In the present embodiment, in the blocked polyisocyanate composition, during the reaction of blocking the polyisocyanate with a blocking agent so as to form a urethane bond between the unreacted isocyanate group and the monohydric alcohol compound, Leave the isocyanate groups in the reaction.
As a method of leaving unblocked isocyanate groups, for example, the amount of the blocking agent added in advance, less than the molar amount of the isocyanate group of the polyisocyanate, a method of controlling the addition amount of the blocking reaction catalyst, the reaction temperature or reaction time The method of controlling is mentioned. These methods may be used alone or in combination.
Alternatively, a method of simultaneously forming the blocking agent and the monohydric alcohol compound to form a urethane bond between the isocyanate group of the blocked polyisocyanate and the monohydric alcohol compound can be used.
By the method as described above, a blocked polyisocyanate composition in which an unreacted isocyanate group in the blocked polyisocyanate and a monohydric alcohol compound form a urethane bond can be produced.
The block polyisocyanate composition produced in the above steps can achieve both low-temperature curability, compatibility with the base resin, and storage stability at low temperatures.

(Other additives)
Various organic solvents can be added to the blocked polyisocyanate composition of the present embodiment depending on the purpose and application.
The organic solvent to be added is not particularly limited, for example, hexane, heptane, octane and other aliphatic hydrocarbon solvents; cyclohexane, methylcyclohexane and other alicyclic hydrocarbon solvents; acetone, methyl ethyl ketone, methyl isobutyl ketone, Ketone-based solvents such as cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, methyl lactate, ethyl lactate; aromas such as toluene, xylene, diethylbenzene, mesitylene, anisole, benzyl alcohol, phenylglycol and chlorobenzene. Group solvent; glycol solvent such as ethylene glycol monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether; ether solvent such as diethyl ether, tetrahydrofuran, dioxane; dichloromethane , 1,2-dichloroethane, chloroform and other halogenated hydrocarbon solvents; N-methyl-2-pyrrolidone and other pyrrolidone solvents; N,N-dimethylacetamide, N,N-dimethylformamide and other amide solvents; dimethyl Examples thereof include sulfoxide solvents such as sulfoxide; lactone solvents such as γ-butyrolactone; amine solvents such as morpholine; and mixtures thereof.

Further, the block polyisocyanate composition of the present embodiment may be added with another block polyisocyanate composed of a multimer of diisocyanates other than the aliphatic and alicyclic diisocyanates at an arbitrary ratio. At that time, the blocking agent bonded may be the same as or different from the above-mentioned blocked polyisocyanate.

Further, the blocked polyisocyanate composition of the present embodiment, depending on the purpose and use, a curing accelerating catalyst and an antioxidant, an ultraviolet absorber, a light stabilizer, a pigment, a leveling agent, a plasticizer, a rheology control agent, a surface active agent. Various additives such as agents can be contained.
The curing accelerator is not particularly limited, but examples thereof include tin compounds such as dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, dimethyltin dineodecanoate, and bis(2-ethylhexanoic acid)tin; 2- Zinc compounds such as zinc ethylhexanoate and zinc naphthenate; titanium compounds such as titanium 2-ethylhexanoate and titanium diisopropoxybis(ethylacetonate); cobalt compounds such as cobalt 2-ethylhexanoate and cobalt naphthenate; Examples thereof include bismuth compounds such as bismuth 2-ethylhexanoate and bismuth naphthenate; zirconium compounds such as zirconium tetraacetylacetonate, zirconyl 2-ethylhexanoate and zirconyl naphthenate; amine compounds.
The antioxidant is not particularly limited, and examples thereof include hindered phenol compounds, phosphorus compounds, sulfur compounds and the like.
The ultraviolet absorber is not particularly limited, and examples thereof include a benzotriazole-based compound, a triazine-based compound, and a benzophenone-based compound.
The light stabilizer is not particularly limited, and examples thereof include hindered amine compounds, benzotriazole compounds, triazine compounds, benzophenone compounds, and benzoate compounds.
The pigment is not particularly limited, but examples thereof include titanium oxide, carbon black, indigo, quinacridone, pearl mica, and aluminum.
The leveling agent is not particularly limited, and examples thereof include silicone oil.
The plasticizer is not particularly limited, but examples thereof include phthalates, phosphoric acid compounds, polyester compounds, and the like.
The rheology control agent is not particularly limited, but examples thereof include hydroxyethyl cellulose, urea compounds, and microgels.
The surfactant is not particularly limited, and examples thereof include known anionic surfactants, cationic surfactants and amphoteric surfactants.
In addition, in the polyisocyanate composition and the blocked polyisocyanate composition according to the present embodiment, the content of the above-mentioned other additives is preferably 0 to 80% by mass, and 0 to 70% by mass. It is more preferably 0 to 60% by mass.

(Thermosetting composition, cured product)
The thermosetting composition of the present embodiment contains the blocked polyisocyanate composition and a polyvalent active hydrogen compound. A cured product can be obtained by heating and curing the thermosetting composition.
The thermosetting composition of the present embodiment can be produced by mixing the blocked polyisocyanate composition with a polyvalent active hydrogen compound.
By heating the thermosetting composition of the present embodiment, the block polyisocyanate and the active hydrogen in the polyvalent active hydrogen compound undergo a transesterification reaction to give a cured product.

Hereinafter, the polyvalent active hydrogen compound and the like that can be used in the thermosetting composition according to the present embodiment will be described.
The polyvalent active hydrogen compound is a compound in which two or more active hydrogens are bonded in the molecule. Examples of the polyvalent active hydrogen compound include, but are not particularly limited to, polyols, polyamines, alkanolamines, polythiols, and the like, but polyols are mostly used.

The polyamine is not particularly limited, but examples thereof include diamines such as ethylenediamine, propylenediamine, butylenediamine, triethylenediamine, hexamethylenediamine, 4,4′-diaminodicyclohexylmethane, piperazine, 2-methylpiperazine and isophoronediamine. Chain polyamines having three or more amino groups such as bishexamethylenetriamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentamethylenehexamine, and tetrapropylenepentamine; 1,4,7,10,13,16 -Cyclic polyamines such as hexaazacyclooctadecane, 1,4,7,10-tetraazacyclodecane, 1,4,8,12-tetraazacyclopentadecane and 1,4,8,11-tetraazacyclotetradecane Can be mentioned.
The alkanolamine is not particularly limited, but examples thereof include monoethanolamine, diethanolamine, triethanolamine, aminoethylethanolamine, N-(2-hydroxypropyl)ethylenediamine, mono-, di-(n- or iso-). ) Propanol amine, ethylene glycol-bis-propyl amine, neopentanol amine, methyl ethanol amine and the like.
The polythiol is not particularly limited, and examples thereof include bis-(2-hydrothioethyloxy)methane, dithioethylene glycol, dithioerythritol, and dithiothreitol.

The polyol is not particularly limited, but examples thereof include polyester polyol, acrylic polyol, polyether polyol, polyolefin polyol, fluorine polyol, polycarbonate polyol, polyurethane polyol, and epoxy resin.
The polyester polyol is not particularly limited, but examples thereof include polyester polyols and polycaprolactone polyols. The polyester polyol is not particularly limited, and examples thereof include those obtained by a condensation reaction of a dibasic acid alone or a mixture with a polyhydric alcohol alone or a mixture. The dibasic acid is not particularly limited, but for example, a dibasic acid selected from the group consisting of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid. An acid is mentioned. The polyhydric alcohol is not particularly limited, and specific examples thereof include polyhydric alcohols selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, glycerin and the like. The polycaprolactone polyols are not particularly limited, but can be obtained, for example, by ring-opening polymerization of ε-caprolactone using a polyhydric alcohol.
The acrylic polyol is not particularly limited, but for example, a single or mixture of an ethylenically unsaturated bond-containing monomer having a hydroxyl group, and another ethylenically unsaturated bond-containing monomer copolymerizable therewith Examples thereof include those which are copolymerized alone or with a mixture.
The polyether polyol is not particularly limited, but for example, a hydroxide such as lithium, sodium, potassium or the like, or a strongly basic catalyst such as an alcoholate or an alkylamine is used, and a polyvalent hydroxy compound is used alone or as a mixture. Polyether polyols obtained by adding alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide, alone or in a mixture; to polyfunctional compounds such as ethylenediamine, etc., by reacting alkylene oxides Polyether polyols that can be used; so-called polymer polyols that can be obtained by polymerizing acrylamide and the like using the above polyethers as a medium.
The polyolefin polyol is not particularly limited, but examples thereof include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.
The above-mentioned fluorine polyol is not particularly limited, but is, for example, a polyol containing fluorine in the molecule, such as fluoroolefins and cycloolefins disclosed in JP-A-57-34107 and JP-A-61-275311. Examples thereof include copolymers such as vinyl ether, hydroxyalkyl vinyl ether, and monocarboxylic acid vinyl ester.
The polycarbonate polyol is not particularly limited, for example, dialkyl carbonates such as dimethyl carbonate, alkylene carbonates such as ethylene carbonate, low molecular weight carbonate compounds such as diaryl carbonates such as diphenyl carbonate, and the low-carbon carbonates mentioned in the above polyester polyol. Examples thereof include those obtained by polycondensation of a molecular polyhydric alcohol.
The polyurethane polyol is not particularly limited, and examples thereof include those obtained by a conventional method, for example, by reacting a polyol with a polyisocyanate.

Among the polyols listed above, acrylic polyols and polyester polyols are preferable.
The hydroxyl value of the above-mentioned polyol is preferably 10 to 300 mgKOH/g per cured product in terms of crosslink density and mechanical properties of the cured product. When the hydroxyl value per resin is 10 mgKOH/g or more, it is possible to prevent the crosslink density from decreasing and sufficiently achieve the target physical properties of the present embodiment. On the other hand, when the hydroxyl value per resin is 300 mgKOH/g or less, it is possible to prevent the crosslinking density from increasing excessively and to maintain the mechanical properties of the coating film at a high level. The hydroxyl value can be determined by a titration method.

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

The thermosetting composition of this embodiment may further contain other curing agents such as a melamine curing agent and an epoxy curing agent.
The melamine-based curing agent is not particularly limited, but examples thereof include a completely alkyl etherified melamine resin, a methylol group-type melamine resin, and an imino group-type melamine resin partially having an imino group.
When a melamine-based curing agent is used in combination, it is effective to add an acidic compound. Specific examples of the acidic compound are not particularly limited, and examples thereof include carboxylic acid, sulfonic acid, acidic phosphoric acid ester, and phosphorous acid ester.
The carboxylic acid is not particularly limited, and examples thereof include acetic acid, lactic acid, succinic acid, oxalic acid, maleic acid, and decanedicarboxylic acid.
The sulfonic acid is not particularly limited, but examples thereof include paratoluene sulfonic acid, dodecylbenzene sulfonic acid, and dinonylnaphthalene disulfonic acid.
The acidic phosphate ester is not particularly limited, and examples thereof include dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, dilauryl phosphate, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate and the like.
The phosphite is not particularly limited, for example, diethyl phosphite, dibutyl phosphite, dioctyl phosphite, dilauryl phosphite, monoethyl phosphite, monobutyl phosphite, monooctyl phosphite, monolauryl phosphite Etc.

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

(Use)
The block polyisocyanate composition of the present embodiment is, for example, a curable composition such as a coating composition, a pressure-sensitive adhesive composition, an adhesive composition, and a casting composition; various surface-treating agent compositions such as fiber treating agents. Can be used as various elastomer compositions; crosslinking agents such as foam compositions; modifiers; additives.
The coating composition containing the blocked polyisocyanate composition of the present embodiment is suitably used as a primer or an intermediate coating and a top coating on various materials by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, etc. It In addition, this coating composition is used to impart cosmetic properties, weather resistance, acid resistance, rust resistance, chipping resistance, adhesion, etc. to pre-coated metal containing rust-proof steel plates, automobile coating, plastic coating, etc. It is preferably used.
Examples of the field of use of the pressure-sensitive adhesive composition or adhesive composition containing the blocked polyisocyanate composition of the present embodiment include automobiles, building materials, home appliances, woodworking, and laminates for solar cells. Among them, optical members for liquid crystal displays of home electric appliances such as televisions, personal computers, digital cameras, and mobile phones exhibit various functions, and therefore films and plates of various adherends need to be laminated. Since the material used between the film and the plate of various adherends is required to have sufficient tackiness or adhesiveness, use of the tackiness agent composition or the glue composition containing the blocked polyisocyanate composition of the present embodiment Preferred as an example.
The adherend on which the curable composition containing the blocked polyisocyanate composition of the present embodiment can be used is not particularly limited, and examples thereof include glass; various metals such as aluminum, iron, zinc steel plate, copper, and stainless steel. ; Porous materials such as wood, paper, mortar, stone materials; Fluorine-coated, urethane-coated, acrylic urethane-coated materials; Silicone-based cured products, modified silicone-based cured products, urethane-based cured products, etc. Materials: Rubbers such as vinyl chloride, natural rubber, synthetic rubber; leathers such as natural leather and artificial leather; fibers such as plant fiber, animal fiber, carbon fiber, glass fiber; non-woven fabric, polyester, acrylic, polycarbonate Films and plates of resins such as triacetyl cellulose and polyolefin; UV curable acrylic resin layers, inks such as printing inks and UV inks.

The present invention will be described in more detail with reference to Examples and Comparative Examples.
In the following, “parts” and “%” indicating the amount or ratio of a product mean values on a mass basis unless otherwise specified.

[Measurement and calculation method]
The methods for measuring and calculating various parameters in Examples and Comparative Examples are shown below.

(Isocyanate group (hereinafter, NCO group) content of polyisocyanate (% by mass))
After the isocyanate group of polyisocyanate was neutralized with an excess of 2N amine, it was determined by back titration with 1N hydrochloric acid.

(Viscosity of polyisocyanate)
It was measured with an E-type viscometer (manufactured by Tokimec Co., Ltd.), and a standard rotor (1°34′×R24) was used as the rotor. The number of rotations is as follows.
100r. p. m. (When less than 128 mPa·s)
50r. p. m. (When 128 mPa·s or more and less than 256 mPa·s)
20r. p. m. (When 256 mPa·s or more and less than 640 mPa·s)
10r. p. m. (When 640 mPa·s or more and less than 1,280 mPa·s)
5r. p. m. (When 1,280 mPa·s or more and less than 2,560 mPa·s)

(Effective NCO group content of blocked polyisocyanate composition)
It was calculated from the following formula.
Effective NCO group content (value in actual state (state including solvent), mass%)
= NCO group content of polyisocyanate (% by mass)
X (amount of polyisocyanate charged (g)/(amount of polyisocyanate charged (g)+amount of blocking agent (g)))
×Solid content ratio (ratio of solid content (components other than solvent) in the composition) (mass %)/100

(Molar ratio of urethane bond between isocyanate group and monohydric alcohol compound)
1H-NMR of the blocked polyisocyanate compositions obtained in Synthesis Examples 2 to 7 was measured, and an amino group (around 4.8 ppm) resulting from a urethane bond obtained by the monohydric alcohol compound and the isocyanate group being bonded. , An amino group adjacent to an amide body formed by binding of an isocyanate group and diethyl malonate (around 7.3 ppm: keto body, around 8.0 ppm: diamide diester body, around 9.8 ppm: enol body), And from the area of the peak due to the amino group (around 7.2 ppm: keto body, near 9.2 ppm: enol body) adjacent to the amide body formed by the bonding of the isocyanate group and ethyl acetoacetate, The molar ratio of the urethane bond was determined by the formula.
Molar ratio of the urethane bond=(a)/((a)+(b)+(c))
(B): Number of amino groups adjacent to an amide body formed by binding of an isocyanate group and diethyl malonate (=peak area near 7.3 ppm+peak area near 8.0 ppm/2/peak area near +9.8 ppm) The peak around 8.0 ppm (diamide diester form) is a structure having two amino groups in one bond structure, so 1/2 of the peak area was taken as the number of bond structures) to determine the isocyanate group and malon. Number of bond structures with the acid diester compound (number of moles).
(C): Isocyanate group determined from the number of amino groups adjacent to the amide compound formed by the bonding of an isocyanate group and ethyl acetoacetate (=peak area near 7.2 ppm+peak area near 9.2 ppm) Number of bond structures with the acetoacetic ester compound (number of moles).
(A): Isocyanate group and monovalent determined from the number of amino groups (=peak area near 4.8 ppm) resulting from urethane bond obtained by bonding of isocyanate group and n-butanol, isobutanol or isopropanol Number of urethane bond structures (moles) with alcohol compounds.

[Synthesis method]
The blocked polyisocyanate compositions in Examples and Comparative Examples and the synthesis method of the polyisocyanate used for their synthesis are shown below.
(Synthesis example 1)
(Synthesis of polyisocyanate)
A 4-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube, and a dropping funnel was placed in a nitrogen atmosphere and charged with 1000 g of hexamethylene diisocyanate (HDI), and the temperature inside the reactor was maintained at 60° C. under stirring. did. Then, 2.1 g of tetramethylammonium acetate (5.0% by mass solution of 2-butanol) as an isocyanurate-forming reaction catalyst was added and reacted. After 4 hours, the reaction end point was confirmed by measuring the refractive index of the reaction solution, and 0.2 g of phosphoric acid (85 mass% aqueous solution) was added to stop the reaction.
After filtering the reaction solution, unreacted HDI was removed using a thin film distillation apparatus to obtain a polyisocyanate having an isocyanurate group. The obtained polyisocyanate had a viscosity at 25° C. of 2500 mPa·s and an NCO group content of 22.2% by mass.

(Synthesis example 2)
(Production of Block Polyisocyanate Composition A)
A 4-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube was placed in a nitrogen atmosphere, 100 parts of the polyisocyanate obtained in Synthesis Example 1 and 42.3 parts of butyl acetate were charged, and diethyl malonate was added. A mixture of 71.1 parts, ethyl acetoacetate 14.5 parts and 28% sodium methylate methanol solution 0.8 parts was added at room temperature, and the reaction was continued at 80° C. for 1 hour. Then, 76.0 parts of 1-butanol was added, and the mixture was stirred at 80° C. for 2 hours.
Table 1 shows the effective NCO group content and the molar ratio of the block polyisocyanate 60% by mass of the block polyisocyanate composition A.

(Synthesis example 3)
(Production of Blocked Polyisocyanate Composition B)
In a device similar to that for the blocked polyisocyanate composition A, 100 parts of polyisocyanate and 42.3 parts of butyl acetate were charged, diethyl malonate 64.1 parts, ethyl acetoacetate 13.1 parts, 28% sodium methylate methanol. A mixture of 0.8 parts of the solution was added at room temperature, and the reaction was continued at 80° C. for 1 hour. Thereafter, 84.0 parts of 1-butanol was added, and the mixture was stirred at 80° C. for 2 hours while flowing nitrogen.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition B in which the blocked polyisocyanate is 60% by mass.

(Synthesis example 4)
(Production of Blocked Polyisocyanate Composition C)
In a device similar to that for the blocked polyisocyanate composition A, 100 parts of polyisocyanate and 42.3 parts of butyl acetate were charged, 56.9 parts of diethyl malonate, 11.6 parts of ethyl acetoacetate, and 28% sodium methylate methanol. A mixture of 0.8 parts of the solution was added at room temperature, and the reaction was continued at 80° C. for 1 hour. Thereafter, 93.0 parts of 1-butanol was added, and the mixture was stirred at 80°C for 2 hours.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition C in which the blocked polyisocyanate is 60% by mass.

(Synthesis example 5)
(Production of Blocked Polyisocyanate Composition D)
In a device similar to that for the blocked polyisocyanate composition A, 100 parts of polyisocyanate and 42.3 parts of butyl acetate were charged, 56.9 parts of diethyl malonate, 11.6 parts of ethyl acetoacetate, and 28% sodium methylate methanol. A mixture of 0.4 parts of the solution was added at room temperature, and the reaction was continued at 80° C. for 0.5 hours. Thereafter, 93.0 parts of 1-butanol was added, and the mixture was stirred at 80°C for 2 hours.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition D in which the blocked polyisocyanate is 60% by mass.

(Synthesis example 6)
(Production of Blocked Polyisocyanate Composition E)
In a device similar to that for the block polyisocyanate composition A, 100 parts of polyisocyanate and 42.3 parts of butyl acetate were charged, 71.1 parts of diethyl malonate, 14.5 parts of ethyl acetoacetate, 28% sodium methylate methanol. A mixture of 0.8 parts of the solution was added at room temperature, and the reaction was continued at 80° C. for 0.5 hours. Thereafter, 76.0 parts of 1-butanol was added, and the mixture was stirred at 80° C. for 2 hours while flowing nitrogen.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition E in which the blocked polyisocyanate is 60% by mass.

(Synthesis example 7)
(Production of Blocked Polyisocyanate Composition F)
A blocked polyisocyanate composition F was synthesized in the same manner as in Synthesis Example 2 except that the 28% sodium methylate methanol solution was changed to 1.5 parts.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition F in which the blocked polyisocyanate is 60% by mass.

(Synthesis example 8)
(Production of Blocked Polyisocyanate Composition G)
A blocked polyisocyanate composition G was synthesized in the same manner as in Synthesis Example 2 except that the reaction temperature and the reaction time were 60° C. and 3 hours.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition G in which the blocked polyisocyanate is 60% by mass.

(Synthesis example 9)
(Production of Block Polyisocyanate Composition H)
A blocked polyisocyanate composition H was synthesized in the same manner as in Synthesis Example 2 except that 1-butanol was changed to isobutanol.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition H in which the blocked polyisocyanate is 60% by mass.

(Synthesis example 10)
(Production of Block Polyisocyanate Composition I)
A blocked polyisocyanate composition I was synthesized in the same manner as in Synthesis Example 2, except that 76.0 parts of 1-butanol was changed to 61.0 parts of isopropanol.
Table 1 shows the effective NCO group content and the molar ratio of the block polyisocyanate composition I containing 60% by mass of the block polyisocyanate.

(Synthesis example 11)
(Production of Block Polyisocyanate Composition J)
A blocked polyisocyanate composition J was synthesized in the same manner as in Synthesis Example 2 except that 4.0 parts of 28% sodium methylate methanol solution was added.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition J in which the blocked polyisocyanate is 60% by mass.

(Synthesis example 12)
(Production of Block Polyisocyanate Composition K)
In a device similar to that for the blocked polyisocyanate composition A, 100 parts of polyisocyanate and 42.3 parts of butyl acetate were charged, and 28.4 parts of diethyl malonate, 5.8 parts of ethyl acetoacetate, 28% sodium methylate methanol. A mixture of 0.8 parts of the solution was added at room temperature, and the reaction was continued at 80° C. for 0.5 hours. Then, 127.4 parts of 1-butanol was added and stirred at 80° C. for 2 hours.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition K in which the blocked polyisocyanate is 60% by mass.

(Synthesis example 13)
(Production of Block Polyisocyanate Composition L)
A blocked polyisocyanate composition L was synthesized by the same method as in Synthesis Example 2 except that the reaction temperature and the reaction time were 80° C. and 0.2 hours.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition L in which the blocked polyisocyanate is 60% by mass.

(Synthesis Example 14)
(Production of Block Polyisocyanate Composition M)
A blocked polyisocyanate composition M was synthesized in the same manner as in Synthesis Example 2, except that the reaction temperature and the reaction time were changed to 80° C. and 6 hours.
Table 1 shows the effective NCO group content and the molar ratio of the blocked polyisocyanate composition M in which the blocked polyisocyanate is 60% by mass.

[Evaluation method]
The evaluation methods of various physical properties of the blocked polyisocyanate compositions in Examples and Comparative Examples are shown below.
(Curable)
A polyisocyanate composition and an acrylic polyol (Setalux1152, manufactured by Nuplex Resins, hydroxyl value 70.4 mgKOH/g (appearance), solid content 61 mass%) are blended so that NCO/OH=1.0, A coating composition was prepared by diluting to 50% solids with butyl acetate.
The obtained coating composition was applied onto a PP plate by an applicator so that the film thickness after drying would be 60 μm. After drying at a temperature of 23° C. for 30 minutes and baking at 100° C. for 30 minutes, the coating film was peeled from the plate. The residual film rate (gel fraction) when immersed in acetone at 23° C. for 24 hours was measured.
<Evaluation criteria>
◯: Gel fraction is 90% or more Δ: Gel fraction is 80% or more and less than 90% ×: Gel fraction is less than 80%

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

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

[Examples 1 to 9 and Comparative Examples 1 to 4]
Using the blocked polyisocyanate compositions A to M obtained in Synthesis Examples 2 to 14, the curability, compatibility, and storage stability at low temperature were evaluated. The results obtained are shown in Table 1.

The blocked polyisocyanate composition of the present invention contains the specific bonding group in the blocking agent in a specific ratio, and thus is excellent in low-temperature curability, compatibility, and storage stability at low temperatures. Therefore, it exhibits excellent performance as a paint, an adhesive, an adhesive, an ink, a sealing agent, a casting agent, a sealing agent, a surface modifier, a coating agent, and the like.

Claims (6)

In a polyisocyanate obtained from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, at least a part of the isocyanate groups contained is a blocking agent containing a malonic acid diester compound and an acetoacetic acid ester compound. A blocked polyisocyanate, and
Contains a monohydric alcohol compound,
(A)/((a)+(b)+(c))=0.020 when the mole numbers of the following three bonds contained in the blocked polyisocyanate are respectively (a) to (c): Or more and less than 0.50,
Blocked polyisocyanate composition:
(A) Urethane bond between isocyanate group and monohydric alcohol compound (b) Bond between isocyanate group and malonic acid diester compound (c) Bond between isocyanate group and acetoacetic acid ester compound. The blocked polyisocyanate composition according to claim 1, wherein the monohydric alcohol compound is a primary alcohol having 3 to 10 carbon atoms. The blocking agent is diethyl malonate Oyo a beauty A Seto ethyl acetate, blocked polyisocyanate composition according to claim 1 or 2. The diisocyanate, hexamethylene diisocyanate, blocked polyisocyanate composition according to any one of claims 1-3. A blocked polyisocyanate composition according to any one of claims 1-4, and a polyvalent active hydrogen compound, thermosetting composition. A method for producing a cured product, which comprises the step of heating and curing the thermosetting composition according to claim 5 .