JP7287795B2 - Block polyisocyanate composition, water-based coating composition and coating film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a blocked polyisocyanate composition, a water-based coating composition and a coating film.

In a two-component polyurethane coating composition using a polyisocyanate composition derived from an aliphatic diisocyanate as a curing agent, the resulting coating film exhibits excellent performance such as weather resistance and chemical resistance. It is used in a wide range of fields such as paints, inks, adhesives, and adhesives. Among the curing agents for two-component polyurethane coating compositions, polyisocyanate compositions derived from hexamethylene diisocyanate (hereinafter sometimes abbreviated as "HDI") are easy to obtain industrially and have excellent weather resistance. It is widely used because of its superiority.

In recent years, from the viewpoint of environmental protection, it is desired that the cross-linkable two-component polyurethane coating composition used as a solvent-based coating be water-based. However, the polyisocyanate composition used as the curing agent in the two-component polyurethane coating composition is difficult to disperse in water. Therefore, the development of polyisocyanate compositions having hydrophilic groups is underway (see, for example, Patent Documents 1 and 2).

Moreover, from the viewpoint of ease of handling, there is a demand for a one-liquid type paint whose physical properties do not change even when the main agent and the curing agent are mixed. By protecting the isocyanate group of the curing agent with a blocking agent and applying heat after on-site coating, the isocyanate group regenerates and reacts with the hydroxyl group of the main polyol to form a thermosetting coating film. Solvent-type blocked isocyanate compositions are mainly used, but water-based compositions are desired from the viewpoint of environmental protection.

For a water-dispersible blocked polyisocyanate composition, a known technique is to introduce at least one ionic hydrophilic group selected from the group consisting of nonionic and cationic groups into the polyisocyanate (see, for example, Patent Documents 3rd class). Patent Document 3 discloses that a blocked polyisocyanate into which a cationic group is introduced can be cured at a low temperature when blended with a coating material.

WO 01/88006 WO2016/104485 Japanese Patent No. 5344875

However, the blocked polyisocyanate described in Patent Document 3 is insufficient in dispersibility in water and curability, and there is room for improvement. In addition, verification of water resistance when used as a coating film and compatibility with a water-based main agent have not been made.

The present invention has been made in view of the above circumstances, and is a blocked polyisocyanate that is easily dispersible in water, has excellent compatibility with the main agent, and exhibits good curability and water resistance when used as a coating film. A composition is provided. A water-based coating composition and coating film using the blocked polyisocyanate composition are provided.

That is, the present invention includes the following aspects.
The blocked polyisocyanate composition according to the first aspect of the present invention comprises (A) an isocyanate component containing at least one isocyanate compound selected from the group consisting of aliphatic diisocyanates and polyisocyanates derived from the aliphatic diisocyanates; (B) a hydrophilic compound containing an active hydrogen group, (C) at least one polyol selected from the group consisting of a bifunctional polyester polyol and a bifunctional polyether polyol, and (D) a block obtained from a pyrazole compound A polyisocyanate composition that satisfies the following conditions (1) to (3).
(1) The mass ratio ((A)/(B)) of the structural unit derived from the isocyanate component (A) to the structural unit derived from the active hydrogen group-containing hydrophilic compound (B) is 50/50 or more and 90/10. is the following;
(2) The content of structural units derived from the (C) polyol is 1% by mass or more and 20% by mass or less with respect to the total mass of the blocked polyisocyanate composition;
(3) There are substantially no free isocyanate groups in the isocyanate component (A).
The (C) polyol may have a number average molecular weight of 300 or more and 3,000 or less.

A water-based coating composition according to the second aspect of the present invention comprises the blocked polyisocyanate composition according to the first aspect and one or more main agents.

The coating film according to the third aspect of the present invention is obtained by curing the water-based coating composition according to the second aspect.

According to the blocked polyisocyanate composition of the above aspect, a blocked polyisocyanate composition that is easily dispersible in water, has excellent compatibility with the main agent, and has good curability and water resistance when formed into a coating film is provided. can do.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "this embodiment") for implementing this invention is demonstrated in detail. In addition, the present invention is not limited to the following embodiments. The present invention can be modified appropriately within the scope of its gist.

As used herein, "polyol" means a compound having two or more hydroxyl groups (--OH).

As used herein, the term "polyisocyanate" means a reactant in which a plurality of monomeric compounds (monomers) having one or more isocyanate groups (--NCO) are combined.

<<Blocked polyisocyanate composition>>
The blocked polyisocyanate composition of this embodiment is obtained from the following components (A) to (D).
(A) an isocyanate component containing at least one isocyanate compound selected from the group consisting of an aliphatic diisocyanate and a polyisocyanate derived from the aliphatic diisocyanate (hereinafter simply abbreviated as "(A) isocyanate component") );
(B) an active hydrogen group-containing hydrophilic compound;
(C) at least one polyol selected from the group consisting of bifunctional polyester polyols and bifunctional polyether polyols (hereinafter sometimes simply abbreviated as "(C) polyol");
(D) pyrazole compound

That is, the blocked polyisocyanate composition of the present embodiment contains the reactants of the above components (A) to (D), and specifically includes (A) the isocyanate component and (B) the active hydrogen group-containing hydrophilic compound. A structural unit derived from and (C) a structural unit derived from a polyol are introduced, and at least a portion of the isocyanate groups of the (A) isocyanate component are blocked with (D) a pyrazole compound.

Further, the blocked polyisocyanate composition of the present embodiment satisfies the following conditions (1) to (3).
(1) The mass ratio ((A)/(B)) of the structural unit derived from the isocyanate component (A) to the structural unit derived from the active hydrogen group-containing hydrophilic compound (B) is 50/50 or more and 90/10. is the following;
(2) The content of structural units derived from the (C) polyol is 1% by mass or more and 20% by mass or less with respect to the total mass of the blocked polyisocyanate composition;
(3) There are substantially no free isocyanate groups in the isocyanate component (A).

Regarding condition (1), the lower limit of (A)/(B) is 50/50, preferably 55/45, more preferably 60/40. On the other hand, the upper limit of (A)/(B) is 90/10 or less, preferably 85/15, more preferably 80/20.
That is, (A)/(B) is 50/50 or more and 90/10 or less, preferably 55/45 or more and 85/15 or less, and more preferably 60/40 or more and 80/20 or less.
When (A)/(B) is within the above range, the blocked polyisocyanate is easily dispersible in water, has excellent compatibility with the main agent, and exhibits good curability and water resistance when formed into a coating film. A composition can be provided.

(A)/(B) can be calculated by ¹ H-NMR measurement.
As a specific measurement method, first, a _CDCl3 solution of the polyisocyanate composition is prepared. Then, the resulting solution is subjected to ¹ H-NMR measurement under the following measurement conditions to confirm (A) methylene groups derived from the isocyanate component and (B) methylene groups derived from the active hydrogen group-containing hydrophilic compound. The characteristic peaks (chemical shift values) of each composition are (A) methylene groups derived from the isocyanate component near 1.4 ppm, and (B) methylene groups derived from the active hydrogen group-containing hydrophilic compound near 3.5 ppm. , and (B) the methyl group derived from the active hydrogen group-containing hydrophilic compound is around 3.4 ppm. (A) ¹ H-NMR integral value of methylene group derived from isocyanate component x, (B) ¹ H-NMR integral value of methylene group derived from hydrophilic compound containing active hydrogen group y, (B) active hydrogen group-containing (A)/(B) can be calculated by the following formula, where z is the ¹ H-NMR integral value of the methyl group derived from the hydrophilic compound.

(A)/(B)=(x×168/4)/(y×44/4+z×76/3)

Regarding the condition (2), the content of (C) the structural unit derived from the polyol is 1% by mass or more and 20% by mass or less, and 3% by mass or more and 18% by mass, relative to the total mass of the block polyisocyanate composition. The following are preferable, and 5 mass % or more and 15 mass % or less are more preferable.
(C) When the content of the structural unit derived from the polyol is within the above range, the curability of the coating film tends to be good.
(C) The content of structural units derived from a polyol can be measured using the method described in Examples below.

Regarding the condition (3), the isocyanate group of the (A) isocyanate component contained in the blocked polyisocyanate composition of the present embodiment reacts with the active hydrogen group of the (B) active hydrogen group-containing hydrophilic compound to form a bond. or (C) reacts with the hydroxyl group of the polyol to form a urethane bond, or (D) is blocked with a pyrazole-based compound, and (A) the free isocyanate group of the isocyanate component is substantially present. do not. Therefore, the blocked polyisocyanate composition of the present embodiment, while having stable dispersibility in water, does not react even when mixed with water or the main agent, and can be subjected to a treatment such as heating to prevent the isocyanate group from reacting. can be regenerated and cured. The term "free isocyanate group" as used herein means that (B) the active hydrogen group of the hydrophilic compound containing an active hydrogen group and (C) the hydroxyl group of the polyol have not reacted, and (D) the pyrazole-based compound and the like have not reacted. Indicates an isocyanate group that is not blocked by a blocking agent, and means an isocyanate group that retains reactivity with water or an active hydrogen group of the main agent. In addition, the phrase "substantially free of free isocyanate groups" means a state in which there are no free isocyanate groups at all, or a very small amount of free isocyanate groups that does not impede the effects of the blocked polyisocyanate composition of the present embodiment. As shown in Examples described later, it means a state in which characteristic absorption of isocyanate groups does not exist in measurement by infrared spectrum using a blocked polyisocyanate composition as a sample.

The blocked polyisocyanate composition of the present embodiment having the above structure can be easily dispersed in water, has excellent compatibility with the main agent, and provides a coating film having good curability and water resistance.
The constituent components of the blocked polyisocyanate composition of the present embodiment are described in detail below.

<(A) isocyanate component>
(A) The isocyanate component contains at least one isocyanate compound selected from the group consisting of aliphatic diisocyanates and polyisocyanates derived from the aliphatic diisocyanates.

Aliphatic diisocyanates include, but are not limited to, 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, ethyl (2,6-diisocyanato)hexanoate, HDI, 1,9- diisocyanatononane, 1,12-diisocyanatododecane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, and the like. These aliphatic diisocyanates may be used singly or in combination of two or more.
(A) As the isocyanate component, an alicyclic diisocyanate may be used in addition to the aliphatic diisocyanate. Alicyclic diisocyanates include, for example, 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane (hereinafter sometimes abbreviated as "hydrogenated XDI"), 1,3- or 1,4- Diisocyanatocyclohexane, 3,5,5-trimethyl 1-isocyanato-3-(isocyanatomethyl)cyclohexane (hereinafter sometimes abbreviated as "IPDI"), 4-4'-diisocyanato-dicyclohexylmethane (hereinafter, may be abbreviated as "hydrogenated MDI"), 2,5- or 2,6-diisocyanatomethylnorbornane, and the like. These alicyclic diisocyanates may be used singly or in combination of two or more.
In addition to the above aliphatic diisocyanate, aliphatic triisocyanate may also be used as the (A) isocyanate component. Examples of aliphatic triisocyanates include 1,3,6-triisocyanatohexane, 1,8-diisocyanato-4-isocyanatomethyloctane, 2-isocyanatoethyl-2,6-diisocyanato-hexanoate, and the like. . These aliphatic triisocyanates may be used singly or in combination of two or more.

The polyisocyanate derived from the above aliphatic diisocyanate is not limited to the following, for example, polyisocyanate having a uretdione structure obtained by cyclodimerization of two isocyanate groups, cyclization of three isocyanate groups A polyisocyanate having an isocyanurate structure obtained by trimerization, a polyisocyanate having an iminooxadiazinedione structure obtained by cyclotrimerization of three isocyanate groups, and reacting three isocyanate groups with one water molecule. A polyisocyanate having a biuret structure obtained by reacting two isocyanate groups with one molecule of carbon dioxide, a polyisocyanate having an oxadiazinetrione structure obtained by reacting one molecule of carbon dioxide, one isocyanate group and one hydroxyl group reacting A polyisocyanate having a urethane group obtained by reacting two isocyanate groups and one hydroxyl group, a polyisocyanate having an allophanate structure obtained by reacting one hydroxyl group, and an acyl urea obtained by reacting one isocyanate group and one carboxyl group. polyisocyanate having a group, polyisocyanate having a urea structure obtained by reacting one isocyanate group with one primary or secondary amine, and the like. These polyisocyanates may be used singly or in combination of two or more. In addition, the "polyisocyanate" as used herein includes, in addition to the polyisocyanate derived only from the above-mentioned aliphatic diisocyanate, the above-mentioned aliphatic diisocyanate and a compound other than the diisocyanate (e.g., alcohol such as monoalcohol, water, amine). Polyisocyanates obtained by reacting with are also included.

<(B) Active Hydrogen Group-Containing Hydrophilic Compound>
(B) Active hydrogen group-containing hydrophilic compounds include, but are not limited to, nonionic hydrophilic compounds, anionic hydrophilic compounds, cationic hydrophilic compounds, and the like. Among them, a nonionic hydrophilic compound or an anionic hydrophilic compound is preferable, and a nonionic hydrophilic compound is more preferable, from the viewpoint of ease of production. These active hydrogen group-containing hydrophilic compounds may be used singly or in combination of two or more.

[Nonionic hydrophilic compound]
Examples of nonionic hydrophilic compounds include poly(oxyalkylene) monoalkyl ethers. Among them, from the viewpoint of lowering the viscosity of the block polyisocyanate composition, as the poly(oxyalkylene) monoalkyl ether, a compound represented by the following general formula (I) (hereinafter sometimes referred to as "compound (I)" is) is preferable.

In general formula (I), R ¹¹ is an alkylene group having 1 to 4 carbon atoms, and R ¹² is an alkyl group having 1 to 4 carbon atoms.
In addition, polyalkylene glycol alkyl ether is not a single component, but an aggregate of substances with different numbers of n11 indicating the degree of polymerization of alkylene oxide (hereinafter sometimes referred to as "degree of polymerization n11" or simply "n11") is. Therefore, in general formula (I), the degree of polymerization n11 of alkylene oxide is represented by the average number (average value). The average number of n11 is 5.0 or more and 20 or less.

・^R11
In general formula (I), R ¹¹ is an alkylene group having 1 to 4 carbon atoms, and is preferably an alkylene group having 2 carbon atoms, that is, an ethylene group, from the viewpoint of imparting hydrophilicity.

・^R12
In general formula (I), R ¹² is an alkyl group having 1 to 4 carbon atoms, and is preferably an alkyl group having 1 carbon atoms, that is, a methyl group, from the viewpoint of imparting hydrophilicity.

・n11
The lower limit of the average number of n11 is 5.0, preferably 5.2, more preferably 5.4, more preferably 6.0, from the viewpoint of water dispersibility, water dispersion stability and coating appearance. preferable. On the other hand, the upper limit is 20, preferably 18, more preferably 16, from the viewpoint of coating film hardness.
That is, the average number of n11 is 5.0 or more and 20 or less, preferably 5.2 or more and 18 or less, more preferably 5.4 or more and 16 or less, and even more preferably 6.0 or more and 16 or less.
When the average number of n11 is at least the above lower limit, the emulsifying power is further increased, so that the dispersibility is further improved and the dispersibility can be more easily dispersed. Therefore, the dispersibility in the main agent is further improved, and the appearance of the coating film tends to be more excellent. On the other hand, when the average number of n11 is equal to or less than the above upper limit, excessive increase in viscosity such as gelation can be more prevented, and dispersion tends to be easier. Furthermore, the hardness of the coating film tends to be more excellent.

From the viewpoint of dispersibility, the lower limit of the number average molecular weight of the poly(oxyalkylene) monoalkyl ether is preferably 200, more preferably 300, and even more preferably 400. On the other hand, the upper limit is preferably 2000, more preferably 1200, and even more preferably 1000, from the viewpoint of the hardness of the coating film.
That is, the number average molecular weight of the poly(oxyalkylene) monoalkyl ether is preferably 200 or more and 2000 or less, more preferably 300 or more and 1200 or less, and even more preferably 400 or more and 1000 or less.

Commercially available poly(oxyalkylene) alkyl ethers include, for example, trade names "UNIOX M400", "UNIOX M550", "UNIOX M1000" and "UNIOX M2000" manufactured by NOF Corporation, and Nippon Emulsifier Co., Ltd. product names such as "MPG-081" and "MPG-130" manufactured by

(A) The amount of poly(oxyalkylene) monoalkyl ether introduced into the isocyanate component can be calculated, for example, using the following method.
Specifically, using the blocked polyisocyanate composition of the present embodiment as a sample, at 220 nm in liquid chromatography (LC), an unintroduced polyisocyanate, a monofunctional polyalkylene oxide polyether alcohol introduced poly It can be determined from the peak area ratios of the isocyanate, the two introduced polyisocyanates, and the three or more introduced polyisocyanates. Examples of LC measurement conditions include the following.

(Measurement condition)
LC device: UPLC (trade name) manufactured by Waters
Column: Waters, ACQUITY UPLC HSS T3 1.8 μm C18 inner diameter 2.1 mm × length 50 mm
Flow rate: 0.3mL/min
Mobile phase: A = 10 mM ammonium acetate aqueous solution, B = acetonitrile Gradient conditions: The initial mobile phase composition was A/B = 98/2, the ratio of B was linearly increased after sample injection, and A/ B=0/100.
Detection method: photodiode array detector, measurement wavelength is 220 nm

The blocked polyisocyanate composition of the present embodiment has good water dispersibility by introducing hydrophilic groups (polyalkylene oxide units) derived from poly(oxyalkylene) monoalkyl ether into the (A) isocyanate component. have
In this specification, the term "water-dispersible" means the property of being able to disperse in water so that the block polyisocyanate composition is of O/W type. Water dispersibility is determined, for example, by adding a blocked polyisocyanate composition to water and mechanically stirring it with a stick, a hand mixer, etc., as shown in the examples below, to determine whether or not the composition is dispersed in water. can be evaluated by checking The term "O/W type" as used herein means an emulsion of oil droplets in water having a continuous phase of water.

[Anionic hydrophilic compound]
Examples of anionic hydrophilic compounds include carboxylic acid group-containing compounds and sulfonic acid group-containing compounds. Among them, as the anionic hydrophilic compound, a carboxylic acid group-containing compound is preferable from the viewpoint of ease of production and blendability in a water-based paint. Examples of carboxylic acid group-containing compounds include monohydroxycarboxylic acids, dihydroxycarboxylic acids, derivatives thereof, and the like. Among them, monohydroxycarboxylic acid or dihydroxycarboxylic acid is preferable, and monohydroxycarboxylic acid is more preferable.

When a carboxylic acid group-containing compound or a sulfonic acid group-containing compound is used as (B) the active hydrogen group-containing hydrophilic compound, it is preferable to neutralize with a neutralizing agent after production of the block polyisocyanate composition. Examples of neutralizing agents include alkali metals, alkaline earth metals, ammonia, and tertiary amines. Tertiary amines include, for example, trimethylamine, triethylamine, dimethylethanolamine, and the like.

[Cationic hydrophilic compound]
Examples of cationic hydrophilic compounds include hydroxyl group-containing amino compounds.
When a hydroxyl group-containing amino compound is used as (B) the active hydrogen group-containing hydrophilic compound, it is preferable to neutralize with a neutralizing agent after production of the block polyisocyanate composition. Examples of neutralizing agents include organic acids such as acetic acid, propionic acid, butanoic acid, and 2-ethylhexanoic acid.

<(C) Polyol>
(C) Polyol is at least one polyol selected from the group consisting of bifunctional polyether polyols and bifunctional polyester polyols.

The bifunctional polyether polyol is not particularly limited, but for example, using a catalyst, an alkylene oxide alone or a mixture, a divalent hydroxy compound alone or a mixture, at least selected from the group consisting of random addition and block addition Bifunctional polyether polyols obtained by addition polymerization of one type; Bifunctional polyether polyols obtained by reacting a diamine compound with alkylene oxide; Acrylamide or the like is polymerized using these bifunctional polyether polyols as a medium. So-called bifunctional polymer polyols obtained by
Examples of the catalyst include alkali metal hydroxides, strongly basic catalysts, double metal cyanide complexes, and the like. Alkali metals include, for example, lithium, sodium, potassium and the like. Examples of strongly basic catalysts include alcoholates, alkylamines, and the like. Examples of double metal cyanide complexes include metal porphyrins and zinc hexacyanocobaltate complexes.
Examples of alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide.
Examples of diamine compounds include ethylenediamines and the like.

The bifunctional polyester polyol is not particularly limited. Examples thereof include bifunctional polycaprolactones obtained by ring polymerization.
Examples of dicarboxylic acids include succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid.
Examples of bifunctional alcohols include ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol and the like.

(C) The number average molecular weight of the polyol is preferably 300 or more and 3000 or less, more preferably 350 or more and 2500 or less, and even more preferably 400 or more and 2000 or less. Flexibility and workability tend to be more excellent when the number average molecular weight is within the above range. The number average molecular weight can be measured by the method described in Examples below.

<(D) Pyrazole Compound>
In the blocked polyisocyanate composition of the present embodiment, at least part of the isocyanate groups of the (A) isocyanate component are blocked with (D) the pyrazole compound. Examples of pyrazole compounds include pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole and the like. These pyrazole compounds may be used singly or in combination of two or more. Among them, 3,5-dimethylpyrazole is preferred as the pyrazole compound (D) because it tends to exhibit better curability in low-temperature or short-time drying.

<Organic solvent>
The blocked polyisocyanate composition of this embodiment can further contain an organic solvent.
Containing an organic solvent lowers the viscosity of the block polyisocyanate composition, thereby further improving water dispersibility. In addition, when the blocked polyisocyanate composition is dispersed in water, the residual rate of isocyanate groups tends to be higher, and the pot life when used as a water-based coating composition tends to be further improved.

Any organic solvent may be used as long as it does not have a functional group that reacts with an isocyanate group and is compatible with the blocked polyisocyanate composition.
Examples of such organic solvents include ester compounds, ether compounds, ketone compounds, aromatic compounds, polyethylene glycol dialkyl ether compounds, and polyethylene glycol dicarboxylate compounds. Examples of ester compounds include butyl acetate, isobutyl acetate, pentyl acetate, methoxypropyl acetate, 3-methoxybutyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, butyl propionate, butyl butyrate, and dioctyl adipate. , diisopropyl glutarate and the like. Ether compounds include, for example, diisopropyl ether, dibutyl ether, dioxane, diethoxyethane and the like. Ketone compounds include, for example, 2-pentanone, 3-pentanone, 2-hexanone, methylisobutylketone, 2-heptanone, 4-heptanone, diisobutylketone, isophorone, cyclohexanone, methylcyclohexanone and the like. Examples of aromatic compounds include benzene, toluene, xylene, ethylbenzene, butylbenzene, p-cymene and the like. Examples of polyethylene glycol dialkyl ether compounds include diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and diethylene glycol dibutyl ether. Examples of polyethylene glycol dicarboxylate compounds include diethylene glycol diacetate.

The lower limit of the content of the organic solvent in the blocked polyisocyanate composition of the present embodiment is preferably 1% by mass, more preferably 3% by mass, and 5% by mass with respect to the total mass of the blocked polyisocyanate composition. More preferred. On the other hand, the upper limit of the organic solvent content is preferably 70% by mass, more preferably 60% by mass, and even more preferably 50% by mass, relative to the total mass of the block polyisocyanate composition.
That is, the content of the organic solvent in the blocked polyisocyanate composition of the present embodiment is preferably 1% by mass or more and 70% by mass or less, and 3% by mass or more and 60% by mass, relative to the total mass of the blocked polyisocyanate composition. The following are more preferable, and 5% by mass or more and 50% by mass or less are even more preferable.
When the content of the organic solvent is within the above range, the viscosity of the block polyisocyanate composition is further lowered, the pot life of the water-based coating composition is further improved, and the content of the organic solvent is increased. Too much can be more effectively suppressed.

<Method for producing blocked polyisocyanate composition>
Although the blocked polyisocyanate composition of the present embodiment is not particularly limited, (A) an isocyanate component, (B) an active hydrogen group-containing hydrophilic compound, (C) a polyol, and (D) a pyrazole compound are reacted. obtained by letting
(A) the reaction between the isocyanate group of the isocyanate component and (B) the active hydrogen group-containing hydrophilic reactant and (C) the polyol, and (A) the reaction between the isocyanate group of the isocyanate component and (D) the pyrazole compound. They can be carried out simultaneously, or one of the reactions can be carried out in advance and then the second reaction can be carried out. Among them, (A) the isocyanate component, (B) the active hydrogen group-containing hydrophilic reactant, and (C) the polyol are first reacted, and then (D) the pyrazole compound is reacted. preferable.
In addition, as the isocyanate component (A), an aliphatic diisocyanate may be used in the reaction, or a polyisocyanate previously derived from an aliphatic diisocyanate may be used in the reaction.

In the reaction step, an organic metal salt, a tertiary amine compound, or an alkali metal alcoholate may be used as a catalyst. Examples of metals contained in organic metal salts include tin, zinc, and lead. Examples of alkali metals include sodium and the like.
The reaction temperature in the reaction step is preferably −20° C. or higher and 150° C. or lower, more preferably 30° C. or higher and 100° C. or lower. When the reaction temperature is equal to or higher than the above lower limit, the reactivity tends to be higher. On the other hand, when the reaction temperature is equal to or lower than the above upper limit, side reactions tend to be more effectively suppressed.

It is preferred that the active hydrogen group-containing hydrophilic compound (B) is completely reacted with the isocyanate component (A) so that it does not remain in an unreacted state. By not remaining in an unreacted state, the water dispersion stability of the blocked polyisocyanate composition of the present embodiment is further improved, and the decrease in curability when used as a water-based coating composition tends to be more effectively suppressed. be.

<Physical properties of blocked polyisocyanate composition>
[Effective isocyanate group (NCO) content]
In the blocked polyisocyanate composition of the present embodiment, the effective NCO content is not particularly limited, but is preferably 1% by mass or more and 15% by mass or less because the storage stability of the blocked polyisocyanate composition is improved. It is more preferably 2% by mass or more and 10% by mass or less, and even more preferably 3% by mass or more and 9% by mass or less.
Incidentally, the effective NCO content can be calculated using the method described in the examples below.

<Application>
The blocked polyisocyanate composition of the present embodiment can be used as a curing agent for coating compositions (in particular, water-based two-component polyurethane coating compositions).
In addition, the blocked polyisocyanate composition of the present embodiment includes, for example, curable compositions such as pressure-sensitive adhesive compositions, adhesive compositions and casting compositions; various surface treatment compositions such as fiber treatment agents; Elastomer compositions; cross-linking agents for foam compositions; modifiers; additives and the like.
The pressure-sensitive adhesive composition and adhesive composition containing the blocked polyisocyanate composition of the present embodiment are not particularly limited, but are used, for example, in automobiles, building materials, home appliances, wood products, solar cell laminates, and the like. Among them, optical members for liquid crystal displays of home electric appliances such as televisions, personal computers, digital cameras, mobile phones, etc. exhibit various functions, so it is necessary to laminate films and plates of various adherends. Therefore, since sufficient adhesiveness or adhesiveness is required between films and plates of various adherends, the adhesive composition and adhesive composition containing the blocked polyisocyanate composition of the present embodiment are It is suitably used for bonding optical members such as those for liquid crystal displays of home appliances.

≪Water-based paint composition≫
The water-based coating composition of the present embodiment contains the blocked polyisocyanate composition and one or more main agents. By having the above configuration, the water-based coating composition of the present embodiment has excellent compatibility between the blocked polyisocyanate composition as a curing agent and the main agent, and a coating film having good curability and water resistance can be obtained.

<Main agent>
A water-based polyol is preferable as the main agent used in the water-based coating composition. The water-based polyol includes all those expressed as latexes, emulsions, dispersions, and water-soluble resins containing hydroxyl groups. Specific examples of aqueous polyols include polyvinylidene chloride copolymers, polyvinyl chloride copolymers, vinyl acetate copolymers, water-soluble acrylic resins, water-soluble polyester resins, urethane dispersions, acrylic emulsions, fluorine copolymers, Coalesced emulsions, styrene-butadiene copolymer latexes, acrylonitrile-butadiene copolymers, rubber latexes, polybutadiene copolymers, urethane-acrylic emulsions, copolymers or mixtures thereof, and the like.
Among them, as the water-based polyol, those expressed as latex, emulsion or dispersion are preferable because they are excellent in operability and water resistance. Among them, an acrylic emulsion, a fluorocopolymer emulsion, a urethane dispersion, or a polymer thereof is particularly preferable because it is particularly excellent in weather resistance, gloss and toughness when formed into a coating film.

When using aqueous polyols expressed as latex, emulsion or dispersion, the lower limit of the particle size is preferably 5 nm, more preferably 10 nm, and even more preferably 40 nm. On the other hand, the upper limit of the particle size is preferably 1.0 μm, more preferably 500 nm, and even more preferably 300 nm.
That is, the particle diameter is preferably 5 nm or more and 1.0 μm or less, more preferably 10 nm or more and 500 nm or less, and even more preferably 40 nm or more and 300 nm or less.
When the particle size is within the above range, the coating film has a higher gloss and is more excellent in water resistance. Also, the stability as a latex, emulsion or dispersion becomes more sufficient.

The lower limit of the hydroxyl value of the aqueous polyol is preferably 1 mgKOH/g, more preferably 5 mgKOH/g, even more preferably 10 mgKOH/g. On the other hand, the upper limit of the hydroxyl value is preferably 300 mgKOH/g, more preferably 200 mgKOH/g, even more preferably 150 mgKOH/g.
That is, the hydroxyl value of the aqueous polyol is preferably 1 mgKOH/g or more and 300 mgKOH/g or less, more preferably 5 mgKOH/g or more and 200 mgKOH/g or less, and even more preferably 10 mgKOH/g or more and 150 mgKOH/g or less.
When the hydroxyl value of the aqueous polyol is within the above range, the cross-linking points become more sufficient, and a more flexible and tough coating film can be obtained.

In the coating composition of the present embodiment, the lower limit of the molar ratio of the isocyanate groups of the polyisocyanate composition to the hydroxyl groups of the aqueous polyol (isocyanate groups/hydroxyl groups) is preferably 0.3, more preferably 0.5, and 0 .6 is more preferred. On the other hand, the upper limit of the molar ratio is preferably 5.0, more preferably 3.0, and even more preferably 2.5.
That is, the molar ratio of the isocyanate groups of the polyisocyanate composition to the hydroxyl groups of the aqueous polyol (isocyanate groups/hydroxyl groups) is preferably 0.3 or more and 5.0 or less, more preferably 0.5 or more and 3.0 or less, and 0 .6 or more and 2.5 or less is more preferable.
When the molar ratio (isocyanate group/hydroxyl group) is within the above range, the cross-linking points become more sufficient, and a more flexible and tough coating film can be obtained.

<Other additives>
In addition to the blocked polyisocyanate composition and the main agent, the water-based coating composition of the present embodiment can contain various known and commonly used coating additives depending on the application, method of use, and the like. Paint additives include, for example, thickeners, leveling agents, thixotropic agents, antifoaming agents, freeze stabilizers, matting agents, crosslinking reaction catalysts, anti-skinning agents, dispersants, wetting agents, and light stabilizers. , antioxidants, ultraviolet absorbers, fillers, plasticizers, lubricants, reducing agents, preservatives, antifungal agents, deodorants, anti-yellowing agents, antistatic agents, charge control agents and the like. These additives can be appropriately selected and used within a range that does not impair the effects exhibited by the water-based coating composition of the present embodiment.

<Method for producing a water-based coating composition>
The water-based paint composition of the present embodiment is prepared, for example, by first adding the paint additives described above to an aqueous dispersion of the main agent or an aqueous solution thereof, if necessary. Next, the block polyisocyanate composition is added as a curing agent, and if necessary, water or a solvent is further added. Then, by forcibly stirring using a stirrer, a water-based coating composition can be obtained.

<Application>
The water-based coating composition of the present embodiment is not limited to the following, but for example, by a coating method such as roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, etc. An object to be coated by molding various materials. It is suitable for use as a primer, intermediate coating or top coating for coating. It is also useful as a paint for imparting cosmetic properties, weather resistance, acid resistance, rust resistance, chipping resistance, etc. to precoated metals including rust-proof steel plates, automobiles, and plastics. It is also useful as a urethane raw material for adhesives, adhesives, elastomers, foams, surface treatment agents and the like.

Materials to be coated with the water-based coating composition include glass; various metals such as aluminum, iron, zinc steel plate, copper, and stainless steel; porous members such as wood, paper, mortar, and stone; Materials coated with urethane coating, acrylic urethane coating, etc.; Sealant cured products such as silicone-based cured products, modified silicone-based cured products, and urethane-based cured products; Rubbers such as vinyl chloride, natural rubber, and synthetic rubber; Natural leather , Leathers such as artificial leather; Fibers such as plant fibers, animal fibers, carbon fibers, glass fibers; Films and plates of resins such as non-woven fabrics, polyester, acrylic, polycarbonate, triacetyl cellulose, polyolefin; UV curing type acrylic resin layer; layers made of inks such as printing inks and UV inks;

≪Paint film≫
The coating film of this embodiment is obtained by curing the water-based coating composition. The coating film of this embodiment has good curability and water resistance.

The coating film of the present embodiment is obtained by applying the water-based coating composition to an adherend and drying it. Examples of the coating method include the same methods as those described in the application of the water-based coating composition. Examples of the adherend include those similar to the objects to be coated described in the application of the water-based coating composition.

Hereinafter, the present embodiment will be described in more detail by showing specific examples and comparative examples, but the present embodiment is not limited by the following examples and comparative examples as long as the gist thereof is not exceeded. . Various physical properties and evaluations in Examples and Comparative Examples were measured and evaluated as follows.

<Method for measuring physical properties>
[Physical properties 1] Isocyanate group (NCO) content of polyisocyanate (% by mass)
1 to 3 g of polyisocyanate was accurately weighed (Wg) into an Erlenmeyer flask. Then, 20 mL of toluene was added to the Erlenmeyer flask to dissolve the polyisocyanate. Next, 10 mL of a toluene solution of 2N di-n-butylamine was added, and after mixing, the mixture was allowed to stand at room temperature for 15 minutes. Then, 70 mL of isopropyl alcohol was added to the Erlenmeyer flask and mixed. This liquid was titrated with an indicator with a 1N hydrochloric acid solution (Factor F). This titration value was defined as V2mL.
Then, the same operation was performed without polyisocyanate, and the titration value was set to V1 mL. Next, the NCO content of the polyisocyanate was calculated according to the formula shown below.

NCO content (mass%) = (V1-V2) x F x 42/(W x 1000) x 100

[Physical property 2] Non-volatile content The non-volatile content of the blocked polyisocyanate composition was determined as follows. First, after accurately weighing an aluminum dish with a bottom diameter of 38 mm, about 1 g of each block polyisocyanate component was placed on the aluminum dish and accurately weighed (W1). Then, after adjusting the blocked polyisocyanate component to have a uniform thickness, it was held in an oven at 105° C. for 1 hour. Then, after the aluminum dish reached room temperature, the blocked polyisocyanate component remaining in the aluminum dish was precisely weighed (W2). Then, the non-volatile content of the blocked polyisocyanate component was calculated according to the formula shown below.

Non-volatile content (mass%) = W2/W1 x 100

[Physical Property 3] Effective Isocyanate Group (NCO) Content The effective NCO content of the block polyisocyanate composition was determined as follows. The effective NCO content (% by mass) as used herein is used to quantify the amount of blocked isocyanate groups present in the blocked polyisocyanate component after the blocking reaction and capable of participating in the cross-linking reaction. is represented as The effective NCO content was calculated by the formula shown below. In the formula shown below, "S" represents the non-volatile content (% by mass) of the block polyisocyanate component. "W1" represents the mass (g) of polyisocyanate used in the reaction. "A" represents the isocyanate group content (% by mass) of the polyisocyanate. "W2" represents the mass (g) of the blocked polyisocyanate after the blocking reaction.

Effective NCO content (% by mass) = {S x (W1 x A)}/W2

[Physical properties 4] (A)/(B)
The mass ratio ((A)/(B)) of the structural unit derived from the isocyanate component (A) to the structural unit derived from the active hydrogen group-containing hydrophilic compound (B) was calculated by ¹ H-NMR measurement.
As a specific measurement method, first, a _CDCl3 solution of a polyisocyanate composition was prepared. Then, the resulting solution was subjected to ¹ H-NMR measurement under the following measurement conditions to confirm (A) methylene groups derived from the isocyanate component and (B) methylene groups derived from the active hydrogen group-containing hydrophilic compound. The characteristic peaks (chemical shift values) of each composition are (A) methylene groups derived from the isocyanate component near 1.4 ppm, and (B) methylene groups derived from the active hydrogen group-containing hydrophilic compound near 3.5 ppm. , (B) The methyl group derived from the active hydrogen group-containing hydrophilic compound was around 3.4 ppm. (A) ¹ H-NMR integral value of methylene group derived from isocyanate component x, (B) ¹ H-NMR integral value of methylene group derived from hydrophilic compound containing active hydrogen group y, (B) active hydrogen group-containing (A)/(B) was calculated by the following formula, where z is the ¹ H-NMR integral value of the methyl group derived from the hydrophilic compound.

(A)/(B)=(x×168/4)/(y×44/4+z×76/3)

[Physical property 5] (C) Content of structural units derived from polyol (C) Content of structural units derived from polyol is (A) isocyanate component (B) active hydrogen group-containing hydrophilic compound, (C) polyol , and (D) the compounding amount of the pyrazole compound, it was calculated by the following formula. In the formulas below, (A) to (D) represent the compounding amounts (g) of the respective components.

(C) Content of structural units derived from polyol (% by mass)
= (C) / ((A) + (B) + (C) + (D)) x 100

<Evaluation method>
[Production of water-based one-component polyurethane coating composition]
For the blocked polyisocyanate compositions obtained in Examples and Comparative Examples, the aqueous acrylic resin dispersion obtained in Synthesis Example 4 described later (solid content 42%, resin content hydroxyl value 66 mgKOH/g, acid value 16 mgKOH/g ) were blended so that the functional group ratio (NCO/OH) was 1.0. Further, deionized water was added to this mixture so that the solid content was 40%, and the mixture was stirred at 1000 rpm for 5 minutes using a disper blade to prepare a water-based one-component polyurethane coating composition.

[Evaluation 1] Water Dispersibility A blocked polyisocyanate composition and deionized water were weighed in a glass bottle at a mass ratio of 1:9, and shaken 30 times to obtain a water dispersion. The appearance of the aqueous dispersion was evaluated according to the following evaluation criteria.

(Evaluation criteria)
○: well dispersed, no sediment ×: sediment present

[Evaluation 2] Compatibility with main agent Each water-based one-component polyurethane coating composition was applied on a glass plate and dried to prepare a coating film. Next, the surface appearance of the produced coating film was observed, and the compatibility with the main agent was evaluated according to the following evaluation criteria.

(Evaluation criteria)
○: Appearance is transparent, no turbidity ×: Turbidity and lumps

[Evaluation 3] Curability of Coating Film Each water-based one-component polyurethane coating composition was applied onto a polypropylene plate and dried to prepare a coating film. Then, after immersing the prepared coating film in acetone at 23° C. for 24 hours, the mass of the undissolved portion was divided by the mass before immersion to calculate the ratio (% by mass) of the undissolved portion. The curability of the coating film was evaluated according to the following evaluation criteria.

(Evaluation criteria)
◎: 85% by mass or more ○: 70% by mass or more and less than 85% by mass ×: less than 70% by mass

[Evaluation 4] Water resistance of coating film Each water-based one-liquid type polyurethane coating composition was applied on a glass plate and dried to prepare a coating film. A rubber ring was then placed on the prepared coating film, and deionized water was dripped onto the central portion. After treatment at 23° C. for 24 hours, the water resistance of the coating film was evaluated according to the following criteria based on the state of blisters generated between the glass substrate and the coating film.

(Evaluation criteria)
○: No change in appearance ×: Cloudy and blistering

<(A) Production of isocyanate component>
[Synthesis Example 1] Production of polyisocyanate Pa-1 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube and a dropping funnel is set to a nitrogen atmosphere, HDI: 1000 g is charged, and bifunctional polypropylene Glycol (manufactured by Sanyo Kasei, trade name "Sannics PP-400", number average molecular weight 400) (hereinafter sometimes abbreviated as "PP400"): 85.0 g was charged, and the temperature in the reactor was brought to 100°C while stirring. , and the urethanization reaction was allowed to proceed. Thereafter, tetramethylammonium capriate, which is an isocyanurate reaction catalyst, was added, and when the yield reached 66%, phosphoric acid was added to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporator to obtain polyisocyanate Pa-1. The resulting Pa-1 had an NCO content of 16.7% by mass.

[Synthesis Example 2] Production of polyisocyanate Pa-2 A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube and dropping funnel was set to a nitrogen atmosphere, 1000 g of HDI was charged, and the reaction was carried out with stirring. The temperature inside the vessel was maintained at 80° C., and tetramethylammonium capriate, which is an isocyanurate reaction catalyst, was added, and when the yield reached 41%, phosphoric acid was added to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporator to obtain polyisocyanate Pa-2. The resulting Pa-2 had an NCO content of 21.8% by mass.

[Synthesis Example 3] Production of polyisocyanate Pa-3 A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube and dropping funnel was set to a nitrogen atmosphere, HDI: 1000 g, methyl cellosolve / trimethyl Phosphoric acid=1/1 mixed solution: 333.3 g was charged, the temperature inside the reactor was maintained at 140° C. under stirring, and ion-exchanged water: 13.3 g was added to initiate the reaction. When the yield reached 35%, the temperature was lowered to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed using a thin film evaporator to obtain polyisocyanate Pa-3. The resulting Pa-3 had an NCO content of 22.0% by mass.

<Manufacturing of main agent>
[Synthesis Example 4] Production of acrylic resin aqueous dispersion In a reaction vessel, deionized water: 70 parts by mass, 40% emulsifier aqueous solution: 2 parts by mass, methyl methacrylate: 0.37 parts by mass, n-butyl acrylate: 0.2 parts by mass. 23 parts by mass, n-butyl methacrylate: 0. 24 parts by mass, 2-hydroxyethyl methacrylate: 0.15 parts by mass, and acrylic acid: 0.01 parts by mass were charged, mixed in a nitrogen stream, and 3% ammonium persulfate aqueous solution: 4 parts by mass were added at 60 ° C. rice field. Next, the temperature is raised to 70 ° C., methyl methacrylate: 29 parts by mass, n-butyl acrylate: 18 parts by mass, n-butyl methacrylate: 19 parts by mass, 2-hydroxyethyl methacrylate: 12 parts by mass, acrylic acid: 1 A mixture of parts by mass, 40% aqueous emulsifier solution: 2 parts by mass, 3% aqueous ammonium persulfate solution: 4 parts by mass, and deionized water: 40 parts by mass was added to the reaction solution over 3 hours. Next, while maintaining at 70 ° C., methyl methacrylate: 7.63 parts by mass, n-butyl acrylate: 3.77 parts by mass, n-butyl methacrylate: 4.76 parts by mass, 2-hydroxyethyl methacrylate: 2.85 A mixture of parts by mass, acrylic acid: 0.99 parts by mass, and 3% aqueous ammonium persulfate solution: 4 parts by mass was added to the reaction solution over 2 hours. After aging for 1 hour, 2 parts of deionized water (15 parts by mass) were added to the reaction solution, and the temperature was lowered to 30°C. After neutralization with dimethylethanolamine, an aqueous acrylic resin dispersion with a solid content of 42% was obtained. The acrylic resin aqueous dispersion had a resin component hydroxyl value of 66 mgKOH/g, an acid value of 16 mgKOH/g, a number average molecular weight of 150000, a pH of 7.1, an average particle size of 0.1 µm, and a milky white appearance. . The average particle size is a value measured using an average particle size analyzer (submicron particle size distribution analyzer, trademark “Coulter N4Plus”, manufactured by Beckman Coulter, Inc.).

<Production of block polyisocyanate composition>
[Example 1] Production of blocked polyisocyanate composition BPa-1 Polyisocyanate Pa-1 obtained in Synthesis Example 1: 100 g of the polyisocyanate Pa-1 obtained in Synthesis Example 1 was replaced with nitrogen in a four-necked flask equipped with a stirrer, a thermometer and a cooling tube. , Methoxy polyethylene glycol (MPG-081, ethylene oxide repeating unit: 15, manufactured by Nippon Nyukazai Co., Ltd.): 41.3 g, 2-ethylhexyl acid phosphate (JP-508T, manufactured by Johoku Chemical Industry Co., Ltd.): 0.01 g, And monoalcohol (Exenol 908, manufactured by AGC Corporation): 1.59 g was mixed, and a urethanization reaction was carried out at 110°C for 2 hours. The reaction solution was cooled to 80° C., and 27.8 g of 3,5-dimethylpyrazole was added as a blocking agent and stirred. After confirming that the characteristic absorption of the isocyanate group disappeared in the infrared spectrum, 76.4 g of dipropylene glycol monomethyl ether was added and further stirred for 30 minutes to obtain a blocked polyisocyanate composition BPa-1. The resulting blocked polyisocyanate composition had an effective NCO content of 4.8% by mass and had dispersibility in water.

[Example 2] Production of blocked polyisocyanate composition BPa-2 The inside of a four-necked flask equipped with a stirrer, a thermometer and a cooling tube was purged with nitrogen, and the polyisocyanate Pa-2 obtained in Synthesis Example 2 was obtained at 100%. 0 g, MPG-081: 53.9 g, JP-508T: 0.01 g, and EXENOL 908: 2.08 g were mixed and urethanized at 110° C. for 2 hours. Then, 13.5 g of PP400 was added as a bifunctional polyether polyol to the reaction liquid, and urethanization reaction was carried out at 110° C. for 2 hours. The reaction solution was cooled to 80° C., 35.7 g of 3,5-dimethylpyrazole was added as a blocking agent, and stirred. After confirming that the characteristic absorption of the isocyanate group disappeared in the infrared spectrum, 87.9 g of dipropylene glycol monomethyl ether was added, and the mixture was further stirred for 30 minutes to obtain a blocked polyisocyanate composition BPa-2. The resulting blocked polyisocyanate composition had an effective NCO content of 5.3% by mass and had dispersibility in water.

[Example 3] Production of blocked polyisocyanate composition BPa-3 The inside of a four-necked flask equipped with a stirrer, a thermometer and a cooling tube was replaced with nitrogen, and the polyisocyanate Pa-3 obtained in Synthesis Example 3: 100 0 g, MPG-081: 54.4 g, JP-508T: 0.01 g, and EXENOL 908: 2.10 g were mixed and urethanized at 110° C. for 2 hours. Then, 6.3 g of PP400 was added as a bifunctional polyether polyol to the reaction liquid, and urethanization reaction was carried out at 110° C. for 2 hours. The reaction solution was cooled to 80° C., 39.5 g of 3,5-dimethylpyrazole was added as a blocking agent, and stirred. After confirming that the characteristic absorption of the isocyanate group disappeared in the infrared spectrum, 86.7 g of dipropylene glycol monomethyl ether was added and further stirred for 30 minutes to obtain a blocked polyisocyanate composition BPa-3. The resulting blocked polyisocyanate composition had an effective NCO content of 6.0% by mass and had dispersibility in water.

[Example 4] Production of blocked polyisocyanate composition BPa-4 MPG-081: 89.8 g as methoxypolyethylene glycol, JP-508T: 0.02 g as 2-ethylhexyl acid phosphate, PP400: 6 as bifunctional polyether polyol .2 g, 34.2 g of 3,5-dimethylpyrazole as a blocking agent, and 99.5 g of dipropylene glycol monomethyl ether: 99.5 g of dipropylene glycol monomethyl ether. An isocyanate composition BPa-4 was prepared. The resulting blocked polyisocyanate composition had an effective NCO content of 4.5% by mass and had dispersibility in water.

[Example 5] Production of blocked polyisocyanate composition BPa-5 MPG-081: 71.8 g as methoxypolyethylene glycol, PP400: 3.1 g as bifunctional polyether polyol, 3,5-dimethylpyrazole as blocking agent 38.0 g. Block polyisocyanate composition BPa-5 was produced using the same method as described in Example 2, except that 2 g and dipropylene glycol monomethyl ether: 92.2 g were used. The resulting blocked polyisocyanate composition had an effective NCO content of 5.4% by mass and had dispersibility in water.

[Example 6] Production of blocked polyisocyanate composition BPa-6 Instead of PP400, OD-X-2722 (manufactured by DIC Corporation, number average molecular weight 2000) as a bifunctional polyester polyol: 31.1 g, 3 as a blocking agent , 5-dimethylpyrazole: 39.2 g, and dipropylene glycol monomethyl ether: 97.0 g were used, but using the same method as described in Example 2, block polyisocyanate composition BPa-6 manufactured. The resulting blocked polyisocyanate composition had an effective NCO content of 5.3% by mass and had dispersibility in water.

[Comparative Example 1] Production of blocked polyisocyanate composition BPb-1 MPG-081: 71.8 g as methoxypolyethylene glycol, JP-508T: 0.02 g as 2-ethylhexyl acid phosphate, PP400: 3 as bifunctional polyether polyol .1 g, 34.6 g of methyl ethyl ketoxime as a blocking agent, and 90.7 g of dipropylene glycol monomethyl ether: using the same method as described in Example 2, blocked polyisocyanate composition BPb -1 was produced. The resulting blocked polyisocyanate composition had an effective NCO content of 5.5% by mass and had dispersibility in water.

[Comparative Example 2] Production of blocked polyisocyanate composition BPb-2 Instead of PP400, 31.1 g of OD-X-2722 as a bifunctional polyester polyol, 35.5 g of methyl ethyl ketoxime as a blocking agent, and dipropylene glycol monomethyl Block polyisocyanate composition BPb-2 was produced using the same method as described in Example 2, except that 95.4 g of ether was used. The resulting blocked polyisocyanate composition had an effective NCO content of 5.4% by mass and had dispersibility in water.

[Comparative Example 3] Production of block polyisocyanate composition BPb-3 MPG-081: 35.7 g as methoxypolyethylene glycol, JP-508T as 2-ethylhexyl acid phosphate: 0.02 g, polycarbonate diol (Asahi Kasei Co., Ltd.) instead of PP400 Company product, trade name "Duranol T5652", number average molecular weight 2000) (hereinafter sometimes abbreviated as "T5652"): 103.3 g, methyl ethyl ketoxime 31.5 g as a blocking agent, and dipropylene glycol monomethyl ether A blocked polyisocyanate composition BPb-3 was produced using the same method as described in Example 2, except that 116.8 g of : was used. The resulting blocked polyisocyanate composition had an effective NCO content of 3.9% by mass and had dispersibility in water.

[Comparative Example 4] Production of blocked polyisocyanate composition BPb-4 MPG-081: 125.7 g as methoxypolyethylene glycol, JP-508T: 0.02 g as 2-ethylhexyl acid phosphate, PP400: 6 as bifunctional polyether polyol .2 g, 29.2 g of 3,5-dimethylpyrazole as a blocking agent, and 112.8 g of dipropylene glycol monomethyl ether: using a method similar to that described in Example 2, to obtain a block poly An isocyanate composition BPb-4 was prepared. The resulting blocked polyisocyanate composition had an effective NCO content of 3.4% by mass and had dispersibility in water.

[Comparative Example 5] Production of blocked polyisocyanate composition BPb-5 MPG-081: 7.2 g as methoxypolyethylene glycol, PP400: 6.2 g as bifunctional polyether polyol, 3,5-dimethylpyrazole as blocking agent 45.5 g. Block polyisocyanate composition BPb-5 was produced using the same method as described in Example 2, except that 7 g and dipropylene glycol monomethyl ether: 69.1 g were used. The resulting blocked polyisocyanate composition had an effective NCO content of 8.7% by mass and did not have dispersibility in water.

[Comparative Example 6] Production of blocked polyisocyanate composition BPb-6 42.2 g of 3,5-dimethylpyrazole as a blocking agent and 84 g of dipropylene glycol monomethyl ether without adding (C) polyol such as PP400. A blocked polyisocyanate composition BPb-6 was prepared using a method similar to that described in Example 2, except that 6 g was used. The resulting blocked polyisocyanate composition had an effective NCO content of 6.5% by mass and did not have dispersibility in water.

Using the blocked polyisocyanate compositions obtained in Examples and Comparative Examples, various physical properties were measured and evaluated according to the methods described above. The results are shown in Table 1 below.

From Table 1, it can be seen that the blocked polyisocyanate compositions BPa-1 to BPa-6 (Examples 1 to 6) have water dispersibility, excellent compatibility with the main agent, and curability and water resistance when formed into a coating film. The properties were good.
In addition, in the blocked polyisocyanate compositions BPa-2 and BPa-6 (Examples 2 and 6) having a content of (C) a structural unit derived from a polyol of 6.6% by mass or more (Examples 2 and 6), The curability was particularly excellent.

On the other hand, in the blocked polyisocyanate compositions BPb-1 to BPb-3 (Comparative Examples 1 to 3) using methyl ethyl ketoxime as a blocking agent other than (D) pyrazole-based compounds, curability and water resistance when formed into coating films Further, in the blocked polyisocyanate composition BPb-3 (Comparative Example 3) using T5652, which is a polyol other than (C) polyol, the compatibility with the main agent was also poor.
In addition, in the blocked polyisocyanate composition BPb-4 (Comparative Example 4) in which (A)/(B) is less than 50/50, the curability and water resistance when formed into a coating film were poor, and (A) The blocked polyisocyanate composition BPb-5 (Comparative Example 5) with /(B) exceeding 90/10 did not have water dispersibility.
Also, the blocked polyisocyanate composition BPb-6 (Comparative Example 6), which does not use any polyol such as (C) polyol, did not have water dispersibility.

The blocked polyisocyanate composition of the present embodiment includes, for example, curable compositions such as coating compositions, pressure-sensitive adhesive compositions, adhesive compositions, and casting compositions; various surface treatment agent compositions such as fiber treatment agents. various elastomer compositions; cross-linking agents for foam compositions; modifiers;

Claims (4)

(A) an isocyanate component containing at least one isocyanate compound selected from the group consisting of aliphatic diisocyanates and polyisocyanates derived from the aliphatic diisocyanates;
(B) an active hydrogen group-containing hydrophilic compound;
(C) at least one polyol selected from the group consisting of bifunctional polyester polyols and bifunctional polyether polyols;
(D) a pyrazole-based compound;
A blocked polyisocyanate composition obtained from, containing only the (D) pyrazole-based compound as a blocking agent, and
A blocked polyisocyanate composition that satisfies the following conditions (1) to (3).
(1) The mass ratio ((A)/(B)) of the structural unit derived from the isocyanate component (A) to the structural unit derived from the active hydrogen group-containing hydrophilic compound (B) is 50/50 or more and 90/10. is the following;
(2) The content of structural units derived from the (C) polyol is 1% by mass or more and 20% by mass or less with respect to the total mass of the blocked polyisocyanate composition;
(3) substantially no free isocyanate groups of the isocyanate component (A) 2. The blocked polyisocyanate composition according to claim 1, wherein the (C) polyol has a number average molecular weight of 300 or more and 3,000 or less. A water-based coating composition comprising the blocked polyisocyanate composition according to claim 1 or 2 and one or more main agents. A coating film obtained by curing the water-based coating composition according to claim 3.