JP7110029B2 - Hydrophilic polyisocyanate composition, curing agent composition and aqueous coating composition - Google Patents

Description

The present invention relates to hydrophilic polyisocyanate compositions, hardener compositions and waterborne coating compositions.

In recent years, from the viewpoint of environmental protection, there is a demand for a water-based two-liquid urethane coating composition which is used as a solvent-based paint and which is cross-linked at room temperature. However, the polyisocyanate used as the curing agent in the two-liquid urethane coating composition is difficult to disperse in water. Therefore, the development of polyisocyanates having hydrophilic groups is underway.

For example, in Patent Document 1, a hydrophilic polyisocyanate consisting of a polyisocyanate and a nonionic hydrophilic group containing an ethylene oxide repeating unit bound to the polyisocyanate, and an ionic surfactant containing substantially no water A polyisocyanate composition is disclosed comprising the agent. In addition, US Pat. No. 5,400,001 discloses water-dispersible polyisocyanate mixtures containing a specific range of ethylene oxide units.

JP-A-9-328654 JP-A-5-222150

The water-based two-liquid urethane coating composition is applied to furniture and building materials, woodwork for housing, sports floors, wooden floors for housing and school facilities, trains and construction machines, agricultural vehicles, and the like. For these uses, excellent flexibility, adhesion and conformability to substrates are required when used as coating films.
However, the polyisocyanate compositions having a hydrophilic group described in Patent Document 1 and Patent Document 2 may have reduced flexibility, adhesion and conformability to substrates when formed into coating films, and these demands are met. was difficult to meet. In addition, a polyisocyanate composition is desired in which the viscosity change is small when the hydrophilic polyisocyanate composition is stored.

The present invention has been made in view of the above circumstances, has a small change in viscosity during storage, is stably dispersed in water, and has flexibility, adhesion and substrate properties when formed into a coating film. Provided is a hydrophilic polyisocyanate composition having excellent conformability. A curing agent composition and a water-based coating composition comprising the hydrophilic polyisocyanate composition are provided.

That is, the present invention includes the following aspects.
The hydrophilic polyisocyanate composition according to the first aspect of the present invention is obtained by reacting a polyisocyanate obtained from one or more diisocyanates selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates with a hydrophilic compound. including the resulting hydrophilic polyisocyanate, satisfying the following (1) and (2),
The hydrophilic compound is a compound represented by the following general formula (I) .
(1) In the measurement spectrum of the hydrophilic polyisocyanate composition by gel permeation chromatography (GPC), there are UV absorption peaks of the diisocyanate trimer equivalent and the diisocyanate tetramer equivalent, The ratio ((Y)/(X)) of the UV absorption peak height (Y) of the diisocyanate tetramer equivalent to the UV absorption peak height (X) of the diisocyanate trimer equivalent is 0 .01 or more and 3 or less;
(2) Among the hydrophilic polyisocyanates, the hydrophilic polyisocyanate (A) obtained by reacting the polyisocyanate obtained from 3 molecules of the diisocyanate with 1 molecule of the hydrophilic compound, the poly obtained from 3 molecules of the diisocyanate The molar ratio ((B)/(A)) of the hydrophilic polyisocyanate (B) obtained by reacting the isocyanate with 2 or 3 molecules of the hydrophilic compound is 20/80 or more and 50/50 or less .

[In general formula (I), R ¹ is an alkylene group having 1 to 4 carbon atoms, and R ² is an alkyl group having 1 to 4 carbon atoms. n is 5 or more and 50 or less. ]

In the hydrophilic polyisocyanate composition according to the first aspect, the polyisocyanate (P) which is a polyisocyanate obtained from the three molecules of the diisocyanate and has not reacted with the hydrophilic compound, the hydrophilic polyisocyanate (A), And the ratio of the number of moles of the polyisocyanate (P) to the total number of moles of the hydrophilic polyisocyanate (B) ((P) / {(P) + (A) + (B)}) is 70% It may be 98% or less.
In general formula (I), R ¹ may be an ethylene group, and n may be 5 or more and 20 or less.
The polyisocyanate may contain one or more selected from the group consisting of isocyanurate groups and biuret groups.

A curing agent composition according to a second aspect of the present invention comprises the hydrophilic polyisocyanate composition according to the first aspect and an ionic surfactant, and the hydrophilic polyisocyanate composition and the ionic surfactant The ionic surfactant is contained in an amount of 0.1% by mass or more and 20% by mass or less with respect to the total solid content of.

A water-based coating composition according to a third aspect of the present invention comprises the hydrophilic polyisocyanate composition according to the first aspect or the curing agent composition according to the second aspect, water, and an active hydrogen compound.

According to the above aspect, the hydrophilic polyisocyanate composition has a small change in viscosity during storage, is stably dispersed in water, and has excellent flexibility, adhesion, and conformability to a substrate when formed into a coating film. can be provided. A curing agent composition and a water-based coating composition containing the hydrophilic polyisocyanate composition can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "this embodiment") for implementing this invention is demonstrated in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. Various modifications are possible for the present invention without departing from the gist thereof.

The amount of a particular functional group possessed by a composition or compound can be expressed herein as "molar ratio." That is, the dimension of the value obtained by dividing the number of specific functional groups possessed by the composition or compound by Avogadro's number is defined as moles. Thereby, the amount of the specified functional group is expressed as a "molar ratio" relative to the amount of other specified functional groups.
The specific functional group possessed by the composition refers to the specific functional group possessed by the compound contained in the composition.

<<Hydrophilic polyisocyanate composition>>
A hydrophilic polyisocyanate composition according to one embodiment of the present invention contains a hydrophilic polyisocyanate obtained by reacting a polyisocyanate with a hydrophilic compound.
The polyisocyanate is obtained from one or more diisocyanates selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.
Moreover, the hydrophilic polyisocyanate composition of the present embodiment satisfies the following (1) and (2).
(1) In the measurement spectrum of the hydrophilic polyisocyanate composition by GPC, there are UV absorption peaks of the diisocyanate trimer equivalent and the diisocyanate tetramer equivalent, and the diisocyanate trimer equivalent UV absorption peak. The ratio of the height (Y) of the UV absorption peak of the diisocyanate tetramer equivalent to the height (X) of ((Y)/(X)) is 0.01 or more and 3 or less;
(2) Among the hydrophilic polyisocyanates, the polyisocyanate obtained from 3 molecules of diisocyanate and hydrophilicity with respect to the hydrophilic polyisocyanate (A) obtained by reacting the polyisocyanate obtained from 3 molecules of diisocyanate with 1 molecule of a hydrophilic compound. The molar ratio ((B)/(A)) of hydrophilic polyisocyanate (B) obtained by reaction with compound 2 or 3 molecules is 20/80 or more and 50/50 or less.

<Constituent>
The constituent components of the hydrophilic polyisocyanate composition of the present embodiment are described in detail below.

[Hydrophilic polyisocyanate]
The hydrophilic polyisocyanate contained in the hydrophilic polyisocyanate composition of the present embodiment is a reactant obtained by reacting the polyisocyanate with a hydrophilic compound. That is, the hydrophilic polyisocyanate is a reactant to which a hydrophilic group derived from a hydrophilic compound is added by reacting a hydrophilic compound with an isocyanate group.

○ Polyisocyanate As used herein, the term “polyisocyanate” means a reactant in which a plurality of compounds having one or more isocyanate groups (—NCO) are bonded. One molecule of a compound having one or more isocyanate groups (--NCO) derived from polyisocyanate may be referred to as a monomer.

(Constituent component of polyisocyanate)
The polyisocyanate from which the hydrophilic polyisocyanate of the present embodiment is derived is a reactant obtained by reacting one or more diisocyanates selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.
The terms "aliphatic diisocyanate" and "alicyclic diisocyanate" used herein mean compounds that do not contain an aromatic ring such as a benzene ring in the structure of the diisocyanate.

The aliphatic diisocyanate is not particularly limited, but preferably has 4 to 30 carbon atoms. Specific examples of aliphatic diisocyanates include tetramethylene-1,4-diisocyanate, 2-methylpentane-1,5-diisocyanate (hereinafter sometimes referred to as "MPDI"), hexamethylene diisocyanate (hereinafter, " HDI”), 2,2,4-trimethyl-hexamethylene-1,6-diisocyanate, lysine diisocyanate (hereinafter sometimes referred to as “LDI”), and the like.
The alicyclic diisocyanate is not particularly limited, but preferably has 8 or more and 30 or less carbon atoms. Specific examples of the alicyclic diisocyanate include isophorone diisocyanate (hereinafter sometimes referred to as "IPDI"), hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and the like.
These aliphatic diisocyanates and alicyclic diisocyanates may be used singly or in combination of two or more.

Among them, the diisocyanate is preferably HDI, IPDI, hydrogenated xylylene diisocyanate or hydrogenated diphenylmethane diisocyanate, and more preferably HDI, because of its industrial availability. Since the polyisocyanate from which the hydrophilic polyisocyanate of the present embodiment is derived is obtained by reacting HDI, the appearance and weather resistance tend to be more excellent when the hydrophilic polyisocyanate composition is used as a coating film. be.

(Functional group of polyisocyanate)
The polyisocyanate from which the hydrophilic polyisocyanate of the present embodiment is derived preferably contains a reactant obtained by reacting two or more molecules of diisocyanate, and includes a reactant obtained by reacting three or more molecules of diisocyanate. is more preferable. As a result, the flexibility, adhesion and conformability to the substrate tend to be more excellent when formed into a coating film.

Polyisocyanates containing reactants obtained by reacting two or more diisocyanate molecules include isocyanurate groups, biuret groups, uretdione groups, oxadiazinetrione groups, iminooxadiazinedione groups, allophanate groups, urethane groups and urea groups. It can contain one or more selected from the group consisting of

Among them, the polyisocyanate from which the hydrophilic polyisocyanate of the present embodiment is derived preferably contains an isocyanurate group. As a result, when the polyisocyanate composition is used as a coating film, the curability, hardness and weather resistance tend to be more excellent.
Moreover, the polyisocyanate from which the hydrophilic polyisocyanate of the present embodiment is derived preferably contains a biuret group. As a result, there is a tendency that the water dispersion stability, the flexibility, the adhesion and the conformability to the substrate when formed into a coating film are more excellent.

The method for producing a polyisocyanate containing an isocyanurate group is not particularly limited. For example, a reaction is performed to convert a diisocyanate into an isocyanurate with a catalyst or the like, and the reaction is stopped when a predetermined conversion rate is reached, Examples include a method for removing unreacted diisocyanate.

As a method for removing unreacted diisocyanate, it is preferable to use a thin-film distillation apparatus because it can suppress coloring of the resulting polyisocyanate. Furthermore, in order to reduce the viscosity change during storage, thin film distillation is performed, and then the treatment liquid is stirred and UV is intermittently irradiated under vacuum conditions (0.3 to 1.0 Torr). , Heat treatment is performed at about 130 ° C. to 160 ° C. for about 15 minutes to 90 minutes, and UV (365 nm) irradiation for about 5 minutes and no irradiation for about 10 minutes are set as 1 set, 1 set or more 6 sets It is preferable to perform thin-film distillation after performing the following steps.

The catalyst used in the above isocyanurate-forming reaction is not particularly limited, but one exhibiting basicity is preferred. Specific examples of the catalyst include those shown below.
(1) Hydroxides of tetraalkylammonium such as tetramethylammonium and tetraethylammonium, and organic weak acid salts thereof such as acetic acid and capric acid.
(2) Hydroxylalkylammonium hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium and triethylhydroxyethylammonium, and their organic weak acid salts such as acetic acid and capric acid.
(3) Alkali metal salts such as tin, zinc and lead of alkylcarboxylic acids such as acetic acid, caproic acid, octylic acid and myristic acid.
(4) metal alcoholates such as sodium and potassium;
(5) Aminosilyl group-containing compounds such as hexamethyldisilazane.
(6) Mannich bases.
(7) Mixtures of tertiary amines and epoxy compounds.
(8) Phosphorus compounds such as tributylphosphine.

The amount of the catalyst used is preferably 10 ppm or more and 11000 ppm or less with respect to the total mass of the raw material diisocyanate.
In addition, in order to terminate the isocyanurate reaction, the catalyst may be deactivated by addition of an acidic substance such as phosphoric acid or acid phosphate for neutralizing the catalyst, thermal decomposition, chemical decomposition, or the like.

Although the reaction temperature for the isocyanurate-forming reaction is not particularly limited, it is preferably 50° C. or higher and 200° C. or lower, and more preferably 50° C. or higher and 150° C. or lower. When the reaction temperature is equal to or higher than the above lower limit, the reaction tends to proceed more easily. On the other hand, when the reaction temperature is equal to or lower than the above upper limit, side reactions that cause coloration tend to be more suppressed.

After completion of the isocyanurate-forming reaction, unreacted diisocyanate monomers are preferably removed by thin film evaporator, extraction, or the like.
Further, when the polyisocyanate from which the hydrophilic polyisocyanate of the present embodiment is derived contains an unreacted diisocyanate, the unreacted diisocyanate may contain 3.0% by mass or less with respect to the total mass of the hydrophilic polyisocyanate. It is preferably contained in an amount of 1.0% by mass or less, more preferably 0.5% by mass or less. Curability tends to be more excellent when the concentration of the residual unreacted diisocyanate monomer is equal to or less than the above upper limit.

A method for producing a polyisocyanate containing a biuret group is not particularly limited, but the following method is preferably exemplified. Specifically, first, a reaction between a diisocyanate monomer and a biuretizing agent disclosed in Japanese Patent Publication No. 41496/1987 (reference document 1) is carried out under uniform stirring. Subsequently, a polyisocyanate containing biuret groups is obtained by continuous production in which the reaction product is further introduced into a pipe reactor and the reaction proceeds in the pipe reactor under the extrusion flow.

(Physical properties of polyisocyanate)
The physical properties of the polyisocyanate from which the hydrophilic polyisocyanate of the present embodiment is derived are described in detail below.

Viscosity The viscosity at 25°C of the polyisocyanate from which the hydrophilic polyisocyanate of the present embodiment is derived is not particularly limited, but is preferably 100 mPa s or more and 30000 mPa s or less, and 500 mPa s or more and 10000 mPa s or less. is more preferable.
The viscosity at 25° C. can be measured by the method described in Examples below.

· Isocyanate group content The isocyanate group content of the polyisocyanate from which the hydrophilic polyisocyanate of the present embodiment is derived is not particularly limited, but is 5.0% by mass or more and 25% by mass or less with respect to the total mass of the polyisocyanate. , more preferably 10% by mass or more and 24% by mass or less, and even more preferably 15% by mass or more and 24% by mass or less.
The isocyanate group content can be measured by the method described in Examples below.

- Content of polyisocyanate obtained from 3 molecules of diisocyanate The polyisocyanate derived from the hydrophilic polyisocyanate of the present embodiment is not particularly limited, but the polyisocyanate obtained from 3 molecules of diisocyanate is used as a coating film. From the viewpoint of properties, adhesion and conformability to the substrate, it preferably contains 20% by mass or more and 75% by mass or less, more preferably 30% by mass or more and 70% by mass or less, relative to the total mass of the polyisocyanate. .
The content of polyisocyanate obtained from 3 molecules of diisocyanate can be measured by the method described in Examples below.

○Hydrophilic compound The hydrophilic polyisocyanate of the present embodiment has a structural unit derived from a hydrophilic compound. This is because the hydrophilic compound is a compound having a hydrophilic group. That is, the hydrophilic group is a functional group possessed (added) to the hydrophilic polyisocyanate obtained by reacting the hydrophilic compound with the polyisocyanate. By having (adding) a hydrophilic group to the hydrophilic polyisocyanate, the hydrophilic polyisocyanate composition of the present embodiment can obtain stable water dispersibility.

Examples of hydrophilic groups include, but are not limited to, nonionic hydrophilic groups, cationic hydrophilic groups, and anionic hydrophilic groups.
Among them, nonionic hydrophilic groups are preferable as the hydrophilic group from the viewpoint of availability and resistance to electrical interaction with the formulation.

(Hydrophilic compound having nonionic hydrophilic group)
The hydrophilic compound having a nonionic hydrophilic group is not particularly limited, but examples thereof include monoalcohols such as methanol, ethanol and butanol; compounds obtained by adding alkylene oxide to hydroxyl groups of alcohols such as alkylene glycol and dialkylene glycol; Compounds represented by formula (I) (hereinafter sometimes referred to as "compound (I)") and the like. These hydrophilic compounds having nonionic hydrophilic groups also have active hydrogen groups that react with isocyanate groups.

[In general formula (I), R ¹ is an alkylene group having 1 to 4 carbon atoms, and R ² is an alkyl group having 1 to 4 carbon atoms. n is 5 or more and 50 or less. ]

Among them, the hydrophilic compound having a nonionic hydrophilic group is preferably a monoalcohol or compound (I), more preferably compound (I), because it can improve the water dispersibility of the hydrophilic polyisocyanate composition with a small amount. .

・Compound (I)
Compound (I) is a polyalkylene glycol monoalkyl ether. Compound (I) is described in detail below.

In general formula (I), R ¹ is an alkylene group having 1 to 4 carbon atoms. The alkylene group may be linear, branched, or cyclic (aliphatic cyclic group). The number of carbon atoms in the alkylene group is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, and even more preferably 1 or more and 2 or less.
Specific examples of the alkylene group include methylene group, ethylene group, trimethylene group, dimethylmethylene group, cyclotrimethylene group, tetramethylene group, dimethylethylene group, cyclotetramethylene group and the like.
Among them, the alkylene group is preferably a methylene group or an ethylene group, and more preferably an ethylene group.

In general formula (I), R ² is an alkyl group having 1 to 4 carbon atoms. The alkyl group may be linear, branched, or cyclic (aliphatic cyclic group). The number of carbon atoms in the alkyl group is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, and even more preferably 1 or more and 2 or less.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, cyclobutyl group and the like. .
Among them, the alkyl group is preferably a methyl group or an ethyl group, more preferably a methyl group.

In general formula (I), n is the number of repeating alkyleneoxy groups ( ^--R.sub.1 --O--). n is preferably 5 or more and 50 or less, more preferably 5 or more and 30 or less, because it is possible to suppress the water dispersibility of the hydrophilic polyisocyanate composition and the precipitation of the hydrophilic polyisocyanate composition during low-temperature storage. 20 or less is more preferable.

Preferred compounds (I) include, for example, compounds represented by the following formula (I-1) (ie, polyethylene glycol monoethers).
HO(CH ₂ CH ₂ O) _n1 CH ₃ (I-1)

[In the formula (I-1), n1 is 5 or more and 20 or less. ]

(Hydrophilic compound having a cationic hydrophilic group)
The hydrophilic compound having a cationic hydrophilic group is not particularly limited, but examples thereof include compounds having both a cationic group and an active hydrogen group. Also, a compound having an active hydrogen group such as a glycidyl group and a compound having a cationic hydrophilic group such as sulfide or phosphine may be combined as a hydrophilic compound. In this case, a compound having an isocyanate group and a compound having an active hydrogen group are reacted in advance to add a functional group such as a glycidyl group. Then, after that, compounds such as sulfides and phosphines are reacted. Among them, as the hydrophilic compound having a cationic hydrophilic group, a compound having both a cationic group and an active hydrogen group is preferable from the viewpoint of ease of production.

Examples of compounds having both a cationic group and an active hydrogen group include, but are not particularly limited to, dimethylethanolamine, diethylethanolamine, diethanolamine, methyldiethanolamine, and the like. Also, the tertiary amino group added using these compounds can be quaternized with, for example, dimethyl sulfate, diethyl sulfate, or the like.

The reaction between the hydrophilic compound having a cationic hydrophilic group and the polyisocyanate can be carried out in the presence of a solvent. The solvent is not particularly limited, but preferably does not contain an active hydrogen group. Specific examples of solvents include ethyl acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol dimethyl ether.

The cationic hydrophilic group added to the polyisocyanate is preferably neutralized with a compound having an anionic group. Examples of the anion group include, but are not particularly limited to, a carboxy group, a sulfonic acid group, a phosphoric acid group, a halogen group, and a sulfate group.
Examples of compounds having a carboxy group include, but are not particularly limited to, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, and the like.
The compound having a sulfonic acid group is not particularly limited, but specifically includes ethanesulfonic acid and the like.
Examples of the compound having a phosphoric acid group include, but are not particularly limited to, phosphoric acid, acidic phosphoric acid esters, and the like.
Examples of the compound having a halogen group include, but are not particularly limited to, hydrochloric acid.
The compound having a sulfate group is not particularly limited, and examples thereof include sulfuric acid.
Among them, the compound having an anion group is preferably a compound having a carboxy group, and more preferably acetic acid, propionic acid or butyric acid.

(Hydrophilic compound having anionic hydrophilic group)
Examples of the anionic hydrophilic group include, but are not particularly limited to, a carboxy group, a sulfonic acid group, a phosphoric acid group, a halogen group, a sulfate group, and the like.
Examples of the hydrophilic compound having an anionic hydrophilic group include, but are not particularly limited to, compounds having both an anionic group and an active hydrogen group. Specific examples of hydrophilic compounds having an anionic hydrophilic group include monohydroxycarboxylic acids such as 1-hydroxyacetic acid, 3-hydroxypropanoic acid, 12-hydroxy-9-octadecanoic acid, hydroxypivalic acid, and lactic acid; Compounds having a carboxyl group of polyhydroxycarboxylic acid such as dimethylolacetic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, and dimethylolpropionic acid as an anion group. Also, the hydrophilic compound having an anionic hydrophilic group may be a compound having both a sulfonic acid group and an active hydrogen. Specific examples of compounds having both a sulfonic acid group and an active hydrogen include isethionic acid and the like.
Among them, hydroxypivalic acid or dimethylolpropionic acid is preferable as the hydrophilic compound having an anionic hydrophilic group.

The anionic hydrophilic group added to the polyisocyanate is preferably neutralized with an amine compound, which is a basic substance.
Examples of the amine-based compound include, but are not particularly limited to, ammonia, water-soluble amino compounds, and the like.
Examples of water-soluble amino compounds include, but are not limited to, monoethanolamine, ethylamine, dimethylamine, diethylamine, triethylamine, propylamine, dipropylamine, isopropylamine, diisopropylamine, triethanolamine, butylamine, dibutylamine, 2 - ethylhexylamine, ethylenediamine, propylenediamine, methylethanolamine, dimethylethanolamine, diethylethanolamine, morpholine and the like. In addition, tertiary amines such as triethylamine and dimethylethanolamine may also be used.

○ Diisocyanate compound having a hydroxy group The hydrophilic polyisocyanate of the present embodiment is obtained by reacting the above diisocyanate with an alcohol having a valence of 1 or more and 6 or less, in addition to the above-mentioned polyisocyanate and hydrophilic compound. It may contain a reactant (hereinafter sometimes referred to as "a diisocyanate compound having a hydroxy group").
Examples of alcohols having a valence of 1 to 6 include non-polymerized alcohols and polymerized alcohols. A non-polymerized alcohol is an alcohol having no polymerizable group, and a polymerized alcohol is an alcohol obtained by polymerizing a monomer having a polymerizable group and a hydroxy group.

(non-polymerized alcohol)
Examples of non-polymerized alcohols include, but are not particularly limited to, monoalcohols, diols, triols, tetraols, and the like.

Monoalcohols Monoalcohols are not particularly limited, but examples include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, n-pentanol, n-hexanol, n-octanol, n-nonanol, 2-ethylbutanol, 2,2-dimethylhexanol, 2-ethylhexanol, cyclohexanol, methylcyclohexanol, ethylcyclohexanol and the like.

Diols Diols are not particularly limited, but examples include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol, 1,3-propanediol, 1, and 1. ,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,2-propanediol, 1,5-pentanediol, 2-methyl-2 ,3-butanediol, 1,6-hexanediol, 1,2-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 2,3-dimethyl-2,3-butanediol , 2-ethyl-hexanediol, 1,2-octanediol, 1,2-decanediol, 2,2,4-trimethylpentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2 -diethyl-1,3-propanediol and the like.

- Triols Triols are not particularly limited, but examples thereof include glycerin and trimethylolpropane.

- Tetraols The tetraols are not particularly limited, and examples thereof include pentaerythritol.

(Polymerized alcohol)
Polymerized alcohols are not particularly limited, but examples include polyester polyols, polyether polyols, acrylic polyols, polyolefin polyols, and the like.

- Polyester polyol As the polyester polyol, for example, polyester polyol resins obtained by a condensation reaction of a dicarboxylic acid alone or a mixture of two or more kinds and a polyhydric alcohol alone or a mixture of two or more kinds; Examples thereof include polycaprolactones obtained by ring-opening polymerization of ε-caprolactone.

Examples of the dicarboxylic acid include carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and 1,4-cyclohexanedicarboxylic acid.
Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, trimethylolpropane, glycerin, and pentaerythritol. , 2-methylolpropanediol, ethoxylated trimethylolpropane, and the like.

· Polyether polyol The polyether polyol is not particularly limited, but examples thereof include those obtained by using any of the following methods (1) to (3).
(1) Polyether polyols or polytetramethylene obtained by the reaction of at least one of the group consisting of random addition and block addition of alkylene oxide alone or in mixture to polyhydric hydroxy compound alone or in mixture using a catalyst. glycols.
(2) Polyether polyols obtained by reacting an alkylene oxide with a polyamine compound (3) A so-called polymer obtained by polymerizing acrylamide or the like using the polyether polyols obtained in (1) or (2) as a medium polyols.

Examples of the catalyst include hydroxides of lithium, sodium, potassium and the like; strongly basic catalysts such as alcoholates and alkylamines; and double metal cyanide complexes such as metal porphyrins and zinc hexacyanocobaltate complexes.
Examples of polyvalent hydroxy compounds include diglycerin, ditrimethylolpropane; sugars such as pentaerythritol, dipentaerythritol, erythritol, D-threitol, L-arabinitol, ribitol, xylitol, sorbitol, mannitol, galactitol and rhamnitol. Alcohol compounds; monosaccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, and ribodeose; disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, and melibiose; raffinose , gentianose, and melezitose; and tetrasaccharides such as stachyose.
Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide.
Examples of the polyamine compound include ethylenediamine and ethanolamines.

・Acrylic polyol The acrylic polyol is not particularly limited, but for example, a polymerizable monomer having a hydroxy group is polymerized, or an ethylenically unsaturated bond-containing monomer having a hydroxy group is used alone or in a mixture. It can be obtained by copolymerizing a polymerizable monomer with another ethylenically unsaturated bond-containing monomer or a mixture thereof.

Examples of ethylenically unsaturated bond-containing monomers having a hydroxy group include, but are not limited to, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and methacrylic acid. hydroxybutyl and the like. These may be used alone or in combination of two or more.
Among them, hydroxyethyl acrylate or hydroxyethyl methacrylate is preferable as the ethylenically unsaturated bond-containing monomer having a hydroxy group.

Other ethylenically unsaturated bond-containing monomers copolymerizable with the polymerizable monomer include, for example, the following. These may be used alone or in combination of two or more.
(i) acrylic acid esters such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate and 2-ethylhexyl acrylate;
(ii) methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate, and glycidyl methacrylate .
(iii) unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and itaconic acid;
(iv) unsaturated amides such as acrylamide, methacrylamide, N,N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, maleic acid amide and maleimide;
(v) Vinyl monomers such as glycidyl methacrylate, styrene, vinyl toluene, vinyl acetate, acrylonitrile, and dibutyl fumarate.
(vi) vinyl-based monomers having a hydrolyzable silyl group, such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane;

· Polyolefin polyol The polyolefin polyol is not particularly limited, and examples thereof include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.

<Method for producing hydrophilic polyisocyanate composition>
The method for producing a hydrophilic polyisocyanate composition of the present embodiment includes a step of mixing and reacting the polyisocyanate and the hydrophilic compound to obtain a hydrophilic polyisocyanate composition containing the hydrophilic polyisocyanate (reaction step ).
The steps of the method for producing the hydrophilic polyisocyanate composition of the present embodiment are described in detail below.

[Reaction step]
In the reaction step, the content of the hydrophilic compound relative to the total solid content of the resulting hydrophilic polyisocyanate composition is preferably 2.0% by mass or more and 50% by mass or less, more preferably 5% by mass. 0% by mass or more and 30% by mass or less, more preferably 5.0% by mass or more and 20% by mass or less.
By reacting so that the content of the hydrophilic compound with respect to the total solid content of the hydrophilic polyisocyanate composition obtained is the above lower limit or more, the water dispersibility of the hydrophilic polyisocyanate composition of the present embodiment and Water dispersion stability can be improved.
On the other hand, by reacting so that the content of the hydrophilic compound with respect to the total solid content of the hydrophilic polyisocyanate composition obtained is the above upper limit or less, the flexibility, adhesion and base Followability to the material can be improved.

In the reaction step, the reaction temperature and reaction time are appropriately determined according to the progress of the reaction.
The reaction temperature is preferably 0° C. or higher and 150° C. or lower, and the reaction time is preferably 0.5 hours or longer and 48 hours or shorter.

In addition, in the reaction step, a known catalyst may be used as the case may be. Examples of catalysts include, but are not limited to, tin octoate, tin 2-ethyl-1-hexanoate, tin ethylcaproate, tin laurate, tin palmitate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate. , dibutyltin dimalate, dibutyltin dilaurate, dioctyltin diacetate, dioctyltin dilaurate; zinc chloride, zinc octanoate, zinc 2-ethyl-1-hexanoate, zinc 2-ethylcaproate, zinc stearate, organic zinc compounds such as zinc naphthenate and zinc acetylacetonate; organic titanium compounds; organic zirconium compounds; tertiary amines such as triethylamine, tributylamine, N,N-diisopropylethylamine and N,N-dimethylethanolamine; Examples include diamines such as tetramethylethylenediamine and 1,4-diazabicyclo[2.2.2]octane. These may be used singly or in combination.

Further, in the reaction step, among the hydrophilic polyisocyanates, the hydrophilic polyisocyanate (A) obtained by reacting the polyisocyanate obtained from 3 molecules of the diisocyanate with 1 molecule of the hydrophilic compound, the polyisocyanate obtained from 3 molecules of the diisocyanate In order to adjust the molar ratio ((B)/(A)) of the hydrophilic polyisocyanate (B) obtained by reacting the isocyanate with 2 or 3 molecules of the hydrophilic compound, the polyisocyanate is added in two steps. method. That is, there is a method of completely reacting a part of the polyisocyanate and the entire amount of the hydrophilic compound, and then adding the remaining polyisocyanate. Higher molar concentrations of the hydrophilic polyisocyanate obtained by this method or by reaction with 2 or 3 molecules of a hydrophilic compound can be achieved.

<Physical properties>
Next, the physical properties of the hydrophilic polyisocyanate composition of this embodiment will be described in detail below.

[(Y)/(X)]
The hydrophilic polyisocyanate composition of the present embodiment comprises a diisocyanate trimer equivalent and a diisocyanate tetramer equivalent. The diisocyanate trimer equivalent and the diisocyanate tetramer equivalent can be measured as compounds having UV absorption in measurement by GPC.

The amount of the diisocyanate trimer equivalent and the diisocyanate tetramer equivalent present is the height of the UV absorption peak of the diisocyanate trimer (X), and the UV absorption peak of the diisocyanate tetramer equivalent. When the height is (Y), it is represented by the ratio of (Y) to (X) ((Y)/(X)).
(Y)/(X) is 0.01 or more and 3.0 or less, preferably 0.01 or more and 2.0 or less, more preferably 0.01 or more and 0.25 or less, and 0.01 or more and 0.05 or less is more preferred. By making (Y)/(X) equal to or less than the above upper limit value, the viscosity stability of the hydrophilic polyisocyanate composition, the solvent dilutability of the water-based coating composition, and the transparency of the coating film are more excellent. In addition, by setting (Y) / (X) to the above lower limit or more, the chromaticity stability of the hydrophilic polyisocyanate composition during storage under high temperature conditions, the curability of the water-based coating composition and the heat resistance of the coating film Better yellowing.

The ratio of the UV absorption peak height (Y) of the diisocyanate tetramer equivalent to the UV absorption peak height (X) of the diisocyanate trimer equivalent in the polyisocyanate composition of the present embodiment ((Y) /(X)) can be measured using the method described in Examples below.

[(B)/(A)]
The hydrophilic polyisocyanate composition of the present embodiment includes a hydrophilic polyisocyanate (A) obtained by reacting a polyisocyanate obtained from 3 molecules of diisocyanate with 1 molecule of a hydrophilic compound, and a polyisocyanate obtained from 3 molecules of diisocyanate. and a hydrophilic polyisocyanate (B) obtained by reaction with 2 or 3 molecules of a hydrophilic compound.
In the hydrophilic polyisocyanate composition of the present embodiment, the molar ratio of (B) to (A) ((B)/(A)) is preferably 20/80 or more and 50/50 or less, and 20/80 It is more preferably 42/58 or less, and further preferably 22/78 or more and 30/70 or less.
When (B)/(A) is within the above range, the flexibility, adhesion and conformability to the substrate can be further improved when formed into a coating film.
(B)/(A) can be calculated using the method described in Examples below. The method for controlling (B)/(A) within the above range is not particularly limited, but includes, for example, the method described in the above-mentioned "Method for producing hydrophilic polyisocyanate composition".

[(P)/{(P)+(A)+(B)}]
In the hydrophilic polyisocyanate composition of the present embodiment, a polyisocyanate obtained from three diisocyanate molecules and not reacting with a hydrophilic compound (P), a hydrophilic polyisocyanate (A), and a hydrophilic poly The ratio of the number of moles of the polyisocyanate (P) to the total number of moles of the isocyanate (B) ((P)/{(P)+(A)+(B)}) is not particularly limited, but is 70 %. It is preferably 98 % or less, more preferably 75 % or more and 97 % or less, and even more preferably 80 % or more and 96 % or less.
(P) / {(P) + (A) + (B)} is in the above range, so that water dispersibility and curability, appearance, hardness, water resistance and chemical resistance when used as a coating film properties can be improved.
(P)/{(P)+(A)+(B)} can be calculated using the method described in Examples below.
In addition, the method for controlling (P) / {(P) + (A) + (B)} within the above range is not particularly limited, but for example, a method obtained by reacting a polyisocyanate with a hydrophilic compound, and a method of reacting a hydrophilic compound with a polyisocyanate and then adding the polyisocyanate.

[Content of hydrophilic group derived from hydrophilic compound relative to total solid content]
In the hydrophilic polyisocyanate composition of the present embodiment, the blending amount of the hydrophilic compound with respect to the total solid content of the polyisocyanate and the hydrophilic compound is preferably 2.0% by mass or more and 50% by mass or less, and 5.0% by mass. It is more preferably 5.0% by mass or more and 20% by mass or less, more preferably 5.0% by mass or more and 20% by mass or less.
Further, the content of hydrophilic groups derived from hydrophilic compounds with respect to the total solid content of the hydrophilic polyisocyanate composition of the present embodiment is preferably 2.0% by mass or more and 50% by mass or less, and 5.0% by mass. It is more preferably 5.0% by mass or more and 20% by mass or less, more preferably 5.0% by mass or more and 20% by mass or less.
Since the content of hydrophilic groups derived from the hydrophilic compound with respect to the total solid content of the hydrophilic polyisocyanate composition is at least the above lower limit, the water dispersibility and water dispersion of the hydrophilic polyisocyanate composition of the present embodiment Better stability.
On the other hand, when the content of hydrophilic groups derived from the hydrophilic compound with respect to the total solid content of the hydrophilic polyisocyanate composition is equal to or less than the above upper limit, the hardness and water resistance of the coating film can be improved. .
The blending amount of the hydrophilic compound with respect to the total solid content of the polyisocyanate and the hydrophilic compound is calculated by multiplying the value obtained by dividing the mass of the hydrophilic compound by the total solid content of the hydrophilic polyisocyanate composition by 100. can do. In addition, since all of the formulated hydrophilic compounds react with polyisocyanate, the content of hydrophilic groups derived from hydrophilic compounds with respect to the total solid content of the hydrophilic polyisocyanate composition is the total solid content of polyisocyanate and hydrophilic compounds. It is obtained by calculating the blending amount of the hydrophilic compound with respect to the amount.

[viscosity]
The viscosity at 25° C. of the hydrophilic polyisocyanate composition of the present embodiment is usually 50 mPa·s or more and 20000 mPa·s or less when the hydrophilic polyisocyanate composition consists substantially only of a solid content at 25° C. , 300 mPa·s or more and 10000 mPa·s or less.
When the viscosity at 25° C. is at least the above lower limit, the curability of the coating film can be improved, while when it is at most the above upper limit, the water dispersibility and appearance of the coating film are improved. can be made better.
In addition, "consisting substantially only of solid content" here means that it consists only of solid content, or contains only a very small amount of components other than solid content (liquid component and volatile component, etc.) below the detection limit. means
The viscosity at 25° C. of the hydrophilic polyisocyanate composition can be measured using the method described in Examples below.

A method for controlling the viscosity at 25° C. within the above range is not particularly limited, but examples thereof include a method of adjusting the compounding ratio of the polyisocyanate and the hydrophilic compound.

[Isocyanate group content]
The isocyanate group content in the hydrophilic polyisocyanate composition of the present embodiment is usually 3.0% by mass or more and 25% by mass or less when the hydrophilic polyisocyanate composition substantially consists only of solids. , preferably 7.0% by mass or more and 20% by mass or less, more preferably 13% by mass or more and 20% by mass or less.
When the isocyanate group content is within the above range, the flexibility, adhesion, and conformability to the substrate can be further improved when formed into a coating film.
The term "isocyanate group" as used herein refers to a combination of the isocyanate group possessed by the unreacted polyisocyanate and the isocyanate group possessed by the hydrophilic polyisocyanate.
The isocyanate group content of the hydrophilic polyisocyanate composition can be calculated using the method described in Examples below.

A method for controlling the isocyanate group content within the above range is not particularly limited, but an example thereof includes a method of adjusting the compounding ratio of the polyisocyanate and the hydrophilic compound.

[Number average molecular weight]
The number average molecular weight of the hydrophilic polyisocyanate composition of the present embodiment is preferably 300 or more from the viewpoint of curability when used as a coating film, and preferably 10000 or less from the viewpoint of water dispersibility.
The number average molecular weight of the hydrophilic polyisocyanate composition can be measured using the method described in the examples below.

[Average number of isocyanate functional groups]
The average number of isocyanate functional groups in the hydrophilic polyisocyanate composition of the present embodiment (hereinafter sometimes referred to as "average number of isocyanate functional groups") is the flexibility, adhesion and substrate adhesion when used as a coating film. From the viewpoint of followability, it is preferably 2.0 or more, and from the viewpoint of water dispersion stability, it is preferably 20.0 or less.
The average number of isocyanate functional groups of the hydrophilic polyisocyanate composition can be calculated using the method described in the examples below.

<<Curing agent composition>>
A curing agent composition according to one embodiment of the present invention comprises the hydrophilic polyisocyanate composition described above and an ionic surfactant. In addition, the curing agent composition of the present embodiment contains 0.1% by mass or more and 20% by mass or less of the ionic surfactant with respect to the total solid content of the hydrophilic polyisocyanate composition and the ionic surfactant.

<Constituent>
The constituent components of the curing agent composition of this embodiment will be described in detail below.

[Ionic surfactant]
Preferably, the ionic surfactant contained in the curing agent composition of the present embodiment does not substantially contain water.
Here, "substantially free of water" means that it does not contain water at all, or that the water contained in the ionic surfactant reacts with the isocyanate group to prevent foaming, cloudiness, and viscosity increase. It means that it contains only a very small amount of water. As a guideline, the water content should be 1% by mass or less with respect to the total mass of the ionic surfactant.

Examples of ionic surfactants include anionic surfactants, cationic surfactants, and amphoteric surfactants. The method of neutralization of the hydrophilic polyisocyanate composition determines whether anionic or cationic surfactants are preferred. That is, when the hydrophilic polyisocyanate composition is neutralized with a base, it is preferable to use an anionic surfactant, while when it is neutralized with an acid, it is preferable to use a cationic surfactant. If the hydrophilic polyisocyanate composition is not neutralized, either an anionic surfactant or a cationic surfactant may be used, or an amphoteric surfactant may be used.

Suitable anionic surfactants are those of the carboxylate, sulfate, sulfonate or phosphate type.
Specific examples of anionic surfactants include (C1-C20 alkyl) ammonium benzenesulfonate, sodium (C1-C20 alkyl) benzene sulfonate, sodium (C1-C20 alkyl) disulfate, and sodium alkyldiphenyl ether disulfonate. , sodium di(C1-C20 alkyl) sulfosuccinate, sodium polyoxyethylene C6-C30 aryl ether sulfonate, ammonium polyoxyethylene C6-C30 aryl ether sulfonate, and the like, provided that they are industrially available. It can be used without any inconvenience and is not limited to the above.
Among them, the anionic surfactant is preferably ammonium (C1-C20 alkyl)benzenesulfonate, sodium (C1-C20 alkyl)benzenesulfonate or sodium di(C1-C20 alkyl)sulfosuccinate.

Quaternary ammonium salts, pyridinium salts or imidazolinium salts are suitable as cationic surfactants.
Specific examples of cationic surfactants include C1-C20 alkyltrimethylammonium bromide, C1-C30 alkylpyridinium bromide, imidazolinium laurate and the like, but industrially available ones can be used without problems. available and not limited to those listed above. More specific examples of cationic surfactants include alkyltrimethylammonium bromide, alkylpyridinium bromide, imidazolinium laurate, and the like.

Examples of amphoteric surfactants include carboxylate type, sulfate type, sulfonate type, and phosphate type.

[Other ingredients]
The curing agent composition of this embodiment may further contain other components in addition to the hydrophilic polyisocyanate composition and the ionic surfactant described above. Other components include, but are not limited to, solvents, curing accelerator catalysts, antioxidants, UV absorbers, light stabilizers, pigments, leveling agents, plasticizers, rheology control agents, polymerization inhibitors, etc. is mentioned.

Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene; alcohol compounds such as methanol, ethanol, i-propanol, n-butanol, n-hexanol and 2-ethylhexanol; acetone and methyl ethyl ketone. Ketone compounds such as ethyl acetate, acetate-n-butyl, ethyl glycol acetate, methoxypropyl acetate, ester compounds such as isoacetate-3-hydroxy-2,2,4-trimethylpentyl; butyl glycol, tetrahydrofuran, dioxane, ethyl Ethers, such as glycol ether, etc. can be mentioned.

The content of the solvent is preferably 0% by mass or more and 90% by mass or less, more preferably 0% by mass or more and 50% by mass or less, relative to the total mass of the curing agent composition of the present embodiment. More preferably, it is 0% by mass or more and 30% by mass or less.

When the curing agent composition of the present embodiment contains a curing accelerator catalyst, an antioxidant, a light stabilizer, and a polymerization inhibitor, the content of the solvent is 0 mass with respect to the total mass of the hydrophilic polyisocyanate composition. % or more and 10 mass % or less, more preferably 0 mass % or more and 5 mass % or less, and even more preferably 0 mass % or more and 2 mass % or less.

The curing accelerator catalyst is not particularly limited, but for example, dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, dimethyltin dineodecanoate, tin-based compounds such as bis(2-ethylhexanoic acid) tin; 2-ethyl zinc compounds such as zinc hexanoate and zinc naphthenate; titanium compounds such as titanium 2-ethylhexanoate and titanium diisopropoxybis(ethylacetonate); cobalt compounds such as cobalt 2-ethylhexanoate and cobalt naphthenate; bismuth compounds such as bismuth ethylhexanoate and bismuth naphthenate; zirconium compounds such as zirconium tetraacetylacetonate, zirconyl 2-ethylhexanoate and zirconyl naphthenate; and amine compounds.

Examples of antioxidants include, but are not particularly limited to, hindered phenol compounds, phosphorus compounds, sulfur compounds, and the like.

Examples of the ultraviolet absorber include, but are not particularly limited to, benzotriazole-based compounds, triazine-based compounds, and benzophenone-based compounds.

Examples of light stabilizers include, but are not limited to, hindered amine compounds, benzotriazole compounds, triazine compounds, benzophenone compounds, and benzoate compounds.

Examples of pigments include, but are not limited to, titanium oxide, carbon black, indigo, quinacridone, pearl mica, and aluminum.

Examples of the leveling agent include, but are not limited to, silicone oil.

Examples of plasticizers include, but are not particularly limited to, phthalates, phosphoric acid compounds, polyester compounds, and the like.

Examples of rheology control agents include, but are not limited to, hydroxyethylcellulose, urea compounds, microgels, and the like.

Examples of polymerization inhibitors include hydroquinones, phenols, cresols, catechols, and benzoquinones. Specific examples of polymerization inhibitors include benzoquinone, p-benzoquinone, p-toluquinone, p-xyloquinone, naphthoquinone, 2,6-dichloroquinone, hydroquinone, trimethylhydroquinone, catechol, pt-butylcatechol, 2, 5-di-t-butylhydroquinone, monomethylhydroquinone, p-methoxyphenol, 2,6-di-t-butyl-p-cresol, hydroquinone monomethyl ether and the like.

<Method for producing curing agent composition>
The curing agent composition of the present embodiment comprises a step (adding step) of adding the above ionic surfactant to the above hydrophilic polyisocyanate composition and mixing them to obtain a curing agent composition.
The addition step may be performed after the reaction step in the method for producing a hydrophilic polyisocyanate composition described above, or may be performed simultaneously with the reaction step.
The steps of the method for producing the curing agent composition of the present embodiment are described in detail below.

[Addition process]
In the addition step, the content of the ionic surfactant is 0.1% by mass or more and 20% by mass or less with respect to the total solid content of the hydrophilic polyisocyanate composition and the ionic surfactant. It is preferably added, and more preferably added so as to be 0.5% by mass or more and 10% by mass or less.
By adding so that the content of the ionic surfactant is equal to or higher than the above lower limit, the hydrophobic group forms a layer on the surface of the polyisocyanate oil droplets when dispersed in water. As a result, the isocyanate groups in the polyisocyanate are less likely to come into contact with water, so that the isocyanate groups are more likely to be retained.
On the other hand, by adding the ionic surfactant so that the content is equal to or less than the above upper limit, the amount of water absorbed can be reduced, so that the water resistance of the coating film is further improved.

<Physical properties>
Next, the physical properties of the curing agent composition of this embodiment will be described in detail below.

[Content of ionic surfactant]
In the curing agent composition of the present embodiment, the content of the ionic surfactant with respect to the total solid content of the hydrophilic polyisocyanate composition and the ionic surfactant is 0.1% by mass or more and 20% by mass or less. is preferred, and more preferably 0.5% by mass or more and 10% by mass or less.
When the content of the ionic surfactant is at least the above lower limit, the hydrophobic groups form a layer on the surface of the oil droplets of the hydrophilic polyisocyanate composition when dispersed in water. As a result, contact between the isocyanate groups in the hydrophilic polyisocyanate composition and water is reduced, so that the retention of the isocyanate groups can be further enhanced.
On the other hand, when the content of the ionic surfactant is equal to or less than the above upper limit, the amount of water absorbed can be reduced, so that the water resistance of the coating film is further improved.
The content of the ionic surfactant can be calculated using the method described in Examples below.

≪Water-based coating composition≫
A water-based coating composition according to one embodiment of the present invention includes the hydrophilic polyisocyanate composition of the above embodiment or the curing agent composition of the above embodiment, water, and an active hydrogen compound.
By containing an active hydrogen compound, the water-based coating composition of the present embodiment reacts with the isocyanate group of the hydrophilic polyisocyanate composition and the active hydrogen of the active hydrogen compound under various conditions to form a coating film. It tends to be excellent in flexibility, adhesion and conformability to the substrate when it is .

<Constituent>
The constituent components of the water-based coating composition of the present embodiment are described in detail below.

[Active hydrogen compound]
The active hydrogen compound is not particularly limited as long as it is a compound in which two or more active hydrogen atoms are bonded in the molecule. Specific examples of active hydrogen compounds include polyamines, alkanolamines, polythiols, and polyols. Among them, polyol is preferable as the active hydrogen compound.

○ Polyamines Polyamines are not particularly limited, but examples 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, Cyclic polyamines such as 16-hexaazacyclooctadecane, 1,4,7,10-tetraazacyclodecane, 1,4,8,12-tetraazacyclopentadecane, and 1,4,8,11-tetraazacyclotetradecane is mentioned.

○Alkanolamine Examples of alkanolamine include, but are not limited to, monoethanolamine, diethanolamine, aminoethylethanolamine, N-(2-hydroxypropyl)ethylenediamine, mono-, di-(n- or iso-)propanolamine. , ethylene glycol-bis-propylamine, neopentanolamine, methylethanolamine and the like.

○ Polythiol Examples of polythiol include, but are not particularly limited to, bis-(2-hydrothioethyloxy)methane, dithioethylene glycol, dithioerythritol, dithiothreitol and the like.

○ Polyols Polyols are not particularly limited, but examples thereof include polyester polyols (including polycaprolactones), acrylic polyols, polyether polyols, polyolefin polyols, fluorine polyols, polycarbonate polyols, epoxy resins, and the like.
Examples of polyester polyols (including polycaprolactones), acrylic polyols, polyether polyols, and polyolefin polyols include those exemplified in the hydrophilic polyisocyanate composition described above.

(Fluorine polyol)
A fluoropolyol is a polyol containing fluorine in its molecule. Specific examples of fluorine polyols include, for example, fluoroolefins, cyclovinyl ethers, and cyclovinyl ethers disclosed in JP-A-57-34107 (reference 2) and JP-A-61-275311 (reference 3). Copolymers such as hydroxyalkyl vinyl ethers and monocarboxylic acid vinyl esters can be mentioned.

(polycarbonate polyol)
Polycarbonate polyols are not particularly limited, but for example, low-molecular-weight carbonate compounds such as dialkyl carbonates such as dimethyl carbonate, alkylene carbonates such as ethylene carbonate, diaryl carbonates such as diphenyl carbonate, and low-molecular-weight polyols used in the polyester polyols described above and those obtained by condensation polymerization.

(Epoxy resin)
Examples of epoxy resins include, but are not limited to, novolac type epoxy resins, glycidyl ether type epoxy resins, glycol ether type epoxy resins, epoxy type aliphatic unsaturated compounds, epoxy type fatty acid esters, ester type polycarboxylic acids, Examples include aminoglycidyl type epoxy resins, β-methyl epichloro type epoxy resins, cyclic oxirane type epoxy resins, halogen type epoxy resins, resorcin type epoxy resins, and the like.

○Hydroxyl value of polyol The hydroxyl value of the polyol is not particularly limited, but is 10 mgKOH/g or more and 300 mgKOH/g or less per 1 g of the water-based coating composition of the present embodiment from the viewpoint of the crosslink density and mechanical properties of the cured product. more preferably 20 mgKOH/g or more and 250 mgKOH/g or less, and even more preferably 30 mgKOH/g or more and 200 mgKOH/g or less.

[Other ingredients]
The water-based coating composition of the present embodiment may further contain other components in addition to the above-described hydrophilic polyisocyanate composition or the above-described curing agent composition, water, and active hydrogen compound. Other components include, for example, other curing agents such as melamine-based curing agents and epoxy-based curing agents; other additives and the like.

○Other curing agents (melamine-based curing agents)
The melamine-based curing agent is not particularly limited, but includes, for example, a completely alkyl-etherified melamine resin, a methylol group-type melamine resin, and an imino group-type melamine resin partially containing imino groups.

When using a melamine curing agent, addition of an acidic compound is effective.
Examples of acidic compounds include carboxylic acids, sulfonic acids, acidic phosphates, and phosphites.

Examples of carboxylic acids include, but are not limited to, acetic acid, lactic acid, succinic acid, oxalic acid, maleic acid, and decanedicarboxylic acid.
Examples of sulfonic acid include, but are not particularly limited to, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenedisulfonic acid and the like.
Examples of acidic phosphates include, but are not limited to, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, dilauryl phosphate, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, and the like.
Examples of phosphites include, but are not limited to, diethyl phosphite, dibutyl phosphite, dioctyl phosphite, dilauryl phosphite, monoethyl phosphite, monobutyl phosphite, monooctyl phosphite, and monolauryl phosphite. etc.

(epoxy curing agent)
Examples of epoxy curing agents include, but are not limited to, aliphatic polyamines, alicyclic polyamines, aromatic polyamines, acid anhydrides, phenol novolacs, polymercaptans, aliphatic tertiary amines, aromatic tertiary amines, and imidazole. compounds, Lewis acid complexes, and the like.

○ Other additives Other additives include, but are not limited to, inorganic pigments, organic pigments, extender pigments, silane coupling agents, titanium coupling agents, organic phosphates, organic phosphites, and additives. Viscous agent, leveling agent, thixotropic agent, antifoaming agent, freeze stabilizer, matting agent, cross-linking reaction catalyst, anti-skinning agent, dispersant, wetting agent, filler, plasticizer, lubricant, reducing agent, preservative agents, anti-mold agents, deodorants, anti-yellowing agents, ultraviolet absorbers, anti-static agents or charge control agents, anti-settling agents, surfactants, antioxidants, light stabilizers, polymerization inhibitors, etc. various additives that are typically added to paints.

<Method for producing water-based coating composition>
The method for producing the water-based coating composition of the present embodiment is not particularly limited, but for example, a method of adding water and an active hydrogen compound to the above-described hydrophilic polyisocyanate composition or the above-described curing agent composition and mixing them. etc.

<Physical properties>
Next, the physical properties of the water-based coating composition of this embodiment will be described in detail below.

[Isocyanate group/active hydrogen group]
In the aqueous coating composition of the present embodiment, the ratio of the number of isocyanate groups possessed by the hydrophilic polyisocyanate in the aqueous coating composition to the number of active hydrogen groups possessed by the active hydrogen compound in the aqueous coating composition (isocyanate Group/active hydrogen group) is not particularly limited, but is preferably 1/10 or more and 10/1 or less, more preferably 1/8 or more and 8/1 or less, and 1/6 or more and 6/1 or less. is more preferable.
As for isocyanate group/active hydrogen, the average number of isocyanate functional groups is calculated using the method for calculating the average number of isocyanate functional groups described later in Examples. It can then be calculated by dividing the resulting average number of isocyanate functional groups by the number of active hydrogen groups and multiplying by 100.

<Application>
The water-based coating composition of the present embodiment includes, for example, curable compositions such as coating compositions, 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; and additives.

The adherend to which the water-based coating composition of the present embodiment can be used is not particularly limited, but examples thereof include glass; various metals such as aluminum, iron, galvanized steel plate, copper, and stainless steel; wood, paper, mortar, stone, and the like. Fluorine-coated, urethane-coated, acrylic-urethane-coated, etc. Sealant cured products such as silicone-based cured products, modified silicone-based cured products, and urethane-based cured products; Rubbers such as natural rubber and synthetic rubber Leathers such as natural leather and artificial leather; Fibers such as vegetable fiber, animal fiber, carbon fiber, glass fiber, and non-woven fabric; Resins such as polyvinyl chloride, polyester, acrylic, polycarbonate, triacetyl cellulose, and polyolefin films and plates of the type; UV-curable acrylic resin layers; ink layers such as printing ink layers and UV ink layers;

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. .

≪Test item≫
The hydrophilic polyisocyanate compositions, curing agent compositions and coating films produced in Examples and Comparative Examples were measured for physical properties and evaluated according to the methods described below.

<Physical properties 1> Viscosity The viscosity at 25°C of the hydrophilic polyisocyanate compositions or curing agent compositions produced in Examples and Comparative Examples was determined using an E-type viscometer RE-80U (manufactured by Toki Sangyo Co., Ltd.). rice field.

<Physical properties 2> Solid content When the hydrophilic polyisocyanate compositions or curing agent compositions produced in Examples and Comparative Examples are used as samples and diluted with a solvent, the solid content is calculated according to the method shown below. did.
Specifically, first, the mass (W1) [g] of the aluminum cup was accurately weighed, about 1 g of the sample was put therein, and the cup mass (W2) [g] before heat drying was accurately weighed. The cup containing the above sample was then heated in a dryer at 105° C. for 3 hours. Next, after cooling the heated cup to room temperature, the mass (W3) [g] of the cup was accurately weighed again. The mass % of the dry residue in the sample was defined as the solid content (C). The solid content was calculated using the formula (a) shown below.
In the case of no solvent dilution, the solid content was treated as substantially 100%.
Solid content (C) [% by mass]=(W 3 −W1)/(W 2 −W1)×100 (a)

<Physical Property 3> Content of ionic surfactant with respect to total solid content of hydrophilic polyisocyanate composition and ionic surfactant1. Content of ionic surfactant in curing agent composition (D1) [% by mass]
Using the curing agent compositions produced in Examples and Comparative Examples as samples, the content (D1) [% by mass] of the ionic surfactant in the curing agent composition was separated by liquid chromatography, followed by mass spectrometry. Measured using a device. The apparatus and conditions used are as follows.

(Measurement condition)
LC device: UPLC (trade name) manufactured by Waters
Column: Waters, ACQUITY UPLC HSS T3 C18, 1.8 μm, 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 ratio is a / b = 98/2, the ratio of b is linearly increased after sample injection, and after 10 minutes a /b=0/100.
Detection method 1: photodiode array detector, measurement wavelength is 220 nm
Detection method 2: mass spectrometer, manufactured by Waters, Synapt G2 (trade name)
Ionization mode: electrospray ionization, positive ion detection Scan range: m/z 100-2000

2. Content of ionic surfactant relative to total solid content of hydrophilic polyisocyanate composition and ionic surfactant (D2) [% by mass]
Next, the content of the ionic surfactant (D2) [mass%] relative to the total solid content of the hydrophilic polyisocyanate composition and the ionic surfactant is the solid content (C) [mass %] and the content (D1) of the ionic surfactant in the curing agent composition measured in "1."
Content of ionic surfactant relative to total solid content of hydrophilic polyisocyanate composition and ionic surfactant (D2) [% by mass]
= D1/C×100 (b1)

However, if the solid content (C) contains other components (C1) [% by mass] other than the hydrophilic polyisocyanate composition and the ionic surfactant, it is calculated using the formula (b2) shown below. did.
Content of ionic surfactant relative to total solid content of hydrophilic polyisocyanate composition and ionic surfactant (D2) [% by mass]
=D1/(C−C1)×100 (b2)

In the case of a curing agent composition that does not contain a solvent, the same method as in "1." The active agent content (D2) was calculated.

<Physical Property 4> Isocyanate Group Content in Hydrophilic Polyisocyanate Composition1. Isocyanate group content (E1) in the curing agent composition [% by mass]
Using the curing agent compositions produced in Examples and Comparative Examples as samples, the isocyanate group content (E1) was determined according to the method described in JIS K7301-1995 (tolylene diisocyanate type prepolymer test method for thermosetting urethane elastomer). ,It was measured. A more specific measuring method is shown below.

(1) 1 g of sample ((W4) [g]) was collected in a 200 mL Erlenmeyer flask, and 20 mL of toluene was added to the flask to dissolve the sample.
(2) After that, 20 mL of a 2.0 N di-n-butylamine-containing toluene solution was added to the flask, and the mixture was allowed to stand for 15 minutes.
(3) 70 mL of 2-propanol was added to the flask and dissolved to obtain a solution.
(4) The solution obtained in (3) above was titrated with 1 mol/L hydrochloric acid to obtain the sample titer (V1).
(5) Even when no sample was added, measurements were carried out in the same manner as in (1) to (3) above to obtain a blank titer (V2).
The isocyanate group content was calculated using the following formula (c1) from the mass (W4) of the sample and the sample titer (V1) and blank titer (V2) obtained above.
Isocyanate group content (E1) in the curing agent composition [% by mass]
= (V2-V1) x 42/(W4 x 1,000) x 100 (c1)

2. Isocyanate group content (E2) in the hydrophilic polyisocyanate composition [mass%]
The isocyanate group content (E2) [mass%] in the hydrophilic polyisocyanate composition is the solid content (C) measured in "Physical Properties 2" and the ionic interface measured in "2." It was calculated from the activator content (D2) and the isocyanate group content (E1) in the curing agent composition measured in "1." using the following formula (c2).
Isocyanate group content (E2) in the hydrophilic polyisocyanate composition [mass%]
=E1/(C/100)/(100-D2)×100 (c2)

However, if the solid content (C) contains other components (C1) [% by mass] other than the hydrophilic polyisocyanate composition and the ionic surfactant, it is calculated using the formula (c3) shown below. did.
Isocyanate group content (E2) in the hydrophilic polyisocyanate composition [mass%]
=E1/(C/100)/(100-D2-C1)×100 (c3)

In the case of a hydrophilic polyisocyanate composition containing neither an ionic surfactant nor a solvent, the isocyanate in the hydrophilic polyisocyanate composition is measured using the same method as the measurement method described in "1." above. The group content (E2) [% by mass] was calculated.

<Physical properties 5> Number average molecular weight and weight average molecular weight Hydrophilic polyisocyanate compositions or curing agent compositions produced in Examples and Comparative Examples were used as samples, and hydrophilic polyisocyanates containing hydrophilic polyisocyanates and unreacted polyisocyanates were used. The number average molecular weight (F1) and weight average molecular weight (F2) of the isocyanate composition were measured. Specifically, the polystyrene-based number average molecular weight and weight average molecular weight were measured by gel permeation chromatography (GPC) using the following apparatus and conditions. When the curing agent composition is used as a sample, the sensitivity of the ionic surfactant is low under the following measurement conditions. Values of number average molecular weight and weight average molecular weight were used.

(Measurement condition)
Apparatus: HLC-8120GPC (trade name) manufactured by Tosoh Corporation
Column: manufactured by Tosoh Corporation, TSKgelSuperH1000 (trade name) × 1, TSKgelSuperH2000 (trade name) × 1, TSKgelSuperH3000 (trade name) × 1 Carrier: Tetrahydrofuran Detection method: Differential refractometer

<Physical Property 6> Average Number of Isocyanate Functional Groups The average number of isocyanate functional groups (G) is the number of isocyanate functional groups statistically possessed by one molecule of hydrophilic polyisocyanate. The number average molecular weight (F1) of the hydrophilic polyisocyanate measured in "Physical Properties 5", and the isocyanate group content (E2) in the hydrophilic polyisocyanate composition measured in "2." of "Physical Properties 4". , it was calculated using the following formula (d).
Average number of isocyanate functional groups (G)=F1×E2/100/42 (d)

<Physical property 7> (B) / (A)
Using a hydrophilic polyisocyanate composition or a curing agent composition as a sample, a hydrophilic polyisocyanate obtained by reacting a polyisocyanate obtained from 3 molecules of diisocyanate in the composition with 1 molecule of the hydrophilic compound (A). The molar ratio ((B)/(A)) of the hydrophilic polyisocyanate (B) obtained by reacting the polyisocyanate obtained from 3 molecules with 2 or 3 molecules of the hydrophilic compound was calculated. Specifically, first, the sample was separated by liquid chromatography and then measured using a mass spectrometer to calculate the molar ratio ((B)/(A)). When the curing agent composition is used as a sample, the sensitivity of the ionic surfactant is low under the following measurement conditions, so the obtained molar ratio was used as the value of the molar ratio in the curing agent composition. . The apparatus and conditions used are as follows.

(Measurement condition)
LC device: UPLC (trade name) manufactured by Waters
Column: Waters, ACQUITY UPLC HSS T3 C18, 1.8 μm, 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 ratio is a / b = 98/2, the ratio of b is linearly increased after sample injection, and after 10 minutes a /b=0/100.
Detection method 1: photodiode array detector, measurement wavelength is 220 nm
Detection method 2: mass spectrometer, manufactured by Waters, Synapt G2 (trade name)
Ionization mode: electrospray ionization, negative ion detection Scan range: m/z 100-2000

<Physical properties 8> (P) / {(P) + (A) + (B)}
Using the hydrophilic polyisocyanate composition or the curing agent composition as a sample, the molar ratio ((P)/{(P)+(A)+(B)}) was quantified by the same analytical method as in Physical Property 7 above.
Here, (P) is a polyisocyanate obtained from 3 molecules of diisocyanate in the composition and to which the hydrophilic compound has not reacted.
(A) is, as described above, a hydrophilic polyisocyanate obtained by reacting a polyisocyanate obtained from 3 diisocyanate molecules in the composition with 1 molecule of the hydrophilic compound.
(B) is, as described above, a hydrophilic polyisocyanate obtained by reacting a polyisocyanate obtained from 3 diisocyanate molecules in the composition with 2 or 3 molecules of the hydrophilic compound.

<Physical property 9> (Y) / (X)
Using the hydrophilic polyisocyanate composition or the curing agent composition as a sample, GPC was performed under the following measurement conditions. As a result, the height (X) of the UV absorption peak at the retention time (around 11.7 minutes) corresponding to the molecular weight of the diisocyanate trimer (isocyanurate trimer) and the molecular weight of the diisocyanate tetramer and the height (Y) of the UV absorption peak at the retention time. From the obtained (X) and (Y), the ratio of (Y) to (X) ((Y)/(X)) was calculated. The retention time corresponding to the molecular weight of the diisocyanate tetramer is the UV absorption peak of the diisocyanate trimer (around 11.7 minutes) and the UV absorption peak of the diisocyanate pentamer (around 11.0 minutes). is the time at the peak seen between

(Measurement condition)
Carrier: THF
Column: "TSKgel SuperH1000", "TSKgel SuperH2000", "TSKgel SuperH3000" (all manufactured by Tosoh Corporation) column series connected Detector: UV (used when calculating height ratio, measurement wavelength: 254 nm)
Refractometer (used to identify diisocyanate trimers and pentamers)
GPC device: "HLC-8120GPC" (manufactured by Tosoh Corporation)

<Evaluation 1> Storage Viscosity Stability of Hydrophilic Polyisocyanate Composition or Curing Agent Composition A sample of the hydrophilic polyisocyanate composition or curing agent composition was placed in a 50 mL well-dried glass bottle and sealed with nitrogen. It was then stored in an oven at 60°C for 2 months. The viscosity of the hydrophilic polyisocyanate composition or curing agent composition before and after storage was measured. Then, the viscosity increase rate (%) was calculated using the following formula (e).
Thickening rate (%) = (viscosity after storage)/(viscosity before storage) x 100 (e)

Then, based on the following evaluation criteria, viscosity stability (rate of viscosity increase during storage under high temperature conditions) was evaluated.
(Evaluation criteria)
○: Less than 5% thickening rate △: Less than 5% to less than 10% thickening rate ×: 10% or more thickening rate

<Evaluation 2> Water Dispersibility of Hydrophilic Polyisocyanate Composition or Curing Agent Composition (1) Total mass (W5) of 100 mL flask and Yoshino paper was measured.
(2) The hydrophilic polyisocyanate compositions or curing agent compositions produced in Examples and Comparative Examples were collected in a 100 mL flask so as to have a solid content of 16 g ((W6) [g]), and deionized. 24 g of water were added.
(3) Using a propeller blade, the solution in the 100 mL flask was stirred at 200 rpm for 3 minutes, and then filtered through the Yoshino paper weighed in (1).
(4) The filtration residue remaining on the Yoshino paper and the residue remaining in the 100 mL flask were combined and heated in a dryer at 105°C for 1 hour to determine the mass ((W7) [g]).
(5) Using the formula (f) shown below, the proportion (H) of the hydrophilic polyisocyanate composition or the curing agent composition dispersed in water was calculated.
Percentage dispersed in water (H) [% by mass]
= 100 - (W7 - W5) / (W6 x C) x 100 (f)

(6) From the ratio (H) of the hydrophilic polyisocyanate composition dispersed in water calculated in (5), the water dispersibility of the hydrophilic polyisocyanate composition was evaluated according to the following evaluation criteria.
(Evaluation criteria)
○: (H) is 80% by mass or more, and water dispersion stability is good.
x: (H) is less than 80% by mass, poor in water dispersion stability.

<Evaluation 3> Water dispersion stability of hydrophilic polyisocyanate composition or curing agent composition 0.1 g of hydrophilic polyisocyanate composition or curing agent composition and 100 g of deionized water were weighed into a 200 mL flask. Then, propeller blades were used to stir the solution in the 200 mL flask at 600 rpm for 5 minutes to obtain an aqueous dispersion of the hydrophilic polyisocyanate composition or curing agent composition. After that, it was transferred to a 50 mL glass bottle, and the state of dispersion was observed with the naked eye. The water dispersion stability of the hydrophilic polyisocyanate composition or curing agent composition was evaluated according to the following evaluation criteria.
(Evaluation criteria)
◯: No change was observed even after 3 hours had passed.
Δ: Slight precipitation or separation was observed after 3 hours.
x: Precipitation or separation was observed within 3 hours.

<Evaluation 4> Adhesion of Coating Film Each water-based coating composition produced in Examples and Comparative Examples was applied to an alodine-treated aluminum plate with an applicator to a thickness of 40 μm. Then, it was dried in an atmosphere of 23° C./50% RH for 24 hours to obtain a coating film. The resulting cured coating film was subjected to an adhesion test by the cross-cut method based on JIS K 5600-5-6. The lattice pattern was 1 mm square×100 squares. The adhesion of the coating film was evaluated according to the following evaluation criteria.
(Evaluation criteria)
◯: No peeling at all.
Δ: Peeling is 50% or less.
x: Peeling exceeds 50%.

<Evaluation 5> Flexibility of coating film Using each water-based coating composition produced in Examples and Comparative Examples, except that it was coated on a polypropylene plate, curing was performed using the same method as in "Evaluation 4" above. A coating was obtained. The resulting cured coating film was peeled off from the polypropylene plate, and its breaking elongation was measured using TENSILON RTE-1210 (trade name) manufactured by A&D. The measurement conditions were as follows.

(Measurement condition)
Tensile speed: 20mm/min
Sample size: length 20 mm x width 20 mm x thickness 40 μm
Temperature: 23°C
Humidity: 50%

In addition, the flexibility of the coating film was evaluated according to the following evaluation criteria.
(Evaluation criteria)
○: Breaking elongation of the coating film is 50% or more △: Breaking elongation of the coating film is 25% or more and less than 50% ×: Breaking elongation of the coating film is less than 25%

<Evaluation 6> Followability of the coating film to the substrate Using each water-based coating composition produced in Examples and Comparative Examples, the same method as in "Evaluation 4" above was performed except that it was applied on a tin plate. to obtain a cured coating film. The resulting cured coating film was subjected to a flex resistance test (cylindrical mandrel method) based on JIS K 5600-5-1.

[Synthesis Example 1] Production of polyisocyanate compound (PI-1) 1,6-hexamethylene diisocyanate (hereinafter abbreviated as "HDI") was added to a 1 L four-necked glass flask equipped with a thermometer, stirrer and nitrogen seal tube. The flask was heated to 60° C. after replacing the air in the flask with nitrogen. Then, 0.5 part by mass of 2-ethylhexanol (hereinafter sometimes abbreviated as "2-EHOH") was added and stirred for 10 minutes. Next, a 5 mass% isobutanol (hereinafter sometimes abbreviated as "i-BuOH") solution containing benzyltrimethylammonium caprate (hereinafter sometimes abbreviated as "BTMACA") was mixed with BTMACA. It was added over 60 minutes so that the amount was 0.005 parts by weight. The temperature was adjusted to 60±2° C. during the reaction. When the NCO% of the reaction solution reached 43.5% by mass, 0.005 parts by mass of dibutyl phosphate (hereinafter sometimes abbreviated as "DBP") was added as a reaction terminator, and the temperature was raised to 100°C. After reaching 100° C., stirring was continued for 1 hour. The reaction liquid was a colorless and transparent liquid. This reaction solution was filtered through a membrane filter with a pore size of 1 μm to obtain a reaction solution. Next, the obtained reaction liquid is first subjected to thin film distillation, and the treated liquid is heated at 150° C. for 1 hour under vacuum conditions (0.8 Torr) under intermittent UV irradiation while stirring. gone. After the liquid temperature of the treatment liquid reached 150° C., one set of UV irradiation (365 nm) irradiation for 5 minutes and no irradiation for 10 minutes was performed. Then, thin film distillation was performed again to obtain a polyisocyanate compound (PI-1). As a result of measuring the physical properties of the obtained polyisocyanate compound (PI-1) based on the above method, the viscosity was 1400 mPa s, the solid content was 100% by mass, the isocyanate group content was 23.0% by mass, and the average number of isocyanate functional groups was 3.2 and a number average molecular weight of 585.

[Synthesis Example 2] Production of polyisocyanate compound (PI-2) 100 parts by mass of HDI was added to a 1 L four-necked glass flask having a thermometer, a stirrer and a nitrogen seal tube, and the air in the flask was replaced with nitrogen. and held at 60° C. for 2 hours. Next, tetramethylammonium capriate was added as an isocyanurate-forming catalyst to carry out an isocyanurate-forming reaction. After 4 hours, when the NCO% of the reaction solution reached 38.9%, phosphoric acid was added for the reaction. stopped. This reaction solution was filtered through a membrane filter with a pore size of 1 μm to obtain a reaction solution. Next, the resulting reaction liquid was first subjected to thin film distillation to obtain a polyisocyanate compound (PI-2). Regarding the obtained polyisocyanate compound (PI-2), the physical properties were measured based on the above method, and the viscosity was 3000 mPa s, the solid content was 100% by mass, the isocyanate group content was 22.1% by mass, and the average number of isocyanate functional groups was 3.4 and a number average molecular weight of 650.

[Synthesis Example 3] Production of polyisocyanate compound (PI-3) 100 parts by mass of HDI was added to a 1 L four-necked glass flask having a thermometer, a stirrer and a nitrogen seal tube, and the air in the flask was replaced with nitrogen. Then, 0.1 part of isobutanol was added, and the mixture was kept at 80° C. for 2 hours. Next, tetramethylammonium capriate was added as an isocyanurate-forming catalyst to carry out an isocyanurate-forming reaction. After 4 hours, when the NCO% of the reaction solution reached 45.4%, phosphoric acid was added for the reaction. stopped. The reaction solution was further held at 160° C. for 1 hour. This reaction solution was filtered through a membrane filter with a pore size of 1 μm to obtain a reaction solution. Next, the obtained reaction liquid was first subjected to thin film distillation to obtain a polyisocyanate compound (PI-3). Regarding the obtained polyisocyanate compound (PI-3), the physical properties were measured based on the above method, and the viscosity was 600 mPa s, the solid content was 100% by mass, the isocyanate group content was 23.2% by mass, and the average number of isocyanate functional groups was 3.1 and a number average molecular weight of 560.

[Example 1] Production of hydrophilic polyisocyanate composition 1-1 and aqueous coating composition 1-1 (1) Production of hydrophilic polyisocyanate composition 1-1 First, the average number of ethylene oxide repeating units was 9. 4 polyethylene glycol monomethyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name "MPG-130") and polyethylene glycol monomethyl ether with an average number of ethylene oxide repeating units of 4.2 (manufactured by Nippon Nyukazai Co., Ltd., trade name "MPG ”) and were mixed at a mass ratio of 17.3:82.7 to obtain a polyethylene glycol monomethyl ether mixture having an average number of ethylene oxide repeating units of 5.1. Next, a mixture of 10.0 parts by mass of polyisocyanate compound (PI-1) and 15.0 parts by mass of HDI isocyanurate-type polyisocyanate (manufactured by Asahi Kasei Corporation, trade name "Duranate TSA-100"), 18.0 parts by mass of a polyethylene glycol monomethyl ether mixture was mixed and reacted under nitrogen with stirring at 110° C. for 3 hours. Then, 22.0 parts by mass of the polyisocyanate compound (PI-1) and 33.0 parts by mass of Duranate TSA-100 were added, stirred at 110 ° C. for 1 hour, and hydrophilic polyisocyanate composition 1- got 1.

The obtained hydrophilic polyisocyanate composition 1-1 has a viscosity of 1800 mPa s, a solid content of 100% by mass, an isocyanate group content of 14.3% by mass, an average number of isocyanate functional groups of 2.4, a number average molecular weight of 710, (B )/(A) was 42/58, (P)/{(P)+(A)+(B)} was 88.0, and (Y)/(X) was 0.25.

(2) Production of water-based coating composition 1-1 For the hydrophilic polyisocyanate composition 1-1 obtained in (1), acrylic latex with a hydroxyl value per resin of 60 mgKOH / g (manufactured by Asahi Kasei Corporation, trade name “R-5007”) was blended so that the functional group ratio (NCO/OH)=1.25. Then, it was diluted with water to a solid content of 40% by mass to obtain a water-based coating composition 1-1. A coating film was produced using the resulting aqueous coating composition 1-1, and the coating film was evaluated according to the evaluation items described above. The results are shown in Table 1 below.

[Example 2] Production of curing agent composition 2-1 and aqueous coating composition 2-1 (1) Production of curing agent composition 2-1 First, polyethylene glycol having an average number of ethylene oxide repeating units of 9.4 Monomethyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name “MPG-130”) and a methanol solution of sodium dioctyl sulfosuccinate with a solid content of 70% by mass (manufactured by Nippon Nyukazai Co., Ltd., trade name “Newcol 290M”) are solidified. They were mixed at a weight ratio of 9:1. Then, the volatile components (water and methanol) of Newcol 290M were removed by distillation under reduced pressure at 120° C. and 20 Torr to obtain an ionic surfactant-containing polyethylene glycol monomethyl ether. Then, 30.0 parts by mass of the polyisocyanate compound (PI-1) and 20.0 parts by mass of the ionic surfactant-containing polyethylene glycol monomethyl ether are mixed and stirred at 120° C. for 2 hours under nitrogen. reacted. Next, 50.0 parts by mass of polyisocyanate compound (PI-1) was further added and stirred at 120° C. for 1 hour to obtain curing agent composition 2-1.

The obtained curing agent composition 2-1 had a viscosity of 2000 mPa s, a solid content of 100% by mass, and a content of the ionic surfactant with respect to the total solid content of the hydrophilic polyisocyanate composition and the ionic surfactant, It was 2.0% by mass.
The resulting hydrophilic polyisocyanate composition in the curing agent composition 2-1 has an isocyanate group content of 16.6% by mass, an average isocyanate functional group number of 2.9, a number average molecular weight of 730, and (B)/(A) is 30/70, (P)/{(P)+(A)+(B)} was 92.8, and (Y)/(X) was 0.05.

(2) Production of water-based coating composition 2-1 Using the curing agent composition 2-1 obtained in (2), in the same manner as described in (2) of Example 1, water-based coating composition I got product 2-1. A coating film was produced using the resulting aqueous coating composition 2-1, and the coating film was evaluated according to the evaluation items described above. The results are shown in Table 1 below.

[Example 3] Production of curing agent composition 3-1 and aqueous coating composition 3-1 (1) Production of hydrophilic polyisocyanate composition 3-1 Polyethylene glycol monomethyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name “MPG-130”), a methanol solution of sodium dioctyl sulfosuccinate with a solid content of 70% by mass (manufactured by Nippon Nyukazai Co., Ltd., trade name “New Call 290M”), were mixed so that the solid content mass ratio was 9:1. Then, the volatile components (water and methanol) of Newcol 290M were removed by distillation under reduced pressure at 120° C. and 20 Torr to obtain an ionic surfactant-containing polyethylene glycol monomethyl ether. Then, 30.0 parts by mass of the polyisocyanate compound (PI-1) and 20.0 parts by mass of the ionic surfactant-containing polyethylene glycol monomethyl ether are mixed and stirred at 120° C. for 2 hours under nitrogen. , to obtain a curing agent composition 3-1.

The obtained curing agent composition 3-1 had a viscosity of 3200 mPa s, a solid content of 100% by mass, and a content of the ionic surfactant with respect to the total solid content of the hydrophilic polyisocyanate composition and the ionic surfactant, It was 2.0% by mass.
The hydrophilic polyisocyanate composition in the resulting curing agent composition 3-1 had an isocyanate group content of 10.0% by mass, an average isocyanate functional group number of 2.3, a number average molecular weight of 965, and (B)/(A). was 30/70, (P)/{(P)+(A)+(B)} was 79.2, and (Y)/(X) was 0.06.

(2) Production of water-based coating composition 3-1 Using the curing agent composition 3-1 obtained in (1), in the same manner as described in (2) of Example 1, water-based coating composition I got product 3-1. A coating film was produced using the resulting aqueous coating composition 3-1, and the coating film was evaluated according to the evaluation items described above. The results are shown in Table 1 below.

[Comparative Example 1] Production of hydrophilic polyisocyanate composition 1-2 and aqueous coating composition 1-2 (1) Production of hydrophilic polyisocyanate composition 1-2 First, the average number of ethylene oxide repeating units was 9. 4 polyethylene glycol monomethyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name "MPG-130") and polyethylene glycol monomethyl ether with an average number of ethylene oxide repeating units of 4.2 (manufactured by Nippon Nyukazai Co., Ltd., trade name "MPG ”) and were mixed at a mass ratio of 17.3:82.7 to obtain a polyethylene glycol monomethyl ether mixture having an average number of ethylene oxide repeating units of 5.1. Then, polyisocyanate compound (PI-1) 32.0 parts by mass heated to 110 ° C., and HDI isocyanurate-type polyisocyanate (manufactured by Asahi Kasei Corporation, trade name "Duranate TSA-100") 48.0 parts by mass 18.0 parts by mass of the polyethylene glycol monomethyl ether mixture was added to the mixture over 60 minutes while stirring. Further, the mixture was stirred at 110° C. for 1 hour for reaction to obtain a hydrophilic polyisocyanate composition 1-2.

The obtained hydrophilic polyisocyanate composition 1-2 has a viscosity of 1400 mPa s, a solid content of 100% by mass, an isocyanate group content of 14.6% by mass, an average number of isocyanate functional groups of 2.4, a number average molecular weight of 690, (B )/(A) was 15/85, (P)/{(P)+(A)+(B)} was 85.2, and (Y)/(X) was 0.25.

(2) Production of water-based coating composition 1-2 Using the hydrophilic polyisocyanate composition 1-2 obtained in (1), a water-based A coating composition 1-2 was obtained. A coating film was produced using the resulting aqueous coating composition 1-2, and the coating film was evaluated according to the evaluation items described above. The results are shown in Table 1 below.

[Comparative Example 2] Production of curing agent composition 2-2 and aqueous coating composition 2-2 (1) Production of curing agent composition 2-2 First, polyethylene glycol having an average number of ethylene oxide repeating units of 9.4 Monomethyl ether (manufactured by Nippon Nyukazai Co., Ltd., trade name “MPG-130”) and a methanol solution of sodium dioctyl sulfosuccinate with a solid content of 70% by mass (manufactured by Nippon Nyukazai Co., Ltd., trade name “Newcol 290M”) are solidified. They were mixed at a weight ratio of 9:1. Then, the volatile components (water and methanol) of Newcol 290M were removed by distillation under reduced pressure at 120° C. and 20 Torr to obtain an ionic surfactant-containing polyethylene glycol monomethyl ether. Then, 20.0 parts by mass of the ionic surfactant-containing polyethylene glycol monomethyl ether was added to 80.0 parts by mass of the polyisocyanate compound (PI-1) heated to 120° C. over 90 minutes while stirring. Further, the mixture was stirred at 120° C. for 1 hour for reaction to obtain a curing agent composition 2-2.

The obtained curing agent composition 2-2 had a viscosity of 1900 mPa s, a solid content of 100% by mass, and a content of the ionic surfactant with respect to the total solid content of the hydrophilic polyisocyanate composition and the ionic surfactant, It was 2.0% by mass.
The hydrophilic polyisocyanate composition in the resulting curing agent composition 2-2 had an isocyanate group content of 16.8% by mass, an average isocyanate functional group number of 2.9, a number average molecular weight of 725, and (B)/(A). was 11/89, (P)/{(P)+(A)+(B)} was 91.5, and (Y)/(X) was 0.05.

(2) Production of water-based coating composition 2-2 Using the curing agent composition 2-2 obtained in (2), in the same manner as described in (2) of Example 1, water-based coating composition I got product 2-2. A coating film was produced using the resulting aqueous coating composition 2-2, and the coating film was evaluated according to the evaluation items described above. The results are shown in Table 1 below.

[Comparative Example 3] Production of hydrophilic polyisocyanate composition 3-2 and aqueous coating composition 3-2 (1) Production of hydrophilic polyisocyanate composition 3-2 First, the average number of ethylene oxide repeating units11. 85 parts by mass of polyethylene glycol monomethyl ether (manufactured by NOF Co., Ltd., trade name "Uniox M550") of No. 8 and 100 parts by mass of polyisocyanate compound (PI-2) are mixed and heated at 80 ° C. for 6 hours under nitrogen. Stirred. Next, 430 parts by mass of the polyisocyanate compound (PI-3) was further added to the reaction solution, and the mixture was stirred at 110° C. for 1 hour to obtain a hydrophilic polyisocyanate composition 3-2.

The obtained hydrophilic polyisocyanate composition 3-2 had a viscosity of 1800 mPa s, a solid content of 100% by mass, an isocyanate group content of 18.6% by mass, an average isocyanate functional group number of 2.9, a number average molecular weight of 770, (B )/(A) was 30/70, (P)/{(P)+(A)+(B)} was 96.0, and (Y)/(X) was 5.0.

(2) Production of water-based coating composition 3-2 Using the curing agent composition 3-2 obtained in (1), in the same manner as described in (2) of Example 1, water-based coating composition I got product 3-2. A coating film was produced using the resulting aqueous coating composition 3-2, and the coating film was evaluated according to the evaluation items described above. The results are shown in Table 1 below.

In Examples 1, 2 and 3 in which the physical property 7 ((B)/(A)) is 20/80 or more and 50/50 or less, the same raw materials are used, but (B)/(A) is 20/ Evaluation 4 (adhesion) and evaluation 5 (softness) were better than Comparative Examples 1 and 2, which are less than 80.
In addition, regarding the physical property 2 (viscosity), compared with Examples 1 and 2 in which the physical property 7 ((B)/(A)) is 20/80 or more and 50/50 or less, (B)/(A) Comparative Examples 1 and 2, which are less than 20/80, tended to be lower, but were about the same.
In addition, in Example 1 in which (X)/(Y) is 3.0 or less, evaluation 1 (storage viscosity stability) is higher than Comparative Example 3 in which (X)/(Y) is greater than 3.0. It was good.

From the above, it was confirmed that the hydrophilic polyisocyanate composition or the curable composition of the present embodiment undergoes little change in viscosity during storage and is stably dispersed in water. Moreover, it was confirmed that the coating film obtained from the hydrophilic polyisocyanate composition or the curable composition of the present embodiment is excellent in adhesion, flexibility and conformability to substrates.

The hydrophilic polyisocyanate composition and the curable composition of the present embodiment exhibit little change in viscosity during storage, can be stably dispersed in water, and are suitable for water-based coating compositions. The water-based coating composition includes curable compositions such as coating compositions, adhesive compositions, adhesive compositions and casting compositions; various surface treatment compositions such as fiber treatment agents; various elastomer compositions; It is used as a cross-linking agent for foam compositions, modifiers, additives, and the like.

Claims (6)

A polyisocyanate obtained from one or more diisocyanates selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a hydrophilic polyisocyanate obtained by reacting with a hydrophilic compound, the following (1) and (2) ) ,
A hydrophilic polyisocyanate composition , wherein the hydrophilic compound is a compound represented by the following general formula (I) .
(1) In the measurement spectrum of the hydrophilic polyisocyanate composition by gel permeation chromatography (GPC), there are UV absorption peaks of the diisocyanate trimer equivalent and the diisocyanate tetramer equivalent,
The ratio ((Y)/(X)) of the UV absorption peak height (Y) of the tetramer equivalent of the diisocyanate to the UV absorption peak height (X) of the trimer equivalent of the diisocyanate is 0.01 or more and 3 or less;
(2) Among the hydrophilic polyisocyanates, the hydrophilic polyisocyanate (A) obtained by reacting the polyisocyanate obtained from 3 molecules of the diisocyanate with 1 molecule of the hydrophilic compound, the poly obtained from 3 molecules of the diisocyanate The molar ratio ((B)/(A)) of the hydrophilic polyisocyanate (B) obtained by reacting the isocyanate with 2 or 3 molecules of the hydrophilic compound is 20/80 or more and 50/50 or less.

[In general formula (I), R ¹ is an alkylene group having 1 to 4 carbon atoms, and R ² is an alkyl group having 1 to 4 carbon atoms. n is 5 or more and 50 or less. ] The total number of moles of the polyisocyanate (P), which is a polyisocyanate obtained from the three molecules of the diisocyanate and has not reacted with the hydrophilic compound, the hydrophilic polyisocyanate (A), and the hydrophilic polyisocyanate (B). The hydrophilicity according to claim 1, wherein the molar ratio ((P)/{(P) + (A) + (B)}) of the polyisocyanate (P) is 70 % or more and 98 % or less. polyisocyanate composition. 3. The hydrophilic polyisocyanate composition according to claim 1 or 2 , wherein in the general formula (I), ^R1 is an ethylene group, and n is 5 or more and 20 or less. The hydrophilic polyisocyanate composition according to any one of claims 1 to 3 , wherein the polyisocyanate contains one or more selected from the group consisting of isocyanurate groups and biuret groups. Containing the hydrophilic polyisocyanate composition and an ionic surfactant according to any one of claims 1 to 4 , relative to the total solid content of the hydrophilic polyisocyanate composition and the ionic surfactant , a curing agent composition containing 0.1% by mass or more and 20% by mass or less of the ionic surfactant. A water-based coating composition comprising the hydrophilic polyisocyanate composition according to any one of claims 1 to 4 or the curing agent composition according to claim 5 , water, and an active hydrogen compound.