JP2023044204A - One-component moisture-curable polyisocyanate composition, one-component moisture-curable coating composition and coating layer - Google Patents

Abstract

To provide a one-component moisture-curable polyisocyanate composition that has excellent reactivity and gives a coating layer having excellent hardness, initial solvent resistance, and surface smoothness, and a one-component moisture-curable coating composition and a coating layer using the one-component moisture-curable polyisocyanate composition.SOLUTION: A one-component moisture-curable polyisocyanate composition contains a polyisocyanate obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanate and alicyclic diisocyanate, with the number-average functional group number of isocyanate groups being 4.1 or more and 8.0 or less. A one-component moisture-curable coating composition contains the one-component moisture-curable polyisocyanate composition, and a moisture curing accelerator catalyst. A coating layer is prepared by curing the one-component moisture-curable coating composition.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a one-part moisture-curable polyisocyanate composition, a one-part moisture-curable coating composition and a coating film.

Coating compositions using polyisocyanate compositions are widely used as coatings for construction, automobiles, plastics, information appliances, etc., because of their excellent appearance, weather resistance and durability. Above all, in applications that require a high-quality appearance and excellent weather resistance and durability, such as topcoat applications for automobiles and buildings, it is possible to form a dense crosslinked coating film and have a good finished appearance. Liquid polyurethane paints are highly regarded.

In addition, it is known that the polyisocyanate composition can be used as a one-component moisture-curable polyisocyanate composition by reacting with water (water vapor) in the air (see, for example, Patent Documents 1 to 3, etc.). ).

Japanese Patent No. 5536473 Japanese Patent No. 3897410 JP-A-11-322879

However, the conventional one-part moisture-curable coating compositions described in Patent Documents 1 to 3, etc. have problems of low reactivity, poor surface smoothness, and difficulty in developing initial solvent resistance.

The present invention has been made in view of the above circumstances, and is a one-component moisture-curable polyisocyanate composition that is excellent in reactivity and has excellent hardness, initial solvent resistance, and surface smoothness when formed into a coating film. and a one-component moisture-curable coating composition and coating film using the one-component moisture-curable polyisocyanate composition.

That is, the present invention includes the following aspects.
(1) containing a polyisocyanate obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates,
A one-component moisture-curable polyisocyanate composition having an isocyanate group having a number average functionality of 4.1 or more and 8.0 or less.
(2) The one-component moisture-curable polyisocyanate composition according to (1), wherein the content of the allophanate structure derived from a monoalcohol is 35.0% by mass or less relative to the mass of the polyisocyanate.
(3) The one-component moisture-curable polyisocyanate composition according to (1) or (2), wherein the polyisocyanate has a structural unit derived from a polyol having a hydroxyl group number average functionality of 2 or more.
(4) The one-component moisture-curable polyisocyanate composition according to (3), wherein the polyol is at least one polyol selected from the group consisting of aliphatic diols, polyether polyols, polyester polyols, and polycarbonate polyols. .
(5) The one-component moisture-curable polyisocyanate composition according to (3) or (4), wherein the polyol has a number average molecular weight of 80 or more and 2500 or less.
(6) The one-component moisture-curable polyisocyanate composition according to any one of (1) to (5), wherein the one-component moisture-curable polyisocyanate composition has a viscosity of 5000 mPa·s or more.
(7) A one-component moisture-curable coating composition containing the one-component moisture-curable polyisocyanate composition according to any one of (1) to (6) and a moisture-curing acceleration catalyst.
(8) The one-component moisture according to (7), which is used as a top clear coating for building structures, automobile bodies, automobile metal parts, automobile plastic parts, information home appliance metal parts, or information home appliance plastic parts. A curable coating composition.
(9) A coating film obtained by curing the one-component moisture-curable coating composition according to (7) or (8).

According to the one-component moisture-curable polyisocyanate composition of the above aspect, the one-component moisture-curable polyisocyanate composition having excellent reactivity and excellent hardness, initial solvent resistance, and surface smoothness when formed into a coating film. can provide things. The one-component moisture-curable coating composition of the above aspect contains the one-component moisture-curable polyisocyanate composition, has excellent reactivity, and has hardness, initial solvent resistance, and surface smoothness when formed into a coating film. Excellent for The coating film of the above aspect is obtained by curing the one-part moisture-curable coating composition, and is excellent in hardness, initial solvent resistance, and surface smoothness.

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.

As used herein, "polyol" means a compound having two or more hydroxy groups (--OH) in one molecule.
In this specification, "polyisocyanate" means a reactant in which a plurality of monomeric compounds having two or more isocyanate groups (--NCO) are bonded.
In this specification, unless otherwise specified, "(meth)acryl" includes methacryl and acryl, and "(meth)acrylate" includes methacrylate and acrylate.

<<One-component moisture-curable polyisocyanate composition>>
The one-part moisture-curable polyisocyanate composition of the present embodiment contains a polyisocyanate obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

In the one-component moisture-curable polyisocyanate composition of the present embodiment, the number average functionality of the isocyanate group is 4.1 or more and 8.0 or less in a state not diluted with a solvent such as n-butyl acetate, and 4.1 More than 7.8 or less is preferable.
When the number average functional group number of the isocyanate group is at least the above lower limit, the reactivity becomes good. On the other hand, when it is equal to or less than the above upper limit, the surface smoothness of the coated film is improved.
In addition, the number average functional group number of the isocyanate group can be calculated using the following formula as described later in Examples. In the formula, "NCO %" represents the isocyanate group content, and "Mn" represents the number average molecular weight.

"Number average functionality of isocyanate groups" = {(Mn) x (NCO%) x 0.01}/42

The one-component, moisture-curable polyisocyanate composition of the present embodiment has the above-described structure, so that a coating film having excellent reactivity, hardness, initial solvent resistance, and surface smoothness can be obtained. In addition, "initial solvent resistance" refers to the solvent resistance of the coating film immediately after coating (less than 5 hours).

<Polyisocyanate>
The polyisocyanate preferably contains an allophanate structure or an isocyanurate structure.
In the one-component moisture-curable polyisocyanate composition of the present embodiment, all of these structures may be contained in one polyisocyanate, or a mixture of polyisocyanates containing at least one of these structures There may be.

Incidentally, each molar ratio of the allophanate structure and the isocyanurate structure can be determined by ¹³ C-NMR measurement, as described in Examples below.

In the one-component moisture-curable polyisocyanate composition of the present embodiment, the content of the allophanate structure derived from a monoalcohol (monoalcohol-derived allophanate structure) relative to the mass of the polyisocyanate is 35.0% by mass or less. is preferred, 30.0% by mass or less is more preferred, 25.0% by mass or less is even more preferred, and 20.0% by mass or less is particularly preferred. When the content of the allophanate structure derived from the monoalcohol is equal to or less than the above upper limit, the reactivity is excellent, and the hardness and initial solvent resistance of the coating film are excellent.
On the other hand, the lower limit of the content of the allophanate structure derived from the monoalcohol is not particularly limited, but can be, for example, 0.0% by mass.
The content of the allophanate structure derived from the monoalcohol is the molar ratio of the allophanate group determined by ¹³ C-NMR measurement, as described in Examples below, and the molar mass of the allophanate structure derived from the monoalcohol ( g/mol) divided by the sum of the calculated values multiplied by the molar mass (g/mol) of the structure for each component constituting the polyisocyanate, and expressed as a percentage.

[Diisocyanate]
Diisocyanate, which is a raw material for polyisocyanate, is at least one kind of diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

An aliphatic diisocyanate is a compound having a saturated aliphatic group in its molecule. On the other hand, an alicyclic diisocyanate is a compound having a cyclic aliphatic group in its molecule. It is preferable to use an aliphatic diisocyanate because the obtained polyisocyanate composition has a low viscosity.

Aliphatic diisocyanates such as 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, 1,6-diisocyanatohexane (HDI), 1,6-diisocyanato-2,2,4-trimethyl Hexane, methyl 2,6-diisocyanatohexanoate (lysine diisocyanate) and the like can be mentioned.

Examples of alicyclic diisocyanates include 5-isocyanato-1-isocyanatomethyl-1,3,3-trimethylcyclohexane (isophorone diisocyanate; hereinafter sometimes abbreviated as "IPDI"), 1,3-bis ( isocyanatomethyl)cyclohexane (hydrogenated xylylene diisocyanate), bis(4-isocyanatocyclohexyl)methane (hydrogenated diphenylmethane diisocyanate), 1,4-diisocyanatocyclohexane and the like.

These diisocyanates may be used alone or in combination of two or more.

Among them, HDI, IPDI, hydrogenated xylylene diisocyanate, or hydrogenated diphenylmethane diisocyanate is preferable as the diisocyanate because of its industrial availability. HDI is particularly preferred because of its excellent weather resistance and flexibility of the coating film.
Hereinafter, aliphatic diisocyanates and alicyclic diisocyanates may be collectively referred to as diisocyanates.

[Polyol]
The polyisocyanate preferably has a structural unit derived from a polyol having a number-average number of hydroxyl groups of 2 or more.

The number average functional group number of the hydroxyl groups of the polyol is 2 or more, preferably 2 or more and 5 or less, and more preferably 2 or more and 4 or less.
By using a polyol having a number average functionality of hydroxyl groups within the above range, the number average functionality of isocyanate groups of the polyisocyanate can be made within the range described above.

Examples of polyols include aliphatic diols, acrylic polyols, polyether polyols, polyester polyols, polyolefin polyols, silicon-containing polyols, fluorine-containing polyols, polycarbonate polyols, epoxy resins, and alkyd polyols. These polyols may be used alone or in combination of two or more. As the polyol, urethane-modified acrylic polyol, urethane-modified polyester polyol or urethane-modified polyol obtained by modifying acrylic polyol, polyester polyol or polyether polyol with aliphatic diisocyanate, alicyclic diisocyanate or polyisocyanate obtained therefrom. Ether polyols and the like can also be used.
Among them, aliphatic diols, polyether polyols, polyester polyols, or polycarbonate polyols are preferable because they have excellent compatibility with polyisocyanate and can improve surface smoothness due to stress relaxation during curing.

The upper limit of the number average molecular weight of the polyol can be 3500, with 2500 being preferred. On the other hand, the lower limit of the number average molecular weight of the polyol can be 60, preferably 80. That is, the number average molecular weight of the polyol can be 60 or more and 3500 or less, preferably 80 or more and 2500 or less.
When the number average molecular weight of the polyol is at least the above lower limit, the surface smoothness of the coating film becomes better. On the other hand, when the number average molecular weight of the polyol is equal to or less than the above upper limit, the hardness of the coating film becomes better.
The number average molecular weight of the polyol can be obtained by gel permeation chromatography (hereinafter sometimes abbreviated as "GPC") measurement.

[Aliphatic diol]
Aliphatic diols are polyols having aliphatic hydrocarbon groups in their backbones.
Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5- Pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 2-ethyl-1,6-hexanediol, 2-methyl-1,3-propane diol, 3-methyl-1,5-pentanediol, neopentyl glycol and the like.

[Polyether polyol]
Polyether polyols are polyether polyols with oxypropylene groups. The polyether polyol having an oxypropylene group as used herein is a polyether polyol having an oxypropylene group in the molecular chain. In this case, the oxyalkylene repeating unit may contain other oxyalkylene groups such as oxyethylene, oxytetramethylene, oxycyclohexyl or oxystyrene groups.

The content of the oxypropylene group having a side chain is preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 mol% or more, based on the total molar amount of the oxyalkylene repeating units.

Specific examples of polyether polyols include, for example, polypropylene glycol or triol, so-called Pluronic (registered trademark) type polypropylene glycol or triol obtained by addition polymerization of ethylene oxide to the terminal of polypropylene glycol, polyoxypropylene polyoxyethylene copolymer diol. or triol, polyoxypropylene polyoxyethylene block polymer diol or triol, polytetramethylene glycol or triol, polyoxydimethylpropylene polyoxybutylene copolymer diol or triol, polyoxydimethylpropylene polyoxybutylene block polymer diol or triol, polyoxycyclohexane and diols. Among them, as the polyether polyol, polypropylene glycol or triol, or the so-called Pluronic (registered trademark) type polypropylene obtained by addition polymerization of ethylene oxide to the end of polypropylene glycol is used because of its excellent solubility in low-polarity organic solvents. Glycols or triols are preferred. Among them, as the polyether polyol, so-called Pluronic (registered trademark) type polypropylene glycol or triol obtained by addition polymerization of ethylene oxide to the terminal of polypropylene glycol is more preferable because of its excellent reactivity.

These polyether polyols may be used alone or in combination of two or more.

Commercially available polyether polyols include, for example, EXCENOL 840 (trade name, AGC Co., Ltd., polypropylene triol, number average molecular weight: 6500), EXCENOL 510 (trade name, AGC Co., Ltd., polypropylene glycol, number average molecular weight: 4000). , Exenol 230 (trade name, AGC Co., Ltd., polypropylene triol, number average molecular weight 3000), Exenol 3020 (trade name, AGC Co., Ltd., polypropylene glycol, number average molecular weight 3200), Exenol 2020 (trade name, AGC Co., Ltd. Polypropylene glycol, number average molecular weight 2000), Exenol 1030 (trade name, AGC Co., Ltd., polypropylene triol, number average molecular weight 1000), Exenol 1020 (trade name, AGC Co., Ltd., polypropylene glycol, number average molecular weight 1000) , Exenol 410NE (trade name, AGC Co., Ltd., polypropylene pentaerythritol, number average molecular weight 550), Preminol 7012 (trade name, AGC Co., Ltd., polypropylene triol, number average molecular weight 10000), PTG1000SN (trade name, Hodogaya Chemical Co., Ltd., polytetramethylene glycol, number average molecular weight 1000), PTG4000 (trade name, Hodogaya Chemical Co., Ltd., polytetramethylene glycol, number average molecular weight 4000), and the like. Among them, polypropylene glycol is preferable because it has good compatibility and further improves surface smoothness.

As a method for producing polyether polyols, polyhydric alcohols, polyhydric phenols, polyamines, alkanolamines, etc., alone or in mixtures, are treated with propylene oxide (and, if necessary, other alkylene oxides alone or in mixtures) using a catalyst. ) and a production method of dehydrating and condensing a polyhydric alcohol.

The polyhydric alcohol may be a dihydric alcohol or a trihydric alcohol. Dihydric alcohols include, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, bisphenol A and the like. Examples of trihydric alcohols include glycerin and trimethylolpropane. Polyamines include, for example, diamines such as ethylenediamine.

Examples of catalysts include hydroxides such as lithium, sodium, and potassium; strongly basic catalysts such as alcoholates and alkylamines; metal porphyrins; double metal cyanide complexes; Complexes: Examples include composite metal complexes such as zinc hexacyanocobaltate complexes.

Other alkylene oxides include, for example, butylene oxide, cyclohexene oxide, ethylene oxide, and styrene oxide.

[Polyester polyol]
Polyester polyols are those derived from dihydric to trihydric alcohols and ε-caprolactone, ie, reaction products of dihydric to trihydric alcohols and ε-caprolactone. ε-Caprolactone is one of cyclic esters and lactones, and is a seven-membered ring compound represented by the chemical formula: (CH ₂ ) ₅ CO ₂ . Polycaprolactone, which is a polyester polymer, is obtained by ring-opening polymerization of ε-caprolactone.

Examples of divalent to trivalent alcohols include 1,2-propylene glycol, 1,3-butylene glycol, neopentyl glycol, hydroxypivalic acid ester of neopentyl glycol, 2-methyl-1,3 propanediol, 2,3,5-trimethylpentanediol, ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butylenediol, 1,5-pentanediol, 1,6-hexanediol, trimethylolpropane, glycerin, 1,1,7-trimethylolheptane, 1,2,7-trimethylolheptane and the like. These divalent to trivalent alcohols may be used alone or in combination of two or more.

Commercially available polyester polyols include, for example, Polylite (registered trademark) OD-X-2721 (trade name, manufactured by DIC Corporation, polycaprolactone polyol, number average molecular weight: 1000), Polylite (registered trademark) OD-X-2733 ( trade name, manufactured by DIC Corporation, number average molecular weight 300), and the like.

[Polycarbonate polyol]
Polycarbonate polyols have repeating structural units in which two alcohol groups and one carbonate group are dehydrated and condensed. Polycarbonate polyols are composed of a first diol having 2 to 20 carbon atoms, a second diol having 2 to 20 carbon atoms (hereinafter also simply referred to as "two kinds of diols"), and a carbonate compound. is preferably obtained by copolymerizing . This tends to improve workability. The second diol is a diol having 2 or more and 20 or less carbon atoms other than the first diol, and excludes the same type of diol as the first diol.

The method for producing the polycarbonate polyol is not particularly limited. A method of exchange reaction is mentioned. Also, the method of reacting two kinds of diols with a carbonate compound is not particularly limited and includes known methods. Any of a variety of methods described in Schnell, Polymer Reviews, Volume 9, Interscience Publishers, USA, 1964, pages 9-20, may be used.

Examples of the two diols include, but are not particularly limited to, at least one diol selected from the group consisting of aliphatic diols and aromatic diols. Among these, alkylene glycol having two hydroxyl groups and having 2 or more and 20 or less carbon atoms is preferable. By using the alkylene glycol, the polyisocyanate composition tends to have better weather resistance and chemical resistance when used as a coating film. As used herein, the term "alkylene" refers to an optionally branched or alicyclic structure. These diols may be used singly or in combination of two or more.

Specific examples of the two types of diols are not particularly limited, but examples include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1, 4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 2-ethyl-1,6-hexanediol , 2-methyl-1,3 propanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2,2′-bis(4-hydroxy cyclohexyl)-propane, p-xylylenediol, p-tetrachloroxylylenediol, 1,4-dimethylolcyclohexane, bishydroxymethyltetrahydrofuran, di(2-hydroxyethyl)dimethylhydantoin, diethylene glycol, dipropylene glycol, polypropylene glycol , polytetramethylene glycol, 2,6′-dihydroxyethylhexyl ether, 2,4′-dihydroxyethylbutyl ether, 2,5′-dihydroxyethylpentyl ether, 2,3′-dihydroxy-2′,2′-dimethylethylpropyl Ethers, and thioglycols.

Among these, diols having 2 to 11 carbon atoms are preferable, and diols having 3 to 6 carbon atoms are more preferable.

The combination of two diols is not particularly limited, but a combination of a diol having 5 carbon atoms and a diol having 6 carbon atoms, a combination of two or more isomers of a diol having 4 carbon atoms, and a diol having 4 carbon atoms. and a diol having 6 carbon atoms is preferred. By using such two kinds of diols, the spreadability, heat resistance, and water resistance (hydrolysis resistance) of the coating film of the polyisocyanate composition tend to be more excellent. Specific examples of such combinations of two diols include the group consisting of 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 2-methyl-1,3-propanediol. A combination of at least one selected from the above is preferable, and a combination of 1,6-hexanediol and 1,5-pentanediol, a combination of 1,6-hexanediol and 1,4-butanediol, A combination of 2-methyl-1,3 propanediol is more preferred.

Examples of carbonate compounds include, but are not limited to, alkylene carbonates, dialkyl carbonates, diaryl carbonates, and phosgene, and more specifically ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, and diphenyl carbonate. A carbonate is mentioned. Among these, diethyl carbonate is preferable from the viewpoint of ease of production.

Examples of commercially available polycarbonate polyols include Duranol T5650 (trade name, manufactured by Asahi Kasei Corporation, number average molecular weight: 1000).

<Method for producing one-component moisture-curable polyisocyanate composition>
In the production of the one-part moisture-curable polyisocyanate composition of the present embodiment, at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates is used as a raw material, but HDI is preferably used.

For the one-part moisture-curable polyisocyanate composition of the present embodiment, for example, the isocyanurate-forming reaction, allophanat-forming reaction and urethanating reaction can be carried out sequentially or some of them in parallel.

It can also be obtained by carrying out these reactions in the presence of excess diisocyanate monomer and polyol, and removing unreacted diisocyanate monomer after completion of the reaction. A one-pack moisture-curable polyisocyanate composition can also be obtained by mixing the above three reactions separately.

Furthermore, in the method for producing a one-part moisture-curable polyisocyanate composition of the present embodiment, a monoalcohol such as an alkyl monoalcohol can also be used as an auxiliary raw material. Here, when a monoalcohol is used, in the one-part moisture-curable polyisocyanate composition of the present embodiment, the content of the monoalcohol-derived allophanate structure with respect to the mass of the polyisocyanate is preferably 35% by mass or less. . When the said content is below the said upper limit, when it is made into a coating film, hardness will become higher and more favorable solvent resistance will express.

Alternatively, the polyisocyanate composition of the present embodiment can be obtained, for example, by subjecting a diisocyanate to an isocyanurate reaction and an allophanat reaction, followed by a urethanization reaction between the resulting reaction product and a polyol. At this time, the molar ratio NCO/OH of the isocyanate groups in the reaction product to the hydroxyl groups of the polyol is preferably 2/1 or more and 40/1 or less, more preferably 3/1 or more and 30/1 or less, and 4/1 or more and 20/1. 1 or less is more preferable.
Next, the isocyanurate-forming reaction, allophanat-forming reaction, and urethanization reaction are described in detail below.

[Isocyanurate reaction]
When deriving an isocyanurate group-containing polyisocyanate from a diisocyanate monomer, an isocyanurate reaction catalyst is usually used.

As the isocyanurate reaction catalyst, one having basicity is preferred. Examples of such an isocyanurate reaction catalyst include those shown in 1) to 7) below. 1) tetraalkylammonium hydroxides or organic weak acid salts; 2) hydroxyalkylammonium hydroxides or organic weak acid salts; 3) metal salts of alkylcarboxylic acids; 4) metal alcoholates such as sodium and potassium; Aminosilyl group-containing compounds such as silazanes; 6) Mannich bases; 7) combined use of tertiary amines and epoxy compounds.
Examples of tetraalkylammonium include tetramethylammonium and tetraethylammonium.
Examples of weak organic acids include acetic acid and capric acid.
Hydroxyalkylammonium includes, for example, trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, triethylhydroxyethylammonium and the like.
Examples of alkylcarboxylic acids include acetic acid, caproic acid, octylic acid, myristic acid and the like.
Examples of metals constituting metal salts include tin, zinc, lead, sodium, and potassium.
Among them, from the viewpoint of catalytic efficiency, the isocyanurate reaction catalyst is preferably the above 1), 2), 3), 4) or 5), and more preferably the organic weak acid salt of 1).

The amount of the isocyanurate reaction catalyst added is preferably 10 ppm or more and 1000 ppm or less, more preferably 10 ppm or more and 500 ppm or less, and even more preferably 10 ppm or more and 100 ppm or less, relative to the mass of the charged diisocyanate.

The lower limit of the isocyanurate-forming reaction temperature is preferably 50°C, more preferably 54°C, still more preferably 57°C, and particularly preferably 60°C. On the other hand, the upper limit of the isocyanurate-forming reaction temperature is preferably 120°C, more preferably 100°C, still more preferably 90°C, and particularly preferably 80°C.

That is, the isocyanurate-forming reaction temperature is preferably 50°C or higher and 120°C or lower, more preferably 54°C or higher and 100°C or lower, still more preferably 57°C or higher and 90°C or lower, and particularly preferably 60°C or higher and 80°C or lower.
When the isocyanurate-forming reaction temperature is equal to or lower than the above upper limit, it is possible to more effectively prevent changes in properties such as coloring.

[Allophanatization reaction]
An allophanate group-containing polyisocyanate is obtained by adding an alcohol to a diisocyanate and using an allophanatization reaction catalyst. The alcohol used may contain an ether group, an ester group, or a carbonyl group in the molecule, but is preferably a monoalcohol composed of a saturated hydrocarbon group and a hydroxyl group, and more preferably a branched monoalcohol. Such monoalcohols include, for example, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol (isobutyl alcohol), 1-pentanol, 2-pentanol, isoamyl alcohol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, 3,3,5-trimethyl-1-hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol, cyclo pentanol, cyclohexanol, methylcyclohexanol, trimethylcyclohexanol and the like. Among them, as a monoalcohol, because of its particularly excellent solubility in low-polarity organic solvents, isobutanol, 1-butanol, isoamyl alcohol, 1-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1 -hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol or 1,3,5-trimethylcyclohexanol are preferred. Also, due to lower viscosity, 1-propanol, isobutanol, 1-butanol, isoamyl alcohol, 1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2 -octanol, 2-ethyl-hexyl alcohol or 3,3,5-trimethyl-1-hexanol are preferred. In addition, isobutanol, 2-hexanol, 2-octanol, 2-ethyl-1-hexanol or 3,3,5-trimethyl-1-hexanol is preferred because of its very good solubility in low-polarity organic solvents. preferable.

The amount of alcohol added is not limited to the following, but is preferably such that the molar ratio NCO/OH of the isocyanate group of the diisocyanate to the hydroxyl group of the alcohol is 10/1 or more and 1000/1 or less, and is preferably 100/1 or more and 1000/1. The addition amount that makes it 1 or less is more preferable. When the molar ratio of the isocyanate groups of the diisocyanate to the hydroxyl groups of the alcohol is at least the above lower limit, a more appropriate average number of isocyanate groups can be ensured in the obtained polyisocyanate.

Examples of the allophanatization reaction catalyst include, but are not limited to, alkyl carboxylates of tin, lead, zinc, bismuth, zirconium, zirconyl, and the like.
Examples of alkyl carboxylates of tin (organotin compounds) include tin 2-ethylhexanoate and dibutyltin dilaurate.
Examples of lead alkyl carboxylates (organic lead compounds) include lead 2-ethylhexanoate.
Examples of zinc alkylcarboxylates (organozinc compounds) include zinc 2-ethylhexanoate and the like.
Bismuth alkyl carboxylates include, for example, bismuth 2-ethylhexanoate.
Examples of alkyl carboxylates of zirconium include zirconium 2-ethylhexanoate and the like.
Alkyl carboxylates of zirconyl include, for example, zirconyl 2-ethylhexanoate.

When the desired yield is achieved, the allophanatization reaction can be terminated by adding a deactivator for the allophanatization reaction catalyst, such as phosphoric acid or methyl p-toluenesulfonate.

The amount of the allophanatization reaction catalyst used is preferably 10 ppm or more and 10000 ppm or less, more preferably 10 ppm or more and 1000 ppm or less, and even more preferably 10 ppm or more and 500 ppm or less, relative to the raw material diisocyanate.

The allophanatization reaction temperature is preferably 60° C. or higher and 160° C. or lower, more preferably 70° C. or higher and 155° C. or lower, still more preferably 80° C. or higher and 150° C. or lower, and particularly preferably 90° C. or higher and 145° C. or lower.
When the allophanatization reaction temperature is equal to or lower than the above upper limit, it is possible to more effectively prevent changes in properties such as coloring of the resulting polyisocyanate.

The reaction time for allophanatization is preferably 0.2 hours or more and 8 hours or less, more preferably 0.4 hours or more and 6 hours or less, further preferably 0.6 hours or more and 4 hours or less, and 0.8 hours or more and 3 hours or less. It is particularly preferred and most preferably 1.0 hours or more and 2 hours or less.
By setting the reaction time for allophanatization to the above lower limit or more, the viscosity can be further reduced, and by setting the reaction time to the above upper limit or less, the coloring of the polyisocyanate itself can be further suppressed.

Further, the isocyanurate-forming reaction catalyst can be used as an allophanate-forming reaction catalyst. When the allophanatization reaction is performed using the above isocyanurate reaction catalyst, an isocyanurate group-containing polyisocyanate is also produced at the same time. Among them, from the viewpoint of improving productivity from an economic standpoint, it is preferable to perform the allophanatization reaction and the isocyanuration reaction using the above isocyanuration reaction catalyst as the allophanatization reaction catalyst.

[Urethane reaction]
In the method for producing the polyisocyanate composition of the present embodiment, the urethanization reaction is preferably performed after the isocyanurate reaction and the allophanatization reaction. Specifically, the isocyanurate reaction and the allophanatization reaction are performed sequentially or respectively. After obtaining polyisocyanate containing an isocyanurate group and an allophanate group by carrying out in parallel, it is preferable to carry out a urethanization reaction between the obtained polyisocyanate and a polyol.

The lower limit of the urethanization reaction temperature is preferably 80°C, more preferably 100°C. On the other hand, the upper limit of the reaction temperature is preferably 150°C, more preferably 130°C.
That is, the urethanization reaction temperature is preferably 80° C. or higher and 150° C. or lower, more preferably 100° C. or higher and 130° C. or lower.

When the polymerization reaction of the isocyanurate-forming reaction, allophanat-forming reaction and urethanization reaction reaches a desired degree of polymerization, the polymerization reaction is terminated. Termination of the polymerization reaction is not limited to the following, but can be achieved, for example, by adding an acidic compound to the reaction solution to neutralize the polymerization reaction catalyst, or by inactivating it by thermal decomposition, chemical decomposition, or the like. . Examples of acidic compounds include phosphoric acid, acidic phosphate esters, sulfuric acid, hydrochloric acid, and sulfonic acid compounds. After stopping the reaction, filtration is performed if necessary.

Since the reaction solution immediately after stopping the reaction usually contains an unreacted diisocyanate monomer, it is preferable to remove it by a thin film evaporator, extraction, or the like. It is preferable to control the diisocyanate monomer concentration contained in the polyisocyanate composition to 1% by mass or less by performing such a post-treatment.
For example, when the diisocyanate monomer is HDI, the diisocyanate monomer concentration can be measured using the method described in the examples below.

<Physical properties of one-component moisture-curable polyisocyanate composition>
[viscosity]
The viscosity at 25° C. when the solid content of the one-component moisture-curable polyisocyanate composition is 98% by mass or more is preferably 2000 mPa·s or more, more preferably 4000 mPa·s or more, and even more preferably 5000 mPa·s or more. When the viscosity is equal to or higher than the above lower limit, the number of functional groups of isocyanate groups can be sufficiently increased. On the other hand, the upper limit of the viscosity at 25° C. is not particularly limited, but can be, for example, 500,000 or less.
As for the viscosity, a value measured at 25° C. using an E-type viscometer (manufactured by Tokimec Co., Ltd.) can be adopted as described in Examples described later.

[Isocyanate group content (NCO%)]
The isocyanate group content (NCO%) of the one-component moisture-curable polyisocyanate composition is preferably 3.0% by mass or more and 24.0% by mass or less from the viewpoint of performance when it is made into a coating film, and 3.5% by mass. % or more and 23.0 mass % or less is more preferable, and 4.0 mass % or more and 21.0 mass % or less is even more preferable. When the NCO% is at least the above lower limit, the performance of the coating film is better. Form.
NCO% can be determined by back titration with 1N hydrochloric acid after neutralizing the isocyanate groups with excess 2N amine, as described in the examples below.

<Application>
The one-part moisture-curable polyisocyanate composition of the present embodiment can be used as a raw material for paints, inks, adhesives, casting materials, elastomers, foams, and plastic materials.

<<One-component moisture-curable coating composition>>
The one-component moisture-curable coating composition of the present embodiment contains the one-component moisture-curable polyisocyanate composition and a moisture curing acceleration catalyst.
Further, the one-component moisture-curable coating composition of the present embodiment may contain other polyisocyanate compositions in addition to the one-component moisture-curable polyisocyanate composition.

<Moisture Curing Acceleration Catalyst>
Moisture curing acceleration catalysts include, but are not limited to, metal salts, tertiary amines, and the like.
Examples of metal salts include dibutyltin dilaurate, tin 2-ethylhexanoate, zinc 2-ethylhexanoate, cobalt salts and the like.
Examples of tertiary amines include triethylamine, pyridine, methylpyridine, benzyldimethylamine, N,N-dimethylcyclohexylamine, N-methylpiperidine, pentamethyldiethylenetriamine, N,N'-endoethylenepiperazine, N,N' - dimethylpiperazine and the like.

Examples of commercially available moisture curing accelerating catalysts include Nitto Kasei Co., Ltd. trade name "Neostan U-100" (dibutyltin dilaurate) and "Neostan U-810" (dioctyltin dilaurate).

The one-component moisture-curable coating composition of the present embodiment may contain other components such as polyol in addition to the one-component moisture-curable polyisocyanate composition.

<Polyol>
Examples of polyols include acrylic polyols, polyester polyols, polyether polyols, polyolefin polyols, silicon-containing polyols, fluorine-containing polyols, polycarbonate polyols, epoxy resins, and alkyd polyols. These polyols may be used alone or in combination of two or more. As the polyol, urethane-modified acrylic polyol, urethane-modified polyester polyol or urethane-modified polyol obtained by modifying acrylic polyol, polyester polyol or polyether polyol with aliphatic diisocyanate, alicyclic diisocyanate or polyisocyanate obtained therefrom. Ether polyols and the like can also be used.

<Various additives>
The one-component moisture-curable coating composition of the present embodiment, in addition to the one-component moisture-curable polyisocyanate composition and the moisture curing acceleration catalyst, depending on the purpose and application, the one-component moisture-curable coating composition of the present embodiment Coloring pigments, dyes, silane coupling agents for improving the adhesion of coatings, UV absorbers, curing accelerators, light stabilizers, delustering agents, and hydrophilizing coatings to the extent that they do not impair the effects of the composition. It may also contain various additives used in the art, such as agents, dryness improvers, leveling agents, antioxidants, plasticizers, and surfactants.

The color pigment may be an inorganic pigment or an organic pigment. Examples of inorganic pigments include carbon black and titanium oxide, which have good weather resistance. Examples of organic pigments include phthalocyanine blue, phthalocyanine green, quinacridone red, indanthrene orange, and isoindolinone yellow.

Silane coupling agents include, for example, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, ureidopropyltriethoxysilane, vinyltriethoxysilane, Ethoxysilane, Vinyltrimethoxysilane, 3-Methacryloxypropyltrimethoxysilane, 3-Methacryloxypropyltriethoxysilane, 2-(3,4-Epoxycyclohexyl)ethyltrimethoxysilane, 3-Glycidoxypropyltrimethoxysilane , 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, methyltriethoxysilane, methyltrimethoxysilane and the like.

Examples of the ultraviolet absorber include benzophenone-based, benzotriazole-based, triazine-based, and cyanoacrylate-based ultraviolet absorbers.

Examples of light stabilizers include hindered amine-based light stabilizers, etc. Specific commercial products include, for example, Adekastab LA62, Adekastab LA67 (trade names, all manufactured by Adeka Argas Chemicals), Tinuvin 292, Tinuvin 144, Tinuvin 123, Tinuvin 440 (trade name, all manufactured by Ciba Specialty Chemicals), Sanol LS765 (trade name, manufactured by Sankyo Lifetech Co., Ltd.), and the like.

The matting agent includes, for example, ultrafine synthetic silica, etc., and when the matting agent is used, a coating film with an elegant semi-gloss and matte finish can be formed.

A silicate compound is preferable as the coating film surface hydrophilizing agent. By containing the silicate compound, when a coating film is produced using the coating composition of the present embodiment, the coating film surface becomes hydrophilic, and resistance to rain streak staining is exhibited. Since the silicate compound reacts with hydroxyl groups, it is preferably added to the polyisocyanate composition, which is the curing agent component, when mixed in advance. Alternatively, they may be mixed at the same time when the polyol, which is the main component, and the polyisocyanate composition, which is the curing agent component, are mixed.

Examples of silicate compounds include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-tert-butoxysilane, dimethoxydiethoxysilane. , tetraphenoxysilane, condensates thereof, and the like. Among them, the silicate compound is preferably a condensate of tetramethoxysilane or a condensate of tetraethoxysilane, because the surface of the coating film is likely to be hydrophilic when the coating film is produced.

Examples of dryness improvers include CAB (cellulose acetate butrate) and NC (nitrocellulose).

[Leveling agent]
Examples of leveling agents include, but are not limited to, silicones, aerosils, waxes, stearates, and polysiloxanes.

[Plasticizer]
Examples of plasticizers include, but are not limited to, phthalates, phosphates, fatty acid esters, pyromellitic esters, epoxy plasticizers, polyether plasticizers, liquid rubbers, and non-aromatic paraffin oils. etc.
Examples of phthalates include dioctyl phthalate, dibutyl phthalate, diethyl phthalate, butylbenzyl phthalate, di-2-ethylhexyl phthalate, diisodecyl phthalate, diundecyl phthalate, and diisononyl phthalate.
Phosphate esters include, for example, tricresyl phosphate, triethyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, trimethylhexyl phosphate, tris-chloroethyl phosphate, tris-dichloropropyl phosphate and the like.
Examples of fatty acid esters include trimellitic acid esters, dipentaerythritol esters, dioctyl adipate, dimethyl adipate, di-2-ethylhexyl azelate, dioctyl azelate, dioctyl sebacate, di-2-ethylhexyl sebacate, and methyl acetyl lysinocate. Examples of trimellitates include octyl trimellitate and isodecyl trimellitate.
Examples of pyromellitic acid esters include pyromellitic acid octyl ester and the like.
Examples of epoxy plasticizers include epoxidized soybean oil, epoxidized linseed oil, and epoxidized fatty acid alkyl esters.
Examples of polyether plasticizers include adipate ether esters and polyethers.
Examples of liquid rubber include liquid NBR, liquid acrylic rubber, and liquid polybutadiene.

[Surfactant]
Examples of surfactants include known anionic surfactants, cationic surfactants, and amphoteric surfactants.

<Method for producing one-component moisture-curable coating composition>
The one-component moisture-curable coating composition of this embodiment is obtained by the production method shown below.
When the one-component moisture-curable coating composition of the present embodiment is a solvent-based coating composition, for example, first, the one-component moisture-curable polyisocyanate composition or its solvent dilution is added with a moisture curing acceleration catalyst, And, if necessary, various additives are added. Then, if necessary, a solvent is further added to adjust the viscosity. A solvent-based coating composition can then be obtained by stirring by hand or by using a stirring device such as a Masellar.

<Application>
The one-part moisture-curable coating composition of the present embodiment is not limited to the following, but for example, spray coating, air spray coating, brush coating, coating by dipping method, roll coating, curtain flow coating, bell coating, electrostatic It can be used as a paint such as coating.

In addition, the one-part moisture-curable coating composition of the present embodiment is also useful as a coating for molded articles composed of materials such as metals (steel plates, surface-treated steel plates, etc.), plastics, wood, films, inorganic materials, and the like. and is particularly suitable as a coating for metals or plastics.

In addition, the one-part moisture-curable coating composition of the present embodiment is suitable for, for example, architectural coatings, heavy-duty anti-corrosion coatings, automotive coatings, information appliance coatings, and information equipment coatings such as personal computers and mobile phones. .
In addition, it is particularly suitable as a top clear paint for building structures, automobile bodies, automobile metal parts, automobile plastic parts, information home appliance metal parts, or information home appliance plastic parts.

≪Paint film≫
The coating film of the present embodiment is obtained by curing the one-component moisture-curable coating composition, and always exhibits stable quality, and is excellent in hardness, initial solvent resistance, and surface smoothness. .

<Method for producing coating film>
The method for producing a coating film of the present embodiment is a method including the step of curing the one-component moisture-curable coating composition.
The coating film of the present embodiment is formed by applying the one-component moisture-curable coating composition to, for example, spray coating, air spray coating, brush coating, coating by a dipping method, roll coating, curtain flow coating, bell coating, and electrostatic coating. It can be produced by coating an object to be coated using a known coating method such as the above, and then curing the coating.

Examples of the object to be coated include those similar to the molded article composed of the material exemplified in the above "<Usage of use of the coating composition>".

Hereinafter, the present embodiment will be described in more detail by showing specific examples and comparative examples, but the present embodiment is not limited by the following examples and comparative examples as long as the gist thereof is not exceeded. .

<Method for measuring physical properties>
[Physical properties 1]
(Content of allophanate structure derived from monoalcohol)
The one-component moisture-curable polyisocyanate composition was subjected to ¹³ C-NMR measurement using Biospin Avance 600 (trade name) manufactured by Bruker. Specific measurement conditions were as follows.

(Measurement condition)
¹³ C-NMR device: AVANCE600 (manufactured by Bruker)
Cryoprobe (manufactured by Bruker)
CryoProbe®
CPDUL
600S3-C/HD-05Z
Resonance frequency: 150MHz
Concentration: 60wt/vol%
Shift reference: CDCl ₃ (77 ppm)
Number of times of integration: 10000 times Pulse program: zgpg30 (proton complete decoupling method, waiting time 2 sec)

Each molar ratio of the monoalcohol-derived allophanate structure and the isocyanurate structure was determined by dividing the integrated value of the following signals by the number of carbon atoms being measured.
Isocyanurate group: (Integral value near 148.6 ppm) ÷ 3
Monoallophanate group: (integral value near 154 ppm) ÷ 1

Next, the molar ratio of allophanate groups determined by ¹³ C-NMR measurement was multiplied by the molar mass (g/mol) of the monoalcohol-derived allophanate structure, and the molar mass of the structure for each component constituting the polyisocyanate was obtained. The percentage of the value obtained by dividing the value obtained by multiplying (g / mol) by the sum of the calculated products is the content of the allophanate structure derived from monoalcohol (hereinafter sometimes simply referred to as "content of allophanate structure") Calculated.

[Physical properties 2]
(Number average functional group number of isocyanate group (average NCO number))
Using a one-component moisture-curable polyisocyanate composition as a sample, the number average functional group number (average NCO number) of the isocyanate groups was determined according to the following formula.

"Average NCO" number = {(Mn) x (NCO%) x 0.01}/42

In the formula, "NCO %" represents the isocyanate group content, and the value obtained in "Physical properties 4" described later was used. In addition, "Mn" represents the number average molecular weight, which was determined as a polystyrene-based molecular weight by performing GPC measurement under the measurement conditions shown below.

(Measurement condition)
Apparatus: HLC-8320GPC (TOSOH)
Column: TSKgelSuperH2500 x 1 (TOSOH)
TSKgel Super H4000 x 1 (TOSOH)
TSKgel Super H5000 x 1 (TOSOH)
TSKgel Super H6000 x 1 (TOSOH)
Carrier: Tetrahydrofuran Flow rate: 0.6 mL/min Sample concentration: 1.0% by mass
Injection volume: 20 μL
Temperature: 40°C
Detection method: differential refractometer

[Physical properties 3]
(Viscosity at 25°C)
The viscosity was measured at 25° C. with an E-type viscometer (manufactured by Tokimec Co., Ltd.). A rotor of 1°34′×R24 was used when the viscosity was less than 20000 mPa·s, and a rotor of 3°×R12 was used when the viscosity was 20000 mPa·s or more. The number of revolutions is as follows.

(Rotor: 1°34'×R24 RPM)
100r. p. m. (When less than 128 mPa s)
50r. p. m. (In the case of 128 mPa s or more and less than 256 mPa s)
20r. p. m. (In the case of 256 mPa·s or more and less than 640 mPa·s)
10r. p. m. (640 mPa·s or more and less than 1280 mPa·s)
5r. p. m. (In the case of 1280 mPa s or more and less than 2560 mPa s)
2.5r. p. m. (In the case of 2560 mPa s or more and less than 5120 mPa s)
1r. p. m. (In the case of 5120 mPa s or more and less than 10240 mPa s)
0.5r. p. m. (In the case of 10240 mPa s or more and less than 20480 mPa s)

(Rotor: 3° x R12 rotation speed)
5r. p. m. (In the case of 20000 mPa s or more and less than 38000 mPa s)
2.5r. p. m. (In the case of 38000 mPa s or more and less than 79000 mPa s)
1r. p. m. (In the case of 79000 mPa s or more and less than 198000 mPa s)
0.5r. p. m. (In the case of 198000 mPa s or more and less than 390000 mPa s)

[Physical properties 4]
(Isocyanate group content (NCO%))
NCO% was determined by back titration with 1N hydrochloric acid after neutralizing the isocyanate groups with an excess of 2N amine.

[Production of one-component moisture-curable coating composition]
30 g of each one-part moisture-curable polyisocyanate composition was adjusted with 20 g of butyl acetate so that the coating solid content was 60% by mass. Furthermore, a moisture curing accelerating catalyst was added to obtain various one-component moisture curing coating compositions. The type and blending amount of the moisture curing accelerating catalyst are shown in the table below.

<Method for evaluating coating film>
[Evaluation 1]
(reactivity)
Each one-part moisture-curable coating composition was applied to a glass plate so that the dry film thickness was 30 μm, and allowed to stand at 23° C. and 50% humidity for 4 hours to cure to obtain each coating film. A dry-to-the-touch test was conducted on the resulting coating film. The reactivity of each coating film was evaluated according to the evaluation criteria shown below.

(Evaluation criteria)
A: Tack-free B: Slightly sticky C: Sticky D: Uncured

[Evaluation 2]
(hardness)
Each one-component moisture-curable coating composition was applied to a glass plate so that the dry film thickness was 30 μm, and allowed to stand at 23° C. and 50% humidity for 24 hours to cure to obtain each coating film. The resulting coating film was tested using a Konig hardness tester (Pendulum hardness tester, trade name, manufactured by BYK Garder). The hardness of each coating film was evaluated according to the evaluation criteria shown below.

(Evaluation criteria)
A: 120 or more B: 100 or more and less than 120 C: 80 or more and less than 100 D: less than 80

[Evaluation 3]
(initial solvent resistance)
Each one-part moisture-curable coating composition was allowed to stand at 23° C. and 50% humidity for 4 hours to cure to give a dry film thickness of 30 μm to obtain each coating film. A xylene rubbing test was performed on the resulting coating film. The hardness of each coating film was evaluated according to the evaluation criteria shown below.

(Evaluation criteria)
A: No scratch even after 20 times or more.
B: Scratched at 15 times or more and 19 times or less.
C: Scratched at 5 times or more and 14 times or less.
D: Scratched 4 times or less.

[Evaluation 4]
(Surface smoothness)
Each one-component moisture-curable coating composition was applied to a white board so that the dry film thickness was 30 μm, and left to stand at 23° C. and 50% humidity for 24 hours to cure to obtain each coating film. The 60° gloss value was measured on the resulting coating. The surface smoothness of each coating film was evaluated according to the evaluation criteria shown below.

(Evaluation criteria)
A: Gloss value of 94% or more B: Gloss value of 90% or more and less than 94% C: Gloss value of 80% or more and less than 90% D: Gloss value of less than 80%

<Synthesis of polyisocyanate>
[Synthesis Example 1]
(Synthesis of polyisocyanate A-1)
A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube and a dropping funnel was filled with a nitrogen atmosphere, and 500 g of HDI and 2 g of isobutyl alcohol were charged and urethanized at 90° C. for 1 hour while stirring. reacted. Tetramethylammonium caprate: 0.05 g was added as an allophanatization and isocyanuration catalyst to carry out an isocyanuration reaction. When the refractive index of the reaction solution increased to 0.020, phosphoric acid was added to terminate the reaction. After filtration of the reaction solution, it was purified twice under conditions of 160° C. and 0.2 Torr using a thin film evaporator to obtain polyisocyanate A-1. The resulting polyisocyanate A-1 has a viscosity of 2800 mPa s (25° C.), an NCO content of 21.5% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 3.4, and an allophanate structure content of 4. .1 mass %.

[Synthesis Example 2]
(Synthesis of polyisocyanate A-2)
500 g of HDI and 1 g of 2-ethylhexanol were charged into the same apparatus as in Synthesis Example 1, and urethanization reaction was carried out at 90° C. for 1 hour while stirring. Thereafter, 0.05 g of tetramethylammonium caprate was added as an isocyanurate-forming catalyst to carry out an isocyanurate-forming reaction. When the increase in the refractive index of the reaction solution reached 0.011, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A2. The obtained polyisocyanate A-2 has a viscosity of 1300 mPa s (25 ° C.), an NCO content of 23.0% by mass, an HDI monomer concentration of 0.11% by mass, an average NCO number of 3.3, and an allophanate structure content of 1. .9 mass %.

[Synthesis Example 3]
(Synthesis of polyisocyanate A-3)
500 g of HDI and 12 g of 2-ethylhexanol were charged into the same apparatus as in Synthesis Example 1, and urethanization reaction was carried out at 90° C. for 1 hour while stirring. 0.05 g of isobutyl alcohol was added to tetramethylammonium caprate as an allophanatization and isocyanuration catalyst to carry out an isocyanuration reaction. When the refractive index of the reaction liquid increased to 0.012, phosphoric acid was added to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A-3. The obtained polyisocyanate A-3 has a viscosity of 600 mPa s (25 ° C.), an NCO content of 20.6% by mass, an HDI monomer concentration of 0.11% by mass, an average NCO number of 2.6, and an allophanate structure content of 33. .2 mass %.

[Synthesis Example 4]
(Synthesis of polyisocyanate A-4)
500 g of HDI and 30 g of 2-ethylhexanol were charged into the same apparatus as in Synthesis Example 1, and urethanization reaction was carried out at 90° C. for 1 hour while stirring. After that, the temperature was raised to 130° C., and 0.35 g of a 20% mineral spirit solution of zirconyl 2-ethylhexanoate was added as an allophanatization catalyst. After 60 minutes, when the refractive index of the reaction solution increased to 0.0055, pyrophosphoric acid (manufactured by Taihei Kagaku Sangyo Co., Ltd., trade name “Phosphoric acid (105%)”) was added to a 39% ethanol solution with a solid content of 0.005%. 47 g was added to stop the reaction. Then, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A-4. The resulting polyisocyanate A-5 has a viscosity of 110 mPa.s. s (25° C.), NCO content 17.1%, HDI monomer concentration 0.15 mass %, average NCO number 2.0, allophanate structure content 96.8 mass %.

[Synthesis Example 5]
(Synthesis of polyisocyanate B-1)
500 g of HDI was charged into the same apparatus as in Synthesis Example 1, and 0.05 g of tetramethylammonium caprate was added as an isocyanurate catalyst to carry out an isocyanurate reaction. When the increase in the refractive index of the reaction solution reached 0.011, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate B-1. The obtained polyisocyanate B-1 has a viscosity of 1400 mPa s (25 ° C.), an NCO content of 23.2% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 3.3, and an allophanate structure content of 0. 0% by mass.

[Synthesis Example 6]
(Synthesis of polyisocyanate B-2)
500 g of HDI was charged into the same apparatus as in Synthesis Example 1, and 0.05 g of tetramethylammonium caprate was added as an isocyanurate catalyst to carry out an isocyanurate reaction. When the refractive index of the reaction solution reached 0.010, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate B-2. The obtained polyisocyanate B-2 has a viscosity of 1300 mPa s (25 ° C.), an NCO content of 23.1% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 3.3, and an allophanate structure content of 0. 0% by mass.

[Synthesis Example 7]
(Synthesis of polyisocyanate B-3)
Polyisocyanate B-2: 100 g and polyether polyol (manufactured by Hodogaya Chemical Industry Co., Ltd., trade name "PTG4000", number average molecular weight 4000, number average functional group number of hydroxyl group 2): 200 g in the same apparatus as in Synthesis Example 1 was charged, and a urethanization reaction was carried out at 120° C. for 6 hours while stirring to obtain polyisocyanate B-3. The obtained polyisocyanate B-3 has a viscosity of 12000 mPa s (25 ° C.), an NCO content of 4.8% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 3.6, and an allophanate structure content of 0. 0% by mass.

<Production of one-component moisture-curable polyisocyanate composition>
[Example 1]
(Production of one-component moisture-curable polyisocyanate composition Pa1)
Polyisocyanate A-3: 100 g, polyether polyol (manufactured by AGC Co., Ltd., trade name "Exenol 1020", number average molecular weight 1000, number average functional number of hydroxyl groups 2): 80 g in the same apparatus as in Synthesis Example 1. was charged, and the urethanization reaction was carried out at 120° C. for 6 hours while stirring to obtain a one-component moisture-curable polyisocyanate composition Pa1. The resulting polyisocyanate A-12 has a viscosity of 35,000 mPa s (25° C.), an NCO content of 7.7% by mass, an HDI monomer concentration of 0.50% by mass, an average NCO number of 4.2, and an allophanate structure content of 18. 0.4 mass %.

[Example 2]
(Production of one-component moisture-curable polyisocyanate composition Pa2)
In the same apparatus as in Synthesis Example 1, polyisocyanate A-2: 100 g and polyester polyol (manufactured by DIC Corporation, trade name "Polylite OD-X-2155", number average molecular weight 1000, number average functional number of hydroxyl groups 2): 70 g of the mixture was charged, and a urethanization reaction was carried out at 120° C. for 6 hours while stirring to obtain a one-component moisture-curable polyisocyanate composition Pa2. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 80000 mPa s (25 ° C.), an NCO content of 10.0% by mass, an HDI monomer concentration of 0.50% by mass, an average NCO number of 4.4, and an allophanate structure. was 1.1% by mass.

[Example 3]
(Production of one-component moisture-curable polyisocyanate composition Pa3)
Polyisocyanate A-1: 100 g and polycarbonate polyol (manufactured by Asahi Kasei Corporation, trade name "Duranol T5651", number average molecular weight: 1000, hydroxyl number average functionality: 2): 65 g were charged into the same apparatus as in Synthesis Example 1. , and under stirring at 120° C. for 6 hours, a urethanization reaction was carried out to obtain a one-component moisture-curable polyisocyanate composition Pa3. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 100000 mPa s (25 ° C.), an NCO content of 9.8% by mass, an HDI monomer concentration of 0.60% by mass, an average NCO number of 4.2, and an allophanate structure. was 2.5% by mass.

[Example 4]
(Production of one-component moisture-curable polyisocyanate composition Pa4)
In the same apparatus as in Synthesis Example 1, polyisocyanate A-2: 100 g and polyether polyol (manufactured by AGC Co., Ltd., trade name "Exenol 2020", number average molecular weight 2000, number average functional number of hydroxyl groups 2): 80 g. After charging, a urethanization reaction was carried out at 120° C. for 6 hours while stirring to obtain a one-pack moisture-curable polyisocyanate composition Pa4. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 28000 mPa s (25 ° C.), an NCO content of 10.9% by mass, an HDI monomer concentration of 0.50% by mass, an average NCO number of 4.1, and an allophanate structure. was 1.1% by mass.

[Example 5]
(Production of one-component moisture-curable polyisocyanate composition Pa5)
Polyisocyanate A-3: 100 g and polyether polyol (manufactured by AGC Co., Ltd., trade name "Exenol 3020", number average molecular weight 3200, number average functional group number of hydroxyl group 2): 100 g were placed in the same apparatus as in Synthesis Example 1. After charging, the urethanization reaction was carried out at 120° C. for 6 hours while stirring to obtain a one-pack moisture-curable polyisocyanate composition Pa5. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 15000 mPa s (25 ° C.), an NCO content of 8.9% by mass, an HDI monomer concentration of 0.50% by mass, an average NCO number of 4.2, and an allophanate structure. was 16.6% by mass.

[Example 6]
(Production of one-component moisture-curable polyisocyanate composition Pa6)
Polyisocyanate A-2: 100 g and polyether polyol (manufactured by Hodogaya Chemical Industry Co., Ltd., trade name "PTG1000", number average molecular weight 1000, number average functional group number of hydroxyl group 2): 70 g in the same apparatus as in Synthesis Example 1 were added and urethanized with stirring at 120° C. for 6 hours to obtain a one-component moisture-curable polyisocyanate composition Pa6. The obtained one-part moisture-curable polyisocyanate composition has a viscosity of 90000 mPa s (25 ° C.), an NCO content of 10.0% by mass, an HDI monomer concentration of 0.50% by mass, an average NCO number of 4.4, and an allophanate structure. was 1.1% by mass.

[Example 7]
(Production of one-component moisture-curable polyisocyanate composition Pa7)
Polyisocyanate A-2: 30 g, polyisocyanate A-4: 70 g and polyether polyol (manufactured by AGC Co., Ltd., trade name "Exenol 1020", number average molecular weight 1000, number average of hydroxyl groups in the same apparatus as in Synthesis Example 1 Functional group number 2): 70 g was charged and urethanized with stirring at 120° C. for 6 hours to obtain a one-pack moisture-curable polyisocyanate composition Pa7. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 20000 mPa s (25 ° C.), an NCO content of 8.5% by mass, an HDI monomer concentration of 0.50% by mass, an average NCO number of 4.2, and an allophanate structure. was 40.2% by mass.

[Example 8]
(Production of one-component moisture-curable polyisocyanate composition Pa8)
500 g of HDI and 2 g of isobutyl alcohol were charged into the same apparatus as in Synthesis Example 1, and urethanization reaction was carried out at 80° C. for 1 hour while stirring. Tetramethylammonium caprate: 0.05 g was added as an allophanatization and isocyanuration catalyst to carry out an isocyanuration reaction. When the refractive index of the reaction solution reached 0.035, phosphoric acid was added to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain a one-component moisture-curable polyisocyanate composition Pa8. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 30000 mPa s (25 ° C.), an NCO content of 16.0% by mass, an HDI monomer concentration of 0.09% by mass, an average NCO number of 4.1, and an allophanate structure. was 4.1% by mass.

[Example 9]
(Production of one-component moisture-curable polyisocyanate composition Pa9)
500 g of HDI and 10 g of 1,3-butanediol (molecular weight: 90, number of hydroxyl groups: 2) were placed in the same apparatus as in Synthesis Example 1, and urethanization reaction was carried out at 80° C. for 1 hour while stirring. 0.05 g of isobutyl alcohol was added to tetramethylammonium caprate as an allophanatization and isocyanuration catalyst to carry out an isocyanuration reaction. When the refractive index of the reaction solution reached 0.025, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain a one-component moisture-curable polyisocyanate composition Pa9. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 25000 mPa s (25 ° C.), an NCO content of 19.2% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 4.3, and an allophanate structure. was 0.0% by mass.

[Example 10]
(Production of one-component moisture-curable polyisocyanate composition Pa10)
HDI: 500 g and polyester polyol (manufactured by DIC Corporation, trade name "Polylite OD-X-2733", number average molecular weight: 300, number average functional number of hydroxyl groups: 3): 30 g were charged into the same apparatus as in Synthesis Example 1. , and a urethanization reaction was carried out at 90° C. for 1 hour while stirring. Tetramethylammonium caprate: 0.05 g was added as an allophanatization and isocyanuration catalyst to carry out an isocyanuration reaction. When the refractive index of the reaction liquid increased to 0.023, phosphoric acid was added to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain a one-component moisture-curable polyisocyanate composition Pa10. The resulting one-component moisture-curable polyisocyanate composition has a viscosity of 35000 mPa s (25° C.), an NCO content of 18.8% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 5.0, and an allophanate structure. was 0.0% by mass.

[Example 11]
(Production of one-component moisture-curable polyisocyanate composition Pa11)
HDI: 500 g and polyether polyol (manufactured by AGC Co., Ltd., trade name "Exenol 410NE", number average molecular weight: 550, hydroxyl number average functionality: 4): 120 g were charged in the same apparatus as in Synthesis Example 1, and stirred. It was held at 120° C. for 5 hours. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain a one-component moisture-curable polyisocyanate composition Pa11. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 15000 mPa s (25 ° C.), an NCO content of 8.0% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 7.8, and an allophanate structure. was 0.0% by mass.

[Example 12]
(Production of one-component moisture-curable polyisocyanate composition Pa12)
In the same apparatus as in Synthesis Example 1, HDI: 400 g, IPDI: 100 g and polyester polyol (manufactured by DIC Corporation, trade name "Polylite OD-X-2733", number average molecular weight 300, number average functional group number of hydroxyl group 3): 30 g of this was charged, and a urethanization reaction was carried out at 90° C. for 1 hour while stirring. Tetramethylammonium caprate: 0.05 g was added as an allophanatization and isocyanuration catalyst to carry out an isocyanuration reaction. When the increase in the refractive index of the reaction solution reached 0.02, phosphoric acid was added to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain a one-component moisture-curable polyisocyanate composition Pa12. The resulting one-component moisture-curable polyisocyanate composition has a viscosity of 200000 mPa s (25° C.), an NCO content of 15.0% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 5.1, and an allophanate structure. was 0.0% by mass.

[Example 13]
(Production of one-component moisture-curable polyisocyanate composition Pa13)
500 g of HDI and 7 g of ethylene glycol (molecular weight: 62, number of hydroxyl groups: 2) were charged into the same apparatus as in Synthesis Example 1, and urethanization reaction was carried out at 80° C. for 1 hour while stirring. 0.05 g of isobutyl alcohol was added to tetramethylammonium caprate as an allophanatization and isocyanuration catalyst to carry out an isocyanuration reaction. When the refractive index of the reaction solution reached 0.025, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain a one-component moisture-curable polyisocyanate composition Pa13. The obtained one-part moisture-curable polyisocyanate composition has a viscosity of 24000 mPa s (25 ° C.), an NCO content of 20.5% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 4.2, and an allophanate structure. was 0.0% by mass.

[Comparative Example 1]
(Production of one-component moisture-curable polyisocyanate composition P-b1)
500 g of HDI and 2 g of isobutyl alcohol were charged into the same apparatus as in Synthesis Example 1, and urethanization reaction was carried out at 80° C. for 1 hour while stirring. 0.05 g of isobutyl alcohol was added to tetramethylammonium caprate as an allophanatization and isocyanuration catalyst to carry out an isocyanuration reaction. When the refractive index of the reaction solution reached 0.025, phosphoric acid was added to stop the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain a one-component moisture-curable polyisocyanate composition P-b1. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 6000 mPa s (25 ° C.), an NCO content of 18.8% by mass, an HDI monomer concentration of 0.09% by mass, an average NCO number of 3.6, and an allophanate structure. was 4.1% by mass.

[Comparative Example 2]
(Production of one-component moisture-curable polyisocyanate composition P-b2)
In the same apparatus as in Synthesis Example 1, polyisocyanate A-2: 100 g and polyether polyol (manufactured by AGC Co., Ltd., trade name "Exenol 1020", number average molecular weight 1000, number average functional number of hydroxyl groups 2): 50 g. After charging, a urethanization reaction was carried out at 120° C. for 6 hours while stirring to obtain a one-component moisture-curable polyisocyanate composition P-b2. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 9000 mPa s (25 ° C.), an NCO content of 12.5% by mass, an HDI monomer concentration of 0.50% by mass, an average NCO number of 3.5, and an allophanate structure. was 1.3% by mass.

[Comparative Example 3]
(Production of one-component moisture-curable polyisocyanate composition P-b3)
In the same apparatus as in Synthesis Example 1, 15 g of a nurate polyisocyanate derived from isophorone diisocyanate (manufactured by Eponic, trade name "VESTANAT (registered trademark) T1890"), 15 g of polyisocyanate B-1 and polyisocyanate A- 4: 50 g and polyether polyol (manufactured by AGC Co., Ltd., product name "Exenol 840", number average molecular weight 6500, number average functional group number of hydroxyl group 2): 20 g are charged, and urethanization reaction is performed at 120 ° C. for 6 hours while stirring. , to obtain a one-component moisture-curable polyisocyanate composition P-b3. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 3000 mPa s (25 ° C.), an NCO content of 14.0% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 2.5, and an allophanate structure. was 47.0% by mass.

[Comparative Example 4]
(Production of one-component moisture-curable polyisocyanate composition P-b4)
40 g of polyisocyanate B-2 and 60 g of polyisocyanate B-3 were placed in the same apparatus as in Synthesis Example 1 and mixed by stirring to obtain a one-component moisture-curable polyisocyanate composition P-b4. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 5000 mPa s (25 ° C.), an NCO content of 12.0% by mass, an HDI monomer concentration of 0.10% by mass, an average NCO number of 3.5, and an allophanate structure. was 0.0% by mass.

[Comparative Example 5]
(Production of one-component moisture-curable polyisocyanate composition P-b5)
In the same apparatus as in Synthesis Example 1, HDI: 500 g, 2-ethylhexanol: 50 g, and polyether polyol (manufactured by AGC Co., Ltd., trade name "Exenol 840", number average molecular weight 6500, number average functional group number of hydroxyl group 2): 47 g was charged, and 0.05 g of tetramethylammonium caprate was added as an isocyanurate-forming catalyst to carry out an isocyanurate-forming reaction. When the refractive index of the reaction liquid increased to 0.008, phosphoric acid was added to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain a one-component moisture-curable polyisocyanate composition P-b5. The obtained one-component moisture-curable polyisocyanate composition has a viscosity of 1000 mPa s (25 ° C.), an NCO content of 14.6% by mass, an HDI monomer concentration of 0.15% by mass, an average NCO number of 2.8, and an allophanate structure. was 30.0% by mass.

The physical properties of each one-component moisture-curable polyisocyanate composition obtained and the evaluation results of coating films using each one-component moisture-curable polyisocyanate composition are shown in Tables 1 to 3 below.
In Tables 1 to 3, each symbol indicates the following compounds.

(polyol)
PO-1: Polyether polyol (manufactured by AGC Co., Ltd., trade name "Exenol 1020", number average molecular weight 1000, number average functional number of hydroxyl groups 2)
PO-2: Polyester polyol (manufactured by DIC Corporation, trade name "Polylite OD-X-2155", number average molecular weight 1000, number average functional number of hydroxyl groups 2)
PO-3: Polycarbonate polyol (manufactured by Asahi Kasei Corporation, product name “Duranol T5651”, number average molecular weight 1000, number average functional number of hydroxyl groups 2)
PO-4: Polyether polyol (manufactured by AGC Co., Ltd., trade name "Exenol 2020", number average molecular weight 2000, number average functional number of hydroxyl groups 2)
PO-5: Polyether polyol (manufactured by AGC Co., Ltd., trade name "Exenol 3020", number average molecular weight 3200, number average functional number of hydroxyl groups 2)
PO-6: Polyether polyol (manufactured by Hodogaya Chemical Co., Ltd., trade name “PTG1000”, number average molecular weight 1000, number average functional group number of hydroxyl group 2)
PO-7: 1,3-butanediol (molecular weight 90, number of hydroxyl groups 2)
PO-8: Polyester polyol (manufactured by DIC Corporation, trade name “Polylite OD-X-2733”, number average molecular weight 300, number average functional number of hydroxyl groups 3)
PO-9: Polyether polyol (manufactured by AGC Co., Ltd., trade name “Exenol 410NE”, number average molecular weight 550, number average functional number of hydroxyl groups 4)
PO-10: ethylene glycol (molecular weight 62, number of hydroxyl groups 2)
PO-11: Polyether polyol (manufactured by AGC Co., Ltd., trade name “Exenol 840”, number average molecular weight 6500, number average functional number of hydroxyl groups 2)
PO-12: Polyether polyol (manufactured by Hodogaya Chemical Co., Ltd., trade name “PTG4000”, number average molecular weight 4000, number average functional group number of hydroxyl group 2)

(Moisture curing accelerating catalyst)
U-100: Trade name “Neostan U-100” (dibutyltin dilaurate) manufactured by Nitto Kasei Co., Ltd.
U-810: Trade name “Neostan U-810” (dioctyltin dilaurate) manufactured by Nitto Kasei Co., Ltd.

From Tables 1 and 2, it contains a polyisocyanate obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and the number average functionality of the isocyanate groups is within a specific range. The liquid and moisture-curable polyisocyanate compositions Pa1 to Pa13 (Examples 1 to 13) have excellent reactivity, and excellent hardness, initial solvent resistance, and surface smoothness when formed into a coating film. was
In addition, one-component moisture-curable polyisocyanate compositions Pa1 to Pa6 and Pa8 to Pa13 (Examples 1 to 6 and 8 to 13) were particularly excellent in reactivity.
Further, the one-component moisture-curable polyisocyanate composition Pa1, wherein the content of the allophanate structure is 0.0% by mass or more and 18.4% by mass or less, and the number average molecular weight of the polyol is 90 or more and 2000 or less. To Pa4, Pa6, and Pa8 to Pa13 (Examples 1 to 4, 6, and 8 to 13) had particularly excellent hardness when formed into coating films.
In addition, the content of the allophanate structure is 0.0% by mass or more and 18.4% by mass or less, and one-component moisture-curable polyisocyanate compositions Pa1 to Pa5 using a specific type of polyol, and Pa9 to Pa13 (Examples 1 to 5 and 9 to 13) were particularly excellent in initial solvent resistance when formed into coating films.
In addition, the number average molecular weight of the polyol is 90 or more and 3000 or less, and one-component moisture-curable polyisocyanate compositions Pa1 to Pa5, Pa7, and Pa9 using a specific type of polyol. ~Pa12 (Examples 1 to 5, 7, and 9 to 12) had particularly excellent surface smoothness when formed into a coating film.

On the other hand, from Table 3, the one-component moisture-curable polyisocyanate compositions P-b1 to P-b5 (Comparative Examples 1 to 5), in which the number-average number of isocyanate groups is less than 4.1, were evaluated as "A". None were excellent in reactivity, hardness, initial solvent resistance, and surface smoothness.

According to the one-component moisture-curable polyisocyanate composition of the present embodiment, a one-component moisture-curable polyisocyanate having excellent reactivity and excellent hardness, initial solvent resistance, and surface smoothness when formed into a coating film. A composition can be provided. The one-part moisture-curable polyisocyanate composition of the present embodiment can be used as a raw material for paints, inks, adhesives, casting materials, elastomers, foams, and plastic materials. The one-component moisture-curable coating composition of the present embodiment contains the one-component moisture-curable polyisocyanate composition, and is used in construction paints, heavy-duty anti-corrosion paints, automotive paints, information appliance paints, personal computers, mobile phones, etc. It is suitable for paints for information equipment.

Claims (9)

A polyisocyanate obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates,
A one-component moisture-curable polyisocyanate composition having an isocyanate group having a number average functionality of 4.1 or more and 8.0 or less. 2. The one-part moisture-curable polyisocyanate composition according to claim 1, wherein the content of the allophanate structure derived from a monoalcohol is 35.0% by mass or less relative to the mass of the polyisocyanate. 3. The one-component moisture-curable polyisocyanate composition according to claim 1, wherein the polyisocyanate has a structural unit derived from a polyol having a hydroxyl group number average functionality of 2 or more. 4. The one-component moisture-curable polyisocyanate composition according to claim 3, wherein the polyol is at least one polyol selected from the group consisting of aliphatic diols, polyether polyols, polyester polyols, and polycarbonate polyols. 5. The one-part moisture-curable polyisocyanate composition according to claim 3 or 4, wherein the polyol has a number average molecular weight of 80 or more and 2500 or less. The one-component moisture-curable polyisocyanate composition according to any one of claims 1 to 5, wherein the one-component moisture-curable polyisocyanate composition has a viscosity of 5000 mPa·s or more. A one-component moisture-curable coating composition comprising the one-component moisture-curable polyisocyanate composition according to any one of claims 1 to 6 and a moisture-curing accelerating catalyst. 8. The one-component moisture-curable paint according to claim 7, which is used as a top clear paint for building structures, automobile bodies, automobile metal parts, automobile plastic parts, information home appliance metal parts, or information home appliance plastic parts. Composition. A coating film obtained by curing the one-component moisture-curable coating composition according to claim 7 or 8.