JP7409757B1 - High solids coating composition - Google Patents

Abstract

[Problem] To provide a high solid content coating composition that has excellent weather resistance, corrosion resistance, and coating hardness and can be directly coated on metal materials. [Solution] A polyaspartic acid ester (A), a polyisocyanate compound (B), an epoxy group-containing silane coupling agent (C), and a weight average molecular weight of 250 to 2300 and a hydroxyl value within the range of 50 to 800. A high solids coating composition containing a certain polyol (D). In particular, a high solid content coating composition having a solid content concentration of 70% by mass or more. A coating method for coating an object to be coated with the high solids coating composition, and a construction machine or industrial machine coated with the high solids coating composition. [Selection diagram] None

Description

The present invention relates to a high solid content coating composition that has excellent weather resistance and corrosion resistance and can be directly coated on metal materials.

Conventionally, acrylic lacquer, acrylic urethane paint, aminoacrylic resin paint, etc. have been used to paint industrial machinery, buildings, automobiles, structures, furniture (including steel), etc., and in particular, bulldozers, hydraulic excavators, wheels, etc. In painting construction machinery or industrial machinery such as loaders, acrylic urethane paints containing hydroxyl group-containing acrylic resins and polyisocyanate compounds are mainly used from the viewpoint of room temperature drying properties and durability.

In addition, in recent years, there has been a need to reduce volatile organic compounds (VOCs) in paints, both from an ESG perspective and due to their impact on the environment, and VOC regulations, including legislation, are being strengthened worldwide. ing.

For construction machinery, etc., paint compositions of acrylic resin and isocyanate compounds have been used in one-coat specifications that are directly applied to metal materials to ensure weather resistance and corrosion resistance. There were limits to VOC reduction.

In general, coating compositions made of polyamine compounds and isocyanate compounds have excellent coating film performance such as high corrosion resistance and chemical resistance. Because it is difficult to handle, it has not been put into practical use as a coating for construction machinery, etc.

Patent Document 1 discloses that a base polyol containing a low molecular weight acrylic polyol or a polyester polyol, an aliphatic diisocyanate, and an alicyclic diisocyanate are used as raw materials, and the content of components with a molecular weight of 700 or less is 20 to 60% by mass, weight average The ratio between the molecular weight and the number average molecular weight is 1.2 to 5.0, and the ratio between the viscosity (unit: mPa.s) of the polyisocyanate composition at 25°C and the number average number of functional groups of the isocyanate groups is expressed by a specific formula. A high solids coating composition characterized in that it uses a polyisocyanate composition is disclosed.

However, the high solid coating composition described in Patent Document 1 is insufficient to satisfy the VOC regulation level that has been strengthened in recent years, and the coating workability may be insufficient.

Patent Document 2 discloses a polyaspartate-based coating composition with a significantly reduced dialkyl fumarate content as a coating composition for producing a gloss-stable colored top coat.

However, the coating composition described in Patent Document 2 may have insufficient corrosion resistance and weather resistance, or may have insufficient adhesion to metal materials, which is particularly required when directly coating metal materials. Ta.

Japanese Patent Application Publication No. 2003-128989 Special Publication No. 2022-521250

The problem to be solved by the present invention is to provide a high solid content coating composition that has excellent weather resistance, corrosion resistance, and coating hardness, and can be directly coated on metal materials.

As a result of intensive studies, the present inventors have found that polyaspartic acid ester (A), polyisocyanate compound (B), epoxy group-containing silane coupling agent (C), and polyol having a weight average molecular weight and hydroxyl value within a specific range. The inventors have discovered that the above-mentioned problems can be solved by using a high-solids coating composition containing (D), and have completed the present invention.

That is, the present invention
1. A polyaspartic acid ester (A), a polyisocyanate compound (B), an epoxy group-containing silane coupling agent (C), and a polyol (D) having a weight average molecular weight of 250 to 2300 and a hydroxyl value within the range of 50 to 800. ) A high solids coating composition containing.

2. The high solid content coating composition according to item 1 above, wherein the polyaspartic acid ester (A) contains a polyaspartic acid ester having a secondary amino group represented by the following formula (1).

⁽ wherein ^, It is an organic group that is inert to isocyanate groups, and n is an integer of 2 or more.)
3. 3. The high solids coating composition according to item 1 or 2 above, wherein the polyol (D) contains a polyester polyol and/or a polyether polyol.

4. The high solid content coating composition according to any one of items 1 to 3 above, which has a solid content concentration of 70% by mass or more.

5. The high solid content coating composition according to any one of items 1 to 4 above, further containing a pigment.

6. The high solid content coating composition according to any one of items 1 to 5 above, wherein the polyisocyanate compound (B) contains a silyl group-containing modified polyisocyanate.

7. Item 6 above, wherein the silyl group-containing modified polyisocyanate is a reaction product using as raw materials a component containing an alkoxysilane (a1) having a primary amino group, a carboxylic acid alkyl ester (a2), and a polyisocyanate (a3). The high solids coating composition described in .

8. The high solid content coating composition according to any one of items 1 to 7 above, further containing zeolite.

9. The one-coat high solid content coating composition according to any one of items 1 to 8 above.

10. A coating method of coating an object to be coated with the high solid content coating composition according to any one of items 1 to 8 above.

11. The present invention relates to construction machinery or industrial machinery coated with the high solid content coating composition according to any one of items 1 to 8 above.

The coating composition of the present invention has a polyaspartic acid ester, a polyisocyanate compound, an epoxy group-containing silane coupling agent, and a polyol with a low molecular weight and high hydroxyl value as constituent components, so it has a low viscosity and has a VOC reduction effect. The resulting urea crosslinked coating has excellent weather resistance and corrosion resistance.

In addition, metal adhesion is improved by improving the barrier properties with the epoxy group-containing silane coupling agent, and the level of weather resistance, corrosion resistance, and coating film hardness is further improved by improving the crosslinking density with the low molecular weight polyol. It is presumed that there is.

Therefore, the coating composition of the present invention has excellent weather resistance, corrosion resistance, and coating hardness, and has high metal adhesion, so it can be directly coated on metal materials, and it also has a high finish with excellent appearance. It is possible to achieve the effect that a solid content coating composition can be obtained.

The high solid content coating composition of the present invention (hereinafter sometimes simply abbreviated as the present coating) comprises a polyaspartic acid ester (A), a polyisocyanate compound (B), and an epoxy group-containing silane coupling agent (C). , and a polyol (D). This will be described in detail below.

<Polyaspartic acid ester (A)>
As the polyaspartic acid ester, a polyaspartic acid ester having a secondary amino group is preferable from the viewpoint of reactivity and coating workability.

Specifically, the following formula (1)

⁽ wherein ^, It is an organic group that is inert to isocyanate groups, and n is an integer of 2 or more.

In formula (1), X is an n-valent cyclic or chain aliphatic hydrocarbon group or a polyoxyalkylene polyamine residue having a number average molecular weight of 25 to 5,000.

X is an n-valent group having a number average molecular weight of 25 to 5,000, preferably 50 to 3,000, more preferably 100 to 2,000.

X is an aliphatic hydrocarbon group or a polyoxyalkylene polyamine residue.

The aliphatic hydrocarbon group may be an alicyclic hydrocarbon group, a chain hydrocarbon group, or a group having both an alicyclic part and a chain part. .

The alicyclic hydrocarbon group may have a side chain. The chain hydrocarbon group may be a straight chain hydrocarbon group or a branched hydrocarbon group.

X is preferably a divalent aliphatic hydrocarbon group. Examples of the divalent aliphatic hydrocarbon group include alkylene, cycloalkylene, cycloalkylalkylene, alkylcycloalkylene, alkylenebiscycloalkylene, alkylenebis(alkylcycloalkylene), and cycloalkylenebisalkylene.

Here, alkylene is preferably alkylene having 1 to 8 carbon atoms, cycloalkylene is preferably cycloalkylene having 5 to 6 carbon atoms, alkyl is preferably alkyl having 1 to 8 carbon atoms, and cycloalkyl is preferably alkylene having 1 to 8 carbon atoms. Preferred is cycloalkyl having 5 to 6 carbon atoms.

The polyoxyalkylene polyamine residue refers to a group obtained by removing the primary amino groups at both ends from a polyoxyalkylene polyamine. The polyoxyalkylene polyamine residue may have a side chain. The polyoxyalkylene polyamine residue is preferably a polyoxyethylene polyamine residue, a polyoxypropylene polyamine residue, a polyoxybutylene polyamine residue, or a polyoxyethylene polyoxypropylene polyamine residue. The polyoxyalkylene polyamine residue is more preferably -(CH(CH ₃ )-CH ₂ -O)x-CH ₂ -CH(CH ₃ )- (where x is an integer from 3 to 6). It is.

In formula (1), R ¹ and R ² are each independently an organic group inert to isocyanate groups. R ¹ and R ² are preferably alkyl having 1 to 15 carbon atoms, more preferably alkyl having 1 to 8 carbon atoms, still more preferably methyl or ethyl, and most preferably ethyl.

In formula (1), n is an integer of 2 or more. n is preferably an integer of 2 to 6, more preferably an integer of 2 to 4, and most preferably 2.

The compound represented by formula (1) can be synthesized, for example, by reacting an optionally substituted maleate or fumarate with a polyamine.

Specific examples of the compound represented by formula (1) include, but are not limited to, tetraethyl N,N'-[methylenebis(cyclohexane-4,1-diyl)]bisaspartate, N,N'-( Tetraethyl hexane-1,6-diyl)bisaspartate, N,N'-(2-methylpentane-1,5-diyl)tetrabutylbisaspartate, N,N'-[methylenebis(3-methylcyclohexane-4, 1-diyl)]bisaspartate tetraethyl, N,N'-(bis-2-propyl)polypropylene glycol 300-O,O'-diylbisaspartate tetraethyl, N,N'-(butane-1,4-diyl) ) bistetraethyl aspartate, N,N'-(2,2-dimethylpropane-1,3-diyl)bistetraethyl aspartate, N,N'-(2,4-dimethylhexane-1,6-diyl)bis At least one member selected from the group consisting of tetraethyl aspartate and mixtures thereof can be mentioned. Among them, N,N′-[methylenebis(cyclohexane-4,1-diyl)]bisaspartate tetraethyl, N,N′-(2-methylpentane-1,5-diyl)bisaspartate tetrabutyl, N,N Tetraethyl'-[methylenebis(3-methylcyclohexane-4,1-diyl)]bisaspartate is preferred.

Commercially available products of polyaspartic acid ester (A) include "Desmophen NH1420", "Desmophen NH1423LF", "Desmophen NH 1520", and "Desmophen NH 1220" (above, Examples include "FEISOARTIC F420", "FEISOARTIC F220", and "FEISOARTIC F520" (all trade names, manufactured by Feiyang).

<Polyisocyanate compound (B)>
As the polyisocyanate compound, those conventionally used in polyurethane production can be used.

Specific examples of the polyisocyanate compound include aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, araliphatic polyisocyanate compounds, aromatic polyisocyanate compounds and their crude products, and modified products of these polyisocyanate compounds. etc. can be mentioned.

Examples of modified products include biuret modified products, isocyanurate modified products, and mixtures of two or more thereof.

Among the above, aliphatic polyisocyanate compounds can be preferably used from the viewpoint of high solid content.

The aliphatic polyisocyanate compound is a compound having a linear or branched chain carbon skeleton and having two or more free isocyanate groups in one molecule.

Specific examples of aliphatic polyisocyanate compounds include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, Lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl) fumarate, bis(2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate etc. can be mentioned.

Specific examples of modified aliphatic polyisocyanate compounds include biuret-modified HDI, isocyanurate-modified HDI, and the like.

As the aliphatic polyisocyanate compound, from the viewpoint of curability and finished appearance, hexamethylene diisocyanate (HDI) and modified products of HDI can be suitably used.

Commercially available products of the aliphatic polyisocyanate compound (B) include, for example, TUL-100 (manufactured by Asahi Kasei Chemicals), Desmodur N3900 (manufactured by Sumika Covestro Urethane Co., Ltd.), and Desmodur N3600 (manufactured by Sumika Covestro Urethane Co., Ltd.). ), Desmodur N3200 (manufactured by Sumika Covestrourethane), TOLONATE XF-800 (manufactured by Vencolex), TOLONATE XF-450 (manufactured by Vencolex), and the like.

Specific examples of the alicyclic polyisocyanate compounds include isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis( Examples include 2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate, 2,5- and/or 2,6-norbornane diisocyanate, and the like.

Specific examples of the above-mentioned araliphatic polyisocyanate compounds include m- and/or p-xylylene diisocyanate (XDI), α, α, α', α'-tetramethylxylylene diisocyanate (TMXDI), etc. can.

Specific examples of the aromatic polyisocyanate compound include 1,3- and/or 1,4-phenylene diisocyanate, 2,4- and/or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4-phenylene diisocyanate, '- and/or 4,4'-biphenylmethane diisocyanate (MDI), 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl -4,4'-diisocyanatodiphenylmethane, crude MDI, 1,5-naphthylene diisocyanate, 4,4',4''-triphenylmethane triisocyanate, m- and p-isocyanatophenylsulfonyl isocyanate, etc. be able to.

In addition, examples of modified polyisocyanate compounds other than the aliphatic polyisocyanate compounds mentioned above include modified MDI (urethane-modified MDI, carbodiimide-modified MDI, trihydrocarbyl phosphate-modified MDI), urethane-modified TDI, and isocyanurate-modified IPDI. modified polyisocyanate compounds; and mixtures of two or more thereof [for example, a mixture of modified MDI and urethane modified TDI].

Furthermore, as a modified polyisocyanate compound, a silyl group-containing modified polyisocyanate can be used for the purpose of improving corrosion resistance.

The silyl group-containing modified polyisocyanate can further improve the corrosion resistance of the resulting coating film without reducing its gloss.

The silyl group-containing modified polyisocyanate is not particularly limited, and any modified polyisocyanate containing a silyl group can be used without restriction, but in particular, alkoxysilane (a1) having a primary amino group, carbon Silyl group-containing modified polyisocyanate (X), which is a reaction product made from components containing acid alkyl ester (a2) and polyisocyanate (a3) as raw materials, can be suitably used.

Silyl group-containing modified polyisocyanate (X) is a modified polyisocyanate that is synthesized using carboxylic acid alkyl ester (a2) as a modifier, can be stably diluted in an organic solvent, and has excellent storage stability.

Specific examples of compound (a1) include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyl-methyldiethoxysilane, 3-aminopropyl-methyldimethoxysilane, and 3-aminopropyl-ethylene. Examples include glycoloxymethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, 4-amino-3,3-dimethylbutyltriethoxysilane, and combinations thereof. Particularly preferred are 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

The carboxylic acid alkyl ester (a2) is preferably a saturated carboxylic acid alkyl ester.

Specific examples of saturated carboxylic acid alkyl esters include methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, n-pentyl acetate, i-pentyl acetate, cyclohexyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, 1-methylpentyl acetate (also known as sec-hexyl acetate), 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 3-methoxybutyl acetate, 3-ethoxybutyl acetate, propionic acid Methyl, ethyl propionate, n-propyl propionate, i-propyl propionate, n-butyl propionate, i-butyl propionate, n-pentyl propionate, i-pentyl propionate, methyl butyrate, ethyl butyrate, n butyrate -propyl, i-propyl butyrate, n-butyl butyrate, i-butyl butyrate, t-butyl butyrate, methyl valerate, ethyl valerate, methyl octoate, methyl laurate, methoxypropyl acetate, ethyl 3-ethoxypropionate, Butyl glycol acetate, butyl diglycol acetate, methyl isovalerate, ethyl isovalerate, methyl 3,3,5-trimethylhexanoate, methyl isobutyrate, ethyl isobutyrate, i-butyl isobutyrate, n-butyl i-butyrate , t-butyl i-butyrate, methyl 2-ethylhexanoate, methyl pivalate, ethyl 2-hydroxy-2-methylpropionate, methyl neodecanoate, di-i-propyl fumarate, isobornyl acrylate, and combinations thereof.

Examples of the polyisocyanate (a3) include the polyisocyanate compounds described in the above polyisocyanate compound (B).

The method for producing the silyl group-containing modified polyisocyanate (X) may be a method in which an alkoxysilane having a primary amino group (a1), a carboxylic acid alkyl ester (a2), and a polyisocyanate (a3) are simultaneously reacted. Preferably, the alkoxysilane (a1) and the carboxylic acid alkyl ester (a2) are reacted in advance to obtain an N-position modified alkoxysilane having a secondary amino group or a secondary amide group, which is further reacted with the polyisocyanate (a3). Preferably, the production method involves reacting with.

From the viewpoint of corrosion resistance, drying properties, etc., the amount of isocyanate groups in the silyl group-containing modified polyisocyanate is, for example, 1.0 mmol or more, 2.0 mmol or more, 5.5 mmol or less, 5. It is preferably within the range of 0 mmol or less.

The amount of isocyanate groups in a modified polyisocyanate can be determined, for example, by adding 10 ml of a 0.1 mol/L dibutylamine solution to 0.1 g of a sample, reacting the NCO groups, using bromophenol blue as a titration indicator, and removing the remaining dibutyl amine with an aqueous hydrochloric acid solution. It can be determined by titration.

The polyisocyanate compound (B) can be used alone or in combination of two or more.

From the viewpoint of curability and dryness to the touch, the ratio of the amino groups of the polyaspartic acid ester (A) to the isocyanate groups of the polyisocyanate compound (B) is such that the isocyanate groups are 0.00 to 1 equivalent of the amino group. It is preferably within the range of 5 to 2.0 equivalents, particularly 0.8 to 1.5 equivalents, and even more particularly 1.0 to 1.3 equivalents.

In addition, from the viewpoint of corrosion resistance and weather resistance, the polyaspartic acid ester (A) is 20 to 70% by mass, especially 30 to 70% by mass, based on the total solid content of the polyaspartic acid ester (A) and the polyisocyanate compound (B). It is preferable that the amount of the polyisocyanate compound (B) is in the range of 30 to 80% by weight, particularly 50 to 70% by weight.

In addition, when a silyl group-containing modified polyisocyanate is contained as the polyisocyanate compound (B), the solid content of the silyl group-containing modified polyisocyanate is determined by the solid content of the polyisocyanate compound (B) from the viewpoint of corrosion resistance and dryness to the touch. It is preferably within the range of 1 to 100% by weight, particularly 5 to 70% by weight, and even more particularly 5 to 50% by weight, based on the total amount.

<Epoxy group-containing silane coupling agent (C)>
In the present invention, the epoxy group-containing silane coupling agent (C) is a component that particularly contributes to improving the corrosion resistance of the coating composition of the present invention by improving adhesion to metal materials.

The epoxy group-containing silane coupling agent (C) is a compound having both an alkoxysilyl group and an epoxy group in its molecule, and specific examples include glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, , β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyl(methyl)dimethoxysilane, γ-glycidoxypropyl ( Examples include dimethyl)methoxysilane, γ-glycidoxypropyl(ethyl)dimethoxysilane, (3,4-epoxycyclohexyl)methyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc. .

As the epoxy group-containing silane coupling agent (C), γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropylmethyldiethoxysilane can be preferably used from the viewpoint of corrosion resistance and finished appearance.

The epoxy equivalent of the epoxy group-containing silane coupling agent (C) is preferably in the range of 100 to 1000 g/eq, particularly 100 to 500 g/eq, from the viewpoint of coating film appearance.

The epoxy group-containing silane coupling agent (C) can be used alone or in combination of two or more.

In the coating composition of the present invention, from the viewpoint of water resistance and coating film appearance, the amount of the epoxy group-containing silane coupling agent (C) is determined by the total solid content of the polyaspartic acid ester (A) and the polyisocyanate compound (B). It is preferably 0.1 to 50% by weight, particularly 0.5 to 30% by weight, and even more particularly 0.5 to 15% by weight.

<Polyol (D)>
Specific examples of the polyol (D) include polyester polyols, polyether polyols, acrylic polyols, polyolefin polyols, fluorine polyols, polycarbonate polyols, and polyurethane polyols. The polyol (D) may contain one type alone or a combination of two or more types.

Among these, polyether polyol and polyether polyol are preferred as the polyol (D) from the viewpoint of dryness to the touch and weather resistance.

1. Polyester Polyol Polyester polyol can be obtained, for example, by subjecting a dibasic acid and a polyhydric alcohol to a condensation reaction.

Examples of the dibasic acid include carboxylic acids such as succinic acid, adipic 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.

Other examples of polyester polyols that can be used include polycaprolactones obtained by ring-opening polymerization of lactones such as ε-caprolactone using polyhydric alcohols.

Moreover, alcohol components other than the above-mentioned polyhydric alcohols can also be used.

Specifically, for example, monoalcohols such as methanol, ethanol, propyl alcohol, butyl alcohol, stearyl alcohol, and 2-phenoxyethanol; propylene oxide, butylene oxide, neodecanoic acid glycidyl ester (commercially available products include "Cardura E10P" (trade name) Alcohol compounds obtained by reacting monoepoxy compounds such as glycidyl esters of synthetic highly branched saturated fatty acids (manufactured by HEXION) with acids; esterified products of glycol and monobasic acids, and the like.

2. Polyether Polyols Polyether polyols are not particularly limited, but include, for example, those shown in (1) to (3) below.

(1) Polyether polyols obtained by random or block addition of an alkylene oxide alone or a mixture to a polyhydric hydroxy compound or a mixture using a catalyst.

Examples of the catalyst include hydroxides (lithium, sodium, potassium, etc.), strong basic catalysts (alcolate, alkylamine, etc.), complex metal cyanide compounds (metal porphyrin, zinc hexacyanocobaltate complex, etc.), and the like. be able to.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide.

(2) Polyether polyols obtained by reacting a polyamine compound with an alkylene oxide.

Examples of the polyamine compound include ethylenediamines.

Examples of the alkylene oxide include those exemplified in (1).

(3) So-called polymer polyols obtained by polymerizing acrylamide or the like using the polyether polyols obtained in (1) or (2) as a medium.

Examples of the polyvalent hydroxy compound include those shown in (i) to (vi) below.

(i) Diglycerin, ditrimethylolpropane, pentaerythritol, dipentaerythritol, etc.

(ii) Sugar alcohol compounds such as erythritol, D-threitol, L-arabinitol, ribitol, xylitol, sorbitol, mannitol, galactitol, rhamnitol and the like.

(iii) Monosaccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, ribodesose and the like.

(iv) Disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, and melibiose.

(v) Trisaccharides such as raffinose, gentianose, and meletitose.

(vi) Tetrasaccharides such as stachyose.

3. Acrylic polyol Acrylic polyols are not particularly limited, but include, for example, an ethylenically unsaturated bond-containing monomer having a hydroxy group alone or in a mixture, and other ethylenically unsaturated bond-containing monomers copolymerizable with this. Examples include those obtained by copolymerizing either alone or a mixture of the following.

The ethylenically unsaturated bond-containing monomer having a hydroxy group is not particularly limited, but includes, for example, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and methacryl. Examples include hydroxybutyl acid. These may be used alone or in combination of two or more. Among these, hydroxyethyl acrylate or hydroxyethyl methacrylate is preferred.

Other ethylenically unsaturated bond-containing monomers that can be copolymerized with the above monomers include, for example, those shown in (1) to (6) below. These may be used alone or in combination of two or more.

(1) Methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, acrylic acid Acrylic acid esters such as lauryl, benzyl acrylate, and phenyl acrylate.

(2) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Methacrylic acid esters such as lauryl, benzyl methacrylate, and phenyl methacrylate.

(3) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid.

(4) Unsaturated amides such as acrylamide, methacrylamide, N,N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, maleic acid amide, and maleimide.

(5) Vinyl monomers such as glycidyl methacrylate, styrene, vinyltoluene, vinyl acetate, acrylonitrile, and dibutyl fumarate.

(6) Vinyl monomers having a hydrolyzable silyl group such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, and γ-(meth)acryloxypropyltrimethoxysilane.

4. Polyolefin Polyol Polyolefin polyols are not particularly limited, but include, for example, polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, and the like.

5. Fluorine Polyol As used herein, fluorine polyol means a polyol containing fluorine in the molecule. Specifically, examples of fluorine polyols include fluoroolefins, cyclovinyl ethers, and hydroxyl which are disclosed in JP-A-57-34107 (Reference 1), JP-A-61-275311 (Reference 2), etc. Examples include copolymers of alkyl vinyl ethers and monocarboxylic acid vinyl esters.

Note that from the viewpoint of ESG, it is preferable not to use fluorine polyol.

6. Polycarbonate polyol The polycarbonate polyol is not particularly limited, but examples include those shown in (1) to (4) below.

(1) Dialkyl carbonate such as dimethyl carbonate;
(2) Alkylene carbonate such as ethylene carbonate;
(3) Diaryl carbonate such as diphenyl carbonate;
(4) Those obtained by condensation polymerization of low-molecular carbonate compounds such as those in (1) to (3) above.

7. Polyurethane polyol The polyurethane polyol is not particularly limited, but can be obtained, for example, by reacting a polyol and an isocyanate component by a conventional method.

Examples of the polyol include low molecular weight polyols such as ethylene glycol and propylene glycol. Furthermore, examples of high molecular weight polyols include acrylic polyols, polyester polyols, and polyether polyols.

The hydroxyl value of the polyol (D) is preferably in the range of 50 to 800, particularly 100 to 700, and more particularly 150 to 600, from the viewpoint of drying properties, crosslinking density and weather resistance.

In addition, in this invention, a hydroxyl value can be measured based on JISK1557.

The weight average molecular weight of the polyol (D) is preferably in the range of 250 to 2,300, particularly 250 to 1,500, and more particularly 250 to 1,000 from the viewpoints of drying properties, crosslinking density and weather resistance.

In the present invention, the "weight average molecular weight" is a value calculated based on the molecular weight of standard polystyrene from a chromatogram measured by gel permeation chromatography according to the method described in JIS K 0124-2011.

As a gel permeation chromatograph, "HLC8120GPC" (manufactured by Tosoh Corporation) was used. Four columns were used: "TSKgel G-4000HXL", "TSKgel G-3000HXL", "TSKgel G-2500HXL", and "TSKgel G-2000HXL" (all manufactured by Tosoh Corporation, trade names), and mobile phase: tetrahydrofuran. Measurement temperature: 40° C., flow rate: 1 ml/min, detector: RI.

In the coating composition of the present invention, from the viewpoint of drying property and crosslinking density, the amount of polyol (D) is 1 to 20% based on the total solid content of polyaspartic acid ester (A) and polyisocyanate compound (B). It is preferably % by weight, especially 1 to 10% by weight, more particularly 3 to 10% by weight.

In the coating composition of the present invention, the molar ratio of the hydroxyl groups of the polyol (D) to the isocyanate groups of the polyisocyanate composition (B) (hydroxyl groups/isocyanate groups) is 0.5 to 2.0 equivalents, particularly 0.8 to 2.0 equivalents. It is preferred that the amount is 1.5 equivalents, more particularly within the range of 1.0 to 1.3.

It is presumed that the polyol (D) improves the crosslinking density and particularly improves the weather resistance of the coating film.

The coating composition of the present invention may contain a curing catalyst as necessary for the purpose of promoting the reaction between the polyisocyanate compound (B) and the polyol (D). Examples of the curing catalyst include known urethane curing catalysts such as organometallic compounds, tertiary amines, and phosphoric acid compounds.

Examples of organometallic compounds include tin octylate, dibutyltin di(2-ethylhexanoate), dioctyltin di(2-ethylhexanoate), dioctyltin diacetate, dibutyltin dilaurate, dibutyltin oxide, and dioctyltin diacetate. Tin oxide, dibutyltin fatty acid salts, lead 2-ethylhexanoate, zinc octylate, zinc naphthenate, zinc fatty acids, cobalt naphthenate, calcium octylate, copper naphthenate, tetra(2-ethylhexyl) titanate may be mentioned. can.

The above curing catalysts can be used alone or in combination of two or more.

Coloring pigments can be used in the coating composition of the present invention for the purpose of providing a desired color. Specific examples of coloring pigments include titanium white, zinc molybdate, calcium molybdate, carbon black, graphite, iron black, navy blue, ultramarine blue, cobalt blue, copper phthalocyanine blue, and indanthrone. Blue, yellow lead, synthetic yellow iron oxide, red iron oxide, clear red iron oxide, bismuth vanadate, titanium yellow, zinc yellow, monoazo yellow, ocher, disazo, isoindolinone yellow, metal complex azo yellow, quinophthalone yellow, benzimidazo Ron yellow, monoazo red, unsubstituted quinacridone red, azo lake (Mn salt), quinacridone magenta, anthanthrone orange, dianthraquinonyl red, perylene maroon, perylene red, diketopyrrolopyrrole chrome vermilion, chlorinated phthalocyanine green, bromine Examples include phthalocyanine green, pyrazolone orange, benzimidazolone orange, dioxazine violet, and perylene violet.

When a colored pigment is used in the coating composition of the present invention, the amount used is 5 to 100% by mass, particularly 10 to 100% by mass, based on the total solid content of the polyaspartic acid ester (A) and the polyisocyanate compound (B). The content is preferably 60% by mass from the viewpoints of coating film appearance, weather resistance, and base hiding properties.

The coating composition of the present invention may contain an extender pigment if necessary.

Examples of the extender pigment include clay, silica, barium sulfate, talc, calcium carbonate, white carbon, diatomaceous earth, and magnesium carbonate.

In the above-mentioned extender pigment, barium sulfate or Calcium carbonate can be preferably used.

Commercial products of such extender pigments include barium sulfate such as Varifine BF-20 (manufactured by Sakai Chemical Industry Co., Ltd., trade name, barium sulfate with an average particle size of 0.03 μm), Variace B-33 (Sakai Chemical Co., Ltd., trade name, barium sulfate with an average particle size of 0.03 μm) (manufactured by Kogyo Co., Ltd., trade name, barium sulfate with an average particle diameter of 0.3 μm), SPARWITE W-5HB (manufactured by Sino-Can Co., Ltd., trade name, barium sulfate powder, average particle diameter: 1.6 μm), BLANC FIXE MICRO (manufactured by Venator Materials, trade name, barium sulfate with an average particle size of 0.7 μm),
Examples of calcium carbonate include Neolite SA-200 (manufactured by Takehara Chemical Industry Co., Ltd., trade name, calcium carbonate with an average particle diameter of 0.08 μm), Micro POWDER 3N (manufactured by Bihoku Funka Kogyo Co., Ltd., trade name, average particle diameter of 1.0 μm). 1 μm of calcium carbonate), Sunlight SL1500 (manufactured by Takehara Chemical Industry Co., Ltd., trade name, calcium carbonate of average particle size of 2.5 μm), and the like.

Note that in this specification, the average particle diameter is a value obtained by particle size distribution measurement using a dynamic light scattering method.

Specifically, it is a value measured using, for example, UPA-EX250 (trade name, manufactured by Nikkiso Co., Ltd., a particle size distribution measuring device using a dynamic light scattering method).

When an extender pigment is used in the coating composition of the present invention, the amount used is 10 to 200% by mass, particularly 15 to 200% by mass, based on the total solid content of the polyaspartic acid ester (A) and the polyisocyanate compound (B). The content is preferably 150% by mass from the viewpoint of finished appearance and painting workability.

In addition, in the coating composition of the present invention, the amount of pigments (coloring pigments, extender pigments, and other pigments) to be used is determined from the viewpoint of finished appearance and painting workability, and the amount of pigments (coloring pigments, extender pigments, and other pigments) ) is preferably within the range of 5 to 250% by weight, particularly 20 to 200% by weight, and even more particularly 25 to 150% by weight.

Zeolite can be further used in the coating composition of the present invention for the purpose of improving pot life.

Zeolite is a general term for crystalline aluminosilicates, and its constituent elements are Al, Si, O, and cations, and it has a tetrahedral structure formed from SiO ₄ and AlO ₄ (centered on Si ⁴⁺ or Al ³⁺ ). It is a compound whose basic structure is a tetrahedron formed. By connecting them in a complex and regular manner, pores with diameters of several angstroms to several tens of angstroms, approximately the same size as small molecules, are regularly formed in one, two, or three dimensions. This is a characteristic of zeolite.

Cations exist within the pores of zeolite, and the various functions of zeolite are expressed based on the cations. Some zeolites are called molecular sieves because only molecules smaller than their diameter can enter the pores of zeolites and can be screened out from larger molecules.

Zeolites include natural zeolites _{whose main} components are hydrated aluminosilicate and synthetic zeolites _{whose main} components are _{Na2O.Al2O3.xSiO2.yH2O} . Synthetic zeolites, also called palmchit, are produced by a dry method by eutecticizing sodium carbonate, silica, alumina or kaolin, or by a wet method by combining sodium silicate and sodium aluminate to precipitate a gel.

Both natural zeolite and synthetic zeolite have ion exchange ability, their crystal structure does not change even after dehydration, molecular-sized pores are obtained after dehydration, and they have large adsorption capacity. Moreover, a product in which pores of a certain size are obtained after crystallizing and dehydrating sodium aluminosilicate gel by hydrothermal synthesis is generally called a molecular sieve.

As the zeolite, from the viewpoint of pot life and corrosion resistance, what is generally called a molecular sieve can be suitably used. Zeolite molded into powder or pellet form is commercially available, and depending on the type of zeolite used as the raw material, Molecular Sieve 3A, Molecular Sieve 4A, Molecular Sieve 5A, Molecular Sieve 13X, etc. are commercially available. The numbers represent the approximate diameters (angstroms) of the pores, and the capital letters represent the type of zeolite, with A representing LTA type zeolite and X representing FAU type zeolite.

Among the above molecular sieves, from the viewpoint of finished appearance, molecular sieve 3A, molecular sieve 4A, and molecular sieve 5A are preferable, and molecular sieve 5A can be particularly preferably used.

The effective diameter of the pores changes depending on the position and size of the metal cations near the pores of the molecular sieve crystal. For example, molecular sieve 5A is obtained by replacing the sodium ions of molecular sieve 4A with calcium ions.

From the viewpoint of finished appearance, the range of the pore diameter (effective diameter of the pores) of the zeolite is preferably within the range of 0.50 nm or less, particularly preferably within the range of 0.10 to 0.50 nm, and even more particularly It is preferably within the range of 0.20 to 0.50 nm.

Note that the pore diameter of zeolite can be measured by a nitrogen gas adsorption method.

When using zeolite in the coating composition of the present invention, the amount used is 0.1 to 30% by mass, especially 3% by mass, based on the total solid content of polyaspartic acid ester (A) and polyisocyanate compound (B). From the viewpoint of pot life and finished appearance, the content is preferably in the range of 30% by mass, more particularly 5 to 20% by mass.

A rheology control agent can be used in the coating composition of the present invention for the purpose of controlling the fluidity of the coating and improving the finished appearance and painting workability.

Specific examples of rheology control agents include clay minerals (e.g., metal silicates, montmorillonite), acrylic resins (e.g., polymers and oligomers with acrylic esters or methacrylic esters in the molecule). ), polyolefins (e.g., polyethylene, polypropylene, etc.), amides (higher fatty acid amides, polyamides, oligomers, etc.), polycarboxylic acids (including derivatives having at least two or more carboxyl groups in the molecule), cellulose ( nitrocellulose, acetyl cellulose, cellulose ether, etc.), urethane (polymer, oligomer, etc. containing a urethane structure in the molecule), urea (polymer, oligomer, etc. containing a urea structure in the molecule), urethane urea ( Examples include polymers and oligomers containing urethane structures and urea structures in their molecules.

Among the above, acrylic resin, urea, and urethane urea can be preferably used from the viewpoint of finished appearance.

Commercially available rheology control agents include amide waxes such as Disparon 6900 (manufactured by Kusumoto Kasei Co., Ltd.), Disparon A603 (manufactured by Kusumoto Kasei Co., Ltd.), Thikusol W300 (manufactured by Kyoeisha Chemical Co., Ltd.); Polyethylene waxes such as those manufactured by Kusumoto Kasei Co., Ltd.; cellulose-based waxes such as CAB (cellulose acetate butyrate, manufactured by Eastman Chemical Products), HEC (hydroxyethyl cellulose), hydrophobized HEC, and CMC (carboxymethyl cellulose); Rheology control agent: Urethane urea rheology control agent such as BYK-410, BYK-411, BYK-420, BYK-425 (manufactured by BYK Chemie Co., Ltd.); Fluonon SA-345HF (Kyoeisha Chemical Co., Ltd.) and higher fatty acid amide rheology control agents such as Fluonon HR-4AF (Kyoeisha Kagaku Co., Ltd.).

When using the rheology control agent in the coating composition of the present invention, the amount used is 0.1 to 20% by mass, based on the total solid content of the polyaspartic acid ester (A) and the polyisocyanate compound (C). In particular, it is preferably within the range of 0.5 to 15% by mass, and more particularly 0.8 to 10% by mass, from the viewpoint of finished appearance and painting workability.

The coating composition of the present invention further includes a pigment dispersant, a surface conditioner, a surfactant, an antifoaming agent, a resin other than polyaspartic acid ester (A) (for example, an epoxy resin, etc.), and a curing agent, as necessary. (excluding polyisocyanate compound (B)), a preservative, an antifreeze agent, etc. can be contained.

Since this paint contains a polyisocyanate compound (B) having free isocyanate groups as a constituent component, the crosslinking reaction with the base resin polyaspartic acid ester (A) proceeds at room temperature. It is a two-component paint consisting of a main agent containing component A) and a curing agent containing component (B).Usually, the main agent and curing agent are mixed just before painting, and a solvent such as an organic solvent is added as necessary. It is suitably used by adding it to adjust the viscosity.

In this case, it is generally preferable that components used as necessary be contained in the main ingredient. Mixing can be performed using a mixing device such as a disper or a homogenizer.

The coating composition of the present invention is a high solid content coating composition, and can reduce the amount of volatile substances such as VOCs emitted during coating. Specifically, the coating solid content (nonvolatile content) concentration during coating can be 70% by mass or more, particularly 80% by mass or more.

In this specification, the paint solid content (non-volatile content) concentration during painting is determined by weighing 1.0 g of a sample in a tin plate immediately before painting, which has been adjusted to a viscosity suitable for painting at a temperature of 20°C and a humidity of 60%. It can be determined by removing volatile components at a heating temperature of 105° C. for 3 hours and calculating the remaining amount as a mass percentage.

The coating composition of the present invention can be applied, for example, by dip coating, brush coating, roll brush coating, spray coating, roll coating, spin coating, dip coating, bar coating, flow coating, electrostatic coating, airless coating, and electrodeposition coating. This can be done by a coating method such as , die coating or the like.

Examples of objects to be coated include cold-rolled steel sheets, black-skinned steel sheets, alloyed galvanized steel sheets, electrogalvanized steel sheets, etc., as well as construction machines or industrial machines such as bulldozers, hydraulic excavators, and wheel loaders made of these materials. I can do it. These may be subjected to shot blasting, surface conditioning, surface treatment, etc., and further may be coated with an undercoat, if necessary.

The coating composition of the present invention has excellent weather resistance and corrosion resistance, and is a high solid content coating composition that can be directly applied to metal materials. It can be suitably used as a one-coat top coat paint applied directly to metal materials.

Hereinafter, the present invention will be explained in more detail with reference to Production Examples, Examples, and Comparative Examples, but the present invention is not limited thereto. In each example, "part" indicates part by mass, and "%" indicates mass %.

Manufacture of coating composition Example 1 Coating composition No. Production of Coating Composition No. 1 By the following steps 1 and 2, coating composition No. 1 was prepared. I got 1.

Process 1
Aspartic acid ester resin (A-1) 49.5 parts (solid content), polyol compound (D-1) 5.5 parts (solid content), Variace B-33 (Note 1) 18 parts, Typeke CR-95 ( Note 2) 8 parts, Carbon MA-100 (Note 3) 1 part, BYK-161 (Note 4) 3 parts, TINUVIN 400 (Note 5) 2 parts, TINUVIN 123 (Note 6) 2 parts, BYK-052N (Note 7) By mixing 0.01 part and 0.05 part of BYK-300 (note 8) and stirring, and adjusting the solid content concentration with a solvent, paint composition No. 80 mass% solid content was prepared. A main ingredient of No. 1 was obtained.

In the above, the extender pigment and the color pigment were added and mixed as a pigment dispersion paste prepared using 20 parts of aspartic acid ester resin (A-1).

Step 2 45.1 parts of the polyisocyanate compound (D-1) and 7.0 parts of the epoxy group-containing silane coupling agent (B-1) were added to the base material obtained in Step 1 above, and the solid content concentration was adjusted to the solvent concentration. By adjusting the coating composition No. 80% by mass solid content. I got 1.

Examples 2 to 26 and Comparative Examples 1 to 4 Coating composition No. Production of each coating composition No. 2 to 30 in the same manner as in Example 1 except that the formulations shown in Table 1 were used. I got 2-30. In addition, coating composition No. Numbers 27 to 30 are for comparative examples.

Note that the raw material formulations (values) in Table 1 are solid mass.

In addition, each raw material in the table is as follows.

Polyaspartic acid ester compound (A)
Polyaspartic acid ester (A-1): Desmophen NH-1420: trade name, manufactured by Covestro, polyaspartic acid ester, amine value 201. Molecular weight 554.7 Viscosity 1000mPa・s
Polyaspartic acid ester (A-2): Desmophen NH-1423LF: Product name, manufactured by Covestro, polyaspartic acid ester, amine value 230, molecular weight 554.7, viscosity 1500 mPa・s
Polyaspartic acid ester (A-3): Desmophen NH-1220: Product name, manufactured by Covestro, polyaspartic acid ester, amine value 206, molecular weight 460.6, viscosity 100 mPa・s
Polyisocyanate compound (B)
Polyisocyanate compound (B-1): Desmodur N 3900: trade name, manufactured by Covestro, low viscosity HDI isocyanurate, NCO group content 23.5%. Viscosity at 23℃ 700mPa・s
Polyisocyanate compound (B-2): Desmodur N 3600: trade name, manufactured by Covestro, HDI isocyanurate, NCO group content 23%. Viscosity at 23℃ 1200mPa・s
Polyisocyanate compound (B-3): Desmodur N 3200: trade name, manufactured by Covestro, HDI bullet type isocyanate, NCO group content 23%. Viscosity at 23℃ 2500mPa・s
Polyisocyanate compound (B-4): TOLONATE Viscosity at 23℃ 900mPa・s
Epoxy group-containing silane coupling agent (C)
Epoxy group-containing silane coupling agent (C-1): “KBM-403”: trade name, manufactured by Shin-Etsu Chemical Co., Ltd., γ-glycidoxypropyltrimethoxysilane, epoxy equivalent: 236, molecular weight: 236.

Epoxy group-containing silane coupling agent (C-2): “KBE-402”: trade name, manufactured by Shin-Etsu Chemical Co., Ltd., γ-glycidoxypropylmethyldiethoxysilane, epoxy equivalent: 248, molecular weight: 248.

Epoxy group-containing silane coupling agent (C-3): "MP-200": trade name, manufactured by Momentive, condensate of γ-glycidoxypropyltrimethoxysilane, epoxy equivalent: 205.

Epoxy resin (1): "JER-828": trade name, manufactured by Mitsubishi Chemical Corporation, bisphenol A type liquid epoxy resin, epoxy equivalent: 188.

Polyol compound (D)
Polyol compound (D-1): "Desmophene XP-2488": trade name, manufactured by Covestro, polyester polyol, hydroxyl value 528. Molecular weight 1400
Polyol compound (D-2): "EXCENOL 750ED": trade name, manufactured by AGC, polyester polyol, hydroxyl value 760, molecular weight 300.

Polyol compound (D-3): “Joncryl507”: trade name, manufactured by BASF, hydroxyl group-containing acrylic resin, hydroxyl value 140. Molecular weight 2200.

Polyol compound (D-4): "TA22-981": trade name, manufactured by Resonac, polyester polyol, hydroxyl value 55, molecular weight 2000.

Polyol compound (D-5): "Sannix GP-3000": trade name, manufactured by Sanyo Chemical Co., Ltd., polyether polyol, hydroxyl value 56, molecular weight 3000.

(Note 1) Variace B-33: Manufactured by Sakai Chemical Industry Co., Ltd., trade name, barium sulfate, average particle size 0.3 μm
(Note 2) Typeke CR-95: Manufactured by Ishihara Sangyo Co., Ltd., trade name, titanium dioxide (Note 3) Carbon MA-100: Manufactured by Mitsubishi Chemical Corporation, trade name, carbon black (Note 4) BYK-161: BYK Chemie Co., Ltd. Manufactured by the company, trade name, wetting and dispersing agent (Note 5) TINUVIN400: B. A. S. F. Manufactured by, trade name, hydroxyphenyltriazine ultraviolet absorber (Note 6) TINUVIN123: B. A. S. F. Manufactured by BYK Co., Ltd., product name, hindered amine light stabilizer (Note 7) BYK-052N: Manufactured by BYK Co., Ltd., product name, antifoaming agent, alkyl vinyl ether copolymer (Note 8) BYK-300: Manufactured by BYK Co., Ltd., product name , silicone surface conditioner (Note 9) Neostan U-100: manufactured by Nitto Kasei Co., Ltd., trade name, dibutyltin dilaurate, urethane curing catalyst (Note 10) Silyl group-containing modified polyisocyanate X1:
89.5 parts of 3-aminopropyltrimethoxysilane and 0.04 part of methoquinone were placed in a flask, heated to 80°C, and air was introduced into the liquid to cause bubbling and stirring. 110 parts of di-propyl fumarate was added dropwise to this over 2 hours, maintained at 80°C for 1 hour, further aged at 50°C for 1 week, and 3-(N-(1,2-bis(i-propyl) 199 parts of a mixture containing 95% carbonyl)ethyl)amino)propyltrimethoxysilane was obtained. In another flask, 280 parts of mineral spirit, 224 parts of "Swasol 1000" (naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), "Duranate TSA-100" (hexamethylene diisocyanate-based modified isocyanurate polyisocyanate, Asahi Kasei 550 parts of 20.6 wt % (trade name, isocyanate group content, manufactured by Co., Ltd.) were added thereto, and the mixture was stirred at room temperature. To this, 108 parts of a mixture containing 95% of 3-(N-(1,2-bis(i-propoxycarbonyl)ethyl)amino)propyltrimethoxysilane was added dropwise over 2 hours, and then kept at 60°C for 1 hour. Then, the solution was cooled to room temperature to obtain a silyl group-containing modified polyisocyanate X1 solution with a nonvolatile content concentration of 56%. The concentration of isocyanate groups contained in 1 g of the solution was 2.09 mmol/g (3.72 mmol/g in terms of nonvolatile content).

(Note 11) Silyl group-containing modified polyisocyanate X2:
89.5 parts of 3-aminopropyltrimethoxysilane, 0.04 part of methquinone, and 4 parts of "Swasol 1000" (naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name) were placed in a flask, and air was introduced into the liquid. After bubbling and stirring, 104 parts of isobornyl acrylate was added dropwise over 2 hours, and the mixture was maintained at 50° C. for 1 hour. It was further aged at 50°C for one week, and 3-(N-(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane/3-aminopropyltrimethoxysilane/3-(N,N-di( 198 parts of a mixture containing 2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 74/13/13 was obtained. The total amount of (primary amino group+secondary amino group) in 1 g of the mixture was 2.20 mmol.

In another flask, 273 parts of mineral spirit, 223 parts of "Swasol 1000" (naphtha-based solvent, manufactured by Maruzen Petrochemical Co., Ltd., trade name), and 500 parts of "Duranate TSA-100" were placed and stirred at room temperature. To this, 3-(N-(2-(isobornyloxycarbonyl)ethyl)amino)propyltrimethoxysilane/3-aminopropyltrimethoxysilane/3-(N,N-di(2-(isobornyloxycarbonyl)ethyl)amino) After 111 parts of a mixture containing Roxycarbonyl)ethyl)amino)propyltrimethoxysilane in a molar ratio of 74/13/13 was added dropwise over 2 hours, the mixture was maintained at 60°C for 2 hours, cooled to room temperature, and the nonvolatile content was A silyl group-containing modified polyisocyanate X2 solution having a concentration of 55% was obtained. The concentration of isocyanate groups contained in 1 g of the solution was 1.99 mmol/g (3.62 mmol/g in terms of nonvolatile content).

(Note 12) Silyl group-containing modified polyisocyanate X3:
89 parts of methyl acetate, which is a linear saturated ester, and 179 parts of 3-aminopropyltrimethoxysilane were placed in a flask under a nitrogen atmosphere, and the mixture was stirred at room temperature. To this, 0.58 part of a 28% methanol solution of sodium methoxide was added as a catalyst, and the mixture was stirred, heated to 70°C, and aged for one day. The reaction rate of 3-aminopropyltrimethoxysilane was 97%, and approximately the same mole of methanol as the reacted 3-aminopropyltrimethoxysilane was produced as a by-product. Thereafter, 1.1 parts of bis(2-ethylhexyl) phosphoric acid was added as an acidic compound, and methanol and remaining methyl acetate were removed and concentrated under reduced pressure at 50°C to 70°C. As a product, 222 parts of crude 3-acetamidopropyltrimethoxysilane containing catalyst-derived residue was obtained. 62 parts of butyl acetate and 500 parts of "Duranate TSA-100" were placed in another flask under a nitrogen atmosphere, and the mixture was stirred at room temperature. 55 parts of crude 3-acetamidopropyltrimethoxysilane was added to this and heated at 110°C for 7 hours to adduct the secondary amide group to the isocyanate group, producing silyl group-containing modified polyisocyanate X3 with a nonvolatile content concentration of 90%. A solution was obtained. The concentration of isocyanate groups contained in 1 g of the solution was 3.49 mmol/g (3.88 mmol/g in terms of nonvolatile content).

(Note 13) Molecular sieve 3A: Union Showa Co., Ltd., trade name, sodium calcium aminosilicate, pore size 0.25 nm
(Note 14) Molecular sieve 5A: Union Showa Co., Ltd., trade name, sodium calcium aminosilicate, pore size 0.42 nm
(Note 15) Molecular sieve 13X: Union Showa Co., Ltd., trade name, sodium calcium aminosilicate, pore size 1.0 nm
In addition, for the preparation and performance evaluation of the test plate, the test plate was prepared according to the following, and the results obtained by subjecting it to the test are also shown in Table 1.

Preparation of test plate Each paint composition No. 1 to 30 were air-sprayed (pressure: 0.4 MPa) to a dry film thickness of 80 μm, set at 20°C for 10 minutes, and heated and dried at 60°C for 30 minutes using an electric hot air dryer. Each coating composition No. 1 was further cured at 20°C for 168 hours. Test plates numbered 1 to 30 were obtained.

Performance evaluation Each coating composition No. Test plates of Nos. 1 to 30 and each coating composition were subjected to performance tests for the following test items, and the performance was evaluated based on the following evaluation criteria. The performance evaluation results are also shown in Table 1.

Finished appearance: The appearance of the painted surface of each test plate was evaluated visually and by gloss value.
◎: Good smoothness and 60 degree gloss value of 80 or more.
○: Good smoothness and 60 degree gloss value of 70 or more and less than 80.
Δ: Slight deterioration of the finished appearance of at least one type selected from armpits, waviness, shiny wrinkles, and dusty skin is observed, or the 60 degree gloss value is 60 or more and less than 70.
×: At least one type of finished appearance selected from armpits, waviness, shiny wrinkles, and dusty skin is significantly deteriorated, or the 60 degree gloss value is less than 60.

Pencil hardness: In accordance with JIS K 5600-5-4, place the lead of a pencil on the test coated board surface at an angle of about 45 degrees, and press it forward against the test coated board surface as hard as you can without breaking the lead. It was moved approximately 10 mm at a uniform speed. The hardness code of the hardest pencil that did not break the paint film was defined as the pencil hardness.
◎: 2H or more ○: H or more and less than 2H △: F or more and less than H The paint was spray-painted to a dry film thickness of 60 μm, and the drying time to the touch was measured until the paint no longer stuck to the finger.
◎: Drying time less than 20 minutes ○: Drying time 20 minutes or more and less than 30 minutes △: 30 minutes or more and less than 45 minutes Each test coated board with cross cuts reaching the substrate was sprayed with a 5% sodium chloride aqueous solution adjusted to pH 7.0 in an atmosphere of 35° C. for 168 hours, and then the width of one side of the blisters from the cut portion was evaluated.
◎: Less than 1.0 mm ○: 1.0 mm or more and less than 2.0 mm △: 2.0 mm or more and less than 3.0 mm ×: 3.0 mm or more Weather resistance: Specified in JIS B 7754 for each test plate Using a Super After 1500 hours (750 cycles) of repeated testing, the 60 degree gloss retention (GR%) and color difference (ΔE) of each pre-coated plate (initial coated plate) were measured and evaluated based on the following criteria.
◎: 60 degree gloss retention rate (GR%) is 80 or more and color difference (ΔE) is less than 2.0.
○: 60 degree gloss retention (GR%) is 70 or more and less than 80 or color difference (ΔE) is 2.0 or more and less than 3.0.
Δ: 60 degree gloss retention (GR%) is 50 or more and less than 70 or color difference (ΔE) is 3.0 or more and less than 5.0.
×: 60 degree gloss retention (GR%) is less than 50 or color difference (ΔE) is 5.0 or more.

Pot life: Coating composition No. 1 containing zeolite (molecular sieve). For coating compositions No. 23 to 26, paint composition No. In comparison with No. 16, the pot life was evaluated based on the viscosity increase rate.

When the viscosity of each paint composition was measured using an Iwata cup, the viscosity increase rate after 1 hour (Iwata cup viscosity after 1 hour (seconds)/initial Iwata cup viscosity (seconds)) was 4.0 for No. 16. However, each No. 23 is 1.4, No. 24 is 1.3, No. 25, is 1.1, No. 26 was 1.2.

It is possible to provide a high solid content coating composition that has excellent weather resistance, corrosion resistance, and coating hardness, and can be directly coated on metal materials.

Claims (8)

A silyl group-containing modified product that is a reaction product whose raw materials are components containing a polyaspartic acid ester (A), an alkoxysilane having a primary amino group (a1), a carboxylic acid alkyl ester (a2), and a polyisocyanate (a3). Contains a polyisocyanate compound (B) containing a polyisocyanate, an epoxy group-containing silane coupling agent (C), and a polyol (D) having a weight average molecular weight of 250 to 2300 and a hydroxyl value within the range of 50 to 800. A high solid content coating composition having a solid content concentration of 70% by mass or more. The high solid content coating composition according to claim 1, wherein the polyaspartic acid ester (A) contains a polyaspartic acid ester having a secondary amino group represented by the following formula (1).
⁽ wherein ^, It is an organic group that is inert to isocyanate groups, and n is an integer of 2 or more.) The high solid content coating composition according to claim 1 or 2, wherein the polyol (D) contains a polyester polyol and/or a polyether polyol. The high solid content coating composition according to claim 1 or 2, further comprising a pigment. The high solid content coating composition according to claim 1 or 2, further comprising zeolite. The one-coat high solid content coating composition according to claim 1 or 2. A coating method comprising coating an object to be coated with the high solid content coating composition according to claim 1 or 2. A construction machine or industrial machine coated with the high solid content coating composition according to claim 1 or 2.