CN116964163A

CN116964163A - Two-component coating composition

Info

Publication number: CN116964163A
Application number: CN202180095263.3A
Authority: CN
Inventors: 石山雄一; 田中宏明; 筿田尚志; 平户伸治
Original assignee: Kansai Paint Co Ltd
Current assignee: Kansai Paint Co Ltd
Priority date: 2021-03-08
Filing date: 2021-12-21
Publication date: 2023-10-27
Also published as: WO2022190562A1; JPWO2022190562A1

Abstract

The present application relates to a two-component coating composition comprising a hydroxyl-containing acrylic resin (A), a polyisocyanate compound (B), a zeolite (C) and a triazine ultraviolet absorber (D), wherein the content of the resin (A) is 60 to 90 mass%, the content of the compound (B) is 10 to 40 mass%, the content of the zeolite (C) is 10 to 40 mass%, and the content of the ultraviolet absorber (D) is 0.1 to 10 mass%, based on the total amount of the solid components of the resin (A) and the compound (B).

Description

Two-component coating composition

Technical Field

The present application relates to a two-component coating composition excellent in corrosion resistance and weather resistance.

Background

In the coating of construction machines or industrial machines such as bulldozers, hydraulic excavators, and wheel loaders, various coating compositions are used according to desired performance requirements.

In recent years, manufacturers of construction machines and industrial machines have demanded coatings having higher corrosion resistance and weather resistance.

Patent document 1 discloses a coating composition comprising a main agent (I) containing a resin having a hydroxyl group and a curing agent (II), wherein the main agent (I) contains an aqueous polymer polyol, and the curing agent (II) contains a polyisocyanate having water dispersibility and an organic solvent.

Patent document 2 discloses, as a method for forming a multilayer coating film excellent in both corrosion resistance and weather resistance, a method for limiting the difference in surface tension between a primer coating film and a topcoat coating film in a multilayer coating film composed of a wet-on-wet primer coating film and a topcoat coating film, and in the method, a primer coating composition containing an acrylic resin, an epoxy resin, and an isocyanate compound as resin components is disclosed.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2006-257141

Patent document 2: japanese patent No. 5221822

Disclosure of Invention

Problems to be solved by the application

However, the coating film obtained from the coating composition described in patent document 1 may have insufficient corrosion resistance.

Further, the multilayer coating film obtained by the coating film forming method described in patent document 2 may have insufficient corrosion resistance and insufficient weather resistance.

In view of the above-described conventional circumstances, an object of the present application is to provide a coating composition having excellent corrosion resistance and weather resistance.

Means for solving the problems

As a result of intensive studies, the present inventors have found that the above problems can be solved by a coating composition containing a hydroxyl group-containing acrylic resin, a polyisocyanate compound, zeolite and a triazine ultraviolet absorber, and have completed the present application.

That is, the present application relates to the following <1> to <4>.

<1> a two-component coating composition comprising a hydroxyl group-containing acrylic resin (A), a polyisocyanate compound (B), zeolite (C) and a triazine ultraviolet absorber (D), wherein,

the content of the acrylic resin (A) is 60 to 90% by mass, the content of the polyisocyanate compound (B) is 10 to 40% by mass, the content of the zeolite (C) is 10 to 40% by mass, and the content of the triazine ultraviolet absorber (D) is 0.1 to 10% by mass, based on the total amount of the solid components of the hydroxyl group-containing acrylic resin (A) and the polyisocyanate compound (B).

<2> the two-part coating composition according to <1>, wherein,

the polyisocyanate compound (B) is at least one of an aliphatic polyisocyanate compound, an alicyclic polyisocyanate compound and a modified product thereof.

<3> the two-part type coating composition according to <1> or <2>, wherein,

the zeolite (C) has a pore diameter of 0.5nm or less.

<4> a construction machine or industrial machine coated with the two-component coating composition according to any one of <1> to <3 >.

Effects of the application

The coating composition of the present application uses a hydroxyl group-containing acrylic resin as a base resin and a polyisocyanate compound as a curing agent, and thus also has excellent reactivity.

Further, since zeolite is used as the water absorbing material, a coating film excellent in corrosion resistance and water resistance can be obtained.

Further, since the triazine-based ultraviolet absorber is contained in the coating film at an excellent residual rate, the coating film also has excellent weather resistance.

Therefore, according to the coating composition of the present application, a coating composition that can obtain a coating film excellent in corrosion resistance and weather resistance can be obtained, and further, a coating film excellent in finished appearance can be obtained.

Detailed Description

The coating composition of the present application is a composition containing a hydroxyl-containing acrylic resin (A), a polyisocyanate compound (B), zeolite (C) and a triazine ultraviolet absorber (D). Hereinafter, detailed description will be made.

< hydroxyl-containing acrylic resin (A) >)

The hydroxyl group-containing acrylic resin is generally a copolymer of a hydroxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer. Examples of the method for obtaining the copolymer include a solution polymerization method in an organic solvent and an emulsion polymerization method in water.

The hydroxyl group-containing polymerizable unsaturated monomer is a compound having one or more hydroxyl groups and polymerizable unsaturated bonds in one molecule, and specific examples thereof include: monoesters of (meth) acrylic acid and a glycol having 2 to 8 carbon atoms (preferably 2 to 4), such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 7-hydroxyheptyl (meth) acrylate, and 8-hydroxyoctyl (meth) acrylate; an epsilon-caprolactone modified product of a monoester of (meth) acrylic acid and a glycol having 2 to 8 carbon atoms; n-hydroxymethyl (meth) acrylamide; allyl alcohol, and (meth) acrylic acid esters having polyoxyalkylene chains having hydroxyl groups at the molecular terminals. In the present application, a polymerizable unsaturated monomer having an ultraviolet-absorbing functional group such as 2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone described later is not included in the hydroxyl-containing polymerizable unsaturated monomer, but is included in another polymerizable unsaturated monomer copolymerizable with the hydroxyl-containing polymerizable unsaturated monomer.

Examples of the other polymerizable unsaturated monomer copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer include: methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (trade name, manufactured by Osaka organic chemical industry Co., ltd.) (meth) acrylate cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate, and the like (meth) acrylic acid alkyl or cycloalkyl esters; a polymerizable unsaturated monomer having an isobornyl group such as isobornyl (meth) acrylate; an adamantyl group-containing polymerizable unsaturated monomer such as adamantyl (meth) acrylate; vinyl aromatic compounds such as styrene, α -methylstyrene, and vinyltoluene; an alkoxysilyl group-containing polymerizable unsaturated monomer such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ - (meth) acryloxypropyl trimethoxysilane, and γ - (meth) acryloxypropyl triethoxysilane; perfluoroalkyl (meth) acrylates such as perfluorobutyl ethyl (meth) acrylate and perfluorooctyl ethyl (meth) acrylate; polymerizable unsaturated monomers having fluoroalkyl groups such as fluoroolefins; a polymerizable unsaturated monomer having a photopolymerizable functional group such as a maleimide group; vinyl compounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate and vinyl acetate; carboxyl group-containing polymerizable unsaturated monomers such as (meth) acrylic acid, maleic acid, crotonic acid, and β -carboxyethyl acrylate; nitrogen-containing polymerizable unsaturated monomers such as (meth) acrylonitrile, (meth) acrylamide, N-dimethylaminoethyl (meth) acrylate, N-dimethylaminopropyl (meth) acrylamide, and adducts of glycidyl (meth) acrylate and amine compounds; polymerizable unsaturated monomers having two or more polymerizable unsaturated groups in one molecule, such as allyl (meth) acrylate and 1, 6-hexanediol di (meth) acrylate; epoxy group-containing polymerizable unsaturated monomers such as glycidyl (meth) acrylate, β -methyl glycidyl (meth) acrylate, 3, 4-epoxycyclohexylmethyl (meth) acrylate, 3, 4-epoxycyclohexylethyl (meth) acrylate, 3, 4-epoxycyclohexylpropyl (meth) acrylate, and allyl glycidyl ether; (meth) acrylic acid esters having a polyoxyalkylene chain having an alkoxy group at a molecular end; 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, sodium salt of styrenesulfonic acid, sulfoethyl methacrylate, sodium salt, ammonium salt and other polymerizable unsaturated monomers having sulfonic acid groups; polymerizable unsaturated monomers having a phosphate group such as 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, and 2-methacryloyloxypropyl acid phosphate; polymerizable unsaturated monomers having an ultraviolet-absorbing functional group, such as 2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2-hydroxy-4- (3-acryloyloxy-2-hydroxypropoxy) benzophenone, 2 '-dihydroxy-4- (3-methacryloyloxy-2-hydroxypropoxy) benzophenone, 2' -dihydroxy-4- (3-acryloyloxy-2-hydroxypropoxy) benzophenone, and 2- (2 '-hydroxy-5' -methacryloyloxyethylphenyl) -2H-benzotriazole; 4- (meth) acryloyloxy-1, 2, 6-pentamethylpiperidine, 4- (meth) acryloyloxy-2, 6-tetramethylpiperidine 4-cyano-4- (meth) acrylamido-2, 6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acrylamido-2, 6-tetramethylpiperidine 1- (meth) acryloyl-4-cyano-4- (meth) acrylamido-2, 6-tetramethylpiperidine, 4-crotonyloxy-2, 6-tetramethylpiperidine ultraviolet stable polymerizable unsaturated monomers such as 4-crotonylamino-2, 6-tetramethylpiperidine and 1-crotonyl-4-crotonyloxy-2, 6-tetramethylpiperidine; and polymerizable unsaturated monomer compounds having a carbonyl group such as acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formylstyrene, and vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, and vinyl butyl ketone). These may be used singly or in combination of two or more.

From the viewpoint of coating film hardness and corrosion resistance, the hydroxyl group-containing acrylic resin (A) preferably has a hydroxyl group value in the range of 30 to 300mgKOH/g, particularly 40 to 250 mgKOH/g.

From the viewpoint of reactivity with the polyisocyanate compound (B), the hydroxyl group-containing acrylic resin (a) preferably has an acid value in the range of 20mgKOH/g or less, particularly 1 to 15 mgKOH/g.

The hydroxyl group-containing acrylic resin (a) generally preferably has a weight average molecular weight in the range of 3000 to 100000, particularly 3000 to 50000, further particularly 4000 to 30000.

The "weight average molecular weight" or "number average molecular weight" in the specification 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 K0124-2011.

The gel permeation chromatograph used was "HLC 8120GPC" (manufactured by koch corporation). Four columns, "TSKgel G-4000HXL", "TSKgel G-3000HXL", "TSKgel G-2500HXL", "TSKgel G-2000HXL" (all manufactured by Tonkel corporation under the trade name of Toolsew.) were used as columns, and measurement was performed under conditions of tetrahydrofuran as the mobile phase, a measurement temperature of 40℃and a flow rate of 1 ml/min, and a detector of RI.

< polyisocyanate Compound (B) >)

The polyisocyanate compound (B) is a compound having two or more free isocyanate groups in one molecule.

As the polyisocyanate compound (B), a polyisocyanate compound conventionally used in polyurethane production can be used. Specifically, examples thereof include aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, aromatic aliphatic polyisocyanate compounds, aromatic polyisocyanate compounds and crude products thereof, modified products of these polyisocyanate compounds, and the like. The polyisocyanate compound (B) may be used singly or in combination of two or more.

Specific examples of the aliphatic polyisocyanate compound include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene Diisocyanate (HDI), dodecamethylene diisocyanate, 1,6, 11-undecane triisocyanate, 2, 4-trimethylhexamethylene diisocyanate, lysine diisocyanate, methyl 2, 6-diisocyanatohexanoate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, and 2-isocyanatoethyl-2, 6-diisocyanatohexanoate.

Specific examples of the alicyclic polyisocyanate compound include isophorone diisocyanate (IPDI), dicyclohexylmethane-4, 4' -diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis (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 compound include m-and/or p-Xylylene Diisocyanate (XDI), α, α, α ', α' -tetramethylxylylene diisocyanate (TMXDI), and the like.

Specific examples of the aromatic polyisocyanate compound include 1, 3-and/or 1, 4-phenylene diisocyanate, 2, 4-and/or 2, 6-Toluene Diisocyanate (TDI), crude TDI, 2,4 '-and/or 4,4' -biphenylmethane diisocyanate (MDI), 4 '-diisocyanatobiphenyl, 3' -dimethyl-4, 4 '-diisocyanato diphenylmethane, crude MDI, 1, 5-naphthalene diisocyanate, 4',4 "-triphenylmethane triisocyanate, meta-and/or para-isocyanatophenylsulfonyl isocyanates, and the like.

Specific examples of the modified product of the polyisocyanate compound include modified products of polyisocyanate compounds such as modified MDI (urethane-modified MDI, carbodiimide-modified MDI, and tri-hydrocarbyl-modified MDI), urethane-modified TDI, biuret-modified HDI, isocyanurate-modified HDI, and isocyanurate-modified IPDI; and mixtures of two or more thereof [ e.g., a mixture of modified MDI and urethane modified TDI ].

From the viewpoints of corrosion resistance and weather resistance of the coating composition of the present application, among the above polyisocyanate compounds (B), aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds and their modified products can be suitably used. The number average molecular weight of the polyisocyanate compound (B) is preferably 3000 or less, particularly preferably in the range of 100 to 1500.

Examples of the commercial products of the polyisocyanate compound (B) include super N3300 (manufactured by chemical company), TPA100 (manufactured by chemical company), BASONAT HI100AP (manufactured by BASF corporation), コ fire HXR (manufactured by chemical company).

In the coating composition of the present application, the content of the hydroxyl group-containing acrylic resin (a) is 60 to 90 mass%, preferably 70 to 90 mass%, and the content of the polyisocyanate compound (B) is 10 to 40 mass%, preferably 10 to 30 mass%, based on the total amount of the solid components of the hydroxyl group-containing acrylic resin (a) and the polyisocyanate compound (B), from the viewpoints of corrosion resistance, weather resistance, and coating film hardness.

< zeolite (C) >)

The zeolite is a generic name of crystalline aluminosilicate, and is composed of Al, si, O, cations (positive ions) and SiO ₄ And AlO ₄ Tetrahedral structure (in Si ⁴⁺ Or Al ³⁺ Tetrahedra formed as centers) are basic structural compounds. Since they are connected in a complicated and regular manner, fine pores having approximately the same size as small molecules having diameters of several angstroms to tens of angstroms, which are characteristic of zeolite, are regularly formed in one, two or three dimensions. Cations are present in the pores, and various functions of zeolite are exhibited based on the cations. In the pores of zeolite, only molecules smaller than its diameter can enter, and can be sieved with macromolecules, so some zeolites are called molecular sieves.

Zeolite bagComprises natural zeolite containing hydrous aluminosilicate as main ingredient and Na ₂ O·Al ₂ O ₃ ·xSiO ₂ ·yH ₂ Synthetic zeolite with O as main component. Synthetic zeolites, also known as artificial zeolites, are manufactured by a dry process in which sodium carbonate, silica, alumina or kaolin is co-fused, or a wet process in which sodium silicate is combined with sodium aluminate to precipitate a gel. The natural zeolite and the synthetic zeolite have ion exchange capability, the crystal structure of the natural zeolite and the synthetic zeolite can not change even if the natural zeolite and the synthetic zeolite are dehydrated, and the molecular size of the natural zeolite and the synthetic zeolite can be obtained after the natural zeolite and the synthetic zeolite are dehydrated, so that the natural zeolite and the synthetic zeolite have larger adsorption capability. In addition, zeolite obtained by crystallizing and dehydrating sodium aluminosilicate gel by hydrothermal synthesis to obtain a certain size of fine pores is generally called a molecular sieve.

As the zeolite (C), zeolite generally called molecular sieve can be suitably used from the viewpoints of corrosion resistance and finished appearance. Zeolite molded into powder or granule is commercially available, and molecular sieve 3A, molecular sieve 4A, molecular sieve 5A, molecular sieve 13X, etc. are commercially available depending on the type of zeolite as a raw material. The numbers indicate the approximate diameter (angstrom) of the pores, the capital letters indicate the zeolite type, a indicates LTA-type zeolite, and X indicates FAU-type zeolite.

Among the above molecular sieves, molecular sieve 3A, particularly molecular sieve 5A, can be suitably used.

The effective diameter of the pores of the molecular sieve changes according to the position and size of the metal cations in the vicinity of the pores, for example, the 5A type is formed by replacing the 4A type sodium ions with calcium ions.

The pore diameter (effective pore diameter) of the zeolite (C) is preferably in the range of 0.50nm or less, more preferably 0.10 to 0.50nm, and even more preferably 0.30 to 0.50nm, from the viewpoints of corrosion resistance and finished appearance.

The zeolite (C) content in the coating composition of the present application is 10 to 40 mass%, preferably 15 to 30 mass%, and more preferably 15 to 25 mass% based on the total amount of the solid components of the hydroxyl group-containing acrylic resin (a) and the polyisocyanate compound (B) from the viewpoints of corrosion resistance and finished appearance.

< triazine ultraviolet absorber (D) >)

The ultraviolet absorber is a compound that absorbs ultraviolet light, and is contained in particular for the purpose of suppressing photodegradation of a resin in the coating composition and improving weather resistance of a coating film.

The triazine ultraviolet light absorber (D) is a compound having a heterocyclic structure in which a triazine ring is present in the molecule.

The triazine ultraviolet light absorber (D) is superior to benzotriazole and benzophenone ultraviolet light absorbers in terms of the residual property in the coating film, and therefore has an excellent effect of improving weather resistance.

Specific examples of the triazine ultraviolet light absorber (D) include 2, 4-bis (2, 4-dimethylphenyl) -6- (2-hydroxy-4-isooctylphenyl) -1,3, 5-triazine, 2- [4 ((2-hydroxy-3-dodecyloxypropyl) -oxy) -2-hydroxyphenyl ] -4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazine, 2- [4- ((2-hydroxy-3-tridecyloxypropyl) -oxy) -2-hydroxyphenyl ] -4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazine, 2- (2, 4-dihydroxyphenyl) -4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazine, and the like.

Examples of the commercial products of the ultraviolet absorber include TINUVIN400, TINUVIN 477, TINUVIN 479 (trade name, TINUVIN is a registered trademark manufactured by BASF corporation), and the like.

The triazine ultraviolet light absorber (D) may be used singly or in combination of two or more.

From the viewpoint of weather resistance, the content of the triazine ultraviolet light absorber (D) is in the range of 0.1 to 10 mass%, preferably 0.2 to 8 mass%, more preferably 0.3 to 5 mass%, and even more preferably 0.5 to 5 mass% relative to the total amount of the solid components of the hydroxyl group-containing acrylic resin (a) and the polyisocyanate compound (B).

As the ultraviolet absorber, in addition to the triazine ultraviolet absorber (D), a benzotriazole ultraviolet absorber, a benzophenone ultraviolet absorber, or the like may be used as needed.

In order to improve corrosion resistance, the coating composition of the present application may contain a rust inhibitive pigment. Examples of the rust inhibitive pigment include zinc oxide, phosphite compounds, phosphate compounds, molybdate compounds, bismuth compounds, and metal ion-exchanged silica.

Examples of the phosphite compound include calcium phosphite compounds such as EXPERT NP-1000 and EXPERT NP-1020C, and aluminum phosphite compounds such as EXPERT NP-1100 and EXPERT NP-1102 (EXPERT series are all manufactured by Toho pigment industries Co., ltd., trade name).

Examples of the phosphate compound include aluminum dihydrogen tripolyphosphate treated with a metal compound. Examples of the metal compound include chlorides, hydroxides, carbonates, and sulfates of zinc, calcium, magnesium, manganese, bismuth, cobalt, tin, zirconium, titanium, strontium, copper, iron, lithium, aluminum, nickel, and sodium.

Examples of the commercial products of aluminum dihydrogen tripolyphosphate treated with the metal compound include K-WHITE 140, K-WHITE Ca650, K-WHITE 450H, K-WHITE G-105, K-WHITE K-82 (both manufactured by Tokiku Co., ltd., trade name), ZAP-2 (manufactured by SHIH SHENG CHEMICAL INDUSTRY Co., ltd.).

Examples of commercial products of the molybdate-based compound include LFmic M-PSN, LFmic MC-400WR, LFmic PM-300, PM-308 (all manufactured by Koch company, trade name), and the like.

Examples of the bismuth compound include bismuth oxide, bismuth hydroxide, basic bismuth carbonate, bismuth nitrate, bismuth silicate, and bismuth organate.

Examples of the metal ion-exchanged silica include calcium ion-exchanged silica and magnesium ion-exchanged silica. As these metal ion-exchanged silica, phosphoric acid modified metal ion-exchanged silica may also be used.

The calcium ion-exchanged silica is silica fine particles formed by introducing calcium ions into a fine porous silica support by ion exchange. Examples of the commercial products of the calcium ion-exchanged silica include SHIELDEX C303, SHIELDEXAC-3, SHIELDEX C-5 (all of which are manufactured by w.r.Grace & co.), and part of the engine system 52 (manufactured by fujishi mountain a corporation).

The magnesium ion-exchanged silica is silica fine particles formed by introducing magnesium ions into a fine porous silica support by ion exchange. Examples of commercial products of magnesium ion-exchanged silica include a case-by-case type of mex 52M (manufactured by fuji corporation), a case-by-case type of beol ACE-110 (manufactured by SNCZ corporation, france), and the like.

In the case of using the rust inhibitive pigment in the coating composition of the present application, the amount of the rust inhibitive pigment to be used is preferably 2 to 25% by mass, more preferably 5 to 20% by mass, and even more preferably 5 to 15% by mass, based on the total amount of the solid components of the hydroxyl-containing acrylic resin (A) and the polyisocyanate compound (B), from the viewpoints of corrosion resistance and finished appearance.

In order to obtain the desired color, colored pigments may be used in the coating compositions of the present application. Specific examples of the coloring pigment include titanium white, zinc molybdate, calcium molybdate, carbon black, graphite, iron black, prussian blue, ultramarine, cobalt blue, copper phthalocyanine blue, indanthrone blue, lead yellow, synthetic iron oxide yellow, iron oxide red, transparent iron oxide red, bismuth vanadate, titanium yellow, zinc yellow, monoazo yellow, ocher, disazo, isoindolone yellow, metal complex salt azo yellow, quinophthalone yellow, benzimidazolone yellow, monoazo red, unsubstituted quinacridone red, azo lake (Mn salt), quinacridone magenta, anthrone orange, anthraquinone red, perylene chestnut, perylene red, diketopyrrolopyrrole-chrome cinnabar, chlorinated phthalocyanine green, brominated phthalocyanine green, pyrazolone orange, benzimidazolone orange, dioxazine violet, perylene violet, and the like.

When a coloring pigment is used in the coating composition of the present application, the amount of the coloring pigment used is preferably 1 to 100% by mass, particularly preferably 10 to 60% by mass, based on the total amount of the solid components of the hydroxyl-containing acrylic resin (a) and the polyisocyanate compound (B), from the viewpoint of the appearance of the finished product.

The coating composition of the present application may contain extender pigments as needed.

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

Among the above extender pigments, barium sulfate or calcium carbonate having an average particle diameter of preferably 0.01 to 5 μm, more preferably 0.05 to 4 μm, and still more preferably 0.05 to 3 μm can be suitably used from the viewpoint of improving the appearance of the finished product.

Examples of commercial products of such extender pigments include, for example, calcium BF-20 (trade name, barium sulfate having an average particle size of 0.03 μm manufactured by sakea chemical industry Co., ltd.), calcium B-33 (barium sulfate having an average particle size of 0.3 μm manufactured by sakea chemical industry Co., ltd.), SPARWITE W-5HB (trade name, barium sulfate powder having an average particle size of 1.6 μm manufactured by Sino-Can Co., ltd.); examples of calcium carbonate include fiber SA-200 (trade name, calcium carbonate having an average particle diameter of 0.08 μm manufactured by Zhu Yuan chemical industry Co., ltd.), and modem 3N (manufactured by Bei Fu Lin Kagaku Co., ltd., trade name, calcium carbonate having an average particle diameter of 1.1 μm), or the like, and the slon SL 1500 (trade name, calcium carbonate having an average particle diameter of 2.5 μm manufactured by bamboo chemical industry co.

In the present specification, the average particle diameter is a value obtained by measuring particle size distribution by a dynamic light scattering method.

Specifically, the average particle diameter is a value measured using, for example, UPA-EX250 (trade name, manufactured by Nikkin corporation, particle size distribution measuring apparatus based on dynamic light scattering method).

In the case of using an extender pigment in the coating composition of the present application, the amount of the extender pigment to be used is preferably 20 to 150 mass%, more preferably 40 to 140 mass%, still more preferably 40 to 130 mass% based on the total amount of the solid components of the hydroxyl group-containing acrylic resin (a) and the polyisocyanate compound (B) from the viewpoints of corrosion resistance, appearance of a finished product and hardness of a coating film.

Rheology control agents may be used in the coating compositions of the present application in order to control the flowability of the coating to improve the appearance of the finished product and the coating workability.

Specific examples of the rheology control agent include clay minerals (for example, metal silicate, montmorillonite), acrylic resins (for example, materials having a structure composed of a polymer or oligomer of acrylate or methacrylate in the molecule), polyolefins (for example, 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), celluloses (including various derivatives such as nitrocellulose, acetyl cellulose, cellulose ether, etc.), carbamates (polymers or oligomers having a urethane structure in the molecule), ureas (polymers or oligomers having a urea structure in the molecule), and carbamide (polymers or oligomers having a urethane structure and a urea structure in the molecule).

Examples of commercial products of rheology control agents include amide waxes such as dupont 6900 (manufactured by nanben chemical company), dupont a603 (manufactured by nanben chemical company), and doctor W300 (manufactured by co chemical company); polyethylene wax such as dipin 4200 (manufactured by nanben chemical company); cellulose rheology control agents such as CAB (cellulose acetate butyrate, modem, manufactured by the company dyche), HEC (hydroxyethyl cellulose), hydrophobized HEC, CMC (carboxymethyl cellulose), and the like; urethane urea rheology control agents such as BYK-410, BYK-411, BYK-420 and BYK-425 (manufactured by the above-mentioned chemical industries, ltd.); polyolefin rheology control agents such as Fall SA-345HF (manufactured by Kyowa Kagaku Co., ltd.); and a higher fatty acid amide-based rheology control agent such as fein HR-4AF (manufactured by co-Rong chemical Co., ltd.).

In the case of using the rheology control agent in the coating composition of the present application, the amount of the rheology control agent to be used is in the range of 0.1 to 20% by mass, preferably 0.5 to 15% by mass, and more preferably 0.8 to 10% by mass, based on the total amount of the solid components of the hydroxyl group-containing acrylic resin (a) and the polyisocyanate compound (B), from the viewpoints of the appearance of the finished product and the coating workability.

The coating composition of the present application may further contain, if necessary, a pigment dispersant, a surface conditioner, a surfactant, a defoaming agent, a resin other than the hydroxyl group-containing acrylic resin (a) (for example, a polyester resin, an epoxy resin, etc.), a curing agent (other than the polyisocyanate compound (B)), a curing catalyst, a preservative, an antifreezing agent, etc.

The coating composition of the present application contains a polyisocyanate compound (B) having a free (free) isocyanate group as a constituent component, and thus undergoes a crosslinking reaction with a hydroxyl group-containing acrylic resin (a) as a base resin at ordinary temperature. Therefore, the coating composition of the present application is a two-component coating composition comprising a main component containing the component (a) and a curing agent containing the component (B), and usually, the main component and the curing agent are mixed immediately before coating, and if necessary, a solvent such as an organic solvent is added to adjust the viscosity and the viscosity is suitably used.

In this case, the component (C), the component (D), and the component used as needed are preferably blended in advance on the main agent side in general. The mixing may be performed using a mixing device such as a disperser or a homogenizer.

The coating composition of the present application can be applied by, for example, dip coating, brush coating, roll coating, spray coating, roll coating, spin coating, dip coating, bar coating, flow coating, electrostatic coating, airless coating, electrodeposition coating, die coating, or other coating methods. The thickness of the dried film is usually in the range of 10 μm to 150. Mu.m, preferably 50 μm to 100. Mu.m.

Examples of the coating material include cold-rolled steel sheet, black skin steel sheet, alloyed galvanized steel sheet, electrogalvanized steel sheet, and the like, and bulldozers, hydraulic excavators, construction machines such as wheel loaders, industrial machines, and the like, which are produced from these steel sheets as raw materials. These objects may be subjected to shot blasting, surface conditioning, surface treatment, and the like as required.

The coating composition of the present application is excellent in corrosion resistance and weather resistance, and therefore can be suitably used as a single-coat coating or a top-coat coating in the above-mentioned application to an object to be coated.

Examples

Hereinafter, the present application will be described in more detail with reference to production examples, examples and comparative examples, but the present application is not limited to these. In each example, "parts" represents parts by mass and "%" represents% by mass.

Production example 1

Production of a solution of the hydroxyl-containing acrylic resin (A)

113 parts of a mixed solvent (xylene/n-butanol=80/20) was added to the reaction vessel, the mixture was kept at 80℃and the following "mixture A" was dropped thereto for 4 hours, then 8 parts of di-t-butyl hydroperoxide was added thereto, and the mixture was kept at 80℃for 3 hours to carry out the reaction, and the mixture was adjusted with the mixed solvent (xylene/n-butanol=80/20), whereby a hydroxyl group-containing acrylic resin (A) solution having a solid content of 60% by mass was produced. The hydroxyl value of the resulting solution of the hydroxyl-containing acrylic resin (A) was 94.9mgKOH/g, the acid value was 3.9mgKOH/g, and the weight-average molecular weight was 11000.

"mixture A"

41.6 parts of styrene

6.9 portions of n-butyl acrylate

Isobutyl methacrylate 19 parts

t-Larakuck FM-3 (note 1) 15 parts

17 parts of 2-hydroxyethyl methacrylate

Acrylic acid 0.5 part

Production of coating compositions

Example 1 production of coating composition No.1

Coating composition No.1 was obtained by the following steps 1 to 3.

Step 1: a proper amount of butyl acetate was added to 40 parts (solid content) of the hydroxyl-containing acrylic resin (A) solution obtained in production example 1, 60 parts (note 2) of the hydroxyl-containing acrylic resin (B-33), 3 parts (note 3) of the tard-pair, 1.0 part (note 4) of the BLUE RSK BE, 1.0 part (note 5) of the carbowax MA-100, 10 parts (note 6) of the K-WHITE 105 and 10 parts (note 7) of the molecular sieve 5A (P), and dispersed by a sand mill to obtain a pigment dispersion paste.

Step 2: to 20 parts (solid content) of the hydroxyl group-containing acrylic resin (a) solution obtained in production example 1, 2.0 parts of the pigment dispersion paste obtained in step 1 and TINUVIN400 (note 8) were added, and a surface conditioner, an antifoaming agent, a rheology control agent, and a light stabilizer were added and stirred, and further butyl acetate was added to adjust the solid content, thereby obtaining a main agent paint having a solid content of 65 mass%.

And step 3: 40 parts (solid content) of super high N3300 (note 9) was blended into the base coating material obtained in the step 2, and butyl acetate was added to adjust the solid content, thereby obtaining a coating composition No.1 having a solid content of 55 mass%.

Examples 2 to 18 production of coating compositions No.2 to 18

Coating compositions Nos. 2 to 18 were obtained in the same manner as in example 1, except that the compounding contents of tables 1 to 2 were used.

Comparative examples 1 to 8 production of coating compositions No.19 to 26

Coating compositions Nos. 19 to 26 were obtained in the same manner as in example 1, except that the compounding contents of Table 3 were used.

The acrylic resin (α) solution of the coating composition No.19 of comparative example 1 was prepared as follows.

Production of hydroxyl-free acrylic resin (. Alpha.) solution

113 parts of a mixed solvent (xylene/n-butanol=80/20) was added to the reaction vessel, the mixture was kept at 80℃and the following "mixture B" was dropped thereto for 4 hours, then 0.2 part of di-t-butyl hydroperoxide was added thereto, the reaction was carried out at 80℃for 3 hours, and the mixture was adjusted with the mixed solvent (xylene/n-butanol=80/20), whereby a hydroxyl group-free acrylic resin (. Alpha.) solution having a solid content of 60% by mass was produced. The hydroxyl value of the obtained hydroxyl-free acrylic resin (. Alpha.) was 0.0mgKOH/g, the acid value was 7.7mgKOH/g, and the weight-average molecular weight was 80000.

"mixture B"

30 parts of styrene

30 parts of methyl methacrylate

N-butyl acrylate 39 parts

Acrylic acid 1 part

Evaluation of Performance

The results of the test panels were prepared and tested in accordance with the following procedures, and are shown in tables 1 to 3.

Test plate manufacturing

Each of the coating compositions No.1 to 26 was sprayed onto a rolled steel material SS-400 (size: 2.3X10X105 mm, ra:3.9 μm, ry:34 μm, rz:23 μm) for general structure after shot blasting to give a dried film thickness of 80 μm, and after standing at 20℃for 10 minutes, it was dried by heating at 80℃for 30 minutes using an electric heat drier, and further cured at room temperature (20 ℃) for 168 hours to give each of the test boards of each of the coating compositions No.1 to 26.

Film coating Performance test

The coating film performance test was performed on each of the test boards of each of the coating compositions nos. 1 to 26 according to the test items described later, and the performance evaluation was performed according to the evaluation criteria described later. The test results are shown in tables 1 to 3.

Appearance of finished product (note 19): the coated appearance of each test panel was evaluated by visual inspection and gloss values according to the following criteria.

And (3) the following materials: the smoothness is good, and the 60-degree gloss value is more than 85.

O: the smoothness is good, and the 60-degree gloss value is 75 or more and less than 85.

Delta: a reduction in the appearance of the finished product selected from at least one of moire, matt and peeling was slightly observed, and the 60 degree gloss value was 60 or more and less than 75.

X: the finished product has a substantially reduced appearance selected from at least one of moire, matt, and peeling, and has a60 degree gloss value of less than 60.

Pencil hardness (note 20): according to JIS K5600-5-4, for each test board, a pencil core was placed on the test coated board surface at an angle of about 45 DEG, the pencil core was pressed against the test coated board surface with force with a force that does not break the pencil core, and the pencil was moved forward at a constant speed of about 10mm. The hardness of the hardest pencil whose coating film was not broken was designated as pencil hardness.

And (3) the following materials: h or more.

O: f is more than or equal to H.

Delta: HB or more and less than F.

X: less than HB.

Corrosion resistance (note 21): the substrates were scratched with a knife to reach the cross-wound marks, and the substrates were subjected to a salt spray resistance test in accordance with JIS Z-2371 for 240 hours, and the substrates were evaluated according to the following criteria based on the rust and protrusion widths caused by the knife marks.

And (3) the following materials: the maximum width of the rust and the protrusion is less than 2mm (single side) from the cutting part.

O: the maximum width of the rust and the protrusion is more than 2mm and less than 3mm (one side) from the cutting part.

Delta: the maximum width of the rust and the protrusion is 3mm or more and less than 4mm (one side) from the cutting part.

X: the maximum width of the rust and the protrusion is more than 4mm (one side) from the cutting part.

Weather resistance (note 22): for each test plate, a test plate was evaluated by using a super-day-jet-type device prescribed in JIS B7754, using a 2-hour irradiation of a xenon arc lamp for 1 hour and an irradiation of the same lamp under a rainfall condition for 18 minutes as 1 cycle, and measuring 60-degree gloss retention (GR%) and chromatic aberration (Δe) with respect to each precoated plate (initial coated plate) after completion of a trial and error of 1500 hours (750 cycles), with respect to each precoated plate (initial coated plate), under the following criteria.

And (3) the following materials: the 60-degree gloss retention (GR%) is 80 or more and the color difference (ΔE) is less than 2.0.

O: the 60-degree gloss retention (GR%) is 70 or more and less than 80 or the color difference (delta E) is 2.0 or more and less than 3.0.

Delta: the 60-degree gloss retention (GR%) is 50 or more and less than 70 or the color difference (delta E) is 3.0 or more and less than 5.0.

X: the 60-degree gloss retention (GR%) is less than 50 and the color difference (delta E) is 5.0 or more.

[ Table 1 ]

TABLE 1

[ Table 2 ]

TABLE 2

[ Table 3 ]

TABLE 3 Table 3

In tables 1 to 3, the numerical values described for the respective components are solid content.

(note 1) the cartridge FM-3: epsilon-caprolactone modified vinyl monomer of 2-hydroxyethyl acrylate, trade name manufactured by WaxParacl chemical Co., ltd.

(note 2) the elastomer B-33: manufactured by Sakukukuai chemical Co., ltd., trade name, barium sulfate, and an average particle diameter of 0.03 μm

(note 3) late CR-95: trade name, titanium dioxide (note 4) BLUE RSK BE manufactured by lithopone corporation: DIC Co., ltd., trade name, copper phthalocyanine blue

(note 5) stron MA-100: trade name, carbon black manufactured by Mitsubishi chemical corporation

(note 6) K-WHITE 105: manufactured by texas corporation, trade name, aluminum dihydrogen tripolyphosphate (note 7) molecular sieve 5A (P): tacron Showa Co., ltd., trade name, calcium sodium aluminosilicate, pore diameter 0.42nm

(note 8) TINUVIN 400: manufactured by b.a.s.f., trade name, hydroxyphenyl triazine ultraviolet absorber

(note 9) a super N3300: takei コ, trade name, HDI isocyanurate

(note 10) critical D-102: sanjing chemical Co., ltd., trade name, polyisocyanate compound, TDI urethane polymer (urethane modified TDI)

(note 11) molecular sieve 3A: tacron Showa Co., ltd., trade name, calcium sodium aluminosilicate, pore diameter 0.25nm

(note 12) TINUVIN 477: manufactured by b.a.s.f., trade name, hydroxyphenyl triazine ultraviolet absorber

(Note 13) SPARWITE W-5HB: manufactured by Sino-Can Micronized Product co., ltd, trade name, barium sulfate, average particle diameter 1.6 μm

(Note 14) BARIFINE BF-20: manufactured by Sakukukuai chemical Co., ltd., trade name, barium sulfate, and an average particle diameter of 0.03 μm

(note 15) low-power 3N: manufactured by Bei Po powder industry Co., ltd., trade name, calcium carbonate, average particle diameter of 1.1 μm

(note 16) the optical SA-200: manufactured by bamboo chemical industry Co., ltd., trade name, calcium carbonate, and an average particle diameter of 0.08 μm

(note 17) slogan SL-700: manufactured by bamboo chemical industry Co., ltd., trade name, calcium carbonate, and an average particle diameter of 4.1 μm

(note 18) UVA 1130: manufactured by b.a.s.f., trade name, benzotriazole ultraviolet absorber

Although the present application has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. The present application is based on Japanese patent application (Japanese patent application No. 2021-36352) filed on 3/8 of 2021, the contents of which are incorporated herein by reference.

Industrial applicability

A coated article having a coating film excellent in corrosion resistance and weather resistance and also excellent in finished appearance can be provided.

Claims

1. A two-part coating composition comprising: a hydroxyl-containing acrylic resin (A), a polyisocyanate compound (B), zeolite (C) and a triazine ultraviolet absorber (D),

2. The two-part coating composition according to claim 1, wherein,

3. The two-part coating composition according to claim 1 or 2, wherein,

the zeolite (C) has a pore diameter of 0.5nm or less.

4. A construction machine or industrial machine coated with the two-component coating composition according to any one of claims 1 to 3.