CN115315489A

CN115315489A - Water-based base paint composition

Info

Publication number: CN115315489A
Application number: CN202180023547.1A
Authority: CN
Inventors: 刘淑真; 石烈; S·P·Y·吴
Original assignee: BASF Coatings GmbH
Current assignee: BASF Coatings GmbH
Priority date: 2020-03-23
Filing date: 2021-03-17
Publication date: 2022-11-08
Also published as: WO2021191015A1; JP2023518604A

Abstract

The invention provides an aqueous base coat composition, which comprises: (A) A water soluble or dispersible film forming resin selected from the group consisting of polyurethane resins, acrylic resins, and combinations thereof; (B) a curing agent; and (C) an organic solvent comprising (C1) at least one ether with a boiling point of at least 200 ℃ selected from alkyl or aryl ethers of polyols; and (C2) at least one hydrophilic diol having a molecular weight of less than 400 g/mol. Also provided is the use of the aqueous basecoat composition in an automotive paint.

Description

Water-based base paint composition

Technical Field

The present invention relates to an aqueous basecoat composition comprising an organic solvent, and also to the use of the aqueous basecoat composition in automotive paints.

Background

Aqueous automotive paints have been developed for many years and become increasingly attractive as public awareness of environmental protection increases and environmental regulations become more stringent. To obtain an acceptable water-borne automotive paint, several considerations are required, such as paint applicability, film appearance and properties after paint cure, and the like.

In current automotive OEM (original equipment manufacturer) painting processes, the paint film appearance on the sill part is relatively worse than that of the automotive body part. The reason for this is mainly because the method includes a protective step, i.e. sealing and baking the underbody before painting in the paint booth, and the cooling of the threshold parts cannot be as fast as the bodywork parts. The higher temperature (30-35 ℃) of the threshold part results in a much poorer film appearance (e.g. gloss) obtained from the same lacquer.

Accordingly, it is still desirable to provide an aqueous automotive paint which is capable of overcoming the above-mentioned problems while providing a film having a good overall appearance not only on the sill part but also on the body part.

Summary of The Invention

In one aspect, the present invention provides an aqueous basecoat composition comprising:

(A) A water soluble or dispersible film forming resin selected from the group consisting of polyurethane resins, acrylic resins, and combinations thereof;

(B) A curing agent; and

(C) An organic solvent comprising:

(C1) At least one ether having a boiling point of at least 200 ℃ selected from alkyl or aryl ethers of polyhydric alcohols; and

(C2) At least one hydrophilic diol having a molecular weight of less than 400 g/mol.

In another aspect, the present invention provides the use of the aqueous basecoat composition of the present invention in an automotive paint, preferably an automotive Original Equipment Manufacturer (OEM) paint.

It has been surprisingly found that by using the aqueous basecoat composition of the present invention, the film appearance (e.g., smoothness and gloss) on an automotive rocker part is significantly improved. It has also been found that by using the aqueous basecoat composition of the present invention, the film appearance (e.g., smoothness) on automotive body parts is improved.

Detailed Description

It is to be understood that the present invention may be embodied in various forms and should not be limited to the embodiments described herein. Unless otherwise specifically indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In this context, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

(A) Water-soluble or dispersible film-forming resins

As the water-soluble or dispersible film-forming resin to be used in the aqueous base coat composition of the present invention, there may be mentioned any of the polyurethane resins, acrylic resins and combinations thereof known in the art to be useful in aqueous coating compositions.

Suitable polyurethane resins are generally polyaddition products of organic compounds having at least two reactive hydrogen functions and polyisocyanates, for example in the form of aqueous dispersions.

Organic compounds having at least two reactive hydrogen functional groups are well known in the art, such as polyols. Examples of polyols include, but are not limited to, those described in US6384131B1, namely:

polyols, such as saturated and unsaturated polyols, including ethylene glycol, propylene glycol, neopentyl glycol, 1, 4-butanediol, 1, 4-butenediol, 1, 6-hexanediol, furandimethanol and cyclohexanedimethanol;

polyester polyols formed from the reaction of saturated and unsaturated polyols (such as ethylene glycol, propylene glycol, neopentyl glycol, 1, 4-butanediol, 1, 4-butenediol, 1, 6-hexanediol, furandimethanol and cyclohexanedimethanol) with saturated and unsaturated polycarboxylic acids and derivatives thereof (such as maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, adipic acid, isophthalic acid, terephthalic acid, phthalic anhydride, dimethyl terephthalate, dimer acids and the like);

polyesters formed by reacting lactones (such as caprolactone) with polyols;

polyether polyols, for example polymerization products of cyclic oxides, such as ethylene oxide, propylene oxide or tetrahydrofuran;

-polyether polyols formed by the addition of one or more cyclic oxides onto water, ethylene glycol, propylene glycol, diethylene glycol, cyclohexanedimethanol, glycerol or bisphenol a;

polycarbonate polyols, for example the reaction products of 1, 3-propanediol, 1, 4-butanediol, 1, 6-hexanediol, diethylene glycol or tetraethylene glycol with diaryl carbonates, for example diphenyl carbonate, or phosgene;

polyacetal polyols, such as the reaction products of diols (e.g. diethylene glycol, triethylene glycol or hexanediol) with formaldehyde;

polyols, such as dihydroxy alkanoic acids including dimethylol propionic acid; and

-any mixture thereof.

Suitable polyisocyanates are also known in the art and may include aliphatic, cycloaliphatic and/or aromatic diisocyanates and polyisocyanates containing 3 or more isocyanate groups per molecule. Examples of the aliphatic diisocyanate may include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, propylene diisocyanate, ethyl ethylene diisocyanate, dimethyl ethylene diisocyanate, methyltrimethylene diisocyanate, and trimethylhexane diisocyanate. Examples of the alicyclic diisocyanate may include isophorone diisocyanate, cyclopentylene diisocyanate, and hydrogenation products of aromatic diisocyanates, such as cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, and dicyclohexylmethane diisocyanate. Examples of the aromatic diisocyanate may include benzene diisocyanate, toluene diisocyanate, xylene diisocyanate, biphenyl diisocyanate, naphthalene diisocyanate, and diphenylmethane diisocyanate or isomers or isomer mixtures thereof.

Preferably, the polyisocyanate is an aliphatic or cycloaliphatic diisocyanate. Isophorone diisocyanate is particularly preferred.

The polyurethane resin can be modified by introducing cation or anion modifying groups or potentially ionic groups which can be converted into cation and anion groups, so as to realize hydrophilic stabilization or improve the dispersibility in an aqueous medium. Such polyurethane resins are commonly referred to in the art as ionically hydrophilically stabilized polyurethane resins. Alternatively, the polyurethane resin may be modified by introducing a nonionic hydrophilic modifying group. Suitable cationic, anionic and/or nonionic modifications of polyurethane resins are known, for example, from WO2013/128011 A1.

The polyurethane resins useful in the aqueous basecoat compositions of the present invention may be those prepared by any method known in the art, or those commercially available.

Examples of commercially available polyurethane resins that can be used in the waterborne basecoat compositions of the present invention include those available from Allnex resins Germany GMBH

TW 1237/32WA and available from BASF (China) Company Ltd

PU 1035W。

Here, the acrylic resin is not particularly limited, and may be any of water-soluble or dispersible poly (meth) acrylates and modified poly (meth) acrylates. Suitable acrylic resins are typically hydroxyl-containing acrylic resins. The hydroxyl group-containing acrylic resin may be a copolymerization product of a hydroxyl group-containing polymerizable unsaturated monomer and at least one unsaturated monomer copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer, for example, in the form of an aqueous dispersion.

The hydroxyl-containing polymerizable unsaturated monomers are known in the art and may include, for example, monoesters of (meth) acrylic acid with glycols having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; epsilon-caprolactone modified compounds of monoesters of (meth) acrylic acid with glycols having 2 to 8 carbon atoms; n-methylol (meth) acrylamide; allyl alcohol; and (meth) acrylates having hydroxyl-terminated polyoxyethylene chains, as described in US9701866B 2.

The at least one unsaturated monomer copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer is not particularly limited and may be appropriately selected depending on the desired properties of the hydroxyl group-containing acrylic resin. Examples of the unsaturated monomer copolymerizable with the hydroxyl group-containing polymerizable unsaturated monomer may include, but are not limited to, those described in US9701866B2, that is:

alkyl or cycloalkyl (meth) acrylates such as 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 (meth) acrylate, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butyl cyclohexyl (meth) acrylate, cyclododecyl (meth) acrylate and tricyclodecyl (meth) acrylate;

isobornyl-containing polymerizable unsaturated monomers, such as isobornyl (meth) acrylate;

adamantyl-containing polymerizable unsaturated monomers, such as adamantyl (meth) acrylate; tricyclodecenyl-containing polymerizable unsaturated monomers, such as tricyclodecenyl (meth) acrylate;

polymerizable unsaturated monomers containing aromatic rings, such as benzyl (meth) acrylate, styrene, alpha-methylstyrene and vinyltoluene;

alkoxysilyl group-containing polymerizable unsaturated monomers, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, gamma- (meth) acryloyloxypropyltrimethoxysilane and gamma- (meth) acryloyloxypropyltriethoxysilane;

polymerizable unsaturated monomers containing fluorinated alkyl groups, such as perfluorobutylethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate and similar perfluoroalkyl (meth) acrylates; and fluorinated olefins and the like;

polymerizable unsaturated monomers having photopolymerizable functional groups, such as maleimides;

vinyl compounds, such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate and vinyl acetate;

polymerizable unsaturated monomers containing phosphoric acid groups, such as 2-acryloxyethyl phosphate, 2-methacryloxyethyl acid phosphate, 2-acryloxypropyl acid phosphate and 2-methacryloxypropyl acid phosphate;

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-diethylaminoethyl (meth) acrylate, N-dimethylaminopropyl (meth) acrylamide, methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, 2- (methacryloyloxy) ethyltrimethylammonium chloride, and addition products of glycidyl (meth) acrylate with amines;

polymerizable unsaturated monomers having at least two polymerizable unsaturated groups per molecule, such as allyl (meth) acrylate and 1, 6-hexanediol di (meth) acrylate;

epoxy-containing polymerizable unsaturated monomers, such as glycidyl (meth) acrylate, β -methylglycidyl (meth) acrylate, 3, 4-epoxycyclohexylmethyl (meth) acrylate, 3, 4-epoxycyclohexylethyl (meth) acrylate, 3, 4-epoxycyclohexylpropyl (meth) acrylate and allyl glycidyl ether;

-a (meth) acrylate having an alkoxy-terminated polyoxyethylene chain;

polymerizable unsaturated monomers containing sulfonic acid groups, such as 2-acrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl (meth) acrylate, allylsulfonic acid and 4-styrenesulfonic acid, and also the sodium or ammonium salts of these sulfonic acids;

polymerizable unsaturated monomers containing UV-absorbing functional groups, such as 2-hydroxy-4- (3-methacryloxy-2-hydroxypropoxy) benzophenone, 2-hydroxy-4- (3-acryloxy-2-hydroxypropoxy) benzophenone, 2 '-dihydroxy-4- (3-methacryloxy-2-hydroxypropoxy) benzophenone, 2' -dihydroxy-4- (3-acryloxy-2-hydroxypropoxy) benzophenone and 2- (2 '-hydroxy-5' -methacryloyloxyethylphenyl) -2H-benzotriazole;

Polymerizable unsaturated monomers containing carbonyl groups, e.g. acrolein, diacetone acrylamide, diacetone methacrylamideAmide, acetylethoxyethyl methacrylate, formylstyrene and C _4-7 Vinyl alkyl ketones (e.g., vinyl methyl ketone, vinyl ethyl ketone, and vinyl butyl ketone).

The hydroxyl group-containing acrylic resin has an acid value of preferably 1 to 200mg KOH/g, more preferably 2 to 180mg KOH/g.

The hydroxyl-containing acrylic resins useful in the aqueous basecoat compositions of the present invention may be those prepared by any method known in the art or may be commercially available.

Examples of commercially available hydroxyl-containing acrylic resins useful in the waterborne basecoat compositions of the present invention include those available from Allnex resins Germany GMBH

6160、

VSC 6800W/47WA and

VSC 6276W/44WA。

(B) Curing agent

As the curing agent, any compound capable of reacting with the water-soluble or dispersible film-forming resin (a) to cure the aqueous base coat composition of the present invention can be used. Examples of the curing agent (B) include amino resins, polyisocyanates, blocked polyisocyanates, epoxy group-containing compounds, carboxyl group-containing compounds and carbodiimide group-containing compounds, which may be used alone or in combination of two or more. Among these, amino resins, polyisocyanate compounds and blocked polyisocyanate compounds are preferable, and amino resins are particularly preferable.

Examples of suitable amino resins include partially or fully methylolated amino resins obtained by reacting an amino component (e.g., melamine, urea, benzoguanamine, acetoguanamine, steroidal guanamine, spiroguanamine, and dicyandiamide) with an aldehyde component (e.g., formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde). It is also possible to use methylolated amino resins in which at least part of the methylol groups have been alkylated with suitable alcohols, such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-ethylbutanol and 2-ethylhexanol.

As an example of an amino resin, a melamine resin may be particularly useful in the aqueous basecoat composition of the present invention. In particular, preference is given to methylated melamine resins obtained by etherification of at least part of the methylol groups of a partially or fully methylolated melamine resin with methanol; butylated melamine resin obtained by etherification of at least part of the methylol groups of a partially or fully methylolated melamine resin with butanol; methylated/butylated melamine resins obtained by etherification of at least part of the methylol groups of partially or fully methylolated melamine resins with methanol and butanol. Examples of commercially available amino resins that can be used in the aqueous basecoat compositions of the present invention include those available from Allnex USA inc

202、

203、

211、

251、

324、

325、

327、

350、

385、

1130、

1156、

1116、

1158; from Cytec Industries Inc

204、

238、

303、

323; and U-VAN available from Mitsui Chemicals, inc ^TM 120、U-VAN ^TM 20HS、U-VAN ^TM 20SE60、U-VAN ^TM 2021、U-VAN ^TM 2028 and U-VAN ^TM 28-60。

Examples of suitable polyisocyanates include aliphatic polyisocyanates such as trimethylene diisocyanate, 1, 2-propylene diisocyanate, tetramethylene diisocyanate, 2, 3-butylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 4-isocyanatomethyl-1, 8-octane diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, dodecamethylene diisocyanate, α' -dipropylether diisocyanate and vinylidene diisocyanate; alicyclic polyisocyanates such as 1, 3-cyclopentylene diisocyanate, 1, 2-cyclohexylene diisocyanate, 1, 4-cyclohexylene diisocyanate, 4-methyl-1, 3-cyclohexylene diisocyanate, 4' -dicyclohexylene diisocyanate-based methane, 3' -dimethyl-4, 4' -dicyclohexylene diisocyanate-based methane, norbornane diisocyanate and isophorone diisocyanate; aromatic polyisocyanates such as m-and p-phenylene diisocyanate, 1, 3-and 1, 4-bis (isocyanatomethyl) benzene, 1, 5-dimethyl-2, 4-bis (isocyanatomethyl) benzene, 1,3, 5-triisocyanatobenzene, 2, 4-and 2, 6-toluene diisocyanate, 2,4, 6-toluene triisocyanate, α, α, α ', α' -tetramethyl o-, m-, p-xylene diisocyanate, 4 '-biphenyl diisocyanatemethane, 4' -biphenyl diisocyanate, 3 '-dichloro-4, 4' -biphenyl diisocyanate and naphthalene-1, 5-diisocyanate; and any combination thereof.

Adducts of polyisocyanates, such as prepolymers of biurets, isocyanurates, allophanates, uretdiones, and polyisocyanates, can also be used as curing agents. Furthermore, (co) polymers of isocyanate functional monomers, such as α, α' -dimethyl m-isopropenyl benzyl isocyanate, may also be suitable.

Examples of suitable blocked polyisocyanates include the above-mentioned isocyanates and adducts thereof modified by blocking their isocyanate groups (-N-C = O groups) with a blocking agent. The blocking agent may be an oxime such as formamide oxime, acetamide oxime, acetoxime, methyl ethyl ketoxime, diacetyl monoxime, benzophenone oxime, and cyclohexane oxime; alcohols such as methanol, ethanol, propanol, butanol, pentanol, lauryl alcohol, benzyl alcohol, glycolic acid, methyl glycolate, ethyl glycolate, butyl glycolate, lactic acid, methyl lactate, ethyl lactate, butyl lactate, methylol urea, methylol melamine, diacetone alcohol, 2-hydroxyethyl acrylate, and 2-hydroxyethyl methacrylate; phenols such as phenol, cresol, xylenol, nitrophenol, ethylphenol, hydroxybiphenyl, butylphenol, isopropylphenol, nonylphenol, octylphenol, and methyl hydroxybenzoate; ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and methoxymethanol; lactams such as epsilon-caprolactam, delta-valerolactam, gamma-butyrolactam and beta-propiolactam; active methylene compounds such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate, and acetylacetone; mercaptans such as butyl mercaptan, t-butyl mercaptan, hexyl mercaptan, t-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol, methylthiophenol, and ethylthiophenol; amides such as acetanilide, acetyltoluidine, acrylamide, methacrylamide, acetic acid amide, stearic acid amide, and benzamide; imides such as succinimide, phthalimide and maleimide; amines, such as diphenylamine, phenylnaphthylamine; xylidine, N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine, dibutylamine, and butylphenyl amine; imidazole or an imidazole derivative; ureas such as urea, thiourea, ethylene urea, ethylene thiourea and diphenylurea; carbamates, such as phenyl N-phenyl carbamate; imines such as ethyleneimine and propyleneimine; sulfites such as sodium bisulfite and potassium bisulfite; and azoles, such as pyrazole or pyrazole derivatives.

(C) Organic solvent

It has surprisingly been found that paint films having a better appearance can be provided by using in an aqueous basecoat an organic solvent comprising (C1) at least one ether having a boiling point of at least 200 ℃ selected from alkyl or aryl ethers of polyols and (C2) at least one hydrophilic glycol having a molecular weight of less than 400 g/mol.

As ether (C1) it is possible to use any alkyl or aryl ether of a polyol having a boiling point of at least 200 ℃ and preferably a molecular weight of not more than 500 g/mol. More preferably alkyl or aryl ethers of polyols having a boiling point of 200-300 deg.c. Here, unless otherwise specified, the boiling point at each occurrence refers to the boiling point at a pressure of 1 atmosphere.

The alkyl or aryl ethers of the polyols may be the monoalkyl and dialkyl ethers of the polyols, the monoaryl and diaryl ethers of the polyols, especially the monoalkyl and dialkyl ethers of the diols, the monoaryl and diaryl ethers of the diols. Examples of alkyl or aryl ethers of polyols may include, but are not limited to, alkylene glycol monoalkyl ethers, alkylene glycol dialkyl ethers, alkylene glycol monoaryl ethers, alkylene glycol diaryl ethers, dialkylene glycol monoalkyl ethers, dialkylene glycol dialkyl ethers, dialkylene glycol monoaryl ethers, dialkylene glycol diaryl ethers, trialkylene glycol monoalkyl ethers, trialkylene glycol dialkyl ethers, trialkylene glycol monoaryl ethers, and trialkylene glycol diaryl ethers.

Suitable alkylene glycols from which the alkyl or aryl ethers of the polyols can be derived are, for example, selected from linear or branched C ₂ -C ₂₀ Alkylene glycols, preferably linear or branched C ₂ -C ₁₀ Alkylene glycols, especially linear or branched C ₂ -C ₆ An alkylene glycol. Examples of the alkylene glycol may include ethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, 1, 2-butylene glycol, 1, 3-butylene glycol, 2, 3-butylene glycol, 1, 4-butylene glycol, 2-methyl-1, 3-propylene glycol, 1, 2-pentanediol, 2, 3-pentanediol, 1, 4-pentanediol, 2, 4-pentanediol, 1, 5-pentanediol, neopentyl glycol (2, 2-dimethyl-1, 3-propanediol), 1, 4-hexanediol, 1, 5-hexanediol, 1, 6-hexanediol, 2, 5-hexanediol, 3-methyl-1, 5-pentanediol, 1, 8-octanediol, 1, 10-decanediol, 1, 12-dodecanediol, and 1, 18-octadecanediol.

Suitable dialkylene glycols from which alkyl or aryl ethers of polyols can be derived are, for example, di-C ₂ -C ₁₀ Alkylene glycols, preferably di-C ₂ -C ₆ Alkylene glycol, more preferably di-C ₂ -C ₄ An alkylene glycol.

Suitable trialkylene glycols from which alkyl or aryl ethers of polyols can be derived are, for example, tri-C ₂ -C ₆ Alkylene glycols, preferably tri-C ₂ -C ₄ An alkylene glycol.

The alkyl moiety in the alkyl ether of the polyol may be a straight or branched alkyl, preferably C ₁ -C ₂₀ Alkyl, more preferably C ₃ -C ₁₀ Alkyl, most preferably C ₄ -C ₈ An alkyl group.

The aryl moiety in the alkyl ether of the polyol may be, for example, unsubstituted or substituted phenyl, preferably phenyl and C ₁ -C ₁₀ Alkyl-substituted phenyl.

Preferred examples of the alkyl or aryl ether of the polyhydric alcohol may include, but are not limited to, diethylene glycol monobutyl ether (BDG), triethylene glycol monobutyl ether (BTG), diethylene glycol monoisobutyl ether (iddg), diethylene glycol monohexyl ether (HeDG), ethylene glycol mono 2-ethylhexyl Ether (EHG), diethylene glycol mono 2-ethylhexyl Ether (EHDG), ethylene glycol monophenyl ether (PhG), and diethylene glycol monophenyl ether (PhDG).

As the hydrophilic diol (C2), diols having an HLB value of at least 9 are suitable, and alkylene glycols and dialkylene glycols having an HLB value of at least 9 and a molecular weight of less than 400g/mol can be mentioned in particular. Here, unless otherwise specified, the HLB value at each occurrence refers to a value according to the Griffin method.

In particular, useful alkylene glycols may be selected from linear or branched C ₂ -C ₂₀ Alkylene glycols, preferably linear or branched C ₂ -C ₁₀ Alkylene glycols, especially straight-chain or branched C ₂ -C ₆ An alkylene glycol. Examples of the hydrophilic alkylene glycol may include, but are not limited to, ethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, 1, 2-butylene glycol, 1, 3-butylene glycol, 2, 3-butylene glycol, 1, 4-butylene glycol, 2-methyl-1, 3-propylene glycol, 1, 2-pentanediol, 2, 3-pentanediol, 1, 4-pentanediol, 2, 4-pentanediol, 1, 5-pentanediol, neopentyl glycol (2, 2-dimethyl-1, 3-propanediol), 1, 4-hexanediol, 1, 5-hexanediol, 1, 6-hexanediol, 2, 5-hexanediol, and 3-methyl-1, 5-pentanediol.

Useful dialkylene glycols may be selected from di-C ₂ -C ₁₀ Alkylene glycols, preferably di-C ₂ -C ₆ Alkylene glycol, more preferably di-C ₂ -C ₄ An alkylene glycol. Particularly suitable dialkylene glycols can be diethylene glycol, dipropylene glycol, or a combination thereof.

The ether (C1) and the hydrophilic diol (C2) may be used in a weight ratio of 5 to 2, preferably 2 to 1, more preferably 3 to 2.

The ether (C1) and the hydrophilic glycol (C2) may be included in the aqueous basecoat composition of the present invention in a total amount of from 1% to 8% by weight, preferably from 2% to 8% by weight, more preferably from 3% to 6% by weight, based on the weight of the aqueous basecoat composition.

It will be appreciated that the ether (C1) and hydrophilic glycol (C2) may be used in the presence of additional organic solvents conventionally used in aqueous basecoat compositions. In particular, the organic solvent (C) may comprise at least one organic solvent selected from the group consisting of: hydrocarbon solvents such as mineral spirits, toluene, xylene, and solvent naphtha; alcohol solvents other than the solvents (C1) and (C2), such as 1-hexanol, 1-octanol, 2-ethyl-1-hexanol and 1-decanol, benzyl alcohol; ester solvents such as n-butyl acetate, isobutyl acetate, isoamyl acetate and methyl amyl acetate; and ketone solvents such as methyl isobutyl ketone, cyclohexanone, ethyl-n-amyl ketone, and diisobutyl ketone.

The organic solvent (C) may be included in the aqueous base coat composition of the present invention in a total amount of 1 to 15% by weight, preferably 2 to 12% by weight, more preferably 3 to 10% by weight, based on the weight of the aqueous base coat composition.

The aqueous basecoat composition of the present invention further comprises color pigments such as white and black pigments, effect pigments, or combinations thereof. Suitable color pigments and effect pigments are known in the art and are described, for example, in

Lexikon Lacke und Druckfarben, georg Thieme Verlag, stuttgart, new York,1998, pages 176 and 451.

The aqueous basecoat composition optionally comprises at least one additional film-forming resin other than the water-soluble or dispersible film-forming resin (a). The at least one additional film-forming resin can be suitably selected by the person skilled in the art according to the actual requirements of the paint film.

As an example of the at least one additional film-forming resin, mention may be made of polyester resins, which may be esterification or transesterification products of carboxylic acids and/or carboxylic anhydrides with hydroxyl-containing compounds.

As suitable carboxylic acids, polycarboxylic acids having at least two carboxyl groups per molecule are generally used to prepare polyester resins. Examples of the polycarboxylic acid may include aliphatic polycarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, succinic acid, fumaric acid, maleic acid, and itaconic acid; aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4' -biphenyldicarboxylic acid, trimellitic acid and pyromellitic acid; alicyclic polycarboxylic acids such as tetrahydrophthalic acid, tetrahydroisophthalic acid, tetrahydroterephthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid and hexahydroterephthalic acid, which may be used alone or in combination of two or more.

Additionally or alternatively, the esterification or transesterification may be carried out using anhydrides of polycarboxylic acids. Anhydrides of the polycarboxylic acids described above, such as succinic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, phthalic anhydride, trimellitic anhydride and pyromellitic anhydride, can be used.

As a suitable hydroxyl group-containing compound, a polyol having two or more hydroxyl groups per molecule is generally used to prepare a polyester resin. Examples of the hydroxyl group-containing compound may include alkylene glycols such as ethylene glycol, propylene glycol, diethylene glycol, 1, 3-propanediol, triethylene glycol, tetraethylene glycol, dipropylene glycol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 2, 3-butanediol, 3-methyl-1, 2-butanediol, 2-butyl-2-ethyl-1, 3-propanediol, 1, 2-pentanediol, 1, 4-pentanediol, 1, 5-pentanediol, 2, 4-pentanediol, 2, 3-dimethyltrimethylene glycol, 3-methyl-4, 3-pentanediol, 3-methyl-1, 5-pentanediol, 2, 4-trimethyl-1, 3-pentanediol, 1, 6-hexanediol, 1, 5-hexanediol, 1, 4-hexanediol, 2, 5-hexanediol and neopentyl glycol; ester diols such as bis (hydroxyethyl) terephthalate; polyether glycols such as polyethylene glycol, polypropylene glycol and polybutylene glycol; trihydric or higher polyhydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, diglycerin, triglycerol, 1,2, 6-hexanetriol, pentaerythritol, dipentaerythritol, sorbitol, and mannitol, which may be used alone or in combination of two or more.

The hydroxyl group-containing polyester resin may be modified, for example, with a fatty acid, a monoepoxy compound, a polyisocyanate compound, or the like, during or after the preparation of the resin.

The hydroxyl-containing polyester resins useful in the aqueous basecoat compositions of the present invention may be those prepared by any method known in the art or commercially available.

As further examples of the at least one additional film-forming resin, mention may also be made of polyurethane resins and acrylic resins. At least one film-forming polyurethane and/or acrylic resin other than those which are water-soluble or dispersible film-forming resins (a) may be used as the at least one additional film-forming resin.

The aqueous basecoat composition of the present invention may also optionally comprise one or more hardening/curing catalysts, thickeners, surface modifiers, wetting agents, defoamers, plasticizers, fillers, coalescents, ultraviolet light absorbers, light stabilizers, antioxidants, and the like, as known to those skilled in the art.

The formulation of the aqueous base coat composition of the present invention is not particularly limited, and it may be in the form of a single component or a multi-component. In particular, the aqueous basecoat composition may be formulated according to conventional automotive aqueous basecoat formulations using an ether (C1) and a hydrophilic glycol (C2).

It will be appreciated that the aqueous basecoat composition of the present invention may already contain a total amount of aqueous medium so that an appropriate viscosity for painting purposes may be provided. The aqueous basecoat compositions of the invention may also be diluted to the appropriate viscosity prior to painting by adding more water and/or with the aid of small amounts of organic solvents.

There is no particular limitation on the method of preparing the aqueous basecoat composition of the present invention. Any method known in the art may be used, for example, kneading a mixture of the above-described resin and pigment, etc., and dispersing by a ball mill, sand mill, disperser, etc.

The aqueous basecoat composition of the present invention may be applied by any conventional coating method, such as air spray, air atomized electrostatic coating, bell cup atomized electrostatic coating, and the like, preferably after the preliminary application of a basecoat comprising an electrodeposition coating and/or sealant, such as in an automotive painting process.

In general, the waterborne base coat compositions of the present invention are applied in such a way that, after curing, a paint film having a thickness of from 5 to 100. Mu.m, preferably from 10 to 60 μm, is obtained and then cured, for example at a temperature of from 100 to 200 ℃, preferably from 120 to 180 ℃, for a suitable time, for example from 10 minutes to 1 hour, to obtain a cured paint film.

The invention will be further described by way of examples which are not intended to limit the scope of the invention.

Detailed description of the preferred embodiments

Embodiment 1. An aqueous basecoat composition comprising:

(B) A curing agent; and

(C) An organic solvent comprising:

Embodiment 2. The aqueous basecoat composition of embodiment 1, wherein the composition further comprises a pigment, preferably a white or black pigment.

Embodiment 3. The aqueous basecoat composition of any of embodiments 1-2, wherein the component (C1) is at least one selected from alkyl or aryl ethers of polyols having a boiling point of 200 to 300 ℃.

Embodiment 4. The aqueous basecoat composition of any of embodiments 1-3, wherein the component (C1) is at least one selected from alkyl or aryl ethers of polyols having a molecular weight of no more than 500 g/mol.

Embodiment 5. The aqueous basecoat composition of any of embodiments 1-4, wherein the component (C1) is at least one selected from the group consisting of monoalkyl and dialkyl ethers of polyols and monoaryl and diaryl ethers of polyols, preferably monoalkyl and dialkyl ethers of diols and monoaryl and diaryl ethers of diols.

Embodiment 6. The aqueous basecoat composition of any of embodiments 1-5, wherein the component (C1) is at least one selected from the group consisting of alkylene glycol monoalkyl ethers, alkylene glycol dialkyl ethers, alkylene glycol monoaryl ethers, alkylene glycol diaryl ethers, dialkylene glycol monoalkyl ethers, dialkylene glycol dialkyl ethers, dialkylene glycol monoaryl ethers, dialkylene glycol diaryl ethers, trialkylene glycol monoalkyl ethers, trialkylene glycol dialkyl ethers, trialkylene glycol monoaryl ethers, and trialkylene glycol diaryl ethers.

Embodiment 7 the aqueous basecoat composition of embodiment 6, wherein the alkylene glycol is selected from linear or branched C ₂ -C ₂₀ Alkylene glycols, preferably linear or branched C ₂ -C ₁₀ Alkylene glycol, more preferably straight-chain or branched C ₂ -C ₆ An alkylene glycol.

Embodiment 8. The aqueous basecoat composition of embodiment 6, wherein the dialkylene glycol is selected from di-C ₂ -C ₁₀ Alkylene glycols, preferably di-C ₂ -C ₆ Alkylene glycol, more preferably di-C ₂ -C ₄ An alkylene glycol.

Embodiment 9 the aqueous basecoat composition of embodiment 6, wherein the trialkylene glycol is selected from the group consisting of tri-C ₂ -C ₆ Alkylene glycols, preferably tri-C ₂ -C ₄ An alkylene glycol.

Embodiment 10. The aqueous basecoat composition of any of embodiments 6-9, wherein the alkyl groups of the alkyl ethers of the polyols are selected from linear or branched alkyl groups, preferably C ₁ -C ₂₀ Alkyl, more preferably C ₃ -C ₁₀ Alkyl, even more preferably C ₄ -C ₈ An alkyl group.

Embodiment 11 the aqueous basecoat composition of any of embodiments 6-9, wherein the aryl groups of the alkyl ethers of the polyols are selected from unsubstituted or substituted phenyl, preferably phenyl and C ₁ -C ₁₀ Alkyl-substituted phenyl.

Embodiment 12. The aqueous basecoat composition of any of embodiments 1-11, wherein the component (C1) is at least one selected from diethylene glycol monobutyl ether (BDG), triethylene glycol monobutyl ether (BTG), diethylene glycol monoisobutyl ether (iddg), diethylene glycol monohexyl ether (HeDG), ethylene glycol mono 2-ethylhexyl Ether (EHG), diethylene glycol mono 2-ethylhexyl Ether (EHDG), ethylene glycol monophenyl ether (PhG), and diethylene glycol monophenyl ether (PhDG).

Embodiment 13. The aqueous basecoat composition of any one of embodiments 1-12, wherein the hydrophilic diol has an HLB value of at least 9.

Embodiment 14. The aqueous basecoat composition of any of embodiments 1-13, wherein the component (C2) is selected from di-C ₂ -C ₁₀ Alkylene glycols, preferably di-C ₂ -C ₆ Alkylene glycol, more preferably di-C ₂ -C ₄ At least one alkylene glycol.

Embodiment 15 the aqueous basecoat composition of any one of embodiments 1-12, wherein the component (C2) is at least one selected from the group consisting of diethylene glycol and dipropylene glycol.

Embodiment 16. The aqueous basecoat composition of any one of embodiments 1 to 15, wherein the weight ratio of component (C1) to component (C2) is from 5 to 2, preferably from 2 to 1, more preferably from 3 to 2.

Embodiment 17. The aqueous basecoat composition of any one of embodiments 1 to 16, wherein the weight percentage of components (C1) and (C2) is from 1 to 8 weight percent, preferably from 2 to 8 weight percent, more preferably from 3 to 6 weight percent, based on the total weight of the aqueous basecoat composition.

Embodiment 18. The aqueous basecoat composition of any one of embodiments 1-17, wherein the composition comprises (a) 10 to 30 weight percent, on a solids content basis, of a film-forming resin; (B) 3-10% by weight, based on the solids content, of a curing agent; (C) 5-15 wt% of an organic solvent; (D) 0-5% by weight, based on the solids content, of an optional film-forming resin other than component (A); (E) 0.5 to 5% by weight of a black pigment; (F) 0-5 wt% of additives; and (G) 35 to 75 weight percent water, based on the total weight of the aqueous basecoat composition.

Embodiment 19. The aqueous basecoat composition of any of embodiments 1-17, wherein the composition comprises (a) 5 to 20 weight percent, on a solids basis, of a film-forming resin; (B) 1-5% by weight, based on the solids content, of a curing agent; (C) 5-15 wt% of an organic solvent; (D) 0-10% by weight, based on the solids content, of an optional film-forming resin other than component (A); (E) 20 to 35% by weight of a white pigment; (F) 0-5 wt% of additives; and (G) 35 to 60 weight percent water, based on the total weight of the aqueous basecoat composition.

Embodiment 20. Use of the aqueous basecoat composition of any one of embodiments 1-19 in an automotive paint, preferably an automotive Original Equipment Manufacturer (OEM) paint.

Examples

I. Preparation examples

EXAMPLE I.1 preparation of aqueous basecoat compositions (polar white)

Mixing 30 parts of polyurethane resin (A)

TW 1237/32WA from Allnex with a solids content of about 32% by weight), 50 parts of titanium dioxide (Ti 1237/32 WA)

R-706, from DuPont), 5 parts ethylene glycol monobutyl ether, 0.5 parts triethanolamine, and 14.5 parts deionized water were mixed and then milled to particle size D ₅₀ Not more than 10 μm, thereby obtaining a white pigment dispersion paste.

18 parts of a polyurethane resin (

TW 1237/32WA, obtained from Allnex, with a solids content of about 32% by weight), 5 parts of acrylic resin (

6160, from Allnex, solids content about 45% by weight), 45.5 parts of white pigment dispersion paste, 0.3 part of defoamer, 0.2 part of wetting agent and 27.5 parts of aqueous medium consisting of 22.5 parts of deionized water, 3 parts of triethylene glycol monobutyl ether (BTG) and 2 parts of Ethylene Glycol (EG) were introduced into a dispersion vessel and then dispersed to particle size D ₅₀ Not more than 10 μm. Subsequently, 3 parts of melamine resin (

203 from Allnex with a solids content of about 72% by weight) and 0.5 part of triethanolamine and stirred homogeneously to obtain a polar white paint PW-1.

Aqueous basecoat compositions PW-2 to PW-8 were prepared in the same manner based on the formulations shown in Table 1.

TABLE 1

¹ BDG: diethylene glycol monobutyl ether

² BTG (BTG): triethylene glycol monobutyl ether

³ EG: ethylene glycol

⁴ PG: propylene glycol

⁵ Defoaming agent:

104E from Evonik

⁶ Wetting agent:

347 from BYK

EXAMPLE I.2 preparation of aqueous basecoat compositions (jet black)

65 parts of a polyurethane resin (

TW 1237/32WA from Allnex with a solids content of about 32% by weight), 10 parts of carbon black (A)

1300 from Cabot), 10 parts diethylene glycol monobutyl ether, 1 part triethanolamine and 14 parts deionized water, and then ground to particle size D ₅₀ Not more than 8 μm, thereby obtaining a black pigment dispersionAnd (3) pasting.

35 parts of a polyurethane resin (

TW 1237/32WA, obtained from Allnex, with a solids content of about 32% by weight), 3 parts of acrylic resin (SETAQUA 6160, obtained from Allnex, with a solids content of about 45% by weight), 7 parts of black pigment dispersion paste, 0.3 part of defoamer and 49.2 parts of aqueous medium consisting of 44.2 parts of deionized water, 2.5 parts of triethylene glycol monobutyl ether (BTG) and 2.5 parts of Ethylene Glycol (EG) were introduced into a dispersion vessel and dispersed until the particle diameter D WAs reached ₅₀ Not exceeding 10 μm. Subsequently, 5 parts of melamine resin (

203 from Allnex with a solids content of about 72% by weight) and 0.5 part of triethanolamine and stirred homogeneously to obtain a dark black paint DB 1.

Aqueous basecoat compositions DB-2 to DB-7 were prepared in the same manner based on the formulations shown in Table 2.

TABLE 2

¹ BDG: diethylene glycol monobutyl ether

² BTG: triethylene glycol monobutyl ether

³ EG: ethylene glycol

⁴ PG: propylene glycol

⁵ Defoaming agent:

104E, from Evonik II. Working example

By electrodeposition, with cationic electrodeposition lacquers (

800, available from BASF coatings GmbH) to obtain a thickness of 11 μmThe paint film was dried and then baked at 175 ℃ for 25 minutes. In the following working examples, the obtained electrodeposition-coated sheet was used as a painted substrate (hereinafter referred to as ED sheet).

Example II.1 preparation and evaluation of polar white paint films

ED panels were painted with the polar white paint prepared in example I.1 using a rotary atomizer (EcoBell II, from Durr Systems AG, germany) (outflow rate 380 ml/min, rotation speed: 40000rpm, voltage: 60 kv) at a temperature of 23 ℃ and a humidity of 65% to give a dry film thickness of 29 μm. After painting, the panels were left to stand for 3 minutes and then flashed off at 80 ℃ for 10 minutes. After cooling to 23 ℃, clear lacquer(s) is applied

Obtained from BASF Coatings GmbH) to provide a dry film thickness of 50 μm. After painting, the panels were left to stand for 10 minutes and then baked horizontally at 140 ℃ for 30 minutes, thus obtaining final panels with a polar white paint film.

Another set of polar white paint films was prepared on ED panels according to the same method, except that baking was carried out with the panels placed vertically.

The polar white paint films obtained were evaluated by means of an orange peel meter (BYK 4840wave scan dual, from BYK Gardner GmbH) for Lw and Sw smoothness and DOI (distinctness of image) gloss in accordance with DIN EN ISO 2813. The results of the measurements are summarized in table 3.

TABLE 3

From the results shown in Table 3, it can be seen that the paint films obtained using the aqueous base coat compositions of the present invention (Nos. 1 to 4 and 9 to 12) have better smoothness (as indicated by the lower Lw value) while showing comparable gloss, compared with the paint films obtained by aqueous base coat compositions containing neither or only one of the organic solvents (C1) and (C2).

Example II.2 preparation and evaluation of a dark Black paint film

ED panels were painted with the dark black paint prepared in example I.2 using a rotary atomizer (EcoBell II, from Durr Systems AG, germany) (outflow rate 380 ml/min, rotation speed: 40000rpm, voltage: 60 kv) at a temperature of 23 ℃ and a humidity of 65% to give a dry film thickness of 15 μm. After painting, the panels were left to stand for 3 minutes and then flashed off at 80 ℃ for 10 minutes. After cooling to 23 ℃, clear lacquer(s) is applied

Obtained from BASF Coatings GmbH) to provide a dry film thickness of 50 μm. After painting, the panels were left to stand for 10 minutes and then baked horizontally at 140 ℃ for 30 minutes, so as to obtain the final panels with a dark black paint film.

The smoothness and gloss of the dark black paint film obtained were evaluated in the same manner as described in example ii.1. The results of the measurements are summarized in Table 4.

TABLE 4

From the results shown in Table 4, it can be seen that the paint films obtained using the aqueous base coat compositions of the invention (Nos. 17 to 20) have better smoothness (as indicated by the lower Lw value) while showing comparable gloss than the paint films obtained by aqueous base coat compositions containing no or only one of the organic solvents (C1) and (C2).

Example II.3 simulation of the commercial preparation of polar white paint films on threshold parts

The ED panels were heated to 55 ℃ and then, when the panels were at 50 ℃, painted with a polar white paint as prepared in example I.1 by means of a rotary atomizer (EcoBell II, from Durr Systems AG, germany) at an outflow rate of 380 ml/min, rotational speed: 40000rpm, voltage: 60kv, at a temperature of 23 ℃ and a humidity of 65%, to give a dry film thickness of 15 μm. After painting, the panels were left to stand for 3 minutes and then flashed off at 80 ℃ for 10 minutes. After cooling to 23 ℃, clear lacquer(s) is applied

Obtained from BASF Coatings GmbH) to provide a dry film thickness of 37 μm. After painting, the panels were left to stand for 10 minutes and then baked horizontally at 140 ℃ for 30 minutes, thus obtaining final panels with a polar white paint film.

The smoothness and gloss of the polar white paint film obtained were evaluated in the same manner as described in example ii.1. The results of the measurements are summarized in table 5.

TABLE 5

Example II.4 simulation of the commercial production of a deep black paint film on a threshold part

The ED panels were heated to 55 ℃ and then, when the panel temperature was 50 ℃, were painted with a dark black paint as prepared in example I.2 by means of a rotary atomizer (EcoBell II, from Durr Systems AG, germany) at an outflow rate of 380 ml/min, rotation speed: 40000rpm, voltage: 60kv, at a temperature of 23 ℃ and a humidity of 65%, to give a dry film thickness of 10 μm. After painting, the panels were left to stand for 3 minutes and then flashed off at 80 ℃ for 10 minutes. After cooling to 23 ℃, clear lacquer(s) is applied

Obtained from BASF Coatings GmbH) to provide a dry film thickness of 37 μm. After painting, the panels were left to stand for 10 minutes and then baked horizontally at 140 ℃ for 30 minutes, thereby obtaining the final panels with a dark black paint film.

The smoothness and gloss of the dark black paint films prepared were evaluated in the same way as described in example ii.1. The results of the measurements are summarized in Table 6.

TABLE 6

From the results shown in tables 5 and 6, it can be seen that the paint films obtained using the aqueous base paint compositions of the present invention (polar white nos. 24-27 and jet black nos. 32-35) have significantly improved smoothness and exhibit better gloss than the corresponding paint films obtained by aqueous base paint compositions containing neither or only one of the organic solvents (C1) and (C2). The aqueous basecoat composition of the present invention substantially prevents the loss of film gloss and smoothness due to elevated substrate temperatures prior to painting. It is expected that the paint film appearance on the rocker parts can be significantly improved by using the aqueous basecoat composition of the invention for automotive OEM painting.

Claims

1. An aqueous basecoat composition comprising:

(B) A curing agent; and

(C) An organic solvent comprising:

2. The aqueous basecoat composition of claim 1, wherein the composition further comprises a pigment, preferably a white or black pigment.

3. The aqueous base coat composition according to claim 1 or 2, wherein the component (C1) is at least one selected from alkyl or aryl ethers of polyhydric alcohols having a boiling point of 200 to 300 ℃.

4. The aqueous basecoat composition of any one of claims 1 to 3 wherein said component (C1) is at least one selected from alkyl or aryl ethers of polyols having a molecular weight of not more than 500 g/mol.

5. The aqueous basecoat composition of any one of claims 1 to 4, wherein the component (C1) is at least one selected from monoalkyl and dialkyl ethers of polyols and monoaryl and diaryl ethers of polyols, preferably monoalkyl and dialkyl ethers of diols and monoaryl and diaryl ethers of diols.

6. The aqueous basecoat composition of any of claims 1 to 5 wherein said component (C1) is at least one selected from the group consisting of alkylene glycol monoalkyl ethers, alkylene glycol dialkyl ethers, alkylene glycol monoaryl ethers, alkylene glycol diaryl ethers, dialkylene glycol monoalkyl ethers, dialkylene glycol dialkyl ethers, dialkylene glycol monoaryl ethers, dialkylene glycol diaryl ethers, trialkylene glycol monoalkyl ethers, trialkylene glycol dialkyl ethers, trialkylene glycol monoaryl ethers, and trialkylene glycol diaryl ethers.

7. The aqueous basecoat composition of claim 6 wherein said alkylene glycol is selected from linear or branched C ₂ -C ₂₀ Alkylene glycols, preferably linear or branched C ₂ -C ₁₀ Alkylene glycol, more preferably straight-chain or branched C ₂ -C ₆ An alkylene glycol.

8. The aqueous basecoat composition of claim 6 wherein said dialkylene glycol is selected from di-C ₂ -C ₁₀ Alkylene glycols, preferably di-C ₂ -C ₆ Alkylene glycol, more preferably di-C ₂ -C ₄ An alkylene glycol.

9. The aqueous basecoat composition of claim 6 wherein the trialkylene glycol is selected from tri-C ₂ -C ₆ Alkylene glycols, preferably tri-C ₂ -C ₄ An alkylene glycol.

10. The aqueous basecoat composition of any one of claims 6-9, wherein the alkyl groups in the alkyl ethers of polyols are selected from linear chainsOr branched alkyl, preferably C ₁ -C ₂₀ Alkyl, more preferably C ₃ -C ₁₀ Alkyl, even more preferably C ₄ -C ₈ An alkyl group.

11. The aqueous basecoat composition of any one of claims 6 to 9, wherein the aryl groups in the alkyl ethers of polyols are selected from unsubstituted or substituted phenyl groups, preferably phenyl and C ₁ -C ₁₀ Alkyl-substituted phenyl.

12. The aqueous basecoat composition of any one of claims 1 to 11, wherein the component (C1) is at least one selected from the group consisting of diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, ethylene glycol mono 2-ethylhexyl ether, diethylene glycol mono 2-ethylhexyl ether, ethylene glycol monophenyl ether, and diethylene glycol monophenyl ether.

13. The aqueous basecoat composition of any one of claims 1-12, wherein the hydrophilic glycol has an HLB value of at least 9.

14. The aqueous basecoat composition of any of claims 1 to 13 wherein said component (C2) is selected from di-C ₂ -C ₁₀ Alkylene glycols, preferably di-C ₂ -C ₆ Alkylene glycol, more preferably di-C ₂ -C ₄ At least one alkylene glycol.

15. The aqueous base coat composition according to any one of claims 1 to 12, wherein the component (C2) is at least one selected from diethylene glycol and dipropylene glycol.

16. The aqueous basecoat composition of any one of claims 1 to 15, wherein the weight ratio of component (C1) to component (C2) is from 5 to 2, preferably from 2 to 1, more preferably from 3 to 2.

17. The aqueous basecoat composition of any of claims 1 to 16, wherein the weight percentage of components (C1) and (C2) is from 1 to 8 weight percent, preferably from 2 to 8 weight percent, more preferably from 3 to 6 weight percent, based on the total weight of the aqueous basecoat composition.

18. Use of the aqueous basecoat composition of any one of claims 1 to 17 in an automotive paint, preferably an automotive Original Equipment Manufacturer (OEM) paint.