AQUEOUS DISPERSION OF A POLYESTER AND A POLYAMIDE OF LOW ACID NUMBER AND COATING COMPOSITION COMPRISING SAME FOR APPLYING A BASECOAT

Abstract

The present invention relates to an aqueous dispersion (P) comprising at least one polymeric resin (P1) and at least one polymeric resin (P2) different therefrom, where the polymeric resin (P1) is a polyamide and the polymeric resin (P2) is a polyester which is at least obtainable by reaction of at least one polymerized aliphatic C.sub.12-C.sub.24 monocarboxylic acid with at least one diol and/or polyol, (P) being obtainable by dispersing of (P1) in water or an aqueous medium in the presence of (P2), and where (P1) has an acid number <10 mg of KOH per g of polyamide, and (P) contains at most 25 wt %, based on the total weight of (P), of one or more organic solvents, and also to an aqueous coating composition comprising (P), at least one binder (A) comprising at least one polymeric resin (A1), which is different from the polymeric resins (P1) and (P2), and at least one pigment (B) for at least partly coating a substrate with a basecoat film.

Claims

1: An aqueous dispersion (P) comprising at least one polymeric resin (P1) and at least one polymeric resin (P2) different therefrom, wherein the polymeric resin (P1) is a polyamide and the polymeric resin (P2) is a polyester, the aqueous dispersion (P) is obtained by dispersing the polymeric resin (P1) in water or an aqueous medium in the presence of the polymeric resin (P2), the polyamide used as polymeric resin (P1) has an acid number <10 mg of KOH per g of polyamide, the polyester as polymeric resin (P2) is obtained by reaction of at least one polymerized aliphatic C.sub.12-C.sub.24 monocarboxylic acid with at least one diol and/or polyol, and the aqueous dispersion (P) contains at most 25 wt %, based on the total weight of the dispersion (P), of one or more organic solvents.

2: The aqueous dispersion (P) as claimed in claim 1, which contains at most 20 wt %, based on the total weight of the dispersion (P), of one or more organic solvents.

3: The aqueous dispersion (P) as claimed in claim 1, wherein the polyamide as polymeric resin (P1) has an acid number in a range from 0.01 to 8.0 mg of KOH per g of polyamide.

4: The aqueous dispersion (P) as claimed in claim 1, wherein a relative weight ratio of polymeric resins (P2) and (P1) to one another, based in each case on their solids content, in the dispersion (P) is in a range from 10:1 to 1.5:1.

5: The aqueous dispersion (P) as claimed in claim 1, wherein the polyamide as polymeric resin (P1) is present in the dispersion (P) in an amount in a range from 0.5 to 15 wt %, based on the total weight of the dispersion (P).

6: The aqueous dispersion (P) as claimed in claim 1, wherein the polyester used as polymeric resin (P2) is present in the dispersion (P) in an amount in a range from 5 to 20 wt %, based on the total weight of the dispersion (P).

7: The aqueous dispersion (P) as claimed in claim 1, wherein the polyester as polymeric resin (P2) has an acid number in a range from 20 to 50 mg of KOH per g of polyester and/or a hydroxyl number in a range from 20 to 300 mg of KOH per g of polyester.

8: The aqueous dispersion (P) as claimed in claim 1, wherein the polyester as polymeric resin (P2) is obtained by reaction of at least one dimerized and/or trimerized aliphatic C.sub.12-C.sub.24-monocarboxylic acid with at least one aliphatic C.sub.2-C.sub.20 polyol and/or C.sub.2-C.sub.20 diol.

9: The aqueous dispersion (P) as claimed in claim 1, wherein the polyester used as polymeric resin (P2) is prepared additionally with at least one dicarboxylic acid and/or at least one tricarboxylic acid selected from the group consisting of aliphatic C.sub.3-C.sub.12 dicarboxylic acids, cycloaliphatic C.sub.5-C.sub.12 dicarboxylic acids, aromatic C.sub.8-C.sub.12-dicarboxylic acids, aliphatic C.sub.5-C.sub.12 tricarboxylic acids, cycloaliphatic C.sub.6-C.sub.12 tricarboxylic acids and aromatic C.sub.9-C.sub.12 tricarboxylic acids, and optionally additionally with at least one aliphatic C.sub.12-C.sub.24 monocarboxylic acid.

10: A method of making an aqueous coating composition, the method comprising: incorporating the dispersion (P) as claimed in claim 1 as a rheological assistant in an aqueous coating composition.

11: An aqueous coating composition comprising the aqueous dispersion (P) as claimed in claim 1, at least one binder (A) comprising at least one polymeric resin (A1), which is different from the polymeric resins (P1) and (P2), and optionally at least one crosslinking agent (A2), and at least one pigment (B), wherein the composition is configured for at least partly coating an optionally coated substrate with a basecoat film.

12: The coating composition as claimed in claim 11, which comprises the polyamide as polymeric resin (P) within the dispersion (P) in an amount in a range from 0.05 to 5 wt %, based on the total weight of the coating composition.

13: The coating composition as claimed in claim 11, wherein the binder (A) comprises at least one polyurethane and/or at least one poly(meth)acrylate and/or at least one polyester as at least one polymeric resin (A1).

14: The coating composition as claimed in claim 11, which comprises the polymeric resin (A1) in an amount in a range from 5 to 40 wt %, based on the total weight of the coating composition, and the pigment (B) in an amount in a range from 0.1 to 25 wt %, based on the total weight of the coating composition.

15: A substrate coated at least partly with the aqueous coating composition as claimed in claim 11.

16: The substrate of claim 15, wherein the substrate coated at least partly with the aqueous coating composition does not comprise bits, pinholes, and/or pops.

17: The aqueous dispersion (P) as claimed in claim 1, wherein the aqueous dispersion does not form two or more macroscopic phases after storage at 40° C. for 28 days.

Description

INVENTIVE AND COMPARATIVE EXAMPLES

[0189] Unless indicated otherwise, the amounts in parts are parts by weight, and the amounts in percent are percentages by weight, in each case.

1. Components Used

[0190] The components identified below and used for preparing the dispersions and coating compositions of the invention and also corresponding comparative dispersions or comparative coating compositions have the following meanings:

Disparlon® A6900-20X is a commercially available polyamide from Kusumoto Chemicals, Ltd (nonvolatile fraction: 20 wt %).
Disparlon® A650-20X is a commercially available polyamide from Kusumoto Chemicals, Ltd (nonvolatile fraction: 20 wt %).
Disparlon® A670-20M is a commercially available polyamide from Kusumoto Chemicals, Ltd. (nonvolatile fraction: 20 wt %).
Disparlon® F-9030 is a commercially available polyamide from Kusumoto Chemicals, Ltd. (nonvolatile fraction: 20 wt %).
Thixatrol® P220X-MF is a commercially available polyamide from Elementis Specialties, Inc. (nonvolatile fraction: 20 wt %, acid number: 5 mg KOH/g).
Luvotix® PA 20 XA is a commercially available polyamide from Lehmann & Voss & Co. (nonvolatile fraction: 20 wt %, acid number: 7 mg KOH/g).
Luvotix® AB is a commercially available polyamide from Lehmann & Voss & Co. (nonvolatile fraction: 100 wt %; acid number: 3 mg KOH/g).
Troythix® 250 XF is a commercially available polyamide from Troy Corp., USA (nonvolatile fraction: 20 wt %; acid number: 4-5 mg KOH/g).

[0191] The inventively employed aqueous dispersion of a polyester (I) is prepared as described in example D of DE 40 09 858 A1 (column 16, lines 37-59), but with the difference that butyl glycol is used for dilution instead of butanol, the dispersion having a nonvolatile fraction of 60 wt %. The polyester has an acid number of 30 mg of KOH/g polyester.

[0192] Polyester A (inventively employed polyester) is prepared by weighing out and melting, in a reactor equipped with a stirrer, a thermometer, and a packed column, 6.13 parts by weight of neopentyl glycol, 3.23 parts by weight of 1,6-hexanediol, 7.78 parts by weight of hexahydrophthalic anhydride, and 29.17 parts by weight of a polymeric fatty acid (dimer content at least 98 wt %, trimer content at most 2 wt %, monomer content at most traces) and also 11.07 parts by weight of the commercially available product Bisphenol A 4EO. These constituents are heated, with stirring, in a manner such that the column overhead temperature does not exceed 95° C. Esterification is continued at not more than 220° C. until an acid number of 8.5 mg KOH/g has been reached. After cooling has taken place to 100° C., 3.33 parts by weight of trimellitic anhydride are added, and esterification is continued at not more than 160° C. until an acid number of 30-35 mg KOH/g has been reached. After cooling to 90° C. has taken place, 2.8 parts by weight of dimethylethanol amine, 17.28 parts by weight of deionized water, and 19.21 parts by weight of butyl glycol are incorporated slowly with stirring. The product is a finely divided dispersion having a pH of 7.3-8.5, a nonvolatile fraction of 60 wt %, an acid number of 35.3 mg KOH/g, and an OH number of 54 mg KOH/g. This dispersion is used as it is as polyester A.

[0193] Polyester B (inventively employed polyester) is prepared by weighing out and melting, in a reactor equipped with a stirrer, a thermometer, and a packed column, 6.87 parts by weight of neopentyl glycol, 7.23 parts by weight of 1,6-hexanediol, 5.81 parts by weight of hexahydrophthalic anhydride, and 32.66 parts by weight of a polymeric fatty acid (dimer content at least 98 wt %, trimer content at most 2 wt %, monomer content at most traces) and also 5.03 parts by weight of dodecenylsuccinic anhydride. These constituents are heated, with stirring, in a manner such that the column overhead temperature does not exceed 95° C. Esterification is continued at not more than 220° C. until an acid number of 8.5 mg KOH/g has been reached. After cooling has taken place to 100° C., 3.31 parts by weight of trimellitic anhydride are added, and esterification is continued at not more than 160° C. until an acid number of 30-35 mg KOH/g has been reached. After cooling to 90° C. has taken place, 2.78 parts by weight of dimethylethanol amine, 17.19 parts by weight of deionized water, and 19.12 parts by weight of butyl glycol are incorporated slowly with stirring.

[0194] The product is a finely divided dispersion having a pH of 7.3-8.5, a nonvolatile fraction of 60 wt %, an acid number of 35.5 mg KOH/g, and an OH number of 56 mg KOH/g. This dispersion is used as it is as polyester B.

[0195] Polyester C (noninventively employed polyester) is prepared by introducing maleic anhydride (MAn, 2.48 mol), adipic acid (AD, 2.72 mol), and 1,6-hexanediol (HD, 7.01 mol) into a 4-liter reactor made from stainless steel and equipped with a column, a condenser, and a water separator. Subsequently, 3% of xylene was added as an entrainer, and 0.1% of methylhydroquinone (the percentage figures are based on the amount of MAn, AD and HD used). The resulting reaction mixture was heated under lean air over the course of 5 hours. Throughout the reaction time, the temperature of the reaction mixture does not exceed 230° C. When an acid number of 2 mg KOH/g, based on the oligoester, was reached the reaction mixture was cooled to 80° C. This was followed by the addition in situ of trimelletic anhydride (TMAn, 0.95 mol). Thereafter, heating took place slowly to 160° C., and this temperature was maintained until an acid number of 35 mg KOH/g, based on the resulting oligoester, was reached. After cooling to 80° C. had again taken place, dimethylethanolamine (DMEA, 0.77 mol) was added over a period of 30 minutes. This was followed by the addition of water to set a solids content of 25 wt %, over a period of 30 minutes. The resulting dispersion was stirred for a further hour at 80° C. and then cooled to 18-23° C. This dispersion is used as it is as polyester C. The alpha,omega-hydroxy-functionalized oligoester present in the dispersion has an OH number of 58 mg KOH/g, an acid number of 35 mg KOH/g, a number-average molecular weight of 3618 g/mol, and a weight-average molecular weight of 25 400 g/mol.

[0196] Resimene® HM 2608 is a commercially available melamine-formaldehyde resin from Ineos (nonvolatile fraction: 80-85 wt %).

[0197] Lipotin® A is a commercially available wetting and dispersing agent from Evonik Industries AG.

[0198] Lutensol® ON 60 and Lutensol® XP 70 are commercially available nonionic surface additives from BASF SE.

[0199] The soya lecithin used is a liquid product available commercially from Hanf & Nelles.

[0200] Alu Stapa Hydrolux® VP56450 is a commercially available aluminum pigment available from Altana-Eckart.

[0201] Rheovis® AS 1130 is a commercially available aqueous solution from BASF SE, containing 30 wt % of thickener based on an acrylic copolymer.

[0202] Pluriol® E300 is a commercially available polyethylene glycol from BASF SE.

[0203] Dispex® Ultra FA 4437 is a commercially available flow control assistant available from BASF SE.

[0204] Disparlon® AQ600 is a commercially available polyamide from Kusumoto Chemicals, Ltd (nonvolatile fraction: 20 wt %).

[0205] Disparlon® AQ630 is a commercially available polyamide from Kusumoto Chemicals, Ltd (nonvolatile fraction: 18 wt %).

[0206] The aqueous dispersion of at least one polymeric resin (I) is prepared as described on page 7, line 55 to page 8, line 23 of DE 44 37 535 A1.

[0207] The aqueous dispersion of at least one polymeric resin (II) is a dispersion of a poly(meth)acrylate resin having a nonvolatile fraction of 26-28 wt %.

2. Preparation of Inventive Aqueous Dispersions of Thickeners and of Corresponding Comparative Dispersions (Noninventive Dispersions)

2.1 Preparation of Noninventive Comparative Dispersions of Thickeners V1 to V14:

[0208] Introduced initially is at least one organic solvent and also optionally at least one neutralizing agent such as, for example, 2,4,7,9-tetramethyl-5-decynediol. Added with stirring to the resulting mixture, at a temperature of 15-25° C., is at least one of the aforementioned commercially available polyamides. Added to this mixture in succession or simultaneously and with stirring is an aqueous dispersion of a polyester (I) and deionized water. The resulting mixture is subsequently homogenized with stirring over a period of 10 minutes at the aforementioned temperature, by means of the Dispermat® LC30 instrument from VWA-Getzmann, Germany, at a peripheral speed of the stirring disk used of 15 to 20 m/s.

[0209] In this way, from the components listed in tables 1.1 and 1.2 below, the noninventive dispersions of thickeners V1 to V14 are obtained. The amounts figures in each case are in wt %, based on the total weight of the respective dispersion:

TABLE-US-00001 TABLE 1.1 Preparation of dispersions of the noninventive thickeners V1 to V9 Components V1 V2 V3 V4 V5 V6 V7 V8 V9 Isobutanol 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 Dimethylethanolamine  2.0  2.0  2.0  2.0  1.0  1.0  1.0 —  0.3 2,4,7,9-  3.0  3.0  3.0  3.0  3.0  3.0  3.0  3.0  3.0 tetramethyl-5- decynediol in butyl glycol (52 wt %) Disparlon ® 10.0 — — — — — — — — 6900-20X Disparlon ® — 10.0 — — 10.0 — — — — A650-20X Disparlon ® — — 10. 0 — — 10.0 — 10.0 10.0 A670-20M THIXATROL ® — — — 10.0 — — 10.0 — — P220X - MF Aqueous 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 dispersion of a polyester (I) Deionized 45.0 45.0 45.0 45.0 46.0 46. 0 46.0 47.0 46.7 water Fraction of a   2%   2%   2%   2%   2%   2%   2%   2%   2% polyamide (wt % solids) Fraction of 33.4% 33.4% 33.4% 33.4% 33.4% 33.4% 33.4% 33.4% 33.4% organic solvents (wt %)

TABLE-US-00002 TABLE 1.2 Preparation of dispersions of the noninventive thickeners V10 to V14 Components V10 V11 V12 V13 V14 Butyl glycol 20.0 20.0 20.0 20.0 20.0 Dimethylethanolamine  0.3  0.3  0.3  0.3  0.3 2,4,7,9-tetramethyl-5-  3.0  3.0  3.0  3.0  3.0 decynediol in butyl glycol (52 wt %) THIXATROL ® 10.0 — — — — P220X-MF Disparlon ® 6900-20X — 10.0 — — — Disparlon ® A670-20M — — 10.0 — — Disparlon ®F-9030 — — — 10.0 — Luvotix ® PA 20 XA — — — — 10.0 Aqueous dispersion of a 20.0 20.0 20.0 20.0 20.0 polyester (I) Deionized water 46.7 46.7 46.7 46.7 46.7 Fraction of polyamide   2%   2%   2%   3%   2% (wt % solids) Fraction of organic 33.4% 33.4% 33.4% 32.4% 33.4% solvents (wt %)

[0210] The noninventive comparative dispersions V1 to V14 each have an organic solvent content of >32 wt %, based on the total weight of the respective dispersion. V1 to V9 are isobutanol-based and V10 to V14 are butyl glycol-based.

2.2 Preparation of Noninventive Comparative Dispersions of Thickeners V15 to V17:

[0211] The components listed in table 1.3 below are stirred together in the stated order with stirring at a temperature of 15-25° C. in each case to give a mixture. This mixture is subsequently homogenized with stirring for 10 minutes, in each case at the temperature stated above. The homogenization is carried out as described above in section 2.1.

TABLE-US-00003 TABLE 1.3 Preparation of dispersions of the noninventive thickeners V15 to V17 Components V15 V16 V17 Resimene ® HM 2608 24.20 24.68 24.20 Dimethylethanolamine  0.32  0.57  0.32 Disparlon ® A670-20M 19.11 — 19.11 Luvotix ® AB —  3.56 — n-Butoxypropanol 10.51 — 10.51 1-Propoxy-2-propanol 14.01 — 14.01 Isobutanol 15.29 — 15.29 Butyl glycol — 37.97 — Aqueous dispersion of a 16.56 33.22 — polyester (I) Fraction of polyamide (wt %   4%   4%   5% solids) Fraction of organic solvents 60.9% 47.2% 69.0% (wt %)

[0212] The noninventive comparative dispersions V15 to V17 each have an organic solvent content of >47 wt %, based on the total weight of the respective dispersion.

2.3 Preparation of Inventive Dispersions of Thickeners X1 to X7:

[0213] The components listed in table 1.4 below are stirred together in the stated order with stirring at a temperature of 15-25° C. in each case to give a mixture. This mixture is subsequently homogenized with stirring over a time of 10 minutes in each case at the temperature stated above. The homogenization is carried out as described above in section 2.1.

TABLE-US-00004 TABLE 1.4 Preparation of dispersions of inventive thickeners X1 to X7 Components X1 X2 X3 X4 X5 X6 X7 Aqueous dispersion of 22.50 22.50 22.50 10.00 10.00 — — a polyester (I) Polyester A — — — — — 23.60 — Polyester B — — — — — — 23.20 Dimethylethanolamine  0.45  0.45  0.45  0.30  0.30  0.45  0.45 2,4,7,9-Tetramethyl-5-  3.00  3.00  3.00 — —  3.00  3.00 decynediol in butyl glycol (52 wt %) Lipotin ® A  3.00  3.00 — — —  3.00  3.00 Soya lecithin — —  3.00 — — — — Lutensol ® ON 60 — — —  0.20 — — — Lutensol ® XP 70 — — — —  0.20 — — Deionized water 56.05 56.05 56.05 69.50 69.50 54.95 55.35 Disparlon ® A670-20M 15.00 — 15.00 10.00 10.00 15.00 15.00 Troythix ® 250XF — 15.00 — — — — — Butyl glycol — — — 10.00 10.00 — — Fraction of polyamide   3%   3%   3%   2%   2%   3%   3% (wt % solids) Fraction of organic 17.9% 17.9% 17.9% 20.0% 20.0% 18.5% 18.3% solvents (wt %)

2.4 Preparation of an Inventive Dispersion of Thickener X8 and of a Noninventive Dispersion of a Thickener V18:

[0214] The components listed in table 1.5 below are stirred together in the stated order with stirring at a temperature of 15-25° C. in each case to give a mixture. This mixture is subsequently homogenized with stirring over a time of 10 minutes in each case at the temperature stated above. The homogenization is carried out as described above in section 2.1.

TABLE-US-00005 TABLE 1.5 Preparation of a dispersion of inventive thickener X8 and of a noninventive thickener V18 Components X8 V18 Aqueous dispersion of a 10.0 — polyester (I) Polyester C — 14.5 Dimethylethanolamine 0.15 0.15 Disparlon ® A670-20M 5.0 5.0 Deionized water 15.0 15.0 Fraction of polyamide   3%   3% (wt % solids) Fraction of organic 19.9% 11.5% solvents (wt %)

2.5 Preparation of Noninventive Comparative Dispersions of Thickeners V19 and V20:

[0215] The components listed in table 1.6 below are stirred together in the stated order with stirring at a temperature of 15-25° C. in each case to give a mixture. This mixture is subsequently homogenized with stirring over a time of 10 minutes in each case at the temperature stated above. The homogenization is carried out as described above in section 2.1.

TABLE-US-00006 TABLE 1.6 Preparation of noninventive comparative dispersions of thickeners V19 and V20 Components X1 V19 V20 Aqueous dispersion of a 22.50 22.50 22.50 polyester (I) Dimethylethanolamine  0.45  0.45  0.45 2,4,7,9-Tetramethyl-5-  3.00  3.00  3.00 decynediol in butyl glycol (52 wt %) Lipotin ® A  3.00  3.00  3.00 Deionized water 56.05 56.05 54.35 Disparlon ® A670-20M 15.00 — — Disparlon AQ600 — 15.00 — Disparlon AQ630 — — 16.70 Fraction of polyamide   3%   3%   3% (wt % solids) Fraction of organic 17.9% 7.0% 7.6% solvents (wt %)

[0216] Since V19 and V20 represent comparative dispersions relative to X1, X1 is individualized again in table 1.6 for greater ease of reference.

3 Preparation of Inventive Coating Compositions and Comparative Coating Compositions

3.1 General Operating Procedure for Producing Inventive Coating Compositions and Comparative Coating Compositions:

[0217] The components listed under “aqueous phase” in each of the tables below are stirred together in the order stated to form an aqueous mixture M1. In the next step an organic mixture M2 is prepared from the components listed under “organic phase” in the tables below. The organic M2 mixture is added to the aqueous mixture M1. The combined mixture is then stirred for 10 minutes and adjusted, using deionized water and dimethylethanolamine, to a pH of 8 and to a spray viscosity of 85±5 mPa.Math.s under a shearing load of 1000 s.sup.−1 as measured with a rotary viscometer (Rheolab QC instrument with C-LTD80/QC conditioning system from Anton Paar) at 23° C.

[0218] Where one of the tables below additionally includes the further heading “Mixing varnish”, the components listed under that heading are each stirred together in the stated order first of all in order to prepare this mixing varnish, which is mixed at a temperature of 15 to 25° C. over a time of 10 minutes, and this mixing varnish is then added to the organic mixture M2. When the resulting mixture of mixing varnish and organic mixture M2 has been stirred over a time of 10 minutes at a temperature of 15 to 25° C., the resulting mixture is then added to the aqueous mixture M1, and the further procedure is as described above.

[0219] The respective quantity figures in each of the tables below represent wt % in each case, based on the total weight of the respective composition.

3.2 Coating Compositions V-I (Noninventive) and B-X6 and B-X7 (Inventive)

[0220]

TABLE-US-00007 TABLE 2.1 Preparation of B-X6 and B-X7 and also of V-I B-X6 B-X7 V-I Aqueous phase Deionized water 17.40 17.40 30.35 n-Butoxypropanol 1.90 1.90 1.90 2-Ethylhexanol 1.70 1.70 1.70 Dispersion of thickener 23.10 — — X6 Dispersion of thickener — 23.10 — X7 Disparlon ® A670-20M — — 3.47 Aqueous dispersion of at 24.25 24.25 24.25 least one polymeric resin (II) Aqueous dispersion of a — — 5.20 polyester (I) 1-Propoxy-2-propanol 2.55 2.55 2.55 Butyl glycol 0.70 0.70 0.70 Dimethylethanolamine in 0.70 0.70 0.80 water (10 wt %) Rheovis ® AS 1130 0.90 0.90 0.90 Resimene ® HM 2608 4.40 4.40 4.40 Pluriol P900 1.15 1.15 1.15 Aqueous dispersion of at 3.45 3.45 3.45 least one polymeric resin (II) Organic phase Alu Stapa Hydrolux ® 5.8 5.8 5.8 VP56450 Butyl glycol 6.2 6.2 6.2 Aqueous dispersion of at 5.8 5.8 5.8 least one polymeric resin (II)

3.3 Coating Compositions V-II and V-III (Noninventive) and B-X1 (Inventive)

[0221]

TABLE-US-00008 TABLE 2.2 Preparation of V-II and V-III and also of B-X1 V-II B-X1 V-III Aqueous phase Aqueous solution of an Na—Mg 26.70 — — phyllosilicate (3 wt % in deionized water) Deionized water 7.75 16.48 29.34 Butyl glycol 5.78 5.78 — Dispersion of thickener X1 — 22.96 — Disparlon ® A670-20M — — 3.44 Aqueous dispersion of at least one 32.26 32.26 — polymeric resin (II) Aqueous dispersion of a polyester 5.17 — 5.17 (I) Dimethylethanolamine in water 1.32 0.80 0.91 (10 wt %) Rheovis ® AS 1130 0.86 0.75 — 2,4,7,9-Tetramethyl-5-decynediol 0.70 — 0.69 in butyl glycol (52 wt %) Resimen ® HM 2608 4.36 4.36 — Pluriol ® P900 0.34 1.15 — Organic phase Butyl glycol 6.89 6.89 6.89 Alu Stapa Hydrolux ® VP56450 5.74 5.74 5.74 Mixing varnish: Aqueous dispersion of at least one 1.89 1.89 1.89 polymeric resin (II) Deionized water 1.17 1.17 1.17 2,4,7,9-Tetramethyl-5-decynediol 0.24 0.24 0.24 in butyl glycol (52 wt %) Dispex ® Ultra FA 4437 0.10 0.10 0.10 Dimethylethanolamine in water 0.01 0.01 0.01 (10 wt %) Butyl glycol 0.60 0.60 0.60

4 Tests and Investigations

[0222] 4.1 Tests and Investigations into the Inventive Dispersions and Comparative Dispersions
4.1.1 The noninventive comparative dispersions of thickeners V1 to V14, each with an organic solvent content of >32 wt %, based on the total weight of the respective dispersion, are investigated and assessed by the methods described above for the incidence of bits, the homogeneity, and their storage stability.

[0223] The results are summarized in Table 3.1.

TABLE-US-00009 TABLE 3.1 V1 to V14 Homogeneity 2 Storage 3 stability Bittiness 1

[0224] From table 3.1 it can be seen that V1 to V14 each exhibit adequate homogeneity with no observed incidence of bits, but that these dispersions do exhibit an inadequate storage stability, given that separation, in the form of phase separation, occurs after a period of only about 2 weeks on storage at 18-23° C. as described within the method of determination.

4.1.2 The noninventive comparative dispersions of thickeners V15 to V17, each with an organic solvent content of >47 wt %, based on the total weight of the respective dispersion, are investigated and assessed by the methods described above for the incidence of bits, the homogeneity, and their storage stability.

[0225] The results are summarized in Table 3.2.

TABLE-US-00010 TABLE 3.2 V15 V16 V17 Homogeneity 1 1 1 Stability 3 3 5 Bittiness 1 1 1

[0226] From table 3.2 it can be seen that V15 to V17 each exhibit adequate homogeneity with no observed incidence of bits, but that these dispersions do exhibit an inadequate storage stability, given that separation, in the form of phase separation, occurs after a period of only several days on storage at 18-23° C. (in the case of V15 and V16) or after several hours on storage at 18-23° C. (in the case of V17) as described within the method of determination.

4.1.3 The inventive dispersions of thickeners X1 to X7, each with an organic solvent content of <20 wt %, based on the total weight of the respective dispersion, are investigated and assessed by the methods described above for the incidence of bits, the homogeneity, the water-miscibility, and their storage stability. For determination of the water-miscibility, X1 to X7 are each prepared by mixing the components stated in Table 1.4 in the order indicated therein, although, in accordance with the description of the method for determining the water-miscibility, half of the respective amount of deionized water indicated in Table 1.4 is used only as the last component in the preparation of X1 to X7 (in the case of X1, therefore, of the total of 56.05 parts by weight of deionized water, for example, 28.025 parts by weight are used only as a final component).

[0227] The results are summarized in Table 3.3.

TABLE-US-00011 TABLE 3.3 X1 X2 X3 X4 X5 X6 X7 Homogeneity 1 1 1 1 1 1 1 Water-miscibility: 1 1 1 1 1 1 1 Bittiness after 1 1 1.5 1.5 1.5 1 1 preparation after 14 days at 40° C. 1 1 1.5 2 2 1 1 after 28 days at 40° C. 1 1 1.5 2 2 1 1 after 42 days at 40° C. 1 1 1.5 2 2 1 1 Storage stability after 1 1 1 1 1 1 1 28 days at 40° C. after 365 days at 40° C. 1 n.d. 1 n.d n.d. n.d. n.d. n.d. = not determined

[0228] From table 3.3 it can be seen that X1 to X7 each have good homogeneity and water-miscibility with no, or only slight, observed incidence of bits. Moreover, all of dispersions X1 to X7 each display good storage stability on storage at 40° C. over a period of 28 days as described within the method of determination: no separation, or phase separation, was observed. Dispersions X1 and X3, moreover, were stored over a period of 365 days at 40° C. as described within the method of determination: even after this comparatively long time, there were no observations of separation or of phase separation.

4.1.4 The inventive dispersion of thickener X8 and the comparative dispersion V18 are investigated and assessed according to the methods described above and in relation to the incidence of bits, the homogeneity, and the water-miscibility. For the determination of the water-miscibility, V18 and X8 are each prepared by mixing the components stated in Table 1.5, in the order indicated therein, and, in accordance with the description of the method for determining the water-miscibility, the amount of deionized water indicated in Table 1.5 is used only as a final component in the preparation of V18 and X8, respectively.

[0229] The results are summarized in table 3.4.

TABLE-US-00012 TABLE 3.4 V18 X8 Homogeneity 5 1 Water- 5 1 miscibility Bittiness 5 1

[0230] From table 3.4 it can be seen that with V18, in contrast to X8, it is possible to achieve neither good homogeneity nor good water-miscibility. Moreover, a large number of bits were observed in the case of V18.

[0231] V18 comprises as its polyester component a polyester which has not been obtained by reaction of at least one polymerized aliphatic C.sub.12-C.sub.24 monocarboxylic acid with at least one diol and/or polyol: these results show that it is essential to the invention that the polyester employed in accordance with the invention is obtainable by such a reaction with participation of a polymerized aliphatic C.sub.12-C.sub.24 monocarboxylic acid.

4.1.5 The inventive dispersion of thickener X1 and the comparative dispersions V19 and V20 are investigated and assessed according to the methods described above in relation to the incidence of bits and the homogeneity.

[0232] The results are summarized in Table 3.5.

TABLE-US-00013 TABLE 3.5 X1 V19 V20 Homogeneity 1 1 1 Bittiness after 1 3-4 3-4 preparation after 14 days 1 3-4 3-4 at 40° C.

[0233] From Tab. 3.5 it can be seen that with V19 and V20, although good homogeneity can be achieved as with X1 as well, V19 and V20 nevertheless differ from X1 in that the incidence of a large number of bits after preparation and also after storage is observed. V19 and V20 comprise, as polyamides, polyamides of high acid number that are customarily used in aqueous compositions, specifically the commercially available products Disparlon® AQ600 (V19) and AQ630 (V20). This disadvantage is not observed in the case of X1.

4.2 Tests and Investigations into the Inventive Coating Compositions and Comparative Coating Compositions
4.2.1 Investigations into the Incidence of Pinholes and Bits

[0234] These investigations take place in accordance with the methods described above.

[0235] The results are summarized in tables 4.1 and 4.2.

TABLE-US-00014 TABLE 4.1 Results of the investigations into the incidence of pinholes Film thickness range Clearcoat wedge B-X6 B-X7 V-I 20-30 μm 0 0 n.m. 30-40 μm 0 0 n.m. 40-50 μm 0 0 n.m. Total 0 0 n.m.
n.m.=not measurable

TABLE-US-00015 TABLE 4.2 Results of the investigations into incidence of bits B-X6 B-X7 V-I Bits 1 1 5

[0236] As can be seen from table 4.1, the presence of the inventive dispersions X6 and X7 as a component of the aqueous basecoat materials B-X6 and B-X7 results in excellent pinhole robustness: no pinholes were observed. As can be seen from table 4.2, moreover, no bittiness at all was observed in the case of B-X6 and B-X7. In contrast, a large number of bits were observed in the case of comparative basecoat material V-I: the aqueous comparative basecoat material V-I contains the individual components used to prepare the dispersions of the invention, namely a polyester (aqueous dispersion of polyester (I)) and a polyamide (Disparlon® A670-20M), which, however, are not processed beforehand to form a dispersion according to the invention, but were instead incorporated directly, as separate components, into the comparative basecoat material V-I. In the case of V-I, moreover, on storage at 18-23° C., separation is observed after just a few 10 hours. For this reason, it is not possible to evaluate the pinhole test in the case of V-I.

4.2.2 Investigations into the Incidence of Bits and the Storage Stability

[0237] These investigations take place in accordance with the methods described above.

[0238] The results are summarized in tables 4.3 and 4.4.

TABLE-US-00016 TABLE 4.3 Results of the investigations into incidence of bits V-II B-X1 V-III Bits 1 1 5

TABLE-US-00017 TABLE 4.4 Results of the investigations into storage stability V-II B-X1 V-III Low-shear directly after 3013 3053 n.m. viscosity (1 s−.sup.1) preparation in mPa .Math. s after 2 weeks' 3819 3177 n.m. storage at 40° C. Change [%] 27 4 High-shear directly after 78 79 n.m. viscosity preparation (1000 s−.sup.1) after 2 weeks' 87 85 n.m. in mPa .Math. s storage at 40° C. Change [%] 11 6 n.m. = not measurable

[0239] As can be seen from table 4.3, there was no observable bittiness in the case of B-X1 and V-II (containing an Na—Mg phyllosilicate as thickener). In contrast, a large number of bits were observed in the case of comparative basecoat material V-III: the aqueous comparative basecoat material V-III contains the individual components used to prepare the dispersions of the invention, namely a polyester (aqueous dispersion of polyester (I)) and a polyamide (Disparlon® A670-20M), which, however, are not processed beforehand to form a dispersion according to the invention, but were instead incorporated directly, as separate components, into the comparative basecoat material V-III. In the case of V-III, on storage at 40° C., phase separation, or separation, is observed after just a few hours, namely that the inventively employed polyamide cannot be incorporated as it is into an aqueous basecoat material, but instead only in the form of an inventive aqueous dispersion. For this reason, and on account of a large number of bits which occurred in the case of comparative basecoat material V-III, determination of the low-shear and high-shear viscosities is not possible in the case of V-III. The waterborne basecoat materials V-II and B-X1, in contrast, are stable on storage at 40° C. and exhibit an acceptable shift in the high-shear and low-shear viscosities after 2 weeks of storage at 40° C., with the inventive waterborne basecoat material B-X1 exhibiting significant advantages over V-II (small changes) (cf. table) 4.4).

4.2.3 Investigations into the Cloudiness

[0240] This investigation takes place in accordance with the method described above. The inventive coating composition B-X1 and also the comparative coating composition V-II as waterborne basecoat material are applied to a steel panel coated as described within the method of determination. Subsequently, as described within the method, a clearcoat material is applied to the resulting respective basecoat films.

[0241] The results are summarized in Table 4.5.

TABLE-US-00018 TABLE 4.5 Results of the investigations into cloudiness V-II B-X1 Clouds viewed straight 4 2 on (80°) Clouds viewed at an 4 3 angle (40°)

[0242] The results show that the inventive coating composition B-X1 in comparison to V2 has substantially lower cloudiness.