METHOD FOR PRODUCING A MULTI-LAYERED COATING

Abstract

Provided herein is a method for producing a multicoat paint system on a metallic substrate by producing a basecoat or a plurality of directly successive basecoats directly on a metallic substrate coated with a cured electrocoat system, producing a clearcoat directly on the one or the topmost of the plurality of basecoats, and subsequently jointly curing the one or the plurality of basecoats and the clearcoat, wherein at least one basecoat material used for producing the basecoats includes at least one aqueous dispersion which includes a polymer whose preparation includes successive radical emulsion polymerization of three mixtures of olefinically unsaturated monomers.

Claims

1. A method for producing a multicoat paint system (M) on a metallic substrate (S), comprising (1) producing a cured electrocoat (E.1) on the metallic substrate (S) by electrophoretic application of an electrocoat material (e.1) to the substrate (S) and subsequent curing of the electrocoat material (e.1), (2) producing (2.1) a basecoat (B.2.1) or (2.2) two or more directly successive basecoats (B.2.2.x) directly on the cured electrocoat (E.1) by (2.1) application of an aqueous basecoat material (b.2.1) directly to the electrocoat (E.1) or (2.2) directly successive application of two or more basecoat materials (b.2.2.x) to the electrocoat (E.1), (3) producing a clearcoat (K) directly on (3.1) the basecoat (B.2.1) or (3.2) on the topmost basecoat (B.2.2.x) by application of a clearcoat material (k) directly to (3.1) the basecoat (B.2.1) or (3.2) to the topmost basecoat (B.2.2.x), (4) jointly curing the (4.1) basecoat (B.2.1) and the clearcoat (K) or (4.2) the basecoats (B.2.2.x) and the clearcoat (K), and wherein the basecoat material (b.2.1) or at least one of the basecoat materials (b.2.2.x) comprises at least one aqueous dispersion (wD), the dispersion (wD) comprising at least one polymer having a particle size of 100 to 500 nm and produced by successive radical emulsion polymerization of three mixtures (A), (B), and (C) of olefinically unsaturated monomers, the mixture (A) comprising at least 50 wt % of monomers having a solubility in water of less than 0.5 g/l at 25 C., and a polymer prepared from the mixture (A) possessing a glass transition temperature of 10 to 65 C., the mixture (B) comprising at least one poly-unsaturated monomer, and a polymer prepared from the mixture (B) possessing a glass transition temperature of 35 to 15 C., and a polymer prepared from the mixture (C) possessing a glass transition temperature of 50 to 15 C., and i. first mixture (A) being polymerized, ii. then mixture (B) being polymerized in the presence of the polymer prepared under i., and iii. thereafter mixture (C) being polymerized in the presence of the polymer prepared under ii.

2. The method as claimed in claim 1, wherein the fraction of the monomer mixture (A) is from 0.1 to 10 wt %, the fraction of the monomer mixture (B) is from 60 to 80 wt %, and the fraction of the monomer mixture (C) is from 10 to 30 wt %, based in each case on the sum of the individual amounts of the mixtures (A), (B), and (C).

3. The method as claimed in claim 1, wherein the monomer mixture (A) comprises at least one monounsaturated ester of (meth)acrylic acid having an alkyl radical, and at least one monoolefinically unsaturated monomer containing vinyl groups and having, located on at least one vinyl group, a radical which is aromatic or which is mixed saturated-aliphatic-aromatic, in which case the aliphatic moieties of the radical are alkyl groups.

4. The method as claimed in claim 1, wherein the monomer mixture (B) comprises, in addition to the at least one polyolefinically unsaturated monomer, at least one monounsaturated ester of (meth)acrylic acid having an alkyl radical and at least one monoolefinically unsaturated monomer containing vinyl groups and having, located on at least one vinyl group, a radical which is aromatic or which is mixed saturated-aliphatic-aromatic, in which case the aliphatic moieties of the radical are alkyl groups.

5. The method as claimed in claim 1, wherein the monomer mixture (B) comprises, as polyolefinically unsaturated monomers, exclusively diolefinically unsaturated monomers.

6. The method as claimed in claim 1, wherein the monomer mixtures (A) and (B) comprise no hydroxy-functional monomers and no acid-functional monomers.

7. The method as claimed in claim 1, wherein the monomer mixture (C) comprises at least one alpha-beta unsaturated carboxylic acid, at least one monounsaturated ester of (meth)acrylic acid having an alkyl radical substituted by a hydroxyl group, and at least one monounsaturated ester of (meth)acrylic acid having an alkyl radical.

8. The method as claimed in claim 1, wherein metered addition of olefinically unsaturated monomers in stages i. to iii. is such that in the reaction solution a fraction of free monomers of 6.0 wt %, based on the total amount of the monomers used in the respective polymerization stage, is not exceeded throughout the reaction time.

9. The method as claimed in claim 1, wherein the basecoat material (b.2.1) or at least one of the basecoat materials (b.2.2.x) further comprises at least one further polymer as binder, selected from the group consisting of hydroxy-functional polyurethanes, polyesters, polyacrylates, and copolymers of these polymers.

10. The method as claimed in claim 1, wherein the basecoat material (b.2.1) or at least one of the basecoat materials (b.2.2.x) further comprises a melamine resin as crosslinking agent.

11. The method as claimed in claim 1, wherein the basecoat material (b.2.1) or at least one of the basecoat materials (b.2.2.x) comprises at least one color and/or effect pigment.

12. The method as claimed in claim 1, wherein the basecoat material (b.2.1) or at least one of the basecoat materials (b.2.2.x) is a one-component coating composition.

13. The method as claimed in claim 1, wherein the joint curing (4) is carried out at temperatures of 100 to 250 C. for a time of 5 to 60 min.

14. The method as claimed in claim 1, wherein the percentage sum of the solids content and the fraction of water of the basecoat material (b.2.1) or of at least one of the basecoat materials (b.2.2.x) is at least 70 wt %.

15. A multicoat paint system (M) produced by the method as claimed in claim 1.

16. The method as claimed in claim 9, wherein all of the basecoat materials (b.2.2.x) further comprise at least one further polymer as binder, selected from the group consisting of hydroxy-functional polyurethanes, polyesters, polyacrylates, and copolymers of these polymers.

17. The method as claimed in claim 10, wherein all of the basecoat materials (b.2.2.x) further comprise a melamine resin as crosslinking agent.

18. The method as claimed in claim 11, wherein all of the basecoat materials (b.2.2.x) comprise at least one color and/or effect pigment.

19. The method as claimed in claim 12, wherein all of the basecoat materials (b.2.2.x) are one-component coating compositions.

20. The method as claimed in claim 14, wherein the percentage sum of the solids content and the fraction of water of all of the basecoat materials (b.2.2.x) is 80 to 90 wt %.

Description

EXAMPLES

Description of Methods

[0250] 1. Solids Content (Nonvolatile Fraction)

[0251] The nonvolatile fraction is determined according to DIN EN ISO 3251 (date: June 2008). It involves weighing out 1 g of sample into an aluminum dish which has been dried beforehand, drying it in a drying oven at 125 C. for 60 minutes, cooling it in a desiccator and then reweighing it. The residue relative to the total amount of sample used corresponds to the nonvolatile fraction. The volume of the nonvolatile fraction may optionally be determined if necessary according to DIN 53219 (date: August 2009).

[0252] 2. Film Thicknesses

[0253] The film thicknesses are determined according to DIN EN ISO 2808 (date: May 2007), method 12A, using the MiniTest 3100-4100 instrument from ElektroPhysik.

[0254] 3. Assessment of the Incidence of Pops and Runs

[0255] To determine the propensity toward popping and running, in accordance with DIN EN ISO 28199-1 (date: January 2010) and DIN EN ISO 28199-3 (date: January 2010), multicoat paint systems are produced according to the following general protocol:

[0256] A perforated steel panel coated with a cured cathodic electrocoat (CEC) (CathoGuare 800 from BASF Coatings GmbH), with dimensions of 57 cm20 cm (according to DIN EN ISO 28199-1, section 8.1, version A) is prepared in analogy to DIN EN ISO 28199-1, section 8.2 (version A). Subsequently, in accordance with DIN EN ISO 28199-1, section 8.3, an aqueous basecoat material is applied in a single application electrostatically, in the form of a wedge, with a target film thickness (film thickness of the dried material) in the range from 0 m to 30 m. After a flashing time at 18-23 C. of 10 minutes (running test) or without a prior flashing time (popping test), the resulting basecoat is subjected to interim drying in a forced air oven at 80 C. for 5 minutes. In the case of the test for runs, the panels are flashed and interim-dried in a vertical position.

[0257] The determination of the popping limit, i.e., of the basecoat film thickness from which pops occur, is made according to DIN EN ISO 28199-3, section 5.

[0258] The determination of the running tendency is carried out according to DIN EN ISO 28199-3, section 4. As well as the film thickness at which a run exceeds a length of 10 mm from the bottom edge of the perforation, a determination is made of the film thickness above which an initial tendency to run can be observed visually at a perforation.

[0259] 4. Painting of Waterborne Basecoat Material Wedge Constructions

[0260] To assess the incidence of pinholes and also the flow as function of film thickness, wedge-format multicoat paint systems are produced in accordance with the following general protocols:

[0261] Variant A: First Waterborne Basecoat Material as Wedge, Second Waterborne Basecoat Material as Constant Coat

[0262] A steel panel with dimensions of 3050 cm, coated with a cured standard CEC (CathoGuare 800 from BASF Coatings), is provided with two adhesive strips (Tesaband adhesive tape, 19 mm) at one longitudinal edge, to allow determination of film thickness differences after coating.

[0263] The first waterborne basecoat material is applied electrostatically as a wedge with a target film thickness (film thickness of the dried material) of 0-30 m. After flashing at room temperature for 3 minutes, one of the two adhesive strips is removed and then the second waterborne basecoat material is applied likewise electrostatically in a single application. The target film thickness (film thickness of the dried material) is 13-16 m. After a further flashing time of 4 minutes at room temperature, the system is interim-dried in a forced air oven at 60 C. for 10 minutes. Following removal of the second adhesive strip, a commercial two-component clearcoat material (ProGloss from BASF Coatings GmbH) is applied by gravity-fed spray gun manually to the interim-dried system, with a target film thickness (film thickness of the dried material) of 40-45 m. The resulting clearcoat film is flashed at room temperature (18 to 23 C.) for 10 minutes; subsequently, curing takes place in a forced air oven at 140 C. for a further 20 minutes.

[0264] Variant B: First Waterborne Basecoat Material as Constant Coat, Second Waterborne Basecoat Material as Wedge

[0265] A steel panel with dimensions of 3050 cm, coated with a cured standard CEC (CathoGuard 800 from BASF Coatings), is provided with two adhesive strips (Tesaband adhesive tape, 19 mm) at one longitudinal edge, to allow determination of film thickness differences after coating.

[0266] The first waterborne basecoat material is applied electrostatically with a target film thickness (film thickness of the dried material) of 18-22 m. After flashing at room temperature for 3 minutes, one of the two adhesive strips is removed and then the second waterborne basecoat material is applied likewise electrostatically in a single application as a wedge. The target film thickness (film thickness of the dried material) is 0-30 m. After a further flashing time of 4 minutes at room temperature, the system is interim-dried in a forced air oven at 60 C. for 10 minutes. Following removal of the second adhesive strip, a commercial two-component clearcoat material (ProGloss from BASF Coatings GmbH) is applied by gravity-fed spray gun manually to the interim-dried system, with a target film thickness (film thickness of the dried material) of 40-45 m. The resulting clearcoat film is flashed at room temperature (18 to 23 C.) for 10 minutes; subsequently, curing takes place in a forced air oven at 140 C. for a further 20 minutes.

[0267] Variant C: One Waterborne Basecoat Material as Wedge

[0268] A steel panel with dimensions of 3050 cm, coated with a cured standard CEC (CathoGuard 800 from BASF Coatings), is provided with two adhesive strips (Tesaband adhesive tape, 19 mm) at one longitudinal edge, to allow determination of film thickness differences after coating.

[0269] The waterborne basecoat material is applied electrostatically as a wedge with a target film thickness (film thickness of the dried material) of 0-30 m. After a flashing time of 4 minutes at room temperature, the system is interim-dried in a forced air oven at 80 C. for 10 minutes.

[0270] Following removal of the adhesive strip, a commercial two-component clearcoat material (ProGloss from BASF Coatings GmbH) is applied by gravity-fed spray gun manually to the interim-dried waterborne basecoat film, with a target film thickness (film thickness of the dried material) of 40-45 m. The resulting clearcoat film is flashed at room temperature (18 to 23 C.) for 10 minutes; subsequently, curing takes place in a forced air oven at 140 C. for a further 20 minutes.

[0271] 5. Assessment of the Incidence of Pinholes

[0272] To assess the incidence of pinholes, multicoat paint systems are produced as per the methods for the painting of waterborne basecoat wedge systems (variant A and B, respectively), and are then evaluated visually according to the following general protocol:

[0273] The dry film thickness of the overall waterborne basecoat material system, consisting of the first and second waterborne basecoat materials, is checked and, for the basecoat film thickness wedge, the 0-20 m region and the region from 20 m to the end of the wedge are marked on the steel panel.

[0274] The pinholes are evaluated visually in the two separate regions of the waterborne basecoat wedge. The number of pinholes per region is counted. All results are standardized to an area of 200 cm.sup.2. In addition, optionally, a record is made of that dry film thickness of the waterborne basecoat material wedge from which pinholes no longer occur.

[0275] 6. Assessment of the Film Thickness-Dependent Leveling

[0276] To assess the film thickness-dependent leveling, multicoat paint systems are produced as per the methods for the painting of waterborne basecoat wedge systems (variant A, B, or C respectively), and are then evaluated visually according to the following general protocol:

[0277] The dry film thickness of the overall waterborne basecoat material system, consisting of the waterborne basecoat material or of the first and second waterborne basecoat materials, is checked and, for the basecoat film thickness wedge, the 15-20 m and also 20-25 m regions, or 10-15 m, 15-20 m, 20-25 m, 25-30 m, and, optionally, 30-35 m regions are marked on the steel panel.

[0278] The determination or assessment of the film thickness-dependent leveling takes place by means of the Wave scan instrument from Byk/Gardner within the four basecoat film thickness regions determined beforehand. For this purpose, a laser beam is directed at an angle of 60 onto the surface under investigation, and the fluctuations in the reflected light in the so-called short wave range (0.3 to 1.2 mm) and in the so-called long wave range (1.2 to 12 mm) are recorded by the instrument over a measuring distance of 10 cm (long wave=LW; short wave=SW; the lower the values, the better the appearance). Moreover, as a measure of the sharpness of an image reflected in the surface of the multicoat system, the instrument determines the characteristic variable distinctness of image (DOI) (the higher the value, the better the appearance).

[0279] 7. Assessment of the Film Thickness-Independent Leveling

[0280] To assess the film thickness-independent leveling, multicoat paint systems are produced according to the following general protocol:

[0281] The first waterborne basecoat material is applied electrostatically with a target film thickness (film thickness of the dried material) of 18 m to a steel panel with dimensions of 3050 cm, coated with a cured standard CEC (CathoGuare 800 from BASF Coatings). After a flashing time of 7 minutes 30 seconds at room temperature, the second waterborne basecoat material is applied electrostatically with a target film thickness of 12-13 m. After a further flashing time at room temperature of 4 minutes 30 seconds, the system is interim-dried in a forced air oven at 70 C. for 7 minutes 30 seconds.

[0282] Applied electrostatically to the interim-dried waterborne basecoat film is a commercial scratch-resistant two-component clearcoat material (Ceramiclear 5.1 from PPG) with a target film thickness (film thickness of the dried material) of 40-45 m. The resulting clearcoat film is flashed at room temperature for 8 minutes; subsequently, curing takes place in a forced air oven at 140 C. for a further 20 minutes. The leveling is captured metrically in accordance with the method described above (see Assessment of the film thickness-dependent leveling).

[0283] 8. Assessment of the Adhesion Properties after Condensation

[0284] To assess the adhesion properties after condensation, multicoat paint systems are produced according to the following general protocol:

[0285] The waterborne basecoat material is applied electrostatically with a target film thickness (film thickness of the dried material) of 18 m to a steel panel with dimensions of 3050 cm, coated with a cured standard CEC (CathoGuard 800 from BASF Coatings).

[0286] After a flashing time of 4 minutes at room temperature, the system is interim-dried in a forced air oven at 80 C. for 10 minutes.

[0287] Applied manually atop the interim-dried waterborne basecoat film using a gravity-fed spray gun is a commercial two-component clearcoat material (ProGloss from BASF Coatings GmbH) with a target film thickness (film thickness of the dried material) of 40-45 m. The resulting clearcoat film is flashed at room temperature (18 to 23 C.) for 10 minutes; subsequently, curing takes place in a forced air oven at 140 C. for a further 20 minutes.

[0288] The samples with the respective multicoat systems are then stored over a period of 10 days in a conditioning chamber under CH test conditions according to DIN EN ISO 6270-2:2005-09.

[0289] For the assessment of the technological properties of the multicoat systems, cross-cuts were carried out according to DIN EN ISO 2409 (rating GT 0 to GT 5; 0=best score; 5=worst score). The multicoat paint systems are assessed for stonechip adhesion in accordance with DIN EN ISO 20567-1, Method B. The assessment of the resulting damage is made likewise according to DIN EN ISO 20567-1. Furthermore, steam jet tests were carried out according to DIN 55662, Method B. The scratches (in a diagonal cross) were made with a Sikkens scratch needle (see DIN EN ISO 17872 Annex A). The assessment of the steam jet test results was carried out according to DIN 55662, and in particular the maximum width of the detachments in millimeters was ascertained.

[0290] Preparation of Aqueous Dispersions

[0291] The Preparation Protocol Described Below Refers to Table A.

[0292] Monomer Mixture (A), Stage i.

[0293] 80 wt % of items 1 and 2 from table A are introduced into a steel reactor (5 L volume) with reflux condenser and heated to 80 C. The remaining fractions of the components listed under Initial charge in table A are premixed in a separate vessel. This mixture and, separately from it, the initiator solution (table A, items 5 and 6) are added dropwise to the reactor simultaneously over the course of 20 minutes, the fraction of the monomers in the reaction solution, based on the total amount of monomers used in step i., not exceeding 6.0 wt % throughout the entire reaction time. Subsequently, stirring takes place for 30 minutes.

[0294] Monomer Mixture (B), Stage ii.

[0295] The components indicated under Mono 1 in table A are premixed in a separate vessel. This mixture is added dropwise to the reactor over the course of 2 hours, with the fraction of the monomers in the reaction solution, based on the total amount of monomers used in stage ii., not exceeding 6.0 wt % throughout the entire reaction time. Subsequently, stirring is carried out for 1 hour.

[0296] Monomer Mixture (C), Stage iii.

[0297] The components indicated under Mono 2 in table A are premixed in a separate vessel. This mixture is added dropwise to the reactor over the course of 1 hour, with the fraction of the monomers in the reaction solution, based on the total amount of monomers used in stage iii., not exceeding 6.0 wt % throughout the entire reaction time. Subsequently, stirring is carried out for 2 hours.

[0298] Thereafter the reaction mixture is cooled to 60 C. and the neutralizing mixture (table A, items 20, 21, and 22) is premixed in a separate vessel. The neutralizing mixture is added dropwise to the reactor over the course of 40 minutes, during which the pH of the reaction solution is adjusted to a value of 7.5 to 8.5. The reaction product is subsequently stirred for 30 minutes more, cooled to 25 C., and filtered.

TABLE-US-00001 TABLE A Aqueous dispersions BM2* BM3* BM4 BM5 BM6 BM7 Initial charge 1 DI water 41.81 41.81 41.81 41.81 41.81 41.81 2 EF 800 0.18 0.18 0.18 0.18 0.18 0.18 3 Styrene 0.68 0.93 0.93 0.93 0.23 0.23 4 n-Butyl 0.48 0.23 0.23 0.23 0.93 0.93 acrylate Initiator solution 5 DI water 0.53 0.53 0.53 0.53 0.53 0.53 6 APS 0.02 0.02 0.02 0.02 0.02 0.02 Mono 1 7 DI water 12.78 12.78 12.78 12.78 12.78 12.78 8 EF 800 0.15 0.15 0.15 0.15 0.15 0.15 9 APS 0.02 0.02 0.02 0.02 0.02 0.02 10 Styrene 5.61 5.61 12.41 12.41 12.41 12.41 11 n-Butyl 13.6 13.6 6.8 6.8 6.8 6.8 acrylate 12 1,6-HDDA 0.34 0.34 0.34 0.34 0.34 0.34 Mono 2 13 DI water 5.73 5.73 5.73 5.73 5.73 5.73 14 EF 800 0.07 0.07 0.07 0.07 0.07 0.07 15 APS 0.02 0.02 0.02 0.02 0.02 0.02 16 Methacrylic 0.71 0.71 0.71 0.71 0.71 0.71 acid 17 2-HEA 0.95 0.95 0.95 0.95 0.95 0.95 18 n-Butyl 3.74 1.87 3.74 1.87 3.74 1.87 acrylate 19 MMA 0.58 2.45 0.58 2.45 0.58 2.45 Neutralization 20 DI water 6.48 6.48 6.48 6.48 6.48 6.48 21 Butyl glycol 4.76 4.76 4.76 4.76 4.76 4.76 22 DMEA 0.76 0.76 0.76 0.76 0.76 0.76 *can be used as per the invention

[0299] The solids content was determined in order to monitor reaction. The results are reported in table B:

TABLE-US-00002 TABLE B Solids content of the aqueous dispersions BM2* BM3* BM4 BM5 BM6 BM7 Solids content [%] 25.5 25.5 25.5 26 27.4 26.1 *can be used as per the invention

[0300] After each stage and after the final neutralization, the particle size was determined. The results are reproduced in table C.

TABLE-US-00003 TABLE C Particle sizes in nanometers BM2* BM3* BM4 BM5 BM6 BM7 i After Initial 90 70 70 70 120 120 charge ii After Mono 1 150 160 160 180 150 160 iii After Mono 2 190 230 230 250 220 200 iiii After neutrali- 240 290 275 300 250 245 zation *can be used as per the invention

[0301] Each of the indicated monomer mixtures (A), (B), and (C) (corresponding to Initial charge, Mono 1 and Mono 2) was polymerized individually and the respective glass transition temperature of the polymer obtained was then determined. Additionally, the glass transition temperature was determined for the entire polymer after neutralization.

[0302] The results are reported in table D.

TABLE-US-00004 TABLE D Glass transition temperatures in C. BM2* BM3* BM4 BM5 BM6 BM7 i Initial charge 30 50 48 50 9 9 ii Mono 1 11 12 45 45 47 48 iii Mono 2 4 6 4 4 5 4 Entire polymer 9 7 46 47 45 46 *can be used as per the invention

[0303] Preparation of a Further Aqueous Dispersion BM8 (as Per Korea Polym. J., Vol. 7, No. 4, Pp. 213-222)

[0304] Components 1 to 4 from table E are introduced into a steel reactor (5 L volume) with reflux condenser and heated to 80 C. The initiator solution (table E, items 5 and 6) is added dropwise to the reactor over the course of 5 minutes. This is followed by stirring for 30 minutes.

[0305] The components indicated in table E under Mono 1 are premixed in a separate vessel. This mixture is added dropwise to the reactor over the course of 2 hours. This is followed by stirring for 1 hour.

[0306] The components indicated in table E under Mono 2 are premixed in a separate vessel. This mixture is added dropwise to the reactor over the course of 1 hour. This is followed by stirring for 1 hour.

[0307] Thereafter the reaction mixture is cooled to 60 C. and the neutralizing mixture (table E, items 21 and 22) is premixed in a separate vessel. The neutralizing mixture is added dropwise to the reactor over the course of 40 minutes. The reaction product is subsequently stirred for 30 minutes more and cooled to 25 C.

TABLE-US-00005 TABLE E Aqueous dispersion BM8 BM8 Initial charge 1 DI water 43.54 2 Rhodapex CO 436 0.16 3 Styrene 0.5 4 Ethyl acrylate 0.55 Initiator solution 5 DI water 0.55 6 APS 0.02 Mono 1 7 DI water 13.31 8 Rhodapex CO 436 0.13 9 APS 0.02 10 Styrene 5.84 11 Ethyl acrylate 11.05 12 1,6-HDDA 0.35 Mono 2 13 DI water 5.97 14 Rhodapex CO 436 0.06 15 APS 0.02 16 Methacrylic acid 0.74 17 2-HEA 0.99 18 Ethyl acrylate 3.04 19 MMA 0.6 Neutralization 20 DI water 6.75 21 Butyl glycol 4.96 22 DMEA 0.79 pH 8.1

[0308] The solids content was 23.4%.

[0309] After each stage and after the final neutralization, the particle size was determined. The results are reproduced in table F.

TABLE-US-00006 TABLE F Particle sizes in nanometers BM8 i After initial charge 110 ii After Mono 1 196 iii After Mono 2 223 iiii After neutralization 310

[0310] Each of the specified monomer mixtures was polymerized individually and the respective glass transition temperature of the polymer obtained was determined subsequently. In addition the glass transition temperature was determined for the entire polymer after neutralization.

[0311] The results are reported in table G.

TABLE-US-00007 TABLE G Glass transition temperatures in C. BM8 i Initial charge 32 ii Mono 1 26 iii Mono 2 35 Entire polymer 26

[0312] Preparation of Aqueous Basecoat Materials

[0313] The following should be taken into account regarding the formulation constituents and amounts thereof as indicted in the tables hereinafter. When reference is made to a commercial product or to a preparation protocol described elsewhere, the reference, independently of the principle designation selected for the constituent in question, is to precisely this commercial product or precisely the product prepared with the referenced protocol.

[0314] Accordingly, where a formulation constituent possesses the principal designation melamine-formaldehyde resin and where a commercial product is indicated for this constituent, the melamine-formaldehyde resin is used in the form of precisely this commercial product. Any further constituents present in the commercial product, such as solvents, must therefore be taken into account if conclusions are to be drawn about the amount of the active substance (of the melamine-formaldehyde resin).

[0315] If, therefore, reference is made to a preparation protocol for a formulation constituent, and if such preparation results, for example, in a polymer dispersion having a defined solids content, then precisely this dispersion is used. The overriding factor is not whether the principal designation that has been selected is the term polymer dispersion or merely the active substance, for example, polymer, polyester, or polyurethane-modified polyacrylate. This must be taken into account if conclusions are to be drawn concerning the amount of the active substance (of the polymer).

[0316] All proportions indicated in the tables are parts by weight.

[0317] 1.1a Preparation of a Noninventive Waterborne Basecoat Material WBM A1, of a Noninventive Waterborne Basecoat Material WBM A2, and of an Inventive Waterborne Basecoat Material WBM A3

[0318] The components listed under Aqueous phase in table 1.1a are combined with stirring in the order stated to form an aqueous mixture. This 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 90 mPa.Math.s under a shearing load of 1291 s.sup.1, as measured using a rotary viscometer (Rheolab QC instrument with C-LTD80/QC heating system from Anton Paar) at 23 C.

TABLE-US-00008 TABLE 1.1a Preparation of waterborne basecoat materials WBM A1 and WBM A2 (not inventive) and WBM A3 (inventive) Aqueous phase: WBM A1 WBM A2 WBM A3 3% strength Na Mg phyllosilicate 15.23 15.23 15.23 solution Deionized water 5.68 1-Propoxy-2-propanol 1.41 1.41 1.41 2-Ethylhexanol 0.87 0.87 0.87 Polyurethane-based graft copolymer; 26.51 prepared as per page 35, line 33 to page 36, line 22 (example D-B2) of WO 2015/007427 A1 Multistage acrylate, prepared as per 34.03 Korea Polym. J., Vol. 7, No. 4, pp. 213-222) (aqueous dispersion BM8) Aqueous dispersion (wD) BM2 31.23 Polyester; prepared as per page 28, 3.66 lines 13 to 33 (example BE1) of WO 2014/033135 A2 Polyester; prepared as per example D, 4.85 4.85 column 16, lines 37-59 of DE 40 09 858 A1 Melamine-formaldehyde resin (Cymel 5.44 5.44 5.44 203 from Allnex) 10% strength dimethylethanolamine in 0.55 0.30 0.30 water 2,4,7,9-Tetramethyl-5-decynediol, 52% 1.09 1.09 1.09 in BG (available from BASF SE) Triisobutyl phosphate 1.63 1.63 1.63 Polyurethane-modified polyacrylate; 2.91 2.91 2.91 prepared as per page 7, line 55 to page 8, line 23 of DE 4437535 A1 Butyl glycol 4.35 4.35 4.35 Isopar L, available from Exxon Mobil 1.84 1.84 1.84 Pluriol P900, available from BASF SE 0.54 0.54 0.54 Hydrosol A170, available from DHC Solvent Chemie GmbH 0.54 0.54 0.54 White paste 25.68 25.68 25.68 Black paste 1.53 1.52 1.52 Yellow paste 0.54 0.54 0.54

[0319] Preparation of the White Paste

[0320] The white paste is prepared from 50 parts by weight of titanium rutile 2310, 6 parts by weight of a polyester prepared as for example D, column 16, lines 37-59 of DE 40 09 858 A1, 24.7 parts by weight of a binder dispersion prepared as per patent application EP 022 8003 B2, page 8, lines 6 to 18, 10.5 parts by weight of deionized water, 4 parts by weight of 2,4,7,9-tetramethyl-5-decynediol, 52% in BG (available from BASF SE), 4.1 parts by weight of butyl glycol, 0.4 part by weight of 10% strength dimethylethanolamine in water, and 0.3 part by weight of Acrysol RM-8 (available from The Dow Chemical Company).

[0321] Preparation of the Black Paste

[0322] The black paste is prepared from 57 parts by weight of a polyurethane dispersion prepared as per WO 92/15405, page 13, line 13 to page 15, line 13, 10 parts by weight of carbon black (Monarch 1400 carbon black from Cabot Corporation), 5 parts by weight of a polyester prepared as per example D, column 16, lines 37-59 of DE 40 09 858 A1, 6.5 parts by weight of a 10% strength aqueous dimethylethanolamine solution, 2.5 parts by weight of a commercial polyether (Pluriol P900, available from BASF SE), 7 parts by weight of butyl diglycol, and 12 parts by weight of deionized water.

[0323] Preparation of the Yellow Paste

[0324] The yellow paste is prepared from 37 parts by weight of Bayferrox 3910 (available from Lanxess), 49.5 parts by weight of an aqueous binder dispersion prepared as per WO 91/15528, page 23, line 26 to page 25, line 24, 7.5 parts by weight of Disperbyk-184 (available from BYK-Chemie GmbH), and 6 parts by weight of deionized water.

[0325] 1.1b Preparation of a Noninventive Waterborne Basecoat Material WBM A4 and of an Inventive Waterborne Basecoat Material WBM A5

[0326] The components listed under Aqueous phase in table 1.1b are combined with stirring in the order stated to form an aqueous mixture. This 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 105 mPa.Math.s under a shearing load of 1000 s.sup.1, as measured using a rotary viscometer (Rheolab QC instrument with C-LTD80/QC heating system from Anton Paar) at 23 C.

TABLE-US-00009 TABLE 1.1b Preparation of waterborne basecoat materials WBM A4 (not inventive) and WBM A5 (inventive) Aqueous phase: WBM A4 WBM A5 Deionized water 14.60 13.00 2-Ethylhexanol 1.30 1.90 Aqueous binder dispersion; prepared as 9.00 per WO 92/15405, page 13, line 13 to page 15, line 13 Aqueous dispersion (wD) BM2 33.00 Polyester; prepared as per page 28, 1.00 3.00 lines 13 to 33 (example BE1) of WO 2014/033135 A2 Polyester; prepared as per example D, 4.50 column 16, lines 37-59 of DE 40 09 858 A1 Melamine-formaldehyde resin (Cymel 7.20 8.50 203 from Allnex) 10% strength dimethylethanolamine in 0.90 0.40 water Triisobutyl phosphate 1.00 Butyl glycol 3.00 Isopar L, available from Exxon Mobil 2.20 2.40 Isotridecyl alcohol 1.80 1.90 White paste 1 22.00 White paste 2 21.50 Black paste 22.00 21.50 Barium sulfate paste 17.00

[0327] Preparation of White Paste 1

[0328] The white paste is prepared from 50 parts by weight of titanium rutile R-960-38, 11 parts by weight of a polyester prepared as per example D, column 16, lines 37-59 of DE 40 09 858 A1, 16 parts by weight of a binder dispersion prepared as per international patent application WO 92/15405, page 15, lines 23-28, 16.5 parts by weight of deionized water, 3 parts by weight of butyl glycol, 1.5 parts by weight of 10% strength dimethylethanolamine in water, and 1.5 parts by weight of Pluriol P900, available from BASF SE.

[0329] Preparation of White Paste 2

[0330] The white paste is prepared from 50 parts by weight of titanium rutile 2310, 6 parts by weight of a polyester prepared as for example D, column 16, lines 37-59 of DE 40 09 858 A1, 24.7 parts by weight of a binder dispersion prepared as per patent application EP 022 8003 B2, page 8, lines 6 to 18, 10.5 parts by weight of deionized water, 4 parts by weight of 2,4,7,9-tetramethyl-5-decynediol, 52% in BG (available from BASF SE), 4.1 parts by weight of butyl glycol, 0.4 part by weight of 10% strength dimethylethanolamine in water, and 0.3 part by weight of Acrysol RM-8 (available from The Dow Chemical Company).

[0331] Preparation of the Black Paste

[0332] The black paste is prepared from 58.9 parts by weight of a polyurethane dispersion prepared as per WO 92/15405, page 13, line 13 to page 15, line 13, 10.1 parts by weight of carbon black (Color Black FW2 from Orion Engineered Carbons), 5 parts by weight of a polyester prepared as per example D, column 16, lines 37-59 of DE 40 09 858 A1, 7.8 parts by weight of a 10% strength aqueous dimethylethanolamine solution, 2.2 parts by weight of a commercial polyether (Pluriol P900, available from BASF SE), 7.6 parts by weight of butyl diglycol, and 8.4 parts by weight of deionized water.

[0333] Preparation of the Barium Sulfate Paste

[0334] The barium sulfate paste is prepared from 39 parts by weight of a polyurethane dispersion prepared as per EP 0228003 B2, page 8, lines 6 to 18, 54 parts by weight of barium sulfate (Blanc fixe micro from Sachtleben Chemie GmbH), 3.7 parts by weight of butyl glycol, and 0.3 part by weight of Agitan 282 (available from Mnzing Chemie GmbH), and 3 parts by weight of deionized water.

[0335] 1.2 Preparation of a Noninventive Waterborne Basecoat Material WBM B1, of a Noninventive Waterborne Basecoat Material WBM B2, and of an Inventive Waterborne Basecoat Material WBM B3

[0336] The components listed under Aqueous phase in table 1.2 are combined with stirring in the order stated to form an aqueous mixture. In the next step, an organic mixture is prepared from the components listed under organic phase. The organic mixture is added to the aqueous mixture. This 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 805 mPa.Math.s under a shearing load of 1000 s.sup.1, as measured using a rotary viscometer (Rheolab QC instrument with C-LTD80/QC heating system from Anton Paar) at 23 C.

TABLE-US-00010 TABLE 1.2 Preparation of waterborne basecoat materials WBM B1 and WBM B2 (not inventive) and WBM B3 (inventive) WBM B1 WBM B2 WBM B3 Aqueous phase: 3% strength Na Mg phyllosilicate 15.70 15.70 15.70 solution Deionized water 17.20 13.65 13.65 Isopropanol 1.50 1.50 1.50 2-Ethylhexanol 1.70 1.70 1.70 Aqueous binder dispersion; prepared as 22.25 per WO 92/15405, page 13, line 13 to page 15, line 13 Daotan VTW 6464, available from 1.50 Allnex Multistage acrylate, prepared as per 29.75 Korea Polym. J., Vol. 7, No. 4, pp. 213-222 (aqueous dispersion BM8) Aqueous dispersion (wD) BM2 27.30 3 wt % strength aqueous Rheovis AS 1130 4.40 4.40 4.40 solution, Rheovis AS 1130 available from BASF SE Melamine formaldehyde resin (Cymel 3.10 3.10 3.10 1133 from Allnex) 2,4,7,9-Tetramethyl-5-decynediol, 52% 1.15 1.15 1.15 in BG (available from BASF SE) 10% strength dimethylethanolamine in 0.50 0.50 0.50 water BYK-347 from Altana/BYK-Chemie GmbH 0.50 0.50 0.50 Pluriol P900, available from BASF SE 0.35 0.35 0.35 Triisobutyl phosphate 1.00 1.00 1.00 Polyurethane-modified polyacrylate; 2.50 2.50 2.50 prepared as per page 7, line 55 to page 8, line 23 of DE 4437535 A1 Butyl glycol 2.20 2.20 2.20 50 wt % strength solution of Rheovis 0.20 0.20 0.20 PU1250 in butyl glycol (Rheovis PU1250 available from BASF SE) Tinuvin 384-2, available from BASF SE 0.55 0.55 0.55 Tinuvin 123, available from BASF SE 0.35 0.35 0.35 Red paste 9.00 9.00 9.00 Black paste 0.60 0.60 0.60 Mica paste 1 4.80 4.80 4.80 Mica paste 2 1.60 1.60 1.60 Organic phase: Paliocrom Orange L2804, available from 0.60 0.60 0.60 BASF SE Butyl glycol 3.00 3.00 3.00 Polyester; prepared as per example D, 3.45 3.45 3.45 column 16, lines 37-59 of DE 40 09 858 A1 10% strength dimethylethanolamine in 0.30 0.30 0.30 water

[0337] Preparation of Red Paste

[0338] The red paste is prepared from 21 parts by weight of Paliogen Red L 3885, 45 parts by weight of an aqueous binder dispersion prepared as per WO 91/15528, page 23, line 26 to page 25, line 24, 2.5 percent by weight of 1-propoxy-2-propanol, 0.7 part by weight of 10% strength dimethylethanolamine in water, and 30.8 parts by weight of deionized water.

[0339] Preparation of Black Paste

[0340] The black paste is prepared from 57 parts by weight of a polyurethane dispersion prepared as per WO 92/15405, page 13, line 13 to page 15, line 13, 10 parts by weight of carbon black ( Monarch 1400 carbon black from Cabot Corporation), 5 parts by weight of a polyester prepared as per example D, column 16, lines 37-59 of DE 40 09 858 A1, 6.5 parts by weight of a 10% strength aqueous dimethylethanolamine solution, 2.5 parts by weight of a commercial polyether (Pluriol P900, available from BASF SE), 7 parts by weight of butyl diglycol, and 12 parts by weight of deionized water.

[0341] Preparation of Mica Paste 1

[0342] The mica paste 1 is obtained by using a stirring element to mix 75 parts by weight of a mixing varnish prepared according to EP 1534792 B1, column 11, lines 1-17 with 25 parts by weight of the commercial Mica Mearlin Ext. Fine Russet 459V from BASF SE.

[0343] Preparation of Mica Paste 2

[0344] The mica paste 2 is obtained by using a stirring element to mix 75 parts by weight of a mixing varnish prepared according to EP 1534792 B1, column 11, lines 1-17 with 25 parts by weight of the commercial Mica Mearlin Ext. Super Russet 459V from BASF SE.

[0345] 1.3 Preparation of a Noninventive Waterborne Basecoat Material WBM B4 and of an Inventive Waterborne Basecoat Material WBM B5

[0346] The components listed under Aqueous phase in table 1.3 are combined with stirring in the order stated to form an aqueous mixture. This 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 955 mPa.Math.s under a shearing load of 1000 s.sup.1, as measured using a rotary viscometer (Rheolab QC instrument with C-LTD80/QC heating system from Anton Paar) at 23 C.

TABLE-US-00011 TABLE 1.3 Preparation of waterborne basecoat materials WBM B4 (not inventive) and WBM B5 (inventive) Aqueous phase: WBM B4 WBM B5 3% strength Na Mg phyllosilicate solution 4.20 4.20 Deionized water 6.36 6.36 Butyl glycol 4.00 4.00 2-Ethylhexanol 3.55 3.55 Aqueous binder dispersion; prepared as per 15.50 WO 92/15405, page 13, line 13 to page 15, line 13 Daotan VTW 6462, available from Allnex 7.00 Aqueous dispersion (wD) BM2 29.65 Polyester; prepared as per example D, 1.00 1.00 column 16, lines 37-59 of DE 40 09 858 A1 Deionized water 4.20 4.20 30 wt % strength aqueous Rheovis AS 1130 0.42 0.42 solution, available from BASF SE Melamine formaldehyde resin (Cymel 203 from 7.70 7.80 Allnex) 2,4,7,9-Tetramethyl-5-decynediol, 52% in BG 1.80 1.80 (available from BASF SE) 10% strength dimethylethanolamine in water 0.68 0.68 Pluriol P900, available from BASF SE 0.10 0.10 Triisobutyl phosphate 2.50 2.50 Polyurethane-modified polyacrylate; prepared 3.60 as per page 7, line 55 to page 8, line 23 of DE 4437535 A1 White paste 35.00 35.00 Yellow paste 0.12 0.12 Black paste 0.11 0.11 Steatite paste 2.40 2.40

[0347] Preparation of White Paste

[0348] The white paste is prepared from 50 parts by weight of titanium rutile R-960-38, 11 parts by weight of a polyester prepared as per example D, column 16, lines 37-59 of DE 40 09 858 A1, 16 parts by weight of a binder dispersion prepared as per international patent application WO 92/15405, page 15, lines 23-28, 16.5 parts by weight of deionized water, 3 parts by weight of butyl glycol, 1.5 parts by weight of 10% strength dimethylethanolamine in water, and 1.5 parts by weight of Pluriol P900, available from BASF SE.

[0349] Preparation of Yellow Paste

[0350] The yellow paste is prepared from 47 parts by weight of Sicotan Yellow L 1912, 45 parts by weight of an aqueous binder dispersion prepared as per WO 91/15528, page 23, line 26 to page 25, line 24, 2.7 percent by weight of 1-propoxy-2-propanol, 2.8 parts by weight of deionized water, 1.5 parts by weight of Disperbyk-184 (available from BYK-Chemie GmbH), and 1 part by weight of Aerosil R 972 (available from Evonik Industries).

[0351] Preparation of Black Paste

[0352] The black paste is prepared from 40 parts by weight of Bayferrox 318 M (available from Lanxess), 39 parts by weight of an aqueous binder dispersion prepared as per WO 91/15528, page 23, line 26 to page 25, line 24, 2.0 percent by weight of 1-propoxy-2-propanol, 11.1 parts by weight of deionized water, 0.5 part by weight of Agitan 282 (available from Mnzing Chemie GmbH), 4.4 parts by weight of Pluriol P900 (available from BASF SE), and 3 parts by weight of 10% strength dimethylethanolamine in water.

[0353] Preparation of Steatite Paste

[0354] The steatite paste is prepared from 49.7 parts by weight of an aqueous binder dispersion prepared as per WO 91/15528, page 23, line 26 to page 25, line 24, 28.9 parts by weight of steatite (Microtalc IT extra from Mondo Minerals B.V.), 0.4 part by weight of Agitan 282 (available from Mnzing Chemie GmbH), 1.45 parts by weight of Disperbyk-184 (available from BYK-Chemie GmbH), 3.1 parts by weight of a commercial polyether (Pluriol P900, available from BASF SE), and 16.45 parts by weight of deionized water.

[0355] 1.4 Preparation of the Noninventive Waterborne Basecoat Materials WBM B6 and WBM B8 and of the Inventive Waterborne Basecoat Materials WBM B7 and WBM B9

[0356] The components listed under Aqueous phase in table 1.4 are combined with stirring in the order stated to form an aqueous mixture. This 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 12010 mPa.Math.s (WBM B6 and WBM B8) or 11010 mPa.Math.s (WBM B7 and WBM B9) under a shearing load of 1000 s.sup.1, as measured using a rotary viscometer (Rheolab QC instrument with C-LTD80/QC heating system from Anton Paar) at 23 C.

TABLE-US-00012 TABLE 1.4 Preparation of waterborne basecoat materials WBM B6 and WBM B8 (not inventive) and WBM B7 and WBM B9 (inventive) Aqueous phase: WBM B6 WBM B7 WBM B8 WBM B9 3% strength Na Mg phyllosilicate 13.71 13.71 13.54 13.54 solution Deionized water 14.37 10.15 12.93 8.03 2-Ethylhexanol 1.40 1.40 1.54 1.54 Aqueous binder dispersion; 33.80 39.14 prepared as per WO 92/15405, page 13, line 13 to page 15, line 13 Aqueous dispersion (wD) BM2 38.02 44.04 Polyester; prepared as per 4.45 4.45 4.40 4.40 example D, column 16, lines 37- 59 of DE 40 09 858 A1 Melamine formaldehyde resin 4.10 4.10 (Cymel 3020 from Allnex) Melamine formaldehyde resin 3.96 3.96 (Cymel 303 from Allnex) 10% strength dimethylethanol- 1.22 1.22 1.21 1.21 amine in water 2,4,7,9-Tetramethyl-5- 1.14 1.14 0.63 0.63 decynediol, 52% in BG (available from BASF SE) Pluriol P900, available from 1.14 1.14 1.26 1.26 BASF SE Triisobutyl phosphate 0.50 0.50 0.55 0.55 NACURE 2500, available from King 0.66 0.66 0.72 0.72 Industries, Inc Polyurethane-modified 3.70 3.70 polyacrylate; prepared as per page 7, line 55 to page 8, line 23 of DE 4437535 A1 Butyl glycol 5.24 5.24 5.18 5.18 50 wt % strength solution of 0.57 0.57 0.63 0.63 Rheovis PU1250 in butyl glycol (Rheovis PU1250 available from BASF SE) Black paste 14.00 14.00 14.31 14.31

[0357] Preparation of Black Paste

[0358] The black paste is prepared from 57 parts by weight of a polyurethane dispersion prepared as per WO 92/15405, page 13, line 13 to page 15, line 13, 10 parts by weight of carbon black (Monarch 1400 carbon black from Cabot Corporation), 5 parts by weight of a polyester prepared as per example D, column 16, lines 37-59 of DE 40 09 858 A1, 6.5 parts by weight of a 10% strength aqueous dimethylethanolamine solution, 2.5 parts by weight of a commercial polyether (Pluriol P900, available from BASF SE), 7 parts by weight of butyl diglycol, and 12 parts by weight of deionized water.

[0359] 1.5 Preparation of the Noninventive Waterborne Basecoat Materials WBM B10 and WBM B12 and of the Inventive Waterborne Basecoat Materials WBM B11 and WBM B13

[0360] The components listed under Aqueous phase in table 1.5 are combined with stirring in the order stated to form an aqueous mixture. This 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 1155 mPa.Math.s (WBM B10 and WBM B12) or 905 mPa.Math.s (WBM B11 and WBM B13) under a shearing load of 1000 s.sup.1, as measured using a rotary viscometer (Rheolab QC instrument with C-LTD80/QC heating system from Anton Paar) at 23 C.

TABLE-US-00013 TABLE 1.5 Preparation of waterborne basecoat materials WBM B10 and WBM B12 (not inventive) and WBM B11 and WBM B13 (inventive) Aqueous phase: WBM B10 WBM B11 WBM B12 WBM B13 3% strength Na Mg phyllosilicate 13.10 13.10 11.790 11.790 solution Deionized water 9.49 10.53 12.96 8.39 n-Propanol 0.87 0.87 0.79 0.79 n-Butoxypropanol 1.38 1.38 1.24 1.24 2-Ethylhexanol 2.77 2.77 2.49 2.49 Aqueous binder dispersion; 36.28 36.44 prepared as per WO 92/15405, page 13, line 13 to page 15, line 13 Aqueous dispersion (wD) BM2 35.24 41.00 Polyester; prepared as per 2.95 2.95 2.66 2.66 example D, column 16, lines 37- 59 of DE 40 09 858 A1 Melamine formaldehyde resin 4.10 4.10 3.70 3.70 (Resimene HM 2608 from Ineos) 10% strength dimethylethanol- 0.30 0.30 0.27 0.27 amine in water 2,4,7,9-Tetramethyl-5- 1.38 1.38 1.25 1.25 decynediol, 52% in BG (available from BASF SE) BYK-346, available from 0.46 0.46 0.41 0.41 Altana/BYK-Chemie GmbH Polyurethane-modified 2.77 2.77 polyacrylate; prepared as per page 7, line 55 to page 8, line 23 of DE 4437535 A1 Isopropanol 1.64 1.64 1.48 1.48 Butyl glycol 1.00 1.00 0.90 0.90 Isopar L, available from Exxon 0.87 0.87 0.79 0.79 Mobil NACURE 2500, available from 0.42 0.42 0.38 0.38 King Industries, Inc Black paste 12.99 12.99 12.60 12.60 Blue paste 0.78 0.78 Barium sulfate paste 3.21 3.21 2.88 2.88 Steatite paste 3.25 3.25 2.93 2.93

[0361] Preparation of Black Paste

[0362] The black paste is prepared from 57 parts by weight of a polyurethane dispersion prepared as per WO 92/15405, page 13, line 13 to page 15, line 13, 10 parts by weight of carbon black (Monarch 1400 carbon black from Cabot Corporation), 5 parts by weight of a polyester prepared as per example D, column 16, lines 37-59 of DE 40 09 858 A1, 6.5 parts by weight of a 10% strength aqueous dimethylethanolamine solution, 2.5 parts by weight of a commercial polyether (Pluriol P900, available from BASF SE), 7 parts by weight of butyl diglycol, and 12 parts by weight of deionized water.

[0363] Preparation of Blue Paste

[0364] The blue paste was prepared from 69.8 parts by weight of a polyurethane dispersion prepared as per WO 92/15405, page 13, line 13 to page 15, line 13, 12.5 parts by weight of Paliogen Blue L 6482 (available from BASF SE), 1.5 parts by weight of a 10% strength aqueous dimethylethanolamine solution, 1.2 parts by weight of a commercial polyether (Pluriol P900, available from BASF SE), and 15 parts by weight of deionized water.

[0365] Preparation of Barium Sulfate Paste

[0366] The barium sulfate paste is prepared from 39 parts by weight of a polyurethane dispersion prepared as per EP 0228003 B2, page 8, lines 6 to 18, 54 parts by weight of barium sulfate (Blanc fixe micro from Sachtleben Chemie GmbH), 3.7 parts by weight of butyl glycol, and 0.3 part by weight of Agitan 282 (available from Mnzing Chemie GmbH), and 3 parts by weight of deionized water.

[0367] Preparation of Steatite Paste

[0368] The steatite paste is prepared from 49.7 parts by weight of an aqueous binder dispersion prepared as per WO 91/15528, page 23, line 26 to page 25, line 24, 28.9 parts by weight of steatite (Microtalc IT extra from Mondo Minerals B.V.), 0.4 part by weight of Agitan 282 (available from Mnzing Chemie GmbH), 1.45 parts by weight of Disperbyk-184 (available from BYK-Chemie GmbH), 3.1 parts by weight of a commercial polyether (Pluriol P900, available from BASF SE), and 16.45 parts by weight of deionized water.

[0369] Comparison of Waterborne Basecoat Materials WBM A2 and WBM A3

[0370] The amount of deionized water needed to set the spray viscosity for waterborne basecoat materials WBM A2 and WBM A3, and the resulting solids content of the respective formulation, are summarized in table 1.6.

TABLE-US-00014 TABLE 1.6 Amount of water to set the spray viscosity and resultant solids content of basecoat materials WBM A2 and WBM A3 WBM A2 WBM A3 Addition of water [parts by weight] to 85.00 2.75 set the spray viscosity Spray viscosity [mPa .Math. s], measured at 90 90 1291/s Solids content [%] 19.1 32.6

[0371] The results demonstrate that the use of the multistage acrylate, used for comparison, in basecoat materials, in view of the high amount of deionized water needed to set the spray viscosity, results in a solids content which is well below that of inventive waterborne basecoat material WBM A3.

[0372] The running limit and popping limit were assessed for waterborne basecoat materials WBM A2 and WBM A3 in accordance with the methods described above. Here it was found that the popping limit and running limit were significantly higher when using a basecoat material for inventive use (see table 1.7).

TABLE-US-00015 TABLE 1.7 Popping and running limits of basecoat materials WBM A2 and WBM A3 WBM A2 WBM A3 Running limit [m] 6 m >50 m Popping limit 9 m >40 m

[0373] Comparison Between Waterborne Basecoat Materials WBM B1 and WBM B2 and Waterborne Basecoat Material WBM B3

[0374] The amount of deionized water needed to set the spray viscosity for waterborne basecoat materials WBM B1, WBM B2 and WBM B3, and the resulting solids content of the respective formulation, are summarized in table 1.8.

TABLE-US-00016 TABLE 1.8 Amount of water to set the spray viscosity and resultant solids content of basecoat materials WBM B1, WBM B2 and WBM B3 WBM B1 WBM B2 WBM B3 Addition of water [parts by weight] 0 70 0 to set the spray viscosity Spray viscosity [mPa .Math. s], measured 76 83 77 at 1000 1/s Solids content [%] 21.9 13.1 21.2

[0375] The pinholing sensitivity was assessed according to the method described above. The results are summarized in table 1.9.

TABLE-US-00017 TABLE 1.9 Results of investigations into pinholing Number of pinholes (standardized for 200 cm.sup.2): Paint system 1. Waterborne basecoat WBM A3 WBM A3 as wedge Paint system 2. Waterborne basecoat WBM B1 WBM B3 constant Film thickness range basecoat total film (waterborne basecoat 1 + waterborne basecoat 2) 0-20 m 5 0 20 m-End of wedge 34 1 Total 39 1 Number of pinholes (standardized for 200 cm.sup.2): Paint system 1. Waterborne basecoat WBM A3 WBM A3 constant Paint system 2. Waterborne basecoat WBM B1 WBM B3 as wedge Film thickness range basecoat total film (waterborne basecoat 1 + waterborne basecoat 2) 0-20 m 9 4 20 m-End of wedge 84 6 Total 93 10

[0376] The results from table 1.8 demonstrate that when using the multistage acrylate (WBM B2), used for comparison, in basecoat materials, on account of the large amount of deionized water needed to set the spray viscosity, a solids content results which is no longer acceptable for application in modern multicoat paint systems of the kind used in the automobile industry. An attempt was made to reduce the amount of water required to set spray viscosity (i.e., around 80 mPas at 1000 l/s) by significantly reducing the thickener proportion (of the 3% strength NaMg phyllosilicate solution) and thereby to increase the solids content. As a consequence of this, however, it emerged that the paint, following application and under the then low-shear conditions, had much too low a viscosity and hence caused massive runs.

[0377] The results from tables 1.8 and 1.9 show that while the comparative basecoat material WBM B1 does have an acceptable spray viscosity even without addition of water, it exhibits significant deficiencies at high film thicknesses in terms of the pinholing behavior. Especially when using waterborne basecoat materials for inventive use to produce all of the basecoat films present, there is a qualitatively enormously high-grade pinholing robustness even at high film thicknesses.

[0378] Comparison Between Waterborne Basecoat Material WBM B4 and WBM B5

[0379] The investigations on waterborne basecoat materials WBM B4 and WBM B5 took place in accordance with the above-described method of film thickness-dependent leveling, variant B.

TABLE-US-00018 TABLE 1.10 Results of investigations into the film thickness-dependent leveling Paint system 1. WBM A3 WBM A3 Waterborne basecoat constant Paint system 2. WBM B4 WBM B5 Waterborne basecoat as wedge Film thickness range Appearance 2. waterborne base- index coat SW 15-20 m 30.7 28.9 20-25 m 33.9 31.1 LW 15-20 m 11.0 11.6 20-25 m 10.9 11.7 DOI 15-20 m 71.4 75.3 20-25 m 70.0 73.1

[0380] The results show that especially when using waterborne basecoat materials for inventive use for producing all of the basecoat films present, the multicoat paint system is qualitatively extremely high-grade in particular with regard to short wave and DOI.

[0381] Comparison Between Waterborne Basecoat Materials WBM B6 and WBM B8 and Waterborne Basecoat Materials WBM B7 and WBM B9

[0382] The investigation on waterborne basecoat materials WBM B6 and WBM B8 and also WBM B7 and WBM B9 were carried out according to the above-described methods of pinholes, variant A and B, runs, and film thickness-dependent leveling, variant A and B.

TABLE-US-00019 TABLE 1.11 Results of investigations into pinholing Number of pinholes (standardized for 200 cm.sup.2): Paint system 1. WBM A3 WBM A3 WBM A3 WBM A3 Waterborne basecoat as wedge Paint system 2. WBM B6 WBM B7 WBM B8 WBM B9 Waterborne basecoat constant Film thickness range basecoat total film (waterborne basecoat 1 + waterborne basecoat 2) 0-20 m 5 8 0 3 20 m-End of wedge 65 7 76 3 Total 70 15 76 6 Number of pinholes (standardized for 200 cm.sup.2): Paint system 1. WBM A3 WBM A3 WBM A3 WBM A3 Waterborne basecoat constant Paint system 2. WBM B6 WBM B7 WBM B8 WBM B9 Waterborne basecoat as wedge Film thickness range basecoat total film (waterborne basecoat 1 + waterborne basecoat 2) 0-20 m 0 0 0 1 20 m-End of wedge >2500 2 440 4 Total >2500 2 440 5

[0383] All of the multicoat paint systems produced exhibited good pinholing robustness in the low range of the total film thickness of all basecoat films present. The particularly preferred systems, in which each basecoat material used comprises an inventive dispersion, have a correspondingly good pinholing robustness even at very high total film thicknesses.

TABLE-US-00020 TABLE 1.12 Results of the investigations into running stability WBM B6 WBM B7 WBM B8 WBM B9 Running limit (>0 mm): 11 m 15 m 17 m >30 m Running limit (>10 mm): 23 m 32 m 31 m >50 m

[0384] The waterborne basecoat materials for inventive use (WBM B7 and WBM B9) differ in comparison to the respective noninventive references (WBM B6 as reference for WBM B7, and WBM B8 as reference for WBM B9) in having a lower running tendency.

TABLE-US-00021 TABLE 1.13 Results of investigations into the film thickness-dependent leveling Paint system 1. Waterborne WBM A3 WBM A3 basecoat constant Paint system 2. Waterborne WBM B6 WBM B7 basecoat as wedge Appearance Film thickness range 2. base- index coat SW 10 m-15 m 17.0 10.6 15 m-20 m 17.4 13.0 20 m-25 m 17.7 14.1 25 m-30 m 23.8 17.5 30 m-35 m 28.2 19.0 LW 10 m-15 m 8.5 10.3 15 m-20 m 7.2 11.2 20 m-25 m 6.1 11.9 25 m-30 m 16.4 11.4 30 m-35 m 34.9 11.2 DOI 10 m-15 m 90.5 96.0 15 m-20 m 90.9 95.4 20 m-25 m 90.7 94.8 25 m-30 m 84.1 93.2 30 m-35 m 71.1 92.5

[0385] Relative to the WBM A3/WBM B6 system, advantages are found for the WBM A3/WBM B7 system in terms of short wave (SW) and long wave (LW) in the higher film thickness range. Here it is found for the LW measured for the wedge of the waterborne basecoat material WBM B7 that it is virtually independent of the film thickness, in comparison to waterborne basecoat material WBM B6, whereas the LW in the case of WBM B6 increased drastically as the film thickness goes up.

[0386] The effect of using the WBM A3/WBM B7 system relative to the WBM A3/WBM B6 system, moreover, is an improvement in the distinctness of image (DOI); the corresponding particularly preferred system shows a significantly lower decrease in the DOI with increasing film thickness of the 2nd waterborne basecoat.

[0387] Comparison Between Waterborne Basecoat Materials WBM B10 and WBM B12 and Waterborne Basecoat Materials WBM B11 and WBM B13

[0388] The investigations on waterborne basecoat materials WBM B10 and WBM B12 and also WBM B11 and WBM B13 were carried out according to the above-described methods of pinholes, variant A and B, and film thickness-dependent leveling, variant A and B.

TABLE-US-00022 TABLE 1.14 Results of investigations into pinholing Number of pinholes (standardized for 200 cm.sup.2): Paint system 1. Waterborne basecoat as wedge WBM A1 WBM A1 Paint system 2. Waterborne basecoat constant WBM WBM B10 B11 Film thickness range basecoat total film (waterborne basecoat 1 + waterborne basecoat 2) 0-20 m 6 10 20 m-End of wedge 160 24 Total 166 34 Number of pinholes (standardized for 200 cm.sup.2): Paint system 1. Waterborne basecoat constant WBM A1 WBM A1 Paint system 2. Waterborne basecoat as wedge WBM WBM B10 B11 Film thickness range basecoat total film (waterborne basecoat 1 + waterborne basecoat 2) 0-20 m >100 63 20 m-End of wedge >500 21 Total >600 84

[0389] The results show that the inventive system has distinct advantages in terms of pinholing stability, especially in the range of high film thicknesses.

TABLE-US-00023 TABLE 1.15 Further results of investigations into pinholing Number of pinholes (standardized for 200 cm.sup.2): Paint system 1. Waterborne WBM A3 WBM A3 WBM A3 WBM A3 basecoat as wedge Paint system 2. Waterborne WBM B10 WBM B11 WBM B12 WBM B13 basecoat constant Film thickness range basecoat total film (waterborne basecoat 1 + waterborne basecoat 2) 0-20 m 5 7 0 0 20 m-End of wedge 296 2 464 0 Total 301 9 464 0 Number of pinholes (standardized for 200 cm.sup.2): Paint system 1. Waterborne WBM A3 WBM A3 WBM A3 WBM A3 basecoat constant Paint system 2. Waterborne WBM B10 WBM B11 WBM B12 WBM B13 basecoat as wedge Film thickness range basecoat total film (waterborne basecoat 1 + waterborne basecoat 2) 0-20 m >500 7 0 0 20 m-End of wedge >1000 0 >1600 0 Total >1500 7 >1600 0

[0390] The majority of multicoat paint systems produced exhibit good pinholing robustness in the low range of the total film thickness for all the basecoat films present. The particularly preferred systems, in which each basecoat material used comprises an inventive dispersion, have a correspondingly good pinholing robustness even at very high total film thicknesses.

TABLE-US-00024 TABLE 1.16 Results of investigations into the film thickness-dependent leveling Paint system 1. WBM A3 WBM A3 WBM A3 WBM A3 Waterborne basecoat as wedge Paint system 2. WBM B10 WBM B11 WBM B12 WBM B13 Waterborne basecoat constant Appearance Film thickness range index 2. basecoat WBM B10 WBM B11 WBM B12 WBM B13 SW 5 m-10 m 19.6 18.0 19.3 17.2 10 m-15 m 24.1 15.9 20.8 17.4 15 m-20 m 29.3 16.2 23.2 18.2 20 m-25 m 34.1 18.0 25.9 19.7 25 m-30 m 35.1 20.9 27.8 20.9 LW 5 m-10 m 4.2 4.9 7.6 12.6 10 m-15 m 4.6 4.5 8.3 11.1 15 m-20 m 5.6 4.7 9.3 11.2 20 m-25 m 10.4 5.1 10.3 10.2 25 m-30 m 12.3 5.3 14.1 9.2 DOI 5 m-10 m 90.9 93.0 92.3 92.8 10 m-15 m 84.6 93.0 87.9 92.9 15 m-20 m 78.6 91.6 86.8 92.5 20 m-25 m 72.2 89.6 84.3 91.7 25 m-30 m 70.5 87.2 81.5 91.3

[0391] The results underscore again that the particularly preferred systems, in which all of the basecoat materials used comprise an aqueous dispersion (wD), have advantages. While all of the inventive multicoat paint systems exhibit good values in the lower film thickness range, the advantages of the particularly preferred systems, particularly at higher film thicknesses, are evident in short wave (SW) and in long wave (LW) or in the distinctness of image (DOI).

[0392] Comparison Between Waterborne Basecoat Material WBM A4 and Waterborne Basecoat Material WBM A5

[0393] The investigations on waterborne basecoat materials WBM A4 and WBM A5, in each case in combination with the waterborne basecoat material WBM B4, take place according to the above-described method of film thickness-independent leveling.

TABLE-US-00025 TABLE 1.17 Results of the investigations into film thickness-independent leveling Paint system 1. Waterborne basecoat WBM A4 WBM A5 Paint system 2. Waterborne basecoat WBM B4 WBM B4 SW 28.0 22.0 LW 5.0 4.7 DOI 88.6 92.8

[0394] The results underscore again that the inventive systems, in which at least one basecoat material used comprises an aqueous dispersion (wD), have advantages. All of the inventive multicoat paint systems have clear advantages in short wave (SW) and in long wave (LW) and also in the distinctness of image (DOI).

[0395] Comparison Between Waterborne Basecoat Material WBM B10 and Waterborne Basecoat Material WBM B11

[0396] The investigations on waterborne basecoat materials WBM B10 and WBM B11 take place in accordance with the above-described methods of Adhesion properties after condensation, runs, and film thickness-dependent leveling (variant C).

TABLE-US-00026 TABLE 1.18 Adhesion after condensation storage Waterborne basecoat Adhesion after condensation storage WBM B10 WBM B11 Cross-cut 0.5 0.5 Steam jet 1 1 Stonechip 2 1.5

[0397] The waterborne basecoat material WBM B11 is comparable in terms of cross-cut and steam jet with the reference WBM B10, but exhibits advantages in terms of stonechipping.

TABLE-US-00027 TABLE 1.19 Running behavior Waterborne basecoat Runs WBM B10 WBM B11 Runs start 10 m >30 m Runs 10 mm 28 m >30 m

[0398] The results demonstrate that the inventive systems, in which the basecoat material used comprises an aqueous dispersion (wD) (WBM B11), exhibit advantages in terms of the running behavior. When using WBM B11, even at the maximum film thickness, there are still no discernible tendencies toward development of runs.

TABLE-US-00028 TABLE 1.20 Results of the investigations into film thickness-dependent leveling Film thickness range Waterborne basecoat Appearance index basecoat WBM B10 WBM B11 SW 10 m-15 m 13.2 12.8 15 m-20 m 15.0 12.9 20 m-25 m 15.7 12.1 25 m-30 m 15.8 12.0 LW 10 m-15 m 3.6 2.7 15 m-20 m 3.0 2.4 20 m-25 m 2.7 2.6 25 m-30 m 2.9 2.7 DOI 10 m-15 m 93.3 94.4 15 m-20 m 93.0 94.4 20 m-25 m 92.7 94.7 25 m-30 m 92.2 94.8

[0399] The results underscore again that the inventive systems, in which the basecoat material used comprises an aqueous dispersion (wD), have advantages. The inventive multicoat paint system has distinct advantages in short wave (SW) and in long wave (LW) and also in the distinctness of image (DOI).

BRIEF DESCRIPTION OF THE FIGURES

[0400] FIG. 1: Schematic construction of a multicoat paint system of the invention (M), disposed on a metallic substrate (S), and comprising a cured electrocoat (E.1) and also a basecoat (B.2.1) and a clearcoat (K) which have been jointly cured.

[0401] FIG. 2: Schematic construction of a multicoat paint system of the invention (M), disposed on a metallic substrate (S), and comprising a cured electrocoat (E.1), two basecoats (B.2.2.x), namely a first basecoat (B.2.2.a) and a topmost basecoat (B.2.2.z) arranged over it, and also a clearcoat (K), which have been jointly cured.

[0402] FIG. 3: Schematic construction of a multicoat paint system of the invention (M), disposed on a metallic substrate (S), and comprising a cured electrocoat (E.1), three basecoats (B.2.2.x), namely a first basecoat (B.2.2.a), a basecoat (B.2.2.b), and a topmost basecoat (B.2.2.z), arranged over it, and also a clearcoat (K), which have been jointly cured.