CARBOXY-FUNCTIONAL POLYETHER-BASED REACTION PRODUCTS AND AQUEOUS BASE PAINTS CONTAINING THE REACTION PRODUCTS

Abstract

Described herein is a pigmented aqueous basecoat material including a polyether-based reaction product which is preparable by reaction of (a) at least one cyclic tetracarboxylic dianhydride having an aliphatic, aromatic, or araliphatic radical X bridging the two anhydride groups with (b) at least one polyether of the general structural formula (II)

##STR00001## in which R is a C.sub.3 to C.sub.6 alkylene radical and n is selected accordingly such that the polyether (b) possesses a number-average molecular weight of 500 to 5000 g/mol, the components (a) and (b) being used in the reaction in a molar ratio of 0.7/2.3 to 1.6/1.7 and the resulting reaction product possessing an acid number of 5 to 80 mg KOH/g. Also described herein is a reaction product of specific dianhydrides and a polyether, and the use of the pigmented aqueous basecoat material or the reaction product.

Claims

1. A pigmented aqueous basecoat material comprising a polyether-based reaction product which is preparable by reaction of (a) at least one cyclic tetracarboxylic dianhydride having an aliphatic, aromatic, or araliphatic radical X bridging the two anhydride groups with (b) at least one polyether of the general structural formula (II) ##STR00007## in which R is a C.sub.3 to C.sub.6 alkylene radical and n is selected accordingly such that the polyether (b) possesses a number-average molecular weight of 500 to 5000 g/mol, the components (a) and (b) being used in the reaction in a molar ratio of 0.7/2.3 to 1.6/1.7 and the resulting reaction product possessing an acid number of 5 to 80 mg KOH/g.

2. The pigmented aqueous basecoat material as claimed in claim 1, wherein the polyether (b) possesses a number-average molecular weight of 650 to 4000 g/mol.

3. The pigmented aqueous basecoat material as claimed in claim 1, wherein the group R in the general structural formula (II) comprises tetramethylene radicals.

4. The pigmented aqueous basecoat material as claimed in claim 1, wherein the components (a) and (b) are used in a molar ratio of 0.45/1 to 0.55/1.

5. The pigmented aqueous basecoat material as claimed in claim 1, wherein the polyether-based reaction product possesses a number-average molecular weight of 1500 to 15000 g/mol.

6. The pigmented aqueous basecoat material as claimed in claim 1, which has an acid number of 8 to 60 mg KOH/g.

7. The pigmented aqueous basecoat material as claimed in claim 1, wherein a sum total of weight-percentage fractions, based on a total weight of the pigmented aqueous basecoat material, of all polyether-based reaction products is 0.1 to 20 wt %.

8. The pigmented aqueous basecoat material as claimed in claim 1, further comprising a melamine resin and a polyurethane resin that is grafted by means of olefinically unsaturated monomers and that further comprises hydroxyl groups.

9. The pigmented aqueous basecoat material as claimed in claim 1, wherein the tetracarboxylic dianhydride (a) is pyromellitic dianhydride, cyclobutanetetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, bicyclooctenetetracarboxylic dianhydride and/or diphenylsulfonyltetracarboxylic dianhydride.

10. The pigmented aqueous basecoat material as claimed in claim 1, wherein the polyether-based reaction product is further preparable by reaction of (a1) at least one tetracarboxylic dianhydride of the general structural formula (I) ##STR00008## in which X.sub.1 is a bond or an aliphatic, aromatic or araliphatic radical with (b) at least one polyether of the general structural formula (II) ##STR00009## in which R is a C.sub.3 to C.sub.6 alkylene radical and n is selected accordingly such that the polyether (b) possesses a number-average molecular weight of 500 to 5000 g/mol, the components (a) and (b) being used in the reaction in a molar ratio of 0.7/2.3 to 1.6/1.7 and the resulting reaction product possessing an acid number of 5 to 80 mg KOH/g.

11. The pigmented aqueous basecoat material as claimed in claim 10, wherein the tetracarboxylic dianhydride (a1) is 4,4-oxydiphthalic anhydride or 4,4-(4,4-iso-propylidenediphenoxy)bis(phthalic anhydride).

12. A polyether-based reaction product which is preparable by reaction of (a1) at least one tetracarboxylic dianhydride of the general structural formula (I) ##STR00010## in which X.sub.1 is a bond or an aliphatic, aromatic or araliphatic radical with (b) at least one polyether of the general structural formula (II) ##STR00011## in which R is a C.sub.3 to C.sub.6 alkylene radical and n is selected accordingly such that the polyether (b) possesses a number-average molecular weight of 500 to 5000 g/mol, the components (a) and (b) being used in the reaction in a molar ratio of 0.7/2.3 to 1.6/1.7 and the resulting reaction product possessing an acid number of 5 to 80 mg KOH/g.

13. The polyether-based reaction product as claimed in claim 12, wherein the group X.sub.1 according to the general structural formula (I) is a radical comprising 1 to 30 carbon atoms.

14. The polyether-based reaction product as claimed in claim 12, wherein X.sub.1 is a bond and therefore corresponds to 4,4-oxydiphthalic anhydride or X.sub.1 is ##STR00012## and therefore corresponds to 4,4-(4,4-isopropylidenediphenoxy)bis(phthalic anhydride).

15. A method for improving the stonechip resistance of paint systems wherein the method comprises utilizing a pigmented aqueous basecoat material as claimed in claim 1.

16. A method for producing a multicoat paint system by (1) applying a pigmented aqueous basecoat material to a substrate, (2) forming a polymer film basecoat from the pigmented aqueous basecoat material applied in step (1), (3) applying a clearcoat material to the resultant polymer film basecoat, and subsequently (4) curing the polymer film basecoat together with the clearcoat material, wherein the pigmented aqueous basecoat material as claimed in claim 1 is used in step (1).

17. The method as claimed in claim 16, wherein the substrate from step (1) is a metallic substrate coated with a cured electrocoat, and all coats applied to the electrocoat are cured jointly.

18. The method as claimed in claim 16, wherein the substrate from step (1) is a metal or plastics substrate.

19. A multicoat paint system producible by the method as claimed in claim 16.

20. The polyether-based reaction product as claimed in claim 13, wherein the group X.sub.1 according to the general structural formula (I) is a radical comprising 1 to 16 carbon atoms.

Description

EXAMPLES

[0183] Determination of the Number-Average Molecular Weight:

[0184] The number-average molecular weight was determined by means of vapor pressure osmosis. Measurement took place using a vapor pressure osmometer (model 10.00 from Knauer) on concentration series of the test component in toluene at 50 C. with benzophenone as calibration compound for the determination of the experimental calibration constant of the instrument used (according to E. Schrdder, G. Mller, K.-F. Arndt, Leitfaden der Polymercharakterisierung [Principles of polymer characterization], Academy-Verlag, Berlin, pp. 47-54, 1982, where the calibration compound used was in fact benzil).

[0185] Production of Inventive Reaction Products (IR) and Also of Reaction Products Used for Comparison (CR):

[0186] IR1:

[0187] In a 4 I stainless steel reactor equipped with anchor stirrer, thermometer, condenser, thermometer for overhead temperature measurement, 128.1 g of pyromellitic dianhydride (CAS No. 89-32-7, from Lonza) (0.5873 mol) and 2349.9 g of linear PolyTHF2000 (from BASF SE) with an OH number (OH number determined in accordance with DIN 53240) of 56.1 mg KOH/g (1.1750 mol) and 50.0 g of cyclohexane in the presence of 2.0 g of di-n-butyltin oxide (Axion CS 2455, from Chemtura) were heated to a product temperature of 130 C. and maintained at this temperature.

[0188] After about three hours, the reaction mixture was clear and an acid number was determined for the first time. The batch was held at 130 C. for three hours more until the acid number was 26.3 mg KOH/g (theory: 26.6 mg KOH/g).

[0189] Cyclohexane was distilled off under reduced pressure at 130 C. with stirring. Gas chromatography found a cyclohexane content of less than 0.15 wt %.

[0190] The polymer, which is initially liquid at room temperature, begins to crystallize after three days. The solid polymer is easily melted at a temperature of 80 C. and remains liquid for at least two hours even at room temperature, and so can easily be added to a coating formulation in this state.

[0191] Solids content (130 C., 60 min, 1 g): 99.9%

[0192] Acid number: 26.3 mg KOH/g

[0193] Number-average molecular weight (vapor pressure osmosis): 4100 g/mol

[0194] Viscosity (resin:butyl glycol (from BASF SE)=2:1): 3100 mPa.Math.s (measured at 23 C. using a Brookfield CAP 2000+rotary viscometer, spindle 3, shear rate: 2500 s.sup.1)

[0195] I R2:

[0196] In a 4 I stainless steel reactor equipped with anchor stirrer, thermometer, condenser, thermometer for overhead temperature measurement, 89.8 g of pyromellitic dianhydride (CAS No. 89-32-7, from Lonza) (0.4117 mol) and 2388.2 g of linear PolyTHF2900 (Terathane 2900, from Invista) with an OH number (OH number determined in accordance with DIN 53240) of 38.7 mg KOH/g (0.8235 mol) and 20.0 g of cyclohexane in the presence of 2.0 g of di-n-butyltin oxide (Axion CS 2455, from Chemtura) were heated to a product temperature of 130 C. and maintained at this temperature.

[0197] After about four hours, the reaction mixture was clear and an acid number was determined for the first time. The batch was held at 130 C. for three hours more until the acid number was 19.0 mg KOH/g (theory: 18.6 mg KOH/g).

[0198] Cyclohexane was distilled off under reduced pressure at 130 C. with stirring. Gas chromatography found a cyclohexane content of less than 0.1 wt %.

[0199] The polymer, which is initially liquid at room temperature, begins to crystallize after two days. The solid polymer is easily melted at a temperature of 80 C. and remains liquid for at least two hours even at room temperature, and so can easily be added to a coating formulation in this state.

[0200] Solids content (130 C., 60 min, 1 g): 100.0%

[0201] Acid number: 19.0 mg KOH/g

[0202] Number-average molecular weight (vapor pressure osmosis): 5800 g/mol

[0203] Viscosity (resin:butyl glycol (from BASF SE)=2:1): 7500 mPa.Math.s (measured at 23 C. using a Brookfield CAP 2000+rotary viscometer, spindle 3, shear rate: 1250 s.sup.1)

[0204] I R3:

[0205] In a 4 I stainless steel reactor equipped with anchor stirrer, thermometer, condenser, thermometer for overhead temperature measurement, 285.3 g of 4,4-(4,4-isopropylidenediphenoxy)bis(phthalic anhydride) (CAS No. 38103-06-9, from Changzhou Sunlight Pharmaceutical Co.) (0.5481 mol) and 2192.7 g of linear PolyTHF2000 (from BASF SE) with an OH number (OH number determined in accordance with DIN 53240) of 56.1 mg KOH/g (1.0963 mol) and 20.0 g of cyclohexane in the presence of 2.0 g of di-n-butyltin oxide (Axion CS 2455, from Chemtura) were heated to a product temperature of 130 C. and maintained at this temperature.

[0206] After about four hours, the reaction mixture was clear and an acid number was determined for the first time. The batch was held at 130 C. for three hours more until the acid number was 24.6 mg KOH/g (theory: 24.8 mg KOH/g).

[0207] Cyclohexane was distilled off under reduced pressure at 130 C. with stirring. Gas chromatography found a cyclohexane content of less than 0.15 wt %.

[0208] The polymer, which is initially liquid at room temperature, begins to crystallize after a few hours. The solid polymer is easily melted at a temperature of 80 C. and remains liquid for at least two hours even at room temperature, and so can easily be added to a coating formulation in this state.

[0209] Solids content (130 C., 60 min, 1 g): 99.9%

[0210] Acid number: 24.6 mg KOH/g

[0211] Number-average molecular weight (vapor pressure osmosis): 4300 g/mol

[0212] Viscosity (resin:butyl glycol (from BASF SE)=2:1): 135 mPa.Math.s (measured at 23 C. using a Brookfield CAP 2000+rotary viscometer, spindle 3, shear rate: 10 000 s.sup.1)

[0213] I R4:

[0214] In a 4 I stainless steel reactor equipped with anchor stirrer, thermometer, condenser, thermometer for overhead temperature measurement, 178.3 g of 4,4-oxydiphthalic anhydride) (CAS No. 1823-59-2, from Changzhou Sunlight Pharmaceutical Co.) (0.5748 mol) and 2299.7 g of linear PolyTHF2000 (from BASF SE) with an OH number (OH number determined in accordance with DIN 53240) of 56.1 mg KOH/g (1.1498 mol) and 20.0 g of cyclohexane in the presence of 2.0 g of di-n-butyltin oxide (Axion CS 2455, from Chemtura) were heated to a product temperature of 130 C. and maintained at this temperature.

[0215] After about four hours, the reaction mixture was clear and an acid number was determined for the first time. The batch was held at 130 C. for three hours more until the acid number was 26.2 mg KOH/g (theory: 26.0 mg KOH/g).

[0216] Cyclohexane was distilled off under reduced pressure at 130 C. with stirring. Gas chromatography found a cyclohexane content of less than 0.1 wt %.

[0217] The polymer, which is initially liquid at room temperature, begins to crystallize after one day. The solid polymer is easily melted at a temperature of 80 C. and remains liquid for at least two hours even at room temperature, and so can easily be added to a coating formulation in this state.

[0218] Solids content (130 C., 60 min, 1 g): 100.0%

[0219] Acid number: 26.2 mg KOH/g

[0220] Number-average molecular weight (vapor pressure osmosis): 4100 g/mol

[0221] Viscosity (resin:butyl glycol (from BASF SE)=2:1): 5200 mPa.Math.s (measured at 23 C. using a Brookfield CAP 2000+rotary viscometer, spindle 3, shear rate: 1250 s.sup.1)

[0222] I R5:

[0223] In a 4 I stainless steel reactor equipped with anchor stirrer, thermometer, condenser, thermometer for overhead temperature measurement, 115.8 g of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CAS No. 4415-87-6, from Synthon Chemicals) (0.5905 mol) and 2362.2 g of linear PolyTHF2000 (from BASF SE) with an OH number (OH number determined in accordance with DIN 53240) of 56.1 mg KOH/g (1.1811 mol) and 20.0 g of cyclohexane in the presence of 2.0 g of di-n-butyltin oxide (Axion CS 2455, from Chemtura) were heated to a product temperature of 130 C. and maintained at this temperature.

[0224] After about three hours, the reaction mixture was clear and an acid number was determined for the first time. The batch was held at 130 C. for three hours more until the acid number was 26.4 mg KOH/g (theory: 26.7 mg KOH/g).

[0225] Cyclohexane was distilled off under reduced pressure at 130 C. with stirring. Gas chromatography found a cyclohexane content of less than 0.15 wt %.

[0226] The polymer, which is initially liquid at room temperature, begins to crystallize after one day. The solid polymer is easily melted at a temperature of 80 C. and remains liquid for at least two hours even at room temperature, and so can easily be added to a coating formulation in this state.

[0227] Solids content (130 C., 60 min, 1 g): 99.9%

[0228] Acid number: 26.4 mg KOH/g

[0229] Number-average molecular weight (vapor pressure osmosis): 4100 g/mol

[0230] Viscosity (resin:butyl glycol (from BASF SE)=2:1): 3300 mPa.Math.s (measured at 23 C. using a Brookfield CAP 2000+rotary viscometer, spindle 3, shear rate: 2500 s.sup.1)

[0231] I R6:

[0232] In a 4 I stainless steel reactor equipped with anchor stirrer, thermometer, condenser, thermometer for overhead temperature measurement, 141.5 g of bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (CAS No. 1719-83-1, from SigmaAldrich) (0.57 mol) and 2280.0 g of linear PolyTHF2000 (from BASF SE) with an OH number (OH number determined in accordance with DIN 53240) of 56.1 mg KOH/g (1.14 mol) and 20.0 g of cyclohexane in the presence of 2.0 g of di-n-butyltin oxide (Axion CS 2455, from Chemtura) were heated to a product temperature of 130 C. and maintained at this temperature.

[0233] After about three hours, the reaction mixture was clear and an acid number was determined for the first time. The batch was held at 130 C. for three hours more until the acid number was 25.9 mg KOH/g (theory: 26.4 mg KOH/g).

[0234] Cyclohexane was distilled off under reduced pressure at 130 C. with stirring. Gas chromatography found a cyclohexane content of less than 0.15 wt %.

[0235] The polymer, which is initially liquid at room temperature, begins to crystallize after one day. The solid polymer is easily melted at a temperature of 80 C. and remains liquid for at least two hours even at room temperature, and so can easily be added to a coating formulation in this state.

[0236] Solids content (130 C., 60 min, 1 g): 99.9%

[0237] Acid number: 25.9 mg KOH/g

[0238] Number-average molecular weight (vapor pressure osmosis): 4000 g/mol

[0239] Viscosity (resin:butyl glycol (from BASF SE)=2:1): 3700 mPa.Math.s (measured at 23 C. using a Brookfield CAP 2000+rotary viscometer, spindle 3, shear rate: 2500 s.sup.1)

[0240] I R7:

[0241] In a 4 I stainless steel reactor equipped with anchor stirrer, thermometer, condenser, thermometer for overhead temperature measurement, 180.8 g of benzophenonetetracarboxylic dianhydride (CAS No. 2421-28-5, from SigmaAldrich) (0.561 mol) and 2244.0 g of linear PolyTHF2000 (from BASF SE) with an OH number (OH number determined in accordance with DIN 53240) of 56.1 mg KOH/g (1.112 mol) and 20.0 g of cyclohexane in the presence of 2.0 g of di-n-butyltin oxide (Axion CS 2455, from Chemtura) were heated to a product temperature of 130 C. and maintained at this temperature.

[0242] After about three hours, the reaction mixture was clear and an acid number was determined for the first time. The batch was held at 130 C. for three hours more until the acid number was 25.7 mg KOH/g (theory: 26.0 mg KOH/g).

[0243] Cyclohexane was distilled off under reduced pressure at 130 C. with stirring. Gas chromatography found a cyclohexane content of less than 0.15 wt %.

[0244] The polymer, which is initially liquid at room temperature, begins to crystallize after one day. The solid polymer is easily melted at a temperature of 80 C. and remains liquid for at least two hours even at room temperature, and so can easily be added to a coating formulation in this state.

[0245] Solids content (130 C., 60 min, 1 g): 99.9%

[0246] Acid number: 25.7 mg KOH/g

[0247] Number-average molecular weight (vapor pressure osmosis): 4100 g/mol

[0248] Viscosity (resin:butyl glycol (from BASF SE)=2:1): 4200 mPa.Math.s (measured at 23 C. using a Brookfield CAP 2000+rotary viscometer, spindle 3, shear rate: 2500 s.sup.1)

[0249] CR1:

[0250] A polyester prepared as per example D, column 16, lines 37 to 59 of DE 4009858 A served as reaction product used for comparison, butyl glycol being used as organic solvent instead of butanol, that is to say butyl glycol and water are present as solvents. The corresponding dispersion of the polyester has a solids content of 60 wt %.

[0251] Preparation of Aqueous Basecoat Materials

[0252] The following should be taken into account regarding formulation constituents and amounts thereof as indicated in the tables hereinafter. When reference is made to a commercial product or to a preparation protocol described elsewhere, the reference, independently of the principal designation selected for the constituent in question, is to precisely this commercial product or precisely the product prepared with the referenced protocol.

[0253] 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).

[0254] 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, as 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).

[0255] All proportions indicated in the tables are parts by weight.

[0256] Preparation of a Non-Inventive Waterborne Basecoat Material C1 Which can be Applied Directly as a Coloring Coat to the Cathodic Electrocoat System (CES).

[0257] The components listed under Aqueous phase in table A were stirred together in the order stated to form an aqueous mixture. In the next step, an organic mixture was prepared from the components listed under Organic phase. The organic mixture was added to the aqueous mixture. The combined mixtures were then stirred for 10 minutes and adjusted using deionized water and dimethylethanolamine to a pH of 8 and to a spray viscosity of 58 mPa.Math.s under a shearing load of 1000 s.sup.1, measured using a rotational viscometer (Rheomat RM 180 instrument from Mettler-Toledo) at 23 C.

TABLE-US-00001 TABLE A Waterborne basecoat material C1 Component Parts by weight Aqueous phase Aqueous solution of 3% sodium lithium 27 magnesium phyllosilicate Laponite RD (from Altana-Byk) and 3% Pluriol P900 (from BASF SE) Deionized water 15.9 Butyl glycol (from BASF SE) 3.5 Hydroxy-functional, polyurethane-modified 2.4 polyacrylate, prepared as per page 7, line 55 to page 8, line 23 of DE 4437535 A1 50 wt % strength solution of Rheovis PU 1250 0.2 (BASF SE) in butyl glycol; rheological agent CR1 2.5 TMDD 50% BG (from BASF SE), 52% strength 1.2 solution of 2,4,7,9-tetramethyl-5-decyne-4,7-diol in butyl glycol Luwipal 052 (from BASF SE), melamine- 4.7 formaldehyde resin 10% strength solution of N,N- 0.5 dimethylethanolamine (from BASF SE) in water Polyurethane-based graft copolymer; prepared in 19.6 analogy to DE 19948004 A1 (page 27 - example 2) Isopropanol (from BASF SE) 1.4 Byk-347 (from Altana-Byk) 0.5 Pluriol P900 (from BASF SE) 0.3 Tinuvin 384-2 (from BASF SE) 0.6 Tinuvin 123 (from BASF SE) 0.3 Carbon black paste 4.3 Blue paste 11.4 Mica slurry 2.8 Organic phase Aluminum pigment (from Altana-Eckart) 0.3 Butyl glycol (from BASF SE) 0.3 Polyurethane-based graft copolymer; prepared in 0.3 analogy to DE 19948004 A1 (page 27 - example 2)

[0258] Preparation of Blue Paste:

[0259] The blue paste was prepared from 69.8 parts by weight of an acrylated polyurethane dispersion prepared as per international patent application WO 91/15528, binder dispersion A, 12.5 parts by weight of Paliogen Blue L 6482, 1.5 parts by weight of dimethylethanolamine (10% strength in DI water), 1.2 parts by weight of a commercial polyether (Pluriol P900 from BASF SE), and 15 parts by weight of deionized water.

[0260] Preparation of Carbon Black Paste:

[0261] The carbon black paste was prepared from 25 parts by weight of an acrylated polyurethane dispersion prepared as per international patent application WO 91/15528, binder dispersion A, 10 parts by weight of carbon black, 0.1 part by weight of methyl isobutyl ketone, 1.36 parts by weight of dimethylethanolamine (10% strength in DI water), 2 parts by weight of a commercial polyether (Pluriol P900 from BASF SE), and 61.45 parts by weight of deionized water.

[0262] Preparation of the Mica Slurry:

[0263] The mica slurry was obtained by using a stirring element to mix 1.5 parts by weight of polyurethane-based graft copolymer, prepared in an analogy to DE 19948004 A1 (page 27example 2), and 1.3 parts by weight of the commercial Mica Mearlin Ext. Fine Violet 539V from Merck.

[0264] Preparation of the Inventive Waterborne Basecoat Materials I1-I7 Which can be Applied Directly as a Coloring Coat to the Cathodic Electrocoat System (CES).

[0265] The waterborne basecoat materials I1-I7 were prepared in analogy to table A, but using the reaction product IR1 (waterborne basecoat material I1), the reaction product IR2 (waterborne basecoat material I2), the reaction product IR3 (waterborne basecoat material I3), the reaction product IR4 (waterborne basecoat material I4), the reaction product IRS (waterborne basecoat material I5), the reaction product IR6 (waterborne basecoat material I6) or the reaction product IR7 (waterborne basecoat material I7) in place of CR1. The proportion used of the reaction product IR1 or IR2-IR7 was the same in each case, through compensation of the amount of solvent and/or through consideration of the solids content of the component to be added.

TABLE-US-00002 TABLE B Basecoat materials C1, I1-I7 Reaction product Waterborne basecoat material C1 CR1 Waterborne basecoat material I1 IR1 Waterborne basecoat material I2 IR2 Waterborne basecoat material I3 IR3 Waterborne basecoat material I4 IR4 Waterborne basecoat material I5 IR5 Waterborne basecoat material I6 IR6 Waterborne basecoat material I7 IR7

[0266] Comparison Between Waterborne Basecoat Materials C1 and I1-I7

[0267] Stonechip Resistance:

[0268] For the determination of the stonechip resistance, the multicoat paint systems were produced according to the following general protocol:

[0269] The substrate used was a steel panel with dimensions of 1020 cm, coated with a cathodic e-coat (cathodic electrocoat).

[0270] Applied to this panel first of all was the respective basecoat material (table B), applied pneumatically with a target film thickness (dry film thickness) at 20 micrometers. After the basecoat had been flashed at room temperature for 1 minute, it was subjected to interim drying in a forced air oven at 70 C. for 10 minutes. Over the interim-dried waterborne basecoat, a customary two-component clearcoat material (Progloss 372 from BASF Coatings GmbH) was applied with a target film thickness (dry film thickness) at 40 micrometers. The resulting clearcoat was flashed at room temperature for 20 minutes. The waterborne basecoat and the clearcoat were subsequently cured in a forced air oven at 160 C. for 30 minutes.

[0271] The resulting multicoat paint systems were tested for their stonechip resistance. This was done using the stonechip test of DIN 55966-1. The results of the stonechip test were assessed in accordance with DIN EN ISO 20567-1. Lower values represent better stonechip resistance.

[0272] The results are found in table 1. The waterborne basecoat material (WBM) detail indicates which WBM was used in the particular multicoat paint system.

TABLE-US-00003 TABLE 1 Stonechip resistance of waterborne basecoat materials C1 and I1-I7 WBM Stonechip outcome C1 2.5 I1 1.5 I2 1.5 I3 1.5 I4 1.5 I5 1.5 I6 1.5 I7 1.5

[0273] The results emphasize that the use of the inventive reaction products in basecoat materials significantly increases the stonechip resistance by comparison with the waterborne basecoat material 1.

[0274] Preparation of a Noninventive Waterborne Basecoat Material C2 Which can be Applied Directly as a Noncoloring Coat to the Cathodic Electrocoat System (CES).

[0275] The components listed under Aqueous phase in table C were stirred together in the order stated to form an aqueous mixture. The combined mixtures were then stirred for 10 minutes and adjusted using deionized water and dimethylethanolamine to a pH of 8 and to a spray viscosity of 58 mPa.Math.s under a shearing load of 1000 s.sup.1, measured using a rotational viscometer (Rheomat RM 180 instrument from Mettler-Toledo) at 23 C.

TABLE-US-00004 TABLE C Waterborne basecoat material C2 Component Aqueous phase Parts by weight Aqueous solution of 3% sodium lithium 14 magnesium phyllosilicate Laponite RD (from Altana-Byk) and 3% Pluriol P900 (from BASF SE) Deionized water 16 Butyl glycol (from BASF SE) 1.4 CR1 2.3 10 wt % strength solution of Rheovis AS 1130 6 (BASF SE) in water; rheological agent TMDD 50% BG (from BASF SE), 52% strength 1.6 solution of 2,4,7,9-tetramethyl-5-decyne-4,7-diol in butyl glycol Cymel 1133 (from Cytec), melamine- 5.9 formaldehyde resin 10% strength solution of N,N- 0.4 dimethylethanolamine (from BASF SE) in water Polyurethane dispersion - prepared as per 20 WO 92/15405 (page 14, line 13 to page 15, line 28) 2-Ethylhexanol (from BASF SE) 3.5 Triisobutyl phosphate (from Bayer) 2.5 Nacure 2500 (from King Industries) 0.6 White paste 24 Carbon black paste 1.8

[0276] Preparation of the Carbon Black Paste:

[0277] The carbon black paste was prepared from 25 parts by weight of an acrylated polyurethane dispersion prepared as per international patent application WO 91/15528, binder dispersion A, 10 parts by weight of carbon black, 0.1 part by weight of methyl isobutyl ketone, 1.36 parts by weight of dimethylethanolamine (10% strength in DI water), 2 parts by weight of a commercial polyether (Pluriol P900 from BASF SE), and 61.45 parts by weight of deionized water.

[0278] Preparation of the White Paste:

[0279] The white paste was prepared from 43 parts by weight of an acrylated polyurethane dispersion prepared as per international patent application WO 91/15528, binder dispersion A, 50 parts by weight of titanium rutile 2310, 3 parts by weight of 1-propoxy-2-propanol, and 4 parts by weight of deionized water.

[0280] Preparation of the Inventive Waterborne Basecoat Materials I8-I14 Which can be Applied Directly as a Noncoloring Coat to the Cathodic Electrocoat System (CES).

[0281] The waterborne basecoat materials I8-I14 were prepared in analogy to table C, but using the reaction product IR1 (waterborne basecoat material I8), the reaction product IR2 (waterborne basecoat material I9), the reaction product IR3 (waterborne basecoat material I10), the reaction product IR4 (waterborne basecoat material I11), the reaction product IRS (waterborne basecoat material I12), the reaction product IR6 (waterborne basecoat material I13) or the reaction product IR7 (waterborne basecoat material I14) in place of CR1. The proportion used of the reaction product IR1 or IR2-IR7 was the same in each case, through compensation of the amount of solvent and/or through consideration of the solids content of the component to be added.

TABLE-US-00005 TABLE D Basecoat materials C2, I8-I14 Reaction product Waterborne basecoat material C2 CR1 Waterborne basecoat material I8 IR1 Waterborne basecoat material I9 IR2 Waterborne basecoat material I10 IR3 Waterborne basecoat material I11 IR4 Waterborne basecoat material I12 IR5 Waterborne basecoat material I13 IR6 Waterborne basecoat material I14 IR7

[0282] Preparation of a Noninventive Waterborne Basecoat Material C3 Which can be Applied Directly as a Coloring Coat to Waterborne Basecoat Materials C2 and I8-I14.

[0283] The components listed under Aqueous phase in table E were stirred together in the order stated to form an aqueous mixture. In the next step, an organic mixture was prepared from the components listed under Organic phase. The organic mixture was added to the aqueous mixture. The combined mixtures were then stirred for 10 minutes and adjusted using deionized water and dimethylethanolamine to a pH of 8 and to a spray viscosity of 58 mPa.Math.s under a shearing load of 1000 s.sup.1, measured using a rotational viscometer (Rheomat RM 180 instrument from Mettler-Toledo) at 23 C.

TABLE-US-00006 TABLE E Waterborne basecoat material C3 Component Parts by weight Aqueous phase Aqueous solution of 3% sodium lithium 20.35 magnesium phyllosilicate Laponite RD (from Altana-Byk) and 3% Pluriol P900 (from BASF SE) Deionized water 17.27 Butyl glycol (from BASF SE) 2.439 Hydroxy-functional, polyurethane-modified 2.829 polyacrylate, prepared as per page 7, line 55 to page 8, line 23 of DE 4437535 A1 50 wt % strength solution of Rheovis PU 1250 0.234 (BASF SE) in butyl glycol; rheological agent 10 wt % strength solution of Rheovis AS 1130 4.976 (BASF SE) in water; rheological agent TMDD 50% BG (from BASF SE), 52% strength 1.317 solution of 2,4,7,9-tetramethyl-5-decyne-4,7-diol in butyl glycol Cymel 1133 (from Cytec), melamine- 3.512 formaldehyde resin 10% strength solution of N,N- 1.356 dimethylethanolamine (from BASF SE) in water Polyurethane dispersion - prepared as per WO 24.976 92/15405 (page 14, line 13 to page 15, line 28) Isopropanol (from BASF SE) 1.659 Byk-347 (from Altana-Byk) 0.537 Pluriol P900 (from BASF SE) 0.39 2-Ethylhexanol (from BASF SE) 1.854 Triisobutyl phosphate (from Bayer) 1.151 Nacure 2500 (from King Industries) 0.39 Tinuvin 384-2 (from BASF SE) 0.605 Tinuvin 123 (from BASF SE) 0.39 Blue paste 0.605 Organic phase Aluminum pigment 1 (from Altana-Eckart) 4.585 Aluminum pigment 2 (from Altana-Eckart) 0.907 Butyl glycol (from BASF SE) 3.834 Polyurethane-based graft copolymer; prepared in 3.834 analogy to DE 19948004 A1 (page 27 - example 2)

[0284] Preparation of the Blue Paste:

[0285] The blue paste was prepared from 69.8 parts by weight of an acrylated polyurethane dispersion prepared as per international patent application WO 91/15528, binder dispersion A, 12.5 parts by weight of Paliogen Blue L 6482, 1.5 parts by weight of dimethylethanolamine (10% strength in DI water), 1.2 parts by weight of a commercial polyether (Pluriol P900 from BASF SE), and 15 parts by weight of deionized water.

[0286] Comparison Between Waterborne Basecoat Materials C2 and I8-I14

[0287] For the determination of the stonechip resistance, the multicoat paint systems were produced according to the following general protocol:

[0288] The substrate used was a steel panel with dimensions of 1020 cm, coated with a cathodic e-coat.

[0289] The respective basecoat material (table D) was first of all applied pneumatically to this panel with a target film thickness (dry film thickness) at 15 micrometers. After flashing of the basecoat material at room temperature for 4 minutes, the waterborne basecoat material C3 was applied pneumatically in a target film thickness (dry film thickness) at 15 micrometers, then flashed at room temperature for 4 minutes and then subjected to interim drying in a forced air oven at 70 C. for 10 minutes. Over the interim-dried waterborne basecoat, a customary two-component clearcoat material (Progloss 372 from BASF Coatings GmbH) was applied with a target film thickness (dry film thickness) at 40 micrometers. The resulting clearcoat was flashed at room temperature for 20 minutes. The waterborne basecoat and the clearcoat were subsequently cured in a forced air oven at 160 C. for 30 minutes.

[0290] The resulting multicoat paint systems were investigated for their stonechip resistance. For this purpose the stonechip test of DIN 55966-1 was carried out. The results of the stonechip test were assessed in accordance with DIN EN ISO 20567-1. Lower values represent better stonechip resistance.

[0291] The results are found in table 2. The specification of the waterborne basecoat material (WBM) indicates in each case which WBM was used in the respective multicoat paint system.

TABLE-US-00007 TABLE 2 Stonechip resistance of the waterborne basecoat materials C2 and I8-I14 WBM Stonechip result C2 + C3 2.5 I8 + C3 1.5 I9 + C3 1.5 I10 + C3 1.5 I11 + C3 1.5 I12 + C3 1.5 I13 + C3 1.5 I14 + C3 1.5

[0292] The results again emphasize that the use of the inventive reaction products in basecoat materials significantly increases the stonechip resistance in comparison to noninventive systems.