Dimer fatty acid-containing reaction product and coating composition comprising the reaction product

Abstract

The present invention relates to a reaction product preparable by reacting (a) dimer fatty acids with (b) at least one compound (b) of the general structural formula (I) ##STR00001## where R is a C.sub.3 to C.sub.6 alkylene radical and n correspondingly is selected such that the compound (b) possesses a number-average molecular weight of 120 to 445 g/mol, components (a) and (b) are used in a molar ratio of 0.7/2.3 to 1.6/1.7, and the resulting reaction product possesses a number-average molecular weight of 600 to 4000 g/mol and an acid number of less than 10 mg KOH/g. The invention further relates to a pigmented aqueous basecoat material which comprises this reaction product, and to the use of the reaction product in pigmented aqueous basecoat materials for improving adhesion. The present invention further relates to a method for producing multicoat paint systems, and also to the multicoat paint systems producible by means of said method.

Claims

1. A pigmented aqueous basecoat material which comprises a pigment and at least one reaction product prepared by reacting: (a) at least one dimer fatty acid(s) with (b) at least one compound of the general structural formula (I): ##STR00004## where R is a C.sub.3 to C.sub.6 alkylene radical and n correspondingly is selected such that the compound (b) possesses a number-average molecular weight of 120 to 445 g/mol, components (a) and (b) are used in a molar ratio of 0.7/2.3 to 1.6/1.7, and the resulting reaction product possesses a number-average molecular weight of 600 to 4000 g/mol and an acid number of less than 10 mg KOH/g.

2. The pigmented aqueous basecoat material as claimed in claim 1, wherein the dimer fatty acid(s) used consist of at least 90 wt % of dimeric molecules, less than 5 wt % of trimeric molecules, less than 5 wt % of monomeric molecules, and less than 5 wt % of byproducts.

3. The pigmented aqueous basecoat material as claimed in claim 1, wherein the compound (b) possesses a number-average molecular weight of 140 to 425 g/mol.

4. The pigmented aqueous basecoat material as claimed in claim 1, wherein the group R as per the general structural formula (I) comprises isopropylene radicals or tetramethylene radicals and the compound (b) possesses a number-average molecular weight of 170 to 350 g/mol.

5. The pigmented aqueous basecoat material as claimed in claim 1, wherein components (a) and (b) are used in a molar ratio of 0.9/2.1 to 1.5/1.8.

6. The pigmented aqueous basecoat material as claimed in claim 1, wherein said reaction product possesses a number-average molecular weight of 800 to 3500 g/mol.

7. The pigmented aqueous basecoat material as claimed in claim 1, wherein the sum total of weight-percentage fractions of the at least one reaction product, based on the total weight of the pigmented aqueous basecoat material(s) is 0.1 to 30 wt %.

8. The pigmented aqueous basecoat material as claimed in claim 1, which further comprises at least one polyurethane resin.

9. The pigmented aqueous basecoat material as claimed in claim 1, which further comprises a melamine resin and a hydroxyl-containing polyurethane resin, wherein said hydroxyl-containing polyurethane resin is produced by grafting olefinically unsaturated monomers.

10. A method for improving the adhesion of a pigmented basecoat material comprising incorporating a pigment and a reaction product into a basecoat material wherein said reaction is prepared by reacting: (a) at least one dimer fatty acid(s) with (b) at least one compound of the general structural formula (I): ##STR00005## where R is a C.sub.3 to C.sub.6 alkylene radical and n correspondingly is selected such that the compound (b) possesses a number-average molecular weight of 120 to 445 g/mol, components (a) and (b) are used in a molar ratio of 0.7/2.3 to 1.6/1.7, and the resulting reaction product possesses a number-average molecular weight of 600 to 4000 g/mol and an acid number of less than 10 mg KOH/g.

11. A method for producing a multiple-coat paint system, comprising (1) applying a pigmented aqueous basecoat material according to claim 1 to a substrate, (2) forming a polymer film from the coating material applied in stage (1) thus forming a basecoat film, (3) applying a clearcoat material to the basecoat film, and subsequently (4) curing the basecoat film together with the clearcoat film.

12. The method as claimed in claim 11, wherein the substrate from stage (1) is a multicoat paint system which possesses defects.

13. A multicoat paint system producible by the method according to claim 12.

14. A multicoat paint system producible by the method according to claim 11.

Description

EXAMPLES

(1) Specification of Particular Components and Measurement Methods

(2) Dimer Fatty Acid:

(3) The dimer fatty acid used contains less than 1.5 wt % trimeric molecules, 98 wt % dimeric molecules, and less than 0.3 wt % fatty acid (monomer). It is prepared on the basis of linolenic, linoleic, and oleic acids (Pripol™ 1012-LQ-(GD) (from Croda)).

(4) Polyester 1 (P1):

(5) Prepared as per example D, column 16, lines 37 to 59 of DE 4009858 A. The corresponding polyester solution has a solids content of 60 wt %, the solvent used being butyl glycol rather than butanol, so the solvents present are primarily butyl glycol and water.

(6) Determination of the Number-Average Molecular Weight:

(7) 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 component under investigation in toluene at 50° C., with benzophenone as calibration substance for the determination of the experimental calibration constant of the instrument employed (in accordance with E. Schroder, G. Müller, K.-F. Arndt, “Leitfaden der Polymercharakterisierung”, Akademie-Verlag, Berlin, pp. 47-54, 1982, in which benzil was used as calibration substance).

(8) Preparation of Reaction Products of the Invention

(9) Inventive Reaction Product 1 (IR1):

(10) In a 4 l stainless-steel reactor, equipped with anchor stirrer, thermometer, condenser, thermometer for overhead temperature measurement, and water separator, 799.2 g of linear diolic PolyTHF250 (BASF SE) with an OH number of 448.9 mg KOH/g (3.1968 mol), 926.0 g of dimer fatty acid (1.5985 mol), and 53.4 g of xylene were heated to 100° C. in the presence of 1.4 g of di-n-butyltin oxide (Axion® CS 2455, from Chemtura). Heating was continued slowly until the onset of the condensation. With a maximum overhead temperature of 85° C., heating was then continued in steps up to 207° C. The progress of the reaction was monitored via determination of the acid number. When an acid number of 1.5 mg KOH/g was reached, xylene still present was removed by vacuum distillation. This gave a resin which is liquid at room temperature. Gas chromatography found a xylene content of less than 0.1%.

(11) Amount of condensate (water): 58.2 g

(12) Acid number: 0.6 mg KOH/g

(13) Solids content (GC): 100.0%

(14) Number-average molecular weight (vapor pressure osmosis): 990 g/mol

(15) Viscosity (resin:xylene=2:1): 92 mPas, (measured at 23° C. using a rotational viscometer from Brookfield, model CAP 2000+, spindle 3, shear rate: 10 000 s.sup.−1)

(16) Inventive Reaction Product 2 (IR2):

(17) In a 4 l stainless-steel reactor, equipped with anchor stirrer, thermometer, condenser, thermometer for overhead temperature measurement, and water separator, 708.0 g of linear diolic PolyTHF250 (BASF SE) with an OH number of 448.9 mg KOH/g (2.8320 mol), 1230.4 g of dimer fatty acid (2.1239 mol), and 60.0 g of xylene were heated to 100° C. in the presence of 1.6 g of di-n-butyltin oxide (Axion® CS 2455, from Chemtura). Heating was continued slowly until the onset of the condensation. With a maximum overhead temperature of 85° C., heating was then continued in steps up to 207° C. The progress of the reaction was monitored via determination of the acid number. When an acid number of 1.5 mg KOH/g was reached, xylene still present was removed by vacuum distillation. This gave a resin which is waxlike at room temperature. Gas chromatography found a xylene content of less than 0.1%.

(18) Amount of condensate (water): 77.0 g

(19) Acid number: 0.4 mg KOH/g

(20) Solids content (GC): 100.0%

(21) Number-average molecular weight (vapor pressure

(22) osmosis): 2630 g/mol

(23) Viscosity (resin:xylene=2:1): 221 mPas, (measured at 23° C. using a rotational viscometer from

(24) Brookfield, model CAP 2000+, spindle 3, shear rate: 10 000 s.sup.−1)

(25) Production of Aqueous Basecoat Materials

(26) Production of a Silver Comparative Waterborne Basecoat 1 (C1)

(27) The components listed under “aqueous phase” in table A were stirred together in the order stated to give 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 was then stirred for 10 minutes and adjusted using deionized water and dimethylethanolamine to a pH of 8 and to a spray viscosity of 58 mPas under a shearing load of 1000 s.sup.−1, as measured using a rotational viscometer (Rheomat RM 180 instrument from Mettler-Toledo) at 23° C.

(28) TABLE-US-00001 TABLE A Parts by Component weight Aqueous phase 3% strength Na Mg phyllosilicate 26 solution Deionized water 13.6 Butyl glycol 2.8 Polyurethane-modified polyacrylate; 4.5 prepared as per page 7, line 55 to page 8, line 23 of DE 4437535 A 50% strength by weight solution of 0.6 Rheovis PU 1250 (BASF), rheological agent P1 3.2 Tensid S (surfactant BASF) 0.3 Melamine-formaldehyde resin (Cymel 203 4.1 from Cytec) 10% strength dimethylethanolamine in 0.3 water Polyurethane-based graft copolymer; 20.4 prepared as per page 19, line 44 to page 20, line 21 of DE 19948004 A Tensid S (surfactant BASF) 1.6 3% strength by weight aqueous Rheovis AS 3.9 S130 solution; rheological agent, available from BASF Organic phase Mixture of two commercial aluminum 6.2 pigments, available from Altana-Eckart Butyl glycol 7.5 P1 5

(29) Production of an Inventive Waterborne Basecoat Material 1 (I1)

(30) To produce the inventive waterborne basecoat material I1, a paint was produced as for the production of the comparative waterborne basecoat 1 (C1), using IR1, instead of the polyester P1, both in the aqueous phase and in the organic phase. IR1 was used here as an 80% strength solution in butyl glycol. Based on the solids fraction (nonvolatile fraction), the amount of IR1 used in I1 was the same as that of the polyester P1 used in C1. The different amounts of butyl glycol resulting from the different solids of dispersions P1 and IR1 were compensated in the formulation I1 by corresponding addition of butyl glycol.

(31) Production of an Inventive Waterborne Basecoat Material 2 (I2)

(32) To produce the inventive waterborne basecoat material I2, a paint was produced as for the production of the comparative waterborne basecoat 1 (C1) using IR2, instead of the polyester P1, both in the aqueous phase and in the organic phase. IR2 was used here as an 80% strength solution in butyl glycol. Based on the solids fraction (nonvolatile fraction), the amount of IR2 used in 12 was the same as that of the polyester P1 used in C1. The different amounts of butyl glycol resulting from the different solids of dispersions P1 and IR2 were compensated in the formulation 12 by corresponding addition of butyl glycol.

(33) Table 1 shows again the polyesters and reaction products, and their proportions (based on the total amount of the waterborne basecoat materials), used in waterborne basecoat materials C1, I1, and I2, as an overview.

(34) TABLE-US-00002 TABLE 1 Compositions of waterborne basecoat materials (WBM) C1, I1, and I2 WBM [wt %] polyester/reaction product C1 4.92 P1 I1 4.92 IR1 I2 4.92 IR2

(35) Production of Multicoat Paint Systems and Performance Investigation of the Multicoat Paint Systems

(36) For determining the stability with respect to the incidence of blisters and swelling after condensation-water storage, multicoat paint systems were produced in accordance with the following general instructions.

(37) A steel panel coated with a standard cathodic electrocoat (Cathoguard® 800 from BASF Coatings GmbH) and with dimensions of 10×20 cm was coated with a standard surfacer (ALG 670173—surfacer, medium-gray, from Hemmelrath). After preliminary drying of the aqueous surfacer at 80° C. over a period of 10 minutes, the surfacer was baked at a temperature of 190° C. over a period of 30 minutes.

(38) The respective waterborne basecoat material from table 1 was then applied pneumatically. The resulting waterborne basecoat film was flashed at room temperature for 2 minutes and subsequently dried in a forced-air oven at 70° C. for 10 minutes. A customary two-component clearcoat material (Progloss® 345 from BASF Coatings GmbH) was applied to the dried waterborne basecoat film. The resulting clearcoat film was flashed at room temperature for 20 minutes. The waterborne basecoat film and the clearcoat film were then cured in a forced-air oven at 160° C. for 30 minutes. The present system represents an overbaked original system and will be referred to below as the original finish.

(39) This original finish is abraded with abrasive paper and then the respective waterborne basecoat material from table 1 is applied pneumatically to this abraded original finish. The resulting waterborne basecoat film was flashed at room temperature for 2 minutes and subsequently dried in a forced-air oven at 70° C. for 10 minutes. A so-called 80° C. two-component clearcoat material (FF230500 2K refinish clearcoat, scratchproof, from BASF Coatings GmbH) was applied to the dried waterborne basecoat film. The resulting clearcoat film was flashed at room temperature for 20 minutes. The waterborne basecoat film and the clearcoat film were then cured in a forced-air oven at 80° C. for 30 minutes.

(40) The steel panels thus treated were 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. 24 hours after removal from the conditioning chamber, the panels were then inspected for blistering and swelling.

(41) The occurrence of blisters was assessed as follows through a combination of 2 values: The number of blisters was evaluated by a quantitative figure from 1 to 5, with m1 denoting very few and m5 very many blisters. The size of the blisters was evaluated by a size figure again from 1 to 5, with g1 denoting very small and g5 very large blisters. The designation m0g0 denotes, accordingly, a paint system which was blister-free after condensation-water storage, and in terms of blistering represents a “satisfactory” result.

(42) Table 2 shows the corresponding results for waterborne basecoat materials C1, I1, and I2.

(43) TABLE-US-00003 TABLE 2 Blistering and swelling of multicoat paint systems produced using waterborne basecoat materials C1, I1, and I2 WBM Blistering Swelling Evaluation C1 m5g1 none unsat I1 m0g0 none sat I2 m0g0 none sat Key: m = number of blisters g = size of blisters sat = satisfactory result unsat = unsatisfactory result

(44) The results confirm that when using the reaction products of the invention, blisters no longer occur after condensation-water exposure, and instances of swelling are no longer visible.

(45) Production of a Silver Comparative Waterborne Basecoat 2 (C2)

(46) The components listed under “aqueous phase” in table B 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 was then stirred for 10 minutes and adjusted using deionized water and dimethylethanolamine to a pH of 8 and to a spray viscosity of 58 mPas under a shearing load of 1000 s.sup.−1, as measured using a rotational viscometer (Rheomat RM 180 instrument from Mettler-Toledo) at 23° C.

(47) TABLE-US-00004 TABLE B Parts by Component weight Aqueous phase 3% strength Na Mg phyllosilicate 26 solution Deionized water 21.7 Butyl glycol 2.8 Polyurethane-modified polyacrylate; 4.5 prepared as per page 7, line 55 to page 8, line 23 of DE 4437535 A 50% strength by weight solution of 0.6 Rheovis PU 1250 (BASF), rheological agent P1 13.3 Tensid S (surfactant BASF) 0.3 Melamine-formaldehyde resin (Cymel 203 4.1 from Cytec) 10% strength dimethylethanolamine in 0.3 water Polyurethane-based graft copolymer; 1.8 prepared as per page 19, line 44 to page 20, line 21 of DE 19948004 A Tensid S (surfactant BASF) 1.6 3% strength by weight aqueous Rheovis AS 3.9 S130 solution; rheological agent, available from BASF Organic phase Mixture of two commercial aluminum 6.2 pigments, available from Altana-Eckart Butyl glycol 7.5 P1 5

(48) Production of an Inventive Waterborne Basecoat Material 3 (I3)

(49) To produce the inventive waterborne basecoat material I3, a paint was produced as for the production of the comparative waterborne basecoat 2 (C2), using IR1, instead of the polyester P1, both in the aqueous phase and in the organic phase. IR1 was used here as an 80% strength solution in butyl glycol. Based on the solids fraction (nonvolatile fraction), the amount of IR1 used in 13 was the same as that of the polyester P1 used in C2. The different amounts of butyl glycol resulting from the different solids of dispersions P1 and IR1 were compensated in the formulation 13 by corresponding addition of butyl glycol.

(50) Production of an Inventive Waterborne Basecoat Material 4 (I4)

(51) To produce the inventive waterborne basecoat material I4, a paint was produced as for the production of the comparative waterborne basecoat 2 (C2) using IR2, instead of the polyester P1, both in the aqueous phase and in the organic phase. IR2 was used here as an 80% strength solution in butyl glycol. Based on the solids fraction (nonvolatile fraction), the amount of IR2 used in 14 was the same as that of the polyester P1 used in C2. The different amounts of butyl glycol resulting from the different solids of dispersions P1 and IR2 were compensated in the formulation 14 by corresponding addition of butyl glycol.

(52) Table 3 shows again the polyesters and reaction products, and their proportions (based on the total amount of the waterborne basecoat materials), used in waterborne basecoat materials C2, I3, and I4, as an overview.

(53) TABLE-US-00005 TABLE 3 Compositions of waterborne basecoat materials C2, I3, and I4 WBM [wt %] Polyester/reaction product C2 10.98 P1 I3 10.98 IR1 I4 10.98 IR2

(54) Production of Multicoat Paint Systems and Performance Investigation of the Multicoat Paint Systems

(55) In analogy to the protocols set out above, corresponding multicoat paint systems (original finishes) were produced using waterborne basecoat materials C2, I3, and I4, and were abraded, and in turn recoated. This was followed in turn by the afore-described investigation of the blistering and swelling.

(56) Table 4 shows the corresponding results.

(57) TABLE-US-00006 TABLE 4 Blistering and swelling of multicoat paint systems produced using waterborne basecoat materials C2, I3, and I4 WBM Blistering Swelling Evaluation C2 m5g4 none unsat I3 m0g0 none sat I4 m0g0 none sat Key: m = number of blisters g = size of blisters sat = satisfactory result unsat = unsatisfactory result

(58) The results confirm that when using the reaction products of the invention, blisters no longer occur after condensation-water exposure, and instances of swelling are no longer visible. Furthermore, the properties are a distinct improvement on the use of a standard ester (P1).