Dimer fatty acid/dimer diol reaction product and use thereof in coating materials

Abstract

The present invention relates to a dimer fatty acid/dimer diol reaction product which is preparable by reacting (a) dimer fatty acids with (b) at least one dimer diol, where components (a) and (b) are used in a molar ratio of 0.7/2.3 to 1.3/1.7 and the resulting dimer fatty acid/dimer diol reaction product possesses a number-average molecular weight of 1200 to 5000 g/mol and an acid number <10 mg KOH/g. The invention further relates to a pigmented aqueous basecoat material which comprises this dimer fatty acid/dimer diol reaction product, and also to the use of said dimer fatty acid/dimer diol reaction product in pigmented aqueous basecoat materials. It relates, further, to a method for producing multicast paint systems, and also to the multicoat paint systems producible by means of said method. The present invention relates, furthermore, to the refinishing of defects on multicoat paint systems.

Claims

1. A method for producing a multiple-coat paint system, the method comprising: applying to a substrate a pigmented aqueous basecoat material which comprises a reaction product consisting of a dimer fatty acid and a dimer diol, which is obtained by reacting (a) said dimer fatty acid with (b) said dimer diol, wherein the dimer diol is prepared by (i) oligomerization of unsaturated fatty acids or esters thereof and subsequent hydrogenation of the acid or ester groups, or (ii) oligomerization of unsaturated fatty alcohols having 12 to 22 carbon atoms, where components (a) and (b) are reacted in a molar ratio of 0.7/2.3 to 1.3/1.7 and the resulting dimer fatty acid/dimer diol reaction product possesses a number-average molecular weight of 1200 to 5000 g/mol and an acid number <10 mg KOH/g; forming a polymer film from the coating material applied in (1); applying a clearcoat material to the resulting basecoat film; and subsequently curing the basecoat film together with the clearcoat film, and wherein said substrate is an automotive body or automotive component.

2. The method of claim 1, wherein the substrate from the applying (1) is a multicoat paint system which has defects.

3. The method of claim 1, wherein the substrate is an automotive body.

4. The method of claim 1, wherein the substrate is an automotive component.

5. The method of claim 1, wherein the dimer fatty acids and/or the dimer diols consist of at least 90 wt % of dimeric molecules, less than 5 wt % of trimeric molecules, and less than 5 wt % of monomeric molecules and of other byproducts and/or possess a hydroxyl functionality of 1.8 to 2.2.

6. The method of claim 1, wherein the dimer fatty acids are prepared from linolenic, linoleic and/or oleic acid and consist of 98 wt % of dimeric molecules, 1.5 wt % of trimeric molecules, and 0.5 wt % of monomeric molecules and of other byproducts.

7. The method of claim 1, wherein the dimer dial is prepared by (i) oligomerization of unsaturated fatty acids or esters thereof and subsequent hydrogenation of the acid or ester groups.

8. The method of claim 1, wherein components (a) and (b) are reacted in a molar ratio of 0.9/2.1 to 1.1/1.9.

9. The method of claim 1, wherein the dimer fatty acid/dimer diol reaction product has a number-average molecular weight of 1200 to 4000 g/mol.

10. The method of claim 1, wherein the dimer fatty acid/diner diol reaction product has an acid number of <5 mg KOH/g.

11. The method of claim 1, wherein the sum total of the weight-percentage fractions of all dimer fatty acid/dimer diol reaction products, based on the total weight of the pigmented aqueous basecoat material, is from 0.1 to 30 wt %.

12. The method of claim 1, wherein the pigmented aqueous basecoat material further comprises a polyurethane resin.

13. An automotive body or automotive component coated by a multiple-coat paint system according to the method of claim 1.

14. The method of claim 1, wherein the dimer diol is prepared by (ii) oligomerization of unsaturated fatty alcohols having 12 to 22 carbon atoms.

Description

EXAMPLES

(1) The dimer fatty acid used contains less than 1.5 wt % of trimeric molecules, 98 wt % of dimeric molecules, and less then 0.3 wt % of fatty acid (monomer), and is prepared on the basis of linolenic, linoleic, and oleic acid.

(2) Polyester 1 (P1):

(3) Prepared as per example D, column 16, lines 37 to 59 of DE 4009858 A. The corresponding polyester dispersion has a solids content of 60 wt %, the solvent used being butyl glycol instead of butanol.

(4) Inventive Dimer Fatty Acid/Dimer Diol Reaction Product 1 (DD1)

(5) In a 4 l stainless steel reactor equipped with anchor stirrer, thermometer, condenser, thermometer for overhead temperature measurement, and water separator, 1100 g of dimer diol (Pripol 2033 from Croda) having a hydroxyl number of 204 mg KOH/g, 579.3 g of dimer fatty acid (1 mol) (Pripol 1012, from Croda) and 70.0 g of cyclohexane were heated to 100 C. in the presence of 1.3 g of di-n-butyltin oxide (Axion CS 2455, from Chemtura). Heating was continued slowly until the onset of the condensation. Heating was then continued in steps to 220 C., with a maximum overhead temperature of 85 C. The progress of the reaction was monitored via determination of the acid number. When an acid number of 0.3 mg KOH/g was reached, any cyclohexane still present was removed by vacuum distillation. Cooling to room temperature gave a viscous resin.

(6) Gas chromatography found a cyclohexane content of less than 0.1%.

(7) Amount of condensate (water): 34.9 g

(8) Acid number: 0.1 mg KOH/g

(9) Solids content (60 min at 130 C.): 95.6%

(10) Solids content (GC): 100.0%

(11) M.sub.n (number-average molar mass (vapor pressure osmosis)): 1640 g/mol

(12) Viscosity (resin-xylene=2:1): 150.1 mPas, (measured at 23 C. using a rotational viscometer from Brookfield, CAP 2000+: spindle 3, shear rate: 13. 333 s.sup.1)

(13) Inventive Dimer Fatty Acid/Dimer Diol Reaction Product 2 (DD2)

(14) Analogously to the synthesis of the dimer fatty acid/dimer diol reaction product 1 (DD1), 1100 g of dimer diol. (Pripol 2033, from Croda) having a hydroxyl number of 204 mg KOH/g, 578.0 g of hydrogenated dimer fatty acid (1 mol) (Pripol 1009, from Croda) having an acid number of 194.1 mg KOH/g were esterified in the presence of 1.3 g of di-n-butyltin oxide (Axion CS 2455, from Chemtura), 70.0 g of cyclohexane having been used in turn as entraining agent.

(15) After distillation under vacuum of any cyclohexane still present, cooling to room temperature gave a viscous resin.

(16) Gas chromatography found a cyclohexane content of less than 0.1%.

(17) Amount of condensate (water): 35.5 g

(18) Acid number: 0.2 mg KOH/g

(19) Solids content (60 min at 130 C.): 99.9%

(20) Solids content (GC): 100.0%

(21) M.sub.n (number-average molar mass (vapor pressure osmosis)): 1630 g/mol

(22) Viscosity (resin:xylene=2:1): 182.2 mPas, (measured at 23 C. with a rotational viscometer from Brookfield, CAP 2000+, spindle 3, shear rate: 13 333 s.sup.1)

(23) Examples of Paint Formulations

(24) 1. Preparation of a Silver Waterborne Basecoat Material 1

(25) 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 mixture was then stirred for minutes and adjusted, using deionised 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 with a rotary viscometer (Rheomat RM 180 instrument from Mettler-Toledo) at 23 C.

(26) TABLE-US-00001 TABLE A Parts by Component weight Aqueous phase 3% strength NaMg 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 DSX 1550 (BASF), rheological agent P1 3.2 Tetramethyldecynediol (surfactant from 0.3 BASF) 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 Tetramethyldecynediol (surfactant from 1.6 BASF) 3% strength by weight aqueous Viscalex 3.9 HV 30 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
Waterborne Basecoat Material E1:

(27) To prepare the inventive waterborne basecoat material E1, a paint, was prepared in the same way as for the preparation of the waterborne basecoat material 1, using DD1 instead of polyester P1 both in the aqueous phase and in the organic phase. DD1 of the organic phase was first dissolved in a third of the amount of butyl glycol present in the organic phase. Additionally 0.984 part, by weight of butyl glycol was added to the organic phase to balance out the solvent content of the organic phase. DD1 of the aqueous phase was dissolved in 0.64 part by weight of butyl glycol, thereby also balancing out the solvent content of the aqueous phase.

(28) Waterborne Basecoat Material E2:

(29) To prepare the inventive waterborne basecoat material E2, a paint was prepared, in the same way as for the preparation of the waterborne basecoat material 1,using DD2 instead of polyester PI both in the aqueous phase and in the organic phase. DD2 was first dissolved in a third of the amount of butyl glycol present in the organic phase. Additionally 0.984 part by weight of butyl glycol was added to balance cut the solvent content of the organic phase, DD2 of the aqueous phase was dissolved in 0.64 part by weight of butyl glycol, thereby also balancing out the solvent content of the aqueous phase,

(30) TABLE-US-00002 TABLE 1 Compositions of waterborne basecoat materials 1 and E1 to E2 WBM [wt %] polymer solids 1 4.92 P1 E1 4.92 DD1 E2 4.92 DD2

(31) The weight percentage figures in table 1 are based on the overall weight of the waterborne basecoat material.

(32) Comparison Between Waterborne Basecoat Materials 1 and E1 to E2

(33) To determine the stability with respect to the occurrence of blisters and swelling after condensation-water storage, the multicoat paint systems were produced in accordance with the following general protocol:

(34) A steel panel coated with a standard cathodic electrocoat (Cathoguard 800 from BASF Coatings GmbH) and with dimensions of 1020 cm was coated with a standard surfacer (ALG 670173surfacer, 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.

(35) 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.

(36) 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:.

(37) 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.

(38) 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.

(39) The designation m0g0, accordingly, denotes a paint system which is blister-free after condensation-water storage, and represents a satisfactory result in terms of blistering.

(40) TABLE-US-00003 TABLE 2 Blistering and swelling of waterborne basecoat materials 1 and E1 to E2 WBM Blistering Swelling Assessment 1 m5g1 none unsat E1 m0g0 none sat E2 m0g0 none sat Key: m= number of blisters g= size of blisters sat = satisfactory result unsat = unsatisfactory result

(41) The results confirm that when the polyesters of the invention are used there are no longer any blisters after condensation-water storage and there are no longer any visible instances of swelling.

(42) 2. Preparation of a Silver Waterborne Basecoat Material 2

(43) 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 mixture 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 with a rotary viscometer (Rheomat RM 180 instrument from Mettler-Toledo) at 23 C.

(44) TABLE-US-00004 TABLE B Parts by Component weight Aqueous phase 3% strength NaMg 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 DSX 1550 (BASF), rheological agent P1 13.3 Tetramethyldecynediol (surfactant from 0.3 BASF) 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 Tetramethyldecynediol (surfactant from 1.6 BASF) 3% strength by weight aqueous Viscalex 3.9 HV 30 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
Waterborne Basecoat Material E3:

(45) To prepare the inventive waterborne basecoat material E4, a paint was prepared in the same way as for the preparation of the waterborne basecoat material 2, using DD1 instead of polyester P1 both in the aqueous phase and in the organic phase, DD1 of the organic phase was first dissolved in a third of the amount of butyl glycol present in the organic phase. Additionally 1 part, by weight of butyl glycol was added to the organic phase to balance out the solvent constituent, DD1 of the aqueous phase was dissolved in 2.66 parts by weight of butyl glycol, thereby also balancing out the solvent content of the aqueous phase.

(46) Waterborne Basecoat Material E4:

(47) To prepare the inventive waterborne basecoat material E5, a paint was prepared in the same way as for the preparation of the waterborne basecoat material 2, using DD2 instead of polyester P1 both in the aqueous phase and in the organic phase. DD2 of the organic phase was first dissolved in a third of the amount of butyl glycol present in the organic phase. Additionally 1 part by weight of butyl glycol was added to the organic phase to balance out the solvent constituent, DD2 of the aqueous phase was dissolved in 2.66 parts by weight of butyl glycol, thereby also balancing out the solvent content of the aqueous phase.

(48) TABLE-US-00005 TABLE 3 Compositions of waterborne basecoat materials 2 and E3 to E4 WBM [wt %] polymer solids 2 10.98 P1 E3 10.98 DD1 E4 10.98 DD2

(49) The weight percentage figures in table 3 are based on the overall weight of the waterborne basecoat material.

(50) Comparison Between Waterborne Basecoat Materials 2 and E3 to E4

(51) To determine the stability with respect to the occurrence of blisters and swelling after condensation-water storage, the multicoat paint systems were produced in accordance with the following general protocol:

(52) A steel panel coated with a standard cathodic electrocoat (Cathoguard 800 from BASF Coatings GmbH) and with dimensions of 1020 cm was coated with a standard surfacer (ALG 670173surfacer, 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.

(53) The respective waterborne basecoat material from table 3 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.

(54) This original finish is abraded with abrasive paper and then the respective waterborne baseeoat material, from table 3 is applied pneumatically to this abraded original finish. The resulting waterborne baseeoat 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 baseeoat film. The resulting clearcoat film was flashed at room temperature for 20 minutes. The waterborne baseeoat film and the clearcoat film were then cured in a forced-air oven at 80 C. for 30 minutes.

(55) 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.

(56) 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, accordingly, denotes a paint system which is blister-free after condensation-water storage, and represents a satisfactory result in terms of blistering.

(57) TABLE-US-00006 TABLE 4 Blistering and swelling of waterborne basecoat materials 3 and E3 to E4 WBM Blistering Swelling Assessment 2 m5g4 none unsat E3 m0g0 none sat E4 m0g0 none sat Key: m= number of blisters g= size of blisters sat = satisfactory result unsat = unsatisfactory result

(58) The results confirm that when the polyesters of the invention are used there are no longer any blisters after condensation-water storage and there are no longer any visible instances of swelling.