COATING COMPOSITIONS COMPRISING A POLYSULFIDE CORROSION INHIBITOR

Abstract

The present disclosure is directed to a coating composition comprising a film-forming binder, and a corrosion inhibitor comprising a polysulfide corrosion inhibitor, wherein the polysulfide corrosion inhibitor has a passive window value measured as a solution over a substrate greater than the passive window value of a solution without the corrosion inhibitor tested over the same substrate, as measured according to the PASSIVE WINDOW TEST METHOD, and the poly sulfide corrosion inhibitor has a polarization resistance (Rp) measured as a solution over a substrate greater than the polarization resistance (Rp) of a solution without the corrosion inhibitor tested over the same substrate, as measured according to the LINEAR POLARIZATION RESISTANCE TEST METHOD.

Claims

1. A coating composition comprising: a film-forming binder, and a corrosion inhibitor comprising a polysulfide corrosion inhibitor, wherein the polysulfide corrosion inhibitor has a passive window value measured as a solution over a substrate greater than the passive window value of a solution without the corrosion inhibitor tested over the same substrate, as measured according to the PASSIVE WINDOW TEST METHOD, and the polysulfide corrosion inhibitor has a polarization resistance (Rp) measured as a solution over a substrate greater than the polarization resistance (Rp) of a solution without the corrosion inhibitor tested over the same substrate, as measured according to the LINEAR POLARIZATION RESISTANCE TEST METHOD.

2. The coating composition of claim 1, wherein the polysulfide corrosion inhibitor has a passive window over a 2024-T3 aluminum alloy substrate of greater than 28 mV, as measured according to the PASSIVE WINDOW TEST METHOD.

3. The coating composition of any of the preceding Claims claim 1, wherein the polysulfide corrosion inhibitor has a polarization resistance (Rp) over a 2024-T3 aluminum alloy substrate of greater than 28?6 k?*cm.sup.2, as measured according to the LINEAR POLARIZATION RESISTANCE TEST METHOD.

4. The coating composition of claim 1, wherein the polysulfide corrosion inhibitor comprises the structure (I): ##STR00018## wherein each X.sub.1 independently comprises S, N, or CH; each R.sub.1 independently comprises an alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, or cycloalkyl group, or together with X.sub.1 forms a heteroaryl or heterocycle structure; X comprises C when X.sub.1 is N or N when X.sub.1 is S or CH; each R.sub.2 independently comprises hydrogen or an alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, or cycloalkyl group when X is C or N and R.sub.2 is not present when X is S; and n is an integer from 1 to 10.

5. The coating composition of claim 1, wherein the polysulfide corrosion inhibitor comprises a disulfide corrosion inhibitor comprising the structure (II): ##STR00019## wherein each X.sub.1 independently comprises S, N, or CH; each R.sub.1 independently comprises an alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, or cycloalkyl group, or together with X.sub.1 forms a heteroaryl or heterocycle structure; X comprises C when X.sub.1 is N or N when X.sub.1 is S or CH; and each R.sub.2 independently comprises hydrogen or an alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, or cycloalkyl group when X is C or N and R.sub.2 is not present when X is S.

6. The coating composition of claim 1, wherein the polysulfide corrosion inhibitor comprises a disulfide corrosion inhibitor comprising the structure (III): ##STR00020## wherein each R.sub.1 independently comprises an alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, or cycloalkyl group; each R.sub.2 independently comprises hydrogen or an alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, or cycloalkyl group.

7. The coating composition of claim 6, wherein each R.sub.1 and R.sub.2 independently comprise an alkyl group having no more than six carbon atoms.

8. The coating composition of claim 1, wherein the polysulfide corrosion inhibitor comprises a disulfide corrosion inhibitor comprising the structure (IV): ##STR00021##

9. The coating composition of claim 1, wherein the polysulfide corrosion inhibitor comprises a disulfide corrosion inhibitor comprising the structure (V): ##STR00022##

10. The coating composition of claim 1, wherein the polysulfide corrosion inhibitor comprises a disulfide corrosion inhibitor comprising the structure (VI): ##STR00023## wherein R.sub.1 and R.sub.2 each independently comprise hydrogen or an alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, or cycloalkyl group.

11. The coating composition of claim 1, wherein the polysulfide corrosion inhibitor comprises a disulfide corrosion inhibitor comprising the structure (VII): ##STR00024## wherein R.sub.3 and R.sub.4 each independently comprise alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, and cycloalkyl, wherein particularly said alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, and cycloalkyl are each independently substituted or unsubstituted with one or more suitable substituents.

12. (canceled)

13. A coating composition comprising: a film-forming binder, and a corrosion inhibitor comprising a polysulfide corrosion inhibitor comprising the structure (I): ##STR00025## wherein each X.sub.1 independently comprises S, N, or CH; each R.sub.1 independently comprises an alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, or cycloalkyl group, or together with X.sub.1 forms a heteroaryl or heterocycle structure; X comprises C when X.sub.1 is N or N when X.sub.1 is S or CH; each R.sub.2 independently comprises hydrogen or an alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocycle, or cycloalkyl group when X is C or N and R.sub.2 is not present when X is S; and n is an integer from 1 to 10.

14-21. (cancelled)

22. The coating composition of claim 1, wherein the wherein the polysulfide corrosion inhibitor comprises only one polysulfide linkage.

23. The coating composition of claim 1, wherein the wherein the polysulfide corrosion inhibitor is a non-cyclic compound.

24. (canceled)

25. The coating composition of claim 1, wherein the coating composition is an electrodepositable coating composition.

26-31. (canceled)

32. The coating composition of claim 1, wherein the film-forming binder component comprises (a) an organic resin component; and (b) a curing agent component, and wherein the organic resin component comprises a polymer having epoxide functional groups, and the curing agent component comprises a crosslinker comprising amino functional groups, or wherein the organic resin component comprises a polymer having hydroxyl functional groups, and the curing agent component comprises a crosslinker comprising isocyanato functional groups.

33-39. (canceled)

40. The coating composition of claim 1, wherein the corrosion inhibitor is free of functional groups that are reactive with functional groups of the film-forming binder.

41-51. (canceled)

52. A metal substrate at least partially coated with a coating deposited from the coating composition of claim 1.

53-58. (canceled)

59. A multilayer coated metal substrate comprising: (a) a metal substrate; (b) a first coating layer present on at least a portion of said metal substrate; and (c) a second coating layer present on at least a portion of the first coating, wherein the first coating layer, the second coating layer or both layers comprise a coating deposited from the coating composition of claim 1.

60-69. (canceled)

70. A method for coating a substrate comprising applying the coating composition of claim 1 to at least a portion of the substrate.

71-73. (canceled)

Description

EXAMPLES

Solution Electrochemistry

[0234] Potential polysulfide corrosion inhibitors were tested using solution electrochemistry techniques in order to determine whether they might provide corrosion protection to an underlying substrate. The testing was performed as follows: Aluminum alloys of 2024-T3 were used for all solution electrochemistry experiments. The panels were first cleaned using a methyl ethyl ketone (MEK) wipe. Panels were then immersed in BONDERITE? C-AK 298 ALKALINE CLEANER (previously known as Ridoline? 298 and commercially available from Henkel) for 2 minutes at 130? F. followed by a 1 minute immersion in tap water and a spray rinse of tap water. The panels were then immersed in a deoxidizing bath consisting of BONDERITE? C-IC DEOXDZR.sub.6MU AERO/BONDERITE? C-IC DEOXDZR 16R AERO (previously known as Turco? Deoxidizer 6 Makeup and Turco? Deoxidizer 16 Replenisher, both commercially available from Henkel) for 230 at ambient conditions; followed by a 1 minute immersion in tap water and finally a spray rinse of deionized water. Each sample was evaluated for Linear Polarization Resistance and Window of Passivity.

[0235] Linear Polarization Resistance: Individual linear polarization scans were conducted in an aqueous solution of 50 mM NaCl with a concentration of inhibiting compound, ranging from 0.25 to 1 mM. Scans were carried out after a 10 minute period at the open circuit potential, followed by a ramp from ?0.02 to 0.02 V.sub.OCP at 1 mV/s using a standard calomel reference electrode and a platinum counter electrode. The above prepared aluminum alloys of 2024-T3 sample were used as the working electrode for each replicate test with an exposed working electrode test area of 2.8 cm.sup.2 exposed to a solution for each replicate test. At least four scans were performed for each inhibiting compound. The polarization resistance (Rp) is taken as the slope of the potential vs. current density plot. Scans in neat 50 mM NaCl solution were taken as the control, and exhibited an average Rp value of 28?6 k?*cm.sup.2. Inhibiting compounds that gave Rp values higher than 28 k?*cm.sup.2 were considered to have a slower corrosion rate than the control. This test is referred to herein as the LINEAR POLARIZATION RESISTANCE TEST METHOD.

[0236] Window of Passivity: Individual anodic polarization scans were conducted in aqueous solution of 50 mM NaCl with a concentration of inhibiting compound, ranging from 0.25 to 1 mM. Scans were carried out after a 10 minute period at the open circuit potential, followed by a ramp from ?0.02 to 0.3 V.sub.OCP at 1 mV/s using a standard calomel reference electrode and a platinum counter electrode. The above prepared aluminum alloys of 2024-T3 sample were used as the working electrode for each replicate test with an exposed working electrode test area of 2.8 cm.sup.2 exposed to a solution for each replicate test. At least duplicate scans were performed for each inhibiting compound. The window of passivity is taken as the difference between the breakdown potential and the open circuit potential. Scans in neat 50 mM NaCl aqueous solution were taken as the control and exhibited an average passive window of 28 mV. Inhibiting compounds resulting in passive windows higher than 28 mV were considered to provide better corrosion protection than the control. This test is referred to herein as the PASSIVE WINDOW TEST METHOD.

[0237] Corrosion inhibitors solutions that tested with a polarization resistance (Rp) higher than 28 k?*cm.sup.2 and a passive window greater than 28 mV were expected to provide corrosion resistance over 2024-T3 aluminum substrates. The following corrosion inhibitors satisfied both conditions:

TABLE-US-00001 Linear Passive polarization Window resistance Compound (mv) (k?*cm.sup.2) NaCl (control) 28 ? 0 28 ? 6 2,2-Dipyridyl Disulfide 169.4 ? 9.2 68 ? 5 3-Dimethylamino-1,2,4-dithiazole-5-thione 125 ? 80 350 ? 84 Dipentamethylenethiuram hexasulfide, 61 ? 11 52 ? 17 DPTT, SULFADS PWDR Ethyl Tuads? 181 ? 13 52 ? 19 Butyl Tuads 79 ? 8 80 ? 12 Isobutyl Tuads 35 ? 9 40 ? 10 5,5-dinitro-2,2,dithiosdipyridine 57 ? 8 93 ? 47 Tetramethythruam disulfide 128 ? 30 411 ? 268 Tetrabenzylthiruam disulfide 42 ? 3 42 ? 10 5,5-dithiobis(1-phenyl-tetrazole) 47 ? 1 167 ? 55

[0238] The following corrosion inhibitors failed to satisfy one or both of the tests:

TABLE-US-00002 Passive Linear polarization Window resistance Compound (mv) (k?*cm.sup.2) NaCl (control) 28 ? 0 28 ? 6 Vanax A; 4,4-dithiodimopholine; 441 ? 23 26 ? 6 Di(morpholin-4-yl)disulfide; Ekaland DTDM PD 4,4-Dipyridyl Disulfide 0 76 ? 60

TABLE-US-00003 TABLE 1 provides a description of materials used in preparation of the examples. Component Description Supplier Ancamide? 2569 Polyamide curing agent Evonik Ancamide? 2050 Polyamide curing agent Evonik Ancamine? 2432 Polyamine curing agent Evonik Ancamine? K54 Catalyst Evonik Ti-Pure? R-706-11 Titanium Dioxide DuPont Epon? 828 Bisphenol A/epichlorohydrin resin Momentive Epon? 8111 Modified Epoxy resin Momentive Silquest? A187 Epoxy-silane Momentive Nano Magnesium Oxide MgO: 20 nm ave. particle size, Nano Structured and 50 m.sup.2/g surface area Amorphous Materials Maglite? Y MgO: 10 micron ave. particle size, Hallstar 55 m.sup.2/g surface area Magchem? 10-325 MgO: 10 micron ave. particle size, Martin Marietta 3 m.sup.2/g surface area Magnesia Specialties Acematt? OK-412 Silicon Dioxide Evonik Milling media Part #74582 minimum 85% Al.sub.2O.sub.3 (16 Coors Tek to 20 mesh) ACRS2100 Aerocron Feed Material PPG Industries ACPP2120 Aerocron Feed Material PPG Industries BONDERITE? C-AK 298 Alkaline Immersion Cleaner Henkel BONDERITE? C-IC Deoxidizer Henkel DEOXDZR 6MU AERO/ BONDERITE? C-IC DEOXDZR 16R AERO Ethyl Tuads? Tetraethyl thiuram disulphide Vanderbilt Chemicals QA-4326 2,2-Dipyridyl Disulfide Combi-Blocks, Inc CA9311 Polyurethane Topcoat Base Component PPG Industries CA8351 Polyurethane Topcoat Base Component PPG Industries CA9300B Polyurethane Topcoat Activator PPG Industries Component CA8310B Polyurethane Topcoat Activator PPG Industries Component

Spray Primer Coating Examples 1-6

[0239]

TABLE-US-00004 TABLE 2A Primer Only Coating Examples Comp Comp Ex 1 Ex 2 Ex 3 Ex 4 Ex 5 Ex 6 Material g g g g g g Component A Ancamide 2569 8.0 8.0 8.0 11.3 11.3 11.3 Ancamine 2432 5.3 5.3 5.3 7.5 7.5 7.5 Ancamine K-54 0.6 0.6 0.6 0.6 0.6 0.6 N-butyl alcohol 13.6 13.6 13.6 13.2 13.2 13.2 Butyl Acetate 15.2 15.2 15.2 14.9 14.9 14.9 Xylene 1.3 1.3 1.3 1.2 1.2 1.2 Ti-Pure R-706-11 17.4 17.4 17.4 21.2 21.2 21.2 Nano-magnesium 6.5 6.5 6.5 0 0 0 oxide Acematt OK-412 0 0 0 2.1 2.1 2.1 Total 67.9 67.9 67.9 72.0 72.0 72.0 Component B Epon 828 26.2 26.2 26.2 23.6 23.6 23.6 Epon 8111 4.2 4.2 4.2 3.8 3.8 3.8 Xylene 0.7 0.7 0.7 0.7 0.7 0.7 Butyl Acetate 14.3 14.3 14.3 13.9 13.9 13.9 Methyl Acetate 7.9 7.9 7.9 7.7 7.7 7.7 Maglite Y 13.1 13.1 13.1 0 0 0 MagChem 10-325 6.5 6.5 6.5 0 0 0 Ti-Pure R-706-11 0 0 0 19.1 19.1 19.1 DPDS 0 8.7 0 0 8.5 0 Ethyl Tuads 0 0 8.7 0 0 8.5 Silquest A-187 0.7 0.7 0.7 0.7 0.7 0.7 Total 73.6 82.3 82.3 69.5 78.0 78.0 Total Blended Weight 141.5 150.2 150.2 141.5 150.0 150.0

TABLE-US-00005 TABLE 2B Primer Only Coating Examples Comp Comp Ex 1B Ex 2B Ex 3B Ex 4B Ex 5B Ex 6B Material g g g g g g Component A Ancamide 2050 11.5 11.5 11.5 11.5 11.5 11.5 Ancamine 2432 7.7 7.7 7.7 7.7 7.7 7.7 Ancamine K-54 0.6 0.6 0.6 0.6 0.6 0.6 N-butyl alcohol 13.5 13.5 13.5 13.5 13.5 13.5 Butyl Acetate 15.1 15.1 15.1 15.1 15.1 15.1 Xylene 1.3 1.3 1.3 1.3 1.3 1.3 Ti-Pure R-706-11 16.4 16.4 16.4 20.5 20.5 20.5 Acematt OK-412 0 0 0 2.0 2.0 2.0 Nano-magnesium 6.1 6.1 6.1 0 0 0 oxide Total 72.2 72.2 72.2 72.2 72.2 72.2 Component B Epon 828 24.1 24.1 24.1 24.1 24.1 24.1 Epon 8111 3.9 3.9 3.9 3.9 3.9 3.9 Butyl Acetate 14.2 14.2 14.2 14.2 14.2 14.2 Xylene 0.7 0.7 0.7 0.7 0.7 0.7 Methyl Acetate 7.9 7.9 7.9 7.9 7.9 7.9 Maglite Y 12.3 12.3 12.3 0 0 0 MagChem 10-325 6.1 6.1 6.1 0 0 0 Ti-Pure R-706-11 0 0 0 18.4 18.4 18.4 DPDS 0 8.2 0 0 8.2 0 Ethyl Tuads 0 0 8.2 0 0 8.2 Silquest A-187 0.7 0.7 0.7 0.7 0.7 0.7 Total 69.9 78.1 78.1 69.9 78.1 78.1 Total Blended 142.1 150.3 150.3 142.1 150.3 150.3 Weight

[0240] Coating Examples 1A through 6A in Table 2A and Examples 1B through 6B in Table 2B were prepared as follows: For Component A of each example, all materials were weighed and placed into glass jars. Dispersing media was then added to each jar at a level equal to approximately one-half the total weight of the component materials. The jars were sealed with lids and then placed on a Lau Dispersing Unit with a dispersion time of 3 hours. For Component B of each example, all materials with the exception of the Silquest A-187 were weighed and placed into glass jars. Dispersing media was then added to each jar at a level equal to approximately one-half the total weight of the component materials. The jars were sealed with lids and then placed on a Lau Dispersing Unit with a dispersion time of 3 hours. The Silquest A-187 was added to the Component B mixtures after the pigment dispersion process was completed. Each final Component B mixture was then thoroughly mixed. Approximately 30 minutes prior to application of the coating, Component A and B were combined together, thoroughly mixed, and the dispersing media was filtered from the solution.

[0241] The coatings of Examples 1A through 6A and Examples 1B through 6B were spray applied onto 2024T3 bare and clad aluminum alloy substrate panels to a dry film thickness of between 1.0 to 1.5 mils using an air atomized spray gun. Prior to coating application, the panels were first cleaned using a methyl ethyl ketone (MEK) wipe. Panels were then immersed in BONDERITE? C-AK 298 ALKALINE CLEANER (previously known as Ridoline? 298 and commercially available from Henkel) for 2 minutes at 130? F. followed by a 1 minute immersion in tap water and a spray rinse of tap water. The panels were then immersed in a deoxidizing bath consisting of BONDERITE? C-IC DEOXDZR.sub.6MU AERO/BONDERITE? C-IC DEOXDZR 16R AERO (previously known as Turco? Deoxidizer 6 Makeup and Turco? Deoxidizer 16 Replenisher, both commercially available from Henkel) for 230 at ambient conditions; followed by a 1 minute immersion in tap water and finally a spray rinse of deionized water. The panels were allowed to dry under ambient conditions for at least 2 hours prior to spray application.

[0242] The fully coated test panels coated with coating Examples 1A through 6A and Examples 1B through 6B were allowed to age under ambient conditions for a minimum of 7 days, after which the panels were inscribed with a 10 cm by 10 cm X that was scribed into the panel surface to a sufficient depth to penetrate any surface coating and to expose the underlying metal. The scribed coated test panels were then placed into a 5% sodium chloride neutral salt spray cabinet according to ASTM B117 (exception: pH & salt concentration checked weekly as opposed to daily).

[0243] The ratings shown in TABLE 3A were at 528 hours of exposure for Examples 1A, 2A, and 3A and 504 hours for Examples 4A, 5A, and 6A.

[0244] The ratings shown in TABLE 3B were at 1848 hours of exposure for Examples 1B through 6B.

[0245] The panels were rated according to the following scale:

[0246] Scribe Corrosion: Lower rating number is better; Rating is 0 to 100 and number represents percent of scribe area showing visible corrosion. The value is the average of two replicates.

[0247] Scribe Shine: Lower rating number is better; Rating is 0-100 and number represents percent of scribe which is dark/tarnished scribe. The value is the average of two replicates.

TABLE-US-00006 TABLE 3A Corrosion Test Results for Examples 1A-6A Al 2024-T3 Bare Al 2024-T3 Clad Scribe Scribe Scribe Scribe Example # Description Corr. Shine Corr. Shine Comp Ex 1A MgO Primer Control 10 75 10 75 Ex 2A MgO Primer with DPDS 5 65 5 55 Ex 3A MgO Primer with Ethyl Tuads? 10 75 15 75 Comp Ex 4A Non-MgO Primer Control 25 90 30 85 Ex 5A Non-MgO Primer with DPDS 5 70 10 75 Ex 6A Non-MgO Primer with Ethyl Tuads? 10 80 10 80

[0248] The corrosion data in TABLE 3 clearly shows that the DPDS Coating Examples 2 and 5 when compared to Comparative Examples 1 and 4, respectively, provide measurably enhanced corrosion protection for both the Al 2024-T3 Bare and A1 2024-T3 Clad. The Ethyl Tuads? Coating Example 6 when compared to Comparative Example 4 provides measurably enhanced corrosion protection for both A1 2024-T3 Bare and A1 2024-T3 Clad. No improvement or degradation of corrosion protection was witnessed when comparing Coating Example 3 to Comparative Example 1 with Ethyl Tuads? and MgO. Evidence of the enhanced corrosion protection is observed in the presence of lower or no amounts of corrosion in the scribe and the more shiny nature of the scribes.

TABLE-US-00007 TABLE 3B Corrosion Test Results for Examples 1B-6B Al 2024-T3 Bare Al 2024-T3 Clad Scribe Scribe Scribe Scribe Example # Description Corr. Shine Corr. Shine Comp Ex 1B MgO Primer Control 25 80 25 60 Ex 2B MgO Primer with DPDS 5 50 5 50 Ex 3B MgO Primer with Ethyl Tuads? 10 55 5 55 Comp Ex 4B Non-MgO Primer Control 20 95 40 95 Ex 5B Non-MgO Primer with DPDS 15 85 15 90 Ex 6B Non-MgO Primer with Ethyl Tuads? 15 90 20 90

[0249] The corrosion data in TABLE 3B clearly shows that the DPDS Coating Examples 2B and 5B and Ethyl Tuads? Coating Examples 3B and 6B when compared to Comparative Examples 1B and 4B, respectively, provide measurably enhanced corrosion protection for both the A1 2024-T3 Bare and A1 2024-T3 Clad substrates. Evidence of the enhanced corrosion protection is observed in the presence of lower or no amounts of corrosion in the scribe and the more shiny nature of the scribes.

Spray Primer Coating Composition and Topcoat Examples 7-12

[0250]

TABLE-US-00008 TABLE 4A Spray Primer and Topcoat Coating Examples Comp Comp Ex Ex Ex Ex Ex Ex Material 7A 8A 9A 10A 11A 12A FIRST COATING Component A Ancamide 2569 8.5 8.5 8.5 8.5 8.5 8.5 Ancamine 2432 5.6 5.6 5.6 5.6 5.6 5.6 Ancamine K-54 0.6 0.6 0.6 0.6 0.6 0.6 N-butyl alcohol 14.4 14.4 14.4 14.4 14.4 14.4 Butyl Acetate 16.2 16.2 16.2 16.2 16.2 16.2 Xylene 1.4 1.4 1.4 1.4 1.4 1.4 Ti-Pure R-706-11 25.4 25.4 25.4 18.5 18.5 18.5 Nano-magnesium 0 0 0 6.9 6.9 6.9 oxide Total 72.1 72.1 72.1 72.1 72.1 72.1 Component B Epon 828 27.8 27.8 27.8 27.8 27.8 27.8 Epon 8111 4.4 4.4 4.4 4.4 4.4 4.4 Xylene 0.7 0.7 0.7 0.7 0.7 0.7 Butyl Acetate 15.1 15.1 15.1 15.1 15.1 15.1 Methyl Acetate 8.4 8.4 8.4 8.4 8.4 8.4 Maglite Y 0 0 0 13.9 13.9 13.9 MagChem 10-325 0 0 0 6.9 6.9 6.9 Ti-Pure R-706-11 20.8 20.8 20.8 0 0 0 Silquest A-187 0.8 0.8 0.8 0.8 0.8 0.8 Total 78.0 78.0 78.0 78.0 78.0 78.0 Total Blended 150.1 150.1 150.1 150.1 150.1 150.1 Weight SECOND COATING Component A CA8351 118.5 118.5 118.5 118.5 118.5 118.5 DPDS 0 7.6 0 0 7.6 0 Ethyl Tuads 0 0 7.6 0 0 7.6 Butyl Acetate 0 4.2 4.2 0 4.2 4.2 Component B CA8310B 27.2 27.2 27.2 27.2 27.2 27.2 Component C Butyl Acetate 0 2.6 2.5 0 2.6 2.5 Total 145.7 160.1 160.0 145.7 160.1 160.0

TABLE-US-00009 TABLE 4B Spray Primer and Topcoat Coating Examples Comp Comp Ex 7B Ex 8B Ex 10B Ex 11B Material g g g g FIRST COATING Component A Ancamide 2050 11.5 11.5 11.5 11.5 Ancamine 2432 7.7 7.7 7.7 7.7 Ancamine K-54 0.6 0.6 0.6 0.6 N-butyl alcohol 13.5 13.5 13.5 13.5 Butyl Acetate 15.1 15.1 15.1 15.1 Xylene 1.3 1.3 1.3 1.3 Ti-Pure R-706-11 20.5 20.5 16.4 16.4 Acematt OK-412 2.0 2.0 0 0 Nano-magnesium oxide 0 0 6.1 6.1 Total 72.1 72.1 72.2 72.2 Component B Epon 828 24.1 24.1 24.1 24.1 Epon 8111 3.9 3.9 3.9 3.9 Butyl Acetate 14.2 14.2 14.2 14.2 Xylene 0.7 0.7 0.7 0.7 Methyl Acetate 7.9 7.9 7.9 7.9 Maglite Y 0 0 12.3 12.3 MagChem 10-325 0 0 6.1 6.1 Ti-Pure R-706-11 18.4 18.4 0 0 Silquest A-187 0.7 0.7 0.7 0.7 Total 69.9 69.9 69.9 69.9 Total Blended Weight 142.1 142.1 142.1 142.1 SECOND COATING Component A CA9311 (F36173) Base 100.0 100.0 100.0 100.0 DPDS 0 10.5 0 10.5 MAK (methyl amyl ketone) 0 10.5 0 10.5 Component B CA9300B Activator 30.5 30.5 30.5 30.5 Total 130.5 151.5 130.5 151.5

[0251] Coating Examples 7A through 12A and 7B, 8B, 10B, and 11B were prepared as follows:

[0252] First Coating: For Component A of each example, all materials were weighed and placed into glass jars. Dispersing media was then added to each jar at a level equal to approximately one-half the total weight of the component materials. The jars were sealed with lids and then placed on a Lau Dispersing Unit with a dispersion time of 3 hours. For Component B of each example, all materials with the exception of the Silquest A-187 were weighed and placed into glass jars. Dispersing media was then added to each jar at a level equal to approximately one-half the total weight of the component materials. The jars were sealed with lids and then placed on a Lau Dispersing Unit with a dispersion time of 3 hours. The Silquest A-187 was added to the Component B mixtures after the pigment dispersion process was completed. Each final Component B mixture was then thoroughly mixed. Approximately 30 minutes prior to application of the coating, Component A and B were combined together, thoroughly mixed, and the dispersing media was filtered from the solution.

[0253] The coatings of Examples 7A through 12A and Examples 7B, 8B, 10B, and 11B were spray applied onto 2024T3 bare and clad aluminum alloy substrate panels to a dry film thickness of between 0.8 to 1.2 mils using an air atomized spray gun. Prior to coating application, the panels were first cleaned using a methyl ethyl ketone (MEK) wipe. Panels were then immersed in BONDERITE? C-AK 298 ALKALINE CLEANER (previously known as Ridoline? 298 and commercially available from Henkel) for 2 minutes at 130? F. followed by a 1 minute immersion in tap water and a spray rinse of tap water. The panels were then immersed in a deoxidizing bath consisting of BONDERITE? C-IC DEOXDZR.sub.6MU AERO/BONDERITE? C-IC DEOXDZR.sub.16R AERO (previously known as Turco? Deoxidizer 6 Makeup and Turco? Deoxidizer 16 Replenisher, both commercially available from Henkel) for 230 at ambient conditions; followed by a 1 minute immersion in tap water and finally a spray rinse of deionized water. The panels were allowed to dry under ambient conditions for at least 2 hours prior to spray application.

[0254] Following application of the First Coating for each Example, the coated panels were stored under ambient conditions for 12 to 24 hours before application of the Second Coating of each Example.

[0255] Second Coating of Examples 7A through 12A: For Component A of each Example 7A through 12A, all materials were weighed and placed into glass jars. Dispersing media was then added to each jar at a level equal to approximately one-half the total weight of the component materials. The jars were sealed with lids and then placed on a Lau Dispersing Unit with a dispersion time of 3 hours. Components B and C were mixed with Component A prior to application.

[0256] The Second Coatings of Examples 7A through 12A were spray applied over the First Coating to a dry film thickness between 1.4 to 1.7 mils using an air atomized spray gun.

[0257] Second Coating of Examples 7B, 8B, 10B, and 11B: For Component A of each example 7B, 8B, 10B, and 11B, all materials were weighed and placed into glass jars. Dispersing media was then added to each jar at a level equal to approximately one-half the total weight of the component materials. The jars were sealed with lids and then placed on a Lau Dispersing Unit with a dispersion time of 3 hours. Prior to application of the coating, Component A and B were combined together, thoroughly mixed, and the dispersing media was filtered from the solution.

[0258] The Second Coatings of Examples 7B, 8B, 10B, and 11B were spray applied over the First Coating to a dry film thickness between 1.8 to 2.6 mils using an air atomized spray gun.

[0259] Evaluation: The fully coated test panels coated with coating Examples 7 through 12 were allowed to age under ambient conditions for a minimum of 7 days, after which the panels were inscribed with a 10 cm by 10 cm X that was scribed into the panel surface to a sufficient depth to penetrate any surface coating and to expose the underlying metal. The scribed coated test panels were then placed into a 5% sodium chloride neutral salt spray cabinet according to ASTM B117 (exception: pH & salt concentration checked weekly as opposed to daily).

[0260] The ratings shown in TABLE 5A were at 456 hours of exposure for Examples 7A through 12A. The panels were rated according to the Scribe Corrosion and Scribe Shine ratings described above. The values were for the average of two replicates.

TABLE-US-00010 TABLE 5A Corrosion Test Results for Examples 7A through 12A Al 2024-T3 Bare Al 2024-T3 Clad Scribe Scribe Scribe Scribe Example # Description Corr. Shine Corr. Shine Comp Ex 7 Non-MgO Primer with Control Topcoat 25 95 25 95 Ex 8 Non-MgO Primer with DPDS Topcoat 5 60 5 40 Ex 9 Non-MgO Primer with Ethyl Tuads? Topcoat 25 90 10 85 Comp Ex 10 MgO Primer with Control Topcoat 25 90 15 75 Ex 11 MgO Primer with DPDS Topcoat 5 40 5 40 Ex 12 MgO Primer with Ethyl Tuads? Topcoat 5 70 5 70

[0261] The corrosion data in TABLE 5 clearly shows that the DPDS Coating Examples 8 and 11 when compared to Comparative Examples 7 and 10, respectively, provide measurably enhanced corrosion protection for both the A1 2024-T3 Bare and A1 2024-T3 Clad. The Ethyl Tuads? Coating Example 12 when compared to Comparative Example 10 provides measurably enhanced corrosion protection for both A1 2024-T3 Bare and A1 2024-T3 Clad. Slight improvement of corrosion protection was witnessed when comparing Coating Example 9 to Comparative Example 7 with Ethyl Tuads?. Evidence of the enhanced corrosion protection is observed in the presence of lower or no amounts of corrosion in the scribe and the more shiny nature of the scribes.

[0262] The ratings shown in TABLE 5B were at 624 hours of exposure for examples 7B, 8B, 10B, and 11B. The panels were rated according to the Scribe Corrosion and Scribe Shine ratings described above. The values were for the average of two replicates.

TABLE-US-00011 TABLE 5B Corrosion Test Results for Examples 7B, 8B, 10B, and 11B Al 2024-T3 Bare Al 2024-T3 Clad Scribe Scribe Scribe Scribe Example # Description Corr. Shine Corr. Shine Comp Ex 7B Non-MgO Primer with Control Topcoat 45 95 30 95 Ex 8B Non-MgO Primer with DPDS Topcoat 5 40 15 70 Comp Ex 10B MgO Primer with Control Topcoat 15 75 5 75 Ex 11B MgO Primer with DPDS Topcoat 5 45 5 40

[0263] The corrosion data in TABLE 5B clearly shows that the DPDS Coating Examples 8A and 11A when compared to Comparative Examples 7B and 10B, respectively, provide measurably enhanced corrosion protection for both the A1 2024-T3 Bare and A1 2024-T3 Clad substrates. Evidence of the enhanced corrosion protection is observed in the presence of lower or no amounts of corrosion in the scribe and the more shiny nature of the scribes.

Uninhibited Electrocoat Primer and Inhibited Topcoat Examples 13-15

[0264]

TABLE-US-00012 TABLE 6 Electrocoat Primer and Topcoat Coating Examples Comp Ex 13 Ex 14 Ex 15 Material g g g FIRST COATING - Electrocoat Primer Charge 1 ACRS2100 1390.7 1390.7 1390.7 Charge 2 ACPP2120 239.0 239.0 239.0 Charge 3 Distilled Water 1170.3 1170.3 1170.3 Total Blended Weight 2800.0 2800.0 2800.0 SECOND COATING Component A CA8351 118.5 118.5 118.5 DPDS 0 7.6 0 Ethyl Tuads 0 0 7.6 Butyl Acetate 0 4.2 4.2 Component B CA8310B 27.2 27.2 27.2 Component C Butyl Acetate 0 2.6 2.5 Total 145.7 160.1 160.0

[0265] First Coating: The electrodepositable coating compositions were prepared by the following procedure: Charge 1 was added to a 1 gallon plastic bucket and agitation was started. Charge 2 was added slowly over 5 minutes. Finally, Charge 3 was added over 5 minutes. The resulting mixture stirred for an additional 15 minutes. The paints were then ultrafiltered to remove 50% of the original mass of the bath which was replaced with additional deionized water to return it to the original starting weight.

[0266] The panels were first cleaned using an acetone wipe. Panels were then immersed in BONDERITE? C-AK 298 ALKALINE CLEANER (previously known as Ridoline? 298 and commercially available from Henkel) for 2 minutes at 130? F. followed by a 1 minute immersion in tap water and a spray rinse of tap water. The panels were then immersed in a deoxidizing bath consisting of BONDERITE? C-IC DEOXDZR.sub.6MU AERO/BONDERITE? C-IC DEOXDZR 16R AERO (previously known as Turco? Deoxidizer 6 Makeup and Turco? Deoxidizer 16 Replenisher, both commercially available from Henkel) for 230 at ambient conditions; followed by a 1 minute immersion in tap water and finally a spray rinse of deionized water. The panels were allowed to dry under ambient conditions for 1-2 hours prior to electrocoat application. The paints were electrodeposited onto the test panels using 0.3 amps for 90 seconds at a bath temperature of 75? F. using voltages between 100 and 200 volts. The coatings of Examples 13 through 15 were applied onto the 2024T3 bare and clad aluminum alloy substrate panels to a dry film thickness of between 0.6 to 0.9 mils and cured at 225 F for 30 minutes.

[0267] Second Coating: For Component A of each example 13 through 15, all materials were weighed and placed into glass jars. Dispersing media was then added to each jar at a level equal to approximately one-half the total weight of the component materials. The jars were sealed with lids and then placed on a Lau Dispersing Unit with a dispersion time of 3 hours. Components B and C were mixed with Component A prior to application.

[0268] The Second Coatings of Examples 13 through 15 were spray applied over the First Coating to a dry film thickness of between 1.4 to 1.7 mils using an air atomized spray gun.

[0269] The fully coated test panels coated with coating Examples 13 through 15 were allowed to age under ambient conditions for a minimum of 7 days, after which the panels were inscribed with a 10 cm by 10 cm X that was scribed into the panel surface to a sufficient depth to penetrate any surface coating and to expose the underlying metal. The scribed coated test panels were then placed into a 5% sodium chloride neutral salt spray cabinet according to ASTM B117 (exception: pH & salt concentration checked weekly as opposed to daily).

[0270] The ratings shown in TABLE 7 were at 456 hours of exposure for examples 13 through 15. The panels were rated according to the Scribe Corrosion and Scribe Shine ratings described above. The values were for the average of two replicates.

TABLE-US-00013 TABLE 7 Corrosion Test Results for Examples 13-15 Al 2024-T3 Bare Al 2024-T3 Clad Scribe Scribe Scribe Scribe Example # Description Corr. Shine Corr. Shine Comp Ex 13 Electrocoat Primer with Control Topcoat 20 90 30 95 Ex 14 Electrocoat Primer with DPDS Topcoat 5 40 5 70 Ex 15 Electrocoat Primer with Ethyl Tuads? 5 70 15 80 Topcoat

[0271] The corrosion data in TABLE 7 clearly shows that the DPDS and Ethyl Tuads? Coating Examples 14 and 15 when compared to Comparative Examples 13 provide measurably enhanced corrosion protection for both the A1 2024-T3 Bare and A1 2024-T3 Clad. Evidence of the enhanced corrosion protection is observed in the presence of lower or no amounts of corrosion in the scribe and the more shiny nature of the scribes.

Example 16Preparation of Hydroxypropylcarbamate Half-Capped Isophoronediisocyanate (IPDI) Reactant

[0272] A general procedure for making a hydroxypropylcarbamate half-capped isophoronediisocyanate was performed as follows:

##STR00017##

TABLE-US-00014 Charge # Material Amount (g) 1 Isophoronediisocyanate 1112.0 2 Methyl isobutyl ketone 537.8 3 Dibutyltindilaurate 1.7 4 Carbalink HPC (95%).sup.1 626.8 .sup.1Hydroxypropylcarbamate. Available commercially as Carbalink HPC from Huntsman

[0273] Charges 1-3 were added to a flask set up for total reflux with stirring under nitrogen. The mixture was heated to a temperature of 60? C. Charge 4 was added over 2 hours through an addition funnel while the resulting exotherm was maintained under 70? C. After 2 hours, the mixture was titrated for isocyanate (NCO) equivalent weight and found to have a value of 463 g/eq of NCO (theoretical of 456 g/eq). The mixture was then cooled to 40? C. and poured out. Final solids were 75.6%. The solids content was determined by adding a quantity of the dispersion to a tared aluminum dish, recording the weight of the dispersion and dish, heating the test specimen in the dish for 60 minutes at 110? C. in an oven, allowing the dish to cool, reweighing the dish to determine the amount of non-volatile content remaining, and determining the solids content by dividing the weight of the non-volatile content by the total sample weight and multiplying by 100. This procedure was used to determine the solids content in each of the examples below. Final z-average molecular weight (Mz) of the resin was determined to be 674 g/mol. The molecular weight was determined by Gel Permeation Chromatography using Waters 2695 separation module with a Waters 410 differential refractometer (RI detector), polystyrene standards having molecular weights of from approximately 500 g/mol to 900,000 g/mol, tetrahydrofuran (THF) with lithium bromide (LiBr) as the eluent at a flow rate of 0.5 mL/min, and one Asahipak GF-510 HQ column for separation. This procedure was used in each of the examples below.

Comparative Example 17Preparation of a Carbamate-Functional Phosphated Epoxy Resin without Corrosion Inhibitor

[0274] A procedure for making a carbamate-functional phosphated epoxy resin without corrosion inhibitor was performed as follows:

TABLE-US-00015 Charge # Material Amount (g) 1 Bisphenol-A Diglycidyl Ether 491.7 2 Bisphenol-A 158.4 3 Butyl carbitol formal 20.1 4 Ethyltriphenylphosphonium Bromide 0.4 5 Methyl isobutyl ketone 94.6 6 Dibutyltindilaurate 0.9 7 Hydroxypropylcarbamate half-capped 283.9 isophoronediisocyanate from Example 16 8 Butyl CELLOSOLVE.sup.2 101.2 9 2-Ethyl-1-hexanol 94.4 10 85% Phosphoric Acid 23.3 11 Phenylphosphonic Acid 21.3 12 Ektasolve EEH.sup.3 156.5 13 Deionized water 50.6 14 Diisopropanolamine 80.9 15 Cymel 1130.sup.4 328.9 16 Deionized water 623.3 17 Deionized water 1855.5 18 Deionized water 400.0 .sup.22-Butoxyethanol available from Dow Chemical Company .sup.3Ethylene glycol 2-ethylhexyl ether available from Eastman Chemical Company .sup.4Cymel 1130 a methylated/n-butylated melamine-formaldehyde crosslinker available from Allnex

[0275] Charges 1-4 were added to a flask set up for total reflux with stirring under nitrogen and heated to 130? C. and allowed to exotherm to 160? C. The mixture was held at 160? C. for 1 hour. After 1 hour, charge 5 was added while cooling to 80? C. When 80? C. was reached, charge 6 was added followed by charge 7 over 1 hour. After 1 hour, residual NCO was checked by IR and none remained. The mixture was then warmed to 90? C. When 90? C. was reached, charges 8-9 were added followed by charges 10-12 (predissolved at ambient temperature). The mixture was allowed to exotherm and the temperature was adjusted to 120? C. The mixture was held at that temperature for 30 minutes, then cooled to 100? C. Charge 13 was added slowly and the mixture was held at 100? C. for 1 hour, then cooled to 90? C. Charge 14 was added followed by charge 15. The mixture was stirred for 30 minutes as the temperature was readjusted to 90? C. The resulting mixture was then reverse thinned into charge 16, which was at ambient temperature, and held for 30 minutes. Charge 17 was then added and held for 30 minutes. Charge 18 was then added and held for 30 min. Following the final hold time, the flask set-up was switched to total distillation and the mixture was placed under 21-22 inches of vacuum. The temperature was increased to 55? C. and the mixture was stripped until methyl isobutyl ketone was less than 0.1% as determined by gas chromatography. Final solids were 31.4%. Final z-average molecular weight of the resin was 234,329 g/mol.

Example 18Preparation of a Carbamate-Functional Phosphated Epoxy Resin with Corrosion Inhibitor

[0276] A procedure for making a carbamate-functional phosphated epoxy resin with 30% by weight 2,2-dipyridyl disulfide (DPDS) corrosion inhibitor was performed as follows:

TABLE-US-00016 Charge # Material Amount (g) 1 Bisphenol-A Diglycidyl Ether 122.9 2 Bisphenol-A 39.6 3 Butyl carbitol formal 5.0 4 Ethyltriphenylphosphonium Bromide 0.1 5 Methyl isobutyl ketone 23.7 6 Dibutyltindilaurate 0.2 7 Hydroxypropylcarbamate half-capped 71.0 isophoronediisocyanate from Example 16 8 Butyl CELLOSOLVE 25.3 9 2-Ethyl-1-hexanol 23.6 10 85% Phosphoric Acid 5.8 11 Phenylphosphonic Acid 5.3 12 Ektasolve EEH 39.1 13 Deionized water 12.6 14 Diisopropanolamine 20.2 15 Cymel 1130 82.2 16 DPDS (2,2-dipyridyl disulfide).sup.1 141.0 17 Deionized water 286.0 18 Deionized water 662.7 19 Deionized water 80.0 .sup.12,2-dipyridyl disulfide available from Combi-Blocks

[0277] Charges 1-4 were added to a flask set up for total reflux with stirring under nitrogen and heated to 130? C. and allowed to exotherm to 160? C. The mixture was held at 160? C. for 1 hour. After 1 hour, charge 5 was added while cooling to 80? C. When 80? C. was reached, charge 6 was added followed by charge 7 over 1 hour. After 1 hour, residual NCO was checked by IR and none remained. The mixture was then warmed to 90? C. When 90? C. was reached, charges 8-9 were added followed by charges 10-12 (predissolved at ambient temperature). The mixture was allowed to exotherm and the temperature was adjusted to 120? C. The mixture was held at that temperature for 30 minutes, then cooled to 100? C. Charge 13 was added slowly and the mixture was held at 100? C. for 1 hour, then cooled to 90? C. Charge 14 was added followed by charge 15, which was followed by charge 16. The mixture was stirred for 30 minutes as the temperature was readjusted to 90? C. The resulting mixture was then reverse thinned into charge 17, which was at ambient temperature, and held for 30 minutes. Charge 18 was then added and held for 30 minutes. Charge 19 was then added and held for 30 min. Following the final hold time, the flask set-up was switched to total distillation and the mixture was placed under 21-22 inches of vacuum. The temperature was increased to 55? C. and the mixture was stripped until methyl isobutyl ketone was less than 0.1% as determined by gas chromatography. Final solids were 27.6%. Final z-average molecular weight of the resin was 283,495 g/mol.

Example 19Preparation of a Methylated Melamine-Formaldehyde Curing Agent Comprising High Molecular Weight Volatile Groups

[0278] A procedure for making a Butyl CELLOSOLVE-modified curing agent was performed as follows:

TABLE-US-00017 Charge # Material Amount (g) 1 Cymel 303.sup.1 390.0 2 Butyl CELLOSOLVE 350.0 3 Phenyl phosphonic acid 2.0 .sup.1Cymel 303 is a methylated melamine-formaldehyde curing agent available from Allnex

[0279] Charges 1-3 were added to a flask set up for total distillation with stirring under nitrogen. The mixture was heated to reflux and remained there for 2 hours until methanol distillate stalled. After 125 mL of total distillate volume evolved, the mixture was cooled to 40? C. and was poured out.

Example 20Preparation of a Carbamate-Functional Phosphated Epoxy Resin With Corrosion Inhibitor and Curing Agent With High Molecular Weight Volatile Groups

[0280] A procedure for making a carbamate-functional phosphated epoxy resin with 20% by weight 2,2-dipyridyl disulfide (DPDS) corrosion inhibitor and a curing agent comprising high molecular weight volatile groups (BuCell-modified curing agent) was performed as follows:

TABLE-US-00018 Charge # Material Amount (g) 1 Bisphenol-A Diglycidyl Ether 116.8 2 Bisphenol-A 37.6 3 Butyl carbitol formal 4.8 4 Ethyltriphenylphosphonium Bromide 0.1 5 Methyl isobutyl ketone 22.5 6 Dibutyltindilaurate 0.2 7 Hydroxypropylcarbamate half-capped 67.4 isophoronediisocyanate from Example 16 8 Butyl CELLOSOLVE 24.0 9 2-Ethyl-1-hexanol 22.4 10 85% Phosphoric Acid 5.5 11 Phenylphosphonic Acid 5.1 12 Ektasolve EEH 37.2 13 Deionized water 12.0 14 Diisopropanolamine 19.2 15 Methylated Melamine-Formaldehyde Curing 162.9 Agent Comprising High Molecular Weight Volatile Groups from Example 19 16 DPDS (2,2-dipyridyl disulfide) 99.3 17 Deionized water 279.8 18 Deionized water 616.2 19 Deionized water 76.0

[0281] Charges 1-4 were added to a flask set up for total reflux with stirring under nitrogen and heated to 130? C. and allowed to exotherm to 160? C. The mixture was held at 160? C. for 1 hour. After 1 hour, charge 5 was added while cooling to 80? C. When 80? C. was reached, charge 6 was added followed by charge 7 over 1 hour. After 1 hour, residual NCO was checked by IR and none remained. The mixture was then warmed to 90? C. When 90? C. was reached, charges 8-9 were added followed by charges 10-12 (predissolved at ambient temperature). The mixture was allowed to exotherm and the temperature was adjusted to 120? C. The mixture was held at that temperature for 30 minutes, then cooled to 100? C. Charge 13 was added slowly and the mixture was held at 100? C. for 1 hour, then cooled to 90? C. Charge 14 was added followed by charge 15, which was followed by charge 16. The mixture was stirred for 30 minutes as the temperature was readjusted to 90? C. The resulting mixture was then reverse thinned into charge 17, which was at ambient temperature, and held for 30 minutes. Charge 18 was then added and held for 30 minutes. Charge 19 was then added and held for 30 min. Following the final hold time, the flask set-up was switched to total distillation and the mixture was placed under 21-22 inches of vacuum. Temperature was increased to 55? C. and the mixture was stripped until methyl isobutyl ketone was less than 0.1% as determined by gas chromatography. Final solids were 25.8%. Final z-average molecular weight of the resin was 260,847 g/mol.

Example 21Preparation of a Methylated Melamine-Formaldehyde Curing Agent Comprising High Molecular Weight Volatile Groups

[0282] A procedure for making a Butyl CARBITOL-modified curing agent was performed as follows:

TABLE-US-00019 Charge # Material Amount (g) 1 Cymel 303.sup.1 994.9 2 Butyl CARBITOL 1,215.0 3 Phenyl phosphonic acid 5.0 .sup.1Cymel 303 is a methylated melamine-formaldehyde curing agent available from Allnex

[0283] Charges 1-3 were added to a flask set up for total distillation with stirring under nitrogen. The mixture was heated to reflux and remained there for 2 hours until methanol distillate stalled. After 240.4 mL of total distillate volume evolved, the mixture was cooled to 40? C. and was poured out.

Example 22Preparation of a Carbamate-Functional Phosphated Epoxy Resin With Corrosion Inhibitor and Curing Agent With High Molecular Weight Volatile Groups

[0284] A procedure for making a carbamate-functional phosphated epoxy resin with 15% by weight ETHYL TUADS (tetraethyl thiuram disulfide (TETD)) corrosion inhibitor and a curing agent comprising high molecular weight volatile groups (BuCarb-modified curing agent) was performed as follows:

TABLE-US-00020 Charge # Material Amount (g) 1 Bisphenol-A Diglycidyl Ether 110.8 2 Bisphenol-A 35.6 3 Butyl carbitol formal 4.5 4 Ethyltriphenylphosphonium Bromide 0.09 5 Methyl isobutyl ketone 21.3 6 Dibutyltindilaurate 0.21 7 Hydroxypropylcarbamate half-capped 68.6 isophoronediisocyanate from Example 16 8 Butyl CELLOSOLVE 22.8 9 2-Ethyl-1-hexanol 21.3 10 85% Phosphoric Acid 5.3 11 Phenylphosphonic Acid 4.8 12 Ektasolve EEH 35.2 13 Deionized water 11.4 14 Diisopropanolamine 18.2 15 Methylated Melamine-Formaldehyde Curing 185.0 Agent Comprising High Molecular Weight Volatile Groups from Example 21 16 ETHYL TUADS.sup.1 72.6 17 Deionized water 275.4 18 Deionized water 600.4 19 Deionized water 72.0 .sup.1Commercially available from Vanderbilt Chemicals

[0285] Charges 1-4 were added to a flask set up for total reflux with stirring under nitrogen and heated to 130? C. and allowed to exotherm to 160? C. The mixture was held at 160? C. for 1 hour. After 1 hour, charge 5 was added while cooling to 80? C. When 80? C. was reached, charge 6 was added followed by charge 7 over 1 hour. After 1 hour, residual NCO was checked by IR and none remained. The mixture was then warmed to 90? C. When 90? C. was reached, charges 8-9 were added followed by charges 10-12 (predissolved at ambient temperature). The mixture was allowed to exotherm and the temperature was adjusted to 120? C. The mixture was held at that temperature for 30 minutes, then cooled to 100? C. Charge 13 was added slowly and the mixture was held at 100? C. for 1 hour, then cooled to 90? C. Charge 14 was added followed by charge 15, which was followed by charge 16. The mixture was stirred for 30 minutes as the temperature was readjusted to 90? C. The resulting mixture was then reverse thinned into charge 17, which was at ambient temperature, and held for 30 minutes. Charge 18 was then added and held for 30 minutes. Charge 19 was then added and held for 30 min. Following the final hold time, the flask set-up was switched to total distillation and the mixture was placed under 21-22 inches of vacuum. Temperature was increased to 55? C. and the mixture was stripped until methyl isobutyl ketone was less than 0.1%. Final solids were 28.53%. Final molecular weight by GPC (Mz) was 510,532.

Comparative Example 23Preparation of a Carbamate-Functional Phosphated Epoxy Resin With Curing Agent With High Molecular Weight Volatile Groups

[0286] A procedure for making a carbamate-functional phosphated epoxy resin with 20% by weight of comparative 4,4-dipyridyl disulfide and a curing agent comprising high molecular weight volatile groups (BuCarb-modified curing agent) was performed as follows:

TABLE-US-00021 Charge # Material Amount (g) 1 Bisphenol-A Diglycidyl Ether 57.8 2 Bisphenol-A 18.6 3 Butyl carbitol formal 2.4 4 Ethyltriphenylphosphonium Bromide 0.05 5 Methyl isobutyl ketone 11.1 6 Dibutyltindilaurate 0.11 7 Hydroxypropylcarbamate half-capped 35.8 isophoronediisocyanate from Example 16 8 Butyl CELLOSOLVE 11.9 9 2-Ethyl-1-hexanol 11.1 10 85% Phosphoric Acid 2.7 11 Phenylphosphonic Acid 2.5 12 Ektasolve EEH 18.4 13 Deionized water 5.9 14 Diisopropanolamine 9.5 15 Methylated Melamine-Formaldehyde Curing 82.1 Agent Comprising High Molecular Weight Volatile Groups from Example 21 16 4,4-Dipyridyl Disulfide.sup.1 50.0 17 Deionized water 281.6 18 Deionized water 141.9 19 Deionized water 310.5 .sup.1Commercially available from Sigma Aldrich

[0287] Charges 1-4 were added to a flask set up for total reflux with stirring under nitrogen and heated to 130? C. and allowed to exotherm to 160? C. The mixture was held at 160? C. for 1 hour. After 1 hour, charge 5 was added while cooling to 80? C. When 80? C. was reached, charge 6 was added followed by charge 7 over 1 hour. After 1 hour, residual NCO was checked by IR and none remained. The mixture was then warmed to 90? C. When 90? C. was reached, charges 8-9 were added followed by charges 10-12 (predissolved at ambient temperature). The mixture was allowed to exotherm and the temperature was adjusted to 120? C. The mixture was held at that temperature for 30 minutes, then cooled to 100? C. Charge 13 was added slowly and the mixture was held at 100? C. for 1 hour, then cooled to 90? C. Charge 14 was added followed by charge 15, which was followed by charge 16. The mixture was stirred for 30 minutes as the temperature was readjusted to 90? C. The resulting mixture was then reverse thinned into charge 17, which was at ambient temperature, and held for 30 minutes. Charge 18 was then added and held for 30 minutes. Charge 19 was then added and held for 30 min. Following the final hold time, the flask set-up was switched to total distillation and the mixture was placed under 21-22 inches of vacuum. Temperature was increased to 55? C. and the mixture was stripped until methyl isobutyl ketone was less than 0.1%. Final solids were 27.97%. Final molecular weight by GPC (Mz) was 199,532.

Preparation and Evaluation of Comparative and Experimental Electrodepositable Coating Compositions

[0288] The carbamate-functional phosphated epoxy resins prepared above were then formulated into primer electrodepositable coating compositions at 20% non-volatile compositions with a pigment to binder ratio of 0.20 using the charge amounts indicated below:

TABLE-US-00022 Electrodepositable coating composition Comp. Ex. Example Comp. Ex. Example: A Example B Example C D E Charge # Description: No 20% by wt. 30% by wt. 15% by 20% by Inhibitor 2,2'-DPDS 2,2'-DPDS wt. wt. 4,4'- with Curing ETHYL DPDS Agent with TUADS with High with Curing Molecular Curing Agent Weight Agent with High Volatile with High Molecular Groups Molecular Weight Weight Volatile Volatile Groups Groups Charge 1 Comp. Ex. 1401.36 (Resin) 17 Example 18 1228.00 Example 20 1315.00 Example 22 1270.00 Comp. Ex. 613.90 23 Charge 2 Pigment 239.01 184.37 184.67 197.06 93.39 Paste.sup.1 Charge 3 Deionized 1159.63 660.56 749.96 841.48 386.73 Water .sup.1A gray pigment paste commercially available from PPG as ACPP2120

[0289] The electrodepositable coating compositions were prepared according to the following procedure: Charge 1 was added to a 1 gallon plastic bucket and agitation was started. Charge 2 was added slowly over 5 minutes. Finally, Charge 3 was added over 5 minutes. The resulting mixture stirred for an additional 15 minutes. The electrodepositable coating compositions were then ultrafiltered to remove 50% of the original mass of the bath which was replaced with additional deionized water to return it to the original starting weight.

[0290] Test specimens were prepared by applying coatings from the electrodepositable coating compositions onto test coupons consisting of 0.032?3?4?2024 T3 bare aluminum alloy panels. The panels were first cleaned using an acetone wipe. Panels were then immersed in BONDERITE? C-AK 298 ALKALINE CLEANER (previously known as Ridoline? 298 and commercially available from Henkel) for 2 minutes at 130? F. followed by a 1-minute immersion in tap water and a spray rinse of tap water. The panels were then immersed in a deoxidizing bath consisting of BONDERITE? C-IC DEOXDZR.sub.6MU AERO/BONDERITE? C-IC DEOXDZR 16R AERO (previously known as Turco? Deoxidizer 6 Makeup and Turco? Deoxidizer 16 Replenisher, both commercially available from Henkel) for 2 minutes and 30 seconds at ambient conditions; followed by a 1-minute immersion in tap water and finally a spray rinse of deionized water. The panels were allowed to dry under ambient conditions for 1-2 hours prior to electrocoat application. The electrodepositable coating compositions were electrodeposited onto the test panels using 0.3 amps for 90 seconds at a bath temperature of 75? F. using voltages as listed in the table below to achieve a dry film thickness of 0.89?0.08 mils (21.61?2.03 microns).

TABLE-US-00023 Example Comp. Ex. A Example B Example C Example D Comp. Ex. E Description No Inhibitor 20% by wt. 30% by wt. 15% by wt. 20% by wt. 2,2-DPDS DPDS ETHYL 4,4-DPDS with Curing TUADS with Curing Agent with with Curing Agent with High Agent with High Molecular High Molecular Weight Molecular Weight Volatile Weight Volatile Groups Volatile Groups Groups Voltage 160 70 60 40 70

[0291] The electrodeposited coatings on the panels were then cured by baking the coated panels for 30 minutes at 225? F. (107.2? C.). The panels were coated and evaluated in duplicate.

[0292] The ability of the coatings to inhibit corrosion of the substrate were evaluated as follows: The test panels were inscribed with a 10 cm by 10 cm X that was scribed into the panel surface to a sufficient depth to penetrate any surface coating and to expose the underlying metal. The scribed coated test panels were then placed into a 5% sodium chloride neutral salt spray cabinet according to ASTM B117 (exception: pH & salt concentration checked weekly as opposed to daily) for at least 1,584 hours of exposure (indicated in the table below). The panels were visually inspected following exposure and evaluated for scribe corrosion, scribe shine, scribe blisters, face blisters and maximum scribe blister size. Scribe corrosion was evaluated on a scale of 0 to 100 and represents the percentage of scribe area showing visible corrosion with 0 indicating no scribe corrosion and 100 indicating corrosion over the entire length of the scribe. Less scribe corrosion indicates better corrosion performance. Scribe shine was evaluated on a scale of 0 to 100 and represents the percentage of scribe which is dark and/or tarnished with 0 indicating no dark or tarnished portions of the scribe and 100 indicating dark color and/or tarnish over the entire length of the scribe. Less discoloration and/or tarnish indicates better corrosion performance. The scribe and face blisters represent the total number of blisters adjacent to scribe (i.e., scribe blisters) and not adjacent to the scribe (i.e., face blisters) with blisters being counted up to a maximum of 30. Fewer blisters indicate better corrosion performance. The maximum scribe blister size is the size of the largest blister adjacent to the scribe is recorded as one of four values: 0 for no blisters being present; <1.25 mm wherein the largest scribe blister is less than 1.25mm diameter; >1.25 mm wherein the largest scribe blister is larger than 1.25 mm and less than 2.5 mm; and >2.5 mm wherein the largest scribe blister is larger than 2.5 mm. Smaller maximum scribe blister size indicates better corrosion performance. The results are provided in the table below:

TABLE-US-00024 Hours of Salt Spray Scribe Scribe Scribe Face Max. Scribe Example Description Exposure Corrosion Shine Blisters Blisters Blister Size Comp. No Inhibitor 1632 35 95 3 0 <1.25 mm Ex. A with 35 95 5 0 <1.25 mm Unmodified Crosslinker Ex. B 20% by wt. 1632 5 80 2 0 <1.25 mm 2,2'-DPDS 5 85 4 0 <1.25 mm with Curing Agent with High Molecular Weight Volatile Groups Ex. C 30% by wt. 1632 20 80 8 0 <1.25 mm 2,2'-DPDS 25 85 6 0 <1.25 mm Ex. D 15% Ethyl 1584 20 90 13 0 <1.25 mm Tuads with 25 90 7 0 <1.25 mm Bucarb Modified Crosslinker Comp. 20% 4,4- 1584 40 95 13 0 <1.25 mm Ex. E DPDS with 40 95 10 0 <1.25 mm Bucell- Modified crosslinker

[0293] The corrosion data demonstrates that Example B including 20% by weight 2,2-DPDS and a curing agent having high molecular weight volatile groups, Example C including 30% by weight 2,2-DPDS, and Example D including ETHYL TUADS and a curing agent having high molecular weight volatile groups measurably enhanced corrosion performance of the coated metal substrate as compared to Comparative Example A that did not contain a polysulfide corrosion inhibitor. Evidence of the enhanced corrosion protection is observed in the presence of lower amounts of corrosion in the scribe and the more shiny nature of the scribes.

[0294] In contrast, Comparative Example E that included 4,4-DPDS and a curing agent having high molecular weight volatile groups did not improve the corrosion performance by any of the above metrics performing the same or worse than Comparative Example A.

[0295] It will be appreciated by skilled artisans that numerous modifications and variations are possible in light of the above disclosure without departing from the broad inventive concepts described and exemplified herein. Accordingly, it is therefore to be understood that the foregoing disclosure is merely illustrative of various exemplary aspects of this application and that numerous modifications and variations can be readily made by skilled artisans which are within the spirit and scope of this application and the accompanying claims.