An Acrylic Polyester Resin and An Aqueous Coating Composition Containing the Same

Abstract

There is described an acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material. The polyester material is obtainable by polymerizing (i) a polyacid component, with (ii) a polyol component. At least one of the polyacid component and/or the polyol component comprises a monomer having an aliphatic group containing at least 15 carbon atoms. At least one of the polyacid component and/or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality. Also provided is an aqueous coating composition comprising the acrylic polyester resin and a packaging coated with the composition.

Claims

1. An acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing: i) a polyacid component, with ii) a polyol component, wherein at least one of the polyacid component and/or the polyol component comprises a monomer having an aliphatic group containing at least 15 carbon atoms; wherein at least one of the polyacid component and/or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality.

2. An aqueous coating composition, the aqueous coating composition comprising: a) an acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing: i) a polyacid component, with ii) a polyol component, wherein at least one of the polyacid component and/or the polyol component comprises a monomer having an aliphatic group containing at least 15 carbon atoms; wherein at least one of the polyacid component and/or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality, b) a crosslinking material.

3. A packaging coated on at least a portion thereof with a coating, the coating being derived from an aqueous coating composition, the aqueous coating composition comprising: a) an acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing: i) a polyacid component, with ii) a polyol component, wherein at least one of the polyacid component and/or the polyol component comprises a monomer having an aliphatic group containing at least 15 carbon atoms. wherein at least one of the polyacid component and/or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted with the polyester material via the use of said functionality, b) a crosslinking material.

4. A resin, coating composition or packaging according to any of claims 1 to 3, wherein the functional monomer comprises an ethylenically unsaturated monomer.

5. A resin, coating composition or packaging according to any of claims 1 to 4, wherein the functional monomer is selected from one or more of the following: maleic acid, maleic anhydride, fumaric acid, itaconic anhydride, itaconic acid, citraconic anhydride, citraconic acid, aconitic acid, aconitic anhydride, oxalocitraconic acid, oxalocitraconic anhydride, mesaconic acid, mesaconic anhydride, phenyl maleic acid, phenyl maleic anhydride, t-butyl maleic acid, t-butyl maleic anhydride, monomethyl fumarate, monobutyl fumarate, nadic acid, nadic anhydride, methyl maleic acid, methyl maleic anhydride, trimethylolpropane monoallyl ether.

6. A resin, coating composition or packaging according to any of claims 1 to 5, wherein the functional monomer is present as a proportion of the dry weight of the polyol or polyacid component, such as the polyacid component, in an amount of between 0.5 and 10 wt %, suitably between 1 and 5 wt %.

7. A resin, coating composition or packaging according to any of claims 1 to 6, wherein the aliphatic group of the aliphatic group-containing monomer comprises from 18 to 50 carbon atoms, such as from 20 to 46 carbon atoms, from 22 to 44 carbon atoms, from 24 to 42 carbon atoms, from 26 to 40 carbon atoms,

8. A resin, coating composition or packaging according to any of claims 1 to 7, wherein the aliphatic group of the aliphatic group-containing monomer comprises from 28 to 38 carbon atoms, or from 30 to 38 carbon atoms.

9. A resin, coating composition or packaging according to any of claims 1 to 8, wherein the aliphatic group of the aliphatic group-containing monomer is branched and/or comprises a cyclic group.

10. A resin, coating composition or packaging according to any of claims 1 to 9, wherein aliphatic group-containing monomer is a diacid.

11. A resin, coating composition or packaging according to any of claims 1 to 10, wherein the aliphatic group-containing monomer is a dimer fatty acid.

12. A resin, coating composition or packaging according to any of claims 1 to 11, wherein the aliphatic group-containing monomer is the dimerisation product of erucic acid, linolenic acid, linoleic acid, and/or oleic acid.

13. A resin, coating composition or packaging according to any of claims 1 to 12, wherein the polyacid component comprises one or more of the following: maleic acid; fumaric acid; itaconic acid; adipic acid; azelaic acid; succinic acid; sebacic acid; glutaric acid; decanoic diacid; dodecanoic diacid; phthalic acid; isophthalic acid; 5-tert-butylisophthalic acid; tetrachlorophthalic acid; tetrahydrophthalic acid; trimellitic acid; naphthalene dicarboxylic acid; naphthalene tetracarboxylic acid; terephthalic acid; hexahydrophthalic acid; methylhexahydrophthalic acid; dimethyl terephthalate; cyclohexane dicarboxylic acid; chlorendic anhydride; 1,3-cyclohexane dicarboxylic acid; 1,4-cyclohexane dicarboxylic acid; tricyclodecane polycarboxylic acid; endomethylene tetrahydrophthalic acid; endoethylene hexahydrophthalic acid; cyclohexanetetra carboxylic acid; cyclobutane tetracarboxylic; esters and anhydrides of all the aforementioned acids and combinations thereof.

14. A resin, coating composition or packaging according to any of claims 1 to 13, wherein the polyacid component comprises one or more of the following: terephthalic acid (TPA), isophthalic acid (IPA), dimethyl isophthalic acid, 1,4 cyclohexane dicarboxylic acid, hexahydrophthalic anhydride, 2,6-naphthalene dicarboxylic acid, phthalic anhydride, maleic anhydride, fumaric anhydride, suitably additionally comprising the aliphatic group-containing monomer.

15. A resin, coating composition or packaging according to any of claims 1 to 14, wherein the polyacid component comprises the aliphatic group-containing monomer and one or more of the following: dimethyl terephthalate, isophthalic acid, hexahydrophthalic anhydride, cyclohexane 1,4-dicarboxylic acid.

16. A resin, coating composition or packaging according to any of claims 1 to 15, wherein the polyol component comprises one or more of the following: 2,2,4,4-tetraalkylcyclobutane-1,3-diol (TACD); alkylene glycols, such as ethylene glycol; propylene glycol; diethylene glycol; dipropylene glycol; triethylene glycol; tripropylene glycol; hexylene glycol; polyethylene glycol; polypropylene glycol and neopentyl glycol; hydrogenated bisphenol A; cyclohexanediol; propanediols including 1,2-propanediol; 1,3-propanediol; butyl ethyl propanediol; 2-methyl-1,3-propanediol; and 2-ethyl-2-butyl-1,3-propanediol; butanediols including 1,4-butanediol; 1,3-butanediol; and 2-ethyl-1,4-butanediol; pentanediols including trimethyl pentanediol and 2-methylpentanediol; cyclohexanedimethanol; hexanediols including 1,6-hexanediol; caprolactonediol (for example, the reaction product of epsilon-capro lactone and ethylene glycol); hydroxyalkylated bisphenols; polyether glycols, for example, poly(oxytetramethylene) glycol; trimethylol propane; pentaerythritol; di-pentaerythritol; trimethylol ethane; trimethylol butane; dimethylol cyclohexane; bio-derived polyols such as glycerol, sorbitol and isosorbide; and the like or combinations thereof.

17. A resin, coating composition or packaging according to any of claims 1 to 16, wherein the polyol component comprises one or more polyols having at least three hydroxyl groups, such as one or more selected from trimethylol propane; pentaerythritol; di-pentaerythritol; trimethylol ethane; trimethylol butane; and bio-derived polyols such as one or more selected from glycerol and sorbitol, for example trimethylol propane.

18. A resin, coating composition or packaging according to any of claims 1 to 17, wherein the polyol having at least three hydroxyl groups is present as a proportion of the dry weight of the polyol component in an amount of from 0.1 to 10 wt %, such as from 0.5 to 8 wt % or from 0.7 to 6 wt %, for example from 0.8 to 5 wt % or from 0.9 to 4 wt %, suitably from 1 to 3 wt % or from 1 to 2 wt %.

19. A resin, coating composition or packaging according to any of claims 1 to 18, wherein the polyol component comprises one or more of the following: 2-methyl propanediol (2-MPD), 2,2,4,4-tetraalkylcyclobutane-1,3-diol, such as 2,2,4,4-tetramethylcyclobutane-1,3-diol (TMCD), neopentyl glycol (NPG), 1,4-cyclohexane dimethanol (CHDM), butyl ethyl propane diol (BEPD), trimethylolppropane (TMP) or 1,6 hexanediol.

20. A resin, coating composition or packaging according to any of claims 1 to 19, wherein the polyol component comprises one or more of TMCD, 2-methy-1,3 propanediol, cyclohexanedimethanol and/or trimethylolppropane (TMP).

21. A resin, coating composition or packaging according to any of claims 1 to 19, wherein the polyol component comprises one or more of the following: 1,4-cyclohexane dimethanol (CHDM), and trimethylolppropane (TMP).

22. A resin, coating composition or packaging according to any of claims 1 to 21, wherein the polyacid component and/or the polyol component comprises a sulfonated monomer.

23. A resin, coating composition or packaging according to any of claims 1 to 22, wherein the sulfonated monomer comprises one or more of: 5-(sodiosulfo)-isophthalic acid, dimethyl 5-(sodiosulfo)isophalate, 5-(lithiosulfo)isophthalic acid, bis(2-hydroxyethyl)-5-(sodiosulfo)isophthalate.

24. A resin, coating composition or packaging according to any of claims 1 to 23, wherein the polyester material comprises an Mn from 1,000 Daltons (Da=g/mole) to 15,000 Da, suitably from 2,000 Da to 10,000 Da, such as from 3,000 Da to 8,000 Da, or even from 4,000 to 7,000 Da.

25. A resin, coating composition or packaging according to any of claims 1 to 24, wherein the polyester material has a gross OHV of from 0 to 120 mg KOH/g, suitably from 5 to 100 mg KOH/g, such as from 5 to 80 mg KOH/g, or from 5 to 50 mg KOH/g, or from 7 to 40 mg KOH/g, suitably from 10 to 30 mg KOH/g or 10 to 20 mg KOH/g.

26. A resin, coating composition or packaging according to any of claims 1 to 25, wherein the polyester material has an AV from 0 to 20 KOH/g, suitably from 0 to 10 mg KOH/g, such as less than 5 or even less than 3.

27. A resin, coating composition or packaging according to any of claims 1 to 326, wherein the polyester material has a Mn of from 3,000 to 8,000 Da, a gross OHV of from 5 to 50 mg KOH/g and an acid value of from 0 to 10 mg KOH/g.

28. A resin, coating composition or packaging according to any of claims 1 to 27, wherein the polyester material has a Mn of from 4,000 to 7,000 Da, a gross OHV of from 10 to 20 mg KOH/g and an acid value of less than 5 mg KOH/g.

29. A resin, coating composition or packaging according to any of claims 1 to 28, wherein the acrylic polyester resin is formed from the polyester material and an acrylic modification polymer in a weight ratio of from 95 wt % to 55 wt % polyester material to from 45 wt % to 5 wt % acrylic modification polymer, such as from 90 wt % to 55 wt % polyester material to from 45 wt % to 10 wt % acrylic modification polymer, or from 90 wt % to 55 wt % polyester material to from 45 wt % to 10 wt % acrylic modification polymer, such as a weight ratio of from 90 wt % to 60 wt % polyester material to from 40 wt % to 10 wt % acrylic modification polymer, such as a weight ratio of from 85 wt % to 65 wt % polyester material to from 35 wt % to 15 wt % acrylic modification polymer or from 85 wt % to 75 wt % polyester material to from 25 wt % to 15 wt % acrylic modification polymer.

30. A resin, coating composition or packaging according to any of claims 1 to 29, wherein an acrylic modification polymer is polymerized in the presence of the polyester material to form an acrylic modified polyester resin.

31. A resin, coating composition or packaging according to any of claims 1 to 30, wherein the acrylic modification polymer is formed from one or more of the following monomers: methyl(meth)acrylate, ethyl(meth)acrylate, butyl (meth)acrylate, isobornyl (meth)acrylate, hydroxyethyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, (meth)acrylic acid; cyclohexyl (meth)acrylate, allyl (meth)acrylate, dimethylamino ethyl methacrylate. butylamino ethyl (meth)acrylate, HEMA phosphate (such as ethylene glycol methacrylate phosphate).

32. A resin, coating composition or packaging according to any of claims 1 to 31, wherein the acrylic monomers comprises a hydroxyl functional monomer, such as hydroxyethyl (meth)acrylate.

33. A resin, coating composition or packaging according to any of claims 1 to 32, wherein the hydroxyl functional monomer is present by dry weight of the acrylic modification polymer in an amount of from 5 to 40 wt %, such as from 5 to 30 wt % or from 10 to 20 wt %.

34. A resin, coating composition or packaging according to any of claims 1 to 33, wherein the acrylic polyester resin, which may be an acrylic modified polyester resin, is present in the aqueous coating composition in an amount of between 50 to 99 wt % (based on dry weight of the aqueous coating composition), suitably, in an amount of between 60 to 95 wt % (based on dry weight of the aqueous coating composition).

35. A resin, coating composition or packaging according to any of claims 1 to 34, wherein the acrylic monomers comprise a ratio of methacrylate monomers to acrylate monomers of at least 1:1, such as at least 2:1 or at least 3:1 or at least 4:1, suitably at least 5:1.

36. A resin, coating composition or packaging according to any of claims 1 to 35, wherein the acrylic polyester resin, which may be an acrylic modified polyester resin, has an Mn from 1,000 Daltons (Da=g/mole) to 15,000 Da, suitably from 2,000 Da to 12,000 Da, such as from 3,000 Da to 9,000 Da, or even from 3,500 to 8,000 Da.

37. A resin, coating composition or packaging according to any of claims 1 to 36, wherein the acrylic polyester resin has a gross OHV from 0 to 120 mg KOH/g, such as from 5 to 100 mg KOH/g, or from 10 to 60 mg KOH/g, or even from 10 to 50 mg KOH/g, such as from 10 to 30 mg KOH/g.

38. A resin, coating composition or packaging according to any of claims 1 to 37, wherein the acrylic polyester resin has an AV from 10 to 80 KOH/g, such as from 10 to 60 mg KOH/g, such as from 10 to 50 mg KOH/g or from 15 to 40 mg KOH/g, or from 15 to 35 mg KOH/g.

39. A resin, coating composition or packaging according to any of claims 1 to 38, wherein the acrylic polyester resin, which may be an acrylic modified polyester resin, has a Mn of 3,000 to 9,000 Da, a gross OHV of from 10 to 50 mg KOH/g and an AV of from 15 to 40 mg KOH/g.

40. A resin, coating composition or packaging according to any of claims 1 to 39, wherein the acrylic polyester resin, which may be an acrylic modified polyester resin, has a Mn of 3,500 to 8,000 Da, a gross OHV of from 10 to 30 mg KOH/g and an AV of from 15 to 35 mg KOH/g.

41. A coating composition or packaging according to any of claims 2 to 40, wherein the crosslinking material comprises one or more of a phenolic resin, melamine, benzoguanamine or melamine.

42. A coating composition or packaging according to any of claims 2 to 41, wherein the crosslinking material comprises benzoguanamine.

43. A coating composition or packaging according to any of claims 2 to 42, wherein the aqueous coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF) and derivatives thereof.

44. A coating composition or packaging according to any of claims 2 to 43, wherein the aqueous coating composition is substantially free of styrene.

45. A coating composition or packaging according to any of claims 2 to 44, wherein the aqueous coating composition is substantially free of formaldehyde.

46. A coating composition or packaging according to any of claims 2 to 45, wherein the aqueous coating composition further comprises an adhesion promoter.

47. A coating composition or packaging according to claim 46, wherein the adhesion promoter comprises an acidic polyester material.

48. A coating composition or packaging according to claim 47, wherein the acidic polyester generally comprises the reaction product of: (a) a polyester having an Mn of 2000 to 10,000, a hydroxyl number of 20 to 75, and an acid value of 15 to 25; the polyester being a polycondensate of: (i) a polyol component comprising a mixture of diols and triols, (ii) a polyacid component comprising an alpha, beta-ethylenically unsaturated polycarboxylic acid, and (b) a phosphorus acid.

49. A coating composition according to any of claims 2 to 48, wherein the coating composition has a solids content of from 10 to 60% by weight of the coating composition, such as from 15 to 50 wt % or suitably from 20 to 40 wt %.

50. A packaging according to any of claims 3 to 49, wherein the packaging comprises a food or beverage can or aerosol can.

51. A method of forming an acrylic modified polyester resin, the method comprising polymerizing an acrylic modification polymer in the presence of a polyester material, the polyester material being obtainable by polymerizing i) a polyacid component, with ii) a polyol component, wherein at least one of the polyacid component and/or the polyol component comprises a monomer having an aliphatic group containing at least 15 carbon atoms; wherein at least one of the polyacid component and/or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality.

52. A method of preparing an aqueous coating composition, the method comprising dispersing an acrylic modified polyester resin and a crosslinking material in an aqueous medium, the acrylic modified polyester resin being obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing: i) a polyacid component, with ii) a polyol component, wherein at least one of the polyacid component and/or the polyol component comprises a monomer having an aliphatic group containing at least 15 carbon atoms; wherein at least one of the polyacid component and/or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality.

53. A method of coating at least a portion of a packaging, the method comprising applying an aqueous coating composition to a packaging composition, the aqueous coating composition comprising an acrylic modified polyester resin and a crosslinking material, the acrylic modified polyester resin being obtainable by grafting an acrylic polymer onto a polyester material, the polyester material being obtainable by polymerizing: i) a polyacid component, with ii) a polyol component, wherein at least one of the polyacid component and/or the polyol component comprises a monomer having an aliphatic group containing at least 15 carbon atoms; wherein at least one of the polyacid component and/or the polyol component comprises a functional monomer operable to impart functionality on to the polyester resin, such that an acrylic polymer may be grafted onto the polyester material via the use of said functionality, and curing the aqueous coating composition to form a coating.

54. A packaging or method according to any of claims 3 to 68, wherein the packaging is metal packaging, such as a metal can.

Description

EXAMPLES

Method for the Formation of the Aqueous Coatings

[0284] The details of inventive aqueous coating 1 and comparative aqueous coating 2 are shown in Tables 1 to 4. Coating 1 shows unsaturated, hydroxyl functional polyesters formed from monomers including a monomer having at least 15 carbon atoms (Pripol 1010). Comparative coating 2 shows an unsaturated, hydroxyl functional polyester without a monomer having at least 15 carbon atoms.

[0285] The polyester materials of inventive coating 1 and comparative coating 2 were formed as follows. The diol, diacid and catalyst components listed in Table 1 were added as a batch to a vessel with a steam column, distillation head and condenser. The batch temperature is increased to 150 C. with stirring at 400 rpm under an N.sub.2 blanket. Once the temperature reaches 150 C., the batch temperature is increased to 230 C. over a 4 hour period (10 C. steps every 30 minutes), whilst ensuring that the head temperature is below 100 C.

[0286] Once the batch reaches 230 C., the acid value is assessed every hour. When the acid value is less than 15, the batch is cooled to 150 C. and methyl hydroquinone is added, then after 10 minutes, the maleic anhydride is added and the batch temperature increased to 195 C. until the acid value increases up to <20. The batch is then cooled to 130 C. and azeotropically separated using a Dean Stark trap and an addition of xylene.

[0287] The batch is then heated back up to 195 C. When the target AV and cut viscosity is reached the batch is cooled to 150 C. and the Dowanol DPM added. The batch is then held at 150 C. for 1 hour and then poured out.

[0288] The polyester materials formed then underwent a grafting process to graft acrylic onto the unsaturated functionality of the backbone of the polyester (imparted by the maleic anhydride) to form acrylic modified polyester resins 1 and 2 (noted simply as PGA resins 1 and 2 in Table 2). Details of the monomers used in the acrylic graft reaction are shown in Table 2.

[0289] The acrylic modified polyester resins were each formed as follows. Half of the amount of the polyester material given in Table 2 was added to a vessel with mixing at 225 rpm and heated to 120 C. Once at 120 C., half of total amount of each acrylic monomer as shown in Table 2 was added over a period of 40 minutes with continued stirring. 10 minutes after adding the acrylic monomers, about a third of each of the t-butyl peroctoate initiator and Dowanol DPM amounts as shown in Table 2 were added. The remaining amount of the polyester material was then added and the solution heated back to 120 C. At this stage the solution is homogeneous and has good mixing. Then the remaining acrylic monomers were added over 40 minutes. 10 minutes after adding the acrylic monomers, about a third of each of the t-butyl peroctoate initiator and Dowanol DPM amounts as shown in Table 2 were added over a 30 minute period. The remaining t-butyl peroctoate initiator and Dowanol DPM was then added in two evenly split batches, the first batch being added over 5 minutes and the mixture then held at 120 C. for 30 minutes before addition of the second batch over 5 minutes and then held at 120 C. for 30 minutes. The reaction mixture is then cooled to below 100 C.

[0290] The acrylic modified polyester resins are formed into aqueous dispersions with the components as shown in Table 3.

[0291] The acrylic modified polyester resins are formed into aqueous dispersions by heating the resin to 90 C., and during heating adding the DMEA with stirring. The mixture was then held for 10 minutes, after which deionized water was added over 60 minutes, maintaining the temperature about 85 C. The aqueous dispersions were then allowed to cool to 45 C.

[0292] The aqueous dispersions are formed into aqueous coating compositions with components as shown in Table 4, as follows. The deionized water, Dowanol PnB, crosslinking material (Cymel 1123benzoguanamine, commercially available from Allnex), and blocked DDBSA catalyst (Nacure 5925, commercially available from King) were stirred into the aqueous dispersion to form the aqueous coating composition.

TABLE-US-00001 TABLE 1 Polyesters Comparative Polyester 1 Polyester 2 Material 2-methyl-1,3-propanediol 2157.50 Cyclohexane dimethanol 924.01 TMCD Trimethylolpropane 12.62 29.24 Isophthalic acid 695.38 1117.50 Pripol 1010 (C36 Dimer Acid) 765.03 Hexahydrophthalic anhydride 619.50 Dibutyl tin oxide 2.93 Cyclohexane-1,4-dicarboxylic acid 1804.50 MeHQ 0.220 0.59 Maleic anhydride 74.44 196.90 Stannous Octoate 1.27 Xylene 118.93 705.50 Dowanol DPM 850.20 509.90 Properties Initial weight 2472.80 5928.76 Theoretical weight loss 212.01 728.01 Final resin weight 2260.79 5200.74 Total with solids 3230.09 6497.11 % solids 70.32 81.01 Mn 5,706 6,120 Mw 30,905 32,547 PDI 5.4 5.3 AV 0.45 0.70 OH 13.87 19.28

TABLE-US-00002 TABLE 2 Polyester-graft-acrylic (PGA) Resins Comparative PGA resin 1 PGA resin 2 Material Polyester 1 1,688.96 Comparative polyester 2 1,657.57 Methacrylic acid 78.8 77.88 Ethyl methacrylate 72.24 71.39 Methyl methacrylate 72.24 71.39 2-hydroxyethyl methacrylate 39.40 38.94 t-butyl peroctoate 36.9 36.88 Dowanol DPM 42.83 545.95 Properties Final % solids 59.00 59.00 % polyester 80.52 79.90 % acrylic 17.81 17.60 % initiator 1.67 2.50 AV 22.50 20.31

TABLE-US-00003 TABLE 3 Aqueous Dispersions Comp. Aq. Aq. Dispersion 1 Dispersion 2 Materials PGA resin 1 1430.00 Comparative PGA resin 2 1525.00 Dimethylethanolamine 33.25 33.08 Deionised water 1701.00 2123.55 Properties % solids 26.00 25.32 Acid Value 9.16 21 Particle size, matersizer, m 0.290 0.119

TABLE-US-00004 TABLE 4 Coating Compositions Comparative aq. Aq. Coating 1 Coating 2 Aq. dispersion 1 40.00 Comparative aq. dispersion 2 40.00 DI Water 2.31 2.73 Dowanol PnB 1.07 1.13 Cymel 1123 (benzoguanamine) 1.07 1.12 Nacure 5925 (blocked DDBSA) 0.04 0.04 Total 44.49 45.02

Testing Methods

[0293] Coated panels were obtained by drawing the aqueous coatings over a Zirconium pretreated 5182-H48 aluminum panels using a wire wound rod to obtain dry coating weights of approximately 7.0 mg/square inch (msi). The coated panels were immediately placed into a one-zone, gas-fired, conveyor oven for 10 seconds and baked to a peak metal temperature of 450 F. (232 C.).

[0294] Blush resistance measures the ability of a coating to resist attack by various testing solutions. When the coated film absorbs test solution, it generally becomes cloudy or looks white. Blush is measured visually using a scale of 1-10 where a rating of 10 indicates no blush and a rating of 0 indicates complete whitening of the film. Blush ratings of at least 7 are typically desired for commercially viable coatings. The coated panel tested is 24 inches (510 cm) and the testing solution covers half of the panel being tested so you can compare blush of the exposed panel to the unexposed portion.

[0295] Adhesion testing is performed to assess whether the coating adheres to the substrate. The adhesion test is performed according to ASTM D 3359 Test Method B, using Scotch 610 tape, available from 3M Company of Saint Paul, Minn. Adhesion is generally rated on a scale of 0-5 where a rating of 5 indicates no adhesion failure.

[0296] The Acetic Acid test is designed to measure the resistance of a coating to a boiling 3% acetic acid solution. The solution is prepared by mixing 90 grams of Glacial Acetic Acid (product of Fisher Scientific) into 3000 grams of deionized water. Coated strips are immersed into the boiling Acetic Acid solution for 30 minutes. The strips are then rinsed and cooled in deionized water, dried, and immediately rated for blush and adhesion as described previously.

[0297] The Dowfax test is designed to measure the resistance of a coating to a boiling detergent solution. The solution is prepared by mixing 5 grams of DOWFAX 2A1 (product of Dow Chemical) into 3000 grams of deionized water. Coated strips are immersed into the boiling Dowfax solution for 15 minutes. The strips are then rinsed and cooled in deionized water, dried, and immediately rated for blush and adhesion as described previously.

[0298] The Joy test is designed to measure the resistance of a coating to a hot 180 F. (82 C.) Joy detergent solution. The solution is prepared by mixing 30 grams of Ultra Joy Dishwashing Liquid (product of Procter & Gamble) into 3000 grams of deionized water. Coated strips are immersed into the 180 F. (82 C.) Joy solution for 15 minutes. The strips are then rinsed and cooled in deionized water, dried, and immediately rated for blush and adhesion as described previously.

[0299] The DI Water Retort test is designed to measure the resistance of a coating to deionized water. Coated strips are immersed into the deionized water and placed in a steam retort for 30 minutes at 250 F. (121 C.). The strips are then cooled in deionized water, dried, and immediately rated for blush and adhesion as described previously.

[0300] The 1% Citric Acid Retort test measures the resistance of a coating to 1% Citric Acid. Coated strips are immersed into the 1% citric acid solution and placed in a steam retort for 30 minutes at 250 F. (121 C.). The strips are then cooled in deionized water, dried, and immediately rated for blush and adhesion as described previously.

[0301] The results of these testing methods are provided in Table 5.

TABLE-US-00005 TABLE 5 Results 1% 1% Wedge citric citric Bends Acetic Acetic Water Water acid acid (% Acid Acid Dowfax Dowfax Joy Joy Retort Retort retort retort Coating failure)* Blush Adhesion Blush Adhesion Blush Adhesion Blush Adhesion blush adhesion Example 11 9 4B 9 5B 9 5B 9 5B 7.5 5B 1 Comp. 8 9 4B 9 5B 9 5B 9 5B 3 5B Av. Coating 1 *Results <15% are acceptable.