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

Abstract

There is described an aqueous coating composition, the aqueous coating composition comprising an acrylic polyester resin, obtainable by grafting an acrylic polymer and a polyester material, the polyester material being 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 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. The coating composition further containing a crosslinking material, wherein the crosslinking material comprises material according to formula (I); as shown in claim 1; wherein R.sub.1 is selected from aryl (such as C.sub.4 to C.sub.24 aryl), or aralkyl (such as C.sub.5 to C.sub.25 aralkyl); R.sub.2 to R.sub.5 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, are CHR.sub.8OR.sub.9.

Claims

1. 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 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, wherein the crosslinking material comprises material according to formula (I) ##STR00050## wherein R.sub.1 is selected from aryl (such as C.sub.4 to C.sub.24 aryl), or aralkyl (such as C.sub.5 to C.sub.25 aralkyl); R.sub.2 to R.sub.5 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, are CHR.sub.8OR.sub.9.

2. 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 and a polyester material, the polyester material being obtainable by polymerizing: i) a polyacid component, with ii) a polyol component, and 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, wherein the crosslinking material comprises material according to formula (I) ##STR00051## wherein R.sub.1 is selected from aryl (such as C.sub.4 to C.sub.24 aryl), or aralkyl (such as C.sub.5 to C.sub.25 aralkyl); R.sub.2 to R.sub.5 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, are CHR.sub.8OR.sub.9.

3. An aqueous coating composition, the aqueous coating composition comprising: a) an acrylic polyester resin, obtainable by grafting an acrylic polymer and 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 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, wherein the crosslinking material comprises material according to formula (II) ##STR00052## wherein R.sub.1 is selected from hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), or NR.sub.6R.sub.7; R.sub.2 to R.sub.7 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, are CHR.sub.8OR.sub.9; and wherein the coating composition is substantially free of styrene.

4. 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 and a polyester material, the polyester material being obtainable by polymerizing: i) a polyacid component, with ii) a polyol component, and 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, wherein the crosslinking material comprises material according to formula (II) ##STR00053## wherein R.sub.1 is selected from hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), or NR.sub.6R.sub.7; R.sub.2 to R.sub.7 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, are CHR.sub.8OR.sub.9; and wherein the coating composition is substantially free of styrene.

5. An aqueous coating composition, the aqueous coating composition comprising: a) an acrylic polyester resin, obtainable by grafting an acrylic polymer and a polyester material, the polyester material being obtainable by polymerizing: j) a polyacid component, with ii) a polyol component, 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, wherein the crosslinking material comprises material according to formula (II) ##STR00054## wherein R.sub.1 is selected from hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), or NR.sub.6R.sub.7; R.sub.2 to R.sub.7 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, are CHR.sub.8OR.sub.9; and wherein the coating composition is substantially free of phenolic resin.

6. 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 and a polyester material, the polyester material being obtainable by polymerizing: i) a polyacid component, with ii) a polyol component, and 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, wherein the crosslinking material comprises material according to formula (II) ##STR00055## wherein R.sub.1 is selected from hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), or NR.sub.6R.sub.7; R.sub.2 to R.sub.7 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, are CHR.sub.8OR.sub.9; and wherein the coating composition is substantially free of phenolic resin.

7. A coating composition or packaging according to any of claims 3 to 6, wherein in the crosslinking material according to formula (II), R.sub.1 is selected from C.sub.1 to C.sub.20 alkyl, C.sub.4 to C.sub.24 aryl, C.sub.5 to C.sub.25 aralkyl, or NR.sub.6R.sub.7; such as selected from C.sub.4 to C.sub.24 aryl or C.sub.5 to C.sub.25 aralkyl, or selected from C.sub.4 to C.sub.24 aryl, suitably C.sub.4 to C.sub.12 aryl, such as C.sub.6 aryl.

8. A coating composition or packaging according to any of claims 3 to 6, wherein in the crosslinking material according to formula (II), R.sub.1 is NR.sub.6R.sub.7.

9. A coating composition or packaging according to any of claims 1 to 7, wherein in the crosslinking material according to formula (I) or (II), R.sub.1 is selected from C.sub.4 to C.sub.24 aryl, or C.sub.5 to C.sub.25 aralkyl; such as selected from C.sub.4 to C.sub.24 aryl, suitably C.sub.4 to C.sub.12 aryl, such as C.sub.6 aryl.

10. A coating composition or packaging according to any of claims 1 to 9, wherein in the crosslinking material according to formula (I) or formula (II), R.sub.2 to R.sub.7, when present as applicable, are each independently hydrogen, C.sub.1 to C.sub.20 alkyl, C.sub.4 to C.sub.24 aryl or CHR.sub.8OR.sub.9; such as hydrogen, C.sub.1 to C.sub.20 alkyl or CHR.sub.8OR.sub.9, such as hydrogen, C.sub.1 to C.sub.10 alkyl or CHR.sub.8OR.sub.9; such as C.sub.1 to C.sub.5 alkyl or CHR.sub.8OR.sub.9, suitably CHR.sub.8OR.sub.9.

11. A coating composition or packaging according to any of claims 1 to 10, wherein in the crosslinking material according to formula (I) or formula (II), R.sub.2 to R.sub.7, when present as applicable, are each independently hydrogen, C.sub.1 to C.sub.20 alkyl, C.sub.4 to C.sub.24 aryl or CHR.sub.8OR.sub.9; such as hydrogen, C.sub.1 to C.sub.20 alkyl or CHR.sub.8OR.sub.9, such as hydrogen, C.sub.1 to C.sub.10 alkyl or CHR.sub.8OR.sub.9; such as C.sub.1 to C.sub.5 alkyl or CHR.sub.8OR.sub.9, suitably CHR.sub.8OR.sub.9, and R.sub.8 is independently hydrogen, C.sub.1 to C.sub.20 alkyl, C.sub.4 to C.sub.24 aryl, C.sub.5 to C.sub.25 aralkyl, alkoxyalkyl C.sub.2 to C.sub.40 alkoxyalkyl or C.sub.5 to C.sub.25 alkaryl, such as hydrogen, C.sub.1 to C.sub.20 alkyl, suitably hydrogen; and R.sub.9 is hydrogen, C.sub.1 to C.sub.20 alkyl, C.sub.4 to C.sub.24 aryl, C.sub.5 to C.sub.25 aralkyl, alkoxyalkyl C.sub.2 to C.sub.40 alkoxyalkyl or C.sub.5 to C.sub.25 alkaryl; such as hydrogen, C.sub.1 to C.sub.20 alkyl; suitably C.sub.1 to C.sub.20 alkyl, or C.sub.1 to C.sub.10 alkyl, or C.sub.1 to C.sub.5 alkyl, such as C.sub.1 or C.sub.2 alkyl.

12. A coating composition or packaging according to any of claims 1 to 11, wherein in the crosslinking material according to formula (I) or formula (II), R.sub.1 is C.sub.4 to C.sub.12 aryl, such as C.sub.6 aryl, and R.sub.2 to R.sub.7, when present as applicable, are each independently CHR.sub.8OR.sub.9, and R.sub.8 is independently C.sub.1 to C.sub.5 alkyl or hydrogen, suitably hydrogen; and R.sub.9 is C.sub.1 to C.sub.5 alkyl, such as C.sub.1 or C.sub.2 alkyl.

13. A coating composition or packaging according to any of claims 1 to 12, wherein the crosslinking material according to formula (I) or (II) is selected from one or more of melamine or derivatives thereof, such as butylated and/or methylated melamine; and/or benzoguanamine or derivatives thereof, such as butylated and/or methylated benzoguanamine, suitably, the crosslinking material according to formula (I) comprises benzoguanamine or derivatives thereof, such as butylated and/or methylated benzoguanamine.

14. A coating composition or packaging according to any of claims 1 to 13, wherein the functional monomer comprises an ethylenically unsaturated monomer.

15. A coating composition or packaging according to any of claims 1 to 14, 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.

16. A coating composition or packaging according to any of claims 1 to 15, 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 %.

17. A coating composition or packaging according to any of claims 1 to 16, 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; a monomer having an aliphatic group containing at least 15 carbon atoms; esters and anhydrides of all the aforementioned acids and combinations thereof.

18. A coating composition or packaging according to any of claims 1 to 17, 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; a monomer having an aliphatic group containing at least 15 carbon atoms.

19. A coating composition or packaging according to any of claims 1 to 18, 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.

20. A coating composition or packaging according to any of claims 1 to 19, 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; a monomer having an aliphatic group containing at least 15 carbon atoms; and the like or combinations thereof.

21. A coating composition or packaging according to any of claims 1 to 20, wherein the 2,2,4,4-tetraalkylcyclobutane-1,3-diol (TACD) is according to the structure: ##STR00056## wherein R1, R2, R3, and R4 each independently represent an alkyl radical, for example, a lower alkyl radical having 1 to 8 carbon atoms; or 1 to 6 carbon atoms, or 1 to 5 carbon atoms, or 1 to 4 carbon atoms, or 1 to 3 carbon atoms, or 1 to 2 carbon atoms, or 1 carbon atom.

22. A resin, coating composition or packaging according to any of claims 1 to 21, wherein the TACD comprises one or more of 2,2,4,4-tetramethylcyclobutane-1,3-diol (TMCD), 2,2,4,4-tetraethylcyclobutane-1,3-diol (TECD), 2,2,4,4-tetra-n-propylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-butylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-pentylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-hexylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-heptylcyclobutane-1,3-diol, 2,2,4,4-tetra-n-octylcyclobutane-1,3-diol, 2,2-dimethyl-4,4-diethylcyclobutane-1,3-diol, 2-ethyl-2,4,4-trimethylcyclobutane-1,3-diol, 2,4-dimethyl-2,4-diethyl-cyclobutane-1,3-diol, 2,4-dimethyl-2,4-di-n-propylcyclobutane-1,3-diol, 2,4-n-dibutyl-2,4-diethylcyclobutane-1,3-diol, 2,4-dimethyl-2,4-diisobutylcyclobutane-1,3-diol, and 2,4-diethyl-2,4-diisoamylcyclobutane-1,3-diol.

23. A resin, coating composition or packaging according to any of claims 1 to 22, wherein the TACD comprises 2,2,4,4-tetramethylcyclobutane-1,3-diol (TMCD).

24. A coating composition or packaging according to any of claims 1 to 23, 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.

25. A coating composition or packaging according to any of claims 1 to 24, 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 %.

26. A coating composition or packaging according to any of claims 1 to 25, 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.

27. A coating composition or packaging according to any of claims 1 to 26, wherein the polyol component comprises one or more of TMCD, 2-methy-1,3 propanediol, cyclohexanedimethanol and/or trimethylolppropane (TMP).

28. A coating composition or packaging according to any of claims 1 to 27, wherein the polyol component comprises one or more of the following: 1,4-cyclohexane dimethanol (CHDM), and trimethylolppropane (TMP).

29. A coating composition or packaging according to any of claims 1 to 28, wherein the polyacid component comprises a monomer having an aliphatic group containing at least 15 carbon atoms.

30. A coating composition or packaging according to any of claims 1 to 29, 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, from

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

32. A coating composition or packaging according to any of claims 1 to 31, wherein the aliphatic group of the aliphatic group-containing monomer is branched and/or comprises a cyclic group.

33. A coating composition or packaging according to any of claims 1 to 32, wherein aliphatic group-containing monomer is a diacid.

34. A coating composition or packaging according to any of claims 1 to 33, wherein the aliphatic group-containing monomer is a dimer fatty acid.

35. A coating composition or packaging according to any of claims 1 to 34, wherein the aliphatic group-containing monomer is the dimerisation product of erucic acid, linolenic acid, linoleic acid, stearic acid and/or oleic acid.

36. A coating composition or packaging according to any of claims 1 to 35, wherein the polyacid component and/or the polyol component comprises a sulfonated monomer.

37. A coating composition or packaging according to any of claims 1 to 36, 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.

38. A coating composition or packaging according to any of claims 1 to 37, 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.

39. A coating composition or packaging according to any of claims 1 to 38, 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.

40. A coating composition or packaging according to any of claims 1 to 39, 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 mg KOH/g or even less than 3 mg KOH/g.

41. A coating composition or packaging according to any of claims 1 to 40, 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.

42. A coating composition or packaging according to any of claims 1 to 41, 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.

43. A coating composition or packaging according to any of claims 1 to 42, 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.

44. A coating composition or packaging according to any of claims 1 to 43, wherein an acrylic modification polymer is polymerized in the presence of the polyester material to form an acrylic modified polyester resin.

45. A coating composition or packaging according to any of claims 1 to 44, 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).

46. A coating composition or packaging according to any of claims 1 to 45, wherein the acrylic monomers comprises a hydroxyl functional monomer, such as hydroxyethyl (meth)acrylate.

47. A coating composition or packaging according to any of claims 1 to 46, 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 %.

48. A coating composition or packaging according to any of claims 1 to 47, 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).

49. A resin, coating composition or packaging according to any of claims 1 to 48, 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.

50. A resin, coating composition or packaging according to any of claims 1 to 49, 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.

51. A coating composition or packaging according to any of claims 1 to 50, 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.

52. A coating composition or packaging according to any of claims 1 to 51, 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.

53. A coating composition or packaging according to any of claims 1 to 52, 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.

54. A coating composition or packaging according to any of claims 1 to 53, 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.

55. A coating composition or packaging according to any of claims 1 to 54, wherein the aqueous coating compositions comprises from 0.5 to 40 wt %, suitably from 1 to 30 wt %, such as from 5 to 20 wt % of the crosslinking material based on the total solid weight of the aqueous coating composition.

56. A coating composition or packaging according to any of claims 1 to 55, wherein the crosslinking material according to formula (I) or formula (II) forms at least 50 wt % of the crosslinking material of the coating composition, such as at least 60 wt %, at least 70 wt %, at least 80 wt %,

57. A coating composition or packaging according to any of claims 1 to 56, wherein the crosslinking material according to formula (I) or formula (II) forms at least 90 wt %, at least 95 wt % or at least 98 wt % such as at least 99 wt % of the crosslinking material of the coating composition.

58. A coating composition or packaging according to any of claims 1 to 57, wherein the aqueous coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF) and derivatives thereof.

59. A coating composition or packaging according to any of claims 1 to 58, wherein the aqueous coating composition is substantially free of styrene.

60. A coating composition or packaging according to any of claims 1 to 59, wherein the aqueous coating composition is substantially free of formaldehyde.

61. A coating composition or packaging according to any of claims 1 to 60, wherein the aqueous coating composition further comprises an adhesion promoter.

62. A coating composition or packaging according to claim 61, wherein the adhesion promotor comprises an acidic polyester material.

63. A coating composition or packaging according to claim 62, 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.

64. A coating composition according to any of claims 1 to 63, 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 %.

65. A packaging according to any of claims 1 to 64, wherein the packaging comprises a food or beverage can or aerosol can.

66. 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 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, wherein the crosslinking material comprises material according to formula (I) ##STR00057## wherein R.sub.1 is selected from aryl (such as C.sub.4 to C.sub.24 aryl), or aralkyl (such as C.sub.5 to C.sub.25 aralkyl); R.sub.2 to R.sub.5 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, are CHR.sub.8OR.sub.9.

67. 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 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, wherein the crosslinking material comprises material according to formula (II) ##STR00058## wherein R.sub.1 is selected from hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), or NR.sub.6R.sub.7; R.sub.2 to R.sub.7 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, are CHR.sub.8OR.sub.9; and wherein the coating composition is substantially free of styrene.

68. 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, and 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, wherein the crosslinking material comprises material according to formula (II) ##STR00059## wherein R.sub.1 is selected from hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), or NR.sub.6R.sub.7; R.sub.2 to R.sub.7 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, are CHR.sub.8OR.sub.9; and wherein the coating composition is substantially free of phenolic resin.

69. 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, and 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, wherein the crosslinking material comprises material according to formula (II) ##STR00060## wherein R.sub.1 is selected from hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), or NR.sub.6R.sub.7; R.sub.2 to R.sub.7 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, are CHR.sub.8OR.sub.9; and curing the aqueous coating composition to form a coating.

70. 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, and 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, wherein the crosslinking material comprises material according to formula (II) ##STR00061## wherein R.sub.1 is selected from hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), or NR.sub.6R.sub.7; R.sub.2 to R.sub.7 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, are CHR.sub.8OR.sub.9; wherein the coating composition is substantially free of styrene and curing the aqueous coating composition to form a coating.

71. 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, and 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, wherein the crosslinking material comprises material according to formula (II) ##STR00062## wherein R.sub.1 is selected from hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), or NR.sub.6R.sub.7; R.sub.2 to R.sub.7 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl) or CHR.sub.8OR.sub.9; wherein R.sub.8 and R.sub.9 are each independently hydrogen, alkyl (such as C.sub.1 to C.sub.20 alkyl), aryl (such as C.sub.4 to C.sub.24 aryl), aralkyl (such as C.sub.5 to C.sub.25 aralkyl), alkoxyalkyl (such as C.sub.2 to C.sub.40 alkoxyalkyl) or an alkaryl (such as C.sub.5 to C.sub.25 alkaryl); wherein at least one of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, is CHR.sub.8OR.sub.9, suitably all of R.sub.2 to R.sub.5, or R.sub.2 to R.sub.7 when present, are CHR.sub.8OR.sub.9; wherein the coating composition is substantially free of phenolic resin and curing the aqueous coating composition to form a coating.

72. A packaging or method according to any of claims 1 to 68, wherein the packaging is metal packaging, such as a metal can.

Description

EXAMPLES

Method for the Formation of the Aqueous Coatings

[0462] The details of inventive aqueous coating compositions 1 to 3 and comparative aqueous coating composition 4 are shown in Tables 1 to 4. Coating compositions 1 to 4 show a composition containing a polyester-graft-acrylic (PGA) and a guanamine or melamine based crosslinking material. Comparative coating composition 4 shows a polyester-graft-acrylic and a phenolic resin crosslinking material.

[0463] The polyester material used in coating compositions 1 to 4 was 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.

[0464] 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.

[0465] 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.

[0466] The polyester material 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 (noted simply as PGA resin 1 in Table 2). Details of the monomers used in the acrylic graft reaction are shown in Table 2.

[0467] The acrylic modified polyester resins were each formed as follows. Half of the amount of the polyester material given in Table 2 was added with 187.78 g of the butyl cellosolve to a vessel with mixing at 350 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 20.30 g of the butyl cellosolve and with continued stirring. 10 minutes after adding the acrylic monomers, about a third of the t-butyl peroctoate initiator amount as shown in Table 2 and 17.90 g of the butyl cellosolve 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 with 20.30 g of the butyl cellosolve. 10 minutes after adding the acrylic monomers, about a third of each of the t-butyl peroctoate initiator amount as shown in Table 2 and 17.98 g of the butyl cellosolve were added over a 30 minute period. The remaining t-butyl peroctoate initiator was then added in two evenly split batches, each batch with 11.98 g of the butyl cellosolve. The first batch was 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 80 C.

[0468] The acrylic modified polyester resins are formed into aqueous dispersions with the components as shown in Table 3.

[0469] 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. The aqueous dispersions were then allowed to cool to 45 C.

[0470] 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 and blocked DDBSA catalyst were stirred into the aqueous dispersion to form the aqueous coating composition.

TABLE-US-00001 TABLE 1 Polyester Polyester 1 Material Cyclohexane dimethanol 767.00 Trimethylolpropane 10.40 Isophthalic acid 567.70 Pripol 1010 (C36 Dimer Acid) 634.00 MeHQ 0.18 Maleic anhydride 61.30 Stannous Octoate 1.00 Xylene 98.20 Dowanol DPM 713.00 Properties Initial weight 2036.34 Theoretical water loss 173.53 Final resin weight 1862.81 Total with solids 2673.98 % solids 67.14 Mn 5,651 Mw 25,403 PDI 4.50 AV 1.57 OH 15.6

TABLE-US-00002 TABLE 2 Polyester-graft-acrylic (PGA) Resin PGA resin 1 Material Polyester 1 850.74 Methacrylic acid 67.66 Ethyl methacrylate 62.02 Methyl methacrylate 62.02 2-hydroxyethyl methacrylate 33.83 t-butyl peroctoate 20.43 Butyl cellosolve 288.30 Properties Final % solids 58.19 % polyester 69.90 % acrylic 27.60 % initiator 2.50 AV 31.84 Mn 5,289 Mw 33,328

TABLE-US-00003 TABLE 3 Aqueous Dispersions Aq. Dispersion 1 Materials PGA resin 1 625.00 Dimethylethanolamine 20.97 Deionised water 869.41 Properties % solids 23.91 Acid Value 13.59 Particle size, matersizer, m 0.432

TABLE-US-00004 TABLE 4 Coating Compositions Compar- ative Exam- Exam- Exam- Exam- Material Description ple 1 ple 2 ple 3 ple 4 Aq. polyester 40.00 40.00 40.00 40.00 Dispersion 1 grafted acrylic resin DI Water de-ionized 4.05 4.09 4.09 2.48 water Dowanol solvent 1.13 1.13 1.13 1.09 PnB.sup.1 Cymel 1123.sup.2 benzoguanamine 1.69 1.04 Cymel 1130.sup.3 methylated/ 1.69 butylated melamine Cymel 303.sup.4 methylated 1.69 melamine HRJ-13078.sup.5 phenolic resin 1.74 Nacure blocked catalyst 0.04 0.04 0.04 0.04 5925.sup.6 Total 46.91 46.94 46.94 45.39 .sup.1available from Dow Chemical .sup.2-4available from Allnex .sup.5available from King

Testing Methods

[0471] 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.).

[0472] The coatings were evaluated for the number of double rubs by hand it took to soften and break through the coating with a rag saturated with methyl ethyl ketone. Their flexibility was evaluated with a wedge bend test. For this test, coated panels were cut into 2 inch by 4.5 inch pieces, with the substrate grain running perpendicular to the long length of the cut panel. They were then bent over a % inch metal dowel along the long length of the panel with the coated side facing out. The bent coupons were then placed onto a block of metal where a wedge was pre-cut out of it with a taper of 0 to % inch along a 4.5 inch length. Once placed in the wedge, each bent coupon was struck with a block of metal which weighed 2.1 kilograms from a height of 11 inches to form a wedge where one end of the coated metal impinged upon itself and a % inch space remained on the opposite end. The wedge bent panels were then placed into an aqueous solution of copper sulfate and hydrochloric acid for two minutes to purposely etch the aluminum panel in areas where the coatings failed and cracked. The etched wedge bent panels were then examined through a microscope at 10 power to determine how far from the impinged end along the bent radii did the coating crack. Flex results are reported as the percentage of cracked area versus total length of the wedge bent panel. The coatings were also evaluated for their ability to adhere to the aluminum panels and to resist blushing in four aqueous solutions.

[0473] 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.

[0474] 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.

[0475] 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.

[0476] 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.

[0477] 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.

[0478] 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.

[0479] The results of these testing methods are provided in Table 5.

TABLE-US-00005 TABLE 5 Results Wedge Acetic Acetic Water Water MEK Bends (% Acid Acid Dowfax Dowfax Joy Retort Retort Coating rubs failure) Blush Adhesion Blush Adhesion Joy Blush Adhesion Blush Adhesion Example 1 100 14 8 4B 9 5B 9 5B 9 5B Example 2 100 23 7 0B 9 5B 9 5B 9 5B Example 3 100 21 7 0B 9 5B 9 5B 8 5B Comparative 2 31 2 0B 6 5B 7 5B 6 5B example 4