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, including—2,2,4,4-tetraallcylcyclobutane-1,3-diol. One of the polyacid component 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 metal packaging containing coated with the composition.

Claims

1-63. (canceled)

64. 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, including 2,2,4,4-tetraalkylcyclobutane-1,3-diol wherein one of the polyacid component 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.

65. A packaging coated on at least a portion thereof with a coating, the coating being derived from the aqueous coating composition of claim 64.

66. The coating composition according to claim 64, wherein the functional monomer comprises an ethylenically unsaturated monomer.

67. The coating composition according to claim 64, wherein the functional monomer is present as a proportion of the dry weight of the polyol or polyacid component in an amount of 0.5 to 10 wt %.

68. The coating composition according to claim 64, wherein the 2,2,4,4-tetraalkylcyclobutane-1,3-diol(TACD) is according to the structure: ##STR00017## wherein R1, R2, R3, and R4 each independently represent an alkyl radical.

69. The coating composition according to claim 64, wherein the TACD comprises 2,2,4,4-tetramethylcyclobutane-1,3-diol (“TMCD”).

70. The coating composition according to claim 64, wherein the polyol component comprises TMCD in combination with 2-methy-1,3 propanediol, cyclohexanedimethanol and/or trimethylolpropane.

71. The coating composition according to claim 64, wherein the polyester material comprises an Mn from 1,000 Daltons (Da=g/mole) to 15,000 Da.

72. The coating composition according to claim 64, wherein the polyester material has a gross OHV of from 0 to 120 mg KOH/g.

73. The coating composition according to claim 64, wherein the polyester material has an AV from 0 to 20 KOH/g.

74. The coating composition according to claim 64, wherein the crosslinking material comprises one or more of a phenolic resin, benzoguanamine or melamine.

75. The coating composition according to claim 64, wherein the aqueous coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF) and derivatives thereof.

76. The coating composition according to claim 64, wherein the aqueous coating composition further comprises an adhesion promoter.

77. The coating composition according to claim 76, wherein the adhesion promotor comprises an acidic polyester material.

78. The coating composition according to claim 77, wherein the acidic polyester 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.

79. The coating composition according to claim 64, wherein the coating composition has a solids content of from 10 to 60% by weight of the coating composition.

80. The packaging according to claim 65, wherein the packaging comprises a metal packaging container, a food or beverage can; a monobloc aerosol can; a metal cap or closure such as a bottle cap; screw top cap and lid of any size, lug cap, or the like; a plastic bottle, plastic tube, laminate or flexible packaging, such as those made from PE, PP, PET and the like.

81. The method of coating at least a portion of a packaging, the method comprising applying a coating composition of claim 64 to at least a portion of the packaging, and curing the aqueous coating composition to form a coating.

82. An electrodepositable coating composition comprising: (a) an acrylic polyester resin, 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, including 2,2,4,4-tetraalkylcyclobutane-1,3-diol wherein one of the polyacid component 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; b) a crosslinking material.

83. A powder coating composition, the powder 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, including 2,2,4,4-tetraalkylcyclobutane-1,3-diol wherein one of the polyacid component 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.

84. The coating composition of claim 64, wherein the polyacid component is substantially free of sulfonated monomer.

85. The coating composition according to claim 64, wherein neither the polyacid component nor the polyol component comprises a sulfomonomer.

86. The coating composition according to claim 64, wherein the polyester material has a hydroxyl value of 10 to 30.

87. The electrodepositable coating composition according to claim 82, wherein neither the polyacid component nor the polyol component comprises a sulfomonomer

88. The electrodepositable coating composition according to claim 82, wherein the polyester material has a hydroxyl value of 10 to 30.

89. The powder coating composition according to claim 83, wherein neither the polyacid component nor the polyol component comprises a sulfomonomer

90. The powder coating composition according to claim 83, wherein the polyester material has a hydroxyl value of 10 to 30.

Description

EXAMPLES

[0308] Actual Experimental Data—Method for the Formation of the Aqueous Coatings

[0309] The details of inventive aqueous coating 1a and 2a, and comparative aqueous coating 3a, are shown in Tables 1 to 4. Coating 1a shows unsaturated, hydroxyl functional polyesters with TMCD. Coating 2a shows unsaturated, hydroxyl functional polyesters with TMCD and a dimer fatty acid (Pripol 1010). Comparative coating 3a shows an unsaturated, hydroxyl functional polyester without TMCD.

[0310] The polyester materials of inventive coatings 1a, 2a and comparative coating 3a 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 400rpm under an N2 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.

[0311] 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.

[0312] 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.

[0313] 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 1a, 2a and 3a (noted simply as PGA resins 1a to 3a in Table 2). Details of the monomers used in the acrylic graft reaction are shown in Table 2.

[0314] 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.

[0315] The acrylic modified polyester resins are formed into aqueous dispersions with the components as shown in Table 3.

[0316] 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.

[0317] 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 1123—benzoguanamine, 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 1a Polyester 2a Polyester 3a Materials 2-methyl-1,3-propanediol 75.58 — 824.00 Cyclohexane dimethanol — 117.69 — TMCD 73.11 39.21 — Trimethylolpropane 1.82 1.88 11.24 Isophthalic acid 51.22 121.10 427.00 Pripol 1010 (C36 Dimer Acid) — 123.93 — Hexahydrophthalic anhydride 38.91 — 237.00 Dibutyl tin oxide 0.18 0.17 1.12 Cyclohexane-1,4- 110.41 — 690 dicarboxylic acid MeHQ 0.04 0.036 0.22 Maleic anhydride 12.06 10.55 75.60 Xylene 24.74 21.75 270.20 Dowanol DPM 230.51 284.40 1313.00 Properties Initial weight 361.92 414.21 2265.35 Theoretical weight loss 40.80 32.04 278.17 Final resin weight 321.13 382.17 1987.18 Total with solids 576.33 688.07 3569.27 % solids 55.72 55.54 55.67 Mn 6,160 5,412 5093 Mw 37,341 36,613 28,196 PDI 6.1 6.8 5.5 AV 4.55 1.60 2.59 OH 16.21 15.30 22.23

TABLE-US-00002 TABLE 2 Polyester-graft-acrylic (PGA) Resins Comparative PGA resin 1a PGA resin 2a PGA resin 3a Materials Polyester 1a 286.12 — — Polyester 2a — 276.66 — Comparative polyester 3a — — 599.44 Methacrylic acid 17.72 17.72 49.22 Ethyl methacrylate 16.24 16.24 45.12 Methyl methacrylate 16.24 16.24 45.12 2-hydroxyethyl 8.86 8.86 24.62 methacrylate t-butyl peroctoate 5.32 5.32 14.76 Dowanol DPM 26.58 26.58 230.86 Properties Final % solids 59.00 59.00 59.00 % polyester 70.52 70.52 70.52 % acrylic 27.81 27.81 27.81 % initiator 1.67 1.67 1.67 AV 33.51 38.04 31.40 Mn 6,305 5,771 6,643 Mw 76,799 49,237 72,059

TABLE-US-00003 TABLE 3 Aqueous Dispersions Aq. Aq. Comp. Aq. Dispersion Dispersion Dispersion 1a 2a 3a Materials PGA resin 1a 250.08 — — PGA resin 2a — 241.67 — Comparative PGA resin 3a — — 600.02 Dimethylethanolamine 9.33 9.71 19.50 Deionised water 210.11 213.80 726.00 Properties % solids 24.36 23.44 23.95 Acid Value (on 59% solids) 14.5 13.61 13.22 Particle size, matersizer, μm 0.128 26.14 12.999 Viscosity 215 77 272

TABLE-US-00004 TABLE 4 Coating Compositions Aq. Comparative Aq. Coating aq. Coating Coating 1a 2a 3a Aq. dispersion 1a 40.00 — — Aq. dispersion 2a — 40.00 — Comparative aq. dispersion 3a — — 35.00 DI Water 3.02 1.25 7.45 Dowanol PnB 1.09 1.04 0.99 Cymel 1123 (benzoguanamine) 1.08 1.04 1.48 Nacure 5925 (blocked DDBSA) 0.04 0.04 0.03 Total 45.23 43.37 44.96

Testing Methods

[0318] 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, convey or oven for 10 seconds and baked to a peak metal temperature of 450° F. (232° C.).

[0319] 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 2×4 inches (5×10 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.

[0320] 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.

[0321] 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 adhesion as described previously.

[0322] 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.

[0323] 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.

[0324] 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.

[0325] The results of these testing methods are provided in Table 5.

[0326] Aqueous dispersions produced according to the compositions of Tables 1 to 4 and the associated methods were also tested for hot room stability by exposing the dispersions to 120° F. for two weeks. The results of the hot room stability test are provided in Table 6.

TABLE-US-00005 TABLE 5 Results Acetic Water Acid Dowfax Joy Water Retort Adhe- Dowfax Adhe- Joy Adhe- Retort Adhe- Coating sion Blush sion Blush sion Blush* sion Exam- 3B 9 5B 9 5B 9 5B ple 1 Exam- 4B 9 5B 9 5B 8 5B ple 2 Comp. 3B 9 5B 9 5B 9 5B Av. Coating 1 *Any result above 7 is acceptable for a commercial coating composition

TABLE-US-00006 TABLE 6 Hot Room Stability Results Aq. dispersion Aq. dispersion Comp aq. 1a 2a dispersion 3a Particle Initial 0.122 17.184 3.898 size, μm After 2 weeks 0.122 14.468 1.087 at 120° F. % reduction  0% 16% 62% Mn Initial 6,235 5,472 6,471 After 2 weeks 4,904 4,759 5,123 at 120° F. % reduction 21% 13% 21%

Theoretical Embodiments

[0327] The details of examples 1 to 8 are shown in Table 7. Each of examples 1 to 8 shows the components of a polyester material. Examples 1 to 4 show unsaturated, hydroxyl functional polyesters with TMCD and 5-SSIPA. Examples 5 to 8 show unsaturated, hydroxyl functional polyesters with TMCD, but without 5-SSIPA.

[0328] The polyester materials of examples 1 to 8 are formed as follows. The 2-methyl-1,3 propanediol, TMCD, cyclohexanedimethanol, 5-SSIPA, dibutyl tin oxide, dimethyl terephthalate, hexahydrophthalic anhydride and cyclohexane 1,4-dicarboxylic acid are 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.

[0329] 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 to about 20. The batch is then cooled to 130 C and azeotropically separated using a Dean Stark trap.

[0330] The polyester materials of examples 1 to 8 undergo 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 to 8 (noted simply as resins 1 to 8 in Table 2). Details of the monomers used in the acrylic graft reaction are shown in Table 8.

[0331] The acrylic modified polyester resins were formed as follows. The polyester material (of Examples 1 to 8) is added to a vessel with mixing at 225 rpm and heated to 120 C. Once at 120 C, the acrylate monomers are added over a period of 75 minutes with continued stirring. Then the Dowanol DPM and t-butyl peroctoate initiator is added over a period of 90 minutes and the reaction held at 120 C for a further 45 minutes. The reaction mixture is then cooled to below 80 C.

[0332] The acrylic modified polyester resins are formed into aqueous dispersions with the components as shown in Table 9.

[0333] The acrylic modified polyester resins are formed into aqueous dispersions by heating the resin to 80 to 85 C, then slowly adding deionized water to the resins (over a period of about 60 minutes), with the elevated temperature (80 to 85 C) maintained, then stirring the dispersed mixture for a further 60 minutes at 80 to 85 C. The aqueous dispersions are then cooled.

[0334] In forming the aqueous dispersions where the polyester material does not include a sulfonated monomer, dimethylethanol amine is added to the heated (80 to 85 C) acrylic modified polyester resin and stirred for 10 minutes until homogeneous, prior to adding the deionized water. Otherwise, the process is the same.

[0335] The aqueous dispersions are formed into aqueous coating compositions with components as shown in Table 10, as follows. The crosslinking material (Cymel 1123—benzoguanamine, commercially available from Allnex), blocked DDBSA catalyst (Nacure 5925, commercially available from King) and wax additive (Michem Lube 160, commercially available from Michelman) are stirred into the water dispersed PGA dispersion to form an aqueous coating composition.

TABLE-US-00007 TABLE 7 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Material name 2-Methyl-1,3 339.50 339.50 339.50 339.50 Propanediol TMCD 542.50 542.50 542.50 542.50 542.50 542.50 542.50 542.50 Cyclohexanedimethanol 542.50 542.50 542.50 542.50 5-SSIPA 245.00 218.80 227.50 236.30 Dibutyl Tin Oxide 1.12 1.12 1.12 1.12 1.12 1.12 1.12 1.12 Dimethyl Terephthalate 385.00 678.10 332.50 647.50 564.38 835.63 503.13 822.50 Hexahydrophthalic 332.50 332.50 332.50 332.50 anhydride Cyclohexane 1,4- 612.50 656.25 612.50 656.25 dicarboxylic acid MeHQ 0.22 0.22 0.22 0.22 0.22 0.22 0.22 0.22 Maleic Anhydride 65.63 65.63 70.00 70.00 65.63 65.63 70.00 70.00 Aromatic 100 269.59 269.59 269.59 269.59 269.59 269.59 269.59 269.59 Dowanol DPM 1312.50 1312.50 1312.50 1312.50 1312.50 1312.50 1312.50 1312.50 Calculated Properties Initial weight 2191.47 2178.34 2372.59 2372.59 2125.84 2117.09 2315.72 2311.34 Theoretical water loss 211.49 176.59 211.71 171.72 244.74 205.79 243.34 204.16 Final Resin weight 1979.98 2001.75 2160.89 2200.88 1881.10 1911.31 2072.38 2107.18 Total (inc solvents) 3562.07 3583.84 3742.97 3782.96 3463.19 3493.39 3654.47 3689.27 Approx Mn 4877.00 5070.00 4939.00 5033.00 4753.00 4785.00 5090.00 5052.00 OH equivalent excess 0.81 0.79 0.88 0.88 0.79 0.80 0.81 0.83

TABLE-US-00008 TABLE 8 Resin 1 Resin 2 Resin 3 Resin 4 Resin 5 Resin 6 Resin 7 Resin 8 Polyester material of Ex. 1 453.9 Polyester material of Ex. 2 453.9 Polyester material of Ex. 3 453.9 Polyester material of Ex. 4 453.9 Polyester material of Ex. 5 453.9 Polyester material of Ex. 6 453.9 Polyester material of Ex. 7 453.9 Polyester material of Ex. 8 453.9 methacrylic acid 28.8 28.8 28.8 28.8 28.8 28.8 28.8 28.8 ethyl methacrylate 45.6 45.6 45.6 45.6 45.6 45.6 45.6 45.6 methyl methacrylate 24.1 24.1 24.1 24.1 24.1 24.1 24.1 24.1 t-butyl peroctoate 5.9 5.9 5.9 5.9 5.9 5.9 5.9 5.9 Dowanol DPM 41.8 41.8 41.8 41.8 41.8 41.8 41.8 41.8 Calculated Properties final % solids 59.00% 59.00% 59.00% 59.00% 59.00% 59.00% 59.00% 59.00% % polyester 70.52% 70.52% 70.52% 70.52% 70.52% 70.52% 70.52% 70.52% % acrylic 27.81% 27.81% 27.81% 27.81% 27.81% 27.81% 27.81% 27.81% % Initiator  1.67%  1.67%  1.67%  1.67%  1.67%  1.67%  1.67%  1.67%

TABLE-US-00009 TABLE 9 Aq. Aq. Aq. Aq. Aq. Aq. Aq. Aq. Disp 1 Disp 2 Disp 3 Disp 4 Disp 5 Disp 6 Disp 7 Disp 8 Resin 1 300 Resin 2 300 Resin 3 300 Resin 4 300 Resin 5 300 Resin 6 300 Resin 7 300 Resin 8 300 Dimethylethanolamine 11.4 11.4 11.4 11.4 Deionized Water 290 290 290 290 278.6 278.6 278.6 278.6 Calculated Properties % solids 59.00% 59.00% 59.00% 59.00% 59.00% 59.00% 59.00% 59.00% Acid Value (on 30 30 30 30 30 30 30 30 59% solids)

TABLE-US-00010 TABLE 10 Aq. Aq. Aq. Aq. Aq. Aq. Aq. Aq. Coating 1 Coating 2 Coating 3 Coating 4 Coating 5 Coating 6 Coating 7 Coating 8 Aq. Disp 1 79.5 wt % Aq. Disp 2 79.5 wt % Aq. Disp 3 79.5 wt % Aq. Disp 4 79.5 wt % Aq. Disp 5 79.5 wt % Aq. Disp 6 79.5 wt % Aq. Disp 7 79.5 wt % Aq. Disp 8 79.5 wt % Cymel 1123 20.00% 20.00% 20.00% 20.00% 20.00% 20.00% 20.00% 20.00% (benzoguanamine) Nacure 5925  0.1 wt %  0.1 wt %  0.1 wt %  0.1 wt %  0.1 wt %  0.1 wt %  0.1 wt %  0.1 wt % (blocked DDBSA) Michem Lube  0.4 wt %  0.4 wt %  0.4 wt %  0.4 wt %  0.4 wt %  0.4 wt %  0.4 wt %  0.4 wt % 160 (wax)

[0336] Certain aspects of the invention may be combined in the following combinations. [0337] 1. An acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing: [0338] i) a polyacid component, with [0339] ii) a polyol component, including [0340] 2,2,4,4-tetraallcylcyclobutane-1,3-diol [0341] wherein one of the polyacid component 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.

[0342] 2. An aqueous coating composition, the aqueous coating composition comprising: [0343] a) an acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing: [0344] i) a polyacid component, with [0345] ii) a polyol component, including [0346] 2,2,4,4-tetraallcylcyclobutane-1,3-diol [0347] wherein one of the polyacid component 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, [0348] b) a crosslinking material.

[0349] 3. A metal packaging container coated on at least a portion thereof with a coating, the coating being derived from an aqueous coating composition, the aqueous coating composition comprising: [0350] a) an acrylic polyester resin, obtainable by grafting an acrylic polymer with a polyester material, the polyester material being obtainable by polymerizing: [0351] i) a polyacid component, with [0352] ii) a polyol component, including [0353] 2,2,4,4-tetraallcylcyclobutane-1,3-diol [0354] wherein one of the polyacid component 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, [0355] b) a crosslinking material.

[0356] 4. A resin, coating composition or packaging container according to any of aspects 1 to 3, wherein the functional monomer comprises an ethylenically unsaturated monomer.

[0357] 5. A resin, coating composition or packaging container according to any of aspects 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.

[0358] 6. A resin, coating composition or packaging container according to any of aspects 1 to 5, wherein the polyacid component comprises one or more of the following: dimethyl terephthalate, isophthalic acid, hexahydrophthalic anhydride, cyclohexane 1,4-dicarboxylic acid.

[0359] 7. A resin, coating composition or packaging container according to any of aspects 1 to 6, wherein the TACD comprises 2,2,4,4-tetramethylcyclobutane-1,3-diol (“TMCD”).

[0360] 8. A resin, coating composition or packaging container according to any of aspects 1 to 7, wherein the polyol component comprises TMCD in combination with 2-methy-1,3 propanediol and/or cyclohexanedimethanol.

[0361] 9. A resin, coating composition or packaging container according to any of aspects 1 to 8, wherein the polyacid component and/or the polyol component comprises a sulfonated monomer.

[0362] 10. A resin, coating composition or packaging container according to any of aspects 1 to 9, 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.

[0363] 11. A resin, coating composition or packaging container according to any of aspects 1 to 10, wherein the polyester material comprises an Mn from 1,000 Daltons (Da=g/mole) to 15,000 Da.

[0364] 12. A resin, coating composition or packaging container according to any of aspects 1 to 11, wherein the acrylic polyester resin is formed from the polyester material and an acrylic modification polymer in a weight ratio of between 85 wt % and 55 wt % polyester material to between 45 wt % and 15 wt % acrylic modification polymer.

[0365] 13. A resin, coating composition or packaging container according to any of aspects 1 to 12, wherein an acrylic modification polymer is polymerized in the presence of the polyester material to form an acrylic modified polyester resin.

[0366] 14. A resin, coating composition or packaging container according to any of aspects 1 to 13, 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).

[0367] 15. A coating composition or packaging container according to any of aspects 1 to 14, wherein the crosslinking material may comprise one or more of a phenolic resin, benzoguanamine or melamine.

[0368] 16. A coating composition or packaging container according to any of aspects 1 to 15, wherein the aqueous coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF) and derivatives thereof.

[0369] 17. A coating composition or packaging container according to any of aspects 1 to 16, wherein the aqueous coating composition is substantially free of styrene.

[0370] 18. A coating composition or packaging container according to any of aspects 1 to 17, wherein the aqueous coating composition is substantially free of formaldehyde.

[0371] 19. A coating composition or packaging container according to any of aspects 1 to 20, wherein the aqueous coating composition further comprises an adhesion promoter.

[0372] 20. A coating composition or packaging container according to aspect 19, wherein the adhesion promotor comprises an acidic polyester material.

[0373] 21. A coating composition or packaging container according to aspect 20, wherein the acidic polyester generally comprises the reaction product of: [0374] (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: [0375] (i) a polyol component comprising a mixture of diols and triols, [0376] (ii) a polyacid component comprising an alpha, beta-ethylenically unsaturated polycarboxylic acid, [0377] and [0378] (b) a phosphorus acid.

[0379] 22. A packaging container according to any of aspects 1 to 21, wherein the packaging container comprises a food or beverage can or aerosol can.

[0380] 23. A method of forming an acrylic modified polyester resin, the method comprising polymerzing an acrylic modification polymer in the presence of a polyester material, the polyester material being obtainable by polymerizing [0381] i) a polyacid component, with [0382] ii) a polyol component, including [0383] 2,2,4,4-tetraallcylcyclobutane-1,3-diol
wherein one of the polyacid component 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.

[0384] 24. 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: [0385] i) a polyacid component, with [0386] ii) a polyol component, including [0387] 2,2,4,4-tetraallcylcyclobutane-1,3-diol [0388] wherein one of the polyacid component 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.

[0389] 25. A method of coating at least a portion of a metal packaging container, the method comprising applying an aqueous coating composition to a metal 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: [0390] i) a polyacid component, with [0391] ii) a polyol component, including [0392] 2,2,4,4-tetraallcylcyclobutane-1,3-diol
wherein one of the polyacid component 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.