Powder coating composition

Abstract

A powder coating composition grindable at non-cryogenic temperatures includes: (a) a first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; (b) a second polymer having a Tm of at least 100 C.; and optionally (c) a cross-linker. The first polymer and the second polymer are different from one another, and each of the first and second polymers have less than 25 wt % fluorine-containing monomeric units, with wt % based on the total weight of the monomeric units in each polymer. Upon grinding at a temperature above 4 C. the coating composition has an average particle size from 15 to 150 microns. Further coating compositions, methods of preparing coating compositions, coating systems, and substrates coated with a powder coating composition are also disclosed.

Claims

1. A powder coating composition grindable at non-cryogenic temperatures comprising: (a) a first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; (b) a second polymer having a Tm of at least 100 C.; and (c) a cross-linker, wherein the first polymer and the second polymer are different from one another and each of the first and second polymers have less than 25 wt % fluorine-containing monomeric units, with wt % based on the total weight of the monomeric units in each polymer; and wherein upon grinding at a temperature above 4 C. the coating composition has an average particle size from 15 to 150 microns, wherein the first polymer comprises a thermoset polymer and the second polymer comprises a thermoplastic polymer.

2. The powder coating composition of claim 1, wherein the first polymer comprises a polyester having carboxylic acid groups, the second polymer comprises a polyamide and/or a polyethylene, and the cross-linker comprises a non-triglycidyl isocyanurate (TGIC) cross-linker reactive with the carboxylic acid groups of the first polymer.

3. The powder coating composition of claim 1, wherein the first polymer comprises a thermoset polyester and the second polymer comprises a thermoplastic polyester.

4. The powder coating composition of claim 3, wherein the cross-linker comprises hydroxyalkyamide and/or oxazoline.

5. A method of preparing a powder coating composition according to claim 1 comprising: (i) mixing together to produce a polymer mixture: (a) a first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; (b) a second polymer different from the first polymer, wherein the second polymer has a Tm of at least 100 C.; wherein each of the first polymer and the second polymer have less than 25 wt % fluorine-containing monomeric units, with wt % based on the total weight of the monomeric units, wherein the first polymer comprises a thermoset polymer and the second polymer comprises a thermoplastic polymer; and (c) a cross-linker, wherein the polymer mixture of (i) is grindable at a temperature above 4 C. to form a powder coating composition having an average particle size from 15 to 150 microns; and (ii) grinding the polymer mixture of (i) to form the powder coating composition having an average particle size from 15 to 150 microns.

6. The method of claim 5, wherein the polymer mixture comprises a polymer dispersion comprising the first polymer, the second polymer, and a medium, wherein the medium is removed before step (ii).

7. The method of claim 5, wherein the polymer mixture is a dry mixture comprising the first polymer and the second polymer, wherein the dry mixture is extruded to produce particulates of the polymer mixture before step (ii).

8. A coating system comprising: an undercoat; and an overcoat coating composition comprising the powder coating composition of claim 1.

9. A substrate at least partially coated with the powder coating composition of claim 1.

10. The substrate of claim 9, wherein the substrate comprises a vehicle.

11. The substrate of claim 9, wherein the substrate comprises a package.

12. The substrate of claim 11, wherein the package comprises a metal can, an aerosol can or tube, or a monobloc aerosol can or tube.

13. A coil spring at least partially coated with the powder coating composition of claim 2.

14. A powder coating composition grindable at non-cryogenic temperatures comprising: (a) a first non-polyester polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; (b) a second polymer having a Tm of at least 100 C.; and (c) a cross-linker reactive with the first polymer, wherein the first polymer and the second polymer are different from one another and each of the first and second polymers have less than 25 wt % fluorine-containing monomeric units, with wt % based on the total weight of the monomeric units in each polymer; and wherein upon grinding at a temperature above 4 C. the coating composition has an average particle size from 15 to 150 microns, wherein the first polymer comprises a thermoset polymer and the second polymer comprises a thermoplastic polymer.

15. The powder coating composition of claim 14, wherein the first polymer comprises a carboxylic acid group and/or a hydroxyl group, and the cross-linker is reactive with the carboxylic acid group and/or the hydroxyl group of the first polymer.

16. The powder coating composition of claim 14, wherein: the first polymer comprises an acrylic resin; and the second polymer comprises poly(vinyl chloride).

17. The powder coating composition of claim 14, wherein: the first polymer comprises an acrylic resin; and the second polymer comprises a polyolefin.

18. The powder coating composition of claim 17, wherein the cross-linker comprises a hydroxyalkyamide cross-linker.

19. The powder coating composition of claim 14, wherein: the first polymer comprises an acrylic resin or a polyamide wax; and the second polymer comprises a polyamide.

20. The powder coating composition of claim 14, wherein: the first polymer comprises an acrylic resin; and the second polymer comprises a thermoplastic acrylic resin, polyamide, polyolefin and/or polyester.

21. A method of preparing a powder coating composition according to claim 14 comprising: (i) mixing together to produce a polymer mixture: (a) a non-polyester first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; (b) a second polymer different from the first polymer, wherein the second polymer has a Tm of at least 100 C.; and (c) a cross-linker reactive with the first polymer, wherein each of the first polymer and the second polymer have less than 25 wt % fluorine-containing monomeric units, with wt % based on the total weight of the monomeric units, wherein the first polymer comprises a thermoset polymer and the second polymer comprises a thermoplastic polymer, wherein the polymer mixture of (i) is grindable at a temperature above 4 C. to form a powder coating composition having an average particle size from 15 to 150 microns; and (ii) grinding the polymer mixture of (i) to form the powder coating composition having an average particle size from 15 to 150 microns.

22. The method of claim 21, wherein the polymer mixture comprises a polymer dispersion comprising the first polymer the second polymer, and a medium, wherein the medium is removed before step (ii).

23. The method of claim 21, wherein the polymer mixture is a dry mixture comprising the first polymer and the second polymer, wherein the dry mixture is extruded to produce particulates of the polymer mixture before step (ii).

24. A coating system comprising: an undercoat; and an overcoat coating composition comprising the powder coating composition of claim 14.

25. A substrate at least partially coated with the powder coating composition of claim 14.

26. The substrate of claim 25, wherein the substrate comprises a vehicle.

27. The substrate of claim 25, wherein the substrate comprises a package.

28. The substrate of claim 27, wherein the package comprises a metal can, an aerosol can or tube, or a monobloc aerosol can or tube.

29. A powder coating composition grindable at non-cryogenic temperatures comprising: (a) a first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; (b) a second polymer comprising poly(vinyl chloride), the second polymer having a Tm of at least 100 C.; and (c) a cross-linker reactive with the first polymer, wherein the first polymer and the second polymer are different from one another; wherein upon grinding at a temperature above 4 C. the coating composition has an average particle size from 15 to 150 microns; and wherein the first polymer comprises a thermoset polymer and the second polymer comprises a thermoplastic polymer.

30. The powder coating composition of claim 29, wherein, the first polymer comprises a polyester.

31. A method of preparing a powder coating composition according to claim 29 comprising: (i) mixing together to produce a polymer mixture: (a) a first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; (b) a second polymer comprising poly(vinyl chloride), the second polymer having a Tm of at least 100 C.; and (c) a cross-linker reactive with the first polymer, wherein the polymer mixture of (i) is grindable at a temperature above 4 C. to form a powder coating composition having an average particle size from 15 to 150 microns, wherein the first polymer comprises a thermoset polymer and the second polymer comprises a thermoplastic polymer; and (ii) grinding the polymer mixture of (i) to form the powder coating composition having an average particle size from 15 to 150 microns.

32. The method of claim 31, wherein the polymer mixture comprises a polymer dispersion comprising the first polymer the second polymer, and a medium, wherein the medium is removed before step (ii).

33. The method of claim 31, wherein the polymer mixture is a dry mixture comprising the first polymer and the second polymer, wherein the dry mixture is extruded to produce particulates of the polymer mixture before step (ii).

34. A coating system comprising: an undercoat; and an overcoat coating composition comprising the powder coating composition of claim 29.

35. A substrate at least partially coated with the powder coating composition of claim 29.

36. The substrate of claim 35, wherein the substrate comprises a vehicle.

37. The substrate of claim 35, wherein the substrate comprises a package.

38. The substrate of claim 37, wherein the package comprises a metal can, an aerosol can or tube, or a monobloc aerosol can or tube.

Description

EXAMPLES

(1) The following examples are presented to demonstrate the general principles of the invention. The invention should not be considered as limited to the specific examples presented.

Examples 1-2

Preparation of Nylon Containing Dispersion Powder Coating Compositions

(2) Powder coating compositions containing polyamide were prepared from the components listed in Table 1.

(3) TABLE-US-00001 TABLE 1 Component Example 1 Example 2 Acrylic Dispersion.sup.1 15.8 g 5.2 g ME27720.sup.2 5.2 g 15.7 g GRILTEX D 1428A.sup.3 62.8 g 62.7 g Benzoin.sup.4 0.5 g 0.5 g PL-200.sup.5 0.5 g 0.5 g TINUVIN 144.sup.6 0.2 g 0.2 g TINUVIN 405.sup.7 0.2 g 0.2 g TIONA 121.sup.8 15.0 g 15.0 g .sup.1An aqueous dispersion of an acrylic polymer produced from a monomer mixture of 74% methyl methacrylate, 22% ethyl acrylate, and 4% methacrylic acid (Mn = 2005 and Tg = 69 C.) .sup.2A polyamide wax dispersion in water commercially available from Michelman Inc. (Blue Ash, OH) (Tm = 115 C., as measured by the supplier) .sup.3A free flowing nylon powder commercially available from EMS Group (Domat/Ems, Switzerland) (Tm = 175 C., as measured by the supplier) .sup.4Benzoin, commercially available from Mitsubishi Chemical Corporation (Tokyo, Japan) .sup.5Acrylic/silica flow and leveling control agent, commercially available from Estron Chemical Inc. (Calvert City, KY) .sup.6A UV stabilizer commercially available from BASF (Ludwigshafen, Germany) .sup.7A UV stabilizer commercially available from BASF (Ludwigshafen, Germany) .sup.8Titanium Dioxide pigment commercially available from Fitz Chem Corporation (Itasca, IL)

(4) The water containing components were weighed and placed into a container along with 0.1 g of water defoamer BYK-011 (from BYK-Chemie GMBH (Wesel, Germany)). All components except the GRILTEX D 1428A were added to the water containing components slowly under high agitation with a cowles blade. The mixture was then moved to a Hockmeyer bead mill (Model #SHM-MM-4829) and milled at 3,000 rpm for ten minutes. The GRILTEX D 1428A was then dispersed into the mixture using a cowles blade on high shear for 5 minutes.

(5) The mixture's water was then evaporated using heat, leaving a solid material. The mixture's water was evaporated and the mixture dried using the following procedure. A Sussman Electric Boiler (Model #MBA18) drum dryer (Sussman Electric Boliers (Long Island City, N.Y.)) was connected to a Yaskawa Varispeed V7-4X speed controller (Yaskawa America (Waukegan, Ill.)) whose speed was programmed to 60 rpm drum speed. The drums were heated with steam at a pressure of 10 to 30 psi creating a temperature of 100 C. to 150 C. at the nip point between the two drums. The nip displacement was set to 1 mm or wider. The mixture was poured slowly into the area between the drums allowing for the boiling and evaporation of the water. The remaining solid material adhered to the drum where it passed through the nip and was scraped off by stationary razor blades pressed against the drum.

(6) The dried mixture was milled in a Mikro ACM-1 Air Classifying Mill (Hosokawa Micron Powder Systems (Summit, N.J.)) at ambient temperature (25 C.) to obtain a particle size range of 0.4 to 100 microns, with the average particle size being 35 microns. The particle size was determined by running the powder through a Beckman Coulter LS 13 320 Laser diffraction particle size analyzer (Beckman Coulter Inc. (Brea, Calif.)) to determine the volume average particle size. This was done by placing the powder in a cell, which is placed into the particle sizer. The vacuum nozzle's geometry created a vortex in which the powder is drawn upwards through the instrument. A laser in the instrument then diffracted depending on the particle size distribution. A readout on the computer program (LS 13320 SW) was then displayed on the screen. The curve begins at 0 microns particle size and estimates upwards of 1000 microns. Analysis of the distribution curve can provide the average particle size which may be a strong indicator of how the finished powder will behave.

(7) The resulting coating compositions for each of the Examples 1 and 2 were solid particulate powder coating compositions that were free flowing.

Examples 3-4

Preparation of PVC Containing Dry Powder Coating Compositions

(8) Powder coating compositions containing PVC were prepared from the components listed in Table 2.

(9) TABLE-US-00002 TABLE 2 Component Example 3 Example 4 Dispersion PVC.sup.9 80.1 g 72 g Pentaerythritol Tetrabenzoate.sup.10 70.2 g 61 g Epoxy Resin.sup.11 5.8 g 4.8 g Benzoin.sup.4 1.6 g 1.4 g PL200.sup.5 1.6 g 1.4 g Zn Stearate 3.1 g 2.8 g Barium Stearate 3.1 g 2.8 g TINUVIN 144.sup.6 1.6 g 1.4 g TINUVIN 405.sup.7 1.6 g 1.4 g Titanium Dioxide.sup.12 22.5 g 40 g Polyester resin.sup.13 25 g 0 g Polycaprolactone.sup.14 0 g 10.8 g TOTAL 216.2 g 199.8 g .sup.9A polyvinyl chloride homopolymer resin commercially available from Formosa Plastics Corp (Taiwan) (Tm = 226 C.) .sup.10A benzoate based plasticizer and a phthalate based plasticizer commercially available from Lanxess Aktiengesellschaft (Cologne, Germany) .sup.11An epoxy resin having epoxy functional groups, hydroxyl functional groups and an equivalent weight of 525 to 550, commercially available from Hexion Inc. (Columbus, OH) .sup.12Titanium Dioxide pigment commercially available from Fitz Chem Corporation (Itasca, IL) .sup.13A polyester resin produced from a monomer mixture of 60% polyethylene terephthalate flakes, 12.1% terephthalic acid, 12.1% isophthalic acid, 3% adipic acid, 9.3% neopentyl glycol, 3.5% trimethylolpropane (Mn = 2673, Tg = 61 C.) .sup.14Capa 6500 polycaprolactone sold by Perstop (Malm, Sweden) (Mn = 23000 and Tg = 60 C., as measured by the supplier)

(10) The coating compositions were extruded and then milled (as in Examples 1-2) at ambient temperature (25 C.) to obtain a particle size range (as measured in Examples 1-2) of 5 to 100 microns and an average particle size of 25 microns.

(11) The resulting coating compositions for the Examples 3 and 4 were solid particulate powder coating compositions that were free flowing.

Examples 5-9

Preparation of Dispersion Powder Coating Compositions

(12) Powder coating compositions containing polyamide were prepared from the components listed in Table 3.

(13) TABLE-US-00003 TABLE 3 Component Example 5 Example 6 Acrylic Dispersion.sup.1 18.3 g 18.3 g Deionized Water 116.4 g 97.4 g VESTOSINT 2157.sup.15 94.0 g 0 g RILSAN D50 Nat.sup.16 0 g 94 g Titanium Dioxide.sup.17 20.0 g 20 g RESIFLOW PL-200a.sup.18 1.0 g 1.0 g .sup.15Polyamide 12 powder from Evonik Industries (Essen, Germany) (Tm = 184 C., as measured by the supplier) .sup.16Polyamide 11 powder from Evonik Industries (Essen, Germany) (Tm = 186 C., as measured by the supplier) .sup.17TIOXIDE TR-93 from Huntsman Corporation (The Woodlands, TX) .sup.18Flow and leveling control agent from Estron Chemical Inc. (Calvert City, KY)

(14) Powder coating compositions containing polyolefin were prepared from the components listed in Table 4.

(15) TABLE-US-00004 TABLE 4 Component Example 7 Example 8 Acrylic Dispersion.sup.1 73.3 g 146.52 g CANVERA 1110.sup.19 176.3 g 131.7 g Titanium Dioxide.sup.17 30 g 30 g RESIFLOW PL-200a.sup.18 1.0 g 1.0 g .sup.19Polyolefin dispersion from Dow Chemical Company (Midland, MI) (Tm = 127 C.)

(16) A powder coating composition containing polyester was prepared from the components listed in Table 5.

(17) TABLE-US-00005 TABLE 5 Component Example 9 Acrylic Dispersion.sup.1 55.0 g GRILTEX D1377D.sup.20 82.0 g Titanium Dioxide.sup.17 25.0 g BLANC FIXE MICRO.sup.21 10.0 g Micro Mica W1.sup.22 5.0 g BYK-3900P.sup.23 1.0 g BYK-3950P.sup.24 1.0 g CERAFLOUR 961.sup.25 1.0 g .sup.20Thermoplastic polyester from EMS Group (Domat/Ems, Switzerland) (Tm = 155 C., as measured by the supplier) .sup.21BLANC FIXE MICRO from Sachtleben Chemie (Duisburg, Germany) .sup.22Micro Mica from Omya (Oftringen, Switzerland) .sup.23Anti-cratering additive from BYK-Chemie GMBH (Wesel, Germany) .sup.24Leveling additive from BYK-Chemie GMBH (Wesel, Germany) .sup.25Degassing additive from BYK-Chemie GMBH (Wesel, Germany)

(18) In the preparation of Examples 5-9, the liquid containing components were weighed and placed into a container and then the powder materials were added to the liquid components slowly under agitation with a cowles blade. The mixture was then mixed for 15 minutes under high shear using a cowles blade. The mixture's water was then evaporated using heat, leaving a solid material (using the method described in Examples 1-2). The material was milled (as described in Examples 1-2) using a Mikro ACM-1 Air Classifying Mill at 20 C. to obtain a particle size range of 5 to 80 microns and an average particle size of 31 microns (as measured in Examples 1-2).

(19) The resulting coating compositions for each of the Examples 5-9 were solid particulate powder coating compositions that were free flowing.

(20) The powder coating compositions of Examples 5-9 were electrostatically sprayed on electrolytic tinplated steel using a Nordson Versa Spray II electrostatic sprayer (Nordson Corporation (Amherst, Ohio)). The powder coating composition was applied at a thickness of 50 to 110 microns. The powder coating composition was heated in a one-zone, gas-fired, conveyor oven for 20 seconds and baked to a peak metal temperature of 250 C. to form a coating.

(21) Various characteristics of the resulting coatings of Examples 5-9 are shown in Table 6.

(22) TABLE-US-00006 TABLE 6 Test Example 5 Example 6 Example 7 Example 8 Example 9 MEK 100 100 100 100 100 Resistance Cross-hatch 4B 4B 5B 5B 5B Adhesion Wedge Bend 68 mm 58 mm 45 mm 55 mm 45 mm Test 20 in-lb No Crack No Crack No Crack No Crack No Crack Direct Impact Deionized 0B 0B 5B 5B 5B Water Retort

(23) The MEK double rub test rub used a gauze covered hammer that was saturated with methyl ethyl ketone. The coatings of Examples 5-9 were evaluated for the number of double rubs it took to soften and break through the coating or reached 100 double rubs.

(24) The cross-hatch adhesion testing was performed to assess whether the coating adhered to the substrate. The adhesion test was performed according to ASTM D 3359 Test Method B, using Scotch 610 tape, available from 3M Company (Maplewood, Minn.)

(25) The wedge bend test included bending a coated test specimen over a 3 mm mandrel to form a test wedge. The test wedge was then impacted along the deformation axis with a 2.4 kg weight dropped from a height of 60 cm. The millimeters of coating failure along the deformation axis of the test wedge is reported.

(26) The 20 in-lb direct impact test was used to determine resistance to cracking caused by direct impact and was measured in accordance with ASTM D2794.

(27) Deionized Water Retort was designed to measure the resistance of a coating to deionized water. Coated strips were immersed into the deionized water and placed in a steam retort for 30 minutes at 250 F. (121 C.). The strips were then cooled in deionized water, dried, and immediately rated for adhesion as described previously.

Examples 10-13

Preparation of Dry Powder Coating Compositions

(28) A powder coating composition containing thermoplastic polyester and acrylic was prepared from the components listed in Table 7.

(29) TABLE-US-00007 TABLE 7 Component Example 10 GRILTEX D1377E.sup.26 67.0 g DEGALAN LP67/11.sup.27 30.0 g Titanium Dioxide.sup.17 25.0 g BLANC FIXE MICRO.sup.21 10.0 g Micro Mica W1.sup.22 5.0 g BYK-3900P.sup.23 1.0 g BYK-3950P.sup.24 1.0 g CERAFLOUR 961.sup.25 1.0 g .sup.26Thermoplastic polyester having a Tg of 25 C. and a Tm of 150 C.-160 C. from EMS Group (Domat/Ems, Switzerland), as measured by the supplier .sup.27Acrylic resin from Evonik Industries (Essen, Germany) (Mw = 37,000 and Tg = 85 C., as measured by the supplier)

(30) Powder coating compositions containing polyester were prepared from the components listed in Table 8.

(31) TABLE-US-00008 TABLE 8 Example Example Comparative Component 11 12 Example 13 GRILTEX D1377E.sup.26 57.0 g 55.0 g 97 g Thermoset Polyester.sup.28 40.0 g 40.0 g 0 g Titanium Dioxide.sup.17 25.0 g 25.0 g 25.0 g BLANC FIXE MICRO.sup.21 10.0 g 10.0 g 10.0 g Micro Mica W1.sup.22 5.0 g 5.0 g 5.0 g BYK-3900P.sup.23 1.0 g 1.0 g 1.0 g BYK-3950P.sup.24 1.0 g 1.0 g 1.0 g CERAFLOUR 961.sup.25 1.0 g 1.0 g 1.0 g PRIMID QM-1260.sup.29 0 g 2.0 g 0 g .sup.28An acid functional polyester resin having an acid value of 33 and a Tg of 55 C. prepared from a reaction mixture of 40% terepthalic acid, 3% adipic acid, 19.5% isophthalic acid, 37.5% neopentyl glycol (Mn = 4218) .sup.29Hydroxyalkylamide crosslinker from EMS Group (Domat/Ems, Switzerland)

(32) Examples 10-12 were prepared using the components and amounts (parts by weight in grams) shown in Tables 7 and 8. The coating compositions were prepared by premixing the ingredients in a three-blade mixer rotating at 3500 rpm. The premix was then extruded in a 19 mm dual screw extruder operating at a temperature of 110 C. The extrudate was rapidly cooled and pressed into a chip. The addition of 0.3% AEROSIL 200 from Evonik Industries (Essen, Germany) was added to the chip prior to milling. The chip was micronized to a particle size of 20-50 microns (as measured in Examples 1-2) using a Mikro ACM-1 Air Classifying Mill (as described in Examples 1-2) at 20 C. The average particle size for Example 10 was 27.5 microns (as described in Examples 1-2). The average particle size for Example 11 was 27.8 microns (as described in Examples 1-2). The average particle size for Example 12 was 27.73 microns (as described in Examples 1-2).

(33) Comparative Example 13 was prepared using the components and amounts (parts by weight in grams) shown in Table 8. The coating composition was prepared by premixing the ingredients in a three-blade mixer rotating at 3500 rpm. The premix was then extruded in a 19 mm dual screw extruder operating at a temperature of 110 C. The extrudate was rapidly cooled, but could not be pressed into a chip due to the lack of brittleness of the material at ambient conditions. Since the extrudate could not be pressed into chip form, it was not grindable.

(34) The powder coating compositions were electrostatically sprayed on electrolytic tinplated steel using a Nordson Versa Spray II electrostatic sprayer (Nordson Corporation (Amherst, Ohio)). The powder coating compositions were applied at a thickness of 50 to 110 microns. The powder coated panels were heated in a one-zone, gas-fired, conveyor oven for 15 seconds to obtain a peak metal temperature of 260 C. to form a coating.

(35) Various characteristics of the resulting coatings of Examples 10-12 are shown in Table 9. The tests performed on Examples 10-12 are identical to those performed on Examples 5-9, previously described.

(36) TABLE-US-00009 TABLE 9 Test Example 10 Example 11 Example 12 MEK Resistance 100 100 100 Cross-hatch 5B 5B 5B Adhesion Wedge Bend Test 14 mm 85 mm 9 mm 20 in-lb Direct No Crack Slight Crack No Crack Impact Deionized Water 5B 3B 5B Retort

(37) The present invention further includes the subject matter of the following clauses: Clause 1: A powder coating composition comprising: (a) a first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; (b) a second polymer having a Tm of at least 100 C.; and (c) a cross-linker, wherein the first polymer and the second polymer are different from one another and each of the first and second polymers have less than 25 wt % fluorine-containing monomeric units, with wt % based on the total weight of the monomer units in each polymer having an average particle size from 15 to 150 microns.

(38) Clause 2: A powder coating composition comprising: (a) a first non-polyester polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; and (b) a second polymer having a Tm of at least 100 C., wherein the first polymer and the second polymer are different from one another and each of the first and second polymers have less than 25 wt % fluorine-containing monomeric units, with wt % based on the total weight of the monomer units in each polymer and having an average particle size from 15 to 150 microns.

(39) Clause 3: A powder coating composition comprising: (a) a first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; and (b) a second polymer comprising poly(vinyl chloride), the second polymer having a Tm of at least 100 C., wherein the first polymer and the second polymer are different from one another, and having an average particle size from 15 to 150 microns.

(40) Clause 4: The powder coating composition of clause 2, wherein the first polymer is cross-linkable and the composition further comprises a cross-linker.

(41) Clause 5: The powder coating composition of clause 2 or 4, wherein the first polymer comprises an acrylic resin, and the second polymer comprises poly(vinyl chloride).

(42) Clause 6: The powder coating composition of clause 3, wherein the first polymer comprises a polyester.

(43) Clause 7: The powder coating composition of clause 2 or 4, wherein the first polymer comprises an acrylic resin, and the second polymer comprises a polyolefin.

(44) Clause 8: The powder coating composition of clause 7, further comprising a hydroxyalkyamide cross-linker.

(45) Clause 9: The powder coating composition of clause 1, wherein the first polymer comprises a polyester having carboxylic acid groups, the second polymer comprises a polyamide and/or a polyethylene, and the cross-linker comprises a non-triglycidyl isocyanurate (TGIC) cross-linker reactive with the carboxylic acid groups of the first polymer.

(46) Clause 10: The powder coating composition of clause 2 or 4, wherein the first polymer comprises an acrylic resin or a polyamide wax, and the second polymer comprises a polyamide.

(47) Clause 11: The powder coating composition of clause 2 or 4, wherein the first polymer comprises an acrylic resin, and the second polymer comprises a thermoplastic acrylic resin, polyamide, polyolefin and/or polyester.

(48) Clause 12: The powder coating composition of clause 1, wherein the first polymer comprises a thermoset polyester and the second polymer comprises a thermoplastic polyester.

(49) Clause 13: The powder coating composition of clause 12, wherein the cross-linker comprises hydroxyalkyamide or oxazoline.

(50) Clause 14: A method of preparing a powder coating composition comprising: (i) mixing together to produce a polymer mixture: (a) a first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; (b) a second polymer different from the first polymer, wherein the second polymer has a Tm of at least 100 C.; wherein each of the first polymer and the second polymer have less than 25 wt % fluorine-containing monomeric units, with wt % based on the total weight of the monomer units; and (c) a cross-linker, and (ii) grinding the polymer mixture of (i) to form the powder coating composition having an average particle size from 15 to 150 microns.

(51) Clause 15: A method of preparing a powder coating composition comprising: (i) mixing together to produce a polymer mixture: (a) a non-polyester first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; and (b) a second polymer different from the first polymer, wherein the second polymer has a Tm of at least 100 C., wherein each of the first polymer and the second polymer have less than 25 wt % fluorine-containing monomeric units, with wt % based on the total weight of the monomer units; and (ii) grinding the polymer mixture of (i) to form the powder coating composition having an average particle size from 15 to 150 microns.

(52) Clause 16: A method of preparing a powder coating composition comprising: (i) mixing together to produce a polymer mixture: (a) a first polymer having a number average molecular weight (Mn) of more than 1,000 and a Tg of at least 40 C.; and (b) a second polymer comprising poly(vinyl chloride), the second polymer having a Tm of at least 100 C., wherein the second polymer has a Tm of at least 100 C.; and (ii) grinding the polymer mixture of (i) to form the powder coating composition having an average particle size from 15 to 150 microns.

(53) Clause 17: The method of any of clauses 14-16, wherein the polymer mixture comprises a polymer dispersion comprising the first polymer the second polymer, the crosslinker if present, and a medium, wherein the medium is removed before step (ii).

(54) Clause 18: The method of any of clauses 14-16, wherein the polymer mixture is a dry mixture comprising the first polymer, the second polymer, and the crosslinker if present wherein the dry mixture is extruded to produce particulates of the polymer mixture before step (ii).

(55) Clause 19: The method of any of clauses 14-18, wherein the polymer mixture is ground at a temperature above 4 C.

(56) Clause 20: A coating system comprising: an undercoat; and an overcoat coating composition comprising the powder coating composition of any of clauses 1-13.

(57) Clause 21: A substrate at least partially coated with the powder coating composition of any of clauses 1-13.

(58) Clause 22: The substrate of clause 21, wherein the substrate comprises a vehicle.

(59) Clause 23: A package at least partially coated with the powder coating composition of clause 7, 8, 10, or 12.

(60) Clause 24: A package at least partially coated with the powder coating composition of clause 11.

(61) Clause 25: The package of clause 23 or 24, wherein the package comprises a metal can, an aerosol can or tube, or a monobloc aerosol can or tube.

(62) Clause 26: The package of clause 24, wherein the package comprises a metal can, and the powder coating composition is applied to a side stripe of the metal can.

(63) Clause 27: A coil spring at least partially coated with the powder coating composition of clause 9.

(64) Clause 28: The powder coating composition of any of clauses 1-13, wherein the second polymer has a Tg of at least 40 C.

(65) Clause 29: The powder coating composition of any of clauses 1-13 or 28, wherein the first polymer has a number average molecular weight (Mn) of no more than 5,000.

(66) Clause 30: The powder coating composition of any of clauses 1-13, 28 or 29, wherein the coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE), and triglycidyl isocyanurate (TGIC).

(67) Clause 31: The powder coating composition of any of clauses 1-13 or 28-30, wherein the second polymer has a number average molecular weight (Mn) of at least 5,000.

(68) Clause 32: The powder coating composition of any of clauses 1-13 or 28-31, wherein the first polymer and the second polymer are present in the powder coating composition in a weight range of 1:1 to 1:2.

(69) Clause 33: The powder coating composition of clause 1 or 4, wherein the cross-linker comprises a cross-linker reactive with the first polymer having carboxylic acid groups, or a hydroxyl-reactive cross-linker reactive with the first polymer having hydroxyl groups, or a mixture thereof.

(70) Clause 34: The powder coating composition of any of clauses 1-13 or 28-33, wherein the first polymer is water dispersible.

(71) Clause 35: The powder coating composition of any of clauses 1-13 or 28-34, wherein the second polymer comprises a poly(vinyl chloride), a polyethylene, a polyamide, a polyolefin, a polyester, a co-polyester, a polyimide, a polyurethane, or a mixture thereof.

(72) Clause 36: The powder coating composition of any of clauses 1-13 or 28-35, wherein the first polymer comprises an acrylic, a polyamide wax, a polyester, polyester grafted acrylic, a polyurethane, or a mixture thereof.

(73) Clause 37: The powder coating composition of any of clauses 1-13 or 28-36, wherein the first polymer is present in the powder coating composition in an amount of from 5 percent by weight to 95 percent by weight, based on total solids weight of the first polymer and the second polymer, and the second polymer is present in the powder coating composition in an amount of from 5 percent by weight to 95 percent by weight, based on total solids weight of the first polymer and the second polymer.

(74) Clause 38: The powder coating composition of any of clauses 1-13 or 28-37, further comprising at least one of a color pigment, an extender pigment, and/or a filler.

(75) Clause 39: The powder coating composition of any of clauses 1-13 or 28-38, wherein the first polymer has a Tg of at least 45 C.

(76) Clause 40: The powder coating composition of any of clauses 1-13 or 28-39, wherein the first polymer has a Tg of at least 60 C.

(77) Clause 41: The powder coating composition of any of clauses 1-13 or 28-40, wherein the first polymer acts as a plasticizer in the coating composition.

(78) Clause 42: The powder coating composition of any of clauses 1-13 or 28-41, wherein the average particle size ranges from 15-50 microns, or from 20-45 microns, or from 25-40 microns, or from 30-35 microns, or from 15-75 microns, or from 15-80 microns, or from 15-90 microns, or from 15-100 microns, or from 15-110 microns, or from 15-120 microns, or from 15-130 microns, or from 15-140 microns.

(79) Clause 43: The powder coating composition of any of clauses 1-13 or 28-42, wherein the first polymer has a number average molecular weight (Mn) of more than 2,000.

(80) Clause 44: The powder coating composition of any of clauses 1-13 or 28-43, wherein the second polymer has a Tg of 40 C. to 90 C., or 35 C. to 80 C., or 25 C. to 70 C., or 15 C. to 60 C., or 5 C. to 50 C., or 0 C. to 40 C.

(81) Clause 45: The powder coating composition of clause 33, wherein the cross-linker comprises hydroxyalkyamide, hydroxyalkylurea, carbodiimide, oxazoline, or a mixture thereof.

(82) Clause 46: The powder coating composition of any of clauses 1-13 or 28-45, wherein the second polymer is present in the powder coating composition in an amount greater than 20 percent by weight, or greater than 25 percent by weight, or greater than 30 percent by weight, or greater than 35 percent by weight, or greater than 40 percent by weight, or greater than 45 percent by weight, or greater than 50 percent by weight, or greater than 55 percent by weight, or greater than 60 percent by weight, or greater than 65 percent by weight, or greater than 70 percent by weight, based on total solids weight of the first polymer and the second polymer.

(83) Clause 47: The powder coating composition of any of clauses 1-13 or 28-46, wherein the first polymer is acid functional.

(84) Clause 48: The powder coating composition of clause 33, wherein the hydroxyl-reactive cross-linker comprises a blocked isocyanate resin, melamine, an aminoplast, or a mixture thereof.

(85) Clause 49: The powder coating composition of any of clauses 1-13 or 28-48, wherein the first polymer has a number average molecular weight (Mn) from 1,000 to 7,000.

(86) Clause 50: The powder coating composition of any of clauses 1-13 or 28-49, wherein the first polymer has a number average molecular weight (Mn) from 1,000 to 5,000.

(87) Clause 51: The powder coating composition of any of clauses 1-13 or 28-50, wherein the first polymer has a number average molecular weight (Mn) of no more than 4,000.

(88) Clause 52: The powder coating composition of any of clauses 1-13 or 28-51, wherein the first polymer has a weight average molecular weight (Mw) of no more than 15,000.

(89) Clause 53: The powder coating composition of any of clauses 1-13 or 28-52, wherein the first polymer has a weight average molecular weight (Mw) of no more than 12,000.

(90) Clause 54: The powder coating composition of any of clauses 1-13 or 28-53, wherein the first polymer has a weight average molecular weight (Mw) of no more than 10,000.

(91) Clause 55: The powder coating composition of any of clauses 1-13 or 28-54, wherein the first polymer has a weight average molecular weight (Mw) of no more than 8,000.

(92) Clause 56: The coating system of clause 20, wherein the undercoat comprises: a polyester material and benzoguanamine or a derivative thereof.

(93) Clause 57: The coating system of any of clauses 20 or 56, wherein the coating system is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE), and triglycidyl isocyanurate (TGIC).

(94) Clause 58: The coating system of any of clauses 20, 56, or 57, wherein the undercoat, when cured, has a flexibility of at least 20 mm as measured according to the draw and re-draw test method with processing in 1% salt (NaCl) solution in tap water at 130 C. for 60 minutes and a scratch resistance of at least 700 g as measured according to ISO Standard 1518-1:2011.

(95) Clause 59: The coating system of any of clauses 20 or 56-58, wherein the undercoat comprises at least 1 wt % of benzoguanamine or a derivative thereof based on the total solid weight of the coating composition.

(96) Clause 60: The coating system of any of clauses 20 or 56-59, wherein the undercoat comprises at least 4.5 wt % of benzoguanamine or a derivative thereof based on the total solid weight of the coating composition.

(97) Clause 61: The method of clause 17, wherein the polymer dispersion is dried by spray drying, tray drying, freeze drying, fluid bed drying, single or double drum drying, flash drying, swirl drying, and/or microwave drying.

(98) Clause 62: The package of any of clauses 23-26, wherein the package is coated on at least a portion thereof with the powder coating composition, wherein the powder coating composition is substantially free of bisphenol A (BPA), bisphenol F (BPF), bisphenol A diglycidyl ether (BADGE), bisphenol F diglycidyl ether (BFDGE), and triglycidyl isocyanurate (TGIC).

(99) Clause 63: A powder coating composition comprising: (a) a first polymer grindable above 4 C. by itself; and (b) a second polymer not grindable above 4 C. by itself, wherein the first polymer and the second polymer are different from one another and each of the first and second polymers have less than 25 wt % fluorine-containing monomeric units, with wt % based on the total weight of the monomer units in each polymer, and wherein, upon grinding at a temperature above 4 C., the coating composition has an average particle size from 15 to 150 microns.

(100) Clause 64: The substrate of any of clauses 21, wherein the substrate comprises a package.

(101) Clause 65: The substrate of clause 59, wherein the package comprises a metal can, an aerosol can or tube, or a monobloc aerosol can or tube

(102) Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims.