Waterborne coatings

Abstract

A waterborne protective coating system is disclosed that comprises at least one binder, water, and a dispersion of 2D material/graphitic nanoplatelets.

Claims

1. A waterborne protective coating system that comprises at least one binder, water, and a dispersion of 2D material/graphitic nanoplatelets, wherein the 2D material/graphitic nanoplatelets are comprised of one or more of graphene nanoplatelets, graphitic nanoplatelets, and 2D material nanoplatelets and in which the graphene nanoplatelets are comprised of one or more of graphene nanoplates, reduced graphene oxide nanoplates, bilayer graphene nanoplates, bilayer reduced graphene oxide nanoplates, trilayer graphene nanoplates, trilayer reduced graphene oxide nanoplates, few-layer graphene nanoplates, few-layer graphene oxide nanoplates, few-layer reduced graphene oxide nanoplates, and graphene nanoplates of 6 to 10 layers of carbon atoms, and the graphitic nanoplatelets are comprised of one or more of graphite flakes with at least 10 layers of carbon atoms, graphite nanoplates with 10 to 20 layers of carbon atoms, graphite nanoplates with 10 to 14 layers of carbon atoms, graphite nanoplates with 10 to 35 layers of carbon atoms, graphite nanoplates with 10 to 40 layers of carbon atoms, graphite nanoplates with 25 to 30 layers of carbon atoms, graphite nanoplates with 25 to 35 layers of carbon atoms, graphite nanoplates with 20 to 35 layers of carbon atoms, or graphite nanoplates with 20 to 40 layers of carbon atoms, and the 2D material nanoplatelets are comprised of one or more of hexagonal boron nitride (hBN), molybdenum disulphide (MoS.sub.2), tungsten diselenide (WSe.sub.2), silicene (Si), germanene (Ge), graphyne (C), borophene (B), phosphorene (P), or a 2D in-plane or vertical heterostructure of two or more of the aforesaid materials, wherein the dispersion of 2D material/graphitic nanoplatelets comprises the 2D material/graphitic nanoplatelets, water, at least one wetting agent, and at least one grinding media, wherein the at least one grinding media is water soluble or functionalised to be water soluble, and wherein the dispersion comprises between 50 wt % and 90 wt % of the at least one grinding media.

2. A waterborne protective coating system according to claim 1 in which the 2D material/graphitic nanoplatelets further comprises at least one 1D material.

3. A waterborne protective coating system according to claim 2 in which the 1D material comprises carbon nanotubes.

4. A waterborne protective coating system according to claim 1 in which the coating system further comprises an additive, the additive comprising one of or a mixture of two or more of a dispersing additive for grinding inorganic and organic pigments in water, a defoamer, a pigment, a rheology modifier, a resin or binder, a levelling agent, a substrate wetting agent, a flow additive, a skinning preventor, or a flash rust inhibitor.

5. A waterborne protective coating system according to claim 4 in which the resin or binder of the additive is an acrylic resin or an epoxy resin.

6. A waterborne protective coating system according to claim 1 in which the at least one wetting agent comprises one of a polymeric wetting agent, an ionic wetting agent, a polymeric non-ionic dispersing and wetting agent, a cationic wetting agent, an amphoteric wetting agent, a Gemini wetting agent, a highly molecular wetting and dispersing agent or a mixture of two or more of these wetting agents.

7. A waterborne protective coating system according to claim 1 in which the at least one binder comprises one of an acrylic resin, an alkyd resin, an acrylic-alkyd hybrid resin, an epoxy resin, a polyester resin, a vinyl ester resin, a polyurethane resin, an aminoplast resin, a urethane resin, a polyamide resin, or a mixture of two or more of the aforesaid resins.

8. A waterborne protective coating system according to claim 1 in which the at least one binder comprises an acrylic-alkyd hybrid resin.

9. A waterborne protective coating system according to claim 1 in which the at least one binder comprises an epoxy resin.

10. A waterborne protective coating system according to claim 1 in which the at least one grinding media comprises an aqueous solution of a modified aldehyde resin having at least one amine group.

11. A waterborne protective coating system according to claim 1 in which the at least one grinding media is a styrene/maleic anhydride copolymer.

12. A method of formulation of a waterborne protective coating system according to claim 1 comprising the steps of (a) obtaining a liquid dispersion of 2D material/graphitic nanoplatelets, water, at least one wetting agent, and at least one grinding media in an aqueous solution, wherein the at least one grinding media is water soluble or functionalised to be water soluble, and wherein the liquid dispersion comprises between 50 wt % and 90 wt % of the at least one grinding media, and (b) mixing the liquid dispersion of 2D material/graphitic nanoplatelets with at least one binder and water; wherein the 2D material/graphitic nanoplatelets are comprised of one or more of graphene nanoplatelets, graphitic nanoplatelets, and 2D material nanoplatelets and in which the graphene nanoplatelets are comprised of one or more of graphene nanoplates, reduced graphene oxide nanoplates, bilayer graphene nanoplates, bilayer reduced graphene oxide nanoplates, trilayer graphene nanoplates, trilayer reduced graphene oxide nanoplates, few-layer graphene nanoplates, few-layer graphene oxide nanoplates, few-layer reduced graphene oxide nanoplates, and graphene nanoplates of 6 to 10 layers of carbon atoms, and the graphitic nanoplatelets are comprised of one or more of graphite flakes with at least 10 layers of carbon atoms, graphite nanoplates with 10 to 20 layers of carbon atoms, graphite nanoplates with 10 to 14 layers of carbon atoms, graphite nanoplates with 10 to 35 layers of carbon atoms, graphite nanoplates with 10 to 40 layers of carbon atoms, graphite nanoplates with 25 to 30 layers of carbon atoms, graphite nanoplates with 25 to 35 layers of carbon atoms, graphite nanoplates with 20 to 35 layers of carbon atoms, or graphite nanoplates with 20 to 40 layers of carbon atoms, and the 2D material platelets are comprised of one or more of hexagonal boron nitride (hBN), molybdenum disulphide (MoS.sub.2), tungsten diselenide (WSe.sub.2), silicene (Si), germanene (Ge), graphyne (C), borophene (B), phosphorene (P), or a 2D in-plane or vertical heterostructure of two or more of the aforesaid materials.

13. A method according to claim 12 in which the liquid dispersion of 2D material/graphitic nanoplatelets is obtained by the steps of (i) creating a dispersing medium; (ii) mixing 2D material/graphitic nanoplatelets into the dispersing medium; and (iii) subjecting the 2D material/graphitic nanoplatelets to sufficient shear forces and or crushing forces to reduce the particle size of the 2D material/graphitic nanoplatelets, wherein the mixed dispersing medium mixture comprises the 2D material/graphitic nanoplatelets, the at least one grinding media, water, and the at least one wetting agent.

14. A method according to claim 13 in which the step of subjecting the 2D material/graphitic nanoplatelets to sufficient shear forces and or crushing forces to reduce the particle size of the 2D material/graphitic nanoplatelets is performed using a grinding mill, a dissolver, a bead mill, or a three-roll mill.

15. A method according to claim 13 in which the at least one wetting agent comprises one of a polymeric wetting agent, an ionic wetting agent, a polymeric non-ionic dispersing and wetting agent, a cationic wetting agent, an amphoteric wetting agent, a Gemini wetting agent, a highly molecular wetting and dispersing agent or a mixture of two or more of these wetting agents.

16. A method according to claim 13 in which the step of creating the dispersing medium comprises mixing the at least one grinding media with the water until it is homogeneous.

17. A method according to claim 13 in which the step of creating the dispersing medium comprises mixing the at least one grinding media, water and wetting agent until the at least one grinding media, water and wetting agent mixture is homogeneous.

18. A method according to claim 17 in which the wetting agent is added to the dispersing medium at the same time as the 2D material/graphitic nanoplatelets.

19. A method according to claim 12 in which the 2D material/graphitic nanoplatelets further comprises at least one 1D material.

20. A waterborne protective coating system that comprises at least one binder, water, and a dispersion of 2D material/graphitic nanoplatelets, wherein the 2D material/graphitic nanoplatelets are comprised of one or more of graphene nanoplatelets, graphitic nanoplatelets, and 2D material nanoplatelets and in which the graphene nanoplatelets are comprised of graphene nanoplates, the graphitic nanoplatelets are comprised of graphite nanoplates with 25 to 35 layers of carbon atoms, and the 2D material nanoplatelets are comprised of one or more of hexagonal boron nitride (hBN), molybdenum disulphide (MoS.sub.2), tungsten diselenide (WSe.sub.2), silicene (Si), germanene (Ge), graphyne (C), borophene (B), phosphorene (P), or a 2D in-plane or vertical heterostructure of two or more of the aforesaid materials, wherein the dispersion of 2D material/graphitic nanoplatelets comprises the 2D material/graphitic nanoplatelets, water, at least one wetting agent, and at least one grinding media, wherein the at least one grinding media is water soluble or functionalised to be water soluble, and wherein the dispersion comprises between 50 wt % and 90 wt % of the at least one grinding media.

Description

BRIEF DESCRIPTION

(1) For a better understanding of various examples that are useful for understanding the detailed description, reference will now be made by way of example only to the accompanying drawings in which:

(2) FIG. 1 shows the different stages towards film formation;

(3) FIG. 2 shows images of test panels with coating cleaned off after Salt Spray Testing for 480 Hours ASTM B117 Neutral Salt Spray Fog Testing Results;

(4) FIG. 3 shows results of the measured corrosion average creep of coated Blasted Steel (480 hours);

(5) FIG. 4 shows results of the measured corrosion average creep of coated Bonderite Steel (480 hours);

(6) FIG. 5 shows results of the measured corrosion average creep of coated Abraded Steel (480 hours);

(7) FIG. 6 shows images of test panes with coating cleaned off after Salt Spray Testing for 1000 Hours ASTM B117 Neutral Salt Spray Fog Testing Results;

(8) FIG. 7 shows results of the measured corrosion average creep of coated Blasted Steel (1000 hours);

(9) FIG. 8 shows results of the measured corrosion average creep of coated Bonderite Steel (1000 hours); and

(10) FIG. 9 shows results of the measured corrosion average creep of coated Abraded Steel (1000 hours).

DETAILED DESCRIPTION

Examples

(11) A control sample (DTM1) and four samples of formulation according to the first aspect of the present invention (DTM2 to DTM5) were manufactured according to the formulations shown in Table 1.

(12) TABLE-US-00001 TABLE 1 Weight % of Genable ® 1250 in Formulation Sample number: 6131 9131 982 983 5% 10% 20% Genable ® Genable ® Genable ® Item Material Control 1250 1250 1250 1 Dionised Water 5.95% 5.65% 5.36% 4.76% 2 Additol VXW 1.81% 1.72% 1.63% 1.45% 6208 3 Additol VXW 0.23% 0.22% 0.21% 0.19% 6393 4 Ti-Pure R-706 25.96% 24.66% 23.36% 20.77% 5 Acrysol 0.19% 0.18% 0.17% 0.15% RM-2020E 6 Resydrol AY 60.26% 57.25% 54.24% 48.21% 6150w/45WA 7 Ammonia (29%) 0.43% 0.41% 0.39% 0.35% 8 Additol VXW 0.68% 0.64% 0.61% 0.54% 6206 9 Additol VXW 0.31% 0.29% 0.27% 0.24% 6503 N 10 Additol VXW 0.18% 0.17% 0.16% 0.15% 4973 11 Modaflow 0.50% 0.47% 0.45% 0.40% AQ-3025 12 Additol XL 297 0.54% 0.51% 0.48% 0.43% 13 Acrysol RM-8W 0.97% 0.92% 0.88% 0.78% 14 Acrysol RM 0.83% 0.79% 0.75% 0.67% 2020E 15 Dionised Water 0.17% 0.16% 0.15% 0.14% 17 Genable ™ 1250 0.00% 4.95% 9.90% 19.80% 16 HaloX Flash-X 1.00% 1.00% 1.00% 1.00% 150 Total 100.00% 100.00% 100.00% 100.00% pvc 20.08% 25.65% 30.48% 38.46% VOC (g/l) 10.43 9.91 9.38 8.34

(13) The materials shown in Table 1 are as follows: Additol VXW 6208 is a polymer non-ionic dispersing additive for grinding inorganic and organic pigments in water, Additol VXW 6393 is a defoamer, Ti-Pure R-706 is a titanium dioxide pigment, Acrysol RM2020E is a hydrophobically modified ethylene oxide urethane (HEUR) high-shear rheology modifier, Resydrol AY 6150w/45WA is an air-drying acrylic modified alkyd resin emulsion (i.e. an acrylic-alkyd hybrid resin), Additol VXW 6206 is an emulsified, nonylphenylethoxylate free combination drier of cobalt, lithium and zirconium, Additol VXW 6503 N is a levelling and substrate wetting agent based on a polyether modified polysiloxan for waterborne paint systems, Additol VXW 4973 is a defoamer, Modaflow AQ-3025 is an acrylic flow additive for aqueous coatings, Additol XL 297 is a skinning preventor, Acrysol RM-8W is a non-ionic urethane rheology modifier, and HaloX Flash-X 150 is for the inhibition of flash rust and in-can rusting in lined and unlined metal containers.

(14) Additol, Resydrol and Modaflow are trade marks of Allnex Belgium SA and the products incorporating that name are available from that company. Ti-Pure is a trade mark of The Chemours Company and the product incorporating that name is available from that company. Acrysol is a trade mark of The Dow Chemical Company and the products incorporating that name are available from that company. Halox is a trade mark of ICL Specialty Products Inc. and the product incorporating that name is available from that company.

(15) The control sample was a commercial brand water borne acrylic formulation.

(16) Manufacture followed the following steps:

(17) A pigment paste was made in a mechanical mixer:

(18) Items 1 and 2 were added to the mixer and the speed adjusted to maintain a consistent vortex (the mixer is at a medium speed). Items 1 and 3 were dispersed for 5-10 minutes.

(19) Items 3 and 4 are added and dispersed for 10 minutes at a medium—high mixer speed.

(20) Item 5 is added and dispersed for 20-30 minutes at high mixer speed to obtain a Hegman of 7+.

(21) The pigment paste is then let down in a mechanical mixer:

(22) Items 6-8 are added to a mechanical mixer and the speed adjusted to maintain a consistent vortex. Shear is applied to items 6-8 by the mixer for a minimum of 10 minutes at high speed.

(23) Items 9-12 and the pigment paste previously prepared are added to the mixer and shear is applied for a minimum of 10 minutes at low-medium speed.

(24) Items 13-15 are added and mixed for 10 minutes.

(25) Items 16-17 are added and mixed for 10 minutes

(26) Test panels were made with the characteristics shown in Table 2 and scribed in the usual fashion for testing.

(27) TABLE-US-00002 TABLE 2 Substrate Cold Rolled Carbon Steel Dimensions 150 mm by 100 mm Preparation Blasted steel (50 to 75 micron blast profile), Q-lab Bonderite steel and Q-Lab Abraded steel Application Drawdown bar Coating Thickness 110 micron wet, Dried film thickness (DET) = 50 to 60 microns Curing 7 days at 23° C.

(28) The test panels were tested to evaluate and determine if a coating system according to the present invention could deliver a meaningful extension of life relative to waterborne acrylic coatings typically used in C3 type (medium) corrosivity environments as defined in ISO 12944-2.

(29) Accelerated exposure testing was performed. The testing regime was Salt Spray Testing ASTM B117 Neutral Salt Spray Fog Testing: Corrosion Creep Assessment to ISO4628-2-2003 and ISO4628-3-2003.

(30) Images of test panels with coating cleaned off after Salt Spray Testing for 480 Hours ASTM B117 Neutral Salt Spray Fog Testing Results are shown in FIG. 2.

(31) The results of the measured corrosion average creep are as shown in FIGS. 3 to 5.

(32) It is noted that, except for the 480-hour assessment of the coated Blasted Steel control panel, all of the other control panels at both 480 hours and 1000 hours testing had substantial levels of corrosion emanating from the scribe and/or a complete failure in terms of corrosion. These panels have been denoted as having an average creep corrosion of 50 mm to aid pictorial representation in FIGS. 3 to 5 and 7 to 9.

(33) Images of test panes with coating cleaned off after Salt Spray Testing for 1000 Hours ASTM B117 Neutral Salt Spray Fog Testing Results are shown in FIG. 6.

(34) The results of the measured corrosion average creep are as shown in FIGS. 7 to 9.

(35) In the images shown of the panels in the accelerated exposure tests (ASTM B117 Neutral Salt Spray Fog Testing Results) at 480 hours and 1000 hours testing duration respectively (FIGS. 2 and 6); the graphene nanoplatelets in the acrylic formulation has reduced the corrosion observed at the scribe. The reduction in corrosion at the scribe on the test panels is the most pronounced at additions levels of Genable (trade mark) 1250 at 10% and 20% wt in the tested formulations. This performance improvement will translate into a meaningful extension of coating life for real life applications.