MX2015004080A - Electrically conductive coatings containing graphenic carbon particles. - Google Patents

Abstract

Coating compositions containing graphenic carbon particles are disclosed. The graphenic carbon particles may be thermally produced and dispersed in thermoset and/or thermoset polymeric film coatings. The cured coatings exhibit desirable properties such as increased electrical conductivity.

Description

COATINGS ELECTRICALLY CONDUCTORS CONTAINING GRAPHIC CARBON PARTICLES Field of the Invention

[0002] The present invention relates to electrically conductive coatings containing graphene carbon particles.

Background of the Invention

[0003] Many different types of coating are subjected to environments where electrical conductivity is desired. For example, the improved conductivity properties can be advantageous for different types of transparent coatings, color coatings, primer coatings, static dissipative coatings and electrical thermal coatings, printed electronics, batteries, capacitors, electrical traces, antennas and similar.

Brief Description of the Invention

[0004] One aspect of the invention provides an electrically conductive coating composition comprising a film-forming resin and thermally produced graphite carbon particles. When the coating composition is cured it has a higher electrical conductivity than an electrical conductivity of the same coating composition without the carbon particles thermally produced graphically.

[0005] Another aspect of the invention provides an electrically conductive coating comprising a film of polymeric resin and thermally produced graphite carbon particles dispersed in the polymeric resin film.

[0006] A further aspect of the invention provides a method of manufacturing an electrically conductive coating composition comprising mixing thermally produced graphite carbon particles with a film-forming resin.

Brief Description of the Figures

[0007] Figure 1 is a graph illustrating electrical conductivity properties of different coatings containing thermally produced graphite carbon particles according to embodiments of the present invention as compared to coatings containing other types of commercial graphene particles.

[0008] Figure 2 is a graph illustrating electrical conductivity properties of different coatings containing a type of commercially available graphite carbon particles together with either thermally produced graphite carbon particles of the present invention or other types of carbon particles. commercially available graphene.

Detailed description of the invention

[0009] In accordance with the embodiments of the present invention, graphene carbon particles are added to coating compositions to provide desirable properties such as increased electrical conductivity. As used herein, the term "electrically conductive", when referring to a coating containing graphene carbon particles, means that the coating has an electrical conductivity of at least 0.001 S / m. For example, the coating may have a conductivity of at least 0.01, or at least 10 S / m. Conventionally the conductivity can be from 100 to 100,000 S / m, or more. In certain embodiments, the conductivity can be at least 1,000 S / m or at least 10,000 S / m. For example, the conductivity for being at least 20,000 S / m, or at least 30,000 S / m, or at least 40,000 S / m. [00010] According to certain embodiments, the coatings do not exhibit significant electrical conductivity in the absence of the addition of graphene carbon particles. For example, a conventional topcoat may have a conductivity that is not measurable, while coatings of the present invention that include graphene carbon particles may exhibit conductivities as noted above. In certain embodiments, the addition of graphene carbon particles increases the conductivity of coatings by more than a factor of 10, conventionally more than a factor of 1,000 or 100,000 or more. [00011] In certain embodiments, the graphene carbon particles can be added to the film-forming resins in amounts of 0.1 to 95 percent by weight based on the total coating solids. For example, graphene carbon particles may comprise from 1 to 90 weight percent, or from 5 to 85 weight percent. In certain embodiments, the amount of graphene carbon particles contained in the coatings can be relatively large, such as from 40 to 50 weight percent up to 90 or 95 weight percent. For example, graphene carbon particles may comprise from 60 to 85 weight percent, or from 70 to 80 weight percent. In certain embodiments, the conductivity properties of the coatings can be increased significantly with relatively minor additions of the graphite carbon particles, for example, less than 50 weight percent, or less than 30 weight percent. In certain embodiments, the present coatings have sufficiently high electrical conductivities at relatively low charges of the graphite carbon particles. For example, the electrical conductivities noted above can be achieved in particle loads of graphene carbon of less than 20 to 15 weight percent. In certain embodiments, the particle loads may be less than 10 to 8 weight percent, or less than 6 or 5 weight percent. For example, for coatings comprising polymers or film-forming resins which by themselves are non-conductive, the addition of 3 to 5 weight percent of the thermally produced graphite carbon particles can provide an electrical conductivity of at least .01 S / m, for example, or at least 10 S / m. [00012] The coating compositions may comprise any of a variety of thermoplastic and / or thermosetting compositions known in the art. For example, the coating compositions may comprise film-forming resins selected from epoxy resins, acrylic polymers, polyester polymers, polyurethane polymers, polyamide polymers, polyether polymers, bisphenol A-based epoxy polymers, polysiloxane polymers, styrenes, ethylenes, butylenes, copolymers thereof, and mixtures thereof. In general, these polymers can be any polymer of these types produced by any method known to those skilled in the art. These polymers may be solvent-based, water-soluble or dispersible, emulsifiable, or water-limited solubility. In addition, polymers can be provided in sol-gel systems, they can provide in capsid polymer systems, or they can be provided in powder form. In certain embodiments, the polymers are dispersions in a continuous phase comprising water and / or organic solvent, for example emulsion polymers or non-aqueous dispersions. [00013] Thermosettable or curable coating compositions conventionally comprise polymers or film-forming resins having functional groups that are reactive with either themselves or with a crosslinking agent. The functional groups in the film-forming resin can be selected from any of a variety of reactive functional groups including, for example, carboxylic acid groups, amine groups, epoxide groups, hydroxyl groups, thiol groups, carbamate groups, amide groups, urea groups, isocyanate groups (including blocked isocyanate groups and tris-alkylcarbamoyltriazine) mercaptan groups, sterinetic groups, anhydrous groups, acetoacetate acrylates, uretidione and combinations thereof. [00014] Thermosetting coating compositions conventionally comprise a crosslinking agent which can be selected from, for example, aminoplasts, polyisocyanates including blocked isocyanates, polyepoxides, beta-hydroxyalkylamides, polyacids, anhydrides, acid-functional materials organometallics, polyamines, polyamides, and mixtures of any of the foregoing. Suitable polyisocyanates include multifunctional isocyanates. Examples of multifunctional polyisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate, and aromatic diisocyanates such as toluene diisocyanate and 4,40-diphenylmethane diisocyanate. The polyisocyanates can be blocked or unblocked. Examples of other suitable polyisocyanates include isocyanurate trimers, allophanates, and uretdiones of diisocyanates. Examples of commercially available polyisocyanates include DESMODUR N3390, which is sold by Bayer Corporation, and TOLONATE HDT90, which is sold by Rhodia Inc. Suitable aminoplasts include condensates of amines and amides with aldehyde. For example, the condensate of melanin with formaldehyde is a suitable aminoplast. Suitable aminoplasts are well known in the art. A suitable aminoplast is described, for example, in U.S. Patent No. 6,316,119 in column 5, lines 45-55, incorporated by reference herein. In certain embodiments, the resin can be self-crosslinking. Self-crosslinking means that the resin contains functional groups that are capable of reacting with themselves, such as alkoxysilane groups, or that the product of the reaction contains functional groups that are active-active, example, hydroxyl groups and blocked isocyanate groups. [00015] The dry film thickness of the cured coatings can conventionally vary from less than 0.5 microns to 100 microns or more, for example, from 1 to 50 microns. As a particular example, the cured coating thickness can vary from 1 to 15 microns. [00016] According to certain embodiments, when the coating compositions are cured, the resulting coatings comprise a continuous matrix of the resin cured with graphene carbon particles dispersed therein. The graphene carbon particles can be dispersed uniformly throughout the thickness of the coating. Alternatively, the graphene carbon particles can be distributed unevenly, for example, with a particle distribution gradient across the thickness of the coating and / or through the coating. [00017] As used herein, the term "graphene carbon particles" refers to carbon particles having structures comprising one or more layers of flat sheets of one atom thick of sp2 carbon atoms attached that are densely packed. grouped in a honeycomb crystal lattice. The average number of stacked layers can be less than 100, for example, less than 50. In certain embodiments, the average number of stacked layers is 30 or less, such as 20 or less, 10 or less, or, in some cases, 5 or less. The graphene carbon particles may be substantially flat, however, at least a portion of the flat sheets may be substantially curved, wavy, creased or buckled. The particles conventionally do not have a spheroidal or equiaxial morphology. [00018] In certain embodiments, the graphene carbon particles present in the coating compositions of the present invention have a thickness, measured in a direction perpendicular to the carbon atom layers, of not more than 10 nanometers, not more than 5 nanometers. nanometers, or, in certain embodiments, no more than 4 or 3 or 2 nanometers, such as no more than 3.6 nanometers. In certain embodiments, the graphene carbon particles can be 1 layer thickness of an atom up to 3, 6, 9, 12, 20 or 30 atoms, or more. In certain embodiments, the graphene carbon particles present in the compositions of the present invention have average particle sizes, i.e., widths and lengths, measured in a direction parallel to the layers of carbon atoms, of at least 10 or 30 nanometers , such as less than 50 nanometers, in some cases more than 100 nanometers up to 1,000 nanometers. For example, the average particle size of the graphene carbon particles can be 200 to 800 nm, or 250 to 750 nm. The graphene carbon particles can be provided in the form of ultra-thin flakes, platelets or sheets having relatively high average aspect ratios (the aspect ratio that is defined as the ratio of the longest dimension of a particle to the shortest dimension of the particle) of more than 3: 1, such as more than 10: 1 to 2000 :1. For example, aspect ratios may be greater than 15: 1, or greater than 25: 1, or greater than 100: 1, or greater than 500: 1. [00019] In certain embodiments, the graphene carbon particles used in the coating compositions of the present invention have a relatively low oxygen content. For example, the graphene carbon particles used in certain embodiments of the compositions of the present invention can, even when they have a thickness of not more than 5 or not more than 2 nanometers, have an oxygen content of not more than 2 percent in atomic weight, such as not more than 1.5 or 1 percent by atomic weight, or not more than 0.6 percent by atomic weight, such as about 0.5 percent by atomic weight. The oxygen content of the graphene carbon particles can be determined using x-ray photoelectron spectroscopy, as described in D. R. Drcyeret al., Chem. Soc. Rev.39, 228-240 (2010). [00020] In certain embodiments, the graphene carbon particles used in the coating compositions of the present invention have a specific surface area B.E.T. of at least 50 square meters per gram, such as at least 70 square meters per gram, or, in some cases, at least 100 square meters per gram. For example, the surface area can be 100 or 150 to 500 or 1,000 square meters per gram, or 150 to 300 or 400 square meters per gram. In certain embodiments, the surface area is less than 300 square meters per gram, for example, less than 250 square meters per gram. As used herein, the term "specific surface area B.E.T." refers to a specific surface area determined by nitrogen adsorption according to the ASTMD 3663-78 standard based on the Brunauer-Em ett-Teller method described in "The Journal of the American Chemical Society", 60, 309 (1938). [00021] In certain embodiments, the graphene carbon particles used in the coating compositions of the present invention have a Raman 2D / G peak spectroscopy ratio of at least 1.1, for example, at least 1.2 or 1.3. As used herein, the term "peak ratio 2D / G" refers to the ratio of the intensity of the 2D peak to 2692 crrf1 to the peak G intensity at 1580 cm ~ 1. [00022] In certain embodiments, the graphene carbon particles used in the coating compositions of the present invention have a bulk density. relatively low For example, the graphene carbon particles used in certain embodiments of the present invention are characterized in that they have a bulk density (bulk density) of less than 0.2 g / cm 3, such as not more than 0.1 g / cm 3. For the purposes of the present invention, the apparent density of the graphene carbon particles is determined by placing 0.4 grams of the graphene carbon particles in a glass specimen having a readable scale. The specimen rises approximately one inch and is struck 100 times, by striking the base of the specimen on a hard surface, to allow the graphene carbon particles to settle within the specimen. Then the volume of the particles is measured, and the bulk density is calculated by dividing 0.4 grams by the measured volume, where the bulk density is expressed in terms of g / cm3. [00023] In certain embodiments, the graphene carbon particles used in the coating compositions of the present invention have a compressed density and a percentage densification that is less than the compressed density and percentage densification of the graphite powder and certain types of particles. of substantially flat graphene carbon. The lower compressed density and the lower percentage densification is believed to each contribute to better dispersion and / or properties rheological particles that exhibit greater compressed density and higher percentage densification. In certain embodiments, the compressed density of the graphene carbon particles is 0.9 or less, such as less than 0.8, less than 0.7, such as 0.6 to 0.7. In certain embodiments, the percent densification of the graphene carbon particles is less than 40 percent, such as less than 30 percent, such as 25 to 30 percent. [00024] For purposes of the present invention, the compressed density of the graphene carbon particles is calculated from a measured thickness of a given mass of the particles after compression. Specifically, the measured thickness is determined by subjecting 0.1 grams of the graphene carbon particles to cold pressing under 15,000 pounds of force in a 1.3-centimeter die for 45 minutes, where the contact pressure is 500 MPa. The compressed density of the graphene carbon particles is then calculated from this thickness measured according to the following equation: Compressed density (g / cm3) = 0.1 grams p * (1.3cm / 2) (thickness measured in cm) [00025] Then the percentage densification of the graphene carbon particles is determined as the ratio of the calculated compressed density of the graphene carbon particles, as determined above, at 2.2 g / cm 3, which is the density of the graphite. [00026] In certain embodiments, the graphene carbon particles have a measured liquid conductivity of at least 10 micro-Siemens, such as at least 30 micro-Siemens, such as at least 100 micro-Siemens immediately after mixing and in later points in time, such as 10 minutes, or 20 minutes, or 30 minutes, or 40 minutes. For the purposes of the present invention, the apparent liquid conductivity of the graphene carbon particles is determined as follows. First, a sample comprising a solution of 0.5% graphite carbon particles in butyl cellosolve for 30 minutes with an ultrasound bath is added. Immediately after the ultrasound bath, the sample is placed in a normal calibrated electrolytic conductivity cell (K = l). A Scientific AB 30 conductivity meter is introduced into the sample to measure the conductivity of the sample. The conductivity is plotted over the course of approximately 40 minutes. [00027] According to certain embodiments, percolation, defined as long-range interconnectivity, occurs between conductive graphene carbon particles. This percolation can reduce the resistivity of the coating compositions. The conductive graphene carbon particles can occupy a minimum volume within the coating in such a way that the particles form a continuous, or almost continuous, network. In this case, the aspect ratios of the graphene carbon particles can affect the minimum volume required for percolation. In addition, the surface energy of the graphene carbon particles can be the same or similar to the surface energy of the elastomeric rubber. Otherwise, the particles may tend to flocculate or separate as they are processed. [00028] The thermally produced graphite carbon particles used in the coating compositions of the present invention are manufactured by thermal processes. In accordance with embodiments of the invention, thermally produced graphite carbon particles are made of carbon containing precursor materials that are heated at high temperatures in a thermal zone such as a plasma. As described more fully below, the carbon containing precursor materials are heated to a sufficiently high temperature, eg, above 3500 ° C, to produce graphite carbon particles having characteristics as described above. The precursor containing carbon, such as a hydrocarbon provided in gaseous form or liquid, it is heated in the thermal zone to produce the graphene carbon particles in the thermal zone or current below it. For example, thermally produced graphite carbon particles can be manufactured by the systems and methods described in U.S. Patent Nos. 8,486,363 and 8,486,364. [00029] In certain embodiments, thermally produced graphite carbon particles can be manufactured by using the apparatus and method described in U.S. Patent No. 8,486,363 in

[0022] to

[0048] in which (i) they are introduced one or more hydrocarbon precursor materials capable of forming two-carbon fragment species (such as n-propanol, ethane, ethylene, acetylene, vinyl chloride, 1,2-dichloroethane, allyl alcohol, propianoaldehyde, and / or vinyl bromide ) in a thermal zone (such as a plasma), and (ii) the hydrocarbon is heated in the thermal zone at a temperature of at least 1,000 ° C to form the graphene carbon particles. In other embodiments, the thermally produced graphite carbon particles can be manufactured by using the apparatus and method described in U.S. Patent No. 8,486,364 in

[0015] to

[0042] in which (i) a precursor material is introduced of methane (such as a material comprising at least 50 percent methane, or in some cases, gaseous or liquid methane of at least 90 or 99 percent pure or more) in a thermal zone (such as a plasma), and (ii) the methane precursor is heated in the thermal zone to form the graphene carbon particles. These methods can produce graphene carbon particles that have at least some, in some cases all, of the characteristics described above. [00030] During the production of the graphene carbon particles by the thermal production methods described above, a precursor containing carbon is provided as a feedstock that can be contacted with an inert carrier gas. The precursor material containing carbon can be heated in a thermal zone, for example, by a plasma system. In certain embodiments, the precursor material is heated to a temperature of at least 3,500 ° C, for example, from a temperature of more than 3,500 ° C or 4,000 ° C to 10,000 ° C or 20,000 ° C. Although the thermal zone can be generated by a plasma system, it is to be understood that any other suitable heating system can be used to create the thermal zone, such as different types of furnaces including electrically heated tube furnaces and the like. [00031] The gaseous stream can be contacted with one or more cooling streams that are injected into the plasma chamber through at least one injection port of cooling current. The cooling current can cool the gas stream to facilitate the formation or control of the particle size or morphology of the graphene carbon particles. In certain embodiments of the invention, after contacting the gaseous product stream with the cooling streams, the ultra-fine particles can pass through a converging member. After the graphene carbon particles leave the plasma system, they can be collected. Any suitable means can be used to separate the graphene carbon particles from the gas flow, such as, for example, a bag filter, cylindrical separator or deposition on a substrate. [00032] Without being bound by any theory, it is currently believed that prior methods of manufacturing thermally produced graphite carbon particles are particularly suitable for producing graphite carbon particles having a relatively low thickness and relatively high aspect ratio in relation to relatively low oxygen content, as described above. Furthermore, it is believed that these methods produce a substantial amount of graphene carbon particles having a substantially curved, wavy, wrinkled or warped morphology (referred to herein as a "3D" morphology), as compared to the production of particles having a substantially two-dimensional (or flat) morphology. It is believed that this feature will be reflected in the compressed density characteristics previously described and is believed to be beneficial in the present invention because, it is currently believed, when a significant portion of the graphene carbon particles have a 3D morphology, the "edge to edge" and "edge to face" contact between graphene carbon particles within the composition can be promoted. It is believed that this is because particles that have a 3D morphology are less likely to be added in the composition (due to lower Van der Waals forces) than particles that have a two-dimensional morphology. Furthermore, it is currently believed that even in the case of face-to-face contact between the particles having a 3D morphology, since the particles can have more than one facial plane, the entire particle surface does not couple with a single interaction of "face to face" with another single particle, but instead can participate in interactions with other particles, which include other "face to face" interactions, in other planes. As a result, it is currently believed that graphene carbon particles having a 3D morphology provide the best conductive path in the present compositions and it is currently believed that they will be useful to obtain electrical conductivity characteristics sought by the embodiments of the invention. present invention, particularly when graphene carbon particles are present in the composition in relatively low amounts. [00033] In certain embodiments, thermally produced graphite carbon particles can be combined with other types of graphene particles, such as those obtained from commercial sources, for example, from Angstron, XC Sciences and other commercial sources. In these embodiments, commercially available graphite carbon particles may comprise exfoliated graphite and may have different characteristics compared to thermally produced graphite carbon particles such as different size distributions, thicknesses, aspect ratios, structural morphologies, oxygen content, and chemical functionality in the basal planes / edges. [00034] When thermally produced graphite carbon particles are combined with commercially available graphene carbon particles according to embodiments of the invention, a bimodal distribution, trimodal distribution, etc. can be achieved. Characteristics of graphene carbon particles. For example, the graphene carbon particles contained in the coatings may have multimodal particle size distributions, distributions of aspect ratios, morphologies structural, edge functionality differences, oxygen content, and the like. Table 1 below lists the average particle sizes, thickness and aspect ratios for thermally produced graphite carbon particles compared to certain commercially available graphite carbon particles produced from exfoliated graphite. [00035] In an embodiment of the present invention in which both thermally produced graphite carbon particles and commercially available graphite carbon particles, for example, exfoliated graph, are added to a coating composition to produce a particle size distribution. bimodal graphene, the relative amounts of the different types of graphene carbon particles are controlled to produce desired conductivity properties of the coatings. For example, thermally produced graphite carbon particles may comprise from 1 to 50 weight percent, and commercially available graphite carbon particles may comprise from 50 to 99 weight percent, based on the total weight of the particles of carbon dioxide. graphene carbon. In certain embodiments, the thermally produced graphite carbon particles may comprise 2 to 20 weight percent, or 5 to 10 or 12 weight percent. [00036] In addition to resin and particle components of graphene carbon, the coatings of the present invention may include additional components conventionally added to coating compositions, such as crosslinkers, pigments, inks, flow aids, defoamers, dispersants, solvents, UV absorbers, catalysts and surfactants. [00037] In certain embodiments, the coating compositions are substantially free of certain components such as polyalkyleneimines, graphite, or other components. For example, the term "substantially free of polyalkyleneimines" means that the polyalkyleneimines are not added intentionally, or are present as impurities in trace amounts, for example, less than 1 weight percent or less than 0.1 weight percent. It has been found that the coatings of the present invention have good adhesion properties without the need to add polyalkyleneimines. The term "substantially free of graphite" means that the graphite is not added intentionally, or is present as an impurity in the trace amounts, for example, less than 1 weight percent, or less than 0.1 weight percent. In certain embodiments, the graphite may be present in the coatings in smaller amounts, for example, less than 5 weight percent or less than 1 weight percent coating. If graphite is present, it is conventionally in a less than graphene, less than 30 weight percent based on the combined weight of graphite and graphene, for example, less than 20 or 10 weight percent. [00038] The coating compositions of the present invention can be manufactured by different normal methods in which the graphene carbon particles are mixed with the film-forming resins and other components of the coating compositions. For example, for two-part coating systems, the graphene carbon particles can be dispersed in part A and / or part B. In certain embodiments, the graphene carbon particles are dispersed in part A by different mixing techniques. such as sonication, high speed mixing, milling with media and the like. In certain embodiments, the graphene carbon particles can be mixed into the coating compositions using high energy and / or high shear techniques such as sonication, 3-roll milling, ball milling, wear milling, rotor / stator mixers. , and similar. [00039] According to certain embodiments, the coatings of the present invention possess desirable mechanical properties, increased IR absorption, increased "degree of depth", increased thermal conductivity, decreased permeability to small Molecules such as water and oxygen can also be advantageous for these same coatings. [00040] It is proposed that the following examples illustrate different aspects of the invention, and it is not proposed that they limit the scope of the invention.

Example 1 [00041] The electrical conductivities of coatings containing thermally produced graphite carbon particles were compared with similar coatings containing commercial graphene particles, and not containing these particles. The coating compositions were made with aqueous latex particles that are stable in N-methyl-pyrrolidone (NMP) solvent. The acrylic latex particles were crosslinked and functionalized with epoxy, but do not need to be functionalized to function. The latex forms a film at elevated temperatures and functions as the binder to hold the film. The thermally produced graphite carbon particles, labeled PPG A and PPG B, were produced by the thermal plasma production method using methane as a precursor material described in U.S. Patent No. 8,486,364. The graphically produced PPG A and PPG B graphgenic carbon particles have a surface area of approximately 250-280 m2 / g and have a size of approximately 100-200 n. The particles of commercially available graphene carbon included: XG-M5 (from XG Sciences having an average particle size of 5 microns, thickness of approximately 6 nm, and BET surface area of from 120 to 150 square meters per gram); XG-C750 (from XG Sciences having an average particle size of approximately 1.5 microns, thickness of approximately 2 nm, and BET surface area of 750 square meters per gram); and PDR (from Angstron Materials having an average particle size of approximately 10 microns, thickness of approximately 1 nm and BET surface area of 400 to 800 square meters per gram). Prior to the addition of the graphene carbon particles to the coating solution, samples were diluted to 0.25-2.5 weight percent in NMP solvent and sonicated horn for 15 minutes. The PPG B sample was dispersed with twice the sonication energy per graphene unit compared to the PPG A sample. The final coating composition was then manufactured by mixing latex, NMP solvent, and the pre-dispersed graphene carbon particles. . An ultrasound bath was then applied to the samples for 15 minutes. After sonication, the samples were passed through a 150 mesh filter and then pulled down onto glass substrates in a 6 milliliter wet thick film. The wet films flashed at room temperature for 15 minutes, followed by a Curing in oven at 100 ° C for 30 minutes. [00042] Figure 1 graphically illustrates the conductivities of the coatings containing the graphically produced PPG A and PPG B graphite carbon particles at different charges, as compared to other commercial graphite carbon particles and a control coating that does not contain these particles , that conductivity was not measured. Although the PPG A and PPG B particles are approximately one order of magnitude smaller than the M5 particles, they produce similar electrical conductivities. As the particles become smaller, the resistance should increase in the film in a similar load, that is, comparing the M5 with PDR, which is an average particle size of "10 vs. 5 microns and the C750 that is 1.5 microns However, thermally produced graphene particles provide a liner of lower strength This may be due to the extremely low oxygen content of the thermally produced graphite carbon particles and the fact that its edge functionality can be limited to CH bonds. vs C-0 bonds, CN, observed in commercial graphene samples, which produce a lower particle to particle contact resistance for thermally produced graphene.The thermally produced graphene may also be inherently more conductive due to its structure crystalline turbo-estrática.

Example 2 [00043] Coatings were produced comprising a type of commercially available graphene carbon particles separately, and in combination with other graphene carbon particles (including thermally produced graphite carbon particles), and were measured for electrical conductivity. Coating compositions were made with 10 weight percent graphene carbon particles: either axGnP C-300 (from XG Sciencies having an average particle size of 1.5 microns, thickness of approximately 2 nm, and BET surface area of 300 square meters per gram), xGnP C-750 (from XG Sciences as described in Example 1), xGnP M-25 (from XG Sciences having an average particle size of 25 microns, thickness of 6.8 nm, and surface area BET of 120-150 square meters per gram), or thermally produced graphitic carbon particles PPG, with 1.67 weight percent ethylcellulose (Aqualon, Ashland), and with 88.33 weight percent deionized water. These coating compositions were dispersed by adding 70g of each in 8-ounce glass flasks with 220g of SEPR, 1.0-1.25m milling media of Ermil. The samples in the flasks were shaken for 4 hours using a Lau disperser (Model DAS 200, Lau, GmbH). The grinding media was then filtered from the coating compositions. The mixtures of these coating compositions were then prepared, such that from the total of 10 weight percent of the graphene carbon in each of the mixtures, there were two types of graphene carbon particles in the following percentages by weight: 92% of xGnP M-25 and 8% of thermally produced graphite carbon particles PPG, 92% xGnP M-25 and 8% xGnP C-300, and 92% xGnP M-25 and 8% xGnP C-750. Each of these mixtures as well as the coating composition with only xGnP M-25 were applied as 1-2 mm wide lines in a serpentine circuit pattern to a 2 x 3 inch glass slide (Fisherbrand, Pre-washed Plain) , using a dispensing jet (PICO valve, VOLATILE MATERIAL-100, Nordson, EFD), and a desktop robot (2504N, Janome) and then dried in an oven at 212 ° F (100 ° C) for 30 minutes. The electrical conductivity of each coated sample was determined by first measuring the strength of the serpentine circuit vs. the length of the circuit line. Then, the cross-sectional area of the serpentine lines was measured using a needle profilometer (Dektak). Using the measured values for the cross-sectional area (A) and the resistance (R) for a given length (L) of the circuit, the resistivity (p) was calculated using the equation p = Ra / L. Then the conductivity (o) was calculated by taking the reciprocal of the resistivity, s = 1 / r. [00044] The results are shown in Figure 2. The addition of a small amount of thermally produced graphically produced graphite carbon particles significantly increases the conductivity, by approximately 200%, over a coating composition containing only a graphite carbon of large platelet type (xGnP M-25). Figure 2 shows that small additions of other commercially available graphite carbon particles did not increase the conductivity significantly (only an increase of approximately 50% for xGnP C-300 and only an increase of approximately 90% for xGnP C-750 ). [00045] For purposes of this description, it is to be understood that the invention may assume different alternate variations and pass sequences, except where expressly specified otherwise. In addition, in place of any of the operational examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims will be understood as being modified in all cases by the term "approximately". Accordingly, unless otherwise indicated, the numerical parameters set forth in the following specification and the appended claims are approximations that may vary depending on the desired properties that are to be obtained by the present invention. At least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be considered at least taking into account the number of significant digits reported and when applying ordinary rounding techniques. [00046] Although the numerical ranges and parameters that set forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors that necessarily result from the normal variation found in their respective test measurements. [00047] Also, it is to be understood that any numerical range expressed herein is intended to include all sub-ranges subsumed herein. For example, a range of "1 to 10" is proposed to include all sub-intervals between (and including) the minimum value expressed of 1 and the maximum value expressed of 10, that is, having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10. [00048] In this application, the use of the singular includes the plural and the plural encompasses the singular, unless specifically indicated otherwise. In addition, in this application, the use of, "or" means "and / or" unless specifically stated otherwise, although "and / or" may be used explicitly in certain cases. [00049] It will be readily appreciated by those skilled in the art that modifications to the invention may be made without departing from the concepts described in the foregoing description. These modifications are to be considered as being included within the following claims unless the claims, by their language, expressly indicate otherwise. Accordingly, the particular embodiments described in detail herein are illustrative only and do not limit the scope of the invention which will give the full scope of the appended claims and any and all equivalents thereof.

Claims (24)

1. An electrically conductive coating composition comprising: a film-forming resin; Y thermally produced graphite carbon particles, wherein when the coating composition is cured it has a higher electrical conductivity than an electrical conductivity of the same coating composition without the thermally produced graphite carbon particles.

2. The electrically conductive coating composition of claim 1, wherein the thermally produced graphite carbon particles comprise from 1 to 95 weight percent of the coating composition based on the total solids content of the coating composition.

3. The electrically conductive coating composition of claim 1, wherein the thermally produced graphite carbon particles comprise more than 40 weight percent of the coating composition based on the total solids content of the coating composition.

4. The electrically conductive coating composition of claim 1, wherein the thermally produced graphite carbon particles comprise less than 20 weight percent of the coating composition based on the total solids content of the coating composition.

5. The electrically conductive coating composition of claim 1, wherein the thermally produced graphite carbon particles have an oxygen content of less than 1.5 atomic percent.

6. The electrically conductive coating composition of claim 1, wherein the thermally produced graphite carbon particles have a BET surface area of less than 300 square meters per gram.

7. The electrically conductive coating composition of claim 1, wherein the thermally produced graphite carbon particles are produced by: introducing a precursor material comprising a methane or a hydrocarbon material capable of forming two-carbon fragment species in a thermal zone having a temperature of more than 3,500 ° C at 20,000 ° C; heating the precursor material in the thermal zone to form the graphene carbon particles of the precursor material; Y Collect graphene carbon particles that have an average aspect ratio greater than 3: 1.

8. The electrically conductive coating composition of claim 1, further comprising graphite carbon particles of exfoliated graphite.

9. The electrically conductive coating composition of claim 8, wherein the thermally produced graphite carbon particles comprise from 1 to 20 weight percent, and the graphite carbon particles of exfoliated graphite comprise from 80 to 99 weight percent, with based on the total weight of the graphene carbon particles.

10. The electrically conductive coating composition of claim 1, wherein the film-forming resin comprises epoxy resins, acrylic polymers, polyester polymers, polyurethane polymers, polyamide polymers, polyether polymers, bisphenol A based epoxy polymers, polymers of polysiloxane, styrenes, ethylenes, butylenes, capsid polymers, non-aqueous dispersed polymer particles, copolymers thereof, and mixtures thereof.

11. The electrically conductive coating composition of claim 1, wherein the film formation comprises a latex resin or a non-aqueous dispersed resin.

12. The electrically conductive coating of claim 1, wherein the coating is substantially free of graphite.

13. The electrically conductive coating of Claim 1, wherein the coating is substantially free of polyalkyleneimines.

14. The electrically conductive coating composition of claim 1, wherein the electrical conductivity of the cured coating composition is at least 1.00 S / m.

15. The electrically conductive coating composition of claim 13, wherein the electrical conductivity of the cured coating composition is at least 10,000 S / m.

16. An electrically conductive coating comprising: a polymeric resin film; Y thermally produced graphite carbon particles dispersed in the polymeric resin film.

17. The electrically conductive coating of claim 16, wherein the electrically conductive coating has an electrical conductivity of at least 10 S / m.

18. The electrically conductive coating of claim 16, wherein the electrically conductive coating has an electrical conductivity of at least 1,000 S / m.

19. The electrically conductive coating of claim 16, wherein the coating electrically conductive has an electrical conductivity of at least 10,000 S / m.

20. The electrically conductive coating of claim 16, further comprising graphite carbon particles of exfoliated graphite dispersed in the polymeric film.

21. The electrically conductive coating of claim 16, wherein the polymeric resin comprises epoxy resins, acrylic polymers, polyester polymers, polyurethane polymers, polyamide polymers, polyether polymers, bisphenol A based epoxy polymers, polysiloxane polymers, styrenes , ethylenes, butylenes, capsid polymers, non-aqueous dispersed polymer particles, copolymers thereof, and mixtures thereof.

22. The electrically conductive coating of claim 16, wherein the coating has a dry film thickness of 1 to 100 microns.

23. A method of manufacturing an electrically conductive coating composition comprising admixing thermally produced graphite carbon particles with a film-forming resin.

24. The method of claim 23, wherein the thermally produced graphite carbon particles are produced by: introduce a precursor material comprising a methane or a hydrocarbon material capable of forming two-carbon fragment species in a thermal zone having a temperature of more than 3,500 ° C at 20.00 ° C; heating the precursor material in the thermal zone to form the graphene carbon particles of the precursor material; Y Collect graphene carbon particles that have an average aspect ratio greater than 3: 1.