WO2019098726A1

WO2019098726A1 - Coating composition for heating cookware comprising spherical graphene powder and heating cookware

Info

Publication number: WO2019098726A1
Application number: PCT/KR2018/014048
Authority: WO
Inventors: Jiyoung Yoon; Hanna BAE; Jeonghan Park
Original assignee: Hayoon Co., Ltd.
Priority date: 2017-11-17
Filing date: 2018-11-16
Publication date: 2019-05-23
Also published as: KR20190056767A

Abstract

Provided herein are compositions comprising spherical graphene and methods for preparing said compositions. The compositions can be used for coating cookware. Also disclosed herein are methods of coating a cookware using the compositions.

Description

COATING COMPOSITION FOR HEATING COOKWARE COMPRISING SPHERICAL GRAPHENE POWDER AND HEATING COOKWARE

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Korean Application No. 10-2017-0154057, filed on November 17, 2017, which is hereby incorporated by reference in its entirety for all purposes.

The present invention relates to a composition comprising spherical graphene. The composition can be used for coating cookware with superior heat conductivity and durability. The present invention relates to a method of preparing the composition and cookware.

Heating cookware with conventional coatings are generally manufactured by coating a body of metal such as aluminum with a fluoroplastic (TEFLON) or ceramic coating. In some cases, a glaze can be applied to a metal surface for making the coating. In some cases, a melting ingredient can be melted by using a thermal spray apparatus with an oxygen acetylene flame and spray the same onto a metal surface using compressed air.

However, there are drawbacks with the conventional coatings. For example, the burning of fluoroplastics, such as polytetrafluoroethylene (PTFE), at temperatures of 200℃ or greater produces plastic environmental hormones and carcinogens such as perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonate (PFOS), which can be harmful for the human body. Accordingly, the use of fluoroplastics has been the subject of much debate, and of environmental regulations and institutional sanctions. Similarly, ceramic coatings have the disadvantage of weakening the thermal conductivity of metal. Ceramic coatings can also be peeled off over time with use, and can lead to the stickiness and corrosion of the cookware.

Accordingly, there is a need to develop a new coating composition having superior thermal conductivity and durability without the above drawbacks.

In one aspect, disclosed herein is a composition comprising: a spherical graphene powder comprising a Brunauer, Emmett and Teller (BET) specific surface area of at least about 400 m²/g. In some cases, the BET specific surface area of the spherical graphene powder can be about 400 m²/g to about 800 m²/g. In some cases, the BET specific surface area of the spherical graphene powder can be at least about 400 m²/g. In some cases, the BET specific surface area of the spherical graphene powder can be at most about 800 m²/g. In some cases, the BET specific surface area of the spherical graphene powder can be about 400 m²/g to about 500 m²/g, about 400 m²/g to about 600 m²/g, about 400 m²/g to about 700 m²/g, about 400 m²/g to about 800 m²/g, about 500 m²/g to about 600 m²/g, about 500 m²/g to about 700 m²/g, about 500 m²/g to about 800 m²/g, about 600 m²/g to about 700 m²/g, about 600 m²/g to about 800 m²/g, or about 700 m²/g to about 800 m²/g. In some cases, the BET specific surface area of the spherical graphene powder can be about 400 m²/g, about 500 m²/g, about 600 m²/g, about 700 m²/g, or about 800 m²/g.

In some cases, the BET specific surface area is at least 20% larger than a corresponding carbon nanotube powder. In some cases, the BET specific surface area is at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% larger than a corresponding carbon nanotube powder. In some cases, the BET specific surface area is about 20% to about 40%, about 20% to about 60%, about 20% to about 80%, about 20% to about 100%, about 40% to about 60%, about 40% to about 80%, about 40% to about 100%, about 60% to about 80%, about 60% to about 100%, or about 80% to about 100% larger than a corresponding carbon nanotube powder. In some cases, the corresponding carbon nanotube powder have the same weight as the spherical graphene powder.

In some cases, the spherical graphene powder comprises at least 10% (w/w) of the composition. In some cases, the spherical graphene powder comprises at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% (w/w) of the composition. In some cases, the spherical graphene powder comprises about 20% to about 40%, about 20% to about 60%, about 20% to about 80%, about 20% to about 95%, about 40% to about 60%, about 40% to about 80%, about 40% to about 95%, about 60% to about 80%, about 60% to about 95%, or about 80% to about 95% (w/w) of the composition.

In some cases, the composition further comprises an inorganic binder. In some cases, the inorganic binder comprises a silane compound, a silica sol, or both. In some cases, the silane compound comprises methyltrimethoxysilane, ethyltrimethoxysilane, normal propyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, normal propyltriethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, triple fluoropropyl trimethoxysilane, tridecafluorooctyl trimethoxysilane, tetraethoxysilane, heptadecafluorodecyl trimethoxysilane, or any combination thereof.

In some cases, the silica sol comprises a silica powder with an average particle size of 0.2 to 1.0 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.2 to 0.4 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.2 to 0.6 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.2 to 0.8 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.4 to 0.6 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.4 to 0.8 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.4 to 1.0 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.6 to 0.8 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.6 to 1.0 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.8 to 1.0 μm. In some cases, the silica powder is dispersed in water.

In some cases, the composition further comprises a solvent. In some cases, the solvent comprises water, an alcohol-based solvent, a Cellsolve solvent, an ester-based solvent, an aqueous solvent, a ketone-based solvent, an amine-based solvent, an amide-based solvent, a halogenated hydrocarbon solvent, an ether-based solvent, a furan-based solvent, or any combination thereof. In some cases, the solvent is water, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), or any combination thereof.

In some cases, the composition further comprising a metal salt. In some cases, the metal salt comprises a silver salt, an iron salt, a copper salt, an aluminum salt, a nickel salt, or any combination thereof. In some cases, the metal salt comprises an acetate salt, a carbonate salt, a chloride salt, a citrate salt, a cyanide salt, a fluoride salt, a nitrate salt, a nitrite salt, a phosphate salt, a sulfate salt, or any combination thereof. In some cases, the metal salt comprises silver acetate, silver carbonate, silver chloride, silver citrate, silver cyanide, silver fluoride, silver nitrate, silver nitrite, silver phosphate, silver sulfate, or any combination thereof. In some cases, the metal salt comprises iron acetate, iron carbonate, iron chloride, iron citrate, iron cyanide, iron fluoride, iron nitrate, iron nitrite, iron phosphate, iron sulfate, or any combination thereof. In some cases, the metal salt comprises copper acetate, copper carbonate, copper chloride, copper citrate, copper cyanide, copper fluoride, copper nitrate, copper nitrite, copper phosphate, copper sulfate, or any combination thereof. In some cases, the metal salt comprises aluminum acetate, aluminum carbonate, aluminum chloride, aluminum citrate, aluminum cyanide, aluminum fluoride, aluminum nitrate, aluminum nitrite, aluminum phosphate, aluminum sulfate, or any combination thereof. In some cases, the metal salt comprises nickel acetate, nickel carbonate, nickel chloride, nickel citrate, nickel cyanide, nickel fluoride, nickel nitrate, nickel nitrite, nickel phosphate, nickel sulfate, or any combination thereof. In some cases, the metal salt comprises aluminum nitrate, copper nitrate, or any combination thereof.

In some cases, the composition further comprises graphene oxide. In some cases, the metal salt and graphene oxide has a weight ratio (metal salt : graphene oxide) of at least about 1:1. For example, the metal salt and graphene oxide has a weight ratio of at least about 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1. In some cases, the weight ratio is about 1:1 to about 2:1, about 1:1 to about 4:1, about 1:1 to about 6:1, about 1:1 to about 8:1, about 1:1 to about 10:1, about 1:1 to about 15:1, about 1:1 to about 20:1, about 2:1 to about 4:1, about 2:1 to about 6:1, about 2:1 to about 8:1, about 2:1 to about 10:1, about 2:1 to about 15:1, about 2:1 to about 20:1, about 4:1 to about 6:1, about 4:1 to about 8:1, about 4:1 to about 10:1, about 4:1 to about 15:1, about 4:1 to about 20:1, about 6:1 to about 8:1, about 6:1 to about 10:1, about 6:1 to about 15:1, about 6:1 to about 20:1, about 8:1 to about 10:1, about 8:1 to about 15:1, about 8:1 to about 20:1, about 10:1 to about 15:1, about 10:1 to about 20:1, or about 15:1 to about 20:1. In some cases, the weight ratio is about 1:1, about 2:1, about 4:1, about 6:1, about 8:1, about 10:1, about 15:1, or about 20:1.

In some cases, the composition further comprises a linear or sheet carbon material. In some cases, the linear or sheet carbon material comprises sheet graphene, graphite, carbon nanotubes, or any combination thereof. In some cases, the spherical graphene powder and the linear or sheet carbon material has a weight ratio (spherical graphene powder : linear or sheet carbon material) of about 1:9 to about 9:1. In some cases, the weight ratio is about 1:9 to about 1:3, about 1:6 to about 1:1, 1:3 to about 3:1, about 1:1 to about 1:6, about 3:1 to about 9:1, about 6:1 to about 9:1. In some cases, the spherical graphene powder and the linear or sheet carbon material has a weight ratio of about 4:6 to about 6:4.

In some cases, the composition further comprises an additive. In some cases, the additive comprises an antimicrobial agent, an anticorrosive agent, a filler, a pigment, or any combination thereof. In some cases, the composition is a coating composition.

In another aspect, disclosed herein is a cookware, comprising a heating cookware main body, and a cured product of any composition disclosed herein formed on the heating cookware main body. In some cases, the cookware comprises a frying pan, a saucepan, a pot, a kettle, or a grill. In some cases, the heating cookware main body comprises iron, steel, stainless steel, copper, aluminum, ceramic, or any combination thereof.

In another aspect, disclosed herein is a method for preparing a compositing, comprising: (i) dispersing graphene oxide in a solvent to form a graphene oxide dispersion; (ii) drying the graphene oxide dispersion to obtain a spherical graphene oxide powder; and (iii) reducing the spherical graphene oxide powder to form the compositing.

In some cases, the method further comprises oxidizing graphite to form the graphene oxide. In some cases, the method further comprises oxidizing graphite using the Hummers method or the modified Hummers method. In some cases, the solvent comprises water, an alcohol-based solvent, a Cellsolve solvent, an ester-based solvent, an aqueous solvent, a ketone-based solvent, an amine-based solvent, an amide-based solvent, a halogenated hydrocarbon solvent, an ether-based solvent, a furan-based solvent, or any combination thereof. In some cases, the solvent is water, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), or any combination thereof.

In some cases, the method further comprises mixing a metal salt with the graphene oxide dispersion. In some cases, the metal salt comprises a silver salt, an iron salt, a copper salt, an aluminum salt, a nickel salt, or any combination thereof. In some cases, the metal salt comprises an acetate salt, a carbonate salt, a chloride salt, a citrate salt, a cyanide salt, a fluoride salt, a nitrate salt, a nitrite salt, a phosphate salt, a sulfate salt, or any combination thereof. In some cases, the metal salt comprises silver acetate, silver carbonate, silver chloride, silver citrate, silver cyanide, silver fluoride, silver nitrate, silver nitrite, silver phosphate, silver sulfate, or any combination thereof. In some cases, the metal salt comprises iron acetate, iron carbonate, iron chloride, iron citrate, iron cyanide, iron fluoride, iron nitrate, iron nitrite, iron phosphate, iron sulfate, or any combination thereof. In some cases, the metal salt comprises copper acetate, copper carbonate, copper chloride, copper citrate, copper cyanide, copper fluoride, copper nitrate, copper nitrite, copper phosphate, copper sulfate, or any combination thereof. In some cases, the metal salt comprises aluminum acetate, aluminum carbonate, aluminum chloride, aluminum citrate, aluminum cyanide, aluminum fluoride, aluminum nitrate, aluminum nitrite, aluminum phosphate, aluminum sulfate, or any combination thereof. In some cases, the metal salt comprises nickel acetate, nickel carbonate, nickel chloride, nickel citrate, nickel cyanide, nickel fluoride, nickel nitrate, nickel nitrite, nickel phosphate, nickel sulfate, or any combination thereof. In some cases, the metal salt comprises aluminum nitrate, copper nitrate, or any combination thereof.

In some cases, the metal salt and graphene oxide has a weight ratio (metal salt : graphene oxide) of at least about 1:1. For example, the metal salt and graphene oxide has a weight ratio of at least about 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1. In some cases, the weight ratio is about 1:1 to about 2:1, about 1:1 to about 4:1, about 1:1 to about 6:1, about 1:1 to about 8:1, about 1:1 to about 10:1, about 1:1 to about 15:1, about 1:1 to about 20:1, about 2:1 to about 4:1, about 2:1 to about 6:1, about 2:1 to about 8:1, about 2:1 to about 10:1, about 2:1 to about 15:1, about 2:1 to about 20:1, about 4:1 to about 6:1, about 4:1 to about 8:1, about 4:1 to about 10:1, about 4:1 to about 15:1, about 4:1 to about 20:1, about 6:1 to about 8:1, about 6:1 to about 10:1, about 6:1 to about 15:1, about 6:1 to about 20:1, about 8:1 to about 10:1, about 8:1 to about 15:1, about 8:1 to about 20:1, about 10:1 to about 15:1, about 10:1 to about 20:1, or about 15:1 to about 20:1. In some cases, the weight ratio is about 1:1, about 2:1, about 4:1, about 6:1, about 8:1, about 10:1, about 15:1, or about 20:1. For example, the weight ratio is about 1:1 to about 20:1.

In some cases, the method further comprises adding an inorganic binder to the graphene oxide dispersion. In some cases, the inorganic binder comprises a silane compound, a silica sol, or both. In some cases, the silane compound comprises methyltrimethoxysilane, ethyltrimethoxysilane, normal propyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, normal propyltriethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, triple fluoropropyl trimethoxysilane, tridecafluorooctyl trimethoxysilane, tetraethoxysilane, heptadecafluorodecyl trimethoxysilane, or any combination thereof.

In some cases, the silica sol comprises a silica powder with an average particle size of 0.2 to 1.0 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.2 to 0.4 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.2 to 0.6 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.2 to 0.8 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.4 to 0.6 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.4 to 0.8 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.4 to 1.0 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.6 to 0.8 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.6 to 1.0 μm. In some cases, the silica sol comprises a silica powder with an average particle size of 0.8 to 1.0 μm. In some cases, the silica powder is dispersed in water. In some cases, the silica powder is dispersed in water.

In some cases, the drying comprises spray drying. In some cases, the drying is performed with an inlet temperature at 100 to 150 ℃, an outlet temperature at 50 to 70 ℃, a feed rate at 25 to 30 Hz, or any combination thereof. In some cases, the drying is performed with an inlet temperature of about 100 ℃ to about 150 ℃. In some cases, the drying is performed with an inlet temperature of at least about 100 ℃. In some cases, the drying is performed with an inlet temperature of at most about 150 ℃. In some cases, the drying is performed with an inlet temperature of about 100 ℃ to about 110 ℃, about 100 ℃ to about 120 ℃, about 100 ℃ to about 130 ℃, about 100 ℃ to about 140 ℃, about 100 ℃ to about 150 ℃, about 110 ℃ to about 120 ℃, about 110 ℃ to about 130 ℃, about 110 ℃ to about 140 ℃, about 110 ℃ to about 150 ℃, about 120 ℃ to about 130 ℃, about 120 ℃ to about 140 ℃, about 120 ℃ to about 150 ℃, about 130 ℃ to about 140 ℃, about 130 ℃ to about 150 ℃, or about 140 ℃ to about 150 ℃. In some cases, the drying is performed with an inlet temperature of about 100 ℃, about 110 ℃, about 120 ℃, about 130 ℃, about 140 ℃, or about 150 ℃. In some cases, the drying is performed with an outlet temperature of about 50 ℃ to about 70 ℃. In some cases, the drying is performed with an outlet temperature of at least about 50 ℃. In some cases, the drying is performed with an outlet temperature of at most about 70 ℃. In some cases, the drying is performed with an outlet temperature of about 50 ℃ to about 60 ℃, about 50 ℃ to about 70 ℃, or about 60 ℃ to about 70 ℃. In some cases, the drying is performed with an outlet temperature of about 50 ℃, about 60 ℃, or about 70 ℃. In some cases, the drying is performed with a feed rate of about 25 Hz to about 30 Hz. In some cases, the drying is performed with a feed rate of at least about 25 Hz. In some cases, the drying is performed with a feed rate of at most about 30 Hz. In some cases, the drying is performed with a feed rate of about 25 Hz to about 26 Hz, about 25 Hz to about 27 Hz, about 25 Hz to about 28 Hz, about 25 Hz to about 29 Hz, about 25 Hz to about 30 Hz, about 26 Hz to about 27 Hz, about 26 Hz to about 28 Hz, about 26 Hz to about 29 Hz, about 26 Hz to about 30 Hz, about 27 Hz to about 28 Hz, about 27 Hz to about 29 Hz, about 27 Hz to about 30 Hz, about 28 Hz to about 29 Hz, about 28 Hz to about 30 Hz, or about 29 Hz to about 30 Hz. In some cases, the drying is performed with a feed rate of about 25 Hz, about 26 Hz, about 27 Hz, about 28 Hz, about 29 Hz, or about 30 Hz.

In some cases, the reducing the spherical graphene oxide powder comprises irradiating the spherical graphene oxide powder with microwave radiation. In some cases, the irradiating the spherical graphene oxide powder is performed in a reducing atmosphere. In some cases, the irradiating the spherical graphene oxide powder is carried out between 30 seconds and 3 minutes. In some cases, the irradiating the spherical graphene oxide powder is carried out in about 0.5 mins to about 3 mins. In some cases, the irradiating the spherical graphene oxide powder is carried out in at least about 0.5 mins. In some cases, the irradiating the spherical graphene oxide powder is carried out in at most about 3 mins. In some cases, the irradiating the spherical graphene oxide powder is carried out in about 0.5 mins to about 1 min, about 0.5 mins to about 2 mins, about 0.5 mins to about 3 mins, about 1 min to about 2 mins, about 1 min to about 3 mins, or about 2 mins to about 3 mins. In some cases, the irradiating the spherical graphene oxide powder is carried out in about 0.5 mins, about 1 min, about 2 mins, or about 3 mins. In some cases, the irradiating the spherical graphene oxide powder is carried out at an output of about 300W to 1000W, for example, 700W.

In some cases, the method further comprises heating said spherical graphene oxide powder. In some cases, the heating the spherical graphene oxide powder is carried out at a temperature of about 300 ℃ to about 400 ℃. In some cases, the heating the spherical graphene oxide powder is carried out at a temperature of at least about 300 ℃. In some cases, the heating the spherical graphene oxide powder is carried out at a temperature of at most about 400 ℃. In some cases, the heating the spherical graphene oxide powder is carried out at a temperature of about 300 ℃ to about 350 ℃, about 300 ℃ to about 400 ℃, or about 350 ℃ to about 400 ℃. In some cases, the heating the spherical graphene oxide powder is carried out at a temperature of about 300 ℃, about 350 ℃, or about 400 ℃. In some cases, the heating the spherical graphene oxide powder is carried out in a reducing atmosphere.

In another aspect, disclosed herein is a method for coating a cookware, comprising: (a) applying any composition disclosed herein or a composition prepared by any method disclosed herein on a cookware main body; and (b) heat curing the composition on the cookware main body.

In some cases, the method further comprises applying a thermal conductive layer on the cookware main body. In some cases, the method further comprises dispersing the composition prior to applying the composition. In some cases, the dispersing the composition is performed using a microfluidizer. In some cases, the dispersing the composition is performed for about 10 mins to about 30 mins. In some cases, the dispersing the composition is performed for at least about 10 mins. In some cases, the dispersing the composition is performed for at most about 30 mins. In some cases, the dispersing the composition is performed for about 10 mins to about 20 mins, about 10 mins to about 30 mins, or about 20 mins to about 30 mins. In some cases, the dispersing the composition is performed for about 10 mins, about 20 mins, or about 30 mins. In some cases, the applying the composition is spray coating.

In some cases, the method further comprising pre-heating the composition prior to applying the composition. In some cases, the method comprises pre-heating the composition to about 50 ℃ to about 70 ℃. In some cases, the method comprises pre-heating the composition to at least about 50 ℃. In some cases, the method comprises pre-heating the composition to at most about 70 ℃. In some cases, the method comprises pre-heating the composition to about 50 ℃ to about 60 ℃, about 50 ℃ to about 70 ℃, or about 60 ℃ to about 70 ℃. In some cases, the method comprises pre-heating the composition to about 50 ℃, about 60 ℃, or about 70 ℃.In some cases, the method comprises pre-heating the composition to about 50 to 60 ℃.

In some cases, the heat curing is carried out using hot air heating, infra-red heating, or induction heating. In some cases, the heat curing is carried out for about 5 mins to about 10 mins. In some cases, the heat curing is carried out for at least about 5 mins. In some cases, the heat curing is carried out for at most about 10 mins. In some cases, the heat curing is carried out for about 5 mins to about 6 mins, about 5 mins to about 7 mins, about 5 mins to about 8 mins, about 5 mins to about 9 mins, about 5 mins to about 10 mins, about 6 mins to about 7 mins, about 6 mins to about 8 mins, about 6 mins to about 9 mins, about 6 mins to about 10 mins, about 7 mins to about 8 mins, about 7 mins to about 9 mins, about 7 mins to about 10 mins, about 8 mins to about 9 mins, about 8 mins to about 10 mins, or about 9 mins to about 10 mins. In some cases, the heat curing is carried out for about 5 mins, about 6 mins, about 7 mins, about 8 mins, about 9 mins, or about 10 mins. In some cases, the heat curing is carried out at a temperature of about 200 ℃ to about 280 ℃. In some cases, the heat curing is carried out at a temperature of at least about 200 ℃. In some cases, the heat curing is carried out at a temperature of at most about 280 ℃. In some cases, the heat curing is carried out at a temperature of about 200 ℃ to about 220 ℃, about 200 ℃ to about 240 ℃, about 200 ℃ to about 260 ℃, about 200 ℃ to about 280 ℃, about 220 ℃ to about 240 ℃, about 220 ℃ to about 260 ℃, about 220 ℃ to about 280 ℃, about 240 ℃ to about 260 ℃, about 240 ℃ to about 280 ℃, or about 260 ℃ to about 280 ℃. In some cases, the heat curing is carried out at a temperature of about 200 ℃, about 220 ℃, about 240 ℃, about 260 ℃, or about 280 ℃.

The above and other aspects, features, and advantages of the present invention will become more apparent upon consideration of the following description of preferred embodiments, taken in conjunction with the accompanying drawing figures.

FIG. 1 shows scanning electron microscope (SEM) analysis results for the spherical graphene powder of Preparation Example 2 and the sheet graphene of Preparation Example 4. Here, Fig. 1A and 1B are the 500x and 2,000x magnification SEM images of the sheet graphene of Preparation Example 4, respectively, while Fig. 1C and 1D are the 500x and 2,000x magnification SEM images of the spherical graphene powder of Preparation Example 2, respectively.

Definitions

While the following terms are believed to be well understood by one of ordinary skill in the art, the following definitions are set forth to facilitate explanation of the presently disclosed subject matter.

As used herein, the term "a" or "an" can refer to one or more of that entity, i.e. can refer to a plural referents. As such, the terms "a" or "an", "one or more" and "at least one" can be used interchangeably herein. In addition, reference to "an element" by the indefinite article "a" or "an" does not exclude the possibility that more than one of the elements is present, unless the context clearly requires that there is one and only one of the elements.

Unless the context requires otherwise, throughout the present specification and claims, the word "comprise" and variations thereof, such as, "comprises" and "comprising" are to be construed in an open, inclusive sense that is as "including, but not limited to".

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification may not necessarily all referring to the same embodiment. It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

Overview

Provided herein are compositions comprising spherical graphene and methods for preparing the compositions. The compositions can be used for coating cookware. Also disclosed herein are methods of coating a cookware using the compositions.

Methods

Provided herein are also methods for preparing a coating compositing. The method can comprise: (i) dispersing graphene oxide in a solvent to form a graphene oxide dispersion; (ii) drying the graphene oxide dispersion to obtain a spherical graphene oxide powder; and (iii) reducing the spherical graphene oxide powder to form a coating compositing.

In some cases, the graphene oxide can be obtained by oxidizing graphite. For example, the method use for preparing the graphene oxide can be the Hummers method (J. A. Chem. Soc. 1958, 80, 1339) or the modified Hummers method (Chem. Mater. 1999, 11(3), 771).

In step (i), the solvent can be water, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), or any combination thereof. In some cases, the method can further comprise mixing a metal salt into the graphene oxide dispersion. The metal salt can bind to the ends of the graphene oxide and/or act as a central point that causes the graphene oxide to clump around the metal salt, inducing aggregation in a 3-dimensional spherical shape. The metal salt can be dissolved in the solvent, such as a metal nitrate salt, so that the metal salt is ionized in the solvent to take on a (+) charge and thereby attract graphene oxide having a (-) charge through electrostatic attraction. The metal salt can be a silver salt, an iron salt, a copper salt, an aluminum salt, a nickel salt, or any combination thereof. The metal salt can also be an acetate salt, a carbonate salt, a chloride salt, a citrate salt, a cyanide salt, a fluoride salt, a nitrate salt, a nitrite salt, a phosphate salt, a sulfate salt, or any combination thereof. The metal salt can be silver acetate, silver carbonate, silver chloride, silver citrate, silver cyanide, silver fluoride, silver nitrate, silver nitrite, silver phosphate, silver sulfate, or any combination thereof. The metal salt can be iron acetate, iron carbonate, iron chloride, iron citrate, iron cyanide, iron fluoride, iron nitrate, iron nitrite, iron phosphate, iron sulfate, or any combination thereof. The metal salt can be copper acetate, copper carbonate, copper chloride, copper citrate, copper cyanide, copper fluoride, copper nitrate, copper nitrite, copper phosphate, copper sulfate, or any combination thereof. The metal salt can be aluminum acetate, aluminum carbonate, aluminum chloride, aluminum citrate, aluminum cyanide, aluminum fluoride, aluminum nitrate, aluminum nitrite, aluminum phosphate, aluminum sulfate, or any combination thereof. The metal salt can be nickel acetate, nickel carbonate, nickel chloride, nickel citrate, nickel cyanide, nickel fluoride, nickel nitrate, nickel nitrite, nickel phosphate, nickel sulfate, or any combination thereof. For example, the metal salt can be aluminum nitrate, copper nitrate, or any combination thereof.

The metal salt and graphene oxide can be mixed at a weight ratio of 1-20 parts of metal salt to 1 part of graphene oxide. The metal salt and graphene oxide can be mixed at a weight ratio of at least about 1:1. The metal salt and graphene oxide can be mixed at a weight ratio of at most about 20:1. The metal salt and graphene oxide can be mixed at a weight ratio of about 1:1 to about 2:1, about 1:1 to about 4:1, about 1:1 to about 6:1, about 1:1 to about 8:1, about 1:1 to about 10:1, about 1:1 to about 15:1, about 1:1 to about 20:1, about 2:1 to about 4:1, about 2:1 to about 6:1, about 2:1 to about 8:1, about 2:1 to about 10:1, about 2:1 to about 15:1, about 2:1 to about 20:1, about 4:1 to about 6:1, about 4:1 to about 8:1, about 4:1 to about 10:1, about 4:1 to about 15:1, about 4:1 to about 20:1, about 6:1 to about 8:1, about 6:1 to about 10:1, about 6:1 to about 15:1, about 6:1 to about 20:1, about 8:1 to about 10:1, about 8:1 to about 15:1, about 8:1 to about 20:1, about 10:1 to about 15:1, about 10:1 to about 20:1, or about 15:1 to about 20:1. The metal salt and graphene oxide can be mixed at a weight ratio of about 1:1, about 2:1, about 4:1, about 6:1, about 8:1, about 10:1, about 15:1, or about 20:1.

In step (ii), the drying can be spray drying. The spray drying can be carried out using an spray drying apparatus, and may be performed with the inlet temperature at 100 to 150 ℃, the outlet at 50 to 70 ℃, for example 60 ℃, and/or the feed rate at 25 to 30 Hz, for example 27 to 28 Hz.

In step (iii), the spherical graphene oxide powder can be reduced by irradiating with microwave radiation in a reducing atmosphere. When reducing through irradiation with microwaves, the oxygen inside the graphene oxide framework can be expelled at a fast rate, causing the adjacent carbons to bind and create a graphene structure without defects. Accordingly, the method can form a spherical graphene powder having a high specific surface area. In some cases, the reducing atmosphere may be formed using hydrogen or a mixed gas of hydrogen and an inert gas. The irradiation with microwaves can be carried out between 30 seconds and 3 minutes at an output of about 700W.

In some cases, the method can further comprise a primary heat treatment process of the spherical graphene oxide powder at 300 to 400 ℃. The primary heat may be carried out in a reducing atmosphere.

Also disclosed herein is a method for coating a heating cookware. The method can comprise (a) dispersing the coating composition using a microfluidizer; (b) applying the dispersed coating composition on a cookware main body, and; (c) heat curing the applied coating composition for the cookware.

Step (a) can further improve the thermal conductivity of a coating layer formed by the heating cookware. The dispersion using a microfluidizer can be performed for about 10 minutes to about 30 minutes. The dispersion using a microfluidizer can be performed for at least about 10 minutes. The dispersion using a microfluidizer can be performed for at most about 30 minutes. The dispersion using a microfluidizer can be performed for about 10 minutes to about 20 minutes, about 10 minutes to about 30 minutes, or about 20 minutes to about 30 minutes. The dispersion using a microfluidizer can be performed for about 10 minutes, about 20 minutes, or about 30 minutes.

In step (b), spray coating can be used as the method for applying the dispersed coating composition for the cookware. In some cases, an additional step of pre-heating the dispersed coating composition for heating cookware may be included between step (a) and step (b). The pre-heating temperature may be 50 to 60 ℃.

In step (c), the heat curing can be carried out using hot air heating, infra-red heating or induction heating methods, and/or can be carried out from 5 to 10 minutes at 200 to 280 ℃.

Compositions

Provided herein are compositions for coating cookware. The composition can comprise a spherical graphene powder having a Brunauer, Emmett and Teller (BET) specific surface area of at least 400 m²/g. The composition can further comprise an inorganic binder and/or a solvent.

The term BET specific surface area refers to the specific surface area determined by the BET theory. For instance, the BET specific surface area can be determined by physical adsorption of a gas on the surface of the solid and by calculating the amount of adsorbate gas corresponding to a monomolecular layer on the surface. Physical adsorption can result from relatively weak forces (van der Waals forces) between the adsorbate gas molecules and the adsorbent surface area of the test powder. The determination can be carried out on a BET instrument (Micromeritics Gemini 2375 and Gemini V). The determination can be performed at the boiling point of liquid nitrogen (-196°C). The amount of gas adsorbed can be correlated to the total surface area of the particles including pores in the surface and can be measured by a volumetric or continuous flow procedure. The BET specific surface area can be determined by nitrogen adsorption according to the ASTMD 3663-78 standard, which is based on the publication [The Journal of the American Chemical Society, 60, 309 (1938)].

The methods disclosed here can produce a spherical graphene powder having a specific surface area of 400 m²/g or greater. The spherical graphene powder can have a spherical shape. The spherical graphene powder can have superior vertical thermal radiation characteristics, and/or can improve the thermal conductivity of a coating layer. Further, the spherical graphene powder can increase the density of a coating layer, improve the durability (wear resistance) of the coating layer, and/or thereby extend the life of heating cookware.

The BET specific surface area of the spherical graphene powder can be about 400 m²/g to about 800 m²/g. The BET specific surface area of the spherical graphene powder can be at least about 400 m²/g. The BET specific surface area of the spherical graphene powder can be at most about 800 m²/g. The BET specific surface area of the spherical graphene powder can be about 400 m²/g to about 500 m²/g, about 400 m²/g to about 600 m²/g, about 400 m²/g to about 700 m²/g, about 400 m²/g to about 800 m²/g, about 500 m²/g to about 600 m²/g, about 500 m²/g to about 700 m²/g, about 500 m²/g to about 800 m²/g, about 600 m²/g to about 700 m²/g, about 600 m²/g to about 800 m²/g, or about 700 m²/g to about 800 m²/g. The BET specific surface area of the spherical graphene powder can be about 400 m²/g, about 500 m²/g, about 600 m²/g, about 700 m²/g, or about 800 m²/g.

In some cases, the inorganic binder can comprise silane compound and silica sol. Silane compounds can comprise methyltrimethoxysilane, ethyltrimethoxysilane, normal propyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, normal propyltriethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, triple fluoropropyl trimethoxysilane, tridecafluorooctyl trimethoxysilane, tetraethoxysilane, heptadecafluorodecyl trimethoxysilane, or any combination thereof.

The composition can further comprise a metal salt. The metal salt can be a silver salt, an iron salt, a copper salt, an aluminum salt, a nickel salt, or any combination thereof. The metal salt can also be an acetate salt, a carbonate salt, a chloride salt, a citrate salt, a cyanide salt, a fluoride salt, a nitrate salt, a nitrite salt, a phosphate salt, a sulfate salt, or any combination thereof. The metal salt can be silver acetate, silver carbonate, silver chloride, silver citrate, silver cyanide, silver fluoride, silver nitrate, silver nitrite, silver phosphate, silver sulfate, or any combination thereof. The metal salt can be iron acetate, iron carbonate, iron chloride, iron citrate, iron cyanide, iron fluoride, iron nitrate, iron nitrite, iron phosphate, iron sulfate, or any combination thereof. The metal salt can be copper acetate, copper carbonate, copper chloride, copper citrate, copper cyanide, copper fluoride, copper nitrate, copper nitrite, copper phosphate, copper sulfate, or any combination thereof. The metal salt can be aluminum acetate, aluminum carbonate, aluminum chloride, aluminum citrate, aluminum cyanide, aluminum fluoride, aluminum nitrate, aluminum nitrite, aluminum phosphate, aluminum sulfate, or any combination thereof. The metal salt can be nickel acetate, nickel carbonate, nickel chloride, nickel citrate, nickel cyanide, nickel fluoride, nickel nitrate, nickel nitrite, nickel phosphate, nickel sulfate, or any combination thereof. For example, the metal salt can be aluminum nitrate, copper nitrate, or any combination thereof.

The silica sol, where silica (SiO₂) powder forms colloid particles in water, may be obtained by dispersing silica (SiO₂) powder with an average particle size of 0.2 to 1.0 μm in water.

In some cases, the solvent can be, but is not limited to, alcohol-based solvents such as isopropyl alcohol, Cellosolve solvents such as butyl Cellosolve, ester-based solvents such as isopropyl acetate, aqueous solvents such as water, ketone-based solvents, amine-based solvents, amide-based solvents, halogenated hydrocarbon solvents, ether-based solvents, and furan-based solvents.

The coating composition can further comprise a 1-dimensional or 2-dimensional structure carbon material having superior horizontal heat radiation characteristics, which can be linear or sheet carbon. The linear or sheet carbon material can be, for example, sheet graphene, graphite, carbon nanotubes, or any combination thereof. The mix ratio of the spherical graphene powder and the linear or sheet carbon material can be 10:90 to 90:10 parts by weight, preferably 40:60 to 60:40.

The coating composition can further comprise additives such as antimicrobial agents, anticorrosive agents, fillers, and pigments.

Also disclosed herein is a cookware. The cookware can comprise a main body, and a cured product of the coating composition formed on the main body. In some cases, the cookware can refer to an apparatus used for cooking with heat, specific examples including but not limited to frying pans, saucepans, pots, kettles and grills, etc. The material of the heating cookware main body can be any material known to the art. Specifically, the material can be iron or steel, stainless steel, copper, aluminum, or ceramic, etc.

EXAMPLES

The present disclosure is further illustrated by reference to the following Examples. However, it should be noted that these Examples, like the embodiments described above, are illustrative and are not to be construed as restricting the scope of the invention in any way.

Preparation Example 1: Preparation of graphene oxide

In this example, 10g graphite, 400mL sulfuric acid (H₂SO₄) and 50g potassium permanganate (KMnO₄) were stirred for 24 hours at under 55℃ to carry out a graphite oxidation reaction. The reaction was ended by adding 50mL 40% hydrogen peroxide to the oxidation reaction product. The reaction product was centrifuged, purified by filtration, and then dried to prepare graphene oxide.

Preparation Example 2: Preparation of spherical graphene powder

In this example, the graphene oxide obtained in Preparation Example 1 was dispersed at 10 g/L in distilled water. To this dispersion, aluminum nitrate as a metal salt was added at a ratio of 100 parts by weight per 100 parts by weight graphene oxide, and mixed by stirring for 1 hour. The mixture was spray-dried with an inlet temperature of 125℃, an outlet of 60℃, and a feed rate of 27Hz to spherical graphene oxide powder.

The spherical graphene oxide powder was subjected to a primary heat treatment process in a rotary kiln at 350℃ for 1 hour with an Ar gas mixture containing 4% H₂, then reduced by irradiating with microwave radiation for 30 seconds to 1 minute at 700W output in a microwave reactor with an Ar gas mixture containing 4% H₂ to prepare a spherical graphene powder.

Preparation Example 3: Preparation of spherical graphene powder

In this example, the graphene oxide obtained in Preparation Example 1 was dispersed at 10 g/L in distilled water. The dispersion was spray-dried with an inlet temperature of 125℃, an outlet of 60℃, and a feed rate of 27 Hz to obtain spherical graphene oxide powder.

Preparation Example 4: Preparation of sheet graphene

In this example, the graphene oxide obtained in Preparation Example 1 was dispersed at 5g/L in distilled water. While stirring the dispersion, 30 parts by weight ascorbic acid was added per 100 parts by weight graphene oxide. The mixture was heated for 1 hour at 90℃. After centrifuging the reaction product for 10 minutes at 7,000 rpm, excess distilled water was used to repeatedly rinse, thereby obtaining sheet graphene.

Preparation Embodiment 1: Preparation of coating composition for heating cookware

In this example, 17 parts by weight isopropyl alcohol and 28 parts by weight distilled water, 22 parts by weight methyl trimethoxysilane, 16 parts by weight tetraethoxysilane, 13 parts by weight silica (SiO₂), 13 parts by weight butyl cellosolve and 1 part by weight of the spherical graphene powder of Preparation Example 2 were added. This mixture was stirred at 300 to 600 rpm. To the stirred mixture, 10 parts by weight ZrO₂ and Al₂O₃ (1:1 mixture) as a filler and 14 parts by weight TiO₂ as a pigment was added. The mixture was stirred using a bead stirrer to prepare the coating composition for the cookware.

Preparation Embodiment 2: Preparation of coating composition for heating cookware

In this example, preparation Embodiment 1 was repeated to prepare a coating composition for the cookware, except that 0.5 parts by weight of the spherical graphene powder of Preparation Example 2 and 0.5 parts by weight carbon nanotube were used instead of 1 part by weight of the spherical graphene powder of Preparation Example 2.

Preparation Embodiment 3: Preparation of coating composition for heating cookware

In this example, preparation Embodiment 1 was repeated to prepare a coating composition for the cookware, except that 0.5 parts by weight of the spherical graphene powder of Preparation Example 2 and 0.5 parts by weight graphite were used instead of 1 part by weight of the spherical graphene powder of Preparation Example 2.

Preparation Embodiment 4: Preparation of coating composition for heating cookware

In this example, preparation Embodiment 1 was repeated to prepare a coating composition for heating cookware, except that the spherical graphene powder of Preparation Example 3 was used instead of the spherical graphene powder of Preparation Example 2.

Comparative Preparation Example 1: Preparation of coating composition for heating cookware

In this example, preparation Embodiment 1 was repeated to prepare a coating composition for the cookware, except that the spherical graphene powder of Preparation Example 2 was not added.

Comparative Preparation Example 2: Preparation of coating composition for heating cookware

In this example, preparation Embodiment 1 was repeated to prepare a coating composition for heating cookware, except that the sheet graphene of Preparation Example 4 was used instead of the spherical graphene powder of Preparation Example 2.

Embodiment 1: Preparation of coated heating cookware

In this example, coating composition for heating cookware of Preparation Embodiment 1 was continuously dispersed for 30 minutes at room temperature using a microfluidizer (M-110-EH, Microfluidics).

After pre-heating the dispersed coating composition for heating cookware to 55℃, it was coated onto the surface of the main body of a frying pan (aluminum). After applying three coats to minimize air pockets in the coating, the coats were thermally cured for 10 minutes at 260℃ to prepare a coated cookware.

Embodiment 2: Preparation of coated heating cookware

In this example, Embodiment 1 was repeated to prepare a coated heating cookware, except that the coating composition for heating cookware of Preparation Example 2 was used instead of the coating composition for heating cookware of Preparation Example 1.

Embodiment 3: Preparation of coated heating cookware

In this example, Embodiment 1 was repeated to prepare a coated heating cookware, except that the coating composition for heating cookware of Preparation Example 3 was used instead of the coating composition for heating cookware of Preparation Example 1.

Embodiment 4: Preparation of coated heating cookware

In this example, Embodiment 1 was repeated to prepare a coated heating cookware, except that the coating composition for heating cookware of Preparation Example 4 was used instead of the coating composition for heating cookware of Preparation Example 1.

Comparative Example 1: Preparation of coated heating cookware

In this example, Embodiment 1 was repeated to prepare a coated heating cookware, except that the coating composition for heating cookware of Comparative Preparation Example 1 was used instead of the coating composition for heating cookware of Preparation Embodiment 1.

Comparative Example 2: Preparation of coated heating cookware

In this example, Embodiment 1 was repeated to prepare a coated heating cookware, except that the coating composition for heating cookware of Comparative Preparation Example 2 was used instead of the coating composition for heating cookware of Preparation Embodiment 1.

Comparative Example 3: Preparation of coated heating cookware

In this example, the coating composition for heating cookware of Preparation Embodiment 1 was dispersed through ultrasonic treatment for 1 hour at room temperature using an ultrasonic homogenizer (Power sonic 410, Hwashin Tech).

After pre-heating the dispersed coating composition for heating cookware to 55℃, it was coated onto the surface of the main body of a frying pan (aluminum). After applying three coats to minimize air pockets in the coating, the coats were thermally cured for 10 minutes at 260℃ to prepare a coated heating cookware.

Comparative Example 4: Preparation of coated heating cookware

In this example, the coating composition for heating cookware of Preparation Embodiment 1 was dispersed for 1 hour at room temperature and 5,000 rpm using a homogenizer (L5, Silverson).

Experimental Example 1: Analysis of the shape of the spherical graphene powder

In this example, the shape of the spherical graphene powder of Preparation Example 2 and the sheet graphene of Preparation Example 4 were analyzed through a scanning electron microscope (SEM).

The results are shown in Fig. 1. In Fig. 1, a and b are the 500x and 2,000x magnification SEM images of the sheet graphene of Preparation Example 4, respectively, while c and d are the 500x and 2,000x magnification SEM images of the spherical graphene powder of Preparation Example 2, respectively.

Fig. 1 shows that whereas the sheet graphene of Preparation Example 4 has a 2-dimensional sheet shape, the spherical graphene powder of Preparation Example 2 has a 3-dimensional spherical shape.

Experimental Example 2: Analysis of BET specific surface area of carbon material

In this example, the BET specific surface area of the carbon materials were measured using a specific surface area measuring apparatus (BELSORP Mini II). The results are shown in Table 1 below.

	BET Specific Surface Area (m²/g)
Preparation Example 2	690
Preparation Example 3	780
Preparation Example 4	280
Carbon Nanotube	230
Graphite	3

Experimental Example 3: Thermal conductivity evaluation

In this example, the thermal conductivity of the heating cookwares prepared in the above embodiments and comparative examples were measured using the method indicated below, and the results are shown in Table 2 below.

At an ambient indoor temperature of 25℃, the same amount (500ml) of water was added to the respective heating cookwares, which were heated at same output level (High) on gas burners (MS-2500, Max). The temperature of the water was measured over time. The

Time(sec)	Water Temperature (℃)
Time(sec)	Emb. 1	Emb. 2	Emb. 3	Emb. 4	Comp. Ex. 1	Comp. Ex. 2	Comp. Ex. 3	Comp. Ex. 4
160	79.2	81.5	81.0	80.1	75.3	81.3	76.9	78.5
170	81.9	84.2	83.8	81.9	77.7	83.7	78.6	80.2
180	85.9	88.9	88.1	85.8	79.8	85.8	83.2	84.1
190	88.8	90.4	89.9	88.0	81.7	87.4	86.3	86.9
200	90.7	92.7	92.4	90.4	84.3	89.3	88.5	89.9
210	92.6	94.8	94.1	91.1	86.6	90.8	89.7	90.6

Experimental Example 4: Durability (wear resistance) evaluation

In this example, the durability of the heating cookwares prepared in Embodiment 1 and Comparative Example 1 was measured using the method indicated below.

A scrubber (AL-345, 3M) was mounted on an abrasion tester (fabricated in-house according to ASTM standards; Samyang Gear Max Geared Motor #88), and the surfaces of the coating layers of the heating cookwares were scrubbed at 60 repetitions per minute and a load of 1.8kg. After 1,000 repetitions, the scrubber was replaced with a new product.

In the results, scratches formed on the heating cookware prepared in Embodiment 1 after approximately 24,000 scrubs. On the other hand, scratches formed on the heating cookware prepared in Comparative Example 1 after approximately 12,000 scrubs.

Accordingly, it was found that the durability (wear resistance) of the heating cookware prepared in Embodiment 1 was around twice as good as that of the heating cookware prepared in Comparative Example 1.

The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent application, foreign patents, foreign patent application and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, application and publications to provide yet further embodiments.

These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.

INCORPORATION BY REFERENCE

All references, articles, publications, patents, patent publications, and patent applications cited herein are incorporated by reference in their entireties for all purposes. However, mention of any reference, article, publication, patent, patent publication, and patent application cited herein is not, and should not be taken as an acknowledgment or any form of suggestion that they constitute valid prior art or form part of the common general knowledge in any country in the world.

The various modes for the present invention are described in the above Best Mode.

The present invention has an industrial applicability, because the present invention can be applied to cookware, etc., as discussed above.

Claims

A composition comprising: a spherical graphene powder comprising a Brunauer, Emmett and Teller (BET) specific surface area of at least about 400 m²/g.
The composition of claim 1, wherein said BET specific surface area is from about 400 m²/g to about 800 m²/g.
The composition of claim 1 or 2, wherein said BET specific surface area is at least 20% larger than a corresponding carbon nanotube powder.
The composition of any one of claim 1 to 3, wherein said spherical graphene powder comprises at least 50% (w/w) of said composition.
The composition of any one of claims 1 to 4, further comprising an inorganic binder.
The composition of claim 5, wherein said inorganic binder comprises a silane compound, a silica sol, or both.
The composition of claim 6, wherein said silane compound comprises methyltrimethoxysilane, ethyltrimethoxysilane, normal propyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, normal propyltriethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, triple fluoropropyl trimethoxysilane, tridecafluorooctyl trimethoxysilane, tetraethoxysilane, heptadecafluorodecyl trimethoxysilane, or any combination thereof.
The composition of claim 6 or 7, wherein said silica sol comprises a silica powder with an average particle size of 0.2 to 1.0 μm.
The composition of claim 8, wherein said silica powder is dispersed in water.
The composition of any one of claims 1 to 9, further comprising a solvent.
The composition of claim 10, wherein said solvent comprises water, an alcohol-based solvent, a Cellsolve solvent, an ester-based solvent, an aqueous solvent, a ketone-based solvent, an amine-based solvent, an amide-based solvent, a halogenated hydrocarbon solvent, an ether-based solvent, a furan-based solvent, or any combination thereof.
The composition of claim 11, wherein said solvent is water, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), or any combination thereof.
The composition of any one of claims 1 to 12, further comprising a metal salt.
The composition of claim 13, where said metal salt comprises a silver salt, an iron salt, a copper salt, an aluminum salt, a nickel salt, or any combination thereof.
The composition of claim 13, where said metal salt comprises an acetate salt, a carbonate salt, a chloride salt, a citrate salt, a cyanide salt, a fluoride salt, a nitrate salt, a nitrite salt, a phosphate salt, a sulfate salt, or any combination thereof.
The composition of claim 13, wherein said metal salt comprises aluminum nitrate, copper nitrate, or any combination thereof.
The composition of any one of claims 1 to 16, further comprising graphene oxide.
The composition of claim 17, wherein said metal salt and graphene oxide has a weight ratio of at least about 1:1.
The composition of claim 18, wherein said weight ratio is about 1:1 to about 20:1.
The composition of any one of claims 1 to 19, further comprising a linear or sheet carbon material.
The composition of claim 20, wherein said linear or sheet carbon material comprises sheet graphene, graphite, carbon nanotubes, or any combination thereof.
The composition of claim 21, wherein said spherical graphene powder and said linear or sheet carbon material has a weight ratio of about 1:9 to about 9:1.
The composition of claim 21 or 22, wherein said weight ratio is about 4:6 to about 6:4.
The composition of any one of claims 1 to 23, further comprising an additive.
The composition of claim 24, wherein said additive comprises an antimicrobial agent, an anticorrosive agent, a filler, a pigment, or any combination thereof.
The composition of any one of claims 1 to 25, wherein said composition is a coating composition.
A cookware, comprising a heating cookware main body, and a cured product of said composition of any one of claims 1 to 26 formed on said heating cookware main body.
The cookware of claim 27, comprising a frying pan, a saucepan, a pot, a kettle, or a grill.
The cookware of claim 27 or 28, wherein said heating cookware main body comprises iron, steel, stainless steel, copper, aluminum, ceramic, or any combination thereof.
A method for preparing a compositing, comprising:

(i) dispersing graphene oxide in a solvent to form a graphene oxide dispersion;

(ii) drying said graphene oxide dispersion to obtain a spherical graphene oxide powder; and

(iii) reducing said spherical graphene oxide powder to form said compositing.
The method of claim 30, further comprising oxidizing graphite to form said graphene oxide.
The method of claim 31, further comprising oxidizing graphite using the Hummers method or the modified Hummers method.
The method of any one of claims 30 to 32, wherein said solvent comprises water, an alcohol-based solvent, a Cellsolve solvent, an ester-based solvent, an aqueous solvent, a ketone-based solvent, an amine-based solvent, an amide-based solvent, a halogenated hydrocarbon solvent, an ether-based solvent, a furan-based solvent, or any combination thereof.
The method of claim 33, wherein said solvent is water, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), or any combination thereof.
The method of any one of claims 30 to 34, further comprising mixing a metal salt with said graphene oxide dispersion.
The method of claim 35, where said metal salt comprises a silver salt, an iron salt, a copper salt, an aluminum salt, a nickel salt, or any combination thereof.
The method of claim 35, where said metal salt comprises an acetate salt, a carbonate salt, a chloride salt, a citrate salt, a cyanide salt, a fluoride salt, a nitrate salt, a nitrite salt, a phosphate salt, a sulfate salt, or any combination thereof.
The method of claim 35, wherein said metal salt comprises aluminum nitrate, copper nitrate, or any combination thereof.
The method of any one of claims 35 to 38, wherein said metal salt and graphene oxide has a weight ratio of at least about 1:1.
The method of claim 39, wherein said weight ratio is about 1:1 to about 20:1.
The method of any one of claim 30 to 40, further comprising adding an inorganic binder to said graphene oxide dispersion.
The method of claim 41, wherein said inorganic binder comprises a silane compound, a silica sol, or both.
The method of claim 42, wherein said silane compound comprises methyltrimethoxysilane, ethyltrimethoxysilane, normal propyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, normal propyltriethoxysilane, phenyltriethoxysilane, vinyltriethoxysilane, triple fluoropropyl trimethoxysilane, tridecafluorooctyl trimethoxysilane, tetraethoxysilane, heptadecafluorodecyl trimethoxysilane, or any combination thereof.
The method of claim 42 or 43, wherein said silica sol comprises a silica powder with an average particle size of 0.2 to 1.0 μm.
The method of any one of claims 44, wherein said silica powder is dispersed in water.
The method of any one of claims 30 to 45, wherein said drying comprises spray drying.
The method of any one of claims 30 to 46, wherein said drying is performed with an inlet temperature at 100 to 150 ℃, an outlet temperature at 50 to 70 ℃, a feed rate at 25 to 30 Hz, or any combination thereof.
The method of any one of claims 30 to 47, wherein said reducing said spherical graphene oxide powder comprises irradiating said spherical graphene oxide powder with microwave radiation.
The method of claim 48, wherein said irradiating said spherical graphene oxide powder is performed in a reducing atmosphere.
The method of claim 48 or 49, wherein said irradiating said spherical graphene oxide powder is carried out between 30 seconds and 3 minutes.
The method of any one of claims 48 to 50, wherein said irradiating said spherical graphene oxide powder is carried out at an output of about 700W.
The method of any one of claims 30 to 51, further comprising heating said spherical graphene oxide powder.
The method of claim 51, wherein said heating said spherical graphene oxide powder is carried out at 300 to 400 ℃.
The method of claim 51 or 53, wherein said heating said spherical graphene oxide powder is carried out in a reducing atmosphere.
A method for coating a cookware, comprising:

(a) applying said composition of any one of claims 1-29 or said composition prepared by method of any one of claims 30-54 on a cookware main body; and

(b) heat curing said composition on said cookware main body.
The method of claim 55, further comprising applying a thermal conductive layer on said cookware main body.
The method of claim 55 or 56, further comprising dispersing said composition prior to applying said composition.
The method of claim 57, wherein said dispersing said composition is performed using a microfluidizer.
The method of claim 57 or 58, wherein said dispersing said composition is performed for about 10 minutes to about 30 minutes.
The method of any one of claims 55 to 59, wherein said applying said composition is spray coating.
The method of any one of claims 55 to 60, further comprising pre-heating said composition prior to applying said composition.
The method of claim 61, comprising pre-heating said composition to about 50 to 60 ℃.
The method of any one of claims 54 to 62, wherein said heat curing is carried out using hot air heating, infra-red heating, or induction heating.
The method of any one of claims 54 to 63, wherein said heat curing is carried out for 5 to 10 minutes.
The method of any one of claims 54 to 64, wherein said heat curing is carried out at 200 to 280 ℃.