# US 11,441,050 B2 · Electromagnetic shielding filler, electromagnetic shielding coating comprising the same, preparation method and use thereof

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,441,050 B2
- Document ID: US11441050B2
- Status: Granted
- Kind: B2
- Application number: 16/765,841
- Filed: 2018-10-11
- Published: 2021-04-29
- Granted: 2022-09-13
- Earliest claimed: 2017-12-08
- Assignees: Crrc Qingdao Sifang Co., Ltd.
- Applicants: Crrc Qingdao Sifang Co., Ltd.
- Inventors: Lin Sun; Yue Xu; Yuming Feng; Peng Lin; Sansan Ding
- Web page: https://patentgrep.com/patent/US11441050B2

## CPC

- C09D 151/06: grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
- H05K 9/0092: {comprising electro-conductive pigments, e.g. paint, ink, tampon printing}
- C08G 18/4009: {Two or more macromolecular compounds not provided for in one single group of groups C08G18/42 - C08G18/64}
- C08G 18/42: Polycondensates having carboxylic or carbonic ester groups in the main chain
- C08G 18/6279: {containing fluorine atoms}
- C08G 18/792: {formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates}
- C08J 3/203: {Solid polymers with solid and/or liquid additives}
- C08K 3/042: {Graphene or derivatives, e.g. graphene oxides}
- C08K 3/22: of metals
- C09D 127/12: containing fluorine atoms
- C09D 175/04: Polyurethanes
- H05K 9/0081: {Electromagnetic shielding materials, e.g. EMI, RFI shielding (H05K9/0003 takes precedence)}
- H05K 9/0083: {comprising electro-conductive non-fibrous particles embedded in an electrically insulating supporting structure, e.g. powder, flakes, whiskers (H05K9/0086 takes precedence)}
- C08J 2379/02: Polyamines
- C08K 2003/2265: {of iron}
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

The present invention relates to a shielding filler, a shielding coating comprising the same, a preparation method and a use thereof. The shielding filler adopts melamine sponge as a carrier and surfaces thereof are covered with FeOx/graphene. The electromagnetic shielding coating is formed by mixing a component A and a component B in a molar ratio of (—OH)A:(—NCO)B=1:1, in which component A comprises fluorocarbon resin, elastic polyester resin, an electromagnetic filler, an auxiliary agent and a mixing solvent, and component B is isocyanate. The shielding filler of the present invention has a sponge-like macroporous structure, the pore wall surfaces of which are covered with ferrite and graphene, and the shielding filler has excellent electromagnetic shielding performance due to the electrical loss and magnetic loss. The obtained electromagnetic shielding coating layer is electrically conductive and magnetically inductive and has a broad electromagnetic shielding response frequency band. The obtained electromagnetic shielding coating layer has a low density, which is in line with the development trend of lightweight. The coating is convenient to use, and can be applied by brush coating, spray coating, or roller coating.

## Claims

### Claim 1

A shielding filler, wherein, the shielding filler adopts melamine sponge as a carrier and surfaces thereof are covered with FeOx/graphene;
wherein, the FeOx exists in the following forms: one or more of Fe, FeO, Fe2O3 or Fe3O4;
the FeOx accounts for 5% to 99% of the total mass of the shielding filler, and the graphene accounts for 1% to 95% of the total mass of the shielding filler.

### Claim 2 (depends on 1)

The shielding filler according to claim 1, wherein, the shielding filler has a porosity of 65% to 85%, a saturation magnetization of 86 to 95 emu/g, a coercive force of 158 to 210 Oe, and a response frequency band of 100 kHz to 18 GHz.

### Claim 3

A preparation method of a shielding filler, wherein, the method comprises the following steps:
(1) preparing an aqueous dispersion solution of Fe3+-graphene oxide;
(2) impregnating the melamine sponge with the Fe3+-graphene oxide solution to adsorb the Fe3+-graphene oxide solution, oven drying; and
(3) subjecting the melamine sponge to high temperature treatment;
preferably, step (1) specifically comprises the following steps: adding an iron salt into an aqueous dispersion solution of graphene oxide, and controlling the concentration of Fe3+ to be 5 mg/ml to 500 mg/ml;
and/or, the concentration of the aqueous dispersion solution of graphene oxide is 0.5 mg/ml to 5 mg/ml, preferably 1.0 to 5.0 mg/ml;
and/or, the iron salt is one or more selected from Fe(NO3)3, FeCl3, Fe2(SO4)3, and iron acetate;
preferably, in step (3), the Fe3+-graphene oxide/melamine sponge obtained in step (2) is heated to 300° C. to 1200° C. for heat treatment, ground and sieved to obtain an FeOx/graphene electromagnetic shielding filler; the heat treatment temperature is preferably 500 to 800° C.;
and/or, the heating rate is 1 to 20° C./min, more preferably 5 to 10° C./min.

### Claim 4 (depends on 1)

A preparation method of electromagnetic shielding material for trains, aircrafts, ships or transformers, wherein the method comprises: using the shielding filler according to claim 1.

### Claim 5 (depends on 1)

A shielding coating, which is formed by mixing a component A and a component B in a molar ratio of (—OH)A:(—NCO)B=1:1, wherein, the component A is prepared from the following raw materials in parts by weight: 25 to 55 parts of fluorocarbon resin, 5 to 25 parts of elastic polyester resin, 20 to 30 parts of the shielding filler according to claim 1, 1.5 to 4 parts of auxiliary agent, and 5 to 10 parts of mixed solvent; and
the component B is isocyanate.

### Claim 6 (depends on 5)

The shielding coating according to claim 5, wherein, the fluorocarbon resin is an ethylene polymer grafted with fluorine atoms; preferably GK570, polychlorotrifluoroethylene/vinyl ether resin (FEVE);
and/or, the elastic polyester resin is an elastic polyester modified acrylic resin, and molecular formula of the elastic polyester modified acrylic resin contains irregular polyols with a high relative molecular mass and long-chain fatty acids; preferably, the elastic polyester resin is FTH elastic resin.

### Claim 7 (depends on 5)

The shielding coating according to claim 5, wherein, the auxiliary agent is one or more selected from defoaming agent, leveling agent, dispersant agent or thixotropic agent;
preferably, the defoaming agent is selected from BYK-530A, BYK110 or Deuchem 6800;
and/or, the leveling agent is selected from BYK-320, EFKA3777 or EFKA-2022;
and/or, the thixotropic agent is one or more selected from polyamide wax, organic bentonite or fumed silica;
and/or, the mixed solvent consists of xylene, ethyl acetate, and cyclohexanone in a mass ratio of (2.0 to 5.0):(1.5 to 4.0):(2.5 to 6.0).

### Claim 8 (depends on 5)

The preparation method of the shielding coating according to claim 5, wherein, the method comprises the following steps:
(1) adding the fluorocarbon resin, elastic polyester resin, and auxiliary agent into 2/3 of the mixed solvent, mixing and stirring, slowly adding the electromagnetic shielding filler, dispersing evenly, then grinding to a fineness of 40 μm, adding the remaining mixed solvent, adjusting the system viscosity to 800 to 1000 cp, filtering and discharging to obtain component A; and
(2) mixing the component A and component B, and stirring uniformly to prepare the electromagnetic shielding coating.

### Claim 9 (depends on 5)

A preparation method of an electronic device in the fields of rail vehicles, aircrafts, ships or transformers, wherein the method comprises: using the shielding coating according to claim 5.

### Claim 10 (depends on 5)

An electronic device, wherein, the electronic device comprises the coating layer prepared from the shielding coating according to claim 5.