# US 10,479,050 B2 · Method of preparing conductive magnetic composite sheet and antenna device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,479,050 B2 - Document ID: US10479050B2 - Status: Granted - Kind: B2 - Application number: 15/609,100 - Filed: 2017-05-31 - Published: 2017-11-30 - Granted: 2019-11-19 - Earliest claimed: 2016-05-31 - Assignees: Skc Co., Ltd. - Applicants: Skc Co., Ltd. - Inventors: Tae Kyoung Kim; Jong Hwi Park; Jin Cheol Kim; Hyun Gon Moon; Jonghak Choi; Nah Young Kim - Web page: https://patentgrep.com/patent/US10479050B2 ## CPC - B32B 7/12: using interposed adhesives or interposed materials with bonding properties - B32B 5/16: characterised by features of a layer formed of particles, e.g. chips, powder {or granules (layer formed of natural mineral particles B32B19/00; layer being formed of wood fibres, chips or particles B32B21/02)} - B32B 15/08: of synthetic resin - B32B 15/16: next to a particulate layer - B32B 15/20: comprising aluminium or copper {(B32B15/016 and B32B15/017 take precedence)} - B32B 27/20: using fillers, pigments, thixotroping agents - B32B 27/40: comprising polyurethanes - H01Q 1/242: {specially adapted for hand-held use} - H01Q 1/36: Structural form of radiating elements, e.g. cone, spiral, umbrella; {Particular materials used therewith}(H01Q1/08, H01Q1/14 take precedence) - H01Q 7/06: with core of ferromagnetic material (H01Q7/02 takes precedence) - H02J 50/12: of the resonant type - B32B 37/06: characterised by the heating method - B32B 37/10: characterised by the pressing technique, e.g. using action of vacuum or fluid pressure - B32B 37/18: involving the assembly of discrete sheets or panels only - B32B 37/20: involving the assembly of continuous webs only - B32B 2038/0076: {Curing, vulcanising, cross-linking} - B32B 2250/03: 3 layers - B32B 2250/40: Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA - B32B 2255/06: on metal layer - B32B 2255/26: Polymeric coating - B32B 2260/025: Particulate layer - B32B 2260/046: Synthetic resin - B32B 2264/102: Oxide or hydroxide - B32B 2264/105: Metal - B32B 2264/107: Ceramic - B32B 2264/12: Mixture of at least two particles made of different materials - B32B 2307/202: Conductive - B32B 2307/208: Magnetic, paramagnetic - B32B 2307/732: Dimensional properties - B32B 2375/00: Polyureas; Polyurethanes - B32B 2457/00: Electrical equipment - H04B 5/26: using coils - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - H04B: TRANSMISSION ## Abstract According to a method of preparing a conductive magnetic composite sheet, the method comprising preparing a magnetic sheet comprising a magnetic powder and a binder resin; stacking the magnetic sheet and a first conductive foil; and applying heat and pressure to the obtained stack to bond the magnetic sheet and the first conductive foil, a conductive magnetic composite sheet having excellent interlayer adhesion between the magnetic sheet and the conductive foil can be prepared while having an excellent magnetic property at NFC, WPC, and MST frequencies. ## Claims ### Claim 1 A method of preparing a conductive magnetic composite sheet, the method comprising: preparing a magnetic sheet comprising a magnetic powder and a binder resin; stacking the magnetic sheet and a first conductive foil; and applying heat and pressure to the obtained stack to bond the magnetic sheet and the first conductive foil, wherein the magnetic sheet comprises 70 wt % to 90 wt % of the magnetic powder, and 6 wt % to 12 wt % of a polyurethane-based resin, 0.5 wt % to 2 wt % of an isocyanate-based hardener, and 0.3 wt % to 1.5 wt % of an epoxy-based resin, as the binder resin, based on the total weight of the magnetic sheet. ### Claim 2 (depends on 1) The method of claim 1, wherein the step of applying heat and pressure to the stack is performed at a pressure of 5 MPa to 30 MPa and a temperature of 150° C. to 200° C. ### Claim 3 (depends on 1) The method of claim 1, wherein the stacking step and the step of applying heat and pressure to the stack are performed by a roll-to-roll process, which is performed at a roll temperature of 150° C. to 200° C., a roll pressure of 5 MPa to 30 MPa, and a speed of 1 m/min to 5 m/min by using 2 to 10 pairs of rolls. ### Claim 4 (depends on 1) The method of claim 1, wherein the magnetic sheet is an unsintered sheet with a thickness of 10 μm to 3,000 μm having flexibility. ### Claim 5 (depends on 1) The method of claim 1, wherein the magnetic sheet has a magnetic permeability of 100 to 300 when measured during applying an alternating current with a frequency of 3 MHz to the magnetic sheet, a magnetic permeability of 80 to 270 when measured during applying an alternating current with a frequency of 6.78 MHz to the magnetic sheet, and a magnetic permeability of 60 to 250 when measured during applying an alternating current with a frequency of 13.56 MHz to the magnetic sheet. ### Claim 6 (depends on 1) The method of claim 1, wherein the conductive magnetic composite sheet has a peel strength between the magnetic sheet and the first conductive foil of 0.6 kgf/cm or more after subjected to heat-treatment twice, the heat-treatment including heating from 30° C. to 240° C. at a constant rate for 200 seconds and then cooling from 240° C. to 130° C. at a constant rate for 100 seconds. ### Claim 7 (depends on 1) The method of claim 1, wherein the binder resin is a thermosetting resin, and the binder resin bonds the magnetic sheet to the first conductive foil while being cured in the step of applying heat and pressure to the stack. ### Claim 8 (depends on 7) The method of claim 7, wherein the conductive magnetic composite sheet has a peel strength between the magnetic sheet and the first conductive foil of 0.6 kgf/cm or more after subjected to heat-treatment twice, the heat-treatment including heating from 30° C. to 240° C. at a constant rate for 200 seconds and then cooling from 240° C. to 130° C. at a constant rate for 100 seconds, wherein the magnetic sheet is an unsintered sheet with a thickness of 10 μm to 3,000 μm having flexibility, and the magnetic sheet has a magnetic permeability of 100 to 300 when measured during applying an alternating current with a frequency of 3 MHz to the magnetic sheet; a magnetic permeability of 80 to 270 when measured during applying an alternating current with a frequency of 6.78 MHz to the magnetic sheet; a magnetic permeability of 60 to 250 when measured during applying an alternating current with a frequency of 13.56 MHz to the magnetic sheet; a thickness change of 5% or less and a magnetic permeability change of 5% or less after subjected to heat-treatment twice, the heat-treatment being composed of heating from 30° C. to 240° C. at a constant rate for 200 seconds and then cooling from 240° C. to 130° C. at a constant rate for 100 seconds; a thickness change of 5% or less and a magnetic permeability change of 5% or less after immersed in a 2 N hydrochloric acid solution for 30 minutes; and a thickness change of 5% or less and a magnetic permeability change of 5% or less after immersed in a 2 N sodium hydroxide solution for 30 minutes. ### Claim 9 (depends on 1) The method of claim 1, wherein the first conductive foil has a first primer layer formed on its one side, and the magnetic sheet and the first conductive foil are stacked such that one side of the magnetic sheet is in contact with the first primer layer of the first conductive foil. ### Claim 10 (depends on 9) The method of claim 9, wherein the first primer layer has a thickness of 0.01 μm to 1 μm. ### Claim 11 (depends on 9) The method of claim 9, wherein the first primer layer comprises a thermosetting resin, and the thermosetting resin in the first primer layer is cured in the step of applying heat and pressure to the stack. ### Claim 12 (depends on 11) The method of claim 11, wherein the thermosetting resin comprises a bisphenol A-type epoxy resin, a cresol novolac-type epoxy resin, or a tetrakis(glycidyloxyphenyl)ethane-type epoxy resin. ### Claim 13 A method of preparing a conductive magnetic composite sheet, the method comprising: preparing a magnetic sheet comprising a magnetic powder and a binder resin; stacking a first conductive foil, the magnetic sheet and a second conductive foil; and applying heat and pressure to the obtained stack to bond the first conductive foil, the magnetic sheet and the second conductive foil together, wherein the magnetic sheet comprises 70 wt % to 90 wt % of the magnetic powder, and 6 wt % to 12 wt % of a polyurethane-based resin, 0.5 wt % to 2 wt % of an isocyanate-based hardener, and 0.3 wt % to 1.5 wt % of an epoxy-based resin, as the binder resin, based on the total weight of the magnetic sheet. ### Claim 14 (depends on 13) The method of claim 13, wherein the binder resin is a thermosetting resin, and the binder resin bonds the first conductive foil, the magnetic sheet and the second conductive foil together while being cured in the step of applying heat and pressure to the stack. ### Claim 15 (depends on 13) The method of claim 13, wherein the first conductive foil has a first primer layer formed on its one side, the second conductive foil has a second primer layer formed on its one side, the magnetic sheet and the first conductive foil are stacked such that one side of the magnetic sheet is in contact with the first primer layer of the first conductive foil, the magnetic sheet and the second conductive foil are stacked such that the other side of the magnetic sheet is in contact with the second primer layer of the second conductive foil, the first primer layer and the second primer layer comprise a thermosetting resin, and the thermosetting resins in the first and second primer layers are cured in the step of applying heat and pressure to the stack. ### Claim 16 A method of preparing an antenna device, the method comprising: preparing a magnetic sheet comprising a magnetic powder and a binder resin; stacking the magnetic sheet and a first conductive foil; applying heat and pressure to the obtained stack to bond the magnetic sheet and the first conductive foil; and etching the first conductive foil to form an antenna pattern therein, wherein the magnetic sheet comprises 70 wt % to 90 wt % of the magnetic powder, and 6 wt % to 12 wt % of a polyurethane-based resin, 0.5 wt % to 2 wt % of an isocyanate-based hardener, and 0.3 wt % to 1.5 wt % of an epoxy-based resin, as the binder resin, based on the total weight of the magnetic sheet. ### Claim 17 (depends on 16) The method of claim 16, wherein the binder resin is a thermosetting resin, and the binder resin bonds the magnetic sheet and the first conductive foil while being cured in the step of applying heat and pressure to the stack. ### Claim 18 (depends on 16) The method of claim 16, wherein the first conductive foil has a first primer layer formed on its one side, the magnetic sheet and the first conductive foil are stacked such that one side of the magnetic sheet is in contact with the first primer layer of the first conductive foil, the first primer layer comprises a thermosetting resin, and the thermosetting resin in the first primer layer is cured in the step of applying heat and pressure to the stack. ### Claim 19 (depends on 16) The method of claim 16, wherein the magnetic sheet is an unsintered sheet with a thickness of 10 μm to 3,000 μm having flexibility, and the magnetic sheet has a magnetic permeability of 100 to 300 when measured during applying an alternating current with a frequency of 3 MHz to the magnetic sheet; a magnetic permeability of 80 to 270 when measured during applying an alternating current with a frequency of 6.78 MHz to the magnetic sheet; a magnetic permeability of 60 to 250 when measured during applying an alternating current with a frequency of 13.56 MHz to the magnetic sheet; a thickness change of 5% or less and a magnetic permeability change of 5% or less after subjected to heat-treatment twice, the heat-treatment including heating from 30° C. to 240° C. at a constant rate for 200 seconds and then cooling from 240° C. to 130° C. at a constant rate for 100 seconds; a thickness change of 5% or less and a magnetic permeability change of 5% or less after immersed in a 2 N hydrochloric acid solution for 30 minutes; and a thickness change of 5% or less and a magnetic permeability change of 5% or less after immersed in a 2 N sodium hydroxide solution for 30 minutes.