# US 2025/0144918 A1 · Magnetic shield sheet > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0144918 A1 - Document ID: US20250144918A1 - Status: Published application - Kind: A1 - Application number: 18/904,483 - Filed: 2024-10-02 - Published: 2025-05-08 - Earliest claimed: 2023-10-03 - Assignees: Proterial, Ltd. - Applicants: Proterial, Ltd. - Inventors: Hisayuki Miura; Hirotaka Satake - Web page: https://patentgrep.com/patent/US20250144918A1 ## CPC - B32B 15/088: comprising polyamides - H01F 1/15333: {containing nanocrystallites, e.g. obtained by annealing} - B32B 7/12: using interposed adhesives or interposed materials with bonding properties - H01F 1/15308: {based on Fe/Ni (H01F1/15325 takes precedence)} - H01F 1/15383: {Applying coatings thereon (H01F1/15366 takes precedence)} - H05K 9/0075: {Magnetic shielding materials} - B32B 15/18: comprising iron or steel {(B32B15/011, B32B15/012 and B32B15/013 take precedence)} - B32B 2250/03: 3 layers - B32B 2250/40: Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA - B32B 2307/208: Magnetic, paramagnetic - B32B 2307/7376: Thickness - B32B 2311/30: Iron, e.g. steel - B32B 2377/00: Polyamides - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract Provided is a magnetic shield sheet in which deterioration in appearance and degradation in magnetic properties are suppressed even when used in a high-temperature environment. A magnetic shield sheet is a laminated body including a first resin layer, a first adhesive layer, a magnetic layer, a second adhesive layer, and a second resin layer in this order. The magnetic layer is a magnetic layer containing a magnetic material having a magnetostriction constant λ of 30 or less and a thickness from 8-25 μm, the first and second resin layers are resin layers having a melting sublimation point of 250° C. or higher and thickness of 1-24 μm, and the first and second adhesive layers are adhesive layers containing having a melting point of 150° C. or higher and thickness of from 1 μm to 10 μm. ## Claims ### Claim 1 A magnetic shield sheet comprising a laminated body having a first resin layer, a first adhesive layer, a magnetic layer, a second adhesive layer, and a second resin layer in this order, wherein: the magnetic layer contains a magnetic material having a magnetostriction constant λ of 30×10−6 or less, the magnetic layer having a thickness of from 8 μm to 25 μm, each of the first resin layer and the second resin layer contains a resin having a melting point or a sublimation point of 250° C. or higher, and has a thickness of from 1 μm to 24 μm, and each of the first adhesive layer and the second adhesive layer contains an adhesive having a melting point of 150° C. or higher, and has a thickness of from 1 μm to 10 μm. ### Claim 2 (depends on 1) The magnetic shield sheet according to claim 1, wherein: the magnetic layer is an elongated body having a width of from 30 mm to 500 mm, each of the first resin layer, the first adhesive layer, the second adhesive layer, and the second resin layer has a width of 300 mm or more, and a plurality of the magnetic layers are arranged in parallel in a longitudinal direction of the elongated body on a surface of the first adhesive layer at an opposite side from a side having the first resin layer. ### Claim 3 (depends on 1) The magnetic shield sheet according to claim 1, wherein a total thickness of the laminated body is from 33 μm to 65 μm. ### Claim 4 (depends on 1) The magnetic shield sheet according to claim 1, configured in a wound roll shape. ### Claim 5 (depends on 1) The magnetic shield sheet according to claim 1, wherein the magnetic shield sheet is a magnetic shield member obtained by punching the laminated body into any given shape. ### Claim 6 (depends on 1) The magnetic shield sheet according to claim 1, wherein: the first adhesive layer and the second adhesive layer contain a thermosetting adhesive, when an area change rate of at least one of the first resin layer or the second resin layer between before and after heating at a temperature for curing the thermosetting adhesive is A %, and a thickness of each of the first resin layer and the second resin layer is B μm, a product of A and B is 30%·μm or less, a method of measuring the area change rate is such that, in accordance with JIS C 2151:2019, ASTM DD1204, a sample is prepared by cutting out a resin film configuring the first resin layer and the second resin layer to a size of 100 mm×100 mm, the obtained sample of the resin film is heated in a heat treatment furnace under a condition of 200° C.×10 min or 150° C.×30 min according to the temperature for curing the thermosetting adhesive, thermal shrinkage rates in a width direction and a length direction of the resin film before and after the heating are measured by the following method, an area is calculated from the product of the obtained width and length, and an area change rate is measured by the following Formula (a): area ⁢ change ⁢ rate ⁢ ( % ) = absolute ⁢ value ⁢ of [ area ⁢ of ⁢ resin ⁢ film ⁢ before ⁢ heating - area ⁢ of ⁢ resin ⁢ film ⁢ after ⁢ heating ] / area ⁢ of ⁢ resin ⁢ film ⁢ before ⁢ heating , and ⁢ a ⁢ method ⁢ of ⁢ measuring ⁢ thermal ⁢ shrinkage ⁢ rate ⁢ is ⁢ such ⁢ that Formula ⁢ ( a ) (1) a size in the width direction and a size in the length direction of a test piece before heating are measured; (2) the test piece is placed in a hot air circulating thermostatic chamber, and suspended in a state with a load under time and temperature conditions corresponding to the material of the resin film; (3) after heating, the test piece is cooled to room temperature, and then a length of the test piece after the heat treatment is measured for the same portion as the test piece measured previously before heating; and (4) using the obtained value, a thermal shrinkage rate is obtained according to the following Formula (b): thermal ⁢ shrinkage ⁢ rate ⁢ ( dimensional ⁢ change ⁢ rate ) ⁢ ( % ) = 100 × ( Lo - L ) / Lo Formula ⁢ ( b ) wherein, in Formula (b), Lo denotes a size of the test piece before the heating test, and L denotes a size of the test piece after the heating treatment.