Densified foam for thermal insulation in electronic devices

• US 10,448,541 B2
• Filed: 11/21/2016
• Issued: 10/15/2019
• Est. Priority Date: 11/19/2015
• Status: Active Grant

• Current Assignee: Boyd Corporation
• Original Assignee: Boyd Corporation
• Inventors: Hartman, Richard M., Macioce, Paul J., Tait, Robert W., Ransford, George A.
• Primary Examiner(s): Rojohn, III, Claire E
• Application Number:
  US15/357,800
• Publication Number:
  US 20170150651A1
• Time in Patent Office: 1,058 Days
• CPC Class Codes: B32B 15/043 of metal B32B15/01 takes precedence
• CPC Class Codes: B32B 15/046 of foam
• CPC Class Codes: B32B 15/08 of synthetic resin
• CPC Class Codes: B32B 15/085 comprising polyolefins
• CPC Class Codes: B32B 15/09 comprising polyesters
• CPC Class Codes: B32B 15/095 comprising polyurethanes
• CPC Class Codes: B32B 15/14 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2250/03 3 layers
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2266/0214 Materials belonging to B32B27/00
• CPC Class Codes: B32B 2266/06 Open cell foam
• CPC Class Codes: B32B 2266/08 Closed cell foam
• CPC Class Codes: B32B 2307/204 Di-electric
• CPC Class Codes: B32B 2307/206 Insulating
• CPC Class Codes: B32B 2307/302 Conductive
• CPC Class Codes: B32B 2307/304 Insulating
• CPC Class Codes: B32B 2307/306 Resistant to heat
• CPC Class Codes: B32B 2307/308 Heat stability dimensional stability B32B2307/734
• CPC Class Codes: B32B 2307/58 Cuttability
• CPC Class Codes: B32B 2307/5825 : Tear resistant
• CPC Class Codes: B32B 2307/706 : Anisotropic
• CPC Class Codes: B32B 2307/708 : Isotropic
• CPC Class Codes: B32B 2307/72 : Density
• CPC Class Codes: B32B 2307/722 : Non-uniform density
• CPC Class Codes: B32B 2307/732 : Dimensional properties
• CPC Class Codes: B32B 2457/10 : Batteries
• CPC Class Codes: B32B 2457/20 : Displays, e.g. liquid crystal displays, plasma displays
• CPC Class Codes: B32B 27/06 : as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a layer of a particular substance B32B9/045; next to a bituminous or tarry layer B32B11/046; next to a water setting substance layer B32B13/12; next to a metal layer B32B15/08; next to a glass layer B32B17/10; next to a layer formed of natural mineral fibres or particles B32B19/045; next to a wood layer B32B21/08; next to a cellulosic plastic layer B32B23/08; next to a natural or synthetic rubber layer B32B25/08
• CPC Class Codes: B32B 27/065 : of foam
• CPC Class Codes: B32B 27/281 : comprising polyimides
• CPC Class Codes: B32B 27/32 : comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/34 : comprising polyamides
• CPC Class Codes: B32B 27/36 : comprising polyesters
• CPC Class Codes: B32B 27/40 : comprising polyurethanes
• CPC Class Codes: B32B 5/02 : characterised by structural features of a fibrous or filamentary layer layer formed of metallic wires B32B15/02; layer formed of natural mineral fibres B32B19/02; layer formed of wood fibres B32B21/02
• CPC Class Codes: B32B 5/18 : characterised by features of a layer of foamed material
• CPC Class Codes: B32B 5/245 : another layer next to it being a foam layer
• CPC Class Codes: B32B 7/12 : using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B32B 7/14 : applied in spaced arrangements, e.g. in stripes
• CPC Class Codes: B32B 9/007 : comprising carbon, e.g. graphite, composite carbon
• CPC Class Codes: B32B 9/041 : of metal
• CPC Class Codes: B32B 9/045 : of synthetic resin
• CPC Class Codes: B32B 9/046 : of foam
• CPC Class Codes: B32B 9/047 : made of fibres or filaments
• CPC Class Codes: F28F 13/003 : by using permeable mass, perforated or porous materials F28F13/18 takes precedence
• CPC Class Codes: F28F 21/02 : of carbon, e.g. graphite
• CPC Class Codes: F28F 21/067 : Details
• CPC Class Codes: F28F 2270/00 : Thermal insulation; Thermal decoupling
• CPC Class Codes: F28F 2275/025 : by using adhesives
• CPC Class Codes: H05K 7/20509 : Multiple-component heat spreaders; Multi-component heat-conducting support plates; Multi-component non-closed heat-conducting structures

Abstract

A heat spreading and insulating material using densified foam is provided that has a heat spreading layer that is adhered to an insulating layer. The material is designed to be used with mobile devices that generate heat adjacent to heat sensitive components. The insulating layer is formed from a compressed layer of polyimide foam to increase its density. The polyimide foam retains a significant amount of insulating properties through the densification process. In some embodiments, an EMI shielding layer is added to improve electrical properties of the device. The heat spreading layer is commonly a graphite material with anisotropic heat properties that preferentially conduct heat in-plane. The material may also include pressure sensitive layers to permanently apply the material to the mobile device.

Claims

1. A heat spreading and insulating material for use with a mobile device having heat generating components and heat sensitive components, said material comprising:

a unitary thermal insulating layer formed from a densified sheet of polyimide open cell foam, said densified sheet having a first density between 25-60 kg/m³, said densified sheet having an outwardly facing surface and an oppositely located inwardly facing surface, said outwardly facing surface being spaced from said inwardly facing surface to define a first thickness;

said unitary thermal insulating layer having further densified areas where said insulating layer is further densified to have a density greater than said first density, said outwardly facing surface is spaced from said inwardly facing surface to define a second thickness in said further densified areas said second thickness being smaller than said first thickness;

a first adhesive layer having a first adhesive surface and an oppositely located second adhesive surface, said inwardly facing surface of said insulating layer adheredly contacting said first adhesive surface, said first adhesive layer conforming to said inwardly facing surface;

a heat spreading layer formed from compressed graphite flakes that conducts heat anisotropically and having an adhesive facing surface and an oppositely located component facing surface, said adhesive facing surface separated from said component facing surface to define a thickness, said adhesive facing surface adheredly contacting said second adhesive surface of said first adhesive layer, said heat spreading layer conforming to said second adhesive surface.

2. The heat spreading and insulating material of claim 1, when said heat spreading layer contacts said heat generating components, heat from said heat generating components preferentially transfers along said thickness of said heat spreading layer.