# US 11,441,855 B2 · Thermal interface materials

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- Number: US 11,441,855 B2
- Document ID: US11441855B2
- Status: Granted
- Kind: B2
- Application number: 17/406,335
- Filed: 2021-08-19
- Published: 2021-12-16
- Granted: 2022-09-13
- Earliest claimed: 2019-07-30
- Assignees: Fastcap Systems Corporation
- Applicants: FastCAP Systems Corporation
- Inventors: Yong Joon Lee; William J. Scimeca; Nicolo Brambilla; Daniel Rich
- Web page: https://patentgrep.com/patent/US11441855B2

## CPC

- F28F 21/065: {the heat-exchange apparatus employing plate-like or laminated conduits}
- H05K 7/20445: {the coupling element being an additional piece, e.g. thermal standoff}
- B29C 43/003: {characterised by the choice of material}
- B29C 43/203: {Making multilayered articles}
- B29C 43/32: Component parts, details or accessories; Auxiliary operations
- B29C 69/001: {a shaping technique combined with cutting, e.g. in parts or slices combined with rearranging and joining the cut parts (for reinforced material B29C70/545; B29C49/4278, B29C51/268 take precedence)}
- B32B 25/08: of synthetic resin
- B32B 27/20: using fillers, pigments, thixotroping agents
- H05K 7/20481: {characterised by the material composition exhibiting specific thermal properties}
- H10W 40/22: characterised by their shape, e.g. having conical or cylindrical projections
- H10W 40/257: {having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh or porous structures (H10W40/254, H10W40/251 take precedence)}
- B29K 2101/12: Thermoplastic materials
- B29K 2507/04: Carbon
- B29K 2995/0013: Conductive
- B29L 2031/18: Heat-exchangers or parts thereof
- B32B 2307/302: Conductive
- Y02E 60/14: Thermal energy storage
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A thermal interface material is disclosed. The material includes: a sheet extending between a first major surface and a second major surface, the sheet including: a base material; and a filler material embedded in the base material. The base material may include anisotropically oriented thermally conductive elements. In some embodiments, the thermally conductive elements are preferentially oriented along a primary direction from the first major surface towards the second major surface to promote thermal conduction though the sheet along the primary direction. In some embodiments, the base material is substantially free of silicone. In some embodiments, the thermal conductivity of the sheet along the primary direction is at least 20 W/mK, 30 W/mK, 40 W/mK, 50 W/mK, 60 W/mK, 70 W/mK, 80 W/mK, 90 W/mK, 100 W/mK, or more.

## Claims

### Claim 1

A thermal interface material comprising:
a sheet extending between a first major surface and a second major surface, the sheet comprising a mixture of:
a base material comprises thermoplastic material and is a self-supporting flexible layer selected for encouraging migration of filler material dispersed therein into a desired orientation; and wherein the filler material is at least fifty percent by weight of the sheet, the filler material dispersed in the base material, the filler material comprising anisotropically oriented thermally conductive elements;
wherein the anisotropically oriented thermally conductive elements are oriented along a primary direction from the first major surface towards the second major surface to promote thermal conduction though the sheet along the primary direction;
wherein the base material is substantially free of silicone;
wherein the sheet comprises a slice separated from a stack of a plurality of layers of base material compressed together; each of the layers is embedded with the filler material, and wherein the filler material in each layer comprises anisotropically oriented thermally conductive elements and the orientation of the slice during separation from the stack is such that the thermally conductive elements are oriented along a primary direction from the first major surface towards the second major surface to promote thermal conduction though the sheet along the primary direction and the sheet comprises a region proximal the first major surface or second major surface of the sheet, said region containing a subset of the anisotropically oriented thermally conductive elements of the filler material that are less anisotropically oriented than the anisotropically oriented thermally conductive elements located more distal to said surface.

### Claim 2 (depends on 1)

The thermal interface material of claim 1, wherein the sheet exhibits self-healing properties.

### Claim 3 (depends on 1)

The thermal interface material of claim 1, wherein the base material comprises at least one of acrylic rubber, acrylic resin, epoxy resin, a thermoplastic fluorocarbon and fluorine resin.

### Claim 4 (depends on 1)

The thermal interface material of claim 1, wherein the base material comprises at least one of: poly (2-ethylhexyl acrylate), 2-ethylhexyl acrylate-acrylic acid copolymer, a polymethacrylic acid or its ester, an acrylic resin, a polyacrylic acid or its ester; silicone resins; fluororesins; polyethylene; polypropylene; ethylene-propylene copolymer; polymethylpentene; polyvinyl chloride; polyvinyl acetate; ethylene-vinyl acetate copolymer; polyvinyl alcohol; polyacetal; polyethylene terephthalate; polyethylene; polystyrene; polyacrylonitrile; -styrene acrylonitrile copolymer; acrylonitrile-butadiene-styrene resin; styrene butadiene block copolymer; hydrogenated product of styrene butadiene block copolymer; styrene-isoprene block copolymer; hydrogenated product of styrene-isoprene block copolymer; polyphenylene ether; modified polyphenylene ether; aliphatic polyamide; and aromatic polyamides; polyamide; polycarbonate; polyphenylene sulfide; polysulfone; polyethersulfone; polyethernitrile; polyetherketones; polyketone; polyurethane; liquid crystal polymer; ionomers; and combinations thereof.

### Claim 5 (depends on 1)

The thermal interface material of claim 1, wherein the base material comprises at least one of: vinylidene fluoride, tetrafluoroethylene-propylene, fluorine-containing polymerizable monomer, an elastomer resulting from fluorine-containing polymerizable monomer; a poly-tetrafluoroethylene, a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, polyvinylidene fluoride, polychlorotrifluoroethylene, ethylene-copolymer, tetrafluoroethylene-copolymer, polyvinylfluoride, tetrafluoroethylene-propylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, acrylic-modified polytetrafluoroethylene, polytetrafluoroethylene modified ester, epoxy-modified silane-modified polytetrafluoroethylene and polytetrafluoroethylene.

### Claim 6 (depends on 1)

The thermal interface material of claim 1, wherein the base material comprises at least one of: natural rubber; acrylate rubber; butadiene rubber; isoprene rubber; nitrile rubber; hydrogenated nitrile rubber; chloroprene rubber; ethylene-propylene rubber; chlorinated polyethylene; chlorosulfonated polyethylene; butyl rubber; halogenated butyl rubber; polyisobutylene rubber; polyacrylic rubber; epoxy resin; a polyimide resin; a bismaleimide resin; benzocyclobutene resin; a phenol resin; unsaturated polyester; a diallyl phthalate resin; a polyimide resin; a polyurethane; a thermosetting polyphenylene ether; and thermosetting polyphenylene ether.

### Claim 7 (depends on 1)

The thermal interface material of claim 1, wherein the base material comprises at least one of: poly(vinyl acetate) (PVA); poly(ethenyl ethanoate) (PVAc); and a soy-oil base material.

### Claim 8 (depends on 1)

The thermal interface material of claim 1, wherein the base material is at least partially dissolved in a solvent when the filler material is dispersed therein.

### Claim 9 (depends on 8)

The thermal interface material of claim 8, wherein the solvent comprises isopropyl alcohol.

### Claim 10 (depends on 1)

The thermal interface material of claim 1, wherein the filler material comprises at least one of: carbon nanotubes, bundles of carbon nanotubes, agglomerates of aligned carbon nanotubes; ceramic flake; nano-horns, nano-onions, carbon black, fullerene, graphene and oxidized graphene.

### Claim 11 (depends on 1)

The thermal interface material of claim 1, wherein the filler material comprises at least one of: metal nano-particles, metal oxide nano-particles, and a thermally conductive polymer.

### Claim 12 (depends on 1)

The thermal interface material of claim 1, wherein the filler material comprises at least one of: graphite, boron nitride, boron nitride flakes, boron nitride nano-scrolls, aluminum nitride, aluminum nitride whiskers, carbon nanotubes, metal particles, metal oxide particles.

### Claim 13 (depends on 1)

The thermal interface material of claim 1, wherein the filler material further comprises a distribution of at least one of microscale particles and flakes, wherein the distribution comprises elements that exhibit at least one dimension in the range of about 0.1 microns up to 200 microns.

### Claim 14 (depends on 1)

The thermal interface material of claim 1, wherein the thermal conductivity is at least 40 W/mK.

### Claim 15 (depends on 1)

The thermal interface material of claim 1, wherein the thermal conductivity is at least 70 W/mK.

### Claim 16 (depends on 1)

The thermal interface material of claim 1, wherein the sheet further comprises at least one other thermally conductive element in thermal communication between and exposed at the first major surface and the second major surface.

### Claim 17 (depends on 16)

The thermal interface material of claim 16, wherein the at least one other thermally conductive element comprises one of a sheet, a strip and a pillar.

### Claim 18 (depends on 16)

The thermal interface material of claim 16, wherein the at least one other thermally conductive element comprises at least one of carbon, graphite and graphene.