# US 11,906,252 B2 · Composite cooling film and article including the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,252 B2 - Document ID: US11906252B2 - Status: Granted - Kind: B2 - Application number: 17/609,716 - Filed: 2020-05-27 - Published: 2022-07-14 - Granted: 2024-02-20 - Earliest claimed: 2019-05-31 - Applicants: 3M Innovative Properties Company - Inventors: Timothy J. Hebrink; Michelle M. Mok; Derek J. Dehn; Mary E. Johansen; Lon R. Johnson; Todd G. Pett; Moses M. David; James P. Burke; Vivian W. Jones; Haiyan Zhang - Web page: https://patentgrep.com/patent/US11906252B2 ## CPC - F28F 13/185: {Heat-exchange surfaces provided with microstructures or with porous coatings} - B32B 3/30: characterised by a layer formed with recesses or projections, e.g. {hollows, grooves, protuberances, ribs (apertured layer B32B3/266; layer with cavities or internal voids B32B3/26)} - B32B 5/18: characterised by features of a layer {of} foamed material - B32B 7/12: using interposed adhesives or interposed materials with bonding properties - B32B 27/08: of synthetic resin - B32B 27/304: {comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF} - F24S 21/00: Solar heat collectors not provided for in groups F24S10/00-F24S20/00 - F28F 19/04: of rubber; of plastics material; of varnish - B32B 2250/03: 3 layers - B32B 2255/10: on synthetic resin layer or on natural or synthetic rubber layer - B32B 2255/205: Metallic coating - B32B 2264/0278: Polyester particles - B32B 2266/0235: Vinyl halide, e.g. PVC, PVDC, PVF, PVDF - B32B 2266/104: Micropores, i.e. with average diameter in the range from 0.1 µm to 0.1 mm - B32B 2307/416: Reflective - B32B 2307/712: Weather resistant - B32B 2307/732: Dimensional properties - F25B 2400/12: Inflammable refrigerants - Y02B 10/20: Solar thermal - F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16) - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - F24S: SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS (for producing mechanical power from solar energy F03G6/00) - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A composite cooling film (100) comprises an antisoiling layer (160) secured to a first major surface of a reflective microporous layer (110). The reflective microporous layer (110) comprises a first fluoropolymer and is diffusely reflective of electromagnetic radiation over a majority of wavelengths in the range of 400 to 2500 nanometers. The antisoiling layer (160) has an outwardly facing antisoiling surface (162) opposite the micro-voided polymer film. An article (1100) comprising the composite cooling film (1112) secured to a substrate (1110) is also disclosed. ## Claims ### Claim 1 A composite cooling film comprising an antisoiling layer secured to a first major surface of a reflective microporous layer, wherein the reflective microporous layer comprises a first fluoropolymer and is diffusely reflective of electromagnetic radiation over a majority of wavelengths in the range of 400 to 2500 nanometers, and wherein the antisoiling layer has an outwardly facing antisoiling surface opposite the reflective microporous layer, wherein the outwardly facing antisoiling surface extends along an axis, wherein a plane containing the axis defines a cross section of the layer and intersects the surface to define a line describing the surface in two dimensions, the layer comprising: a series of micro-structures at least partially defined by the line, the line defining a series of alternating micro-peaks and micro-spaces along the axis, wherein each micro-space comprises a maximum absolute slope defining an angle from the axis of at most 30 degrees, wherein each micro-peak comprises a first micro-segment defining a first average slope and a second micro-segment defining a second average slope, and wherein an angle formed between the first and second average slopes is at most 120 degrees; and a plurality of nano-structures at least partially defined by the line, the line defining at least one series of nano-peaks disposed on at least the micro-spaces along the axis, wherein each nano-peak has a height and each corresponding micro-peak has a height of at least 10 times the height of the nano-peak. ### Claim 2 (depends on 1) The composite cooling film of claim 1, further comprising an auxiliary reflective microporous layer secured to the reflective microporous layer opposite the antisoiling layer. ### Claim 3 (depends on 2) The composite cooling film of claim 2, wherein the auxiliary reflective microporous layer comprises at least one of polyethylene, polypropylene, polysaccharides, or polyethylene terephthalate. ### Claim 4 (depends on 1) The composite cooling film of claim 1, wherein the micro-peak first average slope is positive, and the micro-peak second average slope is negative. ### Claim 5 (depends on 1) The composite cooling film of claim 1, wherein an absolute value of the micro-peak first average slope is equal to an absolute value of the micro-peak second average slope. ### Claim 6 (depends on 1) The composite cooling film of claim 1, wherein a boundary between each adjacent micro-peak and micro-space includes at least one of a bend or an inflection point of the line. ### Claim 7 (depends on 1) The composite cooling film of claim 1, wherein a width of each micro-space is at least one of: at least 10% of a corresponding micro-peak distance, or at least 10 micrometers. ### Claim 8 (depends on 1) The composite cooling film of claim 1, wherein a micro-peak distance between micro-peaks is in a range from 1 micrometer to 1000 micrometers. ### Claim 9 (depends on 1) The composite cooling film of claim 1, wherein the micro-peaks have a height of at least 10 micrometers. ### Claim 10 (depends on 1) The composite cooling film of claim 1, wherein each nano-peak comprises a first nano-segment defining a first average slope and a second nano-segment defining a second average slope, wherein an angle formed between the nano-peak first average slope and the nano-peak second average slope is at most 120 degrees. ### Claim 11 (depends on 10) The composite cooling film of claim 10, wherein an absolute value of the nano-peak first average slope is different than an absolute value of the nano-peak second average slope. ### Claim 12 (depends on 1) The composite cooling film of claim 1, wherein the plurality of nano-structures is further disposed on the micro-peaks. ### Claim 13 (depends on 1) The composite cooling film of claim 1, wherein each nano-peak defines a nano-peak distance and the corresponding micro-peaks define a micro-peak distance of at least 10 times the nano-peak distance. ### Claim 14 (depends on 1) The composite cooling film of claim 1, wherein a maximum nano-peak distance between nano-peaks is in a range from 1 nanometer to 1 micrometer. ### Claim 15 (depends on 1) The composite cooling film of claim 1, wherein the nano-peaks comprise at least one masking element. ### Claim 16 (depends on 15) The composite cooling film of claim 15, wherein the masking element has a diameter of at most 1 micrometer. ### Claim 17 (depends on 1) The composite cooling film of claim 1, wherein the micro-peaks are non-uniform in at least one of height or shape. ### Claim 18 (depends on 1) The composite cooling film of claim 1, wherein the composite cooling film has an average absorbance of electromagnetic radiation of at least 0.9 over the wavelength range of 8-13 microns. ### Claim 19 (depends on 1) The composite cooling film of claim 1, wherein the outwardly facing outwardly facing antisoiling surface comprises a nano-structured surface superimposed on a micro-structured surface. ### Claim 20 (depends on 19) The composite cooling film of claim 19, wherein the nano-structures are at least partially formed by an ion-etching process. ### Claim 21 (depends on 1) The composite cooling film of claim 1, wherein the antisoiling layer comprises a second fluoropolymer. ### Claim 22 (depends on 1) The composite cooling film of claim 1, wherein the reflective microporous layer comprises a micro-voided film. ### Claim 23 (depends on 22) The composite cooling film of claim 22, wherein the micro-voided film comprises a copolymer of monomers comprising tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride. ### Claim 24 (depends on 22) The composite cooling film of claim 22, wherein the micro-voided polymer film further comprises white inorganic particles. ### Claim 25 (depends on 22) The composite cooling film of claim 22, wherein the micro-voided polymer film further comprises polymer particles. ### Claim 26 (depends on 25) The composite cooling film of claim 25, wherein the polymer particles comprise an aromatic polyester. ### Claim 27 (depends on 22) The composite cooling film of claim 22, further comprising an infrared-reflective layer secured to a second major surface of the micro-voided polymer film opposite the first major surface, wherein the infrared-reflective layer has an average reflectance of at least 0.5 over the wavelength range of 8 to 13 microns. ### Claim 28 (depends on 1) An article comprising the composite cooling film of claim 1 secured to a substrate, wherein the antisoiling layer is further from the substrate than the reflective microporous layer. ### Claim 29 (depends on 1) A method of passive cooling a substrate, the method comprising: providing the composite cooling film according to claim 1 on a substrate; and reflecting sunlight with the composite cooling film.