# US 12,114,403 B1 · Carbon nanotube heater composite tooling apparatus and method of use

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- Number: US 12,114,403 B1
- Document ID: US12114403B1
- Status: Granted
- Kind: B1
- Application number: 18/539,816
- Filed: 2023-12-14
- Granted: 2024-10-08
- Earliest claimed: 2021-02-05
- Assignees: Mainstream Engineering Corporation
- Applicants: Mainstream Engineering Corporation
- Inventors: Anna P. Skinner; Kayla S. O'Neill; Rachna C. Igwe; Philip Cox; Justin J. Hill
- Web page: https://patentgrep.com/patent/US12114403B1

## CPC

- H05B 3/145: {Carbon only, e.g. carbon black, graphite}
- B29C 33/02: with incorporated heating or cooling means
- B29C 33/3807: {Resin-bonded materials, e.g. inorganic particles}
- H05B 3/34: flexible, e.g. heating nets or webs
- H05B 2203/005: using multiple resistive elements or resistive zones isolated from each other
- H05B 2203/011: Heaters using laterally extending conductive material as connecting means
- H05B 2203/013: Heaters using resistive films or coatings
- H05B 2214/04: Heating means manufactured by using nanotechnology
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- 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)

## Abstract

The present invention is an apparatus for curing composites out-of-autoclave and out-of-oven. The apparatus is a multilayered composite tool for shaping and curing composites. It also contains a sealant layer and composite resistive heating element on the tool's surface. This heating element provides heat to the composites during cure while binding it to the other layers, eliminating the need for external heat from autoclave and oven sources. A ceramic layer is applied to the top surface of the resistive heater for electrical insulation, heater protection and to provide a smooth surface for finish for the composite components being processed with the invention. A method for using the invention is also described. Finally, one embodiment of the invention is presented where a negative composite tool is created to apply additional pressure to the composite component during curing. This additional pressure enables the current invention to more closely mimic autoclave composite processing.

## Claims

### Claim 1

A curing components out of autoclave and out of oven tool, comprising:
a main tool plate made from a material having a thermal conductivity less than 2 W/m-K and is part of said curing components out of autoclave and out of oven tool;
a sealant layer directly applied onto the main tool plate and closes off surface porosity and is part of said curing components out of autoclave and out of oven tool;
a carbon nanotube resistive heater that is a network of electrically connected carbon nanotubes encompassed within a binder material and is directly applied onto the sealant layer and is part of said curing components out of autoclave and out of oven tool;
a plurality electrical conductors made from a thermoset or thermoplastic material in conjunction with a metal conductor and connected to the heater and is part of said curing components out of autoclave and out of oven tool; and
a ceramic topcoat is applied on the heater and the electrical conductors and is part of said curing components out of autoclave and out of oven tool.

### Claim 2 (depends on 1)

The tool of claim 1, wherein the heater comprises a plurality of carbon nanotubes having an areal density between 0.1 to 3 grams per square meter.

### Claim 3 (depends on 2)

The tool of claim 2, wherein the heater comprises a plurality of carbon nanotubes having an areal density between 0.75 to 1 gram per square meter.

### Claim 4 (depends on 2)

The tool of claim 2, wherein the plurality of carbon nanotubes have a diameter between 0.4 to 200 nanometers and a length equal to or greater than 0.1 microns.

### Claim 5 (depends on 3)

The tool of claim 3, wherein the plurality of carbon nanotubes have a diameter between 0.4 to 200 nanometers and a length equal to or greater than 0.1 microns.

### Claim 6 (depends on 1)

The tool of claim 1, further comprising:
a vacuum bag laid directly on top of the ceramic topcoat and containing a composite prepreg fibers that will become cured upon application of heat to the heaters and a vacuum being pulled.