# US 11,441,001 B1 · Process to manufacture carbon fiber intermediate products in-line with carbon fiber production

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- Number: US 11,441,001 B1
- Document ID: US11441001B1
- Status: Granted
- Kind: B1
- Application number: 16/699,362
- Filed: 2019-11-29
- Granted: 2022-09-13
- Earliest claimed: 2018-11-29
- Assignees: University of Tennessee Research Foundation
- Applicants: University of Tennessee Research Foundation
- Inventors: George Ervin Husman; Uday Kumar Vasant Vaidya
- Web page: https://patentgrep.com/patent/US11441001B1

## CPC

- C08J 5/042: {with carbon fibres}
- B29B 15/105: {of reinforcement of definite length with a matrix in solid form, e.g. powder, fibre or sheet form (calendering B29C70/506)}
- B29B 15/125: {by dipping}
- B29C 35/16: Cooling {(cooling extruded material B29C48/911; cooling preforms for blow moulding B29C49/6427; cooling blown articles B29C49/66; cooling tyres during post cure inflation B29D30/0643)}
- B29C 70/10: characterised by the structure of fibrous reinforcements {, e.g. hollow fibres}
- C08J 5/243: {using carbon fibres}
- B29C 70/50: for producing articles of indefinite length, e.g. prepregs, sheet moulding compounds [SMC] or cross moulding compounds [XMC]
- B29C 2035/1616: {using liquids}
- B29C 2035/1658: {using gas}
- C08J 2300/22: Thermoplastic resins
- C08J 2300/24: Thermosetting resins
- C08J 2323/12: Polypropene
- C08J 2333/24: Homopolymers or copolymers of amides or imides
- C08J 2363/00: Characterised by the use of epoxy resins; Derivatives of epoxy resins
- C08J 2367/00: Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
- C08J 2377/02: Polyamides derived from omega-amino carboxylic acids or from lactams thereof (C08J2377/10 takes precedence)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- 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

A process of preparing carbon fiber reinforced polymer (CFRP) intermediate products is described wherein the carbon fibers are prepared from a carbon fiber precursor and then in-line impregnated with a polymeric resin as part of a continuous process. The process can provide cost savings compared to processes wherein carbon fibers are prepared and then impregnated with polymeric resins in a separate process, thereby making the use of CFRP materials more economically feasible. Also described is a system for preparing carbon fiber from a carbon fiber precursor and impregnating the carbon fiber with polymeric resin to provide CFRP intermediate products, such as continuous tapes or rods or discontinuous flakes or pellets.

## Claims

### Claim 1

A process for preparing a carbon fiber reinforced polymer (CFRP) intermediate product, wherein the CFRP intermediate product comprises carbon fiber and a thermoplastic or a thermosetting polymeric matrix, the method comprising: forming carbon fiber from a carbon fiber precursor and in-line impregnating the carbon fiber with a polymeric resin corresponding to the thermoplastic or thermosetting polymer matrix, wherein forming the carbon fiber from the carbon precursor and impregnating the carbon fiber with a polymeric resin corresponding to the thermoplastic or thermosetting polymeric matrix are performed in a single or integrated production line and at a single line speed, thereby providing a CFRP intermediate product, wherein the carbon fiber precursor is selected from the group consisting of poly(acrylonitrile) (PAN) fiber, rayon fiber, cellulose fiber, and pitch fiber, and the polymeric resin comprises a thermoplastic polymer selected from the group consisting of a polyolefin, a polyamide, a polyimide, and a polyurethane, or a thermosetting polymer selected from the group consisting of an epoxy, a polyimide, and a polyester.

### Claim 2

A process for preparing a carbon fiber reinforced polymer (CFRP) intermediate product, wherein the CFRP intermediate product comprises carbon fiber and a thermoplastic or thermosetting polymeric matrix, the process comprising:
(a) providing a carbon fiber precursor;
(b) treating the carbon fiber precursor to form carbon fiber;
(c) surface treating the carbon fiber, wherein the surface treating comprises at least one of washing, surface oxidizing, and surface etching the carbon fiber;
(d) impregnating the surface treated carbon fiber with a polymeric resin corresponding to the thermoplastic or thermosetting polymeric matrix of the CFRP intermediate product, thereby providing impregnated carbon fiber;
(e) cooling the impregnated carbon fiber to provide a cooled, impregnated carbon fiber, wherein the cooling is performed while maintaining the impregnated carbon fiber in a tape or ribbon geometry, or wherein the cooling is performed while shaping the impregnated carbon fiber into a rod-shaped geometry having a circular or other cross-sectional shape; and
(f) processing the cooled, impregnated carbon fiber to provide the CFRP intermediate product, wherein steps (c)-(f) are performed in a continuous process at a single processing speed.

### Claim 3 (depends on 2)

The process of claim 2, wherein the carbon fiber precursor is selected from the group consisting of poly(acrylonitrile) (PAN) fiber, rayon fiber, cellulose fiber, and pitch fiber.

### Claim 4 (depends on 2)

The process of claim 2, wherein the carbon fiber precursor is poly(acrylonitrile) (PAN) fiber and wherein step (b) comprises:
(b1) oxidizing PAN fiber to provide oxidized and/or stabilized PAN fiber; and
(b2) carbonizing the oxidized and/or stabilized PAN fiber.

### Claim 5 (depends on 2)

The process of claim 2, wherein the carbon fiber comprises one or more carbon fiber tows, wherein each carbon fiber tow comprises between about 3,000 and about 50,000 carbon fiber filaments.

### Claim 6 (depends on 2)

The process of claim 2, further comprising contacting the carbon fiber with one or more sizing agents after step (c) and prior to step (d).

### Claim 7 (depends on 2)

The process of claim 2, further comprising drying the carbon fiber prior to step (d).

### Claim 8 (depends on 2)

The process of claim 2, further comprising heating the carbon fiber to a melt temperature of the polymeric resin corresponding to the thermoplastic or thermosetting polymeric matrix of the CFRP intermediate product prior to step (d).

### Claim 9 (depends on 8)

The process of claim 8, wherein the heating comprises pulling the carbon fiber over a heated, polished bar or through an oven.

### Claim 10 (depends on 2)

The process of claim 2, wherein step (d) comprises pulling the carbon fiber through one or more impregnation dies and injecting or extruding the polymeric resin into the one or more impregnation dies.

### Claim 11 (depends on 10)

The process of claim 10, wherein the carbon fiber comprises at least two carbon fiber tows and wherein each of the at least two carbon fiber tows is pulled through a separate impregnation die.

### Claim 12 (depends on 10)

The process of claim 10, wherein the carbon fiber comprises at least two carbon fiber tows and wherein two or more carbon fiber tows are pulled through the same impregnation die.

### Claim 13 (depends on 10)

The process of claim 10, wherein the one or more impregnation dies are heated to a melt temperature of the polymeric resin.

### Claim 14 (depends on 10)

The process of claim 10, wherein the polymeric resin comprises a thermoplastic polymer selected from the group consisting of a polyolefin, a polyamide, a polyimide, and a polyurethane.

### Claim 15 (depends on 10)

The process of claim 10, wherein the polymeric resin comprises a thermosetting polymer selected from the group consisting of an epoxy, a polyimide, and a polyester.

### Claim 16 (depends on 2)

The process of claim 2, wherein the cooling is performed while maintaining the impregnated carbon fiber in a tape or ribbon geometry.

### Claim 17 (depends on 16)

The process of claim 16, wherein the cooling is performed by pulling the impregnated carbon fiber over and under a series of at least two free turning cylinders.

### Claim 18 (depends on 2)

The process of claim 2, wherein the cooling is performed while shaping the impregnated carbon fiber into a rod-shaped geometry having a circular or other cross-sectional shape.

### Claim 19 (depends on 18)

The process of claim 18, wherein the shaping is performed by pulling the impregnated carbon fiber through a die having an outlet with a circular or other shaped outlet.

### Claim 20 (depends on 2)

The process of claim 2, wherein in step (f), the cooled, impregnated carbon fiber is fed into a chopper or a pelletizer or onto a winder.

### Claim 21 (depends on 2)

The process of claim 2, wherein the CFRP intermediate product comprises between about 10 weight % carbon fiber and about 70 weight % carbon fiber.