# US 11,993,707 B2 · Polymer composite containing recycled carbon fibers

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- Number: US 11,993,707 B2
- Document ID: US11993707B2
- Status: Granted
- Kind: B2
- Application number: 17/859,367
- Filed: 2022-07-07
- Published: 2022-10-20
- Granted: 2024-05-28
- Earliest claimed: 2018-02-08
- Assignees: Celanese Sales Germany GmbH
- Applicants: Celanese Sales Germany GmbH
- Inventors: Dirk Zierer; Patrick Nickolay; Tim Feuerstack
- Web page: https://patentgrep.com/patent/US11993707B2

## CPC

- C08L 67/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08L67/06 takes precedence)
- C08J 5/042: {with carbon fibres}
- C08K 3/04: Carbon
- C08K 7/06: Elements
- C08J 2367/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence)
- C08J 2467/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08J2467/06 takes precedence)
- C08K 3/346: {Clay}
- C08K 5/103: with polyalcohols
- C08K 5/134: Phenols containing ester groups
- C08K 5/527: Cyclic esters
- C08L 2201/08: Stabilised against heat, light or radiation or oxydation
- C08L 2205/025: containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
- C08L 2205/12: containing additives being liquid crystalline or anisotropic in the melt
- C08L 2205/24: Crystallisation aids
- C08L 2310/00: Masterbatches
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- 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)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

A polymer composition is described well suited for being combined with relatively short fibers. The fibers, for instance, can have a mean fiber length of less than 1,000 microns, such as less than 700 microns, such as less than 500 microns. The polymer formulation allows for intimate mixing with the fibers without having to use a sizing agent. In one embodiment, the composition contains a polybutylene terephthalate polymer combined with a thermoplastic polymer having lower crystallinity.

## Claims

### Claim 1

A reinforced polymer composition comprising:
a polyester polymer comprising a polybutylene terephthalate polymer;
a fatty acid ester blended with the polyester polymer;
a nucleant blended with the polyester polymer;
a heat stabilizing agent and an antioxidant blended with the polyester polymer; and
carbon fibers combined with the polyester polymer, the carbon fibers being present in the polymer composition in an amount from about 5% to about 50% by weight, wherein the carbon fibers are substantially free of a sizing agent, the carbon fibers having a mean fiber length of from about 50 microns to about 500 microns.

### Claim 2 (depends on 1)

A reinforced polymer composition as defined in claim 1, further comprising a second polyester polymer, the second polyester polymer being less crystalline than the polybutylene terephthalate polymer.

### Claim 3 (depends on 2)

A reinforced polymer composition as defined in claim 2, wherein the second polyester polymer has a crystallinity of less than about 40%.

### Claim 4 (depends on 2)

A reinforced polymer composition as defined in claim 2, wherein the second polyester polymer comprises polyethylene terephthalate.

### Claim 5 (depends on 1)

A reinforced polymer composition as defined in claim 1, wherein the fatty acid ester comprises an ester of montanic acid.

### Claim 6 (depends on 1)

A reinforced polymer composition as defined in claim 1, wherein the nucleant comprises talc and wherein the nucleant is present in the composition in an amount from about 0.001% to about 0.5% by weight.

### Claim 7 (depends on 1)

A reinforced polymer composition as defined in claim 1, wherein the heat stabilizer comprises a diphosphite or triphosphite and wherein the antioxidant comprises a sterically hindered phenolic compound.

### Claim 8 (depends on 1)

A reinforced polymer composition as defined in claim 1, wherein the polybutylene terephthalate polymer is present in the composition in an amount from about 20% to about 90% by weight.

### Claim 9 (depends on 1)

A reinforced polymer composition as defined in claim 1, wherein the carbon fibers have a mean fiber length of from about 50 microns to about 200 microns, and wherein the carbon fibers are present in the composition in an amount from about 10% to about 45% by weight.

### Claim 10 (depends on 1)

A reinforced polymer composition as defined in claim 1, wherein the polyester polymer has a crystallinity of greater than about 40%.

### Claim 11 (depends on 1)

A reinforced polymer composition as defined in claim 1, wherein the composition is in a compounded form.