# US 11,078,601 B2 · Compositions and methods for gel spinning of polyamides

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,078,601 B2
- Document ID: US11078601B2
- Status: Granted
- Kind: B2
- Application number: 16/490,847
- Filed: 2018-02-13
- Published: 2019-12-19
- Granted: 2021-08-03
- Earliest claimed: 2017-03-09
- Assignees: AdvanSix Resins & Chemicals LLC
- Applicants: AdvanSix Resins & Chemicals LLC
- Inventors: Terry Chern; Nathan Heldenbrand; Yue Hu; John A. Young; David J. Loy; James A. Kweeder
- Web page: https://patentgrep.com/patent/US11078601B2

## CPC

- D01D 5/06: Wet spinning methods {(D01D5/0046 takes precedence)}
- C08G 69/14: Lactams
- C08J 3/096: {Nitrogen containing compounds}
- C08J 3/11: from solid polymers
- D01D 1/02: Preparation of spinning solutions
- D01F 1/02: Addition of substances to the spinning solution or to the melt (addition of substances to viscose D01F2/08)
- D01F 6/60: from polyamides (from polyamino acids or polypeptides D01F6/68)
- D01D 5/04: Dry spinning methods {(D01D5/0038 takes precedence)}
- D01D: MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- 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)
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS

## Abstract

A composition for forming a fiber includes at least one polyamide and caprolactam. The at least one polyamide has a number average molecular weight between 38,000 Da and 100,000 Da. The polyamide is at least partially dissolved in the caprolactam. The caprolactam comprises between 20 wt. % and 90 wt. % of the composition.

## Claims

### Claim 1

A composition for forming a fiber, the composition comprising:
at least one polyamide having a number average molecular weight between 38,000 Da and 88,000 Da, derived from formic acid viscosity (FAV) as determined according to ASTM D789 according to the relationship:
Mn=4791.8×(log(FAV))2.4056 ; and
caprolactam, wherein the polyamide is at least partially dissolved in the caprolactam, the caprolactam comprising between 30 wt. % and 90 wt. % of the composition.

### Claim 2 (depends on 1)

The composition of claim 1, wherein the caprolactam comprises between 50 wt. % and 90 wt. % of the composition.

### Claim 3 (depends on 1)

The composition of claim 1, wherein the polyamide has a number average molecular weight between 41,000 Da and 68,000 Da, derived from formic acid viscosity (FAV) as determined according to ASTM D789.

### Claim 4

A method of producing a fiber, the method comprising:
dissolving at least one polyamide having a number average molecular weight between 38,000 Da and 88,000 Da, derived from formic acid viscosity (FAV) as determined according to ASTM D789 according to the relationship:
Mn=4791.8×(log(FAV))2.4056, into caprolactam to form a spinnable solution; and
spinning the spinnable solution by extruding the spinnable solution through a spinneret to form the fiber, wherein the spinnable solution includes between 30 wt. % and 90 wt. % caprolactam.

### Claim 5 (depends on 4)

The method of claim 4, wherein dissolving the at least one polyamide is performed at a temperature of 150° C. to 270° C.

### Claim 6 (depends on 4)

The method of claim 4, wherein the spinnable solution includes between 50 wt. % and 90 wt. % caprolactam.

### Claim 7 (depends on 4)

The method of claim 4, wherein the polyamide has a number average molecular weight between 41,000 Da and 68,000 Da, derived from formic acid viscosity (FAV) as determined according to ASTM D789.

### Claim 8 (depends on 4)

The method of claim 4, further comprising quenching the spun fibers in a quench bath containing a quenching liquid.

### Claim 9 (depends on 8)

The method of claim 8, wherein an air gap is defined between the spinneret and the quenching liquid in the quench bath, the air gap from 0.25 inches to 11 inches in length.

### Claim 10 (depends on 8)

The method of claim 8, wherein quenching the spun fibers includes:
pulling the fiber through the quenching bath in a first direction; and
flowing the quenching liquid in a second direction, the second direction being opposite to the first direction.

### Claim 11 (depends on 8)

The method of claim 8, wherein the quenching liquid has a dynamic viscosity of between 1,000 centipoise and 26,000 centipoise.

### Claim 12 (depends on 8)

The method of claim 8, wherein the quenching liquid is at a temperature from 50° C. to 150° C.