# US 5,702,515 A · Stabilised solutions of polysaccharide

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- Number: US 5,702,515 A
- Document ID: US5702515A
- Status: Granted
- Kind: A
- Application number: 08/809,399
- Filed: 1997-03-21
- Granted: 1997-12-30
- Earliest claimed: 1994-10-20
- Assignees: Courtaulds Fibres (Holdings) Limited
- Inventors: Peter George Urben
- Web page: https://patentgrep.com/patent/US5702515A

## CPC

- C08L 1/02: Cellulose; Modified cellulose
- C08B 1/003: {Preparation of cellulose solutions, i.e. dopes, with different possible solvents, e.g. ionic liquids (solutions used in the manufacture of monocomponent artificial filaments or cellulose or derivatives thereof D01F2/02)}
- D01F 2/00: Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C08B: POLYSACCHARIDES; DERIVATIVES THEREOF (polysaccharides containing less than six saccharide radicals attached to each other by glycosidic linkages C07H; fermentation or enzyme-using processes C12P19/00; sugar industry C13; production of cellulose D21)
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS

## Abstract

The use together of (1) an aromatic compound containing a benzene ring bearing at least two substituents selected from the group consisting of hydroxy groups, primary amino groups and secondary amino groups and (2) a sulphur-containing compound containing an --SH group or an anion or precursor thereof, not being a carbocyclic arenethiol, is effective in stabilising solutions of polysaccharides such as cellulose in tertiary amine N-oxides against thermal degradation. Such solutions are useful for the manufacture of extruded articles such as fibers and films.

## Claims

### Claim 1

A solution of a polysaccharide in a hydrated tertiary amine N-oxide, comprising (1) an aromatic compound containing a benzene ring bearing at least two substituents selected from the group consisting of hydroxy groups, primary amino groups and secondary amino groups and (2) a sulphur-containing compound containing an --SH group or an anion thereof or a precursor of such a compound, provided that the said sulphur-containing compound is not a carbocyclic arenethiol.

### Claim 2 (depends on 1)

A solution according to claim 1, wherein the polysaccharide is cellulose.

### Claim 3 (depends on 1)

A solution according to claim 1, wherein the tertiary amine N-oxide is N-methylmorpholine N-oxide.

### Claim 4 (depends on 1)

A solution according to claim 1, wherein the aromatic compound is a polyphenol bearing three phenolic hydroxyl groups on adjacent carbon atoms.

### Claim 5 (depends on 4)

A solution according to claim 4, wherein the aromatic compound is propyl gallate.

### Claim 6 (depends on 1)

A solution according to claim 1, wherein the concentration of the aromatic compound in the solution is in the range 0.01 to 0.5 percent by weight.

### Claim 7 (depends on 6)

A solution according to claim 6, wherein the concentration of the aromatic compound in the solution is in the range 0.01 to 0.1 percent by weight.

### Claim 8 (depends on 1)

A solution according to claim 1, wherein the concentration of the sulphur-containing compound in the solution is in the range 0.05 to 1.0 percent by weight.

### Claim 9 (depends on 8)

A solution according to claim 8, wherein the concentration of the sulphur-containing compound in the solution is in the range 0.1 to 0.5 percent by weight.

### Claim 10

A process for making a shaped article of a polysaccharide including the steps of:
(a) dissolving the polysaccharide in a hydrated tertiary amine N-oxide to form a solution;
(b) extruding the solution through a die to form a shaped member;
(c) passing the shaped member through at least one water-containing bath, thereby removing the solvent from the shaded member and forming the shaped article; and
(d) drying the shaped article,
characterised by incorporating in the solution (1) an aromatic compound containing a benzene ring bearing at least two substituents selected from the group consisting of hydroxy groups, primary amino groups and secondary amino groups and (2) a sulphur-containing compound containing an --SH group or an anion thereof or a precursor of such a compound, provided that the said sulphur-containing compound is not a carbocyclic arenethiol.

### Claim 11 (depends on 10)

A process according to claim 10, wherein the polysaccharide is cellulose.

### Claim 12 (depends on 10)

A process according to claim 10, wherein the tertiary amine N-oxide is N-methylmorpholine N-oxide.

### Claim 13 (depends on 10)

A process according to claim 10, wherein the aromatic compound is a polyphenol bearing three phenolic hydroxyl groups on adjacent carbon atoms.

### Claim 14 (depends on 13)

A process according to claim 13, wherein the aromatic compound is propyl gallate.

### Claim 15 (depends on 10)

A process according to claim 10, wherein the concentration of the aromatic compound in the solution is in the range 0.01 to 0.5 percent by weight.

### Claim 16 (depends on 15)

A process according to claim 15, wherein the concentration of the aromatic compound in the solution is in the range 0.01 to 0.1 percent by weight.

### Claim 17 (depends on 10)

A process according to claim 10, wherein the concentration of the sulphur-containing compound in the solution is in the range 0.05 to 1.0 percent by weight.

### Claim 18 (depends on 17)

A process according to claim 17, wherein the concentration of the sulphur-containing compound in the solution is in the range 0.1 to 0.5 percent by weight.

### Claim 19 (depends on 10)

A process according to claim 10, wherein the shaped article is a fibre or film.