Plastic and nonmetallic article shaping or treating: processes – Forming continuous or indefinite length work – Shaping by extrusion
Patent
1995-06-07
1997-04-22
Tentoni, Leo B.
Plastic and nonmetallic article shaping or treating: processes
Forming continuous or indefinite length work
Shaping by extrusion
10616601, D01D 506, D01F 210
Patent
active
056226667
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to modified viscose fibres and method for their manufacture.
Up to now viscose fibres containing chitosan and chitin/chitosan fibres have been manufactured using a viscose method. Chitin or chitosan is mercerized and reacted with carbon disulfide using a freezing stage at a temperature ranging from -30.degree. to 0.degree. C. The freezing procedure has allowed to produce only chitin or chitosan derivatives able to dissolve in an aqueous sodium hydroxide solution and suitable for application as additives in the manufacture of modified viscose fibres or as a spinning dope for the production of polyaminosaccharide fibres.
The freezing procedure in the case of polyaminosaccharides has been favourable in improving their reactivity with carbon disulfide by a suitable change of the super-molecular structure of chitin/chitosan.
However, the preparation of polyaminosaccharide viscose must be realized in a rather long period, and the use of the freezing procedure in typical industrial conditions has caused several difficulties, which frequently make the production impossible for realization in practice.
Well-known methods for the production of the viscose fibres containing chitosan as well as polyaminosaccharide fibres according to the viscose method are described among others in R. A. A. Muzzarelli's monography "Chitin", Pergamon Press, N.Y., 1977.
The well-known methods of polyaminosaccharide fibres production are based on the spinning of dissolved polymers into a regeneration bath or air.
Japanese Patent 81/112937 describes the production of chitosan fibres and films from an aqueous acid solution of chitosan. The spinning dope is filtered and spun through spinning nozzles and Coagulated in an aqueous solution of anionic surfactants. Alternatively, the dope is sprayed on a smooth surface and then immersed into a coagulation bath to form a film.
Japanese Patent 84/116418 discloses a production of chitosan fibres and films by dissolving chitosan into, a solution of dichloroacetic acid in water. The solution is formed into fibres or films in aqueous solutions of metal salts and the formed product is treated with chelating metals.
Japanese Patent No. 8/106901 describes a method for a chitosan fibres production, based on chitosan and its salts molded from aqueous solutions using a basic gelation bath. Chitosan flakes are dispersed in water and heated with acetic acid at 40.degree. C. to give a dope containing 3% chitosan and 0.5% acetic acid. The dope is spun into a % alleous sodium hydroxide solution at a temperature of
30.degree. C., washed and dried to manufacture 3.5 denier fibres with tenacity of 2.44 G/denier, elongation of 10.8% and knot strengh=of 1.7S G/denier.
European Patent Application EP 77.098 discloses a production of hollow chitosan fibres, useful for ultrafiltration and dialysis, with a diameter of 0.1-1 mm and a thickness of 0.005-0.025 mm. The hollow fibres are produced by spinning the solution into an alkaline coagulant bath through hollow-fiber spinnerets using gaseous ammonia.
Japanese Patent 85/059123 describes the spinning of chitosan fibres by extruding a solution of chitosan in an aqueous acetic acid and urea into a mixture of aqueous base and alcohol. The acetic acid and urea content in the spinning solution are 0.5 to 20 wt % and 0.1 to 10 wt %, respectively. The base bath is usually sodium hydroxide, potassium hydroxide or ammonium hydroxide used in a concentration of 1.0 to 50 wt %.
Japanese Patent 85/40224 describes the manufacture of chitosan fibres with improved tenacity and modulus. The fibres are prepared by spinning the aqueous acid solution of chitosan into air and by subsequently treating with gaseous ammonia and by washing, to obtain fibres with tenacity of 2 G/denier in a dry state, 0.82 G/denier in a wet state, elongation of 11% and modulus of 100 G/denier.
U.S. Pat. No. 4,309,534 also describes a preparation of renatured chitosan fibres and films. The agitation of chitosan in the presence of aqueous solution of acetic acid, glycolic acid and pyruvi
REFERENCES:
patent: 4309534 (1982-01-01), Austin
patent: 4464321 (1984-08-01), Pittalis et al.
Kivekas Olli
Niekraszewicz Antoni
Nousiainen Pertti
Struszczyk Henryk
Novasso Oy
Tentoni Leo B.
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