Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F2/00—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof
  • D01F2/06—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from viscose
  • D01F2/08—Composition of the spinning solution or the bath

Definitions

• This invention relates to the manufacture of viscose artificial silk and more particularly to a novel method of controlling and regulating the viscosity of viscose spinning solutions.
• the alkali cellulose During the conventional processing steps to convert cellulosic material into spinning solutions of the viscose type, the alkali cellulose must be suitably aged in order to provide a spinning solution having the proper viscosity for practical working operations. If the aging step be omitted, then the viscosity of the viscose solution is too high. It is well known that the degree of aging is dependent on several factors, e. g., aging temperature, aging time and the amount of oxygen coming in contact with the alkali cellulose. If the air containing oxygen is prevented from contacting the alkali cellulose, substantially no aging occurs, or at least, it occurs much more slowly.
• Still another proposal to reduce the viscosity contemplates the contacting of alkali cellulose with a gas that is richer in oxygen content than is the atmosphere. This method also has objections and is far from economical.
• the object of the present invention to provide a method whereby the aging of the alkali cellulose can be entirely eliminated or, at least, theaging period shortened considerably.
• a further object contemplates a relatively simple process that can be practiced without the use of any special chemicals and at normal temperacifically.
• the normal xanthating operation is interrupted after only a portion of the usual quantity of carbon disulphide has been added.
• this definite amount of carbon disulphide has been absorbed by the alkali cellulose crumbs,
• the sulphurizing zone for a short period.
• the remaining quantity of carbon disulphide necessary to fully react with the alkali cellulose is added in the normal way and the resulting cellulose Xanthate is dissolved in dilute alkali to form viscose.
• the decrease in viscosity of the viscose according to this method is much greater than when the same amount of air contacts with entirely undesulphurized alkali cellulose or with normally finished xanthate, the temperature being. maintained the same in all cases.
• the decrease in viscosity of the spinning solution passes through a sharply defined maximum.
• the maximum decrease in viscosity is obtained when the quantity of carbon disulphide added before introducing the air is between 60. and of the total quantity needed.
• the tables set forth below indicate the results of several experiments. These results were obtained when using an alkali cellulose without aging and having a composition comprising 15.5% sodium hydroxide and 29% cellulose and other innocuous constituents.
• the figures which indicate the final viscosity of the viscose are expressed in seconds and are determined by means of a tube-viscosimeter. This viscosimeter consists of a vertical glass-tube of 5.2 mm. internal diameter, open at both ends and which possesses two marks at a distance of 230 mm. The tube is filled with viscose, which is then allowed to flow out under the influence of its own hydrostatic pressure.
• a preparatory treatment for the manufacture of viscose having a normal viscosity from unaged alkali cellulose which comprises forming alkali cellulose and immediately partially sulphurizing the same, suspending the sulphurizing step and introducing air into the alkaline sulphurizing zone and finally completing the sulphurizing action on the alkali cellulose to produce cellulose xanthate.
• a method of converting unaged alkalicellulose into viscose having a normal viscosity which comprises incompletely xanthating alkali cellulose immediately after it has been formed, contacting air containing oxygen with the partially reacted alkaline mass for a limited period, completing the xanthating operation and dissolving the cellulose xanthate in a dilute caustic solution to produce viscose.
• a method according to claim 2 which further provides for the addition of 60 to of the total amount of carbon disulphide needed prior to the introduction of air.
• a method of converting unaged alkali cellulose into viscose having a normal viscosity which comprises partially xanthating alkali cellulose by reacting 25% carbon disulphide, based on the weight of dry cellulose in the alkali cellulose, with alkali cellulose, blowing air containing oxygen in the xanthating zone for at least two hours, completing the xanthating operation by the further addition of 12% carbon disulphide based on the weight of dry cellulose in the alkali cellulose and dissolving the thus formed cellulose xanthate in a dilute caustic solution to produce viscose.
• a method according to claim 2 which further provides for contacting air with the partially reacted mass for a period from three to four hours at a temperature of approximately 25 C.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)
• Artificial Filaments (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=19873725

Family Applications (1)

Country Status (3)

Cited By (5)

• 0
  • NL NL43454D patent/NL43454C/xx active
• 1937
  • 1937-09-30 DE DEN41199D patent/DE719691C/de not_active Expired
  • 1937-10-21 US US170292A patent/US2139302A/en not_active Expired - Lifetime

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