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
  • D01F2/24—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives
  • D01F2/28—Monocomponent artificial filaments or the like of cellulose or cellulose derivatives; Manufacture thereof from cellulose derivatives from organic cellulose esters or ethers, e.g. cellulose acetate
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/42—Separation; Purification; Stabilisation; Use of additives
  • C07C51/487—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification

Definitions

• This invention relates to the production of artificial threads, films and the like of secondary cellulose acetate by wet spinning, the term thread being used in a general sense to include threads, fibres, filaments, staple fibresand like filamentary materials.
• ammonium salts such as ammonium chloride, ammonium sulphate and ammonium acetate, sodium chloride, sodium sulphate, sodium acetate and calcium chloride
• the object of the present invention is to provide an improved coagulating medium for wet spinning secondary cellulose acetate.
• the cellulose acetate solution used is an aqueous acetic acid solution containing from about 9 to about 15 per cent by weight of cellulose acetate based on the weight of the solution and the coagulating bath employed contains free acetic acid and potassium acetate in a concentration of from 20 per cent by weight up to saturation point; solutions containing concentrations of the order of 40 per cent by weight of potassium acetate are particularly suitable.
• the coagulating bath preferably contains acetic acid in a concentration within the range of from to 250 grams of acetic acid per litre of bath.
• Cellulose acetate spinning solutions for use in this invention are those in aqueous acetic acid which are obtained by the normal acetylation process after ripening and neutralisation of the acid catalyst have been eiiected so that the steps of precipitating, washing and drying the cellu lose acetate in the form of flake are eliminated.
• the concentration of the solution is within the range of from 9 to 15 per cent by weight based on the weight of the solution. 1
• the solution may be clear or pigmented.
• the spinning solution is preferably heated to a temperature higher'than that of the coagulating bath as described for example in British patent specification No. 341,148; for example the spinning solutioncmay be heated to a temperature of about 40 to centigrade while the coagulating bath may be maintained at a temperature within the range of 15 to 45 centigrade, preferably 25 to 35; centigrade, for example about 30" centigrade.
• the concentration of acetic acid in the bath will increase under static conditions. It is therefore preferred to withdraw part of the bath liquor containing acetic acid at a higher concentration, to recover acetic acid from the withdrawn liquor, and to feed potassium acetate solution, containing acetic acid at a lower concentration to the bath in a continuous process so that spinning conditions are maintained substantially constant.
• the present invention is particularly useful for making staple fibres by the process described and claimed in the specification of our co-pending application Serial No. 122,833, dated October 21, 1949.
• potassium acetate as a coagulant in accordance with the present invention permits the production of cellulose acetate threads having filament deniers as low as 1.5, mean fibre tenacities of at least 1.1 grams per denier, and dry extensibilities of 25 to 35 per cent or even 40 per cent in this respect potassium acetate shows a marked improvement over previously proposed coagulants such as sodium acetate.
• Cellulose acetate threads produced by wet spinning with previously known coagulating baths have also generally shown a marked tendency to stain with certain direct cotton dyestuffs thus restricting their possible use in the textile industry.
• Wet-spun threads obtained using coagulating baths containing potassium acetate in accordance with this invention are not markedly stained by direct cotton dyestuffs and in this respect are similar to the normal dry-spun threads.
• the threads obtained according to the invention also resist acid or wool dyes in a manner similar to dry spun threads.
• Films obtained according to the invention are in general clear and lustrous.
• the threads coagulated in accordance with the invention after washing may be treated if desired with softening agents or lubricating agents; they may also be treated after drying with tinting agents or antistatic agents, for example by an atomised spray.
• Example 1 A cellulose acetate solution in an acetic acidwater mixture was prepared as follows:
• the catalyst was then neutralised by adding and mixing in 132 parts of a 19.8 per cent solution of sodium acetate in 50 per cent aqueous acetic acid and then a further 159 parts of acetic acid and 254 parts of water were added and mixed in.
• the solution obtained was filtered and deaerated under vacuum for 6 hours.
• the solution was heated to approximately 55 4 centrigrade and was extruded by a metering pump at a rate of 17.5 cubic centimetres per minute through a jet having 372 holes each of 0.002 of an inch diameter into an aqueous coagulating bath at 30 centigrade containing 40 per cent of potassium acetate and 50 grams of acetic acid per litre of solution.
• the filaments so formed were taken up on a godet at a speed of 23 metres per minute and were then passed to a second godet rotating at a speed designed to stretch the filaments 18 per cent.
• the filaments were then washed free from acid and salt, collected as a thread, and dried in a current of hot air.
• Example 2 The procedure described in Example 1 was repeated with the only exceptions that:
• Example 3 The cellulose acetate solution was the same as that used in Example 1.
• the cellulose acetate solution heated to 55 centigrade was extruded by a pump at a rate of 200 cubic centimetres per minute through a jet having 3000 holes each of 0.002 of an inch in diameter into an aqueous coagulating bath at 30 centigrade containing approximately 40 per cent of potassium acetate and grams of acetic acid per litre of solution.
• the filaments so produced were withdrawn from the bath as a tow of substantially parallel filaments at a speed of 32 metres per minute and were continuously washed with water till free from acid and salt. The tow was then given a 16 per cent stretch in boiling water and dried.
• Example 4 The cellulose acetate spinning solution was similar to that used in Example 2 with the only exception that the cellulose acetate concentration was reduced to 10.25 per cent. It was heated to 50 centigrade and. extruded by a metering pump at a rate of 116 cubic centimetres per minute through a jet having 2500 holes, each of 0.002 of an inch in diameter, into an aqueous coagulating bath at 30 centigrade containing approximately 40 per cent of potassium acetate and grams per litre of acetic acid. The filaments so produced were withdrawn from the bath as a tow of substantially parallel fibres at a speed of 32.4 metres per minute, continuously washed with water till free from acid and salt, then given an 8 per cent stretch in water at 90 Centigrade and dried.
• Example A cellulose acetate solution in an acetic acidwater mixture was prepared as described in Example 1 and was spun as follows:
• the solution was heated to 30 centigrade and was extruded by a metering pump at a rate of 62 cubic centimetres per minute through a slit jet 1 inches long by 0.0025 of an inch wide into an aqueous coagulating bath at 33 to 35 centrigrade containing 40 per cent of potassium acetate and 120 grams of acetic acid-per litre of solution.
• the long axis: of the slit jet was arranged in the horizontal plane with the film issuing from the jet substantially horizontally.
• the resultant film was withdrawn from the bath after an immersion of 6 feet and passed at a films and the like of secondary cellulose acetate comprising extruding a direct acetylation solution consisting essentially of water, acetic acid, and from 9 to 15 per cent by weight of secondary cellulose acetate based on the weight of the solution, through a jet into an aqueous coagulating bath containing potassium acetate in a concentration of from 20 per cent by Weight up to saturation point as an active coagulating medium and also containing free acetic acid.
• a process for the production of threads, films and the like of secondary cellulose acetate comprising extruding a solution consisting of water, acetic acid, and from 9 to 15 per cent by weight of secondary cellulose acetate based on the weight of the solution, through a jet into an aqueous coagulating bath containing potassium acetate in a concentration of per cent by weight as an active coagulating medium and also containing free acetic acid in a concentration within the range of from to 250 grams of acetic acid per litre.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Artificial Filaments (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=10268015

Family Applications (1)

Country Status (7)

Cited By (6)

Families Citing this family (1)

Citations (2)

Family Cites Families (1)

• 1948
  • 1948-11-24 GB GB30524/48A patent/GB652844A/en not_active Expired
• 1949
  • 1949-10-24 NL NL140499A patent/NL70801C/xx active
  • 1949-11-03 GB GB28163/49A patent/GB679203A/en not_active Expired
  • 1949-11-17 BE BE492232D patent/BE492232A/xx unknown
  • 1949-11-22 DE DEC186A patent/DE937970C/de not_active Expired
  • 1949-11-23 CH CH279590D patent/CH279590A/de unknown
  • 1949-11-24 FR FR1000334D patent/FR1000334A/fr not_active Expired
• 1950
  • 1950-10-25 DE DEC3317A patent/DE939107C/de not_active Expired
  • 1950-10-27 NL NL156883A patent/NL72012C/xx active
  • 1950-10-31 CH CH290225D patent/CH290225A/de unknown
  • 1950-11-02 BE BE499117D patent/BE499117A/xx unknown
  • 1950-11-03 FR FR1028931D patent/FR1028931A/fr not_active Expired
• 1951
  • 1951-05-11 US US225915A patent/US2632686A/en not_active Expired - Lifetime

Patent Citations (2)

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