US2780511A - Methiod of making cellulose acetate teixtile fibers by acetylization of relgenerated cellulose fibers - Google Patents

Methiod of making cellulose acetate teixtile fibers by acetylization of relgenerated cellulose fibers Download PDF

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US2780511A
US2780511A US355150A US35515053A US2780511A US 2780511 A US2780511 A US 2780511A US 355150 A US355150 A US 355150A US 35515053 A US35515053 A US 35515053A US 2780511 A US2780511 A US 2780511A
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fibers
fiber
acetic acid
cellulose
acetylation
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Takagi Takero
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Teijin Ltd
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Toho Rayon Co Ltd
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    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
    • D06M13/10—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing oxygen
    • D06M13/184—Carboxylic acids; Anhydrides, halides or salts thereof
    • D06M13/188—Monocarboxylic acids; Anhydrides, halides or salts thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
    • C08B3/00—Preparation of cellulose esters of organic acids
    • C08B3/06—Cellulose acetate, e.g. mono-acetate, di-acetate or tri-acetate
    • 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
    • D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
    • D01F11/02—Chemical after-treatment of artificial filaments or the like during manufacture of cellulose, cellulose derivatives, or proteins
    • 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

Definitions

  • This invention relates to the preparation of cellulose acetate fiber having an acetic acid content of at least 40% by vapor phase acetylation of cellulosic fibers while retaining the fiber structure.
  • acetaylation of cellulose has hitherto generally been employed commercially to produce only cellulose monoacetate fiber, while fibers having a higher acetic acid content have been made commercially by complete acetylation followed by a dry spinning procedure involving partial hydrolysis to'reduce the acetic acid content.
  • the acetate fiber is a mere modification of ordinary cellulose fiber possessing essentially the same chemical properties and dry afiinity as ordinary cellulose. Dry spun cellulose acetate fiber on the other hand, even when the acetic acid content has been reduced to approximately that of cellulose diacetate, possesses undesirably low tensile strength and high elongation.
  • One object of the present invention is to provide a cellulose acetate fiber having an acetic acid content corresponding approximately to cellulose diacet-ate and celluassignor to Toho Rayon States Patent i trast to the mechanically applied crimp of the thermoplastic fibers, originates in the fine inner structure of the fibers and is permanent through spinning, weaving, washing, ironing and other similar fabric treatments, which makes such viscose fiber particularly valuable.
  • the per manent structural crimp of such viscose staple rayon is retained throughout the acetylation process of the present invention.
  • the invention may be applied to continuous cellulosic fibers which may be lightly twisted together to form a yarn or rope prior to acetylation, or it may be applied to a mass of loose staple fibers which may be conveyed through the several steps of the process on a suitable belt or wire mesh conveyor, or the like.
  • the lcellulosic fibers, either continuous or staple may be loosely woven 1 or knitted to form a fabric which may then be subjected to the acetylation process of the present invention.
  • the invention is characterized in that the cellulosic fiber is impregnated with an acetylation catalyst from an aqueous solution thereof, dried to remove at least a portion of the water content of the impregnated fiber, treated with acetic acid vapor to replace and remove the residual Water content, then acetyl-ated with acetic acid anhydride in vapor form.
  • the entire process is preferably carried out with the cellulosic fiber advancing continuously through each successive step, particularly the steps involvlose triacetate and having a high tensile strength together with low elongation and essentially the same dyeing characteristics as dry-spun acetate fiber.
  • Another object is to provide a cellulose acetate fiber having a permanent structural crimp and having an acetic acid content from 4062% 4055 by weight.
  • Still a further object is to provide a process for continuous vapor phase acetylation of cellulosic fibers while retaining the fibrous structure of the lcellulosic material.
  • a further object is to provide a method for the vapor phase acetylation of celluosic fibers, particularly fibers of regenerated cellulose, while retaining the fiber structure, without discoloration of the fibers.
  • the present invention may be employed for the production of cellulose acetate fibers from a wide variety of cellulose fibers, including cotton, regenerated cellulose and wood-pulpr
  • .theinvention is particularly be apparent from the by weight, preferably from r that is required for the acetylation reaction, it
  • acetylation catalysts which are suitable for use in the present invention are salts, of which there are particularly preferred the acetates such as potassium,
  • the catalysts are preferably applied to the cellulosic fiber from aqueous solution which may suitably contain from about 10-20% by weight of the desired salt.
  • the fiber may be passed through a container filled with the aqueous salt solution or the solution may be sprayed onto the fibers, the impregnation preferably being carried out at room temperature (although elevated temperatures a may be employed if desired) at which temperature a contact time of from about 10 to about 60 minutes is employed to insure satisfactory impregnation of the fiber.
  • the impregnated fiber which contains about 515% by weight of the catalyst, is then passed between squeeze rolls to remove excess Water, or it may be centrifuged if desired, and further dried in hot air. ordinarily has a water content at this point of from 40-75% by weight, usually from 55-65% by weight.
  • acetic anhydride In order to minimize the quantity of acetic anhydride is preferred to replace and remove the residual water content of the impregnated fibers following the aforementioned drying operation by passing the fibers continuously through a The dried fiber closed chamber filled with acetic acid vapor and main- Patented Feb. 5, 1957 tained at a temperature of 100 to 130 C., preferably at a temperature of 105 to 115 C. Removal and replacement of residual water ordinarily is completed in from to 45 minutes, the best results having been obtained in a period of about to minutes.
  • the fiber is advanced into a separate chamber filled with acetic anhydride vapor and maintained at about 100 to 140 C., preferably at about 110 to 130 C.
  • the fiber In order to achieve the desired degree of acetylation the fiber must be maintained in contact with acetic anhydride vapor for a period of at least 3 hours, preferably from 4 to 7 hours, during which time the supply of acetic anhydride vapor to the reaction chamber-is constantly renewed.
  • the acetic 'acid present in the fiber as it is introduced into the acetylation chamber together with the acetic acid formed during acetylation reaction is constantly withdrawn along with the excess acetic anhydride vapor.
  • the anhydride is then recirculated to the acetylation chamber.
  • the acetylated fiber is continuously withdrawn from the acetylation chamber through a restricted opening, washed with water, oiled and dried.
  • the cellulose acetate fiber of the present invention has unexpectedly excellent physical properties as compared with the convential dry-spun acetate fibers, having a dry tensile strength of at least 1.70 gram/denier, a wet tensile strength of at least 1.30 gram/denier, a loop tensile strength of at least 1.25 gram/denier, whilehaving an ultimate elongation no greater than about 25% (dry) and about 22% (Wet).
  • the physical properties of the preferred fibers of the present invention having an acetic acid content of 55% by weight are even better.
  • the dye afiinity of the acetate fibers of this invention is substantially the same as that of dry-spun acetate fiber, the fibers being dyed with celliton color and not with direct dyes, whereas cellulose monacetate fibers made by fibrous acetylation are dyed with direct color and not with celliton color.
  • the acetate fibers of the present invention have a lower moisture regain (not over 7.5%) than cellulose monoacetate fibers.
  • Viscose rayon staple fiber having a permanent structural crimp (6.8 per cm.) is immersed in an aqueous solution containing about 15% sodium acetate for an hour at room temperature.
  • the fiber is then dehydrated in a centrifuge to reduce the water content to approximately 100% of the weight of the fiber, the amount of catalyst contained in the fiber being then about 10% by weight of the fiber.
  • the fiber is then picked and further dried in hot air to approximately 60% water content.
  • the loose fiber is then placed on a wire mesh conveyor belt on which it is carried through a closed chamber maintained at about 110 C. and filled with acetic acid vapor at atmospheric pressure, the time of exposure of the fibers to the acid vapor being approximately 30 minutes.
  • the fiber comes out of the acid chamber through a slit and is then advanced through a slit into a second closed chamber filled with acetic anhydride vapor at atmospheric pressure, the second chamber being maintained at a temperature of about 130 C.
  • the fiber is allowed to remain in the second chamber for about five hours in order to reach the desired degree of acetylation, the acetic anhydride being vaporized from the lower portion of the chamber from a constantly renewed supply.
  • the acetic acid car tied into this chamber on the fibers, together with any acetic acid formed during the acetylation reaction is constantly removed from the chamber along with excess acetic anhydride vapor.
  • Example 11 Spun-dyed viscose staple fiber having a p :rmanent structural crimp is treated as described in Exam le I, except that an aqueous solution of potassium acetat is used in place oi the sodium acetate solution, the am cunt of catalyst contained in the fiber being about 8% b v weight of the fiber.
  • the chamber containing acetic anhy ride is maintained at a ternperature of 120 C. and the tit exposure of the fiber to the acetic anhydride vapors i hours.
  • the resulting product has an acetic acid con of 53%,the acetylated fiber'having the same permane structural crimp as the original viscose staple fibers.
  • the color of the original dyed viscose staple may be black, blue, brown, orange, yellow, navy blue, pink, purple, red, or any other color and the shade of these colors is not changed by the acetylation procedure.
  • Example 111 Example IV Spun-dyedviscose rayon yarn made from fibers having a permanent structural crimp is treated as described in Example Lexcept that 12% amonium oxalate based on the weight of the ,yarn is employedas the catalyst. The resultingcellulose acetateyarn possesses the same color and crimped :fibrous structure as the original viscose rayon yarn and has an acetic acid content of 49%.
  • Example V Fabric woven from spun-dyed viscose rayon staple fiber having a permanent structural crimp is treated as described in Example 1, except that tertiary sodium phosphate is employed as catalyst, the acetylation being carried out at -130 C. for five hours.
  • the resulting cellulose acetate fabric possesses the same color and crimped fibrous structure as the original and has a 50% acetic acid content.
  • Example VII Viscose rayon staple fibers having a permanent structural crimp are treated as described in Example I, except that the acetylation is carried out for four hours at C.
  • the resulting cellulose acetate fiber possesses the same crimped fibrous structure as the original fiber and has a 42% acetic acid content.
  • Crimp elasticity (percent) 69.8... 65.5.
  • the fiber of the present invention diifers in chemical structure and dyeing properties from the monoacetate fiber, being in these respects closely similar to the dry-spun acetate fiber, but possesses remarkably superior physical properties as compared to the dry-spun acetate fiber.
  • the process of the present invention makes it possible to produce cellulose acetate fibers having the same fiber structure as the starting material and having an acetic acid content approximately equal to cellulose diacetate or triacetate (40-62% by weight) without discoloration or staining of the fiber and without embrittlement.
  • the invention also makes possible the production of such cellulose acetate products in a continuous process using a relatively small amount of acetylation catalyst without the necessity for carrying out the acetylation step at reduced pressures.
  • the fibers of this invention may be produced in the form of a loose mass, lap or roving, which, because of the excellent physical properties of the fibers, is admirably adapted for further processing into yarns, threads, and woven or knitted fabrics, or they may be produced in the finished form of yarns, threads, and woven or knitted fabrics directly from corresponding cellulosic yarns, etc. without loss of fibrous structure.
  • cellulose acetate textile fibers which comprises impregnating regenerated cellulose fibers with 5% to by Weight of an acetylation catalyst salt from an aqueous solution thereof, drying said impregnated fibers to remove a portion of the Water from said impregnated fibers, replacing completely the residual water in said fibers with acetic acid by maintaining said fibers in contact with acetic acid vapor at 100-130 C.
  • the method of acetylating viscose rayon staple textile fibers having a permanent structural crimp which comprises impregnating said fibers with an acetylation salt catalyst from an aqueous solution containing about 10% to 20% of said catalyst to provide impregnated fibers containing about 5% to 15% of said catalyst by weight of the fibers, drying said impregnated fibers to reduce the water content thereof to 40% to by weight, passing said fibers continuously through a chamber maintained at 130 C. and filled with acetic acid vapor with said fibers in contact with said acetic acid vapor for 10 to 45 minutes until the residual water in said fibers has been completely replaced with acetic acid, and subsequently passing the fibers continuously through a chamber maintained at -130 C.
  • cellulose acetate fibers having a permanent structural crimp, an acetic acid content from 40% to 62% by weight, a dry tensile strength of at least 1.70 gram/denier, and a wet tensile strength of at least 1.30 gram/ denier.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Textile Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Polymers & Plastics (AREA)
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  • Medicinal Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Organic Chemistry (AREA)
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  • Biochemistry (AREA)
  • Artificial Filaments (AREA)
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Description

T XTILE, FIBERS BY ACETYLIZATION OF i -GENE RATED CELLULOSE FIBERS Taka i, Tokyo, Japan,
Co., Ltd Tokyo, Japan, a corporation of Japan ,1 "-No Diiawing. Application May 14, 1953,
' Serial No. 355,150
F r j 3Claims. c1. 8-121 This invention relates to the preparation of cellulose acetate fiber having an acetic acid content of at least 40% by vapor phase acetylation of cellulosic fibers while retaining the fiber structure.
It has previously been proposed to acetylate cellulosilc fibers while retaining their fiber structure by carrying out the acetylation both in liquid and vapor phase. However, it has hitherto been impossible to produce a cellulose acetate fiber having an acetic acid content from 4062% by weight (which corresponds approximately to cellulose diacetate or triacetate) free from discoloration and brittleness and having at the same time a high tensile strength and low elongation. Direct acetaylation of cellulose has hitherto generally been employed commercially to produce only cellulose monoacetate fiber, while fibers having a higher acetic acid content have been made commercially by complete acetylation followed by a dry spinning procedure involving partial hydrolysis to'reduce the acetic acid content. In the first case, the acetate fiber is a mere modification of ordinary cellulose fiber possessing essentially the same chemical properties and dry afiinity as ordinary cellulose. Dry spun cellulose acetate fiber on the other hand, even when the acetic acid content has been reduced to approximately that of cellulose diacetate, possesses undesirably low tensile strength and high elongation.
One object of the present invention is to provide a cellulose acetate fiber having an acetic acid content corresponding approximately to cellulose diacet-ate and celluassignor to Toho Rayon States Patent i trast to the mechanically applied crimp of the thermoplastic fibers, originates in the fine inner structure of the fibers and is permanent through spinning, weaving, washing, ironing and other similar fabric treatments, which makes such viscose fiber particularly valuable. The per manent structural crimp of such viscose staple rayon is retained throughout the acetylation process of the present invention.
The invention may be applied to continuous cellulosic fibers which may be lightly twisted together to form a yarn or rope prior to acetylation, or it may be applied to a mass of loose staple fibers which may be conveyed through the several steps of the process on a suitable belt or wire mesh conveyor, or the like. If desired, the lcellulosic fibers, either continuous or staple, may be loosely woven 1 or knitted to form a fabric which may then be subjected to the acetylation process of the present invention.
The invention is characterized in that the cellulosic fiber is impregnated with an acetylation catalyst from an aqueous solution thereof, dried to remove at least a portion of the water content of the impregnated fiber, treated with acetic acid vapor to replace and remove the residual Water content, then acetyl-ated with acetic acid anhydride in vapor form. The entire process is preferably carried out with the cellulosic fiber advancing continuously through each successive step, particularly the steps involvlose triacetate and having a high tensile strength together with low elongation and essentially the same dyeing characteristics as dry-spun acetate fiber.
Another object is to provide a cellulose acetate fiber having a permanent structural crimp and having an acetic acid content from 4062% 4055 by weight.
Still a further object is to provide a process for continuous vapor phase acetylation of cellulosic fibers while retaining the fibrous structure of the lcellulosic material.
A further object is to provide a method for the vapor phase acetylation of celluosic fibers, particularly fibers of regenerated cellulose, while retaining the fiber structure, without discoloration of the fibers.
Other and further objects will description which follows.
The present invention may be employed for the production of cellulose acetate fibers from a wide variety of cellulose fibers, including cotton, regenerated cellulose and wood-pulpr However, .theinvention is particularly be apparent from the by weight, preferably from r that is required for the acetylation reaction, it
ing treatment with acetic acid and with acetic anhydride.
Among the acetylation catalysts which are suitable for use in the present invention are salts, of which there are particularly preferred the acetates such as potassium,
, sodium, or lithium acetates; the phosphates, such as see.-
sodium phosphate, tert.-sodium phosphate, the ammonium phosphates, etc.; the chlorides, such as zinc chloride, cupric chloride, aluminum chloride, stannous chloride, stannic chloride, etc.; the sulfates, such as copper sulfate,
1 aluminum sulfate, zinc sulfate, alum, etc.; and the oxalates, such as ammonium oxalate, ammonium acid oxalate, etc.; and mixtures of any two or more of such salts.
The catalysts are preferably applied to the cellulosic fiber from aqueous solution which may suitably contain from about 10-20% by weight of the desired salt. The fiber may be passed through a container filled with the aqueous salt solution or the solution may be sprayed onto the fibers, the impregnation preferably being carried out at room temperature (although elevated temperatures a may be employed if desired) at which temperature a contact time of from about 10 to about 60 minutes is employed to insure satisfactory impregnation of the fiber. The impregnated fiber, which contains about 515% by weight of the catalyst, is then passed between squeeze rolls to remove excess Water, or it may be centrifuged if desired, and further dried in hot air. ordinarily has a water content at this point of from 40-75% by weight, usually from 55-65% by weight.
In order to minimize the quantity of acetic anhydride is preferred to replace and remove the residual water content of the impregnated fibers following the aforementioned drying operation by passing the fibers continuously through a The dried fiber closed chamber filled with acetic acid vapor and main- Patented Feb. 5, 1957 tained at a temperature of 100 to 130 C., preferably at a temperature of 105 to 115 C. Removal and replacement of residual water ordinarily is completed in from to 45 minutes, the best results having been obtained in a period of about to minutes.
Immediately following the exposure to acetic acid vapor the fiber is advanced into a separate chamber filled with acetic anhydride vapor and maintained at about 100 to 140 C., preferably at about 110 to 130 C. In order to achieve the desired degree of acetylation the fiber must be maintained in contact with acetic anhydride vapor for a period of at least 3 hours, preferably from 4 to 7 hours, during which time the supply of acetic anhydride vapor to the reaction chamber-is constantly renewed. The acetic 'acid present in the fiber as it is introduced into the acetylation chamber together with the acetic acid formed during acetylation reaction is constantly withdrawn along with the excess acetic anhydride vapor. The mixture-is condensed and then distilled in a conventional stainless steel plate column to separate the anhydride from the acid. The anhydride is then recirculated to the acetylation chamber.
The acetylated fiber is continuously withdrawn from the acetylation chamber through a restricted opening, washed with water, oiled and dried.
The cellulose acetate fiber of the present invention-has unexpectedly excellent physical properties as compared with the convential dry-spun acetate fibers, having a dry tensile strength of at least 1.70 gram/denier, a wet tensile strength of at least 1.30 gram/denier, a loop tensile strength of at least 1.25 gram/denier, whilehaving an ultimate elongation no greater than about 25% (dry) and about 22% (Wet). The physical properties of the preferred fibers of the present invention having an acetic acid content of 55% by weight are even better. The dye afiinity of the acetate fibers of this invention, on the other hand, is substantially the same as that of dry-spun acetate fiber, the fibers being dyed with celliton color and not with direct dyes, whereas cellulose monacetate fibers made by fibrous acetylation are dyed with direct color and not with celliton color. In addition, the acetate fibers of the present invention have a lower moisture regain (not over 7.5%) than cellulose monoacetate fibers.
The following specific examples are given by way of illustration and are not intended as a limitation upon the scope of the invention.
Example I Viscose rayon staple fiber having a permanent structural crimp (6.8 per cm.) is immersed in an aqueous solution containing about 15% sodium acetate for an hour at room temperature. The fiber is then dehydrated in a centrifuge to reduce the water content to approximately 100% of the weight of the fiber, the amount of catalyst contained in the fiber being then about 10% by weight of the fiber. The fiber is then picked and further dried in hot air to approximately 60% water content. The loose fiber is then placed on a wire mesh conveyor belt on which it is carried through a closed chamber maintained at about 110 C. and filled with acetic acid vapor at atmospheric pressure, the time of exposure of the fibers to the acid vapor being approximately 30 minutes. The fiber comes out of the acid chamber through a slit and is then advanced through a slit into a second closed chamber filled with acetic anhydride vapor at atmospheric pressure, the second chamber being maintained at a temperature of about 130 C. The fiber is allowed to remain in the second chamber for about five hours in order to reach the desired degree of acetylation, the acetic anhydride being vaporized from the lower portion of the chamber from a constantly renewed supply. The acetic acid car tied into this chamber on the fibers, together with any acetic acid formed during the acetylation reaction is constantly removed from the chamber along with excess acetic anhydride vapor. The mixed vapors are then con- Example 11 Spun-dyed viscose staple fiber having a p :rmanent structural crimp is treated as described in Exam le I, except that an aqueous solution of potassium acetat is used in place oi the sodium acetate solution, the am cunt of catalyst contained in the fiber being about 8% b v weight of the fiber. The chamber containing acetic anhy ride is maintained at a ternperature of 120 C. and the tit exposure of the fiber to the acetic anhydride vapors i hours. The resulting product has an acetic acid con of 53%,the acetylated fiber'having the same permane structural crimp as the original viscose staple fibers. The color of the original dyed viscose staple may be black, blue, brown, orange, yellow, navy blue, pink, purple, red, or any other color and the shade of these colors is not changed by the acetylation procedure.
Example 111 Example IV Spun-dyedviscose rayon yarn made from fibers having a permanent structural crimp is treated as described in Example Lexcept that 12% amonium oxalate based on the weight of the ,yarn is employedas the catalyst. The resultingcellulose acetateyarn possesses the same color and crimped :fibrous structure as the original viscose rayon yarn and has an acetic acid content of 49%.
Example V Example VI Fabric woven from spun-dyed viscose rayon staple fiber having a permanent structural crimp is treated as described in Example 1, except that tertiary sodium phosphate is employed as catalyst, the acetylation being carried out at -130 C. for five hours. The resulting cellulose acetate fabric possesses the same color and crimped fibrous structure as the original and has a 50% acetic acid content.
Example VII Viscose rayon staple fibers having a permanent structural crimp are treated as described in Example I, except that the acetylation is carried out for four hours at C. The resulting cellulose acetate fiber possesses the same crimped fibrous structure as the original fiber and has a 42% acetic acid content.
The superiority of the cellulose acetate fiber of the present invention as compared to cellulose monoacetate made by fibrous acetylation or dry-spun acetylated fiber made by complete acetylation followed by partial hydrolysis is shown in the following table:
vapor at 100-140' C. for a period of at least three hours.
2. The method as defined in claim 1 in which said re- Monoacetate fiber Products of the present Dry-spun aceinventlon tats fiber Acetic a id content (percent).- 61 53.
Tensilelgltrength (d1"y),g. 1.80 1.48.
Tensile strength (wet), g./d. 1.38 0.82.
Tensile grztrenglthfloop), gt./d 183% on ati 'm ercen g y p 19.9 22.7.-. 28.0.
Same as dry-spun cellulose Dyed with cel- Dyed with direct color acetate. Dyed with celliliton color and. and not with celliton ton color and not with not; with direct color. direct color. color.
Moistur regain (percent) 9.5 7.5. 5. 6.4.
Numba of crimp per cm 6.8 (permanent 7.4 (mechanical structural crimp). crunp).
Crimp elasticity (percent) 69.8... 65.5.
It is apparent from the foregoing data that the fiber of the present invention diifers in chemical structure and dyeing properties from the monoacetate fiber, being in these respects closely similar to the dry-spun acetate fiber, but possesses remarkably superior physical properties as compared to the dry-spun acetate fiber.
The process of the present invention makes it possible to produce cellulose acetate fibers having the same fiber structure as the starting material and having an acetic acid content approximately equal to cellulose diacetate or triacetate (40-62% by weight) without discoloration or staining of the fiber and without embrittlement. The invention also makes possible the production of such cellulose acetate products in a continuous process using a relatively small amount of acetylation catalyst without the necessity for carrying out the acetylation step at reduced pressures. Moreover, the fibers of this invention may be produced in the form of a loose mass, lap or roving, which, because of the excellent physical properties of the fibers, is admirably adapted for further processing into yarns, threads, and woven or knitted fabrics, or they may be produced in the finished form of yarns, threads, and woven or knitted fabrics directly from corresponding cellulosic yarns, etc. without loss of fibrous structure.
Although I have herein described specific embodiments of my invention, I do not intend to limit myself solely thereto, but to include all of the obvious variations and modifications within the spirit and scope of the appended claims.
I claim:
1. The method of making cellulose acetate textile fibers which comprises impregnating regenerated cellulose fibers with 5% to by Weight of an acetylation catalyst salt from an aqueous solution thereof, drying said impregnated fibers to remove a portion of the Water from said impregnated fibers, replacing completely the residual water in said fibers with acetic acid by maintaining said fibers in contact with acetic acid vapor at 100-130 C. for a period from 10 to 45 minutes and subsequently acetylating said fibers to an acetic acid content from 40% to 62% by weight while retaining their fibrous form by maintaining said fibers in contact with acetic anhydride generated cellulose fibers are in the form of a loose mass of viscose rayon staple fibers having a permanent structural crimp.
3. The method of acetylating viscose rayon staple textile fibers having a permanent structural crimp which comprises impregnating said fibers with an acetylation salt catalyst from an aqueous solution containing about 10% to 20% of said catalyst to provide impregnated fibers containing about 5% to 15% of said catalyst by weight of the fibers, drying said impregnated fibers to reduce the water content thereof to 40% to by weight, passing said fibers continuously through a chamber maintained at 130 C. and filled with acetic acid vapor with said fibers in contact with said acetic acid vapor for 10 to 45 minutes until the residual water in said fibers has been completely replaced with acetic acid, and subsequently passing the fibers continuously through a chamber maintained at -130 C. and filled with acetic anhydride vapor, the period of contact between said fibers and acetic anhydride vapor being three to seven hours, and continuously removing acetic acid vapor and excess acetic anhydride vapor from said lastnamed chamber until there is produced cellulose acetate fibers having a permanent structural crimp, an acetic acid content from 40% to 62% by weight, a dry tensile strength of at least 1.70 gram/denier, and a wet tensile strength of at least 1.30 gram/ denier.
References Cited in the file of this patent UNITED STATES PATENTS 1,823,350 Clark et a1. Sept. 15, 1931 1,861,320 Rheiner May 31, 1932 1,926,498 Rheiner Sept. 12, 1933 2,253,724 New et al Aug. 26, 1941 FOREIGN PATENTS 263,938 Great Britain Jan. 6, 1927 264,937 Great Britain Jan. 31, 1927 755,267 France Sept. 4, 1933 OTHER REFERENCES Matthews Textile Fibers, 5th ed., May 1947, pages 800, 822, 825.
Textile World, September 1949, pages 111-130.

Claims (1)

1. THE METHOD OF MAKING CELLULOSE ACETATE TEXTILE FIBERS WHICH COMPRISES IMPREGNATING REGENERATED CELLULOSE FIBERS WITH 5% TO 15% BY WEIGHT OF AN ACETYLATION CATALYST SALT FROM AN AQUEOUS SOLUTION THEREOF, DRYING SAID IMPREGNATED FIBERS TO REMOVE A PORTION OF THE WATER FROM SAID IMPREGNATED FIBERS, REPLACING COMPLETELY THE RESIDUAL WATER IN SAID FIBERS WITH ACETIC ACID BY MAINTAINING SAID FIBERS IN CONTACT WITH ACETIC ACID VAPOR AT 100* -130* C. FOR A PERIOD FROM 10 TO 45 MINUTES AND SUBSEQUENTLY ACETYLATING SAID FIBERS TO AN ACETIC ACID CONTENT FROM 40% TO 60% BY WEIGHT WHILE RETAINING THEIR FIBROUS FORM BY MAINTAINING SAID FIBERS IN CONTACT WITH ACETIC ANHYDRIDE VAPOR AT 100* -140* C. FOR A PERIOD OF AT LEAST THREE HOURS.
US355150A 1953-05-14 1953-05-14 Methiod of making cellulose acetate teixtile fibers by acetylization of relgenerated cellulose fibers Expired - Lifetime US2780511A (en)

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GB166/54A GB750702A (en) 1954-01-04 1954-01-04 A method of making cellulose acetate fibre

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3204017A (en) * 1962-06-19 1965-08-31 Toho Rayon Kk Process for the manufacture of bulky fibrous wadding materials
US3215490A (en) * 1959-10-02 1965-11-02 Rhodiaceta Process of acetylating a specific kind of regenerated cellulose and recovering ingredients from the used acetylating bath
US3403145A (en) * 1962-07-10 1968-09-24 Rayonier Inc Acetylation of cellulose
US3490862A (en) * 1965-09-20 1970-01-20 Toho Rayon Kk Method for uniform acetylation in the anhydrous gas-phase acetylation reaction of fibers
US3649341A (en) * 1967-11-17 1972-03-14 Neste Oy Method for manufacturing partially acylated regenerated cellulose foil or fiber
US3720661A (en) * 1971-01-05 1973-03-13 Rhodiaceta Process for producing acetylated regenerated cellulose articles
US5427852A (en) * 1993-07-09 1995-06-27 Rhone-Poulenc Rhodia Aktiengesellschaft Filter tow and method for its manufacture as well as tobacco smoke filter element and method for its manufacture
US5525721A (en) * 1993-06-25 1996-06-11 Yamaha Corporation Acetylation method for material containing cellulose, and manufacturing method for modified wood
US5608051A (en) * 1993-10-28 1997-03-04 Bp Chemicals Limited Acetylation of lignocellulosic materials
US20110091736A1 (en) * 2009-06-25 2011-04-21 Eastman Chemical Company Esterified lignocellulosic materials and methods for making them
CN113897709A (en) * 2021-10-29 2022-01-07 上海纳米技术及应用国家工程研究中心有限公司 Regenerated cellulose wet spinning

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DE1081600B (en) * 1957-03-29 1960-05-12 Egon Eloed Dr Ing Process for the acetylation of cellulose hydrate fibers produced in a conventional manner
GB2271570A (en) * 1992-10-15 1994-04-20 David George Rogers Treating lignocellusosic material with acetic anhydride

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GB263938A (en) * 1925-10-06 1927-01-06 Henry Dreyfus Improvements in or relating to the treatment of cellulosic materials and the production of cellulose derivatives
GB264937A (en) * 1925-10-30 1927-01-31 Henry Dreyfus Improvements in or relating to the manufacture of cellulose derivatives
US1823350A (en) * 1927-06-21 1931-09-15 Eastman Kodak Co Process of esterifying cellulosic materials with vapors of lower fatty acids
US1861320A (en) * 1932-05-31 op basel
US1926498A (en) * 1933-09-12 Process foe ihe prepakaiffiow of
FR755267A (en) * 1932-05-11 1933-11-22 Ste Ind Chim Bale etherification of artificial yarns
US2253724A (en) * 1939-01-18 1941-08-26 Int Standard Electric Corp Process for the esterification of cellulose

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FR565654A (en) * 1922-05-24 1924-02-02 Improvements relating to the manufacture of cellulose derivatives
DE706870C (en) * 1930-02-13 1941-06-07 Chemische Ind Ges Process for esterifying cellulose fibers or structures made from cellulose while maintaining their structure
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US1861320A (en) * 1932-05-31 op basel
US1926498A (en) * 1933-09-12 Process foe ihe prepakaiffiow of
GB263938A (en) * 1925-10-06 1927-01-06 Henry Dreyfus Improvements in or relating to the treatment of cellulosic materials and the production of cellulose derivatives
GB264937A (en) * 1925-10-30 1927-01-31 Henry Dreyfus Improvements in or relating to the manufacture of cellulose derivatives
US1823350A (en) * 1927-06-21 1931-09-15 Eastman Kodak Co Process of esterifying cellulosic materials with vapors of lower fatty acids
FR755267A (en) * 1932-05-11 1933-11-22 Ste Ind Chim Bale etherification of artificial yarns
US2253724A (en) * 1939-01-18 1941-08-26 Int Standard Electric Corp Process for the esterification of cellulose

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3215490A (en) * 1959-10-02 1965-11-02 Rhodiaceta Process of acetylating a specific kind of regenerated cellulose and recovering ingredients from the used acetylating bath
US3204017A (en) * 1962-06-19 1965-08-31 Toho Rayon Kk Process for the manufacture of bulky fibrous wadding materials
US3403145A (en) * 1962-07-10 1968-09-24 Rayonier Inc Acetylation of cellulose
US3490862A (en) * 1965-09-20 1970-01-20 Toho Rayon Kk Method for uniform acetylation in the anhydrous gas-phase acetylation reaction of fibers
US3649341A (en) * 1967-11-17 1972-03-14 Neste Oy Method for manufacturing partially acylated regenerated cellulose foil or fiber
US3720661A (en) * 1971-01-05 1973-03-13 Rhodiaceta Process for producing acetylated regenerated cellulose articles
US5525721A (en) * 1993-06-25 1996-06-11 Yamaha Corporation Acetylation method for material containing cellulose, and manufacturing method for modified wood
US5427852A (en) * 1993-07-09 1995-06-27 Rhone-Poulenc Rhodia Aktiengesellschaft Filter tow and method for its manufacture as well as tobacco smoke filter element and method for its manufacture
US5608051A (en) * 1993-10-28 1997-03-04 Bp Chemicals Limited Acetylation of lignocellulosic materials
US20110091736A1 (en) * 2009-06-25 2011-04-21 Eastman Chemical Company Esterified lignocellulosic materials and methods for making them
US8906466B2 (en) * 2009-06-25 2014-12-09 Eastman Chemical Company Esterified lignocellulosic materials and methods for making them
CN113897709A (en) * 2021-10-29 2022-01-07 上海纳米技术及应用国家工程研究中心有限公司 Regenerated cellulose wet spinning

Also Published As

Publication number Publication date
FR1095607A (en) 1955-06-03
DE1054083B (en) 1959-04-02
GB750702A (en) 1956-06-20

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