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
  • D01F8/00—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof
  • D01F8/04—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers
  • D01F8/08—Conjugated, i.e. bi- or multicomponent, artificial filaments or the like; Manufacture thereof from synthetic polymers with at least one polyacrylonitrile as constituent

Definitions

• This invention relates to a method of manufacturing a composite fiber of the acrylonitrile type which possesses an excellent three-dimensional coil crimp which is resistant to heat and is sufiiciently durable.
• the former method involves a mechanical treatment, employing, for instance, a stuffing box which could damage the fiber; in addition to which the crimp so developed is not sufficiently durable, nor it is resistant to heat.
• the latter method since at least two dissimilar polymers areemployed, the components of the resulting fiber might become separated, resulting in a serious breakdown of the fiber, or uneven dyeing may result owing to the presence of dissimilar compositions of said polymers constituting the fiber.
• the present invention provides means for producing a composite fiber possessing an excellent crimp comparable to that of the conventional composite fiber and yet free from the above-mentioned disadavntages, said means comprising the employment of two or more spinning solutions which differ from each other in polymer concentration but are prepared from the same type of polymer.
• the present invention gives effective crimps, due to specific processing of fibers made from dopes having different concentrates of the same polymer.
• a water-soaked swollen fiber, in gel state, is obtained when a spinning dope of a polymer composed predominantly of acrylonitrile as defined herein below, is coagulated in an aqueous bath. It remains swollen even after passing through washing and hot-stretching steps, but since the degree of swelling primarily depends on the concentration of the polymer in the spinning solutions extruded, a coil crimp is obtained due to the difference in swelling of the components if a composite fiber made up of two or more solutions of a single polymer which have different degrees of swelling potential is dried under 3,463,846 Patented Aug. 26, 1969 "ice no tension.
• the present invention is based on this novel finding.
• the degree of swelling of gel fiber extruded through a spinnerette not only depends on the polymer concentration of spinning solutions but it also is affected by the composition and temperature of the coagulating bath and the washing water, the temperature at which the fiber is stretched, as well as the temperature in other steps where the fiber is heated. It is, therefore, rather easy to change the degree of swelling of fiber in the spinning process, but it is not easy to create certain local differences in swelling in each of the gel fibers processed uniformly. In order to secure a sufiicient crimping effect, which is of any practical importance, according to this invention, it
• the difference in the polymer concen- ,tration of the two or more different spinning solutions of the same polymer be greater than 2 percent.
• the composite fiber which has had its coil-crimping potential fully achieved in the drying or compacting process is then treated with steam whereby said threedimensional crimp is set and, at the same time, the fiber is relaxed.
• the composite fiber of this invention is intrinsically made up of a single type of poly crimps in the course of said heat treatment in relaxedv state, it is necessary to provide a mechanical device whereby not only may the filaments be held under no tension but coil crimps developed already may hold their shapes by restraint due to friction and other physi-. 7
• cal forces This may be achieved by allowing the fiber which has had its coil crimp developed in the course of said drying or compacting process to drop in folds in the bottom of a container made up preferably of wire netting or perforated plate-s, as for instance, in such a manner that the fiber is arranged in many parallel lengths, and, then, the container is closed with a cover which is also made up of wire netting or perforated plates.
• the fiber is arranged in the container at a density of from about 0.2 g./cm. to 0.005 g./cm.
• the container is then tilted by degrees so that the parallel lengths of fiber are also parallel with the direction of gravity, in which state the tension forces acting on the monofilaments are minimized.
• the fiber in this-relaxed state, is heat-treated in steam, whereby the three-dimensional coil crimp is perpetuated and, at the same time, the effect of relaxation heat-treatment is obtained-To attain this dual purpose, the steam treatment must be carried out at temperatures of at least 110 C.
• The'crimp of the composite fiber of this invention which emerges from such a crimp-setting and relaxation heat-treatment is extremely resistant to heat and if this composite fiber is drawn until its coil crimp disappears and, then, is immersed in hot water, the coil crimp is immediately regained. It is obvious that the composite fiberofthis invention has a three-dimensional coil crimp which is superior to the conventional mechanical crimp in both bulkiness and feeling.
• the composite fiber of this invention is intrinsically made up of a single type of polymer, there is encountered neither uneven dyeing nor splitting of the components, the characteristic phenomena of the composite fiber consisting of dissimilar polymers.
• polymers of the acrylonitrile type as used throughout this specification means the polymers composed mainly of acrylonitrile, inclusive of the copolymers between acrylontrile and other vinyl monomers copolymerizable therewith, as well as the mixed polymers with other polymers.
• the other vinyl monomers and other compounds copolymerizable with acrylonitrile include, for example, vinyl acetate, vinyl chloride, vinylidene chloride, acrylic acid, methacrylic acid, and other acrylic acid derivatives, acrylamide N-methylolacrylamide and its related derivatives, vinyl pyridine and its derivatives, allylsulfonic acid, methallylsulfonic acid and its derivatives, as well as all other monomers copolymerizable with acrylonitrile.
• the method of this invention is particularly useful when applied to cases in which a polymer of the acrylonitrile type is dissolved in a solvent such as aqueous solu tions of sodium thiocyanate, nitric acid, zinc chloride, dimethylformamide, or dimethylsulfoxide, and the resulting spinning solution is wet-spun using an aqueous coagulating bath.
• a solvent such as aqueous solu tions of sodium thiocyanate, nitric acid, zinc chloride, dimethylformamide, or dimethylsulfoxide
• the spinnerette used in this example has 6532 orifices, each measuring 0.09 mm. in diameter. Tows of this fiber are then dried in hot air streams at 40 C., 60 C., 80 C., 100 C., and 120 C., respectively, under no tension for 60 minutes.
• a method of manufacturing a helically crimped composite fiber of the acrylonitrile type characterized by the steps of concurrently extruding two or more spinning solutions of the same polymer but having different concentrations of said polymer therein to form a bicomponent fiber, washing and stretching the resulting gel fiber, then drying the same under relaxed conditions at temperatures below 80 C. to develop coil crimps in the fiber, folding the thus-formed crimped fiber in a container so that the resulting folds of fibers lie in layers in a horizontal plane in a relaxed and confined state and at a density of from about 0.2 gm./cm. to 0.005 gnr/cm. and turning the container at an angle of 90 so that the fibers lie in a longitudinal plane and are parallel to each other, and then steaming the folds of fibers at a temperature of at least C.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Multicomponent Fibers (AREA)

Applications Claiming Priority (1)

Publications (1)

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Cited By (5)

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Citations (12)

• 1966
  • 1966-09-07 US US577623A patent/US3463846A/en not_active Expired - Lifetime
  • 1966-09-22 GB GB42418/66A patent/GB1109729A/en not_active Expired
  • 1966-09-23 NL NL6613488A patent/NL6613488A/xx unknown
  • 1966-09-23 ES ES0331522A patent/ES331522A1/es not_active Expired

Patent Citations (12)

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