US3809738A - Production of acrylic composite fibers - Google Patents

Production of acrylic composite fibers Download PDF

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Publication number
US3809738A
US3809738A US00312355A US31235572A US3809738A US 3809738 A US3809738 A US 3809738A US 00312355 A US00312355 A US 00312355A US 31235572 A US31235572 A US 31235572A US 3809738 A US3809738 A US 3809738A
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acrylonitrile
heat
filaments
fibers
fiber
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US00312355A
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English (en)
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K Shimoda
Y Kobayashi
T Sumi
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Japan Exlan Co Ltd
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Japan Exlan Co Ltd
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    • 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
    • D—TEXTILES; PAPER
    • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
    • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
    • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
    • D02J1/22—Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch
    • D02J1/229—Relaxing

Definitions

  • This invention relates to an improvement in production of acrylic conjugate fibers having latent three-dimensional coil crimps.
  • conjugate fibers sometimes called composite fibers
  • fiber forming components polymers
  • Their use is based on the development of three-dimensional coil crimps due to the difference in thermal shrinkage of the components constituting the fiber.
  • excess coil crimps are developed in the conjugate fibers, it becomes difiicult to handle them in the subsequent yarn forming step or knitted fabric producing step.
  • 1,027,018 there is suggested a method wherein two or more kinds of polymers different in thermal shrinkage and each consisting mainly of acrylonitrile are compositely extruded through a common orifice to form a composite fiber, which is stretched and collapsed and then restretched under certain temperature conditions.
  • the restretching or tensioning treatment designed to impart latent threedimensional coil crimps to the acrylic conjugate fibers is carried out in a different or separate step from the relaxing step, and therefore it is necessary to provide a special stretching apparatus (e.g. turbostapler or Pacific converter) and hence the process is complicated.
  • a special stretching apparatus e.g. turbostapler or Pacific converter
  • the thus obtained acrylic conjugate fibers have a residual shrinkability, and therefore the dimensional stability of the product, such as yarn or knitted or woven fabric, made from these fiber materials will be impaired.
  • Another object of the present invention is to combine a heat-relaxing treatment step and filament pulling-out step in a process for producing acrylic conjugate fibers so that the process may be shortened and simplified and a desirable latent crimpability imparted to the acrylic conjugate fibers without adopting a restretching step at a temperature above 100 C.
  • a further but different object of the present invention is to find desirable tension and temperature conditions to be applied to acrylic conjugate fibers in the step of pulling them out.
  • FIG. 1 is a stress-strain diagram defining the unreference to the accompanying drawings wherein:
  • FIG. 1 is a stress-strain diagram defiining the uncrimping force of the present invention
  • FIG. 2 is a diagram showing the relation between the acrylonitrile content and uncrimping force in the high shrinking component of an acrylic conjugate fiber
  • FIG. 3 is a diagram showing the relation between the treating temperature to erase the coil crimps of an acrylic conjugate fiber and the uncrimping force
  • FIG. 4 is a vertically sectioned view of an apparatus to be used to carry out the process of the present invention.
  • FIG. 1 illustrates the definition of uncrimping force.
  • a stress-strain diagram of acrylic conjugate fibers having coil crimps the straight line part of the diagram showing that the coil step substantially vanishes, which is the part of the diagram in which Hooks proportional law is considered to hold between the substantial elongation produced in the acrylic conjugate fiber and the tensile stress produced in the crosssection of the fiber.
  • the straight line is extended downward, and an intersection A of said extended line with the curved portion of the line extending from the original point of the stress-strain diagram is determined.
  • the value F (mg./d.) of the tensile stress corresponding to the point A is defined as the uncrimping force.
  • the uncrimping force depends on the acrylonitrile content in the high shrinking component containing from 85 to 94% of acrylonitrile by weight, the temperature at which the filament is pulled out after the heat-relaxing treatment and also on the monofilament denier of the acrylic conjugate fiber.
  • FIG. 2 shows an uncrimping force in hot water at 95 C. of an acrylic conjugate fiber of a monofilament having a fineness of 3 deniers made by preparing a spinning solution in which the acrylonitrile content in the acrylonitrile polymer forming the high shrinking component of the acrylic conjugate fiber is varied within a range of from 85 to 94% by weight and a spinning solution in which the acrylonitrile content in the acrylonitrile polymer forming the low shrinking component is 2% higher than the acrylonitrile content in the high shrinking component, and compositely wet-spinning both spinning solutions to form conjugate fibers, stretching, drying and heat-relaxing treating the fibers.
  • FIG. 3 illustrates the relation between the uncrimping force and the filament heating temperature (represented as a reciprocal number of the absolute temperature in T K.) when pulling a filament (as prepared in the same manner as explained above for FIG. 2) out of the heat-relaxing treatment step.
  • the uncrimping force to be applied to make three-dimensional coil crimps latent and to remove or avoid residual shrinkability will be influenced by the acrylonitrile content in the acrylic polymer forming the high shrinking component of the conjugate fiber and the temperature of pulling out the conjugate filament which has passed through the heat-relaxing step.
  • the objects of the present invention can be attained by pulling out of the heat relaxing step a filament consisting of a high shrinking component having an acrylonitrile content of from 85 to 94% and a low shrinking component in which the acrylonitrile content is higher than in the high shrinking component, while applying thereto tension and temperature conditions represented by in a range of 353T372 or in a range of 333 T353 wherein F is the tension (mg/d.) under which the conjugate fibers are pulled out, AN is the acrylonitrile content (in percent) in the high shrinking component of the conjugate fibers, T is a heating temperature (in K. absolute temperature) at which the filaments are pulled out from the heat-relaxing treatment step and D is the fineness (in denier number) of the monofilament of the conjugate fibers.
  • the spinning solution from acrylonitrile polymers it is necessary to select respective acrylonitrile polymers having different acrylonitrile contents for the high shrinking component and low shrinking component which constitute the conjugate fiber, and to adjust the acrylonitrile content in the component having the low acrylonitrile content, that is, the high shrinking component, to within a range of from 85 to 94%. Further, for the low shrinking component, an acrylonitrile polymer in which the acrylonitrile content is higher than in the high shrinking component is utilized. In case the acrylonitrile content in the high shrinking component exceeds 94%, it will be difficult to impart sufficient coil crimpability to the resulting conjugate fibers.
  • the shrinkage of the fibers in the heat-relaxing treatment step will become so excessive as to remarkably impede various working factors such as the spinnability and uniform dyeability in subsequent steps.
  • the filament heating temperature in the step of pulling out the filaments in order to render three-dimensional coil crimps latent after the heat-relaxing treatment should be in a range of 60 to 99 C. In case the filament heating temperature in this step is below 60 C., the coil crimps developed in the heat-relaxing treatment will not be removed and will not only make it difiicult to process the yarn or knitted or woven fabric in subsequent steps but will also apply an unnecessary frictional force to the filaments in the outlet seal of the heat-relaxing apparatus and frequently damage the fibers.
  • the temperature of the pulling-out step exceeds 99 C.
  • the development of the three-dimensional coil crimps in the subsequent wet-heating or dyeing step of the yarn or knitted or woven fabric will inevitably be insufiicient unless a temperature higher than that used in the pulling-out step is utilized and, as a result, not only will the processing conditions be remarkably restricted but also dimensional stability will be absent and the shape stabilizing property and hand of the product will be impaired.
  • a temperature higher than 99 C. there will be a tendency such that partial elongation is imparted to the filaments with a slight fluctuation of the pulling-out tension and the defect of imparting a partial residual shrinkage to the resulting fiber will result.
  • FIG. 4 illustrates a heat relaxing apparatus having an inlet sealing mechanism 12 and an outlet sealing mechanism 14.
  • Filaments introduced through the inlet sealing mechanism 12 are guided into the main body 50 of a pressure vessel by feeding rolls 16 and 18.
  • the filaments flow down along an inclined chute 22 together with warm water fed through a warm water inlet port 24.
  • the filaments are guided onto a coarse screen conveyer 52 and moved toward the outlet part of the body 50 while being heat-treated in a relaxed state by steam introduced through inlet ports 100.
  • the filaments on the conveyor 52 are subjected to the action of the steam heat having a required temperature While being maintained in a nontensioned state adapted to the desired heat relaxing treatment.
  • the filaments heat-treated in a relaxed state on the conveyer 52 are then passed through a guide rod 53, cage roll 54, guide rod 56 and tension controlling rods 58 adjustably mounted in an outlet water cylinder 66.
  • the filaments are subjected to a pulling-out tension (uncrimping force in the present invention) and are pulled out of the pressure vessel 10 by take-out rolls 82 and 84 through the outlet sealing mechanism 14 so that the three-dimensional coil crimps of the filaments developed on the conveyer 52 are rendered latent.
  • the outlet water cylinder 66 Into the outlet water cylinder 66 is fed hot Water to heat the filaments to the required temperature in pulling out the filaments, the water being fed through a conduit pipe 62 and a reservoir 64 in the vessel. A part of the hot water overflows through an overflowing port 60 of the reservoir so as to constitute a liquid 120 in the vessel 10 and the rest of the hot water is pushed up through the water cylinder 66, passed through the outlet sealing mechanism 14 and an outlet water reservoir 68 and is discharged through a conduit pipe 70.
  • the acrylic composite fibers are stretched, dried and then subjected to the above heat-relaxing treatment.
  • This heat-relaxing treatment is a step indispensable not only to develop and fix the three-dimensional coil crimps but also to improve the fiber properties, particularly the knot strength, and to prevent fibrillation. Without this step, it is impossible to obtain conjugate fibers having practically desirable crirnpability and high strength and elongation. It is desirable to carry out the heat-relaxing treatment at a temperature of 105 to 140 C. while maintaining a moisture content in the filaments of more than 150% (based on the dry fiber weight).
  • the slip between the monofilaments will become insufiicient in that three-dimensional coil crimps will not be adequately developed.
  • the heatrelaxing treatment temperature is below 105 C, there is no sufiicient heat-relaxing effect.
  • the heat-relaxing treatment temperature is above 140 0, threedimensional coil crimps will develop in excess and, even if the pulling-out tension defined by the above formula is applied, it will be difiicult to render the coil crimps latent to the desired extent, and further the whiteness of the resulting fibers will become poor.
  • the spinning operation formation of composite fibers
  • subsequent stretching and drying may be conducted in a well known manner.
  • the composite filaments are dried under a specific temperature and humidity correlated condition so that the fibrillating tendency of the fibers is reduced and the dyeability, wear-resistance and strength of the fibers are improved.
  • acrylonitrile polymers which can be used in the pres ent invention, there can be mentioned acrylonitrile homopolymers and acrylonitrile copolymers containing at least by weight of acrylonitrile and at least one monomer copolymerizable with acrylonitrile as the component other than acrylonitrile.
  • Such homopolymers and copolymers may be obtained by any conventional method.
  • monomer compounds copolymen'zable with acrylonitrile there can be exemplified'methyl acrylate, ethyl acrylate, butyl acrylate, methoxyethyl acrylate, phenyl acrylate, cyclohexyl acrylate, dimethylaminoethyl acrylate and corresponding esters of methacrylic acid; alkyl substituted products and nitrogen substituted products of acrylamides and methacrylamides; unsaturated ketones such as methylvinylketones, phenylvinylketone and methylisopropenylketone; vinyl carboxylates such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate and vinyl benzoate; esters of ethylene alpha-beta-carboxylic acids such as fumaric acid, citraconic acid, mesaconic acid and aconitic acid; N-alkyl-maleinimide; N-vinylcarbazol
  • solvents which can be used to prepare the spinning solutions there can be enumerated concentrated aqueous solutions of a thiocyanate of an alkali metal such as lithium thiocyanate, potassium thiocyanate or sodium thiocyanate or ammonium thiocyanate, concentrated aqueous solutions of an inorganic acid such as sulfuric acid or nitric acid, or organic solvents such as dimethylformamide, dimethylacetamide or dimethylsulfo xide.
  • a thiocyanate of an alkali metal such as lithium thiocyanate, potassium thiocyanate or sodium thiocyanate or ammonium thiocyanate
  • concentrated aqueous solutions of an inorganic acid such as sulfuric acid or nitric acid
  • organic solvents such as dimethylformamide, dimethylacetamide or dimethylsulfo xide.
  • the present invention is not limited to the particular examples.
  • the crimp frequency, crimp product and residual shrinkage referred to in the examples were measured by the below-mentioned methods. Further, except in a special case, the fiber forming component and water content are all represented in terms of percent by weight.
  • Crimp frequency A load of 2 mg. per unit denier was applied to the sample to be measured and the number of crimps per 25 mm. of the length of the sample was measured. This value is defined as the crimp frequency of the fiber to be measured. The test was repeated 20 times and the average value taken.
  • Crimp product The length (a) of a sample under an' initial load (2 mg. per unit denier of the sample to be measured). Then a load of 50 mg. per unit denier was applied to the sample and the length (b) after 50 seconds was measured.
  • the crimp product was determined by the following formula:
  • Crimp product X Residual shrinkage (percent): A load of 300 mg. per unit denier was applied to the sample to be measured and the length (a) of the sample was measured. Then the above-mentioned sample was treated in boiling water for 10 minutes and was dried at 80 C. for 30 minutes. Then a load of 300 mg. per unit denier was applied thereto and the length (b) of the sample was measured. The residual shrinkage was determined by the following formula:
  • the formed composite filaments were washed with water, stretched 9 times the initial length, and then dried in high humidity air having a dry-bulb temperature of 120 C. and wet-bulb temperature of 78 C.
  • the dried composite filaments were continuously fed to the heat-relaxing treatment apparatus shown in FIG. 4 and heat-treated while in a relaxed state in saturated steam at 120 C. for 3 minutes to develop three-dimensional coil crimps.
  • 200% water content was imparted to said filaments by making the filaments flow together with warm water on the inclined chute 22 between the inlet sealing part 12 and the conveyor 52.
  • the filaments heat-treated in a relaxed state were then conveyed continuously to the outlet water cylinder 66 and were pulled out from the heat-relaxing treatment apparatus while maintaining the pulling-out tension according to the present invention by the tension controlling rods 58 provided in said outlet water cylinder 66.
  • the hot water temperature in the outlet water cylinder 66 was varied to be 50, 55, 60, 70, 90 and 99 C.
  • the filaments thus pulled out were dried with hot air at 80 C. to obtain an acrylic conjugate fiber of 3 deniers.
  • the crimp frequency, crimp product and residual shrinkage of the resulting fibers are shown in Table 1.
  • the fibers thus led out were dried with hot air under a temperature condition of 85 C. and then its crimp frequency, crimp product and residual shrinkage were measured.
  • EXAMPLE 3 Filaments spun, stretched and dried in the same manner as in Example 1 were fed to a heat-relaxing treatment apparatus as shown in FIG. 4 and were heat-treated in a relaxed state for 3 minutes in saturated steam at 115- C. to develop three-dimensional coil crimps.
  • the filaments and warm water were made to flow concurrently between the inlet sealing part 12 and the conveyor 52 to impart water to the filaments at such rate as in Table 3.
  • the filaments thus heat-treated in a relaxed state were led to the outlet water cylinder 66 filled with hot water at 70 C. and were pulledout through the outlet seal 14 while a pulling-out tension of 91 mg./ d. was being applied.
  • the coil crimps of the filaments were substantially removed due to the tension of the tension controlling rods 58in the water cylinder 66.
  • EXAMPLE 2 Fibers which were obtained by being spun, stretched, dried and heat-treated in a relaxed state in the same manner as in Example 1 were led into the outlet water cylinder 66 filled with hot water at 70 C. and were pulled out from the heat-relaxing treatment apparatus while the pulling-out tension was being varied by changing the positions of the tension controlling rods 58 provided in said outlet water cylinder 66 to obtain acrylic conjugate fibers of 3 deniers having a latent crimpability.
  • the optimum pulling-out tension to be imparted to the fibers by the tension controlling rods in the outlet water cylinder were treated for 10 minutes in boiling water while being kept unrestricted to develop three-dimensional coil crimps and were then dried with hot air at 70 C.
  • the obtained fiber showed such crimp frequency and crimp product as are shown in Table 3 in response to the variation of the water content given to the filaments in the relaxation heat treatment.
  • Said fibers were then passed through hot water at 75 C., were fed to a stuffing box type crimper, were treated with an oil agent, were then cut with a cutter to form staple fibers, which were then dried with a hot air (85 C.) dryer.
  • the resulting staple fibers had plane zigzag crimps of a crimp frequency of 11.2 and a crimp product of 8.3. Then the fibers were kept unrestricted and treated for minutes in boiling water to develop three-dimensional coil crimps. After they were dried with hot air at 70 C., a crimp frequency of 22 and a crimp product of 32 were recorded.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
  • Multicomponent Fibers (AREA)
  • Artificial Filaments (AREA)
US00312355A 1968-11-26 1972-12-05 Production of acrylic composite fibers Expired - Lifetime US3809738A (en)

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BE (1) BE742167A (xx)
BR (1) BR6914440D0 (xx)
DE (1) DE1959426A1 (xx)
ES (1) ES373892A1 (xx)
GB (1) GB1279269A (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4038452A (en) * 1975-05-07 1977-07-26 Asahi Kasei Kogyo Kabushiki Kaisha Bulky non-woven fabric
BE1016903A3 (nl) * 2006-01-09 2007-09-04 Evilo Nv Werkwijze voor het relaxeren en fixeren van garen en inrichting daarbij toegepast.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4038452A (en) * 1975-05-07 1977-07-26 Asahi Kasei Kogyo Kabushiki Kaisha Bulky non-woven fabric
BE1016903A3 (nl) * 2006-01-09 2007-09-04 Evilo Nv Werkwijze voor het relaxeren en fixeren van garen en inrichting daarbij toegepast.

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DE1959426A1 (de) 1970-06-18
BE742167A (xx) 1970-05-25
BR6914440D0 (pt) 1973-01-16
GB1279269A (en) 1972-06-28
ES373892A1 (es) 1972-02-16

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