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
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/06—Wet spinning methods
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D5/00—Formation of filaments, threads, or the like
  • D01D5/08—Melt spinning methods
  • D01D5/088—Cooling filaments, threads or the like, leaving the spinnerettes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2933—Coated or with bond, impregnation or core
  • Y10T428/2964—Artificial fiber or filament
  • Y10T428/2965—Cellulosic

Definitions

• the invention relates to a method for producing cellulosic molded bodies, wherein a solution of cellulose in a tertiary amine N-oxide and optionally water is formed in a hot state and the molded solution is cooled before introduction into a coagulation bath with air, and a Gam cellulosic filaments.
• the air gap is the area between the shaping element and the coagulation bath in which the cellulose is precipitated.
• the temperature in the air gap is lower than in the spinneret, but is significantly higher than room temperature due to the heat radiation through the spinneret and resulting from the Enthalpiestrom the moldings heating of the air. Due to the permanent evaporation of water, which is usually used as a coagulation bath, so humid conditions are present in the air gap.
• WO 93/19230 to cool the molded solution immediately after molding, faster cooling is effected so that the tackiness of the molded solution decreases correspondingly faster.
• Post-published application WO 98/28218 describes a process for producing cellulose filaments with a solution of cellulose in an organic solvent, wherein the solution is extruded through a die having a plurality of holes to form a plurality of strands, the strands via a gas gap in directs a spin bath containing water to form the filaments and introduces a forced gas flow through the gap parallel to the water surface in the spin bath.
• the air can have a temperature of 0 ° C to 50 ° C.
• the dew point in WO 98/28218 is preferably in the range of 4 to 10 ° C (water vapor content 5 to 7.5 g / kg).
• the temperature of the air is then in the range of 5 ° C to 30 ° C, but the air at 10 ° C may also have a relative humidity of 100%. It is also preferable to use air having a temperature of 10 ° C to 40 ° C and a relative humidity in the dew point range of 4 ° C to 10 ° C, using air having a typical temperature of 20 ° C.
• the object of the present invention is to improve such a method but in particular also the properties of the shaped bodies produced therewith, preferably filaments, or of a filament yarn.
• This object is achieved by a method for producing cellulosic molded bodies, wherein a solution of cellulose in a tertiary amine N-oxide and optionally water is formed in a hot state and the molded solution is cooled before introduction into a coagulation bath with air, wherein the Cooling conditioned air is used, which has a water content of 0.1 to 2 g of water vapor per kg of dry air and their relative humidity is less than 85%.
• This water content of conditioned air corresponds to a dew point range of -8 ° C (2 g of steam per kg of dry air) to about -50 ° C (0.1 g of steam per kg of dry air) and is thus well outside the scope of WO 98/28218 ,
• the water content of the conditioned air is 0.7 (dew point -24 ° C) to 2 g of steam per kg of dry air.
• the cooling can be done with flowing air, which is blown against the formed solution or sucked from this.
• the aspiration may be accomplished by providing conditioned air and soaking it through, for example, a bundle of freshly spun fibers or filaments. Particularly advantageous is a combination of blowing and suction.
• the shaped solution may be exposed to the conditioned air all the way to the coagulation bath, or only over part of that length, it being advantageous to apply the air in the first part, that is, it is advantageous. H. in the region of the air gap, which adjoins directly to the shaping element.
• the conditioned air should flow at an angle of 0 to 120 °, preferably 90 °, relative to the direction of movement of the formed solution, the angle of 0 ° corresponding to an incident flow opposite to the direction of travel of the formed solution.
• fibers in particular filaments, films, hollow fibers, membranes, for example for use in dialysis, oxygenation or filtration can be produced in an advantageous manner.
• the formation of the solution into a desired cellulosic molding can be carried out with known spinnerets for the production of fibers, slot dies or hollow thread spinnerets. Following formation, i. before introducing the shaped solution into the coagulation bath, it can be stretched.
• a yarn of cellulosic filaments prepared from a solution of cellulose in a tertiary amine N-oxide and optionally water, is characterized in that the cross-sectional areas of the filaments have a coefficient of variation of less than 6%.
• the influence of the water content or of the mixing ratio is manifested during filament production, in particular in irregularities of the filament cross sections.
• the coefficient of variation of the filament cross-sectional areas is 30% in a yarn with 50 individual filaments.
• the coefficient of variation at the same temperature lowered to 5.8%.
• Even when using warmer air, for example, 40 ° C. but a low water content of 3.4 g / kg and a relative humidity of 7.4% results in a coefficient of variation of 11.3%, which is thus a factor of 2.7 lower than when using cooler air with higher humidity.
• it is therefore essential to carry out a conditioning of the air gap with dry air.
• the temperature of the cooling air plays rather a minor role.
• the filaments were stretched in the air gap by a factor of 16 and dried after passing through a water bath for coagulation and washed washing baths to remove the NMMO.
• the take-off speed was 420 m / min.
• the respectively obtained filament bundles were cut through at a distance of one meter 2 times perpendicular to the bundle axis.
• the cross-sectional areas of the filaments were transferred by means of a light microscope (magnification 570: 1) and a video camera in a computer-image analysis system (Quantimet 970) and evaluated.
• the area of each filament was determined. From the mean value of the filament cross sections of each bundle examined, where two sectional images were evaluated per bundle, and the standard deviation, the coefficient of variation of the filament cross section area was calculated as the ratio of standard deviation to mean value.
• the resulting air stream was then cooled to the desired temperature with a heat exchanger.
• the relative humidity and the water content were determined with a psychrometer (ALME-MO 2290-2 with psychrometer AN 846 or humidity / temperature probe AFH 9646-2).
• ambient air was cooled until it had a relative humidity of 100%. Subsequently, a further cooling, and the auskondensierende water was deposited. With this procedure, the air was allowed to dry to a water content of about 4 g / kg. Subsequently, the air was reheated to the desired temperature. The relative humidity and water content were measured with the psychrometer.
• the air previously predried by condensation was further dried using a dehumidifier (Model 120 KS from Munters GmbH).
• the reheating of the dry air was also carried out with a heat exchanger.
• the determination of the relative humidity and the water content of the air, which was dried to a water content of less than 4 g / kg, was carried out with a mirror-cooled dew point meter (S4000 RS from MI-CHELL Instruments).
• Table I clearly shows that the lowest coefficients of variation of the filament cross-sectional areas result, almost independently of the temperature of the conditioned air, when the conditioned air has a low water content, as in Examples No. 2. 3. 9. 10 and 11, in which at water contents below 2 g / kg, the coefficient of variation is only of the order of 5 to 6%. The relative humidity in these examples was below 30%.
• Example 22 shows the conditions of the ambient air at a temperature of 21 ° C, at a relative humidity of 60% and a water content of 9.2 g / kg. In this example, although the relative humidity in the claimed area, but not the water content, and there is a coefficient of variation of 23.4%.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Artificial Filaments (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Paper (AREA)

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Publications (3)

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• 1995
  • 1995-11-24 DE DE59502659T patent/DE59502659D1/de not_active Expired - Lifetime
  • 1995-11-24 CN CN95196572A patent/CN1066214C/zh not_active Expired - Lifetime
  • 1995-11-24 PL PL95320507A patent/PL183097B1/pl not_active IP Right Cessation
  • 1995-11-24 WO PCT/EP1995/004634 patent/WO1996017118A1/de active IP Right Grant
  • 1995-11-24 SK SK676-97A patent/SK67697A3/sk unknown
  • 1995-11-24 AU AU41177/96A patent/AU695212B2/en not_active Ceased
  • 1995-11-24 KR KR1019970703672A patent/KR100398294B1/ko not_active IP Right Cessation
  • 1995-11-24 CZ CZ19971674A patent/CZ288742B6/cs not_active IP Right Cessation
  • 1995-11-24 CA CA002205466A patent/CA2205466A1/en not_active Abandoned
  • 1995-11-24 HU HU9702123A patent/HU220367B/hu not_active IP Right Cessation
  • 1995-11-24 EP EP95939293A patent/EP0795052B2/de not_active Expired - Lifetime
  • 1995-11-24 AT AT95939293T patent/ATE167709T1/de not_active IP Right Cessation
  • 1995-11-24 JP JP8518159A patent/JPH10510011A/ja active Pending
  • 1995-11-24 ES ES95939293T patent/ES2120243T5/es not_active Expired - Lifetime
  • 1995-11-24 US US08/849,553 patent/US5902532A/en not_active Expired - Fee Related
• 1996
  • 1996-03-28 TW TW085103928A patent/TW300924B/zh active
• 1998
  • 1998-12-18 US US09/215,216 patent/US6042944A/en not_active Expired - Lifetime

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