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
  • D01D5/08—Melt spinning methods
  • D01D5/088—Cooling filaments, threads or the like, leaving the spinnerettes
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2505/00—Industrial
  • D10B2505/02—Reinforcing materials; Prepregs
  • D10B2505/022—Reinforcing materials; Prepregs for tyres
• • 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

Definitions

• the present invention relates to a cellulose fiber having a highly homogeneous section, particularly to a cellulose fiber with lower Coefficient of Variation of section diameter (CV(%)). Specifically, the present invention relates to a cellulose fiber wherein Coefficient of Variation of section diameter (CV(%)) of a mono-filament constituting a multi-filament prepared by dissolving a cellulose powder in liquid N-methylmorpholine N-oxide(hereinafter referred to "NMMO”) is below 2.5.
• NMMO N-methylmorpholine N-oxide
• a lyocell fiber is made from a spinning solution wherein cellulose is dissolved in NMMO and it has an advantage of having high hygroscopicity, dry and wet strength and modulus. Moreover, unlike viscose rayon, lyocell is recognized as an environmentally-friendly fiber which does not pollute the environment with harmful substances. Such a lyocell fiber, as an alternative of rayon, may be used as a tire-cord and for this purpose, the homogeneity of a section diameter of a mono-filament constituting a multi-filament is necessary to accomplish high strength as a tire-cord material. The homogeneity may be expressed as Coefficient of Variation of section diameter (CV(%)).
• WO 2001/86043 discloses lyocell fibers having 6.5% or more in Coefficient of Variation of section diameter (CV(%)).
• the invention disclosed in WO 2001/86043 has an object of increasing Coefficient of Variation of section diameter (CV(%)) and it is not suitable for using as industrial materials, particularly, for tire-cord because it has 6.16 cN/tex to 44 cN/tex (0.7 to 5.0 g/d) in strength as shown in examples.
• US Patent No. 6,773,648 discloses a lyocell fiber having 6 to 17 % in Coefficient of Variation of section diameter (CV(%)) along fiber and 10 to 22 % in Coefficient of Variation of section diameter (CV(%)) between fibers.
• the present invention suggests a method for improving Coefficient of Variation of section diameter by adjusting the temperatures of an air gap and a coagulation bath during the process in order that Coefficient of Variation of section diameter (CV(%)) of a mono-filament constituting a multi-filament is lowered below 2.5.
• the lyocell fiber according to the present invention may have suitable properties for using as a dip cord for tire cord.
• the Coefficient of Variation of section diameter (CV(%)) may be controlled in the desired range by adjusting coagulation coefficient.
• the present invention has an advantage of producing a lyocell multi-filament for using as a dip cord for tire-cord.
• a lyocell fiber having different properties according to each condition of process may be produced.
• the spinning pressure in a spinning nozzle, the diameter and the number of orifice, the spinning speed, the temperature and the air velocity of cooling air in an air gap, and the temperature, the concentration of a coagulation bath are the main factors which determine the properties of a lyocell fiber.
• the lyocell fiber produced according to the present invention is prepared by controlling conditions of process and thereby having suitable properties for tire-cord.
• the properties of the lyocell fiber produced according to the preset invention are influenced not by the above-described factors or others independently, but by the correlation between the factors.
• the present invention is characterized in that such factors are controlled to have the correlation.
• the factors which determine the homogeneity of the produced lyocell fiber may be divided into a cooling condition in an air gap and a coagulating condition. Therefore, the condition factors may be expressed as a coagulation coefficient as a result of a mathematical function of the temperature of the cooling air in the air gap and the temperature of the coagulation bath, as shown below.
• T D means the temperature of a spinning solution
• T A means the temperature of cooling air applied in an air gap
• T c means the temperature of a coagulation bath.
• the coagulation coefficient is adjusted to 0.8 to 1.
• the spinning solution is cooled and the temperature of the spinning solution and the temperature of the coagulation bath are adjusted within a similar temperature range, and then the NMMO contained in the spinning solution is fed into the coagulation bath and spreads slowly therein. In doing so, the homogeneity of a mono-filament may be improved by the lower spreading rate.
• coagulation coefficient is adjusted in the range of 0.8 to 1.
• a softwood pulp having 800 to 1200 in degree of polymerization and 93% or more in the contents of ⁇ -cellulose is pulverized with a crusher into powder with 500 ⁇ m in average diameter.
• An NMMO solution having 10 to 20 wt% in the contents of water is prepared.
• the pulp powder and the NMMO solution are fed into an extruder at the same time.
• the cellulose powder is evenly dispersed, swollen and dissolved in the NMMO solution within the extruder maintained at the temperature of 100 to 110 °C , and then transferred to the spinning nozzle through the spinning line at the temperature of 100 to 110 °C and thereby the spinning solution is prepared.
• the spinning solution is spun through the spinning nozzle into a filament yarn.
• the diameter of the spinning nozzle may be 80 to 130 mm.
• the number of orifice and the ratio of the length to the diameter (L/D ratio) of orifice may be determined.
• the number of orifice may be 800 to 1200
• the diameter of the orifice may be 800 to 2000 ⁇ m
• the L/D ratio of the orifice may be 2 to 5.
• the spinning solution is extruded-spun into an air gap.
• the spinning solution is cooled and solidified in order to draw the spinning solution in the air gap, wherein the air is blown at lower temperature in the range of 5 to 15 °C.
• the solution after being cooled and solidified in the air gap is coagulated into a filament yarn in a coagulating solution at a certain concentration and temperature.
• the lyocell fiber according to the present invention is controlled to have a pre-determined coagulation coefficient in the process of coagulating and thereby the lyocell fiber may have desired properties.
• condition factors may be expressed as a coagulation coefficient as a result of a mathematical function of the temperature of cooling air and the temperature of a coagulation bath, as shown below.
• T D means the temperature of a spinning solution
• T A means the temperature of cooling air applied in an air gap
• T C means the temperature of a coagulation bath.
• the coagulation coefficient may be 0.8 to 1.
• the concentration of the coagulation bath is adjusted in order that the concentration of NMMO is adjusted in the range of 5 to 20 wt%.
• the temperature of the spinning solution and that of the coagulation bath become almost similar and the spreading rate of the NMMO contained in the spinning solution into the coagulation bath goes down as low as it can be.
• the homogeneous coagulation may be accomplished. Therefore, the section of a mono-filament constituting the multi-filament becomes very homogeneous and high strength is accomplished.
• a greige cord is prepared and then a dip cord is prepared.
• the greige cord is prepared by twisting a certain number of ply twist yarn and cable twist yarn to two ply of lyocell fibers. Preferably, the twisting may be carried out at 300/300 TPM to 500/500 TPM for cable twist/ply twist and the number of ply twist yarn and cable twist yarn is not necessarily the same.
• the greige cord by twisting ply twist yarn and cable twist yarn is then dipped to a dipping solution.
• a dip cord for tire is prepared after a resin layer is attached to the greige cord.
• the lyocell fiber for tire-cord according to the present invention has 888.9 to 3666.7 dtex (800 to 3300 in denier) of the entire fineness and 0.56 to 2.22 dtex (0.5 to 2.0 in denier) of each monofilament fineness.
• the lyocell fiber produced by adjusting 0.8 to 1 in coagulation coefficient according to the present invention is characterized with following physical properties:
• the physical properties of the lyocell multi-filament are evaluated as following.
• Samples were subjected a fatigue test using a Goodrich disc fatigue tester which is conventionally used for the fatigue test of tire cords. Then, they were measured for residual strength, and fatigue resistances were compared.
• the fatigue test was conducted under the following conditions: 120 °C , 2500 rpm, and 10 % and 18 % compression. After the fatigue test, the samples were dipped in tetrachloroethylene solution for 24 hours to swell rubber, and then, a cord was separated from the rubber and measured for residual strength. This residual strength was measured using a conventional tensile strength tester by the above-described measurement method (a), after drying at 107 °C for 2 hours.
• a cellulose solution with 11.5 wt% in concentration was prepared by using a mixture of pulp powder with 1200 in degree of polymerization (containing 97% in contents of ⁇ -cellulose), NMMO. 1H 2 O and 0.01 wt% propyl gallate.
• a spinning nozzle that is 100 mm in diameter and has 1000 orifices with 150 ⁇ m in diameter was used to extrude the cellulose solution. In this case, the ratio of length to diameter (L/D) of each orifice was 4 in the spinning nozzle.
• the solution extruded from the spinning nozzle(head temperature at 100 °C ) was exposed to a cooling air at 5 °C and 5 m/sec with 50 mm air gap and then the solution is spun wherein the amount of the extruded solution and the spinning speed were adjusted in order that the final filament fineness is 1111.11 dtex (1000 denier).
• the temperature of coagulating solution was 15 °C in order that the coagulation coefficient is 1.
• the concentration of a coagulation bath was adjusted to 80% in water and 20% in NMMO, and then water-washed, dried and wound in order to obtain a filament yarn. Physical properties of the obtained filament are described in Table 1.
• a lyocell multi-filament was prepared by the same process as example 1, only except for changing the temperature of the cooling air in the air gap to 10 °C (for example 2) and 15 °C (for example 3), and the temperature of the coagulation bath to 20 °C ( for example 2) and 25 °C (for example 3) in order that the coagulation coefficient is 1. Physical properties of the obtained filament are described in Table 1.
• a lyocell multi-filament was prepared by the same process as example 1, only except for changing the amount of the extruded solution and the spinning speed in order that the final filament fineness is 1666.66 dtex (1500 denier). In this case, the temperature of the coagulating solution is adjusted in order that the coagulation coefficient is 1. Physical properties of the obtained filament are described in Table 1. Table 1 fineness T D T A ' T D' T C coagulation coefficient Tenacity breaking elongation (%) CV(%) Ex.1 1111.11dtex (1000d) 100 5 15 15 1 64.24 cN/tex (7.3g/d) 6.8 0.7 Ex.2 1111.11dtex (1000d) 100 10 20 20 1 68.
• a lyocell multi-filament was prepared by the same process as example 1, only except for changing the temperature of the coagulation bath to 20 °C (for comp. ex. 1) and 15 °C (for comp. ex. 2) in order that the coagulation coefficient is 0.75 (for comp. ex. 1) and 1.33 (for comp. ex. 2). Physical properties of the obtained filament are described in Table 2.
• a lyocell multi-filament was prepared by the same process as example 3 and 4, only except for changing the temperature of the coagulation bath to 10 °C (for comp. ex. 3) and 15 °C (for comp. ex. 4) in order that the coagulation coefficient is 2.5 (for comp. ex. 3) and 2.0 (for comp. ex. 4). Physical properties of the obtained filament are described in Table 2.
• the Coefficient of Variation of section diameter (CV(%)) decreases. Meanwhile, the coagulation coefficient is more or less than 1, the Coefficient of Variation of section diameter (CV(%)) is 2.7 and 2.9 in each comparative example, meaning that non-homogeneity of the size of mono-filament is increased as shown in Table 2.
• the tenacity of multi-filament is reduced and the Coefficient of Variation of section diameter (CV(%)) is also increased, meaning that the homogeneity of the mono-filament is reduced.
• Examples 1 to 6 show the result of the Coefficient of Variation of section diameter (CV(%)) of lyocell multi-filament obtained by adjusting coagulation coefficient to 1. In reality, if the coagulation coefficient is adjusted to 0.8 to 1, a lyocell multi-filament with 2.5 or less in Coefficient of Variation of section diameter may be prepared.
• the lyocell fiber according to the present invention may have suitable properties for using as a dip cord for tire cord.
• the Coefficient of Variation of section diameter (CV(%)) of the lyocell fiber is an important factor to determine the fatigue resistance of tire-cord.
• the Coefficient of Variation of section diameter (CV(%)) may be controlled in the desired range by adjusting coagulation coefficient.
• the present invention has an advantage of producing a lyocell multi-filament for using as a dip cord for tire-cord.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Artificial Filaments (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
• Tires In General (AREA)

Applications Claiming Priority (2)

Publications (3)

Family

ID=39572509

Family Applications (1)

Country Status (6)

Families Citing this family (9)

Family Cites Families (19)

• 2006
  • 2006-12-28 KR KR1020060136132A patent/KR100824980B1/ko active IP Right Grant
• 2007
  • 2007-12-10 EP EP07851381A patent/EP2097562B1/en active Active
  • 2007-12-10 US US12/521,362 patent/US20110003148A1/en not_active Abandoned
  • 2007-12-10 WO PCT/KR2007/006410 patent/WO2008082092A1/en active Application Filing
  • 2007-12-10 JP JP2009542633A patent/JP4593676B2/ja active Active
  • 2007-12-10 CN CN200780048455.9A patent/CN101578401B/zh not_active Expired - Fee Related

Also Published As

Similar Documents

Legal Events