Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H3/00—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length
  • D04H3/08—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating
  • D04H3/16—Non-woven fabrics formed wholly or mainly of yarns or like filamentary material of substantial length characterised by the method of strengthening or consolidating with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion
• • 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
  • D01D5/098—Melt spinning methods with simultaneous stretching
  • D01D5/0985—Melt spinning methods with simultaneous stretching by means of a flowing gas (e.g. melt-blowing)
• • 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
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/76—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from other polycondensation products
  • D01F6/765—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from other polycondensation products from polyarylene sulfides

Definitions

• the present invention relates to the production of polyphenylene sulfide fibers and products including the same.
• Filtration processes are used to separate compounds of one phase from a fluid stream of another phase by passing the fluid stream through filtration media, which traps the entrained or suspended matter.
• the fluid stream may be either a liquid stream containing a solid particulate or a gas stream containing a liquid or solid aerosol.
• bags are used in collecting dust emitted from incinerators, coal fired boilers, metal melting furnaces and the like. Such filters are referred to generally as "bag filters.” Because exhaust gas temperatures can be high, bag filters used to collect hot dust emitted from these and similar devices are required to be heat resistant. Bag filters can also be used in chemically corrosive environments. Thus, dust collection environments can also require a filter bag made of materials that exhibit chemical resistance. Examples of common filtration media include fabrics formed of aramid fibers, polyimide fibers, fluorine fibers and glass fibers.
• PPS polymers exhibit thermal and chemical resistance.
• PPS polymers can be useful in various applications.
• PPS can be useful in the manufacture of molded components for automobiles, electrical and electronic devices, industrial/mechanical products, consumer products, and the like.
• PPS has also been proposed for use as fibers for filtration media, flame resistant articles, and high performance composites. Despite the advantages of the polymer, however, there are difficulties associated with the production of fibers from PPS.
• PPS fibers from a spunbond process It is difficult to spin PPS fibers from a spunbond process over a commercially useful period of time.
• Commercially available PPS resins have either too low or too high of a viscosity for a spunbond process.
• a low viscosity PPS resin creates excessive breaks in the fibers and defects in the spunbond web.
• a high viscosity PPS resin creates too much torque in the extruder making the resin unspinnable.
• the present invention provides a commercially viable process to make spunbond polyphenylene sulfide fiber.
• the present invention is directed to a spunbond fiber comprising polyphenylene sulfide polymer having a zero shear viscosity at 300 0 C of about 21 ,500 to about 28,000 Pa s.
• the present invention is directed to a spunbond fiber comprising polyphenylene sulfide polymer having a specific zero shear viscosity which allows extended spinning runs with minimal spinning defects. It was found that spunbond PPS fibers can be made using polyphenylene sulfide polymer having a zero shear viscosity at 300 0 C of about 21 ,500 to about 28,000 Pa s. Because PPS resin having a zero shear viscosity at 300°C of about
• a zero shear viscosity at 300 0 C of about 21 ,500 to about 28,000 Pa s is adequate for the invention, a shear viscosity at 300°C of about 22,500 to about 27,000 Pa-s is preferred and a shear viscosity at 300 0 C of about 23,500 to about 26,000 Pa-s is most preferred.
• PPS fibers of the invention can have average fiber diameters of less than about 50 micrometers and more preferably less than about 20 micrometers.
• the fibers generally have substantially round cross sections, but other cross sections such as multi-lobal cross sections could be made as would be known to one of ordinary skill in the art.
• the spunbond fibers of the invention are typically collected into a web on a collector or screen. In one particularly advantageous aspect of the invention, the web is used to produce filtration media.
• the fibers of the invention can exhibit good thermal and chemical resistance.
• the fibers can also exhibit good flexibility and tensile strength and can be manipulated to produce products for use in corrosive and/or high temperature environments.
• Zero Shear Viscosity was calculated as follows. The viscosity of Fortran PPS 0309 C4 and Fortran PPS 0317 C1 were measured individually at several different shear rates at 300°C. The viscosity at zero shear is then extrapolated from the viscosity data. The viscosity of the blends is then approximated using the equation below which is derived from the Arrhenius equation relating viscosity with polymer concentration:
• log Viscosity (b iend) (n log Viscosity (P oiymeM) + (100-n) log Viscosity (P oiymer 2)) / 100
• Fiber Diameter was determined as follows. A bundle of fibers were carefully collected just below the attenuating jet. The fiber bundle was then prepared for viewing under an optical microscope. A digital image of the fiber bundle was then captured and with the aid of computer. The diameter of at least thirty (30) clearly distinguishable fine fibers were measured from the photographs and recorded. Defects were not included (i.e., lumps of fine fibers, polymer drops, intersections of fine fibers). The average (mean) fiber diameter for each sample was calculated.
• a spunbond fabric was made from polyphenylene sulfide.
• the polyphenylene sulfide component has a melt flow index of 101 g /10 min at 316°C under a load of 2.16 kg and is available from
• Ticona as Fortran® PPS 0309 C1.
• the zero shear viscosity for this resin, measured at 300 0 C is calculated to be 21 ,000 Pa s.
• the polyphenylene sulfide resin was dried in a through air dryer at a temperature of 1 15°C, to a moisture content of less than 150 parts per million.
• the polyphenylene sulfide resin was heated to 295°C then metered to a spin-pack assembly where the melt stream was filtered and then distributed through a stack of distribution plates to provide multiple raws of spunbond fibers having a circular cross section.
• the spin pack assembly consisted of 4316 round capillary openings (155 rows where the number of capillaries vary from 22 to 28). Each capillary has a diameter of 0.35 mm and a length of 1 .40 mm. The width of the pack in the machine direction was 18.02 cm and in the cross direction was 1 15.09 cm.
• the spin pack assembly was heated to 295°C and the polymer was spun through each capillary at a polymer throughput rate of 1 .0 g/hole/min.
• the fibers were cooled in a cross flow quench extending over a length of 122 cm.
• An attenuating force was provided to the bundle of fibers by a rectangular slot jet. The maximum attainable jet pressure while maintaining a spinning process was 70.3 kPa.
• the distance from the spin-pack to the entrance of the jet was 92.45 cm.
• the fibers exiting the jet were collected on a forming belt.
• a vacuum was applied underneath the belt to help pin the fibers to the belt.
• the spunbond layer was then thermally bonded between an embosser roll and an anvil roll.
• the bonding conditions were 148°C roll temperature and 300 pli nip pressure.
• the spunbond sheet was formed into a roll using a winder. The process was characterized by numerous broken filaments occurring across the entire width of the spinneret face. These broken filaments were found in the sheet product and because of their size and different melting behavior; the physical and barrier properties of the sheet material would be negatively impacted.
• Example 1 was prepared similarly to Comparative Example A except the Ticona resin Fortran® PPS 0309 C1 was modified by the addition of Ticona resin Fortran® PPS 0317 C1.
• Fortran PPS 0317 C1 has a zero shear viscosity measured at 300 0 C that is calculated to be 31850 Pa*s.
• Fortran® PPS 0317 C1 was homogeneously blended into the Fortran® PPS 0309 C1 at a loading of 10% by weight and introduced at the throat of the extruder to raise the zero shear viscosity, measured at 300°C, to a calculated value of 22800 Pa*s.
• the maximum attainable jet pressure while maintaining a spinning process was 134.4 kPa. Although broken filaments were still observed, the number and frequency was greatly reduced. The process would run stably for about an hour or two before needing to be shut down to dress the jet or spinneret face.
• Fiber spinning conditions spinning performance and properties are listed in the Table.
• Example 2 was prepared similarly to Example 1 except the Fortran® PPS 0317 C1 was homogeneously blended into the Fortran® PPS 0309 C1 at a loading of 30% by weight.
• the maximum attainable jet pressure while maintaining a spinning process was 133.1 kPa. No broken filaments were observed during spinning and the process ran uninterrupted for more that six (6) hours. Fiber spinning conditions, spinning performance and properties are listed in the Table.
• Example 3 was prepared similarly to Example 2 except the highest jet pressure attainable while maintaining the stable fiber spinning was found to be 209.6 kPa. No broken filaments were observed during spinning and the process ran uninterrupted for more that six (6) hours. Fiber spinning conditions, spinning performance and properties are listed in the Table.
• Example 4 was prepared similarly to Example 3 except the throughput was reduced to 0.8 ghm. Broken filaments were observed, their numbers, however, were greatly reduced and the frequency of the occurrence was intermittent. The process would run stably for about four (4) hours before needing to be shut down to dress the jet or the spinneret face. Fiber spinning conditions, spinning performance and properties are listed in the Table. Comparative Example B

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• 2008
  • 2008-12-18 EP EP08866278A patent/EP2235243A1/de not_active Withdrawn
  • 2008-12-18 WO PCT/US2008/087332 patent/WO2009085897A1/en active Application Filing
  • 2008-12-18 JP JP2010539773A patent/JP2011508099A/ja active Pending
  • 2008-12-18 CN CN2008801213489A patent/CN101903576A/zh active Pending

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