Classifications

• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
  • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
  • D02G3/44—Yarns or threads characterised by the purpose for which they are designed
  • D02G3/48—Tyre cords
• • 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
  • D01D5/12—Stretch-spinning methods
  • D01D5/16—Stretch-spinning methods using rollers, or like mechanical devices, e.g. snubbing pins
• • 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
  • D01F6/62—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters

Definitions

• the field of the invention is dimensionally stable yarns.
• Polyester multifilament yarns have found widespread use in various applications, and with increasing demands on mechanical performance of such fibers various high-strength polyester yarns have been developed with, among other improved parameters, relatively high modulus and relatively low free shrinkage.
• Nelson et al. describe in U.S. Pat. Nos. 5,067,538 and 5,234,764 methods and compositions for a polyester multifilament yarn having a dimensional stability of E 4 5 +FS of less than 11.5% and a terminal modulus of above about 20g/d. .
• Nelson 's yarns can typically be employed in environments with relatively high temperatures (here: 80-120°C).
• crystallization of the poly(ethylene terephthalate) (PET) in Nelson 's yarns appears to occur during spinning, thereby potentially rendering at least some of the desired mechanical qualities of the yarn independent from fluctuations during drawing.
• Rim et al. describe in U.S. Pat. No. 5,397,527 methods for producing a multifilament yarn fabricated from poly(ethylene naphthalate) (PEN) or other semi-crystalline polyester having a dimensional stability (EASL+Shrinkage) of less than 5% and a tenacity of at least 6.5g/d.
• Rim's yarns advantageously improve several mechanical qualities of previously known PEN yarns and may even be produced using equipment without high-speed spinning capability.
• the chemical composition of such yarns is typically limited to PEN or compositions with high quantities of PEN.
• U.S. Pat. No. 5,238,740 to Simons et al. a polyester yarn with a tenacity of at least lOg/d and a shrinkage of less than 8% is produced by passing the spun filaments through a heated and insulated column in which a particular temperature profile is employed in combination with relatively high take-up speeds to obtain the desired improved mechanical properties. While Simons' methods generally produce yarns with a relatively high tenacity and a relatively high secant modulus (greater than 150g/d/100%) at a comparably low shrinkage, relatively expensive equipment and additional process controls for the heated column are generally required.
• PET treated cords have been produced using Hoechst T748 with a DPF of 7.2, which exhibited similar fatigue resistance when compared to treated cords from a 4.8 DPF yam.
• Hoechst T748 with a DPF of 7.2, which exhibited similar fatigue resistance when compared to treated cords from a 4.8 DPF yam.
• yams include those having a fatigue strength retention FR, wherein the yam is spun and drawn such that FR increases when DPF increases.
• contemplated yams have a DPF of between about 10 and 20, and comprise a polyester, preferably poly(ethylene terephthalate). It is further contemplated that such ya s have a dimensional stability defined by E x + TS of no more than 12, more preferably of no more than 11, and that the increase in strength retention per DPF in the contemplated yams is no less than 1%.
• first generation yams have E x + TS in the range of 11-12, and later improved versions are lower.
• E x is the elongation at x stress for the yam, where x is 41 cN/tex or, for example, 45 N for 1100 decitex yam, 58 N for 1440 decitex yam, 67 N for 1650 decitex yam, and 89 for 2200 dtex yam.
• TS is thermal shrinkage.
• contemplated yams are twisted into a cord or twisted as single yams that are at least partially disposed within a rubber.
• a method of forming a yam has one step in which a polymeric material is provided and spun into a plurality of filaments.
• a dimensionally stable yam is drawn from the plurality of filaments, wherein the yam has a decitex per filament count DPF of at least 7.5 and a fatigue strength retention FR, and wherein the yam is spun and drawn such that FR increases when DPF increases.
• dimensionally stable yams with excellent fatigue resistance can be produced from a plurality of polymeric filaments with a DPF of at least 7.5.
• the yam is spun and drawn such that the fatigue strength retention of the yam increases when DPF increases.
• a yam with 11 decitex per filament was produced by extruding a polyester (most preferably poly(ethylene terephthal- ate)) from a spinneret into a plurality of individual filaments at a predetem ined extrusion rate (typically between about 25.0-80.0 kg/hr) into a gaseous delay zone .
• the filaments are subsequently solidified in a gaseous quenching column to form an undrawn dimensionally stable yam with a birefringence of between about 0.02 to about 0.15, and more preferably between about 0.05 to 0.09.
• the undrawn yam is then continuously transported to a series of draw rolls where it is drawn to within 85%, preferably within 90%, of its maximum draw ratio at yam temperatures between about 70°C and about 250°C.
• Typical processes and equipment are described in US Patent 5,630,976; US Patent 5,132,067; US Patent 4,867,936; and US Patent 4,851,172.
• particularly preferred polymers include various polyesters, and especially poly(ethylene terephthalate).
• the intrinsic viscosity of preferred polymers is at least 0.7, more typically at least between about 0.85 and about 0.98, and in some cases between about 0.99 and about 1.30, and even higher.
• the configuration of contemplated spinnerets used in the melt extrusion process will vary considerably. It is generally contemplated that the number of orifices in the spin pack is not limiting to the inventive subject matter and may thus be most typically between 20 and 150 for 1100 decitex yams and proportionate to achieve equal DPF for other decitex yams. However, where yarns with relatively low filament count are desirable, the number of orifices may be between 5 and 20. Similarly, where yams with relatively high filament count are desirable, the number of orifices may be between 200 and 400, and even more for higher decitex yarns.
• contemplated orifice diameter it is generally contemplated that numerous diameters are suitable for spinning contemplated fibers, and the choice of a particular diameter will depend at least in part on the desired physical properties of the fiber.
• contemplated orifice diameters include diameters between 0.8-2.3mm, and even more.
• Further exemplary suitable orifice parameters may be found in U.S. Patent No. 5,085,818 to Hamlyn et al, which is incorporated by reference herein.
• suitable polymeric multifilament yams need not be restricted to yams with 11 decitex/filament, but may also include a dimensionally stable polymeric multifilament yam having a decitex per fiber count DPF of at least 7.5, more preferably of at least 9, even more preferably of at least 10, and most preferably of at least 12, so long as contemplated polymeric multifilament yams are dimensionally stable.
• a dimensionally stable polymeric multifilament yams may have a DPF between 10 and 20.
• dimensionally stable yam as used herein means that suitable yarns will have a dimensional stability defined by E X +TS of no more than 12, and more preferably a dimensional stability defined by E X +TS of no more than 11.
• the filaments are spun into a delayed quench, and particularly contemplated that the temperatures of the gaseous atmosphere in the delayed quench are generally above 250°C.
• Solidification of the extruded filaments is preferably performed in an air quenching column at a quench rate of preferably between about 10mm (H 2 O) and about 70mm (H 2 O).
• a quench rate preferably between about 10mm (H 2 O) and about 70mm (H 2 O).
• numerous quench rates below 10mm (H 2 O) and above 70mm (H 2 O) are also suitable (e.g., 2-lOmm and less, or 70-120mm and even more)
• the undrawn yam that is formed by contemplated filaments will be a dimensionally stable yam precursor with a birefringence ⁇ n of at least 0.020, so long as such ⁇ n values are indicative of dimensional stability of at least first generation.
• an adhesion active overfmish may be applied to the undrawn yam, the drawn yam, or both.
• Typical adhesion active finish additives include polyglycidyl ethers (US Patents 4,462855; 4,557,967; and 5,547,755, all of which are incorporated by reference herein), multifunctional epoxy silanes (US Patent 4,348,517, incorporated by reference herein), and additives which form epoxides in situ (US Patent 4,929,760, incorporated by reference herein).
• contemplated undrawn yams are drawn in a series of draw rolls, and a typical draw configuration includes four to five roll pairs Z 1 -Z 5 .
• Zi may be heated to various temperatures, it is generally preferred that Zi is heated to between about 20°C and 120°C, more preferably between about 40°C and 80°C.
• Temperature of Z 3 may vary widely from 60°C to 250°C depending on whether Z 4 has much higher speed (stretching between rolls) or similar speed (primarily heat-setting between rolls). Lower temperatures are preferred where substantial additional stretching occurs between the rolls.
• Z 4 for 4- roll pair panel
• Z 5 (5 roll pair panel)
• preferred temperatures are in the range of about 120°C to 160°C.
• Contemplated draw ratios of the multifilament fibers will typically be in the range of about 1.2- 2.5. Further especially suitable materials and spinning/drawing conditions are described in U.S. Pat. Nos. 5,067,538 and 5,234,764 to Nelson, both of which are incorporated by reference herein.
• contemplated yams may be twisted into cords of various configurations using procedures and equipment well known in the art.
• contemplated configurations include 1100/2 decitex cords with relatively low twist of between 270 x 270 to 320 x 320 to cords with relatively high twist of between 420 x 420 to 470 x 470 (and even higher).
• Equivalent twists for other deniers can be determined by keeping the twist multiplier constant (Sqrt(nominal cord decitex) x twist(tpm)).
• a method of forming a yam may comprise a step in which a polymeric material is provided and a plurality of filaments is spun from the polymeric material.
• a dimensionally stable yam is drawn from the plurality of filaments, wherein the yam has a decitex per fiber count DPF of at least 7.5 and a fatigue strength retention FR, wherein the ya is spun and drawn such that FR increases when DPF increases.
• Such prepared cords may find use in numerous applications and products, and particularly suitable applications and products include power transmission belts, automobile tires, safety belts, parachute harnesses and lines, cargo handling and safety nets, etc.
• a 1100 decitex polyester (here: PET) yam with 11 decitex/filament was produced by extmding one hundred individual filaments through 0.762mm spinneret holes at 33.5 kg/hr into a 5.08cm heated sleeve at 450°C, followed by solidifying into an air quenching column.
• the so produced undrawn yam had a birefringence of 0.083, which is characteristic of dimensional stability of at least second generation.
• the undrawn yam was continuously transported to a series of draw rolls and drawn under conditions as summarized in Table 1 to yield a yam having the properties as listed in Table 2.
• An adhesive overfmish was applied to the yam after the drawing step and the yam was twisted into 1100/2 cords of different twist as indicated in below.
• An adhesive coating application was then performed by dip coating the cord in ammoniated resorcinol formaldehyde adhesive, followed by subsequent stretching in a first oven at room temperature at 2.4N for 10 sec, in a second oven at room temperature at 2.4N for 10 sec, in a third oven at 177°C at 2.4N for 30 sec, and in a fourth oven at 240°C at a tension and time sufficient to obtain desired shrinkage of between about 1.0% to 2.0%, more preferably 1.4% to 1.8%, and most preferably about 1.6% (tension and time will have to be adjusted for a particular denier).
• the 11 decitex/filament yam as described above was twisted into (a) 1100/2 cords of 470*470 twist (twist multiplier is 22043) having a treated cord strength retention of at least 96% absolute, (b) 1100/2 cords of 440*440 twist (twist multiplier is 20636) having a treated cord strength retention of at least 85% absolute, and (c) 1100/2 cords of 400*400 twist (twist multiplier is 18760) having a treated cord strength retention of at least 70% absolute.
• especially contemplated products include those comprising a dimensionally stable polymeric multifilament yam having a decitex per filament of at least 7.5 and a treated cord strength retention of at least 70% absolute for a twist multiplier of 18760, a treated cord strength retention of at least 85%) absolute for a twist multiplier of 20636, or a treated cord strength retention of at least 96% absolute for a twist multiplier of 22043.
• products may be fabricated that include a dimensionally stable polymeric multifilament yam having a decitex per fiber count DPF of at least 7.5.
• Preferred multifilament yams comprise a polyester (e.g., PET) and will have a DPF between 10 and 20.
• PET e.g., PET
• contemplated yams are presented herein (e.g., the yam is twisted in a 2-ply cord with a twist (single x cable TPM) of 320 x 320 to 470 x 470 for an 1100 decitex ya ), it should be appreciated that alternative cord constructions with equal twist multipliers are also contemplated.
• the 11 decitex/filament yam as described above was twisted into 1100/2 cords of 420X420.
• An adhesive treating condition identical to the coating process described above was employed, and treated cord strength retention was determined as described below.
• the treated cord properties and fatigue results are depicted below in Table 5, in which the 1100/2 cords 420X420 twist (Example 2) are compared to treated cords prepared using the same protocol to form a 5.5 decitex/filament yam (Honeywell 1X53-200 filaments - Experimental) and a 3.7 decitex/filament yam (Honeywell 1X53-300 filaments - Comparative [reference yam]), which was prepared as internal standard.
• contemplated products will include a dimensionally stable polymeric multifilament yam having a decitex per fiber count DPF of at least 7.5 and a fatigue strength retention FR, wherein the yam is spun and drawn such that when DPF increases at least 100% over a reference yam, FR increases at least 19% absolute over the reference yam, and wherein the reference yam has a fatigue strength retention of 64% and a DPF of 3.7 with a twist multiplier of 19700 (the reference yam is commercially available Honeywell 1X53-300 filaments, see "Comparative" above).
• the test conditions as described below apply.
• dimensionally stable polymeric yams may have a decitex per filament of at least 7.5 and a treated cord strength retention of at least 70% absolute for a twist multiplier of approximately 18760, more preferably a decitex per filament of at least 7.5 and a treated cord strength retention of at least 85% absolute for a twist multiplier of approximately 20636, and most preferably a decitex per filament of at least 7.5 and a treated cord strength retention of at least 96% absolute for a twist multiplier of approximately 22043, wherein the term "twist multiplier" as used herein is defined as sqrt (nominal cord decitex) * twist in TPM.
• twists are also contemplated and include twists between 320 and 470, especially for an 1100 decitex yam.
• contemplated yams (and particularly yams fabricated from poly(ethylene terephthalate), which preferably have a DPF of between about 10 and 20) are spun and drawn such that the fatigue strength increases as DPF increases (e.g. , with a fatigue strength retention increase per DPF of no less than 1%).
• FR decreases as DPF increases (e.g., due to skin-core effect during quenching)
• the inventors surprisingly found that yams can be spun such that when DPF increases at least 100% over a reference yam having a DPF of 3.7 and a fatigue strength retention of 64%o, FR will increase at least 19% absolute over the reference ya .
• dimensionally stable yams can be spun and drawn such that the FR increases when DPF increases.
• XN were determined following standard procedures on the yam using a Statimat type FPM/M instrument, and on the treated cord using an Instron type 4466 (ASTM: D885-84). The distance between the jaws is 254mm and the traction speed is 305mm/min.
• Thermal shrinkage was determined using a Testrite (Model NK5) instient with the following procedure: To one end of the sample, a weight equal to ((decitex)x0.05g) is attached, and the sample is transferred into the instmment at the desired temperature for 120sec. Dimensional stability is expressed as the sum of the elongation at x N and thermal shrinkage at 177°C for the yams.
• the treated cord strength retention was evaluated in a flex fatigue endurance test as follows (3-step procedure including (1) sample preparation, (2) endurance test, and (3) measurement of strength and calculation):
• Sample preparation The flex samples are prepared in a sandwich made with mbber, Kevlar, polyester and treated cord. The dimension of the sample is 17.5cm X 51cm with 9 different layers as follows: Rubber (2.2mm) + mbber (0.43mm) + Kevlar layer + mbber (0.43mm) + polyester film + mbber (0.43mm) + treated cord polyester under study putting in parallel to cover all the sample surface (28 ends/2.54cm) + mbber (0.43mm) + Rubber (0.9mm).
• the sample prepared is vulcanized at 171°C for 20 minutes under a load of 78.5N. After the vulcanization the sample are kept at room temperature before the flexing endurance test. The sample is cut into five samples of 2.54cm width. The sample from the middle is kept at room temperature as reference while the remaining four samples are submitted to the flex endurance test.
• Flex endurance test The 4 samples are put on the 4 pulley of 15mm diameter. A load of 70kg is adjusted for each sample.
• the flex fatigue machine is programmable articulated machine. When the machine is started, the samples are flexing around the pulley with frequency of 200 cycles/min for 30000 cycles. When the endurance cycles are finished, the samples are moved out off the pulleys and are being kept for a minimum of 12 hours at room temperature.
• Measuring and calculation Five cords are taken from the middle of each of the four samples and tested with Instron to determine the strength of each cord. Similarly, five cords are taken from the middle of the reference sample and tested as above. The retention is determined by dividing the average of 20 treated cord strengths after the endurance test by the average of 5 treated cord strengths kept as the reference.
• Birefringence test Birefringence was measured with a BEREK compensator (206 IK from Leitz) using the darkest band available.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)

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Citations (9)

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• 2002
  • 2002-01-29 CN CN02821550.8A patent/CN100572625C/zh not_active Expired - Fee Related
  • 2002-01-29 CZ CZ20040615A patent/CZ302323B6/cs not_active IP Right Cessation
  • 2002-01-29 EP EP02713509A patent/EP1470275A4/en not_active Withdrawn
  • 2002-01-29 MX MXPA04007087A patent/MXPA04007087A/es not_active Application Discontinuation
  • 2002-01-29 WO PCT/US2002/002751 patent/WO2003064744A1/en active Application Filing

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