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
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/78—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products
  • D01F6/84—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products from copolyesters

Definitions

• This invention relates to a new process for preparing new polyester yarns, and more particularly new feed yarns of cationic dyeable polyester spin-oriented filaments that are especially suitable for processing by draw-warping into new flat yarns that provide soft pleasing fabrics whose aesthetics can be further improved by napping.
• polyester textile yarns are used for many widely-differing articles of apparel requiring polyester yarns in several different forms, and correspondingly manufactured by different processing techniques.
• polyester apparel yarns there are two main categories of polyester apparel yarns, namely spun yarns (from polyester staple fiber, with which the present invention is not concerned) and multifilament (continuous filament) yarns which, themselves, again comprise two main categories, i.e., textured yarns (whose filaments are crimped, usually by false-twisting, with which the present invention is not concerned) and flat (i.e., untextured) yarns.
• the present invention is concerned with flat multifilament polyester yarns.
• polyester polymers including copolymers
• poly(ethylene terephthalate) which is often referred to as homopolymer.
• Homopolymer has generally been preferred over copolymers because of its lower cost, and also because its properties have been entirely adequate, or even preferred, for most end-uses.
• Homopolymer is often referred to as 2G-T.
• Poly[ethylene terephthalate/5-sodium-sulfo-isophthalate] copolyester has, however, also been manufactured and used commercially in considerable quantities for some thirty years, especially for staple, and such copolyester filaments and yarns were first suggested by Griffing and Remington in U.S. Patent No.
• a very desirable feature of this copolyester is its affinity for cationic dyes.
• An example of a prior suggestion for using spin-oriented multilobal filaments of this copolyester as a draw-texturing feed yarn is in Example VI of Duncan and Scrivener, U.S. Patent No. 4,041,689. As explained in copending application Serial No.
• the present invention concerns the preparation of new polyester feed yarns of these cationic dyeable copolymer filaments, sometimes referred to as (2G-T/SSI), that are especially suited for warp-drawing to provide new flat yarns that are described herein.
• Such yarns may consist essentially only of such cationic dyeable filaments, or may be heather yarns that are cospun with homopolymer filaments (2G-T) as well.
• the yarns should desirably have an average interlace level of about 5.5 to about 9.5 RPC, and preferably less than about 7.5 RPC, and be provided with a finish that is stable enough to persist on such yarn after draw-warping in sufficient quantity and in such condition as to provide finish to enhance knitting performance.
• the resulting flat multifilament interlaced textile yarn are of poly[ethylene terephthalate/5-sodium-sulfo-isophthalate] copolyester filaments containing about 2 mole % of ethylene 5-sodium-sulfo-isophthalate repeat units, being of denier about 20 to about 150, and preferably of denier at least about 40, and having a tenacity of about 1.5 to about 2.5 grams per denier, and preferably about 1.8 to about 2.2 grams per denier, in other words about 2 gpd, and elongation to break of about 10 to about 50%, preferably about 20 to about 40%, and preferably of relatively low modulus, preferably of about 40 to about 60 grams per denier, of boil-off shrinkage about 2 to about 10%, and preferably about 3 to about 7%, and especially about 5 to about 7%, and preferably a dry heat shrinkage, measured at 160°C, of about 4 to about 15%.
• the flat yarns of the invention also have a surprising advantage in their uniformity, which can be indicated as a low standard deviation for the boil-off shrinkage, generally less than about 1%, and preferably less than about 0.25%, which contrasts favorably with prior flat copolyester yarns that have been available commercially, unless special measures are taken to improve this uniformity, which increases the cost.
• one aspect of the present invention relates to yarns consisting essentially of cationic dyeable filaments (i.e. of 2G-T/SSI copolyester), while another relates to cospinning heather yarns from the copolyester and from homopolymer (2G-T) so as to provide a mixed filament yarn with filaments that dye differently.
• the lower spinning speeds provide advantages downstream, as indicated, for both types of filaments.
• the important point for making a yarn for napping is to provide a feed yarn that will spin and process well until the time that it is desired to do the napping or brushing.
• a low degree of interlace i.e., a relatively high RPC
• a high degree of interlace a low RPC
• any such value is an average value, since the interlace may vary widely along any individual end, so, herein, all references to interlace RPC are to the average of at least 100 measurements, and preferably an even higher number.
• interlace levels are averages; thus, in practice, there is likely to be a variation of the degree of interlace; so there may be some portions of any yarns with undesirably low degrees of interlace, corresponding to what could ( if such low degree would have been maintained throughout the whole yarn) have been suitable for a DTFY.
• a high degree of interlace is required because, after draw-warping (which will extend the distance between the interlace nodes, i.e., raise the RPC and lower the degree of interlace) the amount of interlace should be such as is desired for further processing of the drawn yarns, usually in fabric formation, e.g., by warp knitting.
• the degree of interlace be such that the (average) RPC be less than about 9.5, and it will generally be preferred to have an even higher degree of interlace, as shown by a value of less than about 7.5.
• the precise amount of interlace will generally depend on what is desirable in the final fabric containing the drawn yarns, especially for aesthetic purposes. It is generally difficult to obtain a degree of interlace higher than is indicated by a value of about 5.5 RPC at the high withdrawal speeds of the order of 3000 ypm that are used herein. This higher interlace is obtained most conveniently in practice by increasing the air pressure used for interlacing.
• DTFY has preferably been spun using a 2-godet system, as shown, for example, in Knox, U.S. Patent No. 4,156,071.
• Some manufacturers have preferred a godet-less system for DTFY, but this is not recommended for preparing draw-warping feed yarns according to the present invention. Indeed, we prefer to provide additional godets to prevent threadline slippage and allow interlacing at relatively lower tension without damaging filaments.
• draw-warping feed yarns Another important consideration for draw-warping feed yarns, according to the present invention, is in relation to the finish. It has been customary to provide all filament yarns (as-spun) with a coating, generally referred to as a (spin-)finish, since the provision of such finish is generally the first contact of any freshly-extruded filament with any solid material, i.e., with anything other than the quenching air or any casual contact with a guide, which is usually undesirable before application of the spin-finish.
• the feed yarn with a finish that should preferably be stable enough to persist on such yarn even after it has been draw-warped, and it should preferably persist in sufficient quantity and in such condition as to provide finish to enhance the subsequent processing of the drawn yarn, usually knitting to form the desired fabric.
• a spin-finish has been to maximize draw-texturing performance, as mentioned, e.g., by Piazza and Reese in U.S. Patent No. 3,772,872, and in other publications discussing the importance of providing the optimum properties for processing on a draw-texturing machine.
• a preferred finish for such draw-warping feed yarns consists of a major amount of low volatility ester, lesser amount of low volatility emulsifiers, up to about 10% of mixed antistat components, a minor, but effective amount of alkoxylated polydimethylsiloxane or perfluorinated alcohol-derived wetting agent; and a minor, but effective amount of antioxidant.
• Such finishes preferably have a viscosity between about 50 and 200 centipoise at 25°C, a smoke point of greater than 140°C, and volatility less than 30% at 200°C and less than 15% at 180°C, when a 1.0 gram sample is exposed in a forced draft oven for 120 minutes.
• an acceptable finish used for such draw-warping feed yarns is "Lurol 2233", available from the George A. Goulston Company, 700 N. Johnson Street, Monroe, NC 28110.
• Draw-warping is a process that has achieved considerable technical and commercial interest in recent years, because of its commercial advantages, and has been described in many publications, including Seaborn, U.S. Patent No. 4,407,767, and by Frank Hunter in Fiber World, September, 1984, pages 61-68, in articles in Textile Month, May, 1984, pages 48-50 and March, 1985, page 17, and in Textile World, May, 1985, page 53, and in other articles, including the February, 1985, issue of Chemiefasern/Texteilindustrie, and there are several commercial firms offering commercial draw-warping machines and systems, who have provided literature and patents.
• draw-warping is already known to those skilled in the art.
• Various terms, such as “warp-drawing” and “draw-beaming” have been used additionally, but, primarily, herein, the term “draw-warping” is used.
• All of the feed yarns according to the invention were of 2G-T/SSI copolyester as such or cospun with 2G-T, and were spin-oriented filaments prepared by high speed spinning as described herein at withdrawal speeds of about 2800-2900 ypm. Most of the properties herein are measured as described in Knox U.S. Patent No. 4,156,071, the method for determining LRV is disclosed in Most, U.S. Patent No. 4,444,710, and the interlace pin count is measured by the device described by Hitt in U.S. Patent No. 3,290,932.
• a 90 denier (100 dtex), clear, copolyester feed yarn was prepared for draw warping according to the invention with high interlace and a suitable finish, as described hereinbefore. Feed yarn properties are given in Table IA.
• This feed yarn was draw warped at 1.51 draw ratio in various different arrangements on both a Karl Mayer draw warper and a Barmag draw warper: on the Mayer equipment with a stationary hot draw pin, on the Barmag equipment using the relax plate for heat setting and on the Barmag equipment using the standard set plate for heat setting.
• Process conditions speed, set plate temperature, and overfeed
• Each process gave textile yarns having desirably low boil off shrinkages and tenacity values while keeping the elongation to break adequately high.
• the tenacities of the resulting flat (textile) yarns ranged from 1.9 to 2.4 gpd, being mostly from 2.0 to 2.3 gpd, with elongations of from 25 to 35%, and modulus from 45 to 60 gpd, boil-off shrinkage generally about 5% (with one at 7.8% and another at 5.9%) and excellent shrinkage uniformity as shown by a standard deviation of less than 1% and mostly less than 0.25%, and dry heat shrinkages (160°C) mostly less than about 7%, with one value at about 9%.
• Higher tenacity (with lower elongation) can be obtained by using higher draw ratios, but this will tend to reduce the knitting and napping performance of the resulting yarn.
• Lower tenacity and higher elongations can be obtained at lower draw ratios, but this will result at some point in high denier spread and fabric defects.
• a 175 denier, clear copolyester feed yarn was produced in essentially similar manner and draw warped on a Karl Mayer draw warper. Feed yarn properties are in Table II.
• This feed yarn was draw warped at 1.51 draw ratio on a Karl Mayer draw warper using an unheated rolling pin for draw instead of the standard hot stationary draw pin, and the same ranges for process variables (speed, set plate temperature and overfeed) as in Example 1.
• the roll temperature was kept constant at 85°C and the predraw plate heater was turned off.
• the resulting flat textile yarns had tenacities of from 2.0 to 2.3, with one at 2.4 gpd with elongations between 35 and 45%, and modulus from about 45 to 55 gpd, and boil-off shrinkages again about 5% or less, with one value at 7.6%, and another at 5.8%, and good shrinkage uniformity, as shown by a standard deviation of 1% or less and several about 2-5% or less, and likewise low dry heat shrinkages (160°C) of less than 9% and generally 7% or less.
• a 60 denier, semi-dull, copolyester feed yarn for draw warping was produced on existing DTFY spinning equipment and draw warped on a Mayer draw warper.
• the feed yarn had the following properties:
• the draw warping conditions were as follows: The drawn yarn properties resulted:
• the yarn gave good draw warping performance with a defect level of only 0.09 D/MEY. Since a volatile spin finish was used on the feed yarn, an overlube was applied during draw warping to provide additional protection for knitting. According to the invention, however, low fuming, non volatile finishes such as described hereafter, are preferred to be applied during spinning so that exhaust hoods and overlubing will not be required during draw warping.
• Feed yarns (of 115 denier, 34 filaments) were cospun at 2900 ypm and 3200 ypm (17 filaments of 2G-T/SSI copolyester and 17 filaments of 2G-T homopolymer) and then draw-warped on a Karl Mayer draw-warper for purposes of comparison, and the resulting comparative data is given in the following Table:-
• QB/M are the numbers of quality breaks per thousand pounds of yarn spun, and the defects/set are the numbers of defects over 4 beams, so the improvement obtained by reducing the withdrawal speed from 3200 to less than about 3000 ypm is clearly apparent.
• the polymer may contain additives, such as TiO2, which is a conventional additive, and variation of the TiO2 content can be used to differentiate the luster of the filaments, e.g., from clear through semi-dull to matte.
• suitable contents of TiO2 may vary from about 0 up to about 2%.
• other additives may be included.
• the 2G-T/SSI copolyester has contained about 2 mole % of 5-sodium-sulfo-isophthalate residues, instead of terephthalate residues, the precise amount may be varied, as taught in the art, to obtain more or less affinity for cationic dyestuffs, and so a deeper or lighter dyeing in the eventual filaments, or to obtain other results that may be advantageous from this variation.
• Other variations may be made to the preparation or processing of the filaments and yarns, even if this has not been specifically disclosed in the Examples herein. It may also be advantageous to use mixtures of cross-sections and deniers for aesthetic or other purposes.

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

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Citations (3)

• 1990
  • 1990-04-20 EP EP90304266A patent/EP0453664A1/fr not_active Withdrawn

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