SPANDEX SUPPLY PACKAGE

Abstract: An improved spandex supply package (10) and a process therefore are provided. The package has a cylindrical core (20) on which spandex having a lubricating finish on its surface is wound. The last few hundred meters of the wound-up spandex (40), which constitute about 0.1 to 0.5 % of the total length of spandex wound-up in the package, has less than half the amount of finish on its surface than does the remainder of the wound-up spandex in the package.

Description: TITLE Spandex Supply Package BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a spandex supply package which contains spandex that has a lubricating finish and is wound up on a cylindrical core. More particularly, the invention concerns such a supply package wherein the amount of lubricating finish on the outer windings of spandex is considerably less than the amount of lubricating finish on the rest of the wound-up spandex. As a result of the decreased amount of lubricant on the surface of the outer windings, the stability of the package, especially with regard to sloughing-off of yarn from the package shoulders during shipping and handling, is greatly reduced. Description of the Prior Art Spandex is a manufactured fiber in which the fiber-forming substance is a long chain synthetic polymer comprised of at least 85% by weight of a segmented polyurethane. Most spandex is produced by dry spinning techniques and inherently is quite tacky. To avoid adherence of the spandex to itself when wound up in a supply package, as well as to avoid other problems in subseqent use of the spandex, lubricating finishes, such as silicone oils, are applied to the surface of the spandex prior to windup. Typically, the weight of the finish on the spandex amounts to in the range of 2 to 10% of the weight of the spandex. To form a spandex supply package, such as a bobbin, cake, cheese, pirn or the like, spandex is wound up on a cylindrical core. Equipment for this purpose is well known. For example, United States Patents 4,398,676 (Koppen et al) , 3,701,490 (Wray) and 3,409,238 (Campbell et al) , among others, disclose apparatus for high speed winding of spandex threadlines onto tubular cores to form spandex supply packages. However, during shipping and handling of such supply packages difficultes are sometimes encountered. For example, the spandex sometimes slides off the shoulders (i.e., the spandex near the flat circular faces) of the wound-up packages. Also, if the package is held horizontally during shipment, the spandex sometimes can unravel (or "piddle") from the package surface and fall to the bottom of the shipping container. Similarly, the spandex sometimes piddles onto the floor as the package is removed from the shipping container. The sloughing off of spandex from the shoulders of a supply package creates time-consuming difficulties and waste, especially in further textile operations, such as beaming, warping, knitting, weaving, mechanical covering of the spandex, air-jet entangling with other yarns and the like. Lubricating finishes for spandex and equipment for applying the finish to the spandex are well known. For example, U. S. Patent 3,296,063 (Chandler) discloses certain polysiloxanes as suitable finishes for spandex. Japanese Patent Application Publication 63-66073 (Maruyama et al) describes a polyurethane elastic yarn supply package in the form of a cheese, in which the amount of finish applied to the yarn depends on the apparent elongation of the yarn within the cheese. The amount of finish generally is less on the yarns near the center of the yarn package than on the yarns near the outside of the package. Among the numerous conventional techniques used to apply the lubricating finishes to the surfaces of moving spandex threadlines just before their windup into a supply package, are dipping, padding, spraying and the like. Known devices for applying such finishes to spandex include oiling rollers, atomizers, and the like. An object of the present invention is to eliminate, or at least greatly ameliorate, the problem of spandex sloughing off supply packages. SUMMARY OF THE INVENTION The present inventor found an unexpected relationship between the problem of spandex sloughing off supply packages and the amount of lubrication on the last few hundred meters of spandex wound up on the supply package. With the discovery of this surprising relationship, the present inventor was able to satisfy the object of the invention. The above-noted prior art apparently did not recognize any relationship between the sloughing-off problem and the amount of lubricating finish on the spandex, and had not addressed the problem. The present invention provides a spandex supply package in which the spandex is wound up on a cylindrical core and the spandex has a lubricating finish on its surface. For decreased sloughing off of the spandex from the package, at least the last 100 meters, preferab ly the last 500 meters, of the wound up spandex has a decreased amount of finish on the surface, the amount being less than one-half the average amount of finish on the surface of the spandex in the supply package. Preferably, the weight of finish on the length of spandex having the decreased amount of finish is in the range of 0.2 to 2% based on the total weight of the spandex. Preferably, the length of spandex having the decreased amount of finish constitutes in the range of 0.1 to 0.5% of the total length of spandex wound up in the package. The invention also includes a simple method for producing the improved spandex yarn supply package. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood by reference to the drawings which depict a typical spandex supply package of the invention. In Fig. 1, an isometric drawing, and in Fig. 2, a side view, of the supply package, spandex 10 is wound on a cylindrical core, tube 20. Faces 30 represent the edges of the package. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The following descriptions of preferred embodiments of the invention are included for purposes of illustration and are not intended to limit the scope of the invention. The scope is defined by the appended claims. Spandex yarn supply packages come in a variety of sizes. A typical commercial spandex supply package has the spandex 10 helically wound up on a cylindrical tube core 20. The core has a length L and an outer diameter, d, each of 4-inches (10.2 cm) . Spandex 10 forms a wound up unit 15, centrally located along the length of core 20. Wound up unit 15 has has an outer diameter D of 6 inches (15.2 cm), and a height H of 3.5 inches. Such a typical package holds 1.1 pounds (0.5 Kg) of spandex. The total length of spandex in such a package, of course depends on the denier (dtex) of the spandex. For example, a 0.5-Kg package of spandex would contain 450,000 meters of 10 denier (1.1 dtex) spandex or 112,500 meters of 40 den (44 dtex) spandex. Typical spandex supply packages have a silicone lubricating finish on the surface of the spandex. The lubricating finish nominally weighs between about 3 to 10% of the total weight of the spandex. Commonly, the finish averages about 4.5 % by total weight of the spandex. In accordance with the invention, to the decreasing of the amount of lubricating finish applied to the last of the spandex before it is wound up on a cylindrical member to form a package increases the friction sufficiently that the spandex no longer sloughs off the shoulders of the package. The spandex is much easier to pull through during preparation for beaming, and less tangling is observed during backwinding for all downstream processing because the shoulders are stable. This invention can be applied to all commercial spandex deniers, from 10 denier and below to 2240 denier and above. Approximately 500 to 2000 turns of reduced finish spandex are needed to stabilize the outside of the spandex package. The point at which the finish supply is turned off (number of meters from the end of the package) will depend on the size (circumference) of the package and the size of the fiber. The critical portion of the package that requires stabilization is between 1/16 inch and 1/4 inch of the outside diameter. Larger packages and heavier deniers require the thicker outside stabilization layers to achieve a satisfactory package. EXAMPLES The results reported in these examples are believed to be representative but do not constitute all the runs involving the indicated materials and equipment . For both Examples below, the conditions were: Finish roll diameter: 1.5 inches (ceramic coated) Finish roll rpm: 3-25 rpm Finish roll surface roughness: 600 r s Fiber/roll contact distance: 0.375-0.625 inch Windup speed: 965 ypm (883 mp ) Windup tension: For spandex, due to its very high elongation, this is measured as windup stretch. In the tests below, it was 22.5%. (The amount of stretch may affect both the ability to backwind to the core and the package stability. Too high stretch results in excessive compression and resulting interfiber adhesion, while too little stretch results in poor package stability. This invention improves package stability without compromising backwindability. ) Tension across the finish roll: Enough to maintain the spandex in contact with the roll, about 7% stretch. Package size: 1.1 lb Finish composition: A mixture of 96% silicon oil and 4% magnesium stearate The percent Finish On Yarn is determined by extracting a weighed 100 yard specimen of spandex with tetrachloroethylene (PercleneO which has an infrared absorbance less than 0.50 vs. an air reference in a 0.5 mm cell from a baseline at 1320 cm-1 to the Si-CH3 peak at about 1260 cm-1. A Finish on Yarn Analyzer, Model 8980, equipped with IR Detector Model DT 980 (sold by Duratech, Inc., Waynesboro, VA) is used. The finish content is calculated from the IR absorbance of the Si- CH3 peak and related to % concentration by calibration curves. Average measured finish levels on 100 yard lengths of spandex are expressed as weight percent of fiber. The reference to first, second, etc. describes the yarn as it is removed from the package, so that the "first 100 yards" is the outermost on the package. In order to reduce the finish level on the outside of the spandex package, the finish roll motor is turned off about 1 or 2 minutes before the package is complete, so that at 965 ypm (882 mpm) spinning speed, 965 yards (882 meters) to 2000 yards (1828 meters) of spandex at the outside of the package have reduced finish levels. The finish roll stops rotating instantly, leaving only a thin residual film of finish on its surface; this finish is removed by the passing fibers, which become the outside of the package. Finish may also be applied by other means such as atomizer, spray, or any other method as long as the finish applied is reduced at the outside of the package. Example 1 Fiber: 40 denier PO4G(1800) :MDI:EDA/MPMD 90/10 2.4%NCO; CR-1.7; DEA terminator Additives: 1.5% Cyanox* 1790 2.0% Methacrol* 2138F 0.6% Silicone oil 3.0% ZnO 1.5% BaS04 Measured finish levels, based on weight of fiber: DICK: I'VE ASSUMED THE FOY WAS MEASURED AFTER THE FIRST 100YDS WERE PULLED OFF AND HAVE ADDED 100YDS TO YOUR PREVIOUS TABLE. IS THE 100YD FIGURE RIGHT? 2100 yards (1920 meters) from end: 4.5wt% 700 yards (640 meters) from end: 4.2wt% 400 yards (366 meters) from end: 4.0wt% 150 yards (137 meters) from end: 1.1 wt% Beaming stringup (pull-through) evaluations on a Liba warper (sold by Liba Maschinenfabrik, Naila/Bayern, Germany,) are given below. The creel and warper head model of each run is listed in the table below. Numbers 1, 2, 3 represent packages of the invention, while A, B, and C represent control packages with constant finish levels. Liba Model Man-hours Number of Item Creel Warner Strinσ- ■ up Slouσhsi 1 6F 24E 1.7 21 A 6F 24E >4 >80 2 6E 23E 1.8 18 B 6E 23E 6.0 82 3 6E 24E 2.9 312 C 6E 24E 4.5 84 3 Notes: (1) During creeling and pull through. (2) Shipping and unpacking caused no off-shoulder packages. (3) Shipping and unpacking caused 27 off-shoulder packages. Example II: This fiber is the same except the barium sulfate is omitted. Fiber: 40 denier P04G(1800) :MDI :EDA/MPMD 90/10, 2.4%NCO; CR=1.7; DEA terminator Additives:1.5% Cyanox* 1790, 2.0% Methacrol* 2138F, 0.6% Silicone oil and 3.0% ZnO Finish levels on the outside of the package: Weight % finish on yarn, as a function of distance from the outside end of the yarn, is summarized as follows: Distance (yards) Wt . % finish 0 - 99 1.2 100 - 199 1.7 200 - 299 2.4 300 - 399 2.6 400 - 599 3.2 600 - 1000 4.3 Beaming stringup (pull-through) evaluations on a Liba warper are given below. Numbers 4, 5, and 6 represent packages of the invention, while D represents a control package with constant finish level (4.5wt% based on fiber) . Liba Model Man-hours Number of Item Creel Warper Strinσ- •up Re- -tiesi 4 6F 24E 0.8 0 5 6F 24E 1.7 0 6 6E 23E 0.8 0 D 6F 24E 3.5 4 Notes: Number of knots tied to re-connect spandex broken during pull-through.

Claims: I CLAIM; 1. A spandex supply package having spandex wound up on a cylindrical core and the spandex having a lubricating finish on its surface, characterized in that, for decreased sloughing off of the spandex from the package, at least the last 100 meters of spandex wound up has a decreased amount of finish on the surface, the amount being less than one-haIf the average amount of finish on the surface of the spandex in the supply package. 2. A spandex supply package according to claim 1 wherein no more than the last 500 meters of spandex on the core has the decreased amount of finish on the surface. 3. A spandex supply package according to claim 1 or 2 wherein the weight of finish on the length of spandex having the decreased amount of finish is in the range of 0.2 to 2% based on the total weight of the spandex. 4. A spandex supply package according to claim 1 or 2 wherein the length of spandex having the decreased amount of finish constitutes in the range of 0.1 to 0.5% of the total length of spandex wound up in the package. 5. A process for preparing a spandex supply package, wherein a finish applicator applies a lubricating finish at a predetermined rate to a moving spandex threadline and then the spandex is wound up on a cylindrical core characterized in that the application rate of the finish is decreased to less than half the predetermined rate in the last 100 to 500 meters of spandex being wound on the core. 6. A process according to claim 5 wherein the applicator comprises a rotating finish roll, the rotation of the roll is stopped within 2000 meters of the the last length of spandex to be wound up on the core, and while the roll rotation has stopped, contact is still maintained between the spandex and the application roll.

Inventors: WRAY RHODES EBELING, WRAY, RHODES, EBELING
Applicants: DU PONT, E.I. DU PONT DE NEMOURS AND COMPANY
Application year: 1996
Main classification: B65H75
IPC codes: B65H55, D02H5