1. Field of the Invention
This invention relates to a spandex supply package having a cylindrical core on which is wound spandex that has a lubricating finish on its surface. 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 on the rest of the wound-up spandex. As a result of the decreased amount of lubricating finish 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.
2. 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 subsequent 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, or the like, spandex is wound up on a cylindrical core. Equipment for this purpose is well known. For example, U.S. Pat. Nos. 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 thread-lines onto tubular cores to form spandex supply packages. However, during shipping and handling of such supply packages difficulties are sometimes encountered. For example, the spandex sometimes sloughs off the edges of the wound-up packages (i.e., the spandex near the flat circular faces of the wound up package falls off the edges of the package). Also, if the package is held with the cylindrical core in a vertical position during shipment, the spandex sometimes can slough off from the package and fall to the bottom of the shipping container. A similar phenomenon sometimes occurs when the spandex package is removed from the shipping container and the spandex sloughs off onto the floor. The sloughing off of spandex from a supply package creates time-consuming difficulties and waste in subsequent textile operations, such as beaming, warping, knitting, weaving, mechanical covering, air-jet entangling and the like.
Lubricating finishes for spandex and equipment for applying the finish to the spandex are well known. For example, U.S. Pat. No. 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 thread-lines 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 the edges of supply packages.