US2454854A - Drying wound packages - Google Patents

Description

' but imperforate cover or wrapper Patented Nov. 30, 1

DRYING WOUND PACKAGES swortlunore, lPa.. assignor Graeme G. Whyflaw,

to American Viscose Corporation,

Wilmington,

Deb, a corporation of Delaware No Drawing. Application October 3, i944,

Serial No. 557,082 Claims. (ill. 8d7) r l This invention relates to a method of dryin filamentary material in the form of wound packages, and it is applicable particularly to those packages which lack a rigid internal support, such as rayoncakes formed within spinning buckets whether or not provided with the conventional protective cover of knitted fabric. I

It has heretofore been suggested to apply an air and liquid-tight covering, such as an elastic sleeve or tube of rubber, about the outer and end surfaces of the windings or packages and then drying so that the drying proceeds progressively from the inside windings to the outside windings. In this manner, all of the windings are free to shrink, and by the time the outermost windings undergo drying, the-inner windings havealready shrunk so they do not restrain shrinkage oi the outer windings, as would be the case it no cover ing were present. The previous practice oi wrapping a cake with a wrapper entirely impervious to moisture during the whole course of drying has been found undesirable in that the entrapped moisture builds up an outer zone of high humidity. and high temperature within the cake, causing dehydration of the filamentary material inthe outer windings adjacent the wrapper with subsequent dyeing effects. It is the object oi this invention to provide a wrapper which greatly retards the flow of moisture outwardly from the ,cake, thereby preventing undue case=hardening,

but at the same time allows sufilcient moisture to pass through the wrapper to prevent excessive building up of temperature and humidity within any portion of the cake.

In accordance with the present invention it has been found that dried I ing, shrinkage and tactile characteristics can be obtained with considerably shortened drying time and with negligible degradation by providing the packages to be dried with a moisture-absorbent comprising a sheet of cellulosic material exhibiting shrinkage 1 on drying approximately corresponding to that of the filamentary material. In th e specifications is intended to refer definite interstitial and claims, the word sheet to structures that lack any openings etxending clear through the thickness thereof, and accordingly it excludes any such foi'aminous article as ordinary cloth.

Examples ofl'materials of which covers for application to viscose rayon cakes may be made are thin sheets of paper or regenerated cellulose, such as in the form of Cellophane. Paper-like artificial "ieltsf comprising a mixture of cellulosic fibers and thermoplastic binder fibers, such as of vinyl resins, in which one or. both types may be of paper-making or textile-makinglength, are.

- useful. Papers of the high-wet strength type are yarns having uniform dyes valuable provided they are moderately moistureabsorbent. In the claims, the term "paper is intended to include these thin, paper-like artificial felts?" The cover is preferably in the form of a sleeve or tube longer than the cake and has a diameter somewhat larger than the outer diameter of the cake in the condition of application. The cover may be applied wet or dry. In general, applica tion in the dry condition is preferred, b t resenerated cellulose sleeves which have never been dried, but which are stored in moist condition such as in a vessel 01 Water, may be applied wet with great advantage.

The covers used shrink to substantially the same extent as the cakes during drying. Commercially available papers having the appropriate shrinkage characteristic may be made originally in the form of a tube, or a flat sheet of appropriate size and shape may be formed into a tube, the overlapped ends being joined by a suitable waterproof adhesive.

In the case of the thin artificial felts mentioned above comprising thermoplastic binder fibers, the shrinkage may be partially or completely accomplished by virtue of the shrinkage tendencies of the binder fibers under the action of the heat used in drying. For this purpose, stretched fibers of vinyl chloride-acetate copolymer having a shrinkage temperature slightly below the temperature of the drying medium may be selected for making the artificial felt.

Cellophane tubes may be made by a process involving stretching during the drying, so that when placed about the rayon cakes they are free I to shrink during drying of the wrapped cake.

possible with the wrappers heretofore used without encountering non-uniformity of shrinkage, dyeing, and other characteristics which normally result from case-hardening.

By using a moisture-absorbent wrapper which wrapper can EdSOI'b 3 A shrinks during drying, a small proportion of the moisture gradually passes through the wrapper and is slowly vaporized at its external surface. such vaporization causes the wrapper to shrink into firm contact with the windings, so that the liquid in the cake and maintain itself in a partially dried condition throughout the period required for the main drying to progress from the inside to the outer windings of the cake. Thus, partial dehydration of the outer-windings occurs and prevents the development of an outer zone of high temperaturemigh humidity conditions while rapid and complete dehydration progresses from the inner windingsto the outer partially dried windings. Thedrying is thus effected without encountering the stew-' ing of the outer windings which would hydrolyze the cellulose thereof. V

The use of cellulosic material in the wrapper is advantageous in that the equilibrium set up between the moisture present in the outer windings and the wrapper is such as to assure slow passage of the moisture throhgh the wrapper to maintaifi it in a but partially dried condition at all times until completion so that the wrapper clings tothe'cake but allows surplus moisture to gradually pass therethrough. In addition, the wrapper being made of the same material as the cake of rayon does not remove any finishes, such as soaps, oils, waxes, or the like, from the outer windings by selective absorption, and furthermore is not deleteriously affected by such finishes, as isthe case of rubber wrappers when a mineral oil lubricant is present on the cake. I

It is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim 1. A method of drying a wound filamentary package of annular shape comprising the steps of covering the outer and and surfaces of the package with an imperfcrate moisture-absorbent sheet of non-fibrous material produced from a solution of cellulose and subjecting all surfaces of the wrapped package to a heated drying medium.

2. A method of drying a wound filamentary package of an annular shape lacking a rigid internal support comprising the steps of covering the outer and end surfaces of the package with an-imperforate moisture-absorbent sheet of nonflbrous material produced from a solution of cellulose and subjecting all surfaces of the wrapped 5 package to a heated drying medium.

3. 1b method of drying a wound filamentary package of annular shape comprising the steps of covering the outer and and surfaces of the package with an imperforate moisture-absorbent sheet of non-fibrous material produced from a solution of cellulose exhibiting a shrinkage approximately corresponding to that of the filamentary material and subjectirig all surfaces of the wrapped package to a heated drying medium.

4. 'A method of drying a wound filamentary package of annular shape comprising the steps of covering the outer and end surfaces of the package with an imperforate moisture-absorbent paper tube exhibiting a shrinkage approximately corresponding to that of the filamentary mateof drying of the cake. 25

rial and subjecting all surfaces of the wrapped package to a heated drying medium.

5. A method of drying a" wound filamentary package of annular. shape comprising the steps 5 of covering the outer and end surfaces of the ackage with an. imperforate moisture-absorbent regenerated cellulose tube exhibiting a shrinkage approximately corresponding to that of the filamentary material and subjecting all surfaces the wrapped package to a heated drying me- 6. A methodof drying a wound filamentary package of annular of covering the outer and end surfaces of the 'package with an imperforate moisture-absorbent v Cellophane tube exhibiting a shrinkage approximately corresponding to that of the filamentary material and subjecting all surfaces of the wrapped package to a heated drying medium.

7. A method of drying an annular wound package of rayon comprising the steps of covering the outer and end surfaces of the package with an imperforate moisture-absorbent sheet of nonfibrous material produced from a-solution of cellulose exhibiting a shrinkage approximately corresponding to that of the rayon, and subjecting all surfaces of the wrapped package to a heated drying'medium.

8. A method of drying an annular wound package of rayon comprising the steps of covering the outer and end surfaces of the package with an imperforate moisture-absorbent paper tube.

exhibiting a shrinkage approximately corresponding to that of the rayon, and subjecting all surfaces of the wrapped package to a heated drying medium. a 9. A method of drying an annular wound package of rayon comprising the steps of covering the outer and end surfaces of the package with an imperforate moisture-absorbent regenerated cellulose tube exhibiting a shinkage approximately corresponding to that of the rayon, and subjecting all surfaces of the wrapped package to a heated drying medium. 10. A method of drying an annular wound package of rayon comprising the steps of covering the-outer and end surfaces of the package with an imperforate moisture-absorbent Cellophane tube exhibiting a shrinkage approximately corresponding to that of the rayon, and subjecting all surfaces of the wrapped package to a heated drying medium.

GRAEME G. WHY ILAW.

REFEBENGES CITED UNI'IED STATES PATENTS Number Name Date 1,867,609 Bitter et a1 July 19, 1932 1,917,512 Elssner July 11, 1933 1,919,526 Oppenlaender et al. July 25, 1933 1,999,585 Bruggeman Apr. 30, 1935 55 2,098,620 Fonda Nov. 9, 1937 2,266,375 Mengeringhausen' et al Dec. 16, 1941 FOREIGN PATENTS Number Country Date 365,810 Great Britain Jan. 28, 1932 shape comprising the steps