US3795096A

US3795096A - Product and process

Info

Publication number: US3795096A
Application number: US00286134A
Authority: US
Inventors: S Dunwoody
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1972-09-05
Filing date: 1972-09-05
Publication date: 1974-03-05
Anticipated expiration: 1991-03-05
Also published as: CA987975A; AR202905A1; FR2198010A1; GB1406749A

Abstract

A slub yarn product is prepared by a process in which a core strand is advanced through a series of false-twisting devices so as to form rotating standing waves ahead of each false-twister and simultaneously feeding yarns to the advancing core at the rotating waves to form a wrapped layer extending all along the core. Slubs are provided by feeding a sliver of discontinuous fibers to the core at a rate which causes the sliver to be intermittently caught in the advancing core and broken into separated portions which become part of the wrapped core. Slubs can also be produced by intermittently advancing the core strand through the wrapping operation to provide a wrapped layer of varying thickness. Slub size and spacing may be random or substantially uniform. The slubs are generally 15 to 35% greater in cross-sectional area than nonslubbed portions, 2 to 5.5 inches long, and spaced 8 to 30 inches between slubs.

Description

Dunwoody, Jr.

[ 1 PRODUCT AND PROCESS Primary ExaminerDonald E. Watkins [75] Inventor: Samuel A. Dunwoody, Jr.,

Martinsville, Va. [57] v ABSTRACT 4 [73] Assignee: E.I. du Pont de Nemours and A slub yarn product is prepared by a process in which Company, Wilmington, Del. a core strand is advanced through a series of falsetwisting devices so as to form rotating standing waves [22] B Sept 1972 ahead of each false-twister and simultaneously feeding [21] Appl. No.: 286,134 4 yarns to the advancing core at the rotating waves to form a wrapped layer extending all along the core. Slubs are provided by feeding a sliver of discontinuous [52] US. Cl. 57/144, 57/160 fibers to the core at a rate which causes the Sliver to g be intermittently caught in the advancing core and I 0 care l g J 156 6 broken into separated portions which become part of 16 the wrapped core. Slubs can also be produced by interrnittently advancing the core strand throughthe [56-] References C'ted wrapping operation to provide a wrapped layer of U T D STATES PATENTS varying thickness. Slub size and spacing may be ranl,9 97,77l 4/1935 McGowan... 57/144 dom or substantially uniform. The slubs are generally 3,332,227 7/1967 Marshall 57/140 J X 15 to 35% greater in cross-sectional'area than non- 3'174371 3/1965 Edwards et a1; 57/140 1 slubbed portions, 2 to 5.5 inches long, and spaced 8 to 3,427,647 2/1969 Field r r r v 57/144 30 inches between Slubs 3,675,409 7/1972 Rosenstcin H 57/144 10 Claims, 5 Drawing Figures ps0 N r PRODUCT AND PROCESS FIELD OF INVENTION This invention relates to wrapped slub yarns ofa type especially suitable for weaving upholstery fabrics, and to a process for making slub yarns.

Field-US. Pat. No. 3,427,647 dated Feb. l 1,1969, discloses a process for preparing a wrapped yarn product by continuously advancing a core strand through one or more false-twisting devices to form a rotating standing wave pattern of multiple balloons in the core strand and freely feeding wrapping yarns to the rotating standing waves to wrap around the core. The nature of the wrapped layer formed about the core can be controlled by the core strand tension, denier, forwarding speed and rotational velocity, as well as the number and denier of the wrapping yarns.

SUMMARY OF THE INVENTION I In accordance with the present invention slub yarns are produced by the improvement in the above process of feeding a sliver of discontinuous fibers to the core strand, at a lower rate than the rate of advancing the core, so that the sliver is intermittently caught in the core and caused to break into portions spaced along the core, and is then wrapped as part of the core to form slubs in the wrapped yarn product. Preferably, a jet device is used to feed the sliver to the advancing core in ajet of air. When a plurality of strands are continuously combined to form the advancing core, the

slub-forming sliver is preferably fed to the core between combining strands. The average slub size and spacing is controlled by the sliver size and rate of feed to the core. The wrapping conditions are preferably controlled to produce a wrapped layer which extends completely along the core with wrapping yarns winding about the core alternately is S and Z twist directions and backwinding about previous windings in tight portions at random intervals along the core.

The slub yarn product of this invention has a fibrous core and a wrapped layer of continuous yarns which extends completely along the core. The roduct is char acterized by slubs which have cross-sectional areas from 15 percent to percent greater than the average cross-sectional area of the nonslubbed portions. The slubs'may be 2 to 5.5 inches long with a distance of 8 to 30 inches between slubs. The product is also characterized by a wrapped layer of wrapping yarns winding about the core alternately in S and Z twist directions and backwinding about previous windings in tight portions at random intervals along the core. The wrapping yarns may be of continuous filaments or spun yarn, or both. The core may be composed of discontinuous tibers in the form of sliver, roving or spun yarn, and may include continuous filaments. Preferably, the core is formed of a plurality of strands of discontinuous fibers and the slubs result from a greater number of core fi bers in slub portions than in nonslubbed portions of the product. In a particularly desirable product, the slubs have random lengths between 2 and 5.5 inches and are randomly spaced at distances of 8 to 30 inches between slubsv For upholstery fabrics, the slubbed yarn product preferably has a core between 5,000 and 9,000 denier in size, of discontinuous fibers, wrapped with continuous-filament yarns to a denier between 6,000 and 10,000 for the slub yarn product.

The slub yarn product may be characterized by a wrapped layer which has a preponderance of wrappings at slub portions of the product. Slubs can be produced by intermittently advancing a core strand through the wrapping operation to provide a wrapped layer of varying thickness.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of a process of this invention.

FIG. 2 is a representation of a section offa wrapped slub yarn product of this invention.

FIG. 3 illustrates a modification of the core-forming operation of FIG. 1.

FIG. 4 illustrates a modification of the wrapping operation of FIG. 1.

FIG. 5 is a representation of a section of slub yarn product having a preponderance of wrappings at the slub portion. t i

DESCRIPTION OF PREFERRED EMBODIMENTS In the process of FIG. 1, all movement of the core 10 through the apparatus is provided by the constant peripheral velocity of driven package 14 resting against smoothing roller 12 Core strands 16, unwound from supply package 18, are led around tension bars 20 into the rotating standing-wave pattern 22 upstream of first torquejet false twister 24. Partially wrapped yarn 30 passes through the longitudinal passage of twister 24 in which it is false-twisted by a vortex of air generated by injecting air tangentially into the passage through pipe 26. A plurality of spaced continuous-filament wrapping yarns 32 from creel 34 issimultaneously fed to the standing-wave pattern 22. Partially wrapped yarn continues through the second rotating standing-wave pattern 36 established by torque-jet false twister 38 just as was'done by twister 24 except that air inlet 40 is reversed to produce an oppositely rotating vortex. A second set of wrapping yarns 42 is simultaneously fed to standing-wave pattern 36'from creel 44. A snubbing guide 46 prevents the twist of twister 38 from influencing the operation of twister 24. Fully wrapped yarn 5O is led around guide 48 to wind-up on package 14 which,

in this embodiment,

velocity. i

The formation of slubs in the process of FIG. I involves discontinuous addition of sliver to the core. Package 56 of sliver 58 is mounted so that the free end of sliver-may be forwarded by driven nip rollers 52 into a forwarding jet of air in jet-device 54. The jetdevice 54 discharges sliver 58 so close to running core 10 that the free'end of sliver 58 must contact and be caught in core 10. The sliver 58 to be employed is a carded, untwisted rope of discontinuous fibrous material which has a low breaking strength. Nip rollers 52 are operated so that the linear velocity of advance of sliver 58 is less than that of core 10. Thus, when the free end of sliverchanges in the wrapped product. The length of each slub is most directly determined by the distance be-' tween the nip rollers 52 and the point of contact of sliver 58 with core 10, and the-length of individual F1} is rotated at constant peripheral bers in the sliver. On the average, breaks occur somewhere near the midpoint of this distance; but any given break can be widely variant from the average. The average spacing of slubs is directly a function of the difference in velocities of forwarding of core and sliver 58. When sliver 58 breaks, a certain amount of time elapses before the free end again travels to contact core 10. In this time, core 10 has advanced a slub-free distance dependent on its higher velocity. The longer any given slub is, the longer is the subsequent section of sliver-free core; and vice versa. Average frequency and length of slubs can be controlled precisely. The scatter of individual values provides an irregularity which is very desirable 'in slub-yarn products.

The above process can be operated so that two or more different slivers 58 are separately led to core 10. The feeding rates may differ so that each sliver produces slubs in the wrapped yarn which differ from the others in average size and/or frequency. Novel effects also result if the slivers differ in color or dyeability. Various other similarly produced effects are immediately apparent, such as the use of wrapping

yarns

32, 42 differing in color or dyeability.

FIG. 2 very schematically represents a portion 70 of the length of a wrapped yarn according to this invention. It is generally round in cross section, though not necessarily perfectlyround. It has lengths 60 of enlar'ged cross section, i.e., slubs, between which are nonslubbed portions 62. Slubs 60 are irregular in length and irregularly spaced apart. Examination of cross sections taken through slubs 60 and those taken through lengths 62 reveals that slubs contain more fiber ends than do lengths 62. When the slub-forming sliver 58 and the continuous core strands 16 are composed or recognizably different fibers, it is readily seen that the slubs 60 are larger solely because they alone contain fibers from sliver 58. Wrapping yarns 64 are shown schematically. They generally are helically wrapped around the core, in telescoped forward and backwound directions. Whether or not they completely hide the core from view depends on how many are used. Also, the more wrapping yams used, the more uniform appears the wrapped layer. Ordinarily, the wrapped slub yarn 50 (FIG. 1) will have numerous small loops of wrapping

yarns

32 or 42 extending radially outward to provide a fuzzy appearance and touch.

FIG. 3 represents a variation of the process of'FIG. l which is particularly suitable when attachment of the free end of slub-forming sliver 58 to core 10 does not occur sufficiently on bare contact. This might be, for instance, when continuous core strands .16 are of straight continuous filaments. In this case, core strands 16 are led into this process in at least two separate groups over separate sets of tension bars 20. They come together at point 66, where first rotating standing-wave pattern 22 begins. Nip-rolls 52 and forwarding jet-device 54 are set up to deliver sliver 58 point 66 and initiation of twisting traps the advancing free end of sliver 58 so that a portion is broken off to initiate a new slub.

When the core strands 16 are slivers, the slivers for the core and theslub-forming sliver 58 can be assembled from supplies of stable fibers, using known assembly devices, and fed directly to the wrapping process in coupled fashion. Since practically any desirable slubsize or slub-frequency can be obtained in practicing this invention, it is not limited to any particularones.

The following example illustrates a specific embodiment of the process and product of this invention.

EXAMPLE 1 A process as depicted in FIG. I is used to make a novel wrapped yarn with slubs irregularly distributed along its length. It is composed of fibrous polyhexamethylene adipamide. Core 10 is formed by leading together four ends of sliver, each end being about 1,500 denier and composed of staple with a maximum length 5Y2 inches (5.08 cm.). Sliib forrning sliver 5 8 is a single end of the kind of sliver used in core'10. The 40-denier wrapping yarns employed are each composed of 13 continuous filaments. Ten wrapping'yarns 32 and ten wrapping yarns 42 are employed, each group being fed to a 3- to 4-inch (7.6 to 10.2 cm.) length of core 10 upstream of its respective torque-jet twister. Center-tocenter spacing of the torque-jet twisters is 14.5 inches (36.8 cm.). I

Each torque-jet twister has an axial torque chamber (yarn passage) which is 0.625 inch (1.59 cm.) in diameter and 0.375 inch (0.95 cm.) long. Pressurized air is fed tangentially to the torque chamber at its lengthwise device 54 is simply a tube along which air flows to carry sliver 58 away from'rolls 52 and to direct its free end into contact with core 10. Air at a pressure of 5 psig. (0.35 kg./cm. gage) is injected into jet-device 54.

The wrapped yarn so produced is characterized as follows: (1) its denier is approximately 7,000; (2) its slubs have cross-sectional areas about 20% greater than the nonslubbed cross-sectional areas; the average spacing between slubs is about 19 inches (48.3 cm.) with a minimum of about 8 inches (20.3 cm.) and a maximum of about 30 inches (76.2 cm.); and the average length of each slub is about 3.5 inches (8.9 cm.) with a minimum of about 2.0 inches (5.1 cm.) and a maximum of about 5.5 inches (14.0 cm.). I

DESCRIPTION OF AN ADDITIONAL EMBODIMENT In the process of FIG. 4, all movemenet of core 10 through the apparatus is provided by rotation of roll 51 against its nip-roll 53. As indicated, roll 51 is driven by a device which may either manually or automatically be turned on and off for preselected intervals of time, either constant or variable. Numerous methods may be used for winding the wrapped product 50. One conve nient one, as shown, winds yarn 50 on sleeve 55 rotated by air motor 57. Motor 57 can be operated continu ously at such a setting that it rotates sleeve 55 only when roll 51 is rotated, thus always taking up the slack. Preferably yarn 50 goes through fixed guide 59 and then through traverse guide 61, the latter reciprocating laterally during rotation of sleeve 55.

Core yarns l6, unwound from supply package 18, are led around tension bars 20 into the rotating standing wave pattern 22 upstream of first torque-jet false twister 24. Partially wrapped yarn 30 passes through the longitudinal passage of twister 24 in which it is false-twisted by a vortex of air generated by injecting air tangentially into the passage via pipe 26. A plurality of spaced continuous-filament wrapping yarns 32 from creel 34 is led freely to the standing-wave pattern 22. Partially wrapped yarn 30 continues through the second rotating standing-wave pattern 36 established by torque-jet false twister 38 just as is done by twister 24 except that air inlet 40 is reversed to produce an oppositely rotating vortex. A second set of wrapping yarns 42 is freely led to standing wave pattern 36 from creel 44. A snubbing guide 46 prevents twist of twister 38 from influencing the operation of twister 24.

This process is used to produce slub yarn products of the type indicated in FIG. 5. Lines 64 represent the reversing helical wrappings of

yarns

32 and 42 formed as core is moving. If only a few wrapping yarns 3 2, 42 are used, core 10 will not appear uniformly wrapped and will be visible in spots. The more wrapping yarns supplied, the more uniform and opaque becomes the wrapping. When core 10 stops, however, each wrapping

yarn

32 or 42 winds about core 10 in a plane substantially perpendicular to the yarn axis, thus forming tight rings 63 around the yarn. It is not necessary that

yarns

32 and 42 be guided from their

creels

34 and 44. Usually, however, there will be at least one guide for each not far removed from the respective

standingwave patterns

22 and 36. Thus, yarns 32 and 42are reasonably constantly spaced from one another to form fairly uniformly spaced rings 63. Depending on spacing I selected, the latter may or may not touch or overlap. When wrapping occurs in two (or more) consecutive standing-

wave patterns

22, 36,'it is easy to adjust the distance between stopping of roll 51 so that the second set of rings 63 is superposed on a previously formed EXAMPLE 2 A novel bulky yarn is made using the process of FIG. 4. It is totally composed of fibrous polyhexamethylene adipamide. Four ends of sliver, each of which is about 1500 denier and consists of staple fibers of up to 2 inches (5.08 cm.) in length, are combined to form the core. Twenty wrapping yarns are used, each of which is a 40-denier yarn of 13 continuous filaments. Ten wrapping yarns 32 are guided to core 10 along a distance of from 3 to 4 inches (7.64 to 10.16 cm.) of corelength, and 10 wrapping yarns 42 are subsequently guided to the core along 3 to 4 inches of core'length as illustrated.

Each of

torque jets

24, 38 has a longitudinal torque chamber which is 0.625 inch (1.58 cm.) in diameter and 0.375 inch (0.95 cm.) inaxial length. Feeding tangentially to the torque chamber at itslengthwise midpoint is an orifice 0.156 inch'(0.397 cm.) indiameter into which pressurized air is injectedA ir pressure for torque jet 24 is 45 psig. (3.16 kg./cm gage); for torque jet 38 it is 60 psig. (4.22 kg./cm. gage) and is injected to produce counterrotation.

Center-to-center separation of the torque jets is 14.5 I

inches (36.8 cm.), and center-to-center separation of wrapping lengths upstream of each torque jet is about 13 inches (33.0 cm.). Rate of core advancement is about yd./min. (137.2 m./mi-n.); thelength of each advancement is 19 to 20 inches (48-51 cm); and the time the core is completely stopped between advancements is about 3 seconds. Each slub is from 3 to 4 inches (7.62 to 10.16 cm.) long, has a cross-sectional area about 30% greater than that of nonslubbed portions, and has numerous fuzzy loops of wrapping yarn extending from its surface. In contrast to the helicaltype wrappings apparent on the surface between slubs, the lay of wrappings in the slubs is essentially perpendicular to the core-axis.

I claim:

1. A slub yarn product comprising a fibrous core and a wrapped layer of continuous yarns which extends completely along the core with wrapping yarns winding about the core alternately in S and Z twist directions and backwinding about previous windings in tight portions at random intervals along. the core, the yarn product being characterized by slubs which have crosssectional areas from 15 percent to 35 percent greater than the average cross-sectional area of the nonslubbed portions.

2 A slub yarn product as defined in claim 1 wherein the wrapped layer comprises a plurality of continuousfilament yarns. v

3. A slub yarn product as defined in claim 1 wherein the fibrous core comprises a. plurality of strands of discontinuous fibers.

4. A slub yarn product as defined in claim 1 wherein the slubs result from a greater number of core fibers in slub portions than in nonslubbed portions of the product.

5. A slub yarn product as defined in claim 1 wherein, the wrapped layer has a preponderance of wrappings at slub portions of the product.

6. A slub yarn product as defined in claim 1 wherein the slubs have random lengths between 2 and 5.5 inches and are randomly spaced at distances of 8 to 30 inches between slubs.

7. A slub yarn product as defined in claim 6 wherein the fibrous core is composed of discontinuous fibers and is between 5,000 and 9,000 denier in size, the wrapped layer is composed of continuousfilament yarns, and the denier of the yarn product is between 6,000 and 10,000.

8. Ina process for preparing a wrapped yarn product by continuously advancing a core strand through a series of false-twisting devices to form rotating standing waves and simultaneously feeding wrapping yarns to the rotating standing waves, the improvement whichcomprises feeding a sliver of discontinuous fibers at a lower speed than the advancing core strand so that sliver is intermittently caught in the core, and caused to break into portions spaced along the core, and is then wrapped as part of the core to form a slub yarn product.

9. A process as defined in claim 8 wherein said sliver is fed to the advancing core strand in a jet of air.

10. A process as defined in claim 8 wherein a plurality of strands are continuously combined to form the advancing core and said sliver is fed to the core between combining strands.

Claims

1. A slub yarn product comprising a fibrous core and a wrapped layer of continuous yarns which extends completely along the core with wrapping yarns winding about the core alternately in S and Z twist directions and backwinding about previous windings in tight portions at random intervals along the core, the yarn product being characterized by slubs which have cross-sectional areas from 15 percent to 35 percent greateR than the average crosssectional area of the nonslubbed portions.

2. A slub yarn product as defined in claim 1 wherein the wrapped layer comprises a plurality of continuous-filament yarns.

3. A slub yarn product as defined in claim 1 wherein the fibrous core comprises a plurality of strands of discontinuous fibers.

5. A slub yarn product as defined in claim 1 wherein the wrapped layer has a preponderance of wrappings at slub portions of the product.

7. A slub yarn product as defined in claim 6 wherein the fibrous core is composed of discontinuous fibers and is between 5,000 and 9,000 denier in size, the wrapped layer is composed of continuous-filament yarns, and the denier of the yarn product is between 6,000 and 10,000.

8. In a process for preparing a wrapped yarn product by continuously advancing a core strand through a series of false-twisting devices to form rotating standing waves and simultaneously feeding wrapping yarns to the rotating standing waves, the improvement which comprises feeding a sliver of discontinuous fibers at a lower speed than the advancing core strand so that sliver is intermittently caught in the core, and caused to break into portions spaced along the core, and is then wrapped as part of the core to form a slub yarn product.