US3280546A - Nubbed yarn and process for making same - Google Patents

Description

R. F. SPICER ETAL 3,280,546

NUBBED YARN AND PROCESS FOR MAKING SAME 1 Oct. 25, 1966 2 Sheets-Sheet 1 Filed June 12, 1964 Oct. 25, 1966 sp c ETAL 3,280,546

NUBBED YARN AND PROCESS FOR MAKING SAME Filed June 12, 1964 2 Sheets-Sheet 2 United States Patent M 3,280,546 NIJBBED YARN AND PROCESS FOR MAKING SAME Ronald F Spicer and Preston F. Marshall, Walpole,

Mass, 'assignors to The Kendall Company, Boston,

Mass, a corporation of Massachusetts Filed June 12, 1964, Ser. No. 374,743 6 Claims. (Cl. 57-144) This invention relates to novelty yarn of the nub type.

More particularly it relates to a nubbed yarn in which the nubs are formed by an interlocking engagement between a core strand and a wrapping strand, so that the nubs cannot be displaced or caused to slide along the core strand.

In the preparation of textured fabrics for the garment, upholstery, drapery, and similar trades, extensive use is made of novelty yarns which, by various manipulations in a twisting process, are caused to take on an alternating thick-and-thin appearance. Such yarns generally involve the manipulation of at least two strands. When one strand is wrapped about another rather tightly for a multiplicity of turns, and this wrapping is carried on at spaced intervals, a so-called knop yarn is formed. A boucl yarn is formed by looping a wrapping strand loosely around a core strand, and holding the loops in place by a third or hinder strand. Slub and nub yarns are likewise characterized by deliberately-induced thick and thin places, slubs generally being of a soft nature and possessing tapered leading and trailing edges.

A nub in a yarn is generally a more abrupt discontinuity than the other types, and appears as a mass or ball of fibers or filaments scattered along the length of the yarn like popcorn threaded on a string. Due to their generally similar natures, it is not always possible to draw a strict differentiation between slubs and nubs.

In US. Patent 3,041,812, to one of the present inventors, there is described a method of making a novelty yarn, therein called a slub yarn, by the following steps:

(1) Continuously passing a straight tensioned continuous core strand axially through a cylindrical body of fluid whirling about a central axis.

(2) Continuously overfeeding a wrapping strand into said body of fluid, generally tangentially thereof.

(3) Forming doubled-back loops of said wrapping strand around the circumference of said core strand in an intermittent thick-and-thin manner.

(4) Withdrawing the composite yarn from the whirling body of fluid.

Such yarns, though useful for many textile applications, suffer from at least one drawback. The core strand, about which the wrapping strand is disposed, is maintained under tension during the wrapping process. The final wrap, or nub, therefore, is disposed about a generally straight, smooth, unconvoluted core strand. In the exigencies of weaving and knitting, where the heddle eyes, reeds, or knitting needles exert a frictional dragon the yarn, yarns of this type may show a tendency for the nubbed wrappings to slip or slide along the smooth core, bunching together and destroying the evenly-spaced nub effect which is generally desirable in fabrics made from such yarns.

We have found that if the core strand is fed to the body of fluid not under tension but under a controlled degree of overfeed or slack, the core strand, during the wrapping operation, is twisted into a series of spaced-apart bifilar pedicled loops. The wrapping strand protrudes in its own loop-like configuration from the core strand loops, and the resulting entanglement or engagement between wrapping strand and core strand is such as to resist substantially any attempt to slide or displace the resulting nub along the axis of the composite yarn.

3,28%,545 Patented Oct. 25, 1966 It is therefore an object of this invention to provide a nubbed yarn of unique configuration. It is also an object of this invention to provide a nubbed yarn comprising at least two strands, both strands having at intervals a looped configuration. It is a further object of this invention to provide a nubbed yarn wherein the nubs are securely fixed in non-slipping relationship to a core strand. Other objects of the invention will appear more fully from the following description thereof.

The invention will be better understood in connection with the drawings, in which:

FIGURE 1 represents a side elevation of a nubbed yarn of this invention.

FIGURES 2 through 6 represent the initial stages in the formation of the yarn of this invention, showing by stages the formation of convolutions in the core strand while it is being wrapped by the wrapping strand.

FIGURES 7 through 9 represent further stages in the development of pedicled loops in the core strand, the wrapping strand being omitted for clarity.

FIGURE 10 represents the interengagement of wrapping strand and core strand at the base of the pedicled loop of the latter, the wrapping strand engagement with the core strand in the rest of the loop again being omitted for clarity.

FIGURE 11 is a representation of a cross section taken along the yarn axis through one of the nubs of FIG- URE 1.

FIGURE 12 is a cross-sectional side view of a vortex tube suitable for producing the yarn of this invention.

FIGURE 13 is a cross-sectional end view of the tube of FIGURE 12.

FIGURE 14 represents schematically a preferred embodiment of the process of the invention.

GENERAL NATURE OF THE PROCESS Referring to FIGURE 14, the core strand 10 is supplied from a package 21, threaded over star wheels 22 and 24, and delivered to the vortex chamber 26 wherein it becomes textured as explained more fully hereinbelow. Simultaneously one or more wrapping strands, 12, are delivered from a supply package 34, around the feed wheel 32, to the vortex chamber through the wrapping strand inlet 29. The composite nubbed yarn 36 is drawn from the vortex tube, which is equipped with a tangentially-directed air stream through the inlet 28, and passes around star wheels 38 and 40 to guide roll 42 and Winder 44.

ACTION OF THE VORTEX CELL If the apparatus as set forth above is operated with the core strand under tension, the result is a wrapped yarn as described in US. Patents 3,076,307 and 3,041,812, to one of the present inventors. We have found, however, that a novel and desirable result is brought about if the core strand tension is decreased sufiioiently to allow this strand to be influenced by the high twisting energy of the whirling fluid mass contained within the vortex cell. The probable sequence of events is shown in FIGURES 2 through 9.

FIGURE 2 represents an initial stage in the development of a typical yarn of this invention, wherein the wrapping strand 12, being whirled around the core strand 10, is doubled thereabout in a bifilar configuration headed by a loop 13. Due to the slack in the core strand tension, at hump or bend is formed in this strand, as shown at 11. The core strand rotates around the tube axis with a cranking motion at the same time as the highly overfed wrapping strand is wrapped around the core strand, as shown in FIGURE 3, where the bend in the core strand has been accentuated, leading to the formation of a core strand loop as shown in'F-IGURE 4. The force of the whirling fluid has by this time created many bifilar loops of wrapping strand 12 to engage with the loop 11 of the core strand, some of these wrappingstrand loops passing through other wrapping strand loops as at 15, and some being twisted along their length, as shown at 17 in FIGURE 4.

The continued twisting and cranking motion imparted to the core strand then causes the bend or loop 11 to twist into a crunodal loop, as shown in FIGURE 5, said loop continuing to be twisted into a pedicled bifilar loop as shown in FIGURE 6. The open portion of this loop is filled with bifilar wrapped loops of wrapping stran disposed about the core strand.

When operations are carried out in a chamber about Mr inch in diameter and at an air pressure of 100 p.s.i.g., the characteristic loop formed in the core strand goes through the stages shown in FIGURES 7 and 8, developing numerous strand crossings along its pedicled stem. As the core strand loop is twisted more tightly, it tendst-o collapse into a tight ball as shown in FIGURE 9. In FIGURES 7, 8, and 9, the Wrapping strand has been omitted for clarity.

FIGURE 10 represents a typical action of the loops of wrapping strand at the base of the twisted loop of core strand, where the protruding loops of the Wrapping strand 12 are Whipped around the base of the core strand loop in an interlocking interengagement. To some extent a similar effect is found also in the body of the nub: that is, as the yarn composite of FIGURE 4, for example, progresses to the tightly-twisted core configuration of FIGURE 9, the longer loops 15, and 17 of FIGURE 4 not only weave in and out of the twists that are developed in the core strand, but they are wrapped around the collapsing and tighting core strand loop configuration.

NATURE OF THE NUBBED YARN The nature of the final product of this invention is shown in FIGURE '1, wherein the core strand 10 is gathered into a tightly twisted l-oop configuration (reflecting the stage shown in FIGURE 9), with the Wrapping strand 12 disposed in regular wrapping configuration between nubs, but within the nub being falsely wrapped around the core strand in loose doubled loops, and blossoming out into a voluminous burst of yarn expanded into three dimensions. In the nub structure, the multiplicity of radially-extending loops of wrapping strand tend to more or less completely obscure the knot-like convolution of the core strand shown in FIGURE 9, said convolution of the core strand generally being composed of a shorter length of strand than the length of wrapping strand present in the nub, and also generally being more tightly twisted.

In producing nubbed yarns of this type, a vortex cell of the type described in US. Patent 3,082,591, of March 26, 1963, may be used. More consistently uniform results are realized, however, if the modification shown in the present FIGURES 12 and 13 is employed. In FIG- URE 12, the main body of the cell 50 is formed from a section of quartz or glass tubing, conveniently inch long with /2 inch outside diameter and 0.273 inch inside diameter. The open ends of the tube 50 are partially filled by a piece of glass tubing 62 defining the core strand inlet 52, ,set in a rubber gasket '56, and on the outlet end by a piece of ceramic, brass, or glass tubing 60, defining the nubbed yarn outlet 54, and set in a rubber gasket58. A convenient size for the entry tube 62 is 0.152 inch outside diameter, 0.089 inch inside diameter, and for the exit tube 60, 0.187 inch outside diameter and 0.147 inch inside diameter. These dimensions are illustrative, not restrictive, and may be varied, cells up to several inches in diameter having been constructed in accordance with this invention to operate on coarse cords or ultra-heavy strands.

The air inlet opening and the wrapping strand inlet opening are shown as dotted- lines 28 and 29 at FIGURES distances to which the inlet tube 62 and the exit tube 60 project into thecentral chamber of the vortex tube, and are adjustable, as set forth below.

A wide variety of nubbed yarn products can be made, Within the scope of this invention, by manipulating the variables in the process. Among the variables which have been found to influence the thickness or size and the spacingof the nubs along the composite strand are l the following:

(1) The overall rate of production of the composite yarn.

(2) The rate of overfeed of the core strand.

(3) The rate of overfeed of the wrapping strand.

(4) The total denier and denier per filament of the core strand and the wrapping strand.

(5) The air pressure.

(6) The vortex tube dimensions and settings.

By proper choice of variables, composite nubbed yarns can be made in which the size of the nubs varies from about ,5 inch to A inch or more, size being measured by the diameter of the nub in an uncompressed state. The spacing between nubs can be varied from an average of about /2 inch to an average of about 2 inches or more, the exact spacing being randomized around these averages. These general figures all relate to a small vortex cell-- that is, a cylindrical chamber of about 4 inch diameter and inch high. Large cells give nubs which are coarser and differently spaced, depending on the air pressure and on themoduli of the strands employed.

The following examples will illustrate various embodiments of the process and product of the invention. In Examples 14, the following factors were held constant:

(1) The core strand was denier 68 filament nylon with /2 turn of Z-twist.

(2) The wrapping strand feed rate was 2,534 feet per minute.

(3) The air pressure was 90 pounds per square inch.

(4) The vortex tube dimensions were those set forth above as representative, with the inlet tube 62 projecting inch into the chamber (distance A of FIGURE 12) and the outlet tube 60 projecting inch into the chamber (distance B of FIGURE 12).

Example 1 Wrapping strand: 55 denier 15 filament dull acetate, with 2 turns of Z-twist.

Wrapping strand overfeed: 1250% Composite yarn take-up speed: 187 feet per minute.

Core strand feed rate: 306 feet per minute.

Core strand overfeed: 63%

Calculated denier of product: 972

Measured denier: 970

Size of nubs: about A inch in diameter.

Nub spacing: Ma inch to 1% inches apart.

Example 2 Example 3 Wrapping strand: denier 40 filament. dull acetate with 2 turns of Z-twist. Wrapping strand overfeed:.-19307 Composite yarn take-up speed: 125 feet per minute.

Core strand feet rate: 485 feet per minute.

Core strand overfeed: 288% Calculated denier of product: 3588 Measured denier: 3123 5 Size of nubs: about A inch in diameter.

Nub spacing: /2 inch to 1 inch apart.

Example 4 Wrapping strand: 75 denier filament dull acetate with 2 turns of Z-twist.

Wrapping strand overfeed: 1250% Composite yarn take-up speed: 187 feet per minute.

Core strand feed rate: 548 feet per minute.

Core strand overfeed: 192% Calculated denier of product: 1422 Measured denier: 1334 Size of nubs: about inch in diameter.

Nub spacing: 1% inches to 2% inches apart.

Comparing Examples 1 and 2, it is seen that increasing the denier of the wrapping strand from 55 to 75, with other factors constant, caused the size of the nubs to double. In a comparison of Examples 2 and 4, it is seen that the same wrapping strand and wrapping strand overfeed rate were used. The high rate of core strand overfeed of Example 4, however (192% versus 63% of Example 2), meant that the core strand constituted over 28% of the calculated denier of the final product, whereas in Example 2 the core strand constituted only 18% of the calculated denier of the final product. It is characteristic of the process of this invention that yarns can be produced which are superficially similar, but in which the apparently similar nubs contain varying ratios of core strand content to wrapping strand content.

It is also characteristic of products made according to this invention that although the spacing of the nubs can be varied, as seen from the examples, the nubs are not precisely spaced equidistant from each other under any given set of conditions. The average spacing between our spaced-apart nubs can be controlled, but individual spacing will vary around the average. Since nubbed yarns are frequently employed to make fabrics which are highly textured in a randomized fashion, our yarns are eminently suited for such purposes.

The process of this invention is not limited to the use of conventional textile yarns in either the core strand or the wrapping strand. Glass strands, stretch strands (of the multifilament bulked or crimped type) and elastomeric strands such as rubber or spandex may be employed, as illustrated by the following examples. 0

Example 5 Using the same vortex cell and air pressure as in Examples 1 through 4, the following all-glass nubbed yarn was made:

Example 6 Again using the same vortex cell and air pressure as in Examples 1 through 4, a stretch-core nubbed yarn was made as follows:

Core strand: denier 17 filament 2 ply, 7 turns of S- twist, Superloft stretch nylon yarn, a product of Leesona Corporation.

Wrapping strand: 75 denier 20 filament dull acetate with 2 turns of Z-twist.

Wrapping strand overfeed: 1250% Core strand feed rate: 306 feet per minute.

Composite yarn take-up speed: 187 feet per minute.

Core strand overfeed: 63%

Calculated denier of product: 1242 Measured denier: 1180 Nub size: about /8 inch in diameter.

Nub spacing: 1 inch to 1% inches apart.

This yarn is substantially inelastic as produced, and can be handled as any other inelastic yarn through a weaving or knitting process. By using dry heat, or steaming, or hot water, etc., in finishing the fabric, the above yarns can be shrunk, with the development of an elastic extensibility. The yarn of Example 6, after steaming, had an elongation of In preparing nubbed yarns of this invention using an elastomeric core such as rubber or spandex, the ease of elongation of the core strand presents certain problems.

First, it is diflicult to measure the rate of overfeed of the input core strand, due to its elasticity. We prefer, therefore, for any given elastomeric core strand, to dissect a convenient measured length of the final product, say 20 inches, measured without tension. The excess of core strand over 20 inches, again measured relaxed, divided by 20, is expressed as core strand overfeed. This overfeed will generally be between 5% and 50%, and the excess elastomeric core strand will be found in a spaced-apart series of nubs in which the core strand has been twisted on itself as in FIGURES 8, 9 and 10.

Example 7 With the same conditions as in the previous examples, the following nubbed yarn was made:

Core strand: 280 denier spandex.

Wrapping strand: 75 denier 20 filament dull acetate, with 2 turns of Z-twist.

Wrapping strand overfeed: 1250% average.

Composite yarn take-up: 224 feet per minute.

Measured denier, relaxed: 950

Nub size: to 05 inch, variable.

Nub spacing: 2 inches to 10 inches apart.

When the acetate wrapping strand was dissolved from a 20-inch length of relaxed composite strand by means of acetone, a 24-inch length of relaxed core strand was recovered, indicating an average core overfeed rate of 20%.

Although the above examples have illustrated the use only of continuous filament strands, we have found the invention to apply equally well to regular commercial yarns of spun staple fiber. Such spun yarns may be used as the core strand, as the wrapping strand, or both. Plied yarns may be used as either or both core and wrapping strand, as well.

In general we prefer to employ an overfeed of between 15% and 200% on the core strand, depending on the size and spacing of nubs desired. When nubs are cut from the composite yarn and untangled, it is found that from /2 inch to 5 inches of core strand, and from 4 inches to 20 inches of wrapping strand, have been gathered into each nub, within preferred processing ranges. It should be appreciated that although the wrapping strand and core strand are here spoken of independently, the wrapping strand is actually disposed around the core strand in the form of doubled loops while the core strand is simultaneously being formed into loops, as shown in FIGURES 4 through 10 and as explained above. This leads to a unique type of nub formation, characterized by a blossoming effect and a resistance to slippage of the nubs along the axis of the composite yarn.

It has been proposed previously to create nubbed or slubbed yarns by feeding two yarns into a zone of fluid turbulence, as evidenced by US. Patent 3,118,269 to 7 Bilsky, and U.S. Patents 2,997,837 and 3,043,087 to Breen. In addition, fluid turbulence has been used to blow the filament-s of one strand through the separated filaments of a second strand, in a pulsating operation to give a composite yarn in which one strand is randomly interlaced through the body of another. However, the structure and properties of such yarns resemble the structure and properties of the yarns of this invention only superficially.

Having thus described our invention, we claim: 1. A nubbed yarn comprising at least one core strand and at least one wrapping strand,

said wrapping strand being intimately associated with said core strand in the form of doubled-back bifilar loops wound for a multiplicity of turns around said core strand and possessing no net true twist about said core strand, the wrapped core strand being at spaced-apart intervals twisted into pedicled loops, the core strand constituting said pedicled loops being associated, within said pedicled loops, in entangled relationship with said 'bifilar loops of wrapping strand, said pedicled loops of core strand, together with the wrapping strand associated therewith within said pedicled loops constituting a series of nubs spaced along the length of the composite yarn, said nubs being characterized by substantial resistance to displacement along the length of said yarn.

2. The product according to claim 1 wherein said 30 core strand is a spun yarn.

3. The product according to claim 1 wherein both said core strand and said wrapping strand are spun yarns.

4. The product according to claim 1 wherein the core strand is a multifilament stretch yarn of synthetic polymeric material.

5. The product according to claim 1 wherein the core strand is an elastomeric strand.

6. A process for producing a wrapped nubbed yarn which comprises continuously overfeedi'ng a core strand into a vortex cell containing a whirling mass of fluid, in a direction normal to said whirling mass,

continuously overfeeding at least one wrapping strand I References Cited by the Examiner UNITED STATES PATENTS 7/ 1962 Marshall 576 2/1963 Marshall 57152 3/1963 Marshall 576 FRANK J. COHEN, Primary Examiner.

J. PETRAKES, Assistant Examiner.

Claims (2)

1. A NUBBED YARN COMPRISING AT LEAST ONE CORE STRAND AND AT LEAST ONE WRAPPING STRAND, SAID WRAPPING STRAND BEING INTIMATELY ASSOCIATED WITH SAID CORE STRAND AND POSSESING NO NET TRUE TWIST ABOUT LOOPS WOUND FOR A MULTIPLICITY OF TURN AROUND SAID CORE STRAND AND POSSESSING NO NET TRUE TWIST ABOUT SAID CORE STRAND, THE WRAPPED CORE STRAND BEING AT SPACED-APART INTERVALS TWISTED INTO PEDICLED LOOPS, THE CORE STRAND CONSTITUTING SAID PEDICLE LOOPS BEING ASSOCIATED WITHIN SAID PEDICLED LOOPS , IN ENTANGLED RELATIONSHIP WITH SAID BIFILAR LOOPS OF WRAPPING STRAND, SAID PEDICLED LOOPS OF CORE STRAND, TOGETHER WITH THE WRAPPING STRAND ASSOCIATED THEREWITH WITHIN SAID PEDICLED LOOPS CONSTITUTING A SERIES OF NUBS SPACED ALONG THE LENGTH OF THE COMPOSITE YARN, SAID NUBS BEING CHARACTERIZED BY SUBSTANTIAL RESISTANCE TO DISPLACEMENT ALONG THE LENGTH OF SAID YARN.

6. A PROCESS FOR PRODUCING A WRAPPED NUBBED YARN WHICH COMPRISES CONTINUOUSLY OVERFEEDING A CORE STRAND INTO A VORTEX CELL CONTAINING A WHIRLING MASS OF FLUID, IN A DIRECTION NORMAL TO SAID WHIRLING MASS, CONTINUOUSLY OVERFEEDING AT LEAST ONE WRAPPING STRAND TO SAID VORTEX CELL IN A DIRECTION TANGENTIAL TO SAID WHIRLING MASS OF FLUID, CONTINUOUSLY WRAPPING SAID WRAPPING STRAND IN THE FORM OF DOUBLE-BACK LOOPS AROUND SAID CORE STRAND, CONTINUOUSLY TWISTING THE THUS-WRAPPED OVERFED CORE STRAND INTO A SPACED-APART SERIES OF TWISTED LOOPS, AND CONTINUOUSLY REMOVING SAID WRAPPED NUBBED YARN FROM SAID CELL.

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