05/019440

08/24/1971

03/13/1970

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28/259

D02G1/00; D02G1/00

28/1.2,72.1,71.3

Rimrodt, Louis K.

This application is a continuation-in-part of my similarly entitled copending U.S. Pat. application Ser. No. 714,171 filed Mar. 19, 1968, now U.S. Pat. No. 3,500,516, granted Mar. 17, 1970, which was a continuation-in-part of my U.S. Pat. applications Ser. No. 543,947, now U.S. Pat. No. 3,374,514, and Ser. No. 686,424, now U.S. Pat. No. 3,457,613.

1. In apparatus for treating a textile strand drawable to increased length, the improvement comprising drawing means for drawing a textile strand to increased length including at least one roll adapted to receive the strand in essentially nonslipping contact therewith and to rotate at a first speed, and at least one other roll adapted to receive the strand in essentially nonslipping contact therewith and to rotate at a second speed greater than the first and thereby to draw the strand to increased length, one such other roll being maintained at a temperature below the plasticization temperature of the strand, and heating means juxtaposed to but spaced from the surface of that other roll at a location thereon at which the strand is at such increased length and adapted to heat the strand to plasticization temperature on one side while the other side is maintained relatively cool on that roll.

2. Strand-treating apparatus according to claim 1, wherein the heating means includes a hot fluid jet.

3. Strand-treating apparatus according to claim 2, wherein the jet is directed obliquely onto that cool roll.

4. Draw-crimping apparatus for textile strands, comprising a solid surface movable at a given speed for movably supporting a textile strand in essentially nonslipping contact therewith, cooling means for maintaining the supporting solid surface at a temperature sufficiently low to preclude plasticization of the strand while in contact therewith, restraining means for limiting movement of the strand to a slower speed in advance of its contact with the cooled supporting surface so as to draw the strand to increased length therebetween, and heating means juxtaposed to but spaced from the cooled supporting surface for heating the side of the strand opposite thereto to substantially plasticization temperature while the strand is supported thereon.

5. Draw-crimping apparatus according to claim 4, wherein the cooled moving solid-supporting surface is the peripheral surface of a roll rotatable at the given speed.

6. Draw-crimping apparatus according to claim 4, wherein the heating means comprises a fluid jet. 7Draw-crimping apparatus according to claim 4, including means for winding the strand away from the cooled supporting

In addition to edge-crimping, gear-crimping, jet-crimping, stuffer-crimping, and twist-crimping it is known to crimp textile strands of at least partially oriented (molecularly) linear polymeric material by setting up a temperature gradient transversely of the strand, whereupon the strand assumes a helically crimped configuration under low (or no) tension after cooling of the heated side. In the last-mentioned method the heating of the one side of the strand may be accomplished by contact with a hot solid, liquid, or gas; the opposite side is maintained cool by conductive contact with a solid surface at appropriate temperature. Resulting processing and product characteristics leave a good deal to be desired, however.

A primary object of the present invention is improved crimping of textile strands by differential temperature treatment.

Another object is continuous drawing and crimping of textile strands.

Yet another object is improved multiple-end crimping of textile strands.

A further object is provision of apparatus for accomplishing the foregoing objects.

Other objects of this invention, together with means and methods for attaining the various objects, will be apparent from the following description and the accompanying diagrams.

FIG. 1 is a side elevation, partially schematic, of apparatus according to the present invention; and

FIG. 2 is a side elevation, on an enlarged scale and partly cut away and in section, of a detailed portion of FIG. 1;

FIG. 3 is a front elevation of a roll component of the preceding views; and

FIG. 4 is an oblique sectional view taken at IV--IV on FIG. 2.

FIG. 5 is a partially schematic side elevation of apparatus of this invention similar to the apparatus of FIG. 1 but especially adapted to treating a multiplicity of strand ends alongside one another;

FIG. 6 is an enlarged side elevation, partly cut away and in section, similar to FIG. 2 but adapted as in the instance of FIG. 5;

FIG. 7 is a transverse sectional view taken at VII--VII of FIG. 6; and

FIG. 8 is a transverse sectional view taken similarly to FIG. 7 but on a different apparatus embodiment of the invention.

In general, the objects of the present invention are accomplished in apparatus for treatment of a textile strand whereby the strand is drawn to increased length by draw rolls and is heated on one side by a hot fluid jet and maintained relatively cool on the opposite side by contact with a cooled draw roll.

A particular embodiment comprises strand-crimping apparatus for drawing a plurality of drawable textile strands alongside one another in a drawing zone, for heating the drawn strand material on one side only to its plasticization temperature by directing thereonto a stream of hot fluid, for maintaining the opposite side of the strands cooler than the plasticization temperature, and for withdrawing the strands substantially tension-free, whereupon they assume a crimped configuration.

FIG. 1 shows, in side elevation and partly schematically, strand 10 being withdrawn from supply package 11 by the nip of pair of supply rolls 13, 14 from which it passes to and through the nip of auxiliary roll 12, which may be undriven, and flanged cool roll 15, which is rotated at a sufficiently greater surface speed than the supply rolls to draw the strand to increased length by exceeding the elastic limit (usually reached in the vicinity of 10 percent elongation) but without breaking the strand. The increase in length usually is limited to several times the supply length, although with some undrawn strand compositions a draw of 6× or even higher may be feasible. A draw of about 4× is customary with nylon 6 and 66. The strand takes approximately a half turn about the flanged cool roll, to the recessed peripheral surface of which is juxtaposed jet end 21 of pipe 22 for hot fluid supplied from source 24 through valve 23 in the pipe. From the cool roll the strand is withdrawn and is forwarded, preferably at reduced rate, about part of roll 17, which is driven or not driven as desired, then past heater 18, and is traversed onto windup package 20 driven by surface contact with traversing drive roll 19. The cool roll rotates on axle 16 (shown sectioned).

FIG. 2 shows, also in side elevation but partly in section and considerably enlarged, a portion of cool roll 15 and adjacent elements. Part of near flange 25 of the roll is broken away, revealing the otherwise concealed corresponding portion of opposite flange 25' as well as jet end 21 and the adjacent length increment of strand 10. The roll has hollow 28 inside, which is supplied conventionally with cooling fluid (not shown). Jet end 21 is concave in the plane of the view, in juxtaposition to the recessed arcuate peripheral surface of the roll, with sufficient clearance for strand 10 (omitted in the interest of clarity) to pass therebetween. The jet outlet is aligned with bore 27 in pipe 22, and the emitted hot fluid (not shown) is incident at an oblique angle onto the exposed side of the strand, which runs about the roll in essentially nonslipping contact with that recessed peripheral surface thereof. The supply pressure of the hot fluid preferably is such that the velocity component thereof in the direction of strand travel exceeds the rate of travel of the strand.

FIG. 3 shows, in front elevation on the same scale as in FIG. 2, a portion of cool roll 15, without strand 10 on recessed peripheral surface 26 thereof, which is flanked by pair of flanges 25, 25'. This view is what would be seen upon looking leftward from a position to the right of cool roll 15 in the preceding views before the strand is strung thereon. When only a single strand (i.e., one "end") is treated on roll 15 the flanges, which together with the intervening roll surface confine the strand laterally over three quadrants of its circumferential surface, may be more closely spaced than the indicated spacing thereof, which is more conducive to multiple-ending, might suggest. With either a single end or a plurality of ends alongside one another it is desirable to confine the flow of hot fluid to the strand side exposed to the open quadrant.

FIG. 4 shows, also in front elevation and partly in section, the elements visible looking obliquely leftward at IV--IV in FIG. 2. Jet end 21 with outlet opening 29 therein is visible end-on, with part of pipe 22, and flanked by part of flanges 25, 25' (shown sectioned) of cool roll 15, which is not otherwise visible. Arrows from the outlet opening denote the flow of hot fluid therefrom which is predominantly upward in this view, corresponding to movement in the running direction of the strand rather than otherwise. The roll flanges also serve to channel the flow parallel to that direction instead of permitting it to be dissipated in any great part by a transverse velocity component.

The temperature of the hot fluid should be at or sufficiently above the plasticization temperature of the strand composition to soften the exposed side of the strand in the relatively brief time it is exposed thereto. For nylon the fluid temperature preferably is at least about a couple hundred degrees Centigrade. The cool roll should be maintained well below the strand composition plasticization temperature, preferably not more than about twice room temperature in degrees Centigrade. The cool side of the strand passes in essentially nonslipping contact with the peripheral surface of the cool roll.

The resultant configuration of the strand after cooling of the temporarily heated side, chiefly by conduction while still on the cool roll, is generally helical, with reversal of the helix direction back and forth along the strand length. Such configuration gives the strand a bulky or fluffy appearance, especially when composed of quite a few filaments. The effect upon a monofilament is similar though perhaps less extreme in overall effect because of the lack of other contorted filaments in the same strand. More than one strand may be treated side by side on the same roll if desired, especially where the strands are monofilaments or contain few filaments apiece.

FIG. 5 and succeeding views are devoted to illustration of adaptation of the foregoing means and method in or to treatment of a multiplicity of ends of strand side by side. The showing is quite similar to the illustration of treatment of a single strand end of FIG. 1 and intervening views, and like elements or components are designated in FIGS. 5 to 8 by reference numerals larger by one hundred than the reference numerals used in the preceding views. Where there is no substantial change in manner of operation, specific mention of at least some portion thereof is omitted in the interest of brevity.

FIG. 5 differs outwardly from FIG. 1 in that conical package 11 of that earlier view has been replaced by beam 111 from which strand 110 is unwound to pass between the nip of auxiliary roll 112 and cool roll 115, which looks similar to roll 15 of previous views. However, notwithstanding such similarity of roll 115 in this view and in FIG. 6, which shows a portion thereof enlarged, together with juxtaposed jet end 121 of pipe 122, FIG. 7 (taken sectioned thereon as indicated) shows configurational differences from previous roll 15.

FIG. 7 reveals the surface of roll 115 as being multiply recessed in a series of rounded grooves between alternate rounded lands to receive and flank strand ends (shown in place) 110a, b, etc., each of which may comprise numerous individual filaments or consist of a monofilament, of course. The edges of jet end 121 abut ungrooved edge portions of the roll surface just inside the flange wall so as to preclude lateral escape of the fluid, and the jet end is open clear across the grooved portion of the surface so that the fluid therefrom flows over all the strand ends as a group.

FIG. 8 shows alternative jet end 141 juxtaposed to the surface of smooth unflanged roll 135. The jet end has a plurality of separator webs 142 spaced between the sides thereof and also juxtaposed to the roll surface, forming therewith a number of compartments, each receiving one (or more) of strand ends 110a, b, c, d, e. Of course, as in the previous embodiments, the jet is spaced sufficiently from the roll 10 as not to interfere with rotation thereof. Also comb 108 between beam 111 and nip rolls 113, 114 and comb 109 between the nip rolls and cool roll 115 are present to align and space apart the plurality of strand ends. One such comb may suffice but two are preferred.

It will be understood that in these additional embodiments of this invention, as in the described embodiment, the rate of strand withdrawal from the package, as by the indicated nip rolls or the equivalent, is maintained sufficiently lower than the surface speed of the cool roll to impart the desired degree of tension to the strand ends therebetween, sufficient to draw the strands to increased length as desired. The subsequent forwarding roll is preferably driven at the same surface speed, while the windup rate is lower to enable the strand to relax at least partially before being wound up. Suitable means for so driving the respective driven rolls are well known in the art and accordingly do not require further comment or description here.

Although only imperfectly understood, the resulting helical crimp in the drawn strand may be at least partly attributable to a heat-induced molecular disorientation of the exposed side of the strand such as to preclude subsequent recovery thereof from the increased length imparted thereto by the previously applied tension, whereas the opposite side, which retained its molecular orientation and consequent elasticity, retracts slightly to become relatively shorter. The resulting difference in relative lengths of the respective opposite sides of the strand, apparent under low tension as a generally helical configuration, produces a bulky or fluffy condition, which is quite desirable, both from the standpoint of appearance and of its effect upon physical properties of textile products made therefrom, such as apparel, upholstery, and carpeting.

Heat relaxation after treatment on the cool roll may be performed by exposure of the cooled strand(s) to an intermediate temperature in heater 18, which is heated in any suitable manner, through which it passes at relatively low tension, or similar relaxation may be deferred until later if desired. The heat-relaxed strand exhibits a more tightly coiled configuration, as may be desirable.

The composition of the hot treating fluid may be selected for reasons of cost, heat-capacity, chemical plasticizing effect upon the strand composition, or other reasons. Gases are preferred because of the tendency of most liquids to wet the cool roll or the strand or both, which usually is undesirable. Hot air is quite useful accordingly, with or without the admixture of steam, for example. Some steam usually is helpful because of having a plasticizing effect, but excessive steam is usually undesirable because of problems arising from condensation of water on the apparatus. Combustion gases may be employed, such as acetylene or hydrogen with air or oxygen. Other examples of suitable hot fluids will occur to persons ordinarily skilled in the art in the light of the present teaching.

For best results the radius of the cool roll, in centimeters, should not exceed the cube root of the strand denier. Thus for a 1,040 d. strand of carpet yarn, the preferred maximum roll diameter is about 20 cm., and for a 15 d. monofilament about 25 cm.

No attempt will be made to list here the considerable variety of strand compositions subject to successful treatment according to the present invention. No reason is known to rule out any plasticizable strand having a generally linear polymeric composition and at least partially molecularly oriented with respect to the strand axis by predrawing or even by orientation during its formation by extrusion, for example. If desired the strand may be partially oriented before being drawn and crimped according to the present invention. Partially cross-linked or three-dimensional polymers, whether organic or inorganic, also may be suitable. One or more additional rolls may be added, in contact with the cool roll or between it and the nip rolls to preclude slippage for the purpose of ensuring drawing or simply as a precautionary measure.

Although certain preferred embodiments of this invention have been described above and illustrated in conjunction therewith, modifications therein, whether as above suggested or otherwise, as by adding, combining, or subdividing parts or steps, may be made while retaining all or some of the benefits of the invention, which is defined in the following claims.