US3376622A - Strand treatment - Google Patents

Description

April 9, 1968 R. K. STANLEY 3,376,622

STRAND TREATMENT Filed July 51, 1963 3 Sheets$heet l INVENTOR. ROBE/P7 A? JTA/Vlf) ATTOlF/VEX April 9, 1968 R. K. STANLEY 3,376,622

STRAND TREATMENT Filed July 31, 1963 3 Sheets-Sheet f v If 2 Q 7f 0 35 /l/ INVENTOR. 19049597" A? J 54/1 16? A 770P/VEX A ril 9, 1968 R. K. STANLEY 3,376,622

STRAND TREATMENT Filed July 31, 1963 3 Sheets-Sheet 5 INVENTOR. P0554 7 If. STA/V15 3,376,622 STRAND TREATNIENT Robert K. Stanley, Middletown Township, Delaware County, Pa, assignor to Techniservice Corporatiou, Lester, Pa, a corporation of Pennsylvania Continuation-impart of application Ser. No. 216,524, Aug. 13, 1962. This application July 31, 1963, Ser. No. 302,758

Claims. (CI. 2872) This invention is a continuation-in-part of Ser. No. 216,524, filed Aug. 13, 1962, now abandoned, and relates to treatment of textile strands, concerning especially crimping thereof by successive extension and compression along the strand axis.

Textile strands can be produced by extension of fiberforming compositions through spinneret orifices and collection of the resulting filaments or fibers. Many polymeric fiber-forming compositions so treated produce strands of relatively low tensile strength because of relatively low macromolecular orientation with respect to the longitudinal axis. In most such compositions the orientation and tensile strength can be increased readily because the strand components (usually continuous filaments) are drawable to an attenuated and extended condition of high orientation from which there is little or no tendency to return to the original condition. Nylon strands, for example, can be drawn so readily at room temperature that they are commonly indicated as being cold-drawable. In actual practice the strand, regardless of composition, may be heated to facilitate and to localize the drawing operation.

Strands of continuous filaments, whether oriented or unoriented, are inappropriate for many uses because of their rectilinearity, which is conducive to slickness, translucency, and low bulk, all of which can be eliminated or modified by any of a variety of processes usually called crimping or texturing. Nearly all of those processes (e.g., edge-crimping, gear-crimping, jet-crimping, and twist-crimping) tend to extend the strand axially while deforming it transversely of the longitudinal axis and, therefore, may be expected to be compatible with an immediate predrawing operation. stutter-crimping, however, which orients the strands by longitudinal compression thereof, may be expected to be separated from the crimping process in location or time (except for being prior, usually long prior) rather than adapted to follow immediately upon an attenuation of the strand to increased length. Attempts to crimp thermoplastic textile strands within a short time following drawing thereof have required that the strands be heated or wet during both steps or both heated and wet during one or both steps. There is a considerable need for improved apparatus, technique, and results.

A primary object of the present invention is provislon of a novel drawing and crimping process for textile strands.

Another object is crimping of textile strands by compression along the strand axis immediately following permanent extension therealong.

A further object is elimination of the customary requirement that thermoplastic strands be heated or wet (or both) during drawing and crimping.

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

FIG. 1 is a schematic representation of drawing and crimping steps with intervening time period;

FIG. 2 is a schematic representation of a continuous draw-crimping process without intervening time period;

States Patent G FIG. 3 is a perspective view (somewhat stylized) of a drawing system useful according to this invention;

FIG. 4 is a front elevation of a stuller-crimper for use according to this invention;

FIG. 5 is a side elevation of the stutfer-crimper of FIG. 4;

FIG. 6 is a sectional plan of the same stulfer-crimper taken at VI-VI of FIG. 5;

FIG. 7 is a front elevation of a modification of apparatus according to this invention;

FIG. 8 is a front elevation of a further modification of apparatus according to this invention;

FIG. 9 is a side elevation of a length increment of monofilament textile strand in unon'ented or only partly oriented condition;

FIG. 10 is a side elevation of the same increment of the strand of FIG. 9 after attenuation to increased length to orient it;

FIG. 11 is a side elevation of the oriented length increment of the strand of FIG. 10 buckling under axially compressive stress;

FIG. 12 is a side elevation of the same strand length increment crimped into a generally U-shaped configuration;

FIG. 13 is a side elevation (on reduced scale and somewhat stylized) of successive length increments crimped as in FIG. 12; and

FIG. 14 is a side elevation (on a much further reduced scale and also somewhat stylized) of a considerably greater length of crimped strand than shown in FIG. 13.

In general, the objects of the present invention are attained by attenuating a polymeric textile strand to increased length and immediately thereafter compressing the strand axially to buckle succesive length increments thereof, without necessity for the strand to be heated or wet (or both). The invention comprehends particularly such process as an improvement in stutter-crimping. Certain apparatus for drawing and immediately stutter-crimping textile strands comes within the purview of this invention, as indicated below.

FIG. 1 shows schematically zone 11 wherein a strand is attenuated to increased length or drawn and zone 13 wherein the strand is crimped, as by any conventional system. intervening zone 12, shown in broken lines and traversed by an arrow leading from zone 11 to zone 13, represents the period (excessive) of time intervening between drawing and crimping. FIG. 2 shows schematically drawing zone 15, wherein the strand is treated as in zone 11, and compressive crimping zone 16 contiguous thereto according to this invention. The arrow indicates the passage of the strand immediately to the crimping zone from the drawing zone without appreciable time intervening. The meaning of this limitation will be apparent from the following details of the apparatus and process of this inventron.

FIG, 3 shows, in perspective (stylized by omission of supporting, heating, driving, or other elements), rolls 21, 22, and 23 at the input end of a drawing zone, useful according to this invention, and rolls 31, 32, and 33 at the output end of the zone. Located in the space between the two sets of rolls is draw pin 27, use of which is optional. Strand 20, whose direction of travel is indicated by arrows, proceeds generally from left to right, passing about a quadrant of roll 21, downward through the nip of rolls 21 and 22, about the lower half of roll 22, upward through the nip of rolls 22 and 23, and over a quadrant of roll 23. It then makes a single turn about draw pin 27, after which it is denoted as 20. After leaving the draw pin the strand proceeds about a quadrant of roll 31, downward through the nip between rolls 31 and 32, about the lower half of roll 32, and then upward through the nip between rolls 32 and 33.

each of these two sets is driven by suitable motive means (not shown) and that all the rolls within each set rotate at constant speed, whether driven directly by the motive means or indirectly by contact (essentially non-slipping) with one another. The surface speed of the rolls in the second or forwarding set (31, 32, 33) is greater than the speed of the rolls in the first or input set. The draw pin does not rotate but is fixed so as to snub the strand passing about it. The pin may, but need not, be heated by any conventional means (e.g., electrically or by steam, preferably supplied internally) as is customary in the art of strand drawing.

With some strand compositions it may be helpful to heat one or both sets of rolls (in addition to, or instead of, the draw pin). Heating the first set of rolls preheats the strand for drawing, possibly rendering it easier to draw, and incidentally preheating it for crimping-as may the drawing step itself. Heating the second set of rolls at least sulficiently to prevent the drawn strand from cooling in the interim (however brief) is conducive to a steady and high degree of crimping. Although not illustrated, methods and means for heating the rolls, preferably internally, will come readily to the mind of a person skilled in the art; e. g., circulation of heated fluid therein, or by electrical means as disclosed in my patent application Serial No. 790,658 filed February 2, 1959 for Strand Crimping now Patent 3,111,740. The herein illustrated arrangement of three rolls in each set, with their axes in a common plane, two of the rolls flanking and being contiguous with the other roll is a preferred arrangement, but it is not imperative for the practice of this invention, as will be apparent hereinafter.

FIGS. 4, S, and 6 show, in front and side elevation and sectional plan, respectively, stuifer-crimper 41 useful according to this invention. Rolls 31, 32, and 33 are shown incorporated in this apparatus, the latter two functioning also as stuffing feed rolls. The supporting frame comprises base plate 42, front plate 43, back plate 44, and top plate 45, all secured together by suitable means (not shown). Upstanding facade 46 is secured similarly to the front plate. Tubular stuffing chamber 50, which is nearly square in cross-section, is held in place against the. front of the facade by four washers 51 overlapping the side edges of the front of the chamber and supported on four wing screws 52 threaded into suitable apertures in the facade. The front wall of the chamber overlaps portions of rolls 32 and 33, and the rear wall does likewise, down to the roll nip, while the side walls terminate adjacent the rolls, thereby forming a close-fitting entrance to the chamber for strand stuffed thereinto by the rolls. The upper end of the chamber is covered by cap 55, which has ears 56 overlapping the front and back walls of the chamber and pivoted thereto by pintles 57. Extension springs 59 stretched from pins 58 on the cap to pins 60 on the chamber walls bias the cap closed against the otherwise open top of the chamber.

Motor 61 affixed to the top surface of top plate has shaft 63 extending to the rear through journal 62 upstanding from and secured by bolts 67 to the rear face of back plate 44. Aflixed to the end of the motor shaft is pulley 64 interconnected by belt 65 to pulley 66 on the end of shaft 73, which carries roll 33 at its front end and extends through the front and back plates and also carries gear 69. Meshing with this gear is gear 68 on the end of shaft 72, the other end of which carries roll 32. Stub shaft 71 journaled in front plate 43 carries roll 31.

Located below rolls 32 and Bare several components not being used as stuffer-crimper 41 is shown in FIGS. 4, 5, and 6. They are guide block 75, affixed to the facade by screw 76, and overlying guide clip 77, which is secured to the guide block by bolt 78 at the side. Both the guide block and clip extend arcuately toward the nip of the rolls. Use of these guide elements (and non-use of roll t 4 31) appears in the embodiments shown in FIGS. 7 and 8, which are described hereinafter.

In the preferred embodiment already described, strand 20 is attenuated to become strand 20" in the drawing zone between first set of rolls 21,22,123 and faster running second set of rolls 31, 32, 33, the strand passing in es?v sentially non-slipping contact with the rolls in each group. Immediately and thereby molecularly oriented, strand 20' is fed upward through the nip of rolls into the entrance of chamber filled with accumulation 20 of crimped strand, shown (stylized, for clarity) in FIG. 4 by cutting away of part of the front wall of the chamber, and is otherwise unheated and may be positively cooled (e.g., by circulation of a coolantnot shown-between the exterior and interior walls thereof) as disclosed in my patent application Serial No. 790,658 filed Feb. 2, 1959 for Method and Apparatus for Strand Crimping now Patent 3,111,740.

Because the stufling chamber is always full during crimping operations each straight-length increment of strand entering the chamber is compressed axially (i.e., longitudinally) and is forced to buckle, much as an overloaded structural column buckles. Continual buckling of successive length increments at the chamber entrance produces a crimping of the strand. Of course, the continued stuffing of the strand into the chamber forces the terminal part of the strand accumulation therein to emerge gradually therefrom between the spring-loaded cap and the upper end of the chamber. Emergent crimped strand 20" is in relaxed condition and is wound up onto cone 79 driven by contact (through the layers of strand on it) with drive roll 80.

FIG. 9 shows, from the side, a short length of unoriented (or only partly oriented) rnonofilament strand 20. In transverse cross-section it is round, although that is not essential. FIG. 10 shows a like amount of strand 20', attenuated to increased length and thereby oriented. FIG. 11 shows the same length increment of strand 20' at an earlystage of buckling under axially compressive stress. FIG. 12 shows the samelength increment, now designated 20", completely buckled into a generally U- shaped configuration such as exists inside the confining chamber. FIG. 13 shows, on a much smaller scale, a longer length of strand 20", including several buckled length increments, showing the generally curved arms of the U-shaped configurations ,(or crimps) stylized to the extent of being shown apart or separated although in the chamber there is little or no such separation. FIG. 14 shows, on an even smaller scale, relaxed crimped strand 20" such as is produced according to this invention.

Although the drawings illustrate only a monofilament strand, it will be understood that the term strand as used herein includes also a multifilament strand and that shorter lengths (e.g., staple) than usually termed continuous may be present. Suitable strand compositions will come readily to the mind of a person skilled in the textile arts. Prominent among the suitable compositions are the nylons (polycarbonaniides), e.g., 66-nylon (i.e., polyhexamethylene adipamide), also 6-nylon, 11-

nylon, 610-nylon, and fiber-forming copolymers thereof,

including terpolymcrs. Other suitable polymeric materials for strands to be treated. according to this invention include most of the thermoplastic fiber-forming materials,

such as polyhydrocarbons (e.g., polyethylene, poly-.

propylene), polyesters (e.g., polyethylene terephthalate), polyacrylonitrile and copolymers of acrylonitrile with other vinyl compounds, also copolymers of vinyl chloride and vinylidene chloride, and polyurethanes. This list is simply exemplary and is not intended to be exhaustive of suitable compositions, most or all of which are thermoplastic.

If a heated draw pin is used the appropriate tempera-, ture for it will depend upon the characteristics of the strand composition and the speed of the strand over the after having been drawn to increased length 32 and ,33 and thus stuffed 50..The chamber itself is draw pin. Appropriate processing speeds lie in the range of from one hundred to one thousand yards per minute (y.p.m.), but somewhat slower or faster speeds may be employed. For 66-nylon at an input of 100 y.p.m. and output of 400 y.p.m. (draw of 4X) the draw pin temperature may conveniently be between 150 and 250 C. The speed at which the strand is fed into the stutfercrimper coincides with the output speed from the drawing Zone, of course, and the roll temperature preferably prevents the strand from cooling before entering the crimper.

As previously indicated, preheating of the strand is not required for crimping according to this invention and may not be required for drawing. The moisture content of the strand, if appreciable, may have a deleterious effect upon the desired treatment or its results. In general, therefore, the strand should not be wet, the preferable content of water (and/or any lubricant or softening, swelling, or plasticizing agent or solvent, all of which may be collectively referred to as moisture) being less than about A strand at such low moisture content may be considered as essentially dry or moisture-free for the purpose of the present invention. The relative humidity in and about the chamber should not exceed about for the usual textile strand compositions, the upper limit of humidity varying somewhat according to the moisture content and sensitivity of the composition.

While the illustrated three-roll arrangement is preferred at each end of the drawing zone, it is possible to use other roll arrangements, such as godets, if desired. The nip of rolls 32 and 33 may constitute a junction of the drawing and crimping zones, thereby effectively reducing to zero the length of the otherwise intervening path portion mentioned above. FIGS. 7 and 8 show (in front elevation, but rotated 90 clockwise) the crimper of FIGS. 4, 5, and 6 but with the strand passing therethrough being fed directly by and between rolls 32 and 33 in line with their common tangent (through the roll nip). Inasmuch as essentially non-slipping contact may be difficult to attain at a pressure that will not damage the strand, additional rolls ahead of rolls 32 and 33 may prove useful. When, as illustrated, the compressive crimping is accomplished by means of a stuifer-crimper, the end of the drawing zone should not be further from the beginning of the crimping zone than about three diameters (measured along the strand path) of the sufling rolls. Thus, in FIG. 7, added pair of nip rolls 82 and 83 are so located, and strand 20 passes therebetween. The rate of strand travel in such intervening portion of the strand path may be substantially the same as at the end of the drawing zone; it should not be less and may be more. In both FIGS. 7 and 8 the strand passes between guide block 75 and overlying clip 77 to center it along the nip of rolls 32 and 33. When using all three rolls, as in FIGS. 4 to 6, it may be desirable to locate a pigtail or other guide ahead of the first roll and centered from end to end thereof for a like purpose.

Other variations in or modifications of the described apparatus and process may be made without involving a departure from the inventive concept. Any similarly useful compressive crimping device may replace the illustrated stuffer crimper, which is merely exemplary, as is the spring-loaded cap as the device for applying backpressure to the strand accumulation in that crimper. Such a crimper may have a stufiing chamber with a round bore and a plunger therein as the back-pressure element, for example; also useful is a stuffer-crimper having a frictionally retarded back-pressure device of wheellike or gear-like configuration, as disclosed in U.S. Patent 3,027,619. Windup of the crimped yarn expelled from the chamber preferably should be synchronized to ac commod'ate the yarn so expelled without, however, withdrawing yarn from ahead of the back-pressure device;

the portion of the cap covering the chamber may be used to control the windup rate, or a sensing device inside the chamber, such as is disclosed in my patent application Serial No. 294,035, filed July 10, 1963, for Strand Crimping, which is well adapted to use with a stuffer-crimper of the type disclosed in U.S. Patent 3,027,619, may be employed.

Strands crimped according to the present invention are characterized by excellent crimp stability despite absence of conventional strain-relieving features, which have been customary despite the complication and expense attendant thereon. Other benefits and advantages of this invention, which produces crimped textile strands of exceptional bulk and crimp doubtless will become apparent and accrue to those who undertake to practice it as defined in the following claims.

The claimed invention:

I. A process for drawing and bulking yarns of synthetic continuous filaments, comprising the steps of forwarding an undrawn yarn of synthetic continuous filaments at a predetermined linear rate to the nip of rolls of a stufifer-box crimper;

rotating said nip rolls at a predetermined peripheral rate at least twice as great as said linear rate;

drawing said yarn by the nip of said rolls;

immediately thereafter crimping said drawn yarn within said crimper;

and discharging the crimped yarn from said crimper at a linear rate less than said peripheral rate.

2. Process according to claim 1, wherein the peripheral rate is about four times as great as said linear rate.

3. Process according to claim 2, wherein the yarn is composed of nylon filaments,

4. A process for drawing and bulking yarns of synthetic continuous filaments, consisting of the steps of forwarding a drawable yarn of synthetic continuous filaments at a predetermined linear rate to the nip rolls of a stutter-box crimper;

rotating said nip rolls at a predetermined peripheral rate at least twice as great as said linear rate; locating the point of draw at a friction means positioned up-stream of the nip rolls;

drawing said yarn by the nip of said rolls;

immediately thereafter crimping said drawn yarn within said crimper;

and discharging the crim ped yarn from said crimper at a linear rate less than said peripheral rate. 5. A process for drawing and bulking synthetic continuous-filament, yarns consisting of the steps forwarding an at least partially undrawn yarn synthetic continuous filaments at a predetermined linear rate to the nip rolls of a stufl'er-box crimper;

rotating said nip rolls at a peripheral rate at least twice as great as said linear rate;

drawing said yarn by the nip of said rolls;

immediately thereafter crimping said drawn yarn within said crimper;

discharging the crimped yarn from said crimper at a linelar rate less than said peripheral rate;

and controlling said linear rate of discharge to maintain the frequency of crimp uniform.

References Cited UNITED STATES PATENTS 2,419,320 4/1947 Lo'hrk-e 2872 3,167,846 2/ 1965 Iwnicki et al. 28-1 3,177,556 4/1965 Van Blerk 281 2,686,339 8/ 1954 Holt 28-72 2,917,806 12/ 1959 Spence et a1. 196 6 3,111,740 11/1963 Stanley 28-1 LOUIS K. RIMRODT, Primary Examiner.

UNITED STATES PATENT DFFICE CERTIFICATE OF CORRECTION Patent No. 3,376,622 April 9, 1968 Robert K. Stanley et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 11, "invention" should read application lines 44 and 45, "crimping" should read drawing line 45, after "for" insert such drawing Column 3, line 27, and

column 4, line 19, after "Crimping", each occurrence, insert a comma. Column 4, lines 18 and 19, cancel "for Method and Apparatus". Column 5, line 46, "suffing" should read stuffing Column 6, line 49, yarns" should read yarns, same line 49, after "steps" insert of line 50, after "yarn" insert of Signed and sealed this 11th day of August 1970, (SEAL) Attest:

Edward M. Fletcher, Jr. JR.

Attesting Officer Commissioner of Patents

Claims (1)

1. A PROCESS FOR DRAWING AND BULKING YARNS OF SYNTHETIC CONTINUOUS FILAMENTS, COMPRISING THE STEPS OF FORWARDING AN UNDRAWN YARN OF SYNTHETIC CONTINUOUS FILAMENTS AT A PREDETERMINED LINEAR RATE TO THE NIP OF ROLLS OF A STUFFER-BOX CRIMPER; ROTATING SAID NIP ROLLS AT A PREDETERMINED PERIPHERAL RATE AT LEAST TWICE AS GREAT AS SAID LINEAR RATE; DRAWING SAID YARN BY THE NIP OF SAID ROLLS; IMMEDIATELY THEREAFTER CRIMPING SAID DRAWN YARN WITHIN SAID CRIMPER; AND DISCHARGING THE CRIMPED YARN FROM SAID CRIMPER AT A LINEAR RATE LESS THAN SAID PERIPHERAL RATE.

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