US3468118A - Bulked yarn - Google Patents

Description

Sept. 23, 1969 B. DANIELS ET AL BULKED YARN Filed March 13, 196'? l ATTORNEYS United States Patent O M U.S. Cl. 57-140 4 Claims ABSTRACT F THE DISCLOSURE Bulked yarn comprises filaments which have a combination of different sinusoidal crimp frequencies superimposed one on another as by means of a sequence of gearcrimping assemblies.

The invention concerns improvements in or relating to bulked yarn.

Bnlked yarn, in the context of this specification, means multifilament yarn composed of continuous filaments of man-made material, as for instance synthetic thermoplastic material, the filaments of which have been crimped, looped waved or otherwise distorted so as to impart increased bulk to the yarn compared with its state before such treatment. It is usual to refer to the number of such crimps etc., occurring in unit lengths as the Crimp frequency.

The bulked yarn of the invention which, in view of its versatility in a number of ways and in a number of uses, is an advance over known bulked yarns, comprises a multifilament yarn the filaments of which exhibit sinusoidal crimp of differing crimp frequencies.

By sinusoidal crimp we mean a crimp whose amplitude varies cyclically in both positive and negative directions, bnt not necessarily with a pure sine wave motion.

The relative proportions of the differing crimp frequencies may remain constant along the length of the yarn or they may vary cyclically or intermittently, whether in random or in regular-fashion, along the length. Furthermore the respective crimp frequencies may be constant or varying in value, along the length of the yarn.

In a particular embodiment of the invention, the crimp is produced by crimping between gear-wheels or other denticulated members. Using such means, a yarn can be produced containing filaments each having a combination of the crimp frequencies, the one superimposed on the other or others.

One convenient way of making the bulked yarn of the particular embodiment of the invention is by the process of crimping described in application, Ser. No. 622,640, filed Mar. 13, 1967, now abandoned, by which process heated multifilament yarn is drawn and crimped in apparatus including two assemblies of denticulated members and is optionally cooled between said assemblies, and the construction and speed of the members of one assembly differ, according to specic combinations, from those of the other.

One typical bulked yarn according to the invention consists of a 400 denier/50 filament yarn of polyhexamethylene adipamide, more than half the filaments of which are crimped with a combination sinusoidal crimp in which 38 crimps per inch are superimposed on 20 crimps per inch, and of the remaining filaments, some are crimped with a sinusoidal crimp of 20 crimps per inch and the remainder with a sinusoidal crimp of 38 crimps per inch. Skein length difference (L20-L5), is of the order of 1.0-1.5.

3,468,l i8 Patented Sept. 23, 1969 ICC The reference to skein lengths L in inches with numerals appended, are measures of the primary and secondary crimp in the yarn determined by a test method in which a certain number of wraps for singles yarn, l5 to 3-fold heavy denier yarn) of yarn are taken around a l-metre reel, the skein so wound is suspended in hot water C.) and the length of the skein measured under two different loadings, the first being large enough to pull out the secondary crimp (but allow the primary crimp to be manifested or developed) and the second being insuicient to pull out the secondary crimp (the actual loads depending on the size of the yarn in question and being 20 and 5 grams respectively for the lower denier (400 denier) yarns, and 60 and 10 grams respectively for the higher denier (1040 denier) yarns.

Such bulked yarn can be produced by a hot-gear-crimping process, as described in said application, Ser. No. 622,640, in which two assemblies of gears are employed to act on the yarn between the snubbing-pin and the draw roll of a drawing machine, the two assemblies differing from one another, according to specific combinations, as to their speed and the number of teeth per inch and degree of intermesh, and the yarn optionally being cooled between said assemblies.

In one such process, the first gear-Wheel assembly had 38 teeth per inch and 0.021 inch intermesh, and the second assembly had 20 teeth per inch and an intermesh of 0.037 inch. The gear-wheels in both assemblies had outside diameters of 3.0445 inches. The gear-wheels of the first assembly were run at 1400 r.p.m., and those in the second assembly at a speed in the range 1600-1700 rpm., the feed roll speed being 512 feet/minute and the draw roll speed being 2,000 feet/minute. The yarn was heated by passage in 2 wraps around the snubbing-pin which was internally heated to 160 C. and between the two assemblies it was cooled by air from a nozzle emerging at a rate of 63 litres/minute.

In another such process, the first gear assembly had 20 teeth per inch and the second had 5 teeth per inch, the gears in both sets being of 3.0445 inch outside diameter. The gears of each assembly were run at 1100 r.p.m.; and the feed roll speed was 500 feet/minute, and draw roll speed 1500 feet/minute. Under these conditions 3630 denier/68 filament undrawn nylon 66 yarn was drawn and crimped such that the Skein length difference (L60-L10) was 2.2 and the yarn was composed wholly of filaments in which the 20 crimps per inch frequency was superimposed on the 5 crimps per inch frequency. The tension in the yarn between the gear assemblies was 395 grams; and between the second gear assembly and the draw roll, 330 gra-ms.

In the above-described second process, if the draw roll was not used, the yarn with superimposed crimps was produced when the second gear assembly was run at 1350 r.p.m., and the first at 1300 r.p.m., the Skein length difference (L60-L10) being 1.7; and the tension between the gear assemblies being 540 grams, and balloon tension of the ring-spindle wind-up 70' grams.

The bulked yarn of the invention can consist of filaments the crimp frequency of each of which differs intermittently, either in regular or random fashion, along their length. Such yarns can be produced by so varying the conditions of crimping, e.g., by tandem gear-wheel assemblies, that first one crimp frequency predominates and then another. In the case of gear-wheels, the crimp frequency of the assembly having the greater peripheral speed at any given time will tend to predominate; and variation of the relative speed setting will lead to variation in the nature of the crimp in the yarn, from a state where one crimp frequency wholly predominates through a state where that crimp frequency predominates but the other frequency is also present to a minor degree, though the true superimposition state, thence to the state Where the other crimp frequency predominates but the rst one is also present to a minor degree, finally to the state Where the second crimp frequency Wholly predominates.

The bulked yarn of the invention is advantageous in that the crimps in the filaments are not in register for any substantial length of yarn, as may be the case for instance with conventionally gear-crimped bulked yarns; and in that the yarn is more versatile than ordinary bulked yarns, being useful across a Wider spectrum of fabrics.

The bulked yarn of the invention is illustrated by the attached photograph of a single iilament showing a combination of low and high crimp frequencies along its length.

The latter advantage results from the fact that the optimum crimp frequency for, say, good stitch clarity n a knitted fabric is contrary to the requirement for good fabric bulk, and vice versa. The bulked yarn of the invention, especially when it contains iilaments having one crimp superimposed on another, effectively meets both requirements by virtue of the presence of both crimps.

The bulked yarn of the invention is preferably cornposed of filaments of synthetic thermoplastic material, as for instance nylon, Terylene polyester libre, and polyproylene; but equally it can be composed of other manmade filament materials, like cellulose acetate.

We claim:

1. A bulked multilament yarn containing laments which exhibit sinusoidal crimp of differing crimp frequencies, characterised in that certain at least of the filaments have a combination of different sinusoidal crimp frequencies, the one superimposed on the other or others.

2. A bulked multilament yarn according to claim 1 in which, of the remainder of filaments in the yarn, each has one or the other of said crimp frequencies singly.

3. A bulked multiiilament yarn according to claim 2 having two said crimp frequencies, one of high crimps per inch and the other of 10W crimps per inch, and in which in the remainderV there are laments with all low crimp frequency and iilaments With all high crimp frequency. Y l

4. A bulked multitilament yarn according to claim 2 in which the predominance of the respective crimp frequencies varies along the length of the yarn.

References Cited UNITED STATES PATENTS 2,326,174 8/ 1943 Rutishauser 28-1.3

3,166,820 1/1965 Taul et al. 28-1 2,369,395 2/1945 Heymann.

2,997,838 8/1961 Sinski 57-140 XR 3,013,379 12/ 1961 Breen 57-140 XR 3,175,348 3/1965 Bloch.

3,188,790 6/1965 Hebeler 57-140 3,208,125 9/1965 Hall et al. 57-140 XR 3,255,580 6/1966 Garner 57-140 3,259,953 7/ 1966 Baer.

3,262,257 7/1966 Martin 57-157 XR 3,263,298 8/1966 Holton 57-157 XR 3,309,855 3/1967 Stoll et al. 57-157 XR DONALD E. WATKINS, Primary Examiner U.S. Cl. X.R.

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