US2077441A - Textile yaen - Google Patents

Description

April 20, 1937. TAYLQR AL 2,077,441

TEXTILE YARN Filed Sept. 29, 1934 ATTORNEYS smooth character.

Patented Apr. 20, 1937 UNITED sTATEs PATENT OFFICE ton, Spondon, near Derby, England, assignors to Celanese Corporation of America, a corporation of Delaware Application September 29, 1934, Serial No. 746,258 In Great Britain February 5, 1932 9 Claims.

This invention relates to yarns having a basis of continuous filaments, but presenting the appearance of spun yarn, i. e., yarn made from staple fiber.

5 This application is in part a continuation of our application S. No. 712,120 filed 20th February, 1934 as a continuation in part of our application S. No. 652,780 filed 21st January, 1933, now Patout No. 1,959,142, May 15, 1934.

Spun yarn having a continuous filament basis is usually manufactured by cutting the contin-- uous filaments, e. g. waste filaments, into comparatively short uniform lengths and then subjecting the staple fibers thus produced to a series of operations similar to those accorded to natural fibers such as cotton or wool, including opening, carding or gilling, drawing, and spinning. The actual operations are appropriate to the length of the fiber, this being say 1 inches or 2 inches 2 if cotton type machinery is employed, or 3 /2 inches or more if wool or worsted machinery is employed. Special difilculties arise in the conversion of the separate, smooth fibers into. yarn, and the product, since it involves the use of a 25 long series of slow operations, is relatively costly. Moreover, yarns formed by spinning operations of the type indicated above on preformed fibers (whether naturally occurring fibers or fibers formed by transforming longer filaments or fibers 30 into short lengths) are invariably characterized by considerable variation in thickness along their length, some parts containing less fibers in their cross-section than others, and definite slubs appearing at intervals of 2 or 3 to feet. Simi- 35 larly, thin places appear at intervals, the occurrence of the slubs and thin places varying with diiferent classes of yarn. This inability of the ordinary methods of spinning preformed fibers to arrange the fibers in uniform quantity along the length of the yarn produced is' particularly evident on close inspection of woven or knitted fabrics of fine staple fiber yarns made by these methods.

Thus, in ordinary spun yarns, slubs occur hav- 45 ing a diameter up to 50 or 100% or even more in excess of the diameter of the yarn adjacent to the slubs, and such change in diameter is readily apparent in fabrics in which the yarns are employed, particularly when the fabrics are of fine, Again, the yarns may have thin places with a diameter as low as 70 or even 50% of the adjacent yarn.

The yarn according to the present invention is one which, while having the general appearance and other valuable properties of spun yarn, comprises cut filaments twisted together, the yarn being free from departures in diameter of more than 20% as compared with the average diameter of the yarn, that is to. say, any thickened or thinned places in the yarn show at the most a variation in diameter of about 20% from the portions of the yarn immediately adjacent such places. The yarn may evenhave variations in diameter of no more than or even less than 10%. Variations of the order mentioned are so small that the yarn for most practical purposes can be regarded as uniform.

This uniformity is a particularly valuable property of the yarn. Moreover, since the fibers in the yarn consist of cut filaments, they have substantially the same physical properties as the original uncut filaments; in particular, the original extensibility of the material is retained in the fibers which may, therefore, havev an extensibility of say 12, 14, 16 or 20%, depending upon the extensibility of the original filaments. The high extensibility of the new yarn is a factor of I considerable value both as regards the applicability of the yarn to subsequent textile operations and the elasticity and softness of products containing the yarn.

By reason of these important factors the yarn according to the invention, though of a fibrous character, possesses features previously found only in continuous filament yarns, andin particular the filamentous fibers of the yarn are disposed with a uniformity closely comparable with that of continuous filament yarn.

' The fibers formed by subjecting a bundle of continuous filaments to a cutting action in the production of the new yarn may be of varying length, yet, notwithstanding this, uniformity of the order stated may readily be obtained, the numbers of fibers at all points in the length of the yarn being the same as the number of filamerits in theoriginal bundle, subject to any small displacement that may take place of fibers or loose ends of fibers.

The product may have any desired degree of twist, appropriate to the use to which it is to be put. Quite a surprising strength is obtained with only a low degree of twist, and the elasticity and softness are correspondingly high.

The range of fiber length in any particular yarn may be considerable, there, however, usually being a preponderating number of fibers the length of which is near the average fiber length, with a number of fibers of greater and lesser length than that of this preponderating number. Notwithstanding this variation in length, the appearance of the yarn of a particular average length of fiber is very similar to that of ordinary spun yarns composed of fibers the uniform length of which is substantially the same as such average length. Thus, a yarn according to the invention composed of artificial filaments cut into lengths ranging from say 3 inches to 20 inches or 22 inches and' having an average fiber length of about 8 inches is very like a worsted yarn all the fibers of which are about 8 inches in length.

The considerable strength of the yarns according to the invention is probably due to the assistance afforded by the cut filaments of more than the average lengthin holding all the filaments together. This is noticeable by comparison with spun yarn made by the ordinary methods from out fibers of uniform length, the yarn according to the invention having .a similar strength .to that of ordinary yarn of much higher twist. As previously indicated, this results in the new yarn exhibiting a high degree of elasticity and softness.

Apart from the high quality of the yarn as regards strength, elasticity, and softness, the yarn enables fabrics to be made that are surprisingly even in character and particularly pleasing because of their freedom from objectionable slubs or streaks.

The yarn may consist of cut filaments of a wide variety of material, both natural and artificial, for example filaments of natural silk, or artificial filaments of cellulose acetate or other organic derivatives of cellulose, e. g. other cellulose esters, such as cellulose formate, propionate and butyrate, and cellulose ethers, such as ethyl and benzyl cellulose, and reconstituted cellulose such as viscose, nitrocellulose and cuprammonium artificial silk. It may likewise consist of a mixture of two or more of the above types. One such yarn may be doubled with one or more other yarns of any desired type. For example, two or more of the yarns containing the cut filaments may be doubled together for the purpose of increasing the denier or counts of the yarn and improving the regularity, or for any other purpose such as the production of yarn containing filaments or fibers having different dyeing properties. Thus, cellulose acetate fibrous yarn may be doubled with similarly formed fibrous yarn of natural silk or reconstituted cellulose artificial silk, orwith ordinary continuous filament or fibrous yarns.

Where the basic yarn consists of artificial filaments, these may be of alustrous character, or they may be of subdued or reduced luster. Filaments of different luster may be contained in a single yarn.

The yarns according to the invention have a wide range of application in the textile industry, whether used lone orin conjunction with other materials in the manufacture of woven, knitted, or otherwise formed fabrics or articles. For example, with average fiber lengths corresponding to thefiber lengths of wool of various grades, the yarns are particularly suitable for knitting fabrics ranging from the relatively heavy to those ordinarily obtainable only by the use of the very costly fine woolen yarns. At the same time, there can be obtained such advantages as, for example, controlled luster and, in. the case of cellulose acetate yarns, low shrink-- ing peculiar to the materials of which the yarns are composed.

The yarns can be prepared from the continuous filament materials in a number of ways by simple operations which, while breaking the continuity of individual filaments, do not interfere with the continuity of the material as a whole. These operations involve subjecting a bundle of continuous filaments to a cutting action occurring more or less at random among the individual filaments of the bundle so as to sever the filaments into lengths. A certain amount of initial twist and/ or the addition of twist during the operation enables the points of cutting to be distributed among the several filaments of the bundle.

Various methods of producing the yarns according to the invention will now be described with reference to the accompanying drawing, in which- Fig. 1 shows the conversion of a continuous filament yarn following its withdrawal from a twisting spindle;

Fig. 2 shows the conversion of a yarn as it is being delivered to a twisting and winding device;

Fig. 3 isa plan view of a detail of Fig. 2;

Fig. 4 shows a different type of apparatus in which use is made of the special roller arrangement shown in Fig. 5; 1

Fig. 6 shows an apparatus generally similar to that shown in Fig. 4 but modified in various respects; and

Fig. 7 shows an apparatus making use of an endless abrasive band.

Referring to Fig. 1, a yarn ll] of say 250 or 300 denier is drawn from a bobbin ll rotated so as to impart say 5, 8, or 10 turns per inch of twist to the yarn. The twisted yarn is led over a roller I2 covered with an abrasive l3 such as emery or glass paper, the yarn being drawn at a predetermined rate by means of a take-up device I4.

Because the yarn l l is drawn over the abrasive I3, its several filaments are subjected to the cutting action of the abrasive particles. Since, more over, the yarn is being twisted by the rotation of the bobbin II, the yarn itself is rotating as it passes over the abrasive, so that different filaments in turn are subjected to the cutting action. Upon any particular filament, the frequency of cutting is somewhat irregular, due to the irregular nature of the abrasive material and to the irregularity with which any filament comes into contact with a cutting particle. The continuous filaments are therefore severed into fibers of varying length.

At any one point in the yarn, at the most only a few of the filaments are severed, and continuity of the yarn is therefore maintained. Control over the average length of fiber may be effected by regulating the rate of passage of the yarn I I over the roller I2 and by varying the rate of rotation of the roller.

, In Fig. 2 a yarn [5 is taken at a predetermined rate by a feedroller l6 from any suitable supply, e. g. a dry-spinning apparatus I1, and fed to a twisting apparatus such as the cap-spinning apparatus l8. In passing from the balloon guide 19 to the edge of the cap 20 and so on to the bobbin 2|, the yarn forms a balloon 22 rotating round the cap. Between the guide I9 and the top of the cap, the yarn passes through the opening of a ring 23, and is carried against a series of teeth 24 formed by notching the inner edge of the ring.

In the balloon'22 the yarn is receiving twist and thus rotates upon itself as it passes over the teeth 24. At the same time the yarn is travelling endwise'as it is being wound on the bobbin 2|. Therefore different filaments of the yarn come in turn into contact with the teeth 24 and the filaments are converted into fibers of varying length. The twist imparted during the operation firmly binds the filaments into a coherent yarn.

In starting the operation, the yarn is passed through the slot in the ring 23, and then retates in the direction shown by the arrow. The frequency of cut depends on the number of teeth 24 in the ring 23, the rate of feed of the yarn, and the rate of twisting.

Referring now to Fig. 4, this shows an entirely different method of effecting the cutting of the filaments. The yarn 26 is led from any suitable source, e. g. the bobbin 21, to a pair of rollers 28, 29, of which the roller 29 is fluted (being preferably of metal) while the roller 29 consists of a resilient core 30, e. g. of soft rubber or sponge rubber, surrounded by a flexible sleeve 3|. The roller 29 presses lightly on the fluted roller 28, preferably by its own weight.

Below the roller pair 28, 29 is a second pair of rollers 32, 33, the roller 32 being fluted and the roller 33 surfaced with material such as rubber or leather. The roller 33 presses heavily against the roller 32, the pressure in conjunction with the fluted surface of the one roller and the resilient surface of the other causing the yarn to be firmly gripped as it passes between the rollers after leaving the first pair 28, 29.

To provide for this pressure, the roller 33 is carried on a depending arm 34 pivoted at 35, to which arm is connected a cord or the like 36 carrying a weight 31.

The roller 32 is driven at a speed considerably higher than the speed at which the roller 28 is driven, and, because of the firm pressure applied by the roller 33, tends to draw the yarn 26 through the rollers 28, 29 at a speed much greater than the peripheral speed of the rollers. Only a light pressure being exerted on the yarn by the roller 29 to press the yarn against the flutes of the roller 28 and the resilient core of the roller 29 en-- abling the flexible surface 3| of the roller to give somewhat, the rollers 28, 29 slip on the faster moving yarn.

The filaments" of the yarn are thus subjected to a slipping grip action, the flexible covering of the roller 29 nipping filaments in turn against the flutes of the roller 28 and cutting them cleanly.

A slight degree of twist in the yarn 26 enables the points of cutting to be well distributed over the yarn, but, by reason of" the random incidence of the cutting, the filaments are severed into fibers of a length which may vary in accordance with such factors as the speed of the operation, the difference in speed between the two pairs of rollers, the twist in the yarn, the size of the filaments, and the pressure exerted on the filaments at the first pair of rollers. For example, higher operating speed and/or lower pressure on the filaments may produce greater variations between the fiber lengths of a particular staple fiber product than lower speed and/or higher pressure. Control over the appearance and properties of the product may therefore be obtained by suitable adjustment of the operating conditions.

Preferably, the pressure at the rollers 32, 33 is sufliciently high to avoid slippage of the material in passing through these rollers, so that the linear output of the apparatus is substantially equal to the peripheral speed of the rollers 32, 33. Very light pressure by the roller 29 enables the yarn to be withdrawn from the bobbin 2! at substantially the same speed as that at which it leaves the rollers, the denier or count of the material being substantially unchanged in the operation.

On leaving the rollers 32, 33, the filaments now converted into fibers are twisted and wound by the cap-spinning device 38.

In Fig. 6, the yarn 39 is drawn from a bobbin 40 rotated to impart say 3 turns per inch of twist to the yarn. The twisted yarn passes through two pairs of rollers 4|, 42 and 43, 44, the rollers 4|, 43 being fluted similarly to the rollers 28, 32 of Fig. 4 and driven with a similar difference of speed, and the rollers 42, 44 being similar to the rollers 29, 33 respectively of Fig. 4.

Both rollers 42, 44 are carried by a frame 45 on an arm 46 pivoted at 41, a cord or the like 48 loaded with a weight 49 being connected to the frame 45 to cause each roller to engage with any desired pressure against its corresponding roller 4| or 43. As with Fig. 4, the rollers 43, 44 draw the yarn 39 through the rollers 4| 42, these latter slipping on the yarn and cutting the filaments into fibers of varying length.

Some at least of the twist in the yarn as it reaches the rollers 4|, 42 is retained after conversion of the filaments into fiber. Further twist may be added after the yarn leaves the rollers 43, 44.- In Fig. 6, such further twist is imparted by the ring spinning device 50.

Referring to Fig. 7, a bundle of filaments 5| is fed between a roller 52 and an endless abrasive band 53 guided by rollers 54 and led over a roller 55, any or all of the rollers serving to drive the band. The roller 55 supports the band 53 at the point where the bundle 5| is pressed against it by the roller 52. The bundle is drawn past the band 53 and roller 52 by means of a pair of rollers 56, 51, which exert a firm grip on the bundle and f are driven at a peripheral speed in excess of that of the band 53 so that the bundle is caused to slip over the surface of the band.

By reason of the pressure between the roller 52 andthe band 53 (supported by the roller 55) and the slip permitted by these members, the bundle drawn between the roller and the band has its filaments severed at frequent intervals so that after leaving the cutting point the bundle contains staple fibers.

Instead of the roller 29 or 42 being resilient, it may be rigid but light in weight so as to apply only a light pressure to the filaments. Again such roller may itself have a cutting action on the filaments.

Since the yarn treated in the apparatus shown in Figs. 4, 6 and 7 is converted into fibers by a cutting action resulting from light pressure of the filaments of the yarn against a cutting surface (the filaments being able to slip over the cutting surface), the fibers have substantially the same extensibility as the original filaments. For example, continuous filament yarn of from 16-20% extension converted in this way into fibrous yarn gives an extension in the final yarn (twisted to 2 -5 turns per inch) of from 12-14%, which makes the yarns very easily handled in knitting, weaving etc. and gives fabrics having a soft handle.

The conversion of the filaments into fibers by a cutting action is important, not only because it provides for the substantial uniformity in weight of the staple fiber yarn, but also because it enables the fibers to remain elastic and soft in handle, This result cannot be achieved by any conversion operation relying on tensioning the filaments to breaking point, since the stretching of the filaments before breakage very materially reduces their extensibility; the fibers thus produced are hard and wiry, and fabrics made from yarns containing the fibers are extremely harsh in handle.

The continuous fibrous material produced from the plurality of continuous filaments has at least sufficient twist to bring about cohesion between the fibers and therefore to maintain its continuity. It may have such twist immediately upon the conversion of the filaments into fibers to enable it to be used as yarn in textile operations or, in some cases, further twist may have to be added, e. g. if harder or stronger yarns are required. It is therefore to be understood that the term yarn is employed in the appended claims to connote a continuous fibrous material whether such continuous material is lightly twisted or possesses a higher degree of twist.

What we claim and desire to secure by Letters Patent is:--

1. A continuous fibrous yarn derived from a bundle of continuous filaments and composed entirely of cut filaments in which at least a part of each cut filament occupies substantially the same position with respect to its neighbors that it had prior to cutting.

2. A continuous fibrous yarn of cellulose acetate derived from a bundle of continuous filaments and composed entirely of out filaments in which at least a part of each cut filament occupies substantially the same position with respect to its neighbors that it had prior to cutting.

3. A continuous fibrous yarn derived from a bundle of continuous filaments and composed entirely of cut filaments in which at least a part of each cut filament occupies substantially the same position with respect to its neighbors that it had prior to cutting, said yarn being free from diameter variations in excess of 20% of the average diameter of the yarn.

4. A continuous fibrous yarn derived from a bundle of continuous filaments and composed entirely of cut filaments of varying length in' which at least a part of each cut filament occupies substantially the same position with respect to its neighbors that it had prior to cutting.

5. A continuous fibrous yarn derived from a bundle of continuous filaments and composed entirely of cut filaments of varying length in which at least a part of each cut filament occupies substantially the same position with respect to its neighbors that it had prior to cutting, said yarn having substantially the same uniformity of diameter as a continuous filament yarn.

6. A continuous fibrous yarn derived from a bundle of continuous filaments and composed entirely of cut filaments in which at leasta part of each cut filament occupies substantially the same position with respect to its neighbors that it had prior to cutting, the cut filaments being of varying length, the average length of said filaments being substantially equal to the length of wool fibers.

7. A continuous fibrous yarn derived from a bundle of continuous filaments and composed enof each cut filament occupies substantially the same position with respect to its neighbors that it had prior to cutting, the cut filaments being of varying length, the longer and shorter filaments being substantially uniformly distributed throughout the length of the yarn.

8. A continuous fibrous yarn derived from a bundle of continuous filaments and composed entirely of cut filaments in which at least a part of each cut filament occupies substantially the same position with respect to its neighbors that it had prior to cutting, said yarn having an extensibility of at least 12%.

9. A continuous fibrous yarn derived from a bundle of continuous filaments and composed entirely of cut filaments in which at least a part of each cut filament occupies substantially the same position with respect to its neighbors that it had prior to cutting, the cut filaments being of varying length, there being a preponderating number of cut filaments substantially equal to the average length and a small number of cut filaments of a length greater and less than said average length, said yarn being free from diameter variations in excess of 20% of the average diameter of the yarn.

MATTHEW MICHAEL TAYLOR. STEPHEN MILLER FULTON.

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