US2541181A - Staple fiber - Google Patents

Description

N. S. WELTON STAPLE FIBER Feb. 13, 1951 Original Filed Aug. 15, 1942 INVE TOR. \5. 1.622.

Patented Feb. 13, 1951 STAPLE FIBER 'Norman S. Welton, Nitro, W. Va., assignor to American Viscose Corporation, Wilmington, Del., a corporation of Delaware Original application August 15, 1942, Serial No.

454,963,. now Patent No. 2,411,644, dated November 28, 1946. Divided and this application December 5, 1945, Serial No. 632,855

8 Claims. 1 This invention relates to a novel staple fiber product. This is a division of application Serial No. 454,963, filed August 15, 1942, now Patent 2,411,644.

It is well recognized that the tendency of.

staple fibers to cohere is a highly desirable property forimproving the strength and handle of the textile materials made therefrom such as yarns, felts, and the like, and that this property of coherence of the fibers has a great influence upon subsequent textile processing, such as carding, spinning, and the like. In order to enhance this tendency of staple fibers to cohere, it has been the practice heretofore to impart a crimpiness'to the entire length of the continuous filamentary material from which the fibers are cut or to the entire length of the fibers after they are cut from a continuous filamentary tow of little or no crimp. Such treatments involve a special step of mechanical or chemical processing of the tow or fibers. It has now been found possible to obtain much of the desired coherence and concomitant properties by a novel procedure of cutting claimed in the above-mentioned application which imparts an irregular condition to the ends of a portion of the fibers. This irregular condition comprises any one or more or all of a number of characteristics consisting of irregularly-spaced microscopic corrugations extending partially or completely around the fiber, mangled and torn portions having irregular barb-like projections or a crimpiness along the end portions of the fibers It has been found that the presence of such irregularities along a minor portion of the lengths of the fibers even where present in but a minor proportion of the entire lot of fiber to be spun or otherwise processed. imparts a marked improvement in their properties, and especially in their coherence.

Accordingly, it is the object of this invention to provide a novel staple fiber product having improved cohesive properties by virtue of the presence of a crimpiness, barb-like projections, or irregular corrugation or acombination of these characteristics in a minor portion of the length of the individual fibers. .Further objects and advantages of the invention will appear from the drawing and the description thereof hereinafter. In the drawing, illustrative of the invention, Figure 1 is a plan view of one form of cutting device capable of accomplishing the invention,

Figure 2 is an enlarged view of a portion of the device oi Figure 1 showing more clearly the relationship of the cutting elements, and

Figure 3 is a drawing illustrating on an enlarged scale a fiber, one end of which has been cut and crimped in accordance with the present invention.

In general, the process for producing the staple fibers of this invention involves the application of both compressive and shear forces transversely of a bundle of continuous filamentary material which is in a somewhat softened or plastic condition. The bundle of filamentary material may have any cross-section, such as round, elliptical, or generally rectangular. The application of such combined forces: causes a crowding of the filaments for a considerable distance along the length of the bundle in the neighborhood of the application of the forces. This crowding causes irregular distortions or deformations in the individual filaments which become *set upon subsequent drying of the filamentary material. The resulting staple fiber product which is sheared from the continuous filamentary bundle simultaneously with the application of the compressive forces comprises individual fibers at least some of which have a minor portion of their length in a deformed, that is, an irregularly crimped, barbed, or corrugated condition or having a combination of these characteristics and the remainder of their length in a substantially undeformed condition. The somewhat softened or plastic condition of the continuous filamentary bundle may be obtained by suitable treatment of the filamentary bundle before it is subjected to the compression-cutting. Instead of applying a special softening and plasticizing agent for the particular material, a recently spun continuous filamentary tow coming from the spinning machine in a still plastic condition may be subjected directly to the compression-cutting. For example, a continuous filamentary material obtained from viscose still in a somewhat gelatinou condition as it comes from the preliminary washing baths, or a dry-spun cellulose acetate tow still con taining a small residue of solvent therein, may be directly subjected to the compression-cutting. With such material as regenerated cellulose or cellulose acetate, the softened condition may be obtained merely by application of moisture or steam.

A cutter arrangement capable of imparting the combined compressive and shearing forces is illustrated in Figures 1 and 2 where it is associ ated with a Beria type of staple fiber cutter. As shown, the cutter comprises a rotatable disc 2 3 having the centrally located axial channel 3 com-I municating with the radial channel 4. the filamentary bundle being fed into the rotatable disc by way of the axial channel and being conducted through the radial channel byyirtue of centrifugal force set up by rotation of the disc or by a jet of fluid, such as air or water, directed into the axial channel. Suitable means, not shown, are provided to rotate the disc. A knife I having a leading face 8 is supported so that its '4 For all practical purposes, one may start with a knife presenting a cutter angle as above defined of 90 or of even greater size and allow the cutting edge 1 cooperates with the periphery of the disc to sever the filamentary material extending therefrom upon each revolution thereof.

Referring to Figure 2, the various angular relationships of the cutting device will be defined as follows: I

Angle B, hereinafter called the "back angle," is the angle between the tangent and the back face of the knife.

Angle C,hereinafter called the cutter angle," is the angle between the tangent to the disc and the leading face of the knife. In the claims the line of the tangent to the disc is referred to as the line of shear."

Angle E, hereinafter called the "edge angle," is the angle between the back of the blade and the leading face 6 of the blade.

In accordance with the invention the cutter angle C is preferably less than 90 and falls preferably within a range of about 55 toabout 85. The back angle B may vary from 0 to 30 and the edge angle E makes up the balance of 180. From a practical standpoint, back angle B is areferably made about 23 to 25 and edge angle E would therefore vary from about 61 to 102 depending on the values of cutter angle C and of back angle B desired. The thickness of the leading face 8 of the knife designated t in Figure 2 is preferably-on the order of $6 to it of an inch. Giving the thickness of the leading face dimensions of the order offs-inch and larger makes cutting somewhat more dimcult but has the advantage of increasing the length of the crimped and/or corrugated portion of the fibers.

It will be observed that the cutter angle C. is such that the leading face 6 tends to compress the filaments in the neighborhood of. cutting. While it is not abmlutely essential, it is preferred to bevel, roughen or otherwise blunt the edge '8 which the radial channel makeswith the disc periphery and with which the edge 6 of the knife cooperates to effect cutting. This beveling and roughening has'the effect of assuring the production of crimpiness and/or irregular corrugation on the leading ends of the filamentary tow so that the fibers out upon the next revolution of the disc will have both ends crimped and/or irregularly corrugated. Generally the leading ends show slightly less crimp but both ends terminate in barbs. Fibers having a crimp at only one end are produced by disposing a sharp cutter blade on the opposite side of the cutter disk so that cuts would be made-by a blunt and a sharp blade alternately. Occasionally, bushings are employed within the radial channel of the disc and preknife to become blunt during operation so that it then presents a cutter angle of less than 90 and preferably between about 55 to 85'. Whereas it has heretofore been customary to maintain the knives of a staple cutting machine in a sharpened condition, the discovery upon which my invention is based-makes it desirable to avoid the condition of sharpness as hitherto understood.

' Instead of having the blunt leading face I of the knife extending clear across the width thereof, an ordinary sharp knife may be dulled or blunted along that portion of its width which cooperates with the radial channel to cut the staple fibers. The blunting should be such as to provide a-leading face having a thickness preferably of the order of 36. to r; inch extending at an angle within the range of 55 to 85 specified above for cutter angle C. Where such a dulled or blunted knife is employed, it may be desirable to grind down the remaining sharp width of the blade in order to assure better contact of the dulled portion with the cooperating edge 8 of the annular channel though it is not essential sent the edge against which the knife operates.

In such event, the edge of the bushing corresponding to edge 8 is preferably beveled or roughened or both as in the case shown where no bushing is employed.

A preferred embodiment uses a beveled and roughened operating edge 8 of the radial channel or bushing therein, and a knife having its cutter angle C edge angle E back angle B 25 and the edge thickness t inch.

that absolutely perfect contact nor in fact that even reasonably good contact be made between these cooperating edges since the compressive forces are enhanced by avoiding perfect contact.

The leading face 6 of the blade, instead of being constituted by a relatively fiat surface, as shown, may be rather irregular andmay in fact be constituted of small serrations or undulations, the grooves between which extend generally in the direction of the thickness of the leading face 6.

Although the invention has been specifically described and shown in connection with a Beria type of cutter in which a knife cooperates with a rotating disc as a cooperating shear member, other types of cutters may be employed, such as one comprising, as a cooperating shear member, a fixed table across which a bundle of filamentary material is passed and a knife reciprocabie or otherwise swingable with respect to a cutting edge of the table and having a leading face for cooperation therewith set at an angle corresponding to that of cutter angle C of Figure 2. In such embodiments, the companion cutting edge of the fixed table is preferably beveled or roughened or both in a manner similar to that of the edge 8 of the annular. channel in the disc as shown in Figures 1 and 2.

The cutting operation described above may impart the above-described irregularities to but a small proportion of the fibers produced at each cut or to a'much larger part thereof and, if desired, even to substantially all of them, depending upon such conditions as the volume of the filamentary bundle being cut, and the extent of plasticity of the filaments in the bundle. However, the employment of blunt knives in the manner hereinabove described assures that at least some portion of the fibers will have the desired irregularity along one or both of their ends regardless of the volume or extent of plasticity of the filamentary bundle. The character of the irregularity may be varied by variation of the several factors. For example, by operating upon filaments in a softer condition, the fibers produced show an increase in the microscopic corrugations and more pronounced barb-like projections. On the other hand, by operating upon filaments which are completely set up so that they are subject to little or no plastic flow, the fiber product shows few or no fibers having the corrugated or barbed condition, the crimped condition being almost exclusively present instead. By mixing filaments in a somewhat plastic condition with others completely set up, it is possible to obtain cut fibers comprising some that are only crimped and others which exhibit the microscopic corrugations.

Fibers of the present invention as illustrated in Figure 3 which have the microscopic corrugations or a barbed condition superimposed on the crimping show improved spinning capabilities and particularly an enhanced cohesiveness as.

compared with those having only a crimpiness or only the corrugated or barbed condition. It is to be understood that my invention contemplates a fiber product comprising any proportion of fibers one or both of whose ends have been crimped, and/or corrugated whether produced directly by the cutting procedures herein disclosed or whether obtained by mixing a portion of a fiber product so obtained with any proportion of one or more staple flber products produced by other procedures. It also contemplates applying the novel cutting operation to bundles of crimped as well as to uncrimped continuous filaments and also to bundles of filaments in a condition such that after cutting they set up to a crimped condition along their entire length.

While preferred embodiments have been disclosed, the description is intended to be illustrative only, and it is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims.

claim:

1. A staple fiber product comprising artificial organic fibers having a relatively undeformed portion of substantially constant denier constituting the main body of the fibers extending the major portion of their length and having a plurality of deformations along a minor portion of their length adjacent at least one end thereof,

thereby imparting coherence to the product, said deformations comprising microscopic corrugations extending at least partially around the fiber.

2. A staple fiber product comprising artificial organic fibers having a relatively undeformed portion of substantially constant denier consti- Lil) tuting the main body of the fibers extending the major portion of their length and having a plurality of deformations along a minor portion of their length adjacent both ends thereof, thereby imparting coherence to the product, said deformations comprising microscopic corrugations extending at least partially around the fiber.

3. The product of claim 1 in which the artificial fibers referred to comprise regenerated cellulose.

4. The product of claim 2 in which the artificial fibers referred to comprise regenerated cellulose.

5. The product of claim 1 in which the deformations comprise also irregular crimps.

6. The product of claim 2 in which the deformations comprise also irregular crimps.

'7. The product of claim 1 in which the undeformed portion contains an inherent crimp.

8. The product of claim 1 in which the unde- Iormed portion contains an inherent crimp and the deformations comprise also irregular crimps.

NORMAN S. WELTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,723,998 Beria Aug. 13, 1929 2,173,789 Nikles Sept. 19, 1939 2,217,766 Neff Oct. 15, 1940 2,221,716 Morton Nov. 12, 1940 2,266,907 Riehl Dec. 23, 1941 2,278,662 Lodge Apr. 7, 1942 2,370,112 Truitt Feb. 20, 1945 2,407,108 Spalding Sept. 3, 1946 2,418,125 Koster -1 Apr. 1, 1947 FOREIGN PATENTS Number Country Date 319,280 Germany Sept. 19, 1939 367,835 Great Britain Feb. 25, 1932 457,022 Great Britain Nov. 19, 1936 482,976 Great Britain M Apr. 8, 1938 OTHER REFERENCES The Textile Fibers by J. Merritt Matthews, Fourth edition, published 1924, by John Wiley, page -96.

Claims (1)

1. A STAPLE FIBER PRODUCT COMPRISING ARTIFICIAL ORGANIC FIBERS HAVING A RELATIVELY UNDEFORMED PORTION OF SUBSTANTIALLY CONSTANT DENIER CONSTITUTING THE MAIN BODY OF THE FIBERS EXTENDING THE MAJOR PORTION OF THEIR LENGTH AND HAVING A PLURALITY OF DEFORMATIONS ALONG A MINOR PORTION OF THEIR LENGTH ADJACENT AT LEAST ONE END THEREOF, THEREBY IMPARTING COHERENCE TO THE PRODUCT, SAID DEFORMATIONS COMPRISING MICROSCOPIC CORRUGATIONS EXTENDING AT LEAST PARTIALLY AROUND THE FIBER.

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