US2669766A - Crepe fabric - Google Patents

Description

Feb. 23, 1954 R. L, BEA D 2,669,766

CREPE FABRIC Filed June 5, 1947 ROBERT L BEARD INVEN'I'OK Patented Feb. 23, 1954 accrues CREPE FABRIC Robert L. Beard, Kingsport, Tenn., assignor to Eastman Kodak Company, Rochester, N. Y a corporation of New Jersey Application June 5, 1947, Serial No. 752,853

(Cl. ze 'm 4 Claims.

This invention relates to cellulose acetate crepe fabrics and more particularly to an entirely novel all acetate type of crepe fabric having high filling strength and stretch and a substantially permanent pebble possessin an unusually high degree of resistance to embossing and the effects of dye baths, repeated washings and the like.

.In the production of crepe fabric at least one of the yarns entering into the fabric construction, either warp or filling, must be twisted and otherwise treated in such a manner that when the fabric is boiled oif the torsional energy stored in the yarn during the twisting operation can be released and cause the yarn to foreshorten, thus creating a crinkled or uneven surface eliect known as pebble. The conventional method is to crepe-twist only the filling yarns, the twist being inserted generally simultaneously with the application of an aqueous gelatin size which, on evaporation of its water content, solidifies and sets the twist. This temporarily locks the torsional energy of twist in the yarn so that it will not tend to kink or untwist during the weaving operation. The sized yarn is then woven into one of the standard crepe constructions, for example, Canton, matelasse, or the like, and the greige goods thus produced, embossed, boiled off by immersion in a hot soap solution, or other suitable boil-off bath, and then dyed. The boil-off treatment removes the gelatin size, releases the torsional energy originally stored in the yarn and causes it to foreshorten, like a stretched spring released from tension, thus giving rise to the aforementioned pebble effect. It will be readily understood that the whole success of the crepeing process depends, not only upon the ability of the fabric to take a good pebble originally, but especially upon its ability to retain it, during subsequent processing steps such as dyeing, washing and the like.

' As is well known, the technical and patent literature of the rayon industry contains numerous references to the manufacture from cellulose acetate of crepe fabrics. In certain isolated instances attempts have been made to employ cellulose ace tate commercially in the manufacture of such fabrics, either as warp or filling, in order to obtain the improved draping properties known to be contributed by the inclusion of yarns of this material. In general, most of such attempts have been limited to its use as warn, the filling yarn consisting of viscose or natural silk. employment of different types of yarns in the same fabric has, however, provide unsatisfactory, since such a fabric cannot be easily dyed because of the fact that most of the dyes adapted for dye- With the idea of overcoming the difficulties inherent in the use of two different types of yarn, it has for many years been the dream of various rayon manufacturers to produce an all acetate type of crepe fabric, thus eliminating many of the difliculties encountered in dyeing and other wise processing the finished material. In spite of the fact that there have appeared in both the technical and patent literature literally hundreds of proposals for the manufacture from cellulose acetate and other cellulose derivatives of crepe yarns and fabrics, the fact remains that up to the advent of the present invention no manufacturer in the United States or elsewhere, to the best of my knowledge and belief, has ever proposed a practical method for making, nor put on the market, a commercially acceptable all acetate crepe fabric which would have the required tensile strength and stretch and a sufficiently permanent degree of pebble successfully to withstand the effects of embossing and boil-off operations, dyeing, repeated washings and the like, or to compare favorably with crepe produced from natural silk.

Each and every one of the proposals thus far made has been based upon the idea of crepetwisting cellulose acetate yarns produced under ordinary spinning conditions and without reference to certain fundamentally important physical characteristics of the original material which, as will be shown, are of absolutely vital and critical importance if a satisfactory crepe yarn and fabric are to be produced. More specifically, prior workers in this field have depended exclusively upon giving ordinary cellulose acetate yarn pebble producing properties by some special procedures or treatments in which the crepe-twisting or throwing operation is carried out in the presence of agents such as hot water, steam, plasticizers, oil, special size baths and various other agents designed to produce oneor more particular efiects, such as improved twistability, enhanced log viscose or natural silk do not produce the twist-setting, ready release of torsional energy in the boil-off bath and various others. On the other hand, the fundamental and critical. factors, if one would actually obtain satisfactory and permanent pebble producing properties in a crepe-twisted cellulose acetate yarn, have been completely overlooked.

This invention has as an object to produce a commercially acceptable all acetate crepe fabric. A further object is to produce a crepe fabric in which both the warp and the filling yarns consist of cellulose acetate filaments and in which the filling yarn is of such a nature as to produce in the finished fabric a pebble effect which is, to all intents and purposes, permanent or at least is resistant to an unusual degree to the effects of dye baths and repeated washings. A still further object is to produce an all acetate crepe fabric having, not only a highly permanent de- 3 gree of pebble, but also an unusually high filling strength and stretch, as compared to fabrics produced by prior art methods. Another object is to produce an all acetate crepe fabric having high filling strength and stretch and also capable of being embossed by the procedures usually employed in the production of crepe fabrics, without substantial loss of strength of other undesirable effects. A specific object is to produce an all acetate crepe fabric possessing a substantially permanent pebble, high tensile strength and stretch and susceptible or uniform dyeing by means of the usual cellulose acetate dyes. Other objects will appear hereinafter.

degree of pebble, a substantially high tensile strentgh and stretch and susceptible of beingsat- .isfactorily embossed or otherwise treated by the :usual procedures in the manufacture of crepe fabrics. -I have found that a raw yarn material comprising cellulose acetate yarn, the filaments of which have an initial high elongation and a substantial high tensile strength, is satisfactory. Such a yarn may be produced by extruding a solution of cellulose acetate in a volatile solvent in the form of filaments through orifices of a spinnerette and curing the filaments under conditions of minimum tension.

In-view of the vast amount of research which has been carried on in the search for a satisfactory'all acetate crepe fabric and the vast amount of technical and patent literature which has appeared on the subject, this isa most unusual discovery. Emphasis is also lent to the unusual na-- 'ture of my discovery by the fact, as pointed out above, that in spite of the vast accumulation of knowledge and experience in the manufacture of cellulose acetate rayon yarns, no manufacturer has yet come forward with a satisfactory all acetate crepe fabric.

In the following examples and description I have set forth several of the preferred embodiments of my invention but they are included merely for purposesof illustration and not as a limitation thereof.

The single figure of the drawing is a diagrammatic illustration, in partial section, of one form 'of device which may be employed for producing a crepe-twisted cellulose acetate yarn suitable for use in the production of crepe fabrics in accordance with my invention.

Example The first step in producing all acetate crepe fabrics in accordance with .rny invention is to produce a cellulose acetate yarn having a high degree of initial elongation or stretch and a substantial or high tensile strength. As previously indicated, such yarn may be produced by extruding a solution of cellulose acetate in a volatile solvent in the form of filaments through the orifices of a spinneret and curing the filaments under such conditions that a minimum of tension or draft is applied thereto during the curing phase. By minimum of tension or draft is meant a positive but controlled draft'of less than unity and preferably within the range of .4 .to .7 (ratio of linear speed of wind up to linear speed of extrusion of the spinning solution at thespin ning orifices). This'minimum tension is applied to the filaments during their progress through the spinning cabinet. The finished yarns or filaments produced by such a process will have a tensile strength of the order of 1.3 grams per denier and an elongation of the order of 40%- 5-0%. As indicated above, I have found that only by employing as filling a yarn of this type, that is, a yarn having an unusually high degree of initial elongation and at least substantial or high initial tensile strength, can one eventually obtain a crepe fabric having the required physical properties, that is, a substantially permament pebble, satisfactory filling strength and stretch and capable of being satisfactorily embossed, dyed, washed and otherwise processed. The next step in accordance with my invention is to crepe-twist this high strength, .high elongation type cellulose acetate yarn. This oneration-may be carried out, for example, by employing either an up-draft or a down-draft twister and inserting in'the yarn a sufficient twist to give the desired pebble effect. In general, I find it satisfactory to insert a rather high twist in the yarn, say a twist of the order of at least about 75 turns per inch as, with this particular type of yarn, this is found to give the most acceptable degree of pebble in the finished fabric. During or after the insertion of the twist, the yarn is preferably treated by application of a twist setting bath, such, for example, as an aqueous solution of gelatin which may, if desired, contain a good throwing oil or penetrant. Among suitable oils are sulfated vegetable or animal oils, such as sulfated olive, caster, peanut, rice bran, teaseed, neats foot and sperm oils. A satisfactory bath may have the following composition:

Parts by weight Gelatin 1 Sulfated olive oil 5 Water It is my belief that the sole function of the throwing solution is to render the yarn somewhat plastic at the time twisting takes place and thereby to facilitate crepe-twisting. Therefore, almost any aqueous solution which penetrates and wets the fibers and has no adverse effect on the yarn will serve the purpose of the present invention. Gelatin may be omitted entirely from the formula without affecting the physical prop erties or the creping power of the yarn. However, the use of gelatin serves toset the twist and make subsequent processing less diflicult for the reasons previously indicated.

If the twist is inserted in the yarn bymeans of a down-draft twister, an apparatus .such as shown in the accompanying drawing may beemployed. This apparatus may take the form of a frame I to which is bolted-a bracketZ. This bracket is provided with a projection 3 which carries an open bearing 4 to receive the {shaft of a feed roll 5. Bracket 2 is also provided with projection 5 which carries bearing way i which slidingly accommodates the shaft of roll 8. Frame l is also provided, as shown, with a yarn guide 9 through which the yarn I 0 passes from a suitable supply, such as a cone (not shown), into contact with upper feed roll 8 which, in turn, carries it into contact with roll and thence'over guide roll ll suitably mounted in bearings (not shown). After passing over roll H the yarn passes around guide l2 which is submerged to a substantial depth in setting or size bath Hi contained in trough Hi. Upon emerging from the setting bath the yarn passesover guide l5 mounted on bracket I 6,which may beconvenientlyattached to frame I, thence through guide H to a 5 twisting device which may take the form of a spindle driven bobbin provided with a ring type wind-up.

Referring now to a specific example of the production of a crepe-fabric in accordance with my invention, a 150 denier, 38 filament high strength,

high elongation cellulose acetate yarn (tensile strength, 1.3 grams per denier, elongation, 50%) is produced as previously described. This yarn is crepe-twisted to 75 turns per inch in a bath of the above indicated composition employing an apparatus such as shown in the drawing and operated in such manner as to permit the twist to run back into the bath.

The temperature of the bath may be maintained at any convenient level. Temperatures above 30 C. tend to increase the plasticity of the yarn and make it possible to obtain higher twist without excessive end breakage. However, the difficulty of controlling the temperature and maintaining the stability of the solution at elevated temperatures makes it desirable to operate at somewhat lower temperatures, the preferredlevel being approximately room temperature. I have found, for example, that suiii cient plasticizing effect is obtained at about 25 C. to insure efficient operation at the twist re quired to produce the proper pebble in the fabric. I also have found that variation in temperature in the range of 25 to 30 C. has little or no effect I on the properties of the yarn, and, if the solution is maintained at normal room temperature, no control is required.

The path of the yarn through the throwingsolution must be such that the yarn is immersed for sumcient time to permit a complete penetration and wetting of the fibers. The length of immersion should be at least 2 inches and preferably about 6 inches.

For best operation a substantial proportion of the twist should be inserted while the yarn is in the throwing solution, so that excessive amounts of fluid will not be removed from the bath and thrown off the strand onto the machine. The

twist tends to squeeze out any excess of solution .1

(3.2 gram per denier, but prefer to maintain a tension of 0.05 to 0.1 gram per denier. It is im' portant that the tension be maintained relatively constant to prevent variations in contraction.

In the present example, I have referred to the use of ring twisters. However, any type of suit able crepe twisting equipment may be employed.

The finished twisted yarn produced as above described is woven as filling into a standard crepe construction such as a Canton crepe, 140 x 60, with a 100 denier all acetate warp. The resulting fabric is embossed with a fine tree-bark pattern and boiled off in a boil-off bath of-the following composition:

Per cent by weight Neutral olive oil soap /2- /4 Sulfonated fatty alcoholate Fly-V2 Wetting agent 3%; Water Balance The fabric exhibits an'excellent crepe effect or pebble and has a filling grab strength of 28 pounds and a filling grab stretch of 45%. Weaving efficiency is excellent, the fabric dyes satisfactorily and retains its pebble even after repeated washings.

It will, of course, be evident that many modie fications of the above described procedures for producing crepe yarns and fabrics. are possible within the scope of my invention. These modifications to a large degree depend upon the particular properties desired in the finished fabric and it is to be assumed that the throwster and weaver will make such adjustments in the speed of twist, turns inserted, tension, shuttlethreadup and various other details as will produce such properties. Obviously, no hard and fast rules can be laid down as to such matters, since variations will occur with every different crepe fabric construction and with every different denier of yarn. However, it may be said that regardless of these variations, cellulose acetate crepe fabrics produced in accordance with my invention are in every case superior in filling strength and stretch and in permanence of pebble to the nearest com-; parable acetate fabrics produced from ordinary yarns. This is clearly shown in the following discussion of a series of extensive tests in which the various physical properties of crepes produced in accordance with my invention were di rectly compared with crepes produced from regu-1 lar cellulose acetate yarns, that is, yarns spun under high draft conditions and therefore having lower stretch and strength characteristics than the yarns employed in my novel fabrics.

These tests were carried out with three primary objects in view, (1) to compare the filling grab strengths of fabrics woven from the two differ ent types of yarn and having the same degree of pebble, (2) to compare the weaving efficiency in fabrics produced from the two types of yarn and having the same degree of pebble and (3) to compare the degree of pebble in fabrics woven from the two types of yarn and having the same filling grab strengths.

In each of these tests, the two types of yarns employed, that is, ordinary cellulose acetate yarn produced under high draft conditions and yarn produced under low draft conditions (the latter having high elongation and strength) I were crepe-twisted in baths of identical composition, the yarns were woven into fabrics of identical crepe construction, were boiled oif in identical boil-off baths, were embossed with the same type of embossing roll and otherwise finished under the same conditions.

The physical properties'of the two types of yarns are indicated in the following tabulation:

Yarns T pe yarn R egular g g g The yarns in each case were crepe-twisted in a bath having the following compositions:

Parts by weight Sulfated fatty triglyceride 5 Gelatin .1. Water 10,0

permanence of its pebble. mentsit has been found that my new fabrics carried to: a point: sumcient to produce in the finishedfabric the'same degree of pebble and that the number of turns required was somewhat lower in the case of the regular .yarn. than for the highselongation yarn.

Referring to the first test mentioned above, that is, a comparison of the respective filling grab strengths of fabrics woven from the two types of yarn, and having the same degree of :It will be noted from these figures that the filling grab-strength of the fabric (greige goods) produced from high elongation yarn is 28 pounds compared to only pounds for the fabric produced from regular yarn, an improvement of some Likewise, the filling grab strength .of the finished fabric is 28 pounds in the case of the high elongation material as compared to only 18 pounds for theregular material, an improvement of approximately Similarly the filling grab stretch (both greige goods and finished fabric) of the high elongation material is 45% as compared to only 20% for the regular. This is amost unusual and unexpected improvement in physical properties Referring to the-second comparison, that is, between the weaving efliciency for fabrics of equal pebble, a 20 pound sample of each type of yarn was woven into the same crepe construction at the'same mill and on the same looms, one half of each sample being woven alternately on each of two looms. Weaving of the fabric from the high elongation yarn resulted in only 06 break per loom hour, while with regular yarn there were 1.3 breaks per loom hour,'thus clearly establishing the fact that the weaving efficiency of the high elongationmaterial was betteryby over 100% than that of the regular ma terial.

Referring to the third comparison, that is, between the degree 'or amount of pebble in fabrics produced from the two types of yarns having the same or comparable filling grab strengths, fabrics from the two types of yarn were woven and processed under identical conditions. It was found that when the regular. yarnwas "so twisted as to produce in the fabric a comparable filling grab strength to that of a similar fabric produced from high elongation material the fabric had substantially no pebble, thus proving the impossibility of producing from regular yarn fabrics having both good pebble and filling grab strength.

In addition to the marked improvement in physical properties of fabrics produced in accordance with my invention, as shown by the above data, over those of prior art fabrics, one of the outstanding features of my material which sets it apart from all other acetate crepes is the In extensive experi have an ability to withstand embossing withoutsubstantial loss of strength which is greatly superior to that of similar fabrics produced from regular cellulose acetate yarns. In other words, the strength of my novel fabrics is not reduced in this rather drastic treatment nearly to the extent that it is in other acetateor viscose crepes similarly treated. It has also been shown that the pebble of my fabrics is'substantially unaffected by repeated washings, whereas similar acetate or viscose crepes of theprior art lose practically all of their pebble'under such treatment.

From the above described tests it will be evident that I have provided a most unusual and valuable all acetate crepe fabric in every respect outstandingly superior to the nearest comparable prior art crepes. The provision of such a fabric thus constitutes a major contribution to the textile art.

It will of course be understood that the term cellulose acetate as used herein and in the claims is not intended to be limited to cellulose esters'in which the only acyl group present is acetyl but also to include cellulose acetates containing in addition to acetyl a few per cent of another 'acyl group or groups such as propionyl or butyryl'.

What I claim is:

1. A process for producing an all acetate crepe fabric, which new fabric exhibits improvement in that the finished fabric has a filling grab strength of the order of 28 lbs., a filling grab stretch of the order of 45%, and retains its pebble after repeated washings, which include the steps of first obtaining an acetate fillingyarn which is capable of taking a high twist without substantial injury thereto, said yarn being produced by extruding a solution of cellulose acetate in a volatile solvent through at least 38 orificesof a spinneret at a temperature of 80-100 C. to form said filling yarn, said yarn being cured and wound up at a draft of .4 to .7, then crepe twisting this uncoated filling yarn produced as aforementioned to the order of at least 75 turns per inch and at a temperature between 25-30 0., and in carrying out said twisting applying an aqueous setting bath'containing at least one of the components from the group consisting of gelatin and sulphated vegetable oil to set the twist, said twist being applied in a manner where'-- by the twist runs back into said bath, controlling the tension on the yarn while in contact with the bath, so that the tensionis within the range of 0.05 to 0.1 gram per denier, and thereafter weaving the yarn as a filling yarn into an acetate warp, embossing the resultant fabric and subjecting the embossed fabric to a boil off whereby the new all acetate crepe fabric having 1 the steps of first obtaining an acetatefilling yarn which is capable of taking a high twist without substantial injury thereto, said yarn being produced by extruding a solution of cellulose acetate in a volatile solvent through a spinneret at a temperature of -400 C. to form said filling yarn, said yarn being cured and wound-upzat a draft substantially below.l, crepe twisting this filling yarn produced as aforementioned to the order of at least 75 turns per inch, and in carry-- ing out said twisting applying 'a setting bath. said twist being applied in a manner whereby the twist runs back into said bath, controlling the tension on the yarn while in contact with the bath, so that the tension is less than 0.2 grams per denier, thereafter weaving the yarn as a filling yarn into an acetate warp, embossing the resultant fabric and subjecting the embossed fabric to a boil off whereby the new all acetate crepe fabric having the improved characteristics referred to above is obtained.

3. In a process of producing an acetate crepe fabric, which new fabric exhibits improvement in that it has a high filling grab strength, high filling grab stretch and retains its pebble after repeated washings, which includes the steps of first obtaining an acetate filling yarn which is capable of taking a high twist without substantial injury thereto, said yarn having been produced by extruding a solution of cellulose acetate in a volatile solvent through a spinneret at a temperature of 80-100 C. to form said filling yarn, and followed by curing and winding up said filling yarn at a draft of .4 to .7, crepe twisting this uncoatecl filling yarn produced as aforementioned to the order of at least 75 turns per inch, and in carrying out said high twisting applying a setting bath to set the twist, controlling the tension on the yarn while in contact with the bath, so that the tension is less than .2 gram per denier, thereafter weaving the yarn as a filling yarn into an acetate warp, embossing the resultant fabric and subjecting the embossed fabric to a boil off whereby the new acetate crepe 10 fabric having the improved characteristics referred to above is obtained.

4. A fabric having high strength and elongation and capable of being embossed for creping to produce a crepe fabric highly resistant to a loss of pebble due to repeated washings, said fabric being characterized in that it contains a major amount as an essential component of a very high elongation acetate yarn, which yam has a tensile strength on the dry basis of at least 1.3 grams per denier and elongation of the order of and a twist of at least turns per inch.

ROBERT L. BEARD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,986,755 Banfield Jan. 1, 1935 2,058,421 Dickie et a1. Oct. 27, 1936 2,058,427 Dreyfus et a1. Oct. 27, 1936 2,067,816 Barnick Jan. 12, 1937 2,086,719 Lardy July 13, 1937 2,094,781 Dreyfus Oct, 5, 1937 2,169,269 McNally Aug. 15, 1939 2,366,278 Mehler Jan. 2, 1945 2,445,751 Thomas July 27, 1948 2,522,225 Helwith Sept. 12, 1950 FOREIGN PATENTS Number Country Date Great Britain Dec. 19, 1924

Claims (1)

1. A PROCESS FOR PRODUCING AN ALL ACETATE CREPE FABRIC, WHICH NEW FABRIC EXHIBITS IMPROVEMENT IN THAT THE FINISHED FABRIC HAS A FILLING GRAB STRENGTH OF THE ORDER OF 28 LBS., A FILLING GRAB STRETCH OF THE ORDER OF 45%, AND RETAINS ITS PEBBLE AFTER REPEATED WASHINGS, WHICH INCLUDE THE STEPS OF FIRST OBTAINING AN ACETATE FILLING YARN WHICH IS CAPABLE OF TAKING A HIGH TWIST WITHOUT SUBSTANTIAL INJURY THERETO, SAID YARN BEING PRODUCED BY EXTRUDING A SOLUTION OF CELLULOSE ACETATE IN A VOLATILE SOLVENT THROUGH AT LEAST 38 ORIFICES OF A SPINNERET AT A TEMPERATURE OF 80-100* C. TO FORM SAID FILLING YARN, SAID YARN BEING CURED AND WOUND UP AT A DRAFT OF .4 TO .7, THEN CREPE TWISTING THIS UNCOATED FILLING YARN PRODUCED AS AFOREMENTIONED TO THE ORDER OF AT LEAST 75 TURNS PER INCH AT A TEMPERATURE BETWEEN 25-30* C., AND IN CARRYING OUT SAID TWISTING APPLYING AN AQUEOUS SETTING BATH CONTAINING AT LEAST ONE OF THE COMPONENTS FROM THE GROUP CONSISTING OF GELATIN AND SULPHATED VEGETABLE OIL TO SET THE TWIST, SAID TWIST BEING APPLIED IN A MANNER WHEREBY THE TWIST RUNS BACK INTO SAID BATH, CONTROLLING THE TENSION ON THE YARN WHILE IN CONTACT WITH THE BATH, SO THAT THE TENSION IS WITHIN THE RANGE OF 0.05 TO 0.1 GRAM PER DENIER, AND THEREAFTER WEAVING THE YARN AS A FILLING YARN INTO AN ACETATE WARP, EMBOSSING THE RESULTANT FABRIC AND SUBJECTING THE EMBOSSED FABRIC TO A BOIL OFF WHEREBY THE NEW ALL ACETATE CREPE FABRIC HAVING THE IMPROVED CHARACTERISTICS REFERRED TO ABOVE IS OBTAINED.

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