US2282568A - Cellulosic structure and method for preparing same - Google Patents

Description

May 12, 1942- T. G. FINZE'L 2,282,568

' CELLULOSIC STRUCTURE AND METHOD FOR PREPARING SAME Filed Oct. 5,' 1938 7582022 6. 77225 INVENTOIL .IAT-TORNEY Patented May 12, 1942 CELLULOSIC STRUCTURE AND METHOD FOR PREPARING SAME Theron G. Finzel, Kenmore, N. Y., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware Application October 5, 1938, Serial No. 233,484

26 Claims.

This invention relates to artificial fibers, filaments or the like and yarns, threads, cords or the like composed of artificial fibers and filaments, and methods for producing same. More particularly, it relates to threads, yarns, cords or the like composed of artificial fibers, filaments, or the like having a unique, random crimp and improved methods for producing such structures. The invention is particularly applicable and has exceptional utility in the formation of curls and crimps in thermoplastic cellulosic filaments and yarns.

It has been recognized for some time that the Warmth of wool is due mainly to the air spaces entrapped between adjacent fibers and also due to the ability of these fibers to maintain such air spaces even after the fabrics composed thereof have been subjected to water-wetting and/or mechanical forces. The ability of wool in this regard is largely traceable to the decided crimp inherently present in wool, particularly of the finer high grade types. In contrast yarns, composed of artificial fibers or filaments such as cellulose acetate rayon, viscose rayon, or cuprammonium rayon, by virtue of the fact that they normally are spun under tension, are silk-like and possess straight filaments which are devoid of any crimp or curl.- Accordingly, it has been reasoned logically that in order to impart a woollike warmth characteristic to artificial fibers, it would be necessary to insert a curl or crimp in the same.

Numerous methods for imparting curls or crimps to yarns composed of artificial filaments have lzcen proposed prior to this invention. However, great difiiculty has attended the impartation of a curl or crimp which will be substantially permanently retained by the filaments without objectionably degrading the same. Prior methods for crimping or curling yarns and filaments have failed due to the impartation of the curls and crimps in a state of stress and strain and consequently an abnormal or unstable condition. Under such conditions, of course, the permanency of the crimp is not altogether satisfactory, since naturally the crimped yarn tends to revert to a normal straight yarn in order to relieve the stress and strain.

An object of this invention is to provide a crimped yarn composed of crimped artificial filaments or fibers in which the crimped condition represents essentially the natural or normal state, free from stress and strain, so that change of such kink or crimp to a straight condition represents to a certain extent a condition of stress and strain.

Another object is to provide a yarn composed of crimped, artificial filaments in which the crimp is relatively more permanent and less easily removed than a crimp imparted by mechanical means.

A further object is to provide a yarn composed of crimped, artificial filaments character- I textile fabrics, particularly of the pile fabric type,

that possess an increased fullness. v

A still further object is to provide the crimped yarn of the invention in the form of a contin-' uous filament yarn.

A specific object is to provide a thermoplastic, cellulosic yarn having the permanency and type of crimp described in the above objectives.

A more specific object of the invention is to provide a relatively effective and economical procedure of accomplishing the above objects.

Other objects of the invention will appear hereinafter.

The crimped yarn of the invention is prepared by a process comprising impregnating a yarn composed of artificial fibers or filaments with a substance capable of vaporizing rapidly when heated to a suitable temperature below the melting point of the yarn, suddenly contacting the impregnated yarn, while maintaining the same free from tension and thus permitting it to shrink freely, into a hot bath consisting of a liquid nonsolvent for the yarn and thereby removing rapidly substantially all the vaporizable substance from the yarn whereby a crimp is simultaneously imparted to the filaments which crimp is also exhibited by the yarn.

The invention will be more clearly apparent by reference to the following detailed description taken in connection with the accompanying illustrations, in which;

Figure 1 is a diagrammatic illustration of one form of apparatus adapted to carry out the process of this invention. I

Figure 2 is a highly magnified view showing a yarn which has been subjected to the crimping process of this invention.

In the illustrations reference numeral 5 designates a cake of yarn composed of artificial filaments which has been impregnated or conditioned with a vaporizable liquid in a. manner hereinafter to be described. The yarn 6 is removed from the bobbin 5 by means of positively driven feed rolls 1, 8, and. 9. The thread passes from the feed rolls into a tank containing a liquid high boiling non-solvent for the yarns. The liquid is maintained at a temperature below the melting point of the yarn but at least 30 above the boiling point of the vaporizable liquid with which the yarn has been treated. The yarn 6 is removed from the tank In by means of positively driven feed rolls ll, l2, and I3. The yarn, 'during its contact with the hot liquid is maintained free from any tension so as to permit free shrinkage of the yarn.

A large number of deep, irregular crimps projecting in all directions is imparted to the filaments of the yarn. The speed of feed rolls 1, 8, and 9 and the speed of feed rolls H, l2,

and I3 may be so adjusted as to continuously maintain a section of the yarn in free coils within the hot liquid. The yarn is passed from feed rolls II, I2, and I3 into a collecting can I 4 or the like where it is collected in loose coils without imparting tension thereto.

After the yarn 6 has been subject to the abovedescribed crimping operation, the filaments 6a will exhibit individual crimps which are out of phase with each other as shown in Figure 2.

In the preferred embodiment of the invention a substantially untwisted thermoplastic cellulosic yarn composed of a plurality of filaments is treated so as to give the filaments deep, random, and irregular crimps that represent a normal, stable condition. This may be accomplished in the following manner. The thermoplastic yarn is impregnated or conditioned with a vaporizable liquid having an atmopheric boiling point at least 30 C. lower than the temperature of the hot crimping bath. In the case of a relatively water-soluble vaporizable liquid, including water, the thermoplastic yarn is conditioned in contact with the saturated vapors thereof until the yarn has sorbed an amount equal to but not exceeding "a saturated equilibrium sorption condition at the temperature of the yarn immediately prior to introduction into the hot crimping bath. In the case of a relatively water-insoluble but oil-soluble vaporizable liquid, such as heptane, the yarn is conditioned in contact either with the saturated vapor and/or with the liquid. The conditioned yarn is introduced quickly, while maintaining it free from tension and free to shrink, into a hot liquid crimping bath comprising a high boiling nonsolvent for the yarn. The bath should have a temperature somewhat below the melting point of the yarn and at least 30 C. above the boiling point of the vaporizable liquid employed to condition the yarn. In the case of a continuous yarn, the rate at which the yarn is fed into the crimping bath may be 5% to 60% faster than the rate the yarn is withdrawn. Upon introduction into the crimping bath, the yarn immediately softens somewhat, and the vapor formed in situ from the vaporizable liquid is emitted steadily and rapidly as small bubbles at random from and/or through certain parts of the yarn surface. During emission of the -vapors the yarn and the constituent filaments in the filaments after insertion of the crimp is removed by permitting the yarn to remain in the crimping bath for a very short time after the vapors have apparently all been driven from the yarn. The total time during which the yarn is permitted to remain in the crimping bath may vary widely depending upon the chemical composition of the yarn, the composition and method of the vaporizable substance with which the yarn is treated, the composition and temperature of the crimping bath, and possibly for other reasons. As a general rule,- however, the total time of contact with the crimping bath should be not substantially less than of a second and not more than 180 seconds. The crimped yarn is removed undersub'stantially no tension from the crimping bath. The yarn is allowed to cool in a relaxed condition to room temperature in order to set the crimp to a condition that the crimped form is a normal stable one, substantially free from stress and strain.

The following examples illustrate certain specific applications of the invention, it being understood, of course, that they are not to be construed as being restrictive of the scope of the invention:

Example I Untwisted, 10 denier per filament cellulose acetate yarn having a combined acetic acid content of about 54% is conditioned several days at room temperature in an atmosphere of high relative humidity (65% to R. H.) until no further gain in moisture content is observed. The conditioned yarn is entered quickly but loosely into a light mineral oil bath which is held at a temperature between C. and 220 C. Upon entrance into the oil bath, the yarn becomes softened and somewhat plastic and the moisture in and on the yarn is rapidly vaporized. The rapid and steady issuance of vapor at random from the surface of the yarn causes the filaments to warp and bend irregularly and a crimp results. After the moisture has been entirely driven from the yarn, the crimped yarn in its plastic condition is maintained in contact with the hot bath for a second or so longer in order to relieve all internal strains. In order to maintain the yarn in a loose condition in the oil bath, the feed rate of yarn into the bath is 10% to 25% greater than the rate of yarn take-off from the bath and in order to have suflicient time for driving off all the moisture and for heating the yarn slightly thereafter, the length of the bath is such as to give a yarn contact with the bath of approximately 2 to 3 seconds. After withdrawal from the bath, the yarn is allowed to cool in order to set the crimp. If desired, the oil is extracted from the yarn with suitable liquids such as toluene, trichlorethylene, or other dry cleaning agents. The oil may also be removed by scouring the yarn with of Gardinol or soap solution at 75 C. to 85 C. After rinsing, the yarn is allowed to air dry. As measured on the dry yarn, the crimp inserted in the filaments by the oil bath amounts to 15 to 30 crimps per inch and not only is irregular as to form-of the crimp, but also is distributed in a random manner along the length of the filaments. The crimped yarn is soft and bulky and has a desirable hand.

Example II Instead of white mineral oil, olive oil heated to to 200 C. may be used in the same manner as disclosed in Example I. If desired, the olive oil remaining on the yarn after the crimping treatment need not be completely removed,

Example III A pile fabric, the pile of which consists largely of cellulose acetate fibers, is conditioned for several days at room temperature in an atmosphere having a humidity of nearly 100% R. H. until no 1 further gain in moisture content is observed. The

thus humidified fabric is immersed for about 2 seconds in a bath of white mineral oil held at a temperature between 180 and 220 C. After removing the fabric from the oil bath and allowing it to cool, the residual oil in the fabric is extracted by means of organic solvents such as toluene or dry cleaning fluid.

By virtue of the oil bath treatment, the fibers of the pile of the treated fabric are crimped and because of their crimped condition support each other to a large extent in an erect position and, in consequence, present more of a brush effect than similar but untreated fabric. also is more full and more crush-resistant than an untreated pile fabric.

Example IV Cellulose acetate staple fibers of, for instance, 5.5 denier or denier per filament are conditioned in a loose and open state over water, at room temperature for several days so as to absorb as much moistureas possible without condensation of free water on the fibers. The moisturecontaining staple fibers in a loose and fiuffy physical condition are immersed for 2 to 4 seconds in a mineral oil bath that is held at .a temperature of 180 to 220 C. The 2 to 4 seconds contact of the fibers with the bath vap'orizes ofi completely the moisture in the fibers and imparts a high degree of crimp. After' withdrawal from the bath, the oil is removed from the staple fibers by centrifuging and subsequent extraction with organic solvents such as toluene or' petroleum type solvents. The resulting crimped fibers possess a desirable appearance and feel.

Example V Example VI Untwisted viscose rayon yarn composed of a plurality of filaments, the filament denier 'of which is approximately 10, is-immersed for several hours in water at room temperature. The wet yarn is passed through a pair of rubber squeeze rolls to remove the excess of water and then is entered rapidly in a hot mineral oil bath, the temperature of which is 190 to 220 C., and preferably 210 C. Substantially all the water in the yarn issues as steam which softens the yarn and warps the individual filaments thereof and yields a deep crimp therein. The length of time of contact of the yarn with the oil bath is The fabric 3 approximately 1 to 3 seconds, which permits the crimp to be inserted and permits also slight afterheating of the yarn to increase the stability of the crimp. After withdrawing the yarn without tension from the oil bath, the yarn is cooled and the oil is removed from the yarn in a manner described previously in the above examples. The resulting oil-free and dry viscose rayon yarn possesses a very definitely crimped condition an has a desirable appearance and hand.

Example VII Untwisted gel viscose rayon yarn composed of a plurality of filaments, having a denier of about 10, which has been regenerated, desulfured, bleached, washed, but never dried, is submerged for 1 to 3 seconds in a mineral oil bath held at a temperature of 180 to 210 C. After withdrawal under no tension from the oil bath, the yarn is cooled and the oil is removed in the usual way.

The resulting yarn is highly crimped and has an appearance similar to that described in Example VI. I

The yarns may be impregnated or conditioned with volatilizable materials of many kinds and the specific selection will depend on factors such as the base material of the particular artificial yarn and the temperature of the crimping bath.

The process will operate if the volatilizable or bath. In the case of liquid volatilizable conditioning agents, it is preferred that the liquid have a boiling point at least about 30 C. below the temperature of the crimping bath, and therefore at least about 30 C. below the melting point of the yarn treated. For instance, inthe case of certain cellulose acetate yarns, it is desirable that the volatilizable liquid have a boiling point below 150, and more preferably under 115 C. In the case of conditioning a thermoplastic yarn, such as cellulose acetate, with a volatilizable liquid such as water, it is preferred that the yarn be impregnated by contact with the vapors of the liquid rather than by direct contact with the liquid. In

the case of water, the cellulose acetate yarn preferably is exposed at the temperature the yarn will have immediately prior to entrance into the crimping bath to an atmosphere of at least 30% R. H., and more preferably to R. H., until the equilibrium amount of moisture has been sorbed by the yarn. The cellulose acetate yarn, however, may be conditioned directly in contact with water, provided all water in excess of the equilibrium amount described in the preceding sentence is removed prior to immersion of the yarn in the crimping bath. In general, cellulose acetate yarn which is conditioned in an atmosphere the relative humidity of which is lower than 95% to 100% can be subjected to a higher temperature in the subsequent oil treatment than those conditioned at 100% R. H. In the case of conditioning liquids of the water-insoluble type,

izable materials which can be used for conditioning cellulose acetate yarn and the results obtained when the yarn is conditioned by contact with the liquid and vapor formof the material. The table also describes the crimping bath temperature ranges which are suitable with each type of conditioning.

' Crimping bath Crimping bath tempcratemperatures for Conditioning agent tures {or yarn condiyarn conditioned tioned in the liquid in vapor over the liquid Isopropyl alcohol..... 115-200 C. (fibers slight- 1l5200 C. (d-

ly wea bers strong). Methyl alcohcl.....-.. l-200 C. (fibers weak). 115-185 C. Carbon tetrachloride. l35-200 C... 135-210 C Toluene l502l0 C- l752l0 C Benzene 150-200 C--. 150-200 C Heptane l652l5 C 165-2l5 C kcrtiii 1sllcilduni. Dissolves yarn l40l75 C U o e y 6110 g Y o 58; ..do 115-210 C. o ace one. o 20% }....d0 170-200 0. Water L 120-140 C 180220 C.

' to prevent condensation of liquid water on the cellulose acetate yarn if it is planned to use a high crimping bath temperature.

The optimum amount of volatilizable material position of the yarn and the crimping bath temperature used in driving out the volatile maaterial. Cellulose acetate can best be conditioned, for example, by allowing it to absorb an equilibrium amount of moisture from an atmosphere of 95% to 100% R. H. at room temperature immediately after which the yarn is immersed in a hot oil crimping bath ata' temperature of 180 to 220 C.

Liquid materials other than mineral oil may be used as the heatin media of the crimping bath. The prime requisites for such a liquid material are that it should be substantially inert to the yarn treated, i. e., it should not swell, dissolve, or attack the yarn treated; it should not be unduly volatile at the temperature of treatment; it should not dissolve the vapor liberated from the yarn to any appreciable extent at the temperature of treatment; and-it should be easily removed from the yarn after the yarn treatment. Accordingly, the choice of the material for the bath will depend largely upon the composition and type of yarn being treated and the temperature to be employed for the crimping. Bearing such factors in mind, the selection may be made from such materials as chlorinated diphenyl,

chlorinated naphthalene, diphenyl, ethyl sebacate, olive oil, corn oil, castor oil, cottonseed oil, mineral oil, and metallic baths such as Woocls metal or mercury.

The temperature of the crimping treatment may vary from approximately 115 C. to 250 C., or even wider, depending upon the kind of volatile material absorbed by the fibers before treatment in the hot bath and also upon the chemical nature of the yarn. In general, it is necessary 2,282,568 liquid. The following table discloses some volatil in the case of thermoplastic yarn that the temperature'oi the crimping bath be somewhat below the melting point of the yarn and at least C. higher than the boi ing point of the volatilizable or vaporizable conditioning material. In the particular case of cellulose acetate yarn, the lower the combined acetic acid content, the higher may the temperature of the crimping bath be, since the melting point of the yarn is somewhat higher and since the yarn may tolerate more moisture. Cellulose acetate yarn-having a combined acetic acid content of 51.2% can be successfully crimped at 240 C.

The manner in which the conditioned yarns are subjected to the hot bath treatment is extremely important. In the crimping bath it is necessary to secure an extremely rapid heat transfer between the heating medium and the yarn in order to produce the vapors in situ and emit the same as small bubbles in a steady, rapid rate, but at random, from thesurface of the yarn. Generally, the conditioned textile yarn is immersed quickly and passed through the hot oil crimping bath while maintained free from any tension and, therefore free to shrink, and withdrawn from the bath under little, if any, tension. In the case of conditioned fibers such as staple lengths, it is important that they be placed loosely in the bath heldby the yarn depends upon the base comand in an open condition, so that they are in a position to shrink and crimp freely. The time of contact with the bath, as above described, is generally about of "a second to seconds. It is desirable to have the yarn in contact with the oil bath for a sufiicient period to insert the desired degree of crimp, but it is undesirable to have the yarn in contact With the bath too long, as such promotes a weakening, embrittlement, discoloration, and charring of the yarn. It is also preferred to maintain the yarn in contact with the crimping bath for a sufiicient period of time to not only drive off substantially all the volatilizable material, but also to after-heat for a very short time to remove any strained condition.

The most desirabl manner of removing the crimping medium, after the treatment, especially if an oil bath is employed, is to extract the oil or oily material with toluene or a petroleum fraction such as dry cleaners liquid, which will dissolve the oil or oily substance and not affect the crimped yarn. Boil-oil methods with soap or Gardinol (sodium salts of higher fatty alcohol sulfates) may be utilized, but the efiiciency of oil contrast to the smooth rayon and silk yarn.

Such rough crimped yarns abraid very easily and tear readily unless properly sized. Any suitable sizing solution which is used in the art for sizing bulky threads to permit their use in textile operations may be employed.

In the above specification, reference has been to cellulose acetate yarn as the thermoplastic artificial yarn. It will, of course, be recognized that the invention may also be applied to secure crimped yarns composed of other thermoplastic maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a sufiiciently elevated temperature to quickly volatilize said volatilizable material, and cause said filaments to crimp while in contact therewith, said volatilizable material having a boiling point at least 30 C. below the temperature of said liquid non-solvent.

4. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises applying to such structures comprising artificial filaments a volatilizable material, and then contacting said structures, -while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a temperature below the melting point of said structures but said temperature being sufficiently elevated to quickly volatilize said volatilizable material and cause said filaments to crimp while in contact therewith, said volatilizable material having a boiling point at least 30 C. below the temperature of said liquid nonsolvent.

5. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without sub stantially weakening the filaments which comprises applying to such structures comprising artificial filaments vapors of a volatilizable material, and then contacting said structures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a sufiiciently'elevated temperature to quickly volatilize said volatilizable material and cause said filaments to crimp while in contact therewith.

6..The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially-weakening the filaments which comprises applying to such structures comprising artificial thermoplastic filaments vapors of a volatilizable material, and then contacting said structures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a sufliciently elevated temperature to quickly volatilize said volatilizable material and cause said filaments to crimp while in contact therewith.

7. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises applying to such structures comprising arcause said filaments to crimp while in contact therewith.

9. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises applying to such structures comprising artificial filaments vapor of a volatilizable material, and then contacting said structures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid havlng a temperature below the melting point ofsaid structures but said temperature being sulficiently elevated to quickly volatilize said volatilizable material and cause said filaments to crimp while in contact therewith.

10. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises applying to such structures comprising artificial filaments vapors of a volatilizable material, and then contacting said structures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a temperature below the melting point of tificial thermoplastic cellulosic filaments vapors of a volatilizable material, and then contacting said structures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a sufiiciently elevated temperature to quickly volatilize said volatilizable material and cause said filaments to crimp while in contact therewith.

8. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, stantially weakening the filaments which comprises applying to such structures comprising cellulose acetate filaments vapors of a volatilizable material, and then contacting said structures, while maintaining the same free from tension,

with a liquid non-solvent for said filaments, said liquid having a sufiiciently elevated temperature to quickly volatilize said volatilizable material and irregular crimps without subsaid structures but said temperature being suf ficiently elevated to quickly volatilize said volatilizable material and cause said filaments to crimp while in contact therewith, said volatilizable material having a boiling point at least 30 C. below the temperature of said liquid nonsolvent.

11. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises subjecting such structures comprising artificial filaments to an atmosphere having a relative humidity of at least 30%, until the moisture content of the structures comes to equilibrium, and then contacting said structures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a sufiiciently elevated temperature to quickly volatilize said moisture content of the structures and cause said filaments to crimp while in contact therewith.

12. The method 'of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular. crimps without substantially weakening the filaments which. comprises subjecting such structures comprising artificial thermoplastic filaments to an atmosphere 7 having a relative humidity of at least 30%, un-

til the moisture content of the structures comes to equilibrium, and then contacting said struc--' tures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a sufliciently elevated temperature to quickly volatilize said moisture content of the structures and cause said filaments to crimp while in contact therewith.

13. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises subjecting such structures comprising artificial thermoplastic cellulosic filaments to an atmosphere having a relative humidity of at least 30%, until the moisture content of the structures comes to equilibrium, and then contacting said structures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, saidliquid having a a very definite and desirable depth "and lofty materials such as cellulose acetate propionates, cellulose" acetate butyrate, and other simple and mixed aliphatic acid esters of cellulose; as well as methyl cellulose, ethyl cellulose, propyl celluose, butyl cellulose, and other organic ethers of cellulose; as well as yarns composed of vinyl acetate resins, vinyl acetal resins, vinyl chloride-vinyl acetate interpolymer resins, and other vinyl resins. Obviously, also the artificial materials to be crimped'may contain within reason plasticizers, pigments, dyes, and other modifiers. Additionally, while perhaps of less interest, the invention may be applied to other cellulosic artificial yarns such as the regenerated cellulose type derived in the viscose and cuprammonium process. Because regenerated cellulos yarn is not therm plastic. certain slight changes may be made in the process of the invention as compared to cellulose acetate yarn. For instance, in the case of regenerated cellulose yarn, the temperatures of the crimping bath can be increased considerably in many cases. Likewise, the specific choice of the volatilizable material may be somewhat different from that for cellulose acetate Yarn. Additionally, the regenerated cellulose yarn in the case of water, can be humidified by exposure to a moist atmosphere or it may be soaked directly in water and the excess liquid water removed by shakin and the yarn crimped in the hot oil bath at a, temperature of 180 to 220 C. All these slight differences, however, are considered to be well within the province of one skilled in the art.

The filament'denier of the cellulose acetate yarn, as well as regenerated cellulose rayon yarn, has a very definite effect on the degree of crimp obtained. It has been found that filaments of heavy denier showed a most pronounced crimp. For instance, the degree of crimp of a 10 denier filament is greater than that of the 5.5 denier which, in turn, is greater than that of a 3 denier filament.

In the above specification any reference to an untwisted yarn is meant to include yarn having a very slight twist, for example, not more than two turns per inch whereby to hold the filaments together, as well as yarn having no twist. The term yarn in the present specification is intended to include yarn of continuous length and composed of individual continuous filaments, or yarn in which some of the filaments have been cut, or yarn cut to form filaments of staple length or other obvious modifications. The term crimp as used in the present specification is meant to include crimps, curls, undulations or other abrupt bends in the filaments and/or yarns.

By means of the present method a decided and accentuated crimp is imparted to the straight hand.

It will be understood that the crimping process I of the present invention may be combined with filaments and at the same time, all strains are relieved and the crimped filaments are set in their new and crimped form in a state in which the crimped form is normal and stable, while the straight condition is abnormal. The crimped yarns are thus put into a condition wherein more force is necessary to pull them out to a straight condition than necessary with filaments curled by mechanical or similar methods. The crimped yarns obtained in accordance with my methods disclosed herein are lofty in appearance and show a greater resistance to crushing than yarns curled by mechanical means. The yarns possess a realtively large number of fine and irregularly placed undulations or crimps per inch of length so that the yarns show good covering power and the fabrics produced therefrom show other methods of crimping to produce crimped filaments, threads, and the like having a composite crimp. Thus, in addition to imparting crimp according to the novel procedure described above, a further crimp can be imparted which may be either of a greater or less degree than the crimp which has been impe rted by the oil crimping procedure. In following this modification, it is preferred that the second crimp be greater in degree, that is, less crimps per inch than the crimps produced by the oil crimping process. The oil crimping process of this invention can be supplemented, for example, by passing the yarn after it has been crimped by the oil crimping process, and preferably before the oil has been removed and while the yarn is still hot, through a crimping device such as is illustrated in Stone et al., Patent No. 1,973,581, issued September 11, 1934. Fabrics produced from yarns crimped in this manner have more fullness and bulk than fabrics composed of yarn which has been subjected only to the oil crimping process. It is understood, of course, that in this modification of the invention, reference to crimping with oil is illustrative and that in place of oil, the other equivalents of oil mentioned in this specification may, of course, be used.

Since it is obvious that many changes and modifications can be made in the above-detailed description without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited except as set forth in the appended claims.

I claim:

1. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises applying to such structures comprising artificial thermoplastic filaments .a volatilizable material, and then contacting said structures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a sufficiently elevated temperature to quickly volatilize said volatilizable material, and cause said filaments to crimp while in contact therewith, said volatilizable material having a boiling point at least 30 C. below the temperature of said liquid non-solvent.

2. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises applying to such structures comprising artificial thermoplastic cellulosic filaments a volatilizable material, and then contacting said structures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a sufiiciently elevated temperature to quickly volatilize said volatilizable material, and cause said filaments to crimp while in contact therewith, said volatilizable material having a boiling point at least 30 C. below the temperature of said liquid non-solvent.

3. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises applying to such structures comprising cellulose acetate filaments a volatilizable material, and then contacting said structures, while sufiiciently elevated temperature to quickly volatilize said moisture content of the structures and .cause said filaments to crimp while in contact therewith.

liquid having asufiiciently elevated temperature to quickly volatilize said moisture content of the structures and cause said filaments to crimp while in contact therewith.

15. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises subjecting such structures comprising artifical filaments to an atmosphere having a relative humidity of at least 30%, until the moisture content of the structures comes to equilibrium, and then contacting said structures, while maintaining the same free from tension, with a liquid non-solvent for said filaments, said liquid having a temperature below the melting point of said structures but said temperature being sufliciently elevated to quickly volatilize said moisture content of said structures and cause said filaments to crimp while in contact therewith.

16. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which com prises subjecting such structures comprising artificial filaments to an atmosphere having a relative humidity of at least 30%, until the moisture content of the structures comes to equilibrium, and then contacting said structures, while maintaining the same'free from tension, with an oil which is substantially inert to said filaments, said oil having a sufliciently elevated temperature to quickly volatilize said moisture content of the structures.

1'7. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises subjecting such structures comprising artificial thermoplastic filaments to an atmosphere having a relative humidity of at least 30%, until the moisture content of the structures comes to equilibrium, and then contacting said structures, while maintaining the same free from tension, with an oil which is substantially inert to said filaments, said oil having a sufficiently elevated temperature to quickly volatilize said moisture content of the structures.

18. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantiallyweakening the filaments which comprises subjecting such structures comprising artificial thermoplastic cellulosic filaments to an atmosphere having a relative humidity of at least 30%, until the moisture content of the structures comes to equilibrium, and then contacting said structures, while maintaining the same free from tension, with an oil which is substantially inert to said filaments, said oil having a sufiiciently' elevated temperature to quickly volatilize said moisture content of the structures.

19. The method of producing threads, yarns, fabrics, and like structures. comprising filaments exhibiting' deep, irregular crimps without substantially weakening the filaments which comprises subjecting such structures comprising cellulose acetate filaments to an atmosphere having a relative humidity of at least 30%, until the moisture content of the structurescomes to equilibrium, and then contacting said structures,

while maintaining the same free from tension, with an oil which is substantially inert to said filaments, said dil having a sufficiently elevated temperature to quickly volatilize said moisture content of the structures.

20. The method of producing threads, yarns,

fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprising subjecting such structures comprising.

artificial filaments to an atmosphere having a relative humidity of at least 30%, until the moisture content of the structures comes to equilibrium, and then contacting said structures, while maintaining the same free from tension, with an oil which is substantially inert to said filaments, said oil having a temperature below the melting point of said structures but said temperature being sufi'iciently elevated to quickly volatilize said moisture content of said structures.

21.'The method of producing threads, yarns,- fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises subjecting such structures comprising artificial filaments to an atmosphere having a relative humidity of between 95% and 100% until the moisture content of the structures comes to equilibrium and then immersing said structures, while maintaining the same free from tension, into a bath of oil which .is substantially inert to said structures, said oil bath having a sufiiciently elevated temperature to quickly volatilize said moisture content of the structures.

22. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises subjecting such structures comprising artificial thermoplastic filaments to an atmosphere having a relative humidity of between 9 and 100% until the moisture content of the structures comes to equilibrium and then iminersing said structures, while maintaining the same free from tension, into a bath of oil which is substantially inert to said structures, said oil bath having a sufiiciently elevated temperature to quickly volatilize said moisture content of the structures.

23. The method. of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without 'substantially weakening the filaments which comprises subjecting such structures comprising artificial thermoplastic cellulosic filaments to an atmosphere having a relative humidity of between and until the moisture content of the structures comes to equilibrium and then immersing said structures, while maintaining the same free from tension, into a bath of oil which is substantially inert to said structures, said oil bath having a sufficiently elevated temperature to quickly volatilize said moisture content of the structures.

24. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps. without substantially weakening the filaments which comprises subjecting such structures comprising, cellulose acetate filaments to an atmosphere having a relative humidity of between 95% and 100% until the moisture content of the structures comes to equilibrium and then immersing said structures, while maintaining the same free from tension, into a bath of oil which is substantially inert to said structures, said oil bath having a sufiiciently elevated temperature to quickly volatilize said moisture content of the structures.

25. 'The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises subjecting such structures comprising artificial filaments to an atmosphere having a relative humidity of between 95% and 100% until the moisture content of the structures comes to equilibrium and then immersing said structures, while maintaining the same free from tension, into a bath of oil which is substantially inert to said structures, said oil-bath having a temperature below the melting point of said structures but said temperature being sufiiciently elevated to quickly volatilize said-moisture content of said structures.

26. The method of producing threads, yarns, fabrics, and like structures comprising filaments exhibiting deep, irregular crimps without substantially weakening the filaments which comprises subjecting such structures comprising artificial filaments to an atmosphere having a relative humidity of between and until the moisture content of the structures comesto equilibrium and then immersing said structures, while maintaining the same free from tension, into a bath of oil which is substantially inert to said structures, said oil bath having a sufficiently elevated temperature to quickly -volatilize said moisture content of the structures, and maintaining the structures in contact with said bath until after all of the moisture has been volatilized therefrom.

- THEROIjI G. FINZEL.

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