US2020304A - Textile materials - Google Patents

Description

Patented Nov. 12, 1935 UNITED STATES PATENT OFFICE TEXTILE MATERIALS ware No Drawing. Application May 11, 1932, Serial No. 610,703. In Great Britain May 15, 1931 14 Claims.

appear and the fabrics so obtained have long been highly prized on account of their great beauty and pleasing handle. The production of crepe fabrics by utilizing highly twisted yarns consisting of or containing filaments of artificial silk has however been accompanied by considerable difiiculties, more particularly in the case of utilizing highly twisted yarns made of filaments of cellulose acetate.

We have now found that in the production of the highly twisted crepe threads improved re-,

sults may be obtained by treating thethreads with solutions, preferably aqueous, of certain organic or inorganic acids or salts thereof, prior to the application of at least part of the high degree of twist. Treatment with the solutions of acidsor salts in the foregoing manner is particularly beneficial in the case of crepe threads consisting of or containing filaments of cellulose acetate or other cellulose esters or ethers, and is preferably applied to the yarns afterv the application of a part of the requisite twist.

' A wide variety of acids or salts thereof may be utilized in accordance with the invention. It has been found however that the nature of the acid radicle may have a considerable influence on the results obtained. Very favourable is the effect of the ferrocyanide, thiosulphate, ferricyanide, citrate, lactate, tartrate, dihydroxy tartrate, sulphate, oxalate and phosphate radicles. These radicles it may be noted are high in the Hofmeister series of radicles arranged in the order in which they are effective in causing precipitation or coagulation of colloidal solutions. Other acid radicles which may advantageously be employed are those of diand polybasic acids generally and in particular those of organic dior polybasic acids or hydroxy mono-, di-, or polycarboxylic acids, as further examples of which may be mentioned those of mucic and saccharic acids. The nature of the cation in the compounds applied to the threads appears to be of less moment, though most satisfactory results are generally obtained when the cation is hydrogen,

or an alkali metal, e. g. lithium, sodium or potassium. As examples of specific salts which may be applied to the threads mention may be made of potash alum, sodium thiosulphate, sodium citrate, sodium tartrate and Rochelle salt.

The proportion and concentration of the solution of the acid or salt applied may vary Within Wide limits, for example citric acid may be applied in the proportion of lper cent or more of the weight of the threads in the form of aqueous solutions of 10, 20 or 30 per cent concentration or even of concentrations up to that of saturated solutions.

As indicated above the acid or salt thereof is preferably applied to the yarns after application of a portion of the requisite high degree of twist. Thus, for example, yarn of low twist may be twisted to 15-30 turns per inch, the acid or salt thereof applied and the yarn thereafter twisted to the high degree necessary in the final threads, for example 45-70 turns per inch. In particular, very good results may be obtained in the case of yarn of about 100 denier and containing about 26 filaments by first twisting up to about 25 turns per inch, then applying the solution of the acid or salt and thereafter twisting up to 50-60 turns per inch or more.

The proportion of twist inserted in the yarn before the application of the solutions of the acids or salts may vary within wide limits. Thus, for instance, where the total twist is to be 65 turns per inch, the.yarn may first be twisted to turns per inch, then treated with the acid or salt solution, and thereupon an additional 55 turns per inch applied to give the necessary total twist. Again, if desired 40 turns per inch may first be applied and 25 turns per inch following the treatment.

-The twist may if desired be applied in three or more equal or unequal stages, the acid or salt treatment being applied between any or all of the stages.

In practice, it has been found advantageous to apply in the first place a degree of twist of the order of that necessary to cause a close packing of the filaments of the yarn and then to apply the acid or salt treatment and thereafter to impart the degree of twist necessary to give rise to crepe effects of the desired character. Particularly useful results are obtained, with yarn of about 100 denier containing 26 filaments, by twisting to at least to turns per inch for example 20 to 30 turns per inch e. g. to 25 turns per inch, treating with the solution, and thereafter twisting to 60 to 70 turns per'inch. It will be appreciated that the exact degree of twist necessary to give the desired close packing of the filaments is dependent in any particular case on the total denier of the yarn and the number of the filaments of which it is composed. Thus for yarns of a given total denier the twist required to effect close packing is greater the smaller the number of filaments. Again, for yarns containing a given number of filaments the first stage twist necessary to cause close packing varies inversely as the diameter of the filaments or the square root of the filament denier. In general for yarns of between 70 and 170 denier and containing from to 70 filaments the degree of twist necessary to give close packing of the filaments is between about 10 and turns per inch.

It is not however essential to apply, before the acidor salt treatment, sufficient twist to cause close packing of the filaments as very satisfactory results may be secured if the initial twist is somewhat lower. The crepe effects obtained appear to be largely dependent upon the degree of twist imparted after the acid or salt treatment and to be independent of the twist inserted prior to the treatment providing that the latter is not excessively low as compared with that required to effect close packing of the filaments.

It appears possible that the treatment of the partially twisted yarns with the acid or salt solution results in the production of a yarn of more or less firm character in which the filaments are bedded firmly together, and that this yarn, in which the filaments may be described as set, when further twisted, twists substantially as a whole and tends to assume a spiral form.

The twisting of the yarns may be effected in any convenient manner. It has been found advantageous however, particularly when inmrting twist after the acid or salt treatment, to utilize twisting devices of the type in which the yarn is twisted as it is drawn off from a rotating package and to prevent the applied twist running back to the bobbin. This result may very conveniently be attained by means of the device described in U. S. Patent No. 1,784,581.

The application of the acid 'or salt solutions to the yarns may be effected in any convenient manner. Thus, the yarn wound on to bobbins or the like may be immersed in the solutions, excess liquid being if desired subsequently removed by centrifuging or the like. One method which enables the yarn to be quickly and thoroughly impregnated with the solution consists in winding the yarn on to a perforated or porous tube or bobbin (which may serve as the take-up device employed in twisting the yarn or may be wound with twisted yarn in a back-winding operation) and placing the package on a perforated tubular support which is supplied with the solution under pressure. The solution is thus forced outwardly through the yarn on the package and rapidly and completely wets out the yarn. The solution may however be sucked through the package, or suction and pressure may be applied alternately to ensure complete impregnation of the package. In order to simplify the treatment, several packages of yarn may be placed on to a single perforated tube, or a plurality of perforated tubes, each supporting one or more packages, may be connected to a common pressure or suction supply, e. g. by mounting the tubes radially about a central pipe which is in connection with the source of pressure or suction. The solutions may be applied to the yarns at ordinary tempera tunes or at higher temperatures, for example at 30 to 80 C.

Again the solution may be applied to the travelling yarn, for example by spraying or by passing the yarn through baths of the solution or over wicks, rollers or other devices adapted to feed the solution on to the yarn. The solution may also be applied simultaneously with a twisting operation. For example the initial twist may be applied on a machine of the type in which twist is applied as the yarn is drawn from its package, the drawn off and twisted yarn being passed through a body or spray of the desired solution on its way to the re-winding device.

The yarn may be allowed to stand for a time after the application of the solution in order that it may be thoroughly wetted thereby. Further twist may be applied directly to the yarn in the wetted state or after subjecting the yarn to a drying operation in order to remove a part or the whole of its moisture content. The proportion of moisture remaining prior to the further twisting operations may be adjusted to that most favourable to the production of the yarn capable of giving good crepe fabrics. The aforementioned drying of the yarn, where desired or requisite, may be effected in any convenient manner. For example, the yarn may be passed over heated drums or through another suitable drying device after wetting but prior to re-winding.

Again, where the yarns are wound on perforated or porous tubes or bobbins, drying, complete or partial as desired, may be effected by blowing or sucking air or other gas, which may be heated, through the package. may be readily carried out on packages which have been treated with the solution with the aid of pressure and/or suction as described above, by blowing or sucking air or other gas through the packages while they still remain on the perforated tubes on which they were mounted for the liquid treatment.

If desired the solution may contain agents facilitating the wetting of solids by liquids, which agents should preferably be stable to the acids or salts employed. Again wetting agents or indeed hygroscopic or deliquescent substances generally may be incorporated in the yarns or filaments thereof prior to twisting. For example cellulose acetate solutions containing hygroscopic substances, for instance magnesium chloride, potassium acetate or calcium chloride or nitrate, may be spun into filaments and the latter formed into yarns and treated in accordance with the invention.

Cellulose acetate yarns to which a high degree of twist has been applied in the manner described, may be incorporated into fabrics and the latter subjected to a scouring operation or like aqueous treatment, whereby the crepe effects may be enhanced. Such treatment may comprise for instance a treatment in water alone, for example at ordinary or slightly raised temperature followed by scouring in a hot aqueous soap solution.

The crepe threads produced and employed in accordance with the present invention may if desired be sized at any suitable stage of their manufacture. In this connection particular mention may be made of sizing materials which may be caused to swell without becoming soft or yielding by suitable treatment, particularly by a subsequent scouring treatment where such is employed. The sizing materials may be selected with advantage according to the principles laid down in British Patent No. 348,589. Again the crepe threads or the filaments contained therein Such drying I may be sized with or provided with a coating of a cellulose or a cellulose derivative as described in British Patent No. 357,169, or with a coating of a polymerized vinyl compound or other polymerized or condensed organic compound as described in British Patent No. 352,451. Any sizes or coatings may be applied intermittently to the threads as described in U. S. Patent No. 1,966,440 and British Patent No. 365,041.

Sizing materials where employed are preferably applied to or formed on the crepe threads prior to the application of a substantial degree of twist, and conveniently may beapplied simultaneously with the solution of an acid or salt thereof. A casein size saturated with citric acid or other suitable organic acid may for example be employed.

As stated previously the invention is of particular value in connection with the production of crepe fabrics with the aid of highly twisted yarns consisting of cellulose acetate filaments. Such filaments may be of any desired character and produced by any desired process. Thus filaments of bulbous or rounded section or of fiattened section may be used. Further the filaments may be of substantially uniform section or may vary in section from point to point along their length. Crepe threads comprising filaments of other organic derivatives of cellulose may be employed in an analogous manner. As examples of such cellulose derivatives may be mentioned cellulose formate, propionateor butyrate or other cellulose esters of organic acids, or methyl, ethyl or benzyl cellulose or other cellulose ethers. If desired crepe threads consisting of or comprising filaments of other materials may be employed, for example filaments of silk, cotton, or of artificial silk of the regenerated cellulose type. The crepe threads may also be composed of filaments of two or more different kinds whether in respect of material or denier or both. Thus there may be used threads containing both filaments of cellulose esters or ethers and filaments of natural silk or regenerated cellulose artificial silk, or threads containing filaments of esters of difierent acid value, or threads containing cellulose ester or ether filaments of two or more different deniers or cross sections. Further, the crepe yarns may consist, wholly or in part, of staple fibre i. e. relatively short lengths of filament.

The degree of twist imparted to the crepe threads made or used according to the present invention, may be similar 'to that commonly employed in the case of crepe threads of natural silk in the gum. For example, as previously indicated, a twist of from 45-70 turns per inch may be employed. In'general a twist of about 60-65 turns per inch has been found to give highly satisfactory results, but higher twists. for example 75-85 or more turns per inchymay be employed with advantage in some cases, particularly when the filaments are of very low denier (see British Patent No. 357,577). Any other suitable degree of twist may however be employed according to the nature and denier of the filaments constituting the crepe threads and according to the effects it is desired to produce. Moreover the twist may be irregular in character, varying from point to point along the crepe thread, as described in British Patent No. 358,585. Further, the requisite high degree of twist may be applied in two or more stages with or without intermediate sizing, 'in the manner described in British Patent No. 357,576.

The highly twisted crepe threads may be incorporated in the fabrics in any suitable manner, for example the weft alone may be wholly or partially composed of such threads or the warp may also contain them. In the former case the finished fabrics exhibit chiefly shrinkage in the direction of the weft. It is found particularly convenient however, in general, to employ threads of relatively low twist in the warp and to employ in the weft both crepe threads having a lefthand twist and crepe threads having a righthand twist. Such threads may be disposed in the fabrics in any convenient manner, for example pairs of threads of left-hand twist may alternate with pairs of threads of right-hand twist. A further method of constructing the fabrics is to weave composite crepe threads consisting of a yarn of high twist doubled with a yarn of low twist, or consisting of two yarns of high but opposite direction of twist, the yarns being prepared in accordance with the processes of the invention. In this manner crepe fabrics may be readily produced without the necessity for the employment of a loom capable of weaving two different types of yarn such as is necessary whenalternate picks of yarn of left-handed twist and yarn of right-handed twist are to be woven. In this connection reference is made to British Patents Nos. 332,903 and 375,355.

Where the fabrics comprise yarns of low twist, the latter may be either of the same material. or of a different material from that of the highly twisted crepe threads. For example, where the crepe threads are composed of cellulose acetate filaments, the sa d yarns of low twist may be composed of cotton or of a regenerated cellulose type of artificial silk.

In the case of fabrics containing low twist yarns as well as the highly twisted crepe threads, such yarns, particularly when forming the warp of the material, will usually be sized. In this event it has been found beneficial to employ sizes which are easily removed or at least easily soft ened by aqueous treatments subsequently applied to the fabrics. Indeed, if desired the said treatments may be modified, for example in respect of temperature or other condition, or a special treat ment may be applied, for the purpose o f softening or removing the size on the yarn of low twist. Preferably the size on the said low twist yarns should be more easily softened or removed than any size which may have been applied to the highly twisted crepe threads in the fabrics. Again, when utilizing yarns of low twist in conjunction with the crepe threads of high twist, the said low twist yarns may be of such character or be so treated as to be less readily wetted than the crepe threads. For instance they may be oiled with an animal, vegetable, or mineral oil prior to incorporation into the fabrics.

The invention is illustrated but not limited by the following example:-

Example Cellulose acetate yarn of 100' denier and containing 26 filaments is twisted to 20-26 turns per inch and wound onto bobbins, the yarn being passed on its way to the bobbins, through a 10% citric acid solution, or a 30% solution of sodium citrate, or a saturated solution of sodium thiosulphate, or a. 5% solution of dihydroxy tartaric acid. The twisted and impregnated yarn is then, while still damp, twisted up to turns per inch on a twisting machine of the kind described in U. S. Patent No. 1,784,581. Yarn of right-hand as well as yarn of left-hand twist is prepared in this manner. The treated and twisted yarns are then woven into a cellulose acetate warp oi yarns of low twist, two picks of right-hand twist alternating with two picks of left-hand twist, the resulting fabric being then treated first in water at 30 C. for 15 to 30 minutes and thereafter in a three grams per litre soap solution for l-l hours, the temperature being raised from 30 to 80 C. during this period. The fabric is finally washed off, hydroextracted and dried without tension.

Fabrics may similarly be produced from cellulose acetate yarns of other deniers and containing diiferent numbers of filaments, the degree of twist applied in the two stages being adjusted according to the particular yarn.

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

1. In the production of highly twisted crepe threads from yarns consisting of or containing cellulose ester or ether filaments, treating the yarn with a solution containing an acid radicle having a high coagulating or precipitating action on gels of the materials of the crepe threads after the application of a part only of the high twist.

2. Process for the production of highly twisted crepe threads from yarns consisting of or containing cellulose ester or ether filaments, which comprises applying a part of the high degree of twist, treating the yarns with aqueous solutions containing acid radicles having a high coagulating action on gels of the material of the crepe the requisite twist in a single stage.

3. In the production of highly twisted crepe threads, the step of treating the yarn with a solution containing an acid radicle having a high coagulating action on gels of the material of the crepe threads after the application of a part only of the high twist.

4. Process for the production of highly twisted crepe threads from yarns containing filaments of organic derivatives of cellulose which comprises twisting the yarns to such a degree as to effect a close packing of the filaments, treating the yarns with aqueous solutions containing acid radicles having a high coagulating action on gels of the cellulose derivatives and thereafter applying the remainder of the requisite high twist in a single St e.

5. Process for the production of highly twisted crepe threads from yarns containing filaments of cellulose acetate which comprises twisting the yarns to such a degree as to effect a close packing of the filaments, treating the yarns with aqueous solutions containing acid radicleshaving a high coagulating action on gels of the cellulose acetate and thereafter applying the remainder of the requisite high twist in a single stage.

6. Process for the production of highly twisted crepe threads from yarns containing filaments of cellulose acetate which comprises applying a part of the high degree of twist, treating the yarns with aqueous I solutions containing acid radicles having a high coagulating action on gels of cellulose acetate and thereafter applying the remainder of the requisite high twist in a single stage.

7. Process for the production of highly twisted crepe threads from yarns containing filaments of cellulose acetate which comprises applying a part 5 of the high degree of twist, treating the yams with aqueous solutions containing radicles oi. acids which are at least dibasic and thereafter applying the remainder of the requisite high twist in a single stage. 10

1 8. Process for the production of highly twisted crepe threads from yarns containing filaments oi cellulose acetate which comprises applying a part of the high degree of twist, treating the yarns with aqueous solutions containing radicles of orii ganic acids having at least two carboxyl groups and thereafter applying the remainder of the requisite high twist in a single stage.

9. Process for the production of highly twisted crepe threads from yarns containing filaments of S0 cellulose acetate which comprises applying a part of the high degree of twist, treating the yarns with aqueous solutions containing the thiosulphate radicle and thereafter applying the remainder of the requisite high twist in a single 88 stage.

10. Process for the production of highly twisted crepe threads from yarns containing filaments of cellulose acetate which comprises applying a part of the high degree of twist, treating the yams 80 with aqueous solutions containing the citrate radicle and thereafter applying the remainder of the requisite high twist in a single stage.

11. Process for the production of highly twisted crepe threads from yarns containing filaments 85 of cellulose acetate which comprises applying a part of the high degree of twist, treating the yarns with aqueous solutions containing an alkali metal citrate and thereafter applying the remainder of the requisite high twist in a single 40 stage. a

- 12. Process for the production of highly twisted crepe threads which comprises twisting cellulose acetate yarns of from 70-170 denier and contain-. ing 25-70 filaments to between 10 and 30 turns per inch, treating the yarns with aqueous solutions containing acid radicles having a high coagulating action on cellulose acetate gels and thereafter twisting the yarns to a high degree.

13. Process according to claim 12, wherein the threads are finally twisted to 60-70 turns per inch.

14; Prpcess for the production of highly twisted crepe threads froin yarns containing filaments of cellulose acetate which comprises applying a part of the high twist and simultaneously treating the yarns. with aqueous solutions containing acid radicles having a high coagulating action on cellulose acetate gels and thereafter applying the remainder of the requisite high twist by forming the yarn into a package, rotating said package 00 and drawing the yarn of! over the end of the rotating package while preventing twist from running back to the package.

HENRY DREYFUS. 5 WILLIAM ALEXANDER DICKIE. ROBERT WIGHTON MONCRIEFF.