US2338391A - Apparatus for producing preshrune fabrics - Google Patents

Description

C. S. FRANCIS, JR

Jan. 4, 1944.

APPARATUS FOR PRODUCING PRESHRUNK FABRICS Original Filed Dec. 22, 1939 I INVENTOR. Mano/v.9. fkMC/fi, .742

- BY Z Arrzvzzvm Patented J -4, 1944 uuirso STATE Carleton 8. Francis,

algnonby meme" one 31am. Divided The invention relates in general to textiles and, in particular, to an apparatus for stabiliz ing the structure and form of fabrics.

In the conventional method of knitting and weaving fabrics, the yarns are subjected to tension. This is done to secure properoperation of the knitting and weaving machines and to secure uniformity in the finished product. The fifinished state (i. e., in greige goods) are in a condition of stress or stretch, and hence tend to shrink under any circumstances that permit or facilitate movement and contraction .of the fibres.

Fabrics made in such a manner exhibit the tendency to shrink when subjected to wet treatment such as may be encountered in finishing,

or filling direction or both, dependent on the degree of stretch present after finishing. The tendency to shrink will continue until the stretched condition of both the warp and 1111- ing threads has been relieved or until a balanced state of weaving contraction is obtained.

It has been proposed to provide a method of treatmentthat will shrink the fabric in both directions, in a manner analogous to the shrink- I age otherwise occurring in the laundering, washing or other cleaning process. This method is predicated upon the determination that the causes of shrinkage in a fabric subjected to full laundry treatment are mostly mechanical in effeet. The process is, therefore, adapted to me chanically rearrange the fibres and to alter the crimp in the yarns of the'fabric to the same ex tent that these fibres would rearrange themselves and the yarns be criniped if subjected to full laundry washing.

Basically, this process comprises the steps of determining the change in dimension that will take place in the fabricwhen it is subjected to washing, then mechanically shrinking the fabric down to the dimensions so indicated, and f1- nally completing the finishing operation without disturbing these dimensions.

Moreover, prior methods of shrinking fabrics have never been entirely successful when the bres and yarns constituting the fabric in its undergo during wear and laundering frequently s PATENT oi=r1 cs 2,888,301 APPARATUS ron ifr gggmi'i PRESHB Jr.,- Chestnut am, 1a.. a-

ents, to American Vis- Wilmington, DeL, a'eorporaapplication December 22, 1939, Serial No.

and this application 1,180, No. 453,285

'1 Claims- (ci. 20-185) fabric has been composed in whole or in part of artificial fibres, in particular of cut staple rayon.

Amt

Owing to the swelling. and shrinking which artificial filaments undergo on being wetted and dried, fabrics made of such filamentsdo nbt retain the condition produced by the pr operation. However, even with fabrics made of naturabfibres, such as cotton, the prior methods of preshrinking have not given results which were entirely permanent.

Furthermore, the stresses which fabrics unproduce objectionable distortions even though such fabrics have been preshrunk by prior methods. Therefore, it is desirable to provide fabrics which are characterized by having a substantial permanent resistance to distortions of all types in order to preserve a desired structure, form and character in the textile.

On the other hand, it is frequently desired to impart to fabrics a predetermined structure or shape designed to enhance its general utility or to render the textile adapted for some special uses. fabric having a predetermined and definite residual shrinkage so thatthe fabric will maintain its shape and structure during wear and laundering.

Accordingly, it is a general object of the present invention to provide an apparatus for producing a stabilized textile having a predeterterniined structure which is permanent.

It is another object to provide an apparatus for setting and fitting the dimensions of fabrics in a predetermined manner.

Other objects of the invention will'in part be obvious and will in part appear hereinafter.

In the practice of the invention, the permanently preshrunk fabrics are made by mechanically shrinking a fabric containing thermoplastic fibres, fixing the shrunk structure by heating the thermoplastic fibres to render them tacky while the fabric is in its shrunk condition to effeet a substantially permanent adhesion of fibres in the fabric. The present invention provides an apparatus for shrinking a textile web containing thermoplastic fibres comprising, in combination, means for shrinking a fabric, means for applying heat and pressure to said shrunk fabric suf- I For example, it is desirable to provide a s from a mixture of two'types of fibres in accord-- ance with the Process disclosed in the co-pending U. '3. applications Serial No. 157,018, filed August 2, 1937, and Serial No. 201,851, filed April 13, 1938. The shrinkage of the fabric may be partial or complete or to any predetermined amount, and may be effected on woven, knitted, netted or. other fabrics in one or more dimensions. The expression "shrinking" is intended to include all physical or mechanical changes in fibre size, length -and crimp and changes in yarn length, crimp and displacement in. fabrics which produce a decrease in dimension or contraction in the fabric.

The invention accordingly comprises. an apparatus having the elements and the relation of elements one to another all as hereinafter described and the scope of the application of which will be exemplified in the claims.

For a more complete understanding of the nature and objects of the invention, reference should be had to the accompanying drawing in which, x i

Fig. 1 is a 'diagrammatical representation of suitable means for carrying out one embodiment of the process of the invention;

Fig. 2 is a cross-sectional elevation of a fabric before and after shrinkage in the process of the invention; and

Fig. 3 is a cross-section of a fabric after shrinkage in one dimension in accordance with one embodiment of the invention. (1

For the non-adhesive textile fibre there may be used any suitable natural or synthetic fibres of textile-making length of the type thatwill,

not be rendered tacky at the temperatures employed to render the thermoplastic fibres tacky, examples of which are given in my parent co:

pending U. S. application, Serial No. 310,533 filed December 22, 1939.

The potentially adhesive? fibre may comprise A any thermoplastic synthetic resinous-material or thermoplastic non-fibrous cellulosic material capable of being formed into fibres which have an inherent tackiness upon heating to a tempera- .ture below that at which the textile fibres are damaged or'rendered tacky and which are nontacky at room temperature, examples of which are given in my parent application above identified.

The fabrics treated in the apparatus of the invention are preferably fabricated from yarns comprising at least two dissimilar types of fibres at least one of which type is potentially adhesive.

The mixing of the dissimilar fibres may be car-' ried out in a suitable'manner such, for example, as by blending at least two types of fibres before and/or during carding, combining, drafting, but

before completion of the spinning of the fibres into a singles yarn. Thus the two types of fibres maybe mixed and fed together into a carding machine; or slivers'are made from each type independently and the slivers combined by drafting and spinning into'a yarn. Altematively, a yarn containing the potentially adhesive fibre may be twisted or doubled with another yarn of similar type or with av yarn not containing potentially adhesive fibres.

The apparatus is particularly adapted for per.- manently controlling or fixing a shrunk condition in a fabric comprising yarns made from nonadhesive and potentially adhesive fibres mixed together before the completion of, the spinning of the yarn. However, in its broad aspects the apparatus of the invention is applicable for per- 75 manently fixing the structures and form of fabrics after they have been modified by shrinking. It is to be understood that the invention is not limited to any particular means for carrying out 5 the shrinking or the present process. Suitable means for carrying out the shrinking operation involved in the present invention are shown in U. S. Patents Nos. 1,982,320, 1,988,376, 2,021,975, and 2,052,948. By way of illustration, but not by way of limiting the invention, the following methods may be employed for Shrinking fabrics in accordance with the present invention:

A. Stretching a moistened? fabric in one di- 1 mension while permitting or controlling the 'snrinkageinanother dimension. In this embodiment a woven fabric is subjected to moisture and preferably a suitable activating agent and thereafter stretched in. the direction of one of its constituent sets of yarns, either warp or weft, while leaving the other set free from tension or under a. limited tension and drying the fabric while Ii maintaining the tension on the one set of yarns.

The stretching of the one set of yarns causes a contraction and increased crinkle or undulation 3 crinkle or shrunk structure is renderedsubstantially permanent by the adhesion of the fibres in the fabric. This method can be usedfor shrinking knitted fabrics in one dimension.

B. By moistening and stretching the moist fabric in one dimension while permitting or controlling the shrinkage of the fabric in the other dimension whereby the unstretched yarns acquire additional crinkle, drying the-fabric while under tension, again moistening the fabric while free 40 of tension to cause a swelling of the yarns and a consequent shrinkage of the first stretched yarns, and again drying thefabric under pressure,,but free of tension. In this embodiment the potentially adhesive fibres are preferably rendered tacky during or after the final drying step. By

this method a fabric can be permanently shrunk in two dimensions.

C. By moistening a fabric, mechanically compressing the moistened and preferably activated 5o fabric in one dimension whereby the yarns acquire additional'crinkle, maintaining the fabric under pressurev while drying the fabric. The

. activation of the potentially adhesive fibres may take place before, during or after the drying step, and the reactivation of the fabric may take place after the drying by cooling while the fabric is maintained in the pro-shrunk condition. One embodiment of suitable means for carrying out the shrinking in this process is disclosed in U. S. Patent No. 1,861,422.

D. By moistening a fabric while maintaining one yarn system under .tension and permitting or controlling the shrinkage of the other' yarn system, thatis, by permitting the other yarns to crinkle, thereafter mechanically compressing the yarn system previously maintained under tension to shrink that system by increasing the yarn crinkle or undulation. One embodiment of suitable means for carrying out the shrinking in this process is disclosed in U. S. Patent No. 1,861,423.

The activation of the potentially adhesive fibres may be effectedbefore, during or after the drying step and the deactivation of the fabric after the drying of the fabric.

In the mechanicalshrinking treatments lie- 2,888,891 scribed above a chemical swelling agent may be form to effect a substantially permanent adhe sion between the fibres and to set the yarn relationships.

The thermoplastic fibres are rendered tacky by use of hot air, hot water or by contact with hot surfaces, with or without the addition of a solvent or plasticizer, and with or without the use of pressure.

While the fibres are in an adhesive condition, the fabric preferably is subjected to a squeezing or compacting treatment to promote adhesion of the associated fibres at their points of contact as by passing the fabric between pressure rollers. The squeezing may be effected by the means employed for mechanically shrinking fabrics as described hereinafter.

Deactivation may be accomplished by heating to a higher temperature, as in the case of a heatconvertible resin fibre, or by cooling, as in the case of a thermoplastic resin or cellulose derivative fibre.

A 'plasticizer advantageously may be applied to the thermoplastic fibres and/or to the fabric before the activation of the'flbres as described in parent co-pending application Serial No. 310,533, filed December 22, 1939.

The activation of the thermoplastic fibres takes place preferably before the shrinking operation occurs and the fabrics are subjected to the shrinking operations while the thermoplastic fibres are in an activated condition. The deactivation of the adhesive or adhesive fibres takes place while the fabric is maintained in the shrunk condition. If the fabric is to be shrunk give a product having increased tensile strength and lower stretch and shrinkage. If the activation'is such as to form an adhesive, the adhesive will cause the other fibres to be permanently adhered and the shrunk structure permanently set.

While a knitted fabric as, or course, only one yarn system, it may be shrunk in a manner similar to a woven fabric by one or more of the methods Just described which.- are appropriate therefor and the present invention is intended to vinclude fixing the shrunk? structure of both woven and knitted fabrics.

Referring to the Figure 1, a'dry fabric l containing thermoplastic fibres is passed between the pressure rolls 2 and subjected to tension between the rolls 2 and the calender 3 to cause a weaving contraction to take place' in the direction of the filling. While the fabric is held to a desired width by means of a suitable tenter frame F, there is applied to it moisture and a plasticizer by means of sprays l and 4'. The

plasticizer is any suitable substance which is miscible with the thermoplastic fibres and capable of reducing the temperature at which-such fibres become tacky upon-heating. The fabric containing moisture and plasticizer is now in two dimensions, the deactivation of the adhesive or of the adhesive fibres preferably takes place after the completion of both shrinking operations while the fabric is in a relaxed state or under controlled tension. The shrunk structure should not be placed under distorting tensions during the deactivation treatment. For instance, if the deactivation is to take place by heating or cooling, the fabric may be passed over a heated or cooled drum in the manner just described or over a series of rollers which are heated or cooled by known means.

The properties of the finished product depend upon various factors, such as the nature and proportion of thermoplastic fibres; the extent of the activation thereof; and the tacky condition of the fibres during squeezing or pressing and the nature of the deactivation and the extent of shrinking. The extent of activation may be varied considerably, depending upon the relative proportions of the types of fibres, the properties of the thermoplastic fibres, and the effect desired in the product. The thermoplastic fibres may be rendered superficially adhesive; or rendered plastic and tacky without losing their fibrous form; or made to lose their fibrous structure and form an adhesive. The tacky-thermoplastic fibres will cohere to each other and adhere to the other fibres to fix the position thereof to blanket passing about the roll 1.

passed over the calender 3 which is heated to a temperature sufficient to render the thermoplastic fibres tacky. While the fibres are in a plastic and tacky condition the fabric is shrunk by passing it between the applicator roll I and the heated ironer 8 which is curved to conform to the arcuate surface of the applicator roll I and fed between an endless blanket 5 moving in surface contact with a heated rotating drum- 6. Between the calender 3 and the ironer 8 the fabric may again be moistened as with steam to keep the yarns pliable if necessary. Shrinking in a warpwise direction is effected as'the fabric passes over the curved surface of,the In passing between the blanket 5 and heated drum 6, the fabric is subjected to heat and pressure whereby the resin fibres are maintained tacky and the weaving contraction temporarily set.

As the fabric l emerges from the blanket 5 and.

the drum 6, at the point P, it is cooled by traverse through the air around rolls l0 and H or preferably through the cooling chamber it through which cold air is passed. The cooling of the fabric renders the thermoplastic material non-tacky, thus creating a strong and substantially permanent adhesion between the fibres in the fabric and permanently setting the weaving contraction. Additional pressure may be obtained on the blanket 5 by use of one or more pressure rolls such as roll 9.

While the plasticizer may be allowed to remain in the fabric if it is of a non-volatile type, it is desirable inmost cases to remove the plasticizer thereby elevating the temperature at which the resin can again be rendered tacky. For this purpose the fabric is passed from the roll ii through a solvent it of the plasticizer contained in vessel 13. From the solvent E2, the fabric i may be passed to a heated dryer (not shown) of conventional type for the purpose of evaporating the residual solvent. It is desirable in most activated adhesive fibres causesthe component fibres of the yarn to adhere to each. other. This adherence of the fibres renders permanent the crinkle imparted to the yarn by the shrinking operation and anchors the yarns to each other in their new relationship. The shrunk condition thus rendered permanent by thedeactivation need not be the ultimate weaving contraction produced by repeated launderings, but may be a shrunk condition intermediate between that of the untreated fabric andthat of the ultimate shrinkage after laundering. This effect is not obtainable by the use of the shrinking operation alone, but only by the use of the combination of the shrinking with the setting operation of the present invention.

Accordingly, the present invention provides, inter alia, apparatus such that a fabric may be shrunk toa predetermined but not necessarily the ultimate shrunk condition, and such shrunk condition rendered permanent so that the fabric neither shrinks nor expands to any substantial zextent upon laundering, dry cleaning or wearing. Thus, thepresent invention provides an apparatus for setting and fixing the dimensions of fabrics in a predetermined manner and for establishing a predetermined and residual shrinkage in textiles arid these results may be obtained in fabrics made from artificial filaments, in particular, cut staple rayon, as well as in fabrics made from natural fibres;

The effect of the combined shrinking and setting operations of the present invention may be illustrated by reference to Figs. 2 and 3 of the drawing. The untreated fabric may berepresented by the upper view of Fig. 2 in which the warp yarns l5 and the weft yarns l6 show only a slight undulation and the yarns are relatively distant from one another, giving the fabric a loose, porous appearance. When the fabric is shrunk in one dimension only, for example, by stretching the warp yarns of a pm-moistened fabric, while permittingvor controlling the width- .wise contraction, there is produced a product as "shown in Fig. 3, in which the warp yarns I5 liesubstantially in the same plane, while the weft yarns are given an increased crinkle and a decreased over-all length. If the fabric shown in Fig. 3 be subjected to warpwise shrinkage as by mechanically compressing the warp yarns longitudinally by any suitable method, the warp yarns are given an increased crinkle, thus bringing the weft yarns closer to each other. As a result of the longitudinal contraction in the warp and weftyams, the final product will have the structure illustrated in the lower view of Fig. 2 in which both series of yarns have a substantial crinkle and the yarns lie relatively close together in contrast to the untreated fabric.

Since certain changes in the apparatus and in carrying out the above process, and certain modiflcations in the article which embody the invention of this and the parent application may be made without-departing from its scope, it is were \ intended that all matter contained in the above j'de'scription or shown in the acoompanylngdrawing' shall be interpreted as illustrative and not into. limiting sense. g

This application is a division of my co-pend ing U. S. application, Serial No. 310,533 filed De 'cember 22, 1989, now U. 8. Patent No. 2,3193%. .No claim is made to the process ofshrinking and stabilizing fabrics or'the articles so produced in this application since that subject matter is claimed in said co-pending application.

' Having described my invention, what I claim as new and desire to secure by Letters Patent is:

I 1. Apparatus for shrinking a textile web containing thermoplastic fibres comprising, in combination, means for advancing a textile web in a warpwise directiommeans for applying a swelling'agent to said web, means for stretching said web warpwise sufiicient to increase the crinkle in the weft yarns, means for heating said web sufficient to render said thermoplastic fibres tacky, means for shrinking said web warpwise by applying compression parallel to the surface of the web, and means for applying pressure to the compressed web.

2. Apparatus for shrinking a textile web containing thermoplastic fibrescomprising, in combination, a pair of pressure rollers, a heated calender, means to subject a web passing between said pressure rollers and said calender to longitudinal tension, means to hold said web to the fabric to heat and pressure,-and means to cool definite widthameans to apply a liquid to said web while held by said last means, means to mechanically shrink the web after passage over said calender, means to subject the said shrunk v said shrunk fabric.

3. Apparatus for shrinking a textile web containing thermoplastic fibres comprising, in combination, a pair of pressure rollers, a heated-cal ender'adapted with said pressure rollers to subject a web passing between said pressure rollers and said calender to longitudinal tension, means between said pressure rollers'and said calender to hold said web to the definite width, means to apply a liquid to said web while held by said last means, means to mechanically shrink the web after passage over said calender, and means to subject the fabric while it is in a shrunk condition to heat and pressure.

4. Apparatus for shrinking a textile web containing thermoplastic fibres, comprising, in combination, means for advancing a textile web in a warpwise direction, means for stretching said web warpwise sumoient to increase the crinkle in the weft yarns, means for shrinking the web warpwise by applying compression parallel to the surface of the, web, and means for heating the web sufficiently to render said thermoplastic fibres tacky, and means, in addition to saidwarpwise shrinking means; to subject the fabric to pressure after said warpwise shrinking and while said fibres are in a tacky condition to cause the tacky material to bind fibres in said product.

5. In an apparatus for shrinking a textile web containing thermoplastic fibres, the combination of, means for shrinking -a fabric weftwise' said warpwise shrinking and while said thermo-. plastic fibres are tacky to cause the tacky material'to bind fibres in said product.

6. In an apparatus for shrinking a textile web containing thermoplastic fibres, the combination of, means for shrinking ajabric weftwise and warpwise, means for app y heat to S fabric prior to warpwise shrinking suificient to render the thermoplastic fibres tacky, means, in addition to said warpwise shrinking means, for applying pressure to said fabric after said warpwise shrinking and while said thermoplastic fibres are tacky to cause the tacky material .to bind fibres in said product, and means for cooling said web to render the thermoplastic material nontacky.

7. In an apparatus for shrinking a textile web containing thermoplastic fibres, the combination of, means for moistening a fabric, means for shrinking a fabric weftwise and warpwise, means for applying heat to said fabric prior to said warpwise shrinking sufiicient to render the thermoplastic fibres tacky, and means, in addition to said warpwise shrinking means, for applying pressure to said fabric after said warpwise shrinking and while said thermoplastic fibres are tacky to cause the tacky material to bind fibres in said product.

CARLETON S. FRANCIS, J a.

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