US2353525A - Elastic fabric - Google Patents

Description

M. c. TEAGUE July 11, 1944.

' ELASTIC FABRIC Original Filed July 28, 1938 ATTORNEY:

Patented July 11, 1944 UNlTED STATES PATENT OFFICE ELASTIC FABRIC Merwyn C. Teague, Ridgewood, N. J., assignor to United States Rubber Company, New York, N. Y., a corporation of New Jersey 7 Original application July 28, 1938, Serial No.

221,811. Divided and this 21, 1941, Serial No. 379,986

3 Claims.

Elastic fabrics have previously been made by incorporating in the fabric during the weaving or knitting or other manufacturing operation rubber threads which may be bare or covered with textile yarns. Other types of elastic fabrics have been produced from stretchable textile fabrics by calendaring sheet rubber onto 'a surface of the fabric, or by sandwiching sheet rubber between plies of the fabric, or by treating the fabrican elastic fabric, butwith no greater and generally not as great, ultimate elongation in any direction than was originally present in the textile fabric before treatment.

By the present invention, an elastic fabric may be produced having increased capacity to stretch in one or more directions without diminishing the capacity of the fabric to stretch inany other direction. Textile fabrics may be made elastic and have imparted thereto a capacity or an increased capacity to stretch crosswise or lengthwise or in' both directions without lessening the capacityto stretch in any other direction. Knitted fabrics having a crosswise or widthwise stretch may be made into-elastic fabrics having an increased crosswise stretch without diminishing the amount of stretch. if any, in a lengthwise application February .showing the fibers ina separated condition.

The fabric embodying the present invention is made by depositing rubber from a rubber-containing fluid such as a solvent rubber cement or an aqueous-dispersion of rubber, such as latex, on to a fabric which is condensed in at least one direction. The rubber thus deposited sets the fabric and maintains it normally in the condensed direction, or may be-made into elastic fabrics having a lengthwise stretch or an increased lengthwise stretch without. diminishing the amount of stretch or ultimate elongation crosswise of the fabric. Knitted-and loosely woven fabrics and net, materials composed entirely of textile threads or yarns and which may contain bare or covered rubber threads, may be. trea according to the present invention. Such fabrics are hereinafter referred to as textile fabrics.

In the drawing; fi

Fig. 1 illustrates more or less, diagrammatically a proces by which the elasticj fabric embodying the present invention may be made;

Fi 2'illustrates a knitted textile fabric to be treated according to the method'described herein:

condition. The textile fabric when condensed ha had imparted to it a capacity to stretchin the direction of the condensation of the fabric and to an amount substantially equal to the condensation, and in addition retains all the capac- Y 'ity' for stretching it had before the treatment. The rubber imparts to the fabric as a whole the capacity of speedy retraction from stretched condition, thereby making it what is commonly. termed an elastic fabric.

tion of itswidth orlength, and the fabric is condensed widthwise, or lengthwise, or both, and

then treated with a rubber-containing fluid so as to deposit-'therubber on to the fabric and set the. condensed condition, the woven fabric will have imparted to it a capacity to v the same stretch and to speedily retract from a stretched condition in the direction or directions and to the extent of the condensation of the fabric. In fabrics having a capacity .to stretch before treatment, as is generally the case with knitted fabrics, whatever capacity to stretch in one or more directions that is imparted to the fabric by the condensation process isin addition to whatever capacity to stretch the fabric might already have.

The rubber deposit niay be very light, as produced with a spray, and in such case the porosity of the fabric need be scarcely diminished by virtue of the rubber deposit. If desired, however, heavier films of rubber may be deposited on the fabric, to produce a continuous deposit and which may in addition to maliing the fabric elastic and 1m parting a capacity to stretch in one or more directions produce desired water-proofing qualities. The rubber 'may be used with the deposit on one I surface as in the manufacture of rubberizedfab- Figs. 3 and 4 illustrate the same fabric after rice for shoe manufacture or 'for the manufacture If the initial material to be treated is a woven fabric substantially without a capacity to stretch either in thedirecply roll I8 and -hesion of the fabric l1 contraction of the belt between the rolls as froma spray device 26 of rubber lined clothing and the like, or the fabrics may be plied up with the surfaces on which the rubber has been deposited in contact with soch other in order to produce laminated fabrics, both the surfaces of which are of textile material,

and which may simulate an inelastic material and yet be an elastic fabric with the desired capacity to stretch in one or more directions.

Fig. 1 of the drawing illustrates diagrammati cally, one method of carrying out the invention by condensing the fabric in a lengthwise direction but as will be described later, other methods of condensing fabric in a lengthwise direction, or methods of condensing the fabric in a widthwise direction, or in both directions, are readily. accomplished. Referring more particularly to Fig. 1 of the drawing, an elastic belt Ill, preferably made of rubber, is passed through a pair of pinch rolls H, under a container I2 from which a supply of an adhesive material l3, such as glue, israpplied to the belt and evenly spread thereon by a spreading knife 14. The adhesive may be sprayed on the belt, if desired. The belt passes over a heater or cooler plate l5 to increase the viscosity or tackiness of the adhesive on the surface of the belt and make it sufficiently tacky to adhere a fabric material thereto. The belt travels through a pair of pinch rolls I6 operating at greater surface speed than the pinch rolls H and the rubber belt is thus stretched between the pinch rolls II and IB. As the belt in its stretched condition goes between the pinch rolls I6, or slightly in advance ofthe pinch rolls l6 if desired, the textile fabric H which is to be treated is unrolled from supis' made to adhere to the glue or other adhesive l3 on the surface of the belt, as by the pressure of the pinch rolls l6. Further increasing of' the viscosity 'of the adhesive l3 may take place after passage through the pinch rolls" I6 by means of the heater or cooler l9 situated on the egress side of the pinch rolls. The belt ill after passage through the pinch rolls I6 is allowed to relax, preferably'in stages as by travel through pinch rolls 20, 2| and 22 rotating at diminishing surfacespeeds from that of the rolls IS, the surface speed of the last pair of rolls 22 being preferably approximately equal to the surface speed of the rolls ll. Between the pinch rolls 20, 2| and 22 may be positioned additional heaters or coolers 23 and to further dry or increase the viscosity of the adhesive l3 on. the belt as the belt relaxes to insure adto-the belt during the IS and 22'. When the belt leaves the pinch rolls 22, the fabric II which is adhered to the belt while the belt was in a stretched condition will have been condensed in alengthwise direction and in an amount approximately equal to the amoun of contraction of the belt between the pinch rolls {l6 and 22. To the condensed fabric secured by the adhesive 13 to the belt surfaceis appllied'a rubber-containing fluid, for example latex 25, or if desired from a other device. The

conventional spreading or the fluid 'on to the rubber. is deposited from fabric'by a chemical drying step as in passage through the drier 21.

The rubber thus deposited on the fabric sets the i fabric and is'capableof maintaining the fabricnormallyinthe condensed condition. In ordinary practice where a vulcanizable latex composition is. used, completely cure this drying may partially or the rubber deposit. In order coagulating .and/ or by l a 1 containing fluid takes belt to beeasily separated by means of pull rolls 30. In some cases the heat of the drier 2'l sufficiently softens the adhesive while drying the rubber deposit to eliminate the necessity for further softening of the adhesive as by the steam chest 29. The fabric as it is separated from the belt I0 is drawn by the pull-rolls 30 through a washer 3| to wash off the adhesive remaining on the fabric surface and is then passed through a drier 32 which if desired may vulcanize to any degree or complete the vulcanization of the rubber deposit. The rubber coated fabric may be doubled or plied before or after rolling up as at 33. The belt after separation of the fabric from the surface of the same passes through a washer 34 to remove excess adhesive from the surface and then passes between drying plates 35 and back to the pinch rolls I l.

The rubber belt may be contracted from its stretched condition at the pinch rolls 16 in one step rather than in a series of steps as by the series of pinch rolls of gradually diminished surface speeds, if desired; The adhesive may be a water-soluble material such as the glue described above or in case it is desirable to elimihate all water-soluble substances from the elastic fabric, shellac or copal or cellulose compounds or other gums or resins which are soluble in rubber non-solvents instead of a watersoluble adhesive may be' used, whereupon the belt, after deposition of the rubber on the fabric, may be passed through such a rubber non-solvent to remove the adhesive. The rubbermay be deposited from the rubber-containing fluid, if a latex composition, by a chemical coagulation of the rubber particles as by treatment with a latex coagulant, which may be admixed with the adhesive. to at least aid in setting the fabric in the condensed condition. The rubber-containing fluid may contain the rubber in vulcanized condition in which case no further vulcanizat on is necessary. Preferably, the rubberthe form of a vulcanizable latex composition, and where the fabric is to be utilized without doubling or plying, substantially complete vulcanization is made to take place by the time the elastic fabric leaves the drier 32. Where two fabrics treated according to the invention are doubled or plied-with their rubber sides in contact or an untreated fabric is so doubled or plied to the rubber side of a treated fabric to form a laminated fabric, at least complete vulcanization of the deposit is preferably prevented until after the plying operation. The rubber-containing fluid may be so modified as to adjust the feel, modulus of stretch and other properties of the finished condensed fabric as described. Instead of single or plied fabrics, as

above described. therubber side of a single tex- I tightly between two stretched belts, the tensions it is also contemplated that the rubber-containcut lengths placed cross-wise on the belt before the pinch rolls l0.

If it is desired to impart a stretch or to add additional' stretch to continuous lengths of a fabric in a cross-wise direction, then a rubber belt similar to the rubber belt I may be used as in the apparatus of Fig. 1 but the stretch of the belt should be cross-wise instead of lengthwise. This is readily accomplished by means of aconventional tentering device in which the opposite rows of pins or clamps holding the edgesof the elastic belt are caused to diverge during the forward. movement of afiixed belt and thereby stretch the belt in a cross-wise direction and maintain this relation until'the fabric has been adhered to the l5 belt, following which the opposite rows of pins or clamps are then caused to gradually converge to a parallel relation during the continuous forward motion of afllxed belt to release the crosswise tension on belt and thereby condense the fabric in the cross-wise direction. It-isto be understood that the adhesive may be applied'to the belt either before or after-stretching cross-wise by means of tentering device and that the subse-- quent steps of treating condensed fabric would then follow in the mannerpreviously outlined after cross-wise tension has been released as described in reference to Fig. 1.

If desired, belt Ill of Fig. 1 maybe stretched by a tenter frame in a cross-wise direction after it has been stretched in a lengthwise direction as by the pull rolls II and I6, and in such a case on retraction of the belt in both cross-wise and lengthwise directions after the fabric has been sufllciently adhered to the stretched belt, a'condensatlon of the fabric will occur both crosswise and lengthwise.

The removable adhesive may be applied to the belt in any desired pattern as by means of spaced or engraved rollers or a grooved or notched bar or knife instead of bya spreading or spraying operation and the fabric made to adhere'to the belt only at those parts where the adhesive has beeh applied in the desired design. In this way the fabric will be condensed only in those areas 4: which were adhered to thebelt and the finished elastic fabric will have a design by virtue of those portions of the fabric which were not adhered to the belt presenting a more or less crinkled or puckered appearance. a

Other methods than by thefutilization of glue or other temporary adhesive may be utilized to maintain the fabric in a condensed condition until after depositionof the rubber frbm the rubbercontaining fluid to set the fabric in the condensed condition. For example, the fabric may be treat-' ed with the rubber-containing fluid and before depositing the rubber from -the same to set the fabric, the thus treated fabric may be sandwiched on which belts are released before or while setting or depositing the rubber as by a' drying operation or by coagulation. In this case, the friction between the rubber belts and the fabric causes the fabric to condense.

It-is desired to point out that while the apparatus illustrated in Fig. 1 of the drawing is constructed to apply the rubber-containing fluid to the fabric 'after the fabric has been, condensed,

ing fluid may be applied to the fabric before the latter is condensed and then coagulated or vulcanized after the fabric is condensed to, yieldingly hold the fabric in the condensed or contracted condition. The use of rubber-containing fluid,

stretched portions of the belts and later as a permanent elastic binder is the subject matter of an application Serial No. 69,302 filed Marchl7, 1936, by Merwyn C. Teague and Thomas G. Hawley, Jr.

Figs. 3 and 4 illustrate the condensation of the textile fabric of Fig. 2 in a lengthwise direction, and in a widthwise direction, respectively. In Fig.

, 2 is shown a ribbed-knit textile fabric, the horizontal lines a of which representing the knitted courses of yarn in the under surface of the fabric widthwise of the material, and the vertical columns b representing the wales on an outer surface of the fabric, lengthwise of the material. Such a knitted textile fabric as shown in Fig. 2 has a considerable capacity to stretch cross-wise, that is in the direction of thecourses but very little 'capacity to stretch lengthwise in the direction of the wales.

When the fabric of Fig. 2 has been treated by the apparatus of Fig. 1, that is condensed in a lengthwise directionjand the fabric set in the condensed condition and made elastic by means of the rubber deposit, it will have the appearance of the fabric of Fig. 3. The capacity of the fabric to stretch in a widthwise direction, that is in the direction of greater stretchin the direction of the courses, is substantially unchanged. but the fabric has had imparted to it a considerable capacity to stretch in a lengthwise direction, that is in the direction of the wales where previously it had asmall or no capacity for stretching. The

condensing of the fabric lengthwise has produced 5 cording to the present invention and condensed in a widthwise direction as described above, it will have the appearance of the fabric of Fig. 4. The fabric remains-substantially incapable of stretching lengthwise in the direction'of the wales but the condensation of the fabric widthwise has substantially increased the amount of stretch possible in the direction of the courses by the amount of condensation of the fabric. Thus from a textile fabric having a capacity to stretch-in substantially only 'one direction has been produced an elastic fabric capable of stretching in the same direction but to an appreciably greater amount than before treatment; v

The appearance of the fabrics of Figs. 3 and 4 differ vastly from each other and from the fabric of Fig. 2 before treatment. In Fig. 3 the knitted courses a are still visible below the outer surface of the fabric but the loops are closer' together and the wales b have become somewhat zig-zag in appearance .due to the lengthwise condensation of the fabric. In'Fi'g. 4, the loops of the knitted course below the surface of the fabric 1 have become completely hidden behind the wales invention is applicable to woven and bias and net fabrics and on the constructions of the 'fabrics' and the direction or directions of condensation will depend the changes in appearance. The constructions of the uncondensed fabric shown in Fig. 2 and of the condensed fabric shown in first as an adhesive to secure the fabric to the Fig. 3 are shown in detail, respectively, in Figs. 5 and 6. It will be noted that when the fabric is condensed in the direction of the wales (as indicated by the arrows b) from the uncondensed condition shown in Fig. 5 to the condensed condition shown in Fig. 6, the courses a are moved closer together and the-heads c of the loops in the same course are moved along the necks d of the cooperating loops of such course and are spaced therefrom as indicated at e. The length of the loops extending between the courses are also shortened to such an extent that the filbers of the yarns are caused to buckle to such an ex tent that they separate from one another as shown in Fig. 7. A fabric condensed in accordance with the process described herein is further characterized by having all of the tension'released from the yarns extending in the direction in which it is condensed. Greater capacity for stretching results from the foregoing characteristics imparted to the fabric.

When the rubber backing or lamina consists of rubber deposited in situ, i. e., directly from a rubber containing fluid, it is grainless and has a uniform modulus of elasticity in all directions, and such rubber being applied in a fluid or pasty condition to the fabric an excellent bond is obtained. It is preferred to obtain the rubber lamina from rubber latex to obtain greater elasticity, better aging properties, and greater strength for a given amount of rubber. An elastic fabric thus constructed is provided with a uniform modulus of elasticity and is advantageous over a fabric having a grained rubber backing, such as is produced by calendering and whose modulus of elasticity is different in the direction of the grain from that in thetransverse direction.

As various other modifications will occur to those skilled in the art, it is not intended to limit .textile fabric and a lamina of rubber consisting of a grainless rubber deposit derived from an aqueous dispersion of rubber intimately bonded to the surface of said textile fabric in which the bond comprises vulcanized rubber, said textile fabric having yarns which are buckled in at least one direction and retained in such buckled condition by the contractive force of the rubber when unstretched.

2. A patterned elastic fabric comprising a layer of textile fabric having a coating 'of rubber bonded to said fabric and coextensive therewith, said textile fabric having some areas retained in a condensed condition by said rubber coating and in which the threads extending in one directio are crowded together and those extending in the transverse direction to the aforesaid threads are relaxed and buckled, and said textile fabric having other areas which are puckered.

3. A patterned elastic fabric comprising a layer of knitted textile fabric having a coating of rubber bonded thereto and coextensive therewith, said knitted fabric having some areas retained in a condensed condition by said rubber whereby the courses of said knitted fabric are crowded together and the heads of the loops are pushed back from the necks of their cooperating loops,

and said knitted fabric having other areas which are puckered.

MERWYN C. TEAGUE.

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