US2613522A

US2613522A - Apparatus for treating fabrics and uncurling the edges thereof

Info

Publication number: US2613522A
Application number: US115680A
Authority: US
Inventors: Robert D Heffelfinger
Original assignee: American Viscose Corp
Current assignee: Akzo Nobel UK PLC
Priority date: 1949-09-14
Filing date: 1949-09-14
Publication date: 1952-10-14
Anticipated expiration: 1969-10-14

Description

1952 R. D. HEFFELFINGER 2,613,522

APPARATUS FOR TREATING FABRICS AND UNCURLING THE EDGES THEREOF Filed Sept. 14, 1949 Q INVENTOR. 9 Ross/r7 0. HEF'FELFINGER BY x214 g ATTORNEY.

Patented Oct. 14, 1952 APPARATUS FOR TREATING FABRICS AND UNCURLING THE EDGES THEREOF Robert D. Heffelfinger, Lansdowne, Pa., assignor to American Viscose Corporation, Wilmington, Del., a corporation of Delaware Application September 14, 1949, Serial No. 115,680

8 Claims.

This invention relates to an apparatus for handling :tricot fabrics..

Tricot fabrics areproduced on conventional tricot Warp-knitting machines by linking or looping the yarns together on the needles through guides arranged on guide; bars which traverse the desired distance'fromleft to right. The fabric is removed from the knitting machine in flat condition. Howeventhe flat condition is temporary. During the knitting; the yarns are subjected to stresses incidental to the looping operations, and strains are set up in the fabric. Since the strains at one face of the fabric are greater than at the other, the tendency of the yarns to assume a balanced condition inthe fabric, in opposition to the strains,-.r.esults in spontaneous rolling or curling of the fabric edges. The fabrics are usually treated with hot liquids as a step in their preparation forthemarket. For example, the fabrics are dyedin a-heated dye bath. These wet-finishing treatments are complicated by the rolled or. curled condition of the fabric edges. 'Iricot fabrics which comprise yarns of a fiberforming material whichis thermoplastic or activatable by heat to a softenedcondition not only undergo spontaneous edge-rolling as soon as they are taken from the knitting machine, but also acquire wrinkles.- or .crows feet when they are treated with a hot; liquid. .The wrinkles or creases are set intthefabric by the heat and cannot be removed bygpressing or ironing the fabric.

The tricot fabrics cannot be dyed or otherwise wet-processed satisfactorily in the openconditionif the edges areflcurled, and thecommon commercial practiceis to sew the edges together, prior to dyeingthe fabric, and to then separate the edges'after the fabric has been dyed, rinsed, and .;dried.- The -.disadvantages of this practice areobvious. .3 r

The object of thisyrinventionis toprovide an improved tappar'atus Jfor-T-uncurling the edges of a tricot fabric and while maintaining the fabric in flat condition, permanently relieving the strains which'induce. edge-rolling, thereby eliminatingthe tendencyiof the-edges. to roll, and stabilizing the fabric in -the flat condition, prior to dyeing or otherwise wet-finishing the fabric.

In accordance with the invention, the edges of the fabric are uncurled and the uncurled fabric is stabilized by passing it through a relaxing liquid which swells'or softens the yarns without converting them to a tacky or adhesive condition, iflthe yarns are of x the; solvent-activatable type, -or which is heated" to a temperature at fabric advancing to the relaxing liquid are uncurled by subjecting them to liquid projected under pressure against the edges, at successive points along the path of travel of the fabric to the relaxing liquid, and after the fabric has entered the relaxing liquid.

In one aspect, the invention comprehends a vessel for containing the relaxing liquid, means for guiding the fabric through the liquid and preventing curling of the edges during its passage through the liquid, means for continuously advancing the fabric in a substantially tensionless condition to and through the liquid, and means for projecting liquid under pressure against the opposite edges of the fabric, which means extend from a point in advance of the vessel into the vessel and terminate below the level of the liquid in the vessel adjacent the means for guiding the fabric through the liquid.

The novel features of the invention will appear more fullyhereinafter from the following detailed description when taken in conjunction with the accompanying drawing, in which Figure 1 is a view in perspective of apparatus in accordance with the invention; and

Figure 2 is a section taken on line II --II of Fig. 1.

Figure 3 is an elevation partly in section showing a modification.

Referring to the drawing, there is shown a vessel 2 provided with a removable cover 2a and containing liquid in which the yarns of the fabric swell and soften without being converted to a tacky or adhesive condition. Two guide plates 3 and 4, are supported in the vessel. The Width of the plates corresponds to the width of the fabric andthe plates are disposed one above the other, in spaced relation, to provide a guideway or tunnel 5 of substantially uniform cross-section for the fabric below the level of the liquid. The distance between the adjacent flat surfaces of the plates is suflicientto' permit free passage of the fabric therebetween, but insufficient to allow curling or rolling of the fabric edges. This distance may be varied, de-

ending on the thickness of the fabric. The opposite ends of plate 3 are curved or flared up wardly, and the opposite ends of plate 4 are curved or flared downwardly, to faciiltate feeding of the fabric to the space between the plates and withdrawal of'the fabric from the vessel, and to prevent drag or undue tension on the fabric as it is advanced through the liquid.

The tricot fabric having curled or rolled edges is advanced to vessel 2 over the driven feed roll downwardly over the inclined guiding surface '1, fed between the plates 3 and 4, and withdrawn from vessel 2 by the driven withdrawing rolls 8 and 9, a roll 8a being supported between the withdrawing rolls. As shown, the guiding surface "i is a flat plate-like member and both it and the guide plates 3 and i are made of any suitable material, preferably a polished metal such as stainless steel. Guiding surface 1 extends into vessel 2 and is fixed in inclined relation to feed roll 6 andguideway or tunnel 5 between plates 3 and 4.

In order to uncurl the edges of the fabric and maintain the fabric in the flattened condition until it enters the guideway 5 between plates 3 and 4, jets of liquid are projected against the opposite edges of the fabric at successive points along the path of travel of the fabric downwardly over guiding surface 1 to guideway 5, at least two, and preferably three of the liquid jets being projected against each of the fabric edges below the level of the liquid in the vessel 2. For this purpose, and as shown in the drawing, two pipes or conduits ii] and H, each provided with a row of perforations i2, are supported above and parallel to the guiding surface I, on the cross bars 13 and 'l 4 which are in turn supported on the standards I5, is and ll, 18. Pipes l8 and H are adjustable horizontally on the cross-bars l3 and I4 by adjustment of the clamps or brackets designated generally at It, and cross-bars l3 and If are adjustable vertically on the standards l5, l6 and I1, l8, respectively, by adjustment of the clamps or brackets designated generally at 2%. Pipes it and i i diverge in the direction of travel of the fabric and extend into vessel 2, terminating below the level of the bath, immediately adjacent the entrance to guideway 55.

It is important that the maximum uncurling force of the liquid jets be applied against the fabric edges, and to insure this, the perforations E2 in pipes ill and Ii are drilled at an angle in clined from a right angle to the pipes such that the resultant of a velocity polygon illustrating the relation of the speed of the travelling fabric to the speed of the liquid jets extends in a direction inclined slightly forward of a right angle to the longitudinal axis of the travelling fabric, regardless of the speed at which the fabric travels or the angle of divergence of pipes l8 and I I. The liquid jets strike the fabric edges in a slightly forward direction, the angle between the guiding surface and a jet, measured in a plane containing the jet and extending at right angles to the guiding surface 7, being, generally, from 10 to The angle of divergence of pipes l0 and l I must be selected so that the liquid jets emerging from the perforations 12 will not overshoot the edges of the fabric. In general, this angle of divergence is selected so that the distance between the points at which the liquid jets first strike against the opposite edges of the fabric is about twelve inches less than the width of the curled fabric, while the distance between the points at which the jets strike against the fabric in the vicinity of guidemay be modified in certain respects.

way 5 is about twelve inches less than the width of the uncurled fabric, when the angle between the guiding surface and a jet, measured in a plane containing the jet and extending at right angles to the guiding surface 1, is from 10 to 20. As shown, some of the liquid jets are projected against the edges of the fabric after the fabric has entered the relaxing bath. This is critical, since a slight suction is created in guideway 5, by passage of the fabric into and along the guideway, with consequent lowering of the bath level at the entrance to the guideway and the creation of turbulence in the bath which may effect recurling of the edges if such recurling is not posi-- tively prevented. The jets of liquid projected against the fabric edges below the level of the bath prevent recurling of the edges before the fabric is introduced into the guideway 5. The arrangement of the pipes, and the distribution of the perforations in the pipes, are such that the opposite edges of each succeeding portion of the fabric entering guideway 5 are subjected to a jet of liquid. This not only prevents recurling of the edges at the entrance to the guideway but also facilitates feeding of the fabric to the guideway. The fabric floats through the guideway 5 in a substantially straight-line path.

In practicing the invention, it is preferred to uniformly wet-out all portions of the fabric before it is introduced into the relaxing bath. As shown, a pipe or conduit 2| supported on the

standards

22 and 23 extends above and transversely of guide plate 1 and is provided with perforations 24 through which liquid is sprayed on the fabric. This shower of liquid facilitates continuous movement of the fabric over the surface of the inclined guide plate 1, thus minimizing or eliminating localized tension spots which occur in the fabric if it is allowed to stick to the plate I, insures uniform wetting of all portions of the fabric, and prevents marks which are particularly noticeable in the finished fabric if the edges of the fabric are softened before the remaining portions of the fabric have been uniformly wet.

It is desirable to arrange the guide plates 3 and 4 in vessel 2 so that the distance from the level of the bath to the guideway 5 is such that undue turbulence at the entrance to the guideway is avoided, and any cooling at the surface of the bath is not transmitted to the liquid in the vicinity of the guideway. Arrangements in which the distance from the level of the bath to the guideway is at least two inches are satisfactory.

Under the action of the relaxing liquid, the strains in the fabric are relaxed, with softening of the yarns, and contraction of the fabric as a whole. It is essential for the fabric to pass through the relaxing liquid in a substantially tensionless condition, in order for the shrinkage which accompanies swelling and softening of the yarns to take place without subjecting the fabric to a tension which would distort the stitches and impart a sleazy feel to the fabric. The rate at which the fabric is fed to the relaxing bath is correlated with the rate at which it is withdrawn from the bath to permit complete relaxation of the strains and contraction of the fabric. The fabric is advanced to and through the liquid in substantially tensionless condition.

The apparatus illustrated in Figures 1 and 2 For instance, as shown in'Figure 3 the guide plates 3 and .4 may be replaced by a pair of endless bands or belts 35 arranged one above the other g in spaced relation and supported on suitable pulleys 36 for travel in the direction of travel of the fabric. Also, guide plate 4 may be dispensed with, a single plate 3 being used. Any of these arrangements may be employed, so long as the fabric is passed through the liquid in a substantially straight-line path, without being subjected to contact pressure. Contact pressure must be avoided in order to prevent marking of the fabric While the yarns are, in swollen or softened condition.

Any liquid which has a swellingand softening action on the yarns of the fabric or which is maintained at a temperature at which the yarns are swollen and softened, may be used as the relaxing liquid, provided the liquid does not activate the yarns to a tacky or adhesive condition in the time required to stabilize the fabric, if the yarns are thermoplastic or heat-activatable to softened condition at thetime of treatment. In the preferred embodiment of the invention, when the yarns are thermoplastic or heat-activatable to softened condition at the time the fabric is stabilized, a relaxing liquid heated to a temperature at which the yarns are swollen and softened but below the tacky point of the yarns is used and means (not shown) is provided for maintaining the liquid at the preselected temperature. Any suitable means for maintainin the temperature constant may be associated with vessel 2, such as electrical heating coils, a jacket in which hot water or other heating fluid is circulated, etc.

As an example, hot water or any other nonsolvent for the yarns is a. satisfactory relaxing liquid for fabrics comprising yarns formed from cellulose acetate; the vinyl resins, for example resinous'fiber-forming copolymers of vinyl chloride with vinyl chloride or vinyl cyanide; polyethylene; nylons; fiber-forming polyesters from dicarboxylic acids and polymethylene glycols such as polymeric polymethylene terephthalates; fiberforming arclyonitrile polymers including polyacrylonitrile and copolymers or interpolymers of acrylonitrile with other polymerizable ethylenically unsaturated substances containing a major proportion of acrylonitrile in the polymer molecule, such as copolymers of acrylonitrile with vinyl acetate, the vinyl pyridines, styrene, isobutene, etc. The temperature of the water will depend on the softening point of the yarns and is below the tacky or adhesive point for the yarns. For example, water at 100 C. is satisfactory for fabrics comprising commercial cellulose acetate.

Preferably, when the relaxing bath is heated, in order to avoid unfavorable affects on the fabric which may result if the fabric is subjected to abrupt change in temperature, all portions of the fabric are preheated to the temperature of the relaxing bath, prior to introducing the fabric into the bath. The fabric may be preheated in various ways. However, in the preferred embodiment of the invention, the fabric is preheated to the bath temperature by spraying the fabric and uncurling the edges thereof with liquid circulated from vessel 2. The liquid is withdrawn from the vessel by pump 25 into conduit 26. Valve 21 is adjusted so that a portion of the Withdrawn liquid is diverted to pipe 2| through the flexible connection 28, and the remainder of the liquid is delivered to pipes l0 and II through the T-connection 29. Suitable means, such as heating coils, may be provided on pipe 26 for maintaining the liquid circulated to pipes [0, H and 2| at the temperature of the liquid in vessel 2, if desired, but usually are not necessary.

-ably a heatedaqueous sodium hydroxide solution.

Solutions of less than mercerizing strength may be used, to avoid a mercerizing effect where such effect is undesirable.

The treating time may be varied and may be, for example,from 3 to 24 seconds, when the fabric is a cellulose acetate fabric and the relaxing bath comprises water at C.

The fabric withdrawn from the heated relaxing bath is preferably sprayed with cold water or other non-solvent for the fiber-forming material, a pipe 30 provided with perforations 3| being supported above the withdrawing roll 8 for this purpose. The water or other cooling liquid is caught in a separate compartment 32 of vessel 2. The cold water treatment facilitates handling of the fabric and sets the fabric in the fiat, stabilized condition.

Tricot fabrics treatedin accordance with the invention remain in the fiat smooth condition until they are permanently shaped to tubular or three-dimensional form. The stabilized fabric may be dyed or otherwise processed as desired in'the flat condition, without rolling of the edges, and, in the case of fabrics knitted from yarns of a thermoplastic material, or a material which is activatable by heat to a softened condition, without wrinklin during hot-processing. Since the edges of the fabric are flat and do not curl spontaneously after the fabric is withdrawn from the relaxing bath, the fabric can be dried close to the edges, thus saving fabric, and the fabric emerges from the dryer with a straight course edge. The stabilized tricot fabrics have an improved feel and appearance as compared to ordinary tricot; fabrics.

Since some changes and modifications can be made in the above details Without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited thereto except as set forth in the appended claims.

I claim:

1. Apparatus for uncurling the edges of a fabric having curled edges and stabilizing the fabric in fiat, uncurled condition comprising, in combination, a vessel for containing a relaxing liquid for the fabric, guiding means supported in the vessel and defining a substantially straight-line path for the fabric through the vessel below the level of the liquid therein along which the fabric travels freely in the absence of contact pressure, said guiding means being at least as wide as the flat fabric and arranged to prevent curling of the edges of the fabric, a guide plate supported in inclined relation to the guiding means in the vessel and extending from outside the vessel to the entrance of the path defined by the guiding means in the vessel, means for continuously feeding a fabric warpwise downwardly over the inclined guide plate to the vessel and for drawing the fabric along the path defined by the guiding means and from the vessel in a substantially untensioned condition, a pair of conduits which diverge in the direction of travel of the fabric arranged above and parallel to the guide plate and extendin to the entrance to the path defined by the guiding means in the vessel, said conduits being provided along their length with spaced perforations at least one perforation in each conduit being adjacent to the entrance to the path defined by the guiding means in the vessel, and means for projecting liquid under pressure through the perforations outwardly from the conduits against the opposite edges of the fabric advancing over the guide plate and into the path defined by the guidingmeans in the vessel.

2. Apparatus as in claim 1, and including means for continuously withdrawing liquid from the vessel and circulating the, withdrawn liquid to the diverging perforated conduits.

3. Apparatus as in claim 1, and including a perforated conduit supported above and transversely 0f the guide plate.

4. Apparatus as in claim 1, and including a perforated conduit supported above and transversely of the guide plate, and means for continuously withdrawing a liquid from th vessel and for circulating a portion of the Withdrawn liquid to the perforated diverging conduits and for circulating the remaining portion of the withdrawn liquid to the perforated conduit arranged above and transversely of the guide plate.

5. Apparatus as in claim 1, wherein the guiding means defining the substantially straightline path for the fabric through the liquid in the vessel comprises a pair of substantially fiat plates supported one above the other, the distance between the plates being not substantially greater than the thickness of the fiat fabric passing therebetween, whereby the fabric passes freely between the plates and curling of the edges thereof is prevented.

6. Apparatus as in claim 1, wherein the guiding means defining the substantially straightline path for the fabric through the liquid in the vessel comprises a pair of endless driven bands supported one above the other in spaced relation for travel in the direction of travel of the fabric, the distance between the opposed surfaces of the bands being not substantially greater than the thickness of the flat fabric passing therebetween, whereby the fabric passes freely between the bands and curling of the edges thereof is prevented.

7. Apparatus as in claim 1, the perforations in said diverging conduits extending in a direction pointing downwardly and outwardly with respect to the pair of conduits at an angle inclined from a right angle to the conduits such that the resultant of a velocity polygon projected on the travelling fabric and illustratin the relation of the speed of the travelling fabric to the speed of the jets issuing from the perforations extends in a direction slightly forward of a right angle to the longitudinal axis of the travelling fabric.

8. Apparatus as in claim. 1, the perforations in said diverging conduits extending in a direction pointing downwardly and outwardly with respect to the pair of conduits at an angle such that the angle between the guide plate and any one of the liquid jets, measured in a plane containing the jet and extending at right angles to the guide plate, is between 10 and 20.

ROBERT D. HEFFELFINGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 956,550 Todd May 3, 1910 1,912,446 Remington June 6, 1933 1,913,601 Lepin June 13, 1933 1,935,637 Juer Nov. 21, 1933 1,997,267 Remington Apr. 19, 1935 2,157,118 Heckert May 9, 1939 2,267,117 Mann et a1 Dec. 23, 1941 2,308,511 Hilliard Jan. 19, 1943 2,313,173 Schneider Mar. 9, 1943 2,346,208 Conaway Apr. 11, 1944 2,361,371 Hanson Oct. 3 1944 2,365,931 Benger Dec. 2 19M