US2503024A - Decorative rayon fabric and method of making - Google Patents

Description

April 4, 1950 A. w. BoEsE Erm` nEcoRAnvEmYoN FABRIC AND METHOD oF MAKING Filed Fei. 2e, 1948 NN uN/O M MW NSMN Patented Apr.

UNITED STATES PATENT OFFICE 4.DECORATIVE RYlvlgC ANDMTHOD M n Alvin W. Boese, White Bear Township, Ramsey County, and Edward F. Michl, Lincoln Township, Washington County, Minn., assignors to Minnesota Mining & Manufacturing Company, St. Paul, Minn., a corporation of Delaware Application February 26, 1948, Serial No. 10,946`

Claims. 1

I 'I'his invention relates to novel non-woven` novel fabrication procedure. The invention provides fabrics suitable for use as Wrappers and as tying ribbons for de luxe gift packages, for use as floral wraps, for use as window drapes, and for use in decorating store window and counter displays, for example. The object is not merely to provide fabrics which are cheaper than woven rayonfabrics, but to provide decorative fabrics which are distinctive and have unique properties arising from their novel structure and the novel method of fabrication employed in making them.

The finished fabric has a ream weight (weight of 320 square yards) in the range of about 15 to 60 pounds, and consists essentially of a compacted mixture of thermoplastic cellulose acetate ilbers and non-thermoplastic viscose (regenerated cellulose) fibers, having a length of at least approximately one inch, the proportion of cellulose acetate fibers being about 40 to 65% by weight. The cellulose acetate bers are autogeneously interbonded at their crossing points of contact and constitute a network which holds in place the intermeshed viscose bers. The latter are not bonded to each other or to the cellulose acetate fibers but are held by mechanical restraint and frictional contact. These two types of fibers have individual physical properties which are peculiarly suited to the production of the present type of fabric having the desired properties.

As a consequence of subjecting the fabric web to lengthwise drawing tension and elongation during the fabricating procedure, in the manner hereafter described in more detail, a crosswise contraction of the ber network is secured which condenses the structure by turning and crowding the fibers, and which aligns the fibers in a direction lengthwise of the web. The alignment of the fibers results in the fabric having a high sheen. The area is reduced and the ream weight is increased, since the elongation produced by the stress is proportionately less than the crosswise 2 stress-strain properties which imparts highly desirable features. This can be readily ascertained by handling. If the-ends of a piece of the fabric are pulled in a lengthwise direction there is no appreciable springiness or elongation; and repetitive strong jerking produces snapping sounds, the feel and sound being similar to that of regular woven cloth. If the piece is then grasped at the sides and is firmly and steadily pulled crosswise it readily pulls out by at least about 20% without rupturing, and if the piece is then pulled in a lengthwise direction it contracts to restore the previous width. If lightly jerked between the hands, in a crosswise direction, there is a marked feeling of springiness due to stretch and elastic regain, and only a weak snapping sound can be produced. It can be pulled crosswise to a plainly visible extent without the elastic limit being exceeded. The alignment of the fibers also results in fabric having a greater lengthwise stiffness as compared to the degree of crosswise stiffness. as is readily apparent when the web is subjected to lengthwise folding and to crosswise folding.

This combination of the different lengthwise and crosswise properties results in the fabric having excellent draping qualities and a good feel. It has a cloth-like handJ Package tying ribbons can be readily tied with a firm or tight knot and resilient well-formed bows and" loops can be obtained.

The fabric of this invention can be readlb printed and dyed for obtaining various colorations and decorative effects. It'has a high wetstrength and can be washed. The wet-strength is also an advantage in the use of the product as a floral wrap since flowers are commonly wet or moist.

The method of making this new and useful fabric is briefly as follows:

A mixture of plasticized cellulose acetate fibers (about 40 to 65% by weight) and viscose bers, which each have a length of at least approximately one inch, is carded to form a continuous web. This carded web is then passed through a system of rolls which are adapted to produce an autogeneous interbonding of the thermoplastic cellulose acetate fibers by a combination of heating and soft pressing. The heating softens the cellulose acetate fibers suiciently to cause them to cohere and fuse at the points at which they cross each other. The softpressing is produced by roll surfaces which are soft and yieldable (as distinguished from the hard surfaces of calender rolls), and are set to produce a light pressure. The result is entirely different from that produced by pressing between hard surfaces, as the fibers are not bent or broken, and are not fiattened out or pressed into each other at the crossing points, but continue to overlie each other with but limited contact areas at the crossing points where autogeneously lnterbonded. Thus the integrity and continuity of each fiber is maintained throughout its length. This makes 1or high tensile strength and an absence of linting. It also is of great importance in the subsequent stage of fabrication in avoiding breaking of fibers under the strains involved. A typical single ply may have a ream weight of about pounds (weight of 320 square yards). For most purposes a multi-ply web is formed by laminating two or more single plies so as to increase the body and the tensile strength; the plies being autogeneously nterbonded by heating and soft pressing so as to interbond the contacting cellulose acetate fibers.

The carded and unified web is then moistened with water and passed between a pair of driven resilient squeeze rolls, and is then led over a series of supporting rollers to a second pair of driven resilient squeeze rolls which rotate somewhat faster than the first set, thereby subjecting the web to lengthwise drawing tension of the desired magnitude. The interposed supporting rollers are located in a tunnel having closed ends provided with apertures for the web to entei` and leave. A heated atmosphere, consisting of a mixture of steam and air, is provided in the tunnel. An illustrative temperature is 180 F. The steam prevents the moist web from drying out. The wet heating action softens both the viscose fibers and the cellulose acetate fibers and thereby facilitates the desired structural transformation. The bonds between the cellulose acetate fibers are not broken. An alternative procedure is to draw the web while immersed in hot water.

The tension on the web pulls the fibers in a lengthwise direction and also produces a substantia1 crosswise contraction of the fiber network whereby the bers are crowded and turned so as to increase the density of the web and align the fibers. The fiberscontinue to form a network and are not entirely forced into a strict parallel arrangement, but the lengthwise alignment effect is plainly visible.

The web leaving the second pair of squeeze rolls is led to a drying device, such as a series of heated drums, where it is dried, and is then wound in jumbo rolls. It is then slit and rewound into rolls of desired width and length.

This procedure lends itself to dyeing in the course of the operation. The web can be saturated with dye solution just -prior to the first squeeze rolls, and can be washed with water after leaving the steam tunnel, while en route to the second squeeze rolls. The steam tunnel serves to set the dye on the fabric.

The decrease in the width of the web serves as a convenient indicia of the degree of drawing tension exerted upon it during its travel between the two pairs of squeeze rolls. A drawing action sufiicient to decrease the width by about serves to produce to a plainly apparent and useful extent the structural alteration and change in physical properties previously described. A

' 4 greater drawing action may be used so as to decrease the width by 50% or even more but, in

. general, the most desirable reduction will be found in the range of 20 to 50%.

The drawing tension results in a lengthwise elongation which is but a fraction of the crosswise contraction. As an example in an illustrative case, a web was drawn so as to produce a crosswise contraction of about 30% but the elongation was only about 10%.

Other features and characteristics of the invention will be apparent from the following description.

In the accompanying drawing:

Fig.,1 is a diagrammatic elevation view showing illustrative apparatus for heating and softpressing a carded ber web to provide a compacted unified web preliminary to the drawing operation.

Fig. 2 is a diagrammatic elevation view showing illustrative apparatus for simultaneously dyeing the web and drawing it 'to provide, after drying, the finished decorative fabric ofthe invention.

Referring to Fig. 1, a carded fiber web 4 is shown coming from a carding machine (not shown) and being fed into the apparatus. The carding machine is not shown as it is not special equipment and such machines are well known. By a carding machine is meant not only those which are technically termed carding machines, but also garnett machines which operate to form carded webs. T'he carding procedure straightens out the bers and'forms a loose open-mesh fiufy web of interlaced fibers which pass over and under each other in a heterogeneous fashion. Each fiber is crossed by numerous other fibers along its length. An example of a suitable garnett machine for present purposes is one in which the working rolls have 22 teeth per inch, the finishing cylinder has 24 teeth per inch, and the finishing doffers have 28 teeth per inch. The mixture of cellulose acetate and viscose fibers can be prepared for carding by throwing the fibers, in the desired relative proportion, into a picker which blends the mixture and opens the fibers. The fiber mixture can be humidified or moistened to render it in best condition for carding. Exposure to a room atmosphere of 65% humidity properly conditions the fibers.

Heating of the carded web is produced by a polished steel drum l, rotated about a horizontal axis by an electric motor (not shown) The drum rotates in a clockwise direction in this view.

. This drum has a diameter of about 16 inches.

It is heated by electric heating elements mounted on a fixed spider or frame (not shown) located within the drum, but may of course be heated in any other suitable manner.

Pressing of the fiber web against the heating drum is produced by the soft rolls 2 and 3 which bear againstthe drum surface and are free to turn. Roll 2 is located so that it contacts the heating drum near its top, and roll .3 is spaced beyond, about one-fourth of the distance around the drum. These pressing rolls are each made of a. light sheet-metal-roll having a diameter of 5 inches upon which is wound heavy creped kraft towelling paper to form a soft and resilient base layer approximately 1,4; inch thick, and upon this is wound four turns of finely woven glass cloth having a smooth type surface, forming a cloth layer approximately My inch thick. The cloth is wound on in a clockwise direction and the outer end is left free so as to trail through the nip, preenough to produce the type of fiber interbonding herein described. In operation the softness of the roll results in a' peripheral contact distance of about 1/4 inch. An idea of the softness of 'the pressing operation can be gained from the fact that a large diameter pencil lead (0.085 inch di' ameter), mounted by means 'of adhesive tape on a piece of paper, can be passed through the nip 6 freely-turning wood guide roll l. located above and forwardly of the pressing roll. It then is drawn back to and between the nip of a pair of steel pull rolls and ill, which are driven in synchronism with the rotating heating drum by means of a chain drive (not shown) connected to the motor which drives the heating drum. The upper roll 9 is surfaced with heavy paper so'as to exert greater traction on the web. These pull rolls draw the web under tension from the second pressing roll, which results in holding it smooth'while cooling' down. The fully formed product then goesto the wind-up roll Il where it is' wound on a core. The wind-up roll is driven bythe rotating pull rolls through a slip-belt drive (not shown) whichA keeps it rotating at the 'correct'speed as the web is wound up.

without damage to the lead (the lead being Pajallel to the axis of the roll) A wooden dowel of 0.160 .inch diameter can be passed throug'h'th'e nip. This light-pressure soft-roll pressing action is entirely different from the pressure effect pro'- duced by the calendars used in textile mills, which have "hard rolls forming the nips through which sheet material is passed.

:The carded fiber web a carding or garnett machine to the present'ap'- paratus where it is drawn in at the nip between the heating drum I and the first pressing roll 2, where it is subjected to a first pressing to compact the fibers, and to heating in contact with the-polished surface of the heating drum. The vweb travels around on the surface of the rotating heating drum to and through the the heating drum and the second pressing roll I, by which time the thermoplastic fibers will all have been softened sumciently to insure proper interbonding. During the travel interval between the nips, the web is thus subjected to heating under slight tension but without being pressed.

4 is shown coming from nip between This'arrangement holds the web in smooth coni tact with the heating drum surface and prevents wrinkling or distortion. The drawing shows an arrangement by which the carded web 4 is simultaneously laminated to a previously formed single ply product of the ap-- paratus to form a unified product of double thickness and ream weight (two ply). A roll of previously made single ply'web I is mounted pn' a freek! turning mandrel 8 mounted above and 4to the back of the heating drum. This web is drawn forward and passes'down around the freely turning' guide roll 1, which is located directly above the first pressing roll 2, and then passes vertically downward to and around the roll 2 and enters the nip in contact with the underlying carded ber web 4, and travels in contact with the latter. The heating and pressing results in the bottom thermoplastic fibers of web 5 interbonding with the top fibers of the carded web 4, so that thetwo sheets become laminated together into an integral two-ply'web. This process can be repeated by using the two-ply web to form a three-ply united web by lamination to a fresh carded fiber web, and so on. However, a unified web of several piles thickness can be directly made by feeding in several carded fiber webs at once, in which case the'feeding in of a previously formed web (as shown in the drawing) will of course be omitted. The. bonded web in heated condition, having passed through the nip of the second pressing roll 3, is drawn up and around the latter roll and is thus separated from. the surface of the heating drum. It then passes to and around a Stripping of the bonded web from the heating drum is'facilitated by the air-jet I2, which is a horizontal'tube having a slit orifice and is located behind the n ip between the second pressing roll '3 'and the lheating drum I, so as to direct a vJet of compressed air toward the nip.

'light'pr'essing action, but not so high as to melt or flatten out these fibers at their crossing points or to cause the non-thermoplastic viscose-fibers to cnt into the thermoplastic fibers. It has been found in practice that the surface temperature of the heating drum should be in the range of 3 40-375 F.,' and a temperature not exceeding about 3 60" F. is preferred for best results.

The foregoing apparatus has been operated successfully at a speed such that vthe periphery of the heating drum, and the-web, move at a rate of 55 feet per minute, thus producing the unified product at the rate of 1100 yards'per hour.

Reference is now made to Fig. 2 which illustrates the further procedure used in making the fabric of this invention. The described procedure includes the dyeing of the fabric. The

entering web i5 is the unified fibrous sheeting resulting from the processing operation described in connection with Fig. 1. It is unwound from a stockLroll and passes over roll I6, then down to and around `rol1 I1, where it passes through dye bath II. 'I'he wet web then passes up to guide roller is and then over to a pair of driven squeeze rolls 2l and 2|, which have a diameter of six inches and the upper one of which is'rubbercovered to provide a resilient tractive surface, while the lower one has a steel surface. The squeeze rolls serve to remove excess dye solution and firmly hold the web against the drawing force exerted on' the leading portion as hereafter described.

The damp web then. passes into horizontal Vsteam tunnel 22, which is about ten feet long and is closed at each end except for entrance and exit apertures, and moves over a series of underlying driven conveyer rollers 23 which direct the web along an upward slope to the middie and then along a downwardA slope to the exit.

A steam-air atmosphere is maintained in the tunnel at a temperature of about F., to heat the fibers and prevent the web from drying out,

the nip of driven squeeze rolls 28 and 28, the upper one of which is rubber-covered. En route to these squeeze rolls, the web is washed twice with cold water, supplied by pipe 30 located above roll 25 and by spray pipe 3l located above the web where it enters the squeeze rolls. A catch basin 32 is located below the series of rolls.

The squeeze rolls 28 and 29 serve to remove excess water from the web and provide the drawing action upon the web, previously described, as the result of being driven so as to have a somewhat faster peripheral speed than the first pair of squeeze rolls and 2|, in consequence of which the web undergoes elongation and crosswise contraction, which mainly occurs during transit through the steam tunnel.

The damp web passes from the squeeze rolls to and through a bank of four screen-surfaced drying cylinders 33, 34, 35 and 36. which have a diameter of about 3 feet and are mounted in square fashion. Hot air at a temperature of about 250 F. is blown into the cylinders and passes out through the surfaces and the contacting web. The drying cylinders are contained in a housing (not shown) from which the moist exhaust air is withdrawn. The dried web then passes over guide roller 31 and goes to a wind-up roll 38 where it is wound in a stock r011. The winding tension maintains the web under tension as it is dried so as to properly set the fiber structure and produce an unwrinkled product. The web may of course be given one or more coating treaments such as is frequently done in textile finishing, as for example a waxing treatment or a fire-proofing treatment. Thus as the damp web moves from the squeeze rolls to the drying cylinders, a dilute wax emulsion may be licked on by coating rolls. As such optional operations are well understood they need not be illustrated or described in detail.

The above-described dyeing and washing steps are optional, but when a dyed fabric is to be made it will generally be most convenient to incorporate the dyeing procedure as an integral part of the described fabricating process. When dyeing is not employed, ordinary waterwill of course be used to wet the web before it enters the nip of the first pair of squeeze rolls (20 and 2l). A wetting agent may be included in the water to facilitate thorough wetting of the bers.

The foregoing apparatus for dyeing and drawing the fabric can readily be operated at a web travel speed of about 360 lineal yards per hour. The output can be increased by super-imposing two or three webs and subjecting them to simultaneous processing, and then winding them separately after drying. 1

A preferred fiber mixture for use in making decorative ribbons for gift packages is composed of plasticized staple cellulose acetate fibers of 3 denier size and 1.25 inch length, and staple viscose fibers of 1.5 denier size and 2 inch length, in approximately equal proportions by Weight. A two-ply unified carded web having a ream Weight of lbs. is prepared and is drawn sufficiently to reduce the web width by about in the finished fabric, which has a ream weight of about lbs. and a lengthwise tensile strength of about 15 lbs. per inch width. fabric can be readily slit and wound into ribbon rolls of desired Width and length.

Waxing the fabri'c (by applying a dilute wax emulsion before drying as previously mentioned) results in ribbon products which have somewhat improved workability in making fancy bows, but

fibers, such as ramie bers or wool, for example.

Other regenerated cellulose fibers can be used in place of viscose fibers to produce an equivalent result, even though not technically termed viscose fibers.

What we claim is as follows:

1. A method of making a decorative non-woven rayon fabric by transforming the structure of a continuous compacted carded web sheeting essentially consisting of mixed staple cellulose acetate fibers and staple vicose fibers which both have a length of at least approximately one inch, the acetate fibers being in the proportion of about 40 to 65% by weight and being autogeneously interbonded at their crossing points to form a network within which the viscose fibers are distributed, the fibers substantially completely retaining their integrity and uniformity throughout their length and the intermeshed viscose fibers being unbonded and held only by mechanical restraint and frictional contact, said web having a ream weight which will produce a nished fabric having a ream weight in the range of about 15 to 60 pounds; which method comprises subjecting the aforesaid continuous fiber web to drawing under lengthwise tension while in a moistened and heated condition, without disrupting the acetate fiber interbonding, and subsequently drying the web while still under tension to set the altered fiber structure, said drawing being sufficient to reduce the width of the web by about 20 to 50% and turning, crowding, and aligning the fibers, and increasing the lengthwise tensile strength and the ream weight of the web; the recited method serving to form a decorative rayon fabric sheeting have a ream weight in the range of about 15 to 60 pounds, having a high sheen and markedly different lengthwise and crosswise stress-strain and stiffness properties, having a springiness when lightly jerked crosswise and an ability to be pulled out crosswise by at least 20% without rupturing and thereafter to be restored by lengthwise tension, but producing a cloth-like snapping sound and feel when strongly jerked lengthwise, and having a cloth-like hand. I

2. The method of claim 1 wherein the ber web is subjected to the drawing tension while passing through a tunnel containing a steamair atmosphere and while supported by rollers therein.

3. 'I'he method of claim 1 wherein the fiber web is first saturated with dye solution and then in damp condition is subjected to the drawing tension while passing through a tunnel containing a steam-air atmosphere and while supported by rollers therein, so that the dye is set on the f'lbers, and then while still under 'tension is washed prior to the step of drying.

k1. As a new article of manufacture, the decorative non-woven rayon fabric made by the procedure specified in claim 1.

5. A roll of decorative gift wrap tying ribbon slit from the novel fabric made by the procedure specified in claim 1 and Wound upon itself, and further characterized by the acetate and viscose bers being in approximately the same proportion by weight and the ream weight of the ribbon being of the order of 35 pounds, said ribbon tying 9 Y with 'a hard knot and providing resilient wellformed bows and loops.

ALVIN' W. BOESE. EDWARD I". MICHL.

REFERENCES CITED The following'references are ofA record in the A lerof this Ipatent:

UNITED STATES PATENTS Number Name Date Buhlmann Dec. 30, 1930 Sease May 3, 1932 Hickman June 18', 1935 Number l0 e Name Dato Lane Dec. 29, 1936 Dreyfus Aug. 16, 1938 Schneider Aug. 16. 1938 Bowen Sept. 20, 1938 Platt Jan. 9, 1940 Wallach Aug. 19, 1941 Reed Mar. 24, 1942 Schneider Mar. 9, 1943 Francis Sept. 5, 1944 Reed Sept. 19, 1944 Playford Mar. 6, 1945 Goldman Sept. 10, 1946

Claims (1)

1. A METHOD OF MAKING A DECORATE NON-WOVEN RAYON FABRIC BY TRANSFORMING THE STRUCTURE OF A CONTINUOUS COMPACTED CARDED WEB SHEETING ESSENTIALLY CONSISTING OF MIXED STAPLE CELLULOSE ACETATE FIBERS AND STAPLE VICOSE FIBERS WHICH BOTH HAVE A LENGTH OF AT LEAST APPROXIMATELY ONE INCH, THE ACETATE FIBERS BEING IN THE PROPORTION OF ABOUT 40 TO 65% BY WEIGHT AND BEING AUTOGENEOUSLY INTERBONDED AT THEIR CROSSING POINTS TO FORM A NETWORK WITHIN WHICH THE VISCOSE FIBERS ARE DISTRIBUTED, THE FIBERS SUBSTANTIALLY COMPLETELY RETAINING THEIR INTEGRITY AND UNIFORMITY THROUGHOUT THEIR LENGTH AND THE INTERMESHED VISCOSE FIBERS BEING UNBONDED AND HELD ONY BY MECHANICAL RESTRAINT AND FRICTIONAL CONTACT, SAID WEB HAVING A REAM WEIGHT WHICH WILL PRODUCE A FINISHED FABRIC HAVING A REAM WEIGHT IN THE RANGE OF ABOUT 15 TO 60 POUNDS; WHICH METHOD COMPRISES SUBJECTING THE AFORESAID CONTINUOUS FIBER WEB TO DRAWING UNDER LENGTHWISE TENSION WHILE IN A MOISTENED AND HEATED CONDITION, WITHOUT DISRUPTING THE ACETATE FIBER INTERBONDING, AND SUBSEQUENTLY DRYING THE WEB WHILE STILL UNDER TENSION TO SET THE ALTERED FIBER STRUCTURE, SAID DRAWING BEING SUFFICIENT TO REDUCE THE WIDTH OF THE WEB BY ABOUT 20 TO 50% AND TURNING, CROWDING, AND ALIGNING THE FIBERS, AND INCREASING THE LENGTHWISE TENSILE STRENGTH AND THE REAM WEIGHT OF THE WEB; THE RECITED METHOD SERVING TO FORM A DECORATIVE RAYON FABRIC SHEETING HAVE A REAM WEIGHT IN THE RANGE OF ABOUT 15 TO 60 POUNDS, HAVING A HIGH SHEEN AND MARKEDLY DIFFERENT LENGTHWISE AND CROSSWISE STRESS-STRAIN AND STIFFNESS PROPERTIES, HAVING A SPRINGINESS WHEN LIGHTLY JERKED CROSSWISE AND AN ABILITY TO BE PULLED OUT CROSSWISE BY AT LEAST 20% WITHOUT RUPTURING AND THEREAFTER TO BE RESTORED BY LENGTHWISE TENSION, BUT PRODUCING A CLOTH-LIKE SNAPPING SOUND AND FEEL WHEN STRONGLY JERKED LENGTHWISE, AND HAVING A CLOTH-LIKE "HAND."

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