US3837998A - Stable band consisting of sized staple fibers and possessing high lengthwise stability - Google Patents

Abstract

A STABLE BAND POSSESSING HIGH LENGTHWISE STABILITY WHEREIN THE ELASTIC ELONGATION OF THE STABLE BAND, COMPARED TO ONE IN WHICH BINDING OCCURED IN A TENSION-FREE STATE, IS SEVERAL TIMES SMALLER.

Description

' 2 Sheets-Sheet 1 v WISE STABILITY w. NAEGELI.

AND POSSESSING HIGH LENGTH Filed larch 13, 19 '7- 0 oiskm'ssioil Sept. 24, 1914 Original Fig. 8

STABLE BAND-GONSISTING OF SIZED STAPLELFIBERS w. NAEGELI 3,837,998

AND POSSES SING HIGH LENGTHWISE STABILITY.

Original Filed larch 13, 1970 United States Patent US. (:1. 161-170 2 Claims ABSTRACT OF THE DISCLOSURE A stable band possessing high lengthwise stability wherein the elastic elongation of the stable band, compared to one in which binding occurred in a tension-free state, is several times smaller.

CROSS-REFERENCE TO RELATED CASE The present application is a divisional application of my commonly assigned, co-pending US. application, Ser. No. 19,243, filed Mar. 13, 1970, and entitled Method of Producing a Stable Band Consisting of Sized Staple Fibers of High Lengthwise Stability and Stable Band Produced According to the Aforesaid Method," now Pat. No. 3,770,538.

BACKGROUND OF THE INVENTION The present invention concerns a new and improved stable band consisting of adhesively interconnected staple fibers and possessing high lengthwise or longitudinal stability.

In spinning processes it is already known to produce stable bands consisting of staple fibers by means of treating or impregnating a suitably prepared untwisted strand of staple fibers with an excess of adhesive distributed in a liquid, with the surplus liquid being squeezed off and the fibers mutually compressed in a pressure zone. Further, the staple fibers are compressed into a compact band and by drying transformed into a stable band possessing sufficient lengthwise stabilization for undergoing a drafting operation. As a measure for judging the lengthwise stabilization the slope of the force-elongation curve of a band is chosen. Such stabilized bands exhibit that much better drafting properties for a subsequent drafting operation in a drafting arrangement, the higher the lengthwise stabilization of the stable bands is chosen. Since the average drafting force exerted upon a stable band subjected to a drafting operation is not constant, the band gripped in the nip of the drafting rolls of a drafting arrangement is subject to varying elongation, which, if a certain value is exceeded, can cause drafting waves. By producing suificiently lengthwise stabilized stable bands it is largely possible to eliminate these feared drafting waves which occur during drafting of normal twisted rovings and to produce yarns of good uniformity.

SUM-MARY OF THE INVENTION Accordingly, it is a primary object of the present invention to improve the elastic properties of a stable band in the drafting arrangement by a further degree or steps by means of a further increase of the lengthwise stabilization, that is, by considerably increasing the slope of the force-elongation curve in the force-elongation diagram in order to reduce the elongation of the band, when subjected to a certain average drafting force, to such an extent that it becomes negligibly small and no longer can influence the drafting operation. In this manner production of very even yarns can be achieved.

3,837,998 Patented Sept. 24, 1974 A further object of the present invention is to be seen in substantially maintaining the band structure established by compressing in the wet state during the subsequent treatment until the adhesive binds, and in effectively stabilizing the band in this compressed shape, which is of particular importance in processing fibers showing marked bulking tendency.

Now, in order to achieve these and still further objects of the invention, which will become more readily apparent as the description proceeds, the invention contemplates forming a stable band composed of adhesively interconnected staple fibers of high lengthwise stability by means of treating with an excess of liquid in which an adhesive is distributed, then squeezing off the liquid surplus, and compressing the fibers by applying pressure into a compact band in which the adhesive binds, and by application of tensile force the band is subjected to an elongation within the limits of elastic deformation while binding of the adhesive takes place.

A further aspect of the invention is characterized in that, the band after being compacted or compressed and before binding of the adhesive takes place, is subjected to an elongation within the limits of elastic deformation.

Furthermore, binding of the adhesive induced by drying can be effected at the highest possible temperature.

The stable band of high lengthwise stability produced according to the inventive method is manifested by the features that its elastic elongation is several times smaller than a fiber band in which binding of the adhesive occurred in a tension-free state.

BRIEF DESCRIPTION OF THE DRAWINGS tion of the continuous process for treating staple fiber bands.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now the invention, a staple fiber band produced by a suitable preparatory machine, e.g. by a card, is treated in a known manner with an excess of liquid in which an adhesive is distributed. By squeezing off the liquid surplus and compressing the band there results a compact, smooth but still wet staple fiber band containing a certain amount of adhesive, the bonding or binding of which has not yet taken place. This band already exhibits elastic properties under tension, that is, such band can be tensioned closely up to its wet breaking strength without sufiering permanent deformation. Such bands are now elongated within the limits of elastic deformation before, or at the beginning of, the bonding or binding of the adhesive by means of applying tension which is below the Wet breaking strength of said bands. This tension may be kept constant during the bonding process or may be varied within the limits of elastic deformation according to certain parameters or functions, for example, in order to take into account the changing length of the fibers during binding of the adhesive. The band also may be elongated by tens-ion before binding takes place and its length may be maintained constant while binding occurs, in which case the elongation is subject to changes according to the magnitude of the tension generated by the shrinkage which develops. Care must be taken in this case, however, that the band in its wet, partially or fully bonded state, is not over-elongated which would cause band breakage.

The inventive method can be carried out in a discontinuous process as well as in a continuous process. In discontinuous processing certain lengths of condensed, wet bands are laid out or suspended in tension-free state and then are tensioned by elastically elongating to a certain degree, and in this state are subject to a binding process. Binding of the adhesive, as a rule, is induced by extraction of the liquid, e.g. a solvent, most simply merely by drying. Binding, however, may be also induced by radiation, ionization or through the action of suitable gases, depending upon the adhesive used.

More explicitly, the discontinuous processing technique is described with reference to the following Examples I to III in which the band is tensioned to a certain degree before binding takes place, short band lengths being chosen solely for measuring purposes, from which band lengths short lengths of yarn only could be spun. In practice, a length corresponding to at least a usual package creeled on a ring spinning frame would have to be chosen. In the following Example binding is induced by drying, that is, extraction of the solvent by evaporation.

Example I A carded cotton of (American province) K.S. origin, of 1 staple length suitably prepared in a preparatory process, in a band weight of 1972 tex, is fed into a liquid applicator device, e.g. as described in Swiss Pat. 426,704 and is removed in the form of a compressed or compacted band. As treatment liquid there is used 7% aqueous solution of the commercially available starch derivative product Noredux 100, marketed by the Swiss firm, Blattmann & Co., of Wadenswil, Switzerland. A wet band of 1 meter length is cut from the band delivered by the liquid applicator device and is freely laid out horizontally. Drying took place without influence of any tension during 3 minutes at a constant temperature of about 80 C. In the dry state the band was clamped in a Tensile-Tester of the Instrom Company, Ltd., High Wycombe, Bucks, England, and the force-elongation diagram marked a in FIG. 1 was recorded. Another band prepared in the same manner was clamped in its wet state, a free length of 1 meter being maintained, and was elongated by 0.5%, which corresponds to an elastic deformation of the wet band of 5 mm. Subsequently, drying took place again during 3 minutes at constant length and at a temperature of 80 C. The force-elongation diagram as shown by curve b was recorded. In the same manner, a further wet band of 1 meter length was processed, elongation being increased to 1 percent. The force-elongation diagram obtained from this band is shown by curve 0. The resulting elongation percentages at a load force B=4 kg. are given in the following table:

Percent elonga- Percent tion elongaapplied tion in the of the wet; stable Curve state band 1 1 After binding, under load force B =4 kg.

Comparison of the elongation of the bands dried without tension and of the bands dried under tension shows a ratio of about 1:2 or better.

Example II firm, Polygal Co., Meerstetten, Switzerland. A 1 meter length of band was dried without tension at C. and its force-elongation curve a shown in FIG. 2 was recorded on the Instron Tensile Tester. Another piece of the same band was clamped in its wet state maintaining a free length of 1 meter and was elongated by 2% and was dried at 80 C. during 3 minutes. The resulting force-elongation diagram is shown in curve b. Similarly, a 1 meter length of the same band was elongated by 4%, clamped and dried, curve 0 resulting from this test. The elongation percentages as shown in the diagram, at a load force of 10 kg., are given in the following table:

Percent elonga- Percent tion elongaapplied tion in the of the wet stable state band 1 1 After binding, under load force B =10 kg.

Example III A 1972 tex band of highly crimped acrylic fibers of 53 mm. cutting length was fed into a liquid applicator device and was taken off as a compacted or compressed band. The treatment liquid was a 50% aqueous solution of the polyacrylate BAS-TX of the well known firm Badische Anilinund Sodafabriken, Ludwigshafen, Germany. Again, 3 band pieces each of 1 meter length were cut and dried at 80 C. during 3 min. with,

one being laid out without tension,

the second being pre-elongated by 2%, and

the third being pre-elongated by 5% and clamped, maintaining 1 meter clamping distance, and dried at 80 C. for 3 minutes.

The corresponding force-elongation diagrams are shown in FIG. 3. At a load force of 13:10 kg., the following elongation percentages are found:

Percent elonga- Percent tion elongation of the applied in stable Curve the wet state band 1 0 (tensionless) 12 Alter binding, under load force B =10 kg.

Thus, the elongation is 3.5 to 5.5 times smaller, which permits a considerable improvement of the lengthwise stabilization, and thus also of the draftability of highly crimped fibers.

From these examples it is evident that for an average drafting force, to which such bands are subject in the drafting zone, the elongation properties can be improved so decisively that the changes in length under the influence of the average drafting force, and thus of the numbers of fibers gripped in the nip of the front rolls, remains practically constant at each moment, resulting in excellent yarn uniformity. The discontinuous processing technique alternatively can be used by applying tensile load to the wet, condensed bands before and during the binding phase by exposing the bands to a constant tensile load causing Example IV A band as described in Example I is treated with a 5.5% solution of the cellulose derivative Solvitose X0 and Solvitose X1 (manufactured by Scholtens, Chemische Fabriken, Foxhal/Holland) mixed in the proportions 1 to 4, and is removed in the form of a compacted or compressed band; Wet bands of 80 cm. length are clamped at their upper end, suspended vertically, and are weighted at their lower end with weights of (for straightening only by slight tension), 150 and 300 grams respectively. Each band is dried in an air convector box for 8 minutes at 80 C. under the influence of the weights mentioned, and subsequently the force-elongation diagram is recorded on the Instron Tester. The resulting curves are shown in FIG. 4. The elongation percentages under a load force of B=4 kg. are given in the following table:

Percent Weight elon gaload tion in grams of the applied dried in the stable Curve wet state band 1 Under load force B=4 kg.

Example V A 1972 tex band of 1.5 den. Terylene fibers of 38 mm. cutting length was treated with liquid and taken off as a compressed band in the same manner as described in the preceding Examples. The treatment liquid used was a 30% aqueous solution of Vibatex S, a polyvinyl alcohol manufactured by Ciba Corp., Basel, Switzerland. During the 8 minute drying process at 80 C. the bands of 80 cm. length again were loaded with weights of 10', 150, 300, 450 and 600 grams respectively. The force-elongation diagrams shown in FIG. 5 resulting from the bands dried under the weight loads mentioned above, depict the elongation percentages at a certain load force given in the following table:

1 Under load force B=4 kg.

From this it is evident that already using relatively mod erate band tensioning, elongation can be lowered substan tially, i.e. that the drafting behavior of the bands can be improved considerably.

The lengthwise stabilization of the bands can be improved further in the case of binding, induced by supplying heat, i.e. drying, by using higher temperatures, as it was found that otherwise equally processed bands dried at higher temperatures show smaller elongation. The results show the same trend, no matter whether the bands are tensioned in the wet state and clamped, or whether they are loaded at their free end. The preceding Example V and the following Examples VI to VIII give a more detailed illustration.

Example VI The same example as in Example V was carried out, the only difference being that drying in the air convector box was carried out at a temperature of C. The force-elongation diagrams obtained from such bands are shown inFIG. 6. At a load force B=4 kg. the elongation percentage summarized in the following table are found:

Percent Weight elongaload tion in grams of the applied dried in the stable Curve wet state band 1 1 Under load force B=4 kg.

From these results it is evident that using the same band tensions at a higher drying temperature, a reduction of elongation can be achieved, which again results in improved lengthwise stabilization of the band which is favorable if the band is subsequently drafted.

Example VII Bands prepared as in Examples V and VI of 80 cm. length were elongated in the wet state by O, 1, 1.5, 2 and 2.5 percent respectively, and in this state were clamped at both ends. Drying then was effected at 80 C. The corresponding elongation percentages at a load force B=4 kg, as shown by the force-elongation diagrams of FIG. 7 recorded on the Instron Tester, are reduced according to the following table:

Percent Percent elonelongation gation of the applied in dried the wet stable state band 1 1 Under load force B =4 kg.

Here also a marked reduction in elongation percentages is noticed at the highest tension during drying.

Example VIII Percent Percent elonelongation gation of the applied in dried the wet stable state band 1 1 Under load force B =4 kg.

Comparison with the results of Example VII shows a further marked reduction in elongation percentages of the dried bands.

If the method is used in continuous manner, processing is effected as follows:

A compressed or compacted band 2 of staple fibers emerges from an applicator device 1 (FIG. 9) at the speed V and is transferred at the point A at a speed V =V helically onto a rotating drum 4 arranged in a housing 3 where it is subjected to a process inducing bonding of the adhesive. At point B, at the other end of drum 4, the band containing fiber mutually interconnected by the bound adhesive, now called stable band, leaves drum 4 and after passing through a traversing band guide is wound onto a band package 6. Binding of the adhesive occurs in the processing zone between the points A and B under a tension within the limits of band elasticity generated and maintained up to the departure point B. This tension can be adapted to requirements by choosing suitable diameter ratios of drum 4 insofar as the magnitude of the shrinkage of the stable band, depending upon a number of factors, such as type of fibers, temperature, duration of processing etc., must be taken into account. If, as in FIG. 9, a drum of constant diameter D=D is chosen, drying is effected while band length is maintained constant, i.e. the band is elongated elastically by the same amount as it shrinks during processing. If the drum diameter is reduced by means of choosing a slightly tapered drum shape (drum shown in dashed lines D D) elongation of the band on the drum is reduced. Diameter D however, should not be chosen so small that tension drops to zero. In analogy, diameter D of drum 4 can be increased (drum shown in dash-dotted lines, D D so that the band tension is increased somewhat. Diameter D should, however, not be increased so much that the limit of elastic elongation of the band is exceeded.

Using this method, continuous processing is achieved as opposed to the method used in the preceding examples, where processing was discontinuous. Transfer of the band to the subsequent winding device may be effected tensionfree or under tension, the band now being stabilized and its structure no longer being altered under the influence of tension, i.e. tension between the processing zone and the winding device may be chosen according to winding requirements.

In the continuous processing method there is the further possibility of choosing the circumferential speed V of drum 4 at point A higher than V so that also between said drum 4 and the liquid applicator device tensioning within the limits of elastic band elongation is effected. In this manner the compressed band 2 can not widen free of tension before reaching drum 4. The fibers also can not contract lengthwise due to their inherent crimp, nor effect mutual relative movements. Elongation thus will be chosen at least so large that fiber crimp straightened out by compressing cannot re-develop.

As a further alternative a method of continuous processing can be chosen in which the compressed band 7 (FIG. treated or impregnated with an adhesive distributed in a liquid is guided directly through a processing zone 8 and subsequently is wound onto a package 9. In the processing zone 8 the liquid is extracted. In this case the winding speed V in relation to the delivery speed V is chosen such, that the tension in the band 7, not yet stabilized, remains within the limits of elastic elongation in the processing zone 8 in spite of the fiber shrinkage.

The method makes use of the elastic deformation properties of the bands insofar as the band after the described treatment with liquid and compressing can be subject to tension without suffering a permanent change in length. In this manner the inherent fiber crimp cannot reverse the previously established band compression and binding occurs in the compressed state of the band.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Accordingly, what is claimed is:

1. A stable band composed of an untwisted arrangement of adhesively interconnected staple fibers and having high lengthwise stability, said stable band being stabilized by the staple fibers compressed into a compact untwisted band and bonded by a set adhesive material remaining in the band following compression, said stable band comprising said compact band having been elongated in its wet state within the limits of elastic deformation by application of a tension force while binding of the adhesive took place, and said stable band possessing an elastic elongation which, compared to a same stable band in which binding occurred in a tension-free state, is several times smaller.

2. A stable band composed of an untwisted arrangement of adhesively interconnected staple fibers and having an increased slope of the force-elongation curve in the force-elongation diagram, said stable band being stabilized by the staple fibers compressed into a compact band and bonded by a set adhesive material remaining in the band following compression, said stable band comprising said compact band having been elongated in its wet state within the limits of elastic deformation by application of a tension force following compression of the staple fibers into said compact band and while binding of the adhesive took place, said stable band possessing a force-elongation curve in the force-elongation diagram wherein'the slope thereof, compared to a same stable band in which binding occurred in a tension-free state, is increased, and said stable band being capable of being drafted.

References Cited UNITED STATES PATENTS 2,454,830 11/1948 Newton 161176 2,461,094 2/1949 Taylor 156229 X 1,803,129 4/1931 Palmer 1l77 X 2,977,665 4/1961 McElrath 1177 X WILLIAM A. POWELL, Primary Examiner US. Cl. X,R. 616 2 494

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