US3770538A

US3770538A - Method of producing a stable band consisting of adhesively bonded staple fibers of high lengthwise stability

Info

Publication number: US3770538A
Application number: US00019243A
Authority: US
Inventors: W Naegeli
Original assignee: Pavena AG
Current assignee: Pavena AG
Priority date: 1969-03-21
Filing date: 1970-03-13
Publication date: 1973-11-06
Anticipated expiration: 1990-11-06
Also published as: BE747576A; ES377853A1; BR7017652D0; ATA229470A; CH436169A4; FR2037237A1; NL7002668A; GB1311798A; CH515350A; DE2012056A1; FR2037237B1; AT329413B; CA926712A; US3837998A; AU1249870A

Abstract

A method of producing a stable band composed of adhesively interconnected staple fibers of high lengthwise stability which contemplates treating the staple fibers with an excess of liquid in which an adhesive is distributed, squeezing off the liquid surplus and compressing the fibers by applying pressure into a compact band in which the adhesive binds. According to an important aspect of the invention, the band through application of a tension force is subjected to an elongation within the limits of elastic deformation while binding of the adhesive takes place. The invention also concerns a stable band of 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.

Description

United States Patent 1 Naelgeli 1 Nov. 6, 1973 METHOD OF PRODUCING A STABLE BAND CONSISTING OF ADHESIVELY BONDED STAPLE FIBERS OF HIGH LENGTI-IWISE STABILITY [75] Inventor: Werner Naege1i,Winterthur,

Switzerland [73] Assignee: Pavena AG, Basel, Switzerland [22] Filed: Mar; 13, 1970 [21] Appl. N0.: 19,243

[30] Foreign Application Priority Data Mar. 21, 1969 Switzerland 4361/69 [52] US. Cl. 156/85, 156/161 [51] lint. Cl B32b 31/20, 1329c 27/26 [58] Field of Search 156/161, 85, 196, 156/312 [56] 7 References Cited UNITED STATES PATENTS 3,438,844 4/1969 Kumin 156/161 FOREIGN PATENTS OR APPLICATIONS 898,518 6/1962 Great Britain 156/161 9/1959 Canada 156/161 2/1948 Canada 156/161 [57] ABSTRACT A method of producing a stable band composed of adhesively interconnected staple fibers of high lengthwise stability which contemplates treating the staple fibers with an excess of liquid in which an adhesive is distributed, squeezing off the liquid surplus and compressing the fibers by applying pressure into a compact band in which the adhesive binds. According to an important aspect of the invention, the band through application of a tension force is subjected to an elongation within the limits of elastic deformation while binding of the adhesive takes place.

The invention also concerns a stable band of 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.

24 Claims, 10 Drawing Figures PATENTEDNHY' 6am 3770.538 SHEEI 20F 2 a Fig. 10

INVENTOR. WERNER A/AEGEL METHOD OF PRODUCING A STABLE BAND CONSISTING OF ADHESIVELY BONDED STAPLE FIBERS OF HIGH LENGTHWISE STABILITY BACKGROUND OF THE INVENTION The present invention concerns a new and improved method of producing a staple band consisting of adhesively interconnected staple fibers and possessing high lengthwise or longitudinal stability, and further pertains to an improved stable band produced according to the aforesaid inventive method.

From French Pat. No. 1,433,424 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 by means of drying and transformed into a stable band possessing sufficient lengthwise stabilization for undergoing a drafting operation. It is further known from the aforementioned French patent that 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 sufficiently lengthwise stablized 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.

SUMMARY 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 forceelongation 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.

' 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 ob- I jects of the invention, which will become more readily apparent as the description proceeds, the inventive method 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 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 suffering permanent deformation. Such bands now can be 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 tension before binding takes place and its length may be maintained constant while binding occurs, in which case the elongation is subjected 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 causeband breakage.

The invention method can be carried out in a discontinuous process as well as in a continuous process. In discontinuous processing certain lengths of condensed, wet hands 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 adhesives used.

More explicitly, the discontinuous processing technique is described with reference to the following Examples'l to Ill 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) KS. origin, of 1 1/16 inch 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. No. 426,704 and is removed in the form of a compressed or compacted band. As treatment liquid there is used 7 percent aqueous solution of the commercially available starch derivative product NORE- DUX 100," marketed by the Swiss firm, Blattmann & Co., of Wadenswil, Switzerland. For checking a wet band of 1 meter length is cut from the hand delivered by the liquid applicator device and is freely laid out horizontally. Drying of the comparative band 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 Instron 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 elongated by 0.5 percent in its wet state, which corresponds to an elastic deformation of the wet band of 5 mm, and was clamped, a free length of 1 meter being maintained. Subsequently, again the band elongated and maintained at constant length is again dried during 3 minutes at a temperature of 80 C. The force-elongation diagram as shown by curve b was recorded. lnthe 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:

Curve Percent elongation Percent elongation applied in the wet of the stable band state (after binding) under load force a 0 1.95 b 0.5 1.0 e 1 0.8

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 A viscose staple of 40 mm cutting length and 1.3 den fiber fineness suitably prepared, in a band weight of 1972 tex is fed into a liquid applicator device already mentioned above and is taken off as a compressed band. As treatment liquid there is used a 2 percent solution of a carob seed derivative powder POLY- PRINT, marketed by the Swiss firm, Polygal Co, Meerstetten, Switzerland. A 1 meter length of band was dryed without tension at C and its force-elongation curve a shown in FIG. 2 was recorded on the lnstron 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 percent and was dryed at 80 C during 3 minutes. The resulting forceelongation diagram is shown in curve b. Similarly, a 1 meter length of the same band was elongated by 4 percent, clamped and dryed, curve c 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:

Curve Percent elongation Percent elongation of applied in the wet the stable band state (after binding) under load force B=IO kg a 0 3.0 b 2 0.85 c 4 0.65

Comparison of the elongation percentages of the bands in the diagram at a certain load force shows the elongation of the bands dried under tension to be about four times smaller. The result again is a band of approximately rigid behavior in the drafting zone.

The method is particularly well suited for processing highly crimped fibers, the lengthwise stabilization of which can be increased to several times the initial amount as illustrated by the following Example.

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 percent aqueous solution of the polyacrylate BAS-TX of the well known firm Badische Anilinund Soda-Fabriken, Ludwigshafen, Germany. Again, 3 band pieces each of 1 meter length were cut and dried at 80 C during 3 min with, i

one being laid out without tension,

the second being pre-elongated by 2 percent, and

the third being pro-elongated by 5 percent 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 B 10 kg., the following elongation percentages are found:

Curve Percent elongation Percent elongation of applied in the wet the stable band (after state binding) under load force B=l0 kg a 0 (tensionless) 12 b 2 3.5 c 5 2.25

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 fore andduring the binding phase by exposing the bands to a constant tensile load causing an elastic deformation in the set state. Such methods were applied in Examples IV to V1 described hereinafter.

EXAMPLE IV A band as described in Example I is treated with a 5.5 percent solution of the cellulose derivative Solvitose X0 and Solvitose XI (manufactured by Scholtens, Chemische Fabriken, Foxhal/Holland) mixed in the proportions one to four, 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 constant tension force 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 elongationpercentages under a load force of B =4 kg are given in the following table:

Load weight in grams applied in the wet state Curve a 10 b 150 c 300 Elongation of the dried band thus clearly tends to decrease as tensile stress during drying increases.

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 percent aqueous solution of VIBATEX S, a polyvinyl alcohol manufactured by CIBA Corp., Basel, Switzerland. The bands of 80 cm length again were loaded with weights of 10, 150, 300, 450 and 600 grams respectively and dried during 8 minutes at a temperature of 80 C. 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:

Percent elongation of the dried stable band under load force Weight load in grams applied in the wet state Curve 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 120 C. The force-elongation diagrams obtained from such bands are shown in FIG. 6. At a load force B 4 kg the elongation percentage summarized in the following table are found:

Curve Weight load in grams Percent elongation of applied in the wet the dried stable band state under load force a 10 2.25 b 150 1.4 c 300 0.96 d 450 0.78

From these resultsit is evident that using the same band tensions at a higher drying temperature, a reduction of elongation .can be achieved, which again results inimproved 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 0, 1, 1.5, 2 and 2.5 percent respectively, and in this state were clamped at both ends. The bands elongated and maintained at a constant length then were dried at 80 C. The corresponding elongation percegitages 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:

Curve Percent elongation Percent elongation of applied in the wet the dried stable band state under load force a 0 2.3 b 1 2.1 c 1.5 1.8 d 2 1.4 e 2.5 1.3

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

EXAMPLE VIII The same compressed bands of Terylene staple fiber as used in Example VII are elongated in the same manner as in Example VII and elongated by the same percentages and subsequently were dried. Drying temperature, however, was 120C instead of 80 C. The forceelongation curves, subsequently recorded on the Instron Tester, according to FIG. 8, show the elongation percentages at a load of B 4 kg summarized in the following table:

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 fibers mutually interconnected by the bound adhesive, now called stable band, leaves drum 4 and after passing through a traversing band guide 5 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 chosing 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 chosing a slightly tapered drum shape (drumshown 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 (drurn, shown in dash-dotted lines, D D,) so that the band fension 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'tension-free 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 chosing 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 can not redevelop.

As a further alternative a method of continuous processing can be chosen in which the compressed band 7 (FIG. 10) treated or impregnated with an adhesive distributed in a liquid is guided directly through a process ing 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 can not 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:

11. A method of producing a stable band composed of adhesively interconnected staple fibers and having an increased slope of the force-elongation curve in the force-elongation diagram, comprising the steps of providing an untwisted arrangement of staple fibers, treating the untwisted arrangement of staple fibers with an excess of liquid in which an adhesive is distributed, squeezing off the liquid surplus and compressing the untwisted arrangement of staple fibers by applying pressure into a compact band of mutually compressed staple fibers, binding the adhesive in the band, and subjecting the wet band to an elongation within the limits of elastic deformation after being compressed by applying a tension force thereto, at the latest while binding of the adhesive takes place for increasing the slope of the force-elongation curve of the stable band.

2. The method according to claim 1, further including the step of subjecting the wet band to an elongation within the limits of elastic deformation after being compressed and before binding of the adhesive occurs.

3. The method according to claim 1 further including the step of subjecting a wet throughpassing band, after being compressed and before binding of the adhesive takes place, to an elongation which is generated by the tension caused by a shrinkage of the band occurring during the binding of the adhesive.

4. The method according to claim 1, further including the step of subjecting a wet throughpassing band to an elongation within the limits of elastic deformation after being compressed and before binding of the adhesive occurs by imparting a higher speed to the throughpassing band before binding takes place than during the binding of the adhesive.

5. The method according to claim 1, wherein band the elongation during binding is effected by application of constant tension.

6. The method according to claim 1, wherein band the elongation during binding of the adhesive is effected by application of a constant clamping length to the band.

7. The method according to claim 1, wherein band the elongation during binding of the adhesive is effected by means of changing the clamping length of the band according to a predetermined function.

8. The method according to claim I, wherein band the band is subjected to an elongation of at least 1 per cent.

9. The method according to claim 1, wherein band the elongation is controlled to be larger than the shrinkage of the band occurring during binding.

10. The method according to claim 1, wherein binding is induced by drying at a temperature greater than room temperature.

11. The method according to claim 7, wherein band the during binding is subject to elongation by means of an increasing clamping length of the band.

12. The method according to claim 7, wherein band the during binding is subjected to elongated by means of a decreasing clamping length of the band.

13. A method of continuously producing a stable band of adhesively interconnected staple fibers and having an increased slope of the force-elongation curve in the force-elongation diagram, comprising the steps of:

a. providing a throughpassing untwisted arrangement of staple fibers;

b. treating the throughpassing untwisted arrangement of staple fibers with an excess of liquid in which an adhesive is distributed;

c. squeezing off the liquid surplus and compressing the untwisted arrangement of staple fibers by applying pressure into a compact band of mutually compressed staple fibers;

d. binding the adhesive in the band; and

e. subjecting the wet band to an elongation within the limits of elastic deformation after being compressed by applying a tension force thereto, at the latest while binding of the adhesive takes place in the band passing through a processing zone.

14. The method according to claim 13, further including the step of subjecting the wet throughpassing band to an elongation within the limits of elastic deformation after being compressed and before binding of the adhesive occurs by imparting a higher speed to the throughpassing band before binding takes place than during the binding of the adhesive.

15. The method according to claim 14, wherein the throughpassing band, before binding takes place, is subjected to an elongation which is generated by a tension caused by the shrinkage of the band occurring during the binding of the adhesive.

16. The method according to claim 13, wherein the throughpassing band during binding of the adhesive is subjected to an elongation by application of constant tension.

17. The method according to claim 13, wherein the throughpassing band during binding of the adhesive is subjected to an elongation by means of changing the tension according to a predetermined function.

18. The method according to claim 13, wherein the throughpassing band is subjected to an elongation of at least 0.5 percent.

19. The method according to claim 13, wherein the band is subjected to an elongation which corresponds to the amount of shrinkage of the band occurring during binding.

20. The method according to claim 13, wherein the throughpassing band is subjected to an elongation which is larger than the amount of shrinkage of the band occurring during binding.

21. The method according to claim 13, wherein binding is induced by drying at a temperature above room temperature.

22. The method according to claim 13, further including the steps of winding-up the stable band after binding of the adhesive, and imparting a winding speed to the stable band in relation to a delivery speed of the wet band such that there remains a tension in the band within the limits of elastic elongation.

23. The method according to claim 13 wherein the tension applied to the wet band increases above its initial value but below the elastic limit as the wet band progresses through the elongation zone.

24. The method according to claim 13 wherein the tension applied to the wet band reduces below its initial value but above zero as the wet band progresses

Claims

2. The method according to claim 1, further including the step of subjecting the wet band to an elongation within the limits of elastic deformation after being compressed and before binding of the adhesive occurs.
3. The method according to claim 1 further including the step of subjecting a wet throughpassing band, after being compressed and before binding of the adhesive takes place, to an elongation which is generated by the tension caused by a shrinkage of the band occurring during the binding of the adhesive.
4. The method according to claim 1, further including the step of subjecting a wet throughpassing band to an elongation within the limits of elastic deformation after being compressed and before binding of the adhesive occurs by imparting a higher speed to the throughpassing band before binding takes place than during the binding of the adhesive.
5. The method according to claim 1, wherein band the elongation during binding is effected by application of constant tension.
6. The method according to claim 1, wherein band the elongation during binding of the adhesive is effected by application of a constant clamping length to the band.
7. The method according to claim 1, wherein band the elongation during binding of the adhesive is effected by means of changing the clamping length of the band according to a predetermined function.
8. The method according to claim 1, wherein band the band is subjected to an elongation of at least 1 per cent.
9. The method according to claim 1, wherein band the elongation is controlled to be larger than the shrinkage of the band occurring during binding.
10. The method according to Claim 1, wherein binding is induced by drying at a temperature greater than room temperature.
11. The method according to claim 7, wherein band the during binding is subject to elongation by means of an increasing clamping length of the band.
12. The method according to claim 7, wherein band the during binding is subjected to elongated by means of a decreasing clamping length of the band.
13. A method of continuously producing a stable band of adhesively interconnected staple fibers and having an increased slope of the force-elongation curve in the force-elongation diagram, comprising the steps of: a. providing a throughpassing untwisted arrangement of staple fibers; b. treating the throughpassing untwisted arrangement of staple fibers with an excess of liquid in which an adhesive is distributed; c. squeezing off the liquid surplus and compressing the untwisted arrangement of staple fibers by applying pressure into a compact band of mutually compressed staple fibers; d. binding the adhesive in the band; and e. subjecting the wet band to an elongation within the limits of elastic deformation after being compressed by applying a tension force thereto, at the latest while binding of the adhesive takes place in the band passing through a processing zone.
14. The method according to claim 13, further including the step of subjecting the wet throughpassing band to an elongation within the limits of elastic deformation after being compressed and before binding of the adhesive occurs by imparting a higher speed to the throughpassing band before binding takes place than during the binding of the adhesive.
15. The method according to claim 14, wherein the throughpassing band, before binding takes place, is subjected to an elongation which is generated by a tension caused by the shrinkage of the band occurring during the binding of the adhesive.
16. The method according to claim 13, wherein the throughpassing band during binding of the adhesive is subjected to an elongation by application of constant tension.
17. The method according to claim 13, wherein the throughpassing band during binding of the adhesive is subjected to an elongation by means of changing the tension according to a predetermined function.
18. The method according to claim 13, wherein the throughpassing band is subjected to an elongation of at least 0.5 percent.
19. The method according to claim 13, wherein the band is subjected to an elongation which corresponds to the amount of shrinkage of the band occurring during binding.
20. The method according to claim 13, wherein the throughpassing band is subjected to an elongation which is larger than the amount of shrinkage of the band occurring during binding.
21. The method according to claim 13, wherein binding is induced by drying at a temperature above room temperature.
22. The method according to claim 13, further including the steps of winding-up the stable band after binding of the adhesive, and imparting a winding speed to the stable band in relation to a delivery speed of the wet band such that there remains a tension in the band within the limits of elastic elongation.
23. The method according to claim 13 wherein the tension applied to the wet band increases above its initial value but below the elastic limit as the wet band progresses through the elongation zone.
24. The method according to claim 13 wherein the tension applied to the wet band reduces below its initial value but above zero as the wet band progresses through the elongation zone.