IL31268A - Non-woven fibre structures and their manufacture - Google Patents

Description

Non-woven fibre structures and their manufacture GLANZSTOFF A.G.

Ct29516 This invention relates to non-woven fibre structures, which can be used for filling cushions, pillows and quilted articles, and to their manufacture.

Cushions, pillows and quilted articles, such as quilts or anoraks, have been filled with non-woven bonded fibre structures consisting of staple fibres,, and also with non-woven fibre structures which consist of continuous filaments. Such non-woven fibre structures are preferably manufactured by spinning continuous filaments of synthetic polymers from multi-aperture nozzles so that the filaments, if necessary after drawing, are accumulated on suitable support means. Usually turbulence texturing is carried , out either by subjecting the filaments to blowing or by, applying an electrical field before collecting the filaments.

She present invention provides non-woven fibre structures for use for filling cushions, pillows, pads, quilted articles or the like, which structures comprise layers, laps or webs made from continuous preferably hollow or tubular, synthetic-polymer filaments, in which structures the cavity volume amounts to 10-30$ and the crimping arc number of the individual filaments is 50 to 150 arcs per cm. , of filament length.

For very bulky and voluminous structures, e.g. for filling elements for quilted articles, the use of hollow polyester filaments, and especially of polyethylene terephthalate is preferred, the crimping arc number is preferably 65 to 100 arcs; and the cavity volume is preferably 12 to 2 $.

The invention also provides a process for the manufacture of the aforesaid non-woven fibre structures, in polymer filaments and having a permanent crimp and an individual filament count of 0.5 to 20 den, and a crimping arc number of 50 to 150 per 10 cm., are subjected to a temporary elongation sufficien to bring the individual filaments within the range of their elastic strain under a load of at leas 0*1 pound/denier; the tension in the tow is then released su iciently to reform the crimped structure of the Individual lame s and to permit the tow to spread out laterally; and the crimped structure is taken off or deposited without tension. , The term "range of elastic strain" means that region of the stress-strain curve which extends up to a specific load value of the individual crimped filaments, which load value is that at which an identical bu uncrimped tow exhibits a permanent extension belo 4$. The optimum loading and Tilth it the degree of elongation, varies for different types of polymer filaments, but can be readily determined by a few preliminary tests. The optimum effect is achieved when the crimped tow, after a temporary elongation, spreads apart to form an unwoven fibrous web or fleece structure of maximum width. The maximum specific loading may be considered to be the load value at which the crimp of the tow, after removal of load, still just reforms along the tow.

However, it is generally advisable to keep the load below thi maximum loading value.

With polyethylene terephthalate filaments, the temporary elongation is carried out ¾ith the aid of such a load that the permanent elongation produced in the tow is less than t and preferably less than 1.5 . However, the load must also be at least 0.1 pound/den. (p/den) With tubular polyethylene terephthalate filaments . which have an individual filament count of 0.5 to 20 den,, preferably 3 to 8 den. and a oriraping arc number of 60 to 150, preferably 80 to 150, per 10 cm., a load of 0.1 to 1 p/den, has been found satisfactory. However,with a load of 0.5 to 0.8 p/den. extremely good results can be obtained.

The invention is not limited to the starting materials indicated above. If the non-woven fibre structures are to be further processed to produce lining or wadding fabrics or non-woven textile webs where the bulk is less important, then multifilament tows made from polyamides, polypropylene or other synthetic polymers may be used. The chemical constitution of the polymers used, and any pretreatments to which the filamerxts have been subjeoted during manufacture,- have an effect on the final product. This applies, for example, to the spinning conditions and to the nature and degree of the drawing and crimping to which the filaments have been subjected. These factors must be Considered when the process conditions are related and certain desired properties are to be produced in the final product.

An important consideration in the performance of this invention is the degree of crimping, i.e. the number of crimping arcs per unit of filament length. It does not matter what kind of crimping is used or how the crimping has been obtained. For example stuffer-box-crimped multifilament tows which have a two-dimensional crimp may be used, but the invention may also be applie very successfully to filaments which have a three-dimensional crimp.. Such filaments or tows are produced, for example, by spinning two chemically or physically different polymers with the The individual filament count may vary within relatively wide limits and must "be chosen to suit the intended application. Likewise the particular yarn used depends on the Intended application. Very good results are obtained with yarns which have an individual filament count of 3 to 8 den.

The spreading-out effect is most obviously affected by the degree of elongation which, according to the invention, mus take place in the range of elastic strain under a load of at least 0.1 p/den. At the lower and upper limits of that range of strain or the amount of loading the spreading-apart is usually only slight but a temporary elongation within such limits is still reasonably within the scope of the invention.

When the loading force acts on crimped multifilament tow the crimp first "disappears" by becoming latent, and the tow appears to b almost smooth before the filaments are elongated. It is desirable that before the device which elongates the tow within the range of elastic strain, an apparatus is arranged in which the elongation ean take place predominantly within the zone of crimping elongation, i.e. the crimp simply "straightens out". For example, conventional braking devices are suitable for this purpose.

The width of the unwoven web according to the invention, which is produced by this process, depends, of course, on the number of Individual filaments ©f the tow used. This number may be, for example, between 3,000 and 30,000 or more, depending on the purpose for which the product is intended.

The process according to the invention is not limited to the use of specific apparatus, but devices in which the elongation of the tow is effected between triple or quadruple roller arrangements have been found to be particularly suitable. The devices must allow for the accurate adjustment and maintenance of the low degrees of tension which are necessary. After the drawing step, the tension in the tow may be released, and the tow may be taken off in a tensionless condition. However, as a rule it is more convenient to guide the tow, after the second roller unit, over a second take-off device behind which a traversing device is arranged.

The handling of the tow between the second roller unit and the take-off device may be varied within wide limits. Thus, for example, it is possible to release the tension in the tow, completely or partially, so that the elastic elongation and, where appropriate, the crimp, is or are able to reform entirely or partially. In this case, a spreading-out effect is produced in the tow in this zone, the extent depending on the lessening of the tension. The elongation of the tow according to the invention may, however, be effected in two stages, in which case - if the peripheral velocities of the roller units are, in sequence, v^, 2 and v^ - the condition ^ The invention is described below, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic representation of an apparatus 31268 2 Pig. 2 is a diagrammatic perspective view of a non-^woven fibre structure according t© the invention in the form of a colled lap; Pig. 3 shows similarly a fibre structure in the form cross-laid superposed layer®.

In the example here contemplated, polyethylene terephthalate is spun from a solution viscosity 1*60 (measured in a Vf» solution in m-cresol at 25°C.) with the aid of a 180-aperture nozzle, whereby a tubular^filament tow is produced. This tow is drawn, in a conventional manner, in an atmosphere of steam at 160°C. (drawing ratio 1:4*1) and is subsequently crimped in a stuffer box. The tow then has the following properties: Strength 48 Rkm' (29.3 g/den.) Elongation 45 Cavity volume approximately 12# Individual count 5·5· den.

Crimping arc number 100 per 10 cm.

She crimping arc number is counted out On filament lengths which have been loaded with 3 mg.» a crimp or arc being considered to be any marked change in direction. Thus, a filament following a 360° sinus curve represents two arcs.

This tow is fed from a supply container 1, over a torsion bar braking arrangements 2 and deflecting rods 3» ». to a set of three rollers 6. Arranged before the latter is a tow guide 5» The peripheral velocity of the three rollers $ is 60 m/¾in. The tow is elongated by about 8 to 1Q# between the tension corresponding to a loading of 0.75 p/den. After leaving the rollers 7 the tow is guided over two rods 8 to a pair of takeoff rollers 9 whose peripheral velocity corresponds to that of the rollers 7. Behind the rollers 9 the tow is spread out to form an unwoven fibrous structure having a width of approximate* ly 55 em. and is deposited, by means of a simple traversing device* in a eardboard box 10.

Instead of the receiving container shown in Figure 1, any other suitable device may be used. %us, for example, for the manufacture of cushions or pillows or pads, the non-woven fibre web is wound loosely on a reel either from the receiving container 1, or directly after leaving the takeoff rollers 9. The coiled lap thereby formed is shown in Figure 2.

The non-woven wsb may instead be deposited in a number of layers one above the other.

The filling elements for cushions or the like manufactured in either way are very soft and bulky and much more stable in shape than are conventional fillings consisting of fibres. With both the lap-shaped and the layered structures -it is possible, by Inwardly folding the end portions of the web, to prevent any of the filament ends from being disposed on the surface of the filling so that tho danger that iey may project through the cover of the cushion or the like. However, even without such measures the aforesaid danger is much smaller than with conventional filling elements consisting of fibres.

For the manufacture of quilted articles, thicker or thinner unwoven fibre structures may be used, depending On the desired result. For quilts or sleeping bags, for example, a 31268/2 - ( whereas, for garments, thinner non-woven fibre structures are generally preferred. In layered structures the filaments ¾y extend substantially in one direction, or they may form any desired angles with each other by cross-laying. Figure 3 shows a sector of a quilted article filling which has been formed by crosslaying.

Claims (12)

31268/2 10

1. Non-woven fibre s ructures for use for filling cushions, pillows, pads, quilted articles or the like, which structures comprise layers, laps or webs made from continuous, preferably hollow or tubular, synthetic-polymer filaments, in which structures the cavity volume amounts to 10-30$ and the crimping arc number of the individual filaments is 50 to 1?0-arcs oer 10 cm.* of filament length.

2. A structure as claimed in Claim 1 in which the crimp of the filaments is between 65 and 100 arcs per 10 cm.

3. A structure as claimed in Claim 1 or 2, in which the filaments used are of polyethylene terephthalate.

4. A structure as claimed in any of Claims 1 to 3, in which the filaments are duffer-box-erimped endless tubular polyester filaments.

5. A structure as claimed in any of Claims 1 to 4, having the form of a coiled lap.

6. A structure as claimed in any of Claims 1 to 4, comprising superposed layers, e.g. in c ross-layered disposition.

7. A process for the manufacture non-woven fibre structure according to any of Claims 1 to 6, in which drawn multifilament tows made from continuous filaments of synthetic polymers and having a permanent crimp and an individual filament count of 0.5 to 20 den., and a crimping arc number of ϋθ to 150 per 10 cm., are subjected to a temporary elongation sufficient to bring / the individual filaments within the range of their elastic st/ under a load of at least 0.1 pound/denier? the tension in tty 31268/2 ' - 11 - is then released sufficiently to reform the crimped structure of the individual filaments and to permit the tow to spread out laterally; and the crimped structure is taken off or deposited without tension.

8. A process as olaimed in Claim 7, in which the filament count of the tow is between 3 and 8 denier.

9. » Λ process as claimed in Claims 7 or 8, in which the crimping arc number of the yarn is between 80 and ,150 per 10 cm.

10. Λ process as claimed in any of. Claims 7 to 9» in which the tows used are made from polyethylene terephthalat© filaments.

11. A process as daimed in any of Claims 7 to 10, in which tows made from tubular filaments having a cavity volume of 10 to 0 , preferably 12 to 259*» are used,

12. A process as claimed in any of Claims 7 to 11, in which tows made from tubular filaments of polyethylene terephthalate are subjected to a temporary elongation under a load between 0.1 and 1 p/den., preferably between 0.5 and 0.8 p/den, For tie Applicants DR.REINHOLD COHN AND PARTNERS By: RC;BH