GB2201976A

GB2201976A - Woven elasticated material

Info

Publication number: GB2201976A
Application number: GB08805199A
Authority: GB
Inventors: Arthur Dagg; Michael Rafter
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-03-06
Filing date: 1988-03-04
Publication date: 1988-09-14
Anticipated expiration: 2008-03-04
Also published as: GB8805199D0; IE870572L; IE60113B1; LU86936A1; GB2201976B

Abstract

Woven material for waistbands are elasticated by inclusion of elastane in the weave, characterised in that bare elastane is used, and the slippiness of the bare surface of the elastane is counteracted by the use of a weaving pattern such that the elastane interlocks with the wefts of the woven material, thereby preventing or reducing slip back. Alternatively a flexible bonding agent may be added to lodge in the interstices and prevent slip back either by application to the warps or, after weaving, to the finished fabric. An aqueous solution of surfactants and polymeric material may be mixed with polyvinyl acetate resin (10 grams/litre), water and softener.

Description

WOVEN ELASTICATED MATERIAL The present invention relates to woven material which is elasticated so as to be useful in the manufacture of garments. One example of such material is a strip of woven polyester yarn which is elasticated so as to be useful in making waistbands in shorts, trunks or undergarments.

In the past elastication has been achieved by inclusion of rubber warps during the weaving process.

These warps may be covered or uncovered.

Rubber as an elastication material suffers from certain disadvantages. One disadvantage is the high shrinkage of the fabric in which the rubber is used. A second disadvantage is that rubber degrades in the dry cleaning process.

To overcome these disadvantages strips of woven fabric have been manufactured in which the elastication material consists of elastane instead of rubber. The elastane used has been that sold under the trade mark "LYCRA" by the Du Pont Company of Delaware, United States of America. Elastane does not suffer from shrinkage or degradation, or at least not to the same extent as rubber.

Elastane however has a disadvantage of its own, namely that it is very slippy. Thus in changing from the use of rubber to the use of elastane it was not simply a question of substituting elastane for rubber. This would have presented difficulties in both the manufacture of the woven fabric strip and in the finished garment.

The difficulty during manufacture would have been that elastane could not be fed to the weaving loom in the same way as rubber. This is because commercially available elastane comes in the form of knitted tape, which unknits unevenly into individual strands. This may be compared with rubber which comes in the form of tapes of loosely bonded parallel lengths which easily break apart. If elastane which unknits unevenly were fed to the weaving loom in the same way as was done with rubber, the result would be the inclusion in the woven fabric of elastane warps under different tensions, leading to crimping and puckering of the finished material.

The difficulty in the finished garment would have been that if the waistband were extended, the elastane would initially extend with the woven fabric waistband but would then slip back through the fabric weave while the latter remained extended. Rubber, too, suffers from slip back, but to a much lesser degree, which has been found acceptable if undesirable.

The problem of the slippy surface of elastane was overcome by covering the elastane with an outer covering having a less slippy texture, and this method of using elastane has been in use for some years now. As previously mentioned, it had already been known to cover rubber.

Covering the elastane, while overcoming the above mentioned difficulties in manufacturing and in the finished garment, presents other disadvantages. Firstly, the covering process is a relatively specialized and expensive process. Secondly, the elastane when covered is of relatively large cross section. The large cross section means that the strip of material is thicker, producing a waistband which may be undesirably bulky, particularly at those points where a double thickness arises, for example where the two ends of a waistband overlap, or where the strip is bent back on itself. The large cross section also means that the strip is easier to damage. There are two reasons for this.Firstly, warps of larger diameter are more likely to become damaged during sewing, because a needle inserted through the strip is likely to penetrate the warp instead of being deflected between warps as would happen with warps of lesser diameter. Secondly, damage to an individual warp is more serious because there are relatively fewer warps per unit width of strip.

The object of the present invention is to provide an improved elasticated material.

In one aspect the invention provides woven material which is elasticated by inclusion of elastane in the weave, in which the elastane which is used is bare instead of covered, but the slippiness of the surface of the elastane is counteracted by the use of a weaving pattern such that the elastane interlocks with the wefts of the woven material, thereby preventing or reducing slip back.

In another aspect the invention provides woven material which is elasticated by inclusion in the weave of an elastication material, which may be rubber or elastane or another material, and further including a flexible bonding agent which lodges in the interstices or junctions between the woven material and the elastication material, thereby preventing or reducing slip back.

The flexible bonding agent may be added either before or after weaving. Adding the flexible bonding agent before weaving may be done at the stage where the warps under tension are just about to enter the heddles of the loom. Because the warps are at this stage separated and under tension an efficient application is effected.

Adding the flexible bonding agent after weaving may conveniently be done during a pre-shrinking stage which takes place before the woven material is used, by adding the bonding agent in liquid form to the wetting agent used in the pre-shrinking stage.

In another aspect, the invention provides woven material which is elasticated by means of both the foregoing features in combination, namely inclusion of bare elastane in a weaving pattern such that the elastane interlocks with the wefts of the woven material, and inclusion of a flexible bonding agent which lodges in the interstices or junctions between the woven material and the elastane.

According to a further aspect of the invention there is provided a method of weaving elastane which is supplied in knitted bare form, comprising unknitting the knitted bare elastane to give individual strands of bare elastane under varying tensions in a first stage, and then equalising the tensions of the different strands in a second stage before feeding to the weaving loom.

The invention also provides weaving apparatus comprising a weaving loom and a drive roller arrangement for tensioning equally the individual strands of material being fed to the loom, the apparatus being adapted to be used in the weaving of bare elastane supplied in knitted form by provision of a further drive roller arrangement drivable at a lower speed than the previously mentioned drive roller arrangement whereby knitted elastane may first be unknitted at the further drive roller arrangement and then fed in the form of individual strands to the previously mentioned drive roller arrangement.

The further drive roller arrangement may be connected to the first mentioned drive roller arrangement via reduction gears.

The invention will now be described more particularly by way of example with reference to the accompanying drawings. In the drawings: Figure 1 is a perspective view of part of a strip of woven elasticated material, indicating dimensions thereof, which material may be either of known type or according to the invention; Figures 2, 3 and 4 are various views of woven material which has been elasticated in known manner by inclusion of covered or bare rubber or covered elastane; Figures 5, 6 and 7 are views similar to Figures 2, 3 and 4, of woven material which has been elasticated according to the invention by inclusion of bare elastane; Figure 8 is a sectional elevation of apparatus for applying the flexible bonding agent; and Figure 9 is a side elevation of the drive roller arrangements in operation, with the elastane also shown in plan.

Referring to the drawings, Figure 1 shows part of a strip of woven material of width W. A part of the strip, of length "1" is considered in more detail in Figures 2 and 5.

Figure 2 is a so called "point paper diagram" illustrating length "1" of a strip of woven polyester elasticated in conventional manner using rubber. A light letter "X" represents a polyester warp overlying a polyester weft (the wefts are not shown) while a blank space between two light letters "X" represents the polyester warp underlying the weft. Thus the polyester warp and weft pattern may be seen. A dark letter "X" represents the elastication material, in this case rubber, which is included in the weave as warps. It will be seen that there are three polyester warps between adjacent rubber warps. An encircled letter "X" represents a plush facing to the woven material.

Figure 3 is another view of the strip of Figure 2, shown extended under tension. This view is a sectional side elevation of the strip showing a side view of a single rubber warp 20 and showing sectional views of the polyester wefts 21. The polyester warps have been omitted. It will be noted that the rubber warp 20, which is much stronger than the polyester, lies flat and that the polyester wefts 21 lie alternately above and below the rubber warp 20.

Figure 4 is a view similar to Figure 3, but with the strip no longer extended. As the tension is released, the rubber warp 20 expands in diameter, and in this way locks against the polyester weave.

Figure 5 is a point paper diagram, similar to Figure 2, but showing woven polyester elasticated using bare elastane, according to the invention. Some differences between this point paper diagram and that in Figure 2 will be immediately apparent. Firstly, there are considerably more polyester warps present, even though the width W of both strips and the number of warps of elastication material are the same. Thus there are six polyester warps between adjacent elastane warps. Secondly, the elastane warps are staggered relative to one another in that, as seen looking transversely across the strip, alternate warps of elastane overlie and underlie the wefts. The particular weaving pattern illustrated works very successfully, which was not expected.Instead it might have been expected that it would result in the wefts being cut by the elastane or would result in a material possessing insufficient elasticity due to the elastane being locked.

Figure 6 is another view of the strip according to the invention shown extended under tension. This view is a sectional side elevation of the strip (similar to Figure 3), and shows a side view of two adjacent elastane warps, 30a, 30b one behind the other and with the intervening polyester warps omitted from the drawing, and showing sectional views of the polyester wefts 31. It will be noted that the elastane warps 30a,30b undulate whereas the rubber warps lay flat.

Figure 7 is a view similar to Figure 6, but with the strip no longer extended. As the tension is released,. the elastane warps 30a,30b do not greatly increase in diameter as does the rubber warp. However, because of the weave pattern used, the elastane warps 30a, 30b and the polyester wefts 31 interlock with one another. Figure 7 may be compared with Figure 4. It will be appreciated that the weave structure used prevents the elastane slipping back.

Slip back may also be prevented by using a suitable flexible bonding agent, which lodges in the interstices or junctions between the elastane warps on the one hand and the polyester wefts and warps on the other hand. The flexible bonding agent may be included in or added to any woven material which includes an elasticating agent in the weave, so as to prevent or reduce slip back of the elasticating agent. The flexible bonding agent may be included in or added to woven material which has been elasticated in accordance with the invention, that is by including bare elastane in a weaving pattern such that the wefts and the elastane interlock, in which case the effect of the bonding agent is to supplement the resistance to slip back which is already provided for by the interlocking.The bonding agent may also be included in or added to woven material which has been elasticated in known manner by including rubber as an elasticating agent, in which case the effect of the bonding agent is to reduce or eliminate the small but undesirable amount of slip back present. The flexible bonding agent may also be used in other woven elasticated materials.

The flexible bonding agent may comprise an aqueous solution of a mixture of surfactants and polymeric materials.

Referring to Figure 8, the flexible bonding agent may be applied before weaving. In Figure 8 there is shown a lick roller arrangement 35 which is mounted on the weaving loom (not shown) between the stop motions and the heddles.

The direction of travel of the warps and the direction of rotation of the roller 36 are indicated by arrows. Adding the flexible bonding agent at this stage, when the warps are separated and under tension, results in a very efficient application of the bonding agent to the surface of each individual warp. The roller 36 is driven from weaving loom by means of a drive transmission (not shown) comprising a belt the tension of which may be adjusted to vary the speed of the roller 36. The speed at which the roller 36 is driven is much lower than the speed of travel of the warps. The lick roller arrangement 35 includes an adjustable scraper 37 for ensuring that only a thin film of flexible bonding agent is present on the roller 36.

The lick roller arrangement 35 also applies a lubricant to assist weaving. The lubricant is an emulsion of finely dispersed paraffin wax. The flexible bonding agent and lubricant are mixed in proportions of eight to one in an aqueous solution.

The flexible bonding agent may instead be added after weaving. In this case it is added as part of a single treatment stage in which the woven fabric is immersed in a bath containing a liquid mixture of the flexible bonding agent together with (a) polyvinyl acetate resin in a concentration of 10 grams per litre as a starching or stiffening agent, (b) resin to stabilize the polyester yarn, (c) water to preshrink the fabric, and (c) a softener to soften the face of the fabric, after which the woven fabric is dried.

Figure 9 is a side view of the apparatus used to feed bare elastane to a weaving loom. Bare elastane is commercially available in the form of knitted tape 40.

When a knitted tape 40 is pulled from one end it unknits into individual strands 41. As may be seen from the plan view of the end of the tape 40, the tape does not unknit uniformly across its width, and accordingly the individual strands 41 are under different tensions. The tape 40 passes through a first roller arrangement 42 comprising two driven rollers 42a,42b and an idler roller 42c, the effect of the roller arrangement being to tension the tape 40 so as to cause it to unravel at or just after leaving the first roller arrangement 42. The individual strands 41 then pass through a second roller arrangement 43 similar to the first but driven at a much greater speed, the effect of which is to uniformly tension the individual strands 41. The individual strands 41 under uniform tension then pass to the loom which is not shown.

The second roller arrangement 43 is driven from the loom in known manner. The first roller arrangement 42, which is the novel feature of the apparatus, is driven from the second roller arrangement 43 by a drive transmission which includes reduction gearing (not shown).

The ratio of the speeds of the second and first roller arrangements is 9.125:1.

Claims

1. Woven material which is elasticated by inclusion of elastane in the weave, in which the elastane which is used is bare instead of covered, but the slippiness of the surface of the elastane is counteracted by the use of a weaving pattern such that the elastane interlocks with the wefts of the woven material, thereby preventing or reducing slip back.

2. Woven material according to Claim 1, in which each polyester weft passes alternately over and under a successive elastane warp

3. Woven material according to Claim 1 or Claim 2, in which the ratio of polyester warps to elastane warps is between 5:1 and 7:1.

4. Woven material which is elasticated by inclusion in the weave of an elastication material, which may be rubber or elastane or another material, and further including a flexible bonding agent which lodges in the interstices or junctions between the woven material and the elastication material, thereby preventing or reducing slip back.

5. Woven material which is elasticated in accordance with Claim 1, 2 or 3 and also in accordance with Claim 4.

6. A method of weaving elastane which is supplied in knitted bare form, comprising unknitting the knitted bare elastane to give individual strands of bare elastane under varying tensions in a first stage, and then equalising the tensions of the different strands in a second stage before feeding to the weaving loom

7. A weaving apparatus comprising a weaving loom and a drive roller arrangement for tensioning equally the individual strands of material being fed to the loom, the apparatus being adapted to be used in the weaving of bare elastane supplied in knitted form by provision of a further drive roller arrangement drivable at a lower speed than the previously mentioned drive roller arrangement whereby knitted elastane may first be unknitted at the further drive roller arrangement and then fed in the form of individual strands to the previously mentioned drive roller arrangement.

8. Woven material substantially as herein described with reference to and as shown in Figures 5, 6 and 7 of the accompanying drawings.