GB2265913A

GB2265913A - Warp knitted fabric

Info

Publication number: GB2265913A
Application number: GB9207888A
Authority: GB
Inventors: Nigel Whatmough
Original assignee: Courtaulds Textiles Holdings Ltd
Current assignee: Courtaulds Textiles Holdings Ltd
Priority date: 1992-04-10
Filing date: 1992-04-10
Publication date: 1993-10-13
Also published as: GB9207888D0

Abstract

A warp knitted satin fabric includes a back group of elastomeric yarns (10) knitted to form separate wales of pillar stitches and a front group of non-elastomeric yarns (12) each of which is knitted in with a pair of said wales of pillar stitches, the pair being spaced apart by at least one intermediate wale to form floats of non-elastomeric yarn on the front surface of the fabric which extend over said at least one intermediate wale. The non-elastomeric yarn may be a lustre, eg trilobal, yarn. It may float across one, two or three wales. The fabric may be heat-set. <IMAGE>

Description

The present invention relates to a warp knitted elasticated satin fabric and a method of producing a warp knitted elasticated satin fabric.

Warp knitted satin fabrics are known, they generally comprise fabric knitted on a Tricot or Raschel machine using two fully threaded guide bars; a typical lapping motion being the front bar undergoing a lapping motion of 1-0,3-4 and the back bar undergoing a lapping motion of 12,1-0.

The yarn threaded on the front guide bar creates floats on the surface of the fabric and use of a suitable yarn such as a trilobal yarn creates a lustre effect on the front surface of the fabric.

It is desirable to produce elasticated satin fabric for example for use in lingerie and fashion wear.

Heretofore it has been known to provide elastication of a warp knitted satin fabric of the type described above by replacing the back bar yarn with an elastane yarn, normally on a Tricot machine, although the same construction could be made on a Raschel machine.

It is also common practice to produce on Raschel machines an elasticated satin by laying in an elastane yarn from a third guide bar in a construction as described above. It is also known to produce variants of this construction, and also a two-bar construction incorporating a laid-in elastane yarn on Raschel machines.

The knitted-in elastane yarn produces a strong widthwise contraction of the fabrics as it emerges from the knitting machine. In the case of the Raschel construction, with a laid-in elastane yarn there is also a widthwise contraction although this is not as severe as with the knitted-in elastane construction.

In either case, this contraction tends to cause the surface floats created by the front bar yarns to rise.

This encourages snagging of the surface floats which is undesirable as it detracts from the appearance of the fabric. Furthermore, since the floats do not lay flat there tends to be a reduction in the lustre of the front surface of the fabric. Furthermore, in the case of the laid-in constructions the elastomeric yarn is not effectively anchored within the fabric so that on cutting, run-back of the elastomeric yarn is possible.

According to one aspect of the present invention there is provided a warp knitted satin fabric including a back group of elastomeric yarns knitted to form separate wales of pillar stitches and a front group of non-elastomeric yarns each of which is knitted in with a pair of said wales of pillar stitches, the pair being spaced apart by at least one intermediate wale to form floats of non-elastomeric yarn on the front surface of the fabric which extend over said at least one intermediate wale.

Said wales may be formed by open or close lap pillar stitches. Preferably the pillar stitches are open lapped and the lapping motion for the back bar is preferably 0 1,1-0.

The elastomeric yarn is preferably an elastane yarn

such as Lycrat The elastomeric yarn preferably has a yarn count in the range 22 to 78 decitex. Preferably the

elastomeric yarn is a flat LycraLyarn of about 44 decitex.

t Preferably the floats of the non-elastomeric yarns extend over between 1 to 3 adjacent intermediate wales of pillar stitches. The lapping motion of the front bar is preferably chosen to be 2-3,1-0; 3-4,1-0; or 4-5,1-0 and so produce closed laps.

Preferably the motion of the front and back bars are in phase; i.e. they move in the same direction at the same time.

The non-elastomeric yarn is preferably a yarn exhibiting good lustre characteristics such as a trilobal multi filament yarn. The non-elastomeric yarn may be a polyamide or a polyester. The yarn count of the nonelastomeric yarn is preferably between 16 to 78 decitex.

Preferably the non-elastomeric yarn has a count of about 44 decitex.

According to another aspect of the present invention there is provided a process for producing an elasticated warp knitted satin fabric, the process including threading a back bar of a warp knitting machine with a group of elastomeric yarns for knitting at each needle position, threading a front bar of the knitting machine with a group of non-elastomeric yarns for knitting at each needle position and operating the back bar so as to produce separate wales of pillar stitches and operating the front bar so as to knit each non-elastomeric yarn in with a pair of said wales which are spaced apart by at least one intermediate wale so as to produce on the front surface of the fabric floats of non-elastomeric yarn extending over at least one of said wales.

Preferably the lapping motion for the back bar is O- 1,1-0 and the lapping motion for the front bar is either 23,1-0; 3-4,1-0; or 4-5,1-0.

Preferably the fabric is knitted on a tricot knitting machine.

Knitting of the group of elastomeric yarns so as to produce separate wales of pillar stitches provides the fabric with lengthwise stretch with reduced widthwise stretch. Accordingly, the width of the fabric emerging from the knitting machine does not reduce appreciably. For example, a fabric knitted according to the present invention knitted on a tricot machine at a width of about 4 metres, when emerging from the machine can produce two widths of fabric of about 190cm each; whereas a conventional elasticated fabric having laid-in elastomeric yarn knitted on a Raschel machine at a width of 3 metres reduces to a single width of about 2 metres on emerging from the machine.

In addition, since the fabric of the present invention does not contract in the width wise direction by an appreciable amount on leaving the knitting machine, the floats of non-elastomeric yarn are not encouraged to rise and so remain flat with the surface of the fabric. This provides the beneficial effect of producing a high lustre appearance and also reduces the likelihood of snagging.

In addition, in the fabric of the present invention the problem associated with run-back of the elastomeric yarn is substantially reduced. This arises due to the fact that the elastomeric yarn is not only knitted in with stitches formed by the non-elastomeric yarn but that during the subsequent heat setting treatment of the fabric, those zones of the elastomeric yarn which touch with one another within the stitch loop tend to bond together and thereby provide a positive lock. The heat treatment process is therefore preferably performed so as to encourage such bonding of said zones.

In view of the simple construction of the elasticated fabric according to the present invention it is possible to knit the elasticated fabric on a two-bar tricot knitting machine without modification and yet produce an elasticated warp knitted satin of superior satin finish to satin previously knitted on a tricot knitting machine.

EXAMPLE Reference is now made to the accompanying drawing which is a lapping motion diagram showing the lapping motions of the back bar and front bar of a warp knitting machine, preferably a tricot knitting machine.

The back bar is fully threaded with a group of elastomeric yarns, preferably an elastane such as Lycra (RTM) having a yarn count of about 44 decitex, for example 44 decitex T239B Lycra.

The machine is programmed so that the back bar undergoes the lapping motion 0-1,1-0 repeat. This is illustrated in the diagram by reference to a single yarn 10 from the group of elastomeric yarns. As can be seen from the diagram the lapping motion knits each yarn into a separate wale of open lap pillar stitches The front bar is fully threaded with a group of nonelastomeric yarns, preferably a polyamide or a polyester.

The non-elastomeric yarn preferably has a yarn count of about 44 decitex and may be a mono or multi filament yarn, for example 44 decitex 12 filaments bright trilobal.

The machine is programmed so that the front bar undergoes the lapping motion 2-3,1-0 repeat. This is illustrated in the diagram by reference to a single yarn 12 from the group of non-elastomeric yarns.

The lapping motion of the front bar creates closed laps and produces floats F which extend across a vertical row of dots 15 representative of a wale of pillar stitches.

Thus in the knitted fabric the lapping motion 2-3,1-0 repeat produces floats F extending across one wale. A lapping motion 3-4,1-0 repeat would produce floats F extending across two wales and a lapping motion 4-5,1-0 would produce floats F extending across three wales.

Preferably the motions of the front and back bar are in phase, i.e. they move in the same direction at the same time.

However, it will be appreciated that the motions of the front and back bar may be performed out of phase i.e.

the front and back bars move in opposite directions at the same time.

The yarn count for the elastomeric and non-elastomeric yarns in the above example are chosen to be the same.

However, it will be appreciated that the yarn counts for the elastomeric and non-elastomeric yarns may be different.

For example, decreasing the yarn count for the elastomeric yarns reduces the amount of elastication. It will also be appreciated that the non-elastomeric yarn is defined by decitex, filament count, lustre and polymer, the variation of which affect the finished product.

Claims

1. A warp knitted satin fabric including a back group of elastomeric yarns knitted to form separate wales of pillar stitches and a front group of nonelastomeric yarns each of which is knitted in with a pair of said wales of pillar stitches, the pair being spaced apart by at least one intermediate wale to form floats of non-elastomeric yarn on the front surface of the fabric which extend over said at least one intermediate wale.

2. A fabric according to claim 1 wherein the pillar stitches are opened or closed lapped.

3. A fabric according to claim 1 or 2 wherein the elastomeric yarn has a yarn count in the range 22 to 78 decitex.

4. A fabric according to claim 3 wherein the elastomeric yarn is a flat yarn of about 44 decitex.

5. A fabric according to any preceding claim wherein the elastomeric yarn is an elastane yarn.

6. A fabric according to any preceding claim wherein the floats of nonelastomeric yarns extend over between 1 to 3 adjacent intermediate wales of pillar stitches.

7. A fabric according to any preceding claim wherein the non-elastomeric yarn is a yarn exhibiting good lustre characteristics.

8. A fabric according to claim 7 wherein the non-elastomeric yarn is a trilobal multi-filament yarn.

9. A fabric according to any preceding claim wherein the non-elastomeric yarn has a yarn count between 16 to 78 decitex.

10. A fabric according to claim 9 wherein the yarn count of the nonelastomeric yarn is about 44 decitex.

11. A fabric according to any preceding claim wherein the non-elastomeric yarn is a polyamide or polyester yarn.

12. A warp knitted satin fabric substantially as herein described with reference to and as illustrated in the accompanying drawings.

13. A process for producing an elasticated warp knitted satin fabric, the process including threading a back bar of a warp knitting machine with a group of elastomeric yarns for knitting at each needle position, threading a front bar of the knitting machine with a group of non-elastomeric yarns for knitting at each needle position and operating the back bar so as to produce separate wales of pillar stitches and operating the front bar so as to knit each non-elastomeric yarn in with a pair of said wales which are spaced apart by at least one intermediate wale so as to produce on the front surface of the fabric floats of non-elastomeric yarn extending over at least one of said wales.

14. a process according to claim 13 wherein the lapping motion for the front bar is either 2-3,1-0; or 3-4,1-0; or 4-5,1-0.

15. a process according to claim 14 wherein the lapping motion for the back bar is 0-1,1-0.

16. A process according to claim 15 wherein the lapping motions of the front and back bars are in phase.

17. A process according to any of claims 13 to 16 wherein the fabric is knit on a tricot knitting machine.

18. A process according to any of claims 13 to 17 wherein the fabric is heat set.

19. A process for producing a warp knitted satin fabric substantially as herein described with reference to and as illustrated in the accompanying drawing.