GB2454677A

GB2454677A - An elasticized warp knitted fabric and a process for knitting hereof.

Info

Publication number: GB2454677A
Application number: GB0722296A
Authority: GB
Inventors: Andy Carey
Original assignee: Montfort Services Sdn Bhd
Current assignee: Montfort Services Sdn Bhd
Priority date: 2007-11-14
Filing date: 2007-11-14
Publication date: 2009-05-20
Anticipated expiration: 2027-11-14
Also published as: WO2009063203A1; EP2220275A1; GB0722296D0; GB2454677B

Abstract

An elasticized warp knitted fabric (50; 100) and a process for knitting hereof. The elasticized warp knitted fabric comprises a group (52) of front yarns (54) knitted to form separate wales (56) of pillar stitches (58). The wales (56) are interconnected by at least one group (60, 62) of elastomeric rear yarns (64, 66). The path of each elastomeric rear yarn (64, 66) between respective wales (56) determines the modulus of the fabric (50; 100) in a course wise direction. In a first preferred embodiment each elastomeric rear yarn is knitted within a given wale for seven courses and the elastomeric rear yarn extends between three or more adjacent wales in a first direction and in a second direction, the first and second directions being opposite one another and placed before and after the seven courses respectively.

Description

AN ELASTICIZED WARP KNITTED FABRIC AND A PROCESS FOR

KNITTING AN ELASTICIZED WARP KN1TIED FABRIC This invention relates to an elasticized warp knitted fabric and a process for knitting an elasticized warp knitted fabric.

Elasticized warp knitted fabrics have long been used for corsetry, foundation garments and swimwear. More recently these fabrics have been used in lingerie, and active sports and leisure wear.

Power net is a widely-known, conventional, elasticized warp knitted fabric.

Figure 1(a) shows the structure of a conventional power net fabric 10 which includes a ground 12 knitted from first and second non-elastomeric yarns 14, 16.

Typically thc non-elastomeric yarns 14, 16 are nylon.

First and second elastomeric yarns 18, 20 are laid into the knitted ground 12. The non-elastomeric yarns 14, 16 lock to respective elastomeric yarns 18, 20 via a closed lap 26 to secure the elastomeric yams 18, 20 to one another.

Figure 1(b) shows the corresponding lapping movements of front and rear bars 22, 24 of a warp knitting machine that are required to produce the aforementioned power net structure.

The modulus or, so called, "power", i.e. the extensibility and recovery of such a power net fabric 10 in a given direction, is determined by the extensibility and recovery of the elastomeric yarns 18,20 incorporated within the fabric 10 Only a limited number of elastomeric yams 18, 20 having differing extensibility and recovery characteristics are available. As a result, it is possible only coarsely to modify the modulus in a given direction of a conventional, power net fabric 10 since any modification is limited by the availability of elastomeric yams 18, 20 having different extensibility and recovery characteristics. Accordingly it is difficult to tailor precisely the modulus in a given direction of a conventional power net fabric 10 according to the requirements, for example, of a particular garment.

s Therefore there is a need for an elasticized warp knitted fabric which allows for greater flexibility in tailoring the modulus of the fabric to particular requirements.

According to a first aspect of the invention there is provided an elasticized warp knitted fabric comprising a group of front yarns knitted to form separate wales of pillar stitches, the wales being interconnected by at least one group of elastomeric rear yarns, the path of each elastomeric rear yarn between respective wales determining the modulus of the fabnc in a coursewise direction.

Interconnecting the separate wales of pillar stitches with elastomeric rear yarns introduces a coursewise elastomeric component to the structure of the fabric. The path of each elastomeric rear yarn between respective wales determines the number and density of such interconnections. Accordingly, by varying the path taken by the elastomeric rear yarns it is possible to alter the number and density of elastomeric interconnections between the wales, and thereby finely vary the nature of a coursewise elastomeric component. Varying the nature of the coursewise elastomeric component in this manner alters the extensibility and recovery, i.e. the modulus, of the fabric in the coursewise direction.

The range and variation of possible paths for each elastomeric rear yarn between respective wales allows for fine adjustment of the modulus of the fabric in a coursewise direction, and so allows for great flexibility in tailoring the modulus of the fabric according to particular requirements.

Preferably the group of front yarns are or include elastomeric yarns. The provision of elastomeric front yarns allows the fabric to extend in a walewise direction and imbues the fabric with a given modulus in the walewise direction. In addition, the separate wales of pillar stitches formed from elastomeric front yarns helps the fabric to lie flat when unconstrained.

Optionally each elastomeric rear yarn is knitted within a given wale for a plurality of courses. Such an arrangement reinforces each wale so as to improve the coursewise stability thereof. In addition this arrangement increases the quantity of elastomenc yarn extending in a walewise direction, and so increases the modulus of the fabric in a walewise direction.

In a preferred embodiment of the invention each elastomeric rear yarn is knitted within a given wale for seven courses.

In another preferred embodiment of the invention the path of each elastomeric rear yarn extends between three or more adjacent wales in a first direction and in a second direction, the first and second directions being opposite one another.

The foregoing arrangements provide elasticized warp knitted fabrics having an open structure which is desirably lightweight, as well as having desired transparency and breathability characteristics.

Preferably the warp knitted fabric includes first and second groups of elastomenc rear yarns. The inclusion of first and second groups of elastomeric rear yarns allows for still further flexibility in adjusting the modulus of the fabric in a coursewise direction.

The elastomeric rear yarns in the first and second groups may be knitted within alternate wales. Such an arrangement provides a fabric with an open structure having desirable weight, transparency and breathability characteristics.

in another embodiment of the invention the elastomeric rear yams in the first and second groups may be knitted within the same wales. Such a construction helps to further reinforce each wale.

Optionally the path of the elastomei-ic rear yarns in the first group is opposed to the path of the elastomeric rear yams in the second group. Paths of this type help the fabric to lie flat when unconstrained.

In a further preferred embodiment of the invention the elastomeric yarns are fused together. Having elastomenc yarns that are fused together helps to further stabilise the structure of the fabric.

According to a second aspect of the invention there is provided a process for producing an elasticized warp knitted fabric comprising the steps of: (a) threading a front bar of a warp knitting machine with a group of front yarns; (b) threading at least one rear bar of the knitting machine with a group ofelastomeric rear yams; (c) operating the front bar so as to form separate wales of pillar stitches; and (d) operatmg the or each rear bar to interconnect the wales by laying in the corresponding group of elastomeric rear yarns, the path of each elastomeric rear yarn between respective wales determining the moduius of the fabric in a coursewise direction.

The second aspect of the invention shares the advantages of the corresponding features of the first aspect of the invention.

Optionally threading the front bar includes threading the front bar for knitting at each needle position.

Preferably threading the or each rear bar includes threading the or each rear bar for knitting at alternate needle positions.

Threading the or each rear bar may mclude threading the or each rear bar for knitting at each needle position.

I

In another embodiment of the invention threading the front bar includes threading the front bar with elastomeric yarns.

In a further embodiment of the invention operating the or each rear bar includes lapping each elastomeric rear yarn about the same needle for a plurality of courses.

Preferably operating the or each rear bar includes lapping each elastomeric rear yarn about the same needle for seven courses.

Optionally operating the or each rear bar includes lapping each elastomeric rear yarn across at least three adjacent needles.

The process may include the step of threading first and second rear bars of the knitting machine with respective groups of elastomenc rear yarns.

in a still further embodiment of the invention the process includes the step of operating the first and second rear bars in opposition to one another.

The process may also include the step of fusing the elastomeric yarns together.

There now follows a brief description of preferred embodiments of the invention, by way of non-limiting example, with reference being made to the accompanying drawings in which: Figure 1(a) shows the structure of a conventional power net fabric; Figure 1(b) shows the lapping movements for producing the power net fabric shown in Figure 1(a); Figure 2(a) shows a schematic, partial view of the structure of an elasticized warp knitted fabric according to a first embodiment of the invention; Figure 2(b) shows the lapping movements for producing the elasticized warp knitted fabric shown in Figure 2(a); and Figure 3(a) shows a schematic, partial view of the structure of an elasticized warp knitted fabric according to a second embodiment of the invention.

An elasticized warp knitted fabnc according to a first embodiment of the invention is designated generally by the reference numeral 50.

The fabric 50 includes a group 52 of front yarns 54 (shown as dashed lines in Figure 2(a) for clarity) which are knitted to form separate wales 56 of pillar stitches 58. In the embodiment shown the pillar stitches 58 are open lap. In other embodiments different types of pillar stitch, including closed lap, are possible.

Each of the front yarns 54 in the first embodiment is an elastomeric yarn, and more particularly an elastane yarn. Other embodiments of the invention may include a group 52 of front yarns 54 which includes a different type of elastomeric yarn.

In preferred embodiments of the invention the elastomeric front yarns 54 have a yarn count in the range 44 to 156, and in especially preferred embodiments of the invention the e]astomeric front yarns 54 have a yarn count of 44 decitex.

The wales 56 of pillar stitches 58 are interconnected by a first group 60 of first elastomeric rear yarns 64, and by a second group 62 of second elastomeric rear yarns 66.

The first and second elastomeric rear yarns 64, 66 may have a yarn count in the range 44 to 570 decitex. In the first embodiment shown each of the elastomeric rear yarns 64, 66 is an elastane yarn having a yarn count of 78 decitex. In other embodiments of the invention the first elastomeric rear yarns 64 may be of a different type and have a different yarn count to the second elastomeric rear yarns 66.

Each elastomeric rear yarn 64, 66 is knitted within a given wale 56 for seven courses, and extends between three adjacent wales 56 in first and second directions, Other paths between respective wales 56 are also possible. For example each elastomeric rear yarn 64, 66 may be knitted within a given wale 56 for between 3 and 9 courses.

In the fabric 50 shown, the first elastomeric rear yarns 64 and the second elastomeric rear yarns 66 are knitted within alternate wales 56. In other embodiments of the invention, the first and second elastomeric rear yarns 64, 66 may be knitted within the same wales 56. or withm wales 56 spaced apart by more than one intermediate wale 56.

The path of each first elastomeric rear yarn 64 is opposed to the path of the corresponding second elastomeric rear yarn 66. Other embodiments of the invention may include first and second elastomeric rear yarns 64, 66 which are unopposed to one another, and so define an unsymmetrical fabnc structure.

Each of the elastomenc front yarns 54 and the first and second elastomeric rear yarns 64, 66 are fused together (not shown) where they intersect.

The first fabric SO includes respective pairs 68 of first and second elastomeric rear yarns 64, 66 extending between the wales 56. These rear yarn pairs 68 are spaced from one another by seven courses. This particular density of interconnections between the wales 56 gives rise to a corresponding coursewise elastomeric component which in turn determines the modulus of the fabric 50 in the coursewise direction.

To produce the first fabric 50 a front bar of a warp knitting machine is threaded with the group 52 of elastomeric front yarns 54 for knitting at each needle position, a first rear bar of the knitting machine is threaded with the first group 60 of first elastomeric rear yarns 64 for knitting at alternate needle positions, and a second rear bar of the knitting machine is threaded with the second group 62 of second elastomeric rear yarns 64 for knitting at alternate needle positions adjacent to the needle positions at which the first rear bar is knitting.

S

In other embodiments of the invention differing knitting configurations, such as a pair of half-set front bars, i.e. two front bars each of which is threaded for knitting at alternate needle positions, and a single full-set rear bar, i.e a rear bar which is threaded for knitting at each need position, are also possible.

The front bar is operated so as to form the separate wales 56 of open lap pillar stitches 58.

Meanwhile the first rear bar is operated to lay the first elastomeric yarns 64 into respective wales 56 of pillar stitches 58 by lapping each first elastomeric yarn 64 about a same first needle for seven courses, lapping across three adjacent needles in a first direction, lapping about a same second needle for a further seven courses, and lapping across three adjacent needles in a second direction opposite the first direction; and the second rear bar is operated to lay the second elastomeric yarns 66 into respective wales 56 of pillar stitches 58 b lapping each second elastomeric yarn 66 about a same third needle for seven courses, lapping across three adjacent needles in the second direction, lapping about a same fourth needle for a further seven courses, and lapping across three adjacent needles in the first direction.

The aforementioned lapping movements of the front bar, and each of the first and second rear bars are shown in Figure 2(b).

Following knitting of the first fabric SO, as set out above, the fabric SO is heat set to fuse the elastomeric yarns 54, 64, 66 together where they intersect.

In other embodiments of the mvention, the elasticized warp knitted fabric may be laminated to another fabric instead of being heat set.

An elasticized warp knitted fabric according to a second embodiment of the invention is designated generally by the reference numeral 100. The second fabric shares features with the first fabric 50 and these common features are designated using the same reference numerals.

S

The second fabric 100 includes a group 52 of elastomeric front yarns 54 (shown as dashed lines in Figure 3 for clanty) which are knitted to form separate wales 56 of open lap pillar stitches 58.

The wales 56 of pillar stitches 58 are interconnected by a first group 60 of first elastomeric rear yarns 64, and by a second group 62 of second elastomerie rear yarns 66.

The first and second elastoineric rear yarns 64, 66 are knitted within alternate wales, with each elastomeric rear yam 64, 66 being knitted within a given wale 56 for three courses, and extending between four adjacent wales 56 in first and second directions.

As with the first fabric 50, the path of each first elastomcric rear yarn 64 is opposed to the path of the corresponding second elastomeric rear yam 66, and all of the elastomei-ic yarns 54, 64, 66 are fused together (not shown) where they intersect.

The second fabric 100 includes a first formation 102 of two elastomeric rear yarns 64, 66, a second formation 104 of four elastomeric rear yarns 64, 66, with each of the formations 102, 104 extending between respective wales 56 to connect the wales 56 to one another.

The inclusion of second formations 104 including four elastomeric rear yarns 64, 66 provides the second fabric 100 with a greater density of elastomeric interconnections between the wales 56 than the first fabric 50.

In addition the formations 102, 104 in the second fabric 100 are more closely spaced in a walewise direction than the rear yarn pairs 68 of the first fabric 50.

This is because each elastomeric rear yam 64, 66 in the second fabric 100 is knitted within a given wale 56 for only three courses, rather than seven courses.

I

This increases still further the density of interconnections between the wales 56 of the second fabnc 100 compared to that of the first fabric 50.

Accordingly, by varying the path of each elastomeric rear yarn 64, 66 between respective wales it is possible to alter the density of elastomeric interconnections between the wales 56 in the second fabric 100. in this instance the density of elastomeric connections between the wales 56 is increased.

Increasing the density of elastomenc interconnecnons between the wales 56 in the second fabric 100 increases the magnitude of the corresponding coursewise elastomeric component, and thereby increases the modulus of the second fabric in the coursewise direction. Accordingly the second fabric 100 has a greater modulus in the coursewise direction than the first fabric 50.

Claims

CLAIMS: 1. An elasticized warp knitted fabric comprising a group of front yarns knitted to form separate wales of pillar stitches, the wales being interconnected by at least one group of elastomeric rear yarns, the path of each elastomeric rear yarn between respective wales determining the modulus of the fabne in a coursewise direction.
2. An elasticized warp knitted fabric according to Claim I wherein the group of front yams are or include elastomeric yarns.
3. An elasticized warp knitted fabric according to Claim I or Claim 2 wherein each elastomeric rear yarn is knitted within a given wale for a plurality of courses.
4. An elasticized warp knitted fabric according to Claim 3 wherein each elastomeric rear yam is knitted within a given wale for seven courses.
5. An elasticized warp knitted fabric according to any preceding claim wherein the path of each elastomenc rear yam extends between three or more adjacent wales in a first direction and in a second direction, the first and second directions being opposite one another.
6. An elasticized warp knitted fabric according to any preceding claim including first and second groups of elastomeric rear yarns.
7. An elasticized warp knitted fabric according to Claim 6 wherein the elastomenc rear yarns in the first and second groups are knitted within alternate wales.
8. An elasticized warp knitted fabric according to Claim 6 wherein the elastomeric rear yarns in the first and second groups are knitted within the same wales.
9. An elasticized warp knitted fabric according to any of Claims 6 to 8 wherein the path of the elastomeric rear yams in the first group is opposed to the path of the elastomeric rear yarns in the second group.
10. An elasticized warp knitted fabric according to any preceding claims wherein the elastomeric yarns are fused together.
II. A process for producing an elasticized warp knitted fabric comprising the steps of: (a) threading a front bar of a warp knitting machine with a group of front yarns; (b) threading at least one rear bar of the knitting machine with a group of elastomeric rear yarns; (c) operating the front bar so as to form separate wales of pillar stitches, and (d) operating the or each rear bar to interconnect the wales by laying in the corresponding group of elastomeric rear yarns, the path of each elastomeric rear yam between respective wales determining the modulus of the fabric in a coursewise direction.
12. A process for producing an elasticized warp knitted fabric according to Claim 11 wherein threading the front bar includes threading the front bar for knitting at each needle position.
13. A process for producing an elasticized warp knitted fabric according to Claim 11 or Claim 12 wherein threading the or each rear bar includes threading the or each rear bar for knitting at alternate needle positions.
14. A process for producing an elasticized warp knitted fabric according to Claim 11 or Claim 12 wherein threading the or each rear bar includes threading the or each rear bar for knitting at each needle position.
15. A process for producing an elasticized warp knitted fabnc according to any of Claims 11 to 14 wherein threading the front bar includes threading the front bar with elastomeric yarns.
16. A process for producing an elasticized warp knitted fabric according to any of Claims 11 to 15 wherein operating the or each rear bar includes lapping each elastomeric rear yarn about the same needle for a plurality of courses.
17. A process for producing an elasticized warp knitted fabric according to rn Claim 16 wherein operating the or each rear bar includes lapping each elastomenc rear yarn about the same needle for seven courses.
18. A process for producing an elasticized warp knitted fabric according to any of Claims 11 to 17 wherein operating the or each rear bar includes lapping each elastomeric rear yarn across at least three adjacent needles.
19. A process for producing an elasticized warp knitted fabric according to any of Claims 11 to 17 including the step of threading first and second rear bars of the knitting machine with respective groups of elastomeric rear yams.
20. A process for producing an elasticized warp knitted fabric according to Claim 19 including the step of operating the first and second rear bars in opposition to one another.
21. A process for producing an elasticized warp knitted fabric according to any of Claims Ii to 20 further including the step of fusing the elastomeric yarns together.
22. A garment comprising an elasticized warp knitted fabric according to any of Claims ito 9.
23. A composite fabric comprising an elasticized warp knitted fabric according to any of Claims 1 to 9.
24. An elasticized warp knitted fabric generally as herein described with reference to and/or as illustrated in Figures 2(a) to 3 of the accompanying drawings.
25. A process for producing an elasticized warp knitted fabric generally as herein described with reference to and/or as illustrated in Figures 2(a) to 3 the accompanying drawings