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Title:
WARP KNITTED FABRIC AND STRETCHABLE ARTICLE
Document Type and Number:
WIPO Patent Application WO/2021/053431
Kind Code:
A1
Abstract:
A warp knitted fabric according to an embodiment includes: a plurality of warps having stretchability and arranged along a weft direction; and a weft having non-stretchability, where the weft 3 is arranged to meander between the plurality of warps, and the weft forms a folding back part with any of the plurality of warps and forms a loop folding back part that is a closed loop with any of the plurality of warps.

Inventors:
MORISHITA KENICHIRO (JP)
Application Number:
IB2020/057838
Publication Date:
March 25, 2021
Filing Date:
August 20, 2020
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
3M INNOVATIVE PROPERTIES CO (US)
International Classes:
D04B21/18; A41B17/00; A47G9/02; D04B21/00
Foreign References:
JP2008075241A2008-04-03
JPH04263657A1992-09-18
JP2004100117A2004-04-02
JPH03152252A1991-06-28
JP2008106382A2008-05-08
Attorney, Agent or Firm:
BAUM, Scott A., et al. (Office of Intellectual Property CounselPost Office Box 3342, Saint Paul Minnesota, US)
Download PDF:
Claims:
WHAT IS CLAIMED IS:

1. A warp knitted fabric comprising: a plurality of warps having stretchability and arranged along a weft direction; and a weft having non-stretchability, wherein the weft forms a folding back part with respect to the warp positioned on each of both end sides in the weft direction among the plurality of warps, and the weft forms a closed loop with the warp positioned on a center side in the weft direction among the plurality of warps.

2. The warp knitted fabric according to claim 1, wherein the weft straddles at least three of the warps.

3. The warp knitted fabric according to claim 1 or 2, wherein the weft forms a non-loop folding back part that is folded back without forming a loop with respect to the warp positioned on each of both end sides in the weft direction among the plurality of warps.

4. A warp knitted fabric, comprising: a plurality of warps having stretchability and arranged along a weft direction; and a weft having non-stretchability, wherein the weft is arranged to meander between the plurality of warps, and the weft forms a folding back part with any of the plurality of warps and forms a closed loop with any of the plurality of warps.

5. The warp knitted fabric according to claim 4, wherein the closed loop and the folding back part are provided alternately.

6. The warp knitted fabric according to claim 4 or 5, wherein the weft straddles two of the warps, and the weft forms the folding back part with respect to one of the two of the warps and forms the closed loop with respect to the other of the two of the warps.

7. A stretchable article comprising the warp knitted fabric described in any one of claims 1 to 6, wherein the stretchable article constitutes any of a sanitary article, a medical article, sports goods, underwear, and bedding.

Description:
WARP KNITTED FABRIC AND STRETCHABLE ARTICLE

One aspect of the present disclosure relates to a warp knitted fabric and a stretchable article.

BACKGROUND

JP 2018-131718A discloses a warp knitted fabric including a first yarn, a second yarn, and a third yam. The first yarn and the second yam are elastic yarns, and the third yarn is a non-elastic yarn. The swing width of the first yam (the number of straddling yams) is smaller than the swing width of the second yarn and the swing width of the third yam. That is, the first yarn is an elastic yam having a relatively small swing width, the second yam is an elastic yarn having a relatively large swing width, and the third yam is a non-elastic yarn having a relatively large swing width. In this warp knitted fabric, by combining three types of yams such as a first yarn, a second yam, and a third yam, stretchability in the warp direction is increased, stretchability in the weft direction is decreased, and curling is suppressed.

SUMMARY

The warp knitted fabric used in the stretchable article is required to be thin and light in order to improve air permeability while enhancing stretchability in one direction. However, when the warp knitted fabric is made thin and light by reducing the number of yarns to be used or reducing the density of the yarns, it is assumed that curling or yarn twisting occurs or splitting occurs. Therefore, the warp knitted fabric is required to be thin and light while maintaining strength.

A warp knitted fabric according to an aspect of the present disclosure includes: a plurality of warps having stretchability and arranged along a weft direction; and a weft having non-stretchability, where the weft forms a folding back part with respect to the warp positioned on each of both end sides in the weft direction among the plurality of warps, and the weft forms a closed loop with the warp positioned on a center side in the weft direction among the plurality of warps. Since the warp knitted fabric includes a weft having non-stretchability and a plurality of warp having stretchability, high stretchability in the warp direction can be realized, and the warp knitted fabric can be made thin and light by combining two types of yarns and setting the number of knitting patterns of the yarns to two. In the present disclosure, the “type of yam” indicates the type of yarn thickness, yam material, or the like, and the “pattern” indicates the type of yarn knitting mode. Even when the plurality of “patterns” are the same as each other, the “types of yarns” used as the patterns may be different from each other. In the warp knitted fabric described above, the weft forms the folding back parts with the warps positioned on both end sides in the weft direction among the plurality of warps and forms the closed loop with the warp positioned on the center side in the weft direction. In the present disclosure, the “folding back part” indicates a pattern where one of the two yarns is directed toward the other yarn and folded back away from the other yarn. The “closed loop” indicates a pattern in which the yam forms a loop (ring-shaped part) of 360° (one round) or more. As described above, the non-stretchable weft forms folding back parts with the warps on both end sides in the weft direction and forms a closed loop with the warp on the center side in the weft direction, whereby the strength of the warp knitted fabric can be increased by the two types of yarns. Further, by forming two patterns of a folding back part and a closed loop by a plurality of warps and wefts, the warp knitted fabric can be made light and thin while increasing the strength.

The weft may straddle at least three warps.

The weft may form a non-loop folding back part that is folded back without forming a loop with respect to the warp positioned on each of both end sides in the weft direction among the plurality of warps.

A warp knitted fabric according to another aspect of the present disclosure includes: a plurality of warps having stretchability and arranged along a weft direction; and a weft having non-stretchability, where the weft is arranged to meander between the plurality of warps, and the weft forms a folding back part with any of the plurality of warps and forms a closed loop with any of the plurality of warps.

In this warp knitted fabric, the weft forms a folding back part with respect to any of the plurality of warps and forms a closed loop with any of the plurality of warps. Therefore, the weft forms both of the folding back part and the closed loop for each of the plurality of yarns, whereby the strength of the warp knitted fabric can be increased by the two types of yarns. In this warp knitted fabric, as described above, since the weft has non-stretchability and the plurality of warps have stretchability, the warp knitted fabric can be made thin and light by two patterns formed by two types of yarns, and high stretchability in the warp direction can be realized.

The closed loop and the folding back part may be provided alternately.

The weft may straddle two warps, and the weft may form a folding back part with respect to one of the two warps and form a closed loop with the other of the two warps.

A stretchable article according to an aspect of the present disclosure is a stretchable article including the above-described warp knitted fabric and constitutes any of a sanitary article, a medical article, sports goods, underwear, and bedding. Since the stretchable article includes the above-described warp knitted fabric, the stretchable article exhibits the same acting-effects as those of the above-described warp knitted fabric.

According to one aspect of the present disclosure, it is possible to reduce the thickness and weight while maintaining the strength.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. l is a view illustrating a warp knitted fabric according to an embodiment.

FIG. 2 is a view illustrating an example in which the warp knitted fabric of FIG. 1 is stretched in the warp direction.

FIG. 3 is a diagram illustrating an exemplary knitting structure of warps and wefts of the warp knitted fabric of FIG. 1.

FIG. 4 is a schematic enlarged view of a closed loop of the weft in the knitting structure of FIG. 3.

FIG. 5 is a schematic enlarged view of another closed loop of the weft in the knitting structure of FIG. 3.

FIG. 6 is a diagram illustrating a knitting structure of warps and wefts of a warp knitted fabric according to a modified example.

FIG. 7 is a diagram illustrating a knitting structure of warps and wefts of a warp knitted fabric according to another modified example.

FIG. 8 is a diagram illustrating a knitting structure of warps and wefts of a warp knitted fabric according to still another modified example. FIG. 9 is a diagram illustrating a knitting structure of warps and wefts of a warp knitted fabric according to a comparative example.

FIG. 10 is a diagram illustrating a knitting structure of warps and wefts of a warp knitted fabric according to another comparative example.

FIG. 11 is a diagram illustrating a knitting structure of warps and wefts of a warp knitted fabric according to still another comparative example.

FIG. 12 is a graph showing the results of tensile tests performed on warp knitted fabrics according to examples and comparative examples.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of a warp knitted fabric and a stretchable article according to the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are denoted by the same reference signs, and redundant description is omitted as appropriate. The drawings may be partially simplified or exaggerated for ease of understanding, and the dimensional ratios, etc. are not limited to those illustrated in the drawings.

FIGS. 1 and 2 are views schematically illustrating a warp knitted fabric 1 according to an embodiment. As illustrated in FIGS. 1 and 2, the warp knitted fabric 1 is a stretchable warp knitted fabric extending in a warp direction D1 and a weft direction D2 and has high stretchability in the warp direction Dl. The warp direction D1 is, for example, a machine direction (MD) in which the warp knitted fabric 1 is fed, and the weft direction D2 is a cross direction (CD) orthogonal to the MD.

The warp knitted fabric 1 is, for example, a stretchable warp knitted fabric that hardly stretches in the weft direction D2 but stretches in the warp direction Dl orthogonal to the weft direction D2. The density of the warp knitted fabric 1 in the warp direction Dl is, for example, 15 yarns/inch or more and 25 yarns/inch or less and is, for example, 20 yarns/inch. The weight per unit area of the warp knitted fabric 1 is, for example, 25 gsm or more and 32 gsm or less and is, for example, 26 gsm. The air permeability of the warp knitted fabric 1 is, for example, 195 (cm 3 /cm 2 s) or more and 800 (cm 3 /cm 2 s) or less and may be, for example, 200 (cm 3 /cm 2 s).

The warp knitted fabric 1 is, for example, a fabric included in a stretchable article constituting any of the followings: an absorbent article such as a diaper, a napkin, or an incontinence pad; a sanitary article including a sanitary material such as a hemostatic tape; a medical article; sports goods; underwear; and bedding. As a specific example, the warp knitted fabric 1 may be used as an elastomeric core layer in the waist or legs of a diaper. The warp knitted fabric 1 may be used for any of fitness wear, leotard, spats, legwear, innerwear, sportswear, sports inner, and swimwear.

The warp knitted fabric includes: a plurality of folding back parts formed by a plurality of yarns; and a plurality of loops including open loops and closed loops. The “folding back part” indicates a portion where one of the two yarns is directed toward the other yam and folded back away from the other yarn. The “loop” indicates a ring-shaped part formed by the yarn, the “closed loop” indicates a loop in which the yarn circulates one or more times, and the “open loop” indicates a loop in which the yarn does not circulate (e.g., a part in which the yarn is U-shaped). A “non-loop folding back part” described later indicates a folding back part that does not form a loop. The “folding back part” includes both a non-loop folding back part and a folding back part forming a loop (hereinafter sometimes referred to as a loop folding back part).

FIG. 3 is a diagram illustrating the knitting structure of the warp knitted fabric 1. As illustrated in FIG. 3, for example, the warp knitted fabric 1 includes a warp 2 that is a stretchable front yarn and a weft 3 that is a non-stretchable back yam and is formed of two types of yams. The warp 2 is an elastic yarn and the weft 3 is an inelastic yarn. The swing width of the warp 2 is smaller than the swing width of the weft 3, for example. Accordingly, high stretchability in the warp direction D1 by the warps 2 is exhibited, and high stretchability in the warp direction D1 is realized.

The thickness (weight per unit) of the warp 2 is, for example, 44T (decitex) or 22T. The warps 2 are arranged along the weft direction D2. The warp 2 includes, for example, an open loop 2b and a closed loop 2c, and the open loop 2b and the closed loop 2c are alternately arranged along the warp direction D1. The thickness (weight per unit) of the weft 3 is, for example, 22T. The weft 3 is arranged so as to meander between a plurality of the warps 2, and straddles the plurality of warps 2. As an example, the weft 3 forms a closed loop 10, 20 with an open loop 2b of the warp 2 and forms a folding back part 30 with respect to a closed loop 2c of the warp 2.

The material of the warp 2 is, for example, a polyurethane. However, the material of the warp 2 may be a polyether ester and can be appropriately changed. The material of the weft 3 includes, for example, at least one of polyethylene terephthalate, nylon, polypropylene, polyester, polyolefin, polyamide, acrylic, cellulose, wool, and linen. The knitting structure of the warp 2 is, for example, 0-1/1 -0/ 1 -0/0- 1 , and the knitting structure of the weft 3 is 3-2/5-5/2-3/0-0.

The warp knitted fabric 1 includes, for example, a plurality of the closed loops 10, 20 and a plurality of the folding back parts 30. The weft 3 forms, for example, the closed loops 10, 20 and the folding back parts 30 alternately. As a specific example, the weft 3 may form the closed loop 10, the folding back part 30, the closed loop 20, and the folding back part 30 in this order. The folding back part 30 is formed with respect to the warp 2 positioned on each of both end sides in the weft direction D2 among the plurality of warps 2. The folding back part 30 is, for example, a non-loop folding back part. That is, at the folding back part 30, the weft 3 is folded around the warp 2 without forming a ring-shaped part.

The closed loop 10, 20 of the weft 3 is formed with the warp 2 positioned on the center side in the weft direction D2 among the plurality of warps 2. As an example, the weft 3 straddles three warps 2. In this case, the weft 3 forms the folding back part 30 with respect to each of the two warps 2 positioned at both ends in the weft direction D2 and forms the closed loop 10, 20 with respect to the one warp 2 positioned at the center in the weft direction D2.

FIG. 4 is an enlarged view of the open loop 2b of the warp 2 and the closed loop 10 of the weft 3. As illustrated in FIG. 4, the closed loop 10 is formed by the weft 3 entwining the open loop 2b of the warp 2. As an example, the closed loop 10 is formed by the weft 3 extending in an oblique direction D3 with respect to the warp 2, passing under the warp 2 to reach the open loop 2b of the warp 2, passing over the warp 2 while circulating in one direction (e.g., clockwise), and coming out in the oblique direction D3.

FIG. 5 is an enlarged view of the open loop 2b of the warp 2 and the closed loop 20 of the weft 3. As illustrated in FIG. 5, the closed loop 20 is opposite to the closed loop 10 in the weft direction D2. As an example, the closed loop 20 is formed by the weft 3 extending in an oblique direction D4 with respect to the warp 2, passing under the warp 2 to reach the open loop 2b of the warp 2, passing over the warp 2 while circulating in a direction opposite to the one direction described above (e.g., counterclockwise), and coming out in the oblique direction D4. The oblique direction D4 is a direction intersecting the oblique direction D3, and is orthogonal to the oblique direction D3, for example. A knitting structure of a warp knitted fabric 1A according to a modified example will be described with reference to FIG. 6. Since a part of the warp knitted fabric according to the following modified examples overlaps with a part of the warp knitted fabric 1 described above, the description of the content overlapping with the warp knitted fabric 1 is appropriately omitted. As illustrated in FIG. 6, the warp knitted fabric 1A includes the plurality of warps 2 and the weft 3, and the configuration of the plurality of warps 2 is the same as that of the warp knitted fabric 1 described above. Further, the orientation of the weft 3 in the warp knitted fabric 1 A is an orientation in which the orientation of the weft 3 in the warp knitted fabric 1 is reversed. In the warp knitted fabric 1 A, the knitting structure of the warp 2 is 0-1/1 -0/ 1 -0/0- 1 , and the knitting structure of the weft 3 is 2-3/0-0/3-2/5-5.

Next, acting-effects of the warp knitted fabric 1, 1A described above will be described.

Since the warp knitted fabric 1, 1 A includes the weft 3 having non-stretchability and the plurality of warps 2 having stretchability, high stretchability in the warp direction D1 can be realized, and the warp knitted fabric 1, 1 A can be made thin and light by setting the number of knitting patterns of the yams to two. From the viewpoint of reducing the thickness and weight of the warp knitted fabric, it is not desirable that the number of knitting patterns is three or more in some cases. However, in the warp knitted fabric 1, 1A, the number of patterns is two, which can make the warp knitted fabric 1, 1A light and thin. That is, the weft 3 forms the folding back part 30 with respect to the warps 2 positioned on both end sides in the weft direction D2 among the plurality of warps 2 and forms the closed loop 10, 20 with the warp 2 positioned on the center side in the weft direction D2. As described above, the non-stretchable weft 3 forms the folding back part 30 with respect to the warps 2 at both ends in the weft direction D2 and forms the closed loop 10, 20 with the warp 2 on the center side in the weft direction D2, whereby the strength of the warp knitted fabric 1, 1A can be increased by the two types of yarns. Further, by forming two patterns of the folding back part 30 and the closed loops 10, 20 by the plurality of warps 2 and the weft 3, the warp knitted fabric 1, 1A can be made light and thin while increasing the strength. In the stretchable article including the warp knitted fabric 1, 1A, the same acting-effect as described above can be obtained. The weft 3 may straddle at least three warps 2. In this case, since the weft 3 straddles three or more warps 2 along the weft direction D2, the strength of the warp knitted fabric 1, 1 A in the warp direction D1 can be increased.

The weft 3 may form a non-folding back loop (folding back part 30) that is folded back without forming a loop with respect to the warp 2 positioned on each of both end sides in the weft direction D2 among the plurality of warps 2. Here, “the warp 2 positioned on each of both end sides in the weft direction D2 among the plurality of warps 2” indicate the warps 2 positioned on both ends in the weft direction D2 among the plurality of warps 2 straddled by the weft 3. In this case, since the weft 3 does not form a loop at the folding back part 30, the stretchability of the warp knitted fabric 1, 1 A in the warp direction D1 can be enhanced.

The closed loop 10, 20 and the folding back part 30 may be alternately provided. In this case, the strength of the warp knitted fabric 1, 1A and the stretchability in the warp direction D1 can be improved, and the configuration of the warp knitted fabric 1, 1 A can be simplified.

Next, a knitting structure of a warp knitted fabric IB according to another modified example will be described with reference to FIG. 7. As illustrated in FIG. 7, in the warp knitted fabric IB, the weft 3 forms a loop folding back part 40 that is folded back by forming a loop with respect to the closed loop 2c of the warp 2. In the loop folding back part 40, for example, a closed loop is formed by the weft 3. In the warp knitted fabric IB, the knitting structure of the warp 2 is, for example, 0-1/1-0/1-0/0-1, and the knitting structure of the weft 3 is 3-2/5-4/2-3/0-1.

The loop folding back part 40 of the weft 3 is formed with respect to the closed loop 2c of the warp 2 positioned on each of both end sides in the weft direction D2 among the plurality of warps 2. As an example, the weft 3 forms the loop folding back part 40 with respect to each of the two warps 2 positioned at both ends in the weft direction D2. The warp knitted fabric 1 includes the plurality of closed loops 10, 20 and a plurality of the loop folding back parts 40. The weft 3 forms, for example, the closed loop 10, the loop folding back part 40, the closed loop 20, and the loop folding back part 40 in this order.

As described above, in the warp knitted fabric IB, since the weft 3 forms the loop folding back parts 40 with respect to the warps 2 positioned at both ends in the weft direction D2, the warp knitted fabric IB can be made thin and light, and the strength of the warp knitted fabric IB can be further increased while maintaining stretchability in the warp direction Dl.

A warp knitted fabric 1C according to still another modified example will be described with reference to FIG. 8. As illustrated in FIG. 8, the weft 3 straddles two warps 2. The weft 3 forms the loop folding back part 40 with respect to the open loop 2b of the warp 2, and forms a folding back part 30 with respect to the closed loop 2c of the warp 2. For example, the loop folding back part 40 is a closed loop, and the folding back part 30 is a non-loop folding back part.

As described above, the warp knitted fabric 1C includes the plurality of folding back parts 30 and the plurality of loop folding back parts 40. For example, the weft 3 alternately forms the folding back part 30 and the loop folding back part 40. The weft 3 forms the folding back part 30 for one of the two warps 2, and forms the loop folding back part 40 for the other of the two warps 2. In the warp knitted fabric 1C, for example, the knitting structure of the warp 2 is 0-1/1-0/1-0/0-1, and the knitting structure of the weft 3 is 2-3/5-5.

In the warp knitted fabric 1C, the weft 3 may form the folding back part 30 with any of the plurality of warps 2 and may form the loop folding back part 40, which is a closed loop, with any of the plurality of warps 2. That is, as illustrated in FIG. 8, the weft 3 may form the folding back part 30 in one warp 2 and the weft 3 may form the loop folding back part 40 in another warp 2, or the weft 3 may form both the folding back part 30 and the loop folding back part 40 in the one warp 2. As described above, since the plurality of warps 2 and a plurality of the wefts 3 form both the folding back part 30 and the closed loop, the strength of the warp knitted fabric 1C can be increased by the two types of yarns. As described above, since the weft 3 is non-stretchable and the plurality of warps 2 are stretchable, the warp knitted fabric 1C can be made thin and light by the two types of yarns, and high stretchability in the warp direction can be realized.

The closed loop (loop folding back part 40) and the folding back part 30 may be alternately provided. In this case, both the improvement in the strength of the warp knitted fabric 1 and the improvement in the stretchability in the warp direction Dl can be realized, and the configuration of the warp knitted fabric 1C can be simplified.

Furthermore, as in the warp knitted fabric 1C, the weft 3 may straddle the two warps 2, and the weft 3 may form the folding back part 30 with respect to one of the two warps 2 and may form a closed loop with respect to the other of the two warps 2. In this case, the strength of the warp knitted fabric 1C can be maintained, and the configuration of the warp knitted fabric 1C can be further simplified.

The embodiments and the modified examples of the warp knitted fabric and the stretchable article according to the present disclosure have been described above. However, the present invention is not limited to the above-described embodiments and the modified examples. The present invention can be variously modified without departing from the gist described in the claims. For example, the shape, thickness, material, number, and arrangement of the yarns constituting the warp knitted fabric can be appropriately changed within the scope of the above-described gist.

(Examples)

Next, examples of the warp knitted fabric will be described. The present invention is not limited to the following examples. In the experiment according to the examples, the warp knitted fabrics of Examples 1 to 4 and Comparative Examples 1 to 3 described later were subjected to a tensile test, and the tensile stress and the elongation rate were measured. In the tensile test, the tensile stress at 200% elongation of the warp knitted fabric was measured in accordance with JIS K 7127, and each warp knitted fabric was pulled in the warp direction (MD) at a test piece width of 25 mm, a chuck interval of 25 mm, and a test speed of 300 mm/min.

Example 1

The warp knitted fabric according to Example 1 had a knitting structure similar to that of the warp knitted fabric 1 illustrated in FIG. 3, the material of the warp 2 having stretchability was polyurethane, and the thickness of the warp 2 was 44T. The material of the weft 3 having non-stretchability was polyethylene terephthalate, and the thickness of the weft 3 was 22T. The knitting structure of the warp 2 was 0-1/1 -0/1 -0/0-1, and the knitting structure of the weft 3 was 3-2/5-5/2-3/0-0. In each of subsequent Examples 2 to 4 and Comparative Example 1, 2, the material and thickness of the warp 2 and the material and thickness of the weft 3 were the same as those in Example 1.

Example 2

The warp knitted fabric according to Example 2 had the same knitting structure as that of the warp knitted fabric 1 A illustrated in FIG. 6, and the knitting structure of the warp 2 was 0-1/1-0/1-0/0-1, and the knitting structure of the weft 3 was 2-3/0-0/3-2/5-5. Example 3 The warp knitted fabric according to Example 3 had the same knitting structure as that of the warp knitted fabric IB illustrated in FIG. 7, and the knitting structure of the warp

2 was 0-1/1-0/1-0/0-1, and the knitting structure of the weft 3 was 3-2/5-4/2-3/0-1. Example 4

The warp knitted fabric according to Example 4 had the same knitting structure as the warp knitted fabric 1C illustrated in FIG. 8, and the knitting structure of the warp 2 was 1-0/0-1, and the knitting structure of the weft 3 was 3-3/1-0.

Comparative Example 1

In the warp knitted fabric according to Comparative Example 1, as illustrated in FIG.

9, the weft 3 straddles two warps 2. The weft 3 has only loop folding back parts 40 which are closed loops and does not have non-loop folding back parts. The knitting structure of the warp 2 was 0-1/1-0, and the knitting structure of the weft 3 was 1-0/2-3.

Comparative Example 2

In the warp knitted fabric according to Comparative Example 2, as illustrated in FIG.

10, the weft 3 straddles two warps 2. The weft 3 has only folding back parts 30 which are non-loop folding back parts and does not have closed loops. The knitting structure of the warp 2 was 1 -0/1-0, and the knitting structure of the weft 3 was 0-0/3 -3.

Comparative Example 3

As illustrated in FIG. 11, the warp knitted fabric according to Comparative Example

3 included three types of yarns, namely, the warp 2, the weft 3, and a second weft 103. In FIG. 11, the scale of the warp knitted fabric in the weft direction is different from those in FIG. 3 or FIGS. 6 to 10. The material of the warp 2 was polyurethane, the material of the weft 3 was polyethylene terephthalate, and the material of the second weft 103 was polyurethane. The knitting structure of the warp 2 was 0-1/1-0, the knitting structure of the weft 3 was 0-1/3 -2, and the knitting structure of the second weft 103 was 0-0/3 -3.

FIG. 12 shows the results of tensile tests performed on Examples 1 to 4 and Comparative Examples 1 to 3. FIG. 12 is a graph showing the relationship between elongation rate and tensile strength for each of Examples 1 to 4 and Comparative Examples 1 to 3. As illustrated in FIG. 12, it was found that the warp knitted fabric according to Comparative Example 3 cannot be stretched long in the MD (warp direction Dl) under the same tensile stress (cannot be stretched long unless the tensile stress is large) as compared with other warp knitted fabrics. In contrast, it was found that each of the warp knitted fabrics of Examples 1 to 4 and Comparative Examples 1, 2 could be stretched long in the MD with a small tensile stress.

In the warp knitted fabric of Comparative Example 1 in which the weft 3 straddling the two warps 2 did not have a non-loop folding back part, the warp knitted fabric could be stretched long with a small tensile stress, but stretching unevenness and yarn twisting occurred during stretching. In addition, in the warp knitted fabric of Comparative Example 2 in which the weft 3 straddling two warps 2 did not have a closed loop, splitting in the MD occurred during stretching.

On the other hand, in each of the warp knitted fabrics of the followings: Example 1 and Example 2 in which the weft 3 straddles three warps 2 had a non-loop folding back part and a closed loop; Example 3 in which the weft 3 straddling three warps 2 had a closed loop; and Example 4 in which the weft 3 straddling two warps 2 had a non-loop folding back part and a closed loop, stretching unevenness, yarn twisting, and splitting did not occur. In addition, it was found that, in the warp knitted fabrics of Examples 1 to 4, it was possible to suppress abnormalities such as stretching unevenness that may occur when stretched and that it was possible to elongate the warp knitted fabrics in the MD with a small tensile stress. Further, the result was obtained that the warp knitted fabric of Example 4 was curled (bent), and the warp knitted fabric of Example 3 was slightly curled, but the warp knitted fabrics of Examples 1 and 2 were hardly curled.

REFERENCE SIGNS LIST

1, 1A, IB, 1C: Warp knitted fabric, 2: Warp, 2b: Open loop, 2c: Closed loop, 3: Weft, 10, 20: Closed loop, 30: Folding back part, 40: Loop folding back part (Closed loop), Dl: Warp direction, D2: Weft direction, D3, D4: Oblique direction