CN113383120A

CN113383120A - Open mesh leno fabric, bag made therefrom and method of making leno fabric

Info

Publication number: CN113383120A
Application number: CN202080011528.2A
Authority: CN
Inventors: 悉达尔斯·罗希亚
Original assignee: Lohia Corp Ltd
Current assignee: Lohia Corp Ltd
Priority date: 2019-02-03
Filing date: 2020-01-24
Publication date: 2021-09-10
Also published as: WO2020157613A1; TW202039948A; ZA202105401B; PE20211841A1; MX2021008481A; BR112021015341A2; TWI785306B

Abstract

The present invention relates to the production of bags for packaging and storing goods. More particularly, the invention relates to flat or tubular leno woven fabrics consisting of at least one warp (6A) with a strand (6B or 6C) made of bulked yarn as weft yarn and/or at least one weft (5A) made of bulked yarn, and bags made of such fabrics. The invention solves the problem of coarseness of leno-woven fabrics made of hard yarns, in particular for perishable goods and other goods that may be damaged by rough packaging. Woven fabrics typically include a warp structure and a weft structure formed using warp and weft yarns, respectively. Woven strip film strip fabrics typically comprise two sets of threads arranged in a warp and weft configuration. The thread is typically made from a plurality of strips of film. The fabric of the present invention incorporates some of the texturizing yarns in the weave pattern to make the fabric softer than conventional fabrics. This critical aspect of the invention makes the bag less rugged for cargo than bags made of conventional leno fabrics made of hard yarns.

Description

Open mesh leno fabric, bag made therefrom and method of making leno fabric

Technical Field

The present invention relates to the production of bags for packaging and storing goods. More particularly, the present invention relates to packaging and storing perishable agricultural products (produce). More particularly, the invention relates to bags made of flat or tubular fabric consisting of at least one bulky yarn as weft and at least one combination of bulky yarn and hard yarn as warp, wherein the weft yarns are held in place with each other by leno weaving.

Background

Typically, open mesh leno bags for packaging different produce such as potatoes, onions, fruits, flowers and the like are made from a narrow strip of film of polyethylene or polypropylene material. The strip of film tape material imparts the desired breathability or openness to the fabric bag, however, the rough edges of the tape give a rough feel upon contact which may damage the more delicate perishable produce. Furthermore, the dimensional stability of the fabric is impaired by the slippery nature of the strip of film strip, so that the bag cannot retain its shape during handling of the bag.

Further, to improve the softness of the fabric and the resulting bag, if only multifilament yarns are used in the manufacture of the leno bags, there are more dimensional stability problems during bag processing, goods packaging and bag storage. Accordingly, there is a need to improve the structure of the bag to provide flexibility and dimensional stability.

Disclosure of Invention

One of the objects of the present invention is to provide flexibility to the bag contents and sufficient coverage with the desired breathability/openness.

It is another object of the present invention to provide rigidity to the bag structure, imparting dimensional stability to the bag and its contents.

It is another object of the present invention to provide a fabric structure suitable for automated bag processing.

Drawings

FIG. 1A: leno tubular fabric of prior art

FIG. 1B: magnified view of prior art leno fabric structure

FIG. 2: leno tubular fabric of the invention

Fig. 2A, 2B, and 2C: some weave patterns covered by the scope of the invention

Fig. 3A, 3B, and 3C: some other weave patterns covered by the scope of the invention

Fig. 4A and 4B: more numerous weave patterns are covered by the scope of the invention

Fig. 5A, 5B, and 5C: the scope of the invention covers further weave patterns

Fig. 6A, 6B, and 6C: still other weave patterns are covered by the scope of the invention

Fig. 7A, 7B, and 7C: some other weave patterns covered by the scope of the invention

List of parts:

1: leno tubular fabric of prior art

2: weft narrow strip film strip (prior art)

3: longitudinal strip film belt

4: leno tubular fabric of the invention

5: weft yarn structure 5A: weft/shute

6: warp structure, 6A: warp/warp yarns; 6B and 6C- -two warp strands constituting a warp

7: bulked yarn

8: hard yarn

L: winding ring

Detailed Description

Woven fabrics typically include a warp structure and a weft structure formed using warp and weft yarns, respectively. Woven strip film strip fabrics typically comprise two sets of threads arranged in a warp and weft configuration. The yarn is typically made from a plurality of strips of film. The yarns of any one set (warp or fill) are arranged parallel to each other and interweave with the yarns of the second set (fill or warp). The yarns of one set are oriented substantially at right angles to the yarns of the other set. For a simple plain weave, the warp threads pass over and under the weft threads in an alternating manner. In particular, for a given warp thread to pass over a particular weft thread, an adjacent warp thread will pass under that particular weft thread, thereby locking the weft thread in place. A limitation of plain weave fabrics is the lack of porosity or openness.

A typical leno weave is different from a plain weave. In leno weaving, the warp structure (6) is made of warp threads (6A), which warp threads (6A) in turn have warp thread strands (6B, 6C) grouped in pairs. The weft structure (5) comprises weft threads (5A) interwoven with warp threads (6A), whereas between each weft thread (5A) the pairs of warp threads (6B, 6C) of a single warp thread (6A) are intertwined with each other, reducing the distance between the two weft threads (5A) to almost zero. This type of leno weave creates spaces between the weft threads, making the fabric more open. The space between the wefts acts as a pivot point, creating a flexible fabric that easily conforms to the complex contours of the goods it stores. The relative effectiveness of the pivot point may be enhanced or reduced by altering the warp/warp and weft/fill yarn structures.

As shown in the schematic diagram of fig. 1, a leno bag (1) of the prior art has narrow strips of film strips as warp/warp and weft/weft yarns. Figure 1B shows an enlarged view of a conventional leno pocket fabric structure in which the weft/fill yarns and warp/warp yarns are made from strips of plastic film. The denier and width of the warp/warp and weft/fill yarns may be the same or different depending on the packaging requirements. This structure lacks flexibility (due to the sharpness or toughness of the belt edges) and less coverage.

Thus, the fabric of the present invention (see FIG. 2) has some of the texturizing yarns incorporated into the weave pattern, making the fabric softer than conventional fabrics. This critical aspect of the invention results in a bag that is less rugged with cargo than bags made from conventional woven fabrics made from stiff yarns.

There are a variety of patterns within the scope of the invention such that the weight of the bulked yarns (7) used in the fabric can be up to 100% by weight of the fabric gsm (grams per square meter) and/or the weight of the stiff yarns (8) used in the fabric can be up to 95% by weight of the fabric gsm (grams per square meter).

Depending on the type of yarn used to form the weft and warp yarn structures (5, 6), a variety of weave patterns are possible.

In a preferred embodiment of the invention (see fig. 2A), a bulked yarn (7) is used as weft/shute (5A) of the shute structure (5). In this embodiment, of the warp/warp yarns (6A) consisting of a pair of warp strands (6B, 6C), one is made of a bulky yarn (7) and the other is made of a hard yarn (8). Here, two warp strands (6B, 6C) are braided by being intertwined with each other, thereby forming a wrap loop (L). The weft (5A) passes through the loops (L) of the pair of twisted warp strands (6B, 6C).

Fig. 2B and 2C show some weave patterns in which the bulked yarns are part of the warp structure (6) of the fabric. Each warp yarn (6A) comprises two warp yarn strands (6B, 6C), one made of hard yarn (8) and the other made of bulked yarn (7). However, the weft yarn structure (5) may comprise fully hard yarns (8) (fig. 2B) or a combination of hard yarns (8) and bulk yarns (7) arranged in various arrangements (fig. 2C). For example, in the weft structure (5), the hard yarns (8) and the bulked yarns (7) may alternate, or there may be only the bulked yarns (7) or only the hard yarns (8), or any number of successively positioned hard yarns (8) followed by any number of bulked yarns (7).

Fig. 3A, 3B and 3C show various other weave patterns in which the warp yarn structure (6) of the fabric is formed entirely using the bulked yarns (7). However, the weft structure (5) may comprise completely hard yarns (8) or a combination of hard yarns (8) and bulky yarns (7) arranged in various arrangements. For example, in the weft structure (5), the hard yarns (8) and the bulky yarns (7) may alternate, or there may be only the bulky yarns (7) or only the hard yarns (8), or any number of successively positioned hard yarns (8) followed by any number of successively positioned bulky yarns (7).

Fig. 4A and 4B show various weave patterns in which the warp structure (6) of the fabric is made entirely of hard yarns (8). The weft yarn structure (5) can here be made entirely of bulk yarns (7) or be arranged with alternating bulk (7) and hard (8) yarns.

Fig. 5A and 5B show various weave patterns in which the warp structure (6) is made such that any single warp (6A) can be made from either a bulked yarn (7) or a stiff yarn (8). The warp threads (6A) are arranged in an alternating pattern of warp threads (6A) made entirely of bulky threads (7) and warp threads (6A) made entirely of hard threads (8). It is also possible to arrange a plurality of warp threads (6A) made entirely of bulked yarns (7) in succession before the introduction of warp threads (6A) made entirely of hard yarns (8). The weft structure (5) pattern combined with this warp structure (6) pattern comprises fully bulked yarns (7) or fully stiff yarns (8). Alternatively, the weft structure (5) may comprise alternating lines of bulked yarns (7) and hard yarns (8).

Fig. 6A, 6B and 6C show a variety of further weaving patterns in which the warp structure (6) is made such that at least one warp yarn (6A) can be made of a combination of a bulky yarn (7) and a hard yarn (8) -that is, either of the two warp strands (6B or 6C) is made of a bulky yarn (7) while the other strand (6C or 6B) is made of a hard yarn. The fabric may have any number of such warp threads arranged in succession or alternating with warp threads (6A) made entirely of hard yarns. The warp threads (6A) are arranged in such a way that the bulk threads (7) and the hard threads (8) alternate. The weft structure (5) pattern combined with this warp structure (6) pattern comprises fully bulked yarns (7) or fully stiff yarns (8). Alternatively, the weft structure (5) may comprise alternating lines of bulked yarns (7) and hard yarns (8).

Figures 7A, 7B and 7C show a number of further weaving patterns in which the warp structure (6) is made such that at least one warp yarn (6A) can be made of a combination of a bulky yarn (7) and a hard yarn (8) -that is, either of the two warp strands (6B or 6C) is made of a bulky yarn (7) while the other strand (6C or 6B) is made of a hard yarn. In this embodiment, the warp structure (6) further comprises warp threads (6A), wherein both warp strands (6B, 6C) are made of bulked yarns (7). The fabric may have warp threads from either of the two types arranged in succession or alternating with warp threads (6A) of the other type. The weft structure (5) pattern combined with this warp structure (6) pattern comprises fully bulked yarns (7) or fully stiff yarns (8). Alternatively, the weft structure (5) may comprise alternating lines of bulked yarns (7) and hard yarns (8).

The hard yarn (8) used in the leno fabric according to the invention can be any type of thin strip of film or monofilament yarn. The hard yarns may be fibrillated or folded or simply slit film tapes made of a polymeric material, preferably a polyolefin. Alternatively, the hard yarn may be made of a biodegradable material. The bulky yarn (7), due to its intrinsic structure, contributes to increase the softness of the fabric made of this yarn, and also to increase the friction with the adjacent yarns, which is essential for the structural robustness of the fabric. The unique combination of bulked yarns (7) and hard yarns (8) in the warp (6A) provides better stability and structural integrity to the overall material. The hard yarn (8) used in the present invention has a denier range of 50 to 1200 and a width of 0.5 mm to 12 mm.

Bulked yarns (7) are yarns processed to have a greater covering power or apparent volume than conventional yarns of the same base material of the same linear density and normal twist, these bulked yarns are commonly referred to as bulked continuous filament yarns (BCF). BCF yarns include any continuous filament yarn whose smooth, straight fibers are transferred from their closely packed parallel position by introducing some form of twist, crimp, looping or looping. Lofting imparts aesthetic properties to the filaments as spun yarns by changing surface properties and creating spaces between the fibers. The fiber fabric is more absorbent, more comfortable and has better bulkiness, covering ability and elasticity. These characteristics are very important for protecting the goods during storage/transport. They are more breathable and more moisture permeable. The static charge build-up is low. The bulked yarn does not peel or fall off.

In one aspect of the invention, the bulked yarn (7) may be made of biodegradable material or a combination thereof with rayon. The individual bulked yarn components will typically have a denier of about 100 to 2000, however, it is preferred to use a yarn component of 150 to 5000 denier.

Bulked yarns are classified into three categories: bulked or expanded yarns, stretch yarns, and textured yarns.

Bulked yarns formed from natural bulked fibers, such as rayon fibers that are hollow along some or all of their length, or yarns formed from fibers that cannot be tightly packed due to their cross-sectional shape, fiber arrangement, stiffness, elasticity, or natural crimp. A large number of products use bulked yarns, from carpets to undergarments, from sweaters to laces. However, their use in leno fabrics for the storage of perishable goods and other types of goods is not clear.

Stretch yarns are thermoplastic filaments or yarns with high latent elastic stretch (30-100%), fast coverage and high yarn twist. The bulk of the stretch yarn is moderate. Stretch yarn (nylon) is widely used for knitwear, silk stockings, tights, swimwear, sweaters, however, it is not known at present that these are used to make leno fabrics for cargo storage/transportation.

The bulking yarns can be used from two broad classes: i) continuous multifilament textured yarns and ii) staple fiber yarns (stable fiber spun yarns). Textured yarns are produced by conventional raw texturing or air texturing processes. The air texturing process uses compressed air to change the texture of the yarn by disrupting and looping the filaments that make up the bulk structure of the yarn. Air textured bulked yarns are typically made of low cost polypropylene, polyethylene, or polyester, among others.

Textured yarn is the generic term for any continuous filament yarn whose smooth, straight fibers are transferred from their closely packed parallel position by introducing some form of crimp, twist, looping or looping. Textured yarns may be made from filament fibers given some type of textured construction or staple fibers cut from filaments. Most textured yarns are made from filament fibers. Textured yarns can be uniform in shape and smooth in appearance, as can simple yarns, or they can be irregular, giving them some resemblance to complex yarn structures. Texturing imparts aesthetic properties to smooth filaments by the spun yarn by altering the surface properties and creating spaces between the fibers. This results in a fabric with better air permeability, greater moisture permeability, greater comfort and less static buildup.

Textured yarns are the generic term for conventional yarns having an apparent volume or volume significantly greater than a similar filament count, or for filaments that have been rendered more extensible by texturing the filaments by physical, chemical, or thermal treatment, or a combination of these methods. The deformation can result in permanent deformation, curling, looping, or wrinkling without disrupting substantial filament continuity. This improves the texture of the yarn. Texturing gives the yarn a soft and wool-like feel and increases the warmth and comfort of the fabric. The loops and curls trap (entrap) a large number of small air pockets. The filaments impede the flow of air and hold the fabric together. Especially in the case of leno-type fabrics for perishable goods storage, the softness of the fabric is very important to reduce damage to the goods during storage and/or transport.

The main purpose of the textured filament yarn is to create the desired lofty structure for the following reasons:

the voids in the structure give the material good insulating properties.

The voids in the structure change the density of the material, making it lightweight and covering.

The random surface of the yarn produces a diffuse light reflection, which in turn produces the desired matt appearance.

The sponge-like structure feels softer than the obliquely twisted flat yarn.

The crimped filament structure imparts a lower effective modulus of elasticity (elasticity) to the structure compared to flat yarns.

The man-made textured yarn is a fully drawn, fully oriented multifilament yarn having soft-fold, high bulk and cotton-like texture, as well as very high durability and retention properties. This is made by texturing a partially oriented yarn using a high speed texturing machine. The textured filament yarn may be a draw textured yarn or an air textured yarn. The yarn produced by air jet texturing is known as Air Textured Yarn (ATY). The air jet texturing process is a purely mechanical method of producing low-ductility bulked yarns using a cold air stream. ATY is very bulky, with permanent curls and loops. In an ATY, a rayon yarn may be combined with a natural fiber yarn.

The yarn can have a variety of effects including twisting, stretching and relaxing, softening using air jets, spike crimping, circular crimping, heated gear crimping and crimping using stuffer box crimping.

Another type of bulking yarn may be from staple fibers. Staple fibers are short in length, typically only a few inches long. They are twisted together to form longer strands. The two main types of staple fiber yarn are conventional ring spinning and friction spinning. Friction spinning is produced by a friction spinning process, such as Dref, which produces large diameter, bulky yarns.

The dimensional rigidity of the bag structure of the invention is provided by hard yarns (8) (see fig. 2A) which may be monofilaments, strips of film or folded strips of film or binder yarns or the like.

The bag fabric may use a conventional flat or circular loom designed for leno weaving.

The open mesh structure of the woven improved fabric obtained by the present disclosure herein may be further enhanced by the use of a variety of different yarns/fibers (geometries, types, cross-sections, and combinations thereof) and textile structures arranged in specific patterns or alternative ways. The modified layout of distinct yarn types directly contributes to the enhanced dimensional structure and mechanical properties.

Further, conventional leno fabrics made from plastic tapes show a dimensional deformation of about 4% to 12% during cyclic load testing, while the leno fabrics of the invention with a combination of bulked and hard yarns in the warp show negligible dimensional deformation, resulting in a more stable structure.

Some other aspects of the invention are now disclosed.

In one aspect, the hard and bulked yarns may be produced using rayon yarns. In another aspect, the bulked yarns or the stiff yarns or both are biodegradable. In another aspect of the invention, either yarn may contain pigments or additives or inorganic fillers or processing aids or Ultraviolet (UV) stabilizers.

The total weight of the leno fabric of the invention is less than 120 grams per square meter.

While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of preferred embodiments thereof. It must be appreciated that modifications and variations are possible in light of the above teachings without departing from the spirit and scope of the present invention. Accordingly, the scope of the present invention should be determined not by the illustrated embodiments, but by the appended claims and their legal equivalents.

Claims

1. An open mesh leno fabric comprising a warp structure (6) made of warp yarns (6A) and a weft structure (5) made of weft yarns (5A), the warp yarns (6A) consisting of two warp strands, a first warp strand (6B) and a second warp strand (6C), the two warp strands (6B, 6C) being woven to form loops (L), a single weft yarn (5A) passing through each of the loops (L), the fabric being characterized in that at least some of the warp (6A) and/or weft (5A) yarns comprise bulked yarns.

2. Open mesh leno fabric according to claim 1, wherein any one of the two warp strands (6B or 6C) is made of bulked yarn (7) and the other strand (6C or 6B) is made of hard yarn (8).

3. Open mesh leno fabric according to claim 2, wherein all weft threads (5A) are made of bulked yarns.

4. Open mesh leno fabric according to claim 2, wherein all weft threads (5A) are made of hard yarns.

5. Open mesh leno fabric according to claim 2, wherein some weft threads (5A) are made of bulked yarns and other weft threads (5A) are made of hard yarns.

6. Open mesh leno fabric according to claim 1, wherein both warp strands (6B or 6C) are made of bulked yarns (7).

7. Open mesh leno fabric according to claim 6, wherein all weft threads (5A) are made of bulked yarns (7).

8. Open mesh leno fabric according to claim 6, wherein all weft threads (5A) are made of hard yarns (8).

9. Open mesh leno fabric according to claim 6, wherein some weft threads (5A) are made of bulked yarns (7) and other weft threads (5A) are made of stiff yarns (8).

10. Open mesh leno fabric according to claim 1, wherein both warp strands (6B or 6C) are made of hard yarns (8).

11. Open mesh leno fabric according to claim 10, wherein all weft threads (5A) are made of bulked yarns (7).

12. Open mesh leno fabric according to claim 10, wherein some weft threads (5A) are made of bulked yarns (7) and other weft threads (5A) are made of stiff yarns (8).

13. Open mesh leno fabric according to claim 1, wherein at least one warp thread (6A) has two warp strands (6B and 6C) made of bulked yarns (7) and wherein at least one other warp thread (6A) has two warp strands (6B, 6C) made of hard yarns (8).

14. Open mesh leno fabric according to claim 13, wherein all weft threads (5A) are made of bulked yarns (7).

15. Open mesh leno fabric according to claim 13, wherein all weft threads (5A) are made of hard yarns (8).

16. Open mesh leno fabric according to claim 13, wherein some weft threads (5A) are made of bulked yarns (7) and other weft threads (5A) are made of stiff yarns (8).

17. Open mesh leno fabric according to claim 1, wherein at least one warp thread (6A) has one warp strand (6B or 6C) made of bulky yarn (7) and another warp strand (6C or 6B) made of hard yarn, and wherein at least one other warp thread (6A) has two warp strands (6B and 6C) made of hard yarn (8).

18. Open mesh leno fabric according to claim 17, wherein all weft threads (5A) are made of bulked yarns (7).

19. Open mesh leno fabric according to claim 17, wherein all weft threads (5A) are made of hard yarns (8).

20. Open mesh leno fabric according to claim 17, wherein some weft threads (5A) are made of bulked threads (7) and other weft threads (5A) are made of stiff threads (8).

21. Open mesh leno fabric according to claim 1, wherein at least one warp thread (6A) has one warp strand (6B or 6C) made of bulked yarn (7) and another warp strand (6C or 6B) made of hard yarn, and wherein at least one other warp thread (6A) has two warp strands (6B and 6C) made of bulked yarn (7).

22. Open mesh leno fabric according to claim 21, wherein all weft threads (5A) are made of bulked yarns (7).

23. Open mesh leno fabric according to claim 17, wherein all weft threads (5A) are made of hard yarns (8).

24. Open mesh leno fabric according to claim 17, wherein some weft threads (5A) are made of bulked threads (7) and other weft threads (5A) are made of stiff threads (8).

25. The open mesh leno fabric according to claims 1 to 24, wherein the bulked yarns are made of one type comprising bulked yarns, stretch yarns or textured yarns or any combination thereof.

26. Open mesh leno fabric according to claim 25, wherein the bulked yarns (7) are selected from the group comprising continuous multifilament textured yarns and staple spun yarns.

27. An open mesh leno fabric according to claim 25, wherein the denier of the bulked yarns (7) is between 150 and 3000.

28. The open mesh leno fabric of claim 25 wherein the texturized yarn is obtained by any one of twisting, stretching and relaxing, softening using air jets, spike crimping, circular crimping, heated gear crimping and crimping using stuffer box crimping.

29. An open mesh leno fabric according to claim 25, wherein the hard yarn (8) used in the invention has a denier of 50 to 1200 and has a width of between 0.5 mm and 12 mm.

30. The open mesh leno fabric according to claim 26 wherein the staple fiber spun yarn is ring spun or friction spun.

31. An open mesh leno fabric according to any one of claims 1 to 30, wherein the bulky yarn (7) and/or the hard yarn (8) is biodegradable.

32. The open mesh leno fabric according to any one of claims 1 to 31, wherein the bulky yarn (7) and/or the hard yarn (8) comprises any component from the group of components consisting of colour pigments, additives, inorganic fillers, processing aids and UV stabilizers.

33. A bag made of an open mesh leno fabric, characterized in that the fabric comprises a warp structure (6) made of warp threads (6A) and a weft structure (5) made of weft threads (5A), the warp threads (6A) consisting of two warp strands, a first warp strand (6B) and a second warp strand (6C), the two warp strands (6B, 6C) being woven to form loops (L), a single weft thread (5A) passing through each of the loops (L), characterized in that at least some of the warp threads (6A) and/or weft threads (5A) comprise bulked yarns.

34. A method of manufacturing a leno fabric, characterized in that the method comprises the steps of:

-providing a warp structure (6) made of warp threads (6A) and a weft structure (5) made of weft threads (5A), said warp threads (6A) comprising two warp strands, a first warp strand (6B) and a second warp strand (6C),

-weaving the two warp strands (6B, 6C) to form loops (L), a single weft thread (5A) passing through each loop (L),

characterized in that at least some of the warp threads (6A) and/or weft threads (5A) comprise a bulky yarn.