Yarn for technical fabrics and method for manufacturing the same

Abstract

 The present invention relates to a yarn (1) comprising an inner glass filament (2) covered by a first thread (4) wound in a first winding direction, on which a second thread (6) is wound, which is wound in an opposite direction to the first thread. The wound yarn is twisted on a third thread (8a) and/or a fourth thread (8b), which are twisted in an opposite twisting direction to the second thread.
The yarn is suitable for making technical fabrics having high cut strength and abrasion resistance.

Description

[0001] The present invention relates to a yarn for protective fabrics, i.e. a yarn having high wear resistance mechanical properties, usually called a "technical" yarn in the field, which is suitable for making fabrics for manufacturing work gloves and other safety garments.

[0002] A number of technical yarn types are available.

[0003] US 4.777.789, for example, illustrates a yarn consisting of an inner core made of a monofilament or multifilament, such as of glassfiber, on which an inner thread is wound, for example made of stainless steel. The core and the inner thread are covered by a first thread wound in a first winding direction, which forms a first covering layer; the first covering layer is covered by a second thread wound in a second winding direction, which forms a second covering layer. The first wound thread and the second wound thread are made of, for example, aramide resin.

[0004] Some examples of yarns are disclosed in US 2005/086924, US 6,467,251, US 5,845,476, US 6,279,305, US 6,779,330 e US 2004/148921.

[0005] Moreover, US 4,202,382, US 3,726,078, EP-A2-0125505, US 4,470,251, US 4,158,946, US 3,336,744 further illustrate other types of yarns.

[0006] The object of the present invention is to provide a novel type of yarn, having high mechanical characteristics, even more suitable to make technical fabrics as compared with known yarns, especially for protective garments.

[0007] Particularly, the yarn being the object of the present invention exhibits a high cut strength and a high workability during garment weaving.

[0008] This object is achieved by a yarn in accordance with claim 1, which can be obtained by means of the fabrication methods in accordance with claims 25 and 26.

[0009] The characteristics and advantages of the yarn and method according to the present invention will be apparent from the description given below, which is given by way of a non-limiting example, in accordance with the figures below, in which:

[0010] Fig. 1 to 5 illustrate variant embodiments of a yarn according to the present invention; and

[0011] Fig. 6 illustrates a garment made by means of the yarn of the present invention, for example, a glove.

[0012] With reference to Fig. 1, with 1 has been generally designated a yarn comprising a core consisting of a continuous filament 2.

[0013] The continuous filament 2 consists of a monofilament, such as made of glass or an elastic material, for example Lycra®, extending along a filament axis X.

[0014] For example, the filament 2 has linear density of 110 dtex.

[0015] The yarn 1 further comprises a first thread 4, wound around the continuous filament 2, such as to provide a first covering of the latter, in contact with the outer surface of the filament.

[0016] The first thread 4 is wound around the filament 2 in a first winding direction and with an inclination relative to the filament axis X. For example, the first thread is wound on the filament such as to obtain 500 coils along one linear meter of filament.

[0017] Preferably, the first thread is a polyester or polyamide continuous filament.

[0018] Preferably, the first thread 4 is further worked on the surface thereof such as to have a high roughness.

[0019] For example, the first thread has a linear density ranging between 50 and 200 dtex, preferably of 110 dtex.

[0020] The first cover provides a continuous layer, which covers the filament 2, since the coils of the first thread 4 wound on the filament 2 are axially tangential relative to each other, such as to avoid leaving gaps therebetween, from which the underlying filament 2 may appear. In other words, the first thread forms a closed coiling.

[0021] The yarn 1 further comprises a second thread 6 wound around the first cover, such as to provide a second cover thereon.

[0022] The second thread 6 is wound around the first cover in a second winding direction, opposite the first one. For example, the second thread has an inclination relative to the filament axis X opposite the first thread inclination.

[0023] For example, the second thread is wound on the first cover such as to obtain 500 coils along a linear meter.

[0024] Preferably, the second thread is a polyester or polyamide continuous filament.

[0025] Preferably, the second thread 6 is further worked on the surface thereof such as to have a high roughness.

[0026] For example, the second thread has a linear density ranging between 50 and 200 dtex, preferably of 110 dtex.

[0027] Preferably, the linear density of the second thread is equal to the linear density of the first thread.

[0028] The second cover provides a continuous layer that covers the first cover because the coils of the second thread are axially tangential to each other, such as to avoid leaving gaps therebetween, from which the first underlying cover may appear.

[0029] Furthermore, the yarn 1 comprises a third thread 8, wound on the second cover.

[0030] The third thread 8 does not provide a continuous covering on the second cover, since the twisting is carried out such that a gap is left between the coils, in order to make the second underlying cover visible and accessible. In other words, the third thread forms an open coiling, as it is wound on the covered thread.

[0031] For example, the third thread has a twisting with a twist linear density between 100 and 200 per linear meter, preferably equal to 170 twists per linear meter.

[0032] Preferably, the third thread 8 is wound around the second cover according to a twisting direction opposite that of the second thread.

[0033] Preferably, the third thread is a high-tenacity yarn, for example with a tenacity ranging between 40 and 120 cN/tex, preferably of 70 cN/tex.

[0034] Preferably, the third thread is made of a high-tenacity primary organic matrix (generally having tenacity values of 1.5 to 3.5 N/tex), coupled to further fibers.

[0035] For example, the third thread is made as a yarn, for example by means of ring spinning, from discontinuous polyethylene fibers and polyamide fibers, for example at the same or different weight ratio.

[0036] For example, the third thread is made as a yarn from discontinuous Dyneema® fibers and polyamide.

[0037] Fig. 2 illustrates a further variant embodiment of the yarn according to the present invention.

[0038] In Fig. 2, and following figures, the same numerals in Fig. 1 are used to designate similar parts.

[0039] According to the variant embodiment illustrated herein, the yarn 1 comprises a multifilament core, such as consisting of two filaments 2a, 2b, parallel to each other.

[0040] Similarly to the variant embodiment in Fig. 1, the core is covered by the first cover being the first thread 4, by the second cover formed being the second thread 6, and twisted along with the third thread 8.

[0041] Fig. 3 illustrates a further embodiment of the yarn according to the present invention.

[0042] According to the variant embodiment illustrated herein, the yarn 1 comprises a monofilament core, consisting of an individual filament 2, covered by the first cover being the first thread 4, which is, in turn, covered by the second cover being the second thread 6, on which a third thread 8a and a fourth thread 8b are twisted.

[0043] The fourth thread 8b has structural characteristics similar to those of third thread 8a.

[0044] For example, the third thread 8a has a first twisting direction, such as opposite that of second thread 6, and the fourth thread 8b has a second twisting direction, equal to the first twisting direction.

[0045] It will be understood that, in the embodiments described above, the first cover is in direct contact with the yarn core; in other words, there are no intermediate threads between the glassfiber core and the first cover.

[0046] Fig. 4 illustrates a further embodiment of the yarn according to the present invention.

[0047] According to the embodiment illustrated herein, the yarn comprises a multifilament core, for example consisting of two continuous filaments 2a, 2b parallel to each other, on which a coupling thread 10 is twisted.

[0048] On the coupling thread 10 is wound the first thread 4 of the first cover, on which is wound the second thread 6 of the second cover, on which are twisted the third thread 8a and the fourth thread 8b, or, in a further embodiment, an individual third thread 8.

[0049] Fig. 5 illustrates a further embodiment of the yarn according to the present invention.

[0050] According to the embodiment illustrated herein, the yarn comprises a monofilament core, consisting of an individual filament 2, on which the coupling thread 10 is twisted.

[0051] On the coupling thread 10 is wound the first thread 4 of the first cover, on which is wound the second thread 6 of the second cover, on which is twisted the third thread 8, or, in a still further embodiment, the third thread 8a and the fourth thread 8b.

[0052] According to other embodiments, the third and/or the fourth thread, according to embodiments here above, comprises, besides a stiff yarn, for example from discontinuous polyethylene fibers and polyamide fibers, also a flexible yarn, for example a synthetic polyurethane fiber, for example lycra®.

[0053] For example, the third thread is made as a yarn from discontinuous Dyneema® fibers and polyamide.

[0054] The yarn according to the present invention is particularly suitable to make technical fabrics for protective garments, such as a glove 100.

[0055] The yarn according to the present invention can be fabricated according to a fabrication method comprising the steps of:

[0056] - arranging at least one glass continuous filament;

[0057] - feeding the continuous filament along a filament axis (X);

[0058] - wounding a first thread around the continuous filament being fed, thus providing a first cover overlapping the continuous filament with closed coiling, said winding being carried out according to a first winding direction;

[0059] - winding a second thread around the first cover already wound around the continuous filament, thus providing a second cover overlapping the first cover with closed coiling, said second cover having a second winding direction, opposite the first one;

[0060] - twisting a third thread (8) around the second cover already wound on the first cover, with open coiling in a twisting direction opposite that of second cover.

[0061] Particularly, the yarn according to the variant embodiment in Fig. 3 can be fabricated according to a fabrication method comprising the steps of:

[0062] - arranging at least one continuous filament;

[0063] - feeding the continuous filament along a filament axis X;

[0064] - winding a first thread around the continuous filament being fed, thus providing a first cover overlapping the continuous filament with closed coiling, said winding being provided according to a first winding direction;

[0065] - winding a second thread around the first cover already wound around the continuous filament, thus providing a second cover overlapping the first cover with closed coiling, said second cover having a second winding direction, opposite the first one;

[0066] - feeding the covered thread along with a third thread and a fourth thread;

[0067] - twisting the covered thread along with the third thread and the fourth thread, such that the third thread and fourth thread form an open coiling in the twisting direction opposite that of second cover.

[0068] It has been innovatively found how the yarn according to the present invention has excellent mechanical characteristics and a high workability for fabricating technical fabrics.

[0069] Particularly, it has been found how the third thread overlapping with open coiling the second cover provides the yarn with a high cut strength, without depriving the fabric of the softness required to make a comfortable garment.

[0070] It is believed that the increase in the cut strength is due to the holding action applied by the third thread on the coils of the second cover.

[0071] In other words, when a cutting body cuts the fabric made of the yarn according to the present invention, this cut presumably causes a local rupture of the second cover, which, however, does not flake off, due to the holding action applied by the third thread wound thereon.

[0072] In confirmation of this unexpected result, laboratory tests have been carried out, and particularly those tests pursuant to rule EN 388/03 (2003 ed.), which assigns level 5 to a fabric resisting to shear after twenty test cycles (Chapt. 6.2 of the rule) and level 4 to a fabric resisting to abrasion after eight thousand cycles (Chapt. 6.1 of the rule).

[0073] The fabric made of the yarn of the present invention has achieved level 5 cut resistance, and level 4 abrasion resistance.

[0074] According to a still further advantageous aspect, contrary to present knowledge, the provision of a third thread twisted on the second cover increases the fabric softness.

[0075] It is believed that this advantageous and unexpected effect is due to the fact that the third thread provides such a relief that, when the yarns are mutually engaged within the weft of a fabric, these are rested on each other at this relief. This increases the tendency of the yarn to flexibility and thus the fabric softness.

[0076] In other words, it is believed that this advantageous and unexpected effect is due to a reduced contact surface between the weft yarns of a fabric, which is due to the provision of the third externally-twisted thread.

[0077] Advantageously, furthermore, the provision of two threads twisted to the covered thread, in the same twisting direction, provides the fabric with a particular cut strength and abrasion resistance, while maintaining the fabric softness.

[0078] To opposite twisting directions, in fact, would correspond an undesired stiffening of the fabric.

[0079] According to a further advantageous aspect, the provision of the first and second covers provides the yarn with the desired strength for high-performing technical fabrics, while, by suitably selecting the materials, the fabric is sufficiently soft to provide a comfortable garment, or the mechanical properties can be changed as desired.

[0080] Advantageously, furthermore, the first and/or second threads have a surface roughness suitable to create a good grip of the first cover to the glass filament and/or the second cover to the first cover.

[0081] It is understood that those skilled in the art may carry out variations and modifications to the yarn and method described above, which are however all contemplated within the scope of protection as defined in the following claims.

Claims

1. A yarn (1) comprising:

- a core comprising at least one continuous filament (2) extending along a filament axis (X);

- a first thread (4) wound around the filament (2) along said filament axis (X) thus forming a first closed-coiling cover, said first thread being wound in a first winding direction;

- a second thread (6) wound about the first cover along said filament axis forming a second closed-coiling cover, said second thread being wound in a winding direction opposite the winding direction of the first thread;

- a third thread (8) wound around the second cover along the filament axis, twisted with an open coiling.

2. A yarn according to claim 1, wherein the third thread is wound such that the coils are axially spaced from each other, thus providing said open coiling.

3. A yarn according to claim 2, wherein the third thread is a high-tenacity yarn, i.e. having a tenacity ranging between 40 and 120 cN/tex, preferably of 70 cN/tex.

4. A yarn according to claim 3, wherein the third thread (8) is a polyethylene and polyamide discontinuous fiber yarn.

5. A yarn according to claim 4, wherein the third thread is a polyethylene and polyamide discontinuous fiber yarn at either the same or different weight ratio.

6. A yarn according to any preceding claim, wherein the third thread (8) is twisted in a twisting direction opposite the winding direction of the second thread (6).

7. A yarn according to any preceding claim, further comprising a fourth thread, twisted with an open coiling on the third thread.

8. A yarn according to claim 7, wherein the fourth thread has the same twisting direction of the third thread.

9. A yarn according to claim 7 or 8, wherein the fourth thread is a high-tenacity yarn.

10. A yarn according to any preceding claim, wherein the coils of the first and second covers are axially in contact with each other, thus providing said closed coiling.

11. A yarn according to any preceding claim, wherein the first thread is a polyester or polyamide continuous filament.

12. A yarn according to any preceding claim, wherein the second thread is a polyester or polyamide continuous filament.

13. A yarn according to any preceding claim, wherein the first thread has a linear density of 50 to 200 dtex.

14. A yarn according to claim 13, wherein the first thread has a linear density of 110 dtex.

15. A yarn according to any preceding claim, wherein the second thread has a linear density of 50 to 200 dtex.

16. A yarn according to claim 15, wherein the second thread has a linear density of 110 dtex.

17. A yarn according to any preceding claim, wherein the filament (2) is made of glass.

18. A yarn according to any claim 1 to 16, wherein the filament (2) is made of elastic material, such as Lycra®.

19. A yarn according to any preceding claim, wherein the filament has a linear density of 100 to 120 dtex.

20. A yarn according to claim 19, wherein the filament (2) has a linear density of 110 dtex.

21. A yarn according to any preceding claim, wherein the core comprises two parallel continuous filaments (2a, 2b).

22. A yarn according to any preceding claim, wherein the core comprises a coupling thread (10) wound with an open coiling, arranged between the filament and the first cover.

23. A fabric comprising a yarn made in accordance with any preceding claim.

24. A garment comprising a fabric according to claim 23.

25. A method for fabricating a yarn comprising the steps of:

- arranging at least one continuous filament (2);

- feeding the continuous filament along a filament axis (X);

- wounding a first thread (4) around the continuous filament being fed, thus providing a first cover overlapping the continuous filament with closed coiling, said winding being carried out according to a first winding direction;

- winding a second thread (6) around the first cover already wound around the continuous filament, thus providing a second cover overlapped to the first cover with closed coiling, said second cover having a second winding direction, opposite the first one;

- twisting a third thread (8) around the second cover already wound on the first cover, with open coiling in a twisting direction opposite that of second thread (6).

26. A method for fabricating a yarn comprising the steps of:

- arranging at least one continuous filament;

- feeding the continuous filament along a filament axis (X);

- winding a first thread around the continuous filament being fed, thus providing a first cover overlapping the continuous filament with closed coiling, said winding being provided according to a first winding direction;

- winding a second thread around the first cover already wound around the continuous filament, thus providing a second cover overlapping the first cover with closed coiling, said second cover having a second winding direction, opposite the first one;

- feeding the covered thread along with a third thread and a fourth thread;

twisting the covered thread along with the third thread and the fourth thread, such that the third thread and fourth thread form an open coiling in the twisting direction opposite that of second cover.

27. A yarn according to any one of claims 1 - 22, wherein the third and/or the fourth thread comprises, besides a stiff yarn, for example from discontinuous polyethylene fibers and polyamide fibers, also a flexible yarn, for example a synthetic polyurethane fiber.

Drawing