WO2020263204A1

WO2020263204A1 - A cord and a cord production method

Info

Publication number: WO2020263204A1
Application number: PCT/TR2020/050404
Authority: WO
Inventors: Yucel Ayyildiz; Ezgi TAMAN ONEN
Original assignee: Kordsa Teknik Tekstil A.S.
Priority date: 2019-06-28
Filing date: 2020-05-08
Publication date: 2020-12-30
Also published as: TR201909662A1; EP3990293A1

Abstract

A cord which is suitable for use in tires and a production method for the said cord are developed with the present invention. The said cord comprises at least one hollow fiber and/or at least one fabric (1) woven from the said at least one hollow fiber, and at least one coating (2) which is coated on the said at least one fiber and/or the said woven fabric (1). The said production method comprises the steps of producing at least one hollow fiber; coating the produced fiber at least one coating (2).

Description

A CORD AND A CORD PRODUCTION METHOD

Technical Field

The present invention, relates to a cord which is suitable for use especially in pneumatic tires specifically for sound absorption and a production method for the said cord.

Background of the Invention

Especially in land and air vehicles, tires that allow the vehicle to move on a ground are used. It is preferred that said tires have a damping structure so that driving comfort is achieved on different surfaces. Pneumatic tires are used in order to provide said damping in conventional applications. In the said pneumatic tires, air with a certain pressure is compressed into the tire. Damping process is achieved thanks to the tire being manufactured from an elastic material and the air inside the tire having a compressible structure.

Noises may occur due to interaction between the tire and the road, especially when pneumatic tires are used. There are basically two sources of this noise. One of these sources is the sound waves that are caused by friction and vibration between the tread of the tire and the road and that move along the tire. The second source of the noise is the sound waves generated as a result of the vibration created by air compressed in gaps on the tread area of the tire. The noise generated in the said sources can disturb the drivers inside the vehicle, as well as disturb the people around the vehicle.

In the state of the art, there are applications such as using materials which can absorb the sound wave to prevent tire noise and using materials for reflection of the sound wave. United States patent document no US7735532B2, an application known in the state of the art, discloses providing sound absorption by using a foam material in the inner part of the tire. The foam material disclosed here has a structure that can absorb sound wave, and enables to prevent the noise. However, the foam material used in this document has a relatively heavy structure, thereby increasing the weight of the tire. Increase in the tire weight also decreases the energy efficiency of the vehicle in which the tire is used, which is not preferred.

United States patent document no US6422655B 1, an application known in the state of the art, discloses a noise absorber for pneumatic tires. In the said document, there is a strip attached to the rim of the tire and flexible fibers extending in form of protrusion over the said strip. However, this structure also increases the weight of the tire and noise can be generated due to the movement of the fiber at low speeds since the flexible fibers are attached to the strip from one side.

Summary of the Invention

A cord which is suitable for use in tires and a production method for the cord are developed with the present invention. The said cord comprises at least one hollow fiber and/or at least one fabric woven from the said at least one hollow fiber, and at least one coating which is coated on the said at least one fiber and/or the said woven fabric. The said production method comprises the steps of producing at least one hollow fiber; coating the produced fiber at least one coating.

In the cord developed with the present invention, sound waves are enabled to be absorbed by the said hollow structure by using the hollow fiber. The hollow fiber structure mentioned herein also ensures that the cord, which is added as a coating to at least one area of the tire or used as a layer in the tire, has a light structure Therefore, the noise is prevented without increasing the weight of the tire. Summary of the Invention

The objective of the present invention is to provide a cord which is suitable for use in pneumatic tires and enables to reduce the noise of the tire, and a production method for the said cord.

Another objective of the present invention is to provide a cord which does not increase the weight of the tire in which it is used, and a production method for the said tire.

A further objective of the present invention is to provide a cord which is durable, reliable and easy to produce, and a production method for the said tire.

Description of the Figures

The exemplary embodiments of the cord developed with the present invention are illustrated in the accompanying figures, in which

Figure 1 is a perspective view of the cord.

Figure 2 is a top view of a fabric structure used in the cord.

Figures 3a-3d are cross-sectional views of hollow fiber used in the cord in different applications.

Figure 4 is the frequency/sound absorption coefficient graphic of a cord developed with the present invention at different speeds.

Figure 5 is the frequency/sound absorption coefficient graphic of a cord comprising a conventional fiber at different speeds.

The components given in the figures are individually numbered where the numbers refer to the following.

Fabric (1) Weft yarn (la)

Warp yarn (lb)

Coating (2)

Description of the Invention

Pneumatic tires are preferred in many land and air vehicles due to their durable and flexible structures. However, in such tires, noise caused by friction and vibration between the tread of the tire and the road, and noise caused by the vibration generated due to air compressed in the gaps of the tread area of the tire may occur. These noises that are generated may disturb people both inside and outside the vehicle. For this reason, a cord which is suitable for use in pneumatic tires and enables to reduce the noise of the tire, and a production method for the said cord are provided with the present invention.

The cord developed with the present invention and the exemplary appearances of which are given in Figures 1 and 2 comprises at least one hollow fiber (for example in form of a pipe) and at least one coating (2) coated on the said fiber. Here, the said cord preferably comprises at least one fabric (1) comprising the said hollow fiber as least one weft yam (la) and/or at least one warp yarn (lb). The coating (2) mentioned in this embodiment can be coated on the weft yarns (la) and/or warp yams (lb) in form of hollow fiber, as well as it can be coated on the whole fabric (1).

The cord production method developed with the present invention comprises the steps of producing at least one hollow fiber preferably with extmsion method; coating the produced fiber at least one coating (2). The method mentioned in a preferred embodiment, wherein the said fiber is used as at least one weft yam (la) and/or at least one warp yam (lb) of at least one fabric (1), comprises the step of weaving at least one fiber (1) comprising the hollow fiber as at least one weft yarn (la) and/or at least one warp yam (lb). The said weaving process may be performed before the step of coating the produced fiber with at least one coating (2) (in other words the coating process can be directly performed on the woven fabric (2)), as well as it can also be performed after the step of coating the produced fiber with at least one coating (2) (in other words the coated fibers can be woven by performing coating on the hollow fibers). Here, a resorcinol formaldehyde latex (RFL) solution is preferably used in the step of coating said produced fiber with at least one coating (2).

In a preferred embodiment of the invention, the said fabric (1) is a structure comprising leno weaving as shown in figure 2. Leno weaving process is performed in step of weaving at least one fabric (1) comprising the said hollow fiber present in the said production method mentioned in this embodiment as at least one weft yarn (la) and/or at least one warp yarn (lb). The use of leno weaving in the fabric (1) both prevents the cords coming out of the edges of the strip and also increases the sound absorption capacity. In addition to this, different types of weavings as plain weaving can also be used in the said fabric (1).

In another preferred embodiment of the invention, the said production method comprises the step of applying twisting process to weft yams (la) and/or warp yarns (lb) before the step of weaving at least one fabric (1) comprising the said hollow fiber as at least one weft yam (la) and/or at least one warp yarn (lb). Here, twisting can be applied on the said weft yarns (la) and/or warp yarns (lb) in lxl, 1x2, 1x3 styles.

In another preferred embodiment of the invention, the hollow fiber is in form of a cylinder, a cross-sectional view of which is given in Figure 3a. In an alternative embodiment, the cross sectional view of the hollow fiber may be in the form of a strip as shown in figure 3b, in a three-lobe form as shown in figure 3c, or in a hexagonal form as shown in figure 3d. The coating (2) mentioned in another preferred embodiment of the invention comprises polyurethane, epoxy, polyacrylate, silane, polyamide, resorcinol, formaldehyde, latex based materials or a mixture thereof. Here, latex based material may be styrene butadiene rubber (SBR), vinylpyridine styrene butadiene rubber (VP-SBR), nitrile butadiene rubber (NBR), natural rubber or chloropene rubber (CR).

In a different preferred embodiment of the invention, the said weft yarns (la) and/or warp yarns (lb) comprise polyamide, polyethylene terephthalate, polypropylene, polyketone, polyethylene naphthalate or a combination thereof. Here, at least one of the weft yams (la) and/or warp yams (lb) may comprise cotton or rayon. In other words, cotton-based weft yams (la) and/or warp yams (lb) and polymer-based weft yarns (la) and/or warp yarns (lb) can be used in said fabric (1) together. Here, the linear density of said weft yarns (la) and/or warp yarns (lb) is preferably in the range of 50-2000 dtex, more specifically in the range of 100-400 dtex.

In another preferred embodiment of the invention, the said method comprises the step of at least one cutting step after the step of coating the produced fiber (or the fabric comprising the fiber) with at least one coating (2). Here, the obtained cord is cut in desired shapes and sizes according to the field of use.

In another preferred embodiment of the invention, the cross-sectional ratio of the gap to the fiber material in the cross sections of the hollow fiber is in the range of 5 to 30%. Therefore, sound insulation is achieved with the use of optimum material.

Furthermore, a tire comprising the said cord is also developed with the present invention. In a preferred embodiment, the cord developed with the present invention is present as a top layer (in other words such as coating or adhesive) in a bead fabric area, below a tread area, on an inner layer, between the cap ply fabric, below sidewall of the tire and/or rim connection area of a tire. The cord mentioned in this embodiment can be adhered to the said areas via at least one adhesive member. In an alternative embodiment, the tire may also comprise the said cord as a layer (an internal part) on the cap ply area. Here, the tire is provided to absorb sound waves by means of comprising the hollow fiber. Therefore, it is ensured that the disturbing noise generated in the tire is eliminated.

A test was carried out to determine the sound absorption property of the cord developed with the present invention at different frequencies. In the test, the changes of sound absorption coefficients depending on the frequency at different rotational speeds of a hollow fiber according to the present invention and a cord comprising a conventional (non-hollow) fiber are given in figure 4 and figure 5, respectively. When the said graphics are examined, it is seen that the sound absorption coefficient especially in high frequencies is higher in the cord comprising the hollow fiber (developed with the present invention) relative to a cord comprising the conventional fiber. According to the said graphics, in the cord developed with the present invention, it is seen that the sound absorption coefficient also increases especially for high frequencies, as the rotation speed of a tire comprising the cord increases. In a cord comprising conventional fiber, increasing the rotation speed of the tire on which the cord is used hardly changes the sound absorption coefficient.

In the cord developed with the present invention, sound waves are enabled to be absorbed by the said hollow structure by using the hollow fiber. The hollow fiber structure mentioned herein also ensures that the cord, which is added as a coating to at least one area of the tire or used as a layer in the tire, has a light structure Therefore, the noise is prevented without increasing the weight of the tire.

Claims

1. A cord suitable for use in a tire, characterized in that it comprises at least one hollow fiber and/or at least one fabric (1) woven from the said at least one hollow fiber, and at least one coating (2) which is coated on the said at least one fiber and/or the said woven fabric (1).

2. A cord according to claim 1, characterized in that the said fabric (1) comprises the hollow fiber as at least one weft yarn (la) and/or at least one warp yam (lb).

3. A cord according to claim 2, characterized in that the said fabric (1) has a stmcture comprising leno weaving.

4. A cord according to claim 2, characterized in that the said fabric (1) has a structure comprising plain weaving.

5. A cord according to any one of the claims 2 to 4, characterized in that the said weft yarns (la) comprise polyamide, polyethylene terephthalate, polypropylene, polyketone, polyethylene naphthalate or a combination thereof.

6. A cord according to any one of the claims 2 to 5, characterized in that the said warp yams (lb) comprise polyamide, polyethylene terephthalate, polypropylene, polyketone, polyethylene naphthalate or a combination thereof.

7. A cord according to claim 5 or 6, characterized in that at least one of the weft yarns (la) and/or warp yams (lb) comprises cotton or rayon.

8. A cord according to any one of the claims 2 to 7, characterized in that the linear density of the said weft yarns (la) and/or warp yams (lb) is in range of 50-2000 dtex.

9. A cord according to claim 8, characterized in that the linear density of the said weft yarns (la) and/or warp yarns (lb) is in range of 100-400 dtex.

10. A cord according to any one of the preceding claims, characterized in that the hollow fiber has a cylindrical form.

11. A cord according to any one of the claims 1 to 9, characterized in that the hollow fiber is in form of a strip.

12. A cord according to any one of the claims 1 to 9, characterized in that the cross-section of the hollow fiber is in three-lobe form.

13. A cord according to any one of the claims 1 to 9, characterized in that the cross-section of the hollow fiber is in hexagon form.

14. A cord according to any one of the claims 2 to 13, characterized in that the said weft yarns (la) and/or warp yarns (lb) have a twisted structure.

15. A cord according to claim 14, characterized in that the twisting style of the said weft yarns (la) and/or warp yarns (lb) is lxl, 1x2 or 1x3.

16. A cord according to any one of the preceding claims, characterized in that the said coating (2) comprises polyurethane, epoxy, polyacrylate, silane, polyamide, resorcinol, formaldehyde, latex based materials or a mixture thereof.

17. A cord according to claim 16, characterized in that the said latex based material is styrene butadiene rubber, vinylpyridine styrene butadiene rubber, nitrile butadiene rubber, natural rubber or chloropene rubber.

18. A cord according to any one of the preceding claims, characterized in that areal ratio of the space to the fiber material in the cross sections of hollow fiber is in the range of 5% to 30%.

19. A tire characterized in that it comprises a cord according to any one of the preceding claims.

20. A tire according to claim 19, characterized in that the said cord is present as an upper layer in a bead fabric area, below a tread area, on an inner layer, between cap ply fabric, below tire sidewall area and/or rim connection area.

21. A tire according to claim 19 or 20, characterized in that the cord is present in a cap ply area as at least one layer.

22. A production method for a cord or fabric or strip which comprises at least one hollow fiber and at least one coating (2) coated on the said fiber and is suitable for use in a tire, characterized in that it comprises the steps of

- producing at least one hollow fiber;

- coating the produced fiber with at least one coating (2).

23. A method according to claim 22, characterized in that resorcinol formaldehyde latex solution is used in step of coating the produced fiber with at least one coating (2).

24. A method according to claim 22 or 23, characterized in that it comprises the step of weaving at least one fabric (1) comprising the said hollow fiber as at least one weft yarn (la) and/or at least one warp yarn (lb).

25. A method according to claim 24, characterized in that the step of weaving at least one fabric (1) comprising the said hollow fiber as at least one weft yarn (la) and/or at least one warp yarn (lb) is performed before the step of coating the produced fiber with at least one coating (2).

26. A method according to claim 24, characterized in that the step of weaving at least one fabric (1) comprising the said hollow fiber as at least one weft yarn (la) and/or at least one warp yam (lb) is performed after the step of coating the produced fiber with at least one coating (2).

27. A method according to any one of the claims 24 to 26, characterized in that leno weaving process is performed in the step of weaving at least one fabric (1) comprising the said hollow fiber as at least one weft yam (la) and/or at least one warp yarn (lb).

28. A method according to any one of the claims 24 to 26, characterized in that plain weaving process is performed in the step of weaving at least one fabric (1) comprising the said hollow fiber as at least one weft yam (la) and/or at least one warp yarn (lb).

29. A method according to any one of the claims 24 to 27, characterized in that it comprises the step of applying twisting process to weft yarns (la) and/or warp yarns (lb) before the step of weaving at least one fabric (1) comprising the said hollow fiber as at least one weft yarn (la) and/or at least one warp yarn (lb).

30. A method according to claim 29, characterized in that the twisting styles are lxl, 1x2 or 1x3 in the said twisting process.

31. A method according to any one of the claims 22 to 30, characterized in that it comprises at least one cutting step after the step of coating the produced fiber with at least one coating (2).