The present invention relates to a hybrid fabric, and a method to provide such a hybrid fabric. The invention further relates to the use of the hybrid fabric in a carcass of a tire.
JP-A-2010 255141 disclosed a tire cord fabric, which includes tire cords, each formed of synthetic fiber or pulp type fibers arranged as warp yarns. Wefts comprising polyethylene fibers or polypropylene fibers are alternatively interwoven into the warp yarns. Gaps with predetermined size are formed between warp yarns in groups of 5 to 20 yarns.
On one hand, the defined gaps between groups of predetermined number of tire cords function as cutting margins in order to provide joint-less bands after rubber calendaring process. On the other hand, if all the warp yarns are arranged at equal intervals with a predetermined warp density, a dispersion risk could arise during rubber calendering process, thus the variation in number of tire cords in the one joint-less band will come out. Besides, the uniformity of the intervals is lost at the same time. Even though arranged gaps of the warp yarn groups can minimize the dispersion risk and keep the number of the tire cords contained in one joint-less band sustained, it still can not prevent uniformity failures of final reinforced composite.
Such a tire cord fabric was used as reinforcement of a breaker or belt layer in a tire but not as a carcass of a tire.
It is an object of the invention to provide an improved fabric wherein the drawback of the above stated prior art is obviated.
It is also an object of the present invention to provide a new type of a hybrid fabric.
It is still another object of the present invention to provide a new two-dimensional or three-dimensional shaped structure formed by the hybrid fabric.
According to the first aspect of the invention there is provided a hybrid fabric. The hybrid fabric comprises in one direction high modulus elongated elements and in another direction low modulus elongated elements.
The low modulus elongated elements keep the high modulus elongated elements at a uniform distance. The low modulus elongated elements having an elongation at break of more than 10%, e.g. more than 50%, e.g. more than 100%, in order to allow stretching of the fabric in the other direction while maintaining the high modulus elongated elements at a uniform distance.
The terms “high modulus elongated elements” refer to elongated elements having a modulus of elasticity E greater than 5000 MPa, e.g. higher than 10000 MPa, e.g. higher than 100000 MPa.
Preferably the high modulus elongated elements have an elongation at break of less than 10%, e.g. less than 5%.
The terms “low modulus elongated elements” refer to elongated elements having a modulus of elasticity E less than 5000 MPa, e.g. less than 4000 MPa, e.g. less than 1500 MPa.
The terms “keep at uniform distance” means that in the other direction the distance between two adjacent high modulus elongated elements is substantially equal along a low modulus elongated element, i.e. shows a uniformity tolerance which is equal to or less than 3 EPDM (=ends per decimetre) along the whole length of the low modulus elongated element.
The terms ‘the other direction’ does not necessarily mean that this direction is perpendicular to the ‘one direction’. The other direction may be perpendicular, oblique (i.e. forming an angle different from 90°) or may even be zigzag with respect to the ‘one direction’.
The hybrid fabric according to the invention makes it possible to obtain high levels of EPDM, e.g. from 14 EPDM to 200 EPDM.
In a preferable embodiment of the invention, the high-modulus elongated elements are in warp direction and the low modulus elongated elements are in weft direction.
Most preferably, the high modulus elongated elements are connected by the low modulus elongated elements by means of any form of endless weaving, circular weaving or by means of shuttle and loom.
Alternatively, the high-modulus elongated elements may be in weft direction and the low modulus elongated elements may be in warp direction. Preferably, the high modulus elongated elements are connected by the low modulus elongated elements by means of a rapier loom or an air jet loom.
According to a second aspect of the invention, the hybrid fabric of the first aspect of the invention is particularly suitable to form a two-dimensional or three-dimensional shaped structure. The two-dimensional or three-dimensional structure is axial-symmetric. The axis of symmetry may be parallel to one of the high modulus elongated elements.
The two-dimensional or three-dimensional shaped structure may comprise band weaves sewed together wherein each of the band weaves is a hybrid fabric according to the first aspect of the invention.
Preferably adjacent band weaves overlap partially with one another.
In an alternative embodiment, the three-dimensional shaped structure may have the high modulus elongated elements being connected by the low modulus elongated elements by means of circular weaving.
The hybrid fabric according to the first aspect of the invention and the two-dimensional structure or three-dimensional structure according to the second aspect of the invention may be used in a carcass of a tire.
The steel cords 12 can be 3×0.14 super tensile steel cords, but any other suitable high modulus elongated element can be used. The modulus of elasticity E of the 3×0.14 ST steel cord is 210 000 MPa. The elongation of this steel cord is 2.72%.
It is to be understood that the invention is not limited to the steel cord construction specified above, but that it may also extend to other possible constructions which can satisfy the end application of the fabric. E.g. for tire application any currently used steel cord could be used in the hybrid fabric as a high modulus elongated element. The steel cord comprises a plurality of steel filaments, ranging from 0.08 mm up to 0.5 mm, preferably from 0.08 mm to 0.30 mm; tensile strengths ranging from normal tensile (2000 MPa) up to mega tensile (4750 MPa).
Steel cord coating could be brass or ternary or quaternary alloys.
Cord constructions could be
Special cords like HE or HI cords and so on.
The elastane elements 14 are made from a synthetic fibre known for its exceptional elasticity. It is a polyurethane-polyurea copolymer. The modulus of elasticity E of elastane is 0.11 cN/dtex (10.46 MPa) and the elongation at break is 550%.
As is clear from
Instead the terms “maintaining the high modulus elongated elements at a uniform distance” mean that along one low modulus elongated element, number 2 high modulus elongated element is at about the same distance from number 1 high modulus elongated element as is number 3 high modulus elongated element from number 2 high modulus elongated element.
Such a structure can easily be handled, stretched and shaped to a carcass net shape and during the whole way of making the carcass net 60 the uniformity of distances between each adjacent steel cords 64 can be successfully kept.
It is to be understood that the invention is not limited to such a hybrid fabric wherein the steel cord as high modulus elongated element and elastane as low modulus elongated element. However, e.g. carbon fibre, glass fibre or Kevlar (Du Pont aramid fiber), Dyneema (DSM HDPE fiber or Polyethylene) or PP (polypropylene) or rayon etc. can also be used as high modulus elongated element and Nylon (polyamide fibre), PEN (polyethylenenaphthalate), or PET (polyester fibre) etc. can also be used as low modulus elongated element.
It is also to be understood that the invention is not limited to the use in a carcass of a tire, but also in many different technical field. Such as medical applications, the carcass net is useful to be pulled over legs and arms or any other three-dimensional structure. Also in construction industry, it is adapted to the reinforcement of concrete or polymer beams or pipes or hoses etc. Besides, it is also adapted to the reinforcement of blades of windmills or sailing masts or any wing-like structures, etc. Further, it is also to be understood that the invention can be used as a reinforcement of structures where a matrix (polymer or concrete or metal etc.) material will be cast or moulded or injection molded etc. around such a reinforcement two-dimensional structure or three-dimensional structure according to the second aspect of the invention.
10 hybrid fabric
12 steel cord
14 elastane
20 band weave
22 steel cord
24 elastane
30, 31 overlapping band weaves
32 zone of overlapping
34 sewing thread
40 two-dimensional structure
42 steel cord
44 elastane
44A/44B/44C separate consecutive elastane parts
50 three-dimensional structure
52 steel cord
54 elastane
56 plaster matrix
60 three dimensional carcass net
62 elastane
64 steel cord
Number | Date | Country | Kind |
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11173944.7 | Jul 2011 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2012/061555 | 6/18/2012 | WO | 00 | 1/13/2014 |