Classifications

• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
  • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
  • D02G3/44—Yarns or threads characterised by the purpose for which they are designed
  • D02G3/48—Tyre cords
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
  • B60C9/0042—Reinforcements made of synthetic materials
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
  • D02G3/00—Yarns or threads, e.g. fancy yarns; Processes or apparatus for the production thereof, not otherwise provided for
  • D02G3/22—Yarns or threads characterised by constructional features, e.g. blending, filament/fibre
  • D02G3/26—Yarns or threads characterised by constructional features, e.g. blending, filament/fibre with characteristics dependent on the amount or direction of twist
  • D02G3/28—Doubled, plied, or cabled threads
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B1/00—Constructional features of ropes or cables
  • D07B1/02—Ropes built-up from fibrous or filamentary material, e.g. of vegetable origin, of animal origin, regenerated cellulose, plastics
  • D07B1/025—Ropes built-up from fibrous or filamentary material, e.g. of vegetable origin, of animal origin, regenerated cellulose, plastics comprising high modulus, or high tenacity, polymer filaments or fibres, e.g. liquid-crystal polymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
  • B60C2009/0071—Reinforcements or ply arrangement of pneumatic tyres characterised by special physical properties of the reinforcements
  • B60C2009/0078—Modulus
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
  • B60C2009/0071—Reinforcements or ply arrangement of pneumatic tyres characterised by special physical properties of the reinforcements
  • B60C2009/0092—Twist structure
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2201/00—Ropes or cables
  • D07B2201/10—Rope or cable structures
  • D07B2201/1012—Rope or cable structures characterised by their internal structure
  • D07B2201/1016—Rope or cable structures characterised by their internal structure characterised by the use of different strands
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2201/00—Ropes or cables
  • D07B2201/10—Rope or cable structures
  • D07B2201/104—Rope or cable structures twisted
  • D07B2201/1044—Rope or cable structures twisted characterised by a value or range of the pitch parameter given
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2201/00—Ropes or cables
  • D07B2201/10—Rope or cable structures
  • D07B2201/104—Rope or cable structures twisted
  • D07B2201/1064—Rope or cable structures twisted characterised by lay direction of the strand compared to the lay direction of the wires in the strand
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2201/00—Ropes or cables
  • D07B2201/20—Rope or cable components
  • D07B2201/2001—Wires or filaments
  • D07B2201/2009—Wires or filaments characterised by the materials used
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2201/00—Ropes or cables
  • D07B2201/20—Rope or cable components
  • D07B2201/2015—Strands
  • D07B2201/2024—Strands twisted
  • D07B2201/2025—Strands twisted characterised by a value or range of the pitch parameter given
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2201/00—Ropes or cables
  • D07B2201/20—Rope or cable components
  • D07B2201/2015—Strands
  • D07B2201/2036—Strands characterised by the use of different wires or filaments
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2205/00—Rope or cable materials
  • D07B2205/20—Organic high polymers
  • D07B2205/2046—Polyamides, e.g. nylons
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2205/00—Rope or cable materials
  • D07B2205/20—Organic high polymers
  • D07B2205/2046—Polyamides, e.g. nylons
  • D07B2205/205—Aramides
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B2501/00—Application field
  • D07B2501/20—Application field related to ropes or cables
  • D07B2501/2046—Tyre cords

Definitions

• the present invention relates to textile reinforcing elements or "reinforcements" that can be used for reinforcing plastic articles or rubber articles such as tires for vehicles.
• Textile cords made from continuous textile fibers such as polyester, nylon, cellulose or aramid fibers, play an important role in tires, including high-performance tires approved for use at very high speeds. To meet the requirements of the tires, they must have a high tensile strength, a high extension modulus, good fatigue endurance and finally good adhesion to rubber matrices or other polymers they are likely to strengthen.
• twines or textile cords traditionally double twisted (T1, T2), are prepared by a twisting process in which: during a first step, each yarn or multifilament fiber (English “yarn”) constitutive of the final cable is first individually twisted on itself (according to an initial twist Tl) in a given direction Dl (respectively S or Z direction), to form a strand (in English " strand ”) in which the elementary filaments are imposed helical deformation around the fiber axis (or axis of the strand);
• the role of the twisting is to adapt the properties of the material in order to create the transverse cohesion of the reinforcement, to increase its resistance to fatigue and also to improve the adhesion with the reinforced matrix.
• Such textile cords, their constructions and manufacturing processes are well known to those skilled in the art. They have been described in detail in a large number of documents, to mention only a few examples in the documents EP 021 485, EP 220 642, EP 225 391, EP 335 588, EP 467 585, US 3,419,060, US 3.
• the present invention relates to a textile cord with at least three twist (Tl, T2, T3), comprising at least N strands, N being greater than 1, twisted together in a twist T3 and a direction D2, each strand consisting of M pre-strands, M being greater than 1, themselves twisted together in a twisting T2 and a direction D1 opposite to D2, each pre-strand itself consisting of a yarn which has been previously twisted on itself; even according to a twist T1 and the direction D1, in which at least half of the N times spun M has an initial modulus in extension noted Mi which is greater than 2000 cN / tex.
• the invention also relates to the use of such a textile cord as a reinforcement element for articles or semi-finished products made of plastic or rubber such as pipes, belts, conveyor belts, tires for vehicles and that these articles, semi-finished rubber products and tires themselves, both in the raw state (that is to say before cooking or vulcanization) and in the cooked state (after cooking).
• a textile cord as a reinforcement element for articles or semi-finished products made of plastic or rubber such as pipes, belts, conveyor belts, tires for vehicles and that these articles, semi-finished rubber products and tires themselves, both in the raw state (that is to say before cooking or vulcanization) and in the cooked state (after cooking).
• the tires of the invention may be intended for motor vehicles of the tourism, 4x4, SUV (Sport Utility Vehicles) type, but also for two-wheeled vehicles such as motorcycles, or for industrial vehicles. selected from vans, "heavy goods vehicles” - ie, metros, buses, road transport vehicles (trucks, tractors, trailers), off-the-road vehicles -, agricultural or civil engineering machinery, airplanes, other transport vehicles or Handling.
• the textile cord of the invention is particularly intended to be used in crown reinforcement (or belts) or in tire carcass reinforcement for the vehicles described above.
• FIGS. 1 to 7 relating to these examples which are diagrammatic (unless otherwise indicated, without respecting a specific scale. ): in cross section, a conventional multifilament textile fiber (or spun), first in the initial state (5) that is to say devoid of torsion, then after a first Tl twist operation in the direction D1, for forming a twisted yarn on itself or "pre-stranded" (10) (Fig. 1);
• any range of values designated by the expression "between a and b" represents the range of values from more than a to less than b (i.e., terminals a and b excluded) while any range of values designated by the expression “from a to b” means the range from a to b (i.e., including the strict limits a and b).
• the high-modulus textile or plied yarn of the invention is therefore (with reference to FIGS. 1 to 3 and 5 appended) a textile cord (30, 50) of very specific construction, which has the essential characteristics of comprising: at least a triple (that is, three or more than three) torsion (T1, T2, T3);
• N at least N strands (20, 20a, 20b, 20c, 20d), N being greater than 1, which are twisted together in a final twist T3 and the same final direction D2;
• each strand consisting of M pre-strands (10, 10a, 10b, 10c), M being greater than 1, themselves twisted together according to an intermediate torsion T2 (T2a, T2b, T2c, T2d) and an intermediate direction D1 opposite at D2;
• each pre-strand consisting of a yarn (5) which has been previously twisted on itself according to an initial twist Tl (Tla, Tlb, Tic) and the initial direction Dl.
• Tl initial twist
• cord having at least one triple twist i.e. three or more twists
• at least three consecutive untwisting (or twisting) operations are therefore necessary for deconstruct the cable of the invention and "go back" to the initial yarns constituting it, that is to say, find the yarns (multifilamentary fibers) starting in their initial state that is to say devoid of torsion.
• Another essential feature is that at least half of the yarns constituting the cord has an initial module in extension denoted Mi which is greater than 2000 cN / tex.
• FIG. 1 schematizes, in transverse section, a conventional multifilament textile fiber (5), also called “yarn” (in English “yarn”), in the initial state, that is to say devoid of twist; in a well known manner, such a yarn is formed of a plurality of elementary filaments (50), typically several tens to several hundred, of very fine diameter generally less than 25 ⁇ .
• pre-strand 10
• the elementary filaments are thus imposed helically deformation around the fiber axis (or axis of the pre-strand).
• M pre-strands for example here three in number: 10a, 10b, 10c
• T2 second twist
• N strands (for example here three in number: 20a, 20b, 20c) are themselves twisted together, in the direction D2 opposite to D1, according to a final twist T3 (third twist ) for forming the final textile cord (30) according to the invention.
• the invention naturally applies to cases where more than three successive twists, for example four (Tl, T2, T3, T4) or five (Tl, T2, T3, T4, T5), would be applied to the yarns. (5) departure.
• the invention is preferably implemented with only three successive operations of torsion (T1, T2, T3), especially for reasons of cost.
• Figure 4, compared to Figure 3, illustrates a conventional method of preparing double twist textile cords.
• M pre-strands for example here three in number, 10a, 10b, 10c
• M pre-strands in fact directly filling the function of strands - are twisted together in a (second) direction D2 opposite the (first) direction of torsion D1 , for direct formation of a double twist textile cord (40) (T1, T2) according to the prior art.
• FIG. 5 schematizes, in cross-section, the assembly of 4 strands (20a, 20b, 20c, 20d) (previously twisted according to T2a, T2b, T2c, T2d in the same direction D1) which are assembled by a third torsion operation T3 in the direction D2 opposite to the direction D1, for forming another example of a final cord (50) with triple torsion (T1, T2, T3) according to the invention.
• Each strand is characterized by a second specific T2 twist (here, T2a, T2b, T2c, T2d) which may be equal to or different from one strand to another.
• FIG. 6 represents, again in cross-section, another representation of the preceding cord (50), less schematic than the preceding one, recalling the well-known fact that the section of a textile cord, that it is moreover whether or not in accordance with the invention, once formed and under a minimum tension, is closer in fact to a cylindrical structure with a substantially circular section, because of the high radial, lateral plasticity of the strands (20a, 20b, 20c, 20d) and pre-strands (10a, 10b, 10c), provided by the multifilament nature of the fibers (spun) starting.
• a polymer spinning process such as, for example, melt spinning, solution spinning or gel spinning.
• non-polymeric material for example mineral material such as glass or non-polymeric organic material such as carbon
• the invention is preferably implemented with - Materials of polymeric material, both thermoplastic type and non-thermoplastic type.
• high modulus textile yarns here, by definition, having a Mi modulus greater than 2000 cN / tex
• PVA polyvinyl alcohol fibers
• aramid fibers aromatic polyester
• PBO polybenzazole fibers
• HDPE high density polyethylene
• the high modulus yarns of the textile cord of the invention are aramid yarns.
• aramid is meant in a well-known manner a polymer consisting of linear macromolecules formed from aromatic groups linked to each other by amide bonds, at least 85% of which are directly bonded to two aromatic rings, and more particularly to poly (p) fibers. phenylene terephthalamide) (or PPTA), manufactured for a long time from optically anisotropic spinning compositions.
• aramid spun yarns include, for example, the fibers marketed by DuPont under the name "Kevlar” by the company Teijin under the names “Twaron” or "Technora”.
• the invention applies to cases where the textile cord of the invention is formed of several yarns of different materials to constitute a hybrid or composite cord, for example of which at least one yarn (that is to say one or more) does not have a modulus Mi greater than 2000 cN / tex, of course at least half of the n times M spun with a Mi module greater than 2000 cN / tex.
• hybrid cords include those based on yarns of at least aramid and nylon, aramid and polyester (eg PET or PEN), aramid and cellulose, or aramid and polyketone.
• N preferably varies in a range from 2 to 6, more preferably from 2 to 4.
• M varies in a range from 2 to 6, more preferably from 2 to 6. 4.
• the total number of yarns (equal to N times M) is in a range from 4 to 25, more preferably from 4 to 16.
• twists can be measured and expressed in two different ways, either simply and in a number of revolutions per meter (t / m), and this is more rigorous when wants to compare materials from - - natures (densities) and / or of different titles, at helix angle of the filaments or what is equivalent in the form of a torsion factor K.
• the torsion factor K is related to the torsion T (here, for example, respectively T1, T2 and T3) according to the following known relation:
• K (Torsion T) x [(Title / (1000.p)] 1/2 in which the torsion T of the elementary filaments (constituting the pre-strand, strand or plied yarn) is expressed in revolutions per meter, the title is expressed in tex (weight in grams of 1000 meters of pre-strand, strand or twisted), and finally p is the density or density (in g / cm 3 ) of the material constituting the pre-strand, strand or plied (for example, about 1.50 g / cm 3 for cellulose, 1.44 g / cm 3 for aramid, 1.38 g / cm 3 for polyester such as PET, 1.14 g / cm 3 for nylon); in the case of a hybrid cable, it is of course an average of the densities weighted by the respective titles of the constituent materials of the pre-strands, strands or twists.
• the twist T1 expressed in revolutions per meter (t / m) is between 10 and 350, more preferably between 20 and 200.
• each pre-strand presents a torsion coefficient K1 which is between 2 and 80, more preferably between 6 and 70.
• the torsion T2 expressed in revolutions per meter is preferably between 25 and 470, more preferably between 35 and 400.
• each strand has a torsion coefficient K2 which is between 10 and 150, more preferably between 20 and 130.
• the torsion T3 expressed in revolutions per meter is preferably between 30 and 600, more preferably between 80 and 500.
• the cord of the invention has a coefficient of K3 twist which is between 50 and 500, more preferably between 80 and 230.
• T2 is greater than T1 (T1 and T2 being in particular expressed in t / m).
• T2 is lower than T3 (T2 and T3 being in particular expressed in t / m), T2 being more preferably between 0.2 and 0.95 times T3, in particular between 0 , 4 and 0.8 times T3.
• the sum T1 + T2 is between 0.8 and 1.2 times T3, more preferably between 0.9 and 1.1 times T3 (T1, T2 and T3 being in particular expressed in t / m), T1 + T2 being in particular equal to T3.
• T1, T2 and T3 being in particular expressed in t / m
• T1 + T2 being in particular equal to T3.
• the majority (in number), more preferably all of the N times M spun (in the initial state, that is to say without the twist Tl) has a module Mi which is greater than 2000 cN / tex, more preferably greater than 2500 cN / tex.
• the initial module in extension Mi, or Young's modulus is of course the modulus in longitudinal extension, that is to say along the axis of the yarn.
• At least half, in particular the majority (in number), of the spun N times M has a modulus Mi greater than 3000 cN / tex, more particularly greater than 3500 cN / tex. Even more preferably, it is the totality of the N times spun which has a modulus Mi greater than 3000 cN / tex, more particularly greater than 3500 cN / tex.
• the titre (or linear density) of the pre-strands, strands or cords is determined on at least three samples, each corresponding to a length of at least 5 m per weighing of this length; the title is given in tex (weight in grams of 1000 m of product - recall: 0, 111 tex equal to 1 denier).
• the mechanical properties in extension are measured in a known manner by means of an "INSTRON" traction machine equipped with "4D” type clamping tongs (for breaking strength less than 100 daN) or “4E” (for breaking strength at least equal to 100 daN), unless otherwise specified in ASTM D885 (2010).
• the tested samples are pulled over an initial length of 400 mm for 4D pliers and 800 mm for 4E pliers, at a nominal speed of 200 mm / min, under a standard pretension of 0.5 cN / tex. All results given are an average of 10 measurements.
• a very low preliminary torsion called "protection twist”, corresponding to a helix angle of about 6 degrees, before positioning and pulling in the clamps.
• the tenacity (force-fracture divided by the title) and the initial modulus in extension (or Young's modulus) are indicated in cN / tex or centinewton by tex (for recall, 1 cN / tex equal to 0.111 g / den (gram by denier)).
• the initial module is represented by the tangent at the origin - - the Force-Elongation curve, defined as the slope of the linear part of the Force-Elongation curve that occurs just after a standard pretension of 0.5 cN / tex.
• the elongation at break is indicated in percentage.
• the textile cord of the invention is advantageously usable for the reinforcement of tires of all types of vehicles, in particular motorcycles, passenger vehicles or industrial vehicles such as heavy vehicles, civil engineering, airplanes, other vehicles for transport or handling.
• Figure 7 shows very schematically (without respecting a specific scale), a radial section of a tire according to the invention for example for tourism type vehicle.
• This tire 100 has a top 102 reinforced by a crown reinforcement or belt 106, two sidewalls 103 and two beads 104, each of these beads being reinforced with a rod 105.
• the top 102 is surmounted by a tread not shown on this schematic figure.
• a carcass reinforcement 107 is wrapped around the two rods in each bead, the upturn 108 of this armature 107 being for example disposed towards the outside of the tire 100 which is shown here mounted on its rim 109.
• the carcass reinforcement 107 is in known manner constituted by at least one rubber ply reinforced by so-called "radial" textile cords, that is to say that these cords are arranged substantially parallel to one another and extend from one bead to the other so as to form an angle of between 80 ° and 90 ° with the median circumferential plane (plane perpendicular to the axis of rotation of the tire which is situated halfway between the two beads 104 and goes through the middle of the vertex frame 106).
• the belt 106 is for example constituted, in a manner known per se, by at least two layers of rubber called "working plies” or “triangulation plies”, superimposed and crossed, reinforced with metal cables arranged substantially parallel to each other with respect to others and inclined relative to the median circumferential plane, these working plies may or may not be associated with other plies and / or fabrics of rubber. These working plies have the primary function of giving the tire a high rigidity of drift.
• the belt 106 further comprises in this example a rubber sheet called "shrink web" reinforced by so-called “circumferential” reinforcing son, that is to say that these reinforcing son are arranged substantially parallel to each other and extend substantially circumferentially around the tire so as to - - form an angle preferably within a range of 0 to 10 ° with the median circumferential plane.
• These circumferential reinforcing son have the primary function, it is recalled, to resist the centrifugation of the top at high speed.
• this tire 100 of the invention has the essential feature that at least the shrinking web of its belt (106) and / or its carcass reinforcement (107) comprises a textile cord according to the invention.
• the rods (105) which could consist, in whole or in part, of a textile cord according to the invention.
• the rubber compositions used for these plies are conventional compositions for calendering textile reinforcements, typically based on natural rubber or other diene elastomer, a reinforcing filler such as carbon black, a vulcanization system and additives. conventional.
• a reinforcing filler such as carbon black
• a vulcanization system and additives.
• the adhesion between the composite textile cord of the invention and the rubber layer which coats it is ensured for example by a usual adhesive composition, for example an adhesive of the RFL type or equivalent adhesive.
• the textile cord of the invention has significantly improved tensile properties, as demonstrated by the following embodiments.
• the starting yarns are of course commercially available, for example nylon sold by the company Kordsa under the name “T728", or by the company PHP under the names “Enka 140HRT or” Enka 444HRST ", for the aramid by the DuPont company under the name “Kevlar” or by the company Teijin under the name “Twaron”.
• - -
• toughness is the breaking force reported in the title, it is expressed in cN / tex. Also indicated is the apparent toughness (in daN / mm 2 ), in this case the breaking force is referred to the apparent diameter noted 0 which is measured according to the following method.
• An apparatus is used which, using a receiver composed of a collecting optical system, a photodiode and an amplifier, makes it possible to measure the shadow of a wire illuminated by a parallel light LASER beam. with an accuracy of 0.1 micrometer.
• Such a device is marketed for example by the company Z-Mike, under the reference "1210".
• the method consists in fixing on a motorized moving table, under a standard pretension of 0.5 cN / tex, a sample of the wire to be measured, having been pre-conditioned. Solidary of the moving table, the wire is moved perpendicularly to the shadow measurement system at a speed of 25 mm / s and orthogonally cuts the beam LASER. At least 200 measurements of shadows are made over a length of 420 mm of wire; the average of these drop shadow measurements represents the apparent diameter 0.
• breaking strength, toughness and apparent toughness were also given in relative values, with the base 100 being used for the control cord of each of the five tests.
• control cords (denoted “T” in Table 1) are all characterized by a conventional double-twist construction T1, T2; the other wired (comparative non-compliant with the invention, or in accordance with the invention) are all characterized by an unconventional construction with triple torsion Tl, T2, T3. Only cords C8, C9 and C1 are in accordance with the invention and combine the triple twist characteristic and the fact of being made of high modulus yarns (in these examples, aramid yarns).
• control cable C 1 the construction denoted by "N47 / - / 3/4" of the control cable C 1 signifies that this cable is a double-twist cable (T1, T2) which is obtained simply from a twisting operation (T2, D2 or S) of 4 different strands which were each prepared beforehand by a reverse twist operation (Tl, Dl or Z) of 3 nylon spun yarns (N) of title 47 tex.
• N47 / 1/3/4 of the cord C2 signifies that this cord is a triple twist cord (T1, T2, T3) which is derived from a final twisting operation (T3, D2 or S) of 4 different strands which have each been prepared beforehand by an intermediate twisting operation (T2) in the opposite direction (D1 or Z) of 3 pre-strands, each of these 3 pre-strands consisting of 1 single spun nylon (N) of Title 47 tex which has been previously twisted on itself during a first twisting operation T1 in the same direction (D1 or Z) as for the pre-strands.
• T1, T2, T3 which is derived from a final twisting operation (T3, D2 or S) of 4 different strands which have each been prepared beforehand by an intermediate twisting operation (T2) in the opposite direction (D1 or Z) of 3 pre-strands, each of these 3 pre-strands consisting of 1 single spun nylon (N) of Title 47 tex which has been previously twisted on itself during a first twisting operation T1 in the same direction (
• the exemplary control cords ("T") C1, C3, C5, C7 and C10 are all characterized by a double twist construction; they were manufactured by assembling 2, 3 or 4 strands according to a (second) final twist (T2) varying from 150 to 300 t / m depending on the case, corresponding to a torsion coefficient K2 ranging from 175 to 215 and a direction D2 (S direction). Conventionally, each of these strands had been previously manufactured by a (initial) initial twist (denoted Tl) of 150 to 300 t / m, depending on the case, of a yarn on itself in the opposite direction Dl (direction Z).
• cords according to the invention C8, C9 and C1 are characterized by a triple twist construction Tl, T2, T3 (in these example, Z / Z / S); they were manufactured by assembling 3 or 4 strands in a final twist (denoted T3) of 150 or 300 t / m (K3 203 or 215) and a direction D2 (S direction).
• each of these strands had been previously manufactured by assembling 3 pre-strands according to a T2 twist (110, 180 or 240 t / m) and an opposite direction D1 (Z direction), each of these pre-strands having was itself prepared beforehand by a twist Tl (respectively 40, 120 or 60 t / m) of a yarn on itself, in the direction Dl (Z direction).
• T2 twist 110, 180 or 240 t / m
• D1 Z direction
• the invention therefore makes it possible, for the same given final twist, to improve the properties of compactness, breaking strength and toughness of high modulus textile cords such as aramid cords.
• their new construction gives them endurance in compression or flexion-compression which also is significantly improved, as attested by the results of endurance tests that follow.
• fatigue resistance can be analyzed by subjecting these cords to various known laboratory tests, in particular to the fatigue test known as a "belt” test sometimes called “Shoe”. Shine test ", or the fatigue test called” Disc Fatigue Test "(see for example EP 848 767, US 2,595,069, US 4,902,774, ASTM D885-591 revised 67T), tests in which the textile cords, previously glued, are incorporated in a rubber article that is vulcanized.
• the belt comprises two layers of the cord to be tested, in a known rubber mixture of the type commonly used for reinforcing tires.
• the axis of each cord is oriented in the longitudinal direction of the belt and the cords are separated from the faces of the latter by a gum thickness of about 1 mm.
• This belt is then subjected to the following stresses: the belt around a roller of a given diameter is cyclically driven, using a crank-handle system, so that each elementary portion of the belt is subjected to a tension of 15 daN and undergo cycles of variation of curvature which make it pass from an infinite radius of curvature to a given radius of curvature and this during 190 000 cycles, with a frequency of 7 Hz.
• the cords of the layer are extracted by shelling. - - Interior and measure the residual breaking strength of tired cords.
• the "Disc Fatigue Test” is another test well known to those skilled in the art, it consists essentially in incorporating test cords into rubber blocks, then, after cooking, to fatigue the gum specimens thus formed in compression, between two rotating disks, a very large number of cycles (in the examples which follow, 600 000 cycles at 33 cycles / s). After fatigue, the cords are extracted from the test pieces and their residual breaking force is measured.
• the cords C1 to C4, and C7 not in accordance with the invention and the C8 and C9 cords according to the invention of the previous tests were submitted on the one hand to the "Disc Fatigue Test” with a rate of maximum geometrical compression of the test piece by about 16% (3 ° angle between the two discs), on the other hand the “Shoe Shine test” with a geometric compression ratio of the cords of the inner layer of about 12% (20 mm roller).
• test 6 of Table 2 The above tests were completed by an additional endurance test (test 6 of Table 2) carried out on two other textile cords C12 (control) and C13 (invention), based on high modulus yarns as for test 4 previous, both having a final torsional coefficient (respectively K2 or K3) identical (equal to about 180) to those retained for the nylon controls of the preceding tests 1 to 3.
• the construction denoted "A55 / - / 3/3" of the control cable C12 means that this cord is a double-twisted cord (T1, T2) which is simply the result of a twisting operation ( 310 t / m T2, D2 or S) of 3 different strands which were each prepared beforehand by an individual torsional operation in the opposite direction (T1 of 310 t / m, Dl or Z) of 3 aramid yarns (A) of title 55 tex.
• the textile cord concerned is a triple twist cord (T1, T2, T3) which is derived from a torsion operation final (T3 of 310 t / m, D2 or S) of 3 different strands which were each prepared beforehand by an intermediate twisting operation (T2 of 185 t / m) in the opposite direction (D1 or Z) of 3 pre-strands , each of the pre-strands consisting of 1 aramid single yarn (A) of title 55 tex which has been previously twisted on itself during a first twist operation T1 (125 t / m) in the same direction D1 ( Z).
• T1, T2, T3 which is derived from a torsion operation final (T3 of 310 t / m, D2 or S) of 3 different strands which were each prepared beforehand by an intermediate twisting operation (T2 of 185 t / m) in the opposite direction (D1 or Z) of 3 pre-strands , each of the pre-strands consisting of 1 aramid single

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• Textile Engineering (AREA)
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• Crystallography & Structural Chemistry (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Tires In General (AREA)
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• 2014
  • 2014-12-09 FR FR1462105A patent/FR3029542B1/fr not_active Expired - Fee Related
• 2015
  • 2015-12-07 CN CN201580067353.6A patent/CN107002314B/zh active Active
  • 2015-12-07 WO PCT/EP2015/078841 patent/WO2016091812A1/fr not_active Ceased
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