JP2017538049A - Textile cord with at least triple twist - Google Patents

Abstract

A textile cord (50) having at least a triple twist (T1, T2, T3) comprises at least N strands (20a, 20b, 20c, 20d) twisted together in a final twist T3 and a final direction D2, N Is greater than 1 and each strand is itself M twisted strands (10a, 10b, T2a, T2b, T2c, T2d) and twisted together in an intermediate direction D1 opposite to D2. 10c), where M is greater than 1 and each spare strand itself consists of a yarn (5) pre-twisted itself with an initial twist T1 (T1a, T1b, T1c) and direction D1, N × At least half of the M yarns have an initial modulus expressed as Mi, greater than 800 cN / tex. This textile cord can advantageously be used as a reinforcement in vehicle tires, in particular in the belts or carcass reinforcements of these tires. [Selection] Figure 5

Description

  The present invention relates to textile reinforcement elements or “reinforcements” that can be used to reinforce plastic articles or rubber articles such as vehicle tires.

  The present invention more particularly relates to textile cords or twisted yarns that can be used in particular to reinforce such tires.

  Textiles have been used as a reinforcement since tires first appeared.

  Textile cords made from continuous textile fibers such as polyester, nylon, cellulose or aramid fibers are known to play an important role in tires and also in high performance tires certified for ultra high speed running. In order to meet tire requirements, they have high fracture strength, high modulus, excellent fatigue durability, and finally excellent rubber or other polymer matrix that will be subject to reinforcement. It is necessary to have adhesiveness.

It can easily be recalled here that these textile yarns or cords are traditionally of the double twist (T1, T2) type and are made by a process known as twisting, In the method
-During the first step, each multifilament fiber or yarn making up the final cord is initially individually (in the initial twist T1) in a given direction D1 (in the S or Z direction, respectively) Twisted to form a strand, in which the element filaments are helically deformed around the fiber axis (or strand axis).
Then, during the second step, several strands, generally 2, 3 or 4 strands, which are identical in nature or different in the case of cords called hybrids or composites, are then finally twisted In T2 (which may be the same as or different from T1) and in the opposite direction D2 (Z or S direction, respectively, according to an accepted naming convention for the direction of rotation according to the S or Z diagonal) Together to obtain a cord or final assembly comprising several strands.

  The purpose of twisting is to adapt the properties of the material in order to produce a cohesive force in the transverse direction of the reinforcement, to increase its fatigue durability and to improve its adhesion to the matrix to be reinforced.

  Such textile cords, their structure and manufacturing methods are known to those skilled in the art. These are numerous documents, for example, Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, Patent Document 5, Patent Document 6, Patent Document 7, Patent Document 8 and Patent This is described in detail in Document 9, Patent Document 10, or Patent Document 11, or more recently, Patent Document 12, Patent Document 13, and Patent Document 14.

European Patent No. 021485 specification European Patent No. 220642 European Patent 225391 European Patent No. 335588 European Patent No. 467585 U.S. Pat. No. 3,419,060 US Pat. No. 3,997,172 U.S. Pat. No. 4,155,394 US Pat. No. 5,558,144 International Publication No. 97/06294 European Patent No. 848767 International Publication No. 2012/104279 International Publication No. 2012/146612 International Publication No. 2014/057082

  In order to be able to reinforce rubber articles such as tires, the fatigue strength (tensile, bending, compression durability) of these textile cords is an important key. In general, the greater the twist applied to a given material, the higher this fatigue strength, but correspondingly the tensile breaking load of the textile cord (called tenacity when expressed per unit weight) ) Is known to inevitably decrease as the twist increases, which is naturally disadvantageous from a reinforcement standpoint.

  For this reason, textile cord designers such as tire manufacturers are always looking for textile cords that can improve the mechanical properties, especially breaking load and tenacity, for a given material and a given twist. Yes.

  Currently, in the course of research, Applicants can unexpectedly improve the breaking load and tenacity characteristics for a given material and a given final twist unexpectedly. I found a new textile code specifically.

  Thus, according to a first subject, the invention relates to a textile cord of at least triple twist (T1, T2, T3), which textile cord comprises at least N strands twisted together in a twist T3 and direction D2. N is greater than 1 and each strand is composed of M pre-strands that are themselves twisted together in the direction D1 opposite to the twists T2 and D2, where M is greater than 1. , Each spare strand itself consists of a yarn that has been pre-twisted in twist T1 and direction D1, and at least half of the N × M yarns has an initial elasticity represented by Mi, higher than 800 cN / tex Have a rate.

  The invention also relates to the use of such textile cords as reinforcing elements for plastic or rubber articles or semi-finished products such as pipes, belts, conveyor belts, vehicle tires, That is, it relates to these rubber articles and semi-finished products and the tire itself, both before curing or vulcanization) and in the cured state (after curing).

  The tires of the present invention can be specifically designed for passenger cars, 4 × 4, or SUB (sports utility vehicles) type automobiles, but for motorcycles such as motorbikes, vans, heavy duty vehicles, Ie intended for industrial vehicles selected from subway vehicles, buses, road transport vehicles (trucks, tractors, trailers) and off-road vehicles, agricultural or civil engineering equipment, aircraft, other transport or work vehicles. You can also.

  More specifically, the textile cord of the present invention is intended for use in the crown reinforcement (or belt) or carcass reinforcement of the vehicle tire.

  The present invention and its advantages are illustrated in the detailed description and exemplary embodiments that follow and from FIG. 1 associated with these embodiments (not drawn to a specific scale unless otherwise indicated). It will be easily recognized in view of FIG.

First, it shows the initial state (5) of a conventional multifilament textile fiber (or yarn), i.e. untwisted, and then the yarn itself twisted, i.e. "preliminary strand" (10) It is sectional drawing which shows after 1st twist operation T1 of the direction D1 for forming A. For the formation of the strand (20) intended for the cord according to the invention, a spare strand (previously in the same direction D1 in T1a, T1b, T1c), assembled by a second twisting operation T2 in the same direction D1. FIG. 2 is a cross-sectional view showing an assembly of three yarns (10a, 10b, 10c) as described above functioning as being twisted). For the formation of the final textile cord (30) with triple twist (T1, T2, T3) according to the invention, this time assembled by a third twisting operation T3 in the direction D2 opposite to the direction D1, FIG. 6 is a cross-sectional view showing an assembly of three strands (20a, 20b, 20c) as such (previously twisted in the same direction D1 at T2a, T2b, T2c). For the formation of a textile cord (40) according to the prior art with double twists (T1, T2), it was assembled directly by a second twisting operation T2 in the direction D2 opposite to the direction D1, this time directly a strand FIG. 2 is a cross-sectional view showing a conventional assembly of three yarns (10a, 10b, 10c) as described above that function as (all twisted in the direction D1 at T1a, T1b, T1c in advance). For the formation of the final textile cord (50) with triple twist (T1, T2, T3) according to the invention, it was assembled by a third twisting operation T3 in the direction D2 opposite to the direction D1 (previously T2a , T2b, T2c, T2d is a cross-sectional view showing an assembly of four strands (20a, 20b, 20c, 20d) twisted in the same direction D1. Once formed, the final cross section of the textile cord under minimal tension (whether it is or not according to the invention) has a high degree of lateral plasticity brought about by the multifilament nature of the starting material Therefore, it is a cross-sectional view that is less schematic than the previous view of the cord (50), showing the fact that it is actually more similar to the cross-section of the circular contour. Finally, it is a radial cross-sectional view (which means the plane containing the axis of rotation of the tire) showing an example of a tire according to the invention incorporating a textile cord according to the invention.

  In this application, all percentages (%) are percentages by mass unless otherwise indicated.

  The interval of values represented by the expression “between a and b” represents a range of values ranging from a value greater than a to a value less than b (ie excluding the endpoints a and b), while “ A value interval represented by the expression “from a to b” means a range of values ranging from a to b (ie, strictly including the end points a and b).

Thus, the textile cords or plied yarns of the present invention are highly specific structured textile cords (30, 50) (see attached FIGS. 1 to 3 and 5), which are: It has essential features including
-At least triple (which means 3 or more than 3) twists (T1, T2, T3).
-At least N strands (20, 20a, 20b, 20c, 20d) twisted together in the final twist T3 and final direction D2, where N is greater than 1.
Each strand is itself M intermediate strands T2 (T2a, T2b, T2c, T2d) and M spare strands (10, 10a, 10b, 10c) twisted together in the direction D1 opposite to D2. Configured, and M is greater than 1.
Each spare strand consists of yarn (5) pre-twisted in itself with an initial twist T1 (T1a, T1b, T1c) and an initial direction D1.

  A person skilled in the art, from the expression of a cord having at least a triple twist (meaning having three or more twists), "disassembles" the cord of the present invention and "returns" it back to the initial yarn that constitutes it. In other words, it is immediately necessary that at least three successive untwisting (or twisting in opposite directions) operations are necessary to find the starting yarn (multifilament fiber) in its initial state, ie, untwisted. Will understand. In other words, forming the cord of the present invention involves at least three (three or more) sequential twisting operations instead of two as usual.

  Another essential feature is that at least half of the yarns that make up the cord need to have an initial modulus Mi higher than 800 cN / tex (this specifically excludes nylon fibers), otherwise No improvement in breaking load and tenacity is observed.

  The structure of the textile cord of the present invention and the steps involved in its manufacture will now be described in detail.

  First, FIG. 1 schematically shows a cross section of a conventional multifilament textile fiber (5), also known as “yarn”, in its initial state, ie untwisted. As is well known, such yarns are formed from a plurality of, typically tens to hundreds of element filaments (50), of very fine diameters generally less than 25 μm.

  After twisting operation T1 (first twist) in direction D1 (S or Z), the initial yarn (5) is converted into a yarn known as “preliminary strand” (10), which is twisted on itself. The Thus, within this spare strand, the element filaments are helically deformed around the fiber axis (or the spare strand axis).

  Then, as shown by way of example in FIG. 2, M spare strands (e.g., three of which are 10a, 10b, 10c) are then placed in the same direction D1 as before, with an intermediate twist T2 (second Are twisted together to form a “strand” (20). Each spare strand is characterized by a specific first twist T1 (eg here T1a, T1b, T1c), which is also equal (the general case, ie here T1a = T1b = T1c) Yes, or the spare strands may be different from each other.

  Finally, as schematically shown in FIG. 3, N strands (for example, three strands 20a, 20b, and 20c here) are then subjected to a final twist T3 (in the direction D2 opposite to D1). In a third twist) themselves are twisted together to form the final textile cord (30) according to the invention. Each strand is characterized by a specific second twist T2 (eg here T2a, T2b, T2c), which may be the same (general case, ie here T2a = T2b = T2c, for example) Or may vary from strand to strand.

  Thus, the final textile cord (30) obtained in this way and containing N × M (here 9 for example) spare strands is characterized by (at least) triple twist (T1, T2, T3).

  The present invention, of course, gives more than 3 sequential twists, eg 4 times (T1, T2, T3, T4) or 5 times (T1, T2, T3, T4, T5) to the starting yarn (5). It also applies when However, it is preferred that the present invention be implemented in exactly three sequential twisting operations (T1, T2, T3), especially for cost reasons.

  FIG. 4 shows a conventional method of making a double twisted textile cord in comparison with FIG. M spare strands (for example, three strands 10a, 10b, and 10c in this case) actually function directly as strands, which are opposite to the (first) twist direction D1 (the first strand). 2) and twisted together in direction D2, directly forming a double twisted (T1, T2) textile cord (40) according to the prior art.

  FIG. 5 schematically shows a cross section of an assembly of four strands (20a, 20b, 20c, 20d) (previously twisted in the same direction D1 with T2a, T2b, T2c, T2d), Another example of a final cord (50) assembled by a third twisting operation T3 in the direction D2 opposite to the direction D1 and having a triple twist (T1, T2, T3) according to the invention. Each strand is characterized by a particular second twist T2 (eg, here T2a, T2b, T2c, T2d), which may be the same or different for each strand.

  As a precaution, FIG. 6 shows another view of the cord (50) that is less schematic than the previous view, again in cross-section, and once formed, a cross-section of the textile cord under minimal tension. Incidentally, the strands (20a, 20b, 20c, 20d) and the spare strands (10a, 10b, 20d), which are given by the multifilament nature of the strand fibers (yarn), whether or not according to the present invention. Recall the well-known fact that due to the high degree of lateral radial plasticity of 10c), in practice it approaches a cylindrical structure with an essentially circular contour.

  In this application, “textile” or “textile material” means very generally a natural or synthetic material that can be converted into threads, fibers or films by any suitable conversion method. Any material made of any material other than metal. Non-limiting examples include polymer spinning methods such as melt spinning, wet spinning or gel spinning.

  While materials made of non-polymeric materials (eg, minerals such as glass or non-polymeric organic materials such as carbon) are also included in the definition of textile materials, the present invention includes polymeric materials of either thermoplastic or non-thermoplastic type It is preferably carried out using a material made of

  Examples of thermoplastic or other types of polymeric materials include, for example, cellulose, especially rayon, polyvinyl alcohol (abbreviated PVA), polyketone, aramid (aromatic polyamide), aromatic polyester, polybenzazole (abbreviated PBO), polyimide, Polyesters, particularly those selected from PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PBT (polybutylene terephthalate), PBN (polybutylene naphthalate), PPT (polypropylene terephthalate), PPN (polypropylene naphthalate), Can be mentioned.

  Of course, the present invention also provides that when the textile cord of the present invention is formed of several yarns of different materials to build a hybrid or composite yarn, for example, at least polyester and nylon, only to name a few Or polyester and cellulose, or polyester and polyketone, or polyketone and nylon, or cellulose and nylon, or cellulose and polyketone, or cellulose and aramid, or aramid and nylon, or aramid and polyester (for example, PET or PEN), and aramid Applied when based on polyketone yarns, at least half of the N × M yarns of course have a modulus Mi higher than 800 cN / tex.

  In the cord of the present invention, N preferably varies from 2 to 6, more preferably from 2 to 4. According to another preferred embodiment, M varies from 2 to 6, more preferably from 2 to 4. According to another preferred embodiment, the total number of yarns (equal to N × M) is in the range from 4 to 25, more preferably from 4 to 16.

In a manner well known to those skilled in the art, twist can be measured and expressed in two different ways, i.e. expressed in revolutions per meter (t / m) in the simplified method, or different properties (cubic density) ) And / or if a comparison of different yarn count materials is desired, it is more precisely expressed by the twist angle of the filament or in the form of a twist factor K. The twist coefficient K is related to the twist T (here, for example, T1, T2, and T3, respectively) by the following known relationship.
K = (twisted T) × [(yarn count / (1000 · ρ)] ^1/2
Here, the twist T of the element filament (which constitutes a spare strand, a strand or a twisted yarn) is expressed in meters per rotation (t / m), and the yarn count is tex (a spare strand, a strand or a twisted yarn 1000). Finally, ρ is the density or cubic density (g / cm ³ ) of the material making up the prestrand, strand or plied yarn (eg approximately 1.50 g for cellulose) / cm ^3, in the case of aramid, when a polyester such as ^{1.44g / cm 3, PET, 1.38g} / cm 3, a case of nylon 1.14 g / cm ^3), when the hybrid cord, [rho is Of course, the average of the density weighted by the yarn count of each of the materials that make up the spare strand, strand or plied yarn .

  In the cord of the present invention, preferably the twist T1 expressed in revolutions per meter (t / m) is comprised between 10 and 350, more preferably between 20 and 200. According to another preferred embodiment, each spare strand has a twist factor K1 comprised between 2 and 80, more preferably between 6 and 70.

  According to another preferred embodiment, the twist T2, expressed in revolutions per meter, is preferably comprised between 25 and 470, more preferably between 35 and 400. According to another preferred embodiment, each strand has a twist factor K2 comprised between 10 and 150, more preferably between 20 and 130.

  According to another preferred embodiment, the twist T3 expressed in revolutions per meter is preferably comprised between 30 and 600, more preferably between 80 and 500. According to another preferred embodiment, the cord of the invention has a twist factor K3 comprised between 50 and 500, more preferably between 80 and 230.

  Preferably T2 is greater than T1 (T1 and T2 are in particular expressed in t / m). According to another preferred embodiment, which may or may not be combined with said embodiment, T2 is smaller than T3 (T2 and T3 are in particular expressed in t / m), and T2 is more preferably T3. Between 0.2 times and 0.95 times, in particular between 0.4 times and 0.8 times T3.

  According to another embodiment, the sum T1 + T2 is comprised between 0.8 and 1.2 times T3, more preferably between 0.9 and 1.1 times T3 (T1, T2 and T3 are expressed in particular in t / m), T1 + T2 is specifically equal to T3.

  In the cord according to the invention, preferably the majority (number basis) of the N × M yarns, more preferably all (in the initial state, ie without the twist T1), higher than 800 cN / tex. In particular, it has an elastic modulus Mi higher than 1000 cN / tex. The initial elastic modulus Mi or Young's modulus is of course the elastic modulus in the longitudinal direction, i.e. the elastic modulus along the axis of the yarn.

  Even more preferably, at least half of the N × M yarns, in particular the majority (number basis), have a modulus of elasticity Mi higher than 1200 cN / tex, more specifically higher than 1400 cN / tex. Even more preferably, all of the N × M yarns have a modulus of elasticity Mi higher than 1000 cN / tex, in particular higher than 1200 cN / tex, more specifically higher than 1400 cN / tex.

  All the properties shown above (yarn count, yarn initial modulus, breaking strength and tenacity) are preconditioned, bare cord (which means uncoated) cord or coated cord (which is used It is determined at 20 ° C. with respect to a cord that is ready to be prepared, or a cord that has been removed from the article to be reinforced. “Preconditioning” means that the cord (after drying) is stored at least 24 hours in a standard atmosphere (temperature 20 ± 2 ° C., relative humidity 65 ± 2%) according to European standard DIN EN20139 before measurement. To do.

  The yarn count (or linear density) of the preliminary strand, strand or cord is determined by weighing this length for at least three samples, each corresponding to a length of at least 5 m, (Gram weight of product 1000 m (note that 0.111 tex is equal to 1 denier)).

  The tensile mechanical properties (tenacity, initial modulus, elongation at break) are in accordance with standard ASTM D885 (2010) unless otherwise specified, “4D” type (for breaking strength less than 100 daN) or “4E” type. It is measured in a known manner using an INSTRON tensile tester equipped with a capstan grip (for breaking strength equal to at least 100 daN). The specimens are subjected to traction at a nominal speed of 200 mm / min under a standard pretension of 0.5 cN / tex over an initial length of 400 mm for 4D grips and 800 mm for 4E grips. All results obtained are an average of 10 measurements. When measuring the properties of the yarn, the yarn is subjected to a very light pre-twist, known as “protective twist”, corresponding to a twist angle of about 6 degrees, in a known manner before being placed in the grip and tensioned. receive.

  Tenacity (breaking strength divided by yarn count) and initial modulus (or Young's modulus) are given in cN / tex, or centnewton tex (1 cN / tex is 0.111 g / den (denier per gram)). Note that this is equal to The initial modulus is represented by the tangent at the origin of the force-elongation curve and is described as the slope of the linear portion of the force-elongation curve that occurs immediately after the standard pretension of 0.5 cN / tex. The elongation at break is expressed as a percentage.

  The textile cord of the invention is advantageously used for tires of all types of vehicles, in particular motorbikes, passenger cars or industrial vehicles such as heavy duty vehicles, construction plant vehicles, aircraft, other transport or work vehicles. Can be used to reinforce.

  By way of example, FIG. 7 shows quite schematically (not to scale) a radial cross section of a tire according to the invention, for example for a passenger vehicle type vehicle.

  The tire 100 includes a crown 102 reinforced by a crown reinforcement or a belt 106, a sidewall 103, and two beads 104, each of which is reinforced by a bead wire 105. On the crown 102, a tread not drawn in this schematic diagram is placed. A carcass reinforcing body 107 is wound around two bead wires in each bead, and the folded portion 108 of the reinforcing body 107 is, for example, the outer side of the tire 100 depicted in a state of being attached to the rim 109 here. Is positioned towards

  In a manner known per se, the carcass reinforcement 107 is composed of at least one rubber ply reinforced with what is known as a “radial” textile cord, where “radial” means that these cords are substantially parallel to each other. And 80 ° and 90 ° to the circumferential center plane (a plane perpendicular to the tire rotation axis, which is located between the two beads 104 and passes through the center of the crown reinforcement 106) It means extending from one bead to the other so as to form an angle between them.

  The belt 106 is composed, for example, of at least two rubber plies called “working ply” or “triangulation ply” in a manner known per se, which are superimposed and intersecting, These working plies are tied or not tied to other rubber plies and / or fabrics, arranged parallel to each other and inclined with a metal cord inclined relative to the circumferential center plane. These working plies have the main function of imparting high cornering rigidity to the tire casing. The belt 106 further includes a rubber ply called “hooping ply” in this example, which is reinforced with a reinforcing thread called “circumferential”, which means that these reinforcing threads are effectively They are arranged parallel to each other and extend substantially circumferentially around the tire casing so as to form an angle with respect to the circumferential center plane, preferably in the range of 0 ° to 10 °. Means that. It is recalled that these circumferential reinforcing threads have the main function of resisting spin-out of the crown at high speeds.

  This tire 100 according to the invention has the essential feature that, for example, at least the ooping ply of the belt (106) and / or the carcass reinforcement (107) comprises a textile cord according to the invention. According to another possible exemplary embodiment of the present invention, it is for example a bead wire (105) that is constituted in whole or in part by the textile cord according to the present invention.

  The rubber compositions used for these plies are conventional for textile reinforcement skimming, typically with natural rubber or some other diene elastomer and a reinforcing filler such as carbon black. Based on material and vulcanization system and conventional additives. Adhesion between the composite textile cord of the present invention and the rubber layer covering it is provided, for example, by a conventional adhesive composition, such as an RFL type or equivalent adhesive.

  Because of its particular structure, the textile cord of the present invention has particularly improved tensile test properties, as demonstrated by the following exemplary embodiments.

  In these exemplary embodiments, six different tensile tests were initially performed with a total of 13 different textile cords based on nylon, rayon or aramid, according to or not according to the invention.

  The type of each example of code ("T" is a control, "C" is a comparative example, and "I" is according to the present invention), the materials used ("N" is nylon, "R" is rayon, "A" “Aramid”), its structure and final properties are summarized in the attached Table 1.

  The starting yarn is of course commercially available, for example in the case of nylon, sold by Kordsa under the name “T728”, or from PHP under the name “Enka 140HRT” or “Enka 444HRST”, in the case of rayon Cordenka is sold under the name “C610-F Super2”, and in the case of aramid, it is sold under the name “Twaron 1000” from Teijin.

As already indicated, tenacity is the force at break against yarn count and is expressed in cN / tex. Apparent tenacity (daN / mm ² ) is also shown, where the force at break is relative to the apparent diameter, expressed as Φ, measured according to the following method.

  Using a receiver with a condensing system, a photodiode, and an amplifier, it is possible to measure the shadow of a thread illuminated by a parallel laser beam with an accuracy of 0.1 micrometer. Become. Such a device is marketed, for example, under the product number “1210” by Z-Mike. The method includes securing a pre-conditioned specimen of a thread to be measured to a motorized movable table under a standard preload of 0.5 cN / tex. When fixed to a movable table, the sled is moved at a speed of 25 mm / sec perpendicular to the cast-shadow measurement system and intersects the laser beam orthogonally. On a 420 mm long thread, at least 200 shadow projection measurements are taken and the average of these shadow projection measurements represents the apparent diameter Φ.

  For each test, the rupture load, tenacity, and apparent tenacity were also expressed as relative values with the control code in each test as 100.

  The control cords (represented by “T” in Table 1) are all characterized by a conventional double twisted T1, T2 structure, and the other cords (comparative examples or according to the invention) are all different triple twists. Characterized by T1, T2, T3 structures. However, only the cord according to the present invention combines the triple twist characteristics with an initial yarn modulus higher than 800 cN / tex.

  In order to make this Table 1 easier to read, here, for example, the structure represented by “N47 / − / 3/4” for the control cord C1, the cord is simply twisted with four different strands (T2 , D2 or S), and each of the different strands individually twists three nylon (N) yarns of yarn count 47 tex in the reverse direction (T1 Note that it is pre-made by D1, or Z).

  For comparison, in the case of the structure represented by “N47 / 1/3/4” (code C2), the textile cord is derived from the final twisting operation (T3, D2 or S) of four different strands. Triple twisted (T1, T2, T3) cords, each of the different strands made in advance by an intermediate twisting operation (T2) in the reverse direction (D1 or Z) of three spare strands Each of the spare strands consists of a single nylon (N) yarn of yarn count 47 tex, which itself has been pre-added during the first twisting operation T1 in the same direction D1 (Z). It is twisted.

  The six examples C1, C3, C5, C7, C9 and C12 of the control cord (denoted “T”) are all characterized by a double twisted structure, which consists of two, three or four strands. Manufactured by assembling with a (second) final twist (denoted T2) from 150 t / m to 300 t / m corresponding to a twist factor K2 varying from 175 to 215, and direction D2 (S direction) Is. In a conventional manner, each of these strands is (first) initial twist (denoted T1) in the opposite direction D1 (Z direction), optionally from 150 t / m to 300 t / m, depending on the yarn itself. And pre-manufactured.

  The four examples C8, C10, C11 and C13 of the cords according to the invention (represented by “I” and shown in bold in Table 1) are all triple twisted T1, T2, T3 structures (in these examples Z / Z / S), which is a final twist of 150 or 300 t / m (denoted T3) corresponding to a twist factor K3 varying from 180 to 215 with 3 or 4 strands, And in the direction D2 (S direction). According to the invention, each of these strands is pre-manufactured by twisting three spare strands and assembling them in the twisted T2 (optionally from 110 t / m to 240 t / m) and in the opposite direction D1 (Z direction). Each of these spare strands was pre-made by a twist T1 (from 40 t / m to 120 t / m depending on the case) in the direction D1 (Z direction) relative to the yarn itself. .

  In the case of the three comparative examples C2, C4 and C6 of the cord (noted “C”) not according to the invention, these are all characterized by a triple twisted T1, T2, T3 structure. These were made exactly the same as the cords according to the invention, the only difference being that the all nylon yarns constituting these cords have an initial modulus Mi significantly lower than 800 cN / tex. That is to say.

  From the detailed examination of Table 1, first, in the case of tests 1 to 3, which were all performed using nylon yarn (initial elastic modulus of about 440 cN / tex), double twist (C1, C3 and C5) to triple twist It is noted that switching to (C2, C4 and C6) does not involve any appreciable changes to the breaking strength or other properties (Φ and yarn count).

In contrast, tests from tests 4 performed with yarns having an initial modulus Mi higher than 800 cN / tex, more particularly rayon yarn (approximately 1000 cN / tex Mi) or aramid yarn (approximately 4000 cN / tex Mi) For cases up to 6, switching from a double twisted structure (C7, C9 and C12) to a triple twisted structure (C8, C10, C11 and C13) unexpectedly without changing all other parameters With the following:
An improvement of at least 5% in breaking strength, which is very significant for the person skilled in the art.
-Together, the perceived reduction in apparent diameter Φ and yarn count. These are a better indication of the cord according to the invention, and ultimately the quality of the reinforcement, due to its highly specific structure.
-All this ultimately results in an improvement of more than 10% in apparent tenacity.
-In the case of the code C13 according to the invention, the improvement of the breaking strength and the apparent tenacity can exceed 15% and 25%, respectively.

  Two further different textile cords C14 based on the above test, in this case based on PEN type polyester (P) (“A701” by Honeywell, a yarn count 110 tex yarn with an initial modulus of approximately 1700 cN / tex). Supplemented by additional tests (Test 7 in Table 1) conducted against (Control) and C15 (Invention).

  Similar to the structure annotated above, the structure represented by “P110 / − / 3−2” for control cord C14 is that this cord is simply a twisting operation of two different strands (260 t / m T2 , D2 or S), a double twist (T1, T2) cord, each of the different strands individually twisting three polyester (P) yarns with yarn count 110tex (260t) / M of T1, D1 or Z).

  For comparison, in the case of the structure represented by “P110 / 1/3/2” of the cord C15 according to the present invention, the textile cord has a final twisting operation of two different strands (260 t / m T3, D2 or S) is a triple twist (T1, T2, T3) cord derived from, each of the different strands being subjected to an intermediate twisting operation (155 t / m T2) in the reverse direction (D1 or Z) of three spare strands Each pre-strand is made of one single polyester (P) yarn with yarn count 110 tex, which is pre-fabricated in the same direction D1 (Z). It was itself twisted during the twisting operation T1 (105 t / m).

  The results obtained are added to Table 1. These confirm the superiority of the cord C15 of the present invention with an increase in fracture strength of approximately 5% and an apparent tenacity improvement of 10% compared to the control cord C14, with a reduction in apparent diameter and yarn count. .

In conclusion, the present invention now makes it possible to improve the density, fracture strength and tenacity properties of textile cords for a given material and a given final twist, in order to reinforce the tire. Therefore, the structure of the tire is further optimized.

5: Yarn 10, 10a, 10b, 10c: Preliminary strands 20a, 20b, 20c, 20d: Strand 30, 50: Textile cord with triple twist 40: Textile cord with double twist 100: Tire 102: Crown 103: Side Wall 104: Bead 105: Bead wire 106: Crown reinforcing body or belt 107: Carcass reinforcing body 108: Folded portion 109: Rim T1, T2, T3: Twist D1, D2: Direction

Claims (22)

  Textile cord (30, 50) having at least a triple twist (T1, T2, T3) and at least N strands (20, 20a, 20b, 20c, 20d) twisted together in twist T3 and direction D2 N is greater than 1, and each strand is itself twisted T2 (T2a, T2b, T2c, T2d) and M spare strands (10, 10) twisted together in the direction D1 opposite to D2. 10a, 10b, 10c), M is greater than 1 and each spare strand itself consists of a yarn (5) that has been pre-twisted T1 (T1a, T1b, T1c) and twisted in direction D1 in advance. , Wherein at least half of the N × M yarns have an initial modulus of elasticity, expressed as Mi, greater than 800 cN / tex.   2. Code according to claim 1, characterized in that N varies from 2 to 6, preferably from 2 to 4.   3. A cord according to any one of claims 1-2, characterized in that M varies from 2 to 6, preferably from 2 to 4.   4. A cord according to any one of the preceding claims, characterized in that the total number of N x M yarns is in the range from 4 to 25, preferably from 4 to 16.   5. Cord according to any one of claims 1 to 4, characterized in that the twist T1 expressed in revolutions per meter is comprised between 10 and 350, preferably between 20 and 200.   6. Cord according to any one of the preceding claims, characterized in that each spare strand has a twist coefficient K1 comprised between 2 and 80, preferably between 6 and 70.   7. Cord according to any one of the preceding claims, characterized in that the twist T2 expressed in revolutions per meter is comprised between 25 and 470, preferably 35 and 400.   Cord according to any of the preceding claims, characterized in that each strand has a twist coefficient K2 comprised between 10 and 150, preferably between 20 and 130.   9. Cord according to any one of the preceding claims, characterized in that the twist T3 expressed in meters per revolution is comprised between 30 and 600, preferably between 80 and 500.   10. Cord according to any one of the preceding claims, characterized in that it has a twist coefficient K3 comprised between 50 and 500, preferably between 80 and 230.   The cord according to any one of claims 1 to 10, wherein T2 is larger than T1.   The cord according to any one of claims 1 to 11, wherein T3 is larger than T2.   Code according to claim 12, characterized in that T2 is comprised between 0.2 and 0.95 times T3, preferably between 0.4 and 0.8 times T3. .   The sum T1 + T2 is comprised between 0.8 and 1.2 times T3, preferably between 0.9 and 1.1 times T3. 14. The code according to any one of 13.   15. Code according to claim 14, characterized in that the sum T1 + T2 is equal to T3.   The cord according to any one of claims 1 to 15, wherein all of the N x M yarns have an elastic modulus Mi higher than 800 cN / tex.   17. Cord according to any one of the preceding claims, characterized in that at least half of the N x M yarns have an elastic modulus Mi higher than 1000 cN / tex.   18. Cord according to claim 17, characterized in that all of the N x M yarns have a modulus of elasticity Mi higher than 1000 cN / tex, preferably higher than 1200 cN / tex.   Use of a cord according to any of claims 1 to 18 for reinforcing plastic or rubber articles or semi-finished products.   An article or semi-finished product made of plastic or rubber reinforced with the cord according to any one of claims 1 to 18.   Use of the cord according to any one of claims 1 to 18 for reinforcing a tire.   A tire reinforced with the cord according to any one of claims 1 to 18.

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