JP6778191B2 - Textile cord with at least triple twist - Google Patents

Description

The present invention relates to textile reinforcing elements or "reinforcing materials" that can be used to reinforce plastic articles or rubber articles such as vehicle tires.

More specifically, the present invention relates to textile cords or twisted yarns, which can be used specifically to reinforce such tires.

Textiles have been used as a reinforcement since the first appearance of tires.

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 even in high performance tires certified for ultra-high speed travel. To meet the requirements of the tires, they have high breaking strength, high modulus, excellent fatigue durability and, finally, excellent against rubber or other polymer matrices that will be reinforced. It is necessary to have adhesiveness.

It can be easily recalled here that these textile twisted yarns or cords are traditionally double twisted (T1, T2) type and are made by a method known as the twisting method. In the method
-During the first step, each multifilament fiber or yarn that makes up the final cord is first individually in a given direction D1 (in the S or Z direction, respectively) by itself (at the initial twist T1). It is twisted to form a strand, within which the element filaments are spirally deformed around the axis of the fiber (or the axis of the strand).
-Then, during the second step, some strands, generally a few or four strands, which have the same properties or different properties in the case of a cord called hybrid or composite, are then finally twisted. At T2 (which may or may not be the same as T1), opposite direction D2 (Z direction or S direction, respectively, according to the approved naming convention for the direction of rotation according to the diagonal line of S or Z). Twisted together to give a cord or final assembly containing several strands.

The purpose of twisting is to adapt the properties of the material in order to generate a cohesive force in the transverse direction of the reinforcing material, enhance its fatigue durability and also improve its adhesion to the reinforced matrix.

Such textile codes, their structures and manufacturing methods are known to those skilled in the art. These are a large number of 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 Document 1, even if only a few examples are given. It 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 European Patent No. 220642 European Patent No. 225391 European Patent No. 335588 European Patent No. 467585 U.S. Pat. No. 3,419,060 U.S. Pat. No. 3,977,172 U.S. Pat. No. 4,155,394 U.S. 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

Fatigue strength (tensile, bending, compressive durability) of these textile cords is an important key in making it possible to reinforce rubber articles such as tires. 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 in terms of unit weight). ) Is known to inevitably decrease as the twist increases, which is naturally disadvantageous from the viewpoint of reinforcement.

As such, textile code designers such as tire manufacturers are constantly searching for textile codes that can improve mechanical properties, especially breaking loads and tenacity, for a given material and given twist. There is.

Currently, in the course of the study, Applicants are able to unexpectedly improve the breaking load and tenacity properties for a given material and given final twist due to the specific composition and structure. I found a concrete new textile code to make.

Therefore, according to the first subject, the present invention relates to at least triple twisted (T1, T2, T3) textile cords, the textile cord having at least N strands twisted together in twist T3 and direction D2. Containing, 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 T2 and D2, where M is greater than 1. Each spare strand itself consists of yarns that are pre-twisted T1 and twisted in direction D1, and at least half of the N × M yarns are higher than 800 cN / tex, the initial modulus represented by Mi. Have a rate.

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

The tires of the present invention can be specifically intended for passenger cars, 4x4, or SUB (sports utility vehicle) type vehicles, but for two-wheeled vehicles such as motorbikes, or vans, heavy-duty vehicles, etc. That is, it is intended for subway vehicles, buses, road transport vehicles (trucks, tractors, trailers) and off-road vehicles, agricultural or civil engineering equipment, aircraft, and industrial vehicles selected from other transport or work vehicles. You can also.

More specifically, the textile cord of the present invention is intended to be used in a crown reinforcing body (or belt) or a carcass reinforcing body of the tire for the vehicle.

The present invention and its advantages are described in detail and subsequent exemplary embodiments, as well as from FIG. 1 relating to these embodiments (not drawn to a particular scale unless otherwise indicated). It will be easily recognized in view of FIG. 7.

First, the initial state (5) of the conventional multifilament textile fiber (or yarn), that is, the untwisted state, is shown, and then the yarn that is itself twisted, that is, the "preliminary strand" (10). It is sectional drawing which shows after the 1st twist operation T1 of the direction D1 for forming. Preliminary strands (previously in the same direction D1 in T1a, T1b, T1c) assembled by a second twisting operation T2 in the same direction D1 for the formation of the strand (20) intended for the cord according to the invention. It is sectional drawing which shows the assembly of three yarns (10a, 10b, 10c) as described above which functions as (twisted in). The above, which was assembled by a third twisting operation T3 in the direction D2 opposite to the direction D1 this time for the formation of the final textile cord (30) with triple twists (T1, T2, T3) according to the present invention. It is sectional drawing which shows the assembly of three strands (20a, 20b, 20c) (previously twisted in the same direction D1 in T2a, T2b, T2c). Assembled by a second twisting operation T2 in the direction D2 opposite to the direction D1 for the formation of the textile cord (40) by the prior art with double twists (T1, T2), this time directly strands. FIG. 5 is a cross-sectional view showing a conventional assembly of the three yarns (10a, 10b, 10c) as described above, which function as (all pre-twisted in direction D1 at T1a, T1b, T1c). Assembled by a third twisting operation T3 in the direction D2 opposite to the direction D1 for the formation of the final textile cord (50) with triple twists (T1, T2, T3) according to the present invention (previously T2a). , T2b, T2c, T2d, twisted in the same direction D1) 4 strands (20a, 20b, 20c, 20d) showing an assembly. Once formed, the final cross section of the textile cord under minimal tension (whether it is according to the present invention or not) is a high degree of lateral plasticity provided by the multifilamental nature of the starting material. Therefore, it is a cross-sectional view that is less schematic than the previously shown figure of code (50) above, 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 a plane including the rotation axis of the tire) showing an example of the tire according to the invention incorporating the textile code according to the invention.

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

The interval between values represented by the expression "between a and b" represents the range of values ranging from values greater than a to values less than b (ie, endpoints a and b are excluded), while "between endpoints a and b". The interval between values represented by the expression "a to b" means a range of values extending from a to b (that is, strictly including the endpoints a and b).

Therefore, the textile cord or twist yarn of the present invention is a textile code (30, 50) having a highly specific structure (see Attachments 1 to 3 and FIG. 5), which are described below. It has essential features including.
-At least triple (which means more than 3 or 3) twists (T1, T2, T3).
-At least N strands (20, 20a, 20b, 20c, 20d) twisted together in the final twist T3 and the final direction D2, where N is greater than 1.
-Each strand is an M spare strand (10, 10a, 10b, 10c) that itself is twisted together in the intermediate twist T2 (T2a, T2b, T2c, T2d) and in the direction D1 opposite to D2. It is configured and M is greater than 1.
-Each spare strand consists of yarns (5) that are pre-twisted in their own initial twist T1 (T1a, T1b, T1c) and in the initial direction D1.

Those skilled in the art can "disassemble" the cords of the present invention and "return" them to the initial yarns that compose them, from the expression cord having at least triple twists (which means having three or more twists). Immediately, at least three consecutive untwisting (or opposite twisting) operations are required to re-find the initial state, i.e. the untwisted starting yarn (multifilament fiber). Will understand. In other words, forming the cord of the present invention involves at least three (three or more) sequential twisting operations, rather than two as usual.

Another essential feature is that at least half of the yarns that make up the cord must have an initial modulus Mi higher than 800 cN / tex (which excludes nylon fibers in particular), 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 are described in detail here.

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

After the twisting operation T1 (first twist) in direction D1 (S or Z), the initial yarn (5) is converted to a yarn known as a "preliminary strand" (10), which is itself twisted. To. Therefore, within this spare strand, the element filament is in a state of being spirally deformed around the axis of the fiber (or the axis of the spare strand).

Then, as shown in FIG. 2 as an example, M spare strands (for example, three of them, 10a, 10b, 10c) are then placed in the same direction D1 as before, with an intermediate twist T2 (second). Twisting) itself is twisted together to form a "strand" (20). Each spare strand is characterized by a particular first twist T1 (eg, here T1a, T1b, T1c), which may be equal (generally, ie here eg T1a = T1b = T1c). Yes, or may differ from each other for each spare strand.

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

Thus, the final textile cord (30) thus obtained, including N × M (here, eg, 9) spare strands, is characterized by (at least) triple twists (T1, T2, T3).

The present invention, of course, gives the starting yarn (5) more than three sequential twists, eg, four (T1, T2, T3, T4) or five (T1, T2, T3, T4, T5). It also applies when it is. However, the present invention is preferably carried out in just 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. The M spare strands (eg, here three strands 10a, 10b, 10c) actually act directly as strands, which are opposite to the (first) twist direction D1 (first). They are twisted together in direction D2 (2) to directly form a conventional double twisted (T1, T2) textile cord (40).

FIG. 5 schematically shows a cross section of an assembly of four strands (20a, 20b, 20c, 20d) (previously twisted in the same direction D1 at T2a, T2b, T2c, T2d). Assembled by a third twisting operation T3 in the direction D2 opposite to the direction D1 to form another example of the final cord (50) having triple twists (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 from strand to strand.

As a precaution, FIG. 6 also shows another diagram of the above cord (50), which is less schematic than the one shown above, in cross section, and is a cross section of the textile cord once formed under minimal tension. By the way, whether it is according to the present invention or not, the strands (20a, 20b, 20c, 20d) and the spare strands (10a, 10b, which are provided by the multifilamental properties of the strand fibers (yarns). Recall the well-known fact that due to the high degree of lateral radial plasticity in 10c), it actually approaches a cylindrical structure with an essentially circular contour.

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

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, but the present invention is a polymeric material 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 as PVA), polyketone, aramid (aromatic polyamide), aromatic polyester, polybenzazole (abbreviated as PBO), polyimide, Polyesters, especially 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 states that when the textile cords of the present invention are formed of several yarns of different materials in order to construct hybrid or composite yarns, for example, at least polyester and nylon, 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 (eg PET or PEN), and even aramid. Applicable when based on polyketone yarns, at least half of N × M yarns, of course, have an elastic ratio Mi higher than 800 cN / tex.

In the code of the present invention, N varies preferably in the range of 2 to 6, more preferably in the range of 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) falls within the range of 4 to 25, more preferably 4 to 16.

In a manner well known to those skilled in the art, twisting can be measured and expressed in two different ways, i.e., in the simplified method, expressed in revolutions per meter (t / m) or with different properties (cubic density). ) And / or if you wish to compare materials with different yarn counts, they are more precisely expressed in the form of a twist coefficient K, by or equivalent to the twist angle of the filament. The twist coefficient K is related to the twist T (here, for example, T1, T2 and T3, respectively) by the following known relationships.
K = (twisted T) x [(yarn count / (1000 ・ ρ)] ^1/2
Here, the twist T of the element filament (constituting the spare strand, strand or twist yarn) is represented by rotation per meter (t / m), and the yarn count is tex (spare strand, strand or twist yarn 1000). Represented in grams of weight in meters), and finally, ρ is the density or cubic density (g / cm ³ ) of the material that makes up the reserve strands, strands or twisted yarns (eg, about 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, it is the average density weighted by the respective yarn counts of the materials that make up the reserve strands, strands or twisted yarns.

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

According to another preferred embodiment, the twist T2, represented per meter of revolution, is preferably between 25 and 470, more preferably between 35 and 400. According to another preferred embodiment, each strand has a twist factor K2 contained between 10 and 150, more preferably between 20 and 130.

According to another preferred embodiment, the twist T3, represented per meter of revolution, is preferably 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 contained between 50 and 500, more preferably between 80 and 230.

Preferably, T2 is greater than T1 (T1 and T2 are particularly represented by t / m). According to another preferred embodiment, which may or may not be combined with said embodiment, T2 is less than T3 (T2 and T3 are particularly represented by t / m) and T2 is more preferably T3. It is included between 0.2 times and 0.95 times of T3, especially between 0.4 times and 0.8 times of T3.

According to another embodiment, the sum T1 + T2 is contained between 0.8 times and 1.2 times T3, more preferably 0.9 times and 1.1 times T3 (T1, T2 and T3 are particularly represented by t / m), and T1 + T2 is specifically equal to T3.

In the cords of the present invention, preferably the majority (number basis) of N × M yarns, more preferably all (in the initial state, i.e. untwisted), are higher than 800 cN / tex. In particular, it has an elastic modulus Mi higher than 1000 cN / tex. The initial modulus Mi or Young's modulus is, of course, the modulus in the longitudinal direction, that is, the modulus along the axis of the yarn.

Even more preferably, at least half of the N × M yarns, especially most (number-based), 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 Mi higher than 1000 cN / tex, particularly higher than 1200 cN / tex, more specifically higher than 1400 cN / tex.

All properties shown above (yarn count, initial modulus of yarn, fracture strength and tenacity) are pre-conditioned, bare (which means uncoated) or coated cord (which is used). It is determined at 20 ° C. for a cord that is ready to be used, or a cord taken from its reinforced article). "Pre-conditioning" means storing the cord (after drying) at least 24 hours in a standard atmosphere (temperature 20 ± 2 ° C, relative humidity 65 ± 2%) according to the European standard DIN EN 20139 before measurement. To do.

The yarn count (or linear density) of the spare strand, strand or cord is determined by weighing this length against at least three samples, each corresponding to a length of at least 5 m, and the yarn count is tex. (Note that 0.111 tex is equal to 1 denier) given in a gram weight of 1000 m of product.

Tensile mechanical properties (tenacity, initial modulus, elongation at break) are "4D" type (for breaking strength less than 100 daN) or "4E" type according to standard ASTM D885 (2010) unless otherwise specified. Measured by known methods using an ASTM ON tensile tester equipped with a capstan grip (for fracture strength equal to at least 100 daN). The test piece receives traction at a nominal speed of 200 mm / min under a standard preliminary tension of 0.5 cN / tex over an initial length of 400 mm for a 4D grip and 800 mm for a 4E grip. All the results obtained are the average of 10 measurements. When measuring the properties of yarns, the yarns are, in a well-known manner, a very light pre-twist corresponding to a twist angle of about 6 degrees, before being placed in the grip and tensioned. receive.

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

The textile cords of the present invention advantageously provide tires for all types of vehicles, especially motorbikes, passenger cars, or industrial vehicles such as heavy duty vehicles, construction plant vehicles, aircraft, and other transport or work vehicles. Can be used to reinforce.

As an example, FIG. 7 shows a fairly schematic (regardless of scale) radial cross section of a tire according to the invention, for example for a passenger car type vehicle.

The tire 100 includes a crown 102 reinforced by a crown reinforced body or belt 106, a sidewall 103, and two beads 104, each of which is reinforced by a bead wire 105. A tread (not shown in this schematic diagram) is placed on the crown 102. A carcass reinforcement 107 is wrapped around two bead wires within each bead, and the folded portion 108 of the reinforcement 107 is, for example, the outside of the tire 100 depicted here attached to its rim 109. It 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, which means that these cords are virtually parallel to each other. 80 ° and 90 ° with respect to the circumferential center plane (the plane that is placed between the two beads 104 and passes through the center of the crown reinforcement 106 and is perpendicular to the tire rotation axis). It means extending from one bead to the other so as to form an angle between them.

The belt 106 is composed of at least two rubber plies, for example, in a manner known per se, called "working plies" or "triangulation plies", which are superposed, intersecting and substantially. Arranged parallel to each other and reinforced with metal cords inclined with respect to the circumferential central plane, these working plies are or are not tied to other rubber plies and / or fabrics. These working plies have the main function of providing 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 reinforcing threads called "circumferential", in which those 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 preferably within the range 0 ° to 10 ° with respect to the circumferential central plane. Means that. It is recalled that these circumferential reinforcement threads have the primary function of resisting crown spin-out at high speeds.

The tire 100 of the present invention has, for example, the essential feature that at least the hopping ply of the belt (106) and / or the carcass reinforcement (107) thereof includes the textile cord according to the present invention. According to another possible exemplary embodiment of the invention, it is, for example, a bead wire (105) that is made up entirely or in part of the textile code according to the invention.

The rubber compositions used in these plies are conventional for skimming textile reinforcements, typically with natural rubber or some other diene elastomer and a reinforcement filling such as carbon black. Based on materials and vulcanized 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.

Due to its particular structure, the textile cords of the present invention have particularly improved tensile test properties, as evidenced by the following exemplary embodiments.

In these exemplary embodiments, six different tensile tests were first performed to produce 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 embodiment of the cord (“T” is control, “C] is comparative, and“ I ”is according to the invention), the material used (“N” is nylon, “R” is rayon, “A”. ”Aramid), its structure and final properties are summarized in Attached Table 1.

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

As already shown, tenacity is the breaking force against the yarn count and is expressed in cN / tex. Apparent tenacity (daN / mm ² ) is also shown, where the breaking force is for the apparent diameter represented by Φ, measured according to the following method.

Using a device that uses a receiver consisting of a condensing system, a photodiode, and an amplifier, it is possible to measure the shadow of a thread illuminated by a parallel light laser beam with an accuracy of 0.1 micrometer. Become. Such a device is commercially available, for example, by Z-Mike under part number "1210". The method comprises fixing a pre-conditioned thread test piece to be measured on an electrically movable table under a standard reserve load of 0.5 cN / tex. Once anchored to the movable table, the thread is moved perpendicular to the cast-shadow measurement system at a speed of 25 mm / sec to intersect the laser beam orthogonally. At least 200 shadow projection measurements are obtained on a 420 mm long thread, and the average of these shadow projection measurements represents the apparent diameter Φ.

For each test, the breaking load, tenacity and apparent tenacity were also shown converted to relative values with the control code in each test as 100.

All control cords (represented by "T" in Table 1) are characterized by conventional double-twisted T1, T2 structures, and all other cords (comparative examples or according to the present invention) are non-conventional triple-twisted. It is characterized by T1, T2 and T3 structures. However, only the cords according to the invention combine the characteristics of triple twist with an initial modulus of elasticity higher than 800 cN / tex.

To make this Table 1 easier to read, here, for example, for control code C1, the structure represented by "N47 / − / 3/4" is such that this code simply twists four different strands (T2). , D2 or S), each of which is a double twisted (T1, T2) cord in which three nylon (N) yarns with a yarn count of 47tex are individually twisted in opposite directions (T1). , D1 or Z), which means that it is prefabricated.

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

Six Examples of Control Codes (Represented by "T") C1, C3, C5, C7, C9 and C12 are all characterized by a double-twisted structure, which has two, three or four strands. Manufactured by assembling in a (second) final twist (represented by T2) from 150 t / m to 300 t / m corresponding to a twist factor K2 varying from 175 to 215, and in direction D2 (S direction). It is a thing. In the conventional scheme, each of these strands has a (first) initial twist (represented by T1) in the opposite direction D1 (Z direction) to the yarn itself, optionally from 150 t / m to 300 t / m. And it is manufactured in advance.

The four examples C8, C10, C11 and C13 of the codes according to the invention (represented by "I" and shown in bold in Table 1) are all triple-twisted T1, T2, T3 structures (Z / in these examples). Characterized by Z / S), these are three or four strands with a final twist (represented by T3) from 150 t / m to 300 t / m corresponding to a twist factor K3 that varies from 180 to 215. And manufactured by assembling in direction D2 (S direction). According to the present invention, each of these strands is prefabricated by twisting three spare strands and assembling them in T2 (possibly 110 t / m to 240 t / m) and opposite direction D1 (Z direction). Each of these spare strands was prefabricated by a twist T1 (possibly from 40 t / m to 120 t / m) in the direction D1 (Z direction) with respect to the yarn itself. ..

In the case of three comparative examples C2, C4 and C6 of codes not according to the invention (represented by "C"), they are all characterized by triple-twisted T1, T2, T3 structures. These were made exactly like the cords according to the invention, the only difference being that the all-nylon yarns that make up 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 performed using all nylon yarns (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 perceptible changes to fracture strength or other properties (Φ and yarn counts).

In contrast, tests from Test 4 performed with yarns with an initial modulus Mi higher than 800 cN / tex, more specifically rayon yarns (Mi of approximately 1000 cN / tex) or aramid yarns (Mi of approximately 4000 cN / tex). For 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. , Accompanied by:
-At least 5% improvement in fracture strength, which is very significant for those skilled in the art.
-In addition, the apparent diameter Φ and the yarn count are perceptible reduction. These are, due to their highly specific structure, a clear indicator of the better precision of the cords according to the invention, and ultimately the quality of the stiffeners.
-All of this ultimately results in an increase of more than 10% in apparent tenacity.
-In the case of code C13 according to the present invention, the improvement in breaking strength and apparent tenacity can exceed 15% and 25%, respectively.

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

Similar to the structure annotated above, the structure represented by "P110 // 3-2" for control cord C14 is such that this cord simply twists two different strands (T2 at 260 t / m). , D2 or S), and each of the different strands is an operation (260t) in which three polyester (P) yarns having a yarn count of 110tex are individually twisted in opposite directions. It means that it was prepared in advance by T1, D1 or Z) of / m.

By 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 is a final twisting operation of two different strands (260 t / m T3, D2 or A triple twist (T1, T2, T3) cord derived from S), each of which is a reverse (D1 or Z) intermediate twist operation (155 t / m T2) of the three spare strands. Prefabricated, each of the spare strands consists of one single polyester (P) yarn with a yarn count of 110tex, which is preliminarily added with a first addition in the same direction D1 (Z). It was itself twisted during the twisting operation T1 (105 t / m).

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

In conclusion, the present invention now makes it possible to improve the tightness, breaking strength and tenacity properties of textile cords for a given material and given final twist, in order to reinforce the tire. It can be used for, and therefore the structure of the tire is further optimized.

5: Yarns 10, 10a, 10b, 10c: Spare strands 20a, 20b, 20c, 20d: Strands 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 reinforcement or belt 107: Carcass reinforcement 108: Folded portion 109: Rim T1, T2, T3: Twist D1, D2: Direction

Claims (10)

Textile cords (30, 50) with at least triple twists (T1, T2, T3) and at least N strands (20, 20a, 20b, 20c, 20d) twisted together in twist T3 and direction D2. Including, N is greater than 1, and each strand is twisted together with T2 (T2a, T2b, T2c, T2d) and D1 in the direction opposite to D2, M spare strands (10, Consists of 10a, 10b, 10c), M is greater than 1, and each spare strand itself consists of yarns (5) that are pre-twisted T1 (T1a, T1b, T1c) and twisted in direction D1. At least half of the N × M yarns have an initial modulus represented by Mi, which is higher than 800 cN / tex, and the sum T1 + T2 is between 0.8 and 1.2 times T3. , T3 is greater than T2 rather, T2 is comprised between 0.4 times and 0.8 times the T3, and wherein the code. The code according to claim 1, wherein N varies in the range of 2 to 6. The code according to any one of claims 1 to 2, wherein M varies in the range of 2 to 6. The code according to any one of claims 1 to 3, wherein the total number of N × M yarns is included in the range of 4 to 25. The code according to any one of claims 1 to 4, wherein the twist T1 expressed in meters per revolution is included between 10 and 350. The code according to any one of claims 1 to 5, wherein the twist T2 expressed in meters per revolution is included between 25 and 470. The code according to any one of claims 1 to 6, wherein the twist T3 expressed in meters per revolution is included between 30 and 600. The code according to any one of claims 1 to 7, wherein T2 is larger than T1. A plastic or rubber article or semi-finished product reinforced with the code according to any one of claims 1 to 8. A tire reinforced with the code according to any one of claims 1 to 8.

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