DE102017217597A1 - Reinforcement member for a reinforcement layer - Google Patents

Abstract

Strength support (20) for a reinforcing layer of an elastomeric product, preferably for a carcass (2) of a pneumatic vehicle tire, wherein the strength support (20) as a cord (20) of at least two yarns (21, 22) of natural fibers, which are end twisted together formed wherein the second yarn (22) has a fineness greater than the first yarn (21) by at most a factor of 2.0, preferably at most a factor of 1.51, particularly preferably at most a factor of 1.33. The object is to provide a more cost-effective strength member with a further good tunability of the strength and the modulus of elasticity of the reinforcement layer available. This is achieved by equaling the twist count of all the yarns (21, 22) of the cord (20) and coinciding with the twist count of the cord (20).

Description

The invention relates to a reinforcing member for a reinforcing layer of an elastomeric product, preferably for a carcass of a pneumatic vehicle tire, wherein the reinforcing member is formed as a cord of at least two yarns of natural fiber, which are end twisted together, wherein the second yarn is a maximum of a factor of 2, 0, preferably at most by a factor of 1.51, more preferably at most by a factor of 1.33, greater fineness than the first yarn. The invention further relates to a reinforcement layer and a pneumatic vehicle tire having such a reinforcement.

In the context of the present invention, a "yarn" is based on DIN 60900 and is a line-shaped structure which comprises a plurality of individual filaments, i. Continuous fibers, or fibers, i. Fibers of finite length. The filaments or fibers of the yarn may be twisted together. In the context of the present invention, "cords" represent linear formations which have two or more yarns twisted end to end together. A yarn of natural fibers has natural fibers. Preferably, all filaments or fibers of the yarn are formed from natural fibers. Natural fibers are non-petroleum based textile fibers or filaments. A fiber or a filament of a material is wholly or partly formed from this material.

The "fineness" of a yarn or cord is a measure of its weight per length. The total fineness of the cord indicates the sum of the finenesses of the yarns of the cord. The fineness of a yarn may be the nominal fineness of the yarn, i. the fineness as commercially specified by the manufacturer. The actual fineness of the respective yarn may deviate from the nominal fineness due to production.

A radial type pneumatic vehicle tire generally has an air-impermeable inner layer, a radial carcass containing strength carriers, which extends from the zenith region of the tire over the side walls to the bead region and is usually anchored there by wrapping tensile bead cores, a profiled tread radially outwardly, and between the tread and the carcass arranged on belt, which is radially outwardly covered with the belt bandage. The belt bandage may be formed in one or more layers and usually covers at least the belt edges. The belt bandage typically includes parallel and substantially circumferentially extending strength members embedded in rubber. On a side of the carcass facing away from the bead core, at least one bead reinforcement having a reinforcement layer may be provided in the bead region.

Such reinforcement layers of pneumatic vehicle tires, in particular for the carcass and / or the belt bandage and / or the bead area and / or the belt, are known to the person skilled in construction and material in a wide variety of designs. The reinforcements are embedded, for example by calendering, in a rubber mixture in order to be able to be used as a rubberized reinforcement layer in the pneumatic vehicle tire.

In passenger car radial tires, the strength members of the mostly single-ply carcass run largely in the radial direction. The strength members of a reinforcement layer of the carcass must have sufficient strength to be able to absorb the forces occurring during operation of the tire sufficiently and to be durable. In particular, the carcass provides resistance to the internal pressure of the tire and has the function of a strength carrier. The largely radial course of the reinforcements increases the strength properties of the layer and improves the load-bearing capacity and the comfort features of the tire such as compression and handling. The driving behavior is additionally positively influenced, in particular in high-speed use, by a high modulus of elasticity in the case of strains of up to approx. 2% to 4% of the reinforcement of the carcass. In addition, a reinforcing layer for the carcass in tire production should allow a sufficient elevation in tire building as well as in the vulcanization mold, so that the tire can be precisely formed. In addition, the reinforcing cords should have a high breaking strength and a high elongation at break, in order to increase the fatigue life of the tire and to have an improved durability with respect to imposed elongation, as may occur, for example, when driving through a pothole.

As a material for the carcass strength carriers, it is known to use rayon cords, since rayon has a higher modulus of elasticity at 3% to 4% elongation compared to polyethylene terephthalate (PET). Common is the use of cords of 2 to 3 yarns of the same fineness. As a rule, yarns with certain commercially available fineness values are generally available on the market. Commercially available fineness values for rayon yarns are, for example, 1220 dtex and 1840 dtex. Although subtleties deviating from these commercially available fineness values can be produced, they are cost-intensive in purchasing due to their low market availability. If a firmer reinforcement layer is required, this is adjusted by means of the thread density in the reinforcement layer or yarns of the next higher commercially available fineness value are used. A higher one However, thread density in the reinforcement can lead to less mixing between the cords and thus bring disadvantages in durability and rolling resistance. A higher fineness, however, often increases the layer thickness too much, which also brings disadvantages in rolling resistance.

From the DE 195 14 096 A1 is known as strength carrier of the carcass a cord of the construction Rayon 1220x1 + 1840x1. The cord is thus made of a first yarn of rayon of fineness 1220 dtex and a second yarn of rayon of fineness 1840 dtex. This provides a cord whose overall fineness of 3060 dtex is between the total fineness of a cord made up of two yarns of fineness 2440 dtex and the total fineness of a cord made of two yarns of fineness 3680 dtex. However, the first smaller denier yarn has a larger twist count than the second yarn. In this way, the formation of a so-called. False wire is to be avoided, which is feared by the expert in the twisting of yarns of different fineness to a cord. However, such a procedure with different numbers of twists is complicated and cost-intensive.

The object of the present invention is to provide a more cost-effective reinforcement with a further good tunability of the strength and the modulus of elasticity of the reinforcement layer.

The problem is solved by equaling the twist count of all yarns of the cord and matching the twist count of the cord. The yarns thus have a twist count and the cord has a twist count. The twist counts of the yarns coincide with the twist count of the cord. A twisting number indicates with how many revolutions per meter the fibers or filaments of the yarn are (first) twisted with each other or with how many revolutions per meter the yarns of the cord are end-twisted together.

Surprisingly, it has been found that with a cord having two yarns of natural fibers, the fineness of at most a factor of 2.0, preferably at most by a factor of 1.51, more preferably at most by a factor of 1.33, different, the same Twist number of yarns and cord leads to no relevant drawbacks. Since the subtleties of the two yarns differ only slightly from each other, the cords with the said symmetrical twist have only a small residual stress. An elastomeric reinforcement layer provided with such cords as reinforcement can be used excellently as a reinforcement layer for elastomeric products, preferably for a carcass of a pneumatic vehicle tire.

In addition, the said cords are inexpensive to produce, since this is possible with a low-cost one-step process on so-called direct cuvettes. Initially, the yarns used for the cord with a certain twisting number x are pre-twisted in one direction and subsequently the yarns, as a rule 2 or 3 , with the identical number of turns x End-turned in the opposite direction to the reinforcing cord. Either all the yarns are in S Direction twisted and in with each other Z Direction twisted to the cord. Or all the yarns are in there Z Direction twisted and in with each other S Direction twisted to the cord. This results in a strength carrier in which the individual yarns then no longer have rotation, since they were turned back.

The fine tuning of the total fineness of the cords as well as the strength and the modulus of elasticity of a reinforcement layer can thus continue to be made over the total fineness of the cords. Especially for a reinforcement layer of the carcass, a precise adjustability of the strength and the modulus of elasticity is advantageous. An adverse strong increase in the thread density or a strong increase in the layer thickness is no longer necessary. It is essential here that cost-effective yarns with customary fineness values can continue to be used.

As a result, a more cost-effective strength member with a further good tunability of the strength and the modulus of elasticity of the reinforcement layer is provided.

It is expedient if the cord has exactly the first yarn and the second yarn.

In a preferred embodiment, the natural fibers are natural fibers of viscose, preferably of rayon or lyocell, more preferably of rayon. Preferably, it is rayon yarns that are twisted end to end. Cords comprising a rayon yarn are excellently suited as reinforcements of the carcass.

In a preferred embodiment, the fineness of the first yarn is at most 620 dtex, preferably at most 600 dtex less than the fineness of the second yarn. It is expedient if the fineness of the first yarn and the fineness of the second yarn differ by at least 50 dtex and / or by a factor of at least 1.05. With a smaller difference in the fineness of the yarns, the change in the properties of a reinforcement layer can usually be changed by only a slight change be achieved in the thread density without significant disadvantages.

Advantageous reinforcement layers are in particular made possible when the fineness of the first yarn is 610 dtex to 2440 dtex. For smaller finenesses, the low residual stress of the cord can lead to a corrugation at cut ends of the reinforcement layer.

Commercially available fineness values for rayon yarns may be selected from the group formed from 610 dtex, 1220 dtex, 1840 dtex, 2440 dtex, 3680 dtex. Yarns from this group generally have good market availability. It is advantageous if the first yarn and / or the second yarn is a rayon yarn and has a commercial fineness value.

Concrete cord structures made of rayon yarns having commercial fineness values are given, for example, by: 610x1 + 1220x1, 1220x1 + 1840x1, 1840x1 + 2440x1, 2440x1 + 3680x1.

In a preferred embodiment, the twist factor α of the cord is 180 to 310, preferably 200 to 290, particularly preferably 220 to 270. The twist factor α is defined as α = twist count [T / m] * (fineness [tex] / 1000) ^1/2 . The number of turns is given in revolutions per meter (turns per meter). The fineness refers to the total fineness of the cord, ie the sum of the finenesses of the yarns of the cord. A strength member having such a twist factor is characterized by a force-elongation behavior which, when using the reinforcement layer, in particular as a carcass ply in pneumatic vehicle tires, permits problem-free tire construction including vulcanization and gives the tire advantageous durability.

To ensure reliable adhesion of the cord to the elastomeric material, it is advantageous to coat the yarns and / or the cord with an adhesive impregnation, e.g. with an RFL dip in 1-bath or 2-bath process.

The invention also relates to a reinforcement layer for elastomeric products, in particular for pneumatic vehicle tires, comprising at least one cord according to the invention. The reinforcements are usually arranged in such a reinforcement layer parallel to each other and embedded in elastomeric material.

The reinforcing layer can be used in different elastomeric products, e.g. in hoses, drive belts, conveyor belts, blankets or air springs. Preferably, however, the reinforcement layer is used for pneumatic vehicle tires. A reinforcement layer of a pneumatic vehicle tire having at least one such reinforcement can be adapted very precisely to the required properties such as strength and modulus of elasticity by the selected finenesses of the yarns. At the same time, the reinforcement layer comprising the symmetrically twisted cords of at least two natural fiber yarns is less expensive to produce. This may be a reinforcement layer of the belt bandage and / or a reinforcement layer of the carcass and / or a reinforcement layer of the bead reinforcement. Particularly preferred is a reinforcement layer of the carcass. Here, the advantages of the cord made of rayon yarns have a particularly advantageous effect. One or two or all of the reinforcement layers of the carcass can be designed according to the invention.

The invention further relates to a pneumatic vehicle tire having such a reinforcement layer. The pneumatic vehicle tire preferably has a carcass ply according to the invention. The cords can be used as reinforcement of reinforcement layers for tires for passenger cars, for van, for light trucks, for motorcycles as well as for commercial vehicles or buses.

• 1 einen radialen Querschnitt durch einen erfindungsgemäßen Fahrzeugluftreifen;
• 2 einen Kord einer Festigkeitsträgerlage gemäß der Erfindung.

Further features, advantages and details of the invention will now be explained in more detail with reference to the schematic drawings which illustrate exemplary embodiments. It shows the

• 1 a radial cross section through a pneumatic vehicle tire according to the invention;
• 2 a cord of a reinforcement layer according to the invention.

The 1 shows a radial cross section through a pneumatic vehicle tire for a passenger car. The essential components of which the illustrated pneumatic vehicle tire is composed are a largely air-impermeable inner layer 1 , here is a reinforcement layer 9 comprehensive carcass 2 in a conventional manner from the zenith of the pneumatic vehicle tire over the side walls 3 to the bead areas 4 ranges and there by wrap tight tensile bead cores 5 is anchored, located radially outside the carcass profiled tread 6 and one between the tread 6 and the carcass 2 arranged containing belt 7 , which radially outward with the here a reinforcement layer 9 comprehensive belt bandage 8th is covered. The pneumatic vehicle tire can be in the bead area 4 a reinforcement layer 9 to reinforce the bead area 4 have (in the 1 not shown).

For pneumatic vehicle tires in as in 1 shown radial design are the strength carrier of a reinforcement layer 9 the carcass 2 arranged approximately parallel to each other approximately in the radial direction. The reinforcement layer 9 the belt bandage 8th includes one or more strength members that are or are continuously wound along the axial width.

The illustrated pneumatic vehicle tire can be a reinforcement layer according to the invention 9 the carcass 2 exhibit. The strength members are arranged substantially parallel to each other within the reinforcement layer and embedded in elastomeric material. At least one reinforcement is designed as a cord of at least two yarns of natural fibers. The at least two yarns are twisted together. The second yarn 22 has a fineness which is greater than the fineness of the first yarn by at most a factor of 2.00, preferably by at most a factor of 1.51, particularly preferably by at most a factor of 1.33 21 , Next is the twist count of all yarns 21 . 22 of the cord 20 equal and agrees with the twist count of the cord 20 match.

Also or alternatively, one or more reinforcing layers of the belt bandage 8th and / or a reinforcement layer of the bead reinforcement in the bead area 4 be carried out according to the invention.

The 2 shows a cord 20 for a reinforcement layer 9 according to the invention. It can be a cord 20 for one in the 1 shown reinforcement layer 9 act. The cord 20 is particularly suitable for a reinforcement layer 9 a carcass 2 , The cord is made of two yarns 21 . 22 made of natural fibers, which are end twisted together. The at least two yarns 21 . 22 are twisted together. The ratio of the fineness of the second yarn 22 to the fineness of the first yarn 21 can be at most 2.00, preferably at most 1.51, particularly preferably at most 1.33. Both yarns 21 . 22 and the cord 20 have the same number of twists. Both yarns 21 . 22 have the same direction of rotation. The cord 20 has the opposite direction of rotation.

The first yarn 21 may have a fineness which is less than the fineness of the second yarn by at most 620 dtex, preferably at most 600 dtex 22 , The natural fiber may be a natural fiber of viscose, preferably of rayon or lyocell. For a reinforcement of a carcass 2 is particularly suitable rayon. The fineness of the first yarn can be 610 dtex to 2440 dtex. The cord can be a cord of two yarns of rayon construction 610x1 + 1220x1, 1220x1 + 1840x1, 1840x1 + 2440x1 or 2440x1 + 3680x1. Such cords are excellent for reinforcing the carcass. For better adhesion of the cords 20 to the elastomeric material, the cords 20 be provided with an adhesive impregnation.

LIST OF REFERENCE NUMBERS

1

Innenschicht

2

Karkasse

3

Seitenwand

4

Wulstbereich

5

Wulstkern

6

Laufstreifen

7

Gürtel

8

Gürtelbandage

9

Festigkeitsträgerlage

20

Kord

21

erstes Garn

22

zweites Garn

(Part of the description)

1

inner layer

2

carcass

3

Side wall

4

bead

5

bead

6

tread

7

belt

8th

belt bandage

9

Reinforcement layer

20

cord

21

first yarn

22

second yarn

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19514096 A1 [0008]

Claims (8)

Strength support (20) for a reinforcing layer of an elastomeric product, preferably for a carcass (2) of a pneumatic vehicle tire, wherein the reinforcing member (20) as a cord (20) of at least two yarns (21, 22) of natural fibers, which are end twisted together formed wherein the second yarn (22) has a fineness higher than the first yarn (21) by at most a factor of 2.0, preferably at most a factor of 1.51, particularly preferably at most a factor of 1.33 in that the twist count of all the yarns (21, 22) of the cord (20) is the same and coincides with the twisting number of the cord (20). Reinforcement (20) after Claim 1 , characterized in that the natural fibers are natural fibers of viscose, preferably of rayon or lyocell, more preferably of rayon. Reinforcing member (20) according to one or more of the preceding claims, characterized in that the fineness of the first yarn (21) is at most 620 dtex, preferably at most 600 dtex, smaller than the fineness of the second yarn (22). Reinforcing member (20) according to one or more of the preceding claims, characterized in that the first yarn (21) has a fineness of 610 dtex to 2440 dtex. Reinforcing member (20) according to one or more of the preceding claims, characterized in that the first yarn (21) and / or the second yarn (22) is formed of rayon and has a commercial Feinheitswert. Reinforcing member (20) according to one or more of the preceding claims, characterized in that the twist factor of the cord (20) is 180 to 310, preferably 200 to 290, particularly preferably 220 to 270. Reinforcing layer (9) for elastomeric products, in particular for pneumatic vehicle tires, comprising at least one strength support (20) according to one or more of the preceding claims. Vehicle pneumatic tire having at least one reinforcement layer (9) after Claim 7 ,

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