DE102017217437A1 - Reinforcement member for a reinforcement layer - Google Patents

Abstract

Strength support (20) for one of an elastomeric product, preferably for a belt bandage (8) of a pneumatic vehicle tire, wherein the strength support (20) as a cord (20) of at least two yarns (21, 22) made of polyamide (PA), which are end twisted together , and wherein the first yarn (21) has a smaller fineness than the second yarn (22). The object is to provide a cost-effective reinforcement for a reinforcement layer with improved durability and with improved tunability of the strength and the modulus of elasticity of the reinforcement layer position, without having to accept disadvantages in rolling resistance. The object is achieved in that the ratio of the fineness of the second yarn (22) to the fineness of the first yarn (21) is at most 1.34, preferably at most 1.12.

Description

The invention relates to a reinforcement for a reinforcement layer of an elastomeric product, preferably for a belt bandage of a pneumatic vehicle tire, wherein the reinforcement is formed as a cord of at least two yarns of aliphatic polyamide (PA), which are end twisted together, wherein the first yarn a smaller fineness has as the second yarn. Furthermore, the invention relates to a reinforcement layer comprising such a reinforcement and a pneumatic vehicle tire having such a reinforcement layer.

A "yarn" is in the context of the present invention based on the DIN 60900 a line-shaped structure consisting of several individual filaments, ie continuous filaments. The filaments of the yarn can be twisted together. In the context of the present invention, "cords" represent linear formations consisting of two or more yarns twisted together. A yarn made of a material consists wholly or partly of filaments of 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 remote from the bead core side of the carcass, a bead reinforcement having at least one 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.

The belt bandage prevents a collection of the tire by the centrifugal forces occurring during driving, especially in high-speed deployment. The belt bandage is applied in the manufacture of tires in the form of layers, strips or individual reinforcements with embedded in an unvulcanized rubber compound reinforcing agents that are wound or wound on the belt. The reinforcing members are embedded in rubber by passing longitudinally through a calender or extruder for covering with the rubber composition a group of substantially parallel filiform reinforcing members, which are usually provided with an adhesive impregnation for better adhesion to the embedding rubber. During tire cambering and vulcanization, the tire usually rises to 2% in the shoulder area and up to 4% in the center area as compared to the unvulcanized blank when the blank is wound on a flat drum.

As a material for the reinforcements of the belt bandage, it is known to use cords made of PA 6.6, since PA 6.6 has an advantageous for use in the belt bandage heat shrink. 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 yarns from PA 6.6 are, for example, 940 dtex and 1400 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. However, a higher 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 WO 2017/048207 is known as a strength carrier of the belt bandage a cord of construction PA 6.6 940 x 1 + 1400 x 1. The cord is thus formed from a first yarn of PA 6.6 of fineness 940 dtex and a second yarn of PA 6.6 of fineness 1400 dtex. This provides a cord whose overall fineness of 2340 dtex is between the total fineness of a cord made up of two yarns of fineness 940 dtex and the total fineness of a cord made of two yarns of fineness 1400 dtex. However, this cord has a strong asymmetry in the ratio of the finenesses of the two yarns, which may adversely affect the fatigue resistance of the cord. Furthermore, fine coordination of the properties of the reinforcement layer over the total fineness of the reinforcement used is still not possible with this cord.

The object of the present invention is to provide a cost-effective reinforcement for a reinforcement layer with improved durability and with improved tunability of the strength and the modulus of elasticity of the reinforcement layer, without having to accept disadvantages in rolling resistance.

The object is achieved in that the ratio of the fineness of the second yarn to the fineness of the first yarn is at most 1.34, preferably at most 1.12.

Essential to the invention is that the asymmetry of the cord is low even taking into account the total fineness of the cord. The asymmetry in the ratio of Garnfeinheiten is thereby greatly reduced, whereby possible disadvantages in the fatigue resistance and thus in the durability can be avoided.
Also, with a ratio of the finenesses of the two yarns of at most 1.34, preferably of at most 1.12, a very small gradation of the total fineness of the respective cords is provided by the cords according to the present invention in addition to the symmetrical cords. For example, the following three cords each of two yarns of PA 6.6 have a gradation of only 110 dtex each: 1880x2, 1880x1 + 2100x1, 2100x2.

The selection of total fineness of available cords of yarns with commercial fineness values is thus substantially increased and also possible in a smaller relative gradation than hitherto. Fine adjustments of the strength and the modulus of elasticity of a reinforcement layer can thus be made on the total fineness of the cords. A strong increase in the thread density or a strong increase in the layer thickness is no longer necessary, which disadvantages in the roll holder can be avoided. It is also essential that cost-effective yarns with commercially available fineness values can continue to be used.

Thus, a low-cost strength member for a reinforcement layer having improved durability and improved tunability of the strength and modulus of elasticity of the reinforcement layer is provided without having to suffer from drawbacks in rolling resistance.

In a particularly advantageous embodiment, the fineness of the first yarn is at least 1400 dtex, preferably at least 1880 dtex. By slightly asymmetrical cords of such high fineness, a strongly improved tuning of the properties is made possible even with reinforcement layers with a high strength. In the belt bandage thus good adjustability is also possible for the high-speed range. Concrete cord constructions of yarns of PA 6.6 with standard fineness values are given, for example, by: 1400x1 + 1880x1, 1880x1 + 2100x1.

However, it can also be advantageous if the fineness of the first yarn is at most 700 dtex, preferably at most 350 dtex. Reinforcing layers with cords of such low fineness have a comparatively low layer thickness, which is advantageous for the rolling resistance. For good force / elongation properties very thin calendered layers can be provided with a high number of cords. Concrete cord constructions of yarns of PA 6.6 with commercially available fineness values are given, for example, by: 350x1 + 470x1, 700x1 + 940x1.

Especially with cords having a comparatively large overall fineness, an advantageously low relative grading is made possible if the fineness of the first yarn is at most 480 dtex, preferably at most 240 dtex, particularly preferably at most 220 dtex, smaller 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. At a The difference in fineness of the yarns, as a rule, the change in the properties of a reinforcement layer can be achieved by only a slight change in the thread density without appreciable disadvantages.

As particularly suitable, in particular as a strength carrier for the belt bandage, it has been found that the PA is selected from the group consisting of PA 4.6, PA 6, PA 6.6, PA 10.10, PA 11 and PA 12. These are preferably PA 4.6, PA 6 or PA 6.6. Particularly preferred is PA 6.6.

Commercially available fineness values for yarns of PA 6.6 may be selected from the group consisting of 350 dtex, 470 dtex, 700 dtex, 940 dtex, 1400 dtex, 1880 dtex and 2100 dtex. Yarns from this group generally have good market availability. It is advantageous if the first yarn and / or the second yarn is a yarn of PA 6.6 and has a commercially available fineness value.

It is advantageous if the twist count of all yarns is the same and coincides with the twist count of the cord. Since the differences in fineness of each paired yarn is not very large, the cords may be symmetrically twisted, i. that the twisting numbers of the individual yarns and the cord are the same. As a result, as with a symmetrically twisted cord of two yarns of the same fineness, a cost-effective twist process in the single-stage process is still possible.

In a preferred embodiment, the twist factor α of the cord is 100 to 200, preferably 120 to 180, particularly preferably 130 to 170. 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 allows the use of the reinforcement layer, in particular as a belt bandage in pneumatic vehicle tires, a trouble tire construction including vulcanization and gives the tire a high speed capability.

It is expedient if all the yarns of the cord have the same twisting direction and if the cord has the direction of rotation opposite thereto. Either all the yarns are twisted in the S direction and twisted together in the Z direction to the cord. Or all yarns are twisted in the Z direction and twisted together in the S direction to the cord. Such twisting avoids or reduces internal stresses in the cord.

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. 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 and / or a reinforcement layer of the chipper and / or a reinforcement layer of the flipper. Particularly preferred is a reinforcement layer of the belt bandage. The belt bandage usually has one or two reinforcement layers. It may be carried out according to the invention one or more or all strength layers of the belt bandage.

The invention further relates to a pneumatic vehicle tire having such a reinforcement layer. The pneumatic vehicle tire preferably has a bandage 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.

Table 1 shows examples of cords according to the invention. The cords have exactly the first and the second yarn, which are each made of PA 6.6 and are twisted end to end with the cord. Is indicated also the ratio of the fineness of the second yarn to the fineness of the first yarn, the difference of the finenesses of the two yarns and the total fineness of the cord. Table 1 cord Ratio subtleties Difference subtleties [dtex] Total fineness cord [dtex] 1 350x1 + 470x1 1.34 120 820 2 700x1 + 940x1 1.34 240 1640 3 1400x1 + 1880x1 1.34 480 3280 4 1880x1 + 2100x1 1.12 220 3980

• 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 belt bandage 8th 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 PA. The at least two yarns are twisted together. The ratio of the fineness of the second yarn 22 to the fineness of the first yarn 21 is at most 1.34, preferably at most 1.12.

Also or alternatively, one or more reinforcement layers of the carcass 2 and / or a reinforcement layer of the bead reinforcement in the bead area 4 and / or a chipper and / or a flipper 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 belt bandage 8th , The cord is made of two yarns 21 . 22 made of PA, 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 is at most 1.34, preferably at most 1.12. The PA can be selected from the group consisting of PA 4.6, PA 6, PA 6.6, PA 10.10, PA 11 and PA 12. These are preferably PA 4.6, PA 6 or PA 6.6. For a strength carrier of a belt bandage 8th is particularly suitable for PA 6.6. the fineness of the first yarn 21 may be at most 480 dtex, preferably at most 240 dtex, more preferably at most 220 dtex, smaller than the fineness of the second yarn 22 , The PA can be PA 6.6. The fineness of the first yarn may be at least 1400 dtex, preferably at least 1880 dtex. The fineness of the first yarn can also be at most 700 dtex, preferably at most 350 dtex. Both yarns 21 . 22 and the cord 20 can have the same number of turns. Both yarns 21 . 22 have the same direction of rotation. The cord 20 has the opposite direction of rotation. to better adhesion of the cords 20 to the elastomeric material, the cords 20 be provided with an adhesive impregnation. It can be with the cord 20 to act a cord according to Table 1.

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

• WO 2017/048207 [0008]

Cited non-patent literature

• DIN 60900 [0002]

Claims (10)

Strength support (20) for one of an elastomeric product, preferably for a belt bandage (8) of a pneumatic vehicle tire, wherein the strength support (20) as a cord (20) of at least two yarns (21, 22) of aliphatic polyamide (PA), which end-twisted together are formed, wherein the first yarn (21) has a smaller fineness than the second yarn (22), characterized in that the ratio of the fineness of the second yarn (22) to the fineness of the first yarn (21) is at most 1.34 , preferably at most 1.12. Reinforcement (20) after Claim 1 , characterized in that the fineness of the first yarn (21) is at least 1400 dtex, preferably at least 1880 dtex. Reinforcement (20) after Claim 1 , characterized in that the fineness of the first yarn (21) is at most 700 dtex, preferably at most 350 dtex. 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 480 dtex, preferably at most 240 dtex, particularly preferably at most 220 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 PA is selected from the group consisting of PA 4.6, PA 6, PA 6.6, PA 10.10, PA 11 and PA 12, preferably consisting of PA 6.6. 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 from PA 6.6 and has a commercial Feinheitswert. Reinforcing member (20) according to one or more of the preceding claims, characterized in that the number of twist of all the yarns (21, 22) of the cord (20) is equal and coincides with the twisting number of the cord (20). Reinforcing member (20) according to one or more of the preceding claims, characterized in that the twist factor of the cord (20) is 100 to 200, preferably 120 to 180, particularly preferably 130 to 170. 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 9 ,

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