DE102019200555A1 - Reinforcement layer for objects made of elastomeric material, preferably for pneumatic vehicle tires, and pneumatic vehicle tires - Google Patents

Abstract

The invention relates to a rubberized reinforcement layer for objects made of elastomeric material, preferably for pneumatic vehicle tires, the reinforcement layer having a multiplicity of parallel reinforcement members spaced apart from one another, each reinforcement member being a cord which is twisted from at least two twisted multifilament yarns, at least one of which Multifilament yarns contains polyamide 6 filaments and the multifilament yarns have a yarn titer (fineness) ≤ 1680 dtex. The invention further relates to a pneumatic vehicle tire containing this reinforcement layer. For an optimization of the heat build-up and durability, the cord in the reinforcement layer has a fineness-related maximum tensile force of ≥ 70 cN / tex according to ASTM D885-16.

Description

The invention relates to a rubberized reinforcement layer for objects made of elastomeric material, preferably for pneumatic vehicle tires, the reinforcement layer having a multiplicity of parallel reinforcement members spaced apart from one another, each reinforcement member being a cord which is twisted from at least two twisted multifilament yarns, at least one of which Multifilament yarns contains polyamide 6 filaments and the multifilament yarns have a yarn titer (fineness) ≤ 1680 dtex. The invention further relates to a pneumatic vehicle tire containing this reinforcement layer.

Reinforcement layers for objects made of elastomeric material, such as technical rubber products and pneumatic vehicle tires, are extremely important and are generally known to the person skilled in the art. The reinforcement layers have a large number of reinforcing, thread-like elements, the so-called strength members. These are completely embedded in elastomeric material. The reinforcements of these reinforcement layers have, for example, the form of woven fabrics or calendered, endlessly wound reinforcements.

The rubberized reinforcement layers of a suitable size and design are joined together with other components to form a technical rubber product or a pneumatic vehicle tire. The rubberized reinforcement layers reinforce the product in question.

A wide variety of materials can be used as reinforcement for the reinforcement layers of rubber products. Are known for. B. steel reinforcement or textile reinforcement. As textile reinforcements in the rubber industry, for. B. reinforcements made of polyamide, rayon or polyester are used.

In the context of this application, “multifilament yarn” is to be understood as a multifilament yarn which is twisted and thus has the construction x1 as a reinforcement and which has already undergone the process of hot drawing, including impregnation.
Within the scope of this application, a cord consists of at least 2 multifilament yarns twisted together.

In pneumatic vehicle tires, cords are used as reinforcements, for example in the bead area, as carcass material, for belt plies and in the belt bandage, with rayon and polyamides and different types of polyester being used as the materials for the textile reinforcements.

From the DE 10 2016 214 176 A1 it is known, for example, to use rubberized reinforcement layers for the carcass of pneumatic vehicle cords containing PET. The multifilament yarns made of PET have a yarn titer of 50 to 1100 dtex, a fineness-related maximum tensile strength of ≥ 70 cN / tex and an elongation at break of 10 to 20%.

Polyamide 6 yarns (polycaprolactam yarns) can also be used as reinforcements in rubber products, but these yarns often have a relatively large diameter for sufficient strength. When used in tire components, this has the disadvantage that the calendered layer thickness in the tire is increased. This in turn leads to a greater build-up of heat when the tire is in operation when these layers are exposed to flexing forces. This heat build-up leads to losses in high speed performance and rolling resistance. If yarns with a smaller diameter are used, the number of cords within the reinforcement layers can also be increased for higher strength, but this can lead to problems with durability, since the local load in the rubber between the cords becomes too high.

The invention has for its object to provide a rubberized reinforcement layer which is further optimized with sufficient strength in terms of its heat build-up and durability in the resulting rubber products. It is also the object of the invention to provide a pneumatic vehicle tire which has a aforementioned reinforcement layer and which has an improved rolling resistance.

The object is achieved in that the cord in the reinforcement layer described at the outset has a fineness-related maximum tensile force of ≥ 70 cN / tex in accordance with ASTM D885-16.

Rubberized reinforcement layers can be produced with cords with the maximum tensile force mentioned, which despite a very small diameter of the cords have a high overall strength. This enables a further improvement in the heat build-up in the reinforcement layers produced Rubber products. The amount of rubber material can be further reduced by the even thinner cords. In addition to saving material costs, this results in a thinner rubber layer, which, for example when used as a carcass layer in pneumatic vehicle tires, leads to a reduction in weight and significantly less heat build-up when exposed to walking and centrifugal forces. The latter has a positive effect on rolling resistance and high-speed behavior. In addition, with these reinforcement layers with a lower cord density, the same resilience can be achieved with better durability. The cords are then not as tight and thus reduce the load on the rubber material between the cords.

The reinforcement layer according to the invention meets the requirements for use in particular in vehicle tires, in particular with regard to breaking strength, elastic modulus, fatigue resistance and elongation at break.

The multifilament yarns for the cords of the reinforcement layer are produced in such a way that a raw yarn is spun without any twist, which is then twisted in a twisting machine.

• - der Verdrehung der Multifilamentgarne zur gewünschten Cordkonstruktion
• - des Herstellens einer Cordlage enthaltend den gewünschten Festigkeitsträger
• - der Gummi-Haftungsaktivierung des Cordes, beispielsweise mittels eines RFL-Dips durchführt.

The multifilament yarn is converted to a fabric which can be used for calendering by following the steps known to the person skilled in the art:

• - the twisting of the multifilament yarns to the desired cord construction
• - The production of a cord layer containing the desired reinforcement
• - The rubber adhesion activation of the cord, for example by means of an RFL dip.

It is also possible for the multifilament yarns to be produced as so-called single-end cords, i.e. that is, they are twisted and provided with rubber adhesion activation. Only later do they become a cord layer, e.g. B. processed by winding.

The spinning and converting process are designed so that the cord has a fineness-related maximum tensile strength of ≥ 70 cN / tex according to ASTM D885-16.

Filamante made of different materials can be present within the yarns of a reinforcing cord, at least one of the multifilament yarns containing polyamide 6 filaments. For example, other yarns can consist of filaments of different materials. If there are yarns made of different materials within the reinforcement cord, it is a so-called hybrid cord.

Other materials for the filaments and yarns include, for example, polyesters, aliphatic and aromatic polyamides other than polyamide 6, aramid, polyether ketone, polyketone, polyethylene naphthalate, viscose, natural fibers or glass fibers. The properties of the reinforcement cord can be specifically adjusted by suitable material selection.

According to an advantageous development of the invention, however, the (all) multifilament yarns consist of polyamide 6 filaments. Such yarns can be easily spun and twisted and finally twisted into a cord.

It is useful if the cord has the construction x2 or x3. A cord of 2 or 3 yarns has better fatigue resistance than a twisted multifilament yarn. With constructions higher than x3, the twist costs increase disadvantageously, while other properties, such as the fineness-related strength, can decrease disadvantageously.

It is advantageous if the cord of the reinforcement layers has a construction of 800x2 to 1680x2. In this way, particularly thin reinforcement layers can be realized in conjunction with the high maximum tensile force. In particular, advantages are achieved in relation to the fatigue properties and the rolling resistance of a pneumatic vehicle tire which uses the reinforcement layer according to the invention, and in relation to the process capability of the reinforcement layer production.

In order to obtain sufficient fatigue resistance of the reinforcing cords, it is advantageous if the twist factor α of each multifilament yarn or cord is in a range from 150 to 250, preferably in a range from 175 and 225, the twist factor α being as follows Formula calculated: α = twist [t / m]. (Fineness [tex] / 1000) ^1/2 . The twist factor is a measure of the final twist per meter of the cord, based on the fineness of the cord. Set the specified ranges for the twist factor an advantageous compromise in terms of fatigue resistance and strength. A lower twist factor would be disadvantageous in terms of fatigue resistance, a higher twist factor would mean a lower strength of the reinforcement.

According to a preferred development of the invention, the cords are arranged in the reinforcement layer in a density of 60 to 120 epdm (ends per decimeter), preferably in a density of 60 to 100 epdm. Due to the increased fineness-related maximum tensile strength of the cord with polyamide 6 filaments compared to the prior art, the cord can be arranged in a lower density in the reinforcement layer, as a result of which a higher durability is achieved, the production of this layer is easier and also a cost advantage due to the reduced Use of reinforcement is achieved. There is also less risk of the semi-finished product being damaged when it is cut into the required strip width.

For a further improvement in fatigue resistance and a reduction in costs, it has proven to be advantageous if the maximum tensile force of the layer HL = maximum tensile force (according to ASTM D885-16) / epdm is between 15 and 25 kN.

In order to ensure reliable adhesion of textile reinforcements to the rubber, it is expedient to coat the reinforcing cord according to the invention with an adhesive impregnation, e.g. to be provided with an RFL dip in a 1 or 2 bath process.

The reinforcement layer according to the invention can be used in a wide variety of elastomeric products, such as belts, conveyor belts, hoses or air springs.

It is advantageous if the reinforcement layer is a belt layer of a diagonal belt tire. Due to its physical properties, the reinforcement layer is particularly suitable for use as a belt layer. You get tires with good durability and low rolling resistance.

Alternatively, the reinforcement layer can also be used as the carcass layer of a pneumatic vehicle tire. Here, too, there are advantages in terms of durability and rolling resistance in the tire due to a reduced layer thickness.

The invention is achieved in relation to the pneumatic vehicle tire in that it has a rubberized reinforcement layer as described above. The pneumatic vehicle tire has improved rolling resistance. With a higher reinforcement density in the reinforcement layer, the pneumatic vehicle tire has an improved high-speed performance.

The invention is explained in more detail below on the basis of exemplary embodiments, but without being restricted to these.

Table 1 shows different rubberized reinforcement layers with their properties, all reinforcement layers having cords made of polyamide 6 filaments. property unit State of the art location Layer 1 according to the invention Layer 1 according to the invention Delicacy and construction dtex 1870x2 1400x2 1400x2 twist tpm 320 370 370 Twist factor α - 195 195 195 Shrink 5 min / 160 ° C % 6 6 6 Maximum traction N 280 224 280 Fineness-related maximum tensile force (ASTM D 885-16) cN / tex 80 80 100 Thread density epdm 80 100 80 Maximum tensile force of the layer (ASTM D 885-16) kN 22.4 22.4 22.4

In the cords in the layers according to the invention, the twist was raised in order to obtain the same twist factor. Starting from a layer with a cord from the prior art with a fineness of 1870 dtex, layers with the same maximum tensile strength could be obtained, but with cords of a fineness of only 1400 dtex. In this way it is possible to obtain thinner reinforcement layers with the same strength.

In rubber products, in particular vehicle tires, with such a reinforcement layer, this leads to a reduction in weight and significantly less heat build-up when subjected to flexing and centrifugal forces. The durability is improved and tires have positive effects in terms of rolling resistance and high-speed behavior.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• DE 102016214176 A1 [0007]

Claims (11)

Rubberized reinforcement layer for objects made of elastomeric material, preferably for pneumatic vehicle tires, the reinforcement layer having a multiplicity of parallel reinforcement members arranged at a distance from one another, each reinforcement member being a cord which is twisted from at least two twisted multifilament yarns, at least one of the multifilament yarns polyamide 6- Contains filaments and the multifilament yarns have a yarn titer (fineness) ≤ 1680 dtex, characterized in that the cord has a fineness-related maximum tensile strength of ≥ 70 cN / tex according to ASTM D885-16. Reinforcement layer after Claim 1 , characterized in that the multifilament yarns consist of polyamide 6 filaments. Reinforcement layer according to one or more of the preceding claims, characterized in that the cord has the construction x2 or x3 Reinforcement layer according to one or more of the preceding claims, characterized in that the cord has a construction of 800x2 to 1680x2. Reinforcement layer according to one or more of the preceding claims, characterized in that the twist factor α of each multifilament yarn or cord is in a range from 150 to 250, preferably in a range from 175 to 225, where α = twist [t / m]. (Fineness [tex] / 1000) ^1/2 . Reinforcement layer according to one or more of the preceding claims, characterized in that the reinforcement is a cord made of two twisted multifilament yarns made of polyamide 6 filaments and that the cords are arranged in a density of 60-120 epdm in the reinforcement layer. Reinforcement layer after Claim 6 , characterized in that the cords are arranged in a density of 60-100 epdm in the reinforcement layer. Reinforcement layer according to at least one of the preceding claims, characterized in that the maximum tensile force of the layer HL = maximum tensile force (according to ASTM D885-16) / epdm is between 15 and 25 kN. Reinforcement layer according to at least one of the preceding claims, characterized in that it is a belt layer of a diagonal belt tire. Reinforcement layer according to one of the preceding Claims 1 to 8th , characterized in that it is a carcass ply of a pneumatic vehicle tire. Pneumatic vehicle tire, which has a reinforcement layer according to one of the preceding claims.