Vehicle tyre having a polymer-based tyre sealant and use of the tyre sealant in vehicle tyres

Abstract

The invention relates to a vehicle tyre having a polymer-based tyre sealant, which is applied to the inner side of the vehicle tyre, wherein the average layer thickness of the applied tyre sealant is greater than 4 mm. The invention also relates to the use of such a polymer-based tyre sealant in vehicle tyres.

Description

[0001] Description

[0002] Vehicle tires comprising a polymer-based tire sealant and use of the tire sealant in vehicle tires

[0003] The invention relates to a vehicle tire having a polymer-based tire sealant according to the preamble of patent claim 1 and to the use of such a tire sealant in the vehicle tire according to patent claim 7.

[0004] Polymer-based tire sealants are known in the prior art. DE102007023094B4 discloses a method for producing a tire with a polymer-based sealant, wherein a highly viscous first sealant component, comprising a rubber component that is blend-free or blended with at least one other rubber component, and blending ingredients that are free of a solvent and an activator, is mixed with at least one second sealant component, comprising a low-viscosity and separately produced medium containing at least one activator, to form the tire sealant. Crosslinking occurs, followed by the subsequent introduction of the tire sealant into the inner surface of the tire.

[0005] The use of such a tire sealant for tires with a high load index, particularly for C tires (commercial tires), such as van tires and light truck tires, is unknown in the prior art. Vans are known in the prior art and are broadly referred to as vehicles with a raised body, high-roof station wagons, and minibuses. Light trucks are also known in the prior art. Likewise unknown is the use of such a tire sealant in D tires, E tires, and F tires. C, D, E, and F tire types have a higher load capacity than P tires (passenger tires) and therefore have a reinforced structure.

[0006] The object of the invention is to provide a vehicle tire, preferably a C-tire, D-tire, E-tire, or F-tire, in particular with a load index of at least 86, preferably for vans or light trucks, which has improved sealing properties. Furthermore, the object of the invention is to improve the driving safety of motor vehicles having vehicle tires, preferably C-tire, D-tire, E-tire, or F-tire, preferably with a load index of at least 86.

[0007] The object of the invention is achieved by a vehicle tire having the features of patent claim 1. Furthermore, the object of the invention is achieved by the use of such a tire having the features of patent claim 7.

[0008] The object of the invention is achieved by a vehicle tire comprising a polymer-based tire sealant which is applied to the inside of the vehicle tire, wherein the average layer thickness of the applied tire sealant is greater than 4 mm.

[0009] Surprisingly, it was found that the use of a polymer-based tire sealant in vehicle tires according to the invention, especially with a load index of at least 86, leads to improved sealing. Furthermore, it is advantageous that such vehicle tires can be used in vans and / or light trucks and lead to improved driving safety.

[0010] The average layer thickness according to the invention is determined on average over the entire inner surface of the vehicle tire to which the tire sealant is applied. The layer thickness can be determined, for example, by image analysis of an X-ray image of the vehicle tire.

[0011] In one embodiment of the invention, the vehicle tire comprises a polymer-based tire sealant, in particular produced according to a process described in DE102007023094B, wherein the tire sealant is produced according to a process for producing a tire sealant, wherein a highly viscous first sealant component, comprising a rubber component that is free of blends or blended with at least one further rubber component, as well as mixing ingredients that are free of a solvent and an activator, is mixed with at least one second sealant component, comprising a low-viscosity and separately produced medium that contains at least one activator, to form the tire sealant, wherein crosslinking takes place, combined with the subsequent introduction of the tire sealant into the inside of the tire, characterized by at least the following process steps:

[0012] - the first sealant component is prepared using a twin-screw extruder;

[0013] - the second sealant component is produced separately on a stirrer;

[0014] - the first sealant component and the second sealant component are fed separately to a dosing device by pumping, wherein the pumping and dosing of the first sealant component is carried out by a diaphragm dosing device and the pumping and dosing of the second sealant component is carried out by means of a diaphragm dosing device

[0015] - now the high-viscosity first sealant component is mixed with the low-viscosity second sealant component in a mixing device to form the tire sealant;

[0016] - the tire is now preheated before its contact with the tire sealant, which accelerates the cross-linking and thus the curing of the tire sealant

[0017] - the tyre sealant is then introduced into the inside of a rotating tyre, whereby the tyre sealant is introduced in such a way that an endless bead is placed in the tyre, which covers the inside of the tyre to be covered by means of a coil pattern;

[0018] - finally, the tire sealant is allowed to solidify, thereby achieving the sealing effect.

[0019] Advantageously, the use of this tire sealant in vehicle tires with a load index of at least 86 leads to improved driving safety in vans and light trucks.

[0020] In a further embodiment of the invention, the layer thickness of the

[0021] Tire sealant in the range from 4 mm to 8 mm, preferably in the range from 4.5 mm to 8 mm, particularly preferably in the range from 5 mm to 8 mm. A significant surprising aspect is that this layer thickness leads to improved impermeability of vehicle tires, in particular with a load index of at least 86. Furthermore, the vehicle tire preferably has a layer thickness of at least 4.5 mm or at least 5 mm. A layer thickness of at least 4.5 mm or at least 5 mm is advantageous for C tires, D tires, E tires, or F tires. It has been found to be advantageous that a greater layer thickness leads to improved impermeability of these tires.

[0022] In a further embodiment of the invention, the tire sealant has a tan d at 100°C in the range of 0.2 to 0.9, in particular in the range of 0.4 to 0.6. It has been found that the tire sealant with the density according to the invention is advantageous for vehicle tires with a load index of at least 86 and leads to improved vehicle safety.

[0023] The tan d is measured using a rheometer, e.g., a HAAKE RheoStress 6000 from Thermo Scientific, or validated by cross-checking by MSE CME. The measurement was performed using the following parameters: normal force F 1,700 N, temperature 100 °C, shear stress 200 Pa, and frequency 10.00–0.01 Hz.

[0024] In a further embodiment of the invention, the creep behavior of the tire sealant is in the range of 0.2 mm to 6.0 mm, in particular in the range of 2.0 mm to 4.0 mm. Advantageously, the tire sealant exhibiting such creep behavior leads to significantly improved sealing in vehicle tires, in particular in vehicle tires with a load index of at least 86.

[0025] The vertical creep behavior of the tire sealant after vulcanization is determined using the following equipment: plug drill, diameter 10 mm, graph paper, approximately 100 mm x 150 mm, precision balance, accuracy ±0.0 lg, camera, beaker, 400 ml low mold, stopwatch, drying oven at 125°C. The test is carried out using the following procedural steps: A 10 mm diameter sample is punched out using a plug drill; the scale is tared with the graph paper. The sample is placed in the upper third of the graph paper and then weighed. The weight of the sample must be within the specified tolerance range ±0.05; the sample on the graph paper is photographed. To investigate the flow behavior, the graph paper is placed with the sample facing up in a 400 ml beaker and heated in a drying oven at 125°C for 30 minutes. After heating, the sample is photographed again.

[0026] In a further embodiment of the invention, the vehicle tire has a load index of at least 86, preferably at least 90, more preferably at least 95, and most preferably at least 100. Tires with a designation selected from a group comprising C, D, E, and F designations, also referred to as C, D, E, or F tires, have such a load index. Vehicle tires with a C designation are used primarily in commercial vehicles. They are standardized according to ECE R 54 and differ from passenger car tires. The letter C, for example, stands for Commercial and indicates the reinforced carcass structure; both the carcass and the belt are particularly robust in design. Such belt constructions preferably have a 2+2x0.32 HT, although other belt constructions are also conceivable.The use of the above-mentioned tire sealant in these vehicle tires leads to improved performance of the tire sealant in terms of sealing. This tire is manufactured with a multi-layer tire base and is used in trucks, vans, off-road vehicles, commercial vehicles, and sometimes in SUVs. In a particular embodiment of the invention, the vehicle tire has a load index in the range of 86 to 131, preferably in the range of 90 to 131, particularly preferably in the range of 95 to 131. It is advantageous that the vehicle tire comprising such a tire sealant is advantageous for tires with a higher load index, as this exhibits improved sealing. C tires have a ply rate of 6 PR, D tires 8 PR, E tires 10 PR, and F tires 12 PR. The ply rate is an indicator of a tire's load capacity.The invention further relates to the use of a polymer-based tire sealant for a described vehicle tire, wherein the vehicle tire has an internal pressure in the range between 375 kPa and 575 kPa, wherein the vehicle tire preferably has a load index of at least 86. It has been found to be advantageous that the use of such a tire sealant in such vehicle tires leads to improved vehicle safety. The internal pressure of the vehicle tire can preferably be related to the ply rate. Thus, tires with 6 PR have an internal pressure in the range of 375 kPa. Tires with 8 PR have an internal pressure in the range of 475 kPa, and tires with 10 PR have an internal pressure in the range of 575 kPa. Preferably, the vehicle tire comprising a polymer-based tire sealant is a tire with a marking in the range between 6 PR and 10 PR.

[0027] Further advantages and features of the vehicle tire according to the invention, as well as the use of the vehicle tire, emerge from the subclaims, which relate to advantageous embodiments of the present invention and are not to be understood as limiting. The invention also encompasses combinations of the features of various subclaims, insofar as these are technically possible, even if the subclaims do not relate to one another or if they belong to different claim categories. Furthermore, combinations of preferred and particularly preferred embodiments can also be combined with one another, insofar as these are technically possible.

Claims

Patent claims 1. Vehicle tire comprising a polymer-based tire sealant applied to the inside of the vehicle tire, characterized in that the average layer thickness of the applied tire sealant is greater than 4 mm.

2. Vehicle tire according to claim 1, characterized in that the layer thickness of the tire sealant is in the range from 4 mm to 8 mm, preferably in the range from 4.5 mm to 8 mm, particularly preferably in the range from 5 mm to 8 mm.

3. Vehicle tire according to claim 1 or 2, characterized in that the tire sealant has a tan d at 100°C in the range from 0.2 to 0.9, in particular in the range from 0.4 to 0.

6.

4. Vehicle tire according to one of the preceding claims, characterized in that the creep behavior of the tire sealant is in the range from 0.2 mm to 6.0 mm, in particular in the range from 2.0 mm to 4.0 mm.

5. Vehicle tire according to one of the preceding claims, characterized in that the vehicle tire has a load index of at least 86, preferably at least 90, particularly preferably at least 95, most particularly preferably at least 100.

6. Vehicle tire according to one of the preceding claims, characterized in that the vehicle tire is at least one tire selected from the group consisting of C tires, D tires, E tires and F tires.

7. Use of a polymer-based tire sealant for vehicle tires according to one of the preceding claims, wherein the vehicle tire has an internal pressure in Range between 375 kPa and 575 kPa, wherein the vehicle tire preferably has a load index of at least 86.