Resin-free sealing agent for provisionally sealing pneumatic vehicle tyres, sealing agent container comprising same, method for provisionally sealing pneumatic vehicle tyre, and use

Abstract

To provide a resin-free sealing agent for provisionally sealing pneumatic vehicle tyres.SOLUTION: The sealing agent contains at least one rubber latex, at least one stabilizer, and water. In addition, the invention relates to a sealing agent container containing a resin-free sealing agent and to a method for provisionally sealing a pneumatic vehicle tyre.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin-free sealant for the temporary sealing of pneumatic vehicle tyres according to the preamble of claim 1, and to a sealant container comprising such a resin-free sealant according to the preamble of claim 8. The present invention also relates to a method for the temporary sealing of pneumatic vehicle tyres according to the preamble of claim 9, and to the use of such a sealant according to the preamble of claim 10. [Background technology]

[0002] When a pneumatic vehicle tire runs over a sharp object, it can be damaged in the form of cracks that lead to a loss of tire air pressure. To seal such damage with maximum reliability, at least temporarily, i.e., for a certain period before the vehicle tire is replaced, there are known prior art sealants that are introduced into the tire by a tire repair kit, for example, after the valve insert is unscrewed and extracted, or directly through the valve. Such tire repair kits typically include a pressure source and a sealant container or at least one connector for a sealant container. Alternatively, the sealant is pumped directly into the tire from the container by the user.

[0003] For example, European Patent No. 3227097B1 discloses a sealing means comprising rubber latex, a tackifying resin, and an antifreeze agent. The drawback of the sealants described in the prior art is that the compositions do not have the desired properties in terms of sealing performance for tires. Summary of the Invention [Problem to be solved by the invention]

[0004] This is the starting point of the present invention. An object of the present invention is to provide an improved sealant having improved performance, particularly with respect to pumpability and sealing performance. A further object of the present invention is to provide an improved sealant container containing a sealant that provides better sealing of pneumatic vehicle tires. [Means for solving the problem]

[0005] The object of the present invention is achieved by a resin-free sealant for temporary sealing of pneumatic vehicle tires having the features of claim 1. The object is further achieved by a sealant container having the features of claim 8 and a method for temporary sealing of pneumatic vehicle tires having the features of claim 9.

[0006] The object is achieved by a resin-free sealant for the temporary sealing of pneumatic vehicle tires, which comprises at least one rubber latex, at least one stabilizer, and water.

[0007] The resin-free sealant of the present invention surprisingly has a significantly improved sealing performance. This ultimately leads to improved functionality of the sealant of the present invention compared to current sealants. Further advantageous performance characteristics are exhibited by the resin-free sealant of the present invention in terms of pumpability and aerosol efficiency. The resin-free sealant can also be produced inexpensively.

[0008] Unless otherwise stated, all weight data are based on the total amount of sealant or composition for temporary sealing of pneumatic vehicle tires. DETAILED DESCRIPTION OF THE INVENTION

[0009] In one embodiment of the present invention, the rubber latex comprises or consists of NR latex. The rubber latex can be natural rubber latex (NR) from the Hevea brasiliensis tree, or alternatively from guayule (Parthenium argentatum), which can be used in deprotonated form. A possible alternative is for the latex to be produced synthetically and used. For this purpose, the use of various blended latexes and mixtures of NR and synthetic latex are also conceivable.

[0010] In a preferred embodiment of the present invention, the sealant has a latex content in the range of 27% to 46% by weight, preferably in the range of 36% to 45% by weight. The great advantage of a sealant having such a latex content is that the pumpability and aerosol efficiency are significantly improved, and therefore the sealant has higher performance.

[0011] In one embodiment of the present invention, the sealant contains at least one antifreeze agent, preferably at least two antifreeze agents, and in particular, at least one antifreeze agent contains at least one glycol selected from the group consisting of ethanediol and propanediol. Antifreeze agents in this context typically have a low freezing point, typically below -10°C. When combined with water, the freezing point can be even lower, reaching -55°C in the appropriate mixture. Advantageously, a sealant with a low freezing point can be used in colder climates without significantly impairing pumpability and flowability. More preferably, the first antifreeze agent contains 1,2-ethanediol, and the second antifreeze agent contains 1,2-propanediol. Both antifreeze agents are miscible with water and lower the freezing point. It is also advantageous that sealants containing such antifreeze agents are more environmentally friendly.

[0012] In a further embodiment of the present invention, the total proportion of the antifreeze agents is preferably in the range of 27% to 40% by weight, in particular, the proportion of the first antifreeze agent is in the range of 20% to 25% by weight and the proportion of the second antifreeze agent is in the range of 7% to 15% by weight. Advantageously, this total proportion of the antifreeze agents is optimal for depressing the freezing point of the entire sealant, resulting in a sealant with optimal pumpability and flowability and improved sealing properties even at relatively low temperatures.

[0013] In a further embodiment of the present invention, the at least one stabilizer is a surfactant, and preferably the total proportion of surfactants is in the range of 0.25% to 5% by weight. Advantageously, the at least one surfactant stabilizes at least the latex, especially the antifreeze, resulting in an overall stabilization of the resin-free sealant.

[0014] More preferably, the sealant comprises two surfactants, and the total proportion of the first surfactant and the second surfactant is in the range of 0.5% by weight to 2% by weight. Advantageously, the two surfactants can interact with each other and other components, thereby improving the transport and sealing performance.

[0015] More preferably, the at least one surfactant comprises one or more sulfonates, particularly anionic mono- or disulfonates, and / or at least one alkyl ether sulfate, such as sodium alkylphenol polyethylene glycol ether sulfate, and at least one steric surfactant. These advantageously are excellent foam-forming agents, significantly improving sealing in pneumatic vehicle tires. The steric surfactant exhibits excellent viscosity and foam control properties for the sealant.

[0016] In a further embodiment of the present invention, the resin-free sealant contains further additives. For example, an aging stabilizer or preservative can be added to the resin-free sealant to ensure that the sealant is ready to use during storage. Additionally, the sealant may contain a dispersant and / or an emulsifier and / or a pH adjuster. A major advantage is that the resin-free sealant exhibits much better sealing performance.

[0017] In a preferred embodiment, the sealant comprises 1% to 2% by weight of at least one ageing stabilizer, in particular a dispersion of a sterically hindered and alkylated (poly)phenol and / or alkylated diphenylamine, thus advantageously extending the life of the sealant.

[0018] In a further embodiment, the resin-free sealant contains fillers that contribute to sealing particularly large pores. Examples include fibrous materials, especially natural and synthetic fibers, layered silicates, silica, talc, chalk, carbon black, ground rubber, and the like.

[0019] In a further embodiment of the invention, the resin-free sealant has a viscosity of 3 to 23 mPa·s, in particular 6 to 16 mPa·s, at 25° C. (dynamic viscosity in a rheometer, 0.5° cone, 16000 rpm), which significantly improves the flow properties of the sealant.

[0020] In a further embodiment of the present invention, the water content of the resin-free sealant is in the range of 15% to 30% by weight, particularly in the range of 20% to 25% by weight. This is achieved using a latex that is an aqueous dispersion (emulsion) of up to 85% by weight, preferably up to 70% by weight. This means that the proportion of solids in the dispersion based on the total weight is up to 85% by weight, preferably up to 70% by weight. Alternatively, the proportion of solids in the dispersion based on the total weight can be in the range of 85% to 70% by weight, particularly in the range of 80% to 75% by weight. Advantageously, a resin-free sealant with such a water content and / or solids content has much higher sealing performance without the use of resin.

[0021] Additionally, the objects of the present invention are achieved by a sealant container containing the resin-free sealant as described, the sealant container having an opening through which the resin-free sealant can be delivered into a vehicle tire.

[0022] Advantageously, the sealant container of the present invention is easy to use, since the resin-free sealant can be easily poured out of the sealant container. It is conceivable that a user can press or squeeze the container by hand to deliver the sealant into a vehicle tire. For this purpose, the sealant can be connected to a vehicle tire valve, for example, via a hose. Alternatively, such a container can be connected to a tire repair kit via a hose. Similarly, it is conceivable that the resin-free sealant can be squeezed into a tire repair kit, in which case the tire repair kit is designed to generate compressed air using a compressor, and the compressed air delivers the resin-free sealant into the vehicle tire.

[0023] Details and advantages relating to resin-free encapsulants are equally applicable to resin-free encapsulants contained in encapsulant containers, and vice versa.

[0024] In one embodiment of the present invention, the sealant container can be connected to a tire repair kit. For this purpose, the sealant container has a connector that can be connected to the tire repair kit, for example, via a plug mechanism or a rotating mechanism. Advantageously, such a sealant container can be connected to a tire repair kit, which greatly simplifies user operation. It has also been found that a sealant container containing a resin-free sealant leads to significantly improved sealing performance.

[0025] The objects of the present invention are also achieved by a method for temporarily sealing a pneumatic vehicle tire using at least one resin-free sealant, which has significantly improved sealing performance, making it easier for users to seal pneumatic vehicle tires.

[0026] Details and advantages relating to resin-free encapsulants and encapsulant containers are equally applicable to the method of the present invention, and vice versa.

[0027] In one embodiment of the method of the present invention, the sealant is sprayed into the vehicle tire through the valve, which can be achieved, inter alia, by a tire repair kit including a compressor that generates compressed air that conveys the sealant through a hose into the vehicle tire.

[0028] The present invention further relates to the use of the resin-free sealant as described in a tire repair kit for a pneumatic vehicle tire.

[0029] Further advantages and features of the resin-free sealant, sealant container, and method of the present invention will become apparent not only from the description but also from the dependent claims, which relate to advantageous configurations of the present invention and therefore should not be considered limiting. The present invention also encompasses combinations of features of different dependent claims, even if the dependent claims are not related to each other or belong to different claim categories. Furthermore, combinations of preferred and particularly preferred embodiments can be combined with each other. This also applies to individual features of the working examples described below that a person skilled in the art would not necessarily recognize as belonging together.

[0030] The present invention is illustrated in detail by the following working examples. Examples identified with a "C" are comparative examples. Compositions of the present invention are identified with an "I".

[0031] It can be inferred from Table 1 that the examples of the present invention show much better sealing performance, which translates to improved encapsulant performance for the user compared to encapsulants containing resin. The substances used were as follows: a) 60% solids by weight, LATZ natural latex, e.g., Weber & Schaer b) Rosin ester, 50% solids by weight, Tacolyn, Eastman Chemical Company c) Aromatic modified terpene resin, Nanolet TO, Yasuhara Chemical Co. Ltd. d) Anionic disulfonate, 51% active solids by weight e) Sodium trialkylphenol polyethylene glycol ether sulfate, 25% active solids by weight f) Resin / latex ratio, which refers to the solids content of the latex and resin

[0032] [Table 1]

[0033] definition In the context of the present invention, sealing performance is confirmed by introducing a sealant into a defective pneumatic vehicle tire and simulating a first driving cycle for 10 minutes. The tire's integrity is then tested using a leak detection spray and classified as airtight or leaking. For the exemplary number 4 / 10, 10 pneumatic vehicle tires are tested, and after 10 minutes, four are airtight and six are leaking. After the first driving cycle, a second driving cycle is performed for 10 minutes, and then the integrity is tested again.

[0034] In the context of the present invention, pumpability is confirmed by testing system performance in a test setup consisting of a wheel, tire valve, and compressor sealant system as follows.

[0035] The wheel is filled with sealant and compressed air using a compressor until a target filling pressure of 220 kPa is reached. During this operation, the prevailing pressure in the compressor and in the wheel is measured simultaneously. When the target filling pressure of 220 kPa is reached, the filling operation is stopped and the time required to reach this 220 kPa is recorded. The shorter the required time, the more stable the sealant mixture is with respect to drying and shear-induced solidification. A short run time of the system is most advantageous to the end user.

[0036] Additionally, aerosol efficiency is confirmed in the context of the present invention by using the following test setup.

[0037] A wheel consisting of a tire and a wheel rim is pierced at a predetermined point in the tire tread with a nail having a diameter of 6 mm. This creates a hole that can be characterized by the pressure drop per unit time when the tire is filled with air. Specifically, the pressure drop from 250 kPa that occurs after one minute is measured. The greater the pressure drop, the larger the hole in the tire.

[0038] To determine the aerosol sealing efficiency, the pressure drop from 250 kPa within one minute was measured exactly twice: once before the sealant was transferred into the wheel using a compressor and once after the sealant was transferred into the wheel using a compressor. During the transfer of the sealant, a mixture of sealant and air (aerosol) was formed within the wheel, and this mixture was carried through the pores in the tire tread by the positive pressure within the tire. This mixture has the ability to solidify when subjected to shear. For these reasons (positive pressure, solidification ability), the pores are significantly reduced in size by the sealant, and the pore size correlates with a smaller pressure drop from 250 kPa over one minute. Next, to determine the aerosol sealing efficiency, the difference in pressure drop between the "wheel without sealant" and the "wheel with sealant" was calculated. The larger the difference, the more effective the sealant is in terms of its aerosol efficiency. This is also most advantageous for the user, as it shortens the total pumping time of the system.

[0039] Embodiment 1. A resin-free sealant for temporary sealing of pneumatic vehicle tires, comprising: A resin-free sealant, characterized in that the sealant comprises at least one rubber latex, at least one stabilizer, and water. 2. The resin-free sealant according to claim 1, characterized in that the rubber latex comprises or consists of NR latex. 3. A resin-free sealant according to claim 1 or 2, characterized in that the sealant has a latex content in the range of 27% to 46% by weight, preferably in the range of 36% to 45% by weight. 4. A resin-free sealant according to any one of claims 1 to 3, characterized in that the sealant contains at least one antifreeze agent, preferably at least two antifreeze agents, and in particular, the at least one antifreeze agent contains at least one glycol selected from the group consisting of ethanediol and propanediol. 5. The resin-free sealant according to claim 4, characterized in that the total proportion of the antifreeze agents is in the range of 27% to 40% by weight, and in particular, the proportion of the first antifreeze agent is in the range of 20% to 25% by weight, and the proportion of the second antifreeze agent is in the range of 7% to 15% by weight. 6. A resin-free sealant described in any one of claims 1 to 5, characterized in that at least one stabilizer is a surfactant, and preferably the total proportion of surfactants is within the range of 0.25% by weight to 5% by weight. 7. The resin-free sealant according to any one of claims 1 to 6, characterized in that the water content is in the range of 15% by weight to 30% by weight, particularly in the range of 20% by weight to 25% by weight. 8. A sealant container containing the resin-free sealant according to any one of claims 1 to 7, characterized in that the sealant container has an opening through which the resin-free sealant can be transported into a vehicle tire. 9. The sealant container according to claim 8, characterized in that the sealant container is connectable to a tire repair kit. 10. A method for temporarily sealing a pneumatic vehicle tire using at least one resin-free sealant according to any one of claims 1 to 7. 11. The method of claim 10, wherein the sealant is sprayed into the interior of a pneumatic vehicle tire through the valve. 12. Use of the resin-free sealant according to any one of claims 1 to 7 in a tire repair kit for pneumatic vehicle tires.

Claims

1. A resin-free sealant for temporary sealing of a vehicle pneumatic tire, comprising: The resin-free sealant comprises at least one rubber latex, at least one stabilizer, and water.

2. 2. The resin-free sealant of claim 1, wherein the rubber latex comprises or consists of NR latex.

3. 3. The resin-free sealant according to claim 1 or 2, characterized in that the sealant has a latex content in the range of 27% to 46% by weight, preferably in the range of 36% to 45% by weight.

4. 4. The resin-free sealant according to claim 1, wherein the sealant comprises at least one antifreeze agent, preferably at least two antifreeze agents, in particular at least one antifreeze agent comprising at least one glycol selected from the group consisting of ethanediol and propanediol.

5. The resin-free sealant according to claim 4, characterized in that the total proportion of the antifreeze agents is in the range of 27% to 40% by weight, and in particular, the proportion of the first antifreeze agent is in the range of 20% to 25% by weight, and the proportion of the second antifreeze agent is in the range of 7% to 15% by weight.

6. The resin-free sealant according to any one of claims 1 to 5, characterized in that the at least one stabilizer is a surfactant, and preferably the total proportion of the surfactant is in the range of 0.25 wt% to 5 wt%.

7. The resin-free sealant according to any one of claims 1 to 6, characterized in that the water content is in the range of 15% to 30% by weight, in particular in the range of 20% to 25% by weight.

8. A sealant container containing the resin-free sealant according to any one of claims 1 to 7, characterized in that the sealant container has an opening through which the resin-free sealant can be transported into a vehicle tire.

9. A method for temporarily sealing a pneumatic vehicle tire using at least one resin-free sealant according to any one of claims 1 to 7.

10. Use of the resin-free sealant according to any one of claims 1 to 7 in a tire repair kit for pneumatic vehicle tires.

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