SEALANT FOR A VEHICLE PNEUMATIC TIRE, SEALANT CONTAINER WITH SUCH A CONTAINER AND METHOD FOR PROVISIONALLY SEALING VEHICLE PNEUMATIC TIRE

Description

[0001] The invention relates to a sealant for the temporary sealing of vehicle pneumatic tires according to the preamble of claim 1 and to a sealant container with such a sealant according to the preamble of claim 7. Furthermore, the invention relates to a method for the temporary sealing of a vehicle pneumatic tire using at least one such sealant according to the preamble of claim 8.

[0002] Vehicle tires can be damaged by sharp objects, resulting in punctures and subsequent loss of air pressure. To seal such damage, at least temporarily until the tire can be replaced, sealants are known in the art. These sealants are applied to the tire, for example, using a tire repair kit, either after removing the valve core or directly through the valve. Such a kit typically includes a pressure source and a sealant reservoir, or at least a connection for one. Alternatively, the user can squeeze the sealant directly from the reservoir into the tire.

[0003] DE 112010000061 T9, for example, discloses a sealant for tire punctures which comprises a surfactant content of between 1.0 and 6.0 percent by mass of the solids content of the natural rubber latex. Such a sealant exhibits increased shelf life, although the surfactant is also a factor that causes a loss of sealing performance.

[0004] Further sealants according to the prior art are disclosed in the documents US 2015 / 337155 A1, which describes a sealant with a high rubber latex content, DE 11 2016 001538 T5 and US 2017 / 066206 A1, which describe sealants with high resin content.

[0005] A key characteristic of a sealant for sealing vehicle tires is the diametrically opposed relationship between valve clogging and sealing performance, which changes with the aging of the sealant. A freshly manufactured sealant tends to clog valves but seals reliably. Aged sealant shows little valve clogging but seals less reliably.

[0006] This is where the present invention comes in. The present invention is based on the objective of providing a sealant that exhibits improved properties with regard to its usability, particularly with respect to the described diametrical behavior. Furthermore, the object of the present invention is to provide a sealant container with a sealant that improves the usability of the sealant container. Finally, the invention is based on the objective of providing a method for the temporary sealing of a vehicle tire, which improves its usability, particularly with respect to its diametrical behavior.

[0007] The object of the invention is achieved by a sealant for the temporary sealing of vehicle pneumatic tires with the features of claim 1. Furthermore, the object is achieved by a sealant container with the features of claim 7 and by the use of the sealant according to claim 8.

[0008] The object of the invention is solved by a sealant for the temporary sealing of vehicle pneumatic tires, comprising at least a rubber latex, at least a resin and at least a surfactant, wherein the solid content of the surfactant is in the range of 6.5 wt.% to 12 wt.% in relation to the solid content of the rubber latex.

[0009] Advantageously, the sealant according to the invention exhibits significantly improved diametrically opposed behavior with respect to valve clogging and sealing performance. It has been found that the solids content of the surfactant according to the invention, in relation to the latex and the resin, is optimal with regard to valve clogging and sealing performance, so that the sealant exhibits reliable sealing properties for a long time and is also more reliable with respect to valve clogging. Overall, the usability of the sealant according to the invention is more user-friendly and thus significantly better than that of sealants in the prior art. Furthermore, the use of a sealant according to the invention is more cost-effective for the user, since, due to the improved sealing performance compared to the prior art, less sealant is required.

[0010] Unless otherwise stated, all weight specifications refer to the total quantity of sealant or the total quantity of means for temporarily sealing vehicle pneumatic tires.

[0011] In one embodiment of the invention, the solids content of the surfactant is in the range of 7 wt.% to 11 wt.%, preferably in the range of 8 wt.% to 10 wt.%. It is advantageous that the sealant exhibits even better diametrical behavior with such a selected or preferred range.

[0012] In a further embodiment of the invention, the at least one surfactant comprises a block copolymer of propylene oxide and ethylene oxide, wherein the proportion of ethylene oxide is preferably 40 wt.%. It has been advantageously found that such a block copolymer leads to a significantly improved diametrically opposed behavior of the sealant with respect to the properties of valve clogging and sealing performance.

[0013] In a preferred and / or further embodiment, the at least one surfactant comprises one or more sulfonates, in particular 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. A major advantage is that sulfonates exhibit significantly better performance with respect to valve clogging and sealing performance. A further advantage is that they are good foaming agents, which significantly improves sealing in vehicle tires. Steric surfactants exhibit good viscosity and foam-regulating properties with respect to the sealant.

[0014] Preferably, the sealant contains two surfactants, with the combined proportion of the first and second surfactants ranging from 0.5 to 2% by weight. Advantageously, the two surfactants can interact with each other and with other components, thus improving the conveying and sealing properties.

[0015] In a further embodiment, the sealant comprises at least one anionic surfactant and at least one non-ionic surfactant, wherein the proportion of the anionic surfactant is preferably in the range of 1.15 to 1.29 wt.% and that of the non-ionic surfactant in the range of 0.3 to 0.45 wt.%. It has proven particularly advantageous that such a proportion leads to improved properties with regard to valve clogging and sealing performance.

[0016] According to the invention, the sealant contains a proportion of rubber latex in the range of 27 wt.% to 46 wt.%, preferably in the range of 32 wt.% to 44 wt.%. A significant advantage of such a latex content is that the latex provides a better seal, allowing the vehicle tire to be reused more quickly and reliably.

[0017] In a further embodiment of the invention, the rubber latex comprises or consists of natural rubber latex (NR latex). The rubber latex can be natural rubber latex (NR) from Hevea brasiliensis or latex from the guayule shrub (Parlhenium argentatum), whereby the natural rubber latex can be used in deprotonated form. Alternatively, it is conceivable that the latex is produced and used synthetically. For this purpose, the use of different latexes in blends, as well as a mixture of NR and synthetic latex, is also conceivable.

[0018] For improved sealing performance and durability, the sealant comprises a resin with a resin content in the range of 2.5 to 12.5 wt.%, preferably in the range of 2.5 to 10 wt.%, and particularly preferably in the range of 4.5 to 10 wt.%. It has been demonstrated that this results in improved properties and also reduces manufacturing costs. The use of natural and / or synthetic resins, such as hydrocarbon resins, is conceivable.

[0019] Preferably, a resin is used which is an aqueous dispersion (emulsion) of up to 60 wt.%, particularly preferably up to 50 wt.%. This means that the proportion of solids in the dispersion, based on the total weight, is up to 60 wt.%, particularly preferably up to 50 wt.%.

[0020] In one embodiment, adhesive resins are used that act as tackifiers. These are, for example, adhesive resins selected from the group consisting of rosin resins and their esters, terpene phenolic resins, alkyne phenolic resins, phenolic resins, and coumaron indene resins. Sealants containing such adhesive resins exhibit particularly high adhesive strength with good sealing properties and have a positive influence on compatibility with other components in the sealant. Rosin resins can be extracted from the resin of various coniferous trees and consist essentially of a mixture of resin acids and terpenes. Furthermore, terpene phenolic resins are those resins produced by acid-catalyzed addition of phenols. Alkyne phenolic resins can be resins whose alkyne is, for example, ethyne, and whose phenolic component is, for example, butylphenol or novolacs made from formaldehyde and, for example, p-tert. Contains butylphenol (or p-diisobutylphenol).Coumaron-indene resins are formed as copolymers during the polymerization of unsaturated compounds contained in the light oil of coal tar.

[0021] The sealant has a resin-to-latex ratio, based on the solids content of latex and resin, in the range of 4 to 40 wt%, particularly in the range of 15 to 32 wt%. Surprisingly, it was shown that with a resin-to-latex ratio below 40 wt%, the probability of valve clogging is reduced and the sealing effect of the aerosol is improved. The effect is even more pronounced below 32 wt%.

[0022] In a further embodiment of the invention, the sealant comprises at least one antifreeze agent, and in particular at least two antifreeze agents, wherein preferably at least one antifreeze agent comprises at least one glycol selected from the group consisting of ethanediol and propanediol. In this case, the antifreeze agent has a low freezing point, which is typically below -10 °C. In combination with water, the freezing point is significantly lower and can reach as low as -55 °C with the correct mixture. Advantageously, the sealant with its low freezing point can be used in colder regions without significantly impairing its pumpability and flow properties. Particularly 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.Furthermore, it is advantageous that the sealant is more environmentally friendly with such an antifreeze agent.

[0023] In a further embodiment of the invention, the total proportion of antifreeze is preferably in the range of 27 to 40 wt.%, wherein, in particular, the proportion of the first antifreeze is in the range of 20 to 25 wt.% and the proportion of the second antifreeze is in the range of 7 to 15 wt.%. Advantageously, this total proportion of antifreeze is optimal for lowering the freezing point of the entire sealant, so that it can also be used at lower temperatures with optimal pumpability and flow properties as well as improved sealing properties.

[0024] In a further embodiment of the invention, the sealant comprises additional additives. For example, aging inhibitors or preservatives can be added to the resin-free sealant to ensure its readiness for use during storage. Furthermore, or additionally, the sealant can contain dispersants and / or emulsifiers and / or pH regulators. A significant advantage is that the resin-free sealant exhibits considerably improved sealing performance.

[0025] In a preferred embodiment, the sealant contains 1 to 2 wt% of at least one aging inhibitor, in particular dispersions of steric and alkylated (poly)phenols and / or alkylated diphenylamines. Advantageously, this extends the shelf life of the sealant.

[0026] In another embodiment, the sealant comprises fillers that contribute to sealing, particularly larger holes. Examples include fibrous materials, especially natural and synthetic fibers, layered silicates, silica, talc, chalk, carbon black, rubber powder, and the like.

[0027] In a further embodiment of the invention, the sealant has a viscosity at 25 °C of 3 to 23 mPa*s, in particular 6 to 16 mPa*s (dynamic viscosity measured on a rheometer, 0.5° cone, 16,000 rpm). This significantly improves the flow properties of the sealant.

[0028] In a further embodiment of the invention, the water content of the resin-free sealant is in the range of 15 to 30 wt.%, particularly in the range of 20 to 25 wt.%. A latex is used that is an aqueous dispersion (emulsion) of up to 85 wt.%, preferably up to 70 wt.%. This means that the solids content in the dispersion, based on the total weight, is up to 85 wt.%, preferably up to 70 wt.%. Alternatively, the solids content in the dispersion, based on the total weight, can be in the range of 85 to 70 wt.%, particularly in the range of 80 to 75 wt.%. Advantageously, the resin-free sealant with such a water and / or solids content is significantly more effective with regard to its sealing properties without the use of a resin.

[0029] Furthermore, the object of the present invention is solved by a sealant container comprising a described sealant, wherein the sealant container has an opening through which the resin-free sealant can be conveyed into a vehicle tire.

[0030] Advantageously, the sealant container according to the invention is easy to use, as the sealant can simply flow out of it. The user can manually press or squeeze the container to deliver the sealant into the vehicle tire. For this purpose, the container must be connected to the vehicle tire valve, for example, via a hose. Alternatively, such a container can be connected to a tire repair kit via a hose. Squeezing the sealant into a tire repair kit is also conceivable, with the kit being designed to generate compressed air using a compressor, which then delivers the sealant into the vehicle tire. A significant advantage is that the sealant container offers better usability with an improved sealant, as the sealant exhibits superior performance with respect to valve clogging and sealing performance.

[0031] The statements and advantages relating to the sealant also apply, vice versa, to the sealant contained in the sealant container.

[0032] In one embodiment of the invention, the sealant container can be connected to a breakdown kit. For this purpose, the sealant container has a connection that can be attached to a breakdown kit, for example, by means of a plug-in or twist-fit mechanism. Advantageously, such a sealant container can be connected to a breakdown kit, which significantly simplifies operation for the user. Furthermore, it has been found that the sealant container, encompassing the sealant, results in a significantly improved performance with regard to valve clogging and sealing performance.

[0033] Furthermore, the object of the present invention is achieved by a method for the temporary sealing of a vehicle tire using at least one described sealant. Such a method makes it easier for the user to seal a vehicle tire, since the sealant's diametrically opposed behavior with respect to valve clogging and sealing performance has been significantly improved.

[0034] The descriptions and advantages relating to the sealant and the sealant container also apply, vice versa, to the method according to the invention.

[0035] In one embodiment of the method according to the invention, the sealant is sprayed through a valve of the vehicle's pneumatic tire. This can be done in particular by means of a tire repair kit, wherein the tire repair kit includes a compressor that generates compressed air. The generated compressed air transports the sealant through a hose into the vehicle tire.

[0036] Furthermore, the invention relates to the use of a described sealant in a puncture repair kit for a vehicle pneumatic tire.

[0037] Further advantages and features of the resin-free sealant, the sealant container, and the method according to the invention will become apparent from the description and the dependent claims, which relate to advantageous embodiments of the present invention and are not to be understood as limiting. The invention also encompasses combinations of features from different dependent claims, even if the dependent claims do not relate to each other or if they belong to different claim categories. Furthermore, combinations of preferred and particularly preferred embodiments can also be combined with one another. This also applies to the individual features of the exemplary embodiments discussed below, insofar as these are not obviously related to one another by a person skilled in the art.

[0038] The following substances were used in accordance with the invention, although the invention is not limited to these. These substances are merely examples: Natural rubber latex: 60 wt% solids content, LATZ natural latex, e.g., Weber & Schaer. Adhesive resin: rosin ester, 50 wt% solids content, Tacolyn, Eastman Chemical Company and / or aromatically modified terpene resin, Nanolet TO, Yasuhara Chemical Co. Ltd. Anionic surfactant: anionic disulfonate, 51 wt% active solids content. Steric surfactant: sodium trialkylphenol polyethylene glycol ether sulfate, 25 wt% active solids content.

Claims

1. Sealant for temporary sealing of pneumatic vehicle tyres, characterized in that the sealant contains a proportion of 27% to 46% by weight of a rubber latex, a proportion of 2.5% to 12.5% by weight of a resin and a surfactant, wherein the solids content of the resin based on the solids content of latex and resin is in the range from 4% to 40% by weight and wherein the solids content of the surfactant is in the range from 6.5% to 12% by weight based on the solids content of the rubber latex.

2. Sealant according to Claim 1, characterized in that the solids content of the surfactant is in the range from 7% to 11% by weight, especially in the range from 8% to 10% by weight.

3. Sealant according to Claim 1 or 2, characterized in that the at least one surfactant comprises a block copolymer of propylene oxide and ethylene oxide, wherein the proportion of ethylene oxide is preferably 40% by weight.

4. Sealant according to any of the preceding claims, characterized in that the sealant comprises at least one anionic surfactant and at least one non-ionic surfactant, wherein the proportion of the anionic surfactant is preferably in the range from 1.15% to 1.29% by weight and that of the non-ionic surfactant is in the range from 0.3% to 0.45% by weight.

5. Sealant according to any of the preceding claims, characterized in that the sealant comprises a proportion of rubber latex in the range from 32% to 44% by weight.

6. Sealant according to any of the preceding claims, characterized in that the sealant comprises at least one antifreeze, especially at least two antifreezes, wherein especially at least one antifreeze comprises at least one glycol selected from the group consisting of ethanediol and propanediol.

7. Sealant container comprising a sealant according to any of the preceding claims, characterized in that the sealant container comprises an opening through which the sealant is conveyable into a vehicle tyre.

8. Use of a sealant according to any of Claims 1 to 6 or of a sealant container according to Claim 7 for temporary sealing of a pneumatic vehicle tyre.

9. Tyre repair kit comprising the sealant container according to Claim 7.