Self-sealing tire sealant, process for producing same, pneumatic vehicle tire containing said tire sealant, and use of a dispersion of crosslinker in a plasticizer in the production of a tire sealant

Abstract

The present invention relates to a self-sealing tire sealant, a method for its preparation, and a vehicle pneumatic tire comprising the tire sealant. The present invention further relates to the use of a dispersion of a crosslinking agent in a plasticizer in the preparation of a tire sealant. The crosslinking agent is added to the tire sealant during its preparation as a dispersion of at least one plasticizer and at least one crosslinking agent.

Description

[Technical field]

[0001] The present invention relates to a self-sealing tire sealant, a process for making the same, and a pneumatic vehicle tire containing the tire sealant.

[0002] The present invention further relates to the use of the dispersion of crosslinker in plasticizer in the preparation of a tire sealant. [Background technology]

[0003] Self-sealing pneumatic tires for vehicles are known, for example, from the applicant's DE 10 2006 059 286 A1, where a standard tire construction is subsequently provided with a sealant layer. The self-sealing sealant is a self-adhesive, viscous sealing compound that is applied as a layer from the radially inner side in the projecting area of ​​the belt package up to the radially innermost tire layer, the substantially airtight inner layer. The sealant layer can automatically seal punctures up to 5 millimeters in diameter. In the event of a puncture penetrating the tread through the inner layer, the sealant completely surrounds the penetrating foreign object, seals the inner side from the environment and thus prevents compressed air from being lost from the tire. The driver of the vehicle does not have to immediately exchange the defective tire for an equivalent replacement wheel or an emergency wheel.

[0004] The sealant is characterized by high air tightness, high adhesion and balanced flow properties.

[0005] Other self-sealing tire sealants are disclosed, for example, in WO 2020 / 169234 A1 and EP 3546202 B1. According to the disclosures in these documents, the sealants may contain cross-linking chemicals, such as cross-linking agents and cross-linking initiators. In the case of such fine chemicals, the challenge is to achieve the best possible distribution thereof among the other components of the tire sealant.

[0006] For this purpose, EP 3546202 B1 discloses the addition of peroxides as crosslinking initiators in a mixture of organic solvents during the production of the sealant.

[0007] However, organic solvents have the disadvantage that they are volatile and have adverse health effects, particularly respiratory tract irritation.

[0008] Crosslinking agents, particularly quinonedioxime compounds such as p-benzoquinonedioxime, are added as powders in the manufacture of prior art sealants, as disclosed, for example, in EP 3009260 A1. However, such powdered materials are explosive, thus making the handling and thus the manufacture of the sealant much more difficult.

[0009] Powdered crosslinking agents such as p-benzoquinone dioxime also present great difficulties in dispersing them homogeneously, especially since they are typically present in small amounts relative to the total mass of the sealant.

[0010] An inhomogeneous distribution of the crosslinker in the sealant leads to inhomogeneous crosslinking and thus to undesirable properties, especially poor creep behavior and low elasticity, which therefore adversely affect processability and sealing effect. In the worst case, this may even result in the sealant flowing out of the tire. Summary of the Invention [Problem to be solved by the invention]

[0011] The object of the present invention is therefore to provide a self-sealing tire sealant comprising at least one crosslinking agent, which exhibits improved creep behavior and higher elasticity. The tire sealant therefore exhibits better processability during manufacture and application in pneumatic vehicle tires, and achieves improved sealing effect therein. Unwanted runoff of the tire sealant from the tire is also avoided.

[0012] The tire sealant shall be produced in a manner that is as environmentally friendly as possible, has no adverse health effects, and is easier to manufacture.

[0013] It is a further related object of the present invention to provide a pneumatic vehicle tire including a tire sealant that overcomes the aforementioned problems of manufacture and sealing effectiveness. [Means for solving the problem]

[0014] The object is achieved by an inventive tire sealant according to claim 1, by a process according to the invention for producing a tire sealant comprising at least one crosslinking agent and by the use according to the invention of a dispersion of a crosslinking agent in a plasticizer in the production of a tire sealant comprising at least one crosslinking agent. The object is further achieved by a pneumatic vehicle tire according to the invention which comprises a tire sealant according to the invention.

[0015] Surprisingly, it has been found that when at least one crosslinking agent is added as a dispersion of at least one plasticizer and at least one crosslinking agent during the production of the tire sealant, the distribution and homogeneity of the crosslinking agent in the tire sealant is significantly improved.The tire sealant according to the present invention shows higher elasticity and better creep behavior.The tire sealant also shows an improved sealing effect, which in particular avoids the flow-out of the sealant from the tire.

[0016] The tire sealant according to the invention is characterized by increased durability, especially after a puncture has occurred.

[0017] The sealant according to the invention and the tire according to the invention are produced in a manner that is as environmentally friendly and healthy as possible.

[0018] For the sake of brevity, the terms "self-sealing tire sealant" and "sealant" are used synonymously unless otherwise specifically stated in the context of the present invention.

[0019] Moreover, for the sake of brevity, the terms "pneumatic vehicle tire" and "tire" are used synonymously unless otherwise stated in the context of this invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The components of the sealant according to the invention will now be described in more detail. Any indication including any preference level and embodiment feature of the sealant also applies to the process according to the invention for producing the sealant and to the pneumatic vehicle tire according to the invention, unless expressly stated otherwise, including in terms of the combination of any preference level and embodiment feature of the sealant with any preference level and embodiment feature of the process and tire. Furthermore, any indication including any preference level and embodiment feature also applies to the use according to the invention.

[0021] All resulting combinations of features are encompassed by the present invention.

[0022] The present invention further includes all combinations of the various features of the sealant with the same or different desirability levels.

[0023] The amounts given in % by weight of the components of the sealant are in each case based on the total amount of the sealant, unless expressly stated otherwise.

[0024] The amounts given in % by weight of the components of the dispersion, especially for the crosslinker and plasticizer, are based on the total amount of the dispersion.

[0025] In accordance with the present invention, at least one crosslinking agent is added to the tire sealant during its manufacture as a dispersion of at least one plasticizer and the at least one crosslinking agent.

[0026] The tire sealants, crosslinkers and plasticizers may in principle be of any type suitable for pneumatic vehicle tires and known to those skilled in the art.

[0027] The plasticizer may be any plasticizer known to those skilled in the art, in particular oil, such as vegetable oil, in particular rapeseed oil, aromatic, naphthenic or paraffinic mineral oil plasticizer, such as MES (light extractive solvates) or paraffin oil (white mineral oil) or RAE (residual aromatic extract) or TDAE (treated distillate aromatic extract) or rubber-to-liquid oil (RTL) or biomass-to-liquid oil (BTL), preferably with a polycyclic aromatic content of less than 3% by weight according to the IP 346 method. Mineral oil is particularly preferred as plasticizer.

[0028] The plasticizer of the dispersion is preferably an oil, which is preferably selected from the group consisting of paraffin oil, MES (mild emulsion solvate) (paraffinic MES is particularly preferred), and vegetable oil (rapeseed oil is particularly preferred).

[0029] The oil as plasticizer realizes a particularly good distribution of the crosslinking agent in the plasticizer and thus the dispersion in the tire sealant.At the same time, oil, especially selected from the group consisting of paraffin oil, MES (mild solvate) (particularly preferred is paraffinic MES) and vegetable oil (particularly preferred is rapeseed oil), is particularly suitable for such tire sealant, and they are characterized by excellent properties in terms of sealing effect, flow behavior and adhesion.

[0030] Oils, especially those selected from the group consisting of paraffin oil, MES (mild solvates) (paraffinic MES is especially preferred), and vegetable oils (rapeseed oil is especially preferred), are also relatively environmentally friendly, do not pose adverse health effects, and do not tend to evaporate early like organic solvents.

[0031] In a particularly advantageous embodiment, the oil is a paraffinic mineral oil, in particular a paraffin oil.

[0032] The crosslinking agent is preferably selected from the group consisting of quinone dioxime compounds, quinone, divinylbenzene, and 1,4-dinitrosobenzene, with quinone dioxime compounds, especially p-benzoquinone dioxime (QDO), being particularly preferred.

[0033] This makes it possible to achieve particularly good crosslinking of the sealant and therefore excellent properties in terms of sealing effect and flow behavior.

[0034] The dispersion is 50% to 80% by weight of a crosslinker; 20% to 50% by weight of plasticizer It is preferred that the formula (I) includes:

[0035] The dispersion may optionally contain other ingredients, such as chalk. The dispersion preferably contains up to 5% by weight of other ingredients.

[0036] In an advantageous embodiment, the dispersion is free of other components, ie it contains 0% by weight of other components.

[0037] The amounts listed in weight percent are based on the total weight of the dispersion.

[0038] The dispersion is 60% to 70% by weight, for example 65% by weight, of a crosslinker; 30% to 40% by weight, e.g. 35% by weight, of a plasticizer, and optionally up to 5% by weight of other components, e.g. chalk. It is particularly preferred that the composition comprises:

[0039] In an advantageous embodiment, the dispersion is free of other components, ie it contains 0% by weight of other components.

[0040] The amounts listed in weight percent are based on the total weight of the dispersion.

[0041] In a preferred embodiment, the dispersion comprises 60% to 70% by weight, for example 65% by weight, of p-benzoquinone dioxime (QDO); 30% to 40% by weight, for example 35% by weight, of an oil, preferably a paraffinic mineral oil, in particular a paraffin oil Includes.

[0042] In an advantageous embodiment, the dispersion is free of other components, ie it contains 0% by weight of other components.

[0043] The amounts listed in weight percent are based on the total weight of the dispersion.

[0044] The component amounts of the dispersions described are understood to equal 100% by weight and are selected as such.

[0045] The object underlying the present invention is particularly easily achieved by the preferred and especially preferred amounts of crosslinker and plasticizer.

[0046] In particular there is a homogeneous distribution of the crosslinking agent in the sealant, which is characterized by high elasticity as a result of the improved degree and homogeneity of crosslinking.

[0047] The self-sealing tire sealant preferably has d) 0.5% to 7% by weight, particularly preferably 1.5% to 5% by weight, of a dispersion of at least one plasticizer and at least one crosslinker, the amounts in % by weight being based here on the total amount of the tire sealant.

[0048] It is preferred if the self-sealing tyre sealant is based on the crosslinking of at least one polyolefin and / or rubber with at least one crosslinking agent.

[0049] This ensures a particularly high compatibility of the sealant with pneumatic vehicle tires, in particular with their inner layers, and at the same time such sealants can be particularly easily adapted to the different requirements of different types of tires, so that in each case unique characteristics are obtained with regard to the sealing effect, flow behavior and adhesion.

[0050] In an advantageous embodiment, the sealant comprises at least one rubber.

[0051] The rubber may be selected from any type of rubber known to those skilled in the art. Mixtures of different rubbers are also contemplated.

[0052] In a preferred embodiment of the invention, the rubber is natural rubber (NR) and / or butadiene rubber (BR) and / or isoprene rubber (IR) and / or styrene butadiene rubber (SBR) and / or polychloroprene (CR) and / or butyl rubber (IIR) and / or bromobutyl rubber (BIIR) and / or black butyl rubber (CIIR) and / or silicone rubber.

[0053] These types of rubbers are particularly well suited to the processing temperatures during manufacture of the sealant and its subsequent use, particularly in pneumatic vehicle tires.

[0054] It is particularly preferred if the self-sealing tire sealant comprises at least one butyl rubber (IIR). As known to those skilled in the art, butyl rubber is a copolymer of isobutene and isoprene.

[0055] The butyl rubber present in the sealant preferably has an isoprene content of 0.5-5 mol %. The skilled person will understand that the isoprene content also represents the proportion of unsaturated carbon-carbon bonds in the polymer chains in the butyl rubber. The higher the isoprene content, the higher the crosslinking capacity of the rubber in the sealant and thus of the polymer matrix due to the increased proportion of unsaturated bonds.

[0056] In a preferred embodiment, the sealant comprises a butyl rubber having an isoprene content of 2.3 to 5.0 mol %.

[0057] This relatively high isoprene percentage allows for a higher level of crosslinking and improved hermeticity.

[0058] At the same time, this may necessitate increased amounts of crosslinker and optionally crosslinking initiator, especially in cases where the crosslinking chemicals are inhomogeneously distributed, and / or where the increased isoprene content of the butyl rubber results in inhomogeneous distribution of the crosslinker.

[0059] Due to the dispersion of crosslinker and plasticizer and the resulting more homogeneous distribution of crosslinker in the sealant, the present invention also makes it possible to utilize butyl rubber with an isoprene content of 2.3-5.0 mol % and the associated benefits.

[0060] The present invention therefore makes it possible to exploit the full crosslinking capacity realized by the presence of butyl rubber having an isoprene content of 2.3 to 5.0 mol %.

[0061] A more homogenous distribution in the dispersion means that it may not be necessary to use larger amounts of crosslinker, or the amount of crosslinker can be matched exactly to the isoprene content, so that neither crosslinker nor unsaturated bonding sites on the polymer chains are wasted.

[0062] The self-sealing tire sealant preferably comprises: a) It contains 9% by weight to 50% by weight, particularly preferably 12% by weight to 50% by weight, of at least one rubber, which is preferably butyl rubber (IIR).

[0063] In a particularly preferred embodiment, the sealant a) comprises 20.5% to 40% by weight, particularly preferably 20.5% to 29.5% by weight, of at least one butyl rubber.

[0064] The sealant therefore has a particularly good property profile, including sealing effect, flow behavior and adhesion, and in particular very good airtightness. Such a relatively large amount of butyl rubber in the sealant has the advantage that, at the same time, accelerated crosslinking and improved airtightness are realized when using butyl rubbers whose isoprene content is between 2.3 and 5.0 mol %.

[0065] In an advantageous embodiment, the sealant comprises at least one polyolefin.

[0066] This results in optimal flow behavior and associated high manufacturing efficiency (processability) of the sealant.

[0067] The at least one polyolefin preferably has a number average molecular weight distribution Mn according to GPC of 400 to 2500 g / mol, particularly preferably 800 to 2500 g / mol, very particularly preferably 800 to 1600 g / mol, also preferably 1200 to 1600 g / mol, also particularly preferably 1200 to 1400 g / mol, for example 1300 g / mol.

[0068] Polyolefins having Mn in the above ranges are particularly suitable for achieving the desired flowability and sealing effect of the sealant when a puncture occurs.

[0069] The term "polyolefins" is understood to mean in particular the polyalkenes obtained by polymerization of unbranched alkenes, such as polyethylene, polypropylene, polybutene and polyisobutene.

[0070] The at least one polyolefin is particularly preferably at least one polybutene.

[0071] This establishes the tack of the finished sealant and determines its flowability during the manufacturing process as well as its local consistency in the finished sealant.

[0072] The at least one polyolefin may also be a mixture of two or more polybutenes, each having a Mn of 400 to 2500 g / mol, and these polybutenes may differ in their Mn.

[0073] Suitable polybutenes, also known as polybutylenes, are available, for example, under the trade name Indopol® polybutene from INEOS Capital Limited.

[0074] Mixtures of at least one polybutene with at least one other polyolefin are also contemplated.

[0075] The self-sealing tire sealant preferably comprises: b) Contains 11% to 80% by weight of at least one polyolefin, the polyolefin being preferably polybutene.

[0076] In a particularly advantageous embodiment, the sealant comprises b) 14.5% to 65% by weight of at least one polyolefin.

[0077] The sealant may further comprise components such as crosslinking initiators, fillers, tackifiers, additional plasticizers, such as oils, and optionally other additives, such as color pigments and / or zinc oxide and / or sulfur, among others.

[0078] In a preferred embodiment of the invention, the sealant comprises at least one filler, in particular at least one active filler.

[0079] The filler is preferably selected from carbon black and silicon dioxide.

[0080] The silicon dioxide is preferably amorphous silicon dioxide, for example precipitated silica, also called precipitated silicon dioxide. However, it is also possible to use, for example, finely divided silicon dioxide, instead.

[0081] The filler is particularly preferably carbon black.

[0082] Suitable carbon blacks include all kinds of carbon black types known to those skilled in the art. It is preferred if the carbon black is selected from technical carbon black and pyrolytic carbon black, with technical carbon black being more preferred.

[0083] This has the advantage that the cohesion of the sealant is improved and the sealant becomes less tacky during the manufacturing process. The constancy and tear properties of the sealant are improved at the same time.

[0084] In an advantageous embodiment of the present invention, carbon black is used which has an iodine adsorption number according to ASTM D1510 of 20 to 180 g / kg, particularly preferably 30 to 140 g / kg, and a DBP number according to ASTM D2414 of 30 to 200 mL / 100 g, preferably 90 to 180 mL / 100 g, particularly preferably 110 to 180 mL / 100 g.

[0085] In another preferred embodiment of the present invention, N326 type carbon black is used.

[0086] Mixtures of two or more carbon blacks are also contemplated.

[0087] The self-sealing tire sealant preferably comprises: c) 2% to 15% by weight of at least one filler, the filler being preferably selected from carbon black and silicon dioxide, with carbon black being particularly preferred.

[0088] With the above mentioned amounts the sealant exhibits very good constancy due to optimized creep behavior, very good sealing effect and very good tear properties.

[0089] In a preferred embodiment of the invention, the sealant comprises at least one crosslinking initiator.

[0090] A crosslinking initiator is a chemical that initiates the crosslinking of the sealant.

[0091] The at least one crosslinking initiator is preferably selected from the group consisting of lead oxides, other metal oxides, and peroxides, with peroxides being particularly preferred.

[0092] The peroxide is preferably selected from the group consisting of diaroyl peroxides, diacyl peroxides, and peroxyesters.

[0093] The crosslinking initiator may be added either as a pure substance or in admixture with a stabilizer such as dibutyl maleate.

[0094] For example, a mixture of 50% by weight dibenzoyl peroxide and 50% by weight dibutyl maleate is contemplated.

[0095] It is furthermore conceivable to add a crosslinking initiator to the liquid in a weight fraction of 35% to 40% by weight, as described in EP 3546202 B.

[0096] In all mixtures, only the amount of peroxide present is included in the above-mentioned amount of crosslinking initiator in the sealant, i.e., the above-mentioned amount of at least one crosslinking initiator does not include any accompanying substances such as dibutyl maleate or liquids.

[0097] The self-sealing tire sealant preferably comprises: e) 0.5% to 8% by weight, preferably 0.5 to 6% by weight, of at least one crosslinking initiator Includes.

[0098] The combination of the crosslinker and crosslink initiator in the amounts described above provides a particularly effective tire sealant that seals quickly in the event of a puncture and can be further optimized for tires having different internal pressures.

[0099] In an advantageous embodiment, in particular in cases where the sealant does not already show sufficient adhesion due to the components present, in particular the polymers, the sealant comprises at least one adhesive agent. The term "adhesive agent" is understood in principle to mean any substance which increases the adhesion of the sealant.

[0100] In an advantageous embodiment of the invention, the tackifier is at least one hydrocarbon resin.

[0101] As will be appreciated by those skilled in the art, a hydrocarbon resin is a polymer made up of monomers, where the hydrocarbon resin is formally made up of derivatives of the monomers by bonding them together.

[0102] The term "hydrocarbon resin", in the context of this application, includes resins containing carbon and hydrogen atoms and, optionally, heteroatoms such as, inter alia, oxygen atoms.

[0103] The hydrocarbon resin is preferably selected from the group consisting of phenolic resins, further aromatic resins, preferably alpha-methylstyrene-styrene resins and / or chroman-indene resins, aliphatic resins, preferably C5 resins, and rubber resins, in particular rosin and / or balsam resins. The adhesive is particularly preferably a fatty acid C5 resin.

[0104] The self-sealing tire sealant preferably comprises: f) 1.5% to 10% by weight of at least one adhesive Includes.

[0105] Such an amount optimizes the adhesion and viscosity of the sealant.

[0106] Self-sealing tire sealant g) It is preferred if it also contains up to 1.1% by weight, particularly 0.1 to 1.1% by weight, of zinc oxide.

[0107] Zinc oxide improves the stability of the crosslinking sites in terms of lifetime and with respect to heat.

[0108] In an advantageous embodiment, the self-sealing tire sealant also comprises at least one additional plasticizer in order to further optimize the sealant, especially with regard to its processability, depending on the composition of its other components.

[0109] The additional plasticizer may be any plasticizer known to those skilled in the art, in particular preferably oil, in particular aromatic, naphthenic or paraffinic mineral oil plasticizer, such as MES (light extractive solvates) or RAE (residual aromatic extract) or TDAE (distillate aromatic extract) or rubber-to-liquid oil (RTL) or biomass-to-liquid oil (BTL) having a polycyclic aromatic content of less than 3% by weight according to the IP 346 method. Mineral oil is particularly preferred as plasticizer.

[0110] If a mineral oil is used, it is preferably selected from the group consisting of DAE (distillate aromatic extract), RAE (residual aromatic extract), TDAE (treated distillate aromatic extract), MES (light extract solvate), and naphthenic oils.

[0111] Particular preference is given to using MES (mild extractive solvates) as additional plasticizer, with paraffinic MES (mild extractive solvates) also being particularly preferred here.

[0112] In a preferred embodiment, the self-sealing tire sealant comprises: h) 0.5% to 8% by weight of oil as an additional plasticizer Includes.

[0113] In a further preferred embodiment, the self-sealing tire sealant does not contain any additional plasticizers besides those already present in the dispersion, i.e. 0 wt. % additional plasticizer.

[0114] In an advantageous embodiment, the addition of a dispersion of crosslinker in a plasticizer according to the invention therefore makes it possible at the same time to avoid the addition of additional plasticizer.

[0115] This eliminates the need to measure and add additional ingredients.

[0116] The self-sealing tire sealant also contains up to 1% by weight of sulfur, especially 0.1% to 1.0% by weight.

[0117] This improves the high temperature stability of the environmental site.

[0118] In a preferred embodiment, the sealant therefore comprises the following components: butyl rubber, polyolefin, filler, a dispersion of crosslinker and plasticizer, crosslinking initiator, tackifier, filler, and optionally further plasticizer, zinc oxide, and sulfur. Includes.

[0119] All indications and preferred characteristics of any preference level apply to ingredient types and amounts.

[0120] In particularly preferred embodiments, the sealant comprises components according to the specified characteristics a) to i) in combination with one another. All indications and preferred characteristics at all preference levels apply to types and amounts of components.

[0121] In a particularly advantageous embodiment of the present invention, the self-sealing tire sealant comprises at least the following components: a1) 12% to 22% by weight of at least one rubber, preferably a butyl rubber, the isoprene content of the butyl rubber being preferably 0.5 to 2.3 mol%; b1) 58% to 78% by weight of at least one polyolefin; c1) 4% to 8% by weight of at least one filler; d1) a dispersion of 0.5% to 2.5% by weight of at least one plasticizer and at least one crosslinker, the dispersion comprising 50% to 80% by weight of the crosslinker and 20% to 50% by weight of the plasticizer; e1) 1.5% to 3.5% by weight of at least one crosslinking initiator; f1) 1.5% by weight to 4.5% by weight of at least one adhesive; Includes.

[0122] The sealant further: g1) 0.3% to 1.1% by weight of zinc oxide; h1) 0.5% to 2.5% by weight of oil; Optionally, i1) up to 0.6% by weight of sulfur, in particular 0.1% to 0.6% by weight of sulfur; Includes.

[0123] Such sealants having compositions a1) to i1) are particularly suitable for passenger car tyres.

[0124] One embodiment of the invention is a passenger tire comprising a sealant having compositions a1)-i1) on at least the inner surface opposite the threads.

[0125] The above mentioned characteristics regarding type and, optionally, amounts, including all embodiments and preference levels, also apply to components a1) to i1).

[0126] For example, among the component, "b1) 58% to 78% by weight of at least one polyolefin," the polyolefin is preferably polybutene.

[0127] In another particularly advantageous embodiment of the present invention, the self-sealing tire sealant comprises the following components: a2) 13.5% by weight to 29.5% by weight, preferably 20.5% by weight to 29.5% by weight, of at least one rubber, preferably a butyl rubber, the butyl rubber having an isoprene content preferably of 0.5 to 2.3 mol%, b2) 47% to 77% by weight of at least one polyolefin; c2) 2.5% to 7.5% by weight of at least one filler; d2) a dispersion of 1% to 4% by weight of at least one plasticizer and at least one crosslinker, the dispersion comprising 50% to 80% by weight of crosslinker and 20% to 50% by weight of plasticizer; e2) 2% to 4% by weight of at least one crosslinking initiator; f2) 1.5% to 4.5% by weight of at least one adhesive; Includes.

[0128] This sealant further: Optionally, g2) up to 1.0 wt. % zinc oxide, in particular 0.1 wt. % to 1.0 wt. % zinc oxide; Optionally, h2) up to 4 wt. % oil, in particular 0.5 wt. % to 4 wt. % oil; Optionally, i2) up to 1.0 wt. % sulfur, in particular 0.1 wt. % to 1.0 wt. % sulfur; It is preferred that the formula (I) includes:

[0129] Such sealants having compositions a2) to i2) are particularly suitable for van tyres.

[0130] One embodiment of the invention is a van tire comprising a sealant having compositions a2) to i2) at least on the inner surface opposite the threads.

[0131] All the above mentioned features regarding type and, optionally, also amounts, including all embodiments and levels of preference, also apply to components a2) to i2).

[0132] In another particularly advantageous embodiment of the present invention, the self-sealing tire sealant comprises at least the following components: a3) 15.5% by weight to 35.5% by weight of at least one rubber, preferably a butyl rubber, the butyl rubber preferably having an isoprene content of 0.5 to 5 mol%; b3) 40% to 70% by weight of at least one polyolefin; c3) 2.5% to 7.5% by weight of at least one filler; d3) a dispersion of 2% to 5% by weight of at least one plasticizer and at least one crosslinker, the dispersion comprising 50% to 80% by weight of crosslinker and 20% to 50% by weight of plasticizer; e3) 2.5% to 5.5% by weight of at least one crosslinking initiator; f3) 1.5% by weight to 5.5% by weight of at least one adhesive; Includes.

[0133] This sealant further: Optionally, g3) up to 1.0 wt. % zinc oxide, in particular 0.1 wt. % to 1.0 wt. % zinc oxide; Optionally, h3) up to 5 wt. %, in particular 0.5 wt. % to 5 wt. % of oil; and Optionally, i3) up to 1.0 wt. % sulfur, in particular 0.1 wt. % to 1.0 wt. % sulfur; It is preferred that the formula (I) includes:

[0134] Such sealants having compositions a3) to i3) are particularly suitable for truck tyres.

[0135] One embodiment of the invention is a truck tire comprising a sealant having compositions a3)-i3) at least on the inner surface opposite the threads.

[0136] The above mentioned characteristics regarding type and, optionally, amounts, including all embodiments and preference levels, also apply to components a3) to i3).

[0137] In another particularly advantageous embodiment of the present invention, the self-sealing tire sealant comprises at least the following components: a4) 26% to 50% by weight of at least one rubber, preferably a butyl rubber, the butyl rubber preferably having an isoprene content of 0.5 to 5 mol%, b4) 14.5% to 54.5% by weight of at least one polyolefin; c4) 3% to 9% by weight of at least one filler; d4) a dispersion of 3% to 7% by weight of at least one plasticizer and at least one crosslinker, the dispersion comprising 50% to 80% by weight of crosslinker and 20% to 50% by weight of plasticizer; e4) 4% to 8% by weight of at least one crosslinking initiator; f4) 2% by weight to 7% by weight of at least one adhesive; Includes.

[0138] This sealant further: Optionally, g4) up to 1.0 wt. % zinc oxide, in particular 0.1 wt. % to 1.0 wt. % zinc oxide; h4) 2% to 8% by weight of oil; Optionally, i4) up to 1.0 wt. % sulfur, in particular 0.1 wt. % to 1.0 wt. % sulfur; It is preferred that the formula (I) includes:

[0139] Such sealants with compositions a4) to i4) are particularly suitable for agricultural or construction site tyres, such as agricultural tractors, self-propelled harvesters, trailers, wheel loaders or excavators.

[0140] One embodiment of the invention is an agricultural or construction tire comprising a sealant having compositions a4) to i4) at least on the inner surface opposite the threads.

[0141] The above mentioned characteristics regarding type and, optionally, also amounts, including all embodiments and preference levels, also apply to components a4) to i4).

[0142] In addition, as reiterated above, all other indications regarding these characteristics also apply to compositions a1)-i1), a2)-i2), a3)-i3), and a4)-i4).

[0143] This therefore applies in particular to all of the above embodiments in which the polyolefin is polybutene, the filler is carbon black, the tackifier is a hydrocarbon resin, the crosslinking initiator is a peroxide, etc.

[0144] This is especially true for all of the above embodiments, where the plasticizer is preferably an oil, particularly preferably selected from the group consisting of paraffin oil, MES (mild extractive solvates) (paraffinic MES is particularly preferred), and vegetable oil (rapeseed oil is particularly preferred).

[0145] In a particularly advantageous embodiment, the oil is a paraffinic mineral oil, in particular a paraffin oil.

[0146] This is especially true for all of the above-mentioned embodiments in which the cross-linking agent is selected from the group consisting of quinonedioxime compounds, quinones, divinylbenzene, and 1,4-dinitrosobenzene, with quinonedioxime compounds, and in particular, p-benzoquinonedioxime (QDO), being particularly preferred.

[0147] The process according to the invention for producing a self-sealing tire sealant comprising at least one crosslinking agent comprises at least the following process steps: X1) producing or providing a dispersion of at least one crosslinker in at least one plasticizer; X2) providing further components, such as preferably at least one polyolefin and / or at least one rubber, in one or more process steps; X3) adding the dispersion from step X1) to the components of step X2); Includes.

[0148] The dispersion of step X1) is commercially available, for example a dispersion of 60% to 65% by weight of p-benzoquinone dioxime and 35% to 40% by weight of oil, optionally containing up to 5% by weight of chalk, available from LORD Germany Feinchemie GmbH under the trade name QDO 65MK.

[0149] If the dispersion of step X1) is not commercially available, it can be prepared as follows. X01) providing at least one crosslinking agent, the crosslinking agent being selected from the group consisting of quinone dioxime compounds, quinone, divinylbenzene, and 1,4-dinitrosobenzene, with quinone dioxime compounds and, in particular, p-benzoquinone dioxime (QDO) being particularly preferred; X02) at least one plasticizer is provided, the plasticizer being preferably selected from the group consisting of paraffin oil, MES (mild extractive solvates) (paraffinic MES is particularly preferred), and vegetable oil (rapeseed oil is particularly preferred); X03) The crosslinker from step X01) is dispersed intensively with the plasticizer from step X02) to obtain a dispersion of at least one crosslinker in at least one plasticizer.

[0150] In an exemplary and advantageous embodiment of the invention, process step X2) comprises at least the following process steps: X2-1) mixing at least one rubber with at least one filler to form a masterbatch; X2-2) mixing the masterbatch with at least one polyolefin to produce component A; X2-3) mixing at least one crosslinking initiator with at least one polyolefin to produce component B; X2-4) mixing component A and component B to form a tire sealant; Includes.

[0151] The addition of the dispersion according to step X3) is preferably carried out during step X2-1).

[0152] Mixing of the ingredients in all of the steps is carried out in equipment known to those skilled in the art.

[0153] The mixing in step X2-2) is preferably carried out in an extruder, preferably a twin screw extruder.

[0154] The mixing in step X2-3) is preferably carried out in a mixing tank.

[0155] The mixing in step X2-4) is preferably carried out in a static mixer.

[0156] As previously mentioned, the present invention further provides a pneumatic vehicle tire comprising a tire sealant according to the present invention, the tire sealant including all of the above indicia on at least the inner surface opposite the treads.

[0157] As mentioned above, the present invention further provides the use of a dispersion of at least one crosslinker, preferably p-benzoquinone dioxime, in at least one plasticizer, preferably selected from the group consisting of paraffin oil, MES (mild extractive solvate) (paraffinic MES is particularly preferred), and vegetable oil (rapeseed oil is particularly preferred), in the manufacture of a self-sealing tyre sealant.

[0158] The present invention will now be more particularly described with reference to exemplary embodiments.

[0159] Table 1 shows the hysteresis and creep behavior in terms of average loss tangent values ​​at 100° C. of the inventive sealant E1 and the comparative sealant V1.

[0160] The amounts of the components shown are specified in weight percent. E1 was prepared using the process according to steps X1) to X3) described above including X2-1) to X2-4), where the dispersion was added in step X2-1). V1 was prepared according to steps X2-1) to X-2-4), where the crosslinker was added in step X2-1).

[0161] The following methods were used to characterize the properties: Average loss tangent by frequency transmission at 100℃ Vertical creep: Measured creep length: Length in millimeters (mm) of creep-induced sample after vertical creep at 125°C

[0162] Loss tangent and creep length values ​​were determined by averaging two samples each.

[0163] [Table 1]

[0164] As is evident from Table 1, the sealant of the present invention provides a lower loss tangent at 100°C.

[0165] E1 also exhibits improved, ie, reduced, creep behavior.

[0166] This improves the processability of the sealant during its manufacture and application in pneumatic vehicle tires, while preventing, or at least significantly reducing, any undesirable runoff of the sealant from the tire.

Claims

1. 1. A self-sealing tire sealant comprising at least one crosslinking agent, characterized in that said at least one crosslinking agent is added to said tire sealant during its manufacture as a dispersion of at least one plasticizer and said at least one crosslinking agent.

2. 2. The self-sealing tyre sealant according to claim 1, characterized in that the plasticizer is an oil, preferably selected from the group consisting of paraffin oil, MES (Mild Extraction Solvates), with paraffinic MES being particularly preferred, and vegetable oil, with rapeseed oil being particularly preferred.

3. The crosslinking agent is selected from the group consisting of quinone dioxime compounds, quinones, divinylbenzene, and 1,4-dinitrosobenzene, and is particularly preferably selected from the group consisting of quinone dioxime compounds and 3. Self-sealing tyre sealant according to claim 1 or 2, characterized in that p-benzoquinone dioxime is particularly preferred.

4. 4. A self-sealing tyre sealant according to any one of claims 1 to 3, characterised in that the dispersion comprises 50% to 80% by weight, preferably 60% to 70% by weight, of crosslinker and 20% to 50% by weight, preferably 30% to 40% by weight, of plasticiser, the amounts indicated in % by weight being based on the total amount of the dispersion.

5. Self-sealing tyre sealant according to any one of claims 1 to 4, characterised in that it is based on crosslinking of at least one polyolefin and / or rubber with said at least one crosslinking agent.

6. a) 9% to 50% by weight, preferably 12% to 50% by weight, particularly preferably 20.5% to 40% by weight, of at least one rubber, preferably butyl rubber (IIR), the butyl rubber preferably having an isoprene content of 0.5 to 5 mol %. The self-sealing tire sealant according to any one of claims 1 to 5, characterized in that it comprises

7. b) 11% to 80%, preferably 14.5% to 65%, by weight of at least one polyolefin, preferably polybutene The self-sealing tire sealant according to any one of claims 1 to 6, characterized in that it comprises

8. c) 2% to 15% by weight of at least one filler, preferably selected from carbon black and silicon dioxide, with carbon black being particularly preferred. The self-sealing tire sealant according to any one of claims 1 to 7, characterized in that it comprises

9. d) 0.5% to 7% by weight, preferably 1.5% to 5% by weight, of said dispersion of at least one plasticizer and said at least one crosslinking agent; The self-sealing tire sealant according to any one of claims 1 to 8, characterized in that it comprises

10. e) 0.5% to 8% by weight, preferably 0.5% to 6% by weight, of at least one crosslinking initiator, preferably selected from the group consisting of lead oxides, other metal oxides, and peroxides, with peroxides being particularly preferred.

10. The self-sealing tire sealant according to claim 1, comprising:

11. f) 1.5% to 10% by weight of at least one adhesive, preferably a phenolic resin, a further fragrance resin, preferably an alpha-methylstyrene resin, and / or a chroman-indene resin, a fatty acid resin, preferably C ５ Adhesives which are hydrocarbon resins selected from the group consisting of resins and rubber resins, in particular rosin and / or balsam resins The self-sealing tire sealant according to any one of claims 1 to 10, characterized in that it comprises

12. At least the following components: a1) 12% to 22% by weight of at least one rubber, preferably a butyl rubber, the butyl rubber preferably having an isoprene content of 0.5 to 2.5 mol %; b1) 58% to 78% by weight of at least one polyolefin; c1) 4% to 8% by weight of at least one filler; d1) 0.5% to 2.5% by weight of said dispersion of at least one plasticizer and said at least one crosslinking agent, said dispersion being 50% to 80% by weight of crosslinking agent and 20% to 50% by weight of plasticizer; e1) 1.5% to 3.5% by weight of at least one crosslinking initiator; f1) 1.5% to 4.5% by weight of at least one adhesive; The self-sealing tire sealant according to any one of claims 1 to 11, characterized in that it comprises

13. At least the following components: a2) 13.5% to 29.5% by weight, preferably 20.5% to 29.5% by weight, of at least one rubber, preferably a butyl rubber, the butyl rubber preferably having an isoprene content of 0.5 to 2.5 mol %; b2) 47% to 77% by weight of at least one polyolefin; c2) 2.5% to 7.5% by weight of at least one filler; d2) 1% to 4% by weight of said dispersion of at least one plasticizer and said at least one crosslinking agent, said dispersion comprising 50% to 80% by weight of crosslinking agent and 20% to 50% by weight of plasticizer; e2) 2% to 4% by weight of at least one crosslinking initiator; f2) 1.5% to 4.5% by weight of at least one adhesive; The self-sealing tire sealant according to any one of claims 1 to 11, characterized in that it comprises

14. At least the following components: a3) 15.5% to 35.5% by weight of at least one rubber, preferably a butyl rubber, the butyl rubber preferably having an isoprene content of 0.5 to 5 mol %; b3) 40% to 70% by weight of at least one polyolefin; c3) 2.5% to 7.5% by weight of at least one filler; d3) 2% to 5% by weight of said dispersion of at least one plasticizer and said at least one crosslinking agent, said dispersion comprising 50% to 80% by weight of crosslinking agent and 20% to 50% by weight of plasticizer; e3) 2.5% to 5.5% by weight of at least one crosslinking initiator; f3) 1.5% to 5.5% by weight of at least one adhesive; The self-sealing tire sealant according to any one of claims 1 to 11, characterized in that it comprises

15. At least the following components: a4) 26% to 50% by weight of at least one rubber, preferably a butyl rubber, the butyl rubber preferably having an isoprene content of 0.5 to less than 5 mol%; b4) 14.5% to 54.5% by weight of at least one polyolefin; c4) 3% to 9% by weight of at least one filler; d4) 3% to 7% by weight of said dispersion of at least one plasticizer and said at least one crosslinking agent, said dispersion comprising 50% to 80% by weight of crosslinking agent and 20% to 50% by weight of plasticizer; e4) 4% to 8% by weight of at least one crosslinking initiator; f4) 2% to 7% by weight of at least one adhesive; The self-sealing tire sealant according to any one of claims 1 to 11, characterized in that it comprises

16. In a process for producing a self-sealing tire sealant comprising at least one crosslinking agent, in particular a tire sealant according to any one of claims 1 to 15, at least the following process steps are carried out: X1) producing or providing a dispersion of at least one crosslinker in at least one plasticizer; X2) providing additional components, such as preferably at least one polyolefin and / or at least one rubber, in one or more process steps; X3) adding said dispersion from step X1) to said components of step X2); A process including.

17. A pneumatic vehicle tire comprising at least on its inner surface opposite the treads a tire sealant according to any one of claims 1 to 15 or produced by the process according to claim 16.

18. 1. Use of a dispersion of at least one crosslinking agent, preferably p-benzoquinone dioxime, in at least one plasticizer, preferably selected from the group consisting of paraffin oil, MES (Mild Extraction Solvate), with paraffinic MES being particularly preferred, and vegetable oil, with rapeseed oil being particularly preferred, in the manufacture of a self-sealing tire sealant.

Images