Self-sealing tyre sealant, method for producing same, pneumatic vehicle tyre having the tyre sealant, and use of a dispersion of a cross-linking agent in a plasticiser in the production of a tyre sealant

Abstract

The invention relates to a self-sealing tyre sealant, to a method for producing same, and to a pneumatic vehicle tyre having the tyre sealant. The invention also relates to the use of a dispersion of a cross-linking agent in a plasticiser in the production of a tyre sealant. The cross-linking agent is added to the tyre sealant during its production in a dispersion made of at least one plasticiser and the at least one cross-linking agent.

Description

[0001] Description

[0002] Self-sealing tire sealant, method for its production and pneumatic vehicle tire comprising the tire sealant and use of a dispersion of a crosslinker in a plasticizer in the production of a tire sealant

[0003] The invention relates to a self-sealing tire sealant, a method for its production and a pneumatic vehicle tire comprising the tire sealant.

[0004] Furthermore, the invention relates to the use of a dispersion of a crosslinker in a plasticizer in the production of a tire sealant.

[0005] Self-sealing pneumatic vehicle tires are known, for example, from DE 10 2006 059 286 A1 by the applicant. Here, standard tire designs are subsequently provided with a layer of sealant. The self-sealing sealant is a self-adhesive, viscous sealing compound that is applied as a layer from the radially inside, in the projection area of ​​the belt package, to the radially innermost tire layer, the largely airtight inner layer. The sealant layer is capable of independently sealing punctures up to five millimeters in diameter. After a puncture through the tread and through the inner layer, the sealant completely encloses the penetrated foreign body, sealing the interior from the environment and thus preventing a loss of air pressure in the tire. The driver of the vehicle is not forced to immediately replace the defective tire with a full-size spare tire or an emergency tire.

[0006] The sealant is characterized by high airtightness, strong adhesiveness and balanced flow behavior.

[0007] Other self-sealing tire sealants are disclosed, for example, in WO2020 / 169234 A1 and EP 3546202 B1. According to the disclosures in these documents, sealants can contain crosslinking chemicals, such as crosslinkers and crosslinking initiators. The challenge with such fine chemicals is to distribute them as effectively as possible among the other components of the tire sealant.

[0008] EP 3546202 B1 discloses adding peroxides as crosslinking initiators to a mixture of organic solvents during the production of the sealant.

[0009] However, organic solvents have the disadvantage that they are highly volatile and have health disadvantages, such as irritating the respiratory tract in particular.

[0010] Crosslinkers, particularly quinone dioxime compounds such as p-benzoquinone dioxime, are added in the prior art in the production of tire sealants, particularly in powder form, as disclosed, for example, in EP3009260 A1. However, such powdered materials can be explosive, which significantly complicates handling and thus the production of sealants.

[0011] Powdered crosslinkers, such as p-benzoquinone dioxime, can also only be distributed homogeneously with great effort, partly due to the usually comparatively small amount in relation to the total mass of sealant.

[0012] An inhomogeneous distribution of crosslinkers in tire sealants leads to inhomogeneous crosslinking and thus to undesirable properties, such as poor creep behavior and low elasticity, which negatively impacts processability and sealing effectiveness. In the worst case, this can lead to sealant leakage from the tire.

[0013] The invention is therefore based on the object of providing a self-sealing tire sealant containing at least one crosslinking agent, which exhibits improved creep behavior and greater elasticity. The tire sealant should thus be easier to process during its production and application in pneumatic vehicle tires, achieving an improved sealing effect. Furthermore, unwanted leakage of tire sealant from the tire should be prevented. The tire sealant should be as environmentally and health-friendly as possible and be produced with less effort.

[0014] In addition, the underlying object is to provide a pneumatic vehicle tire comprising a tire sealant in which the above challenges with regard to production and sealing effect are solved.

[0015] The object is achieved by the tire sealant according to the invention as claimed in claim 1, the method according to the invention for producing a tire sealant containing at least one crosslinker, and the use according to the invention of a dispersion of a crosslinker in a plasticizer in the production of a tire sealant containing at least one crosslinker. Furthermore, the object is achieved by the pneumatic vehicle tire according to the invention comprising the tire sealant according to the invention.

[0016] By adding the at least one crosslinker to the tire sealant during its production in a dispersion of at least one plasticizer and the at least one crosslinker, a significantly improved distribution and homogeneity of the crosslinker in the tire sealant is surprisingly achieved. The tire sealant according to the invention exhibits greater elasticity and better creep behavior. The tire sealant also exhibits an improved sealing effect, preventing, among other things, sealant from leaking out of the tire.

[0017] The pneumatic vehicle tire according to the invention is characterized in particular by increased longevity after a puncture.

[0018] The sealant according to the invention and the tire according to the invention are manufactured to be as environmentally and health-friendly as possible.

[0019] For the sake of simplicity, the terms "self-sealing tire sealant" and "sealant" are used synonymously in the present invention unless otherwise stated. Furthermore, for the sake of simplicity, the terms "pneumatic vehicle tire" and "tire" are used synonymously in the present invention unless otherwise stated.

[0020] The components of the sealant according to the invention are explained in more detail below. All information, including the features of all preferred levels and embodiments of the sealant, also apply to the process according to the invention for producing the sealant and to the pneumatic vehicle tire according to the invention, including with regard to the combination of the features of all preferred levels and embodiments of the sealant with features of all

[0021] Preferred levels and embodiments of the process and the tire, unless expressly stated otherwise. Furthermore, all information, including the features of all preferred levels and embodiments, also applies to the use according to the invention.

[0022] All these resulting combinations of features are encompassed by the present invention.

[0023] Furthermore, the invention encompasses all combinations of different features of the same or different preference levels and embodiments of the sealing means with one another.

[0024] The weight percentages of the sealant components are based on the total amount of sealant, unless otherwise stated. The weight percentages of the dispersion components, particularly crosslinkers and plasticizers, are based on the total amount of the dispersion.

[0025] According to the invention, the at least one crosslinker is added to the tire sealant during its production in a dispersion of at least one plasticizer and the at least one crosslinker.

[0026] The tire sealant, the crosslinker, and the plasticizer can, in principle, be any type suitable for pneumatic vehicle tires known to those skilled in the art. The plasticizer can be any plasticizer known to those skilled in the art, in particular oils, such as, in particular, vegetable oils, such as, in particular, rapeseed oil, aromatic, naphthenic, or paraffinic mineral oil plasticizers, such as MES (mild extracted solvate) or paraffin oil (white oil) or RAE (residual aromatic extract) or TDAE (treated distillate aromatic extract), or rubber-to-liquid oils (RTL) or biomass-to-liquid oils (BTL), preferably with a polycyclic aromatics content of less than 3% by weight according to method IP 346. Mineral oils are particularly preferred as plasticizers.

[0027] Preferably, the plasticizer of the dispersion is an oil which is preferably selected from the group consisting of paraffin oil, MES (mild extracted solvate), with paraffinic MES being particularly preferred, and vegetable oils, with rapeseed oil being particularly preferred.

[0028] Using an oil as a plasticizer results in particularly good distribution of the crosslinker in the plasticizer and thus of the dispersion in the tire sealant. At the same time, oils, especially those selected from the group consisting of paraffin oil, MES (mildly extracted solvate), with paraffinic MES being particularly preferred, and vegetable oils, with rapeseed oil being particularly preferred, are particularly compatible with tire sealants characterized by excellent properties with regard to sealing effectiveness, flow behavior, and tackiness.

[0029] Furthermore, oils, in particular those selected from the group consisting of paraffin oil, MES (mild extracted solvate), with paraffinic MES being particularly preferred, and vegetable oils, with rapeseed oil being particularly preferred, are comparatively environmentally and health-friendly and do not tend to evaporate prematurely like organic solvents.

[0030] According to particularly advantageous embodiments, the oil is a paraffinic mineral oil, in particular paraffin oil. The crosslinker is preferably 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.

[0031] This results in particularly good cross-linking of the sealant and thus excellent properties in terms of sealing effect and flow behavior.

[0032] Preferably, the dispersion contains

[0033] 50 to 80 wt.% of crosslinkers, and

[0034] 20 to 50 wt.% plasticizers.

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

[0036] According to advantageous embodiments, the dispersion contains no further components, ie 0 wt.% further components.

[0037] The data in wt.% are based on the total amount of dispersion.

[0038] The dispersion particularly preferably contains

[0039] 60 to 70 wt.%, for example 65 wt.%, of crosslinking agents, and

[0040] 30 to 40 wt.%, for example 35 wt.%, of plasticizers and optionally up to 5 wt.% of other components, such as chalk.

[0041] According to advantageous embodiments, the dispersion contains no further components, ie 0 wt.% further components.

[0042] The data in wt.% are based on the total amount of dispersion.

[0043] According to preferred embodiments, the dispersion contains

[0044] 60 to 70 wt.%, for example 65 wt.%, p-benzoquinone dioxime (QDO), and 30 to 40 wt.%, for example 35 wt.%, oil, preferably paraffinic mineral oil, in particular paraffin oil.

[0045] According to advantageous embodiments, the dispersion contains no other constituents, i.e., 0 wt.% of other constituents. The wt.% values ​​are based on the total amount of dispersion.

[0046] The stated amounts of the components of the dispersion are to be understood and selected in such a way that they amount to 100% by weight.

[0047] With the preferred and particularly preferred amounts of crosslinkers and plasticizers, the object underlying the invention is achieved particularly well.

[0048] In particular, a homogeneous distribution of the crosslinker in the sealant results, whereby the sealant is characterized by high elasticity due to a higher and more homogeneous degree of crosslinking.

[0049] The self-sealing tire sealant d) preferably contains 0.5 to 7% by weight, particularly preferably 1.5 to 5% by weight, of the dispersion of at least one plasticizer and the at least one crosslinker, the data in % by weight relating here to the total amount of tire sealant.

[0050] Preferably, the self-sealing tire sealant is based on the crosslinking of at least one polyolefin and / or rubber with the at least one crosslinker.

[0051] This ensures particularly high compatibility of the sealant with the pneumatic vehicle tire, especially its inner layer. At the same time, such a sealant can be particularly well adapted to the various requirements of different tire types, resulting in excellent properties in terms of sealing effect, flow behavior, and tackiness.

[0052] According to advantageous embodiments, the sealing agent contains at least one rubber.

[0053] The rubber can be any type of rubber known to the person skilled in the art. A mixture of different rubbers is also conceivable. According to 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 (HR) and / or bromobutyl rubber (BI IR) and / or chlorobutyl rubber (CI IR) and / or silicone rubber.

[0054] These rubber types are particularly well suited to the processing temperatures during the production of the sealant and later during application, especially in pneumatic vehicle tires.

[0055] The self-sealing tire sealant particularly preferably contains at least one butyl rubber (HR). Butyl rubber, as known to those skilled in the art, is a copolymer of isobutene and isoprene.

[0056] The butyl rubber contained in the sealant preferably has an isoprene content of 0.5 to 5 mol%. Those skilled in the art know 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 potential of the rubber and thus of the polymer matrix in the sealant due to the increased unsaturation.

[0057] According to preferred embodiments, the sealant contains a butyl rubber with an isoprene content of 2.3 to 5.0 mol%.

[0058] This comparatively high isoprene content results in greater cross-linking and improved airtightness.

[0059] At the same time, this requires an increased amount of crosslinker and possibly crosslinking initiator, particularly in the case of an inhomogeneous distribution of crosslinking chemicals, or an inhomogeneous distribution of crosslinker with an increased isoprene content in the butyl rubber becomes more noticeable.

[0060] With the dispersion of crosslinker and plasticizer and the resulting more homogeneous distribution of crosslinker in the sealant, the invention also enables the use of a butyl rubber with an isoprene content of 2.3 to 5.0 mol% and the associated advantages. The invention thus also enables the full exploitation of the crosslinking potential offered by the presence of a butyl rubber with an isoprene content of 2.3 to 5.0 mol%.

[0061] Due to the more homogeneous distribution of the dispersion, it may not be necessary to use an increased amount of crosslinker or the amount of crosslinker can be precisely matched to the isoprene content, so that neither crosslinker nor unsaturated sites of the polymer chains are wasted.

[0062] The self-sealing tire sealant preferably contains a) 9 to 50 wt.%, particularly preferably 12 to 50 wt.%, of at least one rubber, wherein the rubber is preferably butyl rubber (HR).

[0063] According to particularly advantageous embodiments, the sealant a) contains 20.5 to 40 wt.%, particularly preferably 20.5 to 29.5 wt.%, of at least one butyl rubber.

[0064] As a result, the sealant exhibits a particularly good property profile, including sealing effectiveness, flow behavior, and tackiness, and in particular, very good airtightness. At the same time, these comparatively high amounts of butyl rubber in the sealant have the advantage that increased crosslinking and improved airtightness can be achieved when using a butyl rubber with an isoprene content of 2.3 to 5.0 mol%.

[0065] According to advantageous embodiments, the sealant contains at least one polyolefin.

[0066] This achieves optimal flow behavior while at the same time ensuring good manufacturability (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, again preferably 1200 to 1600 g / mol, again particularly preferably 1200 to 1400 g / mol, for example 1300 g / mol. A polyolefin with the stated Mn ranges is particularly suitable for producing the desired flowability while simultaneously providing a sealing effect of the sealant in the event of a puncture.

[0068] “Polyolefins” are understood to mean, in particular, those polyalkenes which are obtained by polymerisation of, in particular, unbranched alkenes, such as polyethylenes, polypropylenes, polybutenes and polyisobutenes.

[0069] It is particularly preferred that the at least one polyolefin is at least one polybutene.

[0070] This adjusts the stickiness of the finished sealant and determines the flowability in the production process as well as the local strength of the finished sealant.

[0071] It can also be a mixture of two or more polybutenes, each with a Mn of 400 to 2500 g / mol, whereby the polybutenes can differ in Mn.

[0072] Suitable polybutenes, also called polybutylene, are available, for example, under the trade name Indopol® Polybutene from INEOS Capital Limited. A blend of at least one polybutene with at least one other polyolefin is also conceivable.

[0073] Preferably, the self-sealing tire sealant b) contains 11 to 80 wt.% of at least one polyolefin, wherein the polyolefin is preferably polybutene.

[0074] According to particularly advantageous embodiments, the sealant b) contains 14.5 to 65 wt.% of at least one polyolefin.

[0075] The sealant may also contain other components, such as crosslinking initiators, filler(s), tackifiers, other plasticizers, such as.

[0076] B. oil(s), and optionally other additives, such as B. color pigments and / or zinc oxide and / or sulfur.

[0077] According to preferred embodiments of the invention, the sealant contains at least one filler, in particular at least one active filler. The filler is preferably selected from carbon black and silicon dioxide.

[0078] The silicon dioxide is preferably amorphous silicon dioxide, for example, precipitated silica, also known as precipitated silicon dioxide. Alternatively, pyrogenic silicon dioxide, for example, can also be used.

[0079] The filler carbon black is particularly preferred.

[0080] Suitable carbon blacks include all types of carbon black known to those skilled in the art. The carbon black is preferably selected from industrial carbon blacks and pyrolysis carbon blacks, with industrial carbon blacks being even more preferred.

[0081] This has the advantage of increasing the sealant's cohesion and reducing its stickiness during the manufacturing process. At the same time, the sealant's in-place strength and tear properties are improved.

[0082] According to advantageous embodiments of the invention, a carbon black is used which has an iodine adsorption number according to ASTM D 1510 of 20 to 180 g / kg, particularly preferably 30 to 140 g / kg, and a DBP number according to ASTM D 2414 of 30 to 200 m 1 / 100 g, preferably 90 to 180 m 1 / 100 g, particularly preferably 110 to 180 ml / 100 g.

[0083] According to further preferred embodiments of the invention, a carbon black of type N326 is used.

[0084] A mixture of two or more carbon blacks is also conceivable.

[0085] Preferably, the self-sealing tire sealant c) contains 2 to 15 wt.% of at least one filler, wherein the filler is preferably selected from carbon black and silicon dioxide, wherein carbon black is particularly preferred.

[0086] With the quantities mentioned, the sealant has particularly good local stability due to the optimized creep behavior, a very good sealing effect and very good tear properties.

[0087] According to preferred embodiments of the invention, the sealant contains at least one crosslinking initiator. A crosslinking initiator is a chemical compound that initiates the crosslinking of the sealant.

[0088] The at least one crosslinking initiator is preferably selected from the group consisting of lead oxide, other metal oxides and peroxides, with peroxides being particularly preferred.

[0089] The peroxide(s) are preferably selected from the group consisting of diaroyl peroxides, diacyl peroxides and peroxy esters.

[0090] The crosslinking initiator can be added as a pure substance or in a mixture with, for example, a stabilizer such as dibutyl maleate.

[0091] For example, a mixture of 50 wt.% dibenzoyl peroxide and 50 wt.% dibutyl maleate as a stabilizer is conceivable.

[0092] Furthermore, it is conceivable that the crosslinking initiator is added in a liquid, as described in EP 3546202 B1, for example with a weight proportion of 35 to 40 wt.%.

[0093] For all mixtures, only the amount of peroxide contained is included in the specification of the amount of crosslinking initiator in the sealant, ie, for example, that in the stated amounts of at least one crosslinking initiator

[0094] Accompanying substances such as dibutyl maleate or the liquid are not included.

[0095] The self-sealing tire sealant e) preferably contains 0.5 to 8 wt.%, preferably 0.5 to 6 wt.%, of at least one crosslinking initiator.

[0096] In particular, the combination of a crosslinker with a crosslinking initiator in the specified quantities results in a particularly effective tire sealant that seals quickly in the event of a puncture and can be further optimized for tires with different internal pressures.

[0097] According to advantageous embodiments, the sealant contains at least one tackifier, particularly in the case where the sealant does not already exhibit sufficient tackiness due to the components it contains, in particular the polymers. "Tackifier" is understood to mean, in principle, any substance that increases the tackiness of the sealant.

[0098] According to advantageous embodiments of the invention, the tackifier is at least one hydrocarbon resin.

[0099] It is clear to the person skilled in the art that hydrocarbon resins are polymers composed of monomers, whereby the hydrocarbon resin is formally composed of derivatives of the monomers by linking the monomers to one another.

[0100] In the context of the present application, the term "hydrocarbon resins" encompasses resins that contain carbon atoms and hydrogen atoms and optionally heteroatoms, such as, in particular, oxygen atoms. The hydrocarbon resin is preferably selected from the group consisting of phenolic resins, other aromatic resins, preferably alpha-methylstyrene-styrene resins and / or indene-coumarone resins, aliphatic resins, preferably Cs resins, and gum resins, in particular rosin and / or balsam resins. The tackifier is particularly preferably an aliphatic Cs resin.

[0101] Preferably, the self-sealing tire sealant f) contains 1.5 to 10 wt.% of at least one tackifier.

[0102] With such quantities, the stickiness and viscosity of the sealant are further optimized.

[0103] The self-sealing tire sealant preferably also contains g) up to 1.1% by weight of zinc oxide, in particular 0.1 to 1.1% by weight.

[0104] Zinc oxide improves the stability of cross-linking points in terms of longevity and resistance to heat.

[0105] According to advantageous embodiments, the self-sealing

[0106] Tire sealant also contains at least one further plasticizer, in particular to further optimize the sealant with regard to processability depending on the composition of its other components.

[0107] The further plasticizer can be any plasticizer known to the person skilled in the art, in particular oils, such as in particular aromatic, naphthenic or paraffinic mineral oil plasticizers, such as MES (mild extracted solvate) or RAE (residual aromatic extract) or TDAE (treated distillate aromatic extract), or rubber-to-liquid oils (RTL) or biomass-to-liquid oils (BTL), preferably with a polycyclic aromatics content of less than 3% by weight according to method IP 346. Mineral oils are particularly preferred as plasticizers.

[0108] When using mineral oil, it is preferably selected from the group consisting of DAE (Distilled Aromatic Extracts), RAE (Residual Aromatic Extract), TDAE (Treated Distilled Aromatic Extracts), MES (mild extracted solvate) and naphthenic oils.

[0109] MES (mild extracted solvate) is particularly preferred as an additional plasticizer, with paraffinic MES (mild extracted solvate) also being particularly preferred here.

[0110] According to preferred embodiments, the self-sealing tire sealant h) contains 0.5 to 8 wt.% oil as a further plasticizer.

[0111] According to further preferred embodiments, the self-sealing tire sealant contains no further plasticizer besides the plasticizer already contained in the dispersion, i.e. h) 0 wt.% further plasticizer.

[0112] By adding the dispersion of crosslinker in plasticizer according to the invention, the addition of further plasticizer can thus be dispensed with at the same time, according to advantageous embodiments.

[0113] This eliminates the need to weigh and add an additional component. The self-sealing tire sealant preferably also contains up to 1% by weight, in particular 0.1 to 1.0% by weight, of sulfur.

[0114] This increases the high-temperature stability of cross-linking points.

[0115] According to preferred embodiments, the sealant thus contains the following components: butyl rubber, polyolefin, filler, dispersion of crosslinker and plasticizer, crosslinking initiator, tackifier, filler and optionally further plasticizer, zinc oxide and sulfur.

[0116] All versions and preferred features of all preference levels apply to the type and quantity of components.

[0117] According to particularly preferred embodiments, the sealant contains the components in the specified amounts a) to i) in combination with one another. All embodiments and preferred features of all preference levels apply to the type and quantity of the components.

[0118] According to a particularly advantageous embodiment of the invention, the self-sealing tire sealant contains at least the following components: a1) 12 to 22% by weight of at least one rubber, wherein the rubber is preferably butyl rubber, wherein the butyl rubber preferably has an isoprene content of 0.5 to 2.3 mol%; and b1) 58 to 78% by weight of at least one polyolefin, and c1) 4 to 8% by weight of at least one filler; and d1) 0.5 to 2.5% by weight of the dispersion of at least one plasticizer and the at least one crosslinker, and wherein the dispersion contains 50 to 80% by weight of crosslinkers and 20 to 50% by weight of plasticizers; and e1) 1.5 to 3.5 wt.% of at least one crosslinking initiator, and f1) 1.5 to 4.5 wt.% of at least one tackifier.

[0119] This sealant preferably also contains g1) 0.3 to 1.1 wt.% zinc oxide; and h1) 0.5 to 2.5 wt.% oil; and optionally i1) up to 0.6 wt.% sulfur, in particular 0.1 to 0.6 wt.% sulfur.

[0120] Such a sealant with the composition a1) to i1) is particularly suitable for car tires.

[0121] One aspect of the invention is a passenger car tire which has the sealant with the composition a1) to i1) at least on the inner surface opposite the tread.

[0122] For components a1) to i1), the above-mentioned characteristics regarding type and, where applicable, quantity, including all embodiments and degrees of preference, also apply. For example, in the case of component "b1) 58 to 78 wt.% of at least one polyolefin," the polyolefin is preferably polybutene.

[0123] According to a further particularly advantageous embodiment of the invention, the self-sealing tire sealant contains 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, wherein the rubber is preferably butyl rubber, wherein the butyl rubber preferably has an isoprene content of 0.5 to 2.3 mol%; and b2) 47 to 77% by weight of at least one polyolefin, and c2) 2.5 to 7.5% by weight of at least one filler, and d2) 1 to 4% by weight of the dispersion of at least one plasticizer and the at least one crosslinker, and wherein the dispersion contains 50 to 80% by weight of crosslinkers and 20 to 50% by weight of plasticizers; and e2) 2 to 4 wt.% of at least one crosslinking initiator, and f2) 1.5 to 4.5 wt.% of at least one tackifier.

[0124] Preferably, this sealant also optionally contains g2) up to 1.0 wt.% zinc oxide, in particular 0.1 to 1.0 wt.% zinc oxide; and optionally h2) up to 4 wt.% oil, in particular 0.5 to 4 wt.% oil; and optionally i2) up to 1.0 wt.% sulfur, in particular 0.1 to 1.0 wt.% sulfur.

[0125] Such a sealant with the composition a2) to i2) is particularly suitable for van tires.

[0126] One aspect of the invention is a van tire comprising the sealant having the composition a2) to i2) at least on the inner surface opposite the tread.

[0127] For components a2) to i2), the above-mentioned characteristics regarding type and, if applicable, quantity, including all embodiments and preference levels, also apply.

[0128] According to a further particularly advantageous embodiment of the invention, the self-sealing tire sealant contains at least the following components: a3) 15.5 to 35.5% by weight of at least one rubber, wherein the rubber is preferably butyl rubber, wherein the butyl rubber preferably has an isoprene content of 0.5 to 5 mol%; and b3) 40 to 70% by weight of at least one polyolefin, and c3) 2.5 to 7.5% by weight of at least one filler, and d3) 2 to 5% by weight of the dispersion of at least one plasticizer and the at least one crosslinker, and wherein the dispersion contains 50 to 80% by weight of crosslinkers and 20 to 50% by weight of plasticizers; and e3) 2.5 to 5.5% by weight of at least one crosslinking initiator, and f3) 1.5 to 5.5% by weight of at least one tackifier.

[0129] Preferably, this sealant also optionally contains g3) up to 1.0 wt.% zinc oxide, in particular 0.1 to 1.0 wt.% zinc oxide; and optionally h3) up to 5 wt.% oil, in particular 0.5 to 5 wt.% oil; and optionally i3) up to 1.0 wt.% sulfur, in particular 0.1 to 1.0 wt.% sulfur.

[0130] Such a sealant with the composition a3) to i3) is particularly suitable for truck tires.

[0131] One aspect of the invention is a truck tire comprising the sealant having the composition a3) to i3) at least on the inner surface opposite the tread.

[0132] For components a3) to i3), the above-mentioned characteristics regarding type and, if applicable, quantity, including all embodiments and preference levels, also apply.

[0133] According to a further particularly advantageous embodiment of the invention, the self-sealing tire sealant contains at least the following components: a4) 26 to 50% by weight of at least one rubber, wherein the rubber is preferably butyl rubber, wherein the butyl rubber preferably has an isoprene content of 0.5 to 5 mol%; and b4) 14.5 to 54.5% by weight of at least one polyolefin, and c4) 3 to 9% by weight of at least one filler, and d4) 3 to 7% by weight of the dispersion of at least one plasticizer and the at least one crosslinker, and wherein the dispersion contains 50 to 80% by weight of crosslinkers and 20 to 50% by weight of plasticizers; and e4) 4 to 8% by weight of at least one crosslinking initiator, and f4) 2 to 7% by weight of at least one tackifier.

[0134] Preferably, this sealant optionally also contains g4) up to 1.0 wt.% zinc oxide, in particular 0.1 to 1.0 wt.% zinc oxide; and h4) 2 to 8 wt.% oil; and optionally i4) up to 1.0 wt.% sulfur, in particular 0.1 to 1.0 wt.% sulfur.

[0135] Such a sealant with the composition a4) to i4) is particularly suitable for agricultural tires or construction site tires, such as a tire for agricultural tractors, self-propelled harvesters, trailers, wheel loaders or excavators.

[0136] One aspect of the invention is an agricultural tire or construction tire which has the sealant with the composition a4) to i4) at least on the inner surface opposite the tread.

[0137] For components a4) to i4), the above-mentioned characteristics regarding type and, where applicable, quantity, including all embodiments and preference levels, also apply.

[0138] In this case, as already explained several times, all further statements on these features also apply to the combinations a1) to i1), a2) to i2), a3) to i3) and a4) to i4).

[0139] Thus, in all the above-mentioned embodiments, the polyolefin is preferably a polybutene, the filler is carbon black, the tackifier is a hydrocarbon resin, the crosslinking initiator is a peroxide, etc.

[0140] In particular, in all the above-mentioned embodiments, the plasticizer is preferably an oil, which is particularly preferably selected from the group consisting of paraffin oil, MES (mild extracted solvate), with paraffinic MES being particularly preferred, and vegetable oils, with rapeseed oil being particularly preferred.

[0141] According to particularly advantageous embodiments, the oil is a paraffinic mineral oil, in particular paraffin oil.

[0142] In particular, in all the above-mentioned embodiments, the crosslinker 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. The process according to the invention for producing a self-sealing tire sealant containing at least one crosslinker comprises at least the following process steps:

[0143] X1 ) Producing or providing a dispersion of at least one crosslinker in at least one plasticizer;

[0144] X2) Providing further components, such as preferably at least one polyolefin and / or at least one rubber in one or more process steps;

[0145] X3) Addition of the dispersion from step X1) to the components from step X2).

[0146] The dispersion in step X1) can be purchased commercially, such as a dispersion of 60 to 65 wt% p-benzoquinone dioxime and 35 to 40 wt% oil, which may optionally contain up to 5 wt% chalk and is available under the trade name QDO 65MK from LORD Germany Feinchemie GmbH.

[0147] If the dispersion in step X1 ) is not commercially available, it can be prepared as follows:

[0148] X01 ) Providing at least one crosslinker, wherein the crosslinker is preferably selected from the group consisting of quinonedioxime compounds, quinones, divinylbenzene and 1,4-dinitrosobenzene, wherein quinonedioxime compounds and in particular p-benzoquinonedioxime (QDO) are particularly preferred; and

[0149] X02) Providing at least one plasticizer, wherein the plasticizer is preferably an oil, which is preferably selected from the group consisting of paraffin oil, MES (mild extracted solvate), with paraffinic MES being particularly preferred, and vegetable oils, with rapeseed oil being particularly preferred; and X03) Intensively dispersing the crosslinker from step X01) with the plasticizer from step X02), thereby obtaining a dispersion of at least one crosslinker in at least one plasticizer. According to 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 produce a masterbatch; and

[0150] X2-2) Mixing the masterbatch with at least one polyolefin to produce a component A; and

[0151] X2-3) Mixing at least one crosslinking initiator with at least one polyolefin, thereby containing a component B; and

[0152] X2-4) Mixing component A and component B to produce the tire sealant.

[0153] The addition of the dispersion according to step X3) preferably takes place during step X2-1).

[0154] The mixing of the components according to all steps takes place in devices known to those skilled in the art.

[0155] The mixing in step X2-2) is preferably carried out in an extruder, preferably a twin-screw extruder.

[0156] The mixing in step X2-3) preferably takes place in a mixing tank.

[0157] The mixing in step X2 -4) is preferably carried out in a static mixer.

[0158] A further subject of the present invention, as already stated, is a pneumatic vehicle tire which has the tire sealant according to the invention, including all the aforementioned embodiments, at least on the inner surface opposite the tread.

[0159] As already stated, the present invention further relates to the use of a dispersion of at least one crosslinker, preferably p-benzoquinone dioxime, in at least one plasticizer, which is preferably selected from the group consisting of paraffin oil, MES (mild extracted solvate), with paraffinic MES being particularly preferred, and vegetable oils, with rapeseed oil being particularly preferred, in the production of a self-sealing tire sealant. The invention will be explained in more detail below using exemplary embodiments.

[0160] Table 1 shows the hysteresis behavior by the mean tangent delta value at 100 °C as well as the creep behavior for a sealant E1 according to the invention and a comparison sealant V1.

[0161] The amounts of the components are given in wt. %. E1 was prepared using the process described above in steps X1) to X3) including X2-1) to X2-4), with the dispersion being added in step X2-1). V1 was prepared according to steps X2-1) to X-2-4), with the crosslinker being added in step X2-1).

[0162] The properties were determined using the following methods:

[0163] • Average tangent delta from frequency sweep at 100 °C

[0164] • Vertical creep: measured creep length: the length in millimeters (mm) of a creep sample after vertical creep at 125 °C

[0165] The values ​​for tangent delta and creep length were determined by averaging two samples each.

[0166] Table 1 1 ) Butyl rubber: Isoprene content 1.85 mol-%

[0167] 2) Butyl rubber: Isoprene content 2.3 mol%

[0168] 3) p-Benzoquinone dioxime: powder

[0169] 4) p-Benzoquinone dioxime: Dispersion: QDO 65MK, LORD Germany Feinchemie GmbH

[0170] 5) Peroxide: Mixture of 50 wt% dibenzoyl peroxide and 50 wt% dibutyl maleate

[0171] 6) Other ingredients:

[0172] For V1 and E1: 3 wt% aliphatic Cs resin, 0.7 wt% zinc oxide, 1.0 wt% paraffinic MES oil, 0.3 wt% sulfur;

[0173] For E2: 3 wt% aliphatic Cs resin, 0.5 wt% zinc oxide, 2.0 wt% paraffinic MES oil, 0.5 wt% sulfur.

[0174] As can be seen in Table 1, the sealant according to the invention achieves a lower tangent delta at 100 °C. This indicates better and more homogeneous crosslinking.

[0175] At the same time, E1 shows improved and reduced creep behavior.

[0176] This improves the sealant's processability during production and during application in pneumatic vehicle tires. At the same time, unwanted leakage of sealant from the tire is prevented, or at least the risk of this happening is significantly reduced.

Claims

Patent claims 1. Self-sealing tire sealant containing at least one crosslinker, characterized in that the at least one crosslinker is added to the tire sealant during its manufacture in a dispersion of at least one plasticizer and the at least one crosslinker.

2. Self-sealing tire sealant according to claim 1, characterized in that the plasticizer is an oil which is preferably selected from the group consisting of paraffin oil, MES (mild extracted solvate), wherein paraffinic MES is particularly preferred, and vegetable oils, wherein rapeseed oil is particularly preferred.

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

4. Self-sealing tire sealant according to one of the preceding claims, characterized in that the dispersion contains 50 to 80 wt.%, preferably 60 to 70 wt.%, crosslinkers and 20 to 50 wt.%, preferably 30 to 40 wt.%, plasticizers, wherein the values ​​in wt.% are based on the total amount of dispersion.

5. Self-sealing tire sealant according to one of the preceding claims, characterized in that it is based on the crosslinking of at least one polyolefin and / or rubber with the at least one crosslinking agent.

6. Self-sealing tire sealant according to one of the preceding claims, characterized in that it a) Contains 9 to 50 wt.%, preferably 12 to 50 wt.%, particularly preferably 20.5 to 40 wt.%, at least one rubber, wherein the rubber is preferably butyl rubber (HR), wherein the butyl rubber preferably has an isoprene content of 0.5 to 5 mol%.

7. Self-sealing tire sealant according to one of the preceding claims, characterized in that it contains b) 11 to 80 wt.%, preferably 14.5 to 65 wt.%, at least one polyolefin, wherein the polyolefin is preferably polybutene.

8. Self-sealing tire sealant according to one of the preceding claims, characterized in that it contains c) 2 to 15 wt.% of at least one filler, wherein the filler is preferably selected from carbon black and silicon dioxide, wherein carbon black is particularly preferred.

9. Self-sealing tire sealant according to one of the preceding claims, characterized in that it contains d) 0.5 to 7 wt.%, preferably 1.5 to 5 wt.%, of the dispersion of at least one plasticizer and the at least one crosslinking agent.

10. Self-sealing tire sealant according to one of the preceding claims, characterized in that it contains e) 0.5 to 8 wt.%, preferably 0.5 to 6 wt.%, at least one crosslinking initiator, wherein the crosslinking initiator is preferably selected from the group consisting of lead oxide, other metal oxides and peroxides, wherein peroxides are particularly preferred.

11. Self-sealing tire sealant according to one of the preceding claims, characterized in that it contains f) 1.5 to 10 wt.% of at least one tackifier, wherein the tackifier is preferably a hydrocarbon resin, which is preferably selected from the group consisting of phenolic resins, further aromatic resins, preferably alpha-methylstyrene-styrene resins and / or indene-coumarone resins, aliphatic resins, preferably Cs resins, and gum resins, in particular rosin and / or balsam resins.

12. Self-sealing tire sealant according to one of the preceding claims, characterized in that it contains at least the following components: a1) 12 to 22 wt.% of at least one rubber, wherein the rubber is preferably butyl rubber, the butyl rubber preferably having an isoprene content of 0.5 to 2.5 mol%; and b1) 58 to 78 wt.% of at least one polyolefin, and c1) 4 to 8 wt.% of at least one filler; and d1) 0.5 to 2.5 wt.% of the dispersion of at least one plasticizer and the at least one crosslinking agent, wherein the dispersion contains 50 to 80 wt.% of crosslinking agents and 20 to 50 wt.% of plasticizers; and e1 ) 1.5 to 3.5 wt.% of at least one crosslinking initiator, and f1 ) 1.5 to 4.5 wt.% of at least one stickiness agent.

13. Self-sealing tire sealant according to any one of claims 1 to 11, characterized in that it contains at least the following components: a2) 13.5 to 29.5 wt.%, preferably 20.5 to 29.5 wt.%, of at least one rubber, wherein the rubber is preferably butyl rubber, wherein the butyl rubber preferably has an isoprene content of 0.5 to 2.5 mol%; and b2) 47 to 77 wt.% of at least one polyolefin, and c2) 2.5 to 7.5 wt.% of at least one filler, and d2) 1 to 4 wt.% of the dispersion of at least one plasticizer and the at least one crosslinker, wherein the dispersion contains 50 to 80 wt.% of crosslinkers and 20 to 50 wt.% of plasticizers; and e2) 2 to 4 wt.% of at least one crosslinking initiator, and f2) 1.5 to 4.5 wt.% of at least one stickiness agent.

14. Self-sealing tire sealant according to any one of claims 1 to 11, characterized in that it contains at least the following components: a3) 15.5 to 35.5 wt.% of at least one rubber, wherein the rubber is preferably butyl rubber, wherein the butyl rubber preferably has an isoprene content of 0.5 to 5 mol%; and b3) 40 to 70 wt.% of at least one polyolefin, and c3) 2.5 to 7.5 wt.% of at least one filler, and d3) 2 to 5 wt.% of the dispersion of at least one plasticizer and the at least one crosslinker, wherein the dispersion contains 50 to 80 wt.% of crosslinkers and 20 to 50 wt.% of plasticizers; and e3) 2.5 to 5.5 wt.% of at least one crosslinking initiator, and f3) 1.5 to 5.5 wt.% of at least one stickiness agent.

15. Self-sealing tire sealant according to any one of claims 1 to 11, characterized in that it contains at least the following components: a4) 26 to 50 wt.% of at least one rubber, wherein the rubber is preferably butyl rubber, wherein the butyl rubber preferably has an isoprene content of 0.5 to less than 5 mol%; and b4) 14.5 to 54.5 wt.% of at least one polyolefin, and c4) 3 to 9 wt.% of at least one filler, and d4) 3 to 7 wt.% of the dispersion of at least one plasticizer and the at least one crosslinking agent, wherein the dispersion contains 50 to 80 wt.% of crosslinking agents and 20 to 50 wt.% of plasticizers; and e4) 4 to 8 wt.% of at least one crosslinking initiator, and f4) 2 to 7 wt.% of at least one tackifier.

16. Method for producing a self-sealing tire sealant comprising at least one crosslinking agent, in particular the tire sealant according to any one of claims 1 to 15, wherein the method comprises at least the following process steps: X1) Manufacturing or providing a dispersion of at least one crosslinker in at least one plasticizer; X2) Providing further components, preferably at least one polyolefin and / or at least one rubber, in one or more process steps; X3) Addition of the dispersion from step X1) to the components from step X2).

17. A vehicle pneumatic tire comprising the tire sealant according to any one of claims 1 to 15 or the tire sealant produced according to the method of claim 16, at least on the inner surface opposite the tread.

18. 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 extracted solvent), wherein paraffinic MES is particularly preferred, and vegetable oils, wherein rapeseed oil is particularly preferred, in the production of a self-sealing tire sealant.

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