阅读说明：本技术 自动密封的轮胎密封剂及包含轮胎密封剂的车辆充气轮胎 (Self-sealing tire sealant and pneumatic vehicle tire comprising same ) 是由 米哈伊尔·多罗申科 雪莉-安·蒂姆·基 于 2019-12-16 设计创作，主要内容包括：本发明涉及一种自动密封的轮胎密封剂以及一种包含该轮胎密封剂的车辆充气轮胎。根据本发明的密封剂至少包含以下成分：-10至30重量％的至少一种聚烯烃,以及-35至60重量％的至少一种橡胶,以及-1.0至3.0重量％的至少一种交联剂,以及-1.8至5.0重量％的至少一种交联引发剂。根据本发明的车辆充气轮胎至少在与胎面相反的内表面上具有根据本发明的密封剂。(The present invention relates to a self-sealing tire sealant and a pneumatic tire for a vehicle including the same. The sealant according to the present invention contains at least the following components: -10 to 30 wt% of at least one polyolefin, and-35 to 60 wt% of at least one rubber, and-1.0 to 3.0 wt% of at least one crosslinking agent, and-1.8 to 5.0 wt% of at least one crosslinking initiator. The pneumatic vehicle tire according to the present invention has the sealant according to the present invention at least on the inner surface opposite to the tread.)

1. An automatic sealing tire sealant, characterized by comprising at least the following components:

10 to 30% by weight of at least one polyolefin, and

35 to 60% by weight of at least one rubber, and

1.0 to 3.0% by weight of at least one crosslinking agent, and

-1.8 to 5.0 wt% of at least one crosslinking initiator.

2. Tyre sealant according to claim 1, characterized in that it comprises 2.0 to 20 wt. -%, preferably 2.0 to 12 wt. -% of at least one filler.

3. The tire sealant according to claim 2, wherein the filler is selected from the group consisting of carbon black, silica and magnetic particles, wherein the carbon black includes industrial carbon black and pyrolytic carbon black.

4. A tire sealant according to any of the preceding claims, wherein the tire sealant comprises 2.0 to 20 wt% of at least one adhesive.

5. The tire sealant according to claim 4, wherein the adhesive comprises at least one hydrocarbon resin.

6. A tyre sealant according to one of the preceding claims, characterized in that it comprises 1.5 to 3.0 wt. -% of at least one cross-linking agent.

7. A tyre sealant according to one of the preceding claims, characterized in that it comprises 2.0 to 4.0 of at least one crosslinking initiator.

8. A pneumatic vehicle tire having the tire sealant according to one of claims 1 to 7 at least on an inner surface opposite to a tread.

Technical Field

The present invention relates to a self-sealing tire sealant and a pneumatic tire for a vehicle including the tire sealant.

Background

A self-sealing vehicle pneumatic tire is known, for example, from DE 102006059286 a1 of the applicant. Standard tire constructions are provided herein that subsequently have a sealant layer. The self-sealing sealant is a self-adhesive, tacky sealant which is applied as a layer from the radially inner part in the projected area of the cord band onto the radially innermost tire layer (the inner coating which is largely embodied gas-tightly). The sealant coating is capable of automatically sealing perforations up to five millimeters in diameter. After the tread has been pierced until the inner coating has been pierced, the sealant completely surrounds the intruding foreign bodies, seals the interior space from the surroundings and thus prevents the loss of compressed air from the tire. The vehicle operator does not have to immediately use up a good spare or emergency wheel to replace the defective tire.

The sealant is distinguished by gas tightness, strong adhesion and balanced flow behavior, wherein the performance characteristics are designed for use in PKW (passenger car) vehicle pneumatic tires having an internal pressure of 2 to 2.5 bar.

Disclosure of Invention

The invention is based on the object of providing, based on the prior art, a self-sealing tire sealant which is suitable for tires having a high internal pressure, in particular 3.5 bar and higher. For this reason, the sealant should have an optimum characteristic pattern formed by viscosity, flow behavior and elasticity, and adhesion.

This object is achieved in that the sealant comprises at least the following components:

10 to 30% by weight of at least one polyolefin, and

35 to 60% by weight of at least one rubber, and

1.0 to 3.0% by weight of at least one crosslinking agent, and

-1.8 to 5.0 wt% of at least one crosslinking initiator.

By combining the specified amounts of ingredients, the sealant has optimal flow behavior, optimal viscosity and elasticity, and optimal adhesion. On the basis of this performance characteristic, it is ensured that the sealant continues to seal when applied to a tire having an internal pressure of 3.5 bar and higher and, at the same time, does not flow out of the puncture site. Here, the viscosity of the sealant increases, especially because the amount of the crosslinking agent and the crosslinking initiator and the rubber increases and the amount of the polyolefin decreases compared to the prior art.

Thus, a self-sealing design of a tire with a high internal pressure is also possible by means of the invention.

The values given in% by weight relate accordingly to the total amount of sealant.

Within the scope of the present invention, the terms "sealant" and "tire sealant" are used synonymously and relate to self-sealing (self-sealing) sealant compositions, unless explicitly stated otherwise.

The tire sealant according to the present invention may be prepared by a method known in the art.

Another subject of the invention is a pneumatic vehicle tyre having, at least on the inner surface opposite to the tread, the tyre sealant according to the invention, including all the mentioned embodiments.

The pneumatic vehicle tire according to the present invention is particularly designed such that it operates at an internal pressure of 3.5 bar or more. The vehicle pneumatic tires can be all types of tires that operate with such internal pressure, such as, in particular, truck tires, LKW (heavy-duty vehicle) tires, industrial tires.

The composition of the sealant according to the present invention will be described in more detail below.

Detailed Description

According to the invention, the self-sealing tire sealant contains 10 to 30% by weight of at least one polyolefin. The amount of the at least one polyolefin is preferably from 15 to 30% by weight, for example 25% by weight. Optimum flow behavior (in particular optimum viscosity) is achieved with amounts of 10 to 30% by weight, preferably 15 to 30% by weight, while good producibility (processability) and adhesion of the sealant are achieved.

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

Polyolefins having the mentioned ranges for Mn are particularly suitable in order to produce the desired flowability in the event of a failure while achieving the sealing effect of the sealant.

It is particularly preferred here that the at least one polyolefin is at least one polybutene.

This sets the adhesiveness of the finished sealant, and determines the fluidity during production and the local position fixing property of the finished sealant.

The at least one polyolefin may also be a mixture of two or more polybutenes each having an Mn of 400g/mol to 2500g/mol, wherein the polybutenes may be different in Mn.

Suitable polybutenes (also referred to as polyisobutylenes) may be obtained, for example, under the trade name Ineos Capitate LimitedPolybutene. Mixtures of at least one polybutene with at least one additional polyolefin are also envisaged.

According to a particularly advantageous development of the invention, the at least one polyolefin has a chlorine content of less than or equal to 5mg/kg, preferably less than or equal to 3 mg/kg. The values relate to milligrams (mg) of chlorine per kilogram (kg) of polyolefin. In a preferred embodiment of the present invention, the self-sealing tire sealant comprises at least one polyolefin having a chlorine content of less than or equal to 1.5mg/kg, particularly preferably less than 1 mg/kg. Preferably, the polyolefin is polybutene.

Thus, according to a particularly preferred embodiment of the invention, the sealant comprises at least one polybutene having a chlorine content of less than or equal to 5mg/kg, preferably less than or equal to 3mg/kg, particularly preferably less than 1 mg/kg. Suitable polybutenes (also referred to as polyisobutylenes) are, for example, the trade name from BASF corporationThis is known as follows. In particular, hereV-500, V-640 or V-190 are suitable.

According to the present invention, the self-sealing tire sealant contains 35 to 60% by weight of at least one rubber. The amount of the at least one rubber is preferably from 40 to 60% by weight, particularly preferably from 50 to 55% by weight, for example 52% by weight, based on the total amount of sealant.

The rubber is here raw rubber, and therefore the uncrosslinked sealant may comprise devulcanized rubber and unvulcanized rubber made from the reclaimed rubber residue.

The rubber may be of all rubber types known to the person skilled in the art. Mixtures of different rubbers are also conceivable.

According to a preferred embodiment of the invention, the rubber in process step a) 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 brominated butyl rubber (BIIR) and/or chlorinated butyl rubber (CIIR).

These rubber types are particularly well suited for the processing temperatures in the production of tire sealants and subsequent use in tires.

Particularly preferably, at least butyl rubber (IIR) is used. Butyl rubber is particularly well suited because of its relatively high air impermeability.

It is clear to the person skilled in the art that all the mentioned ingredients in the crosslinked sealant are present at least partially in chemically modified form, in particular as derivatives.

In particular, by combining the crosslinking agent with the crosslinking initiator in a given amount according to the invention, a particularly effective tire sealant is obtained which seals rapidly in the event of failure, which is optimal for tires having a high internal pressure.

According to the invention, the self-sealing tire sealant contains 1.0 to 3.0 wt.% of at least one cross-linking agent. The amount of the at least one crosslinker is preferably from 1.5 to 3.0% by weight, particularly preferably from 1.5 to 2.5% by weight, based on the total amount of sealant.

According to a preferred embodiment of the invention, the crosslinking agent is selected from the group comprising (particularly preferably consisting of) polyhydroxymethyl resins and divinylbenzene and quinones. The quinone is preferably a quinone dioxime, such as dibenzoyl quinone dioxime or p-benzoquinone dioxime. Particularly preferred is p-benzoquinone dioxime.

With the preferred and particularly preferred crosslinking agents, extremely rapid crosslinking is achieved at relatively low temperatures. This enables the sealant to be quickly fixed in position after application of the material into the tire is achieved at the time of preparation of the sealant.

According to the invention, the self-sealing tire sealant contains 1.8 to 5.0 wt% of at least one crosslinking initiator.

The amount of the at least one crosslinking initiator is preferably from 2.0 to 4.0% by weight, particularly preferably from 2.5 to 3.5% by weight, based on the total amount of sealant.

The crosslinking initiator is a compound that initiates crosslinking of the sealant. The crosslinking initiator may be, for example and preferably, lead oxide or other metal oxides or peroxy compounds.

A peroxy compound is a compound comprising at least one peroxy compound unit (i.e., -O-) (wherein O ═ oxygen). A variety of peroxy compounds may also be used. The peroxy compound or compounds is/are preferably selected from the group consisting of diarylacyl peroxy compounds, diacyl peroxy compounds and peroxy esters.

The crosslinking initiator can be added as pure substance or in a mixture with, for example, a stabilizer. In the case of, for example, a mixture of 50% by weight of dibenzoyl peroxide and 50% by weight of dibutyl maleate as stabilizer, only the amount of peroxide contained is included in the amount of crosslinking initiator, i.e. for example such that no accompanying substances (such as dibutyl maleate) are included in the above-mentioned amount of the at least one crosslinking initiator.

The sealant may also comprise other ingredients such as, inter alia, fillers, binders, plasticizers, such as oil(s), and, where appropriate, other additives (such as pigments and/or zinc oxide and/or sulphur).

The plasticizer may be all plasticizers (especially oils) known to the person skilled in the art, such as especially aromatic, naphthenic or paraffinic mineral oil plasticizers, for example MES (mild extraction solvate) or RAE (residual aromatic extract) or TDAE (treated distillate aromatic extract), or rubber liquefied oil (RTL) or biomass liquefied oil (BTL), preferably having a polycyclic aromatic content of less than 3 wt% according to the IP 346 method. Mineral oil is particularly preferred as plasticizer.

When mineral oils are used, they are preferably selected from the group consisting of DAE (distilled aromatic extract) and/or RAE (residual aromatic extract) and/or TDAE (treated distilled aromatic extract) and/or MES (mild extraction solvent) and/or naphthenic oils.

According to a preferred embodiment of the invention, the sealant further comprises at least one filler, in particular at least one active filler.

The filler can be all fillers known to the person skilled in the art, such as, in particular, reinforcing fillers (for example carbon black and/or silica), wherein precipitated silica is particularly preferred and is known as a filler for tire rubber mixtures.

Furthermore, the sealant may comprise magnetic fillers, such as ferromagnetic metals, for example iron, nickel, cobalt, strontium, barium and gadolinium and/or compounds thereof (for example, in particular iron compounds, in particular iron oxides), such as magnetite (Fe)₃O₄) Or ferrite.

Furthermore, further reinforcing and non-reinforcing fillers can be envisaged, in particular fillers based on silica (such as silicates or sand or glass spheres), and if appropriate reinforcing fillers, such as graphite and graphene and so-called "carbon-silica dual-phase fillers", and also microspheres or regeneration residues of plastic particles or foams.

The term "carbon black" includes industrial carbon black and pyrolytic carbon black.

According to a preferred embodiment of the invention, the filler comprises at least one industrial carbon black. This has the advantage that the adhesion of the sealant is improved and the adhesion of the sealant is reduced during the manufacturing process. While improving the position fixity and tear resistance characteristics of the sealant.

Within the scope of the present invention, in principle all types of carbon blacks known to the person skilled in the art can be envisaged as carbon blacks.

According to one advantageous embodiment of the invention, carbon blacks are used which have an iodine adsorption number according to ASTM D1510 of from 20g/kg to 180g/kg, particularly preferably from 30g/kg to 140g/kg, and a DBP number according to ASTM D2414 of from 30ml/100g to 200ml/100g, preferably from 90ml/100g to 180ml/100g, particularly preferably from 110ml/100g to 180ml/100 g.

According to another preferred embodiment of the invention, carbon black of type N326 is used.

Mixtures of two or more carbon blacks are also contemplated.

According to another preferred embodiment of the invention, the filler comprises at least one silica (English: "silica").

Thereby, an optimal reinforcement of the sealant is achieved and good viscosity control and viscosity setting can be achieved. Furthermore, the adhesion of the sealant is increased by means of the at least one silicon dioxide and the adhesion of the sealant is reduced during the production process. While improving the position fixity and tear resistance characteristics of the sealant.

Mixtures of two or more silicas are also contemplated.

The silica may be one known to those skilled in the art to be suitable for use as a filler in tire rubber compounds.Thus, for example, Evonik corporation's silicon dioxide may be usedSilicas of the VN3 (trade name) type, with a relatively small BET surface area (for example from Solvay, Inc.), can also be used1115 or1085) As the silica, highly dispersible silica, so-called HD silica (e.g., Solvay's silica) can be used1165MP)。

Furthermore, mixtures of the fillers mentioned, such as, in particular, a combination of at least one industrial carbon black and at least one silica, can be envisaged and preferred, wherein the advantages mentioned are likewise obtained.

According to an advantageous embodiment of the invention, the amount of the at least one filler is 0.1 to 20 wt.%, preferably 2 to 12 wt.%, for example 5 to 10 wt.%, with respect to the total amount of sealant.

According to a particularly advantageous embodiment of the invention, the sealant comprises from 2.0% to 20% by weight, preferably from 2% to 12% by weight, of at least one filler selected from carbon black, silica and magnetic particles, wherein the carbon black comprises industrial carbon black and pyrolytic carbon black.

Particularly at low elongation, the sealant is reinforced with fillers such as carbon black and/or silica. In addition, the network temperature stability of the sealant is high.

The flow behavior of metal-piercing objects, such as in particular nails, can be optimized by means of magnetic particles.

According to another embodiment of the invention, no filler (i.e. 0 wt% filler) is included.

According to an advantageous embodiment, the sealant comprises at least one adhesive, in particular for the case where the sealant already has insufficient adhesion due to the components (in particular polymers) comprised. "adhesive" is understood in principle to mean any substance which increases the adhesion of the sealant.

The amount of the at least one binder is preferably from 2.0 to 20% by weight, referred to the total amount of sealant.

According to an advantageous embodiment of the invention, the binder is at least one hydrocarbon resin.

It will be clear to the skilled person that hydrocarbon resins are polymers formed from monomers wherein the hydrocarbon resin is formed by the inter-linking of monomers which are formally derivatives of the monomers.

Within the scope of the present application, the term "hydrocarbon resin" includes resins having carbon and hydrogen atoms and optionally may have heteroatoms (such as, in particular, oxygen atoms).

The hydrocarbon resin may be a homopolymer or a copolymer. In the present application, homopolymers are understood to be polymers which are on-line according to the abbreviation: (Online, taken from 2017, month 01, 02, the last article updated in 2008, month 8) "was generated from only one type of monomer.

Within the scope of the present invention, a copolymer is understood to be a polymer formed from a plurality (i.e. two or more) of different monomers. Within the scope of the present invention, the hydrocarbon resin may therefore also be a copolymer consisting of three different monomers, for example.

The monomers may be all monomers of hydrocarbon resins known to the person skilled in the art, such as aliphatic monomers (especially aliphatic C)₅Monomers), other cationically polymerizable, unsaturated compounds (including aromatic hydrocarbons and/or terpenes and/or alkenes and/or cycloalkenes).

Preferred monomers are in particular C₅Monomers and C₉A monomer.

The aromatic hydrocarbon (aromatic monomer) may be, for example, alpha-methylstyrene and/or styrene and/or vinyltoluene and/or indene and/or coumarone and/or methylindene and/or methyl coumarone and/or phenol.

The aromatic monomer is preferably alpha-methylstyrene and/or styrene and/or vinyltoluene and/or indene and/or coumarone and/or methylindene and/or methyl coumarone.

According to a little more generally, the term "alkene" is the radical name of "acyclic and cyclic aliphatic hydrocarbons having one or more reactive C ═ C double bonds in the molecule, which are now better referred to as alkenes or cycloalkenes, in a broader sense also the name … … of substituted derivatives thereof. Thus, within the scope of the present invention, unsaturated terpenes, alkenes and cycloalkenes are classified under the general concept "alkene".

The alkene may be, for example, 1-butene and/or 2-butene and/or butadiene.

According to a preferred embodiment of the invention, the hydrocarbon resin is at least one aliphatic resin, i.e. a resin which does not contain an aromatic ring system. This resin is composed of an aliphatic monomer or its derivative up to 100% by weight.

According to another embodiment of the invention, the resin consists of 10 to 99 wt.%, preferably 50 to 99 wt.%, particularly preferably 70 to 99 wt.% of aliphatic monomers and 1 to 90 wt.%, preferably 1 to 50 wt.%, particularly preferably 1 to 30 wt.% of aromatic monomers.

According to a preferred embodiment of the invention, the hydrocarbon resin is at least one resin selected from the group consisting of C₅Monomeric and known to the person skilled in the art as so-called C₅A resin of the resin. This achieves particularly good properties of the sealant, in particular at the same time as an optimized flow behavior with good adhesion.

Aliphatic C₅The monomer may be C₅Monomers of petroleum fractions (e.g. isoprene), and/or terpenes and/or cyclic olefins and/orMonomers of olefins such as pentene. C₅It is understood that these monomers are formed from five carbon atoms.

Furthermore, it is known to the person skilled in the art that, in addition to aliphatic monomers having five carbon atoms, C₅The petroleum fraction may also contain a hydrocarbon having, for example, four carbon atoms (i.e., C)₄Monomer) or six carbon atoms (C)₆Monomer) other aliphatic monomers (structural motifs).

According to an advantageous embodiment of the invention, the sealant comprises 2 to 20% by weight of at least one hydrocarbon resin as binder. The amount of the at least one hydrocarbon resin is preferably from 2 to 10% by weight, particularly preferably from 3.5 to 7% by weight.

With such preferred and particularly preferred amounts, the adhesion and viscosity of the sealant is further optimized.

According to an advantageous and exemplary embodiment of the invention, the sealant comprises the following ingredients in the following amounts:

10 to 30% by weight of at least one polyolefin, preferably at least one polybutene, and

-2.0 to 20% by weight of at least one binder, and

35 to 60% by weight of at least one rubber, and

-2.0 to 12% by weight of at least one filler, and

1.0 to 3.0% by weight of at least one crosslinking agent, and

-1.8 to 5.0 wt% of at least one crosslinking initiator.

The values given in% by weight relate accordingly to the total amount of sealant.

The tire sealant according to the present invention can be prepared from one or more components by methods known in the art. The mixing is preferably carried out in an extruder, preferably a twin-screw extruder.

Possible method steps and devices are disclosed, for example, in WO 2008/141848.

Another subject of the invention is a pneumatic vehicle tyre having, at least on the inner surface opposite to the tread, the tyre sealant according to the invention, including all the mentioned embodiments.

The layer thickness in the radial direction is in this case 2mm to 8mm, particularly preferably 3mm to 7mm, very particularly preferably 4mm to 5 mm.

The layer thickness is measured here in the radial direction perpendicular to the axial direction.

The mentioned layer thicknesses achieve an optimum balance of the sealing effect and at the same time do not, however, lead to high material consumption and high tire weights, which in turn has ecological advantages.

The sealant is composed of, for example:

52% by weight of a butyl rubber,

25% by weight of polybutene with a Mn of 1300g/mol,

5.0 wt% of an aliphatic hydrocarbon resin (C)₅A resin),

7.0% by weight of carbon black N326 as filler,

2.0% by weight of a crosslinking agent

3.0% by weight of a crosslinking initiator + 3.0% by weight of dibutyl maleate as stabilizer

3.0% by weight of a mineral oil plasticizer.