EP3258008A1 - Method for producing a reinforcing support, reinforcing support and vehicle tyre - Google Patents

Abstract

The invention relates to a method for producing a reinforcing layer of textile reinforcing materials for elastomeric products, wherein the method u.a. the dipping of the textile reinforcement in at least one first bath which contains at least one blocked diisocyanate and is free of free resorcinol and free formaldehyde and their precondensates, the protecting groups of the blocked diisocyanate (s) being selected from the group consisting of oximes, preferred ketoximes such as methyl ethyl ketoxime, and / or pyrazole derivatives such as preferably 3,5-dimethylpyrazole, and immersing the textile reinforcement in at least one second bath containing at least one malein-functionalized polymer and free of free resorcinol and free formaldehyde and their precondensates.

Furthermore, the invention relates to a vehicle tire which contains at least one reinforcement layer according to the invention.

Description

The invention relates to a method for producing a reinforcement layer for elastomeric products and to a reinforcement layer produced by the method. Furthermore, the invention relates to a vehicle tire which contains at least one reinforcement layer according to the invention.

Strength supports for reinforcing various elastomeric products are well known. Here, the reinforcements are usually surrounded by at least one rubber mixture, which is also called Gummierungsmischung. One problem is that the reinforcements and the surrounding rubber mixture have different strengths. In particular, with ongoing mechanical and dynamic stress, such as when used in a vehicle tire while driving, therefore, sufficient adhesion between the strength carrier and the surrounding gum mixture is necessary. In the prior art it is known to activate the strength members before the rubber coating for sufficient adhesion (adhesion activation), whereby usually so-called RFL dips (resorcinol-formaldehyde latex) are used, through which the strength members are immersed.
Furthermore, inter alia, blocked isocyanate and / or epoxy compounds in combination with RFL dips are used to further activate the strength carriers. The WO 2005/026239 A1 for example, discloses the use of polyisocyanates and RFL without epoxy compounds.

However, resorcinol and formaldehyde are classified as harmful to the environment and to health, so that one endeavors to provide alternatives for this purpose. This is what the EP 1745079 B1 as well as the DE 102014211365 A1 the treatment of textile fabric or textile reinforcements with a maleic-functionalized polymer to achieve improved adhesion to rubber compounds.
In the DE 102014211365 A1 Further, the use of caprolactam-blocked isocyanates is disclosed. However, such protective groups require relatively high temperatures for deprotection, so that the physical properties, in particular temperature-sensitive, textile reinforcements can be strongly influenced.

The present invention is based on the object to provide a method for producing a reinforcement layer comprising textile reinforcement, in which an influence on the physical properties of the textile reinforcement is avoided, at the same time the prepared reinforcement layer have an equal or even improved adhesion between reinforcements and gum mixture and also to be dispensed with environmentally and harmful substances.

1. a) Tauchen der textilen Festigkeitsträger in wenigstens einem ersten Bad, welches wenigstens ein geblocktes Diisocyanat enthält und frei ist von freiem Resorcin und freiem Formaldehyd sowie deren Vorkondensaten, wobei die Schutzgruppen des oder der geblockten Diisocyanat(e) ausgewählt sind aus der Gruppe bestehend aus Oximen, wie bevorzugt Ketoximen wie Methylethylketoxim, und/oder Pyrazol-Derivaten, wie bevorzugt 3,5-Dimethylpyrazol, und
2. b) Anschließendes Trocknen der Festigkeitsträger bei 120 bis 140 °C, und
3. c) Anschließendes Erhitzen der Festigkeitsträger auf 160 bis 200 °C, und
4. d) Tauchen der textilen Festigkeitsträger in wenigstens einem zweiten Bad, welches wenigstens ein Malein-funktionalisertes Polymer enthält und frei ist von freiem Resorcin und freiem Formaldehyd sowie deren Vorkondensaten, und
5. e) Anschließendes Trocknen der Festigkeitsträger bei 120 bis 155 °C, und
6. f) Anschließendes Erhitzen der Festigkeitsträger auf 210 bis 250 °C
7. g) Gummierung der mittels a) bis f) vorbehandelten textilen Festigkeitsträger mit einer Gummierungsmischung, die wenigstens einen Dienkautschuk, der ausgewählt ist aus der Gruppe bestehend aus natürlichem Polyisopren und/oder synthetischem Polyisopren und/oder Butadien-Kautschuk und/oder Styrol-Butadien-Kautschuk, und 20 bis 90 phr wenigstens eines Füllstoffes ausgewählt aus der Gruppe bestehend aus Ruß und/oder Kieselsäure enthält.

This object is achieved according to the invention by a process for producing a reinforcement layer for elastomeric products, the process comprising at least the process steps in the following sequence:

1. a) immersing the textile reinforcement in at least one first bath containing at least one blocked diisocyanate and is free of free resorcinol and free formaldehyde and their precondensates, wherein the protecting groups of the blocked diisocyanate or (e) are selected from the group consisting of oximes as preferred ketoximes such as methyl ethyl ketoxime, and / or pyrazole derivatives, such as preferably 3,5-dimethylpyrazole, and
2. b) Subsequent drying of the reinforcements at 120 to 140 ° C, and
3. c) then heating the reinforcements to 160 to 200 ° C, and
4. d) immersing the textile reinforcement in at least one second bath, which contains at least one malein-functionalized polymer and is free of free resorcinol and free formaldehyde and their precondensates, and
5. e) then drying the strength members at 120 to 155 ° C, and
6. f) Subsequently heating the reinforcements to 210 to 250 ° C
7. g) gumming of the textile reinforcements pretreated by means of a) to f) with a gumming composition comprising at least one diene rubber selected from the group consisting of natural polyisoprene and / or synthetic polyisoprene and / or butadiene rubber and / or styrene-butadiene rubber. Rubber, and 20 to 90 phr at least one filler selected from the group consisting of carbon black and / or silica.

Another object of the present invention is a reinforcement layer comprising textile reinforcement, which was prepared by the inventive method.

A further object on which the invention is based is to provide a vehicle tire which has a structural durability which is comparable to the state of the art, wherein environmentally and harmful substances are to be dispensed with in at least one reinforcement layer. It should thus be created at least one environmentally friendly alternative.

This object is achieved according to the invention by a vehicle tire, comprising in at least one component at least one reinforcement layer according to the invention, which was prepared by the method according to the invention.
By using the selection of protecting groups of the isocyanate compound in combination with the malein-functionalized polymer, it is possible to perform the adhesion activation of the reinforcements under comparatively mild conditions and to avoid affecting the physical properties of the textile reinforcements, since lower deprotection temperatures are required. At the same time, very good adhesion to the gumming mixture is achieved without the need for a standard RFL dip.

The vehicle tire is preferably a pneumatic vehicle tire.

According to the invention, the textile reinforcements in step a) are pretreated by immersion in at least one first bath, wherein the first bath contains at least one blocked diisocyanate and is free of free resorcinol and free formaldehyde and their precondensates, the protecting groups of the blocked diisocyanate (s ) are selected from the group consisting of oximes, such as preferably ketoximes such as methyl ethyl ketoxime, and / or pyrazole derivatives, such as preferably 3,5-dimethylpyrazole.
The textile reinforcements are still ungummed before and after this process step. The first bath is preferably an aqueous dispersion which may contain, in addition to water and the blocked diisocyanate, at least one epoxy compound such as glycerol triglyceride ether and / or bisphenol A diglycidyl ether and / or 2,3-epoxybutyl azidoformate and / or sorbitol polyglycidyl ether.
According to a preferred embodiment of the invention, the first bath contains at least one epoxy compound, preferably glycerol triglyceride ether, which is known, for example, under the trade name Grilbond® G 1701. Dipping in the reinforcement in this first bath is carried out in a manner known to those skilled in the art. Such a treatment step is also referred to as pre-dip.
The first bath is free of free resorcinol and free formaldehyde and their precondensates, ie it contains 0 to 0.01 wt .-%, but preferably 0 wt .-%, of such substances.

In the context of the present invention, blocked diisocyanates are understood to mean molecules which carry two blocked, ie protected, terminal isocyanate groups or formally arise by condensation of molecules with two isocyanate groups. These may be monomers, dimers, trimers or higher homologues of the diisocyanates.

Examples of diisocyanate monomers are methylenediphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), isophorone diisocyanate.

Diisocyanate trimers or higher homologs are grouped together as polyisocyanates and are compounds having three or more terminal isocyanate groups. They arise z. B. formally by condensation of three or more molecules, each with two isocyanate groups (diisocyanates). Formally, the condensation usually takes place via in each case one isocyanate group of each molecule, so that the polyisocyanates correspondingly have three or more isocyanate groups which are blocked only by a protective group and are available for further chemical reactions after / during the removal of the protective group , Because z. B. the 1,6-hexamethylene diisocyanate trimer formally formed by condensation of three 1,6-hexamethylene diisocyanate molecules on each one isocyanate group of the diisocyanates, the 1,6-hexamethylene diisocyanate trimer has three (leftover) terminal isocyanate groups on.
As is known to those skilled in the art, the higher homologues of the precondensed isocyanates give, depending on the degree of condensation, average functionalities of greater than three.
The isocyanates can then be present as a mixture of different molecules with different functionalities, wherein the average number of terminal isocyanate groups corresponds to the average functionality.
This so-called isocyanate number is determined by titration as known to the person skilled in the art (ISO 14896/3, see Metrohm, Application Bulletin 200/3 e;
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Preferably, the blocked diisocyanate has a functionality greater than 2. According to an advantageous embodiment of the invention, the blocked diisocyanate is a blocked polyisocyanate having a functionality of greater than or equal to 3, particularly preferably 3 to 5, very particularly preferably 3 to 4, for example, in particular 3.3. Here, the blocked polyisocyanate is preferably selected from the group consisting of blocked 1,6-hexamethylene diisocyanate trimer (HDI) and its blocked higher homologues and blocked toluene diisocyanate trimer and its blocked higher homologues as well as blocked isophorone diisocyanate trimer and its blocked higher homologs.
More preferably, the blocked polyisocyanate is blocked 1,6-hexamethylene diisocyanate trimer or blocked toluene diisocyanate trimer, most preferably 1,6-hexamethylene diisocyanate trimer.

The protecting groups of the blocked diisocyanate (s) are selected from the group consisting of oximes, such as preferably ketoximes such as methyl ethyl ketoxime, and / or pyrazole derivatives, such as preferably 3,5-dimethylpyrazole.
Oxime and pyrazoles require a comparatively low temperature for cleaving off the protective groups, so that in the process according to the invention in particular temperature-sensitive textile reinforcements are spared.
Preferably, the protecting groups of the blocked diisocyanate (s) are selected from the group consisting of methyl ethyl ketoxime (MEKO), and / or 3,5-dimethylpyrazole (DMP).
Protecting groups of blocked isocyanates known in the art, such as the caprolactam group, require comparatively high deprotection temperatures, which may affect the physical properties of the textile reinforcements. However, the deprotection temperature must not be so low that the deprotection already takes place during the drying in process step b), s. below. Therefore, malonates do not constitute suitable protecting groups in the process of the invention.

According to a particularly advantageous embodiment of the invention, the blocked polyisocyanate in process step a)
Methyl ethyl ketoxime blocked 1,6-hexamethylene diisocyanate trimer or 3,5-dimethylpyrazole blocked 1,6-hexamethylene diisocyanate trimer.

This results in combination with the maleic polymer from step d) particularly good adhesive properties, which also can be dispensed with environmentally and harmful substances.

Subsequent to process step a), the reinforcements in process step b) are dried at 120 to 140 ° C. In this case, the temperature must not be too high, so that there is no deprotection of the blocked isocyanates, to prevent an undesirable side reaction with the evaporating (residual) water. The duration of the drying step b) is preferably 30 to 120 seconds.

After drying, the dried reinforcements in process step c) are heated to 160 to 200 ° C to deprotect the isocyanates. It is essential to the invention that the diisocyanates carry the protective groups mentioned in process step a), so that heating to more than 200 ° C. can be dispensed with. This protects the textile reinforcement and avoids an influence that adversely affects the subsequent adhesion to the rubber compound. At the same time, the method according to the invention is comparatively energy-saving, but nevertheless a very good adhesion is achieved, at the same time waiving environmental and harmful substances.

The heating time in step c) is preferably 30 to 120 seconds.

According to the invention, the reinforcements in process step d) are treated by being dipped in at least one second bath, the second bath containing at least one malein-functionalized polymer and being free of free resorcinol and free formaldehyde and their precondensates.
A maleic-functionalized polymer is a polymer which carries maleic groups as functional groups by reaction with maleic acid and / or maleic anhydride. A maleic-functionalized polymer is, for example, under the trade name Ricobond ^® 7004 Cray Valley available as an aqueous dispersion.

The second bath is preferably an aqueous dispersion which preferably contains at least one VP latex (vinyl pyridine latex, typically 15% vinyl pyridine, 15% styrene and 70% butadiene) in addition to water and the malein functionalized polymer. According to a preferred embodiment of the invention, the aqueous dispersion consists of 90 to 99.9 wt .-% of water, VP latex and said maleic polymer. The aqueous dispersion here preferably comprises 40 to 90% by weight of water and 5 to 40% by weight of VP latex and 1 to 10% by weight of the said maleic polymer. The VP latex is likewise preferably used as aqueous dispersion, the above quantities being based on anhydrous VP latex, or the water content contained in the VP latex dispersion already having been added to the total amount of water of the aqueous dispersion.

Like in the EP 1745079 B1 discloses arise from malein-functionalized polymers by reaction with amines imide functionalities and thus maleimide polymers. Since not all malein groups have to be converted into imide groups, the resulting maleimide polymer has both maleic groups and imide groups.

The terms "group" and "functionalization" are used synonymously in the context of the chemical characteristics of the polymers used.

The maleic polymer used preferably has a molecular weight of 5,000 to 20,000 g / mol, particularly preferably 5,000 to 15,000 g / mol, very particularly preferably 7,000 to 13,000 g / mol, again very particularly preferably 10,500 to 13,000 g / mol. With such a molecular weight of the maleic polymer, sufficient adhesion to the strength member results, and the workability of the dispersion is good.

The maleic-functionalized polymer described above, according to a preferred embodiment of the invention, is a polybutadiene.

The second bath according to step d) is free of free resorcinol and free formaldehyde and their precondensates, i. it contains from 0 to 0.01% by weight, but preferably 0% by weight, of such substances.

In particular, the combination of the dipping containing the maleic polymer according to step d) with said pre-dip containing the selection of blocked diisocyanates according to step a) leads to very good adhesion results of reinforcing agents to the respective surrounding gum mixture, the advantages also and in particular by avoiding influencing the physical properties of the textile materials. Compared to known in the art RFL pretreatments a sufficient level of adhesion is achieved, which is dispensed with environmentally and harmful substances.

Subsequent to process step d), the reinforcements in process step e) are dried at 120 to 155 ° C. Again, this step is to first remove water so that it does not lead to side reactions in subsequent reactions. The duration of the drying step e) is preferably 30 to 120 seconds.

Following the drying in step e), the dried reinforcements are heated to 210 to 250 ° C. in process step f). This serves to react the deprotected substances from the first bath in step a) with the substances from the second bath in step d). Preferably, the heating time in process step f) is 30 to 120 seconds.

All of the described drying steps and steps for heating the reinforcements are carried out in devices known to those skilled in the art, such as in particular 1- or 2-zone furnaces, through which the reinforcements are preferably passed continuously.

The strength carriers treated by means of process steps a) to f) are, according to the invention, in process step g) with at least one gumming mixture gummed, ie encased. The gum mixture for this purpose contains at least one diene rubber selected from the group consisting of natural polyisoprene and / or synthetic polyisoprene and / or butadiene rubber and / or styrene-butadiene rubber, and 20 to 90 phr of at least one filler selected from the group consisting of carbon black and / or silica.

In the following, the ingredients of the gum mixture are explained in more detail. All embodiments also apply to the reinforcement layer according to the invention, which was produced by the method according to the invention and the vehicle tire having the reinforcement layer according to the invention in at least one component. It is clear to the person skilled in the art that the constituents, in particular the rubbers, are chemically modified in the vulcanized tire.

These may be all diene rubbers of the abovementioned group known to the person skilled in the art.
The gum mixture may contain polyisoprene (IR, NR) as the diene rubber. These may be both cis-1,4-polyisoprene and 3,4-polyisoprene. However, preference is given to the use of cis-1,4-polyisoprenes having a cis-1,4 content of> 90% by weight. First, such a polyisoprene can be obtained by stereospecific polymerization in solution with Ziegler-Natta catalysts or using finely divided lithium alkyls. On the other hand, natural rubber (NR) is such a cis-1,4-polyisoprene, the cis-1,4-content in natural rubber is greater than 99% by weight.
If the rubber mixture contains polybutadiene (BR) as the diene rubber, these may be either cis-1,4- or vinyl-polybutadiene (about 10-90% by weight vinyl content). Preference is given to the use of cis-1,4-polybutadiene with a cis-1,4 content greater than 90 wt .-%, which z. By solution polymerization in the presence of rare earth type catalysts.

As further diene rubbers styrene-butadiene copolymers can be used. The styrene-butadiene copolymers may be solution-polymerized styrene-butadiene copolymers (S-SBR) having a styrene content, based on the polymer, of about 10 to 45 wt .-% and a vinyl content (content of 1,2-bound butadiene, based on the total polymer) of 10 to 70 wt. %, which can be prepared using, for example, lithium alkyls in organic solvent. The S-SBR can also be coupled and end-group modified. However, it is also possible to use emulsion-polymerized styrene-butadiene copolymers (E-SBR) and mixtures of E-SBR and S-SBR. The styrene content of the E-SBR is about 15 to 50% by weight, and the types known in the art obtained by copolymerization of styrene and 1,3-butadiene in aqueous emulsion can be used.

The diene rubbers used in the mixture, in particular the styrene-butadiene copolymers, can also be used in a partially or fully functionalized form. The functionalization can be carried out with groups that can interact with the fillers used, in particular with OH-bearing fillers. It may be z. B. functionalizations with hydroxyl groups and / or epoxy groups and / or siloxane groups and / or amino groups and / or phthalocyanine groups and / or carboxy groups and / or silane-sulfide groups act.

The gum mixture preferably contains from 25 to 100 phr, particularly preferably from 50 to 100 phr, again particularly preferably from 70 to 100 phr of natural polyisoprene and / or synthetic polyisoprene, in which case natural polyisoprene is preferred.

According to a preferred embodiment of the invention, the gumming mixture contains 100 phr of at least one natural polyisoprene (NR) and / or synthetic polyisoprene (IR), whereby a mixture of NR and IR is conceivable.

According to a further preferred development of the invention, the gumming mixture contains 25 to 85 phr of at least one natural and / or synthetic polyisoprene and 15 to 50 phr of at least one butadiene rubber and / or 15 to 50 phr of at least one styrene-butadiene rubber. Especially with these rubbers For example, particularly in reinforcing layers of vehicle tires, very good physical properties of the rubberizing mixture are evident in terms of processability, durability and tear properties while achieving a satisfactory level of adhesion.

The term phr (parts per hundred parts of rubber by weight) used in this document is the quantity used in the rubber industry for mixture formulations. The dosage of the parts by weight of the individual substances is always based on 100 parts by weight of the total mass of all the rubbers present in the mixture. The mass of all rubbers present in the mixture adds up to 100.

The gum mixture may contain as fillers carbon blacks and / or silicic acids, the fillers may be used in combination and the total amount of carbon black and silica is 20 to 90 phr. Preferably, 30 to 90 phr, particularly preferably 50 to 70 phr, of at least one carbon black are used.

According to an advantageous embodiment of the invention, the gumming mixture contains 50 to 100 phr of at least one natural and / or synthetic polyisoprene and 30 to 90 phr of at least one carbon black. This results in a particularly good structural durability of the reinforcement layer produced, especially when used in vehicle tires.

Furthermore, in small amounts, 0 to 10 phr, according to a preferred embodiment of 0.1 to 10 phr, further fillers such as aluminosilicates, chalk, starch, magnesium oxide, titanium dioxide or rubber gels may be included.
Furthermore, it is conceivable that the rubber mixture carbon nanotubes (CNT) including discrete CNTs, so-called hollow carbon fibers (HCF) and modified CNT containing one or more functional groups, such as hydroxyl, carboxyl and carbonyl groups).
Graphite and graphene as well as so-called "carbon-silica dual-phase filler" are conceivable as filler.

However, the gum mixture is preferably free of these further fillers, ie it preferably contains 0 to 0.001 phr of these further fillers.
Zinc oxide is not considered a filler in the present invention.

When carbon black is used in the gum mixture, it is preferably those types having an STSA surface area (in accordance with ASTM D 6556) of more than 30 m ² / g, preferably 30 to 120 m ² / g. These can be easily incorporated and ensure low heat build-up.

According to a preferred development of the invention, the gumming mixture contains at least one carbon black having an iodine adsorption number according to ASTM D 1510 of 40 to 110 g / kg and an STSA surface (according to ASTM D 6556) of 40 to 120 m ² / g. With such a carbon black, in particular due to the comparatively high surface area, a sufficient reinforcement and strength of the rubberizing mixture is achieved in order to balance the differences in strength between reinforcements and rubber of the rubbering mixture as well as possible. A possible preferred type of carbon black is, for example, carbon black N326 having an iodine adsorption number according to ASTM D 1510 of 82 g / kg and an STSA surface (according to ASTM D 6556) of 76 m ² / g. Another possible preferred type of carbon black is, for example, carbon black N660 having an iodine adsorption number according to ASTM D 1510 of 36 g / kg and an STSA surface (according to ASTM D 6556) of 34 m ² / g.

If silicas are present in the mixture, these may be the silicas customary for tire rubber mixtures. It is particularly preferred when a finely divided, precipitated silica is used which has a CTAB surface area (according to ASTM D 3765) of 30 to 350 m ² / g, preferably from 120 to 250 m ² / g. As silicic acids it is possible to use both conventional silica such as VN3 (trade name) from Evonik and highly dispersible silicas, so-called HD silicas (eg Ultrasil 7000 from Evonik). Silicas are preferably used in amounts of less than 15 phr.

• -SCN, -SH, -NH₂ oder -S_x- (mit x = 2 bis 8).

So können als Silan-Kupplungsagenzien z. B. 3-Mercaptopropyltriethoxysilan, 3-Thiocyanato-propyltrimethoxysilan oder 3,3'-Bis(triethoxysilylpropyl)polysulfide mit 2 bis 8 Schwefelatomen, wie z. B. 3,3'-Bis(triethoxysilylpropyl)tetrasulfid (TESPT), das entsprechende Disulfid (TESPD) oder auch Gemische aus den Sulfiden mit 1 bis 8 Schwefelatomen mit unterschiedlichen Gehalten an den verschiedenen Sulfiden, verwendet werden. TESPT kann dabei beispielsweise auch als Gemisch mit Industrieruß (Handelsname X50S® der Firma Evonik) zugesetzt werden.
Bevorzugt wird ein Silan-Gemisch eingesetzt, welches zu 40 bis 100 Gew.-% Disulfide, besonders bevorzugt 55 bis 85 Gew.-% Disulfide und ganz besonders bevorzugt 60 bis 80 Gew.-% Disulfide enthält. Ein solches Gemisch ist z.B. unter dem Handelsnamen Si 261® der Firma Evonik erhältlich, welches z.B. in der DE 102006004062 A1 beschrieben ist. Auch geblockte Mercaptosilane, wie sie z. B. aus der WO 99/09036 bekannt sind, können als Silan-Kupplungsagens eingesetzt werden. Auch Silane, wie sie in der WO 2008/083241 A1 , der WO 2008/083242 A1 , der WO 2008/083243 A1 und der WO 2008/083244 A1 beschrieben sind, können eingesetzt werden. Verwendbar sind z. B. Silane, die unter dem Namen NXT in verschiedenen Varianten von der Firma Momentive, USA, oder solche, die unter dem Namen VP Si 363® von der Firma Evonik Industries vertrieben werden. Ferner ist es denkbar, dass eines der oben genannten Mercaptosilane, insbesondere 3-Mercaptopropyltriethoxysilan, in Kombination mit Verarbeitungshilfsmitteln (die unten aufgeführt sind), insbesondere PEG-Carbonsäureester, eingesetzt werden.
Gemäß einer bevorzugten Ausführungsform der Erfindung enthält die Gummierungsmischung eine Kombination aus 3-Mercaptopropyltriethoxysilan und PEG-Carbonsäureester, wodurch besonders gute Eigenschaften ergeben, und zwar insbesondere im Hinblick auf die zu lösende technische Aufgabe sowie insgesamt ein gutes Eigenschaftsniveau hinsichtlich der sonstigen Eigenschaften.
Weiterhin kann die Gummierungsmischung weitere Aktivatoren und/oder Agenzien für die Anbindung von Füllstoffen, insbesondere Ruß, enthalten. Hierbei kann es sich beispielsweise um die z.B. in der EP 2589619 A1 offenbarte Verbindung S-(3-Aminopropyl)Thioschwefelsäure und/oder deren Metallsalze handeln, wodurch sich insbesondere bei der Kombination mit wenigstens einem Ruß als Füllstoff sehr gute physikalische Eigenschaften der Gummierungsmischung ergeben.To improve the processability and to attach the silica and other optional polar fillers to the diene rubber silane coupling agents can be used in rubber mixtures. Here, one or more different silane coupling agents can be used in combination with each other. The gum mixture may thus contain a mixture of different silanes.
The silane coupling agents react with the superficial silanol groups of the silica or other polar groups during the mixing of the rubber or the rubber mixture (in situ) or even before the addition of the filler to the rubber in the sense of a pretreatment (pre-modification). All silane coupling agents known to the person skilled in the art for use in rubber mixtures can be used as silane coupling agents. Such known from the prior art coupling agents are bifunctional organosilanes having on the silicon atom at least one alkoxy, cycloalkoxy or phenoxy group as a leaving group and have as other functionality a group which may optionally undergo a chemical reaction with the double bonds of the polymer after cleavage , In the latter group may be z. For example, they may be the following chemical groups:

• -SCN, -SH, -NH ₂ or -S _x - (where x = 2 to 8).

Thus, as silane coupling agents z. For example, 3-mercaptopropyltriethoxysilane, 3-thiocyanato-propyltrimethoxysilane or 3,3'-bis (triethoxysilylpropyl) polysulfides having 2 to 8 sulfur atoms, such as. For example, 3,3'-bis (triethoxysilylpropyl) tetrasulfide (TESPT), the corresponding disulfide (TESPD) or mixtures of the sulfides having 1 to 8 sulfur atoms with different contents of the various sulfides, are used. For example, TESPT can also be added as a mixture with carbon black (trade name X50S® from Evonik).
Preference is given to using a silane mixture which comprises 40 to 100% by weight of disulfides, particularly preferably 55 to 85% by weight of disulfides and very particularly preferably 60 to 80% by weight of disulfides. Such a mixture is available, for example, under the trade name Si 261® Evonik, which, for example, in the DE 102006004062 A1 is described. Also blocked mercaptosilanes, as z. B. from the WO 99/09036 are known, can be used as a silane coupling agent. Also silanes, as in the WO 2008/083241 A1 , of the WO 2008/083242 A1 , of the WO 2008/083243 A1 and the WO 2008/083244 A1 can be used, can be used. Suitable for. B. silanes, which are sold under the name NXT in different variants by the company Momentive, USA, or those sold under the name VP Si 363® by Evonik Industries. Furthermore, it is conceivable that one of the abovementioned mercaptosilanes, in particular 3-mercaptopropyltriethoxysilane, can be used in combination with processing aids (which are listed below), in particular PEG-carboxylic acid esters.
According to a preferred embodiment of the invention, the gum mixture contains a combination of 3-mercaptopropyltriethoxysilane and PEG carboxylic acid ester, which gives particularly good properties, in particular with regard to the technical problem to be solved and overall good property level with respect to the other properties.
Furthermore, the gumming mixture can contain further activators and / or agents for the binding of fillers, in particular carbon black. This may be, for example, the example in the EP 2589619 A1 disclosed compound S- (3-aminopropyl) thiosulfuric acid and / or their metal salts, resulting in very good physical properties of the gumming especially when combined with at least one carbon black as a filler.

From 0 to 70 phr, preferably from 0.1 to 60 phr, of at least one plasticizer may be present in the gum mixture. These include all plasticizers known to those skilled in the art, such as aromatic, naphthenic or paraffinic mineral oil plasticizers, such as, for example, MES (mild extraction solvate) or TDAE (treated distillate aromatic extract), or rubber-to-liquid oils (RTL) or biomass-to-liquid. Oils (BTL, as used in the DE 10 2008 037714 A1 disclosed)) or oils based on renewable raw materials (such as rapeseed oil, terpene oils (eg orange oils) or Faktisse or plasticizer resins or liquid polymers (such as liquid BR) whose average molecular weight (determination by GPC = gel permeation chromatography, based on BS ISO 11344: 2004) is between 500 and 20000 g / mol Gum mixture Liquid polymers used as plasticizers are not included as rubber in the calculation of the composition of the polymer matrix (phr calculation).
When using mineral oil, this is preferably selected from the group consisting of DAE (Distilled Aromatic Extracts) and / or RAE (Residual Aromatic Extract) and / or TDAE (Treated Distilled Aromatic Extracts) and / or MES (Mild Extracted Solvents) and / or naphthenic oils.

1. A) Alterungsschutzmittel, wie z. B. N-Phenyl-N'-(1,3-dimethylbutyl)-p-phenylendiamin (6PPD), N,N'-Diphenyl-p-phenylendiamin (DPPD), N,N'-Ditolyl-p-phenylendiamin (DTPD), N-Isopropyl-N'-phenyl-p-phenylendiamin (IPPD), 2,2,4-Trimethyl-1,2-dihydrochinolin (TMQ) und andere Substanzen, wie sie beispielsweise aus J. Schnetger, Lexikon der Kautschuktechnik, 2. Auflage, Hüthig Buch Verlag, Heidelberg, 1991, S. 42-48 bekannt sind,
2. B) Aktivatoren, wie z. B. Zinkoxid und Fettsäuren (z. B. Stearinsäure),
3. C) Wachse,
4. D) Harze, insbesondere Klebharze, die keine Weichmacherharze sind,
5. E) Methylenakzeptoren, wie Resorcin und Resorcinäquivalente, und/oder Methylendonor/Formaldehydspender, wie z. B. Hexamethoxymethylmelamin (HMMM) und/oder Hexamethylentetramin (HMT)
6. F) Mastikationshilfsmittel, wie z. B. 2,2'-Dibenzamidodiphenyldisulfid (DBD) und
7. G) Verarbeitungshilfsmittel, wie z.B. Fettsäuresalze, wie z.B. Zinkseifen, und Fettsäureester und deren Derivate, wie z.B. PEG-Carbonsäureester.

Furthermore, the gum mixture may contain conventional additives in conventional parts by weight. These additives include

1. A) anti-aging agents, such. N-phenyl-N '- (1,3-dimethylbutyl) -p-phenylenediamine (6PPD), N, N'-diphenyl-p-phenylenediamine (DPPD), N, N'-ditolyl-p-phenylenediamine (DTPD ), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) and other substances, such as those of J. Schnetger, Encyclopedia of Rubber Technology, 2nd edition, Hüthig Book Verlag, Heidelberg, 1991, pp. 42-48 are known,
2. B) activators, such. Zinc oxide and fatty acids (eg stearic acid),
3. C) waxes,
4. D) Resins, in particular tackifier resins which are not plasticizer resins,
5. E) methylene acceptors, such as resorcinol and resorcinol equivalents, and / or methylene donor / formaldehyde donors, such as. Hexamethoxymethylmelamine (HMMM) and / or hexamethylenetetramine (HMT)
6. F) Mastikationshilfsmittel such. B. 2,2'-Dibenzamidodiphenyldisulfid (DBD) and
7. G) processing aids, such as fatty acid salts, such as zinc soaps, and fatty acid esters and their derivatives, such as PEG carboxylic acid ester.

The vulcanization is carried out in the presence of sulfur and / or sulfur donors, with some sulfur donors can also act as a vulcanization accelerator. Sulfur or sulfur donors are added in the last mixing step in the amounts customary by the skilled person (0.4 to 8 phr, sulfur, preferably in amounts of 0.4 to 4 phr) of the gum mixture. The vulcanization can also be done in Presence of very low amounts of sulfur in combination with sulfur-donating substances done.

Furthermore, the gum mixture may contain vulcanization-affecting substances such as vulcanization accelerators, vulcanization retarders and vulcanization activators in conventional amounts in order to control the time and / or temperature of vulcanization required and to improve the vulcanizate properties. The vulcanization accelerators may be selected, for example, from the following groups of accelerators: thiazole accelerators such as. B. 2-mercaptobenzothiazole, sulfenamide accelerators such as. B. benzothiazyl-2-cyclohexylsulfenamid (CBS), guanidine accelerators such as. N, N'-diphenylguanidine (DPG), dithiocarbamate accelerators such as. As zinc dibenzyldithiocarbamate, disulfides, thiophosphates. The accelerators can also be used in combination with each other, which can result in synergistic effects.

The preparation of the gum mixture is carried out in a conventional manner, wherein first of all a masterbatch containing all constituents except for the vulcanization system (sulfur and vulcanization-affecting substances) is prepared in one or more mixing stages followed by the addition of the curing system is produced. Subsequently, the mixture is processed further.

The gumming of the reinforcement in step g) also takes place in a manner known to those skilled in the art.

In the following, the properties of the textile reinforcement are explained in more detail. All embodiments are valid for the inventive method, the reinforcement layer according to the invention and the vehicle tire according to the invention.

The textile reinforcements preferably comprise polyethylene terephthalate (PET) and / or polyethylene naphthalate (PEN) and / or polybutylene terephthalate (PBT) and / or Polycarbonate (PC) and / or cellulose and / or cellulose ester and / or m-aramid and / or p-aramid and / or a mixture of m-aramid and p-aramid and / or a polyamide which is selected from the group of polyamide 46 (PA 4.6) and / or polyamide 410 (PA 4.10) and / or polyamide 6 (PA 6) and / or polyamide 66 (PA 6.6 polyhexamethylene adipamide) and / or polyamide 612 (PA 6.12) and / or polyamide 1010 ( PA 10.10) and / or polyamide 1212 (PA 12.12).

The textile reinforcements particularly preferably comprise polyethylene terephthalate (PET) and / or cellulose and / or cellulose esters and / or polyamide 66 (PA 6.6 polyhexamethylene adipamide).

The textile reinforcement are preferably cords having at least one twisted yarn.
In this case, all known in the prior art subtleties (titer in the unit dtex) and twisting of the cords and yarns are conceivable. It is expedient if the denier of each yarn is between 200 and 5000 dtex and if the twist of the yarns and cords is between 100 and 800 t / m.
The textile reinforcing materials preferably have the stated properties already before process step a), ie they are preferably first twisted and then treated with process steps a) to g).
In the event that the textile reinforcing elements are embedded as a tissue in the rubberizing mixture, preferably after twisting and before the treatment according to the process steps a) to f), as known to those skilled in a weaving step.

According to a preferred development of the invention, the reinforcing members are cords of a respective yarn, with which a twisted yarn represents a cord in each case.

According to a further preferred development of the invention, the strength carriers are cords of at least two, more preferably two, yarns.

According to a further preferred embodiment of the invention, the reinforcement layer according to the invention or that of the vehicle tire according to the invention cords from different numbers of yarns as reinforcement.

The reinforcement layer according to the invention can be used in all components of a vehicle tire, which contain reinforcements, resulting in the above-mentioned advantages in terms of substances and the production and sufficient adhesion. These components are, in particular, the carcass ply and / or the belt (in the belt layer or layers) and / or the belt bandage and / or the bead reinforcement.

The advantages described above are also achieved in the use of the above-described reinforcement layer for the production of other elastomeric products, such as conveyor belts, drive belts, hoses and bellows.

The invention will now be explained in more detail with reference to the following examples.

Inventive Example 1 (E1): Nylon cords as textile reinforcements, pre-dip containing DMP-blocked HDI trimer, dip containing maleic polymer

Of nylon cords made of two nylon yarns having a thickness of 940 dtex (940 x 2) were passed through a pre-dip containing 84.05 wt .-% water and 2.01 wt .-% Grilbond ^® G 1701 and 13 , 94% by weight of Acrafix PCI (DMP-blocked HDI trimer, solids content about 31.5% by weight). Subsequently, the cords were dried for 30 to 120 seconds at 140 ° C and then heated to 200 ° C.
These cords were then dipped through another dip bath containing 54 wt% water and 42.4 wt% VP latex (40 wt% VP polymer in water, ie 17 wt% VP Latex in the dip) and 3.6% by weight of RICOBOND 7004, Cray Valley (30% by weight of maleic polymer in water: mean value from manufacturer's data 25 to 35% by weight). It was then dried again for 30 to 120 seconds at 150 ° C and then heated to 235 ° C.

Inventive Example 2 (E2): Nylon cords as textile reinforcements, pre-dip containing MEKO-blocked HDI trimer, dip containing maleic polymer

Of nylon cords made of two nylon yarns having a thickness of 940 dtex (940 x 2) were passed through a pre-dip containing 88.35 wt .-% water and 1.29 wt .-% Grilbond ^® G 1701 and 10 wt .-% EDOLAN ^® XCIB (MEKO blocked HDI-trimer) immersed 36th Subsequently, the cords were dried for 30 to 120 seconds at 140 ° C and then heated to 200 ° C.
These cords were then dipped through another dip bath containing 54 wt% water and 42.4 wt% VP latex (40 wt% VP polymer in water, ie 17 wt% VP Latex in the dip) and 3.6% by weight of RICOBOND 7004, Cray Valley (30% by weight of maleic polymer in water: mean value from manufacturer's data 25 to 35% by weight). It was then dried again for 30 to 120 seconds at 150 ° C and then heated to 235 ° C.

Comparative Example 1 (V1): Nylon cords as textile reinforcement, Pre-dip containing caprolactam blocked MDI, dip containing maleic polymer

The cords of Comparative Example 1 (V1) was prepared analogously to E1, except that instead of Acrafix PCI (DMP blocked HDI-trimer) Crilbond ^® IL-6 (caprolactam-blocked MDI) was used. The pre-dip containing 93.5 wt .-% water and 3.42 wt .-% ^® Grilbond IL-6 and 3.08 wt .-% Grilbond ^® G 1701. The first drying step was carried out at 165 ° C and then Heat to 225 ° C as caprolactam requires a higher temperature for deprotection over the DMP protecting group.

For all the cords, the process step of drying involving hot drawing was undisturbed, ie, as known to those skilled in the art. This serves to adjust the properties, such as elongation at break, elongation at break and heat shrinkage of the cord by targeted stretching to the desired level. wherein the tension applied to the cord is varied between tension and relaxation.

Comparison of liability examples (E1 and E2) vs. Comparative Example 1 (V1)

Adhesive tests, so-called peel tests, according to ISO 36: 2011 (E) with evaluation in accordance with DIN ISO 6133 without aging were carried out with the differently treated cords. For this purpose, the strength carrier cords were rubberized with an uncured gum mixture having the composition according to Table 1 (according to process step g)) and then vulcanized. The gumming takes place by placing the cords on or between calendered thin rubber sheets of the gumming compound and then compressing the entire specimen in the heating press.

Then, the force for peeling off the mixture from the cords was determined (adhesion), and the coverage of the cords with mixture after peeling was optically determined. 5 means complete coverage, 0 means no rubber remains on the cord.

The results of the adhesion tests are shown in Table 2. Table 1: Components of the gum mixture ingredients Quantity (phr) NR / IR 70 BR / SBR 30 Soot N660 50 Processing oil / adhesive resin 5 Other additives ^a) 8th Resin from resorcinol and formaldehyde donor 5 Sulfur and accelerator 3.3

a) anti-aging agent, ZnO, stearic acid

Table 2 property unit V1 E1 E2 liability N / 25mm 188 168 182 covering (1 to 5) 4.5 4.5 4.7

The reinforcement layer produced by means of the method according to the invention shows, as can be seen in Table 2, a comparable durability, since the adhesion of the reinforcements to the rubber mixture is comparable, the method according to the invention being more energy-saving and gentler for the textile reinforcements. Further, in the example of the invention, the disadvantages associated with free resorcinol and formaldehyde in the dip are avoided.

Claims (13)

Process for producing a reinforcement layer comprising textile reinforcement for elastomeric products, the method comprising at least the steps in the following order: a) immersing the textile reinforcement in at least one first bath containing at least one blocked diisocyanate and is free of free resorcinol and free formaldehyde and their precondensates, wherein the protecting groups of the blocked diisocyanate or (e) are selected from the group consisting of oximes as preferred ketoximes such as methyl ethyl ketoxime, and / or pyrazole derivatives, such as preferably 3,5-dimethylpyrazole, and b) Subsequent drying of the reinforcements at 120 to 140 ° C, and c) then heating the reinforcements to 160 to 200 ° C, and d) immersing the textile reinforcement in at least one second bath, which contains at least one malein-functionalized polymer and is free of free resorcinol and free formaldehyde and their precondensates, and e) then drying the strength members at 120 to 155 ° C, and f) then heating the reinforcements to 210 to 250 ° C, and g) gumming of the textile reinforcements pretreated by means of a) to f) with a gumming composition comprising at least one diene rubber selected from the group consisting of natural polyisoprene and / or synthetic polyisoprene and / or butadiene rubber and / or styrene-butadiene rubber. Rubber, and 20 to 90 phr at least one filler selected from the group consisting of carbon black and / or silica. A method according to claim 1, characterized in that the diisocyanate has a functionality of greater than 2, preferably greater than or equal to 3. A method according to claim 2, characterized in that the diisocyanate is a polyisocyanate selected from the group consisting of blocked 1,6-hexamethylene diisocyanate trimer and its blocked higher homologues and blocked toluene diisocyanate trimer and its blocked higher homologs and blocked isophorone diisocyanate trimer and its blocked higher homologs. A method according to claim 3, characterized in that the polyisocyanate is selected from the group consisting of methyl ethyl ketoxime blocked 1,6-hexamethylene diisocyanate trimer and 3,5-dimethylpyrazole blocked 1,6-hexamethylene diisocyanate trimer. Method according to one of the preceding claims, characterized in that the maleic polymer has a molecular weight of 5000 to 20,000 g / mol. Method according to one of the preceding claims, characterized in that the first bath according to process step a) comprises at least one epoxy compound. Method according to one of the preceding claims, characterized in that the polymer in step d) is a maleic-functionalized polybutadiene. Method according to one of the preceding claims, characterized in that the textile reinforcement polyethylene terephthalate (PET) and / or polyethylene naphthalate (PEN) and / or polybutylene terephthalate (PBT) and / or polycarbonate (PC) and / or cellulose and / or cellulose esters and / or m-aramid and / or p-aramid and / or a mixture of m-aramid and p-aramid and / or a polyamide which is selected from the group consisting of polyamide 46 (PA 4.6) and / or polyamide 410 (PA 4.10 ) and / or polyamide 6 (PA 6) and / or polyamide 66 (PA 6.6 polyhexamethylene adipamide) and / or polyamide 612 (PA 6.12) and / or polyamide 1010 (PA 10.10) and / or polyamide 1212 (PA 12.12). Method according to one of the preceding claims, characterized in that the gumming mixture contains 50 to 100 phr of at least one natural and / or synthetic polyisoprene and 30 to 90 phr of at least one carbon black. Method according to one of the preceding claims, characterized in that the carbon black of the gumming mixture has an iodine adsorption number according to ASTM D 1510 of 40 to 110 g / kg and an STSA surface (according to ASTM D 6556) of 40 to 120 m ² / g. Reinforcing layer for elastomeric products, wherein it is produced by at least one method according to one of claims 1 to 10. Vehicle tire comprising at least one reinforcement layer according to claim 11 in at least one component. Vehicle tire according to claim 12, characterized in that it comprises the reinforcement layer at least in the carcass ply and / or the belt bandage and / or the belt and / or the bead reinforcement.