Extrusion template and method

Abstract

The invention relates to an extrusion template (10) for use during the extrusion of rubber products, comprising: a) a template body (12), b) a template recess (16) which passes through the template body (12) along an extrusion direction E and which is delimited by peripheral wall surfaces (14), and c) an elongated injector element (18) which extends through the template recess (16) between the wall surfaces (14) along the injector direction I, comprising an injection gap (20), wherein the extrusion template (10) is designed to produce a material gap in a material strand extruded through the template recesses (16) along the extrusion direction E by means of the injector element (18) and to inject an injection composition into the material gap through the injection gap (20) in order to bring the extruded material strand into contact with the injection composition at the walls. The extrusion template (10) comprises at least one distributing depression (22) which is wider than the injection gap (20) along the transverse direction Q, and the extrusion template (10) is designed such that an injection composition injected into the material gap can enter the distributing depression (22) such that the material strand extruded in a guided manner via the distributing depression (22) can contact the injection composition on the outer face.

Description

[0001] Extrusion template and process

[0002] Description

[0003] The invention relates to an extrusion template for use in the extrusion of rubber products, an extrusion system comprising this extrusion template, a process for producing a strand-shaped vulcanizable rubber product that can be carried out by extrusion, a process based thereon for producing a vulcanized rubber product, and a vulcanized rubber product produced by this process.

[0004] A key component of modern pneumatic vehicle tires, which in many cases is significantly responsible for the performance characteristics of these products, is the tread. Today, treads usually consist of several different components, particularly various rubber materials, which can be obtained by vulcanization from vulcanizable rubber compounds. Such treads are regularly produced by coextrusion of various vulcanizable rubber compounds and, in terms of their structure, can usually be conveniently described by their cross-section, which, apart from any influences from the tread pattern, is usually uniform throughout the entire tread.

[0005] In cross-sectional view, most treads, especially those used on cars and trucks, comprise one or more rubber materials intended to come into contact with the road surface during later use, and whose properties are optimized for this purpose. This layer, which essentially acts as a top layer, is made from a vulcanizable rubber compound, sometimes referred to as a "cap compound," which often contains large amounts of non-electrically conductive fillers, such as precipitated silica. A base layer (often referred to as a "base") is usually located beneath the rubber material intended for road contact.In the majority of cases, this basis serves primarily to create sufficient adhesion between the cover layer intended for road contact and the other parts of the pneumatic vehicle tyre, so that a high bond strength between the tread and the other components of the pneumatic vehicle tyre can be ensured.

[0006] Those skilled in the art are aware that for the vast majority of applications, a tread as a whole must exhibit a certain degree of electrical conductivity to prevent unwanted static charging. However, in many cases, the rubber material of the top layer does not possess sufficient electrical conductivity to ensure this.

[0007] Therefore, the electrical conductivity of the entire tread in the prior art is usually achieved by the base mixture of the underlying base, which has increased electrical conductivity, particularly as a result of a high carbon black content. For this purpose, for example, a material strand is guided from the base to the upper side of the tread, thereby creating an electrically conductive connection between the surface of the tread and the base. The electrically conductive base mixture is usually formed up to the surface of the tread by a pre-template in the extruder. The corresponding structure is also referred to as a "carbon center beam" (CCB). Information on the technological background is disclosed, for example, in DE 4445758 B4, DE 69717958 T2, EP 1792720 A2, NL 2006420 C2 and US 2018170123 A1.

[0008] However, the formation of a CCB from the vulcanizable rubber compound of the underlying base is often considered disadvantageous from a manufacturing perspective, for example, with regard to the number of extruder heads required, the often complex flow guidance within the extruder head, and the material requirements. Furthermore, the "base" compound is generally not intended for road contact, so the resulting partial coverage of the tread surface with "base" compound is sometimes also perceived as disadvantageous in terms of driving characteristics. Furthermore, some treads do not even have a suitable "base" compound with which a CCB could be realized, so the connection between the underside of the tread and the surface must be formed using an additional extruder.

[0009] Against this background, there is a need in the field of technology to provide tread designs that have sufficient electrical conductivity while showing as little influence of the CCB on the driving characteristics as possible.

[0010] For this purpose, devices and processes have been developed that make it possible to create a particularly thin conductive area during tread production. This conductive area extends radially through the tread in the final vehicle tire and is advantageously sufficient to reliably prevent static charging. These new concepts are based on incorporating an electrically conductive rubber compound into the tread during the molding of the vulcanizable rubber compounds by applying a thin layer to the side surface of the extruded strands.To form the side surface to be coated, the extruded tread can, for example, be cut in its longitudinal direction, as disclosed in DE 102007039100 A1, or only a part of a tread is directly extruded, which, after the corresponding coating, is combined with other parts to form the tread, as disclosed, for example, in DE 102007039101 A1. Further disclosures of this approach can be found, for example, in EP 2520421 B1 and EP 3253553 B1. Depending on the requirements of the technology used in each case, electrically conductive rubber mixtures or suitable precursors of such a conductive rubber mixture can be used as injection compositions as electrically conductive materials for the coating, in particular solutions or dispersions in evaporable solvents, so that coating from an advantageously flowable solution is possible.

[0011] The inventors have recognized that, in principle, those embodiments are preferred in which a very thin conductive web is formed using this method, i.e., when—depending on the viscosity of the conductive rubber mixture used—a thickness of less than 20 μm is set, for example. This not only minimizes the influence of the web on the driving characteristics, but also, in particular, enables reliable joining of the tread parts separated before coating, which, in the inventors' opinion, cannot always be sufficiently guaranteed with significantly thicker webs. At the same time, the inventors have recognized that corresponding thicknesses are sufficient to dissipate static electricity.

[0012] However, when using a correspondingly thin ridge, the contact area on the underside and topside of the tread becomes very small, as the corresponding CCB has only a very small cross-sectional area. The reduction is so pronounced for preferred thin ridges compared to conventional CCBs that there is a risk that the otherwise desirable reduction in surface coverage by the conductive material will be excessive, and reliable contact with the substrate can no longer be sufficiently ensured in all situations.This problem is further exacerbated by the fact that, due to manufacturing constraints, there is a risk that the rubber elements flanking the thin CCB will deform at the interface during further processing, for example, during vulcanization under pressure, to such an extent that the thin CCB lying between them is concealed by the flanking rubber elements, or that these flanking rubber elements form a depression between them into which the CCB is sunk and consequently does not reach the tire surface. In these cases, a suitable CCB on a new tire cannot fulfill its intended function because it does not provide a sufficient guide path to the road surface.

[0013] It was the primary object of the present invention to eliminate or at least reduce the disadvantages of the prior art.

[0014] In particular, it was an object of the present invention to provide a method for producing a strand-shaped vulcanizable rubber product, in particular a tread, as well as devices and systems designed for this method, with which particularly thin webs made of conductive material can be introduced into the strand-shaped vulcanizable rubber product, which, despite the small cross-sectional area, should ensure safe accessibility and easy electrical contacting of the web on the top and / or bottom side of the strand-shaped vulcanizable rubber product.

[0015] It was a further object of the present invention that the specified method, devices, and systems should enable advantageous vulcanizable or vulcanized rubber products to be produced, in particular treads that have a very thin CCB and consequently exhibit excellent rolling properties. In this respect, it was an object of the present invention that the vulcanizable or vulcanized rubber products should enable reliable dissipation of electrical charge despite the thin CCB, wherein, in the case of treads, reliable contact with the road surface and / or underlying tire components should be ensured, especially in new tires whose tread surface has not yet been altered by abrasion.

[0016] Furthermore, it was an object of the present invention that the method to be specified should require less mechanical effort and / or have a lower material requirement compared to the prior art.

[0017] Furthermore, it was a supplementary object of the present invention that the method to be specified should be as time- and cost-efficient as possible.

[0018] It was a further object of the present invention to provide advantageous vulcanized rubber products that can be produced using the methods, devices and systems to be specified.

[0019] The inventors of the present invention have now found that the above-described objects can be achieved if, in contrast to the methods known from the prior art, not only a thin, electrically conductive modification layer is produced in the strand-shaped vulcanizable rubber product by means of an injection composition, but if, in addition, a surface coating is also produced by the conductive material on at least one side, which during the extrusion by specific

[0020] Distribution depressions in the extrusion template can be achieved, as defined in the claims. This advantageously produces a thin, electrically conductive surface layer locally in a very time- and cost-efficient process, which is reliably bonded to the thin CCB and ensures a large contact area, with the rolling properties of the tire being only slightly altered by the relatively small and thin surface modification. The above-mentioned objects are thus achieved by the subject matter of the invention, as defined in the claims. Preferred embodiments of the invention emerge from the subclaims and the following explanations.

[0021] Such embodiments, which are designated as preferred below, are combined in particularly preferred embodiments with features of other embodiments designated as preferred. Combinations of two or more of the embodiments designated as particularly preferred below are thus very particularly preferred. Likewise preferred are embodiments in which a feature of one embodiment designated as preferred to any extent is combined with one or more further features of other embodiments designated as preferred to any extent. Features of preferred extrusion systems, processes, and vulcanized rubber products result from the features of preferred extrusion templates.

[0022] The advantageous vulcanized rubber products of the present invention can be obtained using the process according to the invention. The process according to the invention relies on the use of an extrusion system according to the invention, which is significantly characterized by an extrusion template according to the invention, which enables the process to be carried out according to the invention and thus the obtainment of vulcanized rubber products according to the invention. Thus, the subject matters of the present invention are closely related. For a clear explanation of the present invention, it is expedient to begin the disclosure of the invention with the extrusion template according to the invention.

[0023] The invention accordingly relates firstly to an extrusion template for use in the extrusion of rubber products, comprising: a) a template body, b) a template recess penetrating the template body along an extrusion direction E and delimited by circumferential wall surfaces, and c) an elongated injector element extending between the wall surfaces along the injector direction I through the template recess, with an injection gap, wherein the extrusion template is designed to create a material gap through the injector element in a material strand extruded along the extrusion direction E through the template recesses and to inject an injection composition into the material gap through the injection gap in order to contact the extruded material strand with the injection composition on the walls of the material gap,wherein the extrusion template comprises at least one distribution recess in the wall surface of the template recess, wherein the distribution recess is wider than the injection gap along the transverse direction Q perpendicular to the extrusion direction E and perpendicular to the injector direction I, and wherein the extrusion template is configured to allow an injection composition injected through the injection gap into the material gap to enter the distribution recess, so that the extruded material strand guided over the distribution recess can be contacted with the injection composition present in the distribution recess on the outer side of the material strand guided along the wall surface.

[0024] The extrusion template according to the invention is suitable for use in the extrusion of rubber products. Extrusion templates are widely known to those skilled in the rubber processing industry. Extrusion templates are often divided by those skilled in the art into so-called pre-templates and end-templates, which express the position in the extrusion system at which they are used. Pre-templates usually initially guide the rubber strands into closer spatial proximity, for which purpose they usually comprise several recesses, each of which serves to guide a rubber strand. In contrast, end-templates usually have only one recess through which the individual rubber strands of the pre-template are guided.The extrusion template according to the invention is particularly suitable for use as a final template, since in this way a conductive web can be formed through the entire strand-shaped rubber product, on the surface of which an advantageous conductive region is simultaneously formed, via which the electrical charge can be dissipated. An example of an extrusion template according to the invention is shown, wherein the extrusion template is a preliminary template, wherein the extrusion template comprises two or more, preferably three or more, template recesses penetrating the template body along the extrusion direction E. However, the extrusion template according to the invention is preferred, wherein the extrusion template is a final template, wherein the extrusion template preferably comprises exactly one template recess.

[0025] Due to the specific requirements placed on treads for pneumatic vehicle tires, the extrusion templates according to the invention are particularly suitable for use in the production of these rubber products. Thus, an extrusion template according to the invention is preferred, wherein the extrusion template is for use in the extrusion of treads for vehicle tires.

[0026] Analogous to extrusion templates known from the prior art, the extrusion template according to the invention initially comprises a template body. This term refers to the workpiece in which the various template recesses of the extrusion template are arranged. An example of an extrusion template according to the invention is one in which the template body is made of metal, preferably steel.

[0027] The template recesses in the template body serve to guide the extruded material through the extrusion template. In the context of the present invention, the direction in which the material to be extruded is guided through the extrusion template is referred to as the extrusion direction E. The shape of the template recess correlates with the desired cross-sectional shape of the extruded material strand. For the extrusion of treads, trapezoidal cross-sections have proven particularly suitable. Accordingly, an extrusion template according to the invention is preferred, wherein the template recess has a polygonal cross-section, preferably a quadrangular cross-section, particularly preferably a trapezoidal cross-section, in the plane perpendicular to the extrusion direction E.

[0028] Since the stencil body will have a non-negligible thickness, a recess penetrating the stencil body is necessarily bounded by surrounding wall surfaces. A circular stencil recess, for example, would be bounded by only one surrounding wall surface, whereas a rectangular stencil recess would comprise four distinguishable individual wall surfaces as the surrounding wall. In this respect, an extrusion stencil according to the invention is preferred, wherein the stencil recess is bounded by four or more, preferably exactly four, wall surfaces.

[0029] With regard to the above-described components a) and b), the extrusion template according to the invention corresponds in principle to the extrusion templates known from the prior art. However, the extrusion template according to the invention now also comprises an injector element with an injection gap, which extends between the wall surfaces of the template recess, so that it runs through the template recess. In the context of the present invention, the direction along which the injector element runs from one wall surface to the other is referred to as the injector direction I.

[0030] The injector element in extrusion templates according to the invention primarily serves two purposes. The injector element extending through the template recess serves, firstly, to split the material strand extruded through the template recess by blocking part of the template recess. This creates a material gap in the extrusion direction behind the injector element, which acts as a flow obstruction. The injector element then serves to inject an injection composition into the material gap through an injection gap pointing in the direction of this material gap. This allows the extruded material strand to come into contact with the injection composition at the walls exposed by the splitting. Those skilled in the art will understand that this is thus an extrusion template according to the invention, wherein the injector element is configured to be able to inject an injection composition through the injection gap.

[0031] To implement the desired injection function, it is expedient to connect the injector element to a supply of injection compositions, for example, via lines. Accordingly, an extrusion template according to the invention is relevant for most cases, wherein the injector element is fluidly connected or connectable to a fluid supply device, wherein the fluid supply device preferably comprises a pump device and a reservoir for storing an injection composition.

[0032] With regard to the arrangement of the injector element, in the case of template recesses with a polygonal cross-section, it is particularly preferred for the injector element to extend between opposing parts of the wall. Thus, an extrusion template according to the invention is preferred, wherein the injector element extends from one wall surface of the template recess to an opposite wall surface.

[0033] The person skilled in the art understands that the template recess is divided into two parts by the injector element, wherein, in view of the properties of the strand-shaped rubber products that can be produced therewith, it is, in the inventors' opinion, particularly advantageous to position the injector element as centrally as possible so that the conductive coating introduced by the injector element in the strand-shaped rubber product also runs as centrally as possible. An extrusion template according to the invention is preferred, wherein the injector element is positioned in the template recess such that, when viewed from above along the extrusion direction E, the template recess is divided by the injector element into two partial areas, the areas of which differ by 50% or less, preferably by 30% or less, particularly preferably by 10% or less, particularly preferably by 5% or less.

[0034] In order to ensure the most controlled possible splitting of the material strand around the injector element and a robust construction of extrusion templates according to the invention, the inventors consider it expedient to arrange the injector element as centrally as possible, also with respect to the extrusion direction, so that a wall of the extrusion template remains in front of and behind the injector element in the extrusion direction, through which the extruded material can be guided. Accordingly, an extrusion template according to the invention is preferred, wherein the injector element is positioned in the template recess such that the injector element is spaced from both outlet openings of the template recess along the extrusion direction E by a distance that differs by 50% or less, preferably by 30% or less, particularly preferably by 10% or less, particularly preferably by 5% or less.

[0035] The desired splitting of the extruded material strand can, in principle, be achieved with any shape of obstacle that divides the template recess into two or more regions, so that, for example, injector elements with a round cross-section are also suitable, which then have a cylindrical shape. However, in the inventors' opinion, it is particularly advantageous if a controlled splitting of the material strand is promoted by providing a wedge shape or a similar taper, which promotes the separation along the flanks of the wedge, which in particular improves the flow behavior of the extruded material strand. Accordingly, an example of an extrusion template according to the invention is one in which the injector element is at least partially cylindrical, preferably over the entire length of the part of the injector element running in the template recess.However, an extrusion template according to the invention is preferred, wherein the injector element tapers on the side facing away from the injection gap opposite to the extrusion direction E, preferably in a drop-shaped manner.

[0036] At least in theory, it is possible to arrange the injector element obliquely in the extrusion template with respect to the extrusion direction, so that the extruded material strand contacts the injector element earlier in one section and later in another section with respect to the extrusion direction. Even if such a configuration is conceivable, the inventors believe that this does not provide advantages that would justify the additional design effort. Rather, the inventors believe that good results can be achieved particularly well if the injector element, and thus the injection direction I, are essentially orthogonal to the extrusion direction, so that the extruded material strand is split by the injector element essentially orthogonal to the extrusion direction E.Thus, an extrusion template according to the invention is preferred, wherein the injector direction I encloses an angle in the range of 70° to 110°, preferably an angle in the range of 80° to 100°, particularly preferably in the range of 85° to 95°, very particularly preferably of substantially 90°, with the extrusion direction E, and / or wherein the injector element and the wall surfaces in the contact region enclose an angle in the range of 70° to 110°, preferably an angle in the range of 80° to 100°, particularly preferably in the range of 85° to 95°, very particularly preferably of substantially 90°.

[0037] Depending on the subsequent arrangement of the extrusion template and thus depending on the gravity acting during use, it is fundamentally unnecessary to extend the injection gap over the entire length of the injector element, since, depending on the volume flow of the injection composition, it is possible for the injection composition exiting through a shorter injection gap to sufficiently fill the material gap to contact the extruded material strand over its entire height at the walls, which is particularly preferred. In view of this preferred embodiment, however, the inventors consider it particularly advantageous if the injection gap also extends essentially over the entire length over which the coating is to be applied, since this enables a significantly more controlled and precise application of the injection composition into the material gap and onto its walls.Accordingly, an extrusion template according to the invention is preferred, wherein the injection gap extends over the entire length of the part of the injector element running in the template recess.

[0038] Within the scope of the present invention, the mode of operation is mostly described with reference to the presence of precisely one injector element, whereby an extrusion template according to the invention, which comprises precisely one injector element, is correspondingly suitable for the production of strand-shaped rubber products comprising precisely one CCB. In this respect, however, the inventors propose that the extrusion templates according to the invention can also be designed such that they can be used to form several thin CCBs in the extruded material. Accordingly, an extrusion template according to the invention is preferred for certain applications, wherein the extrusion template comprises two or more, preferably three or more, preferably identical, injector elements.

[0039] The person skilled in the art will understand that in the method according to the invention, which is carried out with extrusion templates according to the invention, after the material strand has been separated and the walls of the material gap have subsequently been brought into contact with the injection composition, the previously separated parts of the material strand are brought together and joined again, thereby closing the material gap. This joining can be achieved, for example in the case of a preliminary template according to the invention, by a downstream end template. However, particularly with end templates, it is also possible for the length of the template recess in the extrusion direction E to be selected to be so large that the joining of the material gap can still take place within the extrusion template according to the invention when the extruded material extends further along the walls of the template recess in the extrusion direction behind the injection element.Such a joining region of the template recess can also comprise a section which has an at least slightly reduced overall cross-section than the template recess at the level of the injector element, so that the two split parts of the material strand are pressed together by a corresponding taper. In this case, an extrusion template according to the invention is preferred, wherein the extrusion template comprises a joining region spaced apart from the injector element along the extrusion direction E, wherein the extrusion template is configured to close the material gap created in the extruded material strand in the joining region by joining the walls of the material gap contacted with the injection composition, wherein the joining region is preferably formed by a joining section of the template recess in which the template recess tapers along the extrusion direction E.

[0040] In this respect, the inventors propose suitable dimensions for typical template recesses, which are particularly suitable for the formation of tread components. The dimensions of the template recess in the extrusion template according to the invention can expediently be defined using the previously defined directions. The extent along the extrusion direction E determines the depth of the template recess. Within the scope of the present invention, the injector direction I, which is usually orthogonal to the extrusion direction E, is understood as the height of the template recess. Furthermore, within the scope of the present invention, the transverse direction Q is defined, which is orthogonal to the extrusion direction E and the injector direction I. In the particularly preferred case of a non-inclined arrangement of the injector element in the template recess, the three directions E, I, and Q thus correspond to the axes of a Cartesian coordinate system.Preferred is an extrusion template according to the invention, wherein the template recess is an elongated template recess and has a diameter in the range from 4 to 40 mm, preferably in the range from 5 to 30 mm, particularly preferably in the range from 6 to 10 mm, along the injector direction I. Additionally or alternatively, preferred is an extrusion template according to the invention, wherein the template recess is an elongated template recess and has a diameter in the range from 5 to 500 mm, particularly preferably in the range from 6 to 450 mm, very particularly preferably in the range from 8 to 400 mm, along the transverse direction Q, wherein the specific dimensions are oriented in particular to the products to be manufactured, so that extrusion templates for the extrusion of truck treads will have larger dimensions than those for bicycle treads.Additionally or alternatively, an extrusion template according to the invention is also preferred, wherein the template recess along the extrusion direction E has a diameter in the range from 3 to 30 mm, particularly preferably in the range from 4 to 15 mm, very particularly preferably in the range from 5 to 8 mm.

[0041] Furthermore, the inventors also propose suitable dimensions for the injector element and the width of the injection gap, which allow good results in the formation of the material gap and uniform contacting of the corresponding walls to be achieved when processing typical vulcanizable rubber mixtures and injecting a wide range of injection compositions. An extrusion template according to the invention is preferred, wherein the injector element has an average diameter along the transverse direction Q in the range of 3 to 40 mm, particularly preferably in the range of 4 to 20 mm, and most preferably in the range of 6 to 10 mm.Additionally or alternatively, an extrusion template according to the invention is also preferred, wherein the injector gap along the transverse direction Q has an average diameter in the range from 0.1 to 2.0 mm, particularly preferably in the range from 0.2 to 1.0 mm, very particularly preferably in the range from 0.5 to 0.8 mm.

[0042] The particularly advantageous properties of extrusion templates according to the invention result in particular from the use of one or more special recesses in the wall surfaces of the template recess, which are referred to as distribution recesses in the context of the present invention because they serve to receive the injection composition injected from the injector element into the material gap and to enable the material strand pressed over this distribution recess to be contacted from the outside with the injection composition accumulated in the distribution recess, so that the injection composition is quasi distributed.

[0043] Due to the presence of these distribution depressions, not only the subsequently rejoined walls are contacted with the injection composition, but also a part of the area that will later represent the surface of the extruded material strand, whereby the fluid-conducting connection between the material gap and the distribution depression ensures that in the extruded material strand the coated surface areas and the thin conductive web, which can be formed virtually simultaneously, are reliably connected to each other.

[0044] In this respect, the person skilled in the art understands that the injector element will cast a flow shadow in the extrusion direction E, so that the material gap has a certain volume. Accordingly, it would not be expedient to make the distribution recess so small that it lies entirely within the area of ​​the material gap, since in this case it could not be covered by the split parts of the material strand. Consequently, the distribution recess is at least wider than the injection gap along the transverse direction Q. How wide the distribution recess actually is in the transverse direction will depend in later practice significantly on the properties of the processed vulcanizable rubber mixture, the extrusion speed, and the geometric design of the injector element acting as a flow obstacle, since these factors in particular determine the dimensions of the resulting material gap.For the extrusion process envisaged by the person skilled in the art, the distribution recess should have a larger area in the area orthogonal to the injector direction I than the cross-section of the resulting material gap, whereby the actual dimensions are also determined by the width of the surface modification that the person skilled in the art wants to achieve via the distribution recess.

[0045] For a given extruder system with a specific vulcanizable rubber mixture, the skilled person can readily identify suitable dimensions of the distribution recess in light of the invention and, if necessary, optimize them in routine experiments. The complex dependence of the design of the extrusion template according to the invention on the subsequent intended use is taken into account within the scope of the present invention in that the extrusion template, as defined above, is configured to allow the injector composition injected into the material gap to penetrate into the distribution recess to contact the extruded material strand guided over the distribution recess.

[0046] In principle, an extrusion template according to the invention is preferred, wherein the distribution recess is wider than the injection gap transversely to the extrusion direction E and transversely to the injector direction I by a factor of 2 or more, preferably by a factor of 5 or more, particularly preferably by a factor of 10 or more, very particularly preferably by a factor of 20 or more. Additionally or alternatively, an extrusion template according to the invention is also preferred, wherein the distribution recess is wider than the injector element transversely to the extrusion direction E and transversely to the injector direction I by a factor of 1.25 or more, preferably by a factor of 1.5 or more, particularly preferably by a factor of 2 or more, very particularly preferably by a factor of 5 or more.Additionally or alternatively, an extrusion template according to the invention is also preferred, wherein the distribution recess along the transverse direction Q preferably has an average diameter in the range from 0.1 to 2 mm, particularly preferably in the range from 0.2 to 1.0 mm, very particularly preferably in the range from 0.3 to 0.7 mm. The extrusion template according to the invention comprises at least one distribution recess. The person skilled in the art will understand that this can be used to form a corresponding surface coating on one side of the injector element and thus on one side of the CCB produced in the material strand, as described above. In the inventors' opinion, this is already sufficient for some applications, for example to ensure good road surface contact for the CCB in the case of a tread.At the same time, however, the inventors consider it preferable for essentially all embodiments if two distribution recesses are provided in order to form a corresponding modification region on both sides of the surface of the extruded strand.Even if it is theoretically possible to realize the functionality of a single distribution opening described above by combining two separate distribution openings that extend, for example, to the left and to the right of the injector element, the person skilled in the art will readily understand that the two distribution recesses should preferably be arranged in the walls at opposite ends of the injector element so that a strand of material extruded through the extrusion template is provided with an associated surface coating on both sides of the thin, conductive web so that in the case of a tread, for example, not only excellent road contact but also a reliable connection with underlying layers of the tread can be ensured.For essentially all embodiments, an extrusion template according to the invention is also preferred, wherein the extrusion template comprises at least one, preferably identical, distribution depression in the opposite wall surface of the template recess in the contact area with the injector element, wherein the extrusion template is designed so that a material injected through the injection gap into the material gap.

[0047] Injection composition can enter the distribution recesses so that the extruded material strand guided over the distribution recesses can be contacted with the injection composition present in the distribution recesses on the outer sides of the material strand guided along the wall surfaces.

[0048] Even if a more sophisticated fluid guide may make it possible to arrange the distribution recesses such that they extend at least partially upstream of the injector element with respect to the extrusion direction E, the inventors believe that, for the most reliable contact possible between the produced CCB and the conductive surface coatings, it is expedient to provide the distribution recesses and the injection gap on the same side of the injector element. Accordingly, an extrusion template according to the invention is preferred, wherein the distribution recess is arranged on the side of the injector element in the wall surface of the template recess that encompasses the injection gap.

[0049] At least theoretically, it is conceivable that the distribution recess is spaced at least somewhat apart from the injector element along the extrusion direction E. However, according to the inventors, it is preferred for essentially all configurations if the distribution recess directly adjoins the injector element in the extrusion direction E. In particular, configurations in which part of the side wall of the distribution recess is formed by parts of the injector element are also preferred. An extrusion template according to the invention is preferred, wherein the side wall of the distribution recess is partially formed by the injector element.

[0050] During the design of extrusion templates according to the invention, it has been shown that it is unproblematic if the distribution recesses have a sharp edge at the upstream end in the extrusion direction, since the extruded material mixture usually slides over them without any problems. However, depending on the design of the materials used and the dimensions of the distribution recesses, the material strand may partially sink into the distribution recess when passing over it. If a very sharp edge is also provided on the downstream side, as would be achieved, for example, with a completely square recess, this edge of the distribution recess can slow down the sunken part of the material strand and lead to unwanted changes or obstructions in the material and flow behavior.To avoid this, the inventors propose that the side of the distribution recess facing in the extrusion direction E should be as flat as possible in order to guide any parts of the material strand that have sunk into the distribution recess back to the original extrusion path without excessive resistance. Accordingly, an extrusion template according to the invention is preferred, wherein the depth of the distribution recess decreases along the extrusion direction E with increasing distance from the injector element. Additionally or alternatively, an extrusion template according to the invention is also preferred, wherein the distribution recess is flattened along the extrusion direction E pointing away from the injector element.Additionally or alternatively, an extrusion template according to the invention is preferred, wherein the distribution recess has a triangular or trapezoidal cross-section, preferably a triangular cross-section, in a plane lying parallel to the extrusion direction E.

[0051] As a particularly preferred embodiment of extrusion templates according to the invention, the inventors propose that the injector element can be designed to be replaceable. For this purpose, complementary openings or recesses into which an injector element can be inserted can be provided on opposite sides of the wall. The injector insertion opening can, for example, be designed as a bore through the template body, so that the injector element can be guided through the bore into the template recess until it is arranged on the opposite side in the injector receiving recess and is fixed there, for example, in a form-fitting manner. This advantageously makes it possible to match the choice of injector elements to the materials to be processed, for example with regard to the shape of the injector element and / or the design of the respective injection gap.Accordingly, an extrusion template according to the invention is preferred, wherein the extrusion template comprises an injector receiving recess and an injector insertion opening in the wall surfaces of the template recess, wherein the injector element extends through the injector insertion opening into the injector receiving recess, wherein the extrusion template is designed such that the injector element is reversibly and non-destructively replaceable, wherein the one or more distribution recesses are preferably formed by a part of the injector insertion opening and / or the injector receiving recess.

[0052] In a further development of the reversibly and non-destructively replaceable injector elements, the inventors propose that a plurality of complementary insertion openings and receiving recesses can also be provided. This allows the extrusion template according to the invention to be used in various injector positions, for example, to achieve greater flexibility with regard to the positioning of the CCB in the tread pattern without having to produce a new extrusion template, whereby the position of the CCB can be adapted, for example, to the desired profile. In such embodiments, the inventors believe it is expedient to close the unused injector insertion openings or injector receiving recesses with suitable closure elements, for example, with a form-fitting rubber plug.Consequently, an extrusion template according to the invention is preferred, wherein the extrusion template comprises two or more, preferably three or more, particularly preferably four or more, complementary injector insertion openings and injector receiving recesses in the wall surfaces of the template recess for receiving an injector element in different injector positions, wherein at least some of the injector positions, preferably all of the injector positions, are assigned at least one, preferably at least two opposite distribution recesses, wherein the injector element extends in an injector position through the corresponding injector insertion opening into the corresponding injector receiving recess, wherein the extrusion template is designed so that the position of the injector element can be changed reversibly and non-destructively between the injector positions.Particularly preferred is an extrusion template according to the invention, wherein the extrusion template additionally comprises one or more closure elements for closing, preferably positively closing, injector insertion openings and injector receiving recesses of injector positions not occupied by an injector element and / or of distribution recesses assigned to these injector positions.

[0053] The invention also relates to an extrusion system comprising: aa) at least one extruder, and bb) at least one extrusion template according to the invention.

[0054] The extrusion template according to the invention can be combined essentially with all suitable, typical extruders commercially available from various suppliers. The positioning of the extrusion template according to the invention in the extrusion system will depend in particular on its design as a pre-template or final template. An example of an extrusion system according to the invention is one in which the extrusion system additionally comprises an additional pre-template arranged between the extrusion template and the extruder or an additional final template arranged on the side facing away from the extruder. The additional pre-template and the additional final template preferably do not comprise an injector element.Additionally or alternatively, an extrusion system according to the invention is also exemplary, wherein the extrusion system additionally comprises a joining element arranged on the side facing away from the extruder and having a joining region, wherein the extrusion system is configured to close the material gap produced in the extruded material strand in the joining region by joining the walls of the material gap contacted with the injection composition, wherein the joining element is preferably formed by an additional end template arranged on the side facing away from the extruder.

[0055] The invention further relates to a method for producing a strand-shaped vulcanizable rubber product, with an extrusion system according to the invention, comprising the method steps: i) extruding a material strand of at least one vulcanizable rubber mixture with an extruder through the extrusion template according to the invention along the extrusion direction E, wherein a material gap is created in the material strand by the injector element, ii) injecting an injection composition from the injection gap into the material gap and the distribution recess to contact the material strand with the injection composition on the walls of the material gap and on the outside of the material strand guided along the wall surface, to obtain a modified material strand,iii) Closing the material gap in the modified material strand by joining the walls of the material gap contacted with the injection composition in a joining region spaced apart from the injector element along the extrusion direction E. The method according to the invention is used to produce strand-shaped vulcanizable rubber products, preferably tread components. However, the method according to the invention is not limited to treads, but is suitable for adding a conductive structure to all thick-walled extrudates with a certain thickness, for example, more than 2 mm, through which electrostatic charge can be reliably dissipated. Accordingly, an example of a method according to the invention is one in which the strand-shaped vulcanizable rubber product has an average thickness of 2 mm or more perpendicular to the extrusion direction E. A preferred method according to the invention iswherein the strand-shaped vulcanizable rubber product is a green tread or a partial ply of a green tread.

[0056] It can be considered a major advantage of the process according to the invention that it is very flexible with regard to the vulcanizable rubber mixture used. In light of the fact that the advantageous effects of the present invention are essentially attributable to design features of the extrusion template according to the invention and to the specific process control, it can be advantageously stated that the process according to the invention can be applied to essentially all typical vulcanizable rubber mixtures, in particular those used in the treads of vehicle tires, so that at this point, reference can be made in particular to the prior art known to the person skilled in the art.By way of example, a process according to the invention is provided in which the vulcanizable rubber mixture comprises one or more diene rubbers, and / or in which the vulcanizable rubber mixture comprises one or more electrically non-conductive fillers, and / or in which the vulcanizable rubber mixture comprises one or more additives selected from the group consisting of plasticizers, age inhibitors, and coupling agents. Due to the high relevance of the process according to the invention for equipping poorly conductive extrudates with a conductive CCB, in most cases it will be a process according to the invention in which the vulcanizable rubber mixture comprises less than 10 phr, preferably less than 5 phr, particularly preferably less than 3 phr, in particular less than 0.1 phr, of carbon black.

[0057] In light of the above explanations, the skilled person understands that the extrusion templates according to the invention and the method according to the invention are in principle not limited, even with regard to the injection composition used. The skilled person selects a suitable injection composition essentially against the background of their respective application requirements, the vulcanizable rubber mixtures used, the extrusion materials, and the other parameters of their specific process control, so that they are suitable for their purposes. Examples of usable injection compositions are disclosed, inter alia, in the prior art cited above. An example of this is a method according to the invention, wherein the injection composition is a dispersion comprising:

[0058] - at least one diene rubber, preferably polyisoprene,

[0059] - at least one electrically conductive filler, preferably carbon black, preferably in a combined mass fraction of 50 phr or more, preferably 70 phr or more, and

[0060] - a carrier liquid, preferably in a combined mass fraction of 450 phr or more, preferably 600 phr or more.

[0061] By way of example, a method according to the invention is additionally provided, wherein the injection composition additionally comprises: - at least one liquid diene polymer, preferably in a combined mass fraction of 50 phr or more, preferably of 70% or more, and / or

[0062] - a sulfur-based vulcanization system, preferably comprising at least one vulcanization accelerator, more preferably in a combined mass fraction of 2.5 phr or more, preferably 5 phr or more.

[0063] The term phr (parts per hundred parts of rubber by weight) is the quantity commonly used in the rubber industry for compound formulations. It indicates the mass fractions of the components in the rubber compound relative to the mass of the high-molecular-weight rubbers (weight-average molar mass Mw according to GPC greater than 60,000 g / mol) present in the rubber compound, whereby the combined mass fraction of the high-molecular-weight rubbers in the rubber compound corresponds to 100 phr. The weight-average molar mass is determined using gel permeation chromatography in accordance with DIN 55672-1: 2016-03 (GPC with tetrahydrofuran as eluent, polystyrene standard;

[0064] Size exclusion chromatography (SEC = size exclusion chromatography).

[0065] When selecting the injection composition, the inventors propose that those injection compositions whose viscosity is not too high can be processed particularly efficiently in the process according to the invention, so that they can flow particularly efficiently from the material gap into the distribution recess and contact the walls there. Accordingly, a process according to the invention is preferred, wherein the injection composition at 20 °C has a dynamic viscosity q measured according to DIN 53211:1987-06 of 30 Pa*s or less, preferably of 20 Pa*s or less, particularly preferably of 10 Pa*s or less. The injection compositions known from the prior art often rely on the use of a highly volatile solvent as the carrier fluid.This allows the solvent-dispersed components of the rubber composition contained in the injection composition to be applied to the walls of the material gap, where they remain as a coating after the solvent evaporates. However, the inventors of the present invention have found that, for both process-related and health reasons, as well as with regard to the quality of the resulting conductive webs, it is highly preferable to avoid the use of highly volatile solvents wherever possible. Instead, the inventors have developed a technology in which the carrier fluid is formed by a high-boiling component, namely, in particular, a mineral oil, and in particular, a paraffinic mineral oil.The corresponding injection composition is converted into a coating (at least not primarily) by evaporation of the solvent; rather, the mineral oil can be largely absorbed into the underlying vulcanizable rubber mixture, leaving a coating which, upon contact with the injection composition, forms a superficial layer which, in particular, has an increased carbon black content and consequently advantageous electrical conductivity. Accordingly, a process according to the invention is particularly preferred wherein the carrier liquid is a mineral oil, preferably a paraffinic mineral oil. Additionally or alternatively, a process according to the invention is also particularly preferred wherein the carrier liquid has a boiling point of 120°C or more, preferably of 140°C or more, particularly preferably of 160°C or more.

[0066] The invention further relates to a process for producing a vulcanized rubber product, comprising the process steps of the process according to the invention for producing a strand-shaped vulcanizable rubber product, as well as the step: iv) vulcanizing the strand-shaped vulcanizable rubber product or a rubber blank comprising the strand-shaped vulcanizable rubber product, preferably a vehicle tire blank, with vulcanization of the vulcanizable rubber mixture to obtain a vulcanized rubber product, preferably a vehicle tire.

[0067] Here, the strand-shaped vulcanizable rubber product is vulcanized, for example, according to the process customary in the tire industry, for example by sulfur-based crosslinking, for example at a temperature in the range of 130 to 200 °C, preferably in the range of 150 to 180 °C.

[0068] Finally, the invention also relates to a vulcanized rubber product, preferably produced or producible by the method according to the invention for producing a vulcanized rubber product, with a rubber element comprising a vulcanized rubber mixture, wherein the rubber element comprises on at least one surface a modification region extending along a covering direction B on the surface, wherein the rubber element comprises a modification layer connected to the modification region along the covering direction B and extending through the rubber element along a layer direction S, wherein the modification region and the modification layer comprise a vulcanized rubber material whose composition differs from the composition of the vulcanized rubber mixture,wherein the average width of the modification layer in the extension direction A perpendicular to the covering direction B and perpendicular to the layer direction S is 30 pm or less, wherein the average width of the modification layer in the extension direction A perpendicular to the covering direction B and perpendicular to the layer direction S is smaller than the average width of the modification region.

[0069] The vulcanized rubber product can, in principle, be any form of rubber product that involves the extrusion of a strand-like starting material in a preceding process step. The vulcanized rubber product according to the invention is vulcanized and accordingly no longer comprises vulcanizable rubber mixtures, but rather the corresponding rubber materials that can be produced therefrom. In this respect, the vulcanized rubber product comprises, in particular, a rubber element that comprises the specific conductive structure that can be produced using the method according to the invention. A corresponding rubber element can be, for example, the tread of a pneumatic vehicle tire.

[0070] A vulcanized rubber product according to the invention is preferred, wherein the vulcanized rubber product is a vehicle tire, preferably a pneumatic vehicle tire. A vulcanized rubber product according to the invention is preferred, wherein the rubber element is a tread or a partial layer of a tread, in particular a partial layer of a tread intended for road contact.

[0071] The arrangement of the conductive structure comprising the web, i.e. the modification layer and the conductive surface layers, i.e. the modification regions, in the rubber element is defined within the scope of the present invention primarily with regard to two directions, namely the covering direction B and the layer direction S. The rubber element comprises, on at least one surface, a modification region in which the composition differs from that of the rest of the vulcanized rubber mixture in the rubber element, which, as explained above, can be achieved by a coating or a modification of the previously vulcanizable rubber mixture in the process according to the invention. The person skilled in the art understands that the modification region is precisely the part that was produced in the extruded strand-shaped vulcanizable rubber product in the process according to the invention by the action of the distribution depressions of extrusion templates according to the invention.Accordingly, the covering direction B corresponds to the extrusion direction E at the time of production of the still unvulcanized rubber element.

[0072] As a result of the process described above, the modification area is bonded to a modification layer, i.e., the thin conductive CCB. This modification layer extends through the vulcanized rubber product and is firmly bonded to the surface modification area. Due to contact with the injection compound, the modification layer also has a different chemical composition than the surrounding vulcanized rubber mixture.

[0073] The direction along which the modification layer extends through the rubber element is referred to as the layer direction S. Using the example of a tread of a pneumatic vehicle tire, which encompasses the conductive structure approximately in the center of the tread, the covering direction B thus corresponds to the circumferential direction, while the layer direction S, for example, corresponds approximately to the radial direction.

[0074] The above definition of vulcanized rubber products according to the invention also expresses the relative dimensions of the modification layer and the modification region. These relationships would be defined in the direction perpendicular to the covering direction B and perpendicular to the layer direction S, which is referred to as the extension direction A. In a preferred embodiment of a substantially orthogonal configuration of the modification layer and modification region, this third direction corresponds to the third axis of a Cartesian coordinate system. Using the example of a tread on a vehicle tire, whose covering direction is the circumferential direction and whose layer direction is the radial direction, the extension direction A would correspond to the axial direction.

[0075] Preferred vulcanized rubber products according to the invention result from the above statements on preferred processes and extrusion templates.

[0076] For example, a vulcanized rubber product according to the invention is preferred, wherein the rubber element comprises on two opposite surfaces, preferably on the surface intended for road contact and the surface facing away from this surface, a modification region extending on the surface along a covering direction B, wherein the modification layer is connected to both modification regions.

[0077] Also preferred is a vulcanized rubber product according to the invention, wherein the modification layer extends completely through the rubber element along the layer direction S.

[0078] Also preferred is a vulcanized rubber product according to the invention, wherein the rubber element comprises two or more tread plies made of different vulcanized rubber mixtures, wherein the modification layer extends through all tread plies along the layer direction S. Also preferred is a vulcanized rubber product according to the invention, wherein the rubber element in the vulcanized rubber product is arranged with a surface on an electrically conductive layer, wherein the modification layer extends along the layer direction S from the surface intended for road contact to the electrically conductive layer, wherein the electrically conductive layer is preferably contacted by the modification region.

[0079] Likewise preferred is a vulcanized rubber product according to the invention, wherein the average width of the modification layer in the extension direction A is 20 pm or less, preferably 10 pm or less, particularly preferably 5 pm or less, and / or wherein the average width of the modification layer in the extension direction A is in the range from 0.5 to 20 pm, preferably in the range from 1 to 10 pm.

[0080] Furthermore, a vulcanized rubber product according to the invention is preferred, wherein the average width of the modification region in the extension direction A is 50 mm or less, preferably 10 mm or less, particularly preferably 5 mm or less, and / or wherein the average width of the modification region in the extension direction A is in the range from 1 to 40 mm, preferably in the range from 2 to 20 mm, particularly preferably in the range from 3 to 10 mm.

[0081] Also preferred is a vulcanized rubber product according to the invention, wherein the average width of the modification layer in the extension direction A is wider than the modification layer by a factor of 20 or more, preferably by a factor of 50 or more, particularly preferably by a factor of 100 or more, most particularly preferably by a factor of 200 or more.

[0082] Also preferred is a vulcanized

[0083] Rubber product, wherein the vulcanized rubber material has a higher electrical conductivity than the vulcanized rubber mixture, preferably by a factor of 10 or more, preferably by a factor of 100 or more, particularly preferably by a factor of 1000 or more.

[0084] Furthermore, a vulcanized rubber product according to the invention is preferred, wherein the vulcanized rubber mixture can be produced by vulcanizing a vulcanizable rubber mixture, and wherein the vulcanized rubber material can be produced by vulcanizing an injection composition comprising:

[0085] - at least one diene rubber, preferably polyisoprene,

[0086] - at least one electrically conductive filler, preferably carbon black, preferably in a combined mass fraction of 50 phr or more, preferably 70 phr or more, and

[0087] - a carrier liquid, preferably in a combined mass fraction of 450 phr or more, preferably 600 phr or more. or a mixed composition of the vulcanizable rubber mixture and the injection composition, which can be produced by contacting the vulcanizable rubber mixture with the injection composition.

[0088] The invention and preferred embodiments of the invention are explained and described in more detail below with reference to the accompanying figures.

[0089] Fig. 1 is a highly simplified schematic representation of material defects occurring in the prior art;

[0090] Fig. 2 is a schematic representation of an inventive

[0091] Extrusion template in a preferred embodiment; Fig. 3 is an enlarged view of the area around the injector element of the extrusion template according to the invention as shown in Fig. 2;

[0092] Fig. 4 is a schematic exploded view of a vulcanized rubber product according to the invention in a preferred embodiment; and

[0093] Fig. 5 is a schematic visualization of the conductive structure of the vulcanized rubber product according to Fig. 4.

[0094] Fig. 1 visualizes in a highly simplified representation which defects can occur in extruded material strands when the conductive web is made particularly thin. In Fig. 1a), the conductive web is covered by the flanking material strands after extrusion and does not extend to the surface of the corresponding rubber product intended for contact. In Fig. 1b), the end of the conductive web is covered by a material displacement, such as can occur after a tread blank is formed in the tire mold. In both cases in Fig. 1, the conductive web cannot ensure the necessary dissipation of an electrical charge.

[0095] Fig. 2 shows an extrusion template 10 according to the invention, sometimes also referred to as a spray bar, in a preferred embodiment. The extrusion direction E, the injector direction I, and the transverse direction Q are indicated in Fig. 2.

[0096] The extrusion template 10 according to the invention comprises a template body 12 and, within this template body 12, a template recess 16 enclosed by wall surfaces 14. An injector element 18 extends between the wall surfaces 14 through the template recess 16, which includes an injection gap 20. In the example shown in Fig. 2, the extrusion template 10 is designed as a preliminary template and has a steel template body 12 in which a template recess 16 with a trapezoidal cross-section is located. The injector element 18 extends through the template recess 16 between the wall surfaces 14 and is arranged precisely centrally in the example shown.

[0097] At the end of the injector element 18 located outside the extrusion template 10, a bore is indicated, through which the injector element 18 can be connected to a reservoir for the injection composition via fluid lines (not shown). The cylindrical injector element 18 is positioned substantially orthogonally on the wall surfaces 14, with the injection gap 20 extending substantially over the entire height of the template recess 16.The extrusion template 10 comprises in the wall surfaces 14 of the template recess 16, each in the contact area with the injector element 18, two similarly designed distribution recesses 22 (only one visible), which are provided so that during operation the injection composition from the injection gap 20 can also enter the distribution recess 22, so that an extruded material strand guided over it can also be contacted with the injection composition from the outer side running along the walls.

[0098] The injector element 18 of Fig. 2 is designed as a reversibly and non-destructively replaceable injector element 18 and can be removed along the injector direction I. An injector element 18 intended for replacement can then be guided through the template body 12 through the injector insertion opening thus formed until it engages in a complementary injector receiving recess on the opposite wall surface 14, wherein in the example shown, a part of the wall of the distribution recesses 22 is only formed by inserting the injector element 18 into the injector receiving recess. In other words, in the illustrated embodiment, the injector receiving recess and the injector insertion opening are each connected to the respective distribution recesses 22 in such a way that they only assume their final dimensions once an injector element 18 has been inserted.

[0099] Fig. 3 shows an enlarged section of the extrusion template 10 according to the invention as shown in Fig. 2, wherein in particular the details in the area of ​​the injector element 18 are shown enlarged. In Fig. 3, one of the two distribution recesses 22 can be seen particularly well. In the transverse direction Q, the distribution recess 22 is wider than the injection gap 20, whereby the conditions that are particularly relevant in practice are not shown in the schematic representation in Fig. 3. In practice, the injection gap 20 will in most cases be significantly smaller than indicated in Fig. 3 for reasons of clarity. For example, the injection gap 20 can have an average width of approximately 0.1 mm, whereas the distribution recess 22 has a width of, for example, 3 mm in the transverse direction Q in order to advantageously form wide contact surfaces in the rubber product that can be produced therewith. In Fig.3 it can be seen that the distribution recess 22 tapers along the extrusion direction E, so that a flattened distribution recess 22 is obtained, the depth of which decreases with increasing distance from the injector element 18 in order to have the least possible influence on the flow of the extruded material strand.

[0100] Fig. 4 now shows a schematic representation of a vulcanized rubber product 24, such as could be obtained with an extrusion template 10 according to Figs. 2 and 3, in an exploded view. For reasons of clarity, only one segment of a strand is shown, which may also extend significantly longer in the covering direction B. The schematically illustrated vulcanized rubber product 24 is a tread with a so-called "cap" and "base" construction.

[0101] The tread parts made of vulcanized rubber mixture arranged on both sides are separated from one another by an electrically conductive structure, which can be produced using the method according to the invention using an extrusion template 10 according to the invention. The exploded view serves to make this structure more visible. Fig. 4 shows a section of a tread, with the coverage direction B, along which the modification region 26a, 26b extends on the surface of the vulcanized rubber product 24, indicated. Also indicated is the layer direction S, along which the modification layer 28 extends through the "cap" and "base" layers of the vulcanized rubber product 24. Perpendicular to these two directions is the extension direction A, along which the width of the modification layer 28 and the two modification regions 26a, 26b can be determined.The vulcanized rubber product 24 comprises, with the modification layer 28, an advantageously thin CCB, for which, however, in contrast to the prior art, advantageous contacting is made possible by the large, yet again thin, modification regions 26a, 26b.

[0102] Finally, Fig. 5 shows a schematic enlarged view of the conductive structure of Fig. 4. In this it can be clearly seen that the two modification regions 26a, 26b along the

[0103] Extension direction A have a considerably larger average width than the modification layer 28. At the same time, however, it can also be seen that the thickness of the modification regions 26a, 26b along the layer direction does not differ significantly from the thickness of the modification layer 28. List of reference symbols

[0104] 10 Extrusion template

[0105] 12 stencil bodies

[0106] 14 Wall surfaces 16 Template recess

[0107] 18 Injector element

[0108] 20 Injection gap

[0109] 22 Distribution deepening

[0110] 24 Vulcanized rubber product 26a, b Modification area

[0111] 28 Modification layer

[0112] E Extrusion direction

[0113] I Injector direction Q Transverse direction

[0114] B Coverage direction

[0115] S layer direction

[0116] A Expansion direction

Claims

Claims 1. An extrusion template (10) for use in the extrusion of rubber products, comprising: a) a template body (12), b) a template recess (16) penetrating the template body (12) along an extrusion direction E and delimited by circumferential wall surfaces (14), and c) an elongate injector element (18) extending between the wall surfaces (14) along the injector direction I through the template recess (16), having an injection gap (20), wherein the extrusion template (10) is configured to create a material gap through the injector element (18) in a material strand extruded along the extrusion direction E through the template recesses (16) and to inject an injection composition into the material gap through the injection gap (20) in order to contact the extruded material strand with the injection composition at the walls of the material gap,wherein the extrusion template (10) comprises at least one distribution recess (22) in the wall surface (14) of the template recess (16), wherein the distribution recess (22) is wider than the injection gap (20) along the transverse direction Q perpendicular to the extrusion direction E and perpendicular to the injector direction I, and wherein the extrusion template (10) is designed such that an injection composition injected through the injection gap (20) into the material gap can enter the distribution recess (22), so that the extruded material strand guided over the distribution recess (22) is guided along the wall surface (14), outside of the material strand can be contacted with the injection composition present in the distribution recess (22).

2. Extrusion template (10) according to claim 1, wherein the distribution recess (22) is wider than the injection gap (20) by a factor of 5 or more transversely to the extrusion direction E and transversely to the injector direction I.

3. Extrusion template (10) according to one of claims 1 or 2, wherein the depth of the distribution recess (22) along the extrusion direction E decreases with increasing distance from the injector element (18).

4. Extrusion template (10) according to one of claims 1 to 3, wherein the side wall of the distribution recess (22) is partially formed by the injector element (18).

5. Extrusion template (10) according to one of claims 1 to 4, wherein the extrusion template (10) comprises at least one distribution recess (22) in the opposite wall surface (14) of the template recess (16) in the contact area with the injector element (18).

6. Extrusion template (10) according to one of claims 1 to 5, wherein the extrusion template (10) comprises an injector receiving recess and an injector insertion opening in the wall surfaces (14) of the template recess (16), wherein the injector element (18) extends through the injector insertion opening into the injector receiving recess, wherein the extrusion template (10) is designed so that the injector element (18) can be replaced reversibly and non-destructively.

7. Extrusion template (10) according to one of claims 1 to 6, wherein the extrusion template (10) comprises in the wall surfaces (14) of the template recess (16) two or more complementary injector insertion openings and injector receiving recesses for receiving an injector element (18) in different injector positions, wherein at least some of the injector positions are assigned at least one distribution recess (22), wherein the injector element (18) extends in an injector position through the corresponding injector insertion opening into the corresponding injector receiving recess, wherein the extrusion template (10) is designed so that the position of the injector element (18) can be changed reversibly and non-destructively between the injector positions.

8. Extrusion system comprising: aa) at least one extruder, and bb) at least one extrusion template (10) according to one of claims 1 to 7.

9. A process for producing a strand-shaped vulcanizable rubber product, with an extrusion system according to claim 8, comprising the process steps: i) extruding a material strand of at least one vulcanizable rubber mixture with an extruder through the extrusion template (10) along the extrusion direction E, wherein a material gap is created in the material strand by the injector element (18), ii) injecting an injection composition from the injection gap (20) into the material gap and the distribution recess (22) for contacting the material strand with the Injection composition on the walls of the material gap and on the outside of the material strand guided along the wall surface (14), to obtain a modified material strand, iii) closing the material gap in the modified material strand by joining the walls of the material gap contacted with the injection composition in a joining region spaced apart from the injector element (18) along the extrusion direction E.

10. The method according to claim 9, wherein the strand-shaped vulcanizable rubber product is a green tread or a partial ply of a green tread.

11. A method for producing a vulcanized rubber product (24), comprising the method steps of the method for producing a strand-shaped vulcanizable rubber product according to one of claims 1 to 10, and the step: iv) vulcanizing the strand-shaped vulcanizable rubber product or a rubber blank comprising the strand-shaped vulcanizable rubber product under vulcanization the vulcanizable rubber mixture to obtain a vulcanized rubber product (24).

12. A vulcanized rubber product (24) comprising a rubber element comprising a vulcanized rubber mixture, wherein the rubber element comprises, on at least one surface, a modification region (26a, 26b) extending along a covering direction B, wherein the rubber element comprises a modification layer (28) connected to the modification region (26a, 26b) along the covering direction B and extending through the rubber element along a layer direction S, wherein the modification region (26a, 26b) and the modification layer (28) comprise a vulcanized rubber material whose composition differs from the composition of the vulcanized rubber mixture, wherein the average width of the modification layer (28) in the extension direction A perpendicular to the covering direction B and perpendicular to the layer direction S is 30 μm or less,wherein the average width of the modification layer (28) in the extension direction A perpendicular to the covering direction B and perpendicular to the layer direction S is smaller than the average width of the modification region (26a, 26b)., 13. Vulcanized rubber product according to claim 12, wherein the rubber element is provided on two opposite surfaces, preferably on the surface intended for road contact and the surface Surface facing away from the surface, each comprising a modification region (26) extending on the surface along a covering direction B, wherein the modification layer (28) is connected to both modification regions (26a, 26b).

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