WO2023116989A1

WO2023116989A1 - Shoe sole material, outsole and method for producing the shoe sole material or the outsole

Info

Publication number: WO2023116989A1
Application number: PCT/DE2022/200296
Authority: WO
Inventors: Zoheil Sharifi; Konstantin Efimov
Original assignee: Continental Reifen Deutschland Gmbh
Priority date: 2021-12-21
Filing date: 2022-12-12
Publication date: 2023-06-29
Also published as: DE102021214842A1

Abstract

The invention relates to a shoe sole material comprising at least one rubber mixture, characterised in that the rubber mixture has a substantially closed porous structure, and to an outsole having a shoe sole material of this kind. The invention also relates to a method for producing a shoe sole material, comprising at least the following steps: a. mixing at least one rubber mixture with at least one blowing agent or with microcapsules; and b. heating the mixture to a temperature of at least 100°C at a pressure of at least 7 bar. The invention further relates to the use of a shoe sole material of this kind for producing a shoe.

Description

Shoe sole material, outsole and method of manufacturing the shoe sole material or outsole

The invention relates to a shoe sole material according to the preamble of patent claim 1 and an outsole with such a shoe sole material according to the preamble of patent claim 7. The invention also relates to a method for producing the shoe sole material or the outsole according to the preamble of patent claim 9.

Different materials for shoe soles are known in the prior art. For example, shoe soles can be made of rubber, cork, PVC or leather. Depending on the material, the different materials lead to different properties and qualities. The rubber sole has brought a special advance in the field of sports shoes. Modern sports shoes now have a special cushioning system in the rubber sole that stabilizes the foot, cushions movements and actively supports runners. In the field of work shoes, rubber soles with their very strong profile ensure an absolutely safe step and also protect against acids and oil. Hiking and trekking shoes also rely on heavily profiled soles made of rubber or rubber-like materials.

Shoe soles with a rubber mixture are known, for example, from WO 2010050628A2, which describes an outsole using a foamed rubber mixture for shoe soles.

Although rubber is considered a very high-quality sole material, it also has some disadvantages. For example, rubber soles have an increased weight, which can be uncomfortable for the user.

This is where the present invention comes in. It is the object of the invention to provide a shoe sole material made from at least one rubber mixture which has improved properties. In addition, the object of the invention is to provide an outsole made from at least one rubber mixture which exhibits improved properties. Furthermore, the object of the invention is to provide a method for producing the shoe sole material or the outsole, by means of which improved properties of the shoe sole material or the outsole are achieved.

The object of the invention is achieved by a shoe sole material with the features of patent claim 1 and by an outsole with such a shoe sole material with the features of patent claim 7. Furthermore, the object of the invention is achieved by a method for producing the shoe sole material or the outsole with the features of Patent claim 9 solved.

The object of the invention is achieved by a shoe sole material comprising at least one rubber mixture, the rubber mixture having an essentially closed porous structure.

Such a shoe sole material according to the invention has improved slip resistance and thus improved comfort due to its essentially closed porous structure. Furthermore, the shoe sole material has a lower weight since material can be saved, so that the overall production costs are also reduced.

For the purposes of the invention, the porosity represents the ratio of the cavity volume to the total volume of the rubber mixture. A closed porous structure is essential to the invention, a structure in which the cavities are not connected to one another or to the environment. For the purposes of the invention, an essentially closed porous structure means that the proportion of closed pores is greater than the proportion of open pores, it being possible for there to be no open pores. An exclusively closed porous material can also have isolated open pores, with the proportion of open pores preferably being less than 1%, particularly preferably less than 0.5%, very particularly preferably less than 0.1%. In a preferred embodiment, the shoe sole material is rubber, consisting of at least one rubber mixture. Different rubber mixtures are conceivable for use. Usual tire rubber mixtures can be used. At least one rubber mixture preferably comprises at least one component selected from the group consisting of S-SBR, NR, BR, silica and mineral oils, in particular naphthenic and/or paraffinic oils.

In one embodiment of the invention, the pores are distributed essentially homogeneously. For the purposes of the invention, an essentially homogeneous distribution of the pores means that the pores are arranged regularly. Such regularity means that the beneficial properties of slip resistance are ensured throughout the material. In an additional or alternative embodiment, the pores are substantially homogeneous in size. A homogeneous size distribution is particularly advantageous since the safety of a shoe is improved with such a shoe sole material.

In a further embodiment of the invention, the pore size is in the range from 1 to 40%. Such a porosity is advantageous since the cushioning properties for such a shoe sole material are improved and the comfort for the user is perceived as more pleasant. A preferred range is from 1.5 to 35%.

In a further embodiment of the invention, the pore diameter of the closed pores is in the range from 10 to 100 μm, in particular in the range from 20 to 80 μm. Such a pore diameter has also turned out to be advantageous with regard to the stability of such a material. Such an advantage goes hand in hand with improved properties in terms of surefootedness and damping properties. It has also been found that heat transfer is improved with such a pore diameter. In a further embodiment of the invention, the shoe sole material has no porous structure on the surface or a structure with a lower porosity compared to the interior of the material which is enclosed by the surface. It is conceivable that the surface is smooth and the interior has a porous structure. The surface layer can have a thickness in the range of 0.1 to 0.5 mm, for example.

In a further embodiment of the invention, the porous structure has an air content in the range from 0.1 to 40%. In a preferred embodiment, the surface of the shoe sole material has a lower proportion of air than the interior. Such an air content is advantageous because the shoe sole material has improved cushioning properties and better slip resistance. In a preferred embodiment, the proportion of air can range from 0.1 to 27%.

The object of the invention is also achieved by an outsole for a shoe, having a shoe sole material as described.

It is advantageous that such an outsole according to the invention shows a significantly better comfort than other outsoles. The outsole according to the invention is characterized in that it comprises at least one rubber mixture and the outsole has an essentially porous area, the porous area comprising essentially closed pores. Advantageously, the outsole according to the invention is therefore also significantly more stable and non-slip.

In a preferred embodiment, the outsole consists of rubber with at least one rubber mixture, the outsole having an essentially porous area and an essentially non-porous layer arranged on the surface. It is essential that the entire outsole is made of the same material. This gives the outsole a special stability. In the context of the invention, the outsole is the tread of a shoe, ie the lower part of the bottom of the shoe, which is in direct contact with the ground. An outsole is also referred to as a shoe sole or outsole.

The embodiments and advantages described in relation to the shoe sole material also apply, vice versa, to the outsole according to the invention.

In one embodiment, the outsole has a thickness ranging from 5 to 40 mm.

In a further embodiment of the invention, the outsole has a layer on the surface which is essentially non-porous or less porous than on the inside, the layer preferably having a thickness of at least 0.5 mm, preferably a thickness in the range of 0. 5 to 1.5 mm. Preferably, the substantially porous interior portion has a thickness in the range of 4.5 to 39.5 mm. In the context of the invention, the layer described is the layer that is in contact with the ground. If this layer is not porous, the proportion of non-porous rubber is greater than 99.5%, preferably greater than 99.9%, for the purposes of the invention.

In a further embodiment of the invention, the outsole has a profile on the surface. Such a profile improves the properties of the outsole in terms of walking stability and comfort.

The object is also achieved by a method for producing a shoe sole material, in particular a described shoe sole material, the method comprising at least the following steps: a. Mixing at least one rubber mixture with at least one blowing agent and/or with microcapsules and b. Heating the mixture to a temperature of at least 100 °C at a pressure of at least 7 bar. It has been shown according to the invention that the interaction between the temperature and the pressure leads to an improved structure in the shoe sole material. The improved structure is essentially distinguished by the fact that the structure has essentially closed pores which, in particular, are more homogeneously distributed. It is essential to the invention that the at least one blowing agent leads to a porous structure in the mixture as a result of the heating process. It is thus advantageous that the method according to the invention produces a shoe sole material which has less weight due to the improved pore structure. Furthermore, the slip resistance is significantly better, which increases the overall comfort for the user. Additionally or alternatively, it has been shown that the use of microcapsules is advantageous with regard to the formation of the pores. With microcapsules, the porous structure is essentially created by mechanical interactions, so that the production of shoe sole materials is improved in terms of costs.

The explanations and advantages in relation to the shoe sole material and the outsole also relate, vice versa, to the method according to the invention.

Different rubber mixtures are conceivable for the use of the method according to the invention. Usual tire rubber mixtures can be used. At least one rubber mixture preferably comprises at least one component selected from the group consisting of S-SBR, NR, BR, silica and mineral oils, in particular naphthenic and/or paraffinic oils.

In one embodiment of the invention, the heating takes place for at least 8 minutes. The total heating time of at least 8 minutes is necessary because the pores have to form. Advantageously, it is only after such a time that uniform pores can form, which, among other things, lead to improved slip resistance of the material. In a further embodiment of the invention, the heating takes place in stages, with each stage preferably being held for at least 1.5 minutes. At least two stages are preferred, and two to five stages are particularly advantageous, since the pores form more uniformly as a result of the staged heating. This leads to improved porosity in the shoe sole material.

In another embodiment of the invention, the blowing agent comprises oxybisbenzenesulfonyl hydrazide (OBSH). It has proven to be advantageous that at least one blowing agent from this group leads to a uniform porous structure, as a result of which the density of the material is reduced overall and the weight is reduced.

Bloating agents are pore-forming greenhouse gases and are understood within the meaning of the invention as agents which split off gases (for example N2 or CO2) under the influence of heat.

Furthermore, microcapsules are understood to mean temperature-resistant spherical bodies. Glass spheres are examples, although other bodies can also be used. Such microcapsules preferably have a size in the range from XX to YY.

In a further embodiment of the invention, the mixture is heated to a temperature of at least 140° C., preferably at least 160° C., and/or the heating takes place at a pressure of at least 12 bar, preferably at least 16 bar. It is advantageous that such a relationship between temperature and pressure leads to better formation of the closed pores.

In a further embodiment of the invention, the heating is followed by a step c, in which the mixture is subjected to a cooling process and then to a molding process. In the molding process, the material obtained is adapted to an outsole shape.

Furthermore, the object is achieved by a porous shoe sole material made of at least one rubber mixture, which can be obtained by the described procedure is. Such a porous shoe sole material has an improved porous system.

Furthermore, the invention relates to the use of a described shoe sole material and/or a described outsole and/or a porous shoe material, which can be obtained by the described method, for the production of a shoe.

Further advantages and features of the shoe sole material according to the invention, the outsole according to the invention and the method result from the dependent claims, which relate to advantageous configurations of the present invention and as such are not to be understood as limiting. The invention also includes combinations of the features of different subclaims, even if the subclaims do not relate to one another or if they belong to different claim categories. Furthermore, combinations of preferred and particularly preferred embodiments can also be combined with one another. This also applies to the individual features of the exemplary embodiment discussed below, insofar as these are not recognizable to the person skilled in the art as necessarily belonging to one another.

character description

Further details and advantages of the present invention result from the following description of the exemplary embodiment in conjunction with the drawing. In this shows

FIG. 1 shows a schematic layer structure of an embodiment of the outsole according to the invention.

FIG. 1 shows a schematic layer structure of a shoe sole with an outsole 1 according to the invention, which is arranged on a base 2 . The ground 2 can be understood as a section of the shoe sole. Alternatively, the shoe sole can be arranged on the substrate 2, with the shoe sole at least the outsole 1 comprises. The surface of the outsole 1 is the ground contact area 3. The surface layer 4 extends along the entire surface of the outsole 1 and has no porosity. The porous layer 5 is arranged between the surface layer 4 and the substrate 2 . According to the invention, the porous layer 5 comprises a closed porous structure 6 and consists of rubber.

Table 1 below shows results from two examples E1 and E2 according to the invention, the heating process taking place either in 2 stages or in β stages. The pore diameter is an average.

Table 1

For the purposes of the invention, the porosity was determined via the increase in volume of the rubber mixture. To do this, the volume of the rubber mixture was determined before it was mixed with a blowing agent and compared with the volume after the heating process.

Reference list:

1 outsole

2 underground

3 ground contact area

4 surface layer

5 porous layer

6 Section of closed pores

Claims

patent claims

1. Shoe sole material comprising at least one rubber mixture, characterized in that the rubber mixture has a substantially closed porous structure (6).

2. Shoe sole material according to claim 1, characterized in that the pores (6) are distributed essentially homogeneously and/or have an essentially homogeneous size.

3. Shoe sole material according to claim 1 or 2, characterized in that the porosity is in the range from 1 to 40%, preferably in the range from 1.5 to 35%.

4. Shoe sole material according to one of claims 1 to 3, characterized in that the pore diameter of the closed pores is in the range from 10 to 100 μm, in particular in the range from 20 to 80 μm.

5. Shoe sole material according to one of claims 1 to 4, characterized in that the shoe sole material has no porous structure on its surface or a structure with a lower porosity than on the inside.

6. Shoe sole material according to one of claims 1 to 5, characterized in that the porous structure (6) has an air content in the range from 0.1 to 40% and in particular the surface of the shoe sole material has a lower air content than the interior.

7. Outsole (1) for a shoe, comprising a shoe sole material according to one of claims 1 to 6.

8. Outsole (1) according to claim 7, characterized in that the outsole has a layer (4) on the surface which is essentially non-porous or less porous than on the inside, the layer (4) preferably having a thickness of at least 0.5 mm, preferably a thickness in the range from 0.5 to 1.5 mm.

9. Method for producing a shoe sole material, in particular a shoe sole material according to one of claims 1 to 6, characterized by at least the following steps: a. Mixing at least one rubber mixture with at least one blowing agent or with microcapsules and b. Heating the mixture to a temperature of at least 100 °C at a pressure of at least 7 bar.

10. The method according to claim 9, characterized in that the heating takes place for at least 8 minutes.

11. The method according to claim 9 or 10, characterized in that the heating takes place in stages, each stage preferably being maintained for at least 1.5 minutes.

12. The method according to any one of claims 9 to 11, characterized in that the blowing agent comprises oxybisbenzenesulfonyl hydrazide (OBSH).

13. The method according to any one of claims 9 to 12, characterized in that the mixture is heated to a temperature of at least 140 °C, preferably at least 160 °C and/or the pressure is at least 12 bar, preferably at least 16 bar.

14. Porous shoe sole material made from at least one rubber mixture, obtainable by a method according to any one of claims 9 to 13.

15. Use of a shoe sole material according to one of claims 1 to 6 or the outsole (1) according to one of claims 7 or 8 or a porous shoe material according to claim 14 for producing a shoe.