A friction mat and a method for producing a friction mat

Abstract

This invention relates to a friction mat (1) that comprises a first layer (2) of a polymeric material having a continuous structure with a first surface (3) and an opposite second surface (4), and a second layer (5) of a polymeric material having a granular structure. The second layer (5) extends from the second surface (4) and is partially embedded into the first layer (2), and the first surface (3) forms a first exterior surface of the friction mat (1).

Description

[0001]^ MAT BACKGROUND^OF^THE^INVENTION^ FIELD^OF^THE^INVENTION^ This invention relates to a friction mat and a method for producing a friction mat. DESCRIPTION^OF^PRIOR^ART In relation to anti-slip materials, such as materials used in safety- or anti-slip floorings, it is known to use different coatings and surface laminations in order to increase the surface friction and wear resistance of these materials. For example, different polymer-based materials, such as natural rubber, are known to be used as coating materials in these applications. Also different surface textures are known to be used for further increasing the surface friction. However, due to limitations set by the properties of the polymeric materials used in said safety applications, as well as by the available manufacturing methods, said polymeric materials typically need to be used in combination with a base layer providing a frame for the polymer to attach to. In more detail, said base layer is typically needed for providing a solid base for the polymer-based coating material during manufacturing, said polymer-based material typically being in a flowing form. Therefore, the base layer material may need to be provided even when it does not contribute optimally to the properties of the final product or may even influence them negatively. For example, different fabric materials may be used as base layer materials, wherein they may influence negatively the moisture resistance of the final product. SUMMARY^OF^THE^INVENTION An object of the present invention is to solve the above-mentioned drawback and to provide a friction mat that does not necessitate the use of a frame material for the polymeric structure. This object is achieved with a friction mat according to independent claim 1 and a method according to independent claim 7. By providing the friction mat with a first layer of a polymeric material having a continuous structure and a second layer of a polymeric material having a granular structure and being partially embedded into the first layer, it is possible to obtain a friction mat with a uniform base structure having a high level of mechanical strength and chemical resistance. Preferred embodiments of the invention are disclosed in the dependent claims. BRIEF^DESCRIPTION^OF^DRAWINGS In the following the present invention will be described in closer detail by way of example and with reference to the attached drawings, in which Figure 1 illustrates a first embodiment of a friction mat as seen in an oblique angle from above, Figure 2 illustrates the friction mat of Figure 1 as seen directly from the side, Figure 3 illustrates a second embodiment of the friction mat as seen directly from the side, Figure 4 illustrates a third embodiment of the friction mat as seen directly from the side, Figure 5 illustrates a fourth embodiment of the friction mat as seen directly from the side, Figure 6 illustrates a first embodiment of a method step for producing a friction mat, Figure 7 illustrates a second embodiment of the method step for producing a friction mat, Figure 8 illustrates an embodiment of another method step for producing a friction mat, Figure 9 illustrates an embodiment of another method step for producing a friction mat, Figure 10 illustrates an embodiment of another method step for producing a friction mat, and Figure 11 illustrates an embodiment of another method step for producing a friction mat. DESCRIPTION^OF^AT^LEAST^ONE^EMBODIMENT Figure 1 illustrates schematically a first embodiment of a friction mat 1. This example serves only to illustrate the main structural components of the friction mat 1, and their dimensions and exact positioning within the structure may deviate from said example in other embodiments of the friction mat. In the illustration of Figure 1, the friction mat is also illustrated as transparent so as to better illustrate its internal structure. The outer dimensions of the friction mat 1, namely its length and width along its plane of extension may be set freely based on the requirements set for any specific use case and are therefore not limited to the illustration of Figure 1. As seen in the example of Figure 1, the friction mat 1 comprises a first layer 2 of a polymeric material having a continuous structure. Said first layer 2 has a first surface 3 and an opposite second surface 4, wherein the first surface 3 forms a first exterior surface of the friction mat 1. In other words, said first surface 3 may be provided as, for example, a bottom surface of the friction mat 1 to be arranged into contact with an external surface to be covered with the friction mat, such as a floor surface or a surface of protective equipment. In the example of Figure 1, said first 3 and second surface 4 are parallel to each other and substantially planar, but in other embodiments, they may also comprise surface patterns, such as grip textures or other localized deviations from the planar form. As seen in the example of Figure 1, the friction mat 1 also comprises a second layer 5 of a polymeric material having a granular structure, wherein said second layer 5 extends from the second surface 4 of the first layer 2 and is partially embedded into the first layer 2. In other words, the second layer 5 is comprised of individual granules or grains 101 partially embedded into the first layer 2, such that the granules or grains 101 together define the second layer 5. In the example of Figure 1, each granule 101 has an irregular shape and a size deviating from the size of the other granules, but in other embodiments of the friction mat 1, their shape and size distribution may be controlled differently so as to deviate from the illustration of said example. The second layer 5 extends from the second surface 4 such that the part of each granule 101 not being embedded into the first layer 2 extends outwards from the second surface 4 to provide an irregular surface pattern. In Figure 1, the border at which each granule 101 extends from the second surface 4 is illustrated with a dashed line. To further illustrate the structure of the friction mat 1, Figure 2 illustrates schematically the friction mat of Figure 1 as seen directly from the side. In this example, the first surface 3 forming the first exterior surface of the friction mat 1 is provided as a continuous, uninterrupted surface such that the granules 101 of the second layer 5 do not extend from it. However, the granules 101 of the second layer 5 may also be arranged to contact the first surface 3 in other embodiments of the friction mat 1. In the examples of Figures 1 and 2, the second surface 4 of the first layer 2 and the second layer 5 extending from the second surface 4 form a second exterior surface of the friction mat 1. In other words, in this embodiment of the friction mat 1, the second exterior surface opposite the first exterior surface is formed as a combination of the surfaces of the granules 101 of the second layer 5 extending from the second surface 4 and the areas of the second surface 4 not covered by the granules 101. Thereby, said second exterior surface is formed as a textured surface providing high friction, wherein its surface roughness is predominantly determined by the size and morphology of the granules 101 of the second layer 5, as well as the distance between the adjacent granules 101 and the extent to which they extend from the second surface 4. Figure 3 illustrates schematically a second embodiment of the friction mat 1. The embodiment according to this example shares most of the characteristic features of the friction mat illustrated in Figures 1 and 2 and said second embodiment is therefore only discussed here in relation to the features specific to it. In the example of Figure 3, the friction mat 1 further comprises a third layer 6 of a polymeric material having a continuous structure with a third surface 7 facing away from the first surface 3 of the first layer 2. In other words, said third layer 6 is arranged such that the third surface 7 is provided as a surface opposite to the first surface 3. In said example, the second layer 5 of the polymeric material having a granular structure is arranged between the first layer 2 and the third layer 6 and is partially embedded into the first layer 2 and partially embedded into the third layer 6. In other words, the second granular layer 5 is located at the intersection between the first 2 and the third layer 6, and the granules 101 of the second layer 5 form a contact interface with both the first 2 and the third layer 6. Naturally, it is possible without deviating from the spirit of the invention that some of the individual granules 101 are entirely embedded into only either one of the first 2 and the third layer 6, thereby being provided as an outlier from the arrangement of the rest of the granules 101. In the example of Figure 3, the friction mat 1 also comprises a fourth layer 8 of a polymeric material having a granular structure, wherein said fourth layer 8 extends from the third surface 7 of the third layer 6 and is partially embedded into the third layer 6. In other words, said fourth layer 8 in the example of Figure 3 is arranged similar to the second layer 5 according to the example of Figures 1 and 2, wherein the fourth layer 8 is comprised of individual granules or grains 101 partially embedded into the third layer 6, such that the granules or grains 101 together define the fourth layer 8. In the example of Figure 3, each granule 101 has an irregular shape and a size deviating from the size of the other granules, but in other embodiments of the friction mat 1, their shape and size distribution may be controlled differently so as to deviate from the illustration of said example. The fourth layer 8 extends from the third surface 7 such that the part of each granule 101 not being embedded into the third layer 6 extends outwards from the third surface 7 to provide an irregular surface pattern. In the example of Figure 3, the third surface 7 and the fourth layer 8 extending from the third surface 7 form the second exterior surface of the friction mat 1. In other words, in this embodiment of the friction mat 1, the second exterior surface opposite the first exterior surface is formed as a combination of the surfaces of the granules 101 of the fourth layer 8 extending from the third surface 7 and the areas of the third surface 7 not covered by the granules 101. Thereby, said second exterior surface is formed as a textured surface providing high friction, wherein its surface roughness is predominantly determined by the size and morphology of the granules 101 of the fourth layer 8, as well as the distance between the adjacent granules 101 and the extent to which they extend from the third surface 6. With the arrangement of the layers of the friction mat 1 as described, a friction mat 1 having high mechanical strength and friction properties may be achieved. In said arrangement, the second granular layer 5 may be used as a basis for the third layer 6 to firmly adhere to, wherein the highly textured interface provided by the granules 101 of the second layer enables a strong adherence between the layers. Simultaneously, the second layer 5 may also provide additional mechanical strength and bulk to the structure and may also contribute to the properties of the second exterior surface formed by the third surface 7 and the fourth layer 8 extending from the third surface 7. The size of the granules 101 of the second layer 5 may deviate from the size of the granules 101 of the fourth layer 8, as may be seen in the example of Figure 3 wherein the granules 101 of the second layer 5 have an average grain size smaller than that of the granules 101 of the fourth layer 8. Figure 4, on the other hand, illustrates schematically a third embodiment of the friction mat 1 wherein the granules 101 of the second layer 5 have an average grain size larger than that of the granules 101 of the fourth layer 8. More precisely, the fourth layer 8 according to this embodiment comprises granules 101 having a relatively small average grain size and forming a uniform, gapless cover on the third layer 6. Thereby, in said example the second exterior surface of the friction mat 1 is formed entirely of the fourth layer 8 extending from the third surface 7. With the arrangement as described, a uniform surface structure having a relatively low level of roughness may be provided. The average grain size of the second layer 5 and the fourth layer 8 may be in the range of, for example, 1 mm to 10 mm. In the examples of Figures 1 to 3, the first layer 2 and the second layer 5 are comprised of the same polymeric material, said polymeric material being a polyvinyl chloride (PVC) based material. Further, in the example of Figure 3 comprising also the third 6 and the fourth layer 8, these layers are also comprised of the same polyvinyl chloride (PVC) based material. With said arrangement, chemical compatibility between adjacent layers may be ensured, as well as favorable mechanical and chemical properties of the friction mat 1. However, in other embodiments of the friction mat 1, the material of each of said layers may also be chosen differently from the material of the other layers based on, for example, specific requirements set for each use case. For example, in applications where high toughness and surface wear resistance are required simultaneously, the material of the first layer 2 may be chosen to provide maximized toughness to the friction mat 1, and the material of the second 5 or the fourth layer 8 may be chosen to be particularly wear resistant. In some embodiments, only part of the material of one or each of said layers may also be varied based on specific use requirements. For example, pine oil -based components may be used for replacing a part of fossil-based components of the PVC -based material used in the layers of the friction mat. The friction mat 1 according to the examples of Figures 1 and 2 may be produced by a method comprising the following steps: - (A) taking into use a mold surface 9. Said mold surface 9 may be provided by, for example, taking into use a sheet 12 comprising the mold surface 9 as schematically illustrated in the example of Figure 6 illustrating a method step according to a first embodiment of said method, wherein the mold surface 9 is a planar surface of the sheet 12. The sheet 9 may be, for example, a flat metallic sheet, and two mold surfaces 9 may be provided simultaneously to the opposite sides of the sheet 12. As illustrated in the example of Figure 6, several sheets 12 may also be provided simultaneously to provide a larger number of the mold surfaces 9. The sheets 12 may be fastened to a movable stand so as to facilitate moving of the friction mat 1 to be formed during and between the subsequent processing steps. In the example of Figure 7, on the other hand, schematically illustrating a method step according to a second embodiment of the method, the mold surface 9 is provided by taking into use a cylinder 14 comprising the mold surface 9. In other words, the mold surface 9 in this example comprises the cylindrical outer surface of the cylinder 14. Said cylinder 14 may be, for example, a metallic barrel arranged rotatably to a movable stand, so as to provide means for adjusting the position of the mold surface 9 and to facilitate moving of the friction mat 1 to be formed during and between the subsequent processing steps. - (B) Providing a first layer 2 of a polymeric material having a flowing form on the mold surface 9. In the method step according to the example of Figure 6, for example, said providing a first layer 2 comprises immersing the sheet 12 comprising the mold surface 9 into a reservoir 13 of the polymeric material, wherein the polymeric material is in a flowing form. Preferably, the sheet 12 at this step is arranged into a vertical position, so as to ensure an even layer of the flowing polymeric material being provided over the area of the mold surface 9 and excess material flowing off from the surface after removing the sheet 12 from the reservoir 13. Said immersing of the sheet 12 may be accomplished by, for example, lowering the sheet 12 along a vertical trajectory by means of the movable stand. After removing the sheet 12 from the reservoir 13, it may be held stationary above the reservoir 13 for a predefined time so as to allow any excess material still remaining to flow off from the mold surface 9, before proceeding to the following method step. In the method step according to the example of Figure 7, on the other hand, the providing a first layer 2 on the mold surface 9 comprises applying a flow 15 of the polymeric material having a flowing form on the mold surface 9. In said example, the flow 15 of the polymeric material is provided from a reservoir 102 of the polymeric material arranged above the cylinder 14 comprising the mold surface 9, such that the flow 15 is gravitationally applied on the mold surface 9. During said step, the cylinder 14 may be rotated around its middle axis 103 so as to ensure an even layer of the flowing polymeric material being provided over the surface area of the mold surface 9, and the flow 15 may also be moved in relation to the cylinder 14. - (C) Partially embedding a second layer 5 of a polymeric material having a granular structure into the first layer 2 of the polymeric material having a flowing form. This step may be implemented by, for example, placing the sheet 12 or the cylinder 14 comprising the mold surface 9 inside a rotatable container together with the polymeric material having a granular structure, said rotatable container then being rotated or shaked so as to apply a feed 16 of the polymeric material having the granular structure into contact with the first layer 2. If necessary, before the step as described, the mold surface 9 may be spinned by, for example, rapidly rotating the sheet 12 or the cylinder 14 comprising the mold surface 9 so as to remove any excess polymeric material in a flowing form still remaining on the mold surface 9. The angle position of the mold surface 9 may also be gradually adjusted so as to control the thickness of the first layer 2 being formed. Another means of implementing said method step is schematically illustrated in Figure 8, wherein the partially embedding the granular second layer 5 into the first layer 2 is also performed by applying a feed 16 of the polymeric material having a granular structure on the first layer 2. More precisely, in said example the feed 16 of the granular material is applied on the first layer 2 gravitationally from above, wherein the first layer 2 is provided on the mold surface 9 of the cylinder 14. With said arrangement, the cylinder 14 may be rotated around its middle axis 103 with a controlled speed so as to gradually expose the whole circumference of the cylinder 14 to the feed 16 of the granular material, and the feed 16 may also be moved along the longitudinal axis of the cylinder 14 to gradually expose the whole length of the cylinder 14 to the feed. Alternatively, the feed 16 may be provided with a width to cover the length of the cylinder 14. Said partial embedding of the granular second layer 5 into the first layer 2 then takes place through the granules 101 of the second layer 5 penetrating the unsolidified first surface of the first layer 2 and becoming partly enclosed within the flowing polymeric material of the first layer 2. - (D) Heating the first layer 2 and the second layer 5 to solidify the first layer 2. Said heating may be implemented by, for example, transferring the first 2 and the second layer 5 with the mold surface 9 to a heat treatment chamber, wherein the first layer 2 having a flowing form is then solidified by applying an appropriate heat treatment as a result of gasification and evaporation of elements comprised in the flowing polymeric material. Said heat treatment may comprise heating of the first layer 2 and the second layer 5 to a temperature in the range of, for example, 100 °C to 200 °C, wherein the exact temperature and duration of treatment may be determined based on, for example, the type of polymeric material used for the first layer 2. Based on the chosen temperature and the duration of the heat treatment, also different interface structures may be obtained for the interface between the first 2 and the second layer 5. - (E) Separating the first layer 2 from the mold surface 9. Said separating may be done by either manually or by means of automated machinery applying a force to the first layer 2 so as to detach it from the mold surface 9. In the embodiments where the mold surface 9 is provided to the cylinder 14 and the first layer 2 is thereby formed into a form of a seamless tube, the separating may be preceded by a step of providing a cut to the first 2 and the second layer 5 so as to obtain a rectangular shape to the friction mat 1 after separating it from the mold surface 9. The friction mat 1 according to the examples of Figures 3 and 4 may be produced by said method by further providing the following steps preceding the separating the first layer 2 from the mold surface 9: - (D2) Providing a third layer 6 of a polymeric material having a flowing form on the second layer 5. In the method step according to the example of Figure 9, for example, said providing a third layer 6 comprises again immersing the sheet 12 comprising the mold surface 9 into the reservoir 13 of the polymeric material, wherein the polymeric material is in a flowing form. Said reservoir 13 may be the same or a different reservoir as described above in relation to the method step (B). Preferably, the sheet 12 at this step is again arranged into a vertical position, so as to ensure an even layer of the flowing polymeric material being provided over the area of the second layer 5 and excess material flowing off from the surface. Said immersing of the sheet 12 may be accomplished by, for example, lowering the sheet 12 along a vertical trajectory by means of the movable stand. After the immersing, the sheet 12 may be held stationary above the reservoir 13 for a predefined time so as to allow any excess material still remaining to flow off from the mold surface 9, before proceeding to the following method step. It may also be slowly rotated along a vertical plane so as to ensure the layer to be formed to have an even thickness across its surface area. In the method step according to the schematic illustration of Figure 10, on the other hand, the providing a third layer 6 on the second layer 5 comprises applying the flow 15 of the polymeric material having a flowing form on the second layer 5. In said example, the flow 15 of the polymeric material is again provided from the reservoir 102 of the polymeric material arranged above the cylinder 14 comprising the mold surface 9, such that the flow 15 is gravitationally applied on the second layer 5. Said reservoir 102 may be the same or a different reservoir as described above in relation to the method step (B). During said step, the cylinder 14 may be rotated so as to ensure an even layer of the flowing polymeric material being provided over the surface area of the second layer 5, and the flow 15 may also be moved in relation to the cylinder 14. - (D3) Partially embedding a fourth layer 8 of a polymeric material having a granular structure into the third layer 6 of the polymeric material having a flowing form. This step may be implemented by, for example, placing the sheet 12 or the cylinder 14 comprising the mold surface 9 again inside the rotatable container together with the polymeric material having a granular structure, said rotatable container then being rotated or shaked so as to bring the granules into contact with the third layer 6. If necessary, before the step as described, the mold surface 9 may be spinned by, for example, rapidly rotating the sheet 12 or the cylinder 14 comprising the mold surface 9 so as to remove any excess polymeric material in a flowing form still remaining in the third layer 6. The angle position of the mold surface 9 may also be gradually adjusted so as to control the thickness of the third layer 6 being formed. In the schematic illustration of Figure 11, the partially embedding the granular fourth layer 8 into the third layer 6 is performed by applying the feed 16 of the polymeric material having a granular structure on the third layer 6. In said example, the feed 16 of the granular material is applied on the third layer 6 gravitationally from above, wherein the third layer 6 is provided on the cylinder 14. With said arrangement, the cylinder 14 may be rotated with a controlled speed so as to gradually expose the whole circumference of the cylinder 14 to the feed 16 of the granular material, and the feed 16 may also be moved along the longitudinal axis of the cylinder 14 to gradually expose the whole length of the cylinder 14 to the feed. Alternatively, the feed 16 may be provided with a width to cover the length of the cylinder 14. Said partial embedding of the granular fourth layer 8 into the third layer 6 then takes place through the granules 101 of the fourth layer 8 penetrating the unsolidified third surface of the third layer 6 and becoming partly enclosed within the flowing polymeric material of the third layer 6. - (D4) Heating the third layer 6 and the fourth layer 8 to solidify the third layer 6. Said heating may be implemented by, for example, transferring the first 2, the second 5, the third 6 and the fourth layer 8 with the mold surface 9 to the heat treatment chamber, wherein the third layer 6 having a flowing form is then solidified by applying an appropriate heat treatment as a result of gasification and evaporation of elements comprised in the flowing polymeric material. Said heat treatment may comprise heating of the layers to a temperature in the range of, for example, 100 °C to 200 °C, wherein the exact temperature and duration of treatment may be determined based on, for example, the type of polymeric material used for the third layer 6. Based on the chosen temperature and the duration of the heat treatment, also different interface structures may be obtained for the interface between the layers. Figure 5 illustrates schematically a fourth embodiment of the friction mat 1, in which the first layer 2 comprises a first base layer 10 and second base layer 11 merged together. The structure of the first layer 2 as described may be provided through the method steps of: - (B1) Providing the first base layer 10 of a polymeric material having a flowing form on the mold surface 9, - (B2) heating the first base layer 10 to solidify the first base layer 10, and - (B3) providing a second base layer 11 of a polymeric material having a flowing form on the first base layer 10. All said steps (B1) to (B3) may be performed correspondingly to the steps described above in relation to the method steps (B) and (D), such that the providing the first 10 and the second base layer 11 may be performed correspondingly to the providing the first 2 and the third layer 6, and the heating the first base layer 10 may be performed correspondingly to the heating the first layer 2 and the second layer 5. As an outcome of said method steps (B1) to (B3), a multi-layered structure may be obtained for the first layer 2. The method steps as described may be used for, for example, adjusting the thickness of the first layer 2 by providing additional base layers as needed for any specific use application of the friction mat 1. The thickness of an individual base layer 10, 11 may be, for example, approximately 1mm, and the first layer 2 may be arranged to have a thickness of any multiple of the thickness of an individual base layer 10, 11. It is to be understood that the above description and the accompanying figures are only intended to illustrate the present invention. It will be obvious to a person skilled in the art that the invention can be varied and modified without departing from the scope of the invention.

Claims

CLAIMS:

1. A friction mat (1), c h a r a c t e r i z e d ^ in that the friction mat (1) comprises: a first layer (2) of a polymeric material having a continuous structure with a first surface (3) and an opposite second surface (4), and a second layer (5) of a polymeric material having a granular structure, wherein the second layer (5) extends from the second surface (4) and is partially embedded into the first layer (2), and the first surface (3) forms a first exterior surface of the friction mat (1).

2. A friction mat (1) according to claim 1, c h a r a c t e r i z e d ^ in that at least one of the second surface (4) and the second layer (5) extending from the second surface (4) form a second exterior surface of the friction mat (1).

3. A friction mat (1) according to claim 1, c h a r a c t e r i z e d ^ in that the friction mat (1) further comprises: a third layer (6) of a polymeric material having a continuous structure with a third surface (7) facing away from the first surface (3), and a fourth layer (8) of a polymeric material having a granular structure, wherein the second layer (5) of the polymeric material having a granular structure is arranged between the first layer (2) and the third layer (6) and is partially embedded into the first layer (2) and partially embedded into the third layer (6), the fourth layer (8) extends from the third surface (7) and is partially embedded into the third layer (6), and at least one of the third surface (7) and the fourth layer (8) extending from the third surface (7) form a second exterior surface of the friction mat (1).

4. A friction mat (1) according to claim 3, c h a r a c t e r i z e d ^ in that the second layer (5) of a polymeric material having a granular structure and the fourth layer (8) of a polymeric material having a granular structure have a different average grain size.

5. A friction mat (1) according to any one of the claims 1 to 4, c h a r a c t e r i z e d ^ in that the first layer (2) and the second layer (5) comprise the same polymeric material, whereinthe polymeric material is a polyvinyl chloride (PVC) based material.

6. A friction mat (1) according to claim 3 or 4, c h a r a c t e r i z e d ^ in that the first layer (2), the second layer (5), the third layer (6) and the fourth layer (8) comprise the same polymeric material, wherein the polymeric material is a polyvinyl chloride (PVC) based material.

7. A method for producing a friction mat (1), c h a r a c t e r i z e d ^ in that the method comprises: - (A) taking into use a mold surface (9), - (B) providing a first layer (2) of a polymeric material having a flowing form on the mold surface (9), - (C) partially embedding a second layer (5) of a polymeric material having a granular structure into the first layer (2) of the polymeric material having a flowing form, - (D) heating the first layer (2) and the second layer (5) to solidify the first layer (2), and - (E) separating the first layer (2) from the mold surface (9).

8. A method according to claim 7, c h a r a c t e r i z e d ^ in that before the (E) separating the first layer (2) from the mold surface (9) the method further comprises: - (D2) providing a third layer (6) of a polymeric material having a flowing form on the second layer (5), - (D3) partially embedding a fourth layer (8) of a polymeric material having a granular structure into the third layer (6) of the polymeric material having a flowing form, and - (D4) heating the third layer (6) and the fourth layer (8) to solidify the third layer (6).

9. A method according to claim 7 or 8, c h a r a c t e r i z e d ^ in that the (B) providing a first layer (2) of a polymeric material having a flowing form on the mold surface (9) comprises: - (B1) providing a first base layer (10) of a polymeric material having a flowing form on the mold surface (9), - (B2) heating the first base layer (10) to solidify the first base layer (10), and - (B3) providing a second base layer (11) of a polymeric material having a flowing form on the first base layer (10).

10. A method according to any one of the claims 7 to 9, c h a r a c t e r i z e d ^ in that the (A) taking into use a mold surface (9) comprises taking into use a sheet (12) comprising the mold surface (9), and the (B) providing a first layer (2) of a polymeric material having a flowing form on the mold surface (9) comprises immersing the sheet (12) comprising the mold surface (9) into a reservoir (13) of the polymeric material having a flowing form.

11. A method according to any one of the claims 7 to 9, c h a r a c t e r i z e d ^ in that the (A) taking into use a mold surface (9) comprises taking into use a cylinder (14) comprising the mold surface (9), and the (B) providing a first layer (2) of a polymeric material having a flowing form on the mold surface (9) comprises applying a flow (15) of the polymeric material having a flowing form on the mold surface (9).

12. A method according to any one of the claims 7 to 10, c h a r a c t e r i z e d ^ in that the (C) partially embedding a second layer (5) of a polymeric material having a granular structure into the first layer (2) of the polymeric material having a flowing form comprises applying a feed (16) of the polymeric material having a granular structure on the first layer (2).

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