Foamed shoe component

Abstract

The present disclosure relates to a method for producing a shoe sole (1) which comprises a foamed component (2). The method comprises at least the following method steps of: Providing a first part (3) made from a polymeric material; Arranging at least one insert (4) at least partially on a first outer surface (31) of the first part (3); Forming a semi-finished part (5) by attaching a second part (6) on the first outer surface (31) of the first part (3) and thereby enclosing the insert (4), whereby the second part (6) is bonded on the first outer surface (31) of the first part (3) except for the area (A) covered by the insert (4); Foaming of the semi-finished part (5) by initiating a foaming of the first part (3) and / or the second part (6) and thereby creating a pocket (7) by outgassing of blowing agent, whereby the pocket (7) is located between the separated first part (3) and the second part (6) and the insert (4) remains within the pocket (7). The present disclosure further relates to a shoe sole (1) comprising a foamed component (2).

Description

[0001] Foamed shoe component

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to a method for producing a shoe sole and the shoe sole as such.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] US2023397694A1 published on 14.12.2023 on behalf of Nike Inc. relates to a method of manufacturing a cushioning element for an article of footwear. The method comprises the steps of impregnating a molten first thermoplastic composition with a blowing agent comprising a supercritical fluid. The first thermoplastic composition comprises a first thermoplastic copolyester elastomer. A bladder is inserted into a mold cavity, wherein a second thermoplastic composition defines at least a portion of an exterior surface of the bladder. The impregnated molten first thermoplastic composition is injected into the mold cavity which contains the bladder. Physically foaming the bladder in the mold cavity, whereby the injected molten first thermoplastic composition is expanded into a first foam, whereby the supercritical fluid nucleates foam cells in the molten first thermoplastic composition. The molten first thermoplastic composition has a foaming temperature during the physically foaming. During the physically foaming the second thermoplastic composition contacts at least a portion of the exterior surface of the bladder with the molten first thermoplastic composition. While being in the mold cavity, the first foam is solidified and forms bonds between the first thermoplastic com- position and the second thermoplastic composition, whereby the second thermoplastic composition and the molten first thermoplastic composition came into contact during the physically foaming step. The solidified and bonded first foam and bladder are removed from the mold cavity and the cushioning element is formed, whereby the first foam of the cushioning element is a physically-foamed thermoplastic multicellular foam.

[0006] SUMMARY OF THE DISCLOSURE

[0007] Cushioning and energy return are important performance parameters of footwear, especially for athletic footwear. Many different approaches have been developed to optimize cushioning and energy return. Some of the known approaches focus on energy return plates, such as plates with a specific geometry or shape, or made of a specific material, which balances stability, rigidity and elasticity. These energy return plates are attached to or embedded in the sole assembly. Other approaches focus on the sole more broadly, using, for example, gel cores or air cushions in the heel area of the shoe to increase the cushioning of the shoe and thus reduce the strain on the wearer's musculoskeletal system. Another strategy explored in the prior art focuses on sole designs that include vertically arranged spring elements, typically in the heel area of the sole. When walking, the sole typically makes initial contact with the ground in the heel area. These vertical spring elements are then compressed under the influence of the wearer's weight and are released when the foot pushes off the ground.

[0008] Known sole assemblies typically extend in a longitudinal direction from a heel area across a midfoot area to a forefoot area of the sole assembly. These sole assemblies comprise a midsole extending in a vertical direction from an upper surface configured to face an upper to a lower surface configured to face an outsole. Besides the already mentioned energy return plates, gel cores, air cushions or spring elements, there are also sole assemblies known from the prior art which comprise a bladder made from a first thermoplastic material, which is enclosed by a second thermoplastic composition. In case that such a bladder is enclosed in a shoe sole, these bladders are typically encompassed by the foamed midsole. One of the disadvantages of this solution is that the bladder has to be made in a first process, before it can be embedded in the actual sole in a subsequent process, typically the foaming step of the midsole. Another disadvantage is that in case of recycling, the bladder, which is typically made from a polymer which is different from the actual sole, has to be removed from the sole which is complex and expensive.

[0009] One objective of the present disclosure can therefore be seen in providing an improved sole component. For example, a shoe comprising an improved sole component could be provided, to provide local cushioning and energy return and to overcome at least some of the disadvantages of the prior art.

[0010] The present disclosure relates to a method for producing a shoe sole comprising a foamed component. The method comprises at least the following method steps:

[0011] • Providing a first part made from a polymeric material;

[0012] Arranging at least one insert at least partially on a first outer surface of the first part; • Forming a semi-finished part by attaching a second part on the first outer surface of the first part and thereby enclosing the insert, whereby the second part is bonded on the first outer surface of the first part, except for the area covered by the insert;

[0013] • Foaming of the semi-finished part by initiating a foaming of the first part and / or the second part and thereby creating a pocket by outgassing of blowing agent, whereby the pocket is located between the separated first part and the second part and the insert remains within the pocket.

[0014] The pocket is a three-dimensional structure formed by a deliberately formed gas accumulation. The pocket’s layout and cross-section are defined by the shape of the insert. The insert may have a thickness, which may vary between a thickness of 0.05 mm, being e.g. in the form of a thin paper, up to a thickness of 2mm, being e.g. a cardboard. The insert is typically quasi two-dimensional which is to be understood that the height being negligible small compared to the extensions in the width and length directions. For achieving the desired cushioning effect and energy return, the pocket preferably has a volume of at least 225 mm3, more preferably of at least 500 mm3. The pocket may have a round or oval cross-section. The pocket may have a diameter or a longest longitudinal extension of at least 10 mm, with the diameter or longest longitudinal extension preferably being between 10 mm and 100 mm, more preferably being between 15 mm and 60 mm, most preferably between 20 mm and 40 mm. The volume of the pocket is preferably between 500 mm3and 65’000 mm3, more preferable between 1 ’500 mm3and 35’000 mm3. The pocket can cover an area of the first part and / or the second part of at least 50 mm2to 1900 mm2, more preferable between 150 mm2to 1300 mm2. The pocket may have an aspect ratio in the range of 1 to 5, more preferable between 1 and 2.5. The aspect ratio is to be understood as the ratio of the maximum dimension from the center point of the pocket to a wall of the pocket in relation to the minimum dimension from the center point of the pocket to the wall of the pocket.

[0015] The wall of the pocket is formed by the surface of the first part respectively the surface of the second part facing the pocket and thereby defining the shape and delimiting the volume of the pocket. For pockets with regular shapes such as a sphere, the aspect ratio is defined by length / width, with the distances being measured from the center point of the pocket. For pockets with irregular shapes, the aspect ratio can be defined as the ratio of the maximum distance from the center of mass of the equivalent solid of the shape to the surface of the shape (Lmax ) relative to the minimum distance from the same point to the surface (Lmin).

[0016] The first part and / or the second part can be made by injection molding and the second part is preferably molded on the first outer surface of the first part. Depending on the foaming method to be used, the first part and / or the second part can be already loaded with a blowing agent before the injection step or may be later on loaded after the injection step, for example in an autoclave. In a preferred variation, both the first and the second part are each loaded with a blowing agent. Alternatively, also only the first part or the second part may be loaded with a blowing agent and therefore only one of the two parts may be foamed. The first part made from a polymeric material may be injection molded in a first injection molding step in a first mold, before the at least one insert is arranged at least partially on the first outer surface of the first part. The first part may be placed in a second mold and after arranging the at least one insert, the second part may be arranged on the first outer surface of the first part by injection molding in a second injection molding step. Thereby, the insert is enclosed and the semi-finished part is formed. Preferably the second part is molded onto the first outer surface of the first part and materially bonded, except for the area of the at least one insert. This creates a material bond between the first part and the second part before the foaming step. The insert can therefore act as a separating element, which locally separates the first part from the second part.

[0017] The first part may comprise a cavity in the first outer surface in which the insert can be placed, prior to attaching the second part on the first outer surface of the first part. This cavity acts as an undercut such that after arranging the at least one insert, the first outer surface surrounding the at least one insert merges with the surface of the at least one insert without an elevation.

[0018] Alternatively or in addition to injection molding, the first part and / or the second part may be bonded to each other at the first outer surface of the first part made from a polymeric material by heat pressing. This allows for an accurate and gas tight connection of the first and the second part over the full surface, except for the area where the at least one insert is placed. By heat pressing the first part and / or the second part may be at least locally softened or molten and thereby materially bonded with each other. The insert can be in the form of a coating or in the form of a separating strip, preferably in the form of a paper strip, especially preferred in the form of a wax coated paper strip. It has been observed that the material choice of the insert also has an impact on the properties of the pocket. Surprisingly it has been observed, that with similar process parameters and a similar layout and size of the at least one insert, the pocket of a wax coated paper strip is larger in volume than the pocket of an uncoated paper stip. Therefore, the size of the pocket can be influenced by the process parameters, being it the amount of blowing agent, as well as temperature and pressure during foaming, as well as the material selection and size of the at least one insert.

[0019] The insert fulfills two main functions. First, the insert defines the cross-section of the pocket in the foamed component. While a circular insert leads to a pocket with a spherical shape, an oval insert leads to a pocket with a non-spherical shape, such as an ovoid pocket. The desired cushioning and damping properties of the foamed component can be strongly impacted by the size, location and layout of the at least one insert. Second, the insert causes the creation of the pocket. The outgassing of the blowing agent is caused due to the change in pressure and / or temperature. The gas thereby diffuses to the surfaces of the foamed component, being the outer surfaces of the first and / or second part as well as the surfaces of the first and second part which face the at least one insert. The blowing agent which diffuses towards the at least one insert thereby cannot escape and is trapped in the area of the at least one insert. The accumulation of outgassing blowing agent thereby causes the separation of the first and second part in the area of the at least one insert and thereby the pocket is formed.

[0020] The foaming of the foamed component can be done with a physical blowing agent, preferably in the form of an inert gas or a mix of inert gasses. Hereby physical blowing agents are used in the manufacture of foams. The physical blowing agents may be compressed gases and volatile liquids such as N2, CO2, hydrocarbons, ketones and alcohols. N2, air, CO2 or a mixture of air and helium are examples of gaseous blowing agents. Among these N2 and air are preferred since they are inert, non-toxic, non-flammable and have a low diffusivity with respect to the majority of polymers. In comparison to N2 as a blowing agent in the polymer foaming process, CO2 has the advantage that it also affects polymer properties and can enhance polymer processability. However, both N2 and CO2 are considered to be sustainable alternatives.

[0021] The foaming of the semi-finished part may be done in an autoclave, The semifinished part is typically placed in the autoclave and the first part and / or the second part are loaded with a blowing agent before the actual foaming under pressure elevated above atmospheric pressure. The foaming of the loaded semi-finished part is initiated by reducing the pressure and / or increasing the temperature in the autoclave. Thereby the outgassing of the blowing agent is initiated which leads to the foaming and the creation of the pocket. After loading the semi-finished part with the inert gas under pressure the inert gas is released typically under reduced pressure and thereby forms pores in the polymeric material. The advantage of using physical blowing agent is that the physical foaming method has relatively low costs, especially carbon dioxide and nitrogen have low costs, is flame-retardant and non-polluting, so the application is environmental friendly compared to chemical foaming. The physical blowing agent additionally has no residue in the foamed part after foaming. It has furthermore little effect on the properties of the foamed polymeric material. The first part and / or the second part may be extruded and / or injection molded out of materials like TPU, EVA, TPEE, PE, Pebax. After placing the insert and assembling the semi-finished part, the semi-finished part is typically placed in an autoclave and therein impregnated with typically carbon dioxide or nitrogen, or a mixture of the two. Then the pressure is released to a pressure level to foam to obtain a foamable material. The blowing agent can be in a supercritical state. The semi-finished part is placed in the autoclave and supercritical fluid is injected(ni- trogen or carbon dioxide or mixed gas), raise the temperature and pressure, and keep the temperature and pressure for a certain period of time according to the process conditions , and then quickly exhaust and release the pressure, the supercritical physical foaming material will be foamed. Typical process parameters are a pressure of 16MPa, with a duration of about 3 hours and a temperature of 130 C .

[0022] The foaming of the semi-finished part may alternatively be done with a chemical blowing agent. The foaming of the semi-finished part may be done under heat influence. First the first part and the second part are provided, with at least one of them comprising a chemical blowing agent. The foaming of the semi-finished part may be initiated by increasing the temperature and thereby initiating the chemical reaction, which causes outgassing of the blowing agent for creating the pocket. Chemical blowing agents are generally solid organic components or minerals, which decompose in a certain temperature range. Similar to the physical blowing, also the chemical foaming method generates a gas to foam the polymeric material. Heating of the chemical blowing agent added to the plastic causes the chemical blowing agent to decompose and release the gas to foam the poly- meric material. It is also possible to utilize a chemical interaction between components of the polymeric material. The process of injection molding of a foamed polymeric material using a chemical blowing agent is basically the same as that of a general injection molding process. The polymer granules already contain the chemical foaming agent or it is added in the plasticizing unit. In short, no matter which kind of polymeric raw material is selected, no matter which kind of foaming method is adopted, the foaming process generally has to pass through the stages of forming nuclei, forming of the pocket and foam solidification.

[0023] After the foaming process, the first part and / or the second part may be additionally bonded to each other at the first outer surface of the first part made from a polymeric material by heat pressing with a stencil mold. The additional heat pressing step can increase the bonding between the first part and the second part on the first outer surface. In addition, the heat pressing with a heated stencil mold can be used to weld the upper surfaces of the finished foamed component, to smoothen the surface and close pores. This can increase the gas tightness of the foamed component and prevent the gas trapped in the pocket from diffusing. The stencil mold can have at least one recess which is large enough to encircle the pocket. The objective is to compress the foamed material surrounding the pocket. The mold typically comprises an upper mold part and a lower mold part, whereby one of the two mold parts has the recess. The foamed component is typically clamped between the upper mold part and the lower mold part.

[0024] A subsequent method step with the stencil mold can be carried out after the foaming of the semi-finished part. The stencil mold can be heated or be at room temperature. The stencil mold can comprise at least one recess, which encircles the pocket. The at least one recess can be formed as a slot in the upper and / or lower mold part or as a blind hole, e.g with a spherical geometry. The stencil mold can either selectively or essentially fully come in contact with the surface of the foamed component. After the foaming process, the pressing step with the stencil mold can increase the bonding between the first part and the second part on the first outer surface. In addition, in case of heat pressing with a heated stencil mold, the upper surfaces of the finished foamed component can be molten, to smoothen the surface and close pores. This can increase the gas tightness of the foamed component and prevent the gas trapped in the pocket from diffusing.

[0025] By compressing the foamed component, the mechanical properties are influenced. By compressing the foamed component, the density and therefore hardness of the foamed component can be increased. Consequently, the damping and rebound properties can be tuned. Good results can be achieved when the foamed component is compressed by up to 50%, preferably between 20% and 50%. The stencil mold can be used to partially compress the foamed component with different intensity. The region around the pocket, which is within the at least one recess of the stencil mold is typically compressed less, than the regions of the foamed component which are in direct contact with the stencil mold.

[0026] The present disclosure further relates to a shoe sole, which comprises a foamed component. The foamed component comprises a first part made from a polymeric material and at least one insert, which is arranged at least partially on a first outer surface of the first part. A second part is arranged on the first outer surface of the first part and thereby encloses the insert, whereby the second part is bonded on the first outer surface of the first part, except for the area covered by the insert. A pocket, preferably with a volume of at least 225 mm3, more preferably with at least 500 mm3, is located between the separated first part and the second part, with the insert being arranged within the pocket. The foamed component can be either made integral with the shoe sole or made in a first step and then integrated in the sole. The foamed component typically forms part of the midsole of a sports- or running shoe. In case that the foamed component is made integral with the shoe sole, the first part is typically a first half of a sole and the second part a second half of the sole. Depending on the desired mechanical properties of the sole, a number of inserts with different layouts can be arranged on the first outer surface of the first part.

[0027] For achieving the desired cushioning effect and energy return, the pocket preferably has a round or oval cross-section. The pocket may have a diameter or a longest longitudinal extension of at least 10 mm, with the diameter or longest longitudinal extension preferably being between 10 mm and 100 mm, more preferably being between 15 mm and 60 mm, most preferably between 20 mm and 40 mm.. In case of a spherical shape of the pocket, the volume of the pocket is preferably between 500 mm3and 65’000 mm3, more preferable between 1 ’500 mm3and 35’000 mm3. The pocket can cover an area of the first part and / or the second part of at least 50 mm2to 1900 mm2, more preferable between 150 mm2to 1300 mm2. The pocket may have an aspect ratio in the range of 1 to 5, more preferable between 1 and 2.5. The aspect ratio is to be understood as the ratio of the maximum dimension from the center point of the pocket to the wall of the pocket in relation to the minimum dimension from the center point of the pocket to the wall of the pocket. The first part and the second part may be material bonded to each other at the first outer surface of the first part except for the area of the first outer surface on which the insert is placed. After the foamed component is foamed and the midsole is finished, typically on a first outer surfaces of the midsole an outsole is arranged while on a second outer surfaces of the midsole an upper of a shoe is arranged. The insert may be in the form of a coating or in the form of a separating strip, preferably a separating strip in the form of a paper strip, more preferably in the form of a wax coated paper strip. In case of a sole, the insert remains within the pocket in the finished shoe. The insert typically has a layout out of the group of the following: round, circular, elliptical, rectangular, and squared. Depending on the desired mechanical properties, a number of inserts can be arranged. The number of inserts arranged between the first part and the second part can cover up to 75 % of the area of the first outer surface of the first part, preferably up to 50%, more preferably up to 25%.

[0028] It is to be understood that both the foregoing general description and the following detailed description present embodiments, and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments, and together with the description serve to explain the principles and operation of the concepts disclosed. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings which should not be considered limiting to the disclosure described in the appended claims. The drawings are showing:

[0030] Fig. 1 a perspective view onto a first schematic embodiment of the foamed component;

[0031] Fig. 2 a sectional lateral view of the foamed component according to Figure 1 ; Fig. 3 the method step of providing a first part of the foamed component according to Figure 1 with a cavity for receiving an insert;

[0032] Fig. 4 the method step of inserting an insert into the cavity of the first part of the foamed component according to Figure 3;

[0033] Fig. 5 the method step of attaching a second part to the first part of the foamed component according to Figure 4 with thereon arranged insert;

[0034] Fig. 6 in Fig. 6a a perspective view onto the foamed component according to Figure 1 before foaming and in Fig. 6b a sectional lateral view thereof;

[0035] Fig. 7 a perspective view onto a second schematic embodiment of the foamed component; Fig. 8 a sectional lateral view of the foamed component according to Figure

[0036] Fig. 9 a perspective view onto the first schematic embodiment of the foamed component with a first stencil mold; Fig. 10 a sectional lateral view of the foamed component according to Figure 9 with the first stencil mold;

[0037] Fig. 11 a photograph of a first embodiment of the first part;

[0038] Fig. 12 a photograph of a first embodiment of the first part with arranged inserts; Fig. 13 a photograph of a first embodiment of the semi-finished part;

[0039] Fig. 14 a photograph of a first embodiment of the foamed component;

[0040] Fig. 15 a schematic illustration of an embodiment of a foamed component with a second stencil mold;

[0041] Fig. 16 a schematic illustration of an embodiment of a foamed component with a third stencil mold;

[0042] Fig. 17 a schematic illustration of the embodiment of the foamed component according to Fig. 16 before and after processing with the stencil mold. DESCRIPTION OF THE EMBODIMENTS

[0043] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

[0044] Figures 1 and 2 show a first schematic embodiment of the foamed component 2. In Fig. 1 as a perspective view and in Fig. 2 as a sectional lateral view. The shown foamed component 2 forms part of a midsole. The shown foamed component 2 comprises a first part 3 made from a polymeric material and an insert 4, which is arranged inside the pocket 7 between the first part 3 and the second part 6. In the shown idealized schematic illustration, the insert 4 is arranged centrally in the pocket 7. As can be obtained from Figure 14, in the foamed state the insert 4 is in reality arranged in a non-oriented manner within the pocket 7.

[0045] As can be obtained from the sectional view in Figure 2, the shown second part 6 is arranged on the first outer surface 31 of the first part 3 and thereby encloses the insert 4. The second part 6 is bonded on the first outer surface 31 of the first part 3 except for the area covered by the insert 4. In the shown embodiment, the foamed component 2 is made in an integral manner with the shoe sole. In the shown embodiment, the pocket 7 has a spherical shape with a diameter between 15mm to 40mm. The first part 3 and the second part 6 are material bonded to each other at the first outer surface 31 of the first part 3 except for the area of the first outer surface 31 in which the insert 4 is placed.

[0046] Figures 3 to 6 show the method steps for producing the semi-finished part 5. The first part 3 and the second part 6 are each made by injection molding and the second part 6 is molded on the first outer surface 31 of the first part 3, as can be also obtained from Figure 13. In the shown foaming method, the first part 3 and the second part 6 are not loaded with a blowing agent before the injection step, but are in a later step loaded in an autoclave. Thereby, both the first and the second part 6 are loaded with a blowing agent. Alternatively, also only the first part 3 or the second part 6 may be loaded with a blowing agent and therefore only one of the two parts may be foamed as shown by Figures 7 and 8. The first part 3 is made from a polymeric material and injection molded in a first injection molding step in a first mold as shown by Figure 3, before the at least one insert 4 is arranged at least partially on the first outer surface 31 of the first part 3 as shown by Figure 4.

[0047] The shown first part 3 comprises a cavity 32 in the first outer surface 31 in which the insert 4 is placed, prior to attaching the second part 6 on the first outer surface 31 of the first part 3. Alternatively or in addition to injection molding the second part 6 onto the outer surface of the first part 3, the first part 3 and / or the second part 6 may be bonded to each other at the first outer surface 31 of the first part 3 made from a polymeric material by heat pressing. After arranging the at least one insert 4, the second part 6 is molded on the first outer surface 31 of the first part 3 by injection molding in a second injection molding step as shown by Figure 5. Thereby the insert 4 is enclosed and the semi-finished part 5 is formed, which is shown by Figures 6a and 6b. This allows for an accurate connection of the first and the second part 6 over the full surface, except for the area A where the at least one insert 4 is placed. The shown insert 4 is in the form of a coating or in the form of a separating strip, preferably in the form of a separating strip in the form of a paper strip, especially preferred a wax coated paper strip.

[0048] Figures 7 and 8 show a second schematic embodiment of the foamed component 2. In Fig. 7 as a perspective view and in Fig. 8 as a sectional lateral view. The first part 3 and / or the second part 6 may be extruded and / or injection molded out of materials like TPU, EVA, TPEE, PE, PEBAX. After placing the insert 4 and assembling the semi-finished part 5, the shown semi-finished part 5 is placed in an autoclave and therein impregnated with typically carbon dioxide or nitrogen, or a mixture of the two. Then the pressure is released to a pressure level to foam to obtain a foamable material. The blowing agent can be in a supercritical state. The semi-finished part 5 is placed in the autoclave and supercritical fluid is in- jected(nitrogen or carbon dioxide or mixed gas), raise the temperature and pressure, and keep the temperature and pressure for a certain period of time according to the process conditions , and then quickly exhaust and release the pressure, the supercritical physical foaming material will be foamed. Typical process parameters are a pressure of 16MPa, with a duration of about 3 hours and at a temperature of 130 C . In the embodiment of Figures 7 and 8 only the second part is foamed.

[0049] Figures 9 and 10 show the first schematic embodiment of the foamed component 2 according to Fig. 1 with a first stencil mold 8, comprising an upper and lower mold half. After the foaming process, the first part 3 and / or the second part 6 may be additionally bonded to each other at the first outer surface 31 of the first part 3 made from a polymeric material by heat pressing with a stencil mold 8. The additional heat pressing step can increase the bonding between the first part 3 and the second part 6 on the first outer surface 31 . In addition, the heat pressing with a heated stencil mold 8 can be used to weld the upper surfaces of the finished foamed component 2, to smoothen the surface and close pores. This can increase the gas tightness of the foamed component 2 and prevent the gas trapped in the pocket 7 from diffusing. The stencil mold 8 can have at least one recess 81 which is large enough to encircle the pocket 7. The objective is to compress the foamed material surrounding the pocket 7.

[0050] Figures 11 to 13 show the method steps for making the semi-finished part 5. The method for producing a foamed component 2 comprises at least the following method steps. A first part 3 is provided which is made from a polymeric material as shown by Figure 11. The shown first part 3 comprises a cavity 32 in the first outer surface 31 in which the insert 4 is placed, prior to attaching the second part 6 on the first outer surface 31 of the first part 3. Alternatively or in addition to injection molding the second part 6 onto the outer surface of the first part 3, the first part 3 and / or the second part 6 may be bonded to each other at the first outer surface 31 of the first part 3 made from a polymeric material, by heat pressing. After arranging the at least one insert 4, the second part 6 is molded on the first outer surface 31 of the first part 3 by injection molding in a second injection molding step as shown by Figure 13. Thereby the insert 4 is enclosed and the semifinished part 5 is formed, which is shown by Figure 12. This allows for an accurate connection of the first and the second part 6 over the full surface, except for the area where the at least one insert 4 is placed. The shown insert 4 is in the form of a coating or in the form of a separating strip, preferably in the form of a separating strip in the form of a paper strip, especially preferred a wax coated paper strip.

[0051] Figure 14 shows a photograph of a first embodiment of the foamed component 2. The shown insert 4 is in the form of a separating strip, preferably a separating strip in the form of a paper strip and more preferably in the form of a wax coated paper strip. In case of a sole, the insert 4 remains within the pocket 7 in the finished shoe. The shown insert 4 is in the form of a separating strip 41 , preferably a separating strip 41 in the form of a paper strip more preferably in the form of a wax coated paper strip. The shown separating strip 41 has a layout out of the group of the following: round, circular, elliptical, rectangular, and squared. Other insert layouts could also be used, depending on the desired cross-section of the pocket. Depending on the desired mechanical properties, a number of inserts 4 can be arranged. The number of inserts 4 arranged between the first part 3 and the second part 6 can cover up to 75 % of the area of the first outer surface 31 of the first part 3, preferably up to 50%, more preferably up to 25%. The foaming of the semi-finished part 5 may alternatively be done with a chemical blowing agent. The foaming of the semi-finished part 5 may be done under heat influence. First the first part 3 and the second part 6 are provided, with at least one of them comprising a blowing agent. The foaming of the semi-finished part 5 is initiated by increasing the temperature and thereby initiating the foaming, which causes the foaming of the semi-finished part 5 and outgassing of the blowing agent for creating the pocket 7. Figures 15 and 16 each show a schematic illustration of an embodiment of a foamed component 2 with a stencil mold 8. The second stencil mold 8 as shown by Figure 15, comprises an upper and lower mold half, with the upper mold half comprising recesses 81 , which each encircle a pocket 7. The third stencil mold 8 as shown by Figure 16 also comprises an upper and lower mold half, with the upper mold half comprising recesses 81 , which each encircle a pocket 7 and in addition come in contact with essentially the entire surface of the foamed component 2. After the foaming process, the heat pressing step by the respective stencil mold 8 increases the bonding between the first part 3 and the second part 6 on the first outer surface 31 . In addition, the heat pressing with a heated stencil mold 8 is used to soften or melt the upper surfaces of the finished foamed component 2, to smoothen the surface and close pores. This increases the gas tightness of the foamed component 2 and prevent the gas trapped in the pocket 7 from diffusing.

[0052] Figure 17 shows the embodiment of the foamed component 2 according to Figure 16 before (dotted lines) and after processing (solid lines) with the stencil mold 8. By compressing the foamed component 2, the mechanical properties are influenced. By compressing the foamed component 2, the density and therefore hardness of the foamed component 2 is increased. Consequently, the damping and rebound properties are tuned. The foamed component 2 is compressed between 20% and 50%. The stencil mold is used to partially compress the foamed component with different intensity. The regions around the pockets, which are within the respective recesses of the stencil mold are typically compressed less, than the regions of the foamed component which are in direct contact with the stencil mold. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the Spirit and scope of the disclosure.

[0053] LIST OF DESIGNATIONS

[0054] 1 Shoe sole 10 5 Semi-finished part

[0055] 2 Foamed component 6 Second part

[0056] 3 First part 7 Pocket 31 First outer surface (first 71 Wall (pocket) part) 8 Stencil mold

[0057] 32 Cavity (first part) 15 81 Recess (stencil mold)

[0058] 4 Insert V Volume (pocket)

[0059] 41 Separating strip (insert) A Area (first part)

Claims

PATENT CLAIMS1 . Method for producing a shoe sole (1 ) comprising a foamed component (2), the method comprising at least the following method steps: a. Providing a first part (3) made from a polymeric material; b. Arranging at least one insert (4) at least partially on a first outer surface (31 ) of the first part (3); c. Forming a semi-finished part (5) by attaching a second part (6) on the first outer surface (31 ) of the first part (3) and thereby enclosing the insert (4), whereby the second part (6) is bonded to the first outer surface (31 ) of the first part (3) except for the area (A) covered by the insert (4); d. Foaming of the semi-finished part (5) by initiating the foaming of the first part (3) and / or the second part (6) and thereby creating a pocket (7) by outgassing of blowing agent, whereby the pocket (7) is located between the separated first part (3) and the second part (6) and the insert (4) remains within the pocket (7).

2. Method according to claim 1 , wherein the pocket (7) has a volume (V) of at least 225 mm3, more preferably of at least 500 mm3.

3. Method according to at least one of claims 1 or 2, wherein the pocket (7) covers an area (A) of the first part (3) and / or the second part (6) of 50 mm2to 1900 mm2, more preferable between 150 mm2to 1300 mm2and / or has an aspect ratio in the range of 1 to 5, more preferable between 1 and 2.5.

4. Method according to at least one of claims 1 to 3, wherein the foaming is done with a physical blowing agent, preferably in the form of an inert gas or a mix of inert gasses, or alternatively in the form of a chemical blowing agent.

5. Method according to at least one of claims 1 to 4, wherein the foaming of the semi-finished part (5) is done in an autoclave, by: a. Placing the semi-finished part (5) in an autoclave and loading the first part (3) and / or the second part (6) with a blowing agent before the foaming; b. Initiating the foaming of the semi-finished part (5) by reducing the pressure and / or increasing the temperature in the autoclave and thereby initiating the outgassing of the blowing agent to create the pocket (7); c. Removing the foamed component (2) from the autoclave.

6. Method according to at least one of claims 1 to 4, wherein the foaming of the semi-finished part (5) is done under heat influence, by: a. Providing the first part (3) and the second part (6) with at least one of them comprising a chemical blowing agent;b. Initiating the foaming of the semi-finished part (5) by increasing the temperature and thereby initiating the chemical reaction which causes outgassing of the blowing agent () for creating the pocket(7).

7. Method according to at least one of the preceding claims, wherein the first part (3) comprises a cavity (32) in the first outer surface (31 ) in which the insert (4) is placed prior to attaching the second part (6) on the first outer surface (31 ) of the first part (3).

8. Method according to at least one of the preceding claims, wherein the first part (3) and / or the second part (6) are made by injection molding and the second part (6) is preferably molded on the first outer surface (31 ) of the first part (3).

9. Method according to at least one of the preceding claims, wherein the first part (3) and / or the second part (6) are bonded to each other at the first outer surface (31 ) of the first part (3) made from a polymeric material by heat pressing with a stencil mold (8).

10. Method according to claim 9, wherein the stencil mold (8) has at least one recess (81 ) which is large enough to encircle the pocket (7).11 . Method according to at least one of the preceding claims, wherein the insert (4) is in the form of a coating or in the form of a separating strip (41 ), preferably a separating strip (41 ) in the form of a paper strip especially preferred a wax coated paper strip.

12. A shoe sole (1 ) comprising a foamed component (2), which foamed component comprises a. a first part (3) made from a polymeric material; b. at least one insert (4), which is arranged at least partially on a first outer surface (31 ) of the first part (3); c. a second part (6), which is arranged on the first outer surface (31 ) of the first part (3) and thereby encloses the insert (4) whereby the second part (6) is bonded on the first outer surface (31 ) of the first part (3) except for the area (A) covered by the insert (4); d. a pocket (7) which is located between the separated first part (3) and the second part (6) and the insert (4) arranged within the pocket (7).

13. A shoe sole (1 ) according to claim 12, wherein the pocket (7) has a volume (V) of at least 225 mm3, more preferably of at least 500 mm3.

14. A shoe sole (1 ) according to at least one of claims 12 or 13, wherein the pocket (7) covers an area (A) of the first part (3) and / or the second part (6) of 50 mm2to 1900 mm2, more preferable between 150 mm2to 1300 mm2and / or has an aspect ratio in the range of 1 to 5, more preferable between 1 and 2.5.

15. A shoe sole (1 ) according to at least one of claims 12 to 14, wherein the first part (3) and the second part (6) are material bonded to each other at the first outer surface (31 ) of the first part (3) except for the area (A) of the first outer surface (31 ) on which the insert (4) is placed.

16. A shoe sole (1 ) according to at least one of claims 12 to 15, wherein the insert (4) is in the form of a coating or in the form of a separating strip (41 ), preferably a separating strip (41 ) in the form of a paper strip more preferably in the form of a wax coated paper strip.

17. A shoe sole (1 ) according to at least one of claims 12 to 16, wherein the insert (4) has a layout out of the group of the following: round, circular, elliptical, rectangular, squared.

18. A shoe sole (1 ) according to at least one of claims 12 to 17, wherein a number of inserts (4) are arranged between the first part (3) and the second part (6) and up to 75 %, preferably up to 50%, more preferably up to 25% of the area (A) of the first outer surface (31 ) of the first part (3) are covered by the number of inserts (4).

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