METHOD FOR PRODUCING AN OBJECT HAVING AN ELASTIC COMPRESSIBLE COMPOSITE BODY COMPRISING MULTIPLE ELEMENTS

Description

[0001] The invention relates to a method for producing an article, in particular an orthopedic article, such as a shoe insole, comprising an elastically compressible composite body comprising multiple elements. The invention further relates to a combination of articles comprising a first body made of a first expanded material and a second body made of a second material.

[0002] Articles comprising an elastically compressible composite body comprising multiple elements are known. They are used, for example, for orthopedic articles, such as shoe insoles. It is known to manufacture shoe insoles from multiple layers. The layers can, in particular, have different hardnesses and densities. In this way, the shoe insoles can be adapted to different requirements. In particular, a softer layer can be used to achieve good pressure distribution across the foot, while a harder layer provides stabilization. For this purpose, the layers can be pre-formed as a footbed. The layers can also be adapted to the user's weight, the intended use of the shoes (sports, use on the road, in the forest, etc.), and to misalignments of the foot.Such shoe insoles are particularly important for people with health restrictions, such as diabetes, as good pressure distribution is important in order to avoid circulatory problems in the foot.

[0003] DE 10 2004 014 609 A1 discloses a composite panel made of cross-linked foamed plastics in which the layers have different hardnesses. June 15, 2022

[0004] The composite sheet is manufactured by preparing two layers of the non-expanded plastic material and heating them together in a press. The layers are foamed, vulcanized together, and bonded together without adhesives. The disadvantage of this method is that a variety of combinations must be provided to allow for individual adjustment of the shoe insole.

[0005] It is also conceivable to provide expanded bodies made of cross-linked plastic individually. However, the bodies would then have to be assembled by the processor and bonded with an adhesive.

[0006] EP 3 267 817 A1 describes a method for producing a sole assembly. The described method involves first producing a sole-shaped preform in a first mold using pellets and another material. This preform may contain EVA. The preform is then placed together with a second preform in a second mold, where the preforms are melted together before the materials are expanded.

[0007] The invention aims to provide a method that simplifies the production of an article comprising an elastically compressible body comprising multiple elements. The invention also aims to provide a combination of articles that enables the simple production of an elastically compressible composite body comprising multiple elements.

[0008] The object is achieved by a method for producing an article, in particular an orthopaedic article, according to claim 1.

[0009] This considerably simplifies the manufacture of the article comprising the composite body having multiple elements. In particular, the first and second bodies can be joined together without the need to apply an adhesive or adhesive layer. Rather, permanent adhesion between the first and second bodies can be achieved simply by bringing the first contact surface of the first body into contact with the second contact surface of the second body after heating the bodies and keeping them in contact for a period of time. This can be done, for example, in a press commonly used in orthopedic technology, such as in particular in a thermoforming machine. This is possible because a thermoplastic bond can be achieved between the first and second materials due to the partial crosslinking of the first material and the non-crosslinking or partial crosslinking of the second material.In chemistry, crosslinking refers to reactions in which a large number of individual macromolecules are linked to form a three-dimensional network. In this process, intermolecular crosslinking bridges are formed. Partially crosslinked in this context means that crosslinking does not occur until complete crosslinking occurs. As a result, the processor, such as an orthopedic workshop or a shoemaker, can particularly easily keep bodies with different physical properties in stock and combine them as needed. This contributes to considerable simplification, since a large number of combinations can be produced using a small number of bodies with different physical properties. Production is particularly safe, since the articles according to the invention enable a reliable and permanent bond without the addition of adhesive.In particular, a high degree of strength in the connection between the elements can be achieved. The risk of using an unsuitable adhesive is eliminated. Furthermore, production is particularly quick and easy, as the addition of an adhesive can be omitted. This also contributes to cost savings. The claimed process can thus be used to produce a variety of orthopedic materials that, for example, have supporting properties in addition to cushioning. Due to the use of expanded materials, bodies are obtained that have pores and are therefore particularly compressible (preferably elastically compressible). This allows the production of a shoe insole, in particular, with bedding, cushioning, and stabilizing properties. The shoe insole has good durability and retains its elastic properties over a long period of time. The partial cross-linking of the expanded first material also contributes to this.

[0010] The above-mentioned object is also achieved by a combination of objects according to claim 14.

[0011] Such a combination of articles can be designed, in particular, as a cushioning orthopedic article, such as a shoe component, or used to manufacture such an article. The shoe component is preferably a shoe insert or a shoe insole.

[0012] Further features of the invention are described below. These features relate to the method according to the invention as well as the combination according to the invention, unless expressly stated otherwise.

[0013] According to the invention, the second material can be an expanded or non-expanded material. Both variants offer advantages with regard to adapting the elastic properties as well as the support properties of the article. If the second material is also expanded, particularly good cushioning properties and, at the same time, good bondability can be achieved.

[0014] A preferred embodiment of the invention provides that the second material is expanded, with the crosslinkable component of the second body comprising a crosslinkable polymer that is present in the second body in partially crosslinked form. This contributes to good stability and a secure connection between the first and second bodies.

[0015] Preferably, the first and second materials are thermoplastic materials.

[0016] The crosslinking reaction that leads to partial crosslinking can be achieved in various ways. According to the invention, partial crosslinking is preferably carried out through chemical crosslinking. However, a crosslinking reaction that leads to partial crosslinking can also be achieved through radiation crosslinking.

[0017] According to the invention, it is preferred that the crosslinkable component of the first and / or second material comprises at least one compound selected from a group consisting of a peroxide-crosslinkable thermoplastic polymer and a peroxide-crosslinkable thermoplastic elastomer. Preferably, the crosslinkable component contains a peroxide-crosslinkable thermoplastic polymer. It is particularly preferred if the crosslinkable component of the first and / or second material comprises a peroxide-crosslinkable thermoplastic polymer and a peroxide-crosslinkable thermoplastic elastomer. The aforementioned features enable the production of an elastically compressible article comprising multiple elements and having advantageous cushioning and stabilizing properties.

[0018] A particularly preferred embodiment of the invention provides that the crosslinkable component of the first and / or the second material comprises at least one compound selected from a group consisting of ethylene-butyl acrylate copolymer (EBA), ethylene-vinyl acetate copolymer (EVA), functionalized ethylene-butyl acrylate copolymer, functionalized ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-2-ethylhexyl acrylate copolymer, ethylene-acrylic ester copolymer, polyolefin (such as polyethylene (PE) or polypropylene (PP) among others in the following variants: very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), polyolefin elastomers (e.g.POE) and ethylene-propylene copolymer (EPM)), styrene-butadiene block copolymer (SBS), styrene-isoprene block copolymer (SIS), styrene-isoprene-butadiene block copolymer (SIBS), styrene-ethylene-butadiene block copolymer (SEBS), styrene-ethylene-propylene block copolymer (SEPS), high-styrene-butadiene copolymer (HSBR - preferably with a styrene content >50%), thermoplastic polyurethane (TPU). Low density polyethylene has a density between 0.915 g / cm 3 and 0.935 g / cm 3 . Very low density polyethylene has a density between 0.89 g / cm 3 and 0.915 g / cm 3 . Linear low density polyethylene has a density between 0.915 g / cm 3 and 0.930 g / cm 3 .

[0019] It is particularly preferred according to the invention if the crosslinkable component of the first and / or second material comprises ethylene-vinyl acetate copolymer (EVA). It is further preferred if the crosslinkable component of the first and / or second material comprises linear low-density polyethylene (LLDPE) and / or low-density polyethylene (LDPE). It is also preferred if the crosslinkable component of the first and / or second material comprises ethylene-vinyl acetate copolymer (EVA) and high-styrene-butadiene copolymer (HSBR) (with a styrene content of >50%). It is also preferred if the crosslinkable component of the first and / or second material comprises at least one of the compounds ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer and ethylene-(meth)acrylic acid copolymer.

[0020] A further preferred embodiment of the invention provides that the crosslinkable component additionally comprises a styrene-containing polymer. This enables the production of an elastically compressible article comprising multiple elements with advantageous cushioning and stabilizing properties. It can be provided that the crosslinkable component also comprises a non-styrene-containing polymer in addition to the styrene-containing polymer.

[0021] According to the invention, it is particularly preferred if the styrene-containing polymer comprises at least one compound selected from the group consisting of styrene-butadiene block copolymer (SBS), styrene-isoprene block copolymer (SIS), styrene-isoprene-butadiene block copolymer (SIBS), styrene-ethylene-butadiene block copolymer (SEBS), styrene-ethylene-propylene block copolymer (SEPS), and high styrene-butadiene copolymer (HSBR, preferably with a styrene content of >50%). It is particularly preferred according to the invention if the styrene-containing polymer comprises styrene-butadiene block copolymer and / or styrene-isoprene block copolymer.

[0022] A preferred embodiment provides that the styrene content of the styrene-containing polymer is more than 50%. Preferably, the styrene content is more than 60%. Furthermore, it is preferred if the styrene content of the styrene-containing polymer is less than 80%.

[0023] A further improvement in the properties of the multi-element compressible article is achieved by at least one of the first and second materials (preferably both) additionally comprising at least one crosslinkable elastomer, which is present in partially crosslinked form in the first and second materials, respectively. This enables the production of a multi-element elastically compressible article with advantageous cushioning and stabilizing properties. In particular, the crosslinkable elastomer can comprise a rubber compound. Preferably, the crosslinkable polymer is peroxide-crosslinkable.

[0024] According to the invention, it is preferred that the peroxide-crosslinkable elastomer comprises at least one compound selected from the group consisting of styrene-butadiene rubber (SBR), nitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM), natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), polyacrylate rubber (ACM), and polyethylene-acrylate rubber (AEM). Nitrile-butadiene rubber (NBR), isoprene rubber (IR), and natural rubber (NR), as well as mixtures thereof, are particularly preferred.

[0025] A further improvement provides that the crosslinkable component of the first body and the crosslinkable component of the second body comprise at least one matching crosslinkable polymer.

[0026] A preferred embodiment of the invention provides that the first and / or second expanded material comprises a filler. The filler can be used to adjust the hardness and density of the first and second expanded materials. Furthermore, the filler contributes to the high stability of the first and second materials. In this way, the filler can also improve the strength of the connection between the first and second bodies.

[0027] Preferably, the filler comprises at least one compound selected from a group consisting of chalk, carbon black, silica, silicic acid, kaolin, aluminum hydroxide, sodium aluminum silicate, glass flour, wood flour, nutshell flour, lignin and cellulose.

[0028] Preferably, a filler is added to the base material.

[0029] The second body can preferably be produced accordingly. Accordingly, it can be provided that the second body is produced by first preparing a second base material by mixing the crosslinkable component in uncrosslinked form, a chemical blowing agent, and a crosslinking agent. The chemical blowing agent and the crosslinking agent are then activated (preferably with the addition of energy) so that the base material expands and the crosslinkable component is partially crosslinked to obtain the expanded material of the second body with partially crosslinked polymers. A filler is preferably added to the base material.

[0030] On the other hand, it is also possible to produce the second body without a blowing agent in the second base material. The resulting second body is then unexpanded. A crosslinking agent can be included in the first base material if the polymers of the second body are to be partially crosslinked. However, production is also possible without a crosslinking agent. The polymers of the second base material then remain uncrosslinked.

[0031] Mixing can take place in a mixing unit, such as an internal mixer (e.g., kneader). The activation of the blowing agent and the crosslinking agent preferably takes place in a mold, for example, in the form of a hot press.

[0032] The first base material and optionally the second base material preferably contain at least one chemical blowing agent. A chemical blowing agent is understood to be a compound that decomposes upon exposure to heat, releasing gases.

[0033] Examples of suitable chemical blowing agents according to the invention are azo compounds, hydrazide compounds, nitroso compounds and carbazide compounds, such as azobisisobutyronitrile, azodicarbonamide (ADCA), di-nitroso-pentamethylenetetramine, 4,4'-oxybis(benzenesulfonic acid hydrazide) (OBSH), azocyclohexylnitrile, azodiaminobenzene, benzene-1,3-sulfonylhydrazide, calcium azide, 4,4'-diphenyldisulfonylazide, diphenylsulfone-3,3'-disulfohydrazide, benzene-1,3-disulfohydrazide, trihydrazinotriazine, p-toluenesulfonylhydrazide and p-toluenesulfonylsemicarbazide.

[0034] In the context of this embodiment, preparations have proven advantageous which contain an azodicarbonamide content of 0.5 to 8 wt.%, in particular of 2 to 5 wt.%, in each case based on the total mass of the first or second base material.

[0035] Furthermore, it is preferred that the first and / or second base material contain a chemical crosslinking agent. It can be provided that the crosslinking agent is contained in the first and second base materials, respectively, in an amount that enables partial crosslinking of the crosslinkable component, but is insufficient for complete crosslinking.

[0036] Preferably, the chemical crosslinking agent comprises a peroxide.

[0037] According to the invention, organic peroxides such as ketone peroxides, diacyl peroxides, peresters, perketals, and hydroperoxides are particularly preferred. Particularly preferred are, for example, cumene hydroperoxide, t-butyl peroxide, bis(tert-butylperoxy)diisopropylbenzene, di(tert-butylperoxyisopropyl)benzene, dicumyl peroxide, t-butyl peroxybenzoate, dialkyl peroxydicarbonate, diperoxyketals (e.g., 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane), ketone peroxides (e.g., methyl ethyl ketone peroxides), and 4,4-di-tert-butylperoxy-n-butyl valerate.Particularly preferred according to the invention are the peroxides marketed commercially, for example, by Akzo Nobel, such as 3,3,5,7,7-pentamethyl-1,2,4-trioxepane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hex-3-yne, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butylcumyl peroxide, di(tert-butylperoxyisopropyl)benzene, dicumyl peroxide, butyl 4,4-di(tert-butylperoxy)valerate, tert-butylperoxy-2-ethylhexyl carbonate, 1,1-di-(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butylperoxybenzoate, di-(4-methylbenzoyl)peroxide and dibenzoyl peroxide.

[0038] It has further proven advantageous according to the invention if the peroxides used are essentially inert at room temperature and are only activated upon heating to higher temperatures (for example, upon heating to temperatures between 130°C and 240°C). It is particularly advantageous according to the invention if the peroxide used has a half-life of more than 60 minutes at 65°C, i.e., after heating the first or second base material containing the peroxide to 65°C for 60 minutes, less than half of the peroxide used has decomposed. According to the invention, peroxides which have a half-life of 60 minutes at 115°C may be particularly preferred.

[0039] It may be particularly preferred according to the invention to use di(tert-butylperoxyisopropyl)benzene as peroxide; this is commercially available, for example, under the trade names Perkadox ®< 14-40 B-PD or Perkadox ®< 14-40 K PD from Akzo Nobel or under the trade names Peroxan ®< BIB 40 GS or Peroxan ®< BIB 40 P from Pergan.

[0040] In a further form according to the invention, it may also be preferred to use dicumyl peroxide, as sold, for example, under the trade names Perkadox ®< BC 40 K PD or Perkadox ®< BC 40 B PD by Akzo Nobel or under the trade names Peroxan ®< DC 40 GS, Peroxan ®< DC 40 P or Peroxan ®< DC 40 PK by Pergan.

[0041] The crosslinking agent is contained in the first or second base material to achieve the desired partial crosslinking preferably in an amount of 0.05 to 0.5 wt.%, in particular in an amount of 0.2 to 0.4 wt.%, in each case determined as the active substance content of peroxide based on the mass of the first or second base material.

[0042] A particularly preferred embodiment of the invention provides that the degree of crosslinking of the first body and / or the second body is below 92%. Particularly good properties are achieved when the degree of crosslinking is below 90%. Preferably, the degree of crosslinking of the first and / or second body is above 25%. It is preferred if the degree of crosslinking is above 50%, with a degree of crosslinking of more than 60% being particularly preferred.

[0043] Preferably, the aforementioned degree of crosslinking can be determined analogously to DIN 16892:2000-07. DIN 16892:2000-07 refers to pipes made of crosslinked high-density polyethylene. The standard describes a procedure for determining the degree of crosslinking, which can also be applied to the claimed first and second materials. The method is based on determining the degree of crosslinking by determining the mass fraction of the material that is insoluble in boiling xylene.

[0044] The procedure involves the following: Sampling: Samples are taken from the material in the form of small chips, e.g. shear shavings.

[0045] Procedure: From the sample taken (mass m 1 ), 0.5 g (+- 0.1 g) is weighed to 1 mg and placed in a container made of wire mesh or perforated sheet metal. The container with the sample is stored in boiling technically pure xylene. 1% antioxidant (2,2-methylene-bis-(4-methyl-6 tert-butylphenol) or pentaerythrityl tetrakis (3-(3,5 di-tert.butyl-4-hydroxyphenyl)-propionate)) is added to the solvent. The storage time is 8 h ± 5 min. The container with the residue is then removed from the still boiling solvent, cooled to room temperature and dried. The samples stored in xylene are dried for 3 h in an oven heated to 140 °C and operating in fresh air mode with forced ventilation. After cooling to room temperature, the mass of the residue (mass m 2 ) to 1 mg, Evaluation: The mass fraction insoluble in xylene corresponds to the degree of crosslinking G in % and is calculated according to equation (5): G = m 2 m 1 ⋅ 100

[0046] In this way, the degree of cross-linking G can be determined in %.

[0047] Since, under certain circumstances, ingredients other than non-crosslinked polymers (e.g. processing aids) may dissolve from the material under investigation when the sample is stored in xylene, the degree of crosslinking G, as previously determined analogously to DIN 16892:2000-07, may be slightly below 100% even for bodies containing a fully crosslinked polymer.

[0048] When producing an orthopaedic article, such as in particular a shoe insole, it can be provided that the first and the second body are cut before or after the production of the composite body.

[0049] When manufacturing an orthopedic article, such as a shoe insole, it can further be provided that the composite body is plastically deformable after heating. In this way, the composite body can be formed, for example, into a molded footbed.

[0050] An embodiment according to the invention provides that pigments and / or processing aids are added to the first and / or the second base material.

[0051] According to the invention, it is preferred that the crosslinkable elastomer is contained in the first and / or the second base material in an amount of between 5 and 30 parts by weight per 100 parts by weight of polymer.

[0052] The statement 100 parts by weight of polymer refers to the total mass of all polymers in the first and second base materials.

[0053] According to the invention, it is preferred that the styrene-containing polymer is contained in the first and / or second base material in an amount of between 5 and 30 parts by weight per 100 parts by weight of polymer. According to the invention, it is preferred that the filler is contained in the first and / or second base material in an amount of between 5 and 50 parts by weight per 100 parts by weight of polymer. According to the invention, it is preferred that the first and second bodies have different physical properties.

[0054] In particular, the first and second bodies can have different hardness and / or density. This allows a softer layer with good cushioning properties to be combined with a harder layer that provides good stabilization.

[0055] The Shore hardness can be determined according to DIN ISO 48-4: 2018-08.

[0056] According to the invention, the first body is softer than the second body.

[0057] According to the invention, the first body has a hardness between 5 and 50 Shore A.

[0058] According to the invention, the second body has a hardness between 20 and 75 Shore A.

[0059] According to the invention, it is further preferred that the density of the first and second bodies is between 0.05 and 0.7 g / cm 3 . Preferably, the density of the first body is lower than the density of the second body. Preferred values for the density of the first body are between 0.08 g / cm 3 and 0.3 g / cm 3 . Preferred values for the density of the second body are between 0.15 g / cm 3 and 0.5 g / cm 3 .

[0060] An advantageous embodiment provides that the connection between the first and second bodies is designed such that the peel resistance is between 0.5 N / mm and 5 N / mm. The peel resistance can be determined according to DIN EN 1392: 2006-08. Preferably, the peel resistance is between 1 N / mm and 3 N / mm.

[0061] An advantageous variant of the invention provides that the composite body is a laminated body, with the first body forming a first layer and the second body forming a second layer. Preferably, the first and second layers are arranged one above the other. In particular, the first and second layers can be arranged one above the other in a sandwich-like manner. Preferably, the first layer is arranged on the upper side of a shoe insole facing the foot. In this way, particularly good elastic properties can be achieved.

[0062] It is preferred that the layer thickness of the first and / or second layer is between 2 mm and 20 mm. Preferably, the layer thickness is between 3 mm and 10 mm.

[0063] According to the invention, the first body and the second body are plate-shaped. Sections of a size suitable for the production of a shoe insole can be cut from the plates.

[0064] A further design according to the invention provides that the first and second bodies are arranged in the same layer, with the first and second bodies each forming a section of the layer. In this way, different elastic or cushioning properties can be achieved in certain sections. At the same time, the first and second bodies can be securely connected according to the invention. For example, it is possible to arrange the first body next to the second body. Furthermore, it is possible for one of the first and second bodies to have a recess into which the other of the first and second bodies is inserted.

[0065] A preferred embodiment provides that the first expanded material is thermoplastically bonded directly to the second material at the joint formed by the first and second contact surfaces. In particular, a bond can exist between the first and second expanded materials, in which adhesive forces are directly present between the first and second expanded materials. In this context, "direct bond" means that the materials are directly bonded to one another without an intermediate layer and / or adhesive.

[0066] In order to achieve a thermoplastic bond, the first and second bodies can be heated to a temperature between 130°C and 170°C during the production of the composite body.

[0067] The period for which the first and second bodies are kept in contact with each other is preferably between 4 and 40 minutes.

[0068] Preferably, the first and / or second expanded material has open and / or closed pores. It is preferred if the first and / or second expanded material has closed pores.

[0069] It is also within the scope of the invention for the elastically deformable body to have more than two elements. Accordingly, it can be provided that at least one further body is provided which is designed like the first or second body and has a third contact surface. The first or the second body can have a fourth contact surface. The further body then lies with the third contact surface against the fourth contact surface. A permanent connection can be achieved, as between the first and the second body, without adhesive. Reference is made to the description of the first and the second body, which applies accordingly to the further body(s). With the help of the further body(s), for example, a three-layer or multi-layer structure of the compressible object can be achieved. In this case, the further body (or bodies) canThe additional bodies (the additional bodies) have physical properties that differ from the first and / or second bodies. In particular, the additional body can have a different hardness and / or density than the first and / or second bodies. This further improves the possibilities for achieving good cushioning and support at the same time. This is particularly advantageous for orthopedic applications.

[0070] According to the invention, the elastically compressible article comprising multiple elements can be an orthopedic padding and / or structural material. However, the elastically compressible article comprising multiple elements can also be designed for other technical applications.

[0071] Further objects, features, advantages, and possible applications of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawings. All described and / or illustrated features, individually or in any meaningful combination, constitute the subject matter of the invention, regardless of their combination in individual claims or their interrelations.

[0072] They show: Fig. 1: an article according to the invention with an elastically compressible composite body comprising two elements; Fig. 2: a shoe insert according to the invention with an elastically compressible composite body comprising two elements; Fig. 3: an article according to the invention with an elastically compressible composite body comprising three elements; and Fig. 4: another shoe insert according to the invention with an elastically compressible composite body comprising three elements; Fig. 5: another article according to the invention with an elastically compressible composite body comprising two elements; Fig. 6a: a side view of another article according to the invention with an elastically compressible composite body comprising three elements; Fig. 6b: the article from Fig. 6a in top view.

[0073] Figure 1shows a perspective view of a composite body 1 comprising several elements 2, 2'. The composite body 1 is elastically compressible. It comprises a first body 3 made of a first expanded material and a second body 4 made of a second material, which is preferably also expanded. The first and second expanded materials have pores and are elastically compressible.

[0074] The first and second bodies 3, 4 each form a layer of the composite body 1.

[0075] The first body 3 has a first contact surface 5. The second body 4 has a second contact surface 6. The first and second bodies 3, 4 rest against one another with the first and second contact surfaces 5, 6 and are permanently connected to one another at these. For this purpose, the expanded material of the first body 3 and the expanded material of the second body 4 each have a cross-linkable component that is in partially cross-linked form. The first body and the second body 3, 4 are thus directly connected to one another at the first and second contact surfaces 5, 6, as will be described in more detail below. An adhesive or an additional connecting layer is not provided between the first and second bodies.

[0076] Figure 1 shows a plate-like shape of the composite body 1. From the composite body 1, objects for a specific purpose, such as in particular the Figures 2 and 3 shown shoe insoles are manufactured.

[0077] The first and second bodies 3, 4 have different physical properties. Particularly for applications in the field of orthopedics and shoe insoles, it has proven effective if the hardness of the first and second bodies 3, 4 is between 5 Shore A and 75 Shore A. The first body 3 can be softer than the second body 4. The hardness can be adjusted, in particular, by the degree of expansion, the selection of the polymers used for the first and second expanded materials, and the amount of filler used. Greater expansion results in a larger pore volume and thus a softer material.

[0078] Furthermore, it can be provided that the densities of the first and second bodies 3, 4 differ. In particular, the density of the first and second bodies 3, 4 can be in the range between 0.05 g / cm 3 and 0.7 g / cm 3 . In particular, the first body 3 can have a lower density than the second body 4. It is preferred if the density of the first body 3 is between 0.08 g / cm 3 and 0.3 g / cm 3 . For the density of the second body 4, values between 0.15 g / cm 3 and 0.5 g / cm 3 are preferred. The density of the first and second bodies 3, 4 can also be adjusted by the degree of expansion of the expanded material. A higher expansion leads to a larger total pore volume and thus to a lower density. The density is also influenced by the amount and type of filler used.

[0079] The layer thickness 7, 8 of the first and second bodies 3, 4 can be configured differently depending on the intended application. Preferably, the layer thickness of the elements 2, 2' formed by the first and second bodies 3, 4 is between 2 mm and 20 mm each.

[0080] The first and second bodies 3, 4 are permanently connected to each other. The strength of the connection between the first and second bodies 3, 4 can be verified by determining the peel resistance. The peel resistance can be determined in accordance with DIN EN 1392: 2006-08.

[0081] The first and second bodies 3, 4 are initially manufactured separately, as explained in more detail below. In order to join the first and second bodies 3, 4 to one another, the first and second bodies 3, 4 are heated and then arranged one on top of the other so that they rest against one another at the first and second contact surfaces 5, 6. They are then held in contact with one another under pressure for a period of time T while cooled down. This can be done in particular in an orthopedic thermoforming device. Heating to temperatures between 130 °C and 170 °C is suitable. The period of time T is preferably between 4 minutes and 40 minutes. This results in a permanent connection directly between the first body 3 and the second body 4, without the need to add adhesive.

[0082] Figure 2 shows a shoe insert 10 with a composite body 1. The shoe insert is made of a composite body 1, as in Figure 1Accordingly, the shoe insert 10 comprises the layered elements 2, 2', which are formed by the first and second bodies 3, 4.

[0083] Figure 3 shows an article with a composite body 1' comprising three elements 2, 2', 2". The elements 2, 2', 2" are arranged as layers. The composite body 1' has, in addition to the first body 3 and the second body 4, which, as in the case of the Figure 1 illustrated embodiment, a further body 11. The further body 11 has a third contact surface 12. A fourth contact surface 13 is formed on the second body 4. The second body 4 and the further body 11 abut one another with the third and fourth contact surfaces 12, 13.

[0084] The additional body 11 is essentially designed like the first body 3 or the second body 4. The description of the first body 3 and the second body 4 should therefore also apply accordingly to the additional body 11. However, the additional body 11 can have different physical properties and in particular a different hardness and / or density than the first body 3 and / or the second body 4. The hardness and density can be within the ranges specified for the first and second bodies 3, 4. In this way, orthopedic articles, such as shoe insoles, can be produced which have particularly favorable properties. In particular, elastic and stabilizing properties can be combined in this way and adapted to the respective application.

[0085] Figure 4 shows a shoe insert 10' with a composite body 1'. The shoe insert 10' is made of a composite body 1', as in Figure 3shown. Accordingly, the shoe insert 10' comprises the elements 2, 2', and 2", which are formed by the first, second, and further bodies 3, 4, 11.

[0086] The shoe insoles 10, 10' can be manufactured using the composite body 1 or 1', respectively. For this purpose, a section corresponding to the foot size is cut out of the composite body 1 or 1', respectively, if it is larger than required. The composite body 1, 1' can then be subjected to a shaping step to obtain a shape adapted to the arch of the foot. Due to the thermoplastic properties of the composite body 1 or 1', respectively, a permanent shaping can be achieved by reheating the composite body 1 or 1' and placing it on a correspondingly shaped body, such as a baseboard.

[0087] In the same way, objects for other purposes can also be produced.

[0088] Figure 5 shows a further embodiment. This comprises a composite body 1" having several elements 2, 2'. Element 2 is formed by the first body 3, and element 2' is formed by the second body 4. Figure 5 shows that the first and second bodies 3, 4 are arranged side by side. The first and second contact surfaces 5, 6 are arranged on the end faces of the first and second bodies 3, 4, respectively.

[0089] The first and second bodies 3, 4 are like the first and second bodies 3, 4 of the related Figure 1 described composite body 1. Reference is made to the relevant description.

[0090] Figure 5shows that the composite body 1" in the illustrated embodiment has a layer in which the first and second bodies 3, 4 are arranged next to one another. In this way, different physical properties can be achieved in different areas of the composite body 1".

[0091] Figures 6a and 6b show a further embodiment of a composite body 1‴. The illustrations show that the composite body 1‴ comprises a first body 3, a second body 4, and a further body 11. The second body 4 has recesses 20, 21 in which the first body 3 and the further body 11 are arranged. This results in a composite body 1‴ with several elements 2, 2', 2", which are arranged in a layer of the composite body 1‴.

[0092] Figure 6ashows by the dashed arrangement that the composite body 1‴ can furthermore have a further layer with a further body 11'.

[0093] The first and second bodies 3, 4 are in turn connected to each other at the first and second contact surfaces 5, 6. The same applies to the third and fourth contact surfaces 12, 13, where the second body 4 is connected to the further body 11. The first and second bodies 3, 4, as well as the further body 11, also have contact surfaces with which they rest against the (optional) further body 11' and are connected to it. This connection is also made in the manner described without adhesive.

[0094] The following describes the production of the first body 3, the second body 4, and the additional bodies 11 and 11', respectively. The production is explained using the example of the first body 3. The second body 4 and the additional body 11 and 11', respectively, can essentially be produced in the same way. Therefore, the following description also applies to the production of the second and additional bodies 4, 11, and 11'.

[0095] The first body 3 is produced by first preparing a first base material. For this purpose, a crosslinkable component in uncrosslinked form, a chemical blowing agent, and a crosslinking agent are combined and mixed. A filler and additives, such as pigments, can also be added. Mixing can take place, for example, in a commercially available internal mixer. The first base material can then be placed into a rectangular mold, for example, to produce the first body 3. After the first base material has been introduced into the mold, the chemical blowing agent and the crosslinking agent are activated by applying heat. This can be done in a heating press. The base material expands and forms a pore-containing structure. The crosslinkable polymer is crosslinked. This is done in such a way that only partial crosslinking of the crosslinkable polymer is achieved.This creates an elastically compressible body.

[0096] The second body 4 and the further body 11 or 11' can be manufactured in the same way. It is also possible to produce the second body 4 and / or the further body 11 or 11' without a blowing agent. This results in a non-expanded version of the second or further body 4, 11. The second body 4 and / or the further body 11 can be manufactured with or without a crosslinking agent. If the production takes place without a crosslinking agent, the crosslinkable component of the second or further body 4, 11 remains uncrosslinked.

[0097] The crosslinkable component comprises at least one of the compounds listed in Table 1 below. Table 1: Networkable component Ethylene vinyl acetate copolymer (EVA) functionalized ethylene-butyl acrylate copolymer functionalized ethylene-vinyl acetate copolymer Ethylene-ethyl acrylate copolymer Ethylene-methyl acrylate copolymer Ethylene-(meth)acrylic acid copolymer Ethylene-2-ethylhexyacrylate copolymer Ethylene-acrylate copolymer Polyolefin, such as polyethylene (PE) or polypropylene (PP) in the following variants, among others: Very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), polyolefin elastomers (e.g. POE) and ethylene propylene copolymer (EPM) Styrene-butadiene block copolymer (SBS) Styrene-isoprene block copolymer (SIS) Styrene-isoprene-butadiene block copolymer (SIBS) Styrene-ethylene-butadiene block copolymer (SEBS) Styrene-ethylene-propylene block copolymer (SEPS) High-styrene-butadiene copolymer (HSBR, styrene content >50%) Thermoplastic polyurethane (TPU)

[0098] Furthermore, it can be provided that the crosslinkable component additionally comprises a styrene-containing polymer. The styrene-containing polymer can contain at least one of the compounds listed in Table 2. Table 2: Styrene-containing polymer Styrene-butadiene block copolymer (SBS) Styrene-isoprene block copolymer (SIS) Styrene-isoprene-butadiene block copolymer (SIBS) Styrene-ethylene-butadiene block copolymer (SEBS) Styrene-ethylene-propylene block copolymer (SEPS) High styrene-butadiene copolymer (HSBR, preferably styrene content >50%)

[0099] Furthermore, it may be provided that a crosslinkable elastomer is added to the respective base material. The crosslinkable elastomer may, in particular, comprise at least one of the rubber compounds listed in Table 3. Table 3: Crosslinkable elastomer Styrene-butadiene rubber (SBR) Nitrile butadiene rubber (NBR) Ethylene propylene diene rubber (EPDM) Natural rubber (NR) Isoprene rubber (IR) Butadiene rubber (BR) Polyacrylate rubber (ACM) Polyethylene acrylate rubber (AEM)

[0100] The blowing agent serves to expand the base material to obtain an expanded and thus porous body. Examples of blowing agents provided according to the invention include, in particular, azo compounds, hydrazide compounds, nitroso compounds, and carbazide compounds.

[0101] In particular, the chemical blowing agent may comprise at least one of the compounds listed in Table 4. Table 4: Propellant Azobisisobutyronitrile Azodicarbonamide (ADCA) Di-nitroso-pentamethylenetetramine 4,4'-Oxybis(benzenesulfonic acid hydrazide) (OBSH) Azocyclohexylnitril Azodiaminobenzene Benzene-1,3-sulfonylhydrazide Calcium azide 4,4'-Diphenyldisulfonyl azide Diphenyl sulfone-3,3'-disulfohydrazide Benzene-1,3-disulfohydrazide Trihydrazinotriazin p-Toluenesulfonylhydrazide p-Toluenesulfonylsemicarbazide

[0102] For each base material, a chemical crosslinking agent is also added. The crosslinking agent can, in particular, be a peroxide. In particular, the crosslinking agent can comprise at least one of the compounds listed in Table 5. Table 5: Crosslinking agents Cumene hydroperoxide t-butyl peroxide Bis(tert-butylperoxy)diisopropylbenzene Di(tert-butylperoxyisopropyl)benzene Dicumyl peroxide t-Butyl peroxybenzoate Dialkyl peroxydicarbonate Diperoxyketals (e.g. 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane) Ketone peroxides (e.g. methyl ethyl ketone peroxides) 4,4-Di-tert-butylperoxy-n-butyl-valerate 3,3,5,7,7-Pentamethyl-1,2,4-trioxepane 2,5-Dimethyl-2,5-di(tert-butylperoxy)hex-3-yne Di-tert-butyl peroxide 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane tert-butylcumyl peroxide Di(tert-butylperoxyisopropyl)benzene Dicumyl peroxide Butyl 4,4-di(tert-butylperoxy)valerate tert-Butylperoxy-2-ethylhexyl carbonate 1,1-Di-(tert-butylperoxy)-3,3,5-trimethylcyclohexane tert-butyl peroxybenzoate Di-(4-methylbenzoyl) peroxide Dibenzoyl peroxide

[0103] The crosslinking agent is added to the respective base material in an amount that allows partial crosslinking of the crosslinkable component under the given process conditions, but is too small for full crosslinking.

[0104] A filler can also be added to the respective base material. The filler preferably comprises at least one of the compounds listed in Table 6. Table 6: filler Silica chalk soot Silica kaolin aluminum hydroxide Sodium aluminum silicate Glass powder wood flour Nutshell flour lignin cellulose

[0105] The substances listed in Tables 1 to 6 are all commercially available.

[0106] Individual examples of implementation are described below.

[0107] Tables 7, 8 and 9 show compositions that can be used for the first base material of the first body 3, the second base material of the second body 4 and the further base material of the further bodies 11, 11', respectively. Table 7: Recipe number 1 2 3 4 5 6 7 8 9 Ethylene-vinyl acetate copolymer 100 100 100 100 100 100 100 100 100 Filler (silica) 10 10 10 10 10 10 10 10 10 Pigments, processing aids 8 8 8 8 8 8 8 8 8 Propellant (azodicarbonamide) 5 5 5 5 5 5 5 5 5 Crosslinking agent with peroxide content of 40% 0,3125 0,5 0,625 0,8125 0,9375 1,25 1,563 1,875 2,8125 Crosslinking agent only active substance 0,125 0,2 0,25 0,325 0,375 0,5 0,6252 0,75 1,125 Peel resistance (N / mm) 2,1 M 2,2 M 2,5 M 2,3 M 1,4 0,9 0,2 0,2 no bonding Degree of networking 25 80 83 86 89 90 93 94 fully networked

[0108] Table 7 shows nine different formulations. The weight percentages are based on the total amount of polymer. For example, the specification "100" for ethylene-vinyl acetate copolymer and "10" for silica means that 10 parts by weight (e.g., 10 kg) of silica are added to the mixture for every 100 parts by weight (e.g., 100 kg) of ethylene-vinyl acetate copolymer. The same applies to the other components of the mixture.

[0109] The exemplary formulations listed in Table 7 each contain ethylene-vinyl acetate copolymer as the crosslinkable component. They also contain pigments and processing aids, as well as azodicarbonamide as a blowing agent. Processing aids can include zinc carbonate or zinc oxide, for example, which enhance the effect of the blowing agent and can thus be used as accelerators in the manufacturing process.

[0110] Formulations 1 to 9 each contain the same amount of ethylene-vinyl acetate copolymer (100 parts), filler (10 parts), pigments and processing aids (8 parts), and blowing agent (5 parts). However, formulations 1 to 9 contain a different amount of crosslinking agent. The specified amount refers to the active ingredient. For ease of processing, the crosslinking agent may contain a carrier substance in addition to the active ingredient. The crosslinking agent used in each formulation has a peroxide content of 40%.

[0111] The content of crosslinking agent in formulations 1 to 9 varies between 0.125 and 1.125 parts by weight per 100 parts by weight of the total polymer amount.

[0112] Individual sheet-shaped bodies were then produced from each formulation. This was achieved by mixing the components of the formulation in an internal mixer to form a base material, which was then poured into a rectangular mold. The crosslinking agent and blowing agent were then activated to produce the expanded material body. This was achieved by heating the base material in a hot press at 170 °C for a period of 26 minutes. The body was then removed from the mold and cooled.

[0113] Table 7 also indicates the stability of the connection between the first and second body 3, 4. In determining the stability of the connection, two identically formed bodies of the same recipe as in Figure 1The two bodies were arranged and connected to each other as shown. The layer thicknesses 7, 8 of the first and second bodies 3, 4 were each 4 mm. The connection was achieved by heating the two bodies to a temperature of 130 °C for 4 minutes and then bringing them into contact with each other via the first and second contact surfaces 5, 6. They were then kept in contact for a period of 16 minutes while cooling. This takes place in a deep-drawing device at an overpressure of 1 bar.

[0114] The value specified for the connection is the peel resistance determined according to DIN 1329. If an "M" is indicated after the value in the table, this means that the material of the first or second body 3, 4 cracked at the value specified for the peel resistance without the connection between the first and second body 3, 4 becoming loose.

[0115] The table also indicates the degree of crosslinking G. The degree of crosslinking G was determined in the manner described above, analogous to DIN 16892.

[0116] Table 7 clearly shows that the amount of crosslinking agent added can control whether partial or full crosslinking is achieved in the finished product. Furthermore, while other process parameters, such as temperature, remain constant, the degree of partial crosslinking can be adjusted by varying the amount of crosslinking agent.

[0117] Formulation 9 shows a comparative example not according to the invention. Due to the addition of the crosslinking agent in an amount of 1.125 parts by weight per 100 parts by weight of polymer, very strong crosslinking is achieved, which cannot be further increased even by further increasing the amount of crosslinking agent. With such a fully crosslinked material, a permanent bond between the first and second bodies 3, 4 cannot be achieved in the manner described above without an adhesive. A peel resistance cannot therefore be determined. Two bodies manufactured according to Formulation 9 can therefore only be permanently bonded to one another by adding an additional adhesive or an adhesive layer.

[0118] This is different for formulations 1 to 8. Due to the use of the crosslinking agent in a reduced amount compared to formulation 9, partial crosslinking of the crosslinkable polymer is achieved. This makes it possible to bond a first and a second body 3, 4 together in the manner described above, without the addition of an adhesive or adhesive layer. Formulations 1 to 8 show an increasing degree of crosslinking, which was determined in the manner described above. This ranges from 25% for formulation 1 to 94% for formulation 8. Formulations 7 and 8, with a higher degree of crosslinking, have a less strongly developed bond. Accordingly, the peel resistance of 0.2 N / mm is still quite low. However, examples 7 and 8 show that even a slight reduction in the degree of crosslinking compared to formulation 9 results in a bond between the bodies.

[0119] In formulations 1 to 6, further reduced amounts of crosslinking agent were used compared to formulations 7 and 8. This results in an increase in the bond strength. Accordingly, higher peel resistance values can be achieved. The examples also show that a degree of crosslinking of 90% already produces a significantly improved bond with a considerably improved peel resistance. By reducing the degree of crosslinking to values of less than 90%, this can be significantly increased again. Even with a degree of crosslinking of only 25%, a very stable bond between the first and second bodies 3, 4 with a peel resistance of 2.1 N / mm is achieved. However, an excessive reduction in the degree of crosslinking can reduce the stability of the composite body 1, 1'. Therefore, a degree of crosslinking above 50% is particularly preferred. A degree of crosslinking above 80% is particularly preferred. Table 8: Recipe number 10 11 12 13 LDPE 75 75 75 75 LLDPE 25 25 25 25 Filler (silica) 9,5 9,5 9,5 9,5 Pigments, processing aids 5 5 5 5 Propellant (azodicarbonamide) 2,75 2,75 2,75 2,75 Crosslinking agent with 40% peroxide content 0,625 0,8125 0,9375 1,25 Crosslinking agent only active substance 0,25 0,325 0,375 0,5 Peel resistance (N / mm) 0,6 M 0,6 M 1,5 M 1,5 M Degree of cross-linking (%) 2 58 70 75

[0120] Table 8 shows four additional formulations. These each contain LDPE and LLDPE as crosslinkable components. They also contain silica as a filler, as well as pigments, processing aids, and blowing agents. In Table 8, the amounts of crosslinking agent were also varied for the different formulations. The degree of crosslinking determined ranged from 2% to 75%. Values between 0.6 N / mm and 1.5 N / mm were determined for the peel strength. For all of the formulations presented in Table 8, material fracture occurred during the peel strength determination. This means that the bond between the first and second bodies 3, 4 was more stable than the material itself. Table 9: Recipe number 14 15 16 17 Ethylene-vinyl acetate copolymer 75 75 87,5 75 High-styrene resin polymer 25 25 --- --- NBR --- --- 12,5 --- SBS --- --- --- 25 Silica 8 8 9,5 9,5 Pigments, processing aids 2 2 5 5 propellants, e.g. B. Azodicarbonamide 2,19 1,47 2,75 2,75 Crosslinking agent with 40% peroxide content 0,7 0,867 0,81 0,5 Crosslinking agent only active substance 0,28 0,3468 0,324 0,2 Peel resistance (N / mm) 2,6 M 1,3 M 1,8 M 1,2 M Degree of cross-linking (%) 91 85 85 82

[0121] Table 9 shows four additional formulations. These contain ethylene-vinyl acetate copolymer as the crosslinkable component. Formulations 14 and 15 also contain high-styrene resin polymer. Formulations 16 and 17 each contain a crosslinkable elastomer. Formulation 16 contains NBR, and Formulation 17 contains SBS. The determined degree of crosslinking G is between 82% and 91%.

[0122] For all four formulations in Table 9, a good bond was achieved between the first and second bodies 3 and 4. The determined peel strength ranged from 1.2 N / mm to 2.6 N / mm. Material failure occurred in all cases during the peel strength determination. This indicates that the bond exhibits greater strength than the material itself.

Claims

1. Method for manufacturing an object, in particular an orthopaedic object (10, 10'), with an elastically compressible composite body (1, 1') having a plurality of elements (2, 2', 2"), comprising: - providing a first plate-shaped body (3) of a first material, wherein the first material is expanded, wherein the first body (3) has a first contact face (5), - providing a second plate-shaped body (4) of a second material, wherein the second body (6) has a second contact face, wherein the first and the second material each include a crosslinkable component comprising a crosslinkable polymer, wherein the crosslinkable polymer of the first body (3) is in a partially crosslinked form, wherein the crosslinkable polymer of the second body (4) is in a partially crosslinked form, wherein the first body (3) is manufactured in that initially a first base material is manufactured, by mixing together the crosslinkable component in uncrosslinked form, a chemical blowing agent and a crosslinking agent, in that subsequently the chemical blowing agent and the crosslinking agent are activated in such a way that the base material expands and the crosslinkable polymer becomes partially crosslinked, so as to obtain the expanded material of the first body with partially crosslinked polymers, wherein the first body (3) is softer than the second body (4), wherein the first body has a hardness between 5 and 50 Shore A, wherein the second body has a hardness between 20 and 75 Shore A, and - manufacturing the composite body (1, 1') with a durable connection between the first and the second body (3, 4), in that the first body (3) and the second body (4) are heated and the first contact face (5) of the first body (3) is brought into contact with the second contact face (6) of the second body (4) and held in contact for a period of time.

2. Method according to claim 1, characterised in that the crosslinkable component of the first and / or of the second material comprises at least one compound selected from a group consisting of a peroxide-crosslinkable thermoplastic polymer and a peroxide-crosslinkable thermoplastic elastomer.

3. Method according to claim 2, characterised in that the crosslinkable component of the first and / or of the second material comprises at least one compound selected from a group consisting of ethylene butyl acrylate copolymer (EBA), ethylene vinyl acetate copolymer (EVA), functionalised ethylene butyl acrylate copolymer, functionalised ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene methyl acrylate copolymer, ethylene (meth)acrylic acid copolymer, ethylene 2-ethylhexyl acrylate copolymer, ethylene acryl ester copolymer, polyolefin, styrene butadiene block copolymer (SBS), styrene isoprene block copolymer (SIS), styrene isoprene butadiene block copolymer (SIBS), styrene ethylene butadiene block copolymer (SEBS), styrene ethylene propylene block copolymer (SEPS), high styrene butadiene copolymer (HSBR) and thermoplastic polyurethane (TPU).

4. Method according to any of claims 1 to 3, characterised in that the crosslinkable component comprises a styrene-containing polymer.

5. Method according to any of claims 1 to 4, characterised in that at least one of the first and the second material additionally includes at least one crosslinkable elastomer, which is present in the first and / or second expanded material in a partially crosslinked form.

6. Method according to any of claims 1 to 5, characterised in that the first and / or the second material includes a filler.

7. Method according to any of claims 1 to 6, characterised in that the second body (4) is manufactured in that initially a second base material is manufactured, by mixing together the crosslinkable component in uncrosslinked form, a chemical blowing agent and a crosslinking agent, in that subsequently the chemical blowing agent and the crosslinking agent are activated in such a way that the second base material expands and the crosslinkable polymer becomes partially crosslinked, so as to obtain the expanded second material of the second body with partially crosslinked polymers.

8. Method according to any of claims 1 to 7, characterised in that, to obtain the desired partial crosslinking, the crosslinking agent in the first base material is preferably contained in an amount of 0.05 to 0.5 % by weight, determined as a peroxide active substance content based on the mass of the first and / or second base material.

9. Method according to any of claims 1 to 8, characterised in that the crosslinking agent comprises a peroxide.

10. Method according to any of claims 1 to 9, characterised in that the degree of crosslinking of the first body and / or of the second body is below 92%.

11. Method according to any of claims 1 to 10, characterised in that the degree of crosslinking of the first body (3) and / or of the second body (4) is over 25%.

12. Method according to any of claims 1 to 11, characterised in that the first and the second body (3, 4) have different physical properties.

13. Method according to claim 12, characterised in that the density of the first and of the second body (3, 4) is between 0.05 g / cm3 and 0.7 g / cm3.

14. Combination of objects, comprising - a first plate-shaped body (3) of a first material which is expanded and comprises a crosslinkable component, wherein the crosslinkable component comprises a crosslinkable polymer which is present in the first body (3) in a partially crosslinked form, wherein the first body (3) has a first contact face (5), and - a second plate-shaped body (4) of a second material which comprises a crosslinkable component, wherein the crosslinkable component comprises a crosslinkable polymer which is present in the second body (4) in an uncrosslinked or partially crosslinked form, wherein the second body (4) has a second contact face (6), wherein the first and the second body (3, 4) are interconnectable or interconnected at the first and the second contact face (5, 6), wherein the first body (3) is manufactured in that initially a first base material is manufactured, by mixing together the crosslinkable component in uncrosslinked form, a chemical blowing agent and a crosslinking agent, in that subsequently the chemical blowing agent and the crosslinking agent are activated in such a way that the base material expands and the crosslinkable polymer becomes partially crosslinked, so as to obtain the expanded material of the first body with partially crosslinked polymers, wherein the first body is softer than the second body, wherein the first body has a hardness between 5 and 50 Shore A, wherein the second body has a hardness between 20 and 75 Shore A.

15. Shoe component, comprising a combination of objects according to claim 14, wherein the first contact face (5) of the first body (3) is positioned against the second contact face (6) of the second body (4), wherein the first body (3) and the second body (4) are durably connected.