EP4608903A1

EP4608903A1 - Expanded thermoplastic polyurethane for special molding process

Info

Publication number: EP4608903A1
Application number: EP23798747.4A
Authority: EP
Inventors: Peter Gutmann; Lisa Marie Schmidt; Elmar Poeselt; Martin Vallo; Christian-Andreas WINKLER
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2022-10-28
Filing date: 2023-10-27
Publication date: 2025-09-03
Also published as: WO2024089264A1; CN120112589A

Abstract

The present invention is directed to a process for the preparation of a molded body comprising expanded particles comprising a thermoplastic elastomer, comprising the steps of loading the expanded particles comprising a thermoplastic elastomer into a mold, and fusing the expanded particles comprising a thermoplastic elastomer by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 80 to 250 kg/mol. The invention is further directed to the molded body obtained in the process as well as the use thereof in shoe soles, part of shoe soles, shoe intermediate soles, shoe insoles, damping elements, cushioning elements, underlays, grips, flooring, mattresses, sporting goods, bicycle saddles, tires and in automotive interiors and exteriors.

Description

Expanded thermoplastic polyurethane for special molding process

The present invention is directed to a process for the preparation of a molded body comprising expanded particles comprising a thermoplastic elastomer, comprising the steps of loading the expanded particles comprising a thermoplastic elastomer into a mold, and fusing the expanded particles comprising a thermoplastic elastomer by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 80 to 250 kg/mol, preferably in the range of 100 to 200 kg/mol determined by means of gel permeation chromatography The invention is further directed to the molded body obtained in the process as well as the use thereof in shoe soles, part of shoe soles, shoe intermediate soles, shoe insoles, damping elements, cushioning elements, underlays, grips, flooring, mattresses, sporting goods, bicycle saddles, tires and in automotive interiors and exteriors.

The preparation of expanded thermoplastic elastomer bead foams is described within WO2014/198779 A1 using the extrusion technology while the preparation of parts out of the expanded thermoplastic elastomer beads is not explained.

WO2015/052265 also describes the preparation of expanded beads out of thermoplastic elastic polymers using an autoclave to impregnate the compact material. Afterwards, the impregnated beads can be foamed and in a special case directly molded to a part reducing the pressure within the autoclave. In another possibility, the impregnated beads are taken out and heated to the foaming temperature in a separate machinery. In case, single foamed beads are achieved, the part preparation is not further described.

Bead foams, such as polypropylene or polystyrene bead foams, typically are fused together with superheated water vapor in automatic molding machines to form shaped parts for the packaging industry for example. TPU bead foams can be further processed not only by superheated steam fusion but also by in situ foaming or adhering with reactive polyurethane systems. Since superheated steam fusion has very high energy requirements, alternatives are sought. Fusion by means of hot air is possible in principle, but does not as yet yield satisfactory parts owing to unsatisfactory distribution, and requires long cycle times because of the low energy content of hot air and the poor thermal conduction of closed-cell foams.

The molding of expanded thermoplastic polyurethane bead foams is described in DE102013110242 A1. Here, different variations on filling the mold are explained all with the intention to have a fully filled cavity. Therefore, filling under pressure or with crack that is closed before molding are mentioned. Within all these variants, the filling is occurred by pressing more material into the cavity increasing the overall weight and density of the part. Regarding molding steam molding is used. Using electromagnetic radiation or an electromagnetic field to provide the energy for molding is described in general in EP3698949 A1 and WO2017/125410 A1 for different expanded thermoplastic beads. Especially in WO2017/125410 A1 it is shown that a homogeneous foamed part can be achieved using an electromagnetic field to apply the energy.

Improving the molding by using electromagnetic fields, a special mold design is described in EP3808522 A1. Here, the mold is separated in cavities to adjust the electromagnetic field and improve homogeneity of molding.

Foam moldings comprising expanded thermoplastic polyurethane are widely used for sports apparel, shoes, and shoe parts as well as for cushioning elements.

WO 2017/125410 A1 relates to a method for producing a particle foam part wherein foam particles are heated in a mold such that they weld together. This foam particles are made from polyurethane (PU), polylactide (PLA), polyethylene block amide (PEBA) or from polyethylene terephthalate (PET). The heat is guided by means of electromagnetic RF radiation to the foam particles. In case of large or thick particle foam parts it is described that they heat up more strongly in the middle than in the edge region. An increase of the energy input by the electromagnetic field leads to a complete melting of the foam particles in the central area of the particle foam part.

An alternative way of bonding the foam beads together thermally is by high-frequency fusion as described inter a/ia'wx \NO 2001/64414. In high-frequency fusion, the foamed beads, in particular of expandable polystyrene (EPS), expanded polypropylene (EPP) or expandable polyethylene terephthalate (EPET) which are to be fused together are surrounded with a liquid medium absorbing electromagnetic radiation, water for example, and then joined together by applying a form of electromagnetic radiation such as, for example, microwaves. Owing to the water imbibition due to the higher polarity of thermoplastic polymers, this process is only marginally possible for foam beads comprising thermoplastic elastomers. In addition, the 100°C temperature attainable on boiling water under atmospheric pressure is usually insufficient to fuse the elastomer beads together. The water imbibition allows the water to penetrate excessively into the beads, and the heating is effective not just at the points of contact but also within the beads. As a result, the beads may collapse prior to being fused.

DE 10 2013 012 515 A1 describes a process for joining foam beads, in particular EPP or EPS, together thermally by inductive heating with an improved energy balance. However, the production of shaped parts by inductive heating presupposes some electrical conductivity on the part of the beads, at least at the surfaces to be joined together. This is attainable by coating with electrically conductive fillers such as, for example, metallic powder or carbon black, nanotubes. Spraying is an example of a possible way to coat the beads.

WO 2019/162172 A1 discloses a method for producing bead foams from foam beads based on thermoplastic elastomers, which comprises foam beads being wetted with a polar liquid and joined together thermally in a mold via high-frequency electromagnetic radiation. The use of additives in the molding process makes the process less efficient and increases the costs.

The problem addressed by the present invention was that of remedying the disadvantages mentioned and of providing a method for producing molded bodies in a simple cost efficient process.

According to the present invention, this problem is solved by a process for the preparation of a molded body comprising expanded particles comprising a thermoplastic elastomer, comprising the steps of

(i) loading the expanded particles comprising a thermoplastic elastomer into a mold,

(ii) fusing the expanded particles comprising a thermoplastic elastomer by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 80 to 250 kg/mol.

It has been surprisingly found that the use of a thermoplastic elastomer with a molecular weight Mw in the range of from 80 to 250 kg/mol allows to prepare molded bodes in a simple manner. It has been found that the temperature increase which occurs by the stimulation of the thermoplastic elastomer with energy at least partially through an electromagnetic field is sufficient to result in thermally molding the particles.

Unless otherwise noted, the molecular weight Mw of the thermoplastic elastomer is determined using GPC in the context of the present invention. Unless otherwise stated in the context of the present invention the determination of the weight average molecular weights Mw of the thermoplastic elastomers, dissolved in HFIP (hexafluoroisopropanol), is effected by means of GPC using the thermoplastic elastomers, dissolved in HFIP (hexafluoroisopropanol). Determination of the molecular weight is effected by means of two GPC columns arranged in series (PSS-Gel; 100A; 5p; 300*8 mm, Jordi-Gel DVB; MixedBed; 5p; 250*10 mm; column temperature 60° C.; flow 1 mL/min; Rl detector). Calibration is performed with polymethyl methacrylate (EasyCal; from PSS, Mainz) and HFIP is used as eluent.

Useful thermoplastic elastomers include, for example, thermoplastic polyurethanes (TPU), thermoplastic polyester elastomers (e.g., polyether esters and polyester esters), thermoplastic copolyamides (e.g., polyether copolyamides) or thermoplastic styrene-butadiene block copolymers. Foam beads based on thermoplastic polyurethane (TPU) are particularly preferred.

The thermoplastic elastomers employed to produce the foam beads preferably have a Shore hardness in the range from 25A to 82D, preferably in the range from 50A to 60D and more preferably in the range from 65A to 96A, determined by DIN ISO 48-4:2021-02 (average value; indentation of 3s) using samples that were tempered after preparation at 100 °C for 20 h. The bulk density of the foam beads used is preferably in the range from 30 to 250 kg/m³.

Expanded thermoplastic polyurethane beads according to the present invention belong to the group of particle foams, which are also referred to as foamed pellets (or bead foams, particle foam, expanded thermoplastic elastomer particles or expanded thermoplastic polyurethane beads). Particle foams and moldings (also referred to as molded article) made therefrom, based on thermoplastic polyurethanes or other thermoplastic elastomers, are known (for example WO 94/20568A1 , WO 2007/082838 A1 , WO2017/030835 A1 , WO 2013/153190 A1 , WO 2010/010010 A1) and can be used in many ways.

A foamed pellet or also a particle foam or bead foam in the sense of the present invention refers to a foam in the form of a particle, the average length of the particles preferably being in the range of 1 to 10 mm. In the case of non-spherical, e.g., oval particles average length means the longest dimension by length, (determined by 3D evaluation of the granules, for example by means of dynamic image analysis with an optical measuring device named “PartAn 3D”, Microtrac).

The single foam granules according to the present invention preferably have an average mass in the range of 0.1 to 50 mg, preferable in the range between 0.5 and 45 mg. The average mass means in this context the arithmetic mean based on a sample size of 10 different particles wherein each particle is weighted three times.

The foamed pellets according to the invention usually have a bulk density of 30 g/l to 250 g/l, preferably 50 g/l to 200 g/l, more preferably 70 g/l to 180 g/l. The bulk density is measured analogously to DIN ISO 60:1999, wherein the determination of the above values in contrast to the standard, a vessel with 10 I volume is used instead of a vessel with 0.1 I volume, since especially for the foam particles with low density and large mass a measurement with only 0.1 I volume is too inaccurate.

The particle foam according to the present invention can optionally be optimized by additives such as for example dyes, process aids, nucleating agents or stabilizers. The additives may be added during the generation of the precursor of the particle foam or during the foaming step. A precursor is a polymer composition that is used as input material for foaming.

In another embodiment of the present invention, the particle foams can be coated.

In a preferred embodiment for the particle foam molding according to the invention expanded thermoplastic polyurethane beads of the same composition and the same average mass are used.

In a preferred embodiment the particle foam molding consists of expanded thermoplastic polyurethane beads. According to a further aspect, the present invention is also directed to the process as disclosed above, wherein the thermoplastic elastomer is a thermoplastic polyurethane.

In a preferred embodiment the dielectric loss factor of the expanded thermoplastic polyurethane beads of the particle foam molding at 27 MHz and 20°C is in the range from 0.06 to 0.15.

It is assumed that the dielectric loss factor of TPU equals the dielectric loss factor of foamed TPU. The dielectric loss factor can be measured for example with a dielectric material test fixture named Keysight. For this purpose, small and compact TPU plates have to be generated by injection molding and, afterwards, cut into pieces which can be placed in the dielectric test fixture.

According to the present invention, the fusing the expanded particles comprising a thermoplastic elastomer are fused by supplying energy at least partially through an electromagnetic field. The thermal energy which results from the stimulation of the thermoplastic elastomer is sufficient to result in the thermal joining of the foam beads.

Typically, the thermal joining of the foam beads is effected in a mold via high-frequency electromagnetic radiation, especially via microwaves. High-frequency is to be understood as referring to electromagnetic radiation having frequencies of not less than 100 MHz. The electromagnetic radiation used is generally in the frequency range between 100 MHz and 300 GHz. Preference is given to using microwaves in the frequency range between 0.5 and 100 GHz, more preferably 0.8 to 10 GHz and irradiation times between 0.1 to 15 minutes. The frequency range of the microwave is preferably aligned with the absorption behavior of the thermoplastic elastomer, or conversely the thermoplastic elastomer is selected on the strength of its absorption behavior in relation to the frequency range of the microwave appliance used.

The method of the present invention makes it possible to fuse the foam beads together across a very wide frequency range.

The energy may be supplied by electromagnetic induction. For this purpose, a dielectric molding-tool is placed in between at least two capacitor plates which generate at least one dielectric field. The expanded foam beads are loaded into the cavity of the molding tool and are heated by applying the dielectric field. As a result, the surface of the foam beads is partially molten and, therefore the beads become fused and form the molded part. To preserve the foam morphology and melt the bead surface only, the process is adapted in accordance with the used materials and the design of the molded article. In general, the energy input is controlled and adjusted by the applied voltage, the irradiation time, and the amount of material. Before the molded part can be removed from the molding tool, it must be stabilized and cooled down. The stabilization can be achieved by stopping the active heating or by means of an active cooling-procedure, such as for example described in EP3405322. Fusing by energetic radiation is generally carried out in the microwave-frequency range of 300 MHz - 300 GHz or in the radio-frequency range of 30 kHz - 300 MHz. Microwaves are preferably applied in the frequency range between 0.5 and 100 GHz, especially preferably in the range between 0.8 and 10 GHz and irradiation times between 0.1 and 15 min are used. Radio waves are preferably applied in the frequency range between 500 kHz and 100 MHz, especially preferably in the range between 1 MHz and 100 MHz and irradiation times between 0.1 and 30 min are used.

According to a further aspect, the present invention is also directed to the process as disclosed above, wherein in step (ii) the frequency of the electromagnetic field is in the range from 1 MHz to 100 MHz.

According to the present invention, expanded particles comprising a thermoplastic elastomer having a molecular weight Mw in the range of from 80 to 250 kg/mol are used. Preferably, the molecular weight Mw is in the range of from 100 to 200 kg/mol, in particular in the range of from 100 to 180 kg/mol.

Expanded particles comprising a thermoplastic elastomer and methods for the preparation thereof are in principle known from the state of the art. In particular expanded particles comprising a thermoplastic polyurethane are known from the state of the art. Typically, the molecular weight can be adjusted by methods known to the person skilled in the art, for example by adjusting the process parameters in the preparation process, the ratios of the starting materials used or also the reactivity of the starting materials used.

Thermoplastic polyurethanes usually are prepared using at least one polyisocyanate, at least one polyol and usually at least one chain extender. Suitable components for the preparation of thermoplastic polyurethanes are in principle known to the person skilled in the art.

Suitable isocyanates within the context of the present invention are in particular diisocyanates, in particular aliphatic or aromatic diisocyanates, more preferably aliphatic diisocyanates.

In addition, within the context of the present invention, pre-reacted products may be used as isocyanate components, in which some of the OH components are reacted with an isocyanate in a preceding reaction step. The products obtained are reacted with the remaining OH components in a subsequent step, the actual polymer reaction, thus forming the thermoplastic polyurethane.

Aliphatic diisocyanates typically used are customary aliphatic and/or cycloaliphatic diisocyanates. Suitable aromatic diisocyanates are also known to the person skilled in the art.

Mixtures can in principle also be used. Examples of mixtures are mixtures comprising at least one further methylene diphenyl diisocyanate besides methylene diphenyl 4,4’-diisocyanate. The term “methylene diphenyl diisocyanate” here means diphenylmethane 2,2’-, 2,4’- and/or 4,4’- diisocyanate or a mixture of two or three isomers. It is therefore possible to use as further isocyanate, for example, diphenylmethane 2,2’- or 2,4’-diisocyanate or a mixture of two or three isomers. In this embodiment, the polyisocyanate composition can also comprise other abovementioned polyisocyanates.

If further isocyanates are used, these are present in the isocyanate composition (IC) preferably at an amount in the range from 0.1 % to 20% by weight, further preferably in the range from 0.1 % to 10% by weight and particularly preferably at an amount in the range from 0.5% to 5% by weight.

Preferred examples of higher-functionality isocyanates are triisocyanates, for example triphenylmethane 4,4',4"-triisocyanate, and also the cyanurates of the aforementioned diisocyanates, and the oligomers obtainable by partial reaction of diisocyanates with water, for example the biurets of the aforementioned diisocyanates, and also oligomers obtainable by controlled reaction of semiblocked diisocyanates with polyols having an average of more than two and preferably three or more hydroxyl groups.

Organic isocyanates that can be used are aliphatic, cycloaliphatic, araliphatic and/or aromatic isocyanates.

Crosslinkers can additionally also be used, for example the previously mentioned higher-functionality polyisocyanates or polyols, or else other higher-functionality molecules having a plurality of isocyanate-reactive functional groups. It is likewise possible within the context of the present invention to achieve crosslinking of the products through an excess of the isocyanate groups used in proportion to the hydroxyl groups. Examples of higher-functionality isocyanates are triisocyanates, for example triphenylmethane 4,4',4"-triisocyanate and isocyanurates, and also the cyanurates of the aforementioned diisocyanates, and the oligomers obtainable by partial reaction of diisocyanates with water, for example the biurets of the aforementioned diisocyanates, and also oligomers obtainable by controlled reaction of semiblocked diisocyanates with polyols having an average of more than two and preferably three or more hydroxyl groups.

Here, within the context of the present invention, the amount of crosslinker, that is to say of higher-functionality isocyanates and higher-functionality polyols or higher-functionality chain extenders, is no greater than 3% by weight, preferably less than 1 % by weight, further preferably less than 0.5% by weight, based on the total mixture of the components.

The polyisocyanate composition may also comprise one or more solvents. Suitable solvents are known to those skilled in the art. Suitable examples are nonreactive solvents such as ethyl acetate, methyl ethyl ketone and hydrocarbons.

A polyol composition (PC) may be used according to the invention. According to the invention, the polyol composition (PC) may comprise at least one polyol. Suitable polyols are known in principle to those skilled in the art and described for example in "Kunststoffhandbuch [Plastics Handbook], volume 7, Polyurethane [Polyurethanes]”, Carl Hanser Verlag, 3rd edition 1993, chapter 3.1 . Particular preference is given to using, as polyol, polyesterols or polyetherols as polyols. It is likewise possible to use polycarbonates. Copolymers may also be used in the context of the present invention. Polyether polyols are particularly preferred. The number-average molecular weight of the polyols used according to the invention is preferably in the range from 500 to 5000 g/mol, by way of example in the range from 550 g/mol to 2000 g/mol, preferably in the range from 600 g/mol to 1500 g/mol, especially between 650 g/mol and 1000 g/mol. According to the present invention, the polyols used can be fossil based or non-fossil based.

Polyetherols, but also polyesterols, block copolymers and hybrid polyols such as for example poly(ester/amide), are suitable according to the invention. According to the invention, preferred polyetherols are polyethylene glycols, polypropylene glycols. Suitable polyols may also be selected from polyadipates, polycarbonates, polycarbonate diols and polycaprolactone.

In a further embodiment, the present invention accordingly relates to foamed pellets as described previously, wherein the polyol composition comprises a polyol selected from the group consisting of polyetherols, polyesterols, such as polycaprolactone polyols, and polycarbonate polyols.

Suitable polyols are for example those having ether and ester blocks, for example polycaprolactone having polyethylene oxide or polypropylene oxide end blocks, or else polyethers having polycaprolactone end blocks. According to the invention, preferred polyetherols are polyethylene glycols and polypropylene glycols. Suitable polyols are for example polytetramethylene gylcole or polytrimenthylene glycole. Polycaprolactone is also preferred. According to the present invention, also polyesterols may be used, in particular non fossil based polyesterols. Suitable polyesterols are for example based on succinic acid. Polyols based on castor oil or lignin based polyols may also be used.

It is also possible in accordance with the invention to use mixtures of different polyols. The poly- ols/the polyol composition used preferably have/has an average functionality of between 1 .8 and 2.3, preferably between 1 .9 and 2.2, in particular 2. The polyols used in accordance with the invention preferably have solely primary hydroxyl groups.

In an embodiment of the present invention, a polyol composition (PC) is used which comprises at least polytetrahydrofuran. According to the invention, the polyol composition may also comprise further polyols in addition to polytetrahydrofuran.

Further polyols that are suitable according to the invention are, for example, polyethers, but also polyesters, block copolymers and also hybrid polyols such as for example poly(ester/amide). Suitable block copolymers are for example those having ether and ester blocks, for example polycaprolactone having polyethylene oxide or polypropylene oxide end blocks, or else polyethers having polycaprolactone end blocks. According to the invention, preferred polyetherols are polyethylene glycols and polypropylene glycols. Polycaprolactone is also preferred as a further polyol.

According to the present invention, it is also possible to use polytetramethylengylcole or polytri- menthylenglycole which are non-fossil based or mixtures of fossil and non-fossil based polyols.

In a particularly preferred embodiment, the polytetrahydrofuran has a number-average molecular weight Mn in the range from 500 g/mol to 5000 g/mol, preferably in the range of from 500 g/mol to 2000 g/mol, further preferably in the range from 550 to 2000 g/mol, particularly preferably in the range from 650 to 1400 g/mol.

Within the context of the present invention, the composition of the polyol composition (PC) can vary within wide ranges. The polyol composition can also comprise mixtures of various polyols.

According to the invention, the polyol composition may also comprise a solvent. Suitable solvents are known erse to those skilled in the art.

When polytetrahydrofuran is used, the number-average molecular weight Mn of the polytetrahydrofuran is preferably in the range from 500 to 2000 g/mol. The number-average molecular weight Mn of the polytetrahydrofuran is further preferably within the range from 650 to 1400 g/mol.

In a further embodiment, the present invention also relates to foamed pellets as described previously, wherein the polyol composition comprises a polyol selected from the group consisting of polytetrahydrofurans having a number-average molecular weight Mn in the range from 500 g/mol to 5000 g/mol.

In a further embodiment, the present invention accordingly relates to foamed pellets as described previously, wherein the polyol composition comprises a polyol selected from the group consisting of polytetrahydrofurans having a number-average molecular weight Mn in the range from 500 g/mol to 2000 g/mol.

Mixtures of various polytetrahydrofurans can also be used in accordance with the invention, that is to say mixtures of polytetrahydrofurans having different molecular weights.

Preferred polyetherols according to the invention are polyethylene glycols, polypropylene glycols and polytetrahydrofurans, and also mixed polyetherols thereof. Mixtures of various polytetrahydrofurans differing in molecular weight may by way of example also be used according to the invention.

According to the invention, at least one chain extender (CE1 ) may be used. Suitable chain extenders are known per se to those skilled in the art. By way of example, chain extenders are compounds having two groups which are reactive towards isocyanate groups, in particular those having a molecular weight of less than 500 g/mol. Suitable chain extenders are for example diamines or diols. Diols are more preferred according to the invention. Within the scope of the present invention, mixtures of two or more chain extenders may also be used.

Suitable diols are known in principle to those skilled in the art. According to the invention, the diol preferably has a molecular weight of < 500 g/mol. According to the invention, aliphatic, arali- phatic, aromatic and/or cycloaliphatic diols having a molecular weight of 50 g/mol to 220 g/mol can be used here as chain extenders, for example. Preference is given to alkanediols having 2 to 10 carbon atoms in the alkylene radical, especially di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona- and/or decaalkylene glycols. For the present invention, particular preference is given to 1 ,2-ethylene glycol, propane-1 ,3-diol, butane-1 ,4-diol, pentane-1 ,5-diol, hexane-1 ,6-diol.

Suitable chain extenders (CE1 ) within the context of the present invention are also branched compounds such as 1 ,4-cyclohexanedimethanol, 2-butyl-2-ethylpropanediol, neopentyl glycol, 2,2,4-trimethylpentane-1 ,3-diol, pinacol, 2-ethylhexane-1 ,3-diol or cyclohexane-1 ,4-diol.

In a further embodiment, the present invention accordingly relates to foamed pellets as described previously, wherein the chain extender (CE1 ) is selected from the group consisting of propane-1 ,3-diol, ethane-1 ,2-diol, butane-1 ,4-diol, pentane-1 ,5-diol, hexane-1 ,6-diol and HQEE.

According to a further aspect, the present invention is also directed to the process as disclosed above, wherein the thermoplastic polyurethane is obtained or obtainable by reacting at least the components (a) to (c):

(a) a polyisocyanate composition (IC) comprising an isocyanate selected from the group consisting of methylene diphenyl diisocyanate, hexamethylene diisocyanate and pentameth- lyene diisocyanate;

(b) at least one chain extender (CE1),

(c) a polyol composition (PC).

The molecular weight of the thermoplastic polyurethane obtained may for example be adjusted by adjustment of the temperature applied in the preparation process. Typically, a lower temperature results in lower molecular weight. Furthermore, the use of a suitable catalyst and the amount of catalyst used may have an influence on the molecular weight of the thermoplastic polyurethane obtained. The molecular weight of the thermoplastic polyurethane obtained may also be adjusted by the ratio of the components used, in particular the ratio of NCO groups and the groups which are reactive towards isocyanate groups.

The quantitative ratios of the components used are preferably selected here such that a hard segment content in the range from 5% to 80% is obtained, preferably in the range of from 10% to 55%, in particular in the range of from 13% to 45%, more preferable in the range of from 15% to 35%. The hard segment content calculated according to the formula (I) unless otherwise noted: ⁿch.ainex tender ch.ai.nex tender diisocyanate)

HSC mtotal (I)

It has been found that thermoplastic polyurethanes having a molecular weight Mw in the range of from 80 to 250 kg/mol and a hard segment content of the thermoplastic polyurethane in the range of from 15% to 50% are particularly suitable for the preparation of molded bodies.

According to a further aspect, the present invention is also directed to the process as disclosed above, wherein the hard segment content of the thermoplastic polyurethane is in the range of from 15% to 50%, calculated according to the formula (I):

(I).

Furthermore, it has been found that the crystallinity of the thermoplastic elastomers may have an influence on the properties of the mold obtained. It has been found that thermoplastic elastomers, in particular thermoplastic polyurethanes having a low crystallinity are particularly suitable for the preparation of molded bodies. The crystallinity can be determined by DSC measurement according to DIN EN ISO 11357-3:2018 including a drying step within the measurement system of 10 minutes at 100 °C before starting the measurement from below 0 °C to 250 °C with a cooling rate of 20 K/min to the start temperature of the measurement and a heating rate of 10 K/min from the start temperature up to the 250°C.

The moldings can be produced by means of molding machines. For this purpose, the foamed particles are conveyed into the shaping tool manually or automated by using pressurized air. The shaping tool also referred to as mold or molding tool comprises two primary components, the injection mold-plate with the filling nozzles, and a counterpart-plate. To generate the molding part, both mold-plates are pressed together so that a cavity in the shape of the molding part is formed. The filling of the mold-cavity can be conducted either by crack filling method or by the pressure filling method.

The crack-filling method comprises the following steps:

(i’) injecting the expanded foam-particles into the mold-cavity without a backpressure of the counterpart-plate,

(ii’) fusing the particles while closing the plates of the mold mechanically,

(iii’) cool down the molding part and

(iv’) demold the produced part, wherein in step (i') a gap between the injection mold-plate and the counterpart-plate is adjusted which is also referred to as crack-height. The mold-cavity is filled with a predetermined amount of the expanded beads in step (i’). In step (ii’) the volume of the mold-cavity is reduced com- pared to step (i'), because the two parts of the molding tool are closed tightly and the intermediate gap is, thus, disappeared. This leads to a pressure increase within the mold-cavity. The expanded beads are thus pressed against one another and can therefore become fused to give the molding.

The degree of compression is one important parameter to control the fusion-quality of the molding. The degree of compression is calculated by dividing the dosage volume per cycle through the volume of the mold cavity adjusted in step (ii’), wherein the dosage volume per cycle is given by the dosage weight per cycle divided through the bulk density of the foamed beads.

In one embodiment according to the present invention the degree of compression is in the range from 1 .7 to 2.3. Preferably, the degree of compression at the crack-filling method is lower than 2.

The pressure filling method comprises the following steps:

(i’) injecting the expanded foam-particles into the mold-cavity by pneumatic pressure while compressing both plates of the mold tightly together,

(ii’) fusing the particles,

(iii’) cool down the molding part, (iv’) demold the produced part.

Since the exerted injection pressure in step (i’) is ceased in step (ii’) the inserted foam beads may further expand and as a result be pressed against one and another and, therefore, become fused and give the molding.

The fusing in step (ii’) can be induced by means of at least one electromagnetic field, independently of the chosen loading method.

According to a further embodiment, the present invention therefore is also directed to a process as disclosed above, wherein in step (i) crack-filling method is used.

The expanded particles comprising a thermoplastic elastomer having a molecular weight Mw in the range of from 80 to 250 kg/mol can be molded without using additional additives which can be stimulated through an electromagnetic field, in particular additives which can be stimulated through an electromagnetic field to increase the temperature within the mold. Preferably, no additives are used in the process according to the present invention which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold.

According to a further aspect, the present invention is also directed to the process as disclosed above, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold. According to a further aspect, the present invention is also directed to the use of expanded particles comprising a thermoplastic elastomer for the preparation of a molded body by fusing the particles by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 80 to 250 kg/mol.

According to a further aspect, the present invention is also directed to a molded body obtainable or obtained by a process as disclosed above.

Owing to their elastomeric properties, the bead foams of the present invention are useful for applications in the sports, footwear and packaging sectors, for example as safety footwear or as packaging for electronic components or instruments.

The invention additionally provides for the use of inventive foamed pellets for the production of a molded body for shoe intermediate soles, shoe insoles, shoe combisoles, bicycle saddles, bicycle tires, damping elements, cushioning, mattresses, underlays, grips, protective films, in components in automobile interiors and exteriors, in balls and sports equipment or as floor covering, especially for sports surfaces, track and field surfaces, sports halls, children's playgrounds and pathways. The invention additionally provides for the use of inventive foamed pellets for the production of consumer goods or industrial goods, parts in the automotive sector or packaging.

Preference is given to using inventive foamed pellets for the production of a molded body for shoe intermediate soles, shoe insoles, shoe combisoles or a cushioning element for shoes. Here, the shoe is preferably an outdoor shoe, sports shoe, sandals, boot or safety shoe, particularly preferably a sports shoe.

According to a further aspect, the present invention is also directed to the use of the molded body obtained or obtainable according to the process as disclosed above in shoe soles, part of shoe soles, shoe intermediate soles, shoe insoles, damping elements, cushioning elements, underlays, grips, flooring, mattresses, sporting goods, bicycle saddles, tires and in automotive interiors and exteriors.

Further embodiments of the present invention can be found in the claims and the examples. It will be appreciated that the features of the subject matter/processes/uses according to the invention that are mentioned above and elucidated below are usable not only in the combination specified in each case but also in other combinations without departing from the scope of the invention. For example, the combination of a preferred feature with a particularly preferred feature or of a feature not characterized further with a particularly preferred feature etc. is thus also encompassed implicitly even if this combination is not mentioned explicitly.

The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In par- ticular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The process of any one of embodiments 1 to 4", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The process of any one of embodiments 1 , 2, 3 and 4". Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention

Illustrative embodiments of the present invention are listed below, but these do not restrict the present invention. In particular, the present invention also encompasses those embodiments which result from the dependency references and hence combinations specified hereinafter.

1 . Process for the preparation of a molded body comprising expanded particles comprising a thermoplastic elastomer, comprising the steps of

(ii) fusing the expanded particles comprising a thermoplastic elastomer by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 50 to 250 kg/mol determined by means of gel permeation chromatography.

2. The process according to embodiment 1 , wherein in step (ii) the frequency of the electromagnetic field is in the range from 1 MHz to 100 MHz.

3. The process according to embodiment 1 or 2, wherein in step (i), the crack-filling method is used.

4. The process according to any one of embodiments 1 to 3, wherein the thermoplastic elastomer is a thermoplastic polyurethane.

5. The process according to any one of embodiments 1 to 4, wherein the hard segment content of the thermoplastic polyurethane is in the range of from 15% to 50%, calculated according to the formula (I):

(I).

6. The process according to any one of embodiments 1 to 5, wherein the thermoplastic polyurethane is obtained or obtainable by reacting at least the components (a) to (c): (a) a polyisocyanate composition (IC) comprising an isocyanate selected from the group consisting of methylene diphenyl diisocyanate, hexamethylene diisocyanate and pentamethlyene diisocyanate;

(b) at least one chain extender (CE1 ),

(c) a polyol composition (PC).

7. The process according to any one of embodiments 1 to 6, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold.

8. Use of expanded particles comprising a thermoplastic elastomer for the preparation of a molded body by fusing the particles by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 50 to 250 kg/mol.

9. Molded body obtainable or obtained by a process according to any one of embodiments 1 to 7.

10. Use of the molded body obtained or obtainable according to the process according to any one of embodiments 1 to 7 in shoe soles, part of shoe soles, shoe intermediate soles, shoe insoles, damping elements, cushioning elements, underlays, grips, flooring, mattresses, sporting goods, bicycle saddles, tires and in automotive interiors and exteriors.

11. Molded body comprising expanded particles comprising a thermoplastic elastomer obtainable or obtained by a process comprising the steps of

12. The molded body according to embodiment 11 , wherein in step (ii) the frequency of the electromagnetic field is in the range from 1 MHz to 100 MHz.

13. The molded body according to embodiment 11 or 12, wherein in step (i), the crack-filling method is used.

14. The molded body according to any one of embodiments 11 to 13, wherein the thermoplastic elastomer is a thermoplastic polyurethane. The molded body according to any one of embodiments 11 to 14, wherein the hard segment content of the thermoplastic polyurethane is in the range of from 15% to 50%, calculated according to the formula (I): nch.ainextender chainextender T diisocyanate)

HSC mtotal

(I). The molded body according to any one of embodiments 11 to 15, wherein the thermoplastic polyurethane is obtained or obtainable by reacting at least the components (a) to (c):

(a) a polyisocyanate composition (IC) comprising an isocyanate selected from the group consisting of methylene diphenyl diisocyanate, hexamethylene diisocyanate and pentamethlyene diisocyanate;

(b) at least one chain extender (CE1 ),

(c) a polyol composition (PC). The molded body according to any one of embodiments 11 to 16, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold. Process for the preparation of a molded body comprising expanded particles comprising a thermoplastic polyurethane, comprising the steps of

(i) loading the expanded particles comprising a thermoplastic polyurethane into a mold,

(ii) fusing the expanded particles comprising a thermoplastic polyurethane by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic polyurethane has a molecular weight Mw in the range of from 50 to 250 kg/mol determined by means of gel permeation chromatography. The process according to embodiment 18, wherein in step (ii) the frequency of the electromagnetic field is in the range from 1 MHz to 100 MHz. The process according to embodiment 18 or 19, wherein in step (i), the crack-filling method is used. The process according to any one of embodiments 18 to 20, wherein the hard segment content of the thermoplastic polyurethane is in the range of from 15% to 50%, calculated according to the formula (I): nch.ainextender chainextender T diisocyanate)

HSC mtotal (I).

22. The process according to any one of embodiments 18 to 21 , wherein the thermoplastic polyurethane is obtained or obtainable by reacting at least the components (a) to (c):

(b) at least one chain extender (CE1 ),

(c) a polyol composition (PC).

23. The process according to any one of embodiments 18 to 22, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold.

24. Process for the preparation of a molded body comprising expanded particles comprising a thermoplastic polyurethane, comprising the steps of

(ii) fusing the expanded particles comprising a thermoplastic polyurethane by supplying energy at least partially through an electromagnetic field with a frequency of the electromagnetic field in the range from 1 MHz to 100 MHz, wherein the thermoplastic polyurethane has a molecular weight Mw in the range of from 50 to 250 kg/mol determined by means of gel permeation chromatography, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold.

25. Process for the preparation of a molded body comprising expanded particles comprising a thermoplastic elastomer, comprising the steps of

(ii) fusing the expanded particles comprising a thermoplastic elastomer by supplying energy at least partially through an electromagnetic field with a frequency of the electromagnetic field in the range from 1 MHz to 100 MHz, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 50 to 250 kg/mol determined by means of gel permeation chromatography, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold. 26. Molded body obtainable or obtained by a process according to any one of embodiments 24 and 25.

27. Use of the molded body obtained or obtainable according to the process according to any one of embodiments 24 to 25 in shoe soles, part of shoe soles, shoe intermediate soles, shoe insoles, damping elements, cushioning elements, underlays, grips, flooring, mattresses, sporting goods, bicycle saddles, tires and in automotive interiors and exteriors.

28. Process for the preparation of a molded body comprising expanded particles comprising a thermoplastic elastomer, comprising the steps of

(ii) fusing the expanded particles comprising a thermoplastic elastomer by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 80 to 250 kg/mol determined by means of gel permeation chromatography.

29. The process according to embodiment 28, wherein in step (ii) the frequency of the electromagnetic field is in the range from 1 MHz to 100 MHz.

30. The process according to embodiment 28 or 29, wherein in step (i), the crack-filling method is used.

31 . The process according to any one of embodiments 28 to 30, wherein the thermoplastic elastomer is a thermoplastic polyurethane.

32. The process according to any one of embodiments 28 to 31 , wherein the hard segment content of the thermoplastic polyurethane is in the range of from 15% to 50%, calculated according to the formula (I):

(I).

33. The process according to any one of embodiments 28 to 32, wherein the thermoplastic polyurethane is obtained or obtainable by reacting at least the components (a) to (c):

(b) at least one chain extender (CE1 ),

(c) a polyol composition (PC). 34. The process according to any one of embodiments 28 to 33, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold.

35. Use of expanded particles comprising a thermoplastic elastomer for the preparation of a molded body by fusing the particles by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 80 to 250 kg/mol.

36. Molded body obtainable or obtained by a process according to any one of embodiments 28 to 34.

37. Use of the molded body obtained or obtainable according to the process according to any one of embodiments 28 to 34 in shoe soles, part of shoe soles, shoe intermediate soles, shoe insoles, damping elements, cushioning elements, underlays, grips, flooring, mattresses, sporting goods, bicycle saddles, tires and in automotive interiors and exteriors.

38. Molded body comprising expanded particles comprising a thermoplastic elastomer obtainable or obtained by a process comprising the steps of

39. The molded body according to embodiment 38, wherein in step (ii) the frequency of the electromagnetic field is in the range from 1 MHz to 100 MHz.

40. The molded body according to embodiment 38 or 39, wherein in step (i), the crack-filling method is used.

41 . The molded body according to any one of embodiments 38 to 40, wherein the thermoplastic elastomer is a thermoplastic polyurethane.

42. The molded body according to any one of embodiments 38 to 41 , wherein the hard segment content of the thermoplastic polyurethane is in the range of from 15% to 50%, calculated according to the formula (I): (I). The molded body according to any one of embodiments 38 to 42, wherein the thermoplastic polyurethane is obtained or obtainable by reacting at least the components (a) to (c):

(b) at least one chain extender (CE1 ),

(c) a polyol composition (PC). The molded body according to any one of embodiments 38 to 43, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold. Process for the preparation of a molded body comprising expanded particles comprising a thermoplastic polyurethane, comprising the steps of

(ii) fusing the expanded particles comprising a thermoplastic polyurethane by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic polyurethane has a molecular weight Mw in the range of from 80 to 250 kg/mol determined by means of gel permeation chromatography. The process according to embodiment 45, wherein in step (ii) the frequency of the electromagnetic field is in the range from 1 MHz to 100 MHz. The process according to embodiment 45 or 46, wherein in step (i), the crack-filling method is used. The process according to any one of embodiments 45 to 47, wherein the hard segment content of the thermoplastic polyurethane is in the range of from 15% to 50%, calculated according to the formula (I):

(I). The process according to any one of embodiments 45 to 48, wherein the thermoplastic polyurethane is obtained or obtainable by reacting at least the components (a) to (c): (a) a polyisocyanate composition (IC) comprising an isocyanate selected from the group consisting of methylene diphenyl diisocyanate, hexamethylene diisocyanate and pentamethlyene diisocyanate;

(b) at least one chain extender (CE1 ),

(c) a polyol composition (PC).

50. The process according to any one of embodiments 45 to 49, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold.

51 . Process for the preparation of a molded body comprising expanded particles comprising a thermoplastic polyurethane, comprising the steps of

(ii) fusing the expanded particles comprising a thermoplastic polyurethane by supplying energy at least partially through an electromagnetic field with a frequency of the electromagnetic field in the range from 1 MHz to 100 MHz, wherein the thermoplastic polyurethane has a molecular weight Mw in the range of from 80 to 250 kg/mol determined by means of gel permeation chromatography, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold.

52. Process for the preparation of a molded body comprising expanded particles comprising a thermoplastic elastomer, comprising the steps of

(ii) fusing the expanded particles comprising a thermoplastic elastomer by supplying energy at least partially through an electromagnetic field with a frequency of the electromagnetic field in the range from 1 MHz to 100 MHz, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 80 to 250 kg/mol determined by means of gel permeation chromatography, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold.

53. Molded body obtainable or obtained by a process according to any one of embodiments 51 and 52.

54. Use of the molded body obtained or obtainable according to the process according to any one of embodiments 51 to 52 in shoe soles, part of shoe soles, shoe intermediate soles, shoe insoles, damping elements, cushioning elements, underlays, grips, flooring, mattresses, sporting goods, bicycle saddles, tires and in automotive interiors and exteriors.

The invention is further described by examples. The examples relate to practical and in some cases preferred embodiments of the invention that do not limit the scope of the invention.

EXAMPLES

1 . Preparation of TPU

The preparation of the TPU to prepare the eTPU and afterwards mold it using an electromagnetic field was done using a twin-screw extruder ZSK 58MC of the company Coperion. The length of the twin screw extruder was 48D. After the twin screw extruder, a melt pump, a melt filter, and an underwater cutting system were located within the mentioned sequence. The melt was cut into single compact particles of 40 mg using the underwater pelletizing system and the particles dried at 40 - 90 °C using a heated fluidized bed.

The polyol, the isocyanate as well as the chain extender were added in the first barrel section of the twin screw extruder, the further additives in barrel section 8 out of 12. The used TPU recipe is shown in Table X1 .

The barrel temperature was set to 180 - 230 °C while the resulting melt temperature was in the range of 210 - 230 °C at a screw speed of 180 to 240 rpm. The overall throughput during the TPU production was 200 kg/h. TPU 1 was prepared at the lower range of the barrel and melt temperature with less mixing quality while TPU 2 was prepared at the upper level of the temperature range given above and an improved mixing quality to achieve different molecular weight (Mw) materials.

As a comparative example, TPU3 was prepared.

Table X1 : Recipe used for TPU production 2.1 Foaming of TPU 1 and TPU 2

The TPU 1 and TPU 2 were foamed according to W02013/153190 using a twin-screw extruder ZE40 from company Krauss Maffei Berstorff with a length of 42D. After the twin screw extruder, a melt pump, a starting valve including melt filter, and an underwater pelletizing system were in the mentioned sequence.

Before use, both TPUs were dried at 80 °C for 3h to ensure a maximum humidity of 0.02 wt.%.

The dried TPUs were dosed by a hopper into the first segment of the twin screw extruder and after being in the molten stage, CO2 and N2 were injected into the melt by separate injection units. The melt blowing agent mixture was homogenized during the rest of the extruder length. After the extruder, the melt pump pressed the homogeneous TPU blowing agent mixture through the melt filter and the die plate of the underwater cutting system. Within the water box of the underwater cutting system, the TPU melt blowing agent mixture was cut into single particles which expanded in the water pipe and were separated from the water in a spin drier at the end.

The overall throughput of the twin screw extruder was set to 40 kg/h while the amount of CO2 was set to 2.0 wt.% compared to the throughput of the TPU and the N2 was set to 0.2 wt.% compared to the throughput of the used TPU.

The extruder temperature was set from 170 to 220 °C while the water within the pipe of the underwater granulation system was set to 40 °C and 15 bar.

From the resulting beads, the bulk density as well as the molecular weight (Mw) were measured (Table X2). The bulk density is measured analogously to DIN ISO 60:1999, wherein the determination of the above values in contrast to the standard, a vessel with 10 I volume is used instead of a vessel with 0.1 I volume, since especially for the foam particles with low density and large mass a measurement with only 0.1 I volume is too inaccurate.

2.2 Foaming of TPU 3

The experiment was carried out with a degree of filling of the vessel of 80%. 100 parts by weight of the pellets (corresponding to 26,2% by weight, based on the total suspension without blowing agent), 279 parts by weight of water (corresponding to 73% by weight based on the total suspension without blowing agent), 3 parts by weight of a surface-active substance (Disponil LDBS 25 EVO, corresponding to 0,8% by weight, based on the total suspension without blowing agent) and the appropriate amount of n-butane as blowing agent (30% based on the amount of pellets used) were heated while stirring. Nitrogen was then injected at a temperature of the liquid phase of 50°C (3% based on the amount of pellets used). Depressurization was subsequently carried out via a depressurization apparatus after a holding time (HT) and attaining the impregnation temperature (I MT) and its corresponding impregnation pressure (IMP). The beads are cooled down by the water present in the depressurization apparatus. After removal of the suspension aid (soap) and drying, the bulk density (BD) of the resulting particles is measured. The beads obtained for TPU3 were difficult to dry had an uneven undulating surface.

Table X2: Measured bulk density and molecular weight of the 3 examples and the comparison example.

3. Molding with electromagnetic field

All examples and the comparison example were molded using the Wave Foamer C from company Kurtz at a frequency of 27.14 MHz of the electromagnetic field (radio frequency molding). The mold was prepared out of polyethyleneterephtalate with a length and width of 200 mm each and a height of 10 mm.

For molding, the cavity was opened and the required amount of material was homogeneously placed by hand into the one part of the open mold. Afterwards, the mold was closed to a height of 10 mm and the molding process started. The used amount of eTPU as well as the corresponding degree of compaction and the used molding conditions are shown in Table X3.

T able X3: Amount of material of the different eTPUs as well as the corresponding degree of compaction and the used molding conditions for radio frequency molding For eTPU3, RF molding did not result in stable moldings. Only several particles were joined and it was not possible to prepare plates for further testing.

As further comparison to standard molding technique with steam, eTPU 1 and eTPU 2 were also molded using an Energy Foamer from Kurtz. The respective molding parameters are shown in Table X4. As mold, the same dimensions as for RF molding with 200 mm in length and width was used. The final height of the plate was 10 mm while the mold was opened to a height of 24 mm during filling. Table X4: Molding parameters for eTPU 1 and eTPU 2 as comparison examples using state of the art steam molding.

Out of the resulting plates from radio frequency molding and steam molding test specimen were punched out using a swivel arm punch. The dimension of the test specimen was 150 mm in length, 25 mm in width and 10 mm in thickness (according to ASTM D5035 from 2015). These samples were tested by standard tensile test as it provides the best information on molding quality. Using the same material, the higher the value in elongation at break, the better the molding quality as the better the single beads are connected to each other. The test specimens were put into the test machinery from Zwick (Z020 Allround Line) and the test was run with a speed of 100 mm/min. The elongation was measured using the long- throw transducer of the machinery until the specimen breaks. The resulting values of the elongation at break for the different Examples and Comparison examples are shown in Table X5.

Table X5: Elongation at break values for the different Examples and comparison examples.

Literature cited

WO2014/198779 A1

WO20 15/052265 A1

DE102013110242 A1

EP3698949 A1

W02017/125410 A1

EP3808522 A1

WO 2017/125410 A1

WO 2001/64414 A1

WO 2019/162172 A1

DE 102013 012 515 A1

WO 94/20568A1

WO 2007/082838 A1

WO2017/030835 A1

WO 2013/153190 A1

WO 2010/010010 A1

EP3405322A1

Kunststoffhandbuch [Plastics Handbook], volume 7, Polyurethane [Polyurethanes]”, Carl Hanser

Verlag, 3rd edition 1993, chapter 3.1

Claims

2. The process according to claim 1 , wherein in step (ii) the frequency of the electromagnetic field is in the range from 1 MHz to 100 MHz.

3. The process according to claim 1 or 2, wherein in step (i), the crack-filling method is used.

4. The process according to any one of claims 1 to 3, wherein the thermoplastic elastomer is a thermoplastic polyurethane.

5. The process according to any one of claims 1 to 4, wherein the hard segment content of the thermoplastic polyurethane is in the range of from 15% to 50%, calculated according to the formula (I):

6. The process according to any one of claims 1 to 5, wherein the thermoplastic polyurethane is obtained or obtainable by reacting at least the components (a) to (c):

(b) at least one chain extender (CE1 ),

(c) a polyol composition (PC).

7. The process according to any one of claims 1 to 6, wherein no additives are added in step (i) or (ii) which can be stimulated through an electromagnetic field in a way which results in a rise of temperature in the mold. Use of expanded particles comprising a thermoplastic elastomer for the preparation of a molded body by fusing the particles by supplying energy at least partially through an electromagnetic field, wherein the thermoplastic elastomer has a molecular weight Mw in the range of from 50 to 250 kg/mol. Molded body obtainable or obtained by a process according to any one of claims 1 to 7. Use of the molded body obtained or obtainable according to the process according to any one of claims 1 to 7 in shoe soles, part of shoe soles, shoe intermediate soles, shoe in- soles, damping elements, cushioning elements, underlays, grips, flooring, mattresses, sporting goods, bicycle saddles, tires and in automotive interiors and exteriors.