CN121443663A

CN121443663A - Storage-stable coated particles and their preparation

Info

Publication number: CN121443663A
Application number: CN202480043403.6A
Authority: CN
Inventors: U·利希特; A·M·克里斯塔多罗; E·波瑟尔特; J·P·迪尔森; V·福格尔桑; M·瓦罗; L·葛林格
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2023-06-28
Filing date: 2024-06-19
Publication date: 2026-01-30
Also published as: WO2025002949A1; TW202513634A

Abstract

本发明涉及一种用于制备可模塑热塑性颗粒泡沫的储存稳定的涂覆颗粒的方法，该方法包括以下步骤：a1)使该颗粒与聚氨酯水分散体接触，该聚氨酯具有至少第一玻璃化转变温度T_g1 _g1和第二玻璃化转变温度T_g2 _g2，其中T_g1 _g1低于0℃且T_g2 _g2高于25℃，产生至少部分涂覆的颗粒；以及a2)干燥该涂覆颗粒。本发明进一步涉及一种用于制备储存稳定的至少部分涂覆的颗粒的成型体的方法及其成型体。This invention relates to a method for preparing storage-stable coated particles of moldable thermoplastic granular foam, the method comprising the steps of: a1) contacting the particles with an aqueous polyurethane dispersion having at least a first glass transition temperature T _g1 _g 1 and a second glass transition temperature T_g2 _{g2} , wherein T _g1 _g 1 is below 0°C and T_g2 _g2 is above 25°C, to produce at least partially coated particles; and a2) drying the coated particles. The invention further relates to a method for preparing a molded article of storage-stable, at least partially coated particles, and the molded article thereof.

Description

Storage-stable coated particles and preparation thereof

Description of the invention

The invention relates to a process for preparing storage-stable coated particles of a moldable thermoplastic particle foam, comprising the steps of a ₁) contacting the particles with an aqueous polyurethane dispersion, the polyurethane having at least a first glass transition temperature T _g1 and a second glass transition temperature T _g2, wherein T _g1 is below 0 ℃ and T _g2 is above 25 ℃, resulting in at least partially coated particles, and a ₂) drying the coated particles. The invention further relates to a method for producing a molded body of storage-stable at least partially coated particles and to the molded body thereof.

Moldable thermoplastic particle foam, including thermoplastic elastomer particle foam, is used, for example, to produce any solid foam such as for exercise mats, body protectors, lining elements in automotive construction, sound and vibration dampers, packaging, or shoe soles.

Typically, the mould is filled with foam particles, which are then melted on their surface by the action of heat and in this way connected to each other to form a particle foam. Thus, in addition to simple products, complex semifinished products or molded parts with undercuts can also be produced.

Moldable thermoplastic particle foams are known in the art and are described, for example, in Robin Britton (authors), update on Moldable Particle Foam Technology, rapra technology Ltd, 2009. Expanded thermoplastic elastomers, in particular expanded thermoplastic polyesters (E-TPC), expanded thermoplastic copolyamides (E-TPA), expanded thermoplastic polyurethanes (E-TPU), represent specific moldable thermoplastic particle foams.

Expanded thermoplastic elastomers are known in the art. For example, WO 2018/082984 A1 describes a particulate foam based on an expanded thermoplastic elastomer. WO 2008/087078 A1 describes a mixed system consisting of a foamed thermoplastic elastomer and polyurethane.

An exemplary thermoplastic polymer is an expanded thermoplastic polyurethane (E-TPU), which is commercially available, for example, from Basoff corporation under the designation INFINERGY ^®. The E-TPU particles represent a largely to completely closed-cell, particulate foam. Thermoplastic polyurethane (e.g., elastollan ^®) is expanded to produce a particulate foam and can be processed on standard molding machines. The standard E-TPU grade also absorbs only small amounts of water due to its closed particle surface and the chemistry of the TPU used. Similar to the TPU on which it is based, it is also characterized by high elongation at break, tensile strength and abrasion resistance, as well as good chemical resistance.

Rapid prototyping of 3D objects made from expanded thermoplastic elastomers is currently not easy to achieve. Typically, isocyanate-containing binders are used to bind the particles or water vapor to a suitable machine such as a steam box molding. Both methods are not readily available for health safety reasons, energy costs or due to lack of availability of suitable machinery (vapor chamber molding). Furthermore, the use of steam only allows molding the same kind of particles, whereas the use of a coating or water-based binder on the E-TPU particles may allow bonding E-TPU particles of different kinds (glass transition temperature, melting point) and sizes, but also bonding different TPU or even different particle foams such as E-TPS, E-PS, E-PP, E-TPA, E-TPC, E-TPO, etc. different mixtures. The application of the coating also allows for the adjustment of mechanical properties and suitability by incorporating additives such as, for example, pigments or dyes, flame retardants or antistatic agents directly onto the particle surface. The filler for example allows to increase the rigidity of the final part, while the use of additives which can be excited for example by an electromagnetic field allows the moldability of the coating and thus reduces the energy required for molding.

Useful as additives are pigments, dyes, odorants, fillers, bio-based and/or biodegradable additives, UV stabilizers, heat stabilizers, flame retardants such as expandable graphite, additives that create antistatic properties, electrical conductivity, additives that reduce dirt absorption, anti-slip additives, antimicrobial additives, waxes, cross-linking agents, surface-functionalized fillers, foamable additives such as Expancell, additives that can be irradiated by electromagnetic fields and/or radio frequency and/or microwaves.

WO 2022/223438 A1 describes different water-based binders for coating particles which can be shaped into the shape of the 3D part.

US 6,616,797 B1 describes the formation of adhesive bonds by a method comprising applying a dispersion containing a polyurethane having structural units of formula (I) to a surface. The dispersion is first applied to a surface to form a coating. The coating is dried to give a substantially anhydrous coating. The dried coating is then thermally activated. The adhesive bond is formed by bonding the heat activated coating to itself or to another surface. However, particle coating is not described.

WO 2012/13506 A1 describes the use of an aqueous polyurethane dispersion adhesive for producing a biodisintegratable composite film having at least two substrates bonded to each other using the aqueous polyurethane dispersion adhesive, wherein at least one of the substrates is a biodisintegratable polymer film. At least 60% by weight of the polyurethane is composed of a diisocyanate, a polyester diol and at least one difunctional carboxylic acid selected from the group consisting of dihydroxycarboxylic acids and diaminocarboxylic acids.

WO 2005/003247 A1 relates to a method for bonding substrates having different surface energies. The adhesive used for bonding consists of at least 15% by weight of polyurethane (uncounting water or other organic solvent having a boiling point below 150 ℃ at 1 bar), is applied to a substrate having a lower surface energy and bonds the resulting adhesive coated substrate to a substrate having a higher surface energy.

WO2021/7249749 describes the recycling of bonded articles, including TPU-foam substrates, by using an aqueous polyurethane dispersion of defined molecular weight as binder. There is no mention that the expanded particles are coated.

WO 2024/083787 A1 describes a process for preparing storage-stable coated particles of a moldable thermoplastic particle foam, wherein the particles are at least partially coated with an aqueous polyurethane dispersion having a K value in the range from above 50 to below 100, preferably from 55 to 95, according to DIN EN ISO 1628-1 2021.

US 10,669,447 B2 describes a method for producing a coating on a substrate by curing a two-component coating composition to produce a crosslinked coating that is no longer thermoplastic.

However, even more improved stability is required for storage and transport of coated particles at higher temperatures. During transportation in the hot season, for example during transportation in a container that can be heated to 60 ℃, no caking should also be observed in storage.

It is therefore an object of the present invention to provide a process for preparing storage-stable coated particles.

This object is achieved by a process for preparing storage-stable coated particles of a moldable thermoplastic particle foam, comprising the steps of:

a ₁) contacting the particles with an aqueous polyurethane dispersion, the polyurethane having at least a first glass transition temperature T _g1 and a second glass transition temperature T _g2, wherein T _g1 is below 0 ℃ and T _g2 is above 25 ℃, resulting in at least partially coated particles;

a ₂) drying the coated particles.

Another aspect of the invention is a method for producing a shaped body, comprising the steps of:

b ₁) according to the process of the invention for preparing storage-stable coated particles, particles of expanded thermoplastic elastomer are coated;

b ₂) shaping the granules obtained from step b ₁).

Another aspect of the invention is a storage stable at least partially coated particle of a moldable thermoplastic particle foam, wherein the coating is a dried aqueous polyurethane dispersion, and wherein the polyurethane has at least a first glass transition temperature T _g1 and a second glass transition temperature T _g2, wherein T _g1 is below 0 ℃ and T _g2 is above 25 ℃, which particles are preferably obtainable by the process for preparing storage stable coated particles according to the invention.

Another aspect of the invention is a shaped body comprising storage-stable at least partially coated particles according to the invention, which particles are preferably obtainable by the process according to the invention for the preparation of shaped bodies.

Surprisingly, it has been found that polyurethanes in aqueous polyurethane dispersions having at least two of the above glass transition temperatures can be used to achieve 3D parts without the need for steam. The coating allows to realize by hot pressing 3D parts with excellent mechanical values, which are comparable and even better than 3D parts manufactured by using standard steam chamber molding processes.

In particular, preferred dispersions for use in the process of the invention may have a high solids content (> 35%) but still exhibit low viscosity. This allows for easy application of the dispersion to the particles. The particles are uniformly coated with a clear coating that is non-tacky at room temperature. On the other hand, when the particles are heated under compression, such as in a hot pressing process, the coating melts and allows the beads to bridge when cooled. Only moderate heating is required.

Furthermore, the coated particles surprisingly show improved flow behaviour, which is a very important factor when the particles are stored for a long time, for example in an octabin, since in addition to the very interesting antistatic properties, clogging of the particles during storage can also cause unpleasant problems at the customer site.

The coating on the surface of the particles has the further additional advantage that particles of different sizes and chemical properties (e.g. E-TPU, E-TPS, E-PS, E-TPO, E-PP, E-PE, E-TPA, E-TPC) can be bonded together, since the bonding ability comes from the coating and not from melting of the walls of the particles. This has the advantage that particles with a high melting point can also be processed into 3D parts in a steam-free process at a temperature of, for example, 100 ℃.

A hot press can be used, which has the advantage that steam can be avoided and a low-temperature mould can be used. This results in energy savings and complexity reduction.

The additives can be mixed with the coating and placed directly onto the bead surface. Interesting additives are thermally conductive particles, antistatic particles, flame retardants, dyes, UV stabilizers, ferromagnetic particles, anti-caking agents, etc.

When using a water-redispersible dispersion, for example by exposing a 3D part to alkaline conditions under stirring, the particles in the 3D part (shaped body) coated with the polyurethane dispersion described herein can be decomposed.

In the realization of 3D parts, another material (e.g. textiles, precursors, thermoplastic films, metal parts, in-mold coatings) may be bonded to these particles in one step. This allows to realize a plurality of hybrid materials for different applications (sports (shoes) and leisure, automobile interiors, electronic applications, flooring materials).

Although not preferred, as described in EP 3 338 984 B1 for expanded beads, the coated particles can still be processed with standard steam chamber molding processes or other heating processes using high energy radiation to raise the coating temperature, so they are compatible with already existing customer equipment.

This process allows the realization of 3D parts with very complex geometries. The 3D part may still have empty spaces between the particles (allowing water to permeate) or may not have empty spaces between the beads, which is highly desirable for sole manufacturing.

The process of the present invention relates to the preparation of coated particles of a moldable thermoplastic particle foam. Such foams are known in the art (see, e.g., robin Britton (authors), update on Mouldable Particle Foam Technology, rapra technology Ltd, 2009). Preferably, the moldable thermoplastic particle foam is an expanded thermoplastic elastomer.

Surprisingly, it was found that an improved stability of the coated particles in storage and transport at higher temperatures (as demonstrated by the caking test used in the examples section) can be observed. Furthermore, no caking during storage was observed during transportation in the hot season.

Expanded thermoplastic elastomer particles are known in the art. Suitable thermoplastic elastomers are, for example, thermoplastic Polyurethanes (TPU), thermoplastic polyester elastomers (e.g., polyetheresters and polyesteresters) (TPC), thermoplastic copolyamides (e.g., polyether copolyamides) (TPA), thermoplastic Polyolefins (TPO) or thermoplastic styrene butadiene block copolymers (TPS). Foam particles based on Thermoplastic Polyurethane (TPU) are particularly preferred. Thus, preferably, the expanded thermoplastic elastomer is E-TPA, E-TPC or E-TPU, especially E-TPU.

Examples of methods for preparing expanded thermoplastic elastomer particles are described in WO 2008/087078 A1, WO 2018/082984 A1, US 10 005 218 B2 and WO 2007/082838 A1.

The same type of particles (chemical nature and/or size) may be used. Mixtures of different (foam) particles may also be used according to the invention.

In a preferred embodiment, the particles comprise at least two particles based on different polymers or different particle sizes. In the sense of the present invention, two or more foam particles refer to a mixture of different batches of loose foam particles, wherein the chemical nature and/or size of the batches are different.

In principle, all types of particles can be mixed, regardless of their thermal properties, such as melting point or glass transition.

In a preferred embodiment, different thermoplastic foam particles are mixed. More preferably, the foam particles comprise at least two thermoplastic foam particles selected from the group consisting of:

And is composed of styrene polymer foam particles, polyamide foam particles, thermoplastic elastomer foam particles, polyolefin foam particles, and mixtures thereof.

In general, all kinds of particles can be used, such as, for example, chopped foam parts or polymer foam waste based on thermosetting polymers, thermoplastic polymers or elastomeric polymers.

In a preferred embodiment, the additional material (liner) may be fused with the foam particles into a hybrid particle foam molded part. Preferably, the inner liner is selected from the group consisting of synthetic or natural fabrics, chopped fabrics, leather, paper, thermoplastic films, thermoplastic tapes, organic sheets, in-mold coatings, fibrous composite sheets, rubber crumb, wood sheets, thermoset films, plastic agglomerates, chopped foam materials, and mixtures thereof. The additional material may be virgin or recycled in nature. The liner may be fused with the foam particles in one step or in a separate processing step.

Preferably, the aqueous polymer dispersion used in the process of the invention has a solids content of at least 30 wt% based on the total weight of the dispersion, more preferably in the range of 35 to 60 wt% based on the total weight of the dispersion.

Preferably, the polyurethanes which belong to the aqueous polymer dispersions and are included in the at least partially coated particles and shaped bodies according to the invention have a viscosity of less than 300mPas at 23℃and preferably less than 200mPas at 23℃measured according to DIN EN ISO 3219-2:2021 at a shear rate of 23℃and 250s ^-1.

The polyurethanes of the aqueous polyurethane dispersion and contained in the at least partially coated particles and shaped bodies according to the invention have at least a first glass transition temperature T _g1 and a second glass transition temperature T _g2, wherein T _g1 is below 0 ℃ and T _g2 is above 25 ℃. Preferably, T _g1 is below-10 ℃. Preferably, T _g2 is higher than 40 ℃, more preferably higher than 50 ℃, even more preferably higher than 60 ℃. Typically, the polyurethane of the aqueous polyurethane dispersion has a T _g1 at-10 ℃ to-60 ℃ and a T _g2 at 60 ℃ to 90 ℃. Preferably, the polyurethane has exactly two T _g.

The glass transition temperature can be determined by differential scanning calorimetry according to DIN EN ISO 11357-2 (2014) as the so-called midpoint temperature. The glass transition temperature of the polymer in the polymer dispersion is the glass transition temperature at which the second heating profile (heating rate 20 ℃ per minute) is evaluated.

In general, the aqueous polyurethane dispersions used in the process of the present invention can be prepared by methods known in the art. An exemplary method is described in WO 2021/249749 A1.

Thus, the aqueous polyurethane dispersion comprises at least one polyurethane as a polymeric binder dispersed in water and optionally additives. Preferred additives are selected from the group consisting of ionic surfactants, nonionic surfactants, rheology modifiers (including thickeners), antiblocking additives, other aqueous dispersions, cross-linking agents, plasticizers, stabilizers against degradation, biocides, fillers, and defoamers. The polymeric binder is preferably in the form of a dispersion in water or in a mixture of predominantly water and a water-soluble organic solvent having a boiling point preferably below 150 ℃ (1 bar). Water is particularly preferred as the sole solvent.

In a further aspect of the invention the aqueous polyurethane dispersion comprises at least one additive selected from the group consisting of pigments, dyes, odorants, fillers, bio-based and/or biodegradable additives, UV stabilizers, heat stabilizers, flame retardants such as expandable graphite, additives that give antistatic properties, conductivity, additives that reduce soil absorption, anti-slip additives, antimicrobial additives, waxes, crosslinking agents, surface-functionalized fillers, foamable additives such as Expancell, additives that can be irradiated by electromagnetic and/or radio frequency and/or microwaves, ionic surfactants, nonionic surfactants, rheology modifiers, fillers, anti-blocking additives, other aqueous dispersions, crosslinking agents, plasticizers, stabilizers against hydrolytic degradation, defoamers and biocides.

Preferred other dispersions are those described in WO 2022/223438 A1.

The polyurethane dispersion used in the process according to the invention and included in the at least partially coated particles and shaped bodies according to the invention comprises at least one polyurethane. Suitable polyurethanes can in principle be obtained by reacting at least one polyisocyanate with at least one compound having at least two groups reactive towards isocyanate groups, using the specific requirements described below, in order to obtain a polyurethane having at least two T _g as described above.

Thus, the polyurethane of the aqueous polyurethane dispersion may be prepared from:

a) At least one organic diisocyanate selected from the group consisting of diisocyanates of the formula X (NCO) ₂, wherein X is an acyclic aliphatic hydrocarbon group having 4 to 15 carbon atoms, an alicyclic hydrocarbon group having 6 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 15 carbon atoms, or an araliphatic hydrocarbon group having 7 to 15 carbon atoms, wherein the amount of aromatic diisocyanate is less than 60mol-%, based on the total of all organic diisocyanates a);

b1 At least one dihydroxy compound having a molecular weight of 500g/mol to 5000g/mol and selected from the group consisting of polyester diol, polyether alcohol and polytetrahydrofuran;

b2 At least one dihydroxy compound selected from the group consisting of branched or unbranched acyclic diols having 2 to 8C atoms and cyclic diols having 3 to 8C atoms, the at least dihydroxy compound preferably having a molecular weight of 62g/mol to 200 g/mol;

c) At least one compound having at least one group which is reactive towards isocyanate groups and additionally carrying at least one ionic group or one group which can be converted into an ionic group, wherein the compound c) preferably contains a group selected from carboxylate and sulfonate groups,

D) Optionally, other compounds than a) to c).

The polyurethane dispersion, the at least partially coated particles and the shaped body according to the invention preferably comprise at least one polyurethane comprising at least one polyisocyanate and at least two polyols as described above in the form of a copolymer. The polyurethane dispersion and the at least partially coated particles and the shaped body according to the invention preferably comprise at least one polyurethane comprising at least one polyisocyanate and a diol component in the form of a copolymer, the at least one polyisocyanate and the diol component being a) from 10mol% to 90mol% based on the total amount of diols b 1) and b) from 90mol% to 10mol% based on the total amount of diols b 2). The polymeric polyol preferably has a number average molecular weight of about 500g/mol to 5000 g/mol.

The polyurethane is preferably synthesized to the extent of at least 35% by weight, more preferably at least 60% by weight and very preferably at least 80% by weight of at least one diisocyanate and at least two diols, based on the total weight of the monomers used to prepare the polyurethane. Suitable further synthesis components up to 100% by weight are, for example, the polyisocyanates having at least three NCO groups specified below and compounds which are different from the polymeric polyols and have at least two groups reactive toward isocyanate groups. These include, for example, non-polymeric diols, diamines, polymers different from polymeric polyols and having at least two active hydrogen atoms per molecule, compounds having two active hydrogen atoms per molecule and at least one ionizable/ionic group, and mixtures thereof.

Preferred polyurethanes are synthesized from:

a) At least one of the monomeric diisocyanates is used,

B) At least diols b 1) and b 2),

C) At least one monomer which, unlike monomers (a) and (b), has at least one isocyanate group or at least one group reactive towards isocyanate groups and additionally carries at least one hydrophilic group or potentially hydrophilic group,

D) Optionally at least one further compound different from the monomers (a) to (c), having at least two reactive groups selected from alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups, and

E) At least one monofunctional compound, different from the monomers (a) to (d), having one reactive group as an alcoholic hydroxyl group, a primary or secondary amino group or an isocyanate group.

Preferably, the polyurethane dispersion is an anionic polyurethane dispersion produced with little or no aromatic diisocyanate, for example less than 60mol%, based on the sum of all organic diisocyanates a). The anionic groups of the anionic polyurethane are preferably selected from carboxylate groups and sulfonate groups. The same applies to the polyurethanes included in the at least partially coated particles and shaped bodies according to the invention.

Component b) preferably consists of:

b1 10 to 90mol% of a glycol b 1) based on the total amount of component b),

B2 10mol% to 90mol% of a diol b 2), based on the total amount of component b).

The molar ratio of diol b 1) to monomer b 2) is more preferably from 1:5 to 5:1, more preferably from 1:2 to 2:1.

Mention may be made in particular of the monomers (a) of diisocyanates X (NCO) ₂, in which X is an acyclic aliphatic hydrocarbon radical having 4 to 15 carbon atoms, a cycloaliphatic or aromatic hydrocarbon radical having 6 to 15 carbon atoms or an araliphatic hydrocarbon radical having 7 to 15 carbon atoms. Examples of such diisocyanates include tetramethylene diisocyanate, hexamethylene Diisocyanate (HDI), dodecamethylene diisocyanate, 1, 4-diisocyanatocyclohexane, 1-isocyanato-3, 5-trimethyl-3-isocyanatomethylcyclohexane (IPDI), 2-bis (4-isocyanatocyclohexyl) propane, trimethylhexane diisocyanate, 1, 4-diisocyanatobenzene, 2, 4-diisocyanatotoluene, 2, 6-diisocyanatotoluene (TDI), 4 '-diisocyanatodiphenyl methane, 2,4' -diisocyanatodiphenyl methane, p-xylylene diisocyanate, tetramethylxylylene diisocyanate (TMXDI), isomers of bis (4-isocyanatocyclohexyl) methane (HMDI), such as trans/trans, cis/cis and cis/trans isomers, and mixtures of these compounds. Such diisocyanates are commercially available. Particularly preferably, the diisocyanate is selected from the group consisting of hexamethylene diisocyanate, 1-isocyanato-3, 5-trimethyl-3-isocyanatomethylcyclohexane, 2, 6-diisocyanatotoluene and tetramethylxylylene diisocyanate or mixtures thereof. A particularly important mixture of these isocyanates is a mixture of the corresponding structural isomers of diisocyanatotoluenes and diisocyanatopiphenylmethane, a mixture of 80mol% of 2, 4-diisocyanatotoluenes and 20mol% of 2, 6-diisocyanatotoluenes being particularly suitable. Furthermore, particularly advantageous are mixtures of aromatic isocyanates such as 2, 4-diisocyanatotoluene and/or 2, 6-diisocyanatotoluene with aliphatic or cycloaliphatic isocyanates such as hexamethylene diisocyanate or IPDI, in which case the preferred mixing molar ratio of aliphatic isocyanate to aromatic isocyanate is from 1:9 to 9:1, more particularly from 4:1 to 1:4. It is also preferred to use only aliphatic isocyanates.

The diol (b 1) may be, for example, a polyester polyol known from Ullmanns Enzyklopadie DER TECHNISCHEN CHEMIE, 4 th edition, volume 19, pages 62-65. It is preferable to use a polyester polyol obtained by reacting a dihydric alcohol with a dicarboxylic acid. Instead of the free polycarboxylic acids, the corresponding polycarboxylic anhydrides of lower alcohols or corresponding polycarboxylic esters or mixtures thereof can also be used to prepare the polyester polyols. The polycarboxylic acids may be aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic and may optionally be substituted, for example, by halogen atoms and/or unsaturated. Examples thereof include suberic acid, azelaic acid, phthalic acid, isophthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylene tetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, and dimerized fatty acids. Examples of suitable dihydric alcohols include ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, butane-1, 3-diol, butene-1, 4-diol, butyne-1, 4-diol, pentane-1, 5-diol, neopentyl glycol, bis (hydroxymethyl) cyclohexanes such as 1, 4-bis (hydroxymethyl) cyclohexane, 2-methylpropan-1, 3-diol, methylpentanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol and dibutylene glycol and polytetramethylene glycol in order to obtain crystallinity, preferred alcohols are alcohols of the formula HO- (CH ₂)_x -OH in which x is a number from 1 to 20, preferably an even number from 2 to 20.

The diol (b 1) may be polytetrahydrofuran. Suitable polytetrahydrofurans can be prepared by cationic polymerization of tetrahydrofuran in the presence of an acidic catalyst such as sulfuric acid or fluorosulfuric acid. Such preparation methods are known to the person skilled in the art.

The diol (b 1) may be a polyether diol. Polyether diols are obtainable in particular by polymerizing ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin with itself in the presence of, for example, BF3, or by subjecting these compounds, optionally in the form of mixtures or continuously, to an addition reaction with starter components containing reactive hydrogen atoms, such as alcohols or amines, examples being water, ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, 2-bis (4-hydroxyphenyl) propane and aniline. Particularly preferred are polyether diols having a molecular weight of 500 to 5000 and in particular 600 to 4500.

The compounds classified under b 1) include only those polyether diols which consist of ethylene oxide to the extent of less than 20% by weight, based on their total weight. The polyether diol having at least 20% by weight of incorporated ethylene oxide units is a hydrophilic polyether diol counted as monomer c).

The hardness and elastic modulus of the polyurethane can be improved by using not only the diol (b 1) but also a low molecular weight diol (b 2) having a molecular weight of about 60g/mol to less than 500g/mol, preferably 62g/mol to 200g/mol, as the diol (b).

The monomer (b 2) is at least one dihydroxy compound selected from the group consisting of branched or unbranched acyclic diols having 2 to 8C atoms, preferably 2 to 6 carbon atoms, or cyclic diols having 3 to 8C atoms, preferably 3 to 6 carbon atoms. Suitable diols b 2) include ethylene glycol, propane-1, 2-diol, propane-1, 3-diol, butane-1, 4-diol, butene-1, 4-diol, butyne-1, 4-diol, pentane-1, 5-diol, neopentyl glycol, hexane-1, 6-diol, 2-methylpropane-1, 3-diol, methylpentanediol, octane-1, 8-diol, bis (hydroxymethyl) cyclohexanes such as 1, 4-bis (hydroxymethyl) cyclohexane, further diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, dibutylene glycol. Preferred are acyclic dihydroxy compounds (b 2).

In order to make polyurethanes water-dispersible, they comprise, as synthesis component, monomers (c) which carry at least one isocyanate group or at least one group reactive towards isocyanate groups and, furthermore, at least one hydrophilic group or one group which can be converted into a hydrophilic group. Hereinafter, the term "hydrophilic group or potentially hydrophilic group" is abbreviated to "(potentially) hydrophilic group". The reaction rate of the (potentially) hydrophilic groups with the isocyanate is substantially lower than the functional groups of the monomers used to synthesize the polymer backbone. The fraction of components having (potentially) hydrophilic groups in the total amount of components (a) to (e) is generally such that the molar amount of (potentially) hydrophilic groups is 30mmol/kg to 1000mmol/kg, preferably 50mmol/kg to 500mmol/kg and more preferably 80mmol/kg to 300mmol/kg, based on the weight of all monomers (a) to (e). The (potentially) hydrophilic groups may be nonionic or preferably (potentially) ionic hydrophilic groups.

Particularly suitable nonionic hydrophilic groups are polyethylene glycol ethers composed of preferably 5 to 100, more preferably 10 to 80 ethylene oxide repeat units. The amount of polyethylene oxide units is generally from 0 to 10% by weight, preferably from 0 to 6% by weight, based on the weight of all monomers (a) to (e). Preferred monomers containing nonionic hydrophilic groups are polyethylene oxide glycols containing at least 20% by weight of ethylene oxide, polyethylene oxide monools and the reaction products of polyethylene glycol with diisocyanate carrying terminal etherified polyethylene glycol groups. Such diisocyanates and processes for their preparation are specified in the patents U.S. Pat. No. 3,905,929 and U.S. Pat. No. 3,920,598.

The ionic hydrophilic groups are in particular anionic groups, such as sulfonate, carboxylate and phosphate groups in the form of their alkali metal or ammonium salts, and cationic groups, such as ammonium groups, in particular protonated tertiary amino groups or quaternary ammonium groups. Potentially ionic hydrophilic groups are in particular those which can be converted into the abovementioned ionic hydrophilic groups by simple neutralization, hydrolysis or quaternization reactions, i.e. for example carboxylic acid groups or tertiary amino groups. The (potentially) ionic monomers (c) are described in detail, for example, in Ullmanns Enzyklopadie DER TECHNISCHEN CHEMIE, 4 th edition, volume 19, pages 311 to 313 and, for example, in DE-A1 495 745. The acid groups of the polyurethane are preferably neutralized to an extent of at least 10mol%, more preferably at least 40mol%, more preferably at least 70mol%, very preferably at least 90mol% and more particularly complete (100 mol%) with a suitable neutralizing agent, and are thus present in salt form, wherein the acid groups are anions and the neutralizing agent is present as cations. The neutralizing agent is, for example, ammonia, an alkali metal hydroxide such as NaOH or KOH, or an alkanol-amine. The (potentially) cationic monomers (c) of particular practical importance are in particular monomers containing tertiary amino groups, examples being tris (hydroxyalkyl) amines, N '-bis (hydroxyalkyl) alkylamines, N-hydroxyalkyl dialkylamines, tris (aminoalkyl) amines, N' -bis (aminoalkyl) alkylamines and N-aminoalkyl dialkylamines, the alkyl groups and alkanediyl units of these tertiary amines consisting of from 1 to 6 carbon atoms independently of one another. Also suitable are polyethers containing tertiary nitrogen atoms and preferably two terminal hydroxyl groups, such as may be obtained in a conventional manner, for example by alkoxylation of an amine containing two hydrogen atoms attached to the amine nitrogen, such as methylamine, aniline or N, N' -dimethylhydrazine. Such polyethers generally have a molecular weight of between 500g/mol and 6000 g/mol. These tertiary amines are converted to ammonium salts with acids, preferably strong mineral acids such as phosphoric acid, sulfuric acid, hydrohalic acids or strong organic acids, or by reaction with suitable quaternizing agents such as Ci to C6 alkyl halides or benzyl halides, for example bromides or chlorides.

Suitable monomers having (potentially) anionic groups generally include aliphatic, cycloaliphatic, araliphatic or aromatic carboxylic and sulfonic acids carrying at least one alcoholic hydroxyl group or at least one primary or secondary amino group. Preference is given to dihydroxyalkyl carboxylic acids, in particular dihydroxyalkyl carboxylic acids having 3 to 10C atoms, as also described in U.S. Pat. No. 3,412,054. Particularly preferred are compounds of the formula (c ₁)

Wherein R ¹ and R ² are C ₁ to C ₄ alkanediyl (units), and R ³ is C ₁ to C ₄ alkyl (units), and in particular dimethylolpropionic acid (DMPA). Also suitable are the corresponding dihydroxysulfonic acids and dihydroxyphosphonic acids such as 2, 3-dihydroxypropane phosphonic acid. Dihydroxy compounds having a molecular weight of more than 500g/mol to 10000g/mol and at least 2 carboxylate groups are also suitable, as are known from DE-A39 11 827. They can be obtained by reacting a dihydroxy compound with a tetracarboxylic dianhydride such as pyromellitic dianhydride or cyclopentanetetracarboxylic dianhydride in a molar ratio of 2:1 to 1.05:1 in an polyaddition reaction. Particularly suitable dihydroxy compounds are the monomers (b 2) and diols (b 1) listed as chain extenders.

Suitable monomers (c) containing amino groups reactive towards isocyanates include amino carboxylic acids, such as the adducts of lysine, b-alanine or aliphatic di-primary diamines specified in DE-A20 34479 with alpha, beta-unsaturated carboxylic acids or sulphonic acids. Such compounds conform to, for example, formula (c ₂)

H₂N-R⁴-NH-R⁵-X(c₂)

Wherein R ⁴ and R ⁵ are independently of each other a C ₁ to C ₆ alkanediyl unit, preferably ethylene, and X is COOH or SO 3H. Particularly preferred compounds of the formula (c ₂) are N- (2-aminoethyl) -2-aminoethanecarboxylic acid and also N- (2-aminoethyl) -2-aminoethane-sulfonic acid and the corresponding alkali metal salts, na being a particularly preferred counterion. Also particularly preferred are the adducts of the abovementioned aliphatic di-primary diamines with 2-acrylamido-2-methylpropanesulfonic acid, as described, for example, in DE-B1 954090. In the case of monomers having potentially ionic groups, their conversion to the ionic form can take place before, during or preferably after the isocyanate polyaddition, since the ionic monomers are generally not sufficiently soluble in the reaction mixture. Examples of neutralizing agents include ammonia, naOH, triethanolamine (TEA), triisopropylamine (TIPA) or morpholine, or derivatives thereof. The sulfonate or carboxylate groups are more preferably present in the form of their salts with alkali metal ions or ammonium ions as counter ions.

Monomers (d) which are different from monomers (a) to (c) and which may also be polyurethane components may be used for crosslinking or chain extension. They may include non-phenolic alcohols having a functionality of greater than 2, amines having 2 or more primary and/or secondary amino groups, and compounds bearing one or more primary and/or secondary amino groups in addition to one or more alcoholic hydroxyl groups. Alcohols having a functionality greater than 2 that can be used to establish a degree of branching or crosslinking include, for example, trimethylolpropane, glycerol or sugar. Other suitable compounds (d) are the alpha, omega-diaminopolyethers which can be prepared by amination of polyalkylene oxides with ammonia. The compounds (d) are also, for example, isocyanates which carry, in addition to the free isocyanate groups, further masked isocyanate groups, for example uretdione groups or carbodiimide groups.

Also suitable are monoalcohols which carry, in addition to the hydroxyl groups, further isocyanate-reactive groups, such as monoalcohols having one or more primary and/or secondary amino groups, for example monoethanolamine. Polyamines having 2 or more primary and/or secondary amino groups are used in particular when chain extension and/or crosslinking is carried out in the presence of water, since amines generally react faster with isocyanates than alcohols or water. This is generally necessary when crosslinked polyurethanes or aqueous dispersions of polyurethanes having a high molar weight are desired. In such cases, the approach taken is to prepare prepolymers with isocyanate groups, rapidly disperse them in water, and then subject them to chain extension or crosslinking by adding compounds with two or more isocyanate-reactive amino groups.

The amines suitable for this purpose are generally polyfunctional amines having a molar weight in the range from 32g/mol to 500g/mol, preferably from 60g/mol to 300g/mol, which polyfunctional amine comprises at least two amino groups selected from the group consisting of primary amino groups and secondary amino groups. Examples of such amines are diamines such as diaminoethane, diaminopropane, diaminobutane, diaminohexane, piperazine, 2, 5-dimethylpiperazine, amino-3-aminomethyl-3, 5-trimethyl-cyclohexane (isophoronediamine, IPDA), 4' -diaminodicyclohexylmethane, 1, 4-diaminocyclohexane, aminoethylethanolamine, hydrazine hydrate or triamines such as diethylenetriamine or 1, 8-diamino-4-aminomethyloctane. The amines may also be used in blocked form, for example in the form of the corresponding ketimines (see, for example, cA-A 1 129 128), ketazines (see, for example, U.S. Pat. No. 4,269,748) or amine salts (see, for example, U.S. Pat. No. 4,292,226). Oxazolidines such as used in US-a 4,192,937 also represent blocked polyamines which can be used to prepare the polyurethanes of the invention for chain extension of prepolymers. When such blocked polyamines are used, they are typically mixed with the prepolymer in the absence of water and this mixture is then mixed with or part of the dispersed water so that the corresponding polyamine is released by hydrolysis. It is preferred to use a mixture or combination of diamines and triamines, more preferably isophorone diamine (IPDA) and Diethylenetriamine (DETA).

The polyurethane preferably comprises as monomer (d) from 1 to 30mol%, more preferably from 4 to 25mol%, based on the total amount of components (b) and (d), of a polyamine having at least 2 isocyanate-reactive amino groups.

For the same purpose, it is also possible to use isocyanates having a functionality greater than two as monomers (d). Examples of standard commercially available compounds are the isocyanurate or biuret of hexamethylene diisocyanate.

The optionally used monomers (e) are monoisocyanates, monoalcohols, monoprimary amines and monoprimary amines. Their fraction is generally not more than 10mol%, based on the total molar amount of monomers. These monofunctional compounds generally carry other functional groups, such as olefinic or carbonyl groups, and are used to introduce functional groups into the polyurethane, which facilitates dispersion and/or crosslinking of the polyurethane or other polymer-like reactions. Monomers suitable for this purpose include monomers such as isopropenyl-a, a' -dimethylbenzyl isocyanate (TMI) and esters of acrylic or methacrylic acid such as hydroxyethyl acrylate or methacrylate.

The polyurethane of the aqueous polyurethane dispersion comprised in the at least partially coated particles and the shaped bodies according to the invention has a K-value of preferably above 40 and below 100, preferably from 55 to 95.

The K value is the relative viscosity number measured analogously to DIN EN ISO 1628-1 2021 at 25 ℃. It includes the flow rate of a1 wt.% strength solution of polyurethane in DMF relative to the flow rate of pure DMF and characterizes the average molecular weight of the polyurethane.

In the field of polyurethane chemistry, it is common knowledge how the molecular weight (and thus the K-value) of a polyurethane can be adjusted by selecting the arithmetic mean of the proportions of mutually reactive monomers and the number of reactive functional groups per molecule. Components (a) to (e) and their respective molar amounts are generally selected such that the ratio a: B is from 0.5:1 to 2:1, preferably from 0.8:1 to 1.5:1, more preferably from 0.9:1 to 1.2:1, wherein

A) Is the molar amount of isocyanate groups, and

B) Is the sum of the molar amount of hydroxyl groups and the molar amount of functional groups capable of reacting with isocyanate in an addition reaction. Very particularly preferably, the ratio A:B is as close to 1:1 as possible.

The monomers (a) to (e) employed generally carry on average from 1.5 to 2.5, preferably from 1.9 to 2.1, more preferably 2.0, isocyanate groups and/or functional groups which are capable of reacting with isocyanates in an addition reaction. Very high K values are achieved using small amounts of monomers (a) to (e) with a functionality >2.5 or monomers additionally carrying crosslinking groups such as carbodiimides, silanes, aziridines, etc.

The polyaddition of components (a) to (e) for the preparation of polyurethanes is preferably carried out at reaction temperatures of up to 180 ℃, more preferably up to 150 ℃, for example from 20 ℃ to 180 ℃, preferably from 70 ℃ to 150 ℃, at atmospheric pressure or under autogenous pressure. The preparation of polyurethanes and aqueous polyurethane dispersions is known to the person skilled in the art. Polyaddition of synthetic components for the preparation of polyurethanes can be catalyzed using organic or organometallic compounds. Suitable catalysts include dibutyltin Dilaurate (DBTL), tin (II) octoate, titanium tetrabutoxide (TBOT), or diazabicyclo [2.2.2] octane. Other suitable catalysts are salts of cesium, in particular cesium carboxylates, such as the formate, acetate, propionate, hexanoate or 2-ethylhexanoate of cesium.

The aqueous polyurethane dispersion used for the purposes of the present invention is a dispersion having an aqueous solvent as the continuous phase. Suitable aqueous solvents are water and mixtures of water and water-miscible solvents, examples being alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, n-hexanol and cyclohexanol, diols such as ethylene glycol, propylene glycol and butylene glycol, methyl or ethyl ethers of dihydric alcohols, diethylene glycol, triethylene glycol, polyethylene glycols having a number average molecular weight of up to about 3000, glycerol and dioxane, and ketones such as, in particular, acetone. Preferably, the polyurethane dispersion is substantially free of organic solvents. By "substantially free of organic solvent" is meant herein that the fraction of organic solvent is not greater than 5 wt%, more preferably not greater than 1 wt%, more particularly not greater than 0.1 wt%, based on the total weight of the solvent.

Preferably, the polyurethane is prepared in the presence of at least one organic solvent. Preferred organic solvents for the preparation of the polyurethane are ketones such as acetone and methyl ethyl ketone, and N-methylpyrrolidone. Acetone is particularly preferably used. When at least partially water miscible solvents are used to prepare polyurethanes, the polyurethane dispersions of the present invention may include organic solvents for such preparation in addition to water. It will be appreciated that the polyurethane dispersions of the present invention may be prepared in the presence of at least one organic solvent which is subsequently replaced in whole or in part by water.

The polyurethane dispersion may be prepared, for example, by one of the following methods, in which an ionic polyurethane is prepared from the synthesis components in a solvent which is miscible with water and boils below 100 ℃ at atmospheric pressure, according to the "acetone process". Sufficient water is added to form a dispersion, where water represents the cohesive phase. The "prepolymer mixing process" differs from the acetone process in that instead of fully reacted (potentially) ionic polyurethane, a prepolymer carrying isocyanate groups is first prepared. In this case, the components are selected such that the determined ratio A: B is greater than 1.0 and at most 3, preferably 1.05 to 1.5. The prepolymer is first dispersed in water and then optionally crosslinked by reacting the isocyanate groups with an amine bearing more than 2 isocyanate-reactive amino groups or chain extended by reacting the isocyanate groups with an amine bearing 2 isocyanate-reactive amino groups. Chain extension also occurs when no amine is added. In that case, the isocyanate groups are hydrolyzed to amino groups, which are consumed by reaction with the isocyanate groups remaining in the prepolymer, with concomitant chain extension. In general, if a solvent is also used during polyurethane preparation, the majority of the solvent is removed from the dispersion, for example by distillation under reduced pressure, which preferably has a solvent content of less than 10% by weight, and particularly preferably is solvent-free. Solvent is understood to mean an organic solvent.

In a first step a ₁) of the process of the invention, the particles are contacted with an aqueous polyurethane dispersion, the polyurethane having at least a first glass transition temperature T _g1 and a second glass transition temperature T _g2, wherein T _g1 is below 0 ℃ and T _g2 is above 25 ℃, resulting in at least partially coated particles.

Preferably, in step a ₁), the contacting is achieved by mixing the expanded beads with the dispersion using a kitchen or cement mixer or spray, such as mixing with a Vollrath mixer or spray drying. The amount of liquid/suspension phase in relation to the weight of the product may be in the range of 1ml/kg/min to 1000 ml/g/min. The size of the droplets may vary between 1mm and 1000mm in diameter. Suitable nozzles will be hollow cone nozzles, full cone nozzles or flat jet nozzles and jet discs which generate droplets by rotational movement and centrifugal force. A suitable mixer that may be used is EMT 30L. The EMT L30 is a discontinuous paddle mixer. It is suitable for mixing, agglomeration and coating experiments. Which consists of a rigid container with rotatable mixing means. Depending on the field of application, there are various mounting possibilities available. The mixer is heatable due to the double jacket. The rotational speed can be regulated by means of a mechanical transmission. Melt and pressure vessels are used to add liquid.

Preferably, in step a ₁), the contacting is achieved by mixing or spraying, preferably by mixing for 0.5 minutes to 6 hours, preferably 5 minutes to 1 hour, most preferably 5 minutes to 30 minutes and/or up to a residual water content of 3% or less based on the total weight of the at least partially coated particles. In the case of beads immersed in the dispersion, the contact time can be very short. The coated particles may then be dried to the desired moisture content, for example, by using, for example, a fluidized bed.

In general, usual coating methods, such as spraying, can be used, as described, for example, in EP 0009 727 A1. In a preferred embodiment of the coating, the particles are sprayed, which are kept in motion by blowing the particles with, for example, air or a mixture of different gases.

The at least partially coated particles are preferably coated in an amount of 0.1 to 40 wt%, preferably 5 to 25 wt%, based on the total weight of particles and coating. Preferably, the at least partially coated particles are coated in an amount of at least 90%, preferably at least 95%, more preferably at least 99%, more preferably fully coated, based on the total surface of the particles.

Step a ₂) refers to drying the coated particles. In principle, all suitable processes are possible, such as convection drying, contact drying, infrared drying and microwave technology.

In the case of contact drying, the temperature difference between the product and the wall should be limited to 1K-100K, in the case of convective drying the gas composition may be N ₂ or air. The amount of gas is preferably 1 to 1000 litres/minute per 1kg of product and the temperature of the product in the mixer should be between 1 and 100 ℃, preferably 10 to 60 ℃.

Preferably, during step a ₂), at least part of the coated particles remain mobile. This can prevent agglomeration of particles. Preferably, during step a ₂), the at least partially coated particles are kept moving until the particles are tack free, preferably until the residual water content is 3% or less based on the total weight of the at least partially coated particles.

Preferably, the particles are separated from each other after step a ₁) and before step a ₂). This can be achieved, for example, by using a vibrating belt or the like. In addition, this option also prevents agglomeration of the particles.

b ₁) coating the granules of expanded thermoplastic elastomer according to the process of the invention;

b ₂) shaping the granules obtained from step b ₁).

Preferably, the shaping in step b ₂) is performed by steam-free hot pressing.

Preferably, the hot pressing (also referred to as hot pressing or heated pressing) is performed at a temperature of 60 ℃ to 160 ℃, more preferably 80 ℃ to 160 ℃, even more preferably 90 ℃ to 150 ℃, even more preferably 90 ℃ to 140 ℃. The machine that can be used for compression molding of, for example, EVA polymers, will then be suitable for obtaining parts from the preferred E-TPU particles.

Preferably, after the molding by hot press, the resulting molded body is cooled to room temperature, which can improve mechanical properties.

In one embodiment of the invention, the molding (shaping) process may be performed by using an electromagnetic field to generate the required heat, either entirely or partially. The electromagnetic field is preferably in the range of 30kHz to 1GHz (corresponding to Radio Frequency (RF) and microwave molding) and more preferably 30kHz to 300MHz (corresponding to RF molding).

Thus, in a preferred embodiment, the shaping is performed by heat, wherein the heat is partly or completely generated by an electromagnetic field in the range of 30kHz to 1GHz, preferably in the radio frequency range (30 kHz to 300 MHz).

Shaping by energy radiation is generally carried out in the microwave frequency range of 300MHz to 300GHz or in the radio frequency range of 30kHz to 300 MHz. The microwaves are preferably applied in the frequency range between 0.5GHz and 100GHz, particularly preferably in the range between 0.8GHz and 10GHz, and the irradiation times used are between 0.1 minutes and 15 minutes. The radio waves are preferably applied in the frequency range between 500kHz and 100MHz, particularly preferably in the range between 1MHz and 80MHz, and the irradiation time used is between 0.1 minutes and 30 minutes.

Preferably, the shaped body is a composite of the particles with other materials such as textiles, leather, thermoplastic films or metal-containing components, in particular electronic components.

Another aspect of the invention relates to a method for handling a shaped body, comprising the steps of:

c ₁) preparing a shaped body according to the process of the invention;

c ₂) decomposing the particles by subjecting the shaped body to an alkaline aqueous fluid which may comprise a surfactant.

The at least partially coated particles according to the invention can be used neat, as a mixture of different particles and/or other materials to obtain 3D parts for industrial, consumer, transportation and construction applications, used alone or as components such as house, pipe or gas tank, shoe parts, midsole, insole, modular sole, bike saddle, bike tire, damping element, shock protection, sound and shock damping, upholstery, furniture upholstery, mattresses, yoga mats, bedding, railway litter, handles, protective sheets, packaging, fall protection, car interiors and exteriors, headliners, armrests, door liners, seats, battery housings, sports equipment, balls, tennis rackets, baseball clubs, treadmills, toys, floors, runways, artificial turf, playgrounds, gymnasiums and sidewalks, seals for sun.

Examples

The viscosity is measured according to DIN EN ISO 3219-2:2021 at 23℃and a shear rate of 250s ^-1.

The dispersion was dried in the mold at 40 ℃ for 3 days and then at 23 ℃ for 7 days. Thermal properties were measured by differential scanning calorimetry.

Glass transition temperature (as the midpoint temperature of the second heating curve at a heating rate of 20K/min), melting point and melting enthalpy were determined according to DIN ISO 11357 (2018) (melting point = peak temperature) by heating at 20K/min after cooling to-80 ℃, whereas melting enthalpy (Δh2) of the second wheel was calculated from the area of the second melting only;

a) Membrane in untreated state (drying see above)  Tm1, ΔH2 1

B) After heating the polyurethane film to 130℃and cooling to-80℃at 20K/min, reheating- > Tm2ΔH2 at 20K/min

K values are determined in accordance with DIN EN ISO 1628-1:2021.

Example EX1 dispersion with two Tg the highest Tg is above Room Temperature (RT) (allowing storage stable coated E-TPU Single beads)

Example EX1.1:

1039g of polyester diol (molecular weight 2000g/mol; monomer b 1)) from adipic acid and isophthalic acid (molar ratio 1:1) and 1, 6-hexanediol, 104,6g of dimethylolpropionic acid (DMPA, monomer C)), 186.8g of butanediol-1, 4 (monomer b 2) and 900g of IPDI (monomer a)) were reacted in 530g of anhydrous acetone in a pressurized reactor, starting at 50℃and increasing the temperature to 90℃in 30 minutes and then continuing at 90℃for 8 hours at 2.9 bar. The mixture was diluted with 1852g of acetone and cooled to 40 ℃ and expanded to atmospheric pressure. The NCO value was determined to be 1.2%. Then, 10.2g of isophorone diamine (monomer d) was added at a time, followed by 81g of diethyl ethanolamine (neutralizing agent) over 5min. After stirring for 5min, the dispersion step was continued with 3567g of deionized water at 30 ℃ over 37min, followed by the addition of 19.8 diethylenetriamine (monomer d) in 340g of deionized water over 30 min. Acetone was removed by vacuum distillation with the aid of 0.23g of defoamer (FoamStar PB 2724, basf) and the solids content was 37.4%.

Example EX1.2:

A solution of 1024g of polyester diol (molecular weight 2000g/mol, monomer b 1)) from adipic acid and isophthalic acid (mol 1:1) and 1,6 hexanediol, 104.6g of dimethylolpropionic acid (DMPA, monomer C)), 187g of butanediol-1, 4 (monomer b 2)) and 72.8g of side chain polyethylene glycol Ymer N (Perston, monomer C)) with 686.3g of IPDI (monomer a)) in 550g of anhydrous acetone was reacted in a pressurized reactor, starting at 55℃and increasing the temperature to 75℃in 30 minutes and then continuing at 75℃for 1.5 hours at 2.4 bar. Then, a second portion 228.8g of IPDI (monomer a)) and 18g of acetone were added and the reaction was continued until the NCO value was 2.2%. The mixture was diluted with 1574g of acetone and cooled to 40 ℃ and expanded to atmospheric pressure. The NCO value was found to be 1.39%. The mixture was then further diluted with 366g of acetone and 10.5g of isophorone diamine (monomer d)) were added in one portion, followed by 82.2g of diethyl ethanolamine (neutralizing agent) in 5min. After stirring for 10min, the dispersion step was continued with 3294g of deionized water at 39℃over 37min, followed by the addition of 19.8 diethylenetriamine (monomer d)) in 346g of deionized water over 30 min. Acetone was removed by vacuum distillation with the aid of 0.58g of defoamer (FoamStar PB 2724, basf) and the solids content was 37%.

Comparative example C1 amorphous Dispersion having a Tg < RT (resulting in sticky and non-storage-stable coated E-TPU beads)

706G of polypropylene oxide diol (molecular weight 2000g/mol, monomer b 1)) and 57.9g of dimethylolpropionic acid (DMPA, monomer C)) were reacted with 137.9g of toluene diisocyanate (80/20 isomer mixture, monomer a)) in 63g of anhydrous acetone at 110℃to an NCO content of < 0.1%. The mixture was then diluted with 720g of acetone and cooled to 25 ℃. The mixture was neutralized with 48.9g of aqueous NaOH (8 wt%) and dispersed with 710g of deionized water. Acetone was removed by vacuum distillation with the aid of 3 drops of Foam Star PB2724 (Basoff company) and the solids content was adjusted to 50%.

K value 43, no melting point or crystalline fraction can be detected

Comparative example C2 amorphous Dispersion having a Tg < RT (resulting in sticky and non-storage-stable coated E-TPU beads)

801.4G of polypropylene oxide diol (molecular weight 2000g/mol, monomer b 1) and 64.4g of dimethylolpropionic acid (DMPA, monomer C)) are reacted with 153.3g of toluene diisocyanate (80/20 isomer mixture, monomer a)) in 100g of anhydrous acetone at 100℃to 110℃to an NCO content of < 0.1%. The mixture was then diluted with 800g of acetone and cooled to 50 ℃. The mixture was neutralized with 19.4g of triethylamine and dispersed with 1580g of deionized water. Acetone was removed by vacuum distillation and the solids content was adjusted to 40%.

K value 43, melting point or crystalline fraction could not be detected

Comparative example C3 semi-crystalline Dispersion

676G of a polyester diol having a molecular weight of 2493g/mol (based on adipic acid and 1, 4-butanediol, monomer b 1)) were reacted with 0,11g of titanium tetrabutyrate, 40g of isophorone diisocyanate (IPDI, monomer a)), 0.77g of NCO-terminated polycarbodiimide (Elastostab H, pasteur company, monomer d)) at 60℃in 153g of anhydrous acetone for 60min. Then, 37.8g of 1, 6-hexane diisocyanate (HDI, monomer a)) was added and the temperature was raised to 74 ℃. The reaction was continued until the NCO value was below 1.25%. The mixture was diluted with 539g of acetone and cooled to 35-40 ℃. 22.4g of aminoethylaminoethane sulfonic acid sodium salt (50% aqueous solution, monomer c)) diluted with 22g of demineralized water was then added over a period of 3min, followed by 4.6g of isophorone diamine diluted in 23g of demineralized water over a period of 3 min. Before dispersion, 38.7g of a 20% aqueous solution of an alkyl polyglycol ether made of a linear saturated C16C18 fatty alcohol with 18 moles of ethylene oxide (20% active, e.g., lutensol AT18 from Basf Co.) was added. In the next step, the produced compound was dispersed with 463g of demineralized water over a period of 15min by using an anchor stirrer. Immediately after the water feed, 4g N- (2-aminoethyl) -ethanolamine (monomer d)) dissolved in 30g of water was additionally added during the dispersion. During dispersion, an additional amount of 200g of demineralized water was added.

After the dispersing step, the acetone is removed by vacuum distillation by means of two drops of defoamer (FoamStar PB 2724, basf) and the solids content of the semi-crystalline dispersion obtained is adjusted to 50% by adding a controlled amount of water. The properties of the obtained dispersion are shown in table 1.

TABLE 1

Example EX2 coated E-TPU beads

Example 2.1 coated e-TPU beads obtained by use of a Vollrate dissolver

The polyurethane dispersion described in example Ex1.1 was mixed with E-TPU beads (granules) prepared according to example 1 of WO 2013/153190 A1 having a bulk density of 130g/l and a particle weight of 27mg using a Vollrath dissolver at room temperature for 60 seconds. Subsequently, the beads were dried on teflon foil at room temperature, taking care to separate them from each other. The beads were collected after a period of about 10 minutes. The coated beads are non-tacky, storage stable, and can be collected without agglomeration.

Different coating amounts are achieved. There is 5% w/w to 20% w/w dispersion in the beads.

For example 5g of the coating are mixed with 95g of E-TPU beads to obtain a sample coated with 5% dispersion

Sample 1E-TPU beads coated with 5% Dispersion

Sample 2E-TPU beads coated with 10% Dispersion

Sample 3E-TPU beads coated with 15% Dispersion

Sample 4E-TPU beads coated with 20% Dispersion

Example 2.2 coated e-TPU beads obtained by use of a kitchen mixer

The polyurethane dispersion described in Ex 1.1 was mixed with the E-TPU beads having a bulk density of 130g/l and a particle weight of 27mg prepared according to example 1 of WO 2013/153190 A1 by means of a kitchen mixer (Bosch) equipped with a dough hook. The beads were coated with 10% w/w of the dispersion described in Ex 1.1. The beads were mixed until the water evaporated. For 100g of product, about 15 minutes until the granules dry. The process produces coated beads that are non-tacky and storage stable.

Example 2.3 coated e-TPU beads obtained by using a Cement mixer equipped with a mesh

2,75Kg of E-TPU beads with a bulk density of 130g/l and a particle weight of 27mg, prepared according to example 1 of WO 2013/153190 A1, are placed in a cement mixer (model mix 140) from Scheppach company equipped with a screen drum. 481g of the dispersion of example Ex 1.1 containing 1% blue dye are slowly added to the cement mixer under rotation. Within 90 seconds, the beads were fully coated. The beads were then passed to a screen drum so that individual coated beads were separated and collected on a bottom teflon belt. Within 10 minutes after coating, the beads were tack-free and could be collected and stored.

Example 2.4 coated beads obtained by use of a spray dryer apparatus

1.4Kg of E-TPU beads (prepared according to example 1 of WO 2013/153190 A1, bulk density 130g/l and particle weight 27 mg) are placed in a 30 liter slurry mixer (year 2013) from EMT GmbH, in which the beads are mixed with Becker blades at 100 rpm.

150G of the dispersion described in example Ex 1.1 were pumped via a gear pump at 3 bar to a nozzle (manufactured Shang Sipu Rayleigh spraying systems Co., ltd. (SPRAYING SYSTEMS)) having a diameter of 1.0mm, in which the dispersion was sprayed onto the moving E-TPU beads. The throughput was controlled at a flow rate of 75 g/min. The E-TPU beads were mixed and simultaneously coated at 100rpm for 2 minutes at 20 ℃. After the E-TPU beads have been coated, 1.0kg/h of nitrogen are flushed at 20℃into the mixer chamber via a separate tube of 4mm inner diameter to increase the drying strength by convection drying.

After 7 hours of drying, the pourable E-TPU beads were filled into plastic bags via a wing at the bottom of the mixer at a constant mixing speed of 100 rpm.

Example 2.5 coated e-TPU beads with lower Density obtained by use of kitchen Mixer

TPU precursor synthesis was carried out in a twin-screw extruder ZSK58 MC from Coperion, process length 48D (12 shells). Melt discharge from the extruder was performed by a gear pump. After melt filtration, the polymer melt is processed by underwater pelletization into pellets, which are dried continuously in a heated vortex bed at 40 ℃ to 90 ℃.

Polyol, chain extender and diisocyanate (table 2) were metered into the first zone. The housing temperatures are all in the range of 150 ℃ to 230 ℃. Melt discharge and underwater pelletization are performed at melt temperatures of 210 ℃ to 245 ℃. The screw speed is between 1801/min and 2401/min. The throughput is in the range of 180kg/h to 220 kg/h.

TABLE 2 TPU formulation

The dried TPU and additional materials listed in table 3 were fed into a twin screw extruder (ZE 40, claus ma-feebles tuff company (KraussMaffei Berstorff)) and melted in the temperature range of 160 ℃ to 220 ℃.

As blowing agents, 1.12 wt.% CO ₂ (based on the weight of the polymer composition) and 0.194 wt.% N ₂ (based on the weight of the polymer composition) were injected into the melt in the extruder and mixed with the thermoplastic polyurethane and other additives to form a homogeneous melt.

The molten mixture was then pressed via a gear pump into a perforated plate at a temperature of 180 to 200 ℃ at 160 to 200 ℃ and cut into granules in a cutting chamber (49 ℃ and 8.7 bar pressure) of the underwater granulation, which granules were subsequently expanded underwater.

After separating the expanded fines from the water via a centrifugal dryer, the expanded fines were dried at 60 ℃ for 2h.

TABLE 3 examples and reference TPU blends

	TPU1	Talkum 100	TPU compounded with 4,4' -MDI and oligomeric MDI having a functionality of 2.05 (Elastollan Xflex 2905 from Basoff Co.) in a separate extrusion process	High molecular weight high density polyethylene (Lupolen 4261 AG manufactured by Lyondell Basell, inc.)
					E-TPU	95 Parts of	0.1 Part	0.6 Part	5 Parts of

The E-TPU obtained, having a bulk density of 95g/L and a particle weight of 20mg, was mixed with the polyurethane dispersion described in Ex 1.1 by means of a kitchen mixer equipped with a dough hook. The beads were coated with 10% w/w of the dispersion described in Ex 1.1. The beads were mixed until the water evaporated. For 100g of product, about 15 minutes until the granules dry. The process produces coated beads that are non-tacky and storage stable.

Example 2.6 coated TPA expanded (E-TPA) beads obtained by Using a kitchen Mixer

The polyurethane dispersion described in Ex 1.1 was mixed with E-TPA (having a bulk density of 64g/l and a particle weight of 19 mg) prepared according to example 9 of WO2017220671 by means of a kitchen mixer equipped with a dough hook. The beads were coated with 10% w/w of the dispersion described in Ex 1.1. The beads were mixed until the water evaporated. For 100g of product, about 15 minutes until the granules dry. The process produces coated beads that are non-tacky and storage stable.

Example 2.7 coated TPA expanded (E-TPA) beads obtained by Using a kitchen Mixer

The polyurethane dispersion described in Ex 1.1 was mixed with E-TPA (having a bulk density of 40g/l and a particle weight of 17 mg) prepared according to example 12 of WO2017220671 by means of a kitchen mixer equipped with a dough hook. The beads were coated with 10% w/w of the dispersion described in Ex 1.1. The beads were mixed until the water evaporated. For 100g of product, about 15 minutes until the granules dry. The process produces coated beads that are non-tacky and storage stable.

Example 2.8 coated E-TPU expanded beads obtained by use of a kitchen mixer

The polyurethane dispersion described in Ex 1.1 was mixed with an E-TPU (having a bulk density of 77g/l and a particle weight of 40 mg) made from the exemplary E-TPU5 prepared from TPU1 according to WO2020136239 by means of a kitchen mixer equipped with a dough hook. The beads were coated with 10% w/w of the dispersion described in Ex 1.1. The beads were mixed until the water evaporated. For 100g of product, about 15 minutes until the granules dry. The process produces coated beads that are non-tacky and storage stable.

Example 2.9

The polyurethane dispersions described in example C1 and example C2 (Ex.2.2, sample 2) were mixed with E-TPU beads (granules) prepared according to example 1 of WO 2013/153190 A1 having a bulk density of 130g/l and a particle weight of 27mg using a Vollrath dissolver at room temperature for 60 seconds. Subsequently, the beads were dried on teflon foil at room temperature, taking care to separate them from each other. The beads were collected after a period of about 10 minutes. The beads are very sticky and cannot be collected without agglomeration.

For example 5g of the coating are mixed with 95g of E-TPU beads to obtain a coating of 5%

Samples of the dispersion

Sample 1E-TPU beads coated with 5% Dispersion

Sample 2E-TPU beads coated with 10% Dispersion

Sample 3E-TPU beads coated with 15% Dispersion

Sample 4E-TPU beads coated with 20% Dispersion

For all the different coating percentages, tacky and non-storage stable beads were obtained

Example 3:

Ex 3 plates made from coated E-TPU beads

Example 3.1 Hot pressboard with E-TPU beads according to experiment 2.1

65G of the coated beads according to experiment 2.1 (sample 2) were placed in a preheated mould of size (16.3X9.6X3.3) cm ³ (length, brightness, depth) which was previously sprayed with a silicone-based release agent (Indrosil 2000). The filled mold was covered with a mold cover (also sprayed Indrosil a with Indrosil a) which allowed 50% compression/compaction. The time in the heated press and the remaining time to cool the 3D part before demolding are summarized in the table below.

Furthermore, tensile strength and elongation measured according to ASTM D5035:2011 where (150X 25.4X 1.6) mm ³ e-TPU tape is used instead of fabric tape,

The rebound measured according to DIN 53512:2000-4 and the density of the resulting 3D part measured according to DIN EN ISO 845:2009-10 are also reported below.

For reference, 65g of E-TPU beads according to example 1 of WO 2013/153190 A1 having a bulk density of 130g/l are placed in a preheated mold of dimensions (16.3X19.6X13.3) cm ³ (length, brightness, depth). The filled mold was covered with a mold cover, which allowed 50% compression/compaction. This gives a panel (Ref.1) of the dimensions (16X 9.5X 1.6) cm ³. Hot press molded 3D parts obtainable from uncoated E-TPU beads are reported separately.

Mechanical data of hot platen:

experiment number	The dispersion of example 1	Temperature [ DEGC ]	Heating time [ min ]	Cooling [ min ]	Tensile Strength	Elongation [% ] of	Rebound [% ]	Density [ g/cm3]
									EX 3	10%	140	10	5	1.2	234	65	0.26
Ref-1	0%	140	10	5	0.7	100	73	0.29

Ref-1 is a reference example of our patent in which a plate is made of uncoated beads

Example 3.2A hotplate was obtained by using e-TPU beads coated according to Ex.2.5

60G of the coated beads e-TPU according to experiment 2.5 were placed in a preheated mould of dimensions (16.3X19.6X3.3) cm ³ (length, brightness, depth) which was previously sprayed with a silicone-based release agent (Indrosil 2000). The filled mold was covered with a mold cover (also sprayed Indrosil a with Indrosil a) which allowed 50% compression/compaction.

By circulating water into the walls of the closed mold, the material was pressed in a compression mold at 140 ℃ for 10 minutes and actively cooled to 23 ℃ for 5 minutes.

The stabilized panel may then be demolded

Example 3.3 Hot pressing plate obtained by using e-TPA beads coated according to Ex.2.6

40G of the coated beads e-TPA according to experiment 2.6 were placed in a preheated mould of size (16.3X19.6X13.3) cm ³ (length, brightness, depth) which was previously sprayed with a silicone-based stripper (Indrosil 2000). The filled mold was covered with a mold cover (also sprayed Indrosil a with Indrosil a) which allowed 50% compression/compaction.

The stabilized panel may then be demolded

Example 3.4 hot pressboard obtained by using e-TPU beads coated according to Ex.2.8

40G of coated beads e-TPA according to experiment 2.8 were placed in a preheated mould of size (16.3X19.6X13.3) cm ³ (length, brightness, depth) which was previously sprayed with a silicone-based stripper (Indrosil 2000). The filled mold was covered with a mold cover (also sprayed Indrosil a with Indrosil a) which allowed 50% compression/compaction.

The stabilized panel may then be demolded

Example 3.5 hot pressed plaques obtained by using e-TPU beads coated according to Ex.2.1 (sample 2) and e-TPA beads coated according to Ex.2.6

35G of the E-TPU coated beads according to Ex.2.1 (sample 2) were placed in a preheated mold of dimensions (16.3X19.6X13.3) cm ³ (length, brightness, depth) which was previously sprayed with a silicone-based stripper (Indrosil 2000). 20g of E-TPA coated according to Ex.2.6 was placed on top of the E-TPU beads. The filled mold was covered with a mold cover (also sprayed Indrosil a with Indrosil a) which allowed 50% compression/compaction.

The stabilized panel may be demolded. The plate comprises beads of different density and chemical nature. This experiment shows the possibility to realize plates with local density and chemical differences, as well as the possibility to tune the mechanical properties of the 3D object depending on the application specific.

Example 3.6 Hot-pressed plaques obtained by Low temperature Molding of coated e-TPU beads according to Ex.2.5

By circulating water into the walls of the closed mold, the material was pressed in a compression mold at 120 ℃ for 10 minutes and actively cooled to 23 ℃ for 5 minutes.

The stabilized panel may then be demolded

Example 4

Ex.4 flowability/caking test at high temperature (storage stability)

170G of E-TPU beads with a bulk density of 130g/l according to example 1 of WO 2013/153190 A1 coated with 10w/w% of the dispersion of example 1.1 are placed in a 15 cm-high cylinder with a diameter of 11 cm. A heavy cap of 800g was placed on the filled cylinder, which was stored at a temperature of 60 ℃.

After 1 hour, the cover was removed and the coated particles were released. No agglomeration or caking was observed.

The same experimental setup was used to evaluate the agglomeration behavior of coated beads over a 24 hour period. After 24 hours of storage at 60 ℃, the coated beads can also flow out without agglomerating.

For comparison, 170g of E-TPU beads with a bulk density of 130g/l according to example 1 of WO 2013/153190 A1 coated with 10w/w% of the dispersion of comparative example C3 were placed in a 15 cm-high cylinder with a diameter of 11 cm. A heavy cap of 800g was placed on the filled cylinder, which was stored at a temperature of 60 ℃. Upon re-moving the lid after 1 hour of storage, the beads did not flow out of the cylinder and agglomeration was observed.

Thus, the coated beads of example 2.1 (sample 2) showed a positive phenomenon of avoiding agglomeration when stored under defined pressure and at elevated temperature.

Furthermore, coating the beads by using a 9:1 w/w mixture of the polyurethane dispersions of example 1.1 and comparative example C3 (coating amount on the beads of 10 w/w%) also allowed to obtain coated beads that did not agglomerate after agglomeration testing at higher temperatures as described in example 4.

Example 5 demolding example

The molded plaques made according to example 3.6 were placed in a 2L Becher glass equipped with a magnetic stirrer, which was filled with 1000mL of water and 5g of PERSIL KRAFTGEL. The plate was stirred at a temperature of 90 ℃ for 30 minutes. Borrowed beads (load beads) may be recovered.

The decomposition was accelerated to 10 minutes by increasing the pH by adjusting the aqueous solution to a higher pH (ph=12) with NaOH.

This experiment shows that molded parts obtained by molding at lower temperatures, where only the surface coating holds the beads together, can be disassembled by recycling the beads.

Claims

1. A process for preparing storage stable coated particles of a moldable thermoplastic particle foam, the process comprising the steps of:

a ₁) contacting the particles with an aqueous polyurethane dispersion, the polyurethane having at least a first glass transition temperature T _g1 and a second glass transition temperature T _g2, wherein T _g1 is below 0 ℃ and T _g2 is above 25 ℃, the glass transition temperatures being measured according to DIN EN ISO 11357-2 (2014), resulting in at least partially coated particles;

a ₂) drying the coated particles.

2. The method of claim 1, wherein T _g1 is below-10 ℃.

3. The method of claim 1 or 2, wherein T _g2 is higher than 40 ℃.

4. A process according to any one of claims 1 to 3, wherein T _g2 is higher than 50 ℃.

5. The method of any one of claims 1 to 4, wherein T _g2 is greater than 60 ℃.

6. The method of any of claims 1-5, wherein the moldable thermoplastic particle foam is an expanded thermoplastic elastomer.

7. The method of any of claims 1-6, wherein the moldable thermoplastic particle foam is an expanded thermoplastic polyurethane.

8. The method of any one of claims 1 to 7, wherein the aqueous polyurethane dispersion has a solids content of at least 30 wt% based on the total weight of the dispersion.

9. The method of any one of claims 1 to 8, wherein the aqueous polyurethane dispersion has a solids content in the range of 35 wt% to 60 wt%, based on the total weight of the dispersion.

10. The method of any one of claims 1 to 9, wherein the aqueous polyurethane dispersion has a viscosity of less than 300mPas at 23 ℃ measured according to DIN EN ISO 3219-2:2021 at a shear rate of 23 ℃ and 250s ^-1.

11. The method of any one of claims 1 to 10, wherein the aqueous polyurethane dispersion has a viscosity of less than 200mPas at 23 ℃ measured according to DIN EN ISO 3219-2:2021 at a shear rate of 23 ℃ and 250s ^-1.

12. The method of any one of claims 1 to 11, wherein the polyurethane of the aqueous polyurethane dispersion has a T _g1 of-10 ℃ to-60 ℃ and a T _g2 of 60 ℃ to 90 ℃.

13. The method of any one of claims 1 to 12, wherein the polyurethane of the aqueous polyurethane dispersion is prepared from:

b2 At least one dihydroxy compound selected from the group consisting of branched or unbranched acyclic diols having 2 to 8C atoms or cyclic diols having 3 to 8C atoms;

c) At least one compound having at least one group which is reactive towards isocyanate groups and additionally carrying at least one ionic group or one group which can be converted into an ionic group,

D) Optionally, other compounds than a) to c).

14. The method according to claim 13, wherein the compound c) contains a group selected from carboxylate groups and sulfonate groups as an ionic group.

15. The process according to claim 13 or 14, wherein the aqueous polyurethane dispersion additionally comprises at least one additive selected from the group consisting of pigments, dyes, odorants, fillers, bio-based and/or biodegradable additives, UV stabilizers, heat stabilizers, flame retardants such as expandable graphite, additives that give antistatic properties, conductivity, additives that reduce soil absorption, anti-slip additives, antimicrobial additives, waxes, crosslinking agents, surface-functionalized fillers, foamable additives such as expancel, additives that can be irradiated by electromagnetic and/or radio frequency and/or microwaves, ionic surfactants, nonionic surfactants, rheology modifiers, fillers, anti-blocking additives, other aqueous dispersions, crosslinking agents, plasticizers, stabilizers against hydrolysis, defoamers and biocides.

16. The method according to any one of claims 1 to 15, wherein in step a ₁) the contacting is achieved by mixing or spraying.

17. The method according to any one of claims 1 to 16, wherein in step a ₁) the contacting is achieved by mixing for 0.5 minutes to 6 hours.

18. The method according to any one of claims 1 to 17, wherein in step a ₁ the contacting is achieved by mixing until the residual water content is 3% or less based on the total weight of the at least partially coated particles.

19. The method of any one of claims 1 to 18, wherein the at least partially coated particles are coated in an amount of 0.1 wt% to 40 wt% based on the total weight of particles and coating.

20. The method according to any one of claims 1 to 19, wherein during step a ₂) the at least partially coated particles are kept moving until the particles are tack-free.

21. The method according to any one of claims 1 to 20, wherein during step a ₂) the at least partially coated particles are kept moving until the residual water content is 3% or less based on the total weight of the at least partially coated particles.

22. The method of any one of claims 1 to 21, wherein the polyurethane in the polyurethane dispersion has a K value in the range of from above 40 to below 100 according to DIN EN ISO 1628-1 2021.

23. The method of any one of claims 1 to 22, wherein the polyurethane in the polyurethane dispersion has a K value in the range of 55 to 95 according to DIN EN ISO 1628-1 2021.

24. The method of any one of claims 1 to 23, wherein the particles comprise at least two particles based on different polymers or different particle sizes.

25. A method for producing a shaped body, comprising the steps of:

b ₁) coating particles of an expanded thermoplastic elastomer according to the process of any one of claims 1 to 24;

b ₂) shaping the granules obtained from step b ₁).

26. The method of claim 25, wherein the shaping in step b ₂) is performed by steam-free hot pressing.

27. The method of claim 26, wherein the hot pressing is performed at a temperature of 60 ℃ to 160 ℃.

28. The method of claim 25, wherein the hot pressing is performed at a temperature of 80 ℃ to 160 ℃.

29. The method of claim 25, wherein the hot pressing is performed at a temperature of 90 ℃ to 150 ℃.

30. The method of claim 25, wherein the hot pressing is performed at a temperature of 90 ℃ to 140 ℃.

31. The method of any one of claims 25 to 30, wherein the shaping is performed by heat, wherein the heat is generated partially or completely by an electromagnetic field in the range of 30kHz to 300 MHz.

32. A storage stable at least partially coated particle of a moldable thermoplastic particle foam, wherein the coating is a dried aqueous polyurethane dispersion, and wherein the polyurethane has at least a first glass transition temperature T _g1 and a second glass transition temperature T _g2, wherein T _g1 is below 0 ℃ and T _g2 is above 25 ℃.

33. Storage-stable at least partially coated particles of a moldable thermoplastic particle foam according to claim 32, obtainable by the process according to any one of claims 1 to 24.

34. A shaped body comprising the storage-stable at least partially coated particles according to claim 32 or 33.

35. Shaped body according to claim 34, obtainable by a method according to any one of claims 25 to 31.