Storage-stable coated particles and preparation thereof

Abstract

The invention relates to storage-stable coated particles and to a molded body comprising said coated particles and to a method for producing storage-stable coated particles for moldable thermoplastic particle foams, comprising the following steps: a1) bringing the particles into contact with an aqueous polyurethane dispersion, the polyurethane has a K value according to DIN EN ISO 1628-1 202 1 in the range of higher than 50 to lower than 100, preferably 55 to 95, thereby producing at least partially coated particles; a2) drying the coated particles. The invention also relates to a method for producing a shaped body, which comprises the above method as a first step, and to a method for handling said shaped body.

Description

[0001] Specification

[0002] The present invention relates to storage-stable coated particles, a molded body comprising said coated particles, and a method for producing storage-stable coated particles for producing moldable thermoplastic particle foams, the method comprising the steps of: a 1 ) bringing the particles into contact with a polyurethane aqueous dispersion having a K value in the range of above 50 to below 100, preferably 55 to 95, according to DIN EN ISO 1628-1 2021, thereby producing at least partially coated particles; a 2 ) drying the coated particles. The present invention also relates to a method for producing a molded body, which method comprises the above method as a first step, and also to a method for disposing of said molded body.

[0003] Moldable thermoplastic particle foams are used, for example, for producing any solid foam bodies such as fitness mats, body protectors, lining elements in automotive construction, sound and vibration dampers, packaging or shoe soles.

[0004] Generally, a mold is filled with foam particles, and then the individual foam particles are melted on their surfaces by the action of heat and connected to one another in this way to form a particle foam. Thus, in addition to simple products, complex semi-finished products or molded parts with undercuts can also be produced.

[0005] Moldable thermoplastic particle foams are known in the art and are described, for example, in Robin Britton (author), Update on Moldable Particle Foam Technology, Rapra technology Ltd, 2009. Expanded thermoplastic elastomers, especially expanded thermoplastic polyurethanes (E-TPU), represent specific moldable thermoplastic particle foams.

[0006] Expanded thermoplastic elastomers are known in the art. For example, WO 2018 / 082984 A1 describes particle foams based on expanded thermoplastic elastomers. WO2008 / 087078A1 describes a hybrid system consisting of foamed thermoplastic elastomers and polyurethanes.

[0007] Exemplary thermoplastic polymers are expanded thermoplastic polyurethanes (E-TPU), which are commercially available, for example, from BASF under the name for sale. E-TPU particles represent mostly to fully closed-cell particle foams. Thermoplastic polyurethanes (such as ) It expands to produce particulate foams and can be processed on standard molding machines. Due to the closed particulate surface and the chemical nature of the TPU used, standard E-TPU grades also absorb only small amounts of water. 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.

[0008] Rapid prototyping of 3D objects made of expanded thermoplastic elastomers is not currently easily achievable. Typically, isocyanate-containing binders are used to bond the particles or water vapor and appropriate machines such as steam chamber moldings. Due to health and safety reasons, energy costs, or due to the lack of availability of appropriate machines (steam chamber moldings), neither method is easily accessible. Additionally, the use of water vapor only allows the molding of the same type of particles, while the use of coatings on E-TPU particles or water-based binders allows the bonding of different types (glass transition temperature, melting point) and sizes of E-TPU particles, and also the bonding of different mixtures of different TPU or even different particulate foams such as E-TPS, E-PS, E-PP, E-TPA, E-TPC, E-TPO, etc. Applying coatings also allows the adjustment of mechanical properties and applicability by directly incorporating additives such as pigments or dyes, flame retardants, or antistatic agents onto the particle surface. Fillers, for example, allow an increase in the stiffness of the final component, while the use of additives that can be excited by an electromagnetic field, for example, allows the moldability of the coating and thus reduces the energy required for molding.

[0009] Additives that can be used are pigments, dyes, odorants, fillers, bio-based and / or biodegradable additives, UV stabilizers, heat stabilizers, flame retardants such as expandable graphite, additives that generate antistatic properties, conductivity, additives that reduce dirt absorption, antimicrobial additives, waxes, crosslinking agents, surface-functionalized fillers, foamable additives such as Expancell, additives that can be irradiated by an electromagnetic field and / or radio frequency and / or microwave.

[0010] WO 2022 / 223438 A1 describes different water-based binders for coating particles that can be shaped into the 3D component.

[0011] US 6 616 797 B1 describes the formation of an adhesive bond by a method that includes applying a dispersion of a polyurethane containing a structural unit of formula (I) to a surface. First, the dispersion is coated onto the surface to form a coating. The coating is dried to obtain a substantially water-free coating. Then the dried coating is thermally activated. The adhesive bond is formed by joining the thermally activated coating to itself or to another surface. However, particle coating is not described.

[0012] WO 2012 / 13506 A1 describes the use of a polyurethane aqueous dispersion adhesive for the production of a biodegradable composite film having at least two substrates bonded to each other using the polyurethane dispersion adhesive, wherein at least one substrate is a biodegradable polymer film. At least 60 wt% of the polyurethane is composed of a diisocyanate, a polyester diol, and at least one bifunctional carboxylic acid selected from dihydroxycarboxylic acids and diamino carboxylic acids.

[0013] 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 wt% of a polyurethane (excluding water or other organic solvents having a boiling point below 150 °C at 1 bar), which is applied to the substrate having a lower surface energy and the resulting adhesive-coated substrate is bonded to the substrate having a higher surface energy.

[0014] WO2021 / 7249749 describes the recovery of bonded articles, including TPU-foam substrates, by using a polyurethane aqueous dispersion of a specified molecular weight as an adhesive. It is not mentioned that the foamed particles are coated.

[0015] Although different binders generally used for bonding particles are described, there is still a need to prepare storage-stable coated particles in which the storage of the particles is prevented from agglomerating. This includes particles having better flowability, lower triboelectrostatic charging, and allowing easier realization of 3D components by using easy molding processes such as a standard convection oven or a hot press.

[0016] Therefore, there is a need for materials that should incorporate the following advantages:

[0017] a) Reducing the amount of binder by generating only a thin solid surface layer

[0018] b) Storage stability of the beads without accompanying agglomeration

[0019] c) Easy and versatile processability

[0020] d) Tunability of properties

[0021] Although the binder-particle mixture shows a certain viscosity, the solid coating of the particles allows for easy filling into, for example, a mold or cavity during processing due to better flowability and lower triboelectrostatic charging.

[0022] Additionally, the particles can be processed in different ways, such as by a standard convection oven or a hot press, but also by an electromagnetic field. Thereby, the beads can be, for example, filled into a gap and glued together by a trigger.

[0023] Therefore, an object of the present invention is to provide a method for preparing storage-stable coated particles.

[0024] This object is achieved by a method for producing storage-stable coated particles for moldable thermoplastic particle foams, the method comprising the following steps:

[0025] a 1 ) bringing the particles into contact with a polyurethane aqueous dispersion, the polyurethane having a K value in the range above 50 to below 100, preferably 55 to 95, according to DIN EN ISO

[0026] 1628-1 2021, thereby producing at least partially coated particles;

[0027] a 2 ) drying the coated particles.

[0028] 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 polyurethane aqueous dispersion, the polyurethane having a K value in the range above 50 to below 100, preferably 55 to 95, according to DIN EN ISO 1628-1 2021. The preferred at least partially coated particles of the moldable thermoplastic particle foam according to the invention can be obtained by the coating method according to the invention.

[0029] Another aspect of the invention is a shaped body comprising the storage-stable at least partially coated particles according to the invention. The preferred shaped body of the invention can be obtained by a method for producing a shaped body according to the invention.

[0030] Surprisingly, it has been found that the polyurethane in the polyurethane aqueous dispersion having the above K value can be used to achieve 3D components without the need for steam. The coating allows the achievement of 3D components with excellent mechanical values by hot pressing, which are comparable or even superior to 3D components manufactured by using a standard steam chamber molding process.

[0031] In particular, the preferred dispersion for the method of the invention can have a high solids content (>40%), but still exhibit a low viscosity. This allows the easy application of the dispersion to the particles. The particles are uniformly coated with a transparent 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 bead bridging upon cooling. Only moderate heating is required.

[0032] Furthermore, the coated particles surprisingly exhibit improved flow behavior, which is a very important factor when the particles are stored for a long time, for example, in an octabin, because in addition to the very interesting antistatic properties, blockage of the particles during storage can cause unpleasant problems at the customer's site.

[0033] - Additionally, the coating on the particle surface has additional advantages:

[0034] Particles with different sizes and chemical properties (such as E-TPU, E-TPS, E-PS, E-

[0035] TPO, E-PP, E-TPA, E-TPC) can be bonded together because the bonding ability comes from the coating rather than the melting of the particle walls. This has the following advantages: Particles with high melting points can also be processed into 3D components in a steamless process at a temperature of, for example, 100 °C.

[0036] - A hot press can be used, which has the advantage of avoiding steam and allowing the use of low-temperature molds. This results in energy savings and reduced complexity.

[0037] - Additives can be mixed with the coating and directly placed on the bead surface (surface modification. Interesting additives are thermally conductive particles, antistatic particles, flame retardants, dyes, UV stabilizers, ferromagnetic particles, anti-caking agents, etc.).

[0038] When using a water-redispersible dispersion, for example, by exposing the 3D component to alkaline conditions under stirring, the particles coated with the polyurethane dispersion described herein in the 3D component (molded body) can be decomposed.

[0039] When implementing the 3D component, another material (such as textiles, precursors, thermoplastic films, metal components) can be bonded to the particle in one step. This allows for the realization of various hybrid materials for different applications (sports (shoes) and leisure, automotive interiors, electronic applications, floorboards).

[0040] Although not preferred, as described for expanded beads in EP 3 338 984 B1, the coated particles can still be processed using a standard steam chamber molding process or other heating processes using high-energy radiation to increase the coating temperature, so they are compatible with existing customer equipment.

[0041] This process allows for the realization of 3D components with very complex geometries. The 3D component can still have empty spaces between the particles (allowing water penetration) or can have no empty spaces between the beads, which is highly desirable for sole manufacturing).

[0042] The method of the present invention relates to the preparation of coated particles of moldable thermoplastic particle foams. Such foams are known in the art (see, for example, Robin Britton (author), Update on Mouldable Particle Foam Technology, Rapra technology Ltd, 2009). Preferably, the moldable thermoplastic particle foam is an expanded thermoplastic elastomer.

[0043] Expandable thermoplastic elastomer particles are known in the art. Suitable thermoplastic elastomers are, for example, thermoplastic polyurethanes (TPU), thermoplastic polyester elastomers (such as polyether esters and polyester esters) (TPC), thermoplastic copolyamides (such as polyether copolyamides) (TPA), thermoplastic polyolefins (TPO) or thermoplastic styrene-butadiene block copolymers (TPS). Particulate foams based on thermoplastic polyurethane (TPU) are particularly preferred. Thus, preferably the expandable thermoplastic elastomer is E-TPU.

[0044] Examples of methods for preparing expandable thermoplastic elastomer particles are described in WO 2008 / 087078A1, WO2018 / 082984 A1, US10 005 218 B2 and WO 2007 / 082838 A1.

[0045] Preferably, the polymer dispersion used in the process according to the invention has a solids content of at least 40 wt.-%, more preferably in the range from 45 wt.-% to 60 wt.-%, based on the total weight of the dispersion.

[0046] Preferably, the polyurethane which belongs to the polymer dispersion and is included in at least partially coated particles and shaped bodies according to the invention has a viscosity measured at 23 °C and a shear rate of 250 s -1 at 23 °C of less than 300 mPas, preferably less than 200 mPas at 23 °C, according to DIN EN ISO 3219-2:2021.

[0047] Preferably, the polyurethane which belongs to the polyurethane dispersion and is included in at least partially coated particles and shaped bodies according to the invention has a glass transition temperature T g .

[0048] 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 when evaluating the second heating curve (heating rate 20 °C / min).

[0049] In a preferred embodiment of the invention, the polyurethane has at least a first glass transition temperature T g1 and a second glass transition temperature T g2 , where T g1 is below 0 °C and Tg2 Higher than 25 °C. More preferably, T g2 Higher than 40 °C, even more preferably higher than 50 °C, even more preferably higher than 60 °C. Generally, the polyurethane of the polyurethane aqueous dispersion has a T of -10 °C to -60 °C g1 and a T of 60 °C to 90 °C g2 . Preferably, the polyurethane exactly has two Ts g .

[0050] Preferably, the polyurethane belonging to the polyurethane aqueous dispersion and included in at least part of the coated particles and shaped bodies according to the present invention has a melting temperature T in the range of 30 °C to 100 °C, preferably 40 °C to 80 °C m .

[0051] The melting point and the enthalpy of fusion are determined by heating at 20 K / min after cooling to -80 °C according to DIN EN ISO 11357-3 (2018) (melting point = peak temperature); while the enthalpy of fusion in the second round (ΔH2) is calculated only based on the area of the second melting.

[0052] According to the present invention, the Ts g and Ts m mean that the polyurethane included in the polyurethane aqueous dispersion has these Ts g and Ts m values.

[0053] Generally, the polyurethane aqueous dispersion used in the method according to the present invention can be prepared by methods known in the art. Exemplary methods are described in WO 2021 / 249749 A1.

[0054] Thus, the polyurethane aqueous dispersion includes at least one polyurethane as a polymer binder dispersed in water and optionally additives. Preferred additives are selected from the group consisting of: ionic surfactants, non-ionic surfactants, rheology modifiers (including thickeners), anti-blocking additives, other aqueous dispersions, cross-linking agents, plasticizers, stabilizers against hydrolysis degradation, biocides, fillers and defoamers. The polymer binder preferably is in the form of a dispersion in water or in a mixture mainly composed of water and a water-soluble organic solvent with a boiling point preferably lower than 150 °C (1 bar). Water is particularly preferably used as the sole solvent.

[0055] The polyurethane dispersions used in the process according to the invention and included in at least partially coated particles and shaped bodies according to the invention comprise at least one polyurethane. Suitable polyurethanes can in principle be obtained by the reaction of at least one polyisocyanate with at least one compound having at least two groups reactive towards isocyanate groups. Polyurethanes also encompass so-called polyurethane-polyureas which, in addition to polyurethane groups, also have urea groups.

[0056] The polyurethane dispersions, at least partially coated particles and shaped bodies according to the invention preferably comprise at least one polyurethane which comprises at least one polyisocyanate and at least one polyol in the form of a copolymer. The polyurethane dispersions and at least partially coated particles and shaped bodies according to the invention preferably comprise at least one polyurethane which comprises at least one polyisocyanate and a diol component in the form of a copolymer, where a) 10 mol% - 100 mol% based on the total amount of diols have a molecular weight of 500 g / mol to 5000 g / mol and b) 0 mol% - 90 mol% based on the total amount of diols have a molecular weight of 60 g / mol to less than 500 g / mol. Polymer polyols are preferred. Suitable polymer polyols are preferably selected from polyester diols, polyether diols and mixtures thereof. The polymer polyols preferably have a number-average molecular weight of about 500 g / mol to 5000 g / mol.

[0057] The polyurethanes are preferably synthesized to an extent of at least 40% by weight, more preferably at least 60% by weight and very preferably at least 80% by weight, based on the total weight of the monomers used for the preparation of the polyurethanes, of at least one diisocyanate and at least one polyether diol and / or polyester diol. Suitable other synthesis components up to 100% by weight are, for example, polyisocyanates having at least three NCO groups and compounds different from polymer polyols and having at least two groups reactive towards isocyanate groups as defined below. These include, for example, non-polymer diols; diamines; polymers different from polymer polyols and having at least two active hydrogen atoms per molecule; compounds having two active hydrogen atoms and at least one ionizable / ionic group per molecule; and mixtures thereof.

[0058] The polyurethanes of the polyurethane aqueous dispersions adhesives preferably have crystallinity.

[0059] Preferred polyurethanes are synthesized from:

[0060] a) at least one monomeric diisocyanate,

[0061] b) at least one diol, component (b) comprising at least one diol having a number-average molecular weight in the range from 500 g / mol to 5000 g / mol,

[0062] c) at least one monomer different from monomers (a) and (b), having at least one isocyanate group or at least one group reactive towards an isocyanate group and additionally carrying at least one hydrophilic group or potentially hydrophilic group,

[0063] d) optionally at least one other compound different from monomers (a) to (c), having at least two reactive groups selected from alcoholic hydroxyl groups, primary or secondary amino groups or isocyanate groups, and

[0064] e) optionally at least one monofunctional compound different from monomers (a) to (d), having one reactive group as an alcoholic hydroxyl group, primary or secondary amino group or isocyanate group.

[0065] Preferably, the polyurethane dispersion is an anionic polyurethane dispersion produced with a small amount of aromatic diisocyanate or without aromatic diisocyanate, for example less than 60 mol% based on the total amount of all organic diisocyanates a). The anionic groups of the anionic polyurethane are preferably selected from carboxylate and sulfonate. This also applies to the polyurethane included in at least partially coated particles and shaped bodies according to the invention.

[0066] Component b) preferably consists of:

[0067] b1) 10 mol% to 100 mol% of a diol having a molecular weight of 500 g / mol to 5000 g / mol based on the total amount of component b),

[0068] b2) 0 mol% to 90 mol% of a diol having a molecular weight of 60 g / mol to less than 500 g / mol based on the total amount of component b).

[0069] The molar ratio of diol b1) to monomer b2) is more preferably 1:5 to 5:1, more preferably 1:2 to 2:1. More preferably, b2) is not used. More particularly, diol b) is selected from polytetrahydrofuran, polypropylene oxide and polyester diols, and the polyester diols are selected from the reaction products of dihydroxy alcohols and dicarboxylic acids and lactone-based polyester diols.

[0070] The diisocyanate X(NCO) can be specifically mentioned 2monomer (a), wherein X is an acyclic aliphatic hydrocarbon group having 4 to 15 carbon atoms, an alicyclic or aromatic hydrocarbon group having 6 to 15 carbon atoms, or an araliphatic hydrocarbon group having 7 to 15 carbon atoms. Examples of such diisocyanates include tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,5,5-trimethyl-3-isocyanatomethylcyclohexane (IPDI), 2,2-bis(4-isocyanatocyclohexyl)propane, trimethylhexane diisocyanate, 1,4-diisocyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene (TDI), 4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyanatodiphenylmethane, p-phenylene 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-3,5,5-trimethyl-3-isocyanatomethylcyclohexane, 2,6-diisocyanatotoluene and tetramethylxylylene diisocyanate or mixtures thereof. Particularly important mixtures of these isocyanates are mixtures of the corresponding structural isomers of diisocyanatotoluene and diisocyanatodiphenylmethane; a mixture of 80 mol% of 2,4-diisocyanatotoluene and 20 mol% of 2,6-diisocyanatotoluene is particularly suitable. In addition, particularly advantageous are mixtures of aromatic isocyanates such as 2,4-diisocyanatotoluene and / or 2,6-diisocyanatotoluene with aliphatic or alicyclic isocyanates such as hexamethylene diisocyanate or IPDI, in which case the preferred mixing molar ratio of the aliphatic isocyanate to the 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.

[0071] The diol (b1) may be, for example, a polyester polyol known from Ullmanns Enzyklopadie der technischen Chemie, 4th edition, volume 19, pages 62-65. It is preferred to use a polyester polyol obtained by reacting a dihydric alcohol with a dicarboxylic acid. The corresponding polycarboxylic anhydride or the corresponding polycarboxylic acid ester of a lower alcohol or a mixture thereof may also be used instead of the free polycarboxylic acid to prepare the polyester polyol. The polycarboxylic acid may be aliphatic, alicyclic, aromatic, aromatic or heterocyclic and may optionally be substituted and / or unsaturated by, for example, halogen atoms. Examples thereof include the following: suberic acid, azelaic acid, phthalic acid, isophthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid and dimerized fatty acids. Preferred dicarboxylic acids are of the general formula HOOC-(CH 2 ) y -COOH dicarboxylic acids, wherein y is a number from 1 to 20, preferably an even number from 2 to 20, are exemplified by succinic acid, adipic acid, sebacic acid and dodecanedicarboxylic acid. 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-methylpropane-1,3-diol, methylpentanediol, and diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol and dibutylene glycol and polybutylene glycol. In order to obtain crystallinity, preferred alcohols are of the general formula HO-(CH 2 ) x An alcohol having -OH, wherein x is a number from 1 to 20, preferably an even number from 2 to 20. Examples of such alcohols are ethylene glycol, butane-1,4-diol, hexane-1,6-diol, octane-1,8-diol and dodecane-1,12-diol.

[0072] The diol (b1) may also be a polycarbonate diol such as is obtainable, for example, by reacting phosgene with an excess of a low molecular weight alcohol specified as a synthesis component for the polyester polyol.

[0073] The diols (b1) may also be lactone-based polyester diols which are homopolymers or copolymers of lactones, preferably hydroxy-terminated addition products of lactones with suitable difunctional starter molecules.

[0074] To achieve crystallinity, the preferred lactones contemplated are those derived from the general formula HO-(CH 2 ) zLactones of compounds with -COOH, where z is a numerical value from 1 to 20, and where one or more H atoms of the methylene units can also be substituted by C1 - C4 alkyl groups. Examples are ε - caprolactone, β - propiolactone, γ - butyrolactone and / or methyl - γ - caprolactone and mixtures thereof. Examples of suitable initiator components are the low - molecular - weight dihydroxy alcohols specified above as synthesis components for polyester polyols. The corresponding polymers of ε - caprolactone are particularly preferred. Lower - molecular - weight polyester diols or polyether diols can also be used as initiators for the preparation of lactone polymers. The corresponding chemically equivalent polycondensates of the hydroxycarboxylic acids corresponding to the lactones can also be used instead of the polymers of the lactones.

[0075] The diol (b1) can also be a polyether diol. Polyether diols can be obtained in particular by polymerizing ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin with themselves, for example in the presence of BF3, or by subjecting these compounds, optionally in mixture or continuously, to an addition reaction with initiator components containing reactive hydrogen atoms, such as alcohols or amines, examples being water, ethylene glycol, propane - 1,2 - diol, propane - 1,3 - diol, 2,2 - 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. A particularly preferred polyether diol is polytetrahydrofuran. Suitable polytetrahydrofuran can be prepared by the cationic polymerization of tetrahydrofuran in the presence of an acidic catalyst such as sulfuric acid or fluorosulfuric acid. This preparation method is known to those skilled in the art.

[0076] The compounds classified under b1) only include those polyether diols consisting of less than 20% by weight of ethylene oxide, based on their total weight. Polyether diols having at least 20% by weight of incorporated ethylene oxide units are counted as the hydrophilic polyether diols of monomer c).

[0077] Polyhydroxy olefins, preferably polyhydroxy olefins having 2 terminal hydroxy groups, such as α,ω - dihydroxy polybutadiene, α,ω - dihydroxy polymethacrylate or α,ω - dihydroxy polyacrylate can also be used as monomer bi). Such compounds are known, for example, from EP - A 622 378. Other suitable polyols are polyacetals, polysiloxanes and alkyd resins.

[0078] The hardness and elastic modulus of the polyurethane can be increased by using not only the diol (b1) but also a low - molecular - weight diol (b2) having a molecular weight of about 60 g / mol to less than 500 g / mol, preferably 62 g / mol to 200 g / mol, as the diol (b).

[0079] The monomer (b2) used is in particular a synthetic component of short-chain alkanediols which are provided for the preparation of polyester polyols, preferably unbranched diols having 2 to 12 C atoms and an even number of C atoms and pentane-1,5-diol and neopentyl glycol. Examples of suitable diols (b2) 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-methylpropane-1,3-diol, methylpentanediol, furthermore diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycol. For obtaining crystallinity, preference is given to alcohols of the general formula HO-(CH 2 ) x -OH, where x is a numerical value from 1 to 20, preferably an even number from 2 to 20. Examples thereof are ethylene glycol, butane-1,4-diol, hexane-1,6-diol, octane-1,8-diol and dodecane-1,12-diol.

[0080] In order to render the polyurethanes dispersible in water, they comprise as a synthetic component a monomer (c) which carries at least one isocyanate group or at least one group which is reactive towards an isocyanate group and furthermore at least one hydrophilic group or a group which is capable of being 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 group with the isocyanate is substantially lower than that of the functional groups of the monomers used for synthesizing the polymer backbone. The fraction of the component having the (potentially) hydrophilic group in the total amount of components (a) to (e) generally is such that the molar amount of the (potentially) hydrophilic group is 30 mmol / kg to 1000 mmol / kg, preferably 50 mmol / kg to 500 mmol / kg and more preferably 80 mmol / kg to 300 mmol / kg, based on the amount by weight of all monomers (a) to (e). The (potentially) hydrophilic group can be a nonionic or preferably a (potentially) ionic hydrophilic group.

[0081] Particularly suitable non-ionic hydrophilic groups are polyethylene glycol ethers composed of preferably 5 to 100, more preferably 10 to 80 ethylene oxide repeating units. The amount of polyethylene oxide units is generally 0 wt% to 10 wt%, preferably 0 wt% to 6 wt% based on the weight of all monomers (a) to (e). Preferred monomers containing non-ionic hydrophilic groups are polyethylene oxide diols, polyethylene oxide monoalcohols, and reaction products of polyethylene glycol with diisocyanates carrying terminal etherified polyethylene glycol groups containing at least 20 wt% of ethylene oxide. Such diisocyanates and their preparation methods are specified in patents US-A 3,905,929 and US-A 3,920,598.

[0082] Ionic hydrophilic groups are particularly anionic groups such as sulfonate, carboxylate, and phosphate groups in the form of their alkali metal salts or ammonium salts, and cationic groups such as ammonium groups, especially protonated tertiary amino groups or quaternary ammonium groups. Potentially ionic hydrophilic groups are particularly those ionic hydrophilic groups that can be converted into the above-mentioned ionic hydrophilic groups by simple neutralization, hydrolysis, or quaternization reactions, i.e., for example, carboxylic acid groups or tertiary amino groups. The (potentially) ionic monomer (c) is described in detail, for example, in Ullmanns Enzyklopadie der technischen Chemie, 4th edition, volume 19, pages 311 - 313 and, for example, in DE-A 1 495 745. The acid groups of the polyurethane are preferably neutralized with a suitable neutralizing agent to at least 10 mol%, more preferably at least 40 mol%, more preferably at least 70 mol%, very preferably at least 90 mol% and more particularly completely (100 mol%), and thus exist in the form of salts, where the acid groups are anions and the neutralizing agent exists as a cation. The neutralizing agent is, for example, ammonia, alkali metal hydroxides such as NaOH or KOH, or alkanol-amines. (Potentially) cationic monomers (c) of particular practical importance are particularly monomers containing tertiary amino groups, examples being tris(hydroxyalkyl)amines, N,N'-bis(hydroxyalkyl)alkylamines, N-hydroxyalkyldialkylamines, tris(aminoalkyl)amines, N,N'-bis(aminoalkyl)alkylamines, and N-aminoalkyldialkylamines, where the alkyl groups and alkanediyl units of these tertiary amines independently of one another consist of 1 to 6 carbon atoms. Also suitable are polyethers containing a tertiary nitrogen atom and preferably two terminal hydroxy groups that can be obtained in a conventional manner, for example, by alkoxylation of amines containing two hydrogen atoms attached to the amine nitrogen, such as methylamine, aniline, or N,N'-dimethylhydrazine. Such polyethers generally have a molecular weight between 500 g / mol and 6000 g / mol. These tertiary amines are converted into ammonium salts with an acid, preferably a strong inorganic acid such as phosphoric acid, sulfuric acid, hydrohalic acid, or a strong organic acid, or by reaction with a suitable quaternizing agent such as C1 to C6 alkyl halides or benzyl halides, for example, bromides or chlorides.

[0083] Suitable monomers having (potentially) anionic groups generally include aliphatic, cycloaliphatic, araliphatic or aromatic carboxylic and sulfonic acids carrying at least one alcohol hydroxyl group or at least one primary or secondary amino group. Preferred are dihydroxyalkyl carboxylic acids, especially dihydroxyalkyl carboxylic acids having 3 to 10 C atoms, such as also described in US-A 3,412,054. Particularly preferred are compounds of the general formula (c1)

[0084]

[0085] 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 especially dimethylolpropionic acid (DMPA). Also suitable are the corresponding dihydroxy sulfonic acids and dihydroxy phosphonic acids such as 2,3-dihydroxypropane phosphonic acid. Also suitable are dihydroxy compounds having a molecular weight of greater than 500 g / mol to 10,000 g / mol and at least 2 carboxylic acid groups known from DE-A 39 11 827. They can be obtained by reacting a dihydroxy compound with a tetracarboxylic dianhydride such as pyromellitic dianhydride or cyclopentanetetracarboxylic dianhydride in a polyaddition reaction in a molar ratio of 2:1 to 1.05:1. Particularly suitable dihydroxy compounds are the monomers (b2) and the diols (b1) listed as chain extenders.

[0086] Suitable monomers (c) containing amino groups reactive towards isocyanates include amino carboxylic acids such as lysine, β-alanine as defined in DE-A 20 34479 or adducts of aliphatic di-primary diamines with α,β-unsaturated carboxylic or sulfonic acids. Such compounds conform, for example, to the formula (c2)

[0087] H 2 N-R 4 -NH-R 5 -X (c2)

[0088] wherein R 4 and R 5 are independently of one another C 1 to C 6an alkanediyl unit, preferably an ethylene group, and X is COOH or SO3H. Particularly preferred compounds of formula (c2) are N-(2-aminoethyl)-2-aminoethane carboxylic acid and N-(2-aminoethyl)-2-aminoethanesulfonic acid and the corresponding alkali metal salts, where Na is the particularly preferred counterion. Also particularly preferred are the adducts of the above-mentioned aliphatic di-primary diamines with 2-acrylamido-2-methylpropane sulfonic acid, as described, for example, in DE-B 1 954090. In the case of using monomers with potentially ionic groups, their conversion to the ionic form can be carried out before, during or preferably after the isocyanate polyaddition, since ionic monomers usually do not dissolve sufficiently in the reaction mixture. Examples of neutralizing agents include ammonia, NaOH, triethanolamine (TEA), triisopropylamine (TIPA) or morpholine, or their derivatives. The sulfonate or carboxylate groups are more preferably present in the form of their salts with alkali metal ions or ammonium ions as counterions.

[0089] Monomer (d), which is different from monomers (a) to (c) and can also be a polyurethane component, can be used for crosslinking or chain extension. They can include non-phenolic alcohols with functionality greater than 2, amines with two or more primary amino groups and / or secondary amino groups, and compounds that carry one or more primary amino groups and / or secondary amino groups in addition to one or more alcoholic hydroxyl groups. Alcohols with functionality greater than 2 that can be used to establish a certain degree of branching or crosslinking include, for example, trimethylolpropane, glycerol or sugars. Other suitable compounds (d) are α,ω-diaminopolyethers that can be prepared by amination of polyalkylene oxides with ammonia. Compound (d) is also, for example, an isocyanate that carries other masked isocyanate groups, such as uretdione groups or carbodiimide groups, in addition to free isocyanate groups.

[0090] Also suitable are monoalcohols that carry other isocyanate-reactive groups in addition to the hydroxyl group, such as monoalcohols with one or more primary amino groups and / or secondary amino groups, for example monoethanolamine. Polyamines with two or more primary amino groups and / or secondary amino groups are particularly used when chain extension and / or crosslinking is carried out in the presence of water, since amines generally react with isocyanates faster than alcohols or water. This is usually necessary when a water dispersion of a crosslinked polyurethane or a polyurethane with a high molar weight is desired. In such cases, the method is to prepare a prepolymer with isocyanate groups, rapidly disperse it in water, and then subject them to chain extension or crosslinking by adding a compound with two or more isocyanate-reactive amino groups.

[0091] Amines suitable for this purpose are generally polyfunctional amines with a molar weight in the range of 32 g / mol to 500 g / mol, preferably 60 g / mol to 300 g / mol, which include 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-3,5,5-trimethyl-cyclohexane (isophorone diamine, IPDA), 4,4'-diaminodicyclohexylmethane, 1,4-diaminocyclohexane, aminoethyl ethanolamine, hydrazine, hydrazine hydrate or triamines such as diethylenetriamine or 1,8-diamino-4-aminomethyloctane. The amines can 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 US-A4,269,748) or amine salts (see US-A 4,292,226). Oxazolidines used, for example, in US-A4,192,937 also represent blocked polyamines which can be used for the chain extension of prepolymers for the preparation of the polyurethanes of the present invention. When using such blocked polyamines, they are generally mixed with the prepolymer in the absence of water, and then this mixture is mixed with dispersed water or with a part of the dispersed water so that the corresponding polyamine is released by hydrolysis. Preferably, a mixture of diamines and triamines, more preferably a mixture of isophorone diamine (IPDA) and diethylenetriamine (DETA), is used.

[0092] The polyurethane preferably comprises 1 mol% to 30 mol%, more preferably 4 mol% to 25 mol%, based on the total amount of components (b) and (d), of a polyamine having at least 2 isocyanate-reactive amino groups as monomer (d).

[0093] For the same purpose, polyisocyanates with a functionality greater than two can also be used as monomer (d). Examples of standard commercially available compounds are the isocyanurates or biurets of hexamethylene diisocyanate.

[0094] Optionally used monomer (e) is monoisocyanate, monoalcohol and mono-primary and mono-secondary amines. Their fraction is generally not more than 10 mol% based on the total molar amount of the monomers. These monofunctional compounds usually carry other functional groups such as olefinic groups or carbonyl groups and are used to introduce functional groups into the polyurethane, which facilitates the dispersion and / or crosslinking of the polyurethane or the reaction of other similar polymers. Monomers suitable for this purpose include monomers such as isopropenyl-a,a'-dimethylbenzyl isocyanate (TMI) and esters of acrylic or methacrylic acid such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.

[0095] Having at least a first glass transition temperature T g1and a second glass transition temperature T g2 The polyurethane of the polyurethane aqueous dispersion can be prepared from the following:

[0096] a) at least one organic diisocyanate selected from 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, and the amount of the aromatic diisocyanate is less than 60 mol-% based on the sum of all the organic diisocyanates a);

[0097] b1) at least one dihydroxy compound having a molecular weight of 500 g / mol to 5000 g / mol and selected from the group consisting of polyester diols, polyether diols and polytetrahydrofuran;

[0098] b2) at least one dihydroxy compound selected from the group consisting of branched or unbranched acyclic diols having 2 to 8 C atoms and cyclic diols having 3 to 8 C atoms, and the at least dihydroxy compound preferably has a molecular weight of 62 g / mol to 200 g / mol;

[0099] c) at least one compound having at least one group reactive with an isocyanate group and additionally carrying at least one ionic group or a group capable of being converted into an ionic group, and the compound c) preferably contains a group selected from a carboxylate group and a sulfonate group,

[0100] d) optionally other compounds different from a) to c).

[0101] The preferred polyurethane is synthesized from the following:

[0102] a) at least one monomeric diisocyanate,

[0103] b) at least the diols b1) and b2),

[0104] c) at least one monomer different from the monomers (a) and (b), having at least one isocyanate group or at least one group reactive with an isocyanate group and additionally carrying at least one hydrophilic group or a potentially hydrophilic group,

[0105] d) optionally at least one other 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

[0106] e) optionally at least one monofunctional compound different from the monomers (a) to (d), having one reactive group as an alcoholic hydroxyl group, primary or secondary amino group or isocyanate group.

[0107] Preferably, the polyurethane dispersion is an anionic polyurethane dispersion produced with little or no aromatic diisocyanate, for example less than 60 mol% based on the total of all organic diisocyanates a). The anionic groups of the anionic polyurethane are preferably selected from carboxylate and sulfonate. This also applies to the polyurethanes comprised in the at least partially coated particles and shaped bodies according to the invention.

[0108] Component b) preferably consists of:

[0109] b1) 10 mol% to 90 mol% of diol b1) based on the total amount of component b),

[0110] b2) 10 mol% to 90 mol% of diol b2) based on the total amount of component b).

[0111] The molar ratio of diol b1) to monomer b2) is more preferably 1:5 to 5:1, more preferably 1:2 to 2:1.

[0112] The diisocyanate X(NCO) may be specifically mentioned 2monomer (a), where X is an acyclic aliphatic hydrocarbon group having 4 to 15 carbon atoms, an alicyclic or aromatic hydrocarbon group having 6 to 15 carbon atoms, or an araliphatic hydrocarbon group having 7 to 15 carbon atoms. Examples of such diisocyanates include tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,5,5-trimethyl-3-isocyanatomethylcyclohexane (IPDI), 2,2-bis(4-isocyanatocyclohexyl)propane, trimethylhexane diisocyanate, 1,4-diisocyanatobenzene, 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene (TDI), 4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyanatodiphenylmethane, p-phenylene 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-3,5,5-trimethyl-3-isocyanatomethylcyclohexane, 2,6-diisocyanatotoluene, and tetramethylxylylene diisocyanate or mixtures thereof. Particularly important mixtures of these isocyanates are mixtures of the corresponding structural isomers of diisocyanatotoluene and diisocyanatodiphenylmethane; a mixture of 80 mol% 2,4-diisocyanatotoluene and 20 mol% 2,6-diisocyanatotoluene is particularly suitable. In addition, particularly advantageous are mixtures of aromatic isocyanates such as 2,4-diisocyanatotoluene and / or 2,6-diisocyanatotoluene with aliphatic or alicyclic isocyanates such as hexamethylene diisocyanate or IPDI, in which case the preferred mixing molar ratio of the aliphatic isocyanate to the 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.

[0113] The diol (b1) may be, for example, a polyester polyol known from Ullmanns Enzyklopadie der technischen Chemie, 4th edition, volume 19, pages 62-65. It is preferred to use a polyester polyol obtained by reacting a dihydric alcohol with a dicarboxylic acid. The corresponding polycarboxylic anhydride or the corresponding polycarboxylic acid ester of a lower alcohol or a mixture thereof may also be used instead of the free polycarboxylic acid to prepare the polyester polyol. The polycarboxylic acid may be aliphatic, alicyclic, aromatic, aromatic or heterocyclic and may optionally be substituted and / or unsaturated by, for example, halogen atoms. Examples thereof include the following: suberic acid, azelaic acid, phthalic acid, isophthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid and dimerized fatty acids. Preferred dicarboxylic acids are of the general formula HOOC-(CH 2 ) y -COOH dicarboxylic acids, wherein y is a number from 1 to 20, preferably an even number from 2 to 20, are exemplified by succinic acid, adipic acid, sebacic acid and dodecanedicarboxylic acid. 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-methylpropane-1,3-diol, methylpentanediol, and diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol and dibutylene glycol and polybutylene glycol. In order to obtain crystallinity, preferred alcohols are of the general formula HO-(CH 2 ) x An alcohol having -OH, wherein x is a number from 1 to 20, preferably an even number from 2 to 20. Examples of such alcohols are ethylene glycol, butane-1,4-diol, hexane-1,6-diol, octane-1,8-diol and dodecane-1,12-diol.

[0114] The diol (b1) may also 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 those skilled in the art.

[0115] The diol (b1) can also be a polyether diol. The polyether diol can in particular be obtained 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 admixture or continuously to an addition reaction with initiator components containing reactive hydrogen atoms, such as alcohols or amines, examples being water, ethylene glycol, propane-1,2-diol, propane-1,3-diol, 2,2-bis(4-hydroxyphenyl)propane and aniline. Polyether diols having a molecular weight of 500 to 5000 and in particular 600 to 4500 are particularly preferred.

[0116] The polyurethane of the polyurethane aqueous dispersion included in at least partially coated particles and shaped bodies according to the invention has a K value above 50 and below 100, preferably 55 to 95.

[0117] The K value is a relative viscosity value determined at 25 °C analogous to DIN EN ISO 1628-1 2021. It includes the flow rate of a 1 wt% concentration solution of the polyurethane in DMF relative to the flow rate of pure DMF and characterizes the average molecular weight of the polyurethane.

[0118] 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 ratio of mutually reactive monomers and the arithmetic mean of the number of reactive functional groups per molecule. Usually, components (a) to (e) and their respective molar amounts are selected such that the ratio A:B is 0.5:1 to 2:1, preferably 0.8:1 to 1.5:1, more preferably 0.9:1 to 1.2:1, where

[0119] A) is the molar amount of isocyanate groups, and

[0120] 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 as possible to 1:1.

[0121] The monomers (a) to (e) used usually carry on average 1.5 to 2.5, preferably 1.9 to 2.1, more preferably 2.0 isocyanate groups and / or functional groups capable of reacting with isocyanate 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.

[0122] The polyaddition of components (a) to (e) for the preparation of polyurethanes is preferably carried out at a reaction temperature of at most 180 °C, more preferably at most 150 °C, for example from 20 °C to 180 °C, preferably from 70 °C to 150 °C, under atmospheric pressure or under autogenous pressure. The preparation of polyurethanes and polyurethane aqueous dispersions is known to those skilled in the art. The polyaddition of the synthetic components for the preparation of polyurethanes can be catalyzed using organic or organometallic compounds. Suitable catalysts include dibutyltin dilaurate (DBTL), tin(II) octoate, tetrabutoxytitanium (TBOT) or diazabicyclo[2.2.2]octane. Other suitable catalysts are salts of cesium, especially cesium carboxylates, such as cesium formate, acetate, propionate, hexanoate or 2-ethylhexanoate.

[0123] The polyurethane aqueous dispersion 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 with 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 dihydroxy alcohols, diethylene glycol, triethylene glycol, polyethylene glycols having a number average molecular weight of at most about 3000, glycerol and dioxane, and ketones such as especially acetone. Preferably, the polyurethane dispersion is substantially free of organic solvents. Herein, "substantially free of organic solvents" means that the fraction of organic solvents is not more than 5% by weight, more preferably not more than 1% by weight, more particularly not more than 0.1% by weight, based on the total weight of the solvents.

[0124] Preferably, the polyurethane is prepared in the presence of at least one organic solvent. Preferred organic solvents for the preparation of polyurethanes 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 for the preparation of the polyurethane, the polyurethane dispersion of the present invention can also include the organic solvents used for the preparation in addition to water. It should be understood that the polyurethane dispersion of the present invention can be prepared in the presence of at least one organic solvent, which is then wholly or partly replaced by water.

[0125] A polyurethane dispersion can be prepared, for example, by one of the following methods: According to the "acetone process", an ionic polyurethane is prepared from synthetic components in a solvent that is miscible with water and boils below 100 °C at atmospheric pressure. Sufficient water is added to form a dispersion, where the water represents the cohesive phase. The "prepolymer mixing process" differs from the acetone process in that a prepolymer carrying isocyanate groups is prepared first, rather than a fully reacted (potentially) ionic polyurethane. In this case, the selected components are such that the determined ratio A:B is greater than 1.0 and at most 3, preferably 1.05 to 1.5. First, the prepolymer is dispersed in water, and then crosslinking is optionally carried out by reacting the isocyanate groups with an amine carrying more than 2 isocyanate-reactive amino groups, or chain extension is carried out by reacting the isocyanate groups with an amine carrying 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 remaining isocyanate groups in the prepolymer, accompanied by chain extension. Usually, if a solvent is also used during polyurethane preparation, most of the solvent is removed from the dispersion, for example, by vacuum distillation. The dispersion preferably has a solvent content of less than 10% by weight, and particularly preferably is solvent-free. The solvent is understood to mean an organic solvent.

[0126] Preferably, the polyurethane belonging to the polyurethane aqueous dispersion and included in at least partially coated particles and shaped bodies according to the invention is prepared from:

[0127] a) at least one organic diisocyanate selected from 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, and the amount of the aromatic diisocyanate is less than 60 mol-% based on the sum of all organic diisocyanates a),

[0128] b) at least one dihydroxy compound selected from the group consisting of polyester diols and polytetrahydrofuran,

[0129] c) at least one compound having at least one group reactive towards isocyanate groups and additionally carrying at least one ionic group or a group capable of being converted into an ionic group, wherein compound c) preferably contains a group selected from carboxylate groups and sulfonate groups,

[0130] d) optionally other compounds different from a) to c).

[0131] In the first step a of the process according to the invention 1) therein, the particles are brought into contact with a polyurethane aqueous dispersion, the polyurethane having a K value according to DIN EN ISO 1628-1 2021 in the range above 50 to below 100, preferably 55 to 95, thereby producing at least partially coated particles.

[0132] Preferably, in step a 1 ) therein, the contact is achieved by using a kitchen or cement mixer or spraying, such as mixing or spray-drying the expanded beads with the dispersion using a Vollrath mixer. The amount of liquid / suspension relative to the product weight can be in the range of 1 ml / kg / min to 1000 ml / g / min. The size of the droplets can vary between 1 mm and 1000 mm in diameter. Suitable nozzles will be hollow cone nozzles, full cone nozzles or flat jet nozzles as well as spraying disks that generate droplets by rotational movement and centrifugal force. A suitable mixer that can be used is the EMT 30L. EMT L 30 is a discontinuous paddle mixer. It is suitable for mixing, agglomerating and coating experiments. It consists of a rigid container with a rotatable mixing tool. Depending on the application area, there are various available mounting possibilities for the nozzles. Due to the double jacket, the mixer is heatable. The rotational speed can be adjusted by a mechanical transmission. Melt containers and pressure vessels are used for adding liquids.

[0133] Generally, common coating methods can be used, such as spraying, as described for example in EP 0 009 727 A1. In a preferred embodiment of the coating, the particles are sprayed and kept in motion by blowing air or a mixture of different gases, for example, against the particles.

[0134] The at least partially coated particles are coated in an amount of 0.1 wt.-% to 40 wt.-%, preferably 5 wt.-% to 25 wt.-%, based on the total weight of the particles and the 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%, and even more preferably completely coated, based on the total surface of the particles.

[0135] Step a 2 ) refers to drying the coated particles. In principle, all suitable methods are possible, such as convective drying, contact drying, infrared drying and microwave technology.

[0136] 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 can be N 2 or air. The gas amount is preferably 1 liter / minute - 1000 liters / minute per 1 kg of product, and the product temperature in the mixer should be between 1°C and 100°C, preferably 10°C to 60°C.

[0137] Preferably, during step a 2 ), at least some of the coated particles remain mobile. This can prevent agglomeration of the particles.

[0138] Preferably, after step a 1 ) and before step a 2 ), the particles are separated from each other. This can be achieved, for example, by using a vibrating belt or the like. This option also prevents agglomeration of the particles.

[0139] Another aspect of the present invention is a method for preparing a shaped body, the method comprising the following steps:

[0140] b 1 ) coating particles of an expandable thermoplastic elastomer according to the method of the present invention;

[0141] b 2 ) shaping the particles obtained from step b 1 ).

[0142] Preferably, the shaping in step b 2 ) is carried out by steamless hot pressing.

[0143] Preferably, the thermo-pressing / hot press / heat press is carried out at a temperature of 60°C to 160°C, more preferably 80°C to 160°C, even more preferably 90°C to 140°C, and even more preferably 90°C to 130°C.

[0144] Preferably, after shaping by hot pressing, the resulting shaped body is cooled to room temperature, which can improve the mechanical properties.

[0145] In one embodiment of the present invention, the molding (shaping) process can be carried out by using an electromagnetic field to generate the required heat completely or partially. The electromagnetic field is preferably in the range of 30 kHz to 1 GHz (corresponding to radio frequency (RF) and microwave molding) and more preferably in the range of 30 kHz to 300 MHz (corresponding to RF molding).

[0146] Thus, in a preferred embodiment, the shaping is carried out by heat, wherein the heat is generated partially or completely by an electromagnetic field in the range of 30 kHz to 1 GHz, preferably in the radio frequency range (30 kHz to 300 MHz).

[0147] Molding by energy 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. The microwave is preferably applied in a frequency range between 0.5 GHz and 100 GHz, particularly preferably in a range between 0.8 GHz and 10 GHz, and the irradiation time used is between 0.1 minute and 15 minutes. The radio wave is preferably applied in a frequency range between 500 kHz and 100 MHz, particularly preferably in a range between 1 MHz and 80 MHz, and the irradiation time used is between 0.1 minute and 30 minutes.

[0148] Preferably, the molded body is a composite material of the particles and other materials such as textiles, leather, thermoplastic films or metal-containing components.

[0149] Another aspect of the present invention relates to a method for disposing of a molded body, the method comprising the following steps:

[0150] c 1 ) Preparing a molded body according to the method of the present invention;

[0151] c 2 ) Decomposing the particles by subjecting the molded body to an alkaline aqueous fluid which may include a surfactant.

[0152] The at least partially coated particles according to the present invention can be used purely, as a mixture of different particles and / or other materials, to obtain 3D components for industrial, consumer, transportation and construction applications, which 3D components are used alone or as components for sealing, solar exposure of, for example, houses, pipes or gas tanks, shoe components, midsole, insole, combined sole, bicycle seat, bicycle tire, damping element, shock protection, sound and vibration damping, decoration, furniture, furniture decorative materials, mattress, yoga mat, cushioning layer, railway bedding, handle, protective sheet, packaging, fall protection, interior and exterior of automobiles, roof lining, armrest, door lining, seat, battery housing, sports equipment, ball, tennis racket, baseball club, treadmill, toy, floor, runway, artificial turf, sports field, stadium and sidewalk. Examples

[0153] Measuring the viscosity according to DIN EN ISO 3219-2:2021 at 23 °C and a shear rate of 250 s -1 The viscosity was measured at a shear rate of.

[0154] The dispersion was dried in a mold at 40 °C for 3 days and then at 23 °C for 7 days. The thermal properties were measured by differential scanning calorimetry.

[0155] The glass transition temperature determined according to DIN EN ISO 11357-2 (2014) is the so-called midpoint temperature. The glass transition temperature of the polymer in the polymer dispersion is the glass transition temperature evaluated from the second heating curve (heating rate 20 °C / min). The melting point and the enthalpy of fusion are determined according to DIN ISO 11357–3 (2018) (melting point = peak temperature) by heating at 20 K / min after cooling to -80 °C; the enthalpy of fusion for the second round (ΔH2) is calculated only from the area of the second melt;

[0156] a) From the film in the untreated state (dry, see above) → Tm1, ΔH1

[0157] b) After heating the polyurethane film to 130 °C, cool to -80 °C at 20 K / min; reheat at 20 K / min -> Tm2 ΔH2

[0158] Example 1: PUD according to Example 1 of WO 2012 / 13506A1

[0159] Repeat this example: s.c. 40%. K value: 55 Viscosity: 48 mPas Tg: -46 °C

[0160] Tm1 ΔH1 Tm2 ΔH2 47℃ 47 J / g 42.6 34 J / g

[0161] Example 2 :

[0162] React 676 g of a polyester diol (OH value 45) from adipic acid and 1,4-butanediol with 0.11 g of titanium tetrabutyrate, 40 g of IPDI, 0.77 g of an NCO-terminated polycarbodiimide (Elastostab H02, BASF) in 153 g of anhydrous acetone at 60 °C for 60 minutes. Then, add 37.8 g of HDI and raise the temperature to 74 °C. Continue the reaction until the NCO value is below 1.25%. Dilute the mixture with 539 g of acetone and cool to 35 °C - 40 °C. Then, add 22.4 g of sodium 2-aminoethylaminomethanesulfonate (50% in water) diluted with 22 g of demineralized water within 3 minutes, and then also add 4.6 g of isophoronediamine diluted with 23 g of demineralized water within 3 minutes. Before peptization, add 38.7 g of a 20% aqueous solution of Lutensol AT18 (BASF), then peptize with 463 g of demineralized water within 15 minutes, and immediately add 4 g of N-(2-aminoethyl)ethanolamine in 30 g of water and an additional 200 g of demineralized water within 15 minutes after the feed water. Remove the acetone by vacuum distillation with the aid of two drops of an antifoaming agent (modified polyalkylene glycol, FoamStar PB 2724, BASF), and adjust the solids content to 50%.

[0163] K value: 60 Viscosity: 169 mPas Tg: -55 °C

[0164] Tm1 ΔH1 Tm2 ΔH2 51℃ 54 J / g 46℃ 32 J / g

[0165] Example 3 :

[0166] React 541 g of a polyester diol (OH value 56) derived from adipic acid, 1,6 - hexanediol, and 1,4 - butanediol with 0.11 g of titanium tetrabutyrate, 40 g of IPDI, and 0.9 g of an NCO - terminated polycarbodiimide (Elastostab H02, BASF) in 153 g of anhydrous acetone at 60 °C for 60 minutes. Then, add 37.8 g of HDI and raise the temperature to 74 °C. Continue the reaction until the NCO value is below 1.47%. Dilute the mixture with 539 g of acetone and cool to 35 °C - 40 °C. Then, add 21.9 g of sodium aminoethylaminomethanesulfonate (50% in water) diluted with 22 g of demineralized water within 3 minutes, and then also add 4.6 g of isophoronediamine diluted with 23 g of demineralized water within 3 minutes. Before degumming, add 31.8 g of a 20% aqueous solution of Lutensol AT18 (BASF), and then degum with 361 g of demineralized water within 15 minutes. Immediately after the feed water, add 4 g of N - (2 - aminoethyl)ethanolamine in 30 g of water and an additional 200 g of demineralized water within 15 minutes. Remove acetone by vacuum distillation with the aid of two drops of an antifoaming agent (modified polyalkylene glycol, FoamStar PB 2724, BASF), and adjust the solid content to 50%.

[0167] K value: 66.5 Viscosity: 51 mPas Tg: -57 °C

[0168] Tm1 ΔH1 Tm2 ΔH2 24℃ 24 J / g 24℃ 21 J / g

[0169] Example 4 :

[0170] React 748 g of a polyester diol (OH value 45) derived from adipic acid and 1,4 - butanediol with 13.5 g of 1,4 - butanediol and 49.8 g of toluene diisocyanate (80 / 20 isomer mixture) in 309 g of anhydrous acetone at 65 °C in the presence of 0.2 g of tetrabutyl titanate as a catalyst until an NCO value of 0.2% is reached. Then, add 48 g of hexamethylene diisocyanate, followed by flushing with 58 g of anhydrous acetone. Continue the reaction until the NCO value is 0.95%. Dilute the mixture with 684 g of acetone and cool to 40 °C.

[0171] Chain extension was carried out with a 50% s.c. aqueous solution of 43.4 g of aminoethylaminosulfonic acid sodium salt within 10 minutes. Then, 4.4 g of Lutensol TO5 (ethoxylated, iso-C13 alcohol, BASF) dissolved in 12 g of water was added, followed by 726 g of deionized water. Acetone was removed by vacuum distillation, and during the distillation, two portions (2×0.1 g) of the antifoaming agent Foamstar PB 2724 (modified polyalkylene glycol) had to be added to control the foam. The solid content was adjusted to 45%.

[0172] K value 56 Viscosity: 19 mPas Tg: -54 °C

[0173] Tm1 ΔH1 Tm2 ΔH2 54.5℃ 46 J / g 43.5℃ 32 J / g

[0174] Example 5 :

[0175] 745 g (0.30 mol) of a polyester diol with an OH value of 45.2 (based on 1,4-butanediol / adipic acid), 13.4 g (0.10 mol) of dimethylolpropionic acid, 1.0 g of tetrabutyl orthotitanate (10% form), and 100 g of acetone were introduced as the initial charge, mixed with 112.3 g (0.505 mol) of isophorone diisocyanate at 60 °C, and stirred at 90 °C for 4 hours. Then, 900 g of acetone, 20.25 g of triisopropanolamine (0.09 mol), 5 g of carbodiimide (based on 1,3-bis(1-isocyanato-1-methylethyl)benzene, i.e., an isocyanate-terminated polymer) in 5 g of acetone (0.005 mol), 0.97 g of aminopropyltrimethoxysilane (0.005 mol), 31.35 g of aminoethylaminosulfonic acid sodium salt (0.075 mol), and 40 g of water were metered in successively, and the reaction mixture was stirred for another 20 minutes. It was dispersed in 1300 g of water; then acetone was distilled off under reduced pressure, and the solid content was adjusted to approximately 40%.

[0176] K value: 94 Viscosity: 120 mPas Tg: -53 °C

[0177] Tm1 ΔH1 Tm2 ΔH2 45.5℃ 39 J / g 44.4℃ 31.3 J / g

[0178] Example 6 :

[0179] React 726 g of a polyester diol (OH value 45) derived from adipic acid and 1,4-butanediol with 8.05 g of dimethylolpropionic acid (DMPA) and 67.3 g of hexamethylene diisocyanate in 80 g of anhydrous acetone at 90 °C until an NCO content of 0.52% - 0.47% is reached. Then dilute the mixture with 600 g of acetone and cool to 35 °C. Neutralize the mixture with 5.8 g of triethylamine and terminate the chain with 3.15 g of diethanolamine in 25 g of deionized water. After 10 minutes, disperse the mixture with 785 g of deionized water and stabilize it by adding 40 g of a 20% solution of Lutensol AT 18 (ethoxylated C16 / C18 alcohol, BASF). Remove the acetone by vacuum distillation and adjust the solids content to 50%.

[0180] K value: 55 Viscosity: 63 mPas Tg: -53 °C

[0181] Tm1 ΔH1 Tm2 ΔH2 56℃ 63 J / g 45℃；52℃ 60 J / g

[0182] Prepare 79.5 g of a dispersion with 0.1 g of Lumiten I-SC (a solution of sodium sulfosuccinate and ethoxylated isotridecanol in water, BASF) and 6 g of Aqualink U (a dispersion of blocked TDI dimer, Aquaspersion co., UK) to obtain a potentially reactive dispersion.

[0183] Example 7 :

[0184] React 563 g of a polyester diol (OH value 45) derived from adipic acid and 1,4-butanediol, 0.17 g of Borchikat 315 (a Wuxi catalyst, bismuth neodecanoate, Borchers) with 67.9 g of IPDI in 90 g of anhydrous acetone at 60 °C - 65 °C until an NCO value of 0.9% is reached. Dilute the mixture with 630 g of acetone and cool to 50 °C. Then, add 21.8 g of sodium aminoethylaminopropanesulfonate (50% in water) diluted with 22 g of demineralized water within 3 minutes. After 10 minutes, continue the dispersion with 927 g of deionized water. Remove the acetone by vacuum distillation with the aid of two drops of an antifoaming agent (modified polyalkylene glycol, FoamStar PB2724, BASF) and adjust the solids content to 40%.

[0185] K value 60 Viscosity: 121 mPas Tg: -53 °C

[0186] Tm1 ΔH1 Tm2 ΔH2 56.5℃ 46 J / g 40.3℃ 32 J / g

[0187] Example 8 :

[0188] React 563 g of a polyester diol (OH value 45) derived from adipic acid and 1,4 - butanediol with 0.08 g of Borchikat 315 (a Wuxi catalyst, bismuth neodecanoate, Borchers), 51.4 g of HDI in 90 g of anhydrous acetone at 60 °C - 65 °C until an NCO value of 0.96% is reached. Dilute the mixture with 630 g of acetone and cool to 50 °C. Then, add 21.8 g of sodium aminoethylaminomethanesulfonate (50% in water) diluted with 22 g of demineralized water within 3 minutes. After 10 minutes, continue the dispersion with 907 g of deionized water. Remove acetone by vacuum distillation with the aid of two drops of an antifoaming agent (modified polyalkylene glycol, FoamStar PB 2724, BASF) and adjust the solids content to 40%.

[0189] K value 65 Viscosity 50 mPas Tg: -54 °C

[0190] Tm1 ΔH1 Tm2 ΔH2 56℃ 56 J / g 49℃ 51 J / g

[0191] Example 9 :

[0192] React 332 g of a polyester diol (OH value 45) derived from adipic acid and 1,4 - butanediol and 271 g of poly - THF 2000 (OH value = 56 mg KOH / g) with 27.8 g of IPDI and 41.4 g of HDI at 100 °C in 60 g of anhydrous acetone for 6 hours. Dilute the mixture with 804 g of acetone and cool to 40 °C. Terminate the chain by adding a mixture of 3.55 g of diethanolamine, 0.82 g of N - (2 - aminoethyl)ethanolamine and 16 g of demineralized water. Then, add 18.7 g of sodium aminoethylaminomethanesulfonate (50% in water) diluted with 17 g of demineralized water within 3 minutes. After 10 minutes, continue the dispersion with 657 g of deionized water within 30 minutes. Remove acetone by vacuum distillation with the aid of two drops of an antifoaming agent (modified polyalkylene glycol, FoamStar PB 2724, BASF). To stabilize the dispersion, add 68.6 g of a 20% solution of Lutensol AT 18 (ethoxylated C16 / C18 alcohol, BASF) and adjust the solids content to 48%.

[0193] K value 57 Viscosity: 210 mPas Tg: -57 °C

[0194] Tm1 ΔH1 Tm2 ΔH2 18.4℃；53℃ 51 J / g 18.1℃、46℃ 39 J / g

[0195] Example 10 :

[0196] React 543 g of a polyester diol (OH value 56) derived from adipic acid, 1,6 - hexanediol, and 1,4 - butanediol with 27.12 g of IPDI and 40.4 g of HDI in 60 g of anhydrous acetone at 95 °C until an NCO value between 1.14% and 1.0% is reached. Dilute the mixture with 804 g of acetone and cool to 40 °C. Terminate the chain by adding a mixture of 3.55 g of diethanolamine, 0.83 g of N-(2 - aminoethyl)ethanolamine, and 16 g of demineralized water. Then, add 14.1 g of sodium 2 - aminoethylaminoethanesulfonate (50% in water) diluted with 17 g of demineralized water within 3 minutes. After 10 minutes, continue dispersion with 594 g of deionized water within 30 minutes. Remove acetone by vacuum distillation with the aid of two drops of an antifoaming agent (modified polyalkylene glycol, FoamStar PB 2724, BASF). To stabilize the dispersion, add 62 g of a 20% solution of Lutensol AT 18 (ethoxylated C16 / C18 alcohol, BASF) and adjust the solids content to 50%.

[0197] K value: 57 Viscosity: 59 mPas Tg: -57 °C

[0198] Tm1 ΔH1 Tm2 ΔH2 27.8℃、42℃ 42 J / g 27℃ 32 J / g

[0199] Example 11 :

[0200] React 1039 g of a polyester diol (molecular weight 2000 g / mol) derived from adipic acid and isophthalic acid (molar ratio 1:1) and 1,6 - hexanediol, 104.6 g of dimethylolpropionic acid (DMPA), 186.8 g of 1,4 - butanediol with 900 g of IPDI in 530 g of anhydrous acetone in a pressure reactor; start at 50 °C, raise the temperature to 90 °C within 30 minutes, and then continue at 90 °C under 2.9 bar for 8 hours. Dilute the mixture with 1852 g of acetone, cool to 40 °C, and expand to atmospheric pressure. Determine the NCO value to be 1.2%. Then, add 10.2 g of isophorone diamine in one portion, followed by 81 g of diethyl ethanolamine (neutralizing agent) within 5 minutes. After stirring for 5 minutes, continue the dispersion step with 3567 g of deionized water at 30 °C within 37 minutes, followed by adding 19.8 g of diethylenetriamine in 340 g of deionized water within 30 minutes. Remove acetone by vacuum distillation with the aid of 0.23 g of an antifoaming agent (FoamStar PB 2724, BASF), and the solids content is 37.4%.

[0201] Dispersion Ex11

[0202]

[0203] Example EX12 :

[0204] React 1024 g of a polyester diol from adipic acid and isophthalic acid (1:1 molar ratio) and 1,6 - hexanediol (molecular weight 2000 g / mol), 104.6 g of dimethylolpropionic acid (DMPA), 187 g of 1,4 - butanediol, and 72.8 g of side - chain polyethylene glycol Ymer N 120 (Perstorp) with 686.3 g of IPDI in 550 g of anhydrous acetone in a pressure reactor; start at 55 °C, feed IPDI, and raise the temperature to 75 °C within 30 minutes, then continue at 75 °C for 1.5 hours at 2.4 bar. Then, add a second portion of 228.8 g of IPDI and 18 g of acetone and continue the reaction until the NCO value is 2.2%. Dilute the mixture with 1574 g of acetone, cool to 40 °C, and expand to atmospheric pressure. The NCO value is determined to be 1.39%. Then, further dilute the mixture with 366 g of acetone, add 10.5 g of isophorone diamine in one portion, followed by 82.2 g of diethylethanolamine (neutralizing agent) within 5 minutes. After stirring for 10 minutes, continue the dispersion step with 3294 g of deionized water at 39 °C within 37 minutes, then add 19.8 diethylenetriamine in 346 g of deionized water within 30 minutes. Remove acetone by vacuum distillation with the aid of 0.58 g of an antifoaming agent (FoamStar PB 2724, BASF), and the solid content is 37%.

[0205] Dispersion Ex12

[0206]

[0207] Comparative Example C1: Amorphous dispersion

[0208] React 706 g of polypropylene glycol (OH value = 57.2 mg KOH / g) and 57.9 g of dimethylolpropionic acid (DMPA) with 137.9 g of toluene diisocyanate (80 / 20 isomer mixture) at 110 °C in 63 g of anhydrous acetone until an NCO content of <0.1% is reached. Then, dilute the mixture with 720 g of acetone and cool to 25 °C. Neutralize the mixture with 48.9 g of an aqueous NaOH solution (8 wt%) and disperse the mixture with 710 g of deionized water. Remove acetone by vacuum distillation with the aid of 3 drops of antifoaming agent Foam Star PB2724 (modified polyalkylene glycol, BASF), and adjust the solid content to 50%.

[0209] K value 43; no melting point or crystalline part could be detected

[0210] Comparative Example C2: Amorphous dispersion

[0211] React 801.4 g of polypropylene glycol (OH value = 56 mg KOH / g) and 64.4 g of dimethylolpropionic acid (DMPA) with 153.3 g of toluene diisocyanate (80 / 20 isomer mixture) in 100 g of anhydrous acetone at 100 °C - 110 °C until an NCO content of <0.1% is reached. Then, dilute the mixture with 800 g of acetone and cool to 50 °C. Neutralize the mixture with 19.4 g of triethylamine and disperse the mixture in 1580 g of deionized water. Remove the acetone by vacuum distillation and adjust the solids content to 40%.

[0212] The K value is 43, and no melting point or crystalline part can be detected.

[0213] Example 13: Coating e-TPU beads using a Vollrath dissolver

[0214] Mix the polyurethane dispersion described in Example 2 with E-TPU beads (granules) (Infinergy 230 based on diisocyanate 4, BDO, and polyol 1, manufactured by BASF SE) prepared according to Example 1 of WO2013 / 153190A1 using a Vollrath dissolver at room temperature for 60 seconds. Subsequently, dry the beads on a Teflon foil at room temperature, taking care to separate them from each other. Collect the beads after approximately 10 minutes. The beads are non-tacky and storage-stable.

[0215] Achieve different coating amounts. The beads contain 5% w / w to 20% w / w of the dispersion.

[0216] Mix, for example, 5 g of the coating with 95 g of E-TPU beads to obtain Sample 1 (coating with 5% dispersion).

[0217] Sample 1: E-TPU beads coated with 5% dispersion

[0218] Sample 2: E-TPU beads coated with 10% dispersion

[0219] Sample 3: E-TPU beads coated with 15% dispersion

[0220] Sample 4: E-TPU beads coated with 20% dispersion

[0221] Example 14: Coating e-TPU beads using a kitchen mixer

[0222] The polyurethane dispersion described in Example 2 was mixed with E-TPU beads (Infinergy 230 based on diisocyanate 4, BDO and polyol 1, BASF SE) having a bulk density of 130 g / l and a particle weight of 27 mg, manufactured according to Example 1 of WO2013 / 153190A1, using a kitchen mixer (Bosch) equipped with a dough hook. The beads were mixed until the water evaporated. For 100 g of the product, it took about 15 minutes until the particles were dry. This method produced non-sticky and storage-stable coated beads.

[0223] Example 15: Coating e-TPU beads using a kitchen mixer

[0224] The polyurethane dispersion described in Example 11 was mixed with E-TPU beads (particles) (Infinergy 230 based on diisocyanate 4, BDO and polyol 1, BASF SE) manufactured according to Example 1 of WO2013 / 153190A1 for 60 seconds at room temperature using a Vollrath dissolver. Subsequently, the beads were dried on a Teflon foil at room temperature, taking care to separate them from each other. The beads were collected after about 10 minutes. The beads were non-sticky and storage-stable.

[0225] Different coating amounts were achieved. There was 5% w / w to 20% w / w dispersion in the beads.

[0226] For example, 5 g of the coating was mixed with 95 g of E-TPU beads to obtain Sample 1 (coating with 5% dispersion).

[0227] Sample 1: E-TPU beads coated with 5% dispersion

[0228] Sample 2: E-TPU beads coated with 10% dispersion

[0229] Sample 3: E-TPU beads coated with 15% dispersion

[0230] Sample 4: E-TPU beads coated with 20% dispersion

[0231] Example 16: Coating e-TPU beads using a cement mixer equipped with a sieve drum

[0232] 2.75 kg of E-TPU beads (Infinergy 230 from BASF SE, based on diisocyanate 4, BDO and polyol 1) with a bulk density of 130 g / l and a particle weight of 27 mg, manufactured according to Example 1 of WO2013 / 153190A1, were placed in a cement mixer (model mix140) with a sieve drum from Scheppach. 481 g of the dispersion of Example 2 containing 1% blue dye was slowly added to the cement mixer under rotation. Within 90 seconds, the beads were completely coated. Then, the beads reached the sieve drum, enabling the separation of individual coated beads and collection on a bottom Teflon belt. Within 10 minutes after coating, the beads were non-sticky and could be collected and stored.

[0233] Example 17: Coating beads using a spray dryer device

[0234] 1.4 kg of E-TPU beads (manufactured according to Example 1 of WO2013 / 153190A1, with a bulk density of 130 g / l and a particle weight of 27 mg, Infinergy 230 from BASF SE, based on diisocyanate 4, BDO and polyol 1) were placed in a 30-liter paddle mixer from EMT GmbH (manufactured in 2013), where they were mixed at 100 rpm with Becker blades.

[0235] 150 g of the dispersion described in Example 2 was pumped via a gear pump at 3 bar to a nozzle with a diameter of 1.0 mm (manufacturer Spraying Systems), where it 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 while being coated at 100 rpm for 2 minutes at 20 °C. After the E-TPU beads had been coated, 1.0 kg / h of nitrogen was flushed into the mixer chamber at 20 °C via a separate tube with an inner diameter of 4 mm to increase the drying intensity by convective drying.

[0236] After drying for 7 hours, the pourable E-TPU beads were filled into plastic bags via a flap at the bottom of the mixer at a constant mixing speed of 100 rpm.

[0237] Example 18: Hot pressing experiment for realizing 3D parts with coated beads

[0238] 65 g of the coated beads according to Experiment 13 (Sample 3) were placed in a size (16.3×9.6×3.3) cm 3In a preheated mold of (length, brightness, depth), the mold was previously sprayed with Indrosil 2000 as a silicone-based release agent. The filled mold was covered with a mold lid (also sprayed with Indrosil 2000), which allowed 50% compression / compaction. The time in the heating press and the remaining time to cool the 3D part before demolding are summarized in the table below.

[0239] In addition, the tensile strength and elongation measured according to ASTM D5035:2011 in which (150×25.4×1.6) mm 3 e-TPU strips were used instead of fabric strips,

[0240] The resilience measured according to DIN 53512:2000-4 and the density of the obtained 3D part measured according to DIN EN ISO 845:2009-10 are also reported below.

[0241] For reference, 65 g of E-TPU beads with a bulk density of 130 g / l and a particle weight of 27 mg according to Example 1 of WO2013 / 153190A1 were placed in a mold of size (16.3×9.6×3.3) cm 3 (length, brightness, depth)). The filled mold was covered with a mold lid, which allowed 50% compression / compaction. This produced a plate with the following dimensions: (16×9.5×1.6) cm 3 - 3D parts molded by hot press of uncoated E-TPU beads that could be obtained were reported separately.

[0242]

[0243] Example 19 :

[0244] 65 g of coated beads (Sample 1) according to Experiment 15 were placed in a preheated mold of size (16.3×9.6×3.3) cm 3 (length, brightness, depth), and the mold was previously sprayed with Indrosil 2000 as a silicone-based release agent. The filled mold was covered with a mold lid (also sprayed with Indrosil 2000), which allowed 50% compression / compaction. The time in the heating press and the remaining time to cool the 3D part before demolding are summarized in the table below.

[0245] In addition, the tensile strength and elongation measured according to ASTM D5035:2011 in which (150×25.4×1.6) mm 3 e-TPU strips were used instead of fabric strips,

[0246] The rebound rate measured according to DIN 53512:2000-4 and the density of the obtained 3D components measured according to DIN EN ISO 845:2009-10 are also reported below.

[0247] For reference, 65 g of E-TPU beads with a bulk density of 130 g / l and a particle weight of 27 mg according to Example 1 of WO2013 / 153190A1 were placed in a preheated mold with dimensions (16.3×9.6×3.3) cm 3 (length, brightness, depth)). The filled mold was covered with a mold lid, which allowed 50% compression / compaction. This produced a plate with the following dimensions: (16×9.5×1.6) cm 3 - The 3D components obtained by hot press molding of uncoated E-TPU beads are reported separately.

[0248]

[0249] Example 20 :

[0250] 170 g of E-TPU beads (Infinergy 230 from BASF SE, based on diisocyanate 4, BDO and polyol 1) with a bulk density of 130 g / l and a particle weight of 27 mg according to Example 1 of WO2013 / 153190A1 and coated with 10 w / w% of the dispersion of Example 2 were placed in a cylinder with a diameter of 11 cm and a height of 15 cm. An 800 g weight was placed on the filled cylinder, and the cylinder was stored at room temperature.

[0251] After 10 days, the lid was removed and the coated particles were released. No agglomeration or caking was observed.

[0252] The same experimental setup was used to evaluate the agglomeration behavior of the coated beads over a period of 3 months. After 3 months of storage, the coated beads could also flow out without agglomeration.

[0253] For reference, 170 g of E-TPU beads according to WO2013 / 153190A1 (Infinergy 230 from BASF SE, based on diisocyanate 4, BDO and polyol 1) were placed in a cylinder with a diameter of 11 cm and a height of 15 cm. An 800 g weight was placed on the filled cylinder, and the cylinder was stored at room temperature for 10 days. When the lid was removed again, the beads did not flow out of the cylinder, and mechanical stirring was necessary to break up the agglomerates.

[0254] Therefore, the coated beads showed a positive phenomenon of avoiding agglomeration when stored under defined pressure.

[0255] Example 21 :

[0256] 50 g of E-TPU beads coated with 15 w / w% of the dispersion of Example 2 according to WO2013 / 153190A1, Example 1 (Infinergy 230 based on diisocyanate 4, BDO and polyol 1, BASF SE) were contacted with a Teflon foil. The coated beads were shaken for a period of 2 minutes in order to electrostatically charge them. Thereafter, the coated beads were allowed to flow off the Teflon foil and were collected in a wide-mouth bottle. No electrostatic charging of the beads was observed, and the coated beads could be easily removed from the Teflon carrier.

[0257] For reference, 50 g of E-TPU beads according to WO2013 / 153190A1 were contacted with a Teflon foil. The coated beads were shaken for a period of 2 minutes in order to electrostatically charge them. The E-TPU beads showed strong electrostatic charging and could not flow off the Teflon foil, but adhered to it without flowing away.

[0258] Thus, the coated beads show the advantage of avoiding electrostatic charging and can be used in applications where antistatic is not required.

[0259] Example 22 :

[0260] 60 g of the dispersion according to Experiment 2 were mixed with 20 g of Exolit AP 422 (from Clariant).

[0261] 200 g of E-TPU beads according to WO2013 / 153190A1, Example 1 were placed in a kitchen mixer (Bosch) equipped with a dough hook. The beads and the dispersion containing Exolit AP 422 were mixed for 10 minutes until the water was completely evaporated.

[0262] 65 g of the obtained coated beads were placed in a preheated mold of dimensions (16.3 × 9.6 × 3.3) cm 3 (length, brightness, depth), which was previously sprayed with Indrosil 2000 as a release agent. The filled mold was covered with a mold lid (also sprayed with Indrosil 2000), which allowed 50% compression / compaction. The time in the heating press and the remaining time for cooling the 3D part before demolding are summarized in the following table.

[0263]

[0264] This experiment shows that it is possible to include a flame retardant in the coating, and this results in 3D parts with good mechanical stability.

Claims

1. A method for producing storage-stable coated particles for moldable thermoplastic particle foams, the method comprising: The following steps are involved: a 1 ) contacting the particles with an aqueous polyurethane dispersion having a K value in the range of from above 50 to below 100, preferably from 55 to 95 according to DIN EN ISO 1628-1 2021, thereby producing at least partially coated particles; a 2 ) drying the coated particles.

2. The method of claim 1, wherein the moldable thermoplastic particle foam is an expanded thermoplastic elastomer.

3. The method of claim 2, wherein the expanded thermoplastic elastomer is an expanded thermoplastic polyurethane.

4. The process according to any one of claims 1 to 3, wherein the aqueous polyurethane dispersion has a solids content of at least 40 wt.-%, based on the total weight of the dispersion, preferably in the range of 45 wt.-% to 60 wt.-%, based on the total weight of the dispersion.

5. The method according to any one of claims 1 to 4, wherein the aqueous polyurethane dispersion has a hardness according to DIN EN ISO 3219-2:2021 at 23° C. and 250 s -1 The viscosity is less than 300 mPas, preferably less than 200 mPas at 23° C., measured at a shear rate of 1.5 %.

6. The method according to any of claims 1 to 5, wherein the polyurethane of the aqueous polyurethane dispersion has a glass transition temperature T according to DIN EN ISO 11357-2 (2014) of less than 0°C, preferably -10°C to -80°C, more preferably -20°C to -75°C, even more preferably -30°C to -70°C, even more preferably -40°C to -65°C, even more preferably -45°C to -60°C. g .

7. The method according to any one of claims 1 to 6, wherein the polyurethane has at least a first glass transition temperature T g1 and the second glass transition temperature T g2 , where T g1 Below 0℃ and T g2 Above 25℃.

8. The method according to any one of claims 1 to 7, wherein the polyurethane of the aqueous polyurethane dispersion has a melting temperature T in the range of 30° C. to 100° C., preferably 40° C. to 80° C. according to DIN EN ISO 11357-3 (2018). m .

9. The method according to any one of claims 1 to 8, wherein the polyurethane of the aqueous polyurethane dispersion is prepared by: a) is selected from the formula X(NCO) 2 at least one organic diisocyanate of a diisocyanate of the type a), wherein X is a non-cyclic aliphatic radical having 4 to 15 carbon atoms, an alicyclic hydrocarbon radical having 6 to 15 carbon atoms, an aromatic hydrocarbon radical having 6 to 15 carbon atoms or an aromatic aliphatic hydrocarbon radical having 7 to 15 carbon atoms, wherein the amount of the aromatic diisocyanate is less than 60 mol%, based on the sum of all organic diisocyanates a). b) at least one dihydroxy compound selected from the group consisting of polyester diols and polytetrahydrofuran, c) at least one compound having at least one group which is reactive toward isocyanate groups and which additionally carries at least one ionic group or one group which can be converted into an ionic group, wherein compound c) preferably contains a group selected from the group consisting of carboxylate groups and sulfonate groups, d) optionally further compounds different from a) to c).

10. The method of claim 9, wherein the aqueous polyurethane dispersion comprises at least one additive selected from the group consisting of ionic surfactants, nonionic surfactants, rheology modifiers, fillers, anti-blocking additives, other aqueous dispersions, crosslinkers, plasticizers, stabilizers against hydrolytic degradation, defoamers, and biocides.

11. The method according to any one of claims 1 to 10, wherein in step a 1 ), contact is achieved by mixing or spraying.

12. The method of any one of claims 1 to 11, 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 the particles and coating.

13. The method according to any one of claims 1 to 12, wherein in step a 2 ) during which at least a portion of the coated particles remain moving.

14. The method according to any one of claims 1 to 13, wherein in step a 1 ) and in step a 2 ), the particles are separated from each other in order to prevent the particles from agglomerating.

15. A method for producing a shaped body, the method comprising: The following steps are involved: b 1 ) Coating particles of an expanded thermoplastic elastomer according to the method of any one of claims 1 to 14; b 2 ) Make the 1 ) The particles obtained are shaped.

16. The method according to claim 15, wherein step b 2 ) wherein the forming is performed by steam-free hot pressing.

17. The method according to claim 16, wherein the hot pressing is carried out at a temperature of 60 to 160°C, preferably 80 to 160°C, more preferably 90 to 140°C, even more preferably 90 to 130°C.

18. A method according to any one of claims 15 to 17, wherein the forming is performed thermally, wherein the heat is generated partly or completely by an electromagnetic field in the range of 30 kHz to 300 MHz.

19. The method according to any one of claims 15 to 17, wherein the shaped body is a composite material of the particles with other materials such as textiles, leather, thermoplastic films or metal-containing parts.

20. A method for treating a shaped body, the method The following steps are involved: c 1 ) A shaped body prepared by the method according to any one of claims 15 to 19; c 2 ) decomposing the particles by subjecting the shaped body to an alkaline aqueous fluid.

21. Storage-stable at least partially coated particles of moldable thermoplastic particle foam, wherein the coating is a dried aqueous polyurethane dispersion and wherein the polyurethane has 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.

22. A shaped body comprising the storage-stable at least partially coated particles according to claim 21.

Images