WO2010010010A1

WO2010010010A1 - Thermoplastic polymer blends based on thermoplastic polyurethane and styrene polymer, foams produced therefrom and associated manufacturing methods

Info

Publication number: WO2010010010A1
Application number: PCT/EP2009/059014
Authority: WO
Inventors: Carsten Schips; Frank Braun; Frank Prissok
Original assignee: Basf Se
Priority date: 2008-07-25
Filing date: 2009-07-15
Publication date: 2010-01-28

Abstract

The invention relates to an expandable thermoplastic polymer blend containing foaming agents, said blend comprising thermoplastic polyurethane and a styrene polymer, optionally at least one other thermoplastic polymer, a method for manufacturing said thermoplastic polymer blend and a method for manufacturing foams based on thermoplastic polymer blends as well as foams produced by way of said methods.

Description

Thermoplastic polymer blends based on thermoplastic polyurethane and styrene polymer, foams produced therefrom and related manufacturing processes

description

The invention relates to an expandable, propellant-containing thermoplastic polymer blend comprising thermoplastic polyurethane (TPU) and styrene polymer, wherein preferably the weight percentages of thermoplastic polyurethane are between 5 and 95 and the weight proportions of styrene polymer are between 5 and 95 and the proportions by weight of thermoplastic polyurethane (TPU) and styrene polymer add to 100 parts, wherein the polymer blend contains in a preferred embodiment, at least one further thermoplastic polymer, and the sum of the proportions by weight of the thermoplastic polyurethane and the Styrolpoly- merisates in this preferred embodiment between 50 and 99 and the proportions by weight of thermoplastic polyurethane, styrene polymer and further thermoplastic polymer in this preferred embodiment add to 100 and the polymer blend is preferably present as granules. Moreover, the invention relates to processes for the preparation of the expandable, blowing agent-containing thermoplastic see polymer blend, in which the TPU and the styrene polymer, optionally together with at least one filler, auxiliary and additive, and / or at least one further thermoplastic polymer to a granulate extruded with a mean diameter of 0.2 mm to 1 cm, as well as processes for the production of foams based on thermoplastic polymer blends and the foams or thermoplastic polymer blends produced by these methods.

Further embodiments of the present invention can be taken from the claims, the description and the examples. It is understood that the features mentioned above and those explained below of the subject matter and method according to the invention can be used not only in the particular combination indicated, but also in other combinations, without departing from the scope of the invention.

Foams, especially particle foams, have long been known and widely described in the literature, e.g. in Ullmann's "Encyklopadie der technischen Chemie", 4th Edition, Volume 20, p. 416 ff.

In DE 4015714 A1 glass fiber reinforced TPU foams are mentioned, which are produced on an injection molding machine. Densities of 800 g / L and greater are specified in the examples. These are foamed TPU boards, not particle foams. Particle foams based on TPU are disclosed in WO 94/20568. A disadvantage of the TPU foams described in WO 94/20568 is the high energy consumption in the production and processing. It is applied a water vapor pressure of 4.5 bar to 7 bar, ie a temperature of 145 ° C to 165 ° C.

Furthermore, WO 94/20568 describes expanded, ie foamed, TPU particles which can be processed into shaped parts. These TPU foam particles are produced at temperatures of 150 ^° C. and above 150 ^° C. and in the examples have a bulk density of between 55 g / l and 180 g / l, which is disadvantageous during transport and storage of these particles because of the increased space requirement.

The object of the present invention was to find expandable, ie foamable, thermoplastic polymer particles with high expansion capacity, thereby low storage volume, and at the same time low propellant loss during storage and a suitable process for their preparation and to produce therefrom a particle foam, which at temperatures below 150 ⁰ C and at the same time has a high elasticity.

Surprisingly, this object has been achieved with a polymer blend comprising thermoplastic polyurethane (TPU) and styrene polymer, optionally containing at least one further thermoplastic polymer, and in that the polymer blend is processed into a foam using the processes according to the invention.

The invention relates to a thermoplastic particle foam which is produced from a polymer blend containing thermoplastic polyurethane, hereinafter referred to as TPU, and styrene polymer.

In a preferred embodiment, the polymer blend contains at least one further thermoplastic polymer in addition to TPU and styrene polymer. In preferred embodiments, this further thermoplastic polymer is selected from the group consisting of acrylonitrile-butadiene-styrene (ABS), polyamide (PA), polymethylmethacrylate (PMMA), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), cellulose and polyoxymethylene (POM). The generic terms of these groups also include mixtures of different representatives of this group. Thus, a polyamide can be composed of several polyamides having different properties, this applies equally to the TPU and styrene polymer contained in the polymer blend.

In further preferred embodiments, TPU, styrene polymer and the at least one further thermoplastic polymer are present in the mixture such that the proportions by weight of TPU, styrene polymer and the at least one further thermoplastic polymer add up to 100, the proportions by weight of the TPU and of the Styrene polymer together comprise between 50 parts by weight and 99 parts by weight, more preferably these parts by weight are between 70 and 99, more preferably between 80 and 99, even more preferably between 90 and 99, even more preferably between 95 and 99. In a particularly preferred embodiment Polymer blend as main components only TPU and styrene polymer before, preferably with at least one filler, auxiliary and / or additive. In other embodiments, the polymer blend is composed of thermoplastic polyurethane and at least one other thermoplastic polymer that is not styrene polymer. In an alternative embodiment, the polymer blend contains, in addition to styrene polymer, at least one further thermoplastic polymer which is not thermoplastic polyurethane.

In further preferred embodiments, the weight proportions of TPU and styrene polymer add up to 100 parts by weight, wherein the weight parts of TPU are between 5 and 95, more preferably between 15 and 85, more preferably between 30 and 70, particularly preferably between 40 and 60.

TPU and processes for their preparation have been described many times, for example Gerhard W. Becker and Dietrich Braun, Kunststoff Handbuch, Volume 7 "Polyurethane", Carl Hanser Verlag Munich Vienna 1993.

All molecular weights stated in this document, stated in [kg / mol], are the number average molecular weight.

In preferred embodiments, TPU is prepared by reacting from a mixture of isocyanates (a) with isocyanate-reactive compounds (b), preferably having a molecular weight of from 0.5 kg / mol to 10 kg / mol and optionally chain extenders (c), preferably one Molecular weight of 0.05 kg / mol to 0.5 kg / mol. In further preferred embodiments, at least one chain regulator (d), a catalyst (d) and optionally at least one filler, auxiliary and / or additive are added to the mixture for the production of TPU. The substance groups, which may also be indicated by the lower case letters, are also addressed as components.

The components (a), (b), (c), (d), (d) and (e) usually used in the preparation of the TPU are described below by way of example and comprise the following substance groups: isocyanates (a), in relation to isocyanates reactive compounds (b), chain extenders (c), chain regulators (d), catalysts (d) and / or at least one customary filling, auxiliary and / or additive.

In any case, a mixture of isocyanates (a) and isocyanate-reactive compounds (b) is required for the preparation of TPU. The further addition of the Components (c), (c1), (d) and (e) are optional and may be alone or in all possible variations. In this case, component means in each case a single substance or a mixture of the substances belonging to this component. The components isocyanates (a), isocyanate-reactive compounds (b), and chain extenders (c) and, if used, the chain regulators (c1) are addressed as structural components.

In preferred embodiments, the organic isocyanates used are (a) aliphatic, cycloaliphatic, araliphatic and / or aromatic isocyanates, further preferred diisocyanates. Examples of preferred diisocyanates are tri-, tetra-, penta-, hexa-, hepta- and / or octamethylene diisocyanate, 2-methylpentamethylene diisocyanate 1, 5, 2-ethyl-butylene-diisocyanate-1, 4, Pentamethylene diisocyanate 1, 5, butylene diisocyanate 1, 4, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl cyclohexane (isophorone diisocyanate, IPDI), 1, 4 and / or 1, 3-bis (isocyanatomethyl) cyclohexane (HXDI), 1, 4-cyclohexane diisocyanate, 1-methyl-2, 4- and / or -2, 6-cyclohexane diisocyanate and / or 4,4'-, 2,4 '- and 2,2'-dicyclohexylmethane diisocyanate, 2,2'-, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1, 5-naphthylene diisocyanate (NDI), 2,4- and / or 2,6-tolylene diisocyanate (TDI), diphenylmethane diisocyanate, 3,3'-dimethyl-diphenyl-diisocyanate, 1, 2-diphenylethane diisocyanate and phenylene diisocyanate.

As isocyanate-reactive compounds (b), in preferred embodiments polyesterols, polyetherols and / or polycarbonate diols, which are usually also grouped together under the term "polyols", are used.

TPU is preferably prepared from polyether alcohol, polyetherdiol is particularly preferably used. A particularly preferred polyether diol is polytetrahydrofuran. The polyether alcohols and polytetrahydrofuran having a molecular weight between 0.6 kg / mol and 2.5 kg / mol are preferably used. The polyether alcohols are used individually or else as a mixture of different polyether alcohols.

In alternative embodiments, TPU is made from polyester alcohol. In a preferred embodiment, polyester diol is used for this purpose. A preferred polyester diol is prepared from adipic acid and butane-1, 4-diol. Preferred embodiments of the polyester alcohols have a molecular weight between 0.6 kg / mol and 2.5 kg / mol.

In further preferred embodiments, these polyols have molecular weights of 0.5 kg / mol to 8 kg / mol, preferably 0.6 kg / mol to 6 kg / mol, in particular 0.8 kg / mol to 4 kg / mol, and in further preferred embodiments have an average functionality of from 1.8 to 2.3, more preferably from 1.9 to 2.2, in particular 2. In a particularly preferred embodiment, the polyol is a polyester alcohol, preferably from polyether tetrahydrofuran, and in a further preferred embodiment has a molecular weight between 0.6 kg / mol and 2.5 kg / mol

As chain extenders (c), in preferred embodiments, aliphatic, aromatic, aromatic and / or cycloaliphatic compounds are used, which in further preferred embodiments have a molecular weight of from 0.05 kg / mol to 0.5 kg / mol. In some preferred embodiments, chain extenders (c) are compounds having two functional groups, for example diamines and / or alkanediols having 2 to 10 C atoms in the alkylene radical, in particular butanediol-1, 4, hexanediol-1, 6 and / or Di, tri, tetra, penta, hexa, hepta, octa, nona and / or Dekaalkylenglykole having 3 to 8 carbon atoms and corresponding oligo- and / or polypropylenglykole. In further embodiments, mixtures of the chain extenders are used to prepare TPU.

In some embodiments, chain regulators (d), usually having a molecular weight of 0.03 kg / mol to 0.5 kg / mol, are used. Chain regulators are compounds which have only one functional group compared to isocyanates. Examples of chain regulators are monofunctional alcohols, monofunctional amines, preferably methylamine, and / or monofunctional polyols. Through chain regulators, the flow behavior of the mixtures of the individual components can be specifically adjusted. Chain regulators are in preferred embodiments in an amount of 0 parts by weight to 5 parts by weight, more preferably from 0.1 parts by weight to 1 parts by weight, based on 100 parts by weight of the isocyanate-reactive compound b) used. Chain regulators are used in addition to or instead of chain extenders.

In further embodiments, at least one catalyst (d) is used for TPU preparation, which accelerates in particular the reaction between the NCO groups of the diisocyanates (a) and the isocyanate-reactive compounds, preferably hydroxyl groups of the synthesis components (b), (c) and d , In preferred embodiments, the catalyst is selected from the group of tertiary amines such as triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N, N'-dimethylpiperazine, 2- (dimethylaminoethoxy) ethanol, diazabicyclo (2,2,2) octane and similar substances. In further preferred embodiments, the at least one catalyst is selected from the group of organic metal compounds and is, by way of example, titanic acid ester, an iron compound such as iron (Ml) - acetylacetonate, a tin compound, eg Zinndiacetat, Zinndioctoat, tin dilaurate or a Zinndialkylsalz an aliphatic Carboxylic acid such as dibutyltin diacetate, dibutyltin dilaurate or the like. In some embodiments, the catalysts are used individually, in other embodiments, mixtures of catalysts are used. In preferred embodiments, the catalyst or mixture of catalysts is in from 0.0001 parts by weight to 0.1 parts by weight per 100 parts by weight of the isocyanate-reactive compound (b), preferably polyhydroxyl compound.

Examples of auxiliary and / or additive (s) include hydrolysis protectants and flame retardants. Other additives and auxiliaries may be standard works such as o.g. Becker and Braun (1996).

In addition to catalysts (d), but also without the use of catalysts, structural components (a) to (c) and, if appropriate, (d) can also be added to hydrolysis protection agents such as, for example, polymeric and low molecular weight carbodiimides.

In a further embodiment, the TPU may contain a phosphorus compound. In a preferred embodiment, organophosphorus compounds of the trivalent phosphorus, such as, for example, phosphites and phosphonites, are used as the phosphorus compounds. Examples of suitable phosphorus compounds are triphenylphosphite, diphenylalkylphosphite, phenyldialkylphosphite, tris (nonylphenyl) phosphite, trilaurylphosphite, trioctadecylphosphite, di-stearyl-pentaerythritol diphosphite, tris (2,4-di-tert-butylphenyl) phosphite, diisodecylpentaerythritol diphosphite, di- (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis (2,4-di-tert-butylphenyl) 4,4'-diphenylylenediphosphonite, trisisodecyl phosphite, diisodecylphenyl phosphite and diphenylisodecyl phosphite or mixtures thereof.

Particularly preferred embodiments contain phosphorus compounds which are difficult to hydrolyze since the hydrolysis of a phosphorus compound to the corresponding acid can lead to damage of the polyurethane, in particular of the polyester urethane. Accordingly, phosphorus compounds are particularly suitable for polyester urethanes, which are particularly difficult to hydrolyze. Preferred embodiments of hardly hydrolyzable phosphorus compounds are di-propylene glycol phenyl phosphite, tri-isodecyl phosphite, triphenyl monodecyl phosphite, trisisononyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tetrakis (2,4-di-tert-butylphenyl) 4,4 ' -diphenylylenediphosphonite and di- (2,4-di-tert-butylphenyl) -pentaerythritol diphosphite or mixtures thereof.

To adjust the Shore hardness of TPU, the structural components (b) and (c) can be varied in relatively wide molar ratios. In preferred embodiments, the molar ratio of component (b) to total chain extender (c) used is from 10: 1 to 1:10, preferably from 5: 1 to 1: 8, more preferably from 1: 1 to 1: 4 the hardness of TPU increases with increasing content of chain extender (c). In this way, Shore hardnesses of A44 to D80 can be adjusted, particularly preferred are Shore hardnesses of A44 to A84. The Shore hardnesses are determined according to DIN 53505. In further preferred embodiments, the conversion to TPU takes place with customary characteristic numbers. The index is defined by the ratio of the total isocyanate groups of component (a) used in the reaction to the isocyanate-reactive groups, ie the active hydrogens, components (b) and (c). With a figure of 100, an isocyanate group of component (a) has an active hydrogen atom, ie, an isocyanate-reactive function, components (b) and (c). In the case of characteristic numbers above 100, more isocyanate groups than groups reactive toward isocyanates, for example OH groups, are present. In particularly preferred embodiments, the conversion to TPU is carried out at a ratio between 60 and 120, more preferably at a ratio between 80 and 1 10.

The production of TPU is preferably carried out according to one of the known methods mentioned below. Preferred embodiments are the continuous process, for example with reaction extruders, the belt process, the one-shot process or the prepolymer process. [Ebenfalls Ebenfalls] Preferred embodiments are also the batch process or the prepolymer process process. a) and (b) and optionally (c), (d), (d) and / or (e) are mixed successively or simultaneously with each other, the reaction of the components (a) and (b) being used immediately.

In the extruder process, the synthesis components (a) and (b) and optionally components (c), (d), (d) and / or (e) are introduced individually or as a mixture into the extruder and at temperatures of 100 ⁰ C to 280 ⁰ C, preferably at 140 ⁰ C to 250 ⁰ C reacted. The resulting TPU is extruded, cooled and granulated. Optionally, it may be appropriate to heat the resulting TPU before further processing at 80 ° C to 120 ° C, preferably at 100 ° C to 1 10 ° C over a period of 1 to 24 hours, ie the mixture at a constant temperature the possibility to give further to respond.

By styrene polymer is meant any polymer based on a styrene monomer. The styrene polymer is selected in preferred embodiments from the group: standard polystyrene, impact polystyrene (HIPS), styrene-acrylonitrile copolymers (SAN), acrylonitrile-butadiene-styrene copolymers (ABS), alpha-methyl-styrene-acrylonitrile (AMSAN) and acrylonitrile-styrene-acrylic ester (ASA). Particular preference is given to using styrene-acrylonitrile copolymer (SAN) or acrylonitrile-butadiene-styrene copolymers (ABS) or mixtures of these two styrene polymers. In preferred embodiments, styrene-acrylonitrile copolymers (SAN) and acrylonitrile-butadiene-styrene copolymers (ABS) having weight average molecular weights in the range of 100 kg / mol to 250 kg / mol are used. Further preferred are the styrene polymers a viscosity number (in 0.5% DMF) measured according to DIN 53726 in the range from 50 mL / g to 100 mL / g, in particular also SAN and ABS.

The preparation and processing of the styrene polymers are extensively described in the literature, e.g. in the Kunststoff-Handbuch Volume 4, "Polystyrene", by Becker / Braun (1996).

At least one further polymer, which is thermoplastic in a preferred embodiment, is added to the polymer blend of styrene polymer and TPU according to the invention in preferred embodiments. In principle, any polymer miscible with the polymer blend consisting of styrene polymer and TPU can be added. Particularly preferred polymers are polyamide (PA), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), cellulose and / or polyoxymethylene (POM).

The addition of the at least one further polymer is carried out in preferred embodiments in amounts of 0.1% by weight to 70% by weight, preferably 0.1% by weight to 50% by weight, more preferably 0.1% to 30% by weight. , more preferably 0.1% by weight to 20% by weight, more preferably 0.1% by weight to 15% by weight, more preferably 0.1% by weight to 10% by weight, and particularly preferably 0.1% by weight. % to 5 wt.% Based on the total weight of the polymer blend without the addition of the filler, auxiliary and / or additive.

The constituents TPU, styrene polymer and further thermoplastic polymer may furthermore each contain, individually or in admixture, at least one filler, auxiliary and / or additive.

Usual additives or excipients as well as suitable additional amounts are to be taken from the usual technical literature. By way of example, mention may be made of the Kunststoffhandbuch, Volume VII, edited by Vieweg and Hochtlen, Carl Hanser Verlag, Munich 1966 (S 103-1 13). In preferred embodiments, these are surface-active substances, athermic substances, bacteriostats, inorganic and / or organic fillers, Flame retardants, fungicides, compatibilizers, nucleating agents, oxidation stabilizers, other stabilizers, eg against hydrolysis, light, heat or discoloration, lubricants and mold release agents, dyes and pigments, optionally additionally lent inorganic and / or organic fillers, reinforcing agents and plasticizers.

As surface-active substances z. For example, compounds which serve to assist the homogenization of the starting materials and, if appropriate, are also suitable for regulating the cell structure. Examples include emulsifiers, such as. As the sodium salts of castor oil or of fatty acids and salts of fatty acids with amines, eg. Diethylamine, stearic acid diethanolamine, ricinoleic diethanolamine, salts of sulfonic acids, eg. As alkali or ammonia salts of dodecylbenzene- or dinaphthylmethanedisulfonic acid and ricinoleic acid; Foam stabilizers, such as siloxane-oxalkylene copolymers and other organosiloxanes, ethoxylated alkylphenols, ethoxylated fatty alcohols, paraffin oils, castor oil or ricinoleic acid esters, turkey red oil and peanut oil and cell regulators, such as paraffins, fatty alcohols and dimethylpolysiloxanes. To improve the emulsifying effect, the cell structure and / or their stabilization, oligomeric polyacrylates having polyoxyalkylene and fluoroalkane radicals as side groups are also suitable. The surface-active substances are usually used in amounts of from 0.01 to 5 parts by weight, based on 100 parts by weight of the relatively high molecular weight polyhydroxyl compounds (b) (without consideration of mixed magnetisable particles).

Suitable flame retardants are, for example, tricresyl phosphate, tris (2-chloroethyl) phosphate, tris (2-chloropropyl) phosphate, tris (1, 3-dichloropropyl) phosphate, tris (2,3-dibromopropyl) phosphate and tetrakis. (2-chloroethyl) ethylene diphosphate. In addition to the previously mentioned halogen-substituted phosphates and inorganic

Flame retardants such as red phosphorus, alumina hydrate, antimony trioxide, arsenic trioxide, ammonium polyphosphate and calcium sulfate or cyanuric acid derivatives, such as. As melamine or mixtures of at least two flame retardants, such as. For example, ammonium phosphates and melamine and optionally starch and / or expandable graphite for flameproofing the cellular PU elastomers according to the invention can be used. In general, it has proven expedient to 5 to 50 parts by weight, preferably 5 to 25 parts by weight of said flame retardants or - mixtures for every 100 parts by weight of the structural components (a) to (c), wherein the Weight of possibly mixed magnetisable particles is not taken into account.

As a nucleating agent z. As talc, calcium fluoride, sodium phenylphosphinate, alumina and finely divided polytetrafluoroethylene in amounts up to 5 wt .-%, based on the total weight of the structural components (a) to (c), wherein the weight of any admixed magnetizable particles is not taken into account , Suitable antioxidants and heat stabilizers which can be added to the cellular PU elastomers according to the invention are, for example, halides of Group I metals of the periodic system, e.g. For example, sodium, potassium, lithium halides, optionally in combination with copper (l) halides, eg. As chlorides, bromides or iodides, hindered phenols, hydroquinones, and substituted compounds of these groups and mixtures thereof, which are preferably used in concentrations up to 1 wt .-% based on the weight of the structural components (a) to (c) , Examples of hydrolysis protectants are various substituted carbodiimides, such as 2,2 ', 6,6'-tetraisopropyldiphenylcarbodiimide, which are generally present in amounts of up to 2.0% by weight, based on the weight of the constituent components (a) to (c). , Wherein the weight of possibly admixed magnetisable particles is not taken into consideration, can be used. Lubricants and mold release agents used in the also in amounts of up to 1% by weight, based on the weight of the constituent components (a) to (c), wherein the weight of possibly admixed magnetizable particles is not taken into account, are stearic acid, stearyl alcohol, stearic acid esters and amides and the fatty acid esters of pentaerythritol. Furthermore, organic dyes, such as nigrosine, pigments, such as. As titanium dioxide, cadmium sulfide, cadmium sulfide selenide, phthalocyanines or ultramarine blue are added. Further, microbial inhibitors and / or organic colorants may be added. Further, athermane materials such as graphite, carbon black or aluminum powder may be added.

Preferred embodiments of the polymer blend contain as fillers organic and inorganic powders or fibrous materials, as well as mixtures thereof. Examples of organic fillers are wood flour, starch, flax, hemp, ramie, jute, leather, sisal, cotton, cellulose or aramid fibers. Preferred embodiments with inorganic fillers are selected from the following group: silicates,

Barite, glass beads, zeolites, metals, metal oxides or pulverulent inorganic substances, such as talc, chalk, kaolin (Ab ^ Os) (OH) ₄ ), aluminum hydroxide, magnesium hydroxide, aluminum nitrite, aluminum silicate, barium sulfate, calcium carbonate, calcium sulfate, silicic acid, quartz powder , Aerosil, alumina, mica or wollastonite and spherical or fibrous inorganic substances such as iron powder, glass beads, glass fibers or carbon fibers. The average particle diameter or, in the case of fibrous fillers, the mean length is in preferred embodiments in the range of the cell size of the expanded granulate or of the molded foam or is smaller. Preferred embodiments contain fillers having an average particle diameter in the range from 0.1 μm to 100 μm, more preferably in the range from 1 μm to 50 μm. In the components A and / or B, contents of fillers between 5% by weight and 80% by weight are preferred, inorganic and / or organic fillers being used. Further details of the above-mentioned other customary fillers, auxiliaries and additives can be found in the specialist literature, see, for example, Kunststoffhandbuch, Volume VII, edited by Vieweg and Hochtlen, Carl Hanser Verlag, Munich 1966 (S103-1 13).

The thermoplastic polymer blends are used according to the invention for the preparation of expandable, preferably particulate and more preferably propellant-containing thermoplastic polymer blends, furthermore for the production of expanded thermoplastic polymer blends and for the production of molded foam based on thermoplastic polymer blends. The preparation of these materials from the thermoplastic polymer blends is described below. The expanded thermoplastic polymer blend particles according to the invention can in principle be prepared by suspension or extrusion processes directly or indirectly via expandable particles of polymer blend and foaming in a pressure prefoamer with steam or hot air.

In a preferred embodiment, the suspension process, the polymer blend is used as granules, more preferably as minigranules having an average diameter of 0.2 mm to 1 cm, in particular from 0.5 mm to 5 mm. In further preferred embodiments, the minigranule is cylindrical or round and is prepared by extruding the polymer blend, in a preferred embodiment with at least one filler, auxiliary and / or additive, then extruding from the extruder, optionally cooling, and granulating. The granules are heated with water, a suspension aid and the blowing agent in a closed reactor to above the softening temperature of the granules. In this way, the propellant penetrates into the granules. This process is also referred to as impregnating the polymer particles with blowing agent. In one embodiment, the hot suspension is cooled, whereby the particles solidify to include the blowing agent, and then the reactor is expanded. The blowing agent-containing expandable particles obtained in this way expand upon heating, resulting in expanded particles having a foam structure. In an alternative embodiment, the hot suspension is suddenly expanded without cooling (explosion expansion process), wherein the softened, blowing agent-containing particles foam directly to the expanded particles. This method is i.a. disclosed in WO 94/20568.

In the extrusion process, the polymer blend is melt-mixed in an extruder with a blowing agent supplied to the extruder under pressure. In one embodiment, the polymer blend is used as premixed granules consisting of TPU and styrene polymer, optionally with at least one further thermoplastic polymer. In other embodiments, the polymer blend of the present invention is made in-situ in the extruder from TPU and styrene polymer, and in a preferred embodiment with at least one other thermoplastic polymer In a further alternative embodiment, the polymer blend of the invention is formed from the TPU components (a), (b), (c), (d), (d) and (e) and styrene polymer and, in a preferred embodiment, with at least one further thermoplastic polymer The propellant-containing mixture is either in an environment with such Pressed and temperature conditions pressed and granulated that the granules of the polymer blend does not foam, so does not expand.This can be achieved for example by an underwater granulation, which is operated at a water pressure of more than 2 bar low temperature propellant-containing, expandable particles, which by anschlie gently heating the expanded particles to be foamed. In a Alternatively, the mixture is squeezed out into an environment without overpressure. This results in a foaming of the expandable polymer blend. In a preferred embodiment, this foaming takes place by pressing the blowing agent-containing melt through a corresponding nozzle, so that directly expanded plates of the desired size are formed from the expandable polymer blend.

In a further embodiment, the melt is pressed through a suitable nozzle. In the process, the melt strand pressed out of the extruder foams up and solidifies. The expanded particles are obtained by subsequent granulation of the expanded melt strand.

The expandable particles of thermoplastic polymer blend according to the invention are preferably prepared by the suspension process or by the extrusion process.

Depending on the method used, the preferred blowing agents vary. In the suspension process is preferably used as a propellant organic liquids or inorganic gases or mixtures thereof. In some embodiments, the organic liquids are halogenated hydrocarbons, but preferred are saturated aliphatic hydrocarbons, especially those having 3 to 8 carbon atoms.

Atoms. Preferred inorganic gases are nitrogen, air, ammonia or carbon dioxide.

In the production on the extrusion process is used as the blowing agent loading vorzugt volatile organic compounds having a boiling point of -25 ⁰ C to

150 ⁰ C at atmospheric pressure (1013 mbar), more preferably, this boiling points is between -10 ⁰ C and 125 ⁰ C. Preferred blowing agents are hydrocarbons (preferably halogen-free), in particular C4-io-alkanes, for example, the isomers of butane, pentane , Hexanes, heptanes and octanes, particularly preferred is s-pentane. Suitable propellants are also compounds such as alcohols, ketones, esters, ethers and organic carbonates. In some embodiments, the organic liquids are halogenated hydrocarbons, but preferred are saturated aliphatic hydrocarbons, especially those having 3 to 8 carbon atoms. Preferred inorganic gases are nitrogen, air, ammonia or carbon dioxide.

In other embodiments, halocarbons are used as blowing agents, but preferably the blowing agent is halogen-free. However, small proportions of halogen-containing blowing agents are not excluded in practice in the blowing agent mixture. In further embodiments, any desired mixtures of the stated blowing agents are also used. In preferred embodiments, the blowing agent amount is 0.1 to 40 parts by weight, in particular 0.5 parts by weight to 35 parts by weight and particularly preferably 1 to 30 parts by weight, based on 100 parts by weight of polymer used -Blend.

The suspension process is usually carried out batchwise in an impregnation vessel, e.g. in a stirred tank reactor. In the reactor, the polymer blend are metered in as granules, also water or another suspension medium, and the blowing agent and optionally a suspension aid. In preferred embodiments, the suspension aid used is at least one water-insoluble inorganic stabilizer, such as tricalcium phosphate, magnesium pyrophosphate, metal carbonate; also used polyvinyl alcohol and surfactants such as sodium dodecylarylsulfonate. The stabilizer is used as a single substance or in mixtures, in preferred embodiments in amounts of from 0.01% by weight to 10% by weight, based on the polymer blend.

Thereafter, the reactor is closed and the reactor contents are heated to an impregnation temperature, in a preferred embodiment this is from 100 ^° C. to 150 ^° C. The propellant is added before, during or after the reactor contents have been heated. In a preferred embodiment, the impregnation temperature is in the vicinity of the softening temperature of the polymer blend. Preferred impregnation temperatures are between 100 ° C and 200 ⁰ C, in particular between 110 ° C and 145 ° C. Depending on the type and amount of propellant and the height of the temperature in the closed reactor vessel, a pressure is set, which is in preferred embodiments between 2 bar and 100 bar (absolute). In further preferred embodiments, the pressure is regulated by a pressure regulating valve or by repressing propellant. At these impregnation conditions, blowing agent diffuses into the polymer granules particles. The impregnation time is preferably between 0.5 hours and 10 hours.

In a preferred embodiment of the suspension process, the impregnated suspension is cooled to below 100 ⁰ C, whereby the polymer blend solidifies again and includes the blowing agent. After solidification of the polymer blend is relaxed. Thus one obtains expandable particles of polymer blend, which are separated from the suspension, for example by a sieve. Adhesive water is removed in a preferred embodiment by drying, for example in a stream dryer.

If necessary, in other embodiments, before or after drying, the adhering suspension aid is removed by treating the particles with a suitable reagent. In a further preferred embodiment, the polymer blend is mixed with an acid such as nitric acid, hydrochloric acid or sulfur. acid to remove acid-soluble suspension aids, such as metal carbonates or tricalcium phosphate.

In the extrusion process, the extruder TPU and styrene polymer, the blowing agent and optionally at least one filler, auxiliary and / or additive, in a preferred embodiment, at least one thermoplastic polymer, in common, as a mixture or separately, at one or at different locations supplied to the extruder. In this case, in an optional embodiment, a mixture is prepared from the solid components. In one embodiment, first of all TPU and styrene polymer and, if appropriate, filler, auxiliary and / or additive (s), and in a preferred embodiment, at least one further thermoplastic polymer are mixed and the mixture is fed to the extruder, then the blowing agent is fed to the extruder ie the extruder mixes the blowing agent into a polymer melt. In an alternative embodiment, a mixture of blowing agent and fillers, auxiliaries and / or additives is fed to the extruder, i. the fillers, auxiliaries, and / or additives are added first with the propellant.

In the extruder, the starting materials mentioned are mixed with melting. Suitable extruders are all conventional screw machines, in particular single screw and twin screw extruders (eg type ZSK from Werner & Pfleiderer), co-kneaders, Kombiplast machines, MPC kneading mixers, FCM mixers, KEX kneading screw extruders and Shear roll extruder, as described, for example, in Saechtling (ed.), Kunststoff-Taschenbuch, 27th edition, Hanser-Verlag, Munich 1998, chap. 3.2.1 and 3.2.4 are described. The extruder is preferably operated at a temperature at which the polymer blend is present as a melt, for example at 150 ⁰ C to 250 ⁰ C, particularly at 180 ° C to 210 ⁰ C.

The speed, length, diameter and configuration of the extruder screw (s), supplied quantities and extruder throughput are selected by the person skilled in the art such that the fillers, auxiliaries and / or additives are uniformly distributed in the extruded polymer blend.

In one embodiment of the extrusion process, expandable particles are produced. In order to prevent the propellant-containing melt from foaming on exiting the extruder, the temperature and pressure conditions are coordinated so that the melt strand practically does not foam up (expands) during extrusion. These conditions depend on the type and amount of the polymers, the fillers, auxiliaries, and / or additives and in particular the blowing agent. The expert routinely determines the optimum conditions by means of appropriate preliminary tests. A technically advantageous embodiment is the underwater granulation in a water bath, which has a temperature below 100 ⁰ C and under a pressure of at least 2 bar (absolute). The temperature range results in practice from two limit parameters. On the one hand, depending on the material properties, the temperature must be set so high that the melt on the nozzle plate does not solidify, and at the same time, it must be chosen so low that the melt does not expand.

The higher the boiling point of the propellant and the lower the amount of propellant, the higher the water temperature and the lower the water pressure can be. In a preferred embodiment with the propellant s-pentane is the optimum water bath temperature at 30 ⁰ C to 60 ⁰ C and the optimum water pressure at 8 bar to 12 bar (absolute).

In some embodiments, other suitable cooling media are used instead of water. In another embodiment, water ring granulation is used. In this case, the cutting space is encapsulated in such a way that the granulating device can be operated under pressure.

In this way, expandable particles of polymer blend are obtained, which are subsequently separated off from the water and optionally dried. Thereafter, they are foamed to expanded particles of polymer blend as described below.

A preferred process for making expandable blowing agent-containing polymer blend particles comprises the following steps:

i) melting of TPU and styrene polymer optionally with at least one filler, auxiliary and / or additive, in a preferred embodiment also at least one further thermoplastic polymer and extrusion to a granulate having an average diameter of 0.2 mm to 1 cm, ii ) Impregnating the granules with a volatile blowing agent at temperatures in the range of 100 ⁰ C to 200 ⁰ C, in aqueous suspension under pressure, preferably at a pressure between 5 bar and 100 bar, wherein the blowing agent with 0.1 wt .-% to 40 wt .-%, based on the total weight of the granules is used iii) cooling the suspension to 20 ⁰ C to 95 ⁰ C, iv) then relaxing.

Upon cooling, the blowing agent is trapped in the polymer and the product does not foam. If the vessel is relaxed directly at high temperatures in step ii), the blowing agent escapes and the polymer that is soft at these temperatures expands to form expanded particles. Another preferred process for the preparation of expandable, blowing agent-containing particles of polymer blend comprises the following steps:

i) melting TPU and styrene polymer together with 0.1 wt .-% to 40 wt .-%, based on the total weight of the granules, of a volatile

Propellant and optionally with fillers, auxiliaries and / or additives on an extruder, ii) pressing the melt and underwater granulation of the melt strand at

Press from 2 bar to 20 bar and temperatures between 5 ⁰ C and 95 ⁰ C.

In this process, granulation under water against overpressure prevents the blowing agent from escaping and the polymer from foaming.

Particularly preferred and subject of the present invention is thus also a process for the preparation of expandable, blowing agent-containing polymer blend, wherein a TPU and a styrene polymer, optionally together with at least one filler, auxiliary and / or additive, in a preferred embodiment with additionally at least one thermoplastic polymer, extruded to a granulate having a mean diameter of 0.2 mm to 1 cm, the granules with 0.1 wt .-% to 40 wt.%, Based on the total weight of the granules, a preferred volatile blowing agent in aqueous suspension under pressure, preferably at a pressure between 5 bar and 100 bar, impregnated at temperatures in the range of 100 ⁰ C to 200 ⁰ C, the suspension containing the blowing agent-containing polymer blends to 20 ⁰ C to 95 ° C and then cooling relaxes the propellant-containing polymer blends.

Also particularly preferred and subject of the present invention is also a process for the preparation of expandable, preferably particulate, blowing agent-containing polymer blend, wherein a TPU and a styrene polymer, together with 0.1 wt .-% to 40 wt .-%, based on the total weight of the granules, a preferred volatile blowing agent and optionally with fillers, auxiliaries and additives, in a preferred embodiment further with at least one thermoplastic polymer, melts on an extruder and the melt under water at pressures of 2 bar to 20 bar and Granulated temperatures between 5 ⁰ C and 95 ⁰ C.

If one obtains expandable particles, they can be foamed (foamed) in a manner known per se to give a foam, the expanded particles according to the invention being produced from polymer blend. The foaming is generally carried out by heating the expandable particles in conventional Verschäumungsvor- directions, eg with hot air or superheated steam in a so-called. Druckvor- foamer, as is customary for processing of expandable polystyrene (EPS). Preferably, the particles are foamed at a temperature at which they soften (Softening range), more preferably at temperatures between 100 ⁰ C to 140 ⁰ C.

The present invention also relates to processes for producing foams based on polymer blend to give the expandable according to the invention, preferably particulate, blowing agent-containing polymer blend at a temperature between 100 ⁰ C and 140 ⁰ C foamed. The present invention further provides foams based on polymer blend which are obtainable in this way.

Foaming with steam, so depending on the type and amount of polymer blend and blowing agent, and the desired density of the foam to be produced, the pressure of the water vapor is usually 0.5 bar to 4 bar, preferably 1, 0 bar to 3.5 bar (absolutely). Higher pressures result in lower densities of the foamed polymer blend, i. with the water vapor pressure you can set the desired density. The duration of the foaming is usually 1 sec to 300 sec, preferably 1 sec to 30 sec. After the foaming is relaxed and cooled. Preferably, the expansion factor during foaming is 2 to 50. The expansion factor describes the ratio of the volume of the foamed product to the volume of the unfoamed product.

In one embodiment of the suspension process for producing the expanded particles of polymer blend, the heated suspension, consisting of the polymer blend and blowing agent, and optionally fillers, auxiliaries and / or additives, is not cooled, but suddenly released hot without cooling , During expansion, the blowing agent previously diffused or mixed into the particles of polymer blend expands "explosively" and foams up the softened particles, resulting in expanded particles of polymer blend.

Usually, the suspension is depressurized through a nozzle, valve or other suitable device. The suspension can be immediately cooled to atmospheric pressure, about 1 bar, for example 1013 mbar. Preferably, however, is relaxed in an intermediate container whose pressure is sufficient to foam the particles of polymer blend, but the pressure may also be above atmospheric pressure. In a preferred embodiment, the pressure is released to a pressure of, for example, 0.5 bar to 5 bar, in particular 1 bar to 3 bar (absolute). In a further preferred embodiment, the impregnation pressure is kept constant during the expansion in the impregnation container by repressing the propellant. In a further preferred embodiment, the suspension is cooled after relaxing, the expanded particles of polymer blend separated from the suspension, if necessary before or after adhering suspension auxiliary removed and finally washed and dried the particles. In one embodiment of the extrusion process for producing the expanded polymer blend particles, the blowing agent-containing melt of the polymer blend is squeezed and granulated without underwater granulation, water ring granulation, or other precautions that prevent foaming. For example, it is squeezed directly into the atmosphere. In the process, the extruded melt strand foams up and, by granulating the foamed strand, expanded particles of polymer blend are obtained.

A preferred process for producing expanded foam particles from polymer blend comprises the steps

i) melting of polymer blend optionally with fillers, auxiliaries and / or additives, and extrusion to minigranules having a mean diameter of 0.2 mm to 1 cm, ii) impregnating the minigranules with 0.1% by weight to 40 wt .-%, based on the total weight of the granules, of a volatile blowing agent in aqueous suspension under pressure, preferably at a pressure between 5 bar and 100 bar at temperatures in the range of 100 ⁰ C to 200 ⁰ C and iii) subsequent expansion.

Another preferred method for producing expanded particles

Polymer blend includes the steps:

i) melting of TPU and styrene polymer together with 0.1 wt .-% to 40 wt .-%, based on the total weight of the granules, of a volatile

Propellant and optionally with fillers, auxiliaries, and / or additives, in a preferred embodiment with at least one further thermoplastic polymer, on an extruder, ii) pressing the melt and granulating the melt strand without Vorricht- tions that prevent foaming.

Particularly preferred is a process for the preparation of expanded polymer blend, wherein a TPU and a styrene polymer, optionally together with fillers, auxiliaries, and / or additives, in a preferred embodiment with at least one further thermoplastic polymer to a granule extruded with an average diameter of 0.2 mm to 1 cm, the granules with 0.1 wt .-% to 40 wt .-%, based on the total weight of the granules, a preferred volatile blowing agent, more preferably in aqueous suspension under pressure , Preferably at a pressure between 5 bar and 100 bar at temperatures in the range of 100 ⁰ C to 200 ⁰ C impregnated and then relaxed. A particularly preferred process of the present invention is the preparation of expanded polymer blend which comprises a TPU and a styrenic polymer together with from 0.1% to 40% by weight, based on the total weight of the granules, of a preferred volatile blowing agent optionally with at least one filler, auxiliary and / or additive, in a preferred embodiment with at least one further thermoplastic polymer, melts on an extruder and the melt granules without devices that prevent foaming.

The present invention further provides expanded polymer blends obtainable by such processes.

The particles of polymer blends are provided in preferred embodiments before and / or after foaming with a coating agent. Preferred coating agents are e.g. Talc, metal compounds such as tricalcium phosphate, calcium carbonate, silicic acids, in particular fumed silicas such as Aerosil® from Degussa, salts of long-chain carboxylic acids, for example stearic acid salts such as calcium stearate, esters of long-chain carboxylic acids, e.g. Glycerinester as Glycerinstea- rates, and silicone oils. Long chain carboxylic acids are preferably those having 10 to 22 carbon atoms. The coating compositions are used alone or as a mixture. The coating composition is preferably applied to the polymer blend particles by mixing, spraying, tumbling or other conventional methods. The coating compositions are preferably used in amounts of 0.01 part by weight to 20 parts by weight, more preferably 0.05 part by weight to 10 parts by weight, particularly preferably 0.1 part by weight to 6 weight. Parts, based on 100 parts by weight of the polymer blend used.

In each case, expanded particles of polymer blend are obtained. They preferably have densities of from 5 g / l to 600 g / l, and more preferably from 10 g / l to 300 g / l.

The expanded particles are generally at least approximately spherical and usually have a diameter of 0.1 mm to 20 mm, preferably 0.2 mm to 15 mm and particularly preferably 0.5 mm to 12 mm. For expanded, non-spherical, e.g. elongated or cylindrical particles, by diameter is meant the longest dimension.

The expanded particles preferably have cells of a mean cell size in the range of 10 .mu.m to 500 .mu.m. The present invention furthermore relates to processes for the production of foam on the basis of polymer blend, wherein the expanded polymer blend is welded by means of steam to form a shaped body. The temperature in the welding of the expanded particles of polymer blend is preferably between 100 ⁰ C and 140 ⁰ C.

In some embodiments, foam is made from the expanded polymer blend particles, for example, by heat sealing them together in a closed mold. In one embodiment, the particles are filled into a mold and, upon closure of the mold, introduce steam or hot air, thereby further expanding the particles and welding them together to the foam, preferably at a density in the range of 8 g / l to 600 g / l. In some embodiments, the foams are semi-finished products, such as plates, profiles or sheets, or finished moldings of simple or complicated geometry. Accordingly, the term includes foam particles of polymer blend, foam semi-finished and foam moldings with a.

The invention furthermore also relates to the use of the expanded polymer blend polymer particles for the production of polymer blend foams, as well as polymer blend foams obtainable from the expanded polymer blend particles.

An advantage of the foams according to the invention is that they can be easily recycled thermoplastically. For this purpose, the foamed polymer blends are extruded using an extruder with a degasser, the extrusion in a preferred embodiment preceded by mechanical comminution. Thereafter, they can be re-processed into foams in the manner described above.

The invention will be explained in more detail by the following example:

example 1

TPUs of the following composition were used to prepare the polymer blend: Table 1

10 parts by weight of polystyrene 158K (BASF SE) and 90 parts by weight of the TPU indicated in Table 1 were melted together in a twin-screw extruder and extruded into granules with an average diameter of 1.5 mm. In an autoclave, 100 parts by weight of granules, 250 parts by weight of water, 5 parts by weight of tricalcium phosphate, 0.1 parts by weight of dodecylbenzenesulfonate and 16 parts of n-butane were added with stirring and heated to the temperature shown in Table 2. Thereafter, the contents of the pressure vessel was discharged through a bottom valve and relaxed. The foam particles were removed by washing with nitric acid and water from the adhering residues aids and dried at 5O ⁰ C with air.

The impregnation conditions and the bulk densities of the expanded particles are shown in Table 2.

Table 2

TPU It. Table 1 n-Butane [parts by weight] Temperature [° C] Bulk density [g / L]

A 16 120 180

B 16 125 250

The foam particles prepared according to Example 1 were filled under pressure and compression in a preheated mold. This was mutually heated with steam.

Subsequently, the pressure in the mold was reduced, this cooled with water or air, opened and removed the molding.

Claims

claims

1. Expandable blowing agent-containing thermoplastic polymer blend comprising thermoplastic polyurethane and styrene polymer.

2. Polymer blend according to claim 1, characterized in that the polymer blend contains at least one further thermoplastic polymer.

3. Polymer blend according to claim 2, characterized in that the further thermoplastic polymer is selected from the group consisting of polyamide (PA),

Polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), cellulose and polyoxymethylene (POM).

4. Polymer blend according to claim 2 or 3, characterized in that add the weight proportions of thermoplastic polyurethane, styrene polymer and further thermoplastic polymer to 100 and the sum of the weight fractions of thermoplastic polyurethane and styrene polymer is between 50 and 99.

5. Polymer blend according to one of claims 1 to 4, characterized in that the weight fractions of thermoplastic polyurethane are between 5 and 95 and the weight fractions of styrene polymer are between 5 and 95 and the weight percentages of thermoplastic polyurethane and styrene polymer to 100 Add parts.

6. Polymer blend according to one of claims 1 to 5, characterized in that the thermoplastic polyurethane has a Shore hardness between A 44 and A 84.

7. Polymer blend according to one of claims 1 to 6, characterized in that the thermoplastic polyurethane is based on a polyester alcohol and / or polyether having a molecular weight between 0.6 kg / mol and 2.5 kg / mol.

8. Polymer blend according to claim 7, characterized in that the polyether alcohol is prepared from polytetrahydrofuran.

9. Polymer blend according to one of claims 1 to 8, characterized in that the styrene polymer is a styrene-acrylonitrile copolymer (SAN).

10. Polymer blend according to one of claims 1 to 8, characterized in that the styrene polymer is an acrylonitrile-butadiene-styrene copolymers (ABS).

1 1. A polymer blend according to any one of claims 1 to 10, characterized in that the propellant-containing thermoplastic polymer blend is in the form of particles having an average diameter between 0.2 mm and 1 cm.

12. Polymer blend according to one of claims 1 to 7, characterized in that the polymer blend contains between 5 wt .-% and 80 wt .-% organic and / or inorganic fillers, based on the total weight of the polymer blend, which corresponds to 100% by weight.

13. A process for the preparation of an expandable, blowing agent-containing thermoplastic polymer blend, characterized in that comprising a thermoplastic polyurethane and a styrene polymer, optionally together with at least one filler, auxiliaries, and / or additive and / or another thermoplastic polymer, to extruded granules having an average diameter of 0.2 mm to 1 cm, the granules with 0.1 wt .-% to 40% by weight, based on the total weight of the granules, which corresponds to 100 wt .-%, with a Propellant in aqueous suspension under pressure at temperatures in the range of 100 ⁰ C to 200 ⁰ C impregnated, the suspension containing the blowing agent-containing thermoplastic polymer blend to 20 ° C to 95 ° C and then cooled.

14. A process for the preparation of an expandable, blowing agent-containing thermoplastic polymer blend, characterized in that comprising a thermoplastic polyurethane and a styrene polymer, optionally together with at least one filler, auxiliaries, and / or additive, and optionally a further thermoplastic Polymer, together with 0.1 wt .-% to 40 wt .-%, based on the total weight of the granules, which corresponds to 100 wt .-%, of a blowing agent on an extruder melts and the melt under water at

Printing from 2 bar to 20 bar and granulated between 5 ° C and 95 ° C.

15. A process for producing foam based on a thermoplastic polymer blend, characterized in that comprising an expandable, blowing agent-containing, thermoplastic polymer blend according to any one of claims 1 to 12 at a temperature between 100 ⁰ C and 140 ⁰ C. foamed.

16. A thermoplastic polymer blend-based foam obtainable by a process according to any one of claims 13 and 14.

17. Process for producing an expanded, thermoplastic polymer

Blends, characterized in that one extrudes a thermoplastic polyurethane and a styrene polymer, to a granulate having an average diameter of 0.2 mm to 1 cm, the granules with 0.1 wt .-% to 40 wt .-% of a blowing agent Pressure at temperatures in the range of 100 ⁰ C to

200 ⁰ C impregnated and then relaxed, wherein the wt .-% of the blowing agent based on the total weight of the granules, which corresponds to 100 wt .-%.

18. A process for the preparation of an expanded, propellant-containing thermoplastic polymer blend, characterized in that comprising a thermoplastic polyurethane and a styrene polymer, with 0.1 wt .-% to 40 wt .-%, based on the total weight of the granules, the 100th % By weight, melts a blowing agent on an extruder and squeezes and granulates the melt.

19. A process for producing an expanded, blowing agent-containing thermoplastic polymer blend, characterized in that a thermoplastic polyurethane and a styrene polymer, together with 0.1 wt .-% to 40 wt .-%, of a blowing agent are melted on an extruder, wherein the

Wt .-% based on the total weight of the expanded polymer blend corresponding to 100 wt .-%, and the melt without devices that prevents foaming, pressed and expanded.

20. Expanded polymer blend obtainable by a process according to one of claims 17 to 19.

21. Expanded polymer blend according to any one of claims 17 to 19, characterized in that the thermoplastic polymer blend contains between 5 wt .-% and 80 wt .-% of organic and / or inorganic fillers, based on the total weight of the thermoplastic polymer Blends equal to 100% by weight.

22. A process for the production of foam based on thermoplastic polymer blend, characterized in that one fuses an expanded thermoplastic polymer blend according to claim 20 by means of steam at a temperature between 100 ° C and 140 ⁰ C to form a shaped body.