Thermoplastic polyester polyurethane with shape memory and / or thermoresponsive properties, process for its production and molded part produced therefrom

Abstract

Thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, comprising: - hard segments containing polyurethane units obtained by polyaddition of the isocyanate groups of at least one diisocyanate with the hydroxyl groups of at least one first diol serving as a chain extender to form urethane groups; and - crystallizable soft segments containing polyester units, wherein the polyester units are linked to the hard segments by polyaddition of corresponding polyester diols and / or polyols with the isocyanate groups of the at least one diisocyanate to form urethane groups; and wherein the polyester diols and / or polyols are obtained by polycondensation of the hydroxyl groups of at least one second diol with at least one dicarboxylic acid or with its derivatives to form ester groups.wherein the polyester diols and / or polyols of the polyester units of the soft segments have an average molar mass between 1500 g / mol and 7000 g / mol, wherein the switching temperature of the thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, corresponding to the melting temperature of the soft segments, is at least 50°C, and wherein the shape fixing temperature of the thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, corresponding to the crystallization temperature of the soft segments, is at least 25°C.

Description

The invention relates to a thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, a polymer molded part containing such a material, and a method for its production. Shape-memory polymers are polymers that typically consist of at least two polymer components or a single polymer component with various segments. These segments include, on the one hand, so-called hard segments, which also function as lattice points. On the other hand, there are so-called soft segments, which connect the lattice points and are also referred to as switching segments. The soft or switching segments are elastic at elevated temperatures (in which case they exist in an amorphous form), while at lower temperatures they are rigid (in which case they exist in a semi-crystalline or vitrified form). Such polymers can be programmed with regard to their shape by heating them to a temperature that corresponds at least to the so-called switching temperature, at which the phase transition (glass transition or melting transition) of the soft or switching segments occurs.At such a temperature, the polymer is deformed, after which it is cooled to its so-called shape-fixing temperature. This temperature corresponds to the crystallization temperature or glass transition temperature of the soft or switching segments and can be in the range of the switching temperature, but is usually lower. The soft or switching segments then exist again in a semi-crystalline or vitrified form, so that the shape is retained.This shaping, however, is only temporary insofar as when such a mechanically deformed shape-memory polymer, "programmed" in this way, is heated to a specific temperature, namely its switching temperature, the soft segments (switching segments) revert to their amorphous form. This prevents them from counteracting the restoring force induced by the hard component (lattice points), and the shape-memory polymer returns to its original shape; the mechanical deformation is thus "reversed." Furthermore, some shape-memory polymers can also be programmed by cold forming. This involves deforming the polymers at a temperature below their switching temperature, e.g., at ambient temperature, and then, if the shape-fixing temperature is lower, cooling them to their shape-fixing temperature.In this case, too, only temporary deformation takes place, insofar as a re-deformation occurs upon renewed heating, at least to the switching temperature, in order to transfer the soft segments (switching segments) into the amorphous phase and thereby relax the mechanical stresses induced during cold deformation. In addition to shape memory, thermoresponsive polymers can also exhibit temperature memory. This means that when the shape memory effect is triggered, the material returns to its original shape at approximately the temperature at which the mechanical deformation was initially introduced. Polymers with semi-crystalline network structures, such as thermoplastic polyurethane elastomers, exhibit this type of material behavior (N. Fritzsche, T. Pretsch in Macromolecules 47, 2014, 5952-5959; N. Mirtschin, T. Pretsch in RSC Advances 5, 2015, 46307-46315). One application area for such polymers with shape memory and / or thermoresponsive properties is in various medical applications, including bandages, compresses, insoles, and the like, but also in everyday objects such as dishes, toys, pacifiers, textiles, mattresses, hoses, spindles, and the like. Another interesting application lies in information carriers, for example, for the tamper-proof marking of goods to verify their authenticity. This is achieved, for instance, by exploiting the fact that a code applied to the goods—for example, a machine-readable and / or otherwise optically uniquely identifiable code—only becomes visible or readable when the information carrier made from such polymers is heated to its switching temperature, after having been (temporarily) deformed using the programming described above.After processing, such polymer molded parts, like information carriers or any other molded parts such as those mentioned above, possess shape and / or temperature memory. In addition to thermoresponsiveness, thermochromic properties can also be provided, provided the polymer molded part has been printed or treated with appropriate thermochromic dyes or pigments. In the case of information carriers, authenticity can then be further verified by a color change at the corresponding color-changing temperature; in the case of any other molded parts, this creates a special effect. Furthermore, such polymer molded parts can, for example,also with magnetoresponsive or electroactive additives, especially in fine particulate form, which can trigger a shape change by inductive heating after the polymer with shape memory properties and / or thermoresponsive properties has been mixed with such additives and subsequently programmed. A disadvantage of currently known polyurethane-based thermoplastic shape memory polymers is that their switching temperatures are very limited, being significantly above approximately 20°C and, in particular, above the human body temperature of approximately 37°C. Furthermore, their shape-fixing temperature is considerably lower. This limits the potential applications of shape memory polymers, severely restricting their use and, especially, their switching capabilities at higher ambient or process temperatures. For example, polycaprolactone-based thermoplastic polyurethanes with a melt transition temperature of the soft segments of up to approximately 55°C are known (B. Bogdanov, V. Toncheva, E. Schacht, L. Finelli, B. Sarti, M. Scandola: “Physical properties of poly(ester-urethane) prepared from different molar mass polycaprolactone-diols”, Polymer 40, 1999, 3171-3182; J. Kloss, M. Munaro, GP De Souza, JV Gulmine, SH Wang, S. Zawadzki, L. Akcelrud: “Poly(ester urethane)s with polycaprolactone soft segments: a morphological study”, J. Polym. Sci. Part A: Polym. Chem. 40, 2002, 4117-4130), which are one of the few, but much-studied, representatives of thermoplastic polyurethanes with Represent shape memory properties with a switching temperature higher than room temperature.If the polycaprolactone diol has an unusually high molar mass for the synthesis of thermoplastic polyurethanes, which can lead to coupling problems and an unclean reaction, and a low hard segment content, the melting point peak in the DSC thermogram (differential scanning calorimetry) can be brought close to that of the starting diol at 62°C (MW = 7000 g / mol and HSC = 18.7% in F. Li, L. Qi, J. Yang, M. Xu, X. Luo and D. Ma, J. Appl. Polym. Sci. 75, 2000, 68). For the pure polycaprolactone with a molecular weight of 2000 g / mol, signals with respective peaks at 56°C and 63°C appear in the DSC thermogram during the melting point upon heating. In contrast, during the subsequent cooling, the crystallization of polycaprolactone takes place below room temperature, namely at the peak at 17°C (J. Kloss, M. Munaro, GP De Souza, JV Gulmine, SH Wang, S. Zawadzki, L. Akcelrud, J. Polym. Sci.Part A: Polym. Chem. 40, 2002, 4117-4130). Furthermore, shape-memory polymers are known in the form of polyether polyurethanes based on polytetramethylene glycol (PTMG), which exhibit a melting peak in the DSC thermogram at approximately 73°C and a crystallization peak at approximately 28°C (JD Merline, CP Nair, C. Gouri, GG Bandyopadhyay, KN Ninan, J. Appl. Polym. Sci. 107, 2008, 4082-4092). Other shape-memory polymers with similarly high switching and shape-fixing temperatures are only found in the class of amorphous materials. However, in these materials, any increase in the switching temperature is always accompanied by a higher degree of cross-linking. This leads to poorer thermal processability, even to the point of thermosetting material behavior. Finally, polymer blends with shape memory properties are known, containing various blend partners. For example, the article by A. Shirole et al., “Tailoring the shape memory properties of segmentes poly(esterurethanes) via blending”, ACS Applied Materials Interfaces 10 (2008), 1944-8252, describes a polymer blend with shape memory properties that contains, on the one hand, a shape memory polymer, namely a commercially available polyurethane (PBA-PU) with poly(1,4-butylene adipate) (PBA) as crystallizable (soft) segments with an average molar mass of 12000 g / mol, and, on the other hand, hard segments obtained by reacting 4,4'-methylenediphenyl diisocyanate with 1,4-butanediol. On the other hand, the known polymer blend with the aforementioned commercially available shape memory polymer contains a blend partner in the form of another polymer without shape memory properties, namely either poly-(1,4-butylene adipate) (PBA) or poly(ε-caprolactone) (PCL). The invention is based on the objective of proposing a relatively simple and cost-effective thermoplastic polyester polyurethane with shape memory properties and / or thermoresponsive properties, which, while ensuring high shape recovery, exhibits a higher switching temperature and, in particular, a higher shape fixing temperature compared to the prior art, in order to open up a wider range of applications. It is further directed to a method for producing such a thermoplastic polyester polyurethane with shape memory properties and / or thermoresponsive properties, as well as to a molded part containing such a material. The first part of this problem is solved according to the invention with a thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, comprising: - hard segments containing polyurethane units obtained by polyaddition of the isocyanate groups of at least one diisocyanate with the hydroxyl groups of at least one first diol serving as a chain extender to form urethane groups, and - crystallizable soft segments containing polyester units, wherein the polyester units are linked to the hard segments by polyaddition of corresponding polyester diols and / or polyols with the isocyanate groups of at least one diisocyanate to form urethane groups.and wherein the polyester diols and / or polyols are obtained by polycondensation of the hydroxy groups of at least a second diol with at least one dicarboxylic acid or with its derivatives to form ester groups, wherein the polyester diols and / or polyols of the polyester units of the soft segments have an average molar mass between 1500 g / mol and 7000 g / mol, wherein the switching temperature of the thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, corresponding to the melting temperature of the soft segments, is at least 50°C, and wherein the shape fixing temperature of the thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, corresponding to the crystallization temperature of the soft segments, is at least 25°C. In terms of process engineering, the invention provides a process for producing such a thermoplastic polyester polyurethane to solve this problem, comprising the following steps: (a) providing at least one second diol and at least one dicarboxylic acid or its derivatives; (b) reacting the at least one second diol with the at least one dicarboxylic acid or its derivatives according to step (a) to give polyester diols and / or polyols with an average molar mass between 1500 g / mol and 7000 g / mol;and (c) reacting at least one diisocyanate with at least one first diol serving as a chain extender in the presence of the polyester diols and / or polyols according to step (b) to form the polyurethane units of the hard segments by polyaddition of the isocyanate groups of the at least one diisocyanate with the hydroxy groups of the at least one second diol, and to connect the polyester units serving as soft segments to the hard segments via urethane bonds by polyaddition of the hydroxy groups of the polyester diols and / or polyols according to step (b) with the isocyanate groups of the at least one diisocyanate, thereby obtaining the thermoplastic polyester polyurethane with a switching temperature of at least 50°C and a mold fixing temperature of at least 25°C. Finally, to solve this problem, the invention provides a polymer molded part which contains at least one thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties of the aforementioned type or a polymer blend with at least one such polyester polyurethane or is entirely formed therefrom, wherein the switching temperature is at least 50°C and the mold fixing temperature is at least 25°C. The semicrystalline thermoplastic polyester polyurethane according to the invention therefore comprises, on the one hand, hard segments containing polyurethane units obtained by polyaddition of the isocyanate groups (-N=C=O groups) of at least one diisocyanate with the hydroxyl groups (-OH groups) of at least one first diol serving as a chain extender, forming urethane groups (-NH-CO-O-). On the other hand, the semicrystalline thermoplastic polyester polyurethane according to the invention comprises soft segments containing polyester units, wherein the polyester units are linked to the hard segments by polyaddition of corresponding polyester diols and / or polyols with the isocyanate groups of at least one diisocyanate, forming urethane groups.The polyester diols and / or polyols are obtained by reacting the hydroxy groups of at least one second diol with at least one dicarboxylic acid or with its derivatives, such as the corresponding diacid halides, diesters, cyclic anhydrides or the like, to form ester groups (-CO-O-).According to the invention, the polyester diols and / or polyols of the polyester units of the soft segments have an average molar mass between about 1500 g / mol and about 7000 g / mol, so that the switching temperature of the thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, corresponding to the melting temperature of the soft segments, is at least about 50°C, while the shape fixation temperature of the thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, corresponding to the crystallization temperature of the soft segments, is at least about 25°C, but the polyester polyurethane nevertheless remains thermoplastic. The thermoplastic polyester polyurethanes according to the invention, possessing shape memory and / or thermoresponsive properties, can be produced using methods known as such, such as the one-shot or prepolymer process. The molar ratio of isocyanate-reactive groups, i.e., the sum of the hydroxyl groups of the polyester diols and / or polyols on the one hand and of the first diols serving as chain extenders on the other, to the isocyanate groups of the at least one diisocyanate, should preferably be adjusted in step (c) of the production process according to the invention to approximately 0.8 : 1 to approximately 1.2 : 1, in particular to approximately 0.9 : 1 to approximately 1.1 : 1, for example in the range of approximately 1:1. The processing of thermoplastic polyester polyurethanes with shape memory and / or thermoresponsive properties, which are usually available as granules or in powder form, into the desired polymer molded parts can be carried out, for example, using known thermoplastic processing methods such as injection molding, extrusion, hot pressing, sintering or the like. In addition to the starting materials described above, catalysts, chain terminators, and auxiliary and / or additives known as such can also be used to produce thermoplastic polyester polyurethane with shape memory and / or thermoresponsive properties. For example, catalysts may be used, if necessary, during the polyaddition according to step (c) of the process according to the invention, which accelerate the reaction between the isocyanate groups of the diisocyanates and the hydroxy groups of the first diols or the polyester diols and / or polyols produced according to step (b). Examples of such potentially suitable catalysts include tertiary amines, such as triethylamine, triisopropylamine, tri-n-propylamine, N,N'-dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol, diazabicyclo-(2,2,2)-octane, and in particular organic metal compounds, such as zirconium complex catalysts, titanium esters, such as titanium tetraisopropylate, titanium tetrabutylate, iron compounds, such as iron(III) acetylacetonate, tin compounds, such as tin diacetate, tin dioctoate, tin dilaurate, or the tin dialkyl salts of aliphatic carboxylic acids, such as...Dibutyltin diacetate and dibutyltin dilaurate. In the polyaddition according to step (c) of the process according to the invention, compounds which have only one group reactive towards isocyanate groups, such as monoalcohols, e.g., ethanol, 1-propanol, 2-propanol, 1-butanol, 1-hexanol, 1-octanol, stearyl alcohol and the like, can be used as chain terminators. Such chain terminators can, for example, additionally be used to selectively adjust the molecular weight, melt viscosity and thus also the flow behavior of the thermoplastic polyester polyurethanes with shape memory and / or thermoresponsive properties. Further auxiliary and / or additive substances known from the prior art, such as surfactants, flame retardants, nucleation agents, lubricants and demolding agents, dyes, pigments and fillers, inhibitors, stabilizers against hydrolysis, light, heat, oxidation or discoloration, protective agents against microbial degradation, as well as reinforcing agents and plasticizers, can be used. The thermoplastic polyester polyurethanes according to the invention with shape memory and / or thermoresponsive properties can also contain, for example, an oil component (e.g., silicone oil). Examples of further auxiliary and / or additive substances include fillers, which may, for example, have a graphene structure, such as that found in graphite, carbon nanotubes (CNTs), graphene flakes, or expanded graphite.Other particles, preferably with a nanoscale dimension, can also be used as auxiliary and / or additive materials or fillers, such as magnetic (nano)particles, including ferromagnetic particles, in particular NiZn particles, iron oxide particles, and magnetite particles, etc. So-called nanoclays can also be used as auxiliary and / or additive materials or fillers. Such nanoclays can be based, for example, on silicon nitride, silicon carbide, silicon oxide, zirconium oxide, and / or aluminum oxide. Other possible fillers include oligomeric silsesquioxanes, graphite particles, graphene, carbon nanotubes, synthetic fibers, e.g., aramid fibers, carbon fibers, glass fibers, and the like, as well as metal and metal oxide particles. Combinations of such filler materials can, of course, also be used.The fillers are suitable for adjusting the mechanical, electrical, magnetic and / or optical properties of thermoplastic polyester polyurethane with shape memory and / or thermoresponsive properties and adapting them to the respective application. The thermoplastic polyester polyurethanes according to the invention, with shape memory and / or thermoresponsive properties, are able, particularly due to their high switching and shape-fixing temperatures, to significantly expand the application areas of segmented shape memory polymers based on polyurethane, i.e., those with both hard and soft segments, and to open up new fields of application for such shape memory polymers. For example, one advantage of the thermoplastic polyester polyurethanes according to the invention is that their biocompatibility and biodegradability can be specifically controlled, thereby enabling bio-based thermoplastic polyester polyurethanes to enter into new, particularly technical, applications. Furthermore, the polyester polyurethanes offer the possibility of fine-tuning one-way and two-way shape memory effects.Fundamental advantages of the thermoplastic polyester polyurethanes according to the invention also lie in their thermoplastic properties, even at high switching and shape-fixing temperatures. In particular, they can be readily processed using standard thermoplastic manufacturing processes (extrusion, injection molding, hot pressing, etc.) and are also recyclable or biodegradable. With regard to their morphology, the crystallizable soft segments, with their melt transitions, offer a defined thermal phase transition that allows for the targeted and rapid initiation of shape memory effects. Furthermore, melt and crystallization transitions are a prerequisite for bidirectional actuation, and these melt transitions are relatively inert to external influences.As explained in more detail below, the choice of primarily linear polyester-based soft segments results not only from their high tendency to crystallize, but also from their application-related advantages, e.g., compared to polyether polyols. These include better mechanical properties, such as higher tensile strength, good heat resistance, etc., higher tear and abrasion resistance, greater resistance to solvents, oils, greases, and fuels, lower costs, the possibility of producing them from bio-based, especially biocompatible and / or biodegradable, raw materials, and the good synthetic accessibility of the diols used. The polymer molded parts according to the invention, whose shape recovery after stretching with 100% elongation under heating is at least to the switching temperature of the at least one thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties is generally at least about 80%, in particular at least about 85%, preferably at least about 88%, for example at least about 90%, can be used in addition to usual areas of application wherever higher switching and / or shape fixing temperatures are necessary due to the ambient or process conditions.Depending on the type of programmed shape memory effect (1-way shape memory effect, 2-way shape memory effect, multiple shape memory effect), polymer molded parts made from the thermoplastic polyester polyurethanes according to the invention or from blends, compounds and composites containing such materials can be used, for example, as follows: - Switches and control elements in technical devices and processes, - Actuators, for example in safety-relevant applications, electrical circuits, etc., - Components in micromechanical systems, drive systems, locking systems, brackets, etc., - Components in heat engines for converting thermal into kinetic energy or for the temporary storage of heat energy, - for active surfaces. Depending on the mean molar mass of the crystallizable soft segments of the thermoplastic polyester polyurethane according to the invention with shape memory and / or thermoresponsive properties, and depending on the second diols and in particular the dicarboxylic acids used for their production (see below), it is advantageous that: - the switching temperature of the thermoplastic polyester polyurethane can be at least about 60°C, in particular at least about 70°C, preferably at least about 80°C, for example at least about 90°C; and / or - the shape fixing temperature of the thermoplastic polyester polyurethane can be at least about 30°C, in particular at least about 35°C, preferably about 40°C. For this purpose, the polyester diols and / or polyols of the soft segments can advantageously have an average molar mass of at least about 2500 g / mol or of more than about 2500 g / mol, in particular of at least about 2750 g / mol, preferably of at least about 3000 g / mol, for example of at least about 3200 g / mol; and / or of at most about 9000 g / mol, in particular of at most about 8000 g / mol, preferably of at most about 7000 g / mol, for example of at most about 6500 g / mol. An advantageous embodiment of the manufacturing process according to the invention may therefore provide that, in step (b), the at least one second diol is reacted with the at least one dicarboxylic acid or its derivatives to form polyester diols and / or polyols with an average molar mass of at least about 2500 g / mol or of more than about 2500 g / mol, in particular of at least about 2750 g / mol, preferably of at least about 3000 g / mol, for example of at least about 3200 g / mol; and / or of at most about 6500 g / mol. In an advantageous embodiment, with regard to the structure of the crystallizable polyester-based soft segments with high melting transition temperatures of at least about 60°C or, in particular, at least about 70°C, it can preferably be provided that the at least one dicarboxylic acid or its derivatives, from which the polyester diols and / or polyols of the polyester units of the soft segments have been obtained, is from the group of aliphatic dicarboxylic acids or their derivatives, in particular with 4 to 12 carbon atoms, preferably from the group of butanedioic acid (succinic acid), hexanedioic acid (adipic acid), octanedioic acid (suberic acid, etc.).Coric acid), nonanedioic acid (azelaic acid) and decanedioic acid (sebacic acid) or their derivatives including mixtures thereof; or- of the aromatic dicarboxylic acids or their derivatives, in particular from the group terephthalic acid, isophthalic acid, ortho-phthalic acid and 2,5-furandicarboxylic acid or their derivatives including mixtures thereof. The at least one second diol from which the polyester diols and / or polyols of the polyester units of the soft segments have been obtained may advantageously be selected from the group of alkanediols, in particular from the group consisting of ethanediol (ethylene glycol), 1,3-propanediol (propylene glycol), 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol and 1,12-dodecanediol, including mixtures thereof. The polyester diols and / or polyols used to produce the soft segments of the thermoplastic polyester polyurethanes according to the invention, which have shape memory and / or thermoresponsive properties, can be formed exclusively from one dicarboxylic acid and one second diol, such as those of the aforementioned type, or they can also be copolymers containing blocks of the aforementioned polyester units plus at least one chain segment of at least one further oligomer or polymer. The minimum number of repeating units of the polyester units is, in particular, 2. Furthermore, higher-grade and / or higher-molecular-weight alcohols or mixtures of different alcohols can also be used. Examples of typical representatives are known to those skilled in the art and are described in detail in the literature. In the case of the terephthalic acid-based polyester units of the soft segments, for example,Diols with carbon chains of at least 4 or, in particular, at least 5 carbon atoms can be used, resulting in polyester diols and / or polyols with melting points in the range of approximately 80°C to approximately 150°C. Alternatively, block copolymers or ABA block oligomers of the aforementioned polyester diols and / or polyols can be used, the mechanical properties of which can be specifically tailored by reacting them with oligo- or polymers. In any case, the crystallizable polyester-based soft segments of the thermoplastic polyester polyurethane can be structured such that their crystallization behavior is largely similar to that of the "pure" polyester diols and / or polyols, so that the switching temperatures of the soft segments (peak temperature) of the polyester polyurethane deviate from those of the pure polyester diol and / or polyol by a maximum of approximately 30°C, preferably a maximum of approximately 15°C.This ensures good switching behavior and is crucial for shape memory properties. Depending on the type and amount of co-monomers or short-chain co-oligo- or -polymers used, the melting temperatures of the resulting polyester polyols can range, for example, from approximately 60°C to approximately 250°C. Examples of co-monomers used include aliphatic and cycloaliphatic as well as aromatic dicarboxylic acids and / or polyalcohols. The various methods for obtaining such copolymers include, among others, random and stepwise copolymerization and transesterification, and are well known to those skilled in the art and described in detail in the literature. Among the oligo- or polymers suitable for further chain segments of the soft segments, and which can be used to adjust the flexibility or brittleness of the soft segments, e.g., by copolymerization or linkage with the polyester diols and / or polyols, are polyether diols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, or mixtures thereof. Furthermore, polyester diols such as oligomeric polyalkylene adipates, polycaprolactones, and any type of amorphous (co-)polyester can be used. Polyether esters, polyether carbonates, polyester carbonates, or other hydroxy- and / or amino-terminated, flexible oligo- or polymers can also be employed.They can be used individually or in the form of mixtures with each other or in mixture with the second diols described above and preferably have an average molar mass of about 200 g / mol to about 3000 g / mol, in particular from about 300 g / mol to about 1000 g / mol. Furthermore, oligo- or polymers, which can be used as an additional di- or polyol component in the di- or polyol composition for a further chain segment of the soft segments during the polyaddition according to step (c) of the process according to the invention, and which can be used as additional components in the mixture with the aforementioned (co-)polyester diols and / or polyols with high phase transition temperatures in order to selectively adjust the mechanical properties of the thermoplastic polyester polyurethanes according to the invention, are known to those skilled in the art and are described in detail in the literature. These include, among others, polyether diols, such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, or mixtures thereof. Furthermore, for example, polyester diols, such as oligomeric or polymeric polyalkylene adipates, polycaprolactones, and any type of amorphous (co-)polyesters can be used.Polyether esters, polyether carbonates, polyester carbonates, or other hydroxy- or amino-terminated, flexible oligo- or polymers can also be used. They can be used individually or in mixtures with each other and preferably have an average molar mass of about 500 g / mol to about 10,000 g / mol, particularly about 600 g / mol to about 7,500 g / mol, and most preferably about 800 g / mol to about 5,000 g / mol. The highest phase transition temperature (melting or glass transition) of these compounds is advantageously at least 10°C, preferably at least 20°C, and particularly at least 30°C, below that of the high-melting polyester diol and / or polyol. According to an advantageous embodiment of the thermoplastic polyester polyurethane according to the invention, it can therefore be provided that the polyester units of the soft segments have at least one chain segment formed by at least one further oligomer or polymer, which is obtained in particular by reaction of at least one further hydroxy- and / or amino-terminated oligomer or polymer with the polyester diols and / or polyols, or by copolymerization of the at least one second diol with the at least one dicarboxylic acid or its derivatives and at least one further hydroxy- and / or amino-terminated oligomer or polymer, or by copolymerization of the at least one second diol with the at least one dicarboxylic acid or its derivatives and at least one further di- or polyalcohol and / or with at least one further di- or polycarboxylic acid.The further hydroxy- and / or amino-terminated oligomer or polymer may preferably be selected from the group of polyether polyols, such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol including mixtures thereof, polycaprolactones, polyether esters, polyether carbonates and polyester carbonates including mixtures thereof. In terms of process engineering, it may therefore be provided that: - the polyester diols and / or polyols are reacted with at least one further hydroxy- and / or amino-terminated oligomer or polymer during step (b), or - the reaction of the at least one second diol with the at least one dicarboxylic acid or its derivatives to form the polyester diols and / or polyols according to step (b) is carried out in the presence of at least one further hydroxy- and / or amino-terminated oligomer or polymer, or - the reaction of the at least one second diol with the at least one dicarboxylic acid or its derivatives to form the polyester diols and / or polyols according to step (b) is carried out in the presence of at least one further di- or polyalcohol and / or at least one further di- or polycarboxylic acid.to introduce a chain segment formed by at least one other oligomer or polymer into the polyester units of the soft segments. The at least one diisocyanate from which the polyurethane units of the hard segments have been obtained may preferably be selected from the group of aromatic, aliphatic or cycloaliphatic diisocyanates, in particular from the group of isomers or isomer mixtures of methylenediphenyl diisocyanates (MDI), 1,6-hexamethylene diisocyanate (HDI), 4,4'-diisocyanatodicyclohexylmethane (H12MDI), isomers or isomer mixtures of toluene diisocyanates (TDI), 1,5-pentadiisocyanate (PDI) including mixtures thereof. The at least one first diol serving as a chain extender, from which the polyurethane units of the hard segments have been obtained, may preferably be selected from the group of alkanediols, in particular from the group consisting of ethanediol (ethylene glycol), 1,3-propanediol (propylene glycol), 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol and 1,12-dodecanediol, including mixtures thereof. The hard segments of the thermoplastic polyester polyurethanes according to the invention with shape memory and / or thermoresponsive properties can therefore advantageously be composed of at least one aromatic, aliphatic or cycloaliphatic diisocyanate, such as isomers or isomer mixtures of methylene diphenyl diisocyanates (MDI), isophorone diisocyanate (IPDI), 1,6-hexamethylene diisocyanate (HDI), 4,4'-diisocyanatodicyclohexylmethane (H12MDI), isomers or isomer mixtures of toluene diisocyanates (TDI), 1,5-pentane diisocyanate (PDI) or mixtures thereof, and at least one first diol serving as a chain extender.The diols serving as chain extenders can be generally known dihydroxy compounds, in particular ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol and 1,12-dodecanediol including mixtures thereof. Furthermore, additional chain extenders based on diamine compounds can be used if necessary. Possible diamine compounds include, for example, isophorone diamine, ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, N-methylpropylene-1,3-diamine, N,N'-dimethylethylenediamine, and aromatic diamines such as 2,4-toluenediamine, 2,6-toluenediamine, 3,5-diethyl-2,4-toluenediamine, and 3,5-diethyl-2,6-toluenediamine, or primary mono-, di-, tri-, or tetraalkyl-substituted 4,4'-diaminodiphenylmethanes, including mixtures thereof. Amino alcohols, such as N-2-(methylamino)ethanol or 3-(methylamino)-1-propanol, and the like, can also be considered as additional chain extenders. Such additional chain extenders can be used individually in combination with the at least one first diol, as well as in any mixture with each other and with the at least one first diol.However, such diamines would not be suitable as sole chain extenders, since the resulting polyureas, unlike the polyurethane according to the invention, could not be processed thermoplastically and also exhibited insufficient shape memory properties. The thermoplastic polyester polyurethane according to the invention can be provided to be unbranched; or slightly branched, wherein the polyurethane units are obtained in particular by polyaddition of the isocyanate groups of at least one diisocyanate with the hydroxy groups of at least one first diol serving as a chain extender and at least one additional tri- or polyol with the isocyanate groups to form urethane groups, wherein the tri- or polyol is preferably selected from the group of trifunctional alkanols, such as trimethylolpropane, propane-1,2,3-triol (glycerol) and 2,2-bis(hydroxymethyl)-1,3-propanediol (pentaerythritol) including mixtures thereof. To avoid excessive branching of the polyester polyurethane and to maintain its thermoplastic properties, the numerical average functionality of the first diol serving as a chain extender and of the at least one additional tri- or polyol should be at most about 2.5, preferably at most about 2.3, and in particular at most about 2.1. With regard to the programming of the polyester polyurethane according to the invention, it may be advantageously provided that the thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties is at least partially deformed for programming at a temperature above approximately 50°C, in particular above approximately 60°C, preferably above approximately 70°C, for example above approximately 80°C, which corresponds at least to the switching temperature of the thermoplastic polyester polyurethane, after which it is cooled and relieved at least to its shape fixing temperature of at least approximately 25°C, in particular of at least approximately 30°C, preferably of at least approximately 35°C. Further features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the drawings. Figure 1A shows a graph of the heat flow determined by differential scanning calorimetry as a function of temperature of a polyester diol in the form of polybutylene succinate diol (PBS) with an average molar mass of 3500 g / mol, used as a crystallizable soft segment in a first embodiment of a thermoplastic polyester polyurethane according to the invention, wherein the upper curve was recorded during the second heating and the lower curve during the second cooling; Figure 1B shows a graph of the heat flow determined by differential scanning calorimetry as a function of temperature of the first embodiment of a thermoplastic polyester polyurethane according to the invention, which contains soft segments made from the polyester diol according to Figure 1.1A comprising polyester units obtained by polyaddition of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with 1,4-butanediol (1,4-BD); Fig. 2A a graph of the heat flow determined by differential scanning calorimetry versus the temperature of a polyester diol in the form of polydecylene terephthalate diol (PDT) with an average molar mass of 2900 g / mol, used as a crystallizable soft segment for a second embodiment of a thermoplastic polyester polyurethane according to the invention, wherein the upper curve was recorded during the second heating and the lower curve during the second cooling; Fig. 2B a graph of the heat flow determined by differential scanning calorimetry versus the temperature of the second embodiment of a thermoplastic polyester polyurethane according to the invention, which comprises soft segments made from the polyester diol according to Fig.2A, comprising polyester units obtained by polyaddition of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with 1,4-butanediol (1,4-BD); Fig. 3A, a graph of the heat flow determined by differential scanning calorimetry versus temperature of a polyester diol in the form of polydecylene adipate diol (PDA) with a mean molar mass of slightly more than 2500 g / mol, used as a crystallizable soft segment in a third embodiment of a thermoplastic polyester polyurethane according to the invention, wherein the upper curve was recorded during the second heating and the lower curve during the second cooling; Fig. 3B, a graph of the heat flow determined by differential scanning calorimetry versus temperature of the third embodiment of a thermoplastic polyester polyurethane according to the invention, comprising soft segments made from the polyester diol according to Fig.3A, comprising polyester units obtained by polyaddition of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with 1,4-butanediol (1,4-BD); Fig. 4A, a graph of the heat flow determined by differential scanning calorimetry versus the temperature of a polyester diol in the form of polydecylenesuccinate diol (PDS) with a mean molar mass of slightly more than 2750 g / mol, used as a crystallizable soft segment in a fourth embodiment of a thermoplastic polyester polyurethane according to the invention, wherein the upper curve was recorded during the second heating and the lower curve during the second cooling; and Fig. 4B, a graph of the heat flow determined by differential scanning calorimetry versus the temperature of the fourth embodiment of a thermoplastic polyester polyurethane according to the invention, which comprises soft segments made from the polyester diol according to Fig.4A contains polyester units obtained, as well as hard segments containing polyurethane units obtained by polyaddition of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with 1,4-butanediol (1,4-BD). All DSC thermograms according to Figs. 1A to 4B were recorded under comparable conditions with heating and cooling rates of 10°C / min and -10°C / min respectively, and with holding times at the reversal points of 3 min each for the measurements of the polyester diols (Fig. 1A, Fig. 2A, Fig. 3A and Fig. 4A) and of 5 min each for the measurements of the polyester polyurethanes (Fig. 1B, Fig. 2B, Fig. 3B and Fig. 4B). Examples of implementation: Example 1: Production of a first embodiment of a thermoplastic polyester polyurethane with shape memory or thermoresponsive properties: Hard segments: Polyurethane units, which are connected by polyaddi- tion of a diisocyanate in the form of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with a first diol serving as a chain extender in the form of 1,4-butanediol (1,4-BD); Soft segments: Polyester units based on a polyester diol in the form of polybutylene succinate diol (PBS) with a numerical mean molar mass of 3500 g / mol, which was obtained by polycondensation of a second diol in the form of 1,4-butanediol with a dicarboxylic acid in the form of butanedioic acid (succinic acid, SA). Polybutylene succinate diol (PBS) with an average molar mass of 3500 g / mol is produced by the polycondensation of 1,4-butanediol with butanedioic acid (succinic acid) using titanium(IV) isopropoxide (TTIP) as a catalyst. The corresponding DSC diagram is shown in Fig. 1A, which reveals that the melting point of polybutylene succinate diol (PBS) is approximately 111°C, while its crystallization temperature is approximately 76°C. The reaction of polybutylene succinate diol (PBS), produced as described above, with 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) and 1,4-butanediol (1,4-BD) in the molar ratio of PBS : 4,4'-MDI : 1,4-BD = 1 : 3.5 : 2.5 according to the prepolymer process yields thermoplastic polyester polyurethane with shape memory and thermoresponsive properties, which contains the soft segments based on polyester units with an average molar mass of 3500 g / mol. The corresponding DSC diagram can be found in Fig. 1B, which shows that the switching temperature of the thermoplastic polyester polyurethane is approximately 100°C, while its shape-fixing temperature is approximately 56°C. The shape recovery (after stretching with 114% elongation under heating at least to the switching temperature and subsequent cooling at least to the shape fixing temperature as well as unloading of a test specimen produced therefrom) is approximately 94%. Example 2: Production of a second embodiment of a thermoplastic polyester polyurethane with shape memory or thermoresponsive properties: Hard segments: Polyurethane units obtained by polyaddition of a diisocyanate in the form of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with a first diol serving as a chain extender in the form of 1,4-butanediol (1,4-BD); Soft segments: Polyester units based on a polyester diol in the form of polydecylene terephthalate diol (PDT) with a numerical mean molar mass of 2900 g / mol, which was obtained by polycondensation of a second diol in the form of 1,10-decanediol (1,10-DD) with a dicarboxylic acid derivative in the form of dimethyl terephthalate (DMT). Polydecylene terephthalate diol (PDT) with an average molar mass of 2900 g / mol is produced by the polycondensation of 1,10-decanediol with dimethyl terephthalate over titanium(IV) isopropoxide (TTIP) as a catalyst. The corresponding DSC diagram is shown in Fig. 2A, which reveals that the melting point of polydecylene terephthalate diol (PDT) is approximately 116°C, while its crystallization temperature is approximately 94°C. The reaction of polydecylene terephthalate diol (PDT), produced as described above, with 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) and 1,4-butanediol (1,4-BD) in the molar ratio of PDT : 4,4'-MDI : 1,4-BD = 1 : 3.1 : 2.1 according to the prepolymer process yields thermoplastic polyester polyurethane with shape memory and thermoresponsive properties, which contains the soft segments based on polyester units with an average molar mass of 2900 g / mol. The corresponding DSC diagram can be found in Fig. 2B, which shows that the switching temperature of the thermoplastic polyester polyurethane is approximately 114°C, while its shape-fixing temperature is approximately 67°C. The shape recovery (after stretching with 180% elongation under heating at least to the switching temperature and subsequent cooling at least to the shape fixing temperature as well as unloading of a test specimen produced therefrom) is approximately 88%. Example 3: Production of a third embodiment of a thermoplastic polyester polyurethane with shape memory or thermoresponsive properties: Hard segments: Polyurethane units obtained by polyaddition of a diisocyanate in the form of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with a first diol serving as a chain extender in the form of 1,4-butanediol (1,4-BD); Soft segments: Polyester units based on a polyester diol in the form of polydecylene adipate diol (PDA) with a numerical mean molar mass of slightly more than 2500 g / mol, which was obtained by polycondensation of a second diol in the form of 1,10-decanediol (1,10-DD) with a dicarboxylic acid in the form of hexanedioic acid (adipic acid, AA). Polydecylene adipate diol (PDA) with an average molar mass of slightly more than 2500 g / mol is produced by the polycondensation of 1,10-decanediol with hexanedioic acid (adipic acid) using titanium(IV) isopropoxide (TTIP) as a catalyst. The corresponding DSC diagram is shown in Fig. 3A, which reveals that the melting point of polydecylene adipate diol (PDA) is approximately 70°C, while its crystallization temperature is approximately 59°C. The reaction of the polydecylene adipate diol (PDA) produced as described above with 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) and 1,4-butanediol (1,4-BD) in the molar ratio of PDA : 4,4'-MDI : 1,4-BD = 1 : 2.7 : 1.7 according to the prepolymer process yields the thermoplastic polyester polyurethane with shape memory and thermoresponsive properties, which contains the soft segments based on the polyester units with an average molar mass of slightly more than 2500 g / mol. The corresponding DSC diagram can be found in Fig. 3B, which shows that the switching temperature of the thermoplastic polyester polyurethane is approximately 59°C, while its shape-fixing temperature is approximately 31°C. The shape recovery (after stretching with 100% elongation under heating at least to the switching temperature and subsequent cooling at least to the shape fixing temperature as well as unloading of a test specimen produced therefrom) is approximately 89%. Example 4: Production of a fourth embodiment of a thermoplastic polyester polyurethane with shape memory or thermoresponsive properties: Hard segments: Polyurethane units obtained by polyaddition of a diisocyanate in the form of 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) with a first diol serving as a chain extender in the form of 1,4-butanediol (1,4-BD); Soft segments: Polyester units based on a polyester diol in the form of polydecylenesuccinate diol (PDS) with a numerical mean molar mass of slightly more than 2750 g / mol, which has been obtained by polycondensation of a second diol in the form of 1,10-decanediol (1,10-DD) with a dicarboxylic acid in the form of butanedioic acid (succinic acid, SA). Polydecylenesuccinate diol (PDS) with an average molar mass of slightly more than 2750 g / mol is produced by the polycondensation of 1,10-decanediol with butanedioic acid (succinic acid) using titanium(IV) isopropoxide (TTIP) as a catalyst. The corresponding DSC diagram is shown in Fig. 4A, which reveals that the melting point of polydecylenesuccinate diol (PDS) is approximately 67°C, while its crystallization temperature is approximately 56°C. The reaction of polydecylenesuccinate diol (PDS), produced as described above, with 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) and 1,4-butanediol (1,4-BD) in the molar ratio of PDS : 4,4'-MDI : 1,4-BD = 1 : 3.0 : 2.0 according to the prepolymer process yields thermoplastic polyester polyurethane with shape memory and thermoresponsive properties, which contains soft segments based on polyester units with an average molar mass of slightly more than 2750 g / mol. The corresponding DSC diagram can be found in Fig. 4B, which shows that the switching temperature of the thermoplastic polyester polyurethane is approximately 62°C, while its shape-fixing temperature is approximately 37°C. The shape recovery (after stretching with 100% elongation under heating at least to the switching temperature and subsequent cooling at least to the shape fixing temperature as well as unloading of a test specimen produced therefrom) is approximately 94%.

Claims

Thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, comprising: - hard segments containing polyurethane units obtained by polyaddition of the isocyanate groups of at least one diisocyanate with the hydroxyl groups of at least one first diol serving as a chain extender to form urethane groups; and - crystallizable soft segments containing polyester units, wherein the polyester units are linked to the hard segments by polyaddition of corresponding polyester diols and / or polyols with the isocyanate groups of the at least one diisocyanate to form urethane groups; and wherein the polyester diols and / or polyols are obtained by polycondensation of the hydroxyl groups of at least one second diol with at least one dicarboxylic acid or with its derivatives to form ester groups.wherein the polyester diols and / or polyols of the polyester units of the soft segments have an average molar mass between 1500 g / mol and 7000 g / mol, wherein the switching temperature of the thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, corresponding to the melting temperature of the soft segments, is at least 50°C, and wherein the shape fixing temperature of the thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties, corresponding to the crystallization temperature of the soft segments, is at least 25°C. Polyester polyurethane according to claim 1, characterized in that its switching temperature is at least 60°C and / or its mold fixing temperature is at least 30°C. Polyester polyurethane according to claim 1 or 2, characterized in that the polyester diols and / or polyols of the polyester units of the soft segments have an average molar mass of at least 2500 g / mol and / or of at most 6500 g / mol. Polyester polyurethane according to one of claims 1 to 3, characterized in that the at least one dicarboxylic acid or its derivatives, from which the polyester diols and / or polyols of the polyester units of the soft segments have been obtained, is selected from the group consisting of aliphatic dicarboxylic acids or their derivatives, in particular with 4 to 12 carbon atoms; or aromatic dicarboxylic acids or their derivatives, in particular from the group consisting of terephthalic acid, isophthalic acid, ortho-phthalic acid and 2,5-furandicarboxylic acid or their derivatives, including mixtures thereof. Polyester polyurethane according to one of claims 1 to 4, characterized in that the at least one second diol from which the polyester diols and / or polyols of the polyester units of the soft segments have been obtained is selected from the group of alkane diols. Polyester polyurethane according to one of claims 1 to 5, characterized in that the polyester units of the soft segments have at least one chain segment formed by at least one further oligomer or polymer, which is obtained in particular by reaction of at least one further hydroxy- and / or amino-terminated oligomer or polymer with the polyester diols and / or polyols, or by copolymerization of the at least one second diol with the at least one dicarboxylic acid or its derivatives and at least one further hydroxy- and / or amino-terminated oligomer or polymer, or by copolymerization of the at least one second diol with the at least one dicarboxylic acid or its derivatives and at least one further di- or polyalcohol and / or with at least one further di- or polycarboxylic acid. Polyester polyurethane according to one of claims 1 to 6, characterized in that the at least one diisocyanate from which the polyurethane units of the hard segments have been obtained is selected from the group of aromatic, aliphatic or cycloaliphatic diisocyanates. Polyester polyurethane according to one of claims 1 to 7, characterized in that the at least one first diol serving as a chain extender, from which the polyurethane units of the hard segments have been obtained, is selected from the group of alkanediols. Polyester polyurethane according to one of claims 1 to 8, characterized in that it is unbranched; or slightly branched, wherein the polyurethane units are obtained in particular by polyaddition of the isocyanate groups of at least one diisocyanate with the hydroxy groups of at least one first diol serving as a chain extender and at least one additional tri- or polyol with the isocyanate groups to form urethane groups. Polymer molded part comprising at least one thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties according to any one of claims 1 to 9 or a polymer blend with at least one such polyester polyurethane, or being entirely formed therefrom, wherein the switching temperature is at least 50°C and the mold fixing temperature is at least 25°C. Polymer molded part according to claim 10, characterized in that its shape recovery after stretching with 100% elongation under heating at least to the switching temperature of the at least one thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties is at least 80%. A process for the production of a thermoplastic polyester polyurethane according to any one of claims 1 to 9, comprising the following steps: (a) providing at least one second diol and at least one dicarboxylic acid or its derivatives; (b) reacting the at least one second diol with the at least one dicarboxylic acid or its derivatives according to step (a) to give polyester diols and / or polyols with an average molar mass between 1500 g / mol and 7000 g / mol;and (c) reacting at least one diisocyanate with at least one first diol serving as a chain extender in the presence of the polyester diols and / or polyols according to step (b) to form the polyurethane units of the hard segments by polyaddition of the isocyanate groups of the at least one diisocyanate with the hydroxy groups of the at least one second diol, and to connect the polyester units serving as soft segments to the hard segments via urethane bonds by polyaddition of the hydroxy groups of the polyester diols and / or polyols according to step (b) with the isocyanate groups of the at least one diisocyanate, thereby obtaining the thermoplastic polyester polyurethane with a switching temperature of at least 50°C and a mold fixing temperature of at least 25°C. The method according to claim 12, characterized in that in step (b) the at least one second diol is reacted with the at least one dicarboxylic acid or its derivatives to form polyester diols and / or polyols with an average molar mass of at least 2500 g / mol and / or of at most 6500 g / mol. A method according to claim 12 or 13, characterized in that: - the polyester diols and / or polyols are reacted with at least one further hydroxy- and / or amino-terminated oligomer or polymer during step (b), or - the reaction of the at least one second diol with the at least one dicarboxylic acid or its derivatives to form the polyester diols and / or polyols according to step (b) is carried out in the presence of at least one further hydroxy- and / or amino-terminated oligomer or polymer, or - the reaction of the at least one second diol with the at least one dicarboxylic acid or its derivatives to form the polyester diols and / or polyols according to step (b) is carried out in the presence of at least one further di- or polyalcohol and / or at least one further di- or polycarboxylic acid in order to introduce a chain segment formed by at least one further oligomer or polymer into the polyester units of the soft segments. Method according to one of claims 12 to 14, characterized in that the thermoplastic polyester polyurethane with shape memory properties and / or with thermoresponsive properties is at least partially deformed for programming at a temperature above 50°C, which corresponds at least to the switching temperature of the thermoplastic polyester polyurethane, after which it is cooled at least to its shape fixing temperature of at least 25°C and relieved.

Images