Process for preparing polyether-containing thermoplastic polyurethanes

Abstract

The present invention relates to a process for preparing polyether-containing thermoplastic polyurethanes and to polyether-containing thermoplastic polyurethanes obtained or obtainable by these processes. The invention further relates to the use of these polyether-containing thermoplastic polyurethanes and to articles comprising or consisting of the polyether-containing thermoplastic polyurethane. The invention moreover relates to the use of a C3 polyether homopolymer polyol in combination with a C2 polyether homopolymer polyol and / or a C2 / C3 polyether block copolymer polyol and / or C4 polyether homopolymer polyol, preferably of a C3 polyether homopolymer polyol in combination with a C2 / C3 polyether block copolymer polyol, for increasing the low-temperature impact strength and / or the tensile strength of polyether-containing thermoplastic polyurethanes.

Description

[0001] Process for the preparation of polyether-containing thermoplastic polyurethanes

[0002] The present invention relates to a process for producing polyether-containing thermoplastic polyurethanes, as well as to polyether-containing thermoplastic polyurethanes obtained or obtainable by these processes. Furthermore, the invention relates to the use of these polyether-containing thermoplastic polyurethanes and articles comprising or consisting of the polyether-containing thermoplastic polyurethane. Furthermore, the invention relates to the use of a C3 polyether homopolymer polyol in combination with a C2 polyether homopolymer polyol and / or a C2 / C3 polyether block copolymer polyol and / or a C4 polyether homopolymer polyol, preferably a C3 polyether homopolymer polyol in combination with a C2 / C3 polyether block copolymer polyol, for increasing the low-temperature impact strength and / or the tensile strength of polyether-containing thermoplastic polyurethanes.

[0003] State of the art

[0004] Thermoplastic polyurethanes (TPUs) have been around for a long time. They are of great technical importance due to their combination of high-quality mechanical properties with the well-known advantages of cost-effective thermoplastic processability. By using different chemical components, a wide range of mechanical properties can be achieved. An overview of TPUs, their properties, and applications can be found, for example, in Kunststoffe 68 (1978), pages 819 to 825, or Kautschuk, Gummi, Kunststoffe 35 (1982), pages 568 to 584. TPUs are composed of linear polyols, usually polyethers or polyesters, organic diisocyanates, and short-chain diols (chain extenders). TPUs are usually solvent-free and can be produced continuously or batchwise.The best-known technical manufacturing processes, which are also used commercially, are the belt process (GB 1057018 A) and the extrusion process (DE 1964834 A1 and DE 2059570 A1). To adjust the properties, the components can be varied within a relatively wide molar ratio. Molar ratios of macrodiols to chain extenders of 1:1 to 1:12 have proven effective. The hardness of the TPU can be adjusted within a wide range by varying the amount of chain extender. This results in products with hardnesses ranging from approximately 40 Shore A to approximately 85 Shore D.

[0005] To improve processing performance, especially cycle time, TPUs that exhibit a very high solidification rate after processing in injection-molded articles are of particular interest across the entire hardness range from approximately 40 Shore A to approximately 85 Shore D. Especially with hard TPUs and soft TPUs, problems often arise with the chemical coupling of the hard and soft segments due to excessive polarity differences between these phases. As a result, the full potential of the mechanical properties and processing characteristics cannot often be fully exploited. There has been no shortage of attempts to overcome these disadvantages using special processes.

[0006] A process for producing thermoplastically processable polyurethanes is described by W. Bräuer et al. (EP-A 1757632). A multi-stage OH prepolymer process improves the homogeneity of the TPU. However, this improved homogeneity slows the solidification rate of the TPU.

[0007] A process for producing soft, easily demolded thermoplastic polyurethane elastomers with low shrinkage is described by W. Bräuer et al. (EP-A 1338614). The demolding behavior of TPUs with hardnesses between 45 Shore A and 65 Shore A was improved by pre-extension of the soft segments. At very high hardnesses, this process has significant disadvantages because incompatibilities between the hard and soft phases arise, preventing good coupling of these phases. As a result, the high molecular weight of the TPU required for good mechanical properties is not achieved. In practice, this process is also very unstable due to excessively high and fluctuating viscosities of the prepolymer stage, and it no longer functions satisfactorily below 60 Shore A, frequently leading to extruder downtimes.

[0008] To improve the low-temperature impact strength of, for example, polyester-based TPUs for ski boot applications, polyether polyols with a molecular weight greater than 1600 g / mol are used as modifiers, such as polytetramethylene ether glycol (US4980445A) and polypropylene diol ether (WO / 2018 / 158327). Due to the incompatibility of the hard and soft phases in the TPU, which leads to poor coupling between these phases, such polyethers are difficult to incorporate as a pure soft phase into TPUs harder than 60 Shore D. A hard TPU with good low-temperature impact strength is difficult to produce without a modifier.

[0009] The use of polypropylene glycol or poly(propylene oxide) homopolymers (hereinafter also referred to as C3 polyether homopolymer polyol) as a polyol component in the production of thermoplastic polyurethanes is interesting, among other things, due to its low cost. The use of polypropylene glycol in the production of thermoplastic polyurethanes is known, for example, from WO 2020 / 109566 A1, in which polyols based on polypropylene glycol are reacted with polyisocyanates.

[0010] A disadvantage of using polypropylene glycol as a polyol component, however, is that only thermoplastic polyurethanes with relatively low Shore A or theoretical hardness values ​​can be produced, which exhibit sufficient mechanical properties and abrasion resistance. Hard thermoplastic polyurethanes based on polypropylene glycol usually exhibit these typical properties only to a limited extent or not at all, making them unsuitable for applications requiring significantly harder materials. Furthermore, these types of thermoplastic polyurethanes exhibit low low-temperature impact strength, which also precludes their use in articles exposed to low temperatures.

[0011] Object of the invention

[0012] The object of the present invention was therefore to provide a process for producing polyether-containing thermoplastic polyurethanes with improved mechanical properties, in particular with increased hardness or increased tensile strength and / or low-temperature impact strength. In particular, a process for the more cost-effective production of polyether-containing thermoplastic polyurethanes is to be provided, which preferably has an improved CCE balance. Solution to the problem

[0013] This object is achieved by a process for the preparation of polyether-containing thermoplastic polyurethanes by reacting a composition comprising or consisting of the following components:

[0014] (A) at least one polyether homopolymer polyol

[0015] (B) at least one polyisocyanate;

[0016] (C) at least one chain extender;

[0017] (D) optionally a catalyst;

[0018] (E) optionally at least one additive, auxiliary and / or additional substance; characterized in that the polyether homopolymer polyol is a C3 polyether homopolymer polyol (A1) and component (A) additionally contains at least one component (A2) comprising or consisting of a C2 polyether homopolymer polyol and / or a C2 / C3 polyether block copolymer polyol and / or a C4 polyether homopolymer polyol, wherein the mass ratio of component (A1) to (A2) is from 95:5 to 25:75, based on the total mass of components (A1) and (A2).

[0019] Furthermore, the invention relates to a polyether-containing thermoplastic polyurethane obtained or obtainable by the process according to the invention.

[0020] The invention further relates to the use of the polyether-containing thermoplastic polyurethane according to the invention for producing injection-molded articles; extruded articles; pressed articles; compression-molded articles; 3D-printed articles; articles for mechanical engineering, road and rail construction; medical and dental articles, in particular splints for treating malocclusions; shoes, in particular ski boots; articles for the automotive industry; articles for the electrical industry, in particular cable sheathing, housings and plugs; consumer articles; coatings; hoses; profiles; belts; films; fibers; nonwovens; textiles; damping elements; sealing materials.

[0021] Furthermore, the invention relates to an article comprising or consisting of the polyether-containing thermoplastic polyurethane according to the invention, wherein the article is preferably a ski boot. Finally, the invention relates to the use of a C3 polyether homopolymer polyol in combination with a C2 polyether homopolymer polyol and / or a C2 / C3 polyether block copolymer polyol and / or a C4 polyether homopolymer polyol for increasing the Charpy impact strength and / or the tensile strength of polyether-containing thermoplastic polyurethanes, in particular of polyether-containing thermoplastic polyurethanes according to the invention, wherein the low-temperature impact strength is determined in particular as Charpy impact strength.

[0022] Surprisingly, it has been found that when the polyether homopolymer polyol used in the production of polyether-containing thermoplastic polyurethanes is a C3 polyether homopolymer polyol, the mechanical properties, in particular the hardness or tensile strength and / or low-temperature impact strength, of these polyurethanes can be improved by using, in addition to the C3 polyether homopolymer polyol, additional C2 polyether homopolymer polyols and / or C2 / C3 polyether block copolymer polyols and / or C4 polyether homopolymer polyols.

[0023] For the purposes of this invention, C2 polyether homopolymer polyol is understood to mean a polyol based on polyethylene glycol or poly(ethylene oxide); C3 polyether homopolymer polyol is understood to mean a polyol based on polypropylene glycol or poly(propylene oxide); C2 / C3 polyether block copolymer polyol is understood to mean a polyol based on polyethylene glycol or poly(ethylene oxide) and polypropylene glycol or poly(propylene oxide); and C4 polyether homopolymer polyol is understood to mean a polyol based on polytetramethylene glycol. The "C" in "C2," "C3," etc., stands for a carbon atom, with the number following it indicating the number of carbon atoms in the repeating unit of the respective polymer.

[0024] It is particularly preferred that the polyether homopolymer polyol is a C3 polyether homopolymer polyol (Al).

[0025] The process according to the invention can be conducted batchwise or continuously, with continuous operation being preferred, especially on an industrial scale (for example, as an inline one-shot process). Furthermore, it is preferred that the process be carried out solvent-free. Other possible preparation processes include, for example, the so-called prepolymer process, MDI splitting, or the 3-stage equivalent prepolymer process, which are generally known to the person skilled in the art.

[0026] In the method according to the invention, the

[0027] • C2 polyether homopolymer polyol has a number average molecular weight in the range from 500 to 4000 g / mol, preferably 1000 to 3000 g / mol;

[0028] • C3 polyether homopolymer polyol has a number average molecular weight in the range from 500 to 8000 g / mol, preferably 1000 to 4500 g / mol;

[0029] • C2 / C3 polyether block copolymer polyol has a number-average molecular weight in the range from 1000 to 4000 g / mol, preferably 1500 to 2500 g / mol; and / or

[0030] • C4 polyether homopolymer polyol has a number average molecular weight in the range from 500 to 4500 g / mol, preferably 1500 to 4500 g / mol.

[0031] In a further embodiment of the process according to the invention, the theoretical hardness of the polyether-containing thermoplastic polyurethane is > 40%, whereby the theoretical hardness is calculated using the following formula:

[0032] Theoretical hardness = (n(chain extender)*M(polyisocyanate)+m(chain extender)) / m g total with n = amounts of substance of the components, M = molar mass of the components and m = masses of the components.

[0033] Within the scope of the invention, it is further preferred that the molar ratio of the ethylene oxide building blocks to propylene oxide building blocks in the C2 / C3 polyether block copolymer polyol is 95:5 to 5:95, preferably 80:20 to 20:80, based on the molar amounts of the alkylene oxides used in the polyether preparation.

[0034] Furthermore, it is preferred that the mass ratio of component (Al) to (A2) is from 65:35 to 30:70, based on the total mass of components (Al) and (A2).

[0035] Furthermore, it is preferred that the polyisocyanate of component (B) is 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-

[0036] Diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, isophorone diisocyanate, naphthylene-1,5-diisocyanate, 1,1'-methylenebis(4-isocyanatocyclohexane) or mixtures thereof, preferably 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-

[0037] comprising or consisting of diphenylmethane diisocyanate or mixtures thereof.

[0038] Preferably, the chain extender of component (C) is selected from the group comprising or consisting of 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-di-(beta-hydroxyethyl)hydroquinone, triethylene glycol, tetraethylene glycol or mixtures thereof, preferably 1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol, triethylene glycol or mixtures thereof.

[0039] The catalysts (D) used can be the conventional catalysts known from polyurethane chemistry. Suitable catalysts are known and conventional tertiary amines, such as triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol,

[0040] Diazabicyclo-[2,2,2]-octane, and similar and especially organic metal compounds such as titanic acid esters, iron compounds, bismuth compounds, tin compounds, e.g. tin diacetate, tin dioctoate, tin dilaurate or the

[0041] Tin dialkyl salts of aliphatic carboxylic acids such as dibutyltin diacetate,

[0042] Dibutyltin dilaurate or similar. Preferred catalysts are organic

[0043] Metal compounds, especially titanic acid esters, iron or tin compounds. Dibutyltin dilaurate, tin dioctoate, and titanic acid esters are particularly preferred.

[0044] Additives, auxiliaries, and additives (E) that can be used include, for example, lubricants such as fatty acid esters, their metal soaps, fatty acid amides, and silicone compounds, antiblocking agents, inhibitors, stabilizers against hydrolysis, light, heat, and discoloration, flame retardants, dyes, pigments, inorganic or organic fillers, nucleating agents, reinforcing agents, and monofunctional chain terminators. Reinforcing agents are, in particular, fibrous reinforcing materials such as inorganic fibers, which are manufactured using state-of-the-art technology and may also be coated with a size. Monofunctional chain terminators that can be used to adjust a specific TPU molecular weight include monoalcohols such as 1-butanol, 1-hexanol, 1-octanol, and stearyl alcohol, or monoamines such as 1-butylamine and stearylamine. Further information on the aforementioned auxiliaries and additives can be found in the specialist literature, for example, JH Saunders, K.C. Frisch: High Polymers, Volume XVI, Polyurethanes, Parts 1 and 2, Interscience Publishers 1962 and 1964, respectively, R.Gächter, H.Müller (Ed.): Handbook of Plastics Additives, 3rd Edition, Hanser Verlag, Munich 1989, or DE-A 29 01 774.

[0045] It is further preferred that the process comprises or consists of the following steps: i) reacting a mixture of the total amount of component (A), a

[0046] Partial amount of component (B) and optionally a partial amount or the total amount of component (D) and / or (E) to an NCO-functional prepolymer, wherein a molar ratio of

[0047] (Partial) component (B) to component (A) is in the range from 1.1:1.0 to 5.0:1.0; ii) reacting the NCO-functional prepolymer from step i) with the total amount of component (C) to obtain an OH-functional prepolymer, optionally in the presence of a further partial amount or the remaining amount of component (D) and / or (E); iii) reacting the OH-functional prepolymer from step ii) with the remaining amount of component (B) and optionally the remaining amount of component (D) and / or (E) to obtain the polyether-containing thermoplastic polyurethane; wherein in step ii) there is preferably a molar ratio of NCO-functional groups to OH-functional groups of component (C) of less than 1.0.

[0048] The reaction is preferably carried out at an isocyanate index of 0.9 to 1.2, more preferably from 0.95 to 1.1, and particularly preferably from 0.97 to 1.03. The isocyanate index (also called index, NCO / OH index, or isocyanate index) is understood here as the quotient of the actual amount of isocyanate groups used [mol] and the actual amount of isocyanate-reactive groups used [mol]. In other words, the index indicates the percentage ratio of the actual amount of isocyanate used to the stoichiometric amount of isocyanate, i.e., the amount calculated for the conversion of the OH equivalents. An equivalent amount of NCO groups and NCO-reactive H atoms corresponds to an NCO / OH index of 1. The isocyanate index is calculated using the following formula: Index = [(mol isocyanate groups) / (mol isocyanate-reactive groups)]

[0049] The polyether-containing thermoplastic polyurethane according to the invention preferably has

[0050] • a tensile strength of at least 17 MPa, preferably at least 22 to 60 MPa, measured according to ISO 53504 (2009-10); and / or

[0051] • a Charpy impact strength of at least 30 KJ / m 2 , preferably 50 to 140 KJ / m 2 , measured at -20 °C according to DIN EN ISO 179 / 1 eA (2010).

[0052] The Charpy impact strength measured at -20 °C according to DIN EN ISO 179 / leA (2010) is understood in the context of this invention as a measure of low-temperature impact strength. The injection-molded parts are subjected to Charpy impact strength tests according to DIN EN ISO 179 / leA (2010) at -20 °C. The test specimen has the following dimensions: 80 ± 2 mm length, 10.0 ± 0.2 mm width, and 4.0 ± 0.2 mm thickness. The test specimen is notched. The notch root radius rN is 0.25 ± 0.05 mm.

[0053] Embodiments:

[0054] The present invention particularly relates to the following embodiments:

[0055] According to a first embodiment, the invention relates to a process for the preparation of polyether-containing thermoplastic polyurethanes by reacting a composition comprising or consisting of the following components:

[0056] (A) at least one polyether homopolymer polyol

[0057] (B) at least one polyisocyanate;

[0058] (C) at least one chain extender;

[0059] (D) optionally a catalyst,

[0060] (E) optionally at least one additive, auxiliary and / or additional substance; characterized in that the polyether homopolymer polyol is a C3 polyether homopolymer polyol (A1) and component (A) additionally contains at least one component (A2) comprising or consisting of a C2 polyether homopolymer polyol and / or a C2 / C3 polyether block copolymer polyol and / or a C4 polyether homopolymer polyol, wherein the mass ratio of component (A1) to (A2) is from 95:5 to 25:75, based on the total mass of components (A1) and (A2).

[0061] According to a second embodiment, the invention relates to a method according to embodiment 1, characterized in that the

[0062] • C2 polyether homopolymer polyol has a number average molecular weight in the range from 500 to 4000 g / mol, preferably 1000 to 3000 g / mol;

[0063] • C3 polyether homopolymer polyol has a number average molecular weight in the range from 500 to 8000 g / mol, preferably 1000 to 4500 g / mol;

[0064] • C2 / C3 polyether block copolymer polyol has a number-average molecular weight in the range from 1000 to 4000 g / mol, preferably 1500 to 2500 g / mol; and / or

[0065] • C4 polyether homopolymer polyol has a number average molecular weight in the range from 500 to 4500 g / mol, preferably 1500 to 4500 g / mol.

[0066] According to a third embodiment, the invention relates to a process according to embodiment 1 or 2, characterized in that the theoretical hardness of the polyether-containing thermoplastic polyurethane is > 40%, wherein the theoretical hardness is calculated using the following formula:

[0067] Theoretical hardness =

[0068] (n(chain extender)*M(polyisocyanate)+m(chain extender)) / m gesami with n = amounts of substances of the components, M = molar mass of the components and m = masses of the components

[0069] According to a fourth embodiment, the invention relates to a process according to one of the preceding embodiments, characterized in that the molar ratio of the ethylene oxide units to propylene oxide units in the C2 / C3 polyether block copolymer polyol is 95:5 to 5:95, preferably 80:20 to 20:80, based on the molar amounts of the alkylene oxides used in the polyether preparation. According to a fifth embodiment, the invention relates to a process according to one of the preceding embodiments, characterized in that the mass ratio of component (A1) to (A2) is 65:35 to 30:70, based on the total mass of components (A1) and (A2).

[0070] According to a sixth embodiment, the invention relates to a process according to one of the preceding embodiments, characterized in that the polyisocyanate of component (B) is 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, isophorone diisocyanate, naphthylene-1,5-diisocyanate, 1,1'-methylenebis(4-isocyanatocyclohexane) or mixtures thereof, preferably 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-

[0071] comprising or consisting of diphenylmethane diisocyanate or mixtures thereof.

[0072] According to a seventh embodiment, the invention relates to a process according to one of the preceding embodiments, characterized in that the chain extender of component (C) is selected from the group comprising or consisting of 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-di-(beta-hydroxyethyl)hydroquinone, triethyl englycol, tetraethylene glycol or mixtures thereof, preferably 1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol, triethyl englycol or mixtures thereof.

[0073] According to an eighth embodiment, the invention relates to a process according to one of the preceding embodiments, characterized in that the additive, the auxiliary and / or the additive of component (E) is selected from the group comprising or consisting of lubricants, in particular fatty acid esters, their metal soaps, fatty acid amides and silicone compounds; antiblocking agents; inhibitors; stabilizers; flame retardants; dyes; pigments; inorganic fillers; organic fillers; nucleating agents; reinforcing agents, in particular inorganic fibers; monofunctional chain terminators, in particular 1-butanol, 1-hexanol, 1-octanol, stearyl alcohol, 1-butylamine and stearylamine; or mixtures thereof.

[0074] According to a ninth embodiment, the invention relates to a process according to one of the preceding embodiments, characterized in that the process comprises or consists of the following steps: i) reacting a mixture of the total amount of component (A), a partial amount of component (B) and optionally a partial amount or the total amount of component (D) and / or (E) to form an NCO-functional prepolymer, wherein a molar ratio of partial component (B) to component (A) is in the range from 1.1:1.0 to 5.0:1.0; ii) reacting the NCO-functional prepolymer from step i) with the total amount of component (C) to obtain an OH-functional prepolymer, optionally in the presence of a further partial amount or the remaining amount of component (D) and / or (E);iii) reacting the OH-functional prepolymer from step ii) with the remaining amount of component (B) and optionally the remaining amount of component (D) and / or (E) to obtain the polyether-containing thermoplastic polyurethane; wherein in step ii) the molar ratio of NCO-functional groups to OH-functional groups of component (C) is preferably less than 1.0.

[0075] According to a tenth embodiment, the invention relates to a process according to one of the preceding embodiments, characterized in that the reaction is carried out at an isocyanate number of 0.9 to 1.2, preferably of 0.95 to 1.1, more preferably of 0.97 to 1.03.

[0076] According to an eleventh embodiment, the invention relates to a polyether-containing thermoplastic polyurethane obtained or obtainable by a process according to any one of embodiments 1 to 10.

[0077] According to a twelfth embodiment, the invention relates to a polyether-containing thermoplastic polyurethane according to embodiment 11, characterized in that the polyether-containing thermoplastic polyurethane

[0078] • a tensile strength of at least 17 MPa, preferably at least 22 to 60 MPa, measured according to ISO 53504 (2009-10); and / or a Charpy impact strength of at least 30 KJ / m 2 , preferably 50 to 140 KJ / m 2 , measured at -20 °C according to DIN EN ISO179 / leA (2010).

[0079] According to a thirteenth embodiment, the invention relates to the use of the polyether-containing thermoplastic polyurethane according to embodiment 11 or 12 for the production of injection-molded articles; extrusion articles; pressed articles, compression-molded articles; 3D-printed articles; articles for mechanical engineering, road and rail construction; medical and dental articles, in particular splints for the treatment of malocclusions; shoes, in particular ski boots; articles for the automotive industry; articles for the electrical industry, in particular cable sheathing, housings and plugs; consumer articles; coatings; hoses; profiles; belts; films; fibers; nonwovens; textiles; damping elements, sealing materials.

[0080] According to a fourteenth embodiment, the invention relates to an article which comprises or consists of a polyether-containing thermoplastic polyurethane according to embodiment 11 or 12, wherein the article is preferably a ski boot.

[0081] According to a fifteenth embodiment, the invention relates to the use of a C3 polyether homopolymer polyol in combination with a C2 polyether homopolymer polyol and / or a C2 / C3 polyether block copolymer polyol and / or a C4 polyether homopolymer polyol for increasing the low-temperature impact strength and / or the tensile strength of polyether-containing thermoplastic polyurethanes, in particular of polyether-containing thermoplastic polyurethanes according to embodiment 11 or 12, wherein the low-temperature impact strength is determined in particular as Charpy impact strength.

[0082] Examples and comparison examples:

[0083] The present invention is discussed below with reference to examples, but is not limited to them.

[0084] Components used:

[0085] • Polyol 1 = polypropylene glycol (C3 polyether homopolymer polyol), starter propylene glycol (poly(propylene oxide) homopolymer); OH number approx. 56: proportion of secondary terminal OH groups: >90%;

[0086] • Polyol 2 = Terathane®2000 (commercial product from Invista:

[0087] Polytetramethylene glycol; OH number approx. 56), (C4 polyether homopolymer polyol);

[0088] • Polyol 3 = Poly(propylene oxide)-poly(ethylene oxide) block copolymer (C2 / C3-

[0089] Polyether block copolymer polyol): Propylene glycol (starter) with polymerized alkylene oxides (molar ratio of ethylene oxide units to propylene oxide units of approximately 51:49); OH number approximately 56, proportion of primary terminal OH groups: >90%), KOH catalyzed

[0090] • Polyol 4 = polypropylene glycol (C3 polyether homopolymer polyol), starter propylene glycol (poly(propylene oxide) homopolymer), OH number approx. 28: proportion of secondary terminal OH groups: >90%)

[0091] • BDO = 1,4-butanediol (BDO, purity > 99 wt%) was purchased from Ashland.

[0092] • TEG = Triethyl englycol (TEG, purity > 95 wt%) was purchased from Thermo Fischer (Kandel) GmbH.

[0093] • MDI = 4,4'-diphenylmethane diisocyanate (MDI, purity > 99 wt%) was purchased from Covestro AG.

[0094] Measurement methods used:

[0095] • Titration of the OH numbers according to DIN 53240-2:2007-11

[0096] • Tensile test: Measurement according to ISO 53504 (2009-10) with a tensile speed of 200 mm / min;

[0097] • Charpy impact strength test (low-temperature impact strength): The injection-molded parts were subjected to Charpy impact strength tests according to DIN EN ISO179 / leA (2010) at -20°C. The test specimen has the following dimensions: 80±2mm length, 10.0±0.2mm width, and 4.0±0.2mm thickness. The test specimen is notched. The notch root radius rN is 0.25±0.05mm; examples:

[0098] Table 1 illustrates the invention with some examples. The manufacturing processes used are described below.

[0099] Production (discontinuous process):

[0100] Step 1: Partial amount 1 (see Table 1) of the MDI is brought to a conversion of > 90 mol-%, based on the polyol, at approx. 140°C with 1 mol of polyol or polyol mixture while stirring.

[0101] Step 2: The chain extender is added to the stirred reaction mixture and stirred intensively for approximately 10 seconds.

[0102] Step 3: Part 2 (see Table 1) of the MDI is added to the stirred reaction mixture. The reaction mixture is stirred for another 20 seconds, then poured onto a tray and annealed at 120°C for 30 minutes.

[0103] The resulting TPU cast sheets were cut and granulated. The granules were processed into rods (mold temperature: 40°C; rod size: 80x10x4 mm) or sheets (mold temperature: 70°C; size: 125x50x2 mm) using an Arburg Allrounder 470S injection molding machine at a temperature range of 180°C to 230°C and a pressure range of 650 to 750 bar with an injection flow rate of 10 to 35 cm3 / s.

[0104] The mechanical values ​​(tensile strength and tensile elongation) as well as the low-temperature impact strength according to Charpy were determined for the TPU products manufactured.

[0105] Examples 1-18 describe discontinuous processes.

[0106] Production (continuous process e.g. reaction extruder):

[0107] Analogous to the discontinuous experiments, the TPU can also be produced continuously, for example using a twin-screw reaction extruder (however, production is not limited to this method, see “belt process”). A gear pump was used to meter portion 1 of the MDI, preheated to 60°C, into a tube equipped with a spiked mixer. A second gear pump pumped a polyol or polyol mixture heated to 140°C into the same tube. The tube had a length / diameter ratio of 8:1. The reaction mixture flowed continuously into a connected twin-screw extruder, which was externally heated to 140°C to 220°C. The chain extender and portion 2 of the MDI were added in the middle of the screw. The screw shaft ran at 300 rpm. At the end of the screw, the hot melt was granulated and cooled.The granules were injection molded into test specimens, on which the properties listed in the table were measured. Example 19 describes a continuous process (extruder process).

[0108] Table 1:

[0109] * Comparative example not according to the invention; ** No processing possible;

[0110] # Theoretical hardness (TH) is the weight fraction of the hard segment in the TPU: TH = (n(KV)*M(ISO)+m(KV)) / m ges with KV = chain extender and ISO = isocyanate (here MDI)

[0111] - Comparative examples 1 and 18 are TPU formulations based on polypropylene glycol (C3 polyether homopolymer polyol), the TPUs cannot be produced and / or processed by injection molding

[0112] - Comparative examples 3 and 5-7 are formulations based on polypropylene polyethylene glycol (C2 / C3 polyether block copolymer polyol), which represent TPU with good tear resistance but poor low-temperature impact strength.

[0113] - Examples 4, 8-13, 15-17 show TPU formulations with C2 / C3 polyether block copolymer polyol mixed with C3 polyether homopolymer polyol with good tear strength and good low-temperature impact strength (Charpy impact strength).

[0114] - Comparative Example 14 shows a TPU formulation based on C2 / C3 polyether block copolymer polyol mixed with polypropylene glycol (C3 polyether homopolymer polyol) in a ratio of approximately 80:20; the material shows good tear strength, but not satisfactory low-temperature impact strength

[0115] - Example 2 shows a TPU formulation based on C3 ether polyol and a Cd polyether homopolymer polyol (also polyTHF or PTMEG) with good mechanical properties and good low-temperature impact strength.

[0116] - Example 19 shows that the process according to the invention also leads to good tear resistance with simultaneously good low-temperature impact strength of the polyether-containing thermoplastic polyurethane produced in a continuous process.

Claims

Patent claims 1. A process for the preparation of polyether-containing thermoplastic polyurethanes by reacting a composition comprising or consisting of the following components: (A) at least one polyether homopolymer polyol (B) at least one polyisocyanate; (C) at least one chain extender; (D) optionally a catalyst; (E) optionally at least one additive, auxiliary and / or additional substance; characterized in that the polyether homopolymer polyol is a C3 polyether homopolymer polyol (A1) and component (A) additionally contains at least one component (A2) comprising or consisting of a C2 polyether homopolymer polyol and / or a C2 / C3 polyether block copolymer polyol and / or a C4 polyether homopolymer polyol, wherein the mass ratio of component (A1) to (A2) is from 95:5 to 25:75, based on the total mass of components (A1) and (A2).

2. Method according to claim 1, characterized in that the • C2 polyether homopolymer polyol has a number average molecular weight in the range from 500 to 4000 g / mol, preferably 1000 to 3000 g / mol; • C3 polyether homopolymer polyol has a number average molecular weight in the range from 500 to 8000 g / mol, preferably 1000 to 4500 g / mol; • C2 / C3 polyether block copolymer polyol has a number-average molecular weight in the range from 1000 to 4000 g / mol, preferably 1500 to 2500 g / mol; and / or • C4 polyether homopolymer polyol has a number average molecular weight in the range from 500 to 4500 g / mol, preferably 1500 to 4500 g / mol. Process according to claim 1 or 2, characterized in that the theoretical hardness of the polyether-containing thermoplastic polyurethane is > 40%, the theoretical hardness being calculated using the following formula: Theoretical hardness = (n(chain extender)*M(polyisocyanate)+m(chain extender)) / m gesami with n = molar amounts of the components, M = molar mass of the components, and m = masses of the components. Process according to one of the preceding claims, characterized in that the molar ratio of the ethylene oxide building blocks to propylene oxide building blocks in the C2 / C3 polyether block copolymer polyol is 95:5 to 5:95, preferably 80:20 to 20:80, based on the molar amounts of the alkylene oxides used in the polyether preparation. Process according to one of the preceding claims, characterized in that the mass ratio of component (A1) to (A2) is 65:35 to 30:70, based on the total mass of components (A1) and (A2). Process according to one of the preceding claims, characterized in that the polyisocyanate of component (B) is 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, Isophorone diisocyanate, naphthylene 1,5-diisocyanate, 1,4-methylenebis(4-isocyanatocyclohexane) or mixtures thereof, preferably 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate or mixtures thereof. Process according to one of the preceding claims, characterized in that the chain extender of component (C) is selected from the group comprising or consisting of 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-di-(beta-hydroxyethyl)hydroquinone, Triethylene glycol, tetraethylene glycol, or mixtures thereof, preferably 1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol, triethylene glycol, or mixtures thereof. The process according to any one of the preceding claims, characterized in that the additive, auxiliary, and / or additive of component (E) is selected from the group comprising or consisting of lubricants, in particular fatty acid esters, their metal soaps, fatty acid amides, and silicone compounds; antiblocking agents; inhibitors; stabilizers; flame retardants; dyes; pigments; inorganic fillers; organic fillers; nucleating agents; reinforcing agents, in particular inorganic fibers; monofunctional chain terminators, in particular 1-butanol, 1-hexanol, 1-octanol, stearyl alcohol, 1-butylamine, and stearylamine; or mixtures thereof.Process according to one of the preceding claims, characterized in that the process comprises or consists of the following steps: i) reacting a mixture of the total amount of component (A), a. Partial amount of component (B) and optionally a partial amount or the total amount of component (D) and / or (E) to form an NCO-functional prepolymer, wherein a molar ratio of (Partial) component (B) to component (A) is in the range from 1.1:1.0 to 5.0:1.0; ii) reacting the NCO-functional prepolymer from step i) with the total amount of component (C) to obtain an OH-functional prepolymer, optionally in the presence of a further partial amount or the remaining amount of component (D) and / or (E); iii) reacting the OH-functional prepolymer from step ii) with the remaining amount of component (B) and optionally the remaining amount of component (D) and / or (E) to obtain the polyether-containing thermoplastic polyurethane; wherein in step ii) there is preferably a molar ratio of NCO-functional groups to OH-functional groups of component (C) of less than 1.

0.

10. Process according to one of the preceding claims, characterized in that the reaction is carried out at an isocyanate number of 0.9 to 1.2, preferably of 0.95 to 1.1, more preferably of 0.97 to 1.

03.

11. Polyether-containing thermoplastic polyurethane obtained or obtainable by a process according to any one of claims 1 to 10.

12. Polyether-containing thermoplastic polyurethane according to claim 11, characterized in that the polyether-containing thermoplastic polyurethane • a tensile strength of at least 17 MPa, preferably at least 22 to 60 MPa, measured according to ISO 53504 (2009-10); and / or • a Charpy impact strength of at least 30 KJ / m 2 , preferably 50 to 140 KJ / m 2 , measured at -20 °C according to DIN EN ISO179 / leA (2010).

13. Use of the polyether-containing thermoplastic polyurethane according to claim 11 or 12 for the production of injection-molded articles; extruded articles; pressed articles; compression-molded articles; 3D-printed articles; articles for mechanical engineering, road and rail construction; medical and dental articles, in particular splints for the treatment of malocclusions; shoes, in particular ski boots; articles for the automotive industry; articles for the electrical industry, in particular cable sheathing, housings and plugs; consumer articles; coatings; hoses; profiles; belts; films; fibers; nonwovens; textiles; damping elements; sealing materials.

14. An article comprising or consisting of a polyether-containing thermoplastic polyurethane according to claim 11 or 12, wherein the article is preferably a ski boot.

15. Use of a C3 polyether homopolymer polyol in combination with a C2 polyether homopolymer polyol and / or a C2 / C3 polyether block copolymer polyol and / or a C4 polyether homopolymer polyol for increasing the low-temperature impact strength and / or the tensile strength of polyether-containing thermoplastic polyurethanes, in particular of polyether-containing thermoplastic polyurethanes according to claim 11 or 12, wherein the low-temperature impact strength is determined in particular as Charpy impact strength.

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