Method for producing polyether-containing thermoplastic polyurethanes

Abstract

The invention relates to a method for producing polyether-containing thermoplastic polyurethanes, and to polyether-containing thermoplastic polyurethanes obtained or obtainable by said method. The invention also relates to the use of the polyether-containing thermoplastic polyurethanes and to articles comprising or consisting of the polyether-containing thermoplastic polyurethanes. Furthermore, the present invention relates to a C3 polyether homopolymer polyol when combined 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 when combined with a C2 / C3 polyether block copolymer polyol, use for increasing the low-temperature impact strength and / or tensile strength of polyether-containing thermoplastic polyurethanes.

Description

[0001] The present invention relates to a method for preparing a thermoplastic polyurethane containing polyether, and a thermoplastic polyurethane containing polyether obtained or obtainable by the method. The present invention also relates to the use of these thermoplastic polyurethanes containing polyether and an article containing or consisting of the thermoplastic polyurethane containing polyether. In addition, the present 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 improving the low-temperature impact strength and / or tensile strength of a thermoplastic polyurethane containing polyether. Prior art

[0002] Thermoplastic polyurethanes (TPU) have long been known. They are of great industrial importance due to the combination of high mechanical properties with the known advantages of cost-effective thermoplastic processability. A wide range of mechanical properties can be achieved by using different chemical structural components. An overview of TPU, its properties and applications is described, for example, in Kunststoffe 68 (1978), pages 819 to 825 or Kautschuk, Gummi, Kunststoffe 35 (1982), pages 568 to 584. TPU is formed from linear polyols (usually polyethers or polyesters), organic diisocyanates and short-chain diols (chain extenders). TPU is usually solvent-free and can be prepared continuously or discontinuously. The most famous and industrially used industrial preparation methods are the belt method (GB 1057018 A) and the extruder method (DE 1964834 A-1 and DE 2059570 A-1).

[0003] In order to adjust the properties, the structural components can be varied within a relatively wide molar ratio. A molar ratio of macromolecular diol to chain extender of 1:1 to 1:12 has proven to be useful. The hardness of the TPU can be adjusted within a wide range via the amount of chain extender. This results in a product hardness range of about 40 Shore A to about 85 Shore D.

[0004] For improving the processing behavior, in particular the cycle times, those TPUs which have very high curing speeds after the processing process in the case of injection-molded articles are of particular interest throughout the hardness range of about 40 Shore A to about 85 Shore D. In the case of hard and soft TPUs in particular, the chemical coupling of hard and soft segments is often problematic due to the excessively large polarity differences between these phases. As a result, the overall potential of the mechanical properties and processing properties is often not fully exploited. Attempts have been made to eliminate these disadvantages by specific methods.

[0005] W. et al. (EP-A 1757632) describe a method for preparing thermoplastic processable polyurethanes. The homogeneity of the TPU is improved by a multistage OH prepolymer process. However, the improvement in homogeneity reduces the curing speed of the TPU.

[0006] W. et al. (EP-A 1 338 614) describe a process for preparing soft, easily demouldable thermoplastic polyurethane elastomers with low shrinkage. The demoulding behavior of TPUs of 45 to 65 Shore A is improved by pre-extension of the soft segments. At very high hardnesses, this process has significant disadvantages, since incompatibilities occur between the hard and soft phases, so that good coupling between these phases can no longer occur. As a result, the high molecular weights of the TPUs required for good mechanical properties cannot be achieved. In fact, due to the excessively high and fluctuating viscosity of the prepolymer stage, this process is also very unstable and no longer works satisfactorily below 60 Shore A, so that the extruder often stops.

[0007] For example, to improve the low-temperature impact strength of polyester-based TPUs for ski boot applications, polyether polyols with a molecular weight greater than 1600 g / mol, such as polytetramethylene ether glycol (US4980445A) and polypropylene glycol ethers (WO / 2018 / 158327), are used as modifiers. Since the hard and soft phases in TPU are incompatible, resulting in poor coupling of these phases, it is difficult to incorporate such polyethers as pure soft phases into TPUs with a hardness of more than 60 Shore D. Without a modifier, it is difficult to prepare a hard TPU with good low-temperature impact strength.

[0008] The use of polypropylene glycol or poly(propylene oxide) homopolymers (hereinafter also referred to as C3 polyether homopolymer polyols) as polyol components in the preparation of thermoplastic polyurethanes is particularly interesting due to the low costs as starting materials. For example, WO 2020 / 109566 A1 discloses the use of polypropylene glycol in the preparation of thermoplastic polyurethanes, wherein polyols based on polypropylene glycol are reacted with polyisocyanates.

[0009] However, the use of polypropylene glycol as polyol component has the disadvantage that only thermoplastic polyurethanes with relatively low Shore A or theoretical hardness can be synthesized with adequate mechanical properties and abrasion resistance. Rigid thermoplastic polyurethanes based on polypropylene glycol generally exhibit these typical properties only to a small extent or not at all and are therefore not suitable for applications requiring significantly harder materials. In addition, thermoplastic polyurethanes of this type exhibit low low-temperature impact strength and are therefore no longer considered for use in articles that are also exposed to low temperatures.

[0010] Problem that the invention aims to solve

[0011] The problem to be solved by the present invention is therefore to provide a process for preparing polyether-containing thermoplastic polyurethanes having improved mechanical properties, in particular having increased hardness or increased tensile strength and / or low-temperature impact strength. In particular, a process for the cost-effective preparation of polyether-containing thermoplastic polyurethanes having improved mechanical properties, in particular having increased hardness or increased tensile strength and / or low-temperature impact strength, should be provided. 2 Method for preparing balanced polyether-containing thermoplastic polyurethanes.

[0012] Solution to the problem

[0013] The problem is solved by a process for preparing a polyether-containing thermoplastic polyurethane by reacting a composition comprising or consisting of:

[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 agent and / or additive,

[0019] Features

[0020] The polyether homopolymer polyol is a C3 polyether homopolymer polyol (A1), and component (A) further contains at least one component (A2), wherein the component (A2) comprises or consists 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 components (A1) to (A2) is 95:5 to 25:75, based on the total mass of components (A1) and (A2).

[0021] The invention further relates to polyether-containing thermoplastic polyurethanes obtained or obtainable by the process according to the invention.

[0022] The invention also relates to the use of the polyether-containing thermoplastic polyurethanes according to the invention for producing injection-molded articles; extruded articles; pressed articles; compression-molded articles; 3D-printed articles; articles for mechanical engineering, road construction and railway construction; medical and dental articles, in particular orthodontic appliances for treating tooth malalignments; shoes, in particular ski boots; articles for the automotive industry; articles for the electrical industry, in particular cable sheaths, housings and plugs; consumer goods; coatings; hoses; profiles; belts; films; fibers; nonwovens; textiles; damping elements; sealing materials.

[0023] The present invention furthermore 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.

[0024] Finally, the present invention relates to the use of C3 polyether homopolymer polyols in combination with C2 polyether homopolymer polyols and / or C2 / C3 polyether block copolymer polyols and / or C4 polyether homopolymer polyols for increasing the Charpy impact strength and / or tensile strength of polyether-containing thermoplastic polyurethanes, in particular the polyether-containing thermoplastic polyurethanes according to the invention, wherein the low-temperature impact strength is determined in particular as the Charpy impact strength.

[0025] Surprisingly, it has been found that when the polyether homopolymer polyol used in the preparation of polyether-containing thermoplastic polyurethanes is a C3 polyether homopolymer polyol, the mechanical properties of these polyurethanes, in particular the hardness or tensile strength and / or low-temperature impact strength, can be improved by additionally using, in addition to the C3 polyether homopolymer polyol, a C2 polyether homopolymer polyol and / or a C2 / C3 polyether block copolymer polyol and / or a C4 polyether homopolymer polyol.

[0026] In the context of the present invention, C2 polyether homopolymer polyols are understood to be polyols based on polyethylene glycol or poly(ethylene oxide), C3 polyether homopolymer polyols are understood to be polyols based on polypropylene glycol or poly(propylene oxide), C2 / C3 polyether block copolymer polyols are understood to be polyols based on polyethylene glycol or (polyethylene oxide) and polypropylene glycol or (polypropylene oxide), and C4 polyether homopolymer polyols are understood to be polyols based on polytetramethylene glycol. "C" in "C2", "C3", etc., stands for a carbon atom, wherein the number following it indicates the number of carbon atoms in the repeating unit / repeat unit of the respective polymer.

[0027] It is particularly preferred that the polyether homopolymer polyol is a C3 polyether homopolymer polyol (A1).

[0028] The process of the invention can be carried out discontinuously or continuously, wherein the continuous process variant, especially on an industrial scale (e.g. as an online one-step process), is preferred. In addition, the process is also preferably carried out without solvent. Other possible synthesis processes are, for example, the so-called prepolymer process, MDI splitting or the 3-stage equivalent prepolymer process, but these processes are generally known to those skilled in the art.

[0029] In the method of the present invention, it is preferred that

[0030] ■ The number average molecular weight of the C2 polyether homopolymer polyol is 500 to 4000 g / mol, preferably 1000 to 3000 g / mol;

[0031] ■ The number average molecular weight of the C3 polyether homopolymer polyol is 500 to 8000 g / mol, preferably 1000 to 4500 g / mol;

[0032] ■ the number average molecular weight of the C2 / C3 polyether block copolymer polyol is 1000 to 4000 g / mol, preferably 1500 to 2500 g / mol; and / or

[0033] ■ The number average molecular weight of the C4 polyether homopolymer polyol is from 500 to 4500 g / mol, preferably from 1500 to 4500 g / mol.

[0034] In another embodiment of the method of the present invention, the theoretical hardness of the polyether-containing thermoplastic polyurethane is ≥40%, wherein the theoretical hardness is calculated by the following formula:

[0035] Theoretical hardness = (n(chain extender)*M(polyisocyanate)+m(chain extender)) / m 总和

[0036] Where n = molar amount of component, M = molar mass of component, and m = mass of component.

[0037] It is further preferred in the context of the present invention that the molar ratio of ethylene oxide units to propylene oxide units in the C2 / C3 polyether block copolymer polyols is from 95:5 to 5:95, preferably from 80:20 to 20:80, based on the molar amounts of alkylene oxide used in the preparation of the polyether.

[0038] It is further preferred that the mass ratio of components (A1) to (A2) is from 65:35 to 30:70, based on the total mass of components (A1) and (A2).

[0039] It is further preferred that the polyisocyanate of component (B) comprises or consists of diphenylmethane 4,4'-diisocyanate, diphenylmethane 2,4'-diisocyanate, diphenylmethane 2,2'-diisocyanate, hexamethylene 1,6-diisocyanate, toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, isophorone diisocyanate, naphthalene 1,5-diisocyanate, 1,1'-methylenebis(4-isocyanatocyclohexane) or mixtures thereof, preferably diphenylmethane 4,4'-diisocyanate, diphenylmethane 2,4'-diisocyanate, diphenylmethane 2,2'-diisocyanate or mixtures thereof.

[0040] Preferably, the chain extender of component (C) is selected from the group comprising or consisting of ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, 1,4-di(β-hydroxyethyl)hydroquinone, triethylene glycol, tetraethylene glycol or a mixture thereof, preferably ethane-1,2-diol, butane-1,4-diol, hexane-1,6-diol, triethylene glycol or a mixture thereof.

[0041] Catalysts (D) which can be used include the conventionally known catalysts in polyurethane chemistry. Suitable catalysts are conventional tertiary amines known per se, such as triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol, diazabicyclo[2.2.2]octane, etc., and in particular organometallic compounds, such as titanates, iron compounds, bismuth compounds, tin compounds, such as tin diacetate, tin dioctoate, tin dilaurate or dialkyltin salts of aliphatic carboxylic acids, such as dibutyltin diacetate, dibutyltin dilaurate, etc. Preferred catalysts are organometallic compounds, in particular titanates, iron compounds or tin compounds. Very particular preference is given to dibutyltin dilaurate, tin dioctoate and titanates.

[0042] Additives, auxiliaries and additives (E) which 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 and reinforcing agents as well as monofunctional chain terminators. Reinforcing agents are in particular fiber reinforcements, such as inorganic fibers, which are produced according to the prior art and can also be sized. As monofunctional chain terminators, monoalcohols, such as 1-butanol, 1-hexanol, 1-octanol and stearyl alcohol, or monoamines, such as 1-butylamine and stearylamine, can be used to set a specific TPU molecular weight. Further descriptions of the auxiliaries and additives mentioned can be found in the professional literature, for example JH Saunders, KC Frisch: "High Polymers", Volume XVI, Polyurethane, Parts 1 and 2, Interscience Publishers 1962 and 1964, R. H. Müller (editor): Taschenbuch der Kunststoff-Additive, 3rd edition, Hanser Verlag, München 1989, or DE-A 2901774.

[0043] Further preferably, the method comprises or consists of the following steps:

[0044] i) reacting a mixture consisting of the total amount of component (A), a part of the amount of component (B) and optionally a part or the total amount of components (D) and / or (E) to give an NCO-functional prepolymer, wherein the molar ratio of (part of) component (B) to component (A) is from 1.1:1.0 to 5.0:1.0;

[0045] 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 remainder of components (D) and / or (E);

[0046] iii) reacting the OH-functional prepolymer from step ii) with the remaining amount of component (B) and optionally the remaining amount of components (D) and / or (E) to obtain a polyether-containing thermoplastic polyurethane;

[0047] In step ii), the molar ratio of NCO functional groups to OH functional groups in component (C) is preferably less than 1.0.

[0048] The reaction is preferably carried out at an isocyanate index of 0.9 to 1.2, more preferably 0.95 to 1.1, and particularly preferably 0.97 to 1.03. The isocyanate index (also referred to as index, NCO / OH index or isocyanate index) is understood here as the quotient of the molar amount [mol] of the isocyanate groups actually used and the molar amount [mol] of the isocyanate-reactive groups actually used. In other words, the index represents the percentage of the amount of isocyanate actually used to the stoichiometric amount of isocyanate (i.e. the amount calculated for OH equivalent conversion). The equivalents of NCO groups and NCO-reactive hydrogen atoms correspond to an NCO / OH index of 1 here. The isocyanate index is calculated here by the following formula:

[0049] Index = [(number of moles of isocyanate groups) / (number of moles of isocyanate-reactive groups)]

[0050] The polyether-containing thermoplastic polyurethane according to the invention preferably has

[0051] ■ a tensile strength of at least 17 MPa, preferably at least 22 to 60 MPa, measured according to ISO 53504 (2009-10); and / or

[0052] ■At least 30KJ / m measured at -20℃ according to DIN EN ISO179 / 1eA(2010) 2 , preferably 50 to 140 KJ / m 2 Charpy impact strength.

[0053] In the context of the present invention, the Charpy impact strength measured at -20°C according to DIN EN ISO 179 / 1eA (2010) is understood to be a measure of low temperature impact strength. The Charpy impact strength test was carried out on injection molded samples at -20°C according to DIN EN ISO 179 / 1eA (2010). The test samples had the following dimensions: length 80±2m, width 10.0±0.2mm and thickness 4.0±0.2mm. The test samples were notched. The notch bottom radius rN was 0.25±0.05mm.

[0054] Implementation plan:

[0055] The present invention particularly relates to the following embodiments:

[0056] In a first embodiment, the present invention is directed to a process for preparing a polyether-containing thermoplastic polyurethane by reacting a composition comprising or consisting of:

[0057] (A) at least one polyether homopolymer polyol,

[0058] (B) at least one polyisocyanate,

[0059] (C) at least one chain extender,

[0060] (D) optionally a catalyst,

[0061] (E) optionally at least one additive, auxiliary agent and / or additive,

[0062] Features

[0063] The polyether homopolymer polyol is a C3 polyether homopolymer polyol (A1), and component (A) further contains at least one component (A2), wherein the component (A2) comprises or consists 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 components (A1) to (A2) is 95:5 to 25:75, based on the total mass of components (A1) and (A2).

[0064] In a second embodiment, the invention relates to a method according to embodiment 1, characterized in that

[0065] ■ The number average molecular weight of the C2 polyether homopolymer polyol is 500 to 4000 g / mol, preferably 1000 to 3000 g / mol;

[0066] ■ The number average molecular weight of the C3 polyether homopolymer polyol is 500 to 8000 g / mol, preferably 1000 to 4500 g / mol;

[0067] ■ the number average molecular weight of the C2 / C3 polyether block copolymer polyol is 1000 to 4000 g / mol, preferably 1500 to 2500 g / mol; and / or

[0068] ■ The number average molecular weight of the C4 polyether homopolymer polyol is from 500 to 4500 g / mol, preferably from 1500 to 4500 g / mol.

[0069] In a third embodiment, the invention relates to a method 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 by the following formula:

[0070] Theoretical hardness = (n(chain extender)*M(polyisocyanate)+m(chain extender)) / m 总和

[0071] Where n = molar amount of component, M = molar mass of component, and m = mass of component.

[0072] In a fourth embodiment, the present invention relates to a process according to any of the preceding embodiments, characterized in that the molar ratio of ethylene oxide units to propylene oxide units in the C2 / C3 polyether block copolymer polyol is from 95:5 to 5:95, preferably from 80:20 to 20:80, based on the molar amount of alkylene oxide used in the preparation of the polyether.

[0073] In a fifth embodiment, the present invention relates to a method according to any of the preceding embodiments, characterized in that the mass ratio of components (A1) to (A2) is from 65:35 to 30:70, based on the total mass of components (A1) and (A2).

[0074] In a sixth embodiment, the invention relates to a process according to any of the preceding embodiments, characterized in that the polyisocyanate of component (B) comprises or consists of diphenylmethane 4,4′-diisocyanate, diphenylmethane 2,4′-diisocyanate, diphenylmethane 2,2′-diisocyanate, hexamethylene 1,6-diisocyanate, toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, isophorone diisocyanate, naphthalene 1,5-diisocyanate, 1,1′-methylenebis(4-isocyanatocyclohexane) or mixtures thereof, preferably diphenylmethane 4,4′-diisocyanate, diphenylmethane 2,4′-diisocyanate, diphenylmethane 2,2′-diisocyanate or mixtures thereof.

[0075] In a seventh embodiment, the present invention relates to a method according to any of the preceding embodiments, characterized in that the chain extender of component (C) is selected from the group comprising or consisting of ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, 1,4-di(β-hydroxyethyl)hydroquinone, triethylene glycol, tetraethylene glycol or mixtures thereof, preferably ethane-1,2-diol, butane-1,4-diol, hexane-1,6-diol, triethylene glycol or mixtures thereof.

[0076] In an eighth embodiment, the present invention relates to a method according to any of the preceding embodiments, characterized in that the additives, auxiliaries and / or additions of component (E) are 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.

[0077] In a ninth embodiment, the invention relates to a method according to any one of the preceding embodiments, characterized in that the method comprises or consists of the following steps:

[0078] i) reacting a mixture consisting of the total amount of component (A), a part of the amount of component (B) and optionally a part or the total amount of components (D) and / or (E) to give an NCO-functional prepolymer, wherein the molar ratio of (part of) component (B) to component (A) is from 1.1:1.0 to 5.0:1.0;

[0079] 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 remainder of components (D) and / or (E);

[0080] iii) reacting the OH-functional prepolymer from step ii) with the remaining amount of component (B) and optionally the remaining amount of components (D) and / or (E) to obtain a polyether-containing thermoplastic polyurethane;

[0081] In step ii), the molar ratio of NCO functional groups to OH functional groups in component (C) is preferably less than 1.0.

[0082] In a tenth embodiment, the invention relates to a process according to any of the preceding embodiments, characterized in that the reaction is carried out at an isocyanate index of 0.9 to 1.2, preferably 0.95 to 1.1, more preferably 0.97 to 1.03.

[0083] In an eleventh embodiment, the present invention relates to a polyether-containing thermoplastic polyurethane obtained or obtainable by a process according to any one of embodiments 1 to 10.

[0084] In a twelfth embodiment, the invention relates to a polyether-containing thermoplastic polyurethane according to embodiment 11, characterized in that the polyether-containing thermoplastic polyurethane has

[0085] ■ a tensile strength of at least 17 MPa, preferably at least 22 to 60 MPa, measured according to ISO 53504 (2009-10); and / or

[0086] ■At least 30KJ / m measured at -20℃ according to DIN EN ISO179 / 1eA(2010) 2 , preferably 50 to 140 KJ / m 2 Charpy impact strength.

[0087] In a thirteenth embodiment, the present invention relates to the use of the polyether-containing thermoplastic polyurethane according to embodiment 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 construction and railway construction; medical and dental articles, in particular orthodontic appliances for treating tooth malalignment; shoes, in particular ski boots; articles for the automotive industry; articles for the electrical industry, in particular cable sheaths, housings and plugs; consumer goods; coatings; hoses; profiles; belts; films; fibers; nonwovens; textiles; damping elements; sealing materials.

[0088] In a fourteenth embodiment, the present invention is directed to an article comprising or consisting of the polyether-containing thermoplastic polyurethane according to embodiment 11 or 12, wherein the article is preferably a ski boot.

[0089] In a fifteenth embodiment, the present 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 tensile strength of a polyether-containing thermoplastic polyurethane, especially a polyether-containing thermoplastic polyurethane according to embodiment 11 or 12, wherein the low-temperature impact strength is particularly determined as the Charpy impact strength.

[0090] Embodiment and comparative example:

[0091] The present invention is further described below by way of examples, but the present invention is not limited thereto.

[0092] Components used :

[0093] ■ Polyol 1 = polypropylene glycol (C3 polyether homopolymer polyol), initiator propylene glycol (poly(propylene oxide) homopolymer); OH value about 56: secondary terminal OH group ratio: >90%;

[0094] ■Polyol 2= 2000 (commercial product from Invista: polytetramethylene glycol; OH value about 56), (C4 polyether homopolymer polyol);

[0095] ■ Polyol 3 = poly(propylene oxide)-poly(ethylene oxide) block copolymer (C2 / C3 polyether block copolymer polyol): propylene glycol (initiator) with polymerized alkylene oxide (molar ratio of ethylene oxide units to propylene oxide units of about 51:49); OH value of about 56, primary terminal OH group ratio: >90%), KOH catalyzed

[0096] ■ Polyol 4 = polypropylene glycol (C3 polyether homopolymer polyol), starting propylene glycol (poly(propylene oxide) homopolymer), OH value about 28: secondary terminal OH group ratio: >90%)

[0097] ■ BDO = butane-1,4-diol (BDO, purity ≥ 99 wt %), from Ashland.

[0098] ■TEG = triethylene glycol (TEG, purity ≥ 95 wt. %) from Thermo Fischer (Kandel) GmbH.

[0099] ■ MDI = diphenylmethane 4,4'-diisocyanate (MDI, purity ≥ 99 wt. %) from Covestro AG.

[0100] Measurement method used:

[0101] ■OH value titrated according to DIN 53240-2:2007-11

[0102] ■Tensile test: measured according to ISO 53504 (2009-10) at a tensile speed of 200 mm / min;

[0103] ■Charpy impact strength test (low temperature impact strength): Charpy impact strength test was performed on injection molded samples at -20°C according to DIN EN ISO179 / 1eA (2010). The dimensions of the test sample were as follows: length 80±2mm, width 10.0±0.2mm, thickness 4.0±0.2mm. The test sample had a notch. The notch bottom radius rN was 0.25±0.05mm.

[0104] For example :

[0105] Table 1 illustrates the present invention through several examples. The preparation methods used are as follows.

[0106] Preparation (discontinuous process):

[0107] Stage 1: Partial amount 1 (see Table 1) of MDI is reacted at about 140° C. with 1 mol of a polyol or a polyol mixture with stirring to a conversion of >90 mol %, based on the polyol.

[0108] Stage 2: The chain extender was added to the stirred reaction mixture and stirred vigorously for about 10 seconds.

[0109] Stage 3: Part 2 (see Table 1) of MDI was added to the stirred reaction mixture. The reaction mixture was stirred for a further 20 seconds and then poured onto a metal plate and heat treated at 120° C. for 30 minutes.

[0110] The obtained TPU casting plate was chopped and granulated. The pellets were processed 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 to obtain rods (mold temperature: 40°C; rod size: 80x 10x 4mm) or plates (mold temperature: 70°C; size: 125x 50x 2mm).

[0111] The mechanical values ​​(tensile strength and tensile elongation) and Charpy low-temperature impact strength of the prepared TPU products were measured.

[0112] Examples 1 to 18 describe a discontinuous process.

[0113] Preparation (continuous process, e.g. reactive extruder):

[0114] Similar to the discontinuous experiment, TPU can also be prepared discontinuously, for example using a twin-screw reaction extruder (but the preparation is not limited to this form of preparation, see "belt method").

[0115] Part 1 of the MDI preheated to 60° C. is metered into a tube equipped with a pin mixer using a gear pump. The polyol or polyol mixture heated to 140° C. is pumped into the same tube using a second gear pump. The length / diameter ratio of the tube is 8:1. The reaction mixture flows continuously into a connected twin-screw extruder, which is heated externally to 140° C. to 220° C. The chain extender and part 2 of the MDI are added in the middle of the screw. The speed of the screw shaft is 300 rpm. At the end of the screw, the hot melt is pelletized and cooled. The pellets are processed by injection molding to give test specimens, on which the properties listed in the table are measured.

[0116] Example 19 describes a continuous process (extruder process).

[0117] Table 1:

[0118]

[0119]

[0120] *Comparative example not of the present invention; **Cannot be processed;

[0121] # Theoretical hardness (= theoretical hardness or TH) is the weight ratio of the hard segments in the TPU: TH = (n(KV)*M(ISO)+m(KV)) / m 全部 , where KV = chain extender, ISO = isocyanate (here MDI)

[0122] - Comparative Examples 1 and 18 are TPU formulations based on polypropylene glycol (C3 polyether homopolymer polyol), TPUs which cannot be prepared and / or cannot be processed by injection molding.

[0123] - Comparative Examples 3 and 5-7 are based on polypropylene glycol-polyethylene glycol (C2 / C3 polyether block copolymer polyol) formulations, producing TPUs with good tear strength but poor low temperature impact strength.

[0124] - Examples 4, 8-13 and 15-17 show TPU formulations with C2 / C3 polyether block copolymer polyols blended with C3 polyether homopolymer polyols that have good tear strength and good low temperature impact strength (Charpy impact strength).

[0125] - Comparative Example 14 shows a TPU formulation based on a C2 / C3 polyether block copolymer polyol mixed with polypropylene glycol (C3 polyether homopolymer polyol) in a ratio of about 80:20; this material exhibits good tear strength, but unsatisfactory low temperature impact strength.

[0126] - Example 2 shows a TPU formulation based on C3 ether polyols and C4 polyether homopolymer polyols (could also be polyTHF or PTMEG) with good mechanical properties and good low temperature impact strength.

[0127] Example 19 shows that the process according to the invention also leads to the preparation of polyether-containing thermoplastic polyurethanes having good tear strength and at the same time good low-temperature impact strength in the continuous process variant.

Claims

1. A process for preparing a polyether-containing thermoplastic polyurethane by reacting a composition comprising or consisting of: (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 agent and / or additive, Features The polyether homopolymer polyol is a C3 polyether homopolymer polyol (A1), and component (A) further contains at least one component (A2), wherein the component (A2) comprises or consists 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 components (A1) to (A2) is 95:5 to 25:75, based on the total mass of components (A1) and (A2).

2. The method according to claim 1, characterized in that ■ The number average molecular weight of the C2 polyether homopolymer polyol is 500 to 4000 g / mol, preferably 1000 to 3000 g / mol; ■ The number average molecular weight of the C3 polyether homopolymer polyol is 500 to 8000 g / mol, preferably 1000 to 4500 g / mol; ■ the number average molecular weight of the C2 / C3 polyether block copolymer polyol is 1000 to 4000 g / mol, preferably 1500 to 2500 g / mol; and / or ■ The number average molecular weight of the C4 polyether homopolymer polyol is from 500 to 4500 g / mol, preferably from 1500 to 4500 g / mol.

3. The method according to claim 1 or 2, characterized in that: The theoretical hardness of the thermoplastic polyurethane containing polyether is ≥40%, wherein the theoretical hardness is calculated by the following formula: Theoretical hardness = (n(chain extender)*M(polyisocyanate)+m(chain extender)) / m 总和 Where n = molar amount of component, M = molar mass of component, and m = mass of component.

4. The method according to any one of the preceding claims, characterized in that The molar ratio of ethylene oxide units to propylene oxide units in the C2 / C3 polyether block copolymer polyol is from 95:5 to 5:95, preferably from 80:20 to 20:80, based on the molar amount of alkylene oxide used in the preparation of the polyether.

5. The method according to any one of the preceding claims, characterized in that The mass ratio of components (A1) to (A2) is 65:35 to 30:70, based on the total mass of components (A1) and (A2).

6. The method according to any one of the preceding claims, characterized in that The polyisocyanate of component (B) comprises or consists of diphenylmethane 4,4'-diisocyanate, diphenylmethane 2,4'-diisocyanate, diphenylmethane 2,2'-diisocyanate, hexamethylene 1,6-diisocyanate, toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, isophorone diisocyanate, naphthalene 1,5-diisocyanate, 1,1'-methylenebis(4-isocyanatocyclohexane) or mixtures thereof, preferably diphenylmethane 4,4'-diisocyanate, diphenylmethane 2,4'-diisocyanate, diphenylmethane 2,2'-diisocyanate or mixtures thereof.

7. The method according to any one of the preceding claims, characterized in that The chain extender of component (C) is selected from the group comprising or consisting of ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, 1,4-di(β-hydroxyethyl)hydroquinone, triethylene glycol, tetraethylene glycol or a mixture thereof, preferably ethane-1,2-diol, butane-1,4-diol, hexane-1,6-diol, triethylene glycol or a mixture thereof.

8. The method according to any one of the preceding claims, characterized in that The additives, auxiliaries and / or additives of component (E) are 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.

9. The method according to any one of the preceding claims, characterized in that The method comprises or consists of the following steps: i) reacting a mixture consisting of the total amount of component (A), a part of the amount of component (B) and optionally a part or the total amount of components (D) and / or (E) to give an NCO-functional prepolymer, wherein the molar ratio of (part of) component (B) to component (A) is 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 remainder of components (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 components (D) and / or (E) to obtain a polyether-containing thermoplastic polyurethane; In step ii), the molar ratio of NCO functional groups to OH functional groups in component (C) is preferably less than 1.

0.

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

03.

11. A polyether-containing thermoplastic polyurethane obtained or obtainable according to the process of any one of claims 1 to 10.

12. The polyether-containing thermoplastic polyurethane according to claim 11, characterized in that The polyether-containing thermoplastic polyurethane has ■ a tensile strength of at least 17 MPa, preferably at least 22 to 60 MPa, measured according to ISO 53504 (2009-10); and / or ■At least 30KJ / m measured at -20℃ according to DIN EN ISO179 / 1eA(2010) 2 , preferably 50 to 140 KJ / m 2 Charpy impact strength.

13. Use of the polyether-containing thermoplastic polyurethane according to claim 11 or 12 for producing injection-molded articles; extruded articles; pressed articles; compression-molded articles; 3D-printed articles; articles for mechanical engineering, road construction and railway construction; medical and dental articles, in particular orthodontic appliances for treating tooth malpositions; shoes, in particular ski boots; articles for the automotive industry; articles for the electrical industry, in particular cable sheaths, housings and plugs; consumer goods; coatings; hoses; profiles; belts; films; fibers; nonwovens; textiles; damping elements; sealing materials.

14. An article comprising or consisting of the 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 tensile strength of a polyether-containing thermoplastic polyurethane, in particular a polyether-containing thermoplastic polyurethane according to claim 11 or 12, wherein the low-temperature impact strength is determined in particular as the Charpy impact strength.

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