High-hardness thermoplastic polyurethane material with glass transition temperature higher than room temperature

Abstract

Disclosed are reactive formulations and methods for forming a thermoplastic polyurethane (TPU) having a glass transition temperature (Tg) above room temperature, preferably a Tg above 40 DEG C, more preferably above 55 DEG C, a flexural modulus in the range of 300 to 15000 MPa (measured according to ISO 178), most preferably 1500 to 2700 MPa, and a tensile strength at break (according to DIN 53504) in the range of 5 to 150 MPa. The present invention relates to a reactive formulation comprising at least one isocyanate composition and an isocyanate reactive composition, the isocyanate reactive composition comprising at least one molecular weight lt; 500 g / mol of an aromatic dicarboxylic acid-based diol chain extender and optionally a filler. Furthermore, a glass transition temperature (Tg) gt; a TPU material having a room temperature and a flexural modulus of 300 to 15000 MPa (measured according to ISO 178), which is thermally renewable, and which is optionally manufactured with a terephthalic acid-based polyester glycol chain extender made from regenerated PET.

Description

Technical Field

[0001] The present invention relates to reactive formulations and methods for making thermoplastic polyurethane materials that are easy to process, have high hardness and high flexural modulus, and have a glass transition temperature above room temperature.

[0002] Furthermore, the thermoplastic polyurethane material of the present invention has (at least partially) an amorphous structure and can be processed at temperatures below 250°C.

[0003] The thermoplastic polyurethane materials of the present invention can be easily combined with fillers and / or fibers to further enhance the strength and hardness of the thermoplastic polyurethane materials and make them ideally suited for use in composite materials and flooring materials.

[0004] The thermoplastic polyurethane material of the present invention can optionally be made from sustainable products due to the fact that the reactive formulation used to make the thermoplastic polyurethane material can contain recycled starting materials or thermoplastic polyurethane (TPU) materials. In addition, the thermoplastic polyurethane material itself is thermally recyclable. Background Art

[0005] Thermoplastic polyurethane (TPU) materials with high hardness and high flexural modulus in the prior art are TPU materials with a high content of low molecular weight compounds (high hard block content). Due to the high crystallinity and / or hydrogen bond density of these TPU materials, the processing temperature is usually very close to the degradation temperature of the thermoplastic polyurethane material.

[0006] One material that solves the problem of narrow processing windows is Isoplast ® Materials, such as the reference material Isoplast ®301 (high hard block TPU from Lubrizol), as described in US5167899 and US5574092A. The mechanism behind it is explained in US5574092A, that is, depolymerization is carried out using aromatic diols at processing temperatures (the term aromatic diol used in US5574092A specifically describes an aromatic or heteroaromatic structure having two OH groups directly connected to aromatic carbon atoms, which produces a thermally reversible urethane bond when reacted with isocyanate). A hard, extrudable polyurethane material is disclosed, which has a specific amount of hard segments and has excellent microfiber forming properties such as low viscosity, high melt strength and good melt elasticity when depolymerized at melt temperatures. The depolymerized polyurethane can be easily repolymerized to provide a hard polyurethane with sufficient molecular weight and desired physicochemical properties such as toughness, chemical resistance and dimensional stability. The disadvantage of this "high degree of depolymerization" is that the polyurethane needs to be processed carefully and dried very thoroughly to avoid side reactions (water + isocyanate => CO2 formation) that cause bubbles in the processed parts (bubbles are weak points in the final part). Extreme drying of the polymer (TPU) and additives (e.g. plasticizers) and / or fillers (such as fibers or powders) using a depolymerization scheme (as described in US5574092A) results in undesirable additional costs and energy consumption.

[0007] The disadvantage of using 90-100 wt% hard block materials (made using conventional chain extenders as isocyanate reactive compounds) rather than the "depolymerization mechanism" as described in US5574092A is that they all show relatively high melting points, especially for monoethylene glycol (MEG) and butanediol (BDO). This means that the materials can only be thermoplastic processed above the melting temperature (>220-230°C). The degradation temperature of these TPUs is often close to or below the melting temperature. This leads to degradation of the polymer during hot processing (especially if long exposure to temperature is required). The processing of these types of TPUs is usually limited to solvent casting to avoid high temperature exposure. Solvent casting not only introduces environmental, health and safety risks (depending on the type of solvent), but also leads to additional energy consumption required to evaporate the solvent.

[0008] In more conventional high hardness TPUs, a sufficient amount of high molecular weight polyols is used in combination with low molecular weight isocyanates and low molecular weight diols (chain extenders) to prepare TPU materials with hard blocks <70 wt%. These high molecular weight polyols are generally more thermally stable (per se) than the low molecular weight hard block phase, resulting in a higher overall thermal stability of the TPU material. However, the flexural modulus of these materials is still low, which makes them unsuitable for many applications. In addition, the use of high molecular weight polyols generally produces TPUs with glass transition temperatures below room temperature, which exhibit undesirable changes in flexural modulus (cold hardening) at lower temperatures. In the specific case where the high molecular weight polyol used is a polyester, the high content of ester bonds makes the material more susceptible to hydrolytic degradation.

[0009] Furthermore, the industry is driven to use less petroleum-based resources and therefore promotes the use of renewable resources and / or the production of renewable materials. More specifically, for thermoplastic polyurethane (TPU) materials, this may mean that the starting materials from which these thermoplastic polyurethane (TPU) materials are made are made from recycled materials and / or the thermoplastic polyurethane (TPU) materials themselves are at least thermally regenerable and do not degrade significantly during processing.

[0010] In order to solve the above problems, it is necessary to produce thermoplastic polyurethane (TPU) materials with high hardness and high flexural modulus, which have good thermal stability and high degradation temperature. Ideally, these thermoplastic polyurethane (TPU) materials are also thermally regenerable without significant loss of properties and are processable at temperatures below 250°C.

[0011] Purpose of the Invention

[0012] The goal was to obtain a thermoplastic polyurethane (TPU) material with high hardness (>50 Shore D, DIN ISO 7619-2) and high flexural modulus (>300 MPa, measured according to ISO 178) at room temperature, good thermal stability and a high degradation temperature (temperature at 5 wt. % loss measured under air conditions according to ISO 11358-1) of >250°C.

[0013] Another object is to produce thermoplastic polyurethane (TPU) materials processable at temperatures below 250°C while providing materials with a glass transition temperature (Tg) above room temperature, preferably a Tg above 40°C, more preferably a Tg above 55°C.

[0014] Another object was to produce thermoplastic polyurethane (TPU) materials which are thermally regenerable and / or melt reprocessable after service life with minimal degradation (as would be expected from the good thermal stability).

[0015] A further object was to develop reactive formulations which are suitable for producing the thermoplastic polyurethane (TPU) materials according to the invention.

[0016] Definitions and terminology

[0017] In the context of the present invention, the following terms have the following meanings:

[0018] 1) The "NCO value" or "isocyanate value" referred to herein is the weight percentage of reactive isocyanate (NCO) groups in an isocyanate, modified isocyanate or isocyanate prepolymer compound.

[0019] 2) As used herein, for the purpose of calculating the isocyanate index, the expression "isocyanate-reactive hydrogen atoms" refers to the sum of the active hydrogen atoms in the hydroxyl and amine groups present in the reactive composition, which means that for the purpose of calculating the isocyanate index during the actual polymerization process, one hydroxyl group is considered to contain one reactive hydrogen, one primary amine group is considered to contain one reactive hydrogen, and one water molecule is considered to contain two reactive hydrogens.

[0020] 3) As referred to herein, the "isocyanate index" or "NCO index" or "index" is the ratio of the available NCO equivalents in a reactive mixture to the sum of the available equivalents of isocyanate-reactive hydrogen atoms present in the reactive mixture, given as a percentage:

[0021] [NCO] x100 (%)

[0022] [Active hydrogen]

[0023] In other words, the NCO index expresses the percentage of isocyanate actually used in the preparation (reactive mixture) relative to the amount of isocyanate theoretically required to react with the amount of isocyanate-reactive hydrogen used in the preparation (reactive mixture). In the specific case where isocyanate prepolymers are used in the reactive mixture, it is obvious that a portion of the NCO equivalents and isocyanate-reactive hydrogen atom equivalents are no longer available for participation in the reaction. Therefore, in the calculation of the isocyanate index, these "consumed" equivalents used to produce the isocyanate prepolymers should not be taken into account.

[0024] 4) The term "average nominal functionality of a compound" (or simply "functionality") is used herein to refer to the number average of functional groups per molecule in a composition. It reflects the true and practical / analytically measurable number average functionality of a chemical structure. In the case of "average nominal hydroxyl functionality" (or simply "hydroxyl functionality"), it is used to refer to the number average hydroxyl functionality (number of hydroxyl groups per molecule) of a polyol or polyol composition, assuming that it is the true and practical / analytically measurable number average functionality. In some cases, this functionality is lower than the theoretically determined functionality (number of active hydrogen atoms per molecule) of the initiators sometimes used in their preparation.

[0025] 5) The term "average nominal functionality of the composition" (or simply "functionality of the composition") is used herein to denote the number average of the functional groups per molecule in the composition. It reflects the true and actual / analytically measurable number average functionality of the composition. In the case of a material blend (isocyanate blend, polyol blend, reactive mixture), the "average nominal functionality" of the blend is equivalent to the "molecular number average functionality" calculated by the total number of molecules in the blend in the denominator. Therefore, it is necessary to use the true and actual / analytically measurable number average functionality of each compound of the blend. In the case of reactive foam formulations, the molecular number average functionality of the entire reactive composition should be considered (thus including all isocyanate compounds and isocyanate-reactive compounds).

[0026] 6) The term "hard block" refers to the ratio of the amount of polyisocyanate + isocyanate-reactive compounds with a molecular weight of less than 500 g / mol (wherein isocyanate-reactive compounds with a molecular weight of more than 500 g / mol incorporated into the polyisocyanate are not taken into account) (in pbw) to the amount of all polyisocyanates + all isocyanate-reactive compounds used (in pbw), multiplied by 100. The hard block content is expressed in % by weight.

[0027] 7) Unless otherwise indicated, the word "average" refers to mean.

[0028] 8) As used herein, the term "thermoplastic" is used in its broadest sense to refer to materials that are reprocessable at elevated temperatures, while "thermoset" refers to materials that exhibit high temperature stability but lack such reprocessability at elevated temperatures. Thermosets typically degrade before melting, which makes them virtually non-reprocessable at melting temperatures.

[0029] 9) As used herein, the term "difunctional" means an average nominal functionality of about 2. Difunctional polyols (also referred to as diols) refer to polyols having an average nominal hydroxyl functionality of about 2 (including values ​​of 1.9 to 2.1). Difunctional isocyanates refer to isocyanate compositions having an average nominal isocyanate functionality of about 2 (including values ​​of 1.9 to 2.1).

[0030] 10) As used herein, the term "polyurethane" is not limited to those polymers that include only urethane bonds or polyurethane bonds. It is well understood by those skilled in the art of preparing polyurethanes that polyurethane polymers may also include allophanates, carbodiimides, urea butadiene diones, and other bonds in addition to urethane bonds.

[0031] 11) The expressions "reaction system", "reactive formulation" and "reactive mixture" are used interchangeably herein and all refer to the combination of reactive compounds used to make the thermoplastic material according to the present invention, wherein the polyisocyanate compound is usually kept in one or more containers separate from the isocyanate-reactive compounds prior to reaction.

[0032] 12) The term "room temperature" refers to a temperature of about 20°C, which means a temperature in the range of 18°C ​​to 25°C. Such temperatures would include 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C and 25°C.

[0033] 13) Unless otherwise indicated, the "weight percent" (expressed as % by weight or wt %) of a component in a composition refers to the weight of the component relative to the total weight of the composition in which it is present, and is expressed as a percentage.

[0034] 14) Unless otherwise indicated, "parts by weight" (pbw) of a component in a composition refers to the weight of that component relative to the total weight of the composition in which it is present, and is expressed as pbw.

[0035] 15) Unless otherwise specified, “Shore A hardness” and “Shore D hardness” refer to the hardness of the material measured according to DIN ISO 7619-1 and DIN ISO 7619-2 respectively.

[0036] 16) "Storage modulus" is measured using dynamic mechanical thermal analysis (DMTA) according to ISO6721 using a double cantilever (flexure mode). It is mainly used to study the flexural behavior of the TPU material according to the present invention as a function of temperature (or as a function of time at certain temperatures). The method is carried out using a heating / cooling rate of 3°C / min at a frequency of 1 Hz and an amplitude of 10 μm. The storage modulus is expressed in MPa.

[0037] 17) "Flexural modulus" or "flexural modulus" is measured according to ISO 178 and is used to study the flexural behavior of the TPU material according to the present invention and is performed using a three-point bending test with a 65 mm support span. The flexural modulus is expressed in MPa.

[0038] 18) The "flexural strength at maximum load" and "flexural strain at maximum load" mentioned herein are measured according to ISO 178 using a support span of 65 mm and are expressed in MPa and %, respectively. These properties describe the maximum load and strain that a sample can withstand in a three-point bending test before it yields or breaks.

[0039] 19) The "tensile strength" and "elongation" mentioned herein are measured according to DIN53504 and are expressed in MPa and %, respectively. The test was carried out using SI sample type and a test speed of 100 mm / min. The tensile strength is expressed in MPa, while the elongation is expressed in %.

[0040] 20) The “glass transition temperature” and “Tg” mentioned in this article refer to the temperature at which a reversible transition from a hard glass state to a rubber elastic state occurs, and is measured according to ISO11357-2:2020 using differential scanning calorimetry at a heating rate of 10 K / min, and the second heating cycle is analyzed.

[0041] 21) "Melt volume rate" and "MVR" are the rate at which a molten resin is extruded through a capillary of specified length and diameter under specified conditions of temperature and pressure, measured as the volume extruded in a specified time. MVR is measured in cubic centimeters per 10 minutes (cm 3 The temperature and load mass (e.g. 8.7 kg) used during the measurement of each sample should be specified.

[0042] 22) The "melting temperature", "melting temperature range", "melting point" and "Tm" mentioned herein are measured using melt volume rate, because most materials according to the present invention are (partially) amorphous. The melting temperature is generally the temperature range caused by the gradual softening and flow of the material. Therefore, it cannot be (easily) determined using differential scanning calorimetry (ISO11357-2:2020). Alternatively, the melting temperature of the material according to the present invention is taken as the melting temperature of the material according to the present invention when using a load mass of 8.7 kg and at an MVR (according to ISO1133, using a preheating time of 5 minutes) ≥ 1 cm 3 / 10min is measured by the temperature.

[0043] 23) The term "difunctional polyol" refers to a polyol having an average hydroxyl functionality of about 2, preferably 1.9-2.1. The difunctional polyol (diol) composition according to the present invention is not allowed to have an average hydroxyl functionality greater than 2.2, and is not allowed to have an average hydroxyl functionality less than 1.8.

[0044] 24) "High molecular weight isocyanate-reactive compounds" and "high MW isocyanate-reactive compounds" herein refer to isocyanate-reactive compounds with a molecular weight > 500 g / mol having isocyanate-reactive functional groups and a functionality of 1.8 to 2.5. Examples are polyols, amines or other isocyanate-reactive compounds with a molecular weight > 500 g / mol. These compounds have at least 1 isocyanate-reactive hydrogen atom.

[0045] 25) "Low molecular weight isocyanate reactive compound" and "low MW isocyanate reactive compound" herein refers to an isocyanate reactive compound having an isocyanate reactive functional group and a functionality of 1.8 to 2.5 with a molecular weight <500 g / mol. Examples are polyols, amines or other isocyanate reactive compounds having a molecular weight <500 g / mol. These compounds have at least 1 isocyanate reactive hydrogen atom. The hydroxyl number and the average nominal functionality can be used to calculate the number average molecular weight of certain blends of isocyanate reactive compounds.

[0046] 26) "Reactive extrusion" refers to a manufacturing process that combines the traditionally separate chemical processes (polymer synthesis and / or modification) and extrusion (melting, blending, structuring, devolatilization, and shaping) into a single process performed on an extruder. Typically, two or more liquid compositions are fed into an extruder where the materials are polymerized while being maintained in the molten phase.

[0047] 27) "Dicarboxylic acids" correspond to organic compounds containing two carboxyl functional groups (-COOH). The general molecular formula of a dicarboxylic acid can be written as HOOC-R-COOH, where R can be aliphatic or aromatic. The most important aromatic dicarboxylic acids are phthalic acid, isophthalic acid and terephthalic acid (ortho-, meta- and para-isomers). Terephthalic acid is used to make polyesters known by brand names such as PET.

[0048] 28) "Dicarboxylic acid-based diols" refer to the reaction products of dicarboxylic acids with other chemicals to form diols. Typically, dicarboxylic acids are combined with diols to form dicarboxylic acid-based diols. When the dicarboxylic acid is an aromatic dicarboxylic acid, an aromatic dicarboxylic acid-based diol is formed. Recycled terephthalic acid from PET can be used as a source of aromatic dicarboxylic acid-based diols in the present invention. In practice, these aromatic dicarboxylic acid-based diols can be very pure products or complex mixtures of diols. In the case of complex mixtures of diols produced during the preparation of aromatic dicarboxylic acid-based diols, the hydroxyl value and average nominal functionality of the mixture can be used to calculate the number average molecular weight. DETAILED DESCRIPTION

[0049] The present invention discloses a thermoplastic polyurethane (TPU) material having a glass transition temperature (Tg) above room temperature and having surprisingly good mechanical properties, such as a high flexural modulus (>300 MPa, measured according to ISO 178) and a high hardness (>50 Shore D, DIN ISO 7619-2) at room temperature. In addition, the TPU material according to the present invention is processable at temperatures below 250°C and is easily melt-reprocessable and recyclable after use.

[0050] The present invention discloses a method and a reactive mixture for producing the TPU material according to the present invention.

[0051] The use of the reactive mixture according to the present invention will produce a completely or at least partially amorphous high hard block TPU material (hard block> 70% by weight), which provides a much wider processing window than the crystalline high hard block TPU material of the prior art. Amorphous TPU will allow easier processing, and ultimately the easier processing allows the formulator to have greater freedom to incorporate fillers (powders, fibers, beads, etc.). Very commonly, for amorphous polymers, the amount of filler that can be incorporated will be higher because it is easier to process. The amorphous nature of the TPU material according to the present invention does not produce a very wide Tg (determined by DSC or DMA), but has a relatively sharp curve. In addition, the storage modulus platform below the glass transition temperature (according to ISO6721, using DMA, using a flexure fixture / mode measurement) remains very constant over a wide temperature range. This produces a good storage modulus retention rate (ISO6721) below the Tg of the material of the present invention. Compared to competing materials such as PVC, for example, it has shown a much faster drop in storage modulus (indicative of softening) below the Tg of the material (measured according to ISO 6721, using DMA, using a flexure fixture / mode).

[0052] The properties of the TPU material according to the invention are achieved by using a reactive formulation having a hard block content of at least 70% by weight and an isocyanate-reactive composition comprising at least a diol chain extender based on an aromatic dicarboxylic acid having a molecular weight of <500 g / mol.

[0053] Thus, the present invention discloses a reactive formulation for forming a thermoplastic polyurethane (TPU) having a Shore D hardness of 50-100 Shore D (measured according to DIN ISO 7619-2) and a glass transition temperature (Tg) > room temperature, the reactive formulation comprising at least:

[0054] - an isocyanate composition comprising at least one difunctional isocyanate compound, and

[0055] an isocyanate-reactive composition comprising an isocyanate-reactive compound selected from at least one diol chain extender based on aromatic dicarboxylic acids having a molecular weight of <500 g / mol, and

[0056] - optionally a catalyst compound, and

[0057] -Optional other additives and / or fillers

[0058] The hard block content of the reactive formulation is >70 wt %, based on the total weight of the isocyanate composition and the isocyanate-reactive composition, the isocyanate index is 75 to 125, and the number average isocyanate functionality and / or the number average hydroxyl functionality is 1.8 to 2.5.

[0059] According to an embodiment, the reactive formulation has a hard block weight % (wt%) > 70 wt%, more preferably > 75 wt%, preferably > 80 wt%, more preferably > 85 wt%, most preferably 90-100 wt%.

[0060] According to embodiments, the isocyanate index of the reactive foam formulation is 75 to 125, 80 to 120, 85 to 120, 88 to 120, 90 to 120, 90 to 110, 92 to 110, 95 to 110, 95 to 105, 95 to 102, 95 to 100.

[0061] According to an embodiment, the number average overall functionality (hydroxyl and NCO functionality) of the reactive formulation (taking into account all isocyanate compounds and isocyanate-reactive compounds) is from 1.8 to 2.2, more preferably from 1.9 to 2.1, more preferably from 1.95 to 2.05, more preferably from 1.95 to 2.02, more preferably from 1.95 to 2.015, more preferably from 1.95 to 2.012, even more preferably from 1.98 to 2.01 and most preferably from 1.98 to 2.005, so that the TPU is thermally regenerable.

[0062] According to an embodiment, the number average functionality of the isocyanate-reactive compound and / or the isocyanate compound and / or the overall reactive formulation (including all isocyanate compounds and isocyanate-reactive compounds) is 1.8 to 2.5, more preferably 1.9-2.2, more preferably 1.95-2.05, more preferably 1.95-2.02, more preferably 1.95-2.015, more preferably 1.95-2.012, even more preferably 1.98-2.01 and most preferably 1.98-2.005.

[0063] Isocyanate reactive compositions

[0064] According to an embodiment, the isocyanate-reactive composition has a number average hydroxyl functionality of 1.8 to 2.4 and comprises at least 10 wt % of an aromatic carboxylic acid based diol chain extender having a molecular weight <500 g / mol, based on the total weight of all chain extenders in the isocyanate-reactive composition.

[0065] According to an embodiment, the isocyanate-reactive composition comprises at least 10 wt. %, more preferably at least 20 wt. %, more preferably at least 40 wt. %, more preferably at least 50 wt. %, more preferably at least 60 wt. %, more preferably at least 70 wt. %, more preferably at least 80 wt. % of a diol based on an aromatic dicarboxylic acid having a molecular weight ≤ 500 g / mol, based on the total weight of all chain extenders in the isocyanate-reactive composition.

[0066] According to an embodiment, the number average molecular weight (calculated from functionality and hydroxyl value, OH value) of the diol chain extender based on aromatic dicarboxylic acid is 45 g / mol to 500 g / mol, more preferably 150 g / mol to 500 g / mol, most preferably 250 g / mol to 500 g / mol.

[0067] According to an embodiment, the hydroxyl value (OH value) of the aromatic dicarboxylic acid-based diol chain extender is 224 to 1000 mg KOH / g, more preferably 224 to 750 mg KOH, more preferably 224 to 600 mg KOH, more preferably 224 to 500 mg KOH, most preferably 224 to 280 mg KOH.

[0068] According to an embodiment, the aromatic dicarboxylic acid based diol chain extender is based on phthalic acid selected from phthalic acid, isophthalic acid and / or terephthalic acid, more preferably the aromatic diol chain extender is based on terephthalic acid, most preferably the aromatic diol chain extender is a terephthalic acid based polyester diol chain extender.

[0069] According to an embodiment, the diol chain extender based on aromatic dicarboxylic acid is made using at least 1 type of diol. More preferably, the diol chain extender based on aromatic dicarboxylic acid is made using at least 2 types of diol. Most preferably, the diol chain extender based on aromatic dicarboxylic acid is made using at least 3 types of diol.

[0070] According to an embodiment, the aromatic dicarboxylic acid based diol chain extender is a terephthalic acid based polyester diol chain extender made from recycled PET.

[0071] According to an embodiment, the isocyanate-reactive composition may comprise an aromatic-based diol and an aliphatic-based diol such that at least 20 wt.-% of the diol, preferably >30 wt.-%, preferably >40 wt.-%, preferably >50 wt.-%, preferably >60 wt.-%, preferably >70 wt.-%, more preferably >75 wt.-% of the diol, based on the total weight of the isocyanate-reactive composition, is selected from diols based on aromatic dicarboxylic acids.

[0072] According to an embodiment, one or more additional aliphatic chain extenders other than the aromatic dicarboxylic acid based diol chain extender are present in the reactive formulation in an amount greater than 1 wt % (>1 wt %), more preferably >2 wt %, more preferably >3 wt %, more preferably >4 wt %, more preferably >5 wt %, more preferably >6 wt %, more preferably >7 wt %, more preferably >8 wt %, more preferably >9 wt %, more preferably >10 wt %, based on the total weight of the reactive formulation.

[0073] According to an embodiment, the aromatic dicarboxylic acid based diol chain extender is made using ≤ 3 different types of dicarboxylic acids, more preferably using ≤ 2 different types of dicarboxylic acids, more preferably using 1 type of dicarboxylic acid, most preferably using only terephthalic acid.

[0074] According to the embodiment, the aromatic dicarboxylic acid used to make the diol chain extender based on aromatic dicarboxylic acids contains at least 50 mol% of terephthalic acid based on the total molar amount of the dicarboxylic acid used. More preferably, the aromatic dicarboxylic acid used to make the diol chain extender based on aromatic dicarboxylic acids contains at least 60 mol% of terephthalic acid based on the total molar amount of the dicarboxylic acid used. More preferably, the aromatic dicarboxylic acid used to make the diol chain extender based on aromatic dicarboxylic acids contains at least 70 mol% of terephthalic acid based on the total molar amount of the dicarboxylic acid used. More preferably, the aromatic dicarboxylic acid used to make the diol chain extender based on aromatic dicarboxylic acids contains at least 80 mol% of terephthalic acid based on the total molar amount of the dicarboxylic acid used. More preferably, the aromatic dicarboxylic acid used to make the diol chain extender based on aromatic dicarboxylic acids contains at least 90 mol% of terephthalic acid based on the total molar amount of the dicarboxylic acid used. More preferably, the aromatic dicarboxylic acid used to make the diol chain extender based on aromatic dicarboxylic acids contains at least 95 mol% of terephthalic acid based on the total molar amount of the dicarboxylic acid used. Most preferably, the aromatic dicarboxylic acid used to make the diol chain extender based on aromatic dicarboxylic acids contains at least only terephthalic acid (100 mol% based on the total molar amount of the dicarboxylic acid used).

[0075] According to an embodiment, the aromatic dicarboxylic acid based diol chain extender is made using ≤ 3 different types of dicarboxylic acids, more preferably using ≤ 2 different types of dicarboxylic acids, more preferably using 1 type of dicarboxylic acid, most preferably using only terephthalic acid.

[0076] According to an embodiment, the Tg (measured according to ISO11357-2:2020) of the diol chain extender based on aromatic dicarboxylic acids is <25°C, more preferably Tg <20°C, more preferably Tg <15°C, more preferably Tg <10°C, more preferably Tg <5°C, more preferably Tg <0°C, more preferably Tg <-5°C, more preferably Tg <-10°C, more preferably Tg <-15°C, more preferably Tg <-20°C, more preferably Tg <-25°C, more preferably Tg <-30°C, more preferably Tg <-35°C. More preferably Tg <-40°C, more preferably Tg <-45°C, most preferably Tg <-50°C.

[0077] According to an embodiment, the terephthalic acid based diol chain extender has a Tg (measured according to ISO 11357-2:2020) <25°C, more preferably Tg <20°C, more preferably Tg <15°C, more preferably Tg <10°C, more preferably Tg <5°C, more preferably Tg <0°C, more preferably Tg <-5°C, more preferably Tg <-10°C, more preferably Tg <-15°C, more preferably Tg <-20°C, more preferably Tg <-25°C, more preferably Tg <-30°C, more preferably Tg <-35°C, more preferably Tg <-40°C, more preferably Tg <-45°C, most preferably Tg <-50°C.

[0078] According to an embodiment, the difference in glass transition temperature (Tg, measured according to ISO 11357-2:2020) between the aromatic dicarboxylic acid-based diol chain extender (Tg CE) and the thermoplastic polyurethane (Tg TPU) is at least 20°C, more preferably at least 30°C, more preferably at least 40°C, more preferably at least 50°C, more preferably at least 60°C, more preferably at least 70°C, more preferably at least 80°C, more preferably at least 90°C, more preferably at least 100°C, more preferably at least 110°C, more preferably at least 115°C, more preferably at least 120°C, more preferably at least 125°C. More preferably at least 130°C, more preferably at least 135°C, more preferably at least 140°C, more preferably at least 145°C, most preferably at least 150°C.

[0079] According to an embodiment, the aromatic dicarboxylic acid-based diol chain extender is a terephthalic acid-based polyester diol chain extender made from recycled PET. The recycled content (including pre-consumer and post-consumer recycled content as defined by ISO 14021) of the terephthalic acid-based polyester diol chain extender made from recycled PET is at least 5% by weight, more preferably ≥10% by weight, more preferably ≥15% by weight, more preferably ≥20% by weight, more preferably ≥25% by weight, more preferably ≥30% by weight, more preferably ≥35% by weight, more preferably ≥40% by weight, more preferably ≥45% by weight, more preferably ≥50% by weight, and most preferably ≥55% by weight, based on the total weight of the isocyanate-reactive composition.

[0080] According to an embodiment, the recycled content (including pre-consumer and post-consumer recycled content as defined by ISO 14021) of the total isocyanate-reactive composition (including both the diol chain extender based on aromatic dicarboxylic acids and possible other isocyanate-reactive components) is at least 2% by weight, more preferably ≥ 5% by weight, more preferably ≥ 10% by weight, more preferably ≥ 15% by weight, more preferably ≥ 18% by weight, more preferably ≥ 20% by weight, more preferably ≥ 22% by weight, more preferably ≥ 24% by weight, more preferably ≥ 26% by weight, more preferably ≥ 28% by weight, more preferably ≥ 30% by weight, more preferably ≥ 32% by weight, more preferably ≥ 34% by weight, more preferably ≥ 36% by weight, more preferably ≥ 38% by weight, most preferably ≥ 40% by weight, based on the total weight of the isocyanate-reactive composition.

[0081] According to an embodiment, the isocyanate-reactive composition comprises ≤50 wt% of high molecular weight polyols having a molecular weight >500 g / mol, more preferably ≤40 wt% of high molecular weight polyols having a molecular weight >500 g / mol, more preferably ≤30 wt% of high molecular weight polyols having a molecular weight >500 g / mol, more preferably ≤20 wt% of high molecular weight polyols having a molecular weight >500 g / mol, more preferably ≤10 wt% of high molecular weight polyols having a molecular weight >500 g / mol, and most preferably the isocyanate-reactive composition contains no high molecular weight polyols.

[0082] According to an embodiment, the isocyanate-reactive composition comprises at least 50% by weight of low molecular weight polyols having a number average molecular weight of ≤500 g / mol, preferably at least 60% by weight of low molecular weight polyols, preferably at least 70% by weight of low molecular weight polyols, preferably at least 80% by weight of low molecular weight polyols, preferably at least 85% by weight of low molecular weight polyols, preferably at least 90% by weight of low molecular weight polyols, preferably at least 95% by weight of low molecular weight polyols, based on the total weight of the isocyanate-reactive composition. Most preferably, the isocyanate-reactive composition contains only low molecular weight diols having a number average molecular weight of ≤500 g / mol.

[0083] According to an embodiment, the isocyanate-reactive compounds in the reactive formulation comprise primarily low MW isocyanate-reactive compounds selected from at least 75 wt% of difunctional polyols, more preferably at least 85 wt% of difunctional polyols, most preferably at least 90 wt% of difunctional polyols, based on the total weight of all isocyanate-reactive compounds in the reactive formulation.

[0084] According to an embodiment, the TPU material according to the present invention may be manufactured using an isocyanate-reactive composition mainly including a low molecular weight diol selected from aromatic dicarboxylic acid-based diols.

[0085] According to an embodiment, the TPU material according to the present invention may be manufactured using an isocyanate-reactive composition mainly including a low molecular weight difunctional polyol selected from an aromatic dicarboxylic acid-based diol and an aliphatic diol-based and / or alicyclic diol-based diol.

[0086] According to an embodiment, the TPU material according to the invention contains a recycled content of ≥2 wt.-%, more preferably ≥5 wt.-%, more preferably ≥10 wt.-%, more preferably ≥15 wt.-%, more preferably ≥20 wt.-%, most preferably ≥25 wt.-%.

[0087] According to an embodiment, the low MW aliphatic-based diol has a molecular weight of <500 g / mol, preferably a molecular weight of 45 g / mol to 500 g / mol, more preferably 50 g / mol to 250 g / mol, and is selected from 1,6-hexanediol, 1,4-butanediol, monoethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,5-pentanediol, polycaprolactone diol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, hydroquinone bis(2-hydroxyethyl) ether (HQEE), 1,3-bis(2-hydroxyethyl)resorcinol (HER), ethanolamine, methyldiethanolamine and / or phenyldiethanolamine and / or a combination of two or more of these chemicals. Preferably the low MW aliphatic based diol is selected from 1,6-hexanediol, 1,4-butanediol, diethylene glycol, 1,4-cyclohexanediol, monoethylene glycol or a combination of two or more of these chemicals.

[0088] According to an embodiment, the molecular weight of the low MW aliphatic diol is 45 g / mol to 500 g / mol, more preferably 45 g / mol to 400 g / mol, more preferably 45 g / mol to 300 g / mol, more preferably 45 g / mol to 250 g / mol, more preferably 60 g / mol to 200 g / mol, most preferably 90 g / mol to 150 g / mol.

[0089] According to an embodiment, the isocyanate-reactive composition may optionally contain a small amount of a high MW isocyanate-reactive compound having a molecular weight>500 g / mol, which is selected from polyester diols, polyether diols and / or polyester polyether diols (including specialty polyester diols such as polycaprolactone diols or polycarbonate diols). However, the amount of high MW polyol in the isocyanate-reactive composition should be less than 50 wt%, preferably less than 40 wt%, preferably less than 30 wt%, preferably less than 20 wt%, preferably less than 10 wt%, preferably less than 5 wt%, more preferably less than 2 wt% and most preferably less than 1 wt% based on the total weight of all isocyanate-reactive compounds in the reactive formulation.

[0090] According to an embodiment, the isocyanate-reactive composition may optionally contain a small amount of a high MW isocyanate-reactive compound with a molecular weight>500 g / mol, which is selected from polyester diols, polyether diols and / or polyester polyether diols (including specialty polyester diols such as polycaprolactone diols or polycarbonate diols) with a molecular weight of 500 g / mol to 10000 g / mol, preferably 500 g / mol to 5000 g / mol, more preferably 650 g / mol to 4000 g / mol. However, the amount of high MW polyol in the isocyanate-reactive composition should be less than 50% by weight, preferably less than 40% by weight, preferably less than 30% by weight, preferably less than 20% by weight, preferably less than 10% by weight, preferably less than 5% by weight, more preferably less than 2% by weight and most preferably less than 1% by weight based on the total weight of all isocyanate-reactive compounds in the reactive formulation.

[0091] According to an embodiment, the reactive formulation for forming the thermoplastic polyurethane (TPU) contains less than 5 wt % water, more preferably less than 4 wt % water, more preferably less than 3 wt % water, more preferably less than 2 wt % water, more preferably less than 1 wt % water, more preferably less than 0.5 wt % water, more preferably less than 0.3 wt % water, more preferably less than 0.2 wt % water, more preferably less than 0.1 wt % water, more preferably less than 0.05 wt % water, based on the total weight of the reactive formulation.

[0092] According to a preferred embodiment, the reactive formulation is free of water.

[0093] Isocyanate composition

[0094] According to an embodiment, the NCO value of the isocyanate composition is from 3 to 50, preferably from 5 to 33.6, more preferably from 10 to 33.6, more preferably from 15 to 33.6, more preferably from 20 to 33.6, more preferably from 25 to 33.6, most preferably from 30 to 33.6.

[0095] According to an embodiment, the isocyanate compound in the isocyanate composition is selected from aromatic isocyanate compounds, which contains at least 80 wt%, at least 85 wt%, at least 90 wt%, at least 95 wt% of difunctional isocyanate compounds based on the total weight of all isocyanate compounds in the isocyanate composition. Most preferably, the isocyanate composition contains at least 80 wt%, at least 85 wt%, at least 90 wt%, at least 95 wt%, and most preferably at least 98 wt% of 4,4'-diphenylmethane diisocyanate based on the total weight of the isocyanate composition.

[0096] According to an embodiment, the molecular number average isocyanate functionality of the isocyanate composition used to make the TPU material according to the present invention is 1.8 to 2.4, 1.8 to 2.2, more preferably 1.9-2.1, more preferably 1.95-2.05, more preferably 1.95-2.02, more preferably 1.95-2.015, more preferably 1.95-2.012, even more preferably 1.98-2.01 and most preferably 1.98-2.005.

[0097] According to an embodiment, the difunctional isocyanate (diisocyanate) can be selected from aliphatic diisocyanates selected from hexamethylene diisocyanate, isophorone diisocyanate, methylene dicyclohexyl diisocyanate and cyclohexane diisocyanate and / or aromatic diisocyanates selected from toluene diisocyanate (TDI), naphthalene diisocyanate, tetramethylxylene diisocyanate, phenylene diisocyanate, toluidine diisocyanate and in particular diphenylmethane diisocyanate (MDI).

[0098] According to an embodiment, the isocyanate composition used in the process of the present invention contains essentially (at least 95 wt. %, more preferably at least 98 wt. %, based on the total weight of the polyisocyanate composition) pure 4,4'-diphenylmethane diisocyanate.

[0099] According to an embodiment, the isocyanate composition used in the process of the invention contains a mixture of 4,4'-diphenylmethane diisocyanate with one or more other organic diisocyanates, in particular other diphenylmethane diisocyanates, for example the 2,4'-isomer optionally in combination with the 2,2'-isomer.

[0100] According to an embodiment, the isocyanate compound in the polyisocyanate composition may also be an MDI variant derived from an isocyanate composition containing at least 95% by weight of 4,4'-diphenylmethane diisocyanate. MDI variants are well known in the art and are used in the present invention, in particular including liquid products obtained by introducing carbodiimide groups into the polyisocyanate composition and / or by reacting with one or more polyols.

[0101] According to an embodiment, the isocyanate compound in the isocyanate composition may also be an isocyanate-terminated prepolymer, which is prepared by reacting an excess of an isocyanate having at least 80% by weight, at least 85% by weight, at least 90% by weight, at least 95% of 4,4'-diphenylmethane diisocyanate with a suitable difunctional polyol to obtain a prepolymer having the indicated NCO value. Methods for preparing prepolymers have been described in the art. The relative amounts of isocyanate and polyol depend on their equivalent weight and the desired NCO value, and can be easily determined by a person skilled in the art. The NCO value of the isocyanate-terminated prepolymer is preferably higher than 3%, preferably higher than 5%, more preferably higher than 8%, and most preferably higher than 10%.

[0102] According to an embodiment, the difunctional isocyanate compound in the isocyanate composition is present in the reactive formulation in an amount greater than 40 wt % (>40 wt %), preferably >41 wt %, more preferably >42 wt %, more preferably >43 wt %, more preferably >44 wt %, more preferably >45 wt %, more preferably >46 wt %, more preferably >47 wt %, more preferably >48 wt %, more preferably >49 wt %, more preferably >50 wt %, based on the total weight of the reactive formulation (excluding any additives and fillers, if used).

[0103] According to an embodiment, the aromatic isocyanate compound in the isocyanate composition is preferably selected from difunctional diphenylmethane diisocyanate (MDI), and the difunctional MDI is present in the reactive formulation in an amount greater than 40 wt% (>40 wt%), preferably >41 wt%, more preferably >42 wt%, more preferably >43 wt%, more preferably >44 wt%, more preferably >45 wt%, more preferably >46 wt%, more preferably >47 wt%, more preferably >48 wt%, more preferably >49 wt%, more preferably >50 wt%, based on the total weight of the reactive formulation (excluding any additives and fillers (if used)).

[0104] Additional additives and / or fillers

[0105] According to an embodiment, the reactive formulation may contain fillers such as wood chips, wood powder, wood chips, wood boards; shredded or layered paper and cardboard; sand, vermiculite, clay, cement and other silicates; ground rubber, ground thermoplastics, ground thermosets; honeycombs of any material such as cardboard, aluminum, wood and plastic; metal particles and plates; cork in granular form or in layers; natural fibers such as flax, hemp and sisal fibers; synthetic fibers such as polyamide, polyolefin, polyaramid, polyester and carbon fibers; mineral fibers such as glass fibers and rock wool fibers; mineral fillers such as BaSO4 and CaCO3; nanoparticles such as clay, inorganic oxides and carbon; glass beads, ground glass, hollow glass beads; expanded or expandable beads; untreated or treated waste such as ground, shredded, crushed or milled waste, in particular fly ash; woven and non-woven fabrics; and combinations of two or more of these materials.

[0106] According to an embodiment, the amount of additives and / or fillers used in the TPU material according to the invention is 0-95 wt.-%, based on the total weight of the final (filled / compounded) material.

[0107] According to an embodiment, the amount of additives and / or fillers used in the TPU material according to the present invention is 10-60 wt % based on the total weight of the final (filled / compounded) material. More preferably, the amount of additives and / or fillers is 20-50 wt % or even 30-40 wt %. In some cases, the most preferred filler is a fiber or thread-like material.

[0108] According to an embodiment, the amount of additives and / or fillers used in the TPU material according to the present invention is 40-95 wt % based on the total weight of the final (filled / compounded) material. More preferably, the amount of additives and / or fillers is 50-80 wt % or even 60-75 wt %. In some cases, the most preferred filler is a powder, sphere or fine particle.

[0109] According to an embodiment, the amount of additives and / or fillers used in the TPU material according to the present invention is >40 wt %, more preferably >50 wt %, more preferably >60 wt %, most preferably >70 wt %, based on the total weight of the final (filled / compounded) material.

[0110] According to an embodiment, due to the lower melt viscosity of the amorphous TPU material according to the present invention, a large amount of additives and / or fillers can be used / incorporated into the TPU material. Such higher additive and / or filler levels allow for superior performance to similar materials with lower filler levels. In some cases, preferred fillers used in large amounts are fibers, powders, spheres or fine particles.

[0111] According to an embodiment, the reactive formulation may further comprise solid polymer particles such as styrene-based polymer particles. Examples of styrene polymer particles include so-called "SAN" particles of styrene-acrylonitrile. Alternatively, a small amount of polymer polyol may be added to the isocyanate reactive composition as an additional polyol. An example of a commercially available polymer polyol is HYPERLITE® Polyol 1639, which is a polyether polyol modified with a styrene-acrylonitrile polymer (SAN) with a solid content of about 41% by weight (also referred to as a polymer polyol).

[0112] According to the embodiment, other conventional ingredients (additives and / or auxiliary agents) can be used to manufacture the TPU material according to the present invention. These ingredients include surfactants, flame retardants, fillers, pigments, stabilizers, foaming agents (including physical foaming agents and chemical foaming agents), antioxidants, plasticizers, pigments, processing additives (such as waxes), etc.

[0113] According to the embodiment, other polymers can be combined with the TPU material according to the present invention. They include but are not limited to low-density polyethylene and high-density polyethylene, polypropylene, polystyrene, polytetrafluoroethylene, polyvinyl chloride, polychlorotrifluoroethylene, polyamide, polyaramid, polyphenol formaldehyde, polyethylene terephthalate, polyacrylonitrile, polyimide, aromatic polyester, etc.; and combinations of two or more of these polymers with TPU materials.

[0114] According to an embodiment, suitable catalysts particularly accelerate the reaction between the NCO groups of the diisocyanate a) and the hydroxyl groups of the isocyanate-reactive compound and are selected from those known in the prior art, such as metal salt catalysts (such as organotin, organobismuth, organozinc, etc.), and amine compounds such as triethylenediamine (TEDA), N-methylimidazole, 1,2-dimethylimidazole, N-methylmorpholine, N-ethylmorpholine, triethylamine, N,N'-dimethylpiperazine, 1,3,5-tris(dimethylaminopropyl)hexadecene, Hydrotriazine, 2,4,6-tris(dimethylaminomethyl)phenol, N-methyldicyclohexylamine, pentamethyldipropylenetriamine, N-methyl-N'-(2-dimethylamino)-ethyl-piperazine, tributylamine, pentamethyldiethylenetriamine, hexamethyltriethylenetetramine, heptamethyltetraethylenepentamine, dimethylaminocyclohexylamine, pentamethyldipropylenetriamine, triethanolamine, dimethylethanolamine, bis(dimethylaminoethyl)ether, tris(3-dimethylamino)propylamine or its acid blocked derivatives, etc., and any mixtures thereof. The catalyst compound should be present in the reactive composition in a catalytically effective amount, typically about 0 to 5 weight percent, preferably 0 to 2 weight percent, and most preferably 0 to 1 weight percent based on the total weight of all reactive ingredients used.

[0115] Method for producing the TPU material according to the present invention

[0116] All reactants in the reactive formulation according to the present invention may be reacted at once or in a sequential manner. By premixing all or part of the isocyanate reactive compounds, a solution or suspension or dispersion is obtained. The various components used to make the composition of the present invention may be added in virtually any order. The method may be selected from a bulk method, an intermittent method or a continuous method, including a casting method and a reactive extrusion method.

[0117] As an example, the method for manufacturing the TPU material according to the present invention comprises at least the following steps:

[0118] i. premixing the isocyanate reactive compound, the catalyst compound and other additives and / or fillers, and then

[0119] ii. mixing the isocyanate composition with the composition obtained in step i) to form a reactive formulation, and

[0120] iii. reacting the reactive preparation obtained in step ii), and then

[0121] iv. optionally curing and / or annealing the TPU material obtained in step iii) at elevated temperature.

[0122] According to an embodiment, the step of mixing the polyisocyanate composition with the premixed composition obtained in step i) to form a reactive formulation is carried out using a two-component mixing system. According to an embodiment, the mixing system is a pressure mixing system. According to an embodiment, the pressure mixing system is a high-pressure mixing system that uses impact to mix materials.

[0123] According to an embodiment, the step of mixing the polyisocyanate composition with the premixed composition obtained in step i) to form a reactive formulation is performed using a two-component dynamic mixing system.

[0124] According to an embodiment, the step of mixing the polyisocyanate composition with the premixed composition obtained in step i) to form a reactive formulation is performed using a combination of impingement and dynamic mixing.

[0125] According to an embodiment, the method for manufacturing the TPU material according to the present invention uses Castech ® Casting process, batch process and / or reactive extrusion.

[0126] According to an embodiment, preferably no external heat is added to the reactive formulation, the exotherm of reaction being sufficient to obtain the final structure.

[0127] According to an embodiment, the step of reacting the reactive formulation obtained in step ii) is carried out in a mold, and the temperature of the mold can be varied to affect the skin properties. The elevated mold temperature can also prevent excessive heat loss, thereby facilitating conversion / molecular weight growth during polymerization.

[0128] According to an embodiment, the method for manufacturing the TPU material according to the present invention is carried out at an isocyanate index of 75 to 125, 80 to 120, 85 to 120, 88 to 120, 90 to 120, 90 to 110, 92 to 110, 95 to 110, 95 to 105, 95 to 102, 95 to 100.

[0129] TPU material according to the present invention

[0130] According to an embodiment, the TPU material has Tg>25°C, preferably Tg>35°C, preferably Tg>40°C, more preferably Tg>45°C, more preferably Tg>50°C, more preferably Tg>55°C, most preferably Tg>70°C.

[0131] According to an embodiment, the apparent density (ISO 1183-1) of the TPU material according to the present invention is 300-10000 kg / m 3 , 500-5000 kg / m 3 , 500-2500 kg / m 3 , 750-2500 kg / m 3 、900-2500 kg / m 3 , 900-2000 kg / m 3 , 900-1500 kg / m 3 , 900-1300 kg / m 3 1000-1300 kg / m 3 1100-1300 kg / m 3 , measured according to ISO1183-1.

[0132] According to an embodiment, the apparent Shore D hardness (measured according to DIN ISO 7619-2) of the TPU material according to the present invention is 50 to 100, more preferably 60 to 100, more preferably 70 to 100, more preferably 70 to 90, most preferably 75 to 85.

[0133] According to an embodiment, the elongation (according to DIN 53504) of the TPU material according to the present invention is 1 to 500%, more preferably 1 to 400%, more preferably 1 to 300%, more preferably 1 to 200%, more preferably 1 to 100%, more preferably 1 to 50%, most preferably 1 to 30%.

[0134] According to an embodiment, the flexural modulus (according to ISO 178) of the TPU material according to the present invention is 300 to 15000 MPa, more preferably 500 to 12000 MPa, more preferably 800 to 10000 MPa, more preferably 800 to 6000 MPa, more preferably 800 to 5000 MPa, more preferably 1200 to 3500 MPa, most preferably 1500 to 2700 MPa.

[0135] According to an embodiment, the tensile strength at break (according to DIN 53504) of the TPU material according to the invention is 5 to 150 MPa, more preferably 15 to 120 MPa, more preferably 30 to 100 MPa, more preferably 40 to 90 MPa, most preferably 50 to 80 MPa.

[0136] According to an embodiment, the tensile strength of the TPU material according to the invention at maximum load (according to DIN53504) is 5 to 150 MPa, more preferably 15 to 120 MPa, more preferably 30 to 100 MPa, more preferably 40 to 90 MPa, most preferably 50 to 80 MPa.

[0137] According to an embodiment, the TPU material according to the present invention is manufactured using a reactive formulation, wherein the aromatic dicarboxylic acid-based diol chain extender is a terephthalic acid-based polyester diol chain extender manufactured from recycled PET, and the TPU material comprises a recycled content of ≥2 wt%, more preferably ≥5 wt%, more preferably ≥10 wt%, more preferably ≥15 wt%, more preferably ≥20 wt%, most preferably ≥25 wt%, based on the total weight of the TPU material (excluding any filler). When fillers are included in the calculation of the recycled content of the TPU material, the TPU material contains a recycled content of ≥1 wt%, more preferably ≥2 wt%, more preferably ≥3 wt%, more preferably ≥4 wt%, most preferably ≥5 wt%.

[0138] The TPU material according to the present invention has thermoplastic properties. Therefore, the present invention further provides a method for regenerating and / or remelting the thermoplastic polyurethane according to the present invention into new applications without significantly degrading the thermoplastic polymer matrix compared to the high flexural modulus and high hardness materials of the prior art such as high hard block TPU (with low degradation temperature) or thermosetting materials. Compared to these materials, the TPU material according to the present invention can be more easily regenerated and / or remelted.

[0139] According to an embodiment, the remelting / regeneration of the thermoplastic TPU material according to the present invention is performed by heating and / or compression processing at a temperature above the melting temperature of the thermoplastic material.

[0140] According to an embodiment, the remelting / regeneration of the thermoplastic TPU material according to the present invention is carried out by a process at a temperature above the melting temperature of the thermoplastic material to recover and / or separate the TPU from any spent filler or fiber.

[0141] According to an embodiment, the regeneration of the thermoplastic TPU material according to the invention is carried out by a process using a solvent or a combination of solvents.

[0142] According to an embodiment, the remelting / regeneration of the thermoplastic TPU material according to the present invention is performed by a process using a solvent or a combination of solvents to recover and / or separate the TPU from any spent filler or fiber.

[0143] According to an embodiment, the remelting / regeneration of the thermoplastic material according to the invention is carried out in an extruder at a temperature above the melting temperature of the thermoplastic material. By further adding a blowing agent in the extruder, a foamed recycled TPU foam can be obtained.

[0144] According to an embodiment, the TPU material can be processed at a temperature below 250°C, preferably a temperature <245°C, preferably a temperature <240°C, preferably a temperature <235°C, preferably a temperature <230°C, preferably a temperature <225°C, preferably a temperature <220°C, preferably a temperature <215°C, preferably a temperature <210°C, preferably a temperature <205°C, preferably a temperature <200°C, preferably a temperature <195°C, preferably a temperature <190°C, preferably a temperature <185°C, and most preferably a temperature <180°C.

[0145] According to an embodiment, the TPU material can be processed by all conventional methods used in thermoplastics processing, for example by injection molding, extrusion, calendering, thermoforming, roll milling, rotational molding, sintering methods or from solution (using suitable solvents). Processing methods without using solvents are most preferred.

[0146] The invention also discloses a thermally reformed material based on the thermoplastic material according to the invention.

[0147] In some cases it is preferred to use the thermally reformed / recycled thermoplastic material in the same field of application as the original application. Examples are the use of the thermoplastic material according to the invention as a composite material in construction applications, flooring applications.

[0148] The invention is illustrated by means of the following examples. Example

[0149] Chemicals used:

[0150] Examples described in Table 1 - Sample preparation

[0151] Comparative Example 1 and Comparative Example 2 (CE1 and CE2) described in Table 1 were thermoplastic materials obtained from respective suppliers and injection molded according to the supplier's guidelines.

[0152] Comparative Example 3 (CE3) and Example 1 (E1) of the present invention were prepared by a batch process. The thermoplastic polyurethane samples were made using a Cas.Tech DB9 casting elastomer machine. The raw materials ("isocyanate blend", "chain extender blend", "isocyanate reactive blend", additives) were maintained at 50±1°C in a material tank (only in the case of isocyanate 1, a temperature of 60°C was used for this particular material tank). In Example E1, two different isocyanate reactive materials were used, processed using separate raw material tanks (however, similar / same results can also be obtained using pre-blends of different isocyanate reactive materials stored in a single raw material tank). The materials were mixed at a speed of 5000 RPM in a mixing head and output at 1900 g / min. The samples were cast in a vertical sheet mold set to a temperature of 120°C to prepare A4 size samples of 4 mm thickness. The samples were demoulded after curing (see demoulding time in Table 1) to obtain a thermoplastic polyurethane material that was solid at room temperature.

[0153] The properties of the various comparative samples and the samples of the present invention shown in Table 1 were measured using the following methods.

[0154] The results in Table 1 clearly show that the inventive TPU material (E1) has an increased Shore D hardness and a higher flexural modulus compared to Comparative Example 1 (CE1), while maintaining similar processing and degradation temperatures. Compared to Comparative Examples 1 and 2 (CE1 and CE2), the inventive TPU material (E1) shows similar performance (Shore D hardness and higher flexural modulus), but with a lower processing temperature (see minimum extrusion processing temperature). The lower processing temperature of the inventive examples is further demonstrated using the MVR measurement results of the inventive examples (E1) at different temperatures below 220°C.

[0155] Example 4 (CE4) has difunctional diphenylmethane diisocyanate (MDI) in the reactive formulation in an amount less than 40 wt% based on the total weight of the reactive formulation (excluding any optional additives and fillers). CE4 contains only 35.7 wt% of MDI isomers. Despite the presence of an aromatic carboxylic acid based diol chain extender (Terol 250) with a molecular weight of <500 g / mol, the Tg of the TPU in CE4 is 34°C.

[0156] Table 1

[0157] Table 2 below is an example of a temperature profile of a Haake extruder for Example E1 of the present invention. The extrusion temperature for this experiment was 200°C (using the highest temperature zone of the extruder, which is the minimum requirement for extruding the material). This demonstrates that the material E1 of the present invention can be processed at ≤220°C, and therefore at significantly lower temperatures than CE1 and CE2.

[0158] Table 2

[0159] Inventive Example (E1) has the additional benefit of containing a polyol (Terol 250) made from recycled materials (pre- and post-consumer) (approximately about 55% by weight in the polyol). Inventive Example E1 has a recycled content of about 22% by weight (including both pre- and post-consumer recycled materials).

Claims

1. A reactive formulation for forming a thermoplastic polyurethane (TPU) having a Shore D hardness (measured according to DIN ISO 7619-2) of 50 to 100 and a glass transition temperature (Tg, measured according to ISO 11357-2:2020) above room temperature, the reactive formulation comprising at least: - an isocyanate composition comprising at least one difunctional isocyanate compound, and an isocyanate-reactive composition comprising at least 10% by weight, based on the total weight of all chain extenders in the isocyanate-reactive composition, of an isocyanate-reactive compound selected from at least one diol chain extender based on aromatic dicarboxylic acids, the diol chain extender being selected from polyester diol chain extenders based on terephthalic acid made from recycled PET having a molecular weight of <500 g / mol, and - optionally a catalyst compound, and -Optional other additives and / or fillers wherein the reactive formulation has a hard block content of >70 wt % based on the total weight of the isocyanate composition and the isocyanate reactive composition, an isocyanate index of 75 to 125, and a number average isocyanate functionality and a number average hydroxyl functionality of 1.8 to 2.

5.

2. The reactive formulation according to any one of the preceding claims, wherein the isocyanate-reactive composition has a hydroxyl functionality of 1.8 to 2.4 and comprises at least 20 wt.-%, based on the total weight of all chain extenders in the isocyanate-reactive composition, of a diol chain extender based on an aromatic carboxylic acid with a molecular weight of <500 g / mol, preferably at least 30 wt.-%, preferably at least 40 wt.-%, preferably at least 50 wt.-%, preferably at least 60 wt.-%, preferably at least 70 wt.-%, preferably at least 80 wt.-%, most preferably at least 90 wt.-%, based on the total weight of all chain extenders in the isocyanate-reactive composition, of a diol chain extender based on an aromatic carboxylic acid with a molecular weight of <500 g / mol.

3. The reactive formulation according to any one of the preceding claims, wherein the TPU has a Tg (measured according to ISO 11357-2:2020) > 35°C, preferably Tg > 40°C, preferably Tg > 45°C, more preferably Tg > 50°C, more preferably Tg > 55°C, most preferably > 70°C.

4. The reactive formulation according to any one of the preceding claims, wherein the isocyanate-reactive composition comprises an aromatic-based diol and an aliphatic-based diol such that at least 20 wt.-% of the diol, preferably >30 wt.-%, preferably >40 wt.-%, preferably >50 wt.-%, preferably >60 wt.-%, preferably >70 wt.-%, more preferably >75 wt.-% of the diol, based on the total weight of the isocyanate-reactive composition, is selected from diols based on aromatic dicarboxylic acids.

5. The reactive formulation according to any one of the preceding claims, wherein the aromatic dicarboxylic acid based diol chain extender is based on phthalic acid selected from phthalic acid, isophthalic acid and / or terephthalic acid, more preferably the aromatic diol chain extender is based on terephthalic acid, most preferably the aromatic diol chain extender is a terephthalic acid based polyester diol chain extender.

6. The reactive formulation according to any one of the preceding claims, comprising less than 1 wt. % water, preferably less than 0.5 wt. % water, more preferably less than 0.2 wt. % water, more preferably less than 0.1 wt. % water, more preferably less than 0.05 wt. % water.

7. The reactive formulation according to any one of the preceding claims, which is free of water.

8. The reactive formulation according to the preceding claim, wherein the aromatic isocyanate compound in the isocyanate composition is selected from difunctional diphenylmethane diisocyanate isomers (MDI), and the MDI isomers are present in the reactive formulation in an amount of >40 wt%, more preferably >41 wt%, more preferably >42 wt%, more preferably >43 wt%, more preferably >44 wt%, more preferably >45 wt%, more preferably >46 wt%, more preferably >47 wt%, more preferably >48 wt%, more preferably >50 wt%, based on the total weight of the reactive formulation, excluding any additives and fillers.

9. The reactive formulation according to the preceding claim, wherein the reactive formulation has a hardblock content of >70 wt%, more preferably >75 wt%, preferably >80 wt%, more preferably >85 wt%, most preferably 90-100 wt%.

10. The reactive formulation according to the preceding claims, wherein the number average functionality of the isocyanate-reactive compound and / or isocyanate compound and / or the overall reactive formulation (including all isocyanate compounds and isocyanate-reactive compounds) is from 1.8 to 2.5, more preferably 1.9-2.2, more preferably 1.95-2.05, more preferably 1.95-2.02, more preferably 1.95-2.015, more preferably 1.95-2.012, even more preferably 1.98-2.01 and most preferably 1.98-2.

005.

11. The reactive foam formulation according to the preceding claim, wherein the isocyanate composition has an NCO value of 3 to 50, preferably 5 to 33.6, more preferably 10 to 33.6, more preferably 15 to 33.6, more preferably 20 to 33.6, more preferably 25 to 33.6, most preferably 30 to 33.

6.

12. The reactive formulation according to the preceding claim, wherein the isocyanate compound in the isocyanate composition is selected from aromatic isocyanate compounds, preferably the isocyanate composition contains at least 80 wt%, at least 85 wt%, at least 90 wt%, at least 95 wt%, and most preferably at least 98 wt% of 4,4'-diphenylmethane diisocyanate, based on the total weight of the isocyanate composition.

13. The reactive formulation according to the preceding claim, wherein the isocyanate index of the reactive foam formulation is 75 to 125, 80 to 120, 85 to 120, 88 to 120, 90 to 120, 90 to 110, 92 to 110, 95 to 110, 95 to 105, 95 to 102, 95 to 100.

14. The reactive formulation according to the preceding claim, wherein the aromatic dicarboxylic acid based diol chain extender has a molecular weight of 45 to 500 g / mol, more preferably 150 to 500 g / mol, most preferably 250 to 500 g / mol.

15. Method for producing a thermally regenerable TPU by combining and reacting the compounds of the reactive formulation according to any one of the preceding claims 1 to 14.

16. A thermoplastic polyurethane (TPU) material produced by combining and reacting the compounds of the reactive formulation according to any one of the preceding claims 1 to 14, wherein the thermoplastic polyurethane (TPU) material has a glass transition temperature (Tg) > room temperature, preferably a Tg above 40°C, more preferably above 55°C, a flexural modulus of 300-15000 MPa (measured according to ISO 178), most preferably 1500-2700 MPa, and a tensile strength at break (according to DIN 53504) of 5 to 150 MPa.

17. The TPU material according to claim 16, which is made using a reactive formulation, wherein the aromatic dicarboxylic acid-based diol chain extender is a terephthalic acid-based polyester diol chain extender made from recycled PET, and the TPU material contains a recycled content of ≥2 wt%, more preferably ≥5 wt%, more preferably ≥10 wt%, more preferably ≥15 wt%, more preferably ≥20 wt%, and most preferably ≥25 wt%, based on the total weight of the TPU material (excluding any filler).

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