Thermoplastic polyurethane

Abstract

Provided is a thermoplastic polyurethane containing a structural unit (A) derived from a polymer polyol (a) having a hydroxyl group at an end thereof, a structural unit (B) derived from a polyisocyanate (b), and a structural unit (C) derived from a chain extender (c), the polymer polyol (a) including structural units derived from a branched polyol (a1) and a C7-11 polycarboxylic acid (a2), the thermoplastic polyurethane has a number average molecular weight of 500 or more, and contains 50-90% by mass of the constituent unit (A), 8-45% by mass of the constituent unit (B), and 2-10% by mass of the constituent unit (C) per 100% by mass of the total constituent unit of the thermoplastic polyurethane.

Description

Technical Field

[0001] This invention relates to a thermoplastic polyurethane. Background Technology

[0002] Thermoplastic polyurethane (TPU) is suitable for extruded and injection-molded products such as films. For example, low-hardness TPU can be used in medical catheters, shoe cushioning materials, and protective films for resins and metals.

[0003] Generally, TPU is manufactured through the polycondensation of polyols, isocyanates, and chain extenders. Furthermore, polyol units are considered the main component of the soft segments. Conversely, since chain extenders are more reactive with isocyanates than polyols, units composed of isocyanates and chain extenders are generally considered the main component of the hard segments.

[0004] For example, Patent Document 1 discloses a plasticizer-free, low-hardness thermoplastic polyurethane resin composition comprising: a) 70 to 80% by weight of a polyol containing poly(3-methylpentanediol adipate) diol, b) 13 to 20% by weight of diisocyanate, c) 2 to 6% by weight of chain extender; and d) 0.001 to 0.1% by weight of catalyst.

[0005] Patent Document 2 discloses a polyurethane elastomer comprising 70-80% hydrophobic polyester polyol, 5-8% chain extender, and 15-25% diphenylmethane diisocyanate, with a Shore hardness of 55-75A. The hydrophobic polyester polyol is formed by the polymerization of a long-chain diacid and a diol, and has a molecular weight of 2000-6000 g / mol. The molar ratio of the long-chain diacid to the diol is 1:1.05-1.25. The diol is a side-chain diol or a combination of a side-chain diol and a straight-chain diol. The molar ratio of the straight-chain diol in the combination of the side-chain diol and the straight-chain diol is 0-20%.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Korean Patent Publication No. 10-2006-0092516

[0009] Patent Document 2: Description of Chinese Patent Application Publication No. 112142960 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, when TPU is used in applications such as automotive parts or industrial components, it is sometimes used in high-temperature environments, and it is necessary to maintain its strength, rubber elasticity, and other properties even at high temperatures.

[0012] In addition, for example, when TPU is used in low-temperature environments such as conveyor belts for processing food at low temperatures, or in cold regions, it is necessary to maintain low-temperature properties such as hardness and flexibility even at low temperatures.

[0013] In order to be usable in such environments, in recent years, TPU has been required to have both good heat resistance and excellent low-temperature properties.

[0014] However, the inventors found that, in the case of the low-hardness thermoplastic polyurethane resin composition described in Patent Document 1, although the low-temperature properties are good, the heat resistance cannot be fully utilized.

[0015] Furthermore, the inventors found that, in the case of the polyurethane elastomer described in Patent Document 2, although the heat resistance is good, the low-temperature properties are not sufficient.

[0016] Therefore, the object of the present invention is to provide a thermoplastic polyurethane that can achieve both good heat resistance and excellent low-temperature properties.

[0017] Methods for solving problems

[0018] The inventors have conducted repeated and in-depth research and found that the above-mentioned problems can be solved by manufacturing thermoplastic polyurethane that meets specific requirements.

[0019] That is, the present invention includes the following inventions.

[0020] [1] A thermoplastic polyurethane comprising a structural unit (A) derived from a high molecular weight polyol (a) having hydroxyl groups at the ends, a structural unit (B) derived from a polyisocyanate (b) and a structural unit (C) derived from a chain extender (c).

[0021] The aforementioned high-molecular-weight polyol (a) comprises structural units derived from branched polyols (a1) and polycarboxylic acids (a2) having 7 to 11 carbon atoms, and has a number-average molecular weight of 500 or higher.

[0022] Of the total 100% by mass of the above thermoplastic polyurethane structural units, 50-90% by mass of structural units (A), 8-45% by mass of structural units (B), and 2-10% by mass of structural units (C) are included.

[0023] [2] According to the thermoplastic polyurethane described in [1] above, in all 100% by mass of the thermoplastic polyurethane structural units, there are 60 to 90% by mass of structural units (A), 8 to 38% by mass of structural units (B) and 2 to 8% by mass of structural units (C).

[0024] [3] According to the thermoplastic polyurethane described in [1] or [2] above, wherein the branched polyol (a1) is 3-methyl-1,5-pentanediol.

[0025] [4] The thermoplastic polyurethane described in any one of [1] to [3] above, wherein the chain extender (c) is a diol with a molecular weight of less than 500.

[0026] [5] The thermoplastic polyurethane described in any of [1] to [4] above, wherein the hardness of the hardness tester A measured according to JIS K 7215-1986 is HDA95 or less.

[0027] [6] The thermoplastic polyurethane described in any one of [1] to [5] above, wherein the hardness of the hardness tester A measured according to JIS K 7215-1986 is HDA80 or less.

[0028] [7] The thermoplastic polyurethane described in any of [1] to [6] above has a crystallization temperature of -15°C or no crystallization temperature.

[0029] [8] The thermoplastic polyurethane described in any one of [1] to [7] above, wherein the complex elastic modulus E of the sheet produced by injection molding at 150°C The complex elastic modulus E relative to 25℃ The ratio of [E] (150℃) / E (25℃) is above 0.15.

[0030] [9] A method for manufacturing thermoplastic polyurethane, comprising reacting at least 50-90% by mass of a high molecular weight polyol (a) having terminal hydroxyl groups, 8-45% by mass of a polyisocyanate (b), and 2-10% by mass of a chain extender (c) in 100% by mass of the total raw material components of thermoplastic polyurethane to obtain thermoplastic polyurethane.

[0031] The aforementioned high molecular weight polyol (a) is a polyol containing structural units derived from branched polyols (a1) and polycarboxylic acids (a2) with 7 to 11 carbon atoms, and having a number average molecular weight of 500 or more.

[0032]

[10] According to the method for manufacturing thermoplastic polyurethane described in [9] above, in which at least 60 to 90% by mass of a high molecular weight polyol (a) having hydroxyl groups at the end, 8 to 38% by mass of a polyisocyanate (b) and 2 to 8% by mass of a chain extender (c) are reacted to obtain thermoplastic polyurethane in a total of 100% by mass of the raw material components of the above thermoplastic polyurethane.

[0033]

[11] In the method for manufacturing thermoplastic polyurethane as described in [9] or

[10] above, a catalyst (d) of 0.1 to 1000 ppm by mass is used relative to the total amount of the above-mentioned high molecular weight polyol (a), the above-mentioned polyisocyanate (b) and the above-mentioned chain extender (c).

[0034]

[12] A thermoplastic polyurethane composition comprising the thermoplastic polyurethane described in any one of [1] to [8] above.

[0035]

[13] A molded article comprising the thermoplastic polyurethane described in any one of [1] to [8] above.

[0036] Invention Effects

[0037] According to the present invention, a thermoplastic polyurethane that can achieve both good heat resistance and excellent low-temperature properties can be provided. Detailed Implementation

[0038] The following description is based on examples of embodiments of the present invention (hereinafter also referred to as "one aspect of the present invention"). However, the embodiments shown below are illustrative of the technical concept of the present invention, and the present invention is not limited to the following description.

[0039] Any method or combination of any of the items described in this specification is also included in this invention.

[0040] This specification provides preferred embodiments; however, combinations of two or more preferred embodiments are also preferred. The criteria for determining preference can be arbitrarily chosen; for example, it can be said that a combination of criteria for determining preference is more preferred.

[0041] In this specification, unless otherwise specified, the description of a numerical range as "XX~YY" means "above XX and below YY" (XX represents the lower limit value, and YY represents the upper limit value). For example, when a numerical range is abbreviated as "10~90", it means the range of 10 and below 90.

[0042] In this specification, the lower and upper limits of numerical ranges (content of each component, content of each structural unit, values ​​calculated from them, and various physical properties, etc.) recorded in stages can be combined independently. For example, from the description of "preferred to be 10 to 90, more preferably 30 to 60" for the same matter, the "preferred lower limit (10)" and the "more preferably upper limit (60)" can be combined and set as "10 to 60".

[0043] Furthermore, regarding the numerical range, for example, based on the description of "preferably 10 to 90, more preferably 30 to 60", the upper limit value can be not specifically specified, but only the lower limit value can be specified as "10 or more" or "30 or more". Similarly, the lower limit value can be not specifically specified, but only the upper limit value can be specified as "90 or less" or "60 or less". The same applies when the upper end of the above numerical range is "less than" and when the lower limit is "greater than".

[0044] Similarly, for example, from the descriptions of "preferably 10 or more, more preferably 30 or more" and "preferably 90 or less, more preferably 60 or less" for the same matter, the "preferred lower limit (10)" and "more preferably upper limit (60)" can be combined to set "10 or more and 60 or less". Furthermore, similarly, only the lower limit side can be specified as "10 or more" or "30 or more", and similarly, only the upper limit side can be specified as "90 or less" or "60 or less". The same applies when the descriptions of "above" and "below" in the above explanation are respectively written as "greater than" and "less than". That is, for example, based on the description of "preferably greater than 10 and less than 90, more preferably 30 or more and 60 or less", the upper and lower limits can be combined to set "greater than 10 and 60 or less" and "30 or more and less than 90".

[0045] In addition, unless otherwise specified, the terms "low temperature characteristics" and "heat resistance" in this specification refer to the "low temperature characteristics" and "heat resistance" of the thermoplastic polyurethane as an embodiment of the present invention, specifically the characteristics evaluated using the methods described in the examples.

[0046] [Thermoplastic polyurethane]

[0047] As one aspect of the present invention, the thermoplastic polyurethane comprises structural units (A) derived from a high molecular weight polyol (a) having hydroxyl groups at the ends, structural units (B) derived from a polyisocyanate (b), and structural units (C) derived from a chain extender (c).

[0048] The aforementioned high-molecular-weight polyol (a) comprises structural units derived from branched polyols (a1) and polycarboxylic acids (a2) having 7 to 11 carbon atoms, and has a number-average molecular weight of 500 or higher.

[0049] Of the total 100% by mass of the above thermoplastic polyurethane structural units, 50-90% by mass of structural units (A), 8-45% by mass of structural units (B), and 2-10% by mass of structural units (C) are included.

[0050] The aforementioned high-molecular-weight polyol (a) comprises structural units derived from branched polyols (a1) and polycarboxylic acids (a2) having 7 to 11 carbon atoms, and has a number-average molecular weight of 500 or higher.

[0051] Of the total 100% by mass of the above-mentioned thermoplastic polyurethane structural units, it is preferred to include 60-90% by mass of structural unit (A), 8-38% by mass of structural unit (B), and 2-8% by mass of structural unit (C).

[0052] The thermoplastic polyurethane described above will now be described. In this specification, unless otherwise specified, "the above-described TPU" refers to the thermoplastic polyurethane described above as an embodiment of the present invention.

[0053] <Structural Unit (A)>

[0054] The structural unit (A) is derived from a high molecular weight polyol (a) with hydroxyl groups at the ends. Furthermore, structural unit (A) primarily constitutes the soft segment in the aforementioned TPU.

[0055] (Polyols (a))

[0056] The high molecular weight polyol (a) contains structural units derived from branched polyols (a1) and polycarboxylic acids (a2) with 7 to 11 carbon atoms, and has a number average molecular weight of 500 or more.

[0057] In this specification, "high molecular weight polyol" refers to polyols with an index-average molecular weight of 500 or higher.

[0058] If the number average molecular weight of the polymeric polyol (a) is 500 or more, it is preferable from the viewpoint of the mechanical properties of the resulting TPU. Furthermore, if the number average molecular weight of the polymeric polyol (a) is 10,000 or less, it is preferable from the viewpoint of ease of material feeding during the synthesis of the TPU. For the same reason, the number average molecular weight (Mn) of the polymeric polyol (a) is preferably 500 to 10,000, more preferably 800 to 8,500, further preferably 1,000 to 7,500, and even more preferably 1,500 to 6,500.

[0059] The number-average molecular weight of the high molecular weight polyol (a) is the value determined using the method described in the examples.

[0060] Regarding the number of hydroxyl groups in each molecule of the polymeric polyol (a), from the viewpoint of the viscosity of the polymeric polyol (a) and the melt viscosity of the resulting TPU, it is preferably 2 to 10, more preferably 2 to 5, further preferably 2 to 4, even more preferably 2 to 3, and even more preferably 2. That is, the polymeric polyol (a) is more preferably a polymeric diol or a polymeric triol, and even more preferably a polymeric diol.

[0061] [Branched polyols (a1)]

[0062] Polyols (a) have high mobility due to the inclusion of structural units derived from branched polyols (a1), thus increasing the mobility of the soft segments in the aforementioned TPU. Consequently, even when the proportion of hard segments in the aforementioned TPU is low, crystallization of the soft segments is less likely to occur. As a result, the aforementioned TPU does not crystallize, or can have a lower crystallization temperature (Tc), for example, below -15°C, thereby exhibiting excellent low-temperature properties. Therefore, the aforementioned TPU can be appropriately used in low-temperature environments.

[0063] The branched polyol (a1) can be any alcohol having a branched structure and having two or more hydroxyl groups. Regarding the number of hydroxyl groups in each molecule of the branched polyol (a1), from the viewpoint of the viscosity of the resulting polymeric polyol (a), it is preferably 2 to 10, more preferably 2 to 5, further preferably 2 to 4, even more preferably 2 to 3, and even more preferably 2. That is, the branched polyol (a1) is further preferably a branched diol.

[0064] As a branched polyol (a1), a branched aliphatic diols are preferred.

[0065] As branched aliphatic diols, diols with 3 to 11 carbon atoms are preferred, diols with 4 to 9 carbon atoms are more preferred, diols with 4 to 7 carbon atoms are even more preferred, and diols with 5 to 7 carbon atoms are even more preferred. Examples of branched aliphatic diols include 1,2-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-1,4-butanediol, 1,2-pentanediol, 1,3-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 1,4-pentanediol, 2-methyl-1,5-pentanediol, and 3-methyl-1 5-Pentanediol, 2-Ethyl-2,4-Pentanediol, 2-Ethyl-1,5-Pentanediol, 2,4-Dimethyl-1,5-Pentanediol, 2,4-Diethyl-1,5-Pentanediol, 1,2-Hexanediol, 1,3-Hexanediol, 1,4-Hexanediol, 1,5-Hexanediol, 2-Ethyl-1,6-Hexanediol, 2-Methyl-1,8-Octanediol, 2,7-Dimethyl-1,8-Octanediol, 2-Methyl-1,9-Nonadiol, 2,8-Dimethyl-1,9-Nonadiol, 2-Butyl-2-Ethyl-1,3-Propanediol, etc. They can be used alone or in combination of two or more.

[0066] Furthermore, from the viewpoint of high reactivity with polyisocyanates, at least one branched aliphatic diol selected from those in which both hydroxyl groups are primary hydroxyl groups is preferred as the branched aliphatic diol. From the viewpoint of both hydroxyl groups having the same reactivity with polyisocyanates and being able to provide homogeneous thermoplastic polyurethane, at least one branched aliphatic diol with mirror symmetry is more preferred. From the viewpoint of availability, at least one branched aliphatic diol selected from 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and 3-methyl-1,5-pentanediol is further preferred as the branched aliphatic diol. From the viewpoint of the high molecular weight polyol (a) having low viscosity, 3-methyl-1,5-pentanediol is even more preferred as the branched aliphatic diol.

[0067] Examples of branched aliphatic diols in which both hydroxyl groups are primary hydroxyl groups include 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-1,4-butanediol, 2-methyl-1,5-pentanediol, and 3-methyl-1,5-propanediol. 2-Pentanediol, 2-Ethyl-1,5-Pentanediol, 2,4-Dimethyl-1,5-Pentanediol, 2,4-Diethyl-1,5-Pentanediol, 2-Ethyl-1,6-Hexanediol, 2-Methyl-1,8-Octanediol, 2,7-Dimethyl-1,8-Octanediol, 2-Methyl-1,9-Nonadiol, 2,8-Dimethyl-1,9-Nonadiol, 2-Butyl-2-Ethyl-1,3-Propanediol, etc. They can be used alone or in combination of two or more.

[0068] Examples of the aforementioned branched aliphatic diols with mirror symmetry include 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2-butyl-2-ethyl-1,3-propanediol. They can be used individually or in combination of two or more.

[0069] The structural units of a high molecular weight polyol (a) can be derived from other polyols besides branched polyols (a1).

[0070] Other polyols mentioned above include, for example, straight-chain aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol; alicyclic diols such as cyclohexanediol and cyclohexanediol; and diols obtained by polymerizing cyclic monomers with branched polyols (a1) or other polyols mentioned above as initiators, such as polyethylene glycol, polypropylene glycol, poly1,4-butanediol, and polycaprolactone, with a number average molecular weight of 300 to 3000.

[0071] From the viewpoint of superior low-temperature properties, in the polymer polyol (a), the content of structural units from branched polyols (a1) is preferably 30 to 100% by mass, more preferably 50 to 100% by mass, further preferably 60 to 100% by mass, even more preferably 75 to 100% by mass, even more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and may also be 100% by mass.

[0072] [Polycarboxylic acids with 7 to 11 carbon atoms (a2)]

[0073] Polymer polyols (a) contain structural units derived from polycarboxylic acids (a2) with 7 to 11 carbon atoms.

[0074] If the polycarboxylic acid (a2) has 7 or more carbon atoms, the soft segment exhibits higher hydrophobicity compared to polycarboxylic acids with 6 or fewer carbon atoms, thus improving phase separation from the highly hydrophilic hard segment. Furthermore, the improved phase separation between the soft and hard segments results in stronger cohesion of the hard segment, making it less prone to decrease in the complex modulus of elasticity of the aforementioned TPU even at higher temperatures, thus enhancing the heat resistance of the TPU.

[0075] If the number of carbon atoms in the polycarboxylic acid (a2) is 11 or less, the reduction in the mobility of the structural units derived from the polycarboxylic acid in the soft segment is suppressed, thus suppressing the reduction in the mobility of the soft segment and making the low-temperature properties of the aforementioned TPU excellent.

[0076] The polycarboxylic acid (a2) preferably has 7 to 10 carbon atoms, but it can also have 8 to 10, or 9 or 10 carbon atoms.

[0077] As a polycarboxylic acid (a2), any carboxylic acid or its anhydride having 7 to 11 carbon atoms and having two or more carboxyl groups is acceptable. Regarding the number of carboxyl groups in each molecule of the aforementioned polycarboxylic acid (a2), from the viewpoint of the viscosity of the resulting polymeric polyol (a), it is preferably 2 to 10, more preferably 2 to 5, further preferably 2 to 4, even more preferably 2 to 3, and even more preferably 2. That is, the polycarboxylic acid (a2) is further preferably a dicarboxylic acid having 7 to 11 carbon atoms.

[0078] Examples of dicarboxylic acids having 7 to 11 carbon atoms include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids. Preferably, the dicarboxylic acid having 7 to 11 carbon atoms is an aliphatic dicarboxylic acid.

[0079] Examples of aliphatic dicarboxylic acids with 7 to 11 carbon atoms include pimelic acid (7 carbon atoms), octanoic acid (8 carbon atoms), azelaic acid (9 carbon atoms), sebacic acid (10 carbon atoms), and undecanoic acid (11 carbon atoms).

[0080] Examples of the aforementioned alicyclic dicarboxylic acids with 7 to 11 carbon atoms include 1,1-cyclohexanedicarboxylic acid (8 carbon atoms), 1,2-cyclohexanedicarboxylic acid (8 carbon atoms), 1,3-cyclohexanedicarboxylic acid (8 carbon atoms), and 1,4-cyclohexanedicarboxylic acid (8 carbon atoms).

[0081] Examples of aromatic dicarboxylic acids with 7 to 11 carbon atoms include phthalic acid (8 carbon atoms), isophthalic acid (8 carbon atoms), and terephthalic acid (8 carbon atoms).

[0082] These polycarboxylic acids (a2) can be used alone or in combination with two or more.

[0083] Polymer polyols (a) can contain structural units of polycarboxylic acids other than polycarboxylic acids (a2) with carbon numbers of 7 to 11, which can serve as polycarboxylic acid components.

[0084] Other examples of the aforementioned polycarboxylic acids include aliphatic dicarboxylic acids with 7 to 11 carbon atoms such as succinic acid, glutaric acid, adipic acid, and dodecanoic acid; alicyclic dicarboxylic acids with 7 to 11 carbon atoms; and aromatic dicarboxylic acids with 7 to 11 carbon atoms such as 2,6-naphthalenedicarboxylic acid.

[0085] In the polymer polyol (a), the content of structural units derived from polycarboxylic acids (a2) having 7 to 11 carbon atoms is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, further preferably 70 to 100% by mass, even more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and may also be 100% by mass, from the viewpoint of easily balancing excellent low-temperature properties and heat resistance.

[0086] In the polymer polyol (a), the total content of structural units from branched polyols (a1) and structural units from polycarboxylic acids (a2) having 7 to 11 carbon atoms is preferably 60 to 100% by mass, more preferably 80 to 100% by mass, further preferably 85 to 100% by mass, even more preferably 90 to 100% by mass, even more preferably 95 to 100% by mass, and may also be 100% by mass, from the viewpoint of easily balancing better low-temperature properties and heat resistance.

[0087] [Method for manufacturing high molecular weight polyol (a)]

[0088] There are no particular restrictions on the manufacturing method of the high molecular weight polyol (a), and it can be manufactured using the same method as the known method of polycondensation of polyester polyol.

[0089] For example, branched polyols (a1) and polycarboxylic acids with 7 to 11 carbon atoms (a2) are added in a given ratio to carry out esterification or transesterification reactions, and the resulting reaction products are further subjected to polycondensation reactions at high temperature and vacuum in the presence of a polycondensation catalyst, thereby manufacturing the product.

[0090] It should be noted that, as the polycondensation catalyst used in the manufacture of high molecular weight polyols (a), known catalysts can be used, such as titanium compounds such as titanium tetraethanol, titanium tetraethanol, titanium tetra-n-propoxide, titanium tetraisopropoxide, and titanium tetrabutoxide; tin compounds such as di-n-butyltin oxide, di-n-butyltin dilaurate, and di-n-butyltin diacetate; and combinations of acetates of magnesium, calcium, zinc, etc. with antimony oxide or the above-mentioned titanium compounds.

[0091] The total amount of these polycondensation catalysts relative to the branched polyol (a1) and the polycarboxylic acid with 7 to 11 carbon atoms (a2) is preferably 5 to 500 ppm by mass.

[0092] <Structural Unit (B)>

[0093] The structural unit (B) is derived from the polyisocyanate (b). In addition, the structural unit (B) in the above-mentioned TPU mainly forms hard segments together with the structural unit (C) described later.

[0094] (Polyisocyanate (b))

[0095] As a polyisocyanate (b), a polyisocyanate used in the manufacture of conventional thermoplastic polyurethanes can be used.

[0096] From the viewpoint of the melt viscosity of the obtained TPU, the number of isocyanate groups in each molecule of the polyisocyanate (b) is preferably 2 to 10, more preferably 2 to 5, even more preferably 2 to 4, even more preferably 2 to 3, and even more preferably 2. That is, the polyisocyanate (b) is more preferably diisocyanate or triisocyanate, and even more preferably diisocyanate.

[0097] Furthermore, organic diisocyanates are preferred as the aforementioned diisocyanates. The term "organic diisocyanate" refers to at least one selected from aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates.

[0098] Examples of the aforementioned polyisocyanates (b) include, for example, ethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dodecanethylene diisocyanate, isophorone diisocyanate, isopropylidene bis(4-cyclohexyl)isocyanate, 1,3-bis(isocyanomethyl)cyclohexane, cyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, lysine diisocyanate, hexanoate (2,6-diisocyanomethyl) ester, fumarate bis(2-isocyanoethyl) ester, bis(2-isocyanoethyl) carbonate, and 2-isocyanoethyl-2,6-diisocyanohexanoate. Aliphatic or alicyclic diisocyanates such as cyclohexane diisocyanate, methylcyclohexane diisocyanate, and bis(2-isocyanoethyl)-4-cyclohexene; aromatic diisocyanates such as 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (abbreviated as MDI), 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophenyl diisocyanate, terephthalene diisocyanate, isophenylmethylene diisocyanate, terephthalene diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diisocyanobiphenyl, 3,3'-dimethyl-4,4'-diisocyanobiphenyl, 3,3'-dimethyl-4,4'-diisocyanodiphenylmethane, chlorophenyl-2,4-diisocyanate, and tetramethylphenylmethylene diisocyanate; etc. They can be used individually or in combination of two or more.

[0099] From the viewpoint of availability, the polyisocyanate (b) described above is preferably selected from at least one of hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,3-bis(isocyanomethyl)cyclohexane, 1,5-naphthalene diisocyanate, isophthalimethylene diisocyanate, and 4,4'-diphenylmethane diisocyanate (MDI). From the viewpoint of good reactivity, the polyisocyanate (b) described above is more preferably selected from at least one of 1,5-naphthalene diisocyanate, isophthalimethylene diisocyanate, and 4,4'-diphenylmethane diisocyanate (MDI), and even more preferably 4,4'-diphenylmethane diisocyanate (MDI).

[0100] <Structural Unit (C)>

[0101] The structural unit (C) originates from the chain extender (c). Furthermore, although there are no particular restrictions, as mentioned earlier, units formed from isocyanates and chain extenders are generally considered to be the main components of hard segments. Therefore, structural unit (C) in the aforementioned TPU primarily constitutes hard segments together with structural unit (B).

[0102] (Chain extender (c))

[0103] As the chain extender (c) that forms the structural unit (C), any type of chain extender conventionally used in the manufacture of thermoplastic polyurethanes can be used. Specifically, a low molecular weight compound having two or more active hydrogen atoms in its molecule that can react with isocyanate groups is preferred; a compound having two or more active hydrogen atoms in its molecule that can react with isocyanate groups and a molecular weight of less than 500 is more preferred. The molecular weight is further preferably 450 or less, and even more preferably 400 or less.

[0104] Examples of chain extenders (c) include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentanediol, 1,6-hexanediol, 2,5-dimethyl-2,5-hexanediol, 3-methyl-1,5-pentanediol, 1,4-bis(β-hydroxyethoxy)benzene, 1,4-cyclohexanediol, cyclohexanediol (e.g., 1,4-cyclohexanediol), and bis(β-hydroxyethyl)-p-benzene. Dimethyl esters, 1,9-nonanediol, isophenylenediol, terephthalic acid diethanolamine, triethylene glycol, and other diols; ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 3-methylpentamethylenediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 1,2-diaminopropane, 1,3-diaminopropane, hydrazine, xylylenediamine, isophorone diamine, piperazine, o-phenylenediamine, m-phenylenediamine, terephthalic acid diamine, etc. Amines, toluenediamine, xylenediamine, adipic acid dihydrazide, isophthalic acid dihydrazide, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-methylene-bis(2-chloroaniline), 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino Diphenyl sulfide, 2,6-diaminotoluene, 2,4-diaminochlorobenzene, 1,2-diaminoanthraquinone, 1,4-diaminoanthraquinone, 3,3'-diaminobenzophenone, 3,4-diaminobenzophenone, 4,4'-diaminobenzophenone, 4,4'-diaminobibenzyl, 2,2'-diamino-1,1'-binaphthyl, 1,3-bis(4-aminophenoxy)alkanes, 1,4-bis(4-aminophenoxy)alkanes, 1,5-bis(4-aminophenoxy)alkanes, etc., 1,n-bis(4-aminophenoxy)alkanes (n is 3-10), 1,2-bis[2-(4-aminophenoxy)ethoxy]ethane, 9,9-bis(4-aminophenyl)fluorene, 4,4'-diaminobenzoylaniline, etc., diamines; etc.They can be used individually or in combination of two or more.

[0105] Of the above, diols are preferred as chain extenders (c), and more preferably diols with a molecular weight of less than 500. The molecular weight of the diols is further preferably 450 or less, and even more preferably 400 or less.

[0106] From the viewpoint of availability and reactivity, the diol with a molecular weight of less than 500 is preferably selected from at least one of ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and 3-methyl-1,5-pentanediol; more preferably, it is selected from at least one of ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, and 3-methyl-1,5-pentanediol; even more preferably, it is selected from at least one of ethylene glycol, 1,3-propanediol, and 1,4-butanediol; and even more preferably, it is selected from at least one of ethylene glycol and 1,4-butanediol.

[0107] Here, the molecular weight of the chain extender (c) is a value obtained by summing the atomic weights of the elements constituting the compound. For example, if the chain extender (c) is the diol, it can also be calculated as the sum of the atomic weights of the elements constituting the molecular formula of the diol.

[0108] In addition, the molecular weight of the chain extender (c) can also be determined by gas chromatography-mass spectrometry (GC-MS).

[0109] <Other structural units (U)>

[0110] Without hindering the purpose and effect of the present invention, the above-mentioned TPU may further include other structural units (U) in addition to including structural units (A), (B) and (C).

[0111] Other structural units (U) can be exemplified by structural units derived from polycarbonate, polyether, polyurea, etc.

[0112] Furthermore, provided that the purpose and effects of the present invention are not impaired, the raw materials constituting the structural units (A), (B), and (C) of the TPU and other structural units (U) may also be manufactured from petroleum-derived raw materials, or from plant-derived raw materials. Alternatively, these raw materials may also be manufactured using a mass-balanced method.

[0113] For example, 3-methyl-1,5-pentanediol, which is most preferably used as a branched polyol (a1), can also be synthesized as follows: starting from petroleum-derived isobutylene, it undergoes an olefin reaction, a carbonylation reaction, and then a hydrogenation reaction. Alternatively, 3-methyl-1,5-pentanediol can also be synthesized by hydrogenation of 3-methyl-2-penten-1,5-diol and its isomers obtained through the olefin reaction of isobutylene. It should be noted that, for example, isobutylene can be not only petroleum-derived but can also be isobutylene obtained by dehydration of 2-methyl-1-propanol obtained through the fermentation of plant-derived sugars. Furthermore, 3-methyl-1,5-pentanediol can also be synthesized from mevalonate lactone obtained through the fermentation of plant-derived sugars, by sequentially subjecting mevalonate lactone to a dehydration reaction, an olefin hydrogenation reaction, and a lactone hydrogenation reaction. Alternatively, mevalonate lactone can be synthesized by sequentially subjecting it to lactone hydrogenation, dehydration, and olefin hydrogenation. Sebacic acid, preferably used as a polycarboxylic acid (a2), can be synthesized from plant-derived castor oil via an alkali fusion method.

[0114] <Content of each structural unit>

[0115] (Content of structural unit (A))

[0116] The aforementioned TPU contains 50 to 90% by mass of structural unit (A) in 100% by mass of all structural units. If the content of structural unit (A) is 50% by mass or more, a TPU with a suitable low hardness range can be synthesized. Furthermore, if the content of structural unit (A) is 90% by mass or less, a TPU with good mechanical properties can be synthesized. From the same viewpoint, the content of structural unit (A) in 100% by mass of all structural units of the aforementioned TPU is preferably 60 to 90% by mass, more preferably 65 to 90% by mass, further preferably 70 to 90% by mass, and even more preferably 75 to 90% by mass.

[0117] (Content of structural unit (B))

[0118] The aforementioned TPU contains 8 to 45% by mass of structural unit (B) in 100% by mass of all structural units. If the content of structural unit (B) is 8% by mass or more, a TPU with good mechanical properties can be synthesized. Furthermore, if the content of structural unit (B) is 45% by mass or less, a TPU with a suitable low hardness range can be synthesized. From the same viewpoint, the content of structural unit (B) in 100% by mass of all structural units of the aforementioned TPU is preferably 8 to 38% by mass, more preferably 8 to 33% by mass, even more preferably 8 to 28% by mass, and from the viewpoint of being able to synthesize a TPU with good mechanical properties and a lower hardness range, it is even more preferably 8 to 23% by mass.

[0119] (Content of structural unit (C))

[0120] The aforementioned TPU contains 2 to 10% by mass of structural unit (C) in 100% by mass of all structural units. If the content of structural unit (C) is 2% by mass or more, a TPU with good mechanical properties can be synthesized. Furthermore, if the content of structural unit (C) is 8% by mass or less, a TPU with a suitable low hardness range can be synthesized. From the same viewpoint, the content of structural unit (C) in 100% by mass of all structural units of the aforementioned TPU is preferably 2 to 8% by mass; more preferably 2 to 6% by mass; further preferably 2 to 5% by mass; and even more preferably 3 to 4% by mass.

[0121] (Total content of structural unit (A), structural unit (B) and structural unit (C))

[0122] Of the total 100% by mass of all structural units in the aforementioned TPU, the total content of structural unit (A), structural unit (B), and structural unit (C) is 70-100% by mass, preferably 75-100% by mass, more preferably 80-100% by mass, even more preferably 86-100% by mass, even more preferably 90-100% by mass, even more preferably 95-100% by mass, and may also be 100% by mass.

[0123] Here, regarding the content of each of the aforementioned structural units (A), (B), and (C), each content can be selected independently. However, it is understood that when combining the selected contents, combinations where the total content of structural units (A), (B), and (C) is greater than 100% by mass are not included. That is, the content of each of structural units (A), (B), and (C) is a combination where the total content of structural units (A), (B), and (C) is not greater than 100% by mass.

[0124] In this specification, the content of each structural unit of the TPU described above can be calculated based on the amount of the raw material compounds forming each structural unit. Alternatively, the content of the obtained TPU can also be calculated based on... 1 The result is determined by H-NMR measurements. In this case, if necessary, it can also be obtained using... 13 After confirming the structural units constituting the TPU through analyses such as C-NMR and GC-MS, the TPU was further analyzed using... 1 The content of each structural unit is determined by H-NMR measurement.

[0125] <Manufacturing Method of Thermoplastic Polyurethane>

[0126] As a method for manufacturing the aforementioned thermoplastic polyurethane, an example is given by reacting at least 50-90% by mass of a high molecular weight polyol (a) having terminal hydroxyl groups, 8-45% by mass of a polyisocyanate (b), and 2-10% by mass of a chain extender (c) in 100% by mass of the total raw material components of the thermoplastic polyurethane to obtain the thermoplastic polyurethane, wherein the aforementioned high molecular weight polyol (a) is a thermoplastic polyurethane containing structural units derived from branched polyols (a1) and polycarboxylic acids (a2) having 7-11 carbon atoms and having a number average molecular weight of 500 or more.

[0127] In addition, in the above-mentioned TPU manufacturing method, catalyst (d) is preferably used.

[0128] The thermoplastic polyurethane obtained by this manufacturing method is the same as the thermoplastic polyurethane described in the section on thermoplastic polyurethane as an embodiment of the present invention, and its preferred embodiment is also the same.

[0129] As for the manufacturing method of the aforementioned TPU, there are no particular limitations as long as the TPU can be obtained by combining the aforementioned raw materials in the aforementioned amounts. For example, it can be obtained by polymerization using a known prepolymer method or a one-step urethane esterification reaction. It is generally believed that, compared with the one-step method, the prepolymer method makes it easier for the structural units (C) derived from the chain extender (c) in the molecular chain to exhibit a regular configuration, thereby improving the dispersion of the structural units (C) in the molecular chain. Therefore, it is believed that TPU obtained by the prepolymer method exhibits excellent phase separation between soft and hard segments. However, it is difficult for those skilled in the art to perform chemical analysis on the dispersion of the structural units (C) in the molecular chain. In addition, although qualitative analysis of phase separation based on small-angle X-ray diffraction and the like can be performed, it is difficult to quantitatively analyze the magnitude of phase separation.

[0130] Alternatively, solution polymerization can be carried out in a reactive inert solvent, and melt polymerization can also be carried out under solvent-free conditions. More specifically, examples of melt polymerization include methods that produce the product by melt polymerization of the aforementioned components in a given ratio under substantially solvent-free conditions while simultaneously using a single-screw or multi-screw extruder (continuous melt polymerization), and methods that produce the product by melt polymerization of the product in a batch reactor under weakly mixed or unmixed conditions (batch melt polymerization).

[0131] Here, solution polymerization exhibits superior phase separation compared to melt polymerization, and batch melt polymerization demonstrates superior phase separation compared to continuous melt polymerization. This can be attributed to the fact that the phase separation of the polymer, which is not affected by mixing during polymerization, readily separates into soft and hard segments.

[0132] As one method for manufacturing the aforementioned TPU, a prepolymer method can be suitably used, in which a polymeric polyol (a) is reacted with a polyisocyanate (b) to obtain an isocyanate-terminated prepolymer, and a chain extender (c) is then reacted with it. Furthermore, in this prepolymer method, a catalyst (d) is preferably used when reacting the chain extender (c) with the isocyanate-terminated prepolymer.

[0133] (catalyst (d))

[0134] As catalyst (d), urethane esterification reaction catalysts that have been used in the manufacture of thermoplastic polyurethanes can be used. Examples of such urethane esterification reaction catalysts include organotin compounds, organozinc compounds, organobismuth compounds, organotitanium compounds, organozirconium compounds, and amine compounds. Among these, from the viewpoint of reactivity, at least one of amine compounds, organotin compounds, and organobismuth compounds is preferred, and from the viewpoint of operability, amine compounds are more preferred.

[0135] Tertiary amine compounds are preferred as the aforementioned amine compounds. Examples of tertiary amine compounds include triethylenediamine, N,N,N',N'-tetramethyl-1,6-hexanediamine, bis(2-dimethylaminoethyl) ether, N,N,N',N”,N”-pentamethyldiethylenetriamine, N-methylmorpholine, N-ethylmorpholine, N,N-dimethylethanolamine, 1-methylimidazole, 1,2-dimethylimidazole, N,N'-dimethylpiperazine, 1,4-diazabicyclo[2,2,2]octane, 1,8-diazabicyclo[5,4,0]undecene-7, 1,5-diazabicyclo[4,3,0]nonene-5, 1,8-diazabicyclo[5,4,0]decene-7, and 1,4-diazabicyclo[3,3,3]octene-4. They can be used alone or in combination of two or more.

[0136] From the viewpoint of ensuring an appropriate polymerization rate, the amount of catalyst (d) used is preferably 0.1 to 1000 ppm by mass relative to the total amount of polymeric polyol (a), polyisocyanate (b), and chain extender (c), more preferably 1 to 800 ppm by mass, and even more preferably 10 to 500 ppm by mass.

[0137] <Various Properties of Thermoplastic Polyurethane>

[0138] (Hardness A of hardness tester)

[0139] From the viewpoint of achieving better softness, the hardness of the TPU measured according to JIS K 7215-1986 using a hardness tester A is preferably HDA 95 or less. From the same viewpoint, the hardness of the aforementioned hardness tester A is more preferably 90 or less, further preferably 80 or less, even more preferably HDA 75 or less, and even more preferably HDA 70 or less.

[0140] Furthermore, from the viewpoint of formability, an HDA of 30 or higher is preferred. From the same viewpoint, the hardness of the aforementioned hardness tester A is more preferably HDA 50 or higher, and even more preferably HDA 60 or higher.

[0141] In other words, the hardness of the hardness tester A is preferably HDA30-95, more preferably HDA30-90, even more preferably HDA30-80, even more preferably HDA50-75, and even more preferably HDA60-70.

[0142] Furthermore, if the phase separation of the TPU is advanced through the curing process described later, the hardness of the hardness tester A will increase.

[0143] Here, as a method for reducing the hardness of thermoplastic polyurethane, for example, there is a known method of adding a plasticizer to a high-hardness thermoplastic polyurethane to create a low-hardness thermoplastic polyurethane composition.

[0144] On the other hand, as described later, the TPU described above, as an aspect of the present invention, can achieve the aforementioned low hardness substantially without containing plasticizers. That is, the TPU described above can also be suitably used as a so-called plasticizer-free low-hardness thermoplastic polyurethane. If it is a plasticizer-free low-hardness thermoplastic polyurethane, it is preferable from the viewpoint of preventing the plasticizer from leaching out of the thermoplastic polyurethane composition and blooming.

[0145] (Crystallization temperature)

[0146] When the aforementioned TPU has a crystallization temperature, from the viewpoint of superior low-temperature characteristics, the crystallization temperature is preferably below -15°C, more preferably below -30°C, and even more preferably below -40°C. Furthermore, there are no particular limitations on the lower limit of the aforementioned crystallization temperature.

[0147] Specifically, the crystallization temperature values ​​mentioned above are values ​​determined using the methods described in the examples.

[0148] Furthermore, it is preferable that the crystallization temperature is not observed when the crystallization temperature is measured using the method described in the examples, as in the aforementioned TPU.

[0149] It should be noted that, generally speaking, the crystallization temperature does not change with the degree of phase separation.

[0150] (Complex elastic modulus E at 150℃) The complex elastic modulus E relative to 25℃ ratio)

[0151] Regarding the aforementioned TPU, from the perspective of superior heat resistance, the complex modulus of elasticity E at 150°C of the sheet produced by injection molding (the thermoplastic polyurethane sheet after injection molding) is... The complex elastic modulus E relative to 25℃ The ratio of [E] (150℃) / E (25°C)] Preferably 0.15 or more, more preferably 0.17 or more, even more preferably 0.18 or more, even more preferably 0.20 or more, even more preferably 0.25 or more, even more preferably 0.30 or more.

[0152] Furthermore, regarding the above ratio [E] of the sheet produced by injection molding (150℃) / E The upper limit of (25°C) is preferably 1.20 or less, more preferably 1.15 or less, even more preferably 1.10 or less, even more preferably 1.08 or less, even more preferably 1.05 or less, and even more preferably 1.03 or less, from the viewpoint of better heat resistance.

[0153] As one method of producing the aforementioned TPU, from the viewpoint of superior heat resistance, the sheet manufactured by injection molding has the above-mentioned ratio [E]. (150℃) / E (25℃)] Preferably 0.15 to 1.20, more preferably 0.17 to 1.15, even more preferably 0.18 to 1.10, even more preferably 0.20 to 1.08, even more preferably 0.25 to 1.05, even more preferably 0.30 to 1.03.

[0154] If the above ratio [E] (150℃) / E (25℃) means that the difference between the complex modulus of elasticity at 25℃ and the complex modulus of elasticity at 150℃ is small, and the changes in the physical properties of thermoplastic polyurethane under low temperature and high temperature environments are also less. That is, it means that the heat resistance of thermoplastic polyurethane is better.

[0155] The above ratio of the sheet produced by injection molding [E] (150℃) / E Specifically, the value of (25°C) is the value determined using the method described in the examples.

[0156] Here, if the phase separability is low, then the above ratio [E] (150℃) / E (25℃)] is a low value. If phase separation is promoted due to the aging process described later, then the above ratio [E] (150℃) / E (25℃) The temperature increases.

[0157] In addition, the sheets produced by injection molding mentioned above can, for example, be sheets conforming to item 3.3 of JIS K 7311-1995 standard.

[0158] Furthermore, since the sheets used in the above evaluation need to be evaluated using sheets without molding defects, the injection molding conditions are preferably set appropriately to prevent molding defects from occurring in the resulting sheets. For example, it is preferable to set the molding conditions in a way that allows the TPU to be introduced into all surfaces of the mold without causing molding defects such as shrinkage of the molded body. That is, since it is necessary to use sheets without molding defects for evaluation, it is preferable to appropriately set the injection molding conditions according to the characteristics of the TPU used.

[0159] Therefore, when conducting comparisons based on the above evaluations, it is best to evaluate the pieces under the same injection molding conditions as much as possible. However, it is first necessary to obtain pieces without molding defects (since pieces with inherent molding defects cannot be tested), so it is sometimes difficult to standardize all molding conditions. Thus, sometimes it is necessary to obtain the necessary pieces for evaluation under conditions that are as close as possible to the required range and without molding defects.

[0160] As mentioned above, the injection molding conditions are preferably set appropriately according to the composition of the TPU used. For example, as one method of injection conditions, an injection molding machine is used to perform melt mixing at a peak barrel temperature of 130 to 280°C, and injection molding is performed at an injection pressure of 1 to 200 MPa, a mold holding time of 3 seconds to 10 minutes, and a mold temperature of 0 to 70°C. It is also possible to obtain sheets according to item 3.3 of JIS K 7311-1995 standard while appropriately adjusting the conditions within this range to avoid molding defects.

[0161] Furthermore, regarding the aforementioned TPU, from the perspective of superior heat resistance, the complex elastic modulus E at 150°C after polymerization and curing but before injection molding is... The complex elastic modulus E relative to 25℃ The ratio of [E] (150℃) / E (25°C)] Preferably 0.67 or more, more preferably 0.68 or more, even more preferably 0.70 or more, even more preferably 0.75 or more, even more preferably 0.85 or more, even more preferably 0.95 or more.

[0162] In addition, regarding the above ratio [E] after polymerization and maturation and before injection molding (150℃) / E The upper limit of (25°C) is preferably 1.20 or less, more preferably 1.15 or less, even more preferably 1.10 or less, even more preferably 1.08 or less, even more preferably 1.05 or less, and even more preferably 1.03 or less, from the viewpoint of better heat resistance.

[0163] As one approach to the aforementioned TPU, from the viewpoint of superior heat resistance, the ratio of [E] after polymerization and curing, before injection molding... (150℃) / E (25℃) The preferred value is 0.67 to 1.20, more preferably 0.68 to 1.15, even more preferably 0.70 to 1.10, even more preferably 0.75 to 1.08, even more preferably 0.85 to 1.05, and even more preferably 0.95 to 1.03.

[0164] The above-mentioned ratio [E] after polymerization and curing of TPU and before injection molding (150℃) / E Specifically, the value of (25°C) is the value determined using the method described in the examples.

[0165] (weight-average molecular weight)

[0166] The weight-average molecular weight (Mw) of the above-mentioned TPU is preferably 10,000 to 500,000, more preferably 20,000 to 250,000, and even more preferably 50,000 to 200,000.

[0167] If the weight-average molecular weight (Mw) of the above-mentioned TPU is 10,000 or more, it is preferred from the viewpoint of obtaining better mechanical properties and durability; if it is 500,000 or less, it is preferred from the viewpoint of obtaining better formability.

[0168] The number-average molecular weight (Mw) of the aforementioned TPU can be determined using gel permeation chromatography (GPC) via conversion to standard poly(methyl methacrylate). For example, it can be determined using the method shown below.

[0169] <GPC Determination Conditions>

[0170] Device: GPC device "HLC-8220" manufactured by TOSOH Co., Ltd.

[0171] Separation column: "TSKgel AWM-M (column diameter = 6.0mm, column length = 15cm)" manufactured by TOSOH Corporation (two columns are used in series).

[0172] Eluent: N,N-dimethylformamide with 10 mM lithium bromide dissolved in it.

[0173] Elution flow rate: 1.0 mL / min

[0174] Column temperature: 40℃

[0175] Detection method: Differential refractive index (RI)

[0176] Injection volume: 10 μL

[0177] Concentration: 1 mg / 1 mL (TPU / N,N-dimethylformamide)

[0178] Standard material: Poly(methyl methacrylate)

[0179] [Thermoplastic polyurethane composition]

[0180] As one aspect of the invention, a thermoplastic polyurethane composition comprising the aforementioned TPU can be provided. Furthermore, other components may be incorporated into the aforementioned TPU as needed. That is, in one aspect of the invention, a thermoplastic polyurethane composition comprising the aforementioned TPU and other components can be provided.

[0181] The content of TPU in the above-described thermoplastic polyurethane composition can be appropriately adjusted according to the intended use of the thermoplastic polyurethane composition. As one embodiment of the above-described thermoplastic polyurethane composition, the content of TPU is preferably 50% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and even more preferably 95% by mass or more in 100% by mass of the thermoplastic polyurethane composition. Furthermore, the upper limit of the content of TPU in the above-described thermoplastic polyurethane composition is not particularly limited; however, for example, it can be 99.99% by mass.

[0182] Other components mentioned above include plasticizers, crosslinking agents, fillers, crosslinking accelerators, crosslinking aids, softeners, tackifiers, anti-aging agents, foaming agents, processing aids, adhesion promoters, inorganic fillers, organic fillers, crystallizing nucleating agents, heat stabilizers, weather stabilizers, antistatic agents, colorants, lubricants, flame retardants, flame retardant additives (antimony oxide, etc.), bloom inhibitors, release agents, thickeners, antioxidants, conductive agents, and hydrolysis inhibitors (carbodiimide, etc.). Additionally, polymers other than the TPU described in one aspect of the present invention can be cited. Examples of polymers other than the TPU described in one aspect of the present invention include TPUs other than the TPU described in one aspect of the present invention, thermosetting polyurethanes, polyvinyl chloride, polymethyl methacrylates, and thermoplastic polyester elastomers.

[0183] In the above-described thermoplastic polyurethane composition, the total content of the other components is preferably 50% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less. Furthermore, the lower limit of the total content of the other components in the above-described thermoplastic polyurethane composition is not particularly limited; however, it can be, for example, 0.01% by mass.

[0184] Furthermore, the aforementioned TPU can achieve low hardness even without plasticizers. Therefore, from the viewpoint of preventing plasticizer exudation and blooming from the thermoplastic polyurethane composition, the thermoplastic polyurethane composition preferably contains substantially no plasticizers. Specifically, "substantially no plasticizers" means that in 100% by mass of the aforementioned thermoplastic polyurethane composition, the plasticizer content is 1% by mass or less, preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.01% by mass or less. Additionally, as an embodiment of the present invention, the thermoplastic polyurethane composition may also have a plasticizer content of 0% by mass in 100% by mass of the aforementioned thermoplastic polyurethane composition. In other words, in the thermoplastic polyurethane composition as an embodiment of the present invention, the plasticizer content in 100% by mass of the aforementioned thermoplastic polyurethane composition is 0 to 1% by mass, preferably 0 to 0.1% by mass, more preferably 0 to 0.05% by mass, even more preferably 0 to 0.01% by mass, and may also be 0% by mass.

[0185] The other components mentioned above can be appropriately incorporated during or after the polymerization of the TPU. Alternatively, for example, they can be pre-incorporated into the raw material components (e.g., high molecular weight polyol (a)) before the polymerization of the TPU.

[0186] [molded body]

[0187] The molded body, as one aspect of the present invention, comprises the aforementioned TPU.

[0188] Examples of the aforementioned molded bodies include, for instance, automotive parts such as bumpers, side moldings, taillight seals, snow chains, ball joint seals, constant velocity joint covers, bellows, spring cover materials, ABS cables, ABS cable plugs, dashboard covers, gear shift levers, consoles, door seals, sheets, and handles; industrial parts such as belts, conduits, hoses, wire sheathing materials, cable sheathing materials, fire hoses, gears, casters, pads, and wind turbines; various sheets, air cushions, synthetic leather, and protective films; everyday items such as shoe soles, shoe cushioning materials, watch straps, camera grips, animal ear tags, smartphone cases, tablet cases, keyboard covers, and decorative items; medical products such as heart valves, bypass devices, artificial ventricles, dialysis catheters, films, connectors, fluid guides, medical catheters, and pacemaker insulators; building materials such as interior and exterior decorative materials; and sporting goods such as skis and rackets.

[0189] Among them, low-hardness thermoplastic polyurethane is particularly suitable for use in dialysis catheters, fluid catheters, medical catheters, shoe soles, shoe cushioning materials, resins, and protective films for metals.

[0190] Furthermore, due to its excellent heat resistance, the aforementioned TPU is also suitable for applications requiring high-temperature environments, such as automotive parts and industrial components. Additionally, its excellent low-temperature properties make it suitable for applications involving thermoplastic polyurethane in low-temperature environments, such as conveyor belts for food processing at low temperatures, or applications in cold regions.

[0191] There are no particular limitations on the forming method for the above-mentioned molded articles. For example, the following forming methods can be used: directly cutting or slicing the TPU or thermoplastic polyurethane composition that has just been polymerized; casting or impregnation by dissolving the TPU or thermoplastic polyurethane composition in a solvent to form a homogeneous solution and then sheeting or filmizing it; and various forming methods such as extrusion molding, injection molding, calendering, injection molding, blow molding, blow forming, foaming molding, rotational molding, and oblique extrusion molding, after heating and mixing the TPU or thermoplastic polyurethane composition.

[0192] Furthermore, the molded article described above may be a molded article formed solely from the aforementioned TPU or thermoplastic polyurethane composition, or it may be a composite molded article of the aforementioned TPU or thermoplastic polyurethane composition with other materials (e.g., a laminated structure of the aforementioned TPU or thermoplastic polyurethane composition with other materials). There are no particular limitations on the composite molded article; however, it can be formed by insert molding, co-extrusion molding, etc.

[0193] The TPU, thermoplastic polyurethane composition, or molded article described above, immediately after polymerization, can be used directly for various applications. For the purpose of improving or stabilizing physical properties due to phase separation, they can also be used after a curing process. The time required for the curing process is not particularly limited as long as the above objectives are achieved. For example, from the viewpoint of easily achieving the above objectives, it is preferably 10 minutes or more, more preferably 1 hour or more, further preferably 2 hours or more, and even more preferably 3 hours or more. Furthermore, from the viewpoint of productivity, it is preferably less than 3 months, more preferably less than 1 month, further preferably less than 1 week, and even more preferably less than 1 day. During the curing process, since the higher the curing temperature, the easier it is to achieve the above objectives, the temperature during the curing process is preferably 30°C or more, more preferably 40°C or more, and even more preferably 50°C or more. Furthermore, from the viewpoint of suppressing thermal deformation of the resulting molded article, the above temperature is preferably 150°C or less, more preferably 140°C or less, and even more preferably 130°C or less. The temperature can also be changed during the curing process. When the temperature is changed during the curing process, from the viewpoint of suppressing thermal deformation of the resulting molded body, it is preferable to shorten the time exposed to higher temperatures.

[0194] Example

[0195] The following describes the present embodiment in further detail with reference to examples; however, the present embodiment is not limited to these examples.

[0196] The physical properties of the raw materials and thermoplastic polyurethanes in the examples and comparative examples were determined or evaluated using the following methods.

[0197] (1) Number-average molecular weight

[0198] The number-average molecular weight of the polyols (a) used in the examples and comparative examples was calculated based on the hydroxyl value of the polyols (a) using the following methods.

[0199] • Number average molecular weight (Mn) of high molecular weight polyol (a) = molecular weight of KOH (56.1) × number of functional groups × 1000 / hydroxyl value (mgKOH / g)

[0200] It should be noted that the hydroxyl value was determined using Method B (phthalylation method) as described in JIS K1557-1:2007.

[0201] (2) Hardness A of the hardness tester (HDA)

[0202] The hardness A (HDA) of thermoplastic polyurethane is measured using a type A hardness tester in accordance with JIS K 7215-1986.

[0203] (3) Low-temperature characteristics (determination of crystallization temperature (Tc))

[0204] The crystallization temperature (Tc) of thermoplastic polyurethane was determined using differential scanning calorimetry (DSC) under the following conditions, with the temperature of the peak of the exothermic peak observed during the third cooling process described below being taken as the crystallization temperature.

[0205] The lower the crystallization temperature, the better the low-temperature properties of the thermoplastic polyurethane. Furthermore, if the crystallization temperature is not observed within the measurement temperature range of this embodiment, the low-temperature properties of the thermoplastic polyurethane are also excellent.

[0206] <DSC Measurement Conditions>

[0207] • Measuring instrument: TA Instruments "DSC 25"

[0208] • Heating rate: +10℃ / minute

[0209] Cooling rate: -10℃ / minute

[0210] Nitrogen flow rate: 100 mL / min

[0211] • Temperature profile (perform the following steps 1 through 3 consecutively).

[0212] First time: Cool from 30℃ to -100℃ and hold at -100℃ for 5 minutes.

[0213] Second time: Raise the temperature from -100℃ to 200℃ and hold at 200℃ for 5 minutes.

[0214] Third time: Cool down from 200℃ to -100℃ and hold at -100℃ for 5 minutes.

[0215] (4) Heat resistance

[0216] The heat resistance of thermoplastic polyurethane is determined by calculating the complex elastic modulus E at 150℃. The complex elastic modulus E relative to 25℃ The ratio of [E] (150℃) / E (25℃) is used for evaluation.

[0217] Regarding the complex elastic modulus E at various temperatures Test pieces (size: 5mm width × 15mm length × 2mm thickness) were prepared using thermoplastic polyurethane sheets (two types before and after injection molding) prepared by the punching examples and comparative examples, and the results were confirmed by DMA (dynamic viscoelasticity) determination based on the following conditions.

[0218] <DDMA Measurement Conditions>

[0219] • Measuring instrument: NETZSCH "DMA 242 E Artemis"

[0220] • Temperature range: from -80℃ to 150℃.

[0221] • Heating rate: +3℃ / minute

[0222] • Frequency: 10Hz

[0223] • Deformation mode: Stretch mode

[0224] The polymeric polyols or thermoplastic polyurethanes used in the examples and comparative examples were manufactured using the following method. The components (a) to (d) and the polyols other than polymeric polyol (a) are shown below.

[0225] <Polyols (a)>

[0226] • Polyol 1 (abbreviated as "PO1"): Manufactured by Kuraray Co., Ltd., product name "Kuraray POLYOL P-4050" (polymer of 3-methyl-1,5-pentanediol and sebacic acid (10 carbons), number average molecular weight 4000)

[0227] • Polyol 2 (abbreviated as "PO2"): Manufactured by Kuraray Co., Ltd., product name "KURARAY POLYOL P-6050" (polymer of 3-methyl-1,5-pentanediol and sebacic acid (10 carbons), number average molecular weight 6000)

[0228] • Polyol 3 (abbreviated as "PO3"): Manufactured by KURARAY Co., Ltd., product name "KURARAY POLYOL P-2050" (polymer of 3-methyl-1,5-pentanediol and sebacic acid (10 carbons), number average molecular weight 2000)

[0229] • Polyol 4 (PO4): A polymer of 1,3-propanediol, 3-methyl-1,5-pentanediol, and sebacic acid (10 carbon atoms), with a number average molecular weight of 3000.

[0230] • Polyol 5 (PO5): A polymer of 3-methyl-1,5-pentanediol and octanoic acid (8 carbons), with a number average molecular weight of 4000.

[0231] • Polyol 6 (PO6): Manufactured by KURARAY Co., Ltd., product name "KURARAY POLYOL P-3050" (polymer of 3-methyl-1,5-pentanediol and sebacic acid (10 carbon atoms), number average molecular weight 3000)

[0232] <Polyols other than high molecular weight polyols (a)>

[0233] • Polyol R1 (abbreviated as "PO-R1"): Manufactured by KURARAY Co., Ltd., product name "KURARAY POLYOL P-4010" (polymer of 3-methyl-1,5-pentanediol and adipic acid (6 carbons), number average molecular weight 4000)

[0234] • Polyol R2 (abbreviated as "PO-R2"): A polymer of 3-methyl-1,5-pentanediol and dodecanoic acid (12 carbon atoms), with a number average molecular weight of 4000.

[0235] • Polyol R3 (abbreviated as "PO-R3"): Manufactured by KURARAY Co., Ltd., product name "KURARAY POLYOL P-2010" (polymer of 3-methyl-1,5-pentanediol and adipic acid (carbon number 6), number average molecular weight 2000)

[0236] • Polymer polyol R4 (abbreviated as "PO-R4"): Manufactured by DAICEL Co., Ltd., product name "PLACCEL (registered trademark) PCL220N" (polycaprolactone diol, number average molecular weight 2000).

[0237] Polymer polyol 4, polymer polyol 5 and polymer polyol R2 are manufactured using the following method.

[0238] [Synthetic Example 1: Synthesis of Polyol 4]

[0239] 1,3-Propanediol (100 g), 3-methyl-1,5-pentanediol (156 g), and sebacic acid (256 g) were added to a reaction vessel. The mixture was heated to 160 °C under nitrogen purging with stirring. After confirming the acid value was below 30 mg KOH / g, the mixture was cooled to 150 °C. Subsequently, a 10 wt% toluene solution of tetraisopropyl titanate was added to achieve a titanium atom (Ti) ratio of 20 ppm to the final polymer polyol 4. The temperature was then raised to 180 °C. After confirming the target molecular weight was reached based on hydroxyl value determination, approximately 2 wt% water was added relative to the final polymer polyol 4 to deactivate the catalyst. The mixture was then heated at 100 °C for 2 hours. Afterward, the mixture was cooled to 50 °C, and the water content was confirmed to be below 200 ppm by reducing the pressure, yielding the aforementioned polymer polyol 4.

[0240] [Synthetic Example 2: Synthesis of Polyol 5]

[0241] 286 g of 3-methyl-1,5-pentanediol and 330 g of octanoic acid were added to a reaction vessel. The mixture was heated to 160 °C under nitrogen purging with stirring. After confirming the acid value was below 30 mg KOH / g, the mixture was cooled to 150 °C. Subsequently, a 10 wt% toluene solution of tetraisopropyl titanate was added to achieve a titanium atom (Ti) ratio of 20 ppm by mass relative to the final polymer polyol 5. The temperature was then raised to 180 °C. After confirming the target molecular weight was reached based on hydroxyl value determination, approximately 2 wt% water was added relative to the final polymer polyol 5 to deactivate the catalyst. The mixture was then heated at 100 °C for 2 hours. Afterward, the mixture was cooled to 50 °C, and the water content was confirmed to be below 200 ppm by mass through reduced pressure, yielding the aforementioned polymer polyol 5.

[0242] [Synthetic Example 3: Synthesis of Polyol R2]

[0243] 238 g of 3-methyl-1,5-pentanediol and 358 g of dodecanoic acid were added to a reaction vessel. The mixture was heated to 160 °C under nitrogen purging with stirring. After confirming the acid value was below 30 mg KOH / g, the mixture was cooled to 150 °C. Subsequently, a 10 wt% toluene solution of tetraisopropyl titanate was added to achieve a titanium atom (Ti) ratio of 20 ppm by mass relative to the final polymeric polyol R2. The temperature was then raised to 180 °C. After confirming the target molecular weight was reached based on hydroxyl value determination, approximately 2 wt% water was added relative to the final polymeric polyol R2 to deactivate the catalyst. The mixture was then heated at 100 °C for 2 hours. Afterward, the mixture was cooled to 50 °C, and the water content was confirmed to be below 200 ppm by mass through reduced pressure, yielding the aforementioned polymeric polyol R2.

[0244] <Polyisocyanates (b)>

[0245] 4,4'-Diphenylmethane diisocyanate (manufactured by TOSOH Corporation)

[0246] <Chain extender (c)>

[0247] 1,4-Butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0248] Ethylene glycol (manufactured by Kanto Chemical Co., Ltd.)

[0249] <Catalyst (d)>

[0250] 1,4-Diazabicyclo[2,2,2]octane (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0251] [Example 1]

[0252] Polyol 1 (795 g, 0.20 mol) was added to a reaction vessel and heated to 80°C. While stirring, 4,4'-diphenylmethane diisocyanate (174 g, 0.70 mol) was added, and the mixture was heated to 100°C and reacted for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.159 g) and ethylene glycol (31 g, 0.50 mol) at 40°C were added and stirred for 3 minutes to obtain the reactants.

[0253] The resulting reactants are cured at 80°C for 2 hours to form sheets. It should be noted that the term "curing" refers to the process of solidification after injection molding, where the reactants lose their fluidity due to the increasing molecular weight of the reactants. This is different from the curing process of thermosetting resins, which occurs through cross-linking reactions using cross-linking agents. The same applies to the following descriptions in this specification.

[0254] The obtained sheet material was stored at 125°C for 1 hour and then at 100°C for 12 hours in sequence to cure it, thus obtaining a thermoplastic polyurethane sheet before injection molding.

[0255] The obtained thermoplastic polyurethane sheet is then cut into strips. These strips are melt-blended using an injection molding machine "SE130EV" (manufactured by SUMITOMO Heavy Industries, Ltd.) at a peak barrel temperature of 200°C. Injection molding is then performed at an injection pressure of 50 MPa, a mold holding time of 10 seconds, and a mold temperature of 30°C, yielding a sheet conforming to item 3.3 of JIS K 7311-1995 (where the sheet dimensions are 100 mm in length × 100 mm in width × 2 mm in thickness). This sheet is then cured at 80°C for 6 hours to obtain the injection-molded thermoplastic polyurethane sheet.

[0256] [Example 2]

[0257] Polyol 1 (784 g, 0.20 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (172 g, 0.69 mol) was added, and the reaction was carried out at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.0784 g) and 1,4-butanediol (44 g, 0.49 mol) at 40 °C were further added, and the mixture was stirred for 3 minutes to obtain the reactants.

[0258] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to allow them to mature, resulting in thermoplastic polyurethane sheets before injection molding.

[0259] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0260] [Example 3]

[0261] Polyol 2 (853 g, 0.14 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (125 g, 0.50 mol) was added, and the reaction was carried out at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.170 g) and ethylene glycol (22 g, 0.35 mol) at 40 °C were further added, and the mixture was stirred for 3 minutes to obtain the reactants.

[0262] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to allow them to mature, resulting in thermoplastic polyurethane sheets before injection molding.

[0263] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0264] [Example 4]

[0265] Polyol 3 (772 g, 0.39 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (193 g, 0.77 mol) was added, and the reaction was carried out at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.0772 g) and 1,4-butanediol (35 g, 0.39 mol) at 40 °C were added, and the mixture was stirred for 3 minutes to obtain the reactants.

[0266] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to allow them to mature, resulting in thermoplastic polyurethane sheets before injection molding.

[0267] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0268] [Example 5]

[0269] Polyol 4 (763 g, 0.25 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (191 g, 0.76 mol) was added, and the reaction was carried out at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.0763 g) and 1,4-butanediol (46 g, 0.51 mol) at 40 °C were added and stirred for 3 minutes to obtain the reactants.

[0270] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to obtain thermoplastic polyurethane sheets before injection molding.

[0271] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0272] [Example 6]

[0273] Polyol 5 (784 g, 0.20 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (172 g, 0.69 mol) was added, and the mixture was reacted at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.0784 g) and 1,4-butanediol (44 g, 0.49 mol) at 40 °C were added, and the mixture was stirred for 3 minutes to obtain the reactants.

[0274] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to obtain thermoplastic polyurethane sheets before injection molding.

[0275] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0276] [Example 7]

[0277] Polyol 6 (651 g, 0.22 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (271 g, 1.08 mol) was added, and the mixture was reacted at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.0651 g) and 1,4-butanediol (78 g, 0.87 mol) at 40 °C were added, and the mixture was stirred for 3 minutes to obtain the reactants.

[0278] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to obtain thermoplastic polyurethane sheets before injection molding.

[0279] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0280] [Example 8]

[0281] Polyol 1 (653 g, 0.16 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (266 g, 1.06 mol) was added, and the mixture was reacted at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.0653 g) and 1,4-butanediol (81 g, 0.90 mol) at 40 °C were added, and the mixture was stirred for 3 minutes to obtain the reactants.

[0282] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to obtain thermoplastic polyurethane sheets before injection molding.

[0283] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0284] [Comparative Example 1]

[0285] Polyol R1 (795 g, 0.20 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (174 g, 0.70 mol) was added, and the reaction was carried out at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.159 g) and ethylene glycol (31 g, 0.50 mol) at 40 °C were added, and the mixture was stirred for 3 minutes to obtain the reactants.

[0286] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to allow them to mature, resulting in thermoplastic polyurethane sheets before injection molding.

[0287] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0288] [Comparative Example 2]

[0289] Polyol R2 (784 g, 0.20 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (172 g, 0.69 mol) was added, and the reaction was carried out at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.0784 g) and 1,4-butanediol (44 g, 0.49 mol) at 40 °C were added and stirred for 3 minutes to obtain the reactants.

[0290] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to allow them to mature, resulting in thermoplastic polyurethane sheets before injection molding.

[0291] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0292] [Comparative Example 3]

[0293] Polyol R2 (795 g, 0.20 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (174 g, 0.70 mol) was added, and the reaction was carried out at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.159 g) and ethylene glycol (31 g, 0.50 mol) at 40 °C were added, and the mixture was stirred for 3 minutes to obtain the reactants.

[0294] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to allow them to mature, resulting in thermoplastic polyurethane sheets before injection molding.

[0295] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0296] [Comparative Example 4]

[0297] Polyol R3 (611 g, 0.31 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (306 g, 1.22 mol) was added, and the reaction was carried out at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.0611 g) and 1,4-butanediol (83 g, 0.92 mol) at 40 °C were added, and the mixture was stirred for 3 minutes to obtain the reactants.

[0298] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to obtain thermoplastic polyurethane sheets before injection molding.

[0299] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0300] [Comparative Example 5]

[0301] Polyol R4 (611 g, 0.31 mol) was added to a reaction vessel and heated to 80 °C. While stirring, 4,4'-diphenylmethane diisocyanate (306 g, 1.22 mol) was added, and the reaction was carried out at 100 °C for 30 minutes. After stopping the heating of the reaction vessel, 1,4-diazabicyclo[2,2,2]octane (0.0611 g) and 1,4-butanediol (83 g, 0.92 mol) at 40 °C were added, and the mixture was stirred for 3 minutes to obtain the reactants.

[0302] The resulting reactants were cured at 80°C for 2 hours to form sheets. The resulting sheets were then stored at 125°C for 1 hour and at 100°C for 12 hours to obtain thermoplastic polyurethane sheets before injection molding.

[0303] Then, the same operation as in Example 1 was performed on the obtained thermoplastic polyurethane sheet before injection molding to obtain the thermoplastic polyurethane sheet after injection molding.

[0304]

[0305]

[0306] The compounds other than the high molecular weight polyols represented by the abbreviations in Tables 1 and 2 are shown below. The abbreviations for the high molecular weight polyols are as previously stated.

[0307] MDI: 4,4'-Diphenylmethane diisocyanate

[0308] EG: Ethylene glycol

[0309] BD: 1,4-Butanediol

[0310] DABCO: 1,4-diazabicyclo[2,2,2]octane

[0311] Based on the results in Tables 1 and 2, it was confirmed that the thermoplastic polyurethanes of Examples 1-8 comprise structural units (A) derived from a high molecular weight polyol (a) with terminal hydroxyl groups, structural units (B) derived from a polyisocyanate (b), and structural units (C) derived from a chain extender (c). The aforementioned high molecular weight polyol (a) comprises structural units derived from a branched polyol (a1) and a polycarboxylic acid (a2) with 7-11 carbon atoms, and has a number average molecular weight of 500 or higher.

[0312] Of the 100% by mass of all structural units in the above-mentioned thermoplastic polyurethane, 50-90% by mass of structural unit (A), 8-45% by mass of structural unit (B), and 2-10% by mass of structural unit (C) are included. Therefore, compared with the thermoplastic polyurethane of the comparative example shown in Table 1, it can achieve both good heat resistance and excellent low-temperature properties.

[0313] It is also known that the thermoplastic polyurethanes of Examples 1-8 can maintain a low hardness A even without plasticizers.

[0314] It was confirmed that the thermoplastic polyurethanes of Comparative Examples 1 and 4 had poorer heat resistance compared to the thermoplastic polyurethanes of the other examples. This can be attributed to the fact that in the thermoplastic polyurethanes of Comparative Examples 1 and 4, the structural units derived from polycarboxylic acids constituting the polymeric polyols were derived from polycarboxylic acids with 6 carbon atoms.

[0315] Furthermore, it was confirmed that the thermoplastic polyurethanes of Comparative Examples 2 and 3 exhibited poorer low-temperature properties compared to the thermoplastic polyurethanes of the various embodiments. This can be attributed to the fact that, in the thermoplastic polyurethanes of Comparative Examples 2 and 3, the structural units derived from polycarboxylic acids constituting the polymeric polyols are derived from polycarboxylic acids with 12 carbon atoms.

[0316] It was confirmed that the thermoplastic polyurethane of Comparative Example 5 had poorer heat resistance compared to the thermoplastic polyurethanes of the other examples. This can be attributed to the fact that, in the thermoplastic polyurethane of Comparative Example 5, the structural unit constituting the polymeric polyol is derived from caprolactone, which has 6 carbon atoms.

[0317] Industrial availability

[0318] As shown in the foregoing examples, the thermoplastic polyurethane, as an embodiment of the present invention, can achieve both good heat resistance and excellent low-temperature properties. Furthermore, the aforementioned TPU can achieve low hardness even without plasticizers.

[0319] The aforementioned TPU and thermoplastic polyurethane compositions containing the aforementioned TPU are suitable for applications such as dialysis catheters, fluid catheters, medical catheters, shoe soles, cushioning materials for shoes, and protective films for resins and metals. Furthermore, due to their excellent heat resistance, the aforementioned TPU and thermoplastic polyurethane compositions containing the aforementioned TPU are also suitable for applications such as automotive parts and industrial parts, where they may be used in high-temperature environments. Additionally, due to their excellent low-temperature properties, the aforementioned TPU and thermoplastic polyurethane compositions containing the aforementioned TPU are also suitable for applications such as conveyor belts for handling food at low temperatures, where thermoplastic polyurethane is used in low-temperature environments, or in cold regions.

Claims

1. A thermoplastic polyurethane comprising a structural unit A derived from a high molecular weight polyol a having hydroxyl groups at the ends, a structural unit B derived from a polyisocyanate b, and a structural unit C derived from a chain extender c. The high molecular weight polyol a comprises structural units derived from branched polyol a1 and polycarboxylic acid a2 with 7 to 11 carbon atoms, and has a number average molecular weight of 500 or higher. Of the total 100% by mass of the thermoplastic polyurethane structural units, 50% to 90% by mass of structural unit A, 8% to 45% by mass of structural unit B, and 2% to 10% by mass of structural unit C are included.

2. The thermoplastic polyurethane according to claim 1, wherein, Of the total 100% by mass of the thermoplastic polyurethane structural units, 60% to 90% by mass of structural unit A, 8% to 38% by mass of structural unit B, and 2% to 8% by mass of structural unit C are included.

3. The thermoplastic polyurethane according to claim 1 or 2, wherein, The branched polyol a1 is 3-methyl-1,5-pentanediol.

4. The thermoplastic polyurethane according to any one of claims 1 to 3, wherein, The chain extender c is a diol with a molecular weight of less than 500.

5. The thermoplastic polyurethane according to any one of claims 1 to 4, wherein, According to JIS K 7215-1986, the hardness of the A hardness tester is below HDA95.

6. The thermoplastic polyurethane according to any one of claims 1 to 5, wherein, According to JIS K 7215-1986, the hardness of the A hardness tester is below HDA80.

7. The thermoplastic polyurethane according to any one of claims 1 to 6, wherein the crystallization temperature is below -15°C or does not have a crystallization temperature.

8. The thermoplastic polyurethane according to any one of claims 1 to 7, wherein, The complex elastic modulus E of the sheet produced by injection molding at 150°C The complex elastic modulus E relative to 25℃ The ratio of E (150℃) / E (25℃) is above 0.

15.

9. A method for manufacturing thermoplastic polyurethane, comprising reacting at least 50% to 90% by mass of a high molecular weight polyol a having terminal hydroxyl groups, 8% to 45% by mass of a polyisocyanate b, and 2% to 10% by mass of a chain extender c to a total of 100% by mass of the raw material components of thermoplastic polyurethane to obtain thermoplastic polyurethane. The high molecular weight polyol a is a polyol containing structural units derived from branched polyol a1 and polycarboxylic acid a2 with 7 to 11 carbon atoms, and having a number average molecular weight of 500 or more.

10. The method for manufacturing thermoplastic polyurethane according to claim 9, wherein, In a total of 100% by mass of the raw material components of the thermoplastic polyurethane, at least 60% to 90% by mass of the polymeric polyol a with hydroxyl groups at the end, 8% to 38% by mass of the polyisocyanate b, and 2% to 8% by mass of the chain extender c are reacted to obtain the thermoplastic polyurethane.

11. The method for manufacturing thermoplastic polyurethane according to claim 9 or 10, wherein, A catalyst d of 0.1 ppm to 1000 ppm by mass is used relative to the total amount of the polymer polyol a, the polyisocyanate b, and the chain extender c.

12. A thermoplastic polyurethane composition comprising the thermoplastic polyurethane according to any one of claims 1 to 8.

13. A molded article comprising the thermoplastic polyurethane according to any one of claims 1 to 8.

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