Thermoplastic polyurethane composition for high rebound foam

Abstract

Provided is a composition including a microcellular foam including a thermoplastic polyurethane copolymer including a reaction product of the following reactants: (a) at least one diisocyanate; (b) at least one chain extender; and (c) a polyol blend comprising at least one polyether polyol and at least one polyolefin polyol; wherein the at least one polyolefin polyol makes up from 10 to 40 weight percent of the polyol blend, based on the total weight of the polyol blend; wherein the at least one polyolefin polyol is present in the thermoplastic polyurethane copolymer in an amount of from 5 to 25 weight percent, based on the total weight of the thermoplastic polyurethane copolymer; and wherein the thermoplastic polyurethane copolymer has a hard segment content of from 25 to 45 weight percent, based on the total weight of the thermoplastic polyurethane copolymer.

Description

4839-01THERMOPLASTIC POLYURETHANE COMPOSITION FOR HIGH REBOUND FOAM

[0001] The disclosed technology relates to thermoplastic polyurethane compositions, such as for use in high-rebound foams, as well as methods of making foam articles using the thermoplastic polyurethane compositions.

[0002] Thermoplastic polyurethane compositions (“TPU”) have a multitude of end uses. They have been used in foams for some applications, and one such application is in footwear. However, it is difficult to make foamed articles from TPU which result in the high-performance needs of certain footwear applications. The disclosed technology provides a TPU foam with a uniform structure (e.g., a microcellular foam) and mechanical performance properties which result in successful deployment of the TPU foam for use in footwear articles, such as midsoles, outsoles, and / or cushions for footwear.

[0003] In general, TPU foam compositions may be made by any known process, such as batch or continuous processes, including chemical and / or physical blowing agents. When physical blowing agents, such as nitrogen gas or supercritical carbon dioxide, are used, the foaming process is referred to as physical foaming, physical injection foaming, or physical injection molding. During physical injection foaming, the TPU is melted, mixed with the blowing agent, and injected into a mold; due to depressurization and / or cooling in the mold, the molded foam part is produced. Physical foaming may provide certain advantages, such as higher production rates and / or lower VOC production (due to not using chemical blowing agents).

[0004] Similarly, the disclosed TPU foam compositions may be made by any known process, but may provide particular benefits when used in physical injection molding processes. It is generally known in the art of TPU foams that particular combinations of TPUs and blowing agents can result in varying quality foams depending on the foaming process and / or blowing agent used. Thus, when used in a physical foaming process with a physical blowing agent, the TPUs disclosed herein have been found to unexpectedly provide the aforementioned uniform structure (e.g., a microcellular foam) and / or mechanical performance properties. For example, the disclosed TPU foam articles, made from physical injection molding processes, may provide a closed cell, low specific gravity (e.g., below 0.25) foam with high rebound (e.g., greater than 55%) and low compression set (e.g., less than 35%).4839-01

[0005] The subject matter disclosed herein provides a composition comprising a microcellular foam comprising a thermoplastic polyurethane copolymer comprising a reaction product of the following reactants: (a) at least one diisocyanate; (b) at least one chain extender; and (c) a polyol blend comprising at least one polyether polyol and at least one polyolefin polyol; wherein the at least one polyolefin polyol makes up from 10 to 40 weight percent of the polyol blend, based on the total weight of the polyol blend; and wherein the at least one polyolefin polyol is present in the thermoplastic polyurethane copolymer in an amount of from 5 to 25 weight percent, based on the total weight of the thermoplastic polyurethane copolymer.

[0006] Also provided is a method of making a microcellular foam article comprising: (a) providing particles of a thermoplastic polyurethane copolymer comprising a reaction product of: (a) at least one diisocyanate; (b) at least one chain extender; and (c) a polyol blend comprising at least one polyether polyol and at least one polyolefin polyol; wherein the at least one polyolefin polyol makes up from 10 to 40 weight percent of the polyol blend, based on the total weight of the polyol blend; and wherein the at least one polyolefin polyol is present in the thermoplastic polyurethane copolymer in an amount of from 5 to 25 weight percent, based on the total weight of the thermoplastic polyurethane copolymer; (b) melting the particles in a melting zone of a physical injection molding apparatus to create a molten thermoplastic polyurethane composition; (c) mixing the molten thermoplastic polyurethane composition with a blowing agent in a mixing zone of the physical injection molding apparatus to create a mixture of the molten thermoplastic polyurethane composition and the blowing agent; and (d) injecting the mixture into a mold, during and / or after which it expands and / or cools to create the microcellular foam article.

[0007] Also provided are foamed articles made from the composition(s) mentioned above and / or made via the method(s) mentioned above.

[0008] The following embodiments of the present subject matter are contemplated:

[0009] 1. A composition comprising a microcellular foam comprising a thermoplastic polyurethane copolymer comprising a reaction product of the following reactants: (a) at least one diisocyanate; (b) at least one chain extender; and (c) a polyol blend comprising at least one polyether polyol and at least one polyolefin polyol; wherein the at least one polyolefin polyol makes up from 10 to 40 weight percent of the polyol blend, based on the total weight of the polyol blend; wherein the at least one polyolefin polyol is present in the thermoplastic4839-01 polyurethane copolymer in an amount of from 5 to 25 weight percent, based on the total weight of the thermoplastic polyurethane copolymer; and wherein the thermoplastic polyurethane copolymer has a hard segment content of from 25 to 45 weight percent, based on the total weight of the thermoplastic polyurethane copolymer.

[0010] 2. The composition of embodiment 1, wherein the at least one polyolefin polyol comprises at least one unsaturated polybutadiene polyol.

[0011] 3. The composition of either embodiment 1 or embodiment 2, wherein the at least one polyolefin polyol has an average functionality of from 1.8 to 2.2.

[0012] 4 The composition of any one of embodiments 1 to 3, wherein the at least one polyolefin polyol has a number average molecular weight of from 1,000 to 2,500 g / mol.

[0013] 5. The composition of any one of embodiments 1 to 4, wherein the at least one poly ether polyol comprises at least one polyol of the general formula HO-(CxO)n-H, wherein x is an integer from 2 to 6, and wherein n is an integer selected to provide a polyol with a number average molecular weight of from 1,500 to 3,000 g / mol.

[0014] 6. The composition of embodiment 5, wherein x is 3 or 4 and n is selected to provide a polyol with a number average molecular weight of from 1,500 to 2,000 g / mol.

[0015] 7. The composition of any one of embodiments 1 to 6, wherein the at least one diisocyanate comprises at least one of methylene diphenyl diisocyanate, hexamethylene diisocyanate, methylene bis(4-cyclo-hexylisocyanate), dicyclohexylmethane 4,4 ’-diisocyanate, or hydrogenated methylene diphenyl diisocyanate.

[0016] 8. The composition of any one of embodiments 1 to 7, wherein the at least one diisocyanate comprises methylene diphenyl diisocyanate.

[0017] 9 The composition of any one of embodiments 1 to 8, wherein the at least one chain extender comprises at least one linear diol of the general formula CyH(2y+2)O2, wherein y is an integer from 2 to 12.

[0018] 10. The composition of any one of embodiments 1 to 8, wherein the at least one chain extender comprises at least one of ethylene glycol, 1,3 propanediol, 1,4 butanediol, 1,5 pentanediol, 1,6 hexanediol, 1,7 heptane diol, 1,8 octane diol, 1,9 nonane diol, 1,10 decanediol, 1,12 dodecane diol, benzene-1,4 diol, or benzene 1,3 diol.

[0019] 11. The composition of any one of embodiments 1 to 10, wherein the at least one chain extender comprises 1,4 butanediol.4839-01

[0020] 12. The composition of any one of embodiments 1 to 1 1, wherein the polyol blend is a fully miscible blend at a temperature of 90 °C or greater.

[0021] 13. The composition of any one of embodiments 1 to 12, wherein the polyol blend is a fully miscible blend at a temperature of from 90 to 150 °C.

[0022] 14. The composition of any one of embodiments 1 to 13, wherein the amount of the at least one polyether polyol in the polyol blend is higher than the amount of polyolefin polyol in the polyol blend.

[0023] 15. The composition of any one of embodiments 1 to 14, wherein the IsocyanateIndex of the thermoplastic polyurethane copolymer is from 0.95 to 1.05.

[0024] 16. The composition of any one of embodiments 1 to 15, wherein the thermoplastic polyurethane copolymer has a hardness of from 75 to 90 A, as measured by ASTM D2240.

[0025] 17. The composition of any one of embodiments 1 to 16, wherein the thermoplastic polyurethane copolymer has a rebound of at least 50%, as measured by ASTM D2632.

[0026] 18. A microcellular foam article comprising the composition of any one of embodiments 1 to 17.

[0027] 19. The microcellular foam article of embodiment 18, wherein the article has anAsker C durometer hardness of from 35 to 55, as measured by ASTM D2240.

[0028] 20. The microcellular foam article of either embodiment 18 or embodiment 19, wherein the article has a rebound of at least 55%, as measured by ASTM D2632 using a foam specimen having a thickness of 20 mm.

[0029] 21. The microcellular form article of any one of embodiments 18 to 20, wherein the article has a specific gravity of from 0.15 to 0.25, as measured by ASTM D792.

[0030] 22. The microcellular foam article of any one of embodiments 18 to 21, wherein the article has a compression set of less than 35%, as measured by ASTM D395B at 50 °C for 6 hours using a test specimen according to ASTM D395-18 with the sample being a cuboid of 25.4 mm by 25.4 mm and a thickness of 20 mm.

[0031] 23. A method of making a microcellular foam article comprising: (A) providing particles of a thermoplastic polyurethane copolymer comprising a reaction product of: (a) at least one diisocyanate; (b) at least one chain extender; and (c) a polyol blend comprising at least one polyether polyol and at least one polyolefin polyol; wherein the at least one polyolefin polyol makes up from 10 to 40 weight percent of the polyol blend, based on the total weight of4839-01 the polyol blend; wherein the at least one polyolefin polyol is present in the thermoplastic polyurethane copolymer in an amount of from 5 to 25 weight percent, based on the total weight of the thermoplastic polyurethane copolymer; and wherein the thermoplastic polyurethane copolymer has a hard segment content of from 25 to 45 weight percent, based on the total weight of the thermoplastic polyurethane copolymer; (B) melting the particles in a melting zone of a physical injection molding apparatus to create a molten thermoplastic polyurethane composition; (C) mixing the molten thermoplastic polyurethane composition with a blowing agent in a mixing zone of the physical injection molding apparatus to create a mixture of the molten thermoplastic polyurethane composition and the blowing agent; and (D) injecting the mixture into a mold, during and / or after which it expands and / or cools to create the microcellular foam article.

[0032] 24. The method of embodiment 23, wherein the at least one polyolefin polyol comprises at least one unsaturated polybutadiene polyol.

[0033] 25. The method of either embodiment 23 or embodiment 24, wherein the at least one polyolefin polyol has an average functionality of from 1.8 to 2.2.

[0034] 26. The method of any one of embodiments 23 to 25, wherein the at least one polyolefin polyol has a number average molecular weight of from 1,000 to 2,500 g / mol.

[0035] 27. The method of any one of embodiments 23 to 26, wherein the at least one polyether polyol comprises at least one polyol of the general formula HO-(CxO)n-H, wherein x is an integer from 2 to 6, and wherein n is an integer selected to provide a polyol with a number average molecular weight of from 1,500 to 3,000 g / mol.

[0036] 28. The method of embodiment 27, wherein x is 3 or 4 and n is selected to provide a polyol with a number average molecular weight of from 1,500 to 2,000 g / mol.

[0037] 29. The method of any one of embodiments 23 to 28, wherein the at least one diisocyanate comprises at least one of methylene diphenyl diisocyanate, hexamethylene diisocyanate, methylene bis(4-cyclo-hexylisocyanate), dicyclohexylmethane 4,4 ’-diisocyanate, or hydrogenated methylene diphenyl diisocyanate.

[0038] 30. The method of any one of embodiments 23 to 29, wherein the at least one diisocyanate comprises methylene diphenyl diisocyanate.4839-01

[0039] 31 The method of any one of embodiments 23 to 30, wherein the at least one chain extender comprises at least one linear diol of the general formula CyH(2y+2)C>2, wherein y is an integer from 2 to 12.

[0040] 32. The method of any one of embodiments 23 to 30, wherein the at least one chain extender comprises at least one of ethylene glycol, 1,3 propanediol, 1,4 butanediol, 1,5 pentanediol, 1,6 hexanediol, 1,7 heptane diol, 1,8 octane diol, 1,9 nonane diol, 1,10 decanediol, 1,12 dodecane diol, benzene-1,4 diol, or benzene 1,3 diol.

[0041] 33. The method of any one of embodiments 23 to 32, wherein the at least one chain extender comprises 1,4 butanediol.

[0042] 34 The method of any one of embodiments 23 to 33, wherein the polyol blend is a fully miscible blend at a temperature of 90 °C or greater.

[0043] 35. The method of any one of embodiments 23 to 34, wherein the polyol blend is a fully miscible blend at a temperature of from 90 to 150 °C.

[0044] 36. The method of any one of embodiments 23 to 35, wherein the amount of the at least one polyether polyol in the polyol blend is higher than the amount of polyolefin polyol in the polyol blend.

[0045] 37. The method of any one of embodiments 23 to 36, wherein the Isocyanate Index of the thermoplastic polyurethane copolymer is from 0.95 to 1.05.

[0046] 38. The method of any one of embodiments 23 to 37, wherein the thermoplastic polyurethane copolymer has a hardness of from 75 to 90 A, as measured by ASTM D2240.

[0047] 39 The method of any one of embodiments 23 to 38, wherein the thermoplastic polyurethane copolymer has a rebound of at least 50%, as measured by ASTM D2632.

[0048] 40. The method of any one of embodiments 23 to 39, wherein the blowing agent is nitrogen gas or supercritical carbon dioxide.

[0049] 41. A microcellular foam article made according to the method of any one of embodiments 23 to 40.

[0050] 42. The microcellular foam article of embodiment 41, wherein the article has anAsker C durometer hardness of from 35 to 55, as measured by ASTM D2240.

[0051] 43. The microcellular foam article of either embodiment 41 or embodiment 42, wherein the article has a rebound of at least 55%, as measured by ASTM D2632 using a foam specimen having a thickness of 20 mm.4839-01

[0052] 44. The microcellular form article of any one of embodiments 41 to 43, wherein the article has a specific gravity of from 0.15 to 0.25, as measured by ASTM D792.

[0053] 45. The microcellular foam article of any one of embodiments 41 to 44, wherein the article has a compression set of less than 35%, as measured by ASTM D395B at 50 °C for 6 hours using a test specimen according to ASTM D395-18 with the sample being a cuboid of 25.4 mm by 25.4 mm and a thickness of 20 mm.

[0054] Various features and embodiments of the present subject matter will be described below by way of non-limiting illustration.

[0055] The amount of each chemical component described herein is presented exclusive of any solvent or diluent oil, which may be customarily present in the commercial material, that is, on an active chemical basis, unless otherwise indicated. Unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade.

[0056] It is known that some of the materials described herein may interact in the final formulation, so that the components of the final formulation may be different from those that are initially added. The products formed thereby, including the products formed upon employing the composition of the present subject matter in its intended use, may not be susceptible of easy description. Nevertheless, all such modifications and reaction products are included within the scope of the present subject matter; the present subject matter encompasses the composition prepared by admixing the components described herein.

[0057] As used herein, the indefinite article “a” / “an” is intended to mean one or more than one. As used herein, the phrase “at least one” means one or more than one of the following terms. Thus, “a” / “an” and “at least one” may be used interchangeably. For example “at least one of A, B or C” means that just one of A, B or C may be included, and any mixture of two or more of A, B and C may be included, in alternative embodiments.

[0058] As used herein, the transitional term “comprising,” which is synonymous with “including,” “containing,” or “characterized by,” is inclusive or open-ended and does not exclude additional, un-recited elements or method steps. However, in each recitation of “comprising” herein, it is intended that the term also encompass, as alternative embodiments, the phrases “consisting essentially of’ and “consisting of,” where “consisting of’ excludes any4839-01 element or step not specified and “consisting essentially of’ permits the inclusion of additional un-recited elements or steps that do not materially affect the essential or basic and novel characteristics of the composition or method under consideration.

[0059] Provided is a composition comprising a microcellular foam comprising a thermoplastic polyurethane copolymer comprising a reaction product of the following reactants: (a) at least one diisocyanate; (b) at least one chain extender; and (c) a polyol blend comprising at least one polyether polyol and at least one polyolefin polyol; wherein the at least one polyolefin polyol makes up from 10 to 40 (such as from 15 to 40, from 20 to 40, from 25 to 40, from 30 to 40, from 35 to 40, from 10 to 35, from 15 to 35, from 20 to 35, from 25 to 35, from 30 to 35, from 10 to 30, from 15 to 30, from 20 to 30, from 25 to 30, from 10 to 25, from 15 to 25, from 20 to 25, from 10 to 20, from 15 to 20, or from 10 to 15) weight percent of the polyol blend, based on the total weight of the polyol blend; and wherein the at least one polyolefin polyol is present in the thermoplastic polyurethane copolymer in an amount of from 5 to 25 (such as from 10 to 25, from 15 to 25, from 20 to 25, from 5 to 20, from 10 to 20, from 15 to 20, from 5 to 15, from 10 to 15, or from 5 to 10) weight percent, based on the total weight of the thermoplastic polyurethane copolymer. It would be understood by a person of ordinary skill in the art that certain specific selections which fall within the broadest embodiment described in this paragraph may not be physically possible, since the amount of polyolefin polyol in the polyol blend and in the thermoplastic polyurethane copolymer are both specified, and these amounts are related to each other. Thus, depending on whether and to what extent other materials may be present in the thermoplastic polyurethane copolymer, it may not, for example, be possible to have the polyolefin polyol be present in the polyol blend at just 10 weight percent, while also being present in the thermoplastic polyurethane copolymer in an amount of 25 weight percent; as another example, it may not be possible for the polyolefin polyol to be present in the polyol blend at 40 weight percent, but make up only 5 weight percent of the thermoplastic polyurethan composition. However, it is simple for a person of ordinary skill in the art to make this determination when a thermoplastic polyurethane composition is being designed and / or made, because it will be known how much polyolefin polyol is being added to the polyol blend, and, from there, it will be easy to ascertain how much of the polyolefin polyol is present in the thermoplastic polyurethane copolymer based on all ingredients incorporated into the thermoplastic polyurethane copolymer. Any such specific4839-01 embodiments which fall within the scope of the broadest embodiment described in this paragraph which are not physically possible are not contemplated as being within the scope of the broadest embodiments.

[0060] In certain embodiments, the at least one polyolefin polyol comprises at least one unsaturated polybutadiene polyol. In certain embodiments, the at least one polyolefin polyol has an average functionality of from 1.8 to 2.2. In certain embodiments, the at least one polyolefin polyol is difunctional. In certain embodiments, the at least one polyolefin polyol has a number average molecular weight of from 1,000 to 2,500 g / mol (such as from 1,500 to 2,500, from 2,000 to 2,500, from 1,000 to 2,000, from 1,500 to 2,000, or from 1,000 to 1,500 g / mol).

[0061] In certain embodiments, the polyolefin polyol is a polyol which contains polyolefin segments, which may be obtained from multi-ethylenically unsaturated monomers. The multi- ethylenically unsaturated monomers may be diethylenically- or triethylenically-unsaturated monomers. In certain embodiments, the multi-ethylenically unsaturated monomers are alkyl- group-substituted, multi-ethylenically unsaturated monomers, such as conjugated diene monomers. The alkyl group may be a linear alkyl group and / or a cycloalkyl group. The conjugated diene monomer may contain 4 to 10 carbon atoms, such as 4 to 6 carbon atoms. In certain embodiments, the conjugated diene monomer is butadiene and / or isoprene.

[0062] In certain embodiments, the polyolefin polyol may be a polybutadiene polyol. In certain embodiments, the polybutadiene polyol is unsaturated. In certain embodiments, the polybutadiene polyol comprises or consists of polybutadiene diol, which as used herein, also refers to hydroxyl-terminated polybutadiene. The molecular weight of the polybutadiene polyol depends on the desired characteristics of article to be made. In certain embodiments, the polybutadiene polyol is unsaturated, such that the polybutadiene polyol contains double bonds along the butadiene chain. Commercially available polybutadiene polyols useful in the present subject matter include KRASOL™ LBH P-2000, KRASOL™ LBH 2000, available from Cray Valley, and NISSO™ PB G 3000, NISSO™ PB G 2000, available from Nippon Soda Co.

[0063] In a preferred embodiment, the polyolefin polyol is a polydiene polyol, more preferred is polybutadiene diol, polyisoprene diol, or combination thereof.

[0064] In certain embodiments, the at least one polyether polyol comprises at least one polyol of the general formula HO-(CxO)n-H, wherein x is an integer from 2 to 6 (such as from 3 to 6, from 4 to 6, from 5 to 6, from 2 to 5, from 3 to 5, from 4 to 5, from 2 to 4, from 3 to 4,4839-01 or from 2 to 3), and wherein n is an integer selected to provide a polyol with a number average molecular weight of from 1,500 to 3,000 g / mol (such as from 2,000 to 3,000, from 2,500 to 3,000, from 1,500 to 2,500, from 2,000 to 2,500, or from 1,500 to 2,000 g / mol). In certain embodiments, x is 3 or 4 and n is selected to provide a polyol with a number average molecular weight of from 1,500 to 2,000 g / mol.

[0065] Number average molecular weights described herein are determined as follows: Hydroxyl (“OH”) number is determined according to the potentiometric titration method according to ASTM El 899. Based on the determined OH number and the known functionality of the polyol (“number of OH groups per molecule”), number average molecular weight (“molecular weight (g / mol)”) is determined using the following formula:56100 X number of OH groups per molecule molecular weight ig / moH ™ - -VJTT — ~ -In the case of a pure compound, the hydroxyl number is inversely proportional to the hydroxyl equivalent weight and the molecular weight.

[0066] In certain embodiments, the at least one diisocyanate comprises at least one of methylene diphenyl diisocyanate, hexamethylene diisocyanate, methylene bis(4-cyclo- hexylisocyanate), dicyclohexylmethane 4,4’-diisocyanate, or hydrogenated methylene diphenyl diisocyanate. In certain embodiments, the at least one diisocyanate comprises methylene diphenyl diisocyanate.

[0067] The chain extender used in the thermoplastic polyurethane composition may be any chain extender which would be suitable for use in the thermoplastic polyurethane composition. In certain embodiments, the at least one chain extender comprises at least one linear diol of the general formula CyH(2y+2)O2, wherein y is an integer from 2 to 12 (such as from 3 to 12, from 4 to 12, from 6 to 12, from 8 to 12, from 10 to 12, from 2 to 10, from 3 to 10, from 4 to 10, from 6 to 10, from 8 to 10, from 2 to 8, from 3 to 8, from 4 to 8, from 6 to 8, from 2 to 6, from 3 to 6, from 4 to 6, from 2 to 4, from 3 to 4, or from 2 to 3).

[0068] In certain embodiments, the at least one chain extender comprises at least one of ethylene glycol, 1,3 propanediol, 1,4 butanediol, 1,5 pentanediol, 1,6 hexanediol, 1,7 heptane diol, 1,8 octane diol, 1,9 nonane diol, 1,10 decanediol, 1,12 dodecane diol, benzene-1,4 diol, or benzene 1,3 diol. In certain embodiments, the at least one chain extender comprises 1,4 butanediol.4839-01

[0069] In certain embodiments, the polyol blend is a fully miscible blend at a temperature of 90 °C or greater (such as 100 °C or greater, 110 °C or greater, 120 °C or greater, 130 °C or greater, 140 °C or greater,). In certain embodiments, the polyol blend is a fully miscible blend at a temperature of from 90 to 150 °C (such as from 100 to 150 °C, from 110 to 150 °C, from 120 to 150 °C, from 130 to 150 °C, from 140 to 150 °C, from 90 to 140 °C, from 100 to 140 °C, from 110 to 140 °C, from 120 to 140 °C, from 130 to 140 °C, from 90 to 130 °C, from 100 to 130 °C, from 110 to 130 °C, from 120 to 130 °C, from 90 to 120 °C, from 100 to 120 °C, from 110 to 120 °C, from 90 to 110 °C, from 100 to 110 °C, or from 90 to 100 °C). By “a fully miscible blend”, what is meant in this context is that the components of the polyol blend are miscible with themselves at the described temperature.

[0070] In certain embodiments, the amount of the at least one polyether polyol in the polyol blend is higher than the amount of polyolefin polyol in the polyol blend. Without wishing to be limited by theory, it is believed that mechanical properties may be less desirable as the amount of polyether polyol decreases relative to the amount of polyolefin polyol in the polyol blend, and this may also cause miscibility issues.

[0071] In certain embodiments, the Isocyanate Index of the thermoplastic polyurethane copolymer is from 0.95 to 1.05 (such as from 0.96 to 1.05, from 0.97 to 1.05, from 0.98 to 1.05, from 0.95 to 1.04, from 0.96 to 1.04, from 0.97 to 1.04, or from 0.98 to 1.04). By “Isocyanate Index”, what is meant in this context is the molar ratio of isocyanate groups provided by the diisocyanate to the sum of hydroxyl groups provided by the polyol blend and the chain extender; this is easily determined theoretically based on the identities of the diisocyanate, the polyol blend, and the chain extender.

[0072] In certain embodiments, the thermoplastic polyurethane copolymer has a hardness of from 75 to 90 A, as measured by ASTM D2240.

[0073] In certain embodiments, the thermoplastic polyurethane copolymer has a rebound of at least 50% (such as at least 55%), as measured by ASTM D2632. In certain embodiments, the thermoplastic polyurethane copolymer has a rebound of from 50% to 100% (such as from 50% to 90%, from 50% to 80%, from 50% to 70%, from 55% to 100%, from 55% to 90%, from 55% to 80%, or from 55% to 70%), as measured by ASTM D2632.

[0074] In certain embodiments, the thermoplastic polyurethane copolymer has a hard segment content of from 25 to 45 (such as from 30 to 45, from 35 to 45, from 40 to 45, from 254839-01 to 40, from 30 to 40, from 35 to 40, from 25 to 35, from 30 to 35, or from 25 to 30) weight percent, based on the total weight of the thermoplastic polyurethane copolymer. Thermoplastic polyurethanes (“TPU”) are random block copolymers which include hard segments and soft segments. Hard segments are generally formed from alternative sequences of the isocyanate and the chain extender present in the TPU, while the soft segments are generally formed from the polyol chain present in the TPU. Hard segments have a tendency to self-assemble due to hydrogen bonding to form hard domains in the TPU. Size and relative fraction of hard domains determine stiffness and modulus of the TPU. Hard segment content is defined as the sum of weight percentage of diisocyanate and chain extender in the TPU to the total weight of all reactants that make up the TPU. For a given TPU chemistry, as hard segment content increases, it would be expected that the hardness of the TPU would also increase.

[0075] The composition(s) described above may include other materials, such as additives and / or catalysts, incorporated into the composition, the microcellular foam, and / or the thermoplastic polyurethane copolymer. Such materials which may be added to the compositions described above in this manner are well known in the relevant field.

[0076] Additives which may be incorporated into the compositions described above may include antioxidants, organic phosphites, phosphines and phosphonites, hindered amines, organic amines, organo sulfur compounds, lactones and hydroxylamine compounds, biocides, fungicides, antimicrobial agents, compatibilizers, electro-dissipative or anti-static additives, fillers and reinforcing agents, such as titanium dixide, alumina, clay and carbon black, flame retardants, such as phosphates, halogenated materials, and metal salts of alkyl benzenesulfonates, impact modifiers, such as methacrylate-butadiene-styrene ("MBS") and methylmethacrylate butylacrylate ("MBA"), lubricants, mold release agents such as waxes, fats and oils, pigments and colorants, plasticizers, polymers, rheology modifiers such as monoamines, polyamide waxes, silicones, and polysiloxanes, slip additives, such as paraffinic waxes, hydrocarbon polyolefins and / or fluorinated polyolefins, and UV additives (such as UV stabilizers). Other additives may be used to enhance the performance of the TPU composition or blended product. All of the additives described above may be used in an effective amount customary for these substances.

[0077] Antioxidants may be added during the polymerization reaction, or blended into the previously-formed thermoplastic polyurethane composition(s) described herein, such as in an4839-01 amount of from 0.3 to 2 percent by weight, based on the total weight of the thermoplastic polyurethane composition. Suitable antioxidants include phenolic types, organic phosphites, phosphines and phosphonites, hindered amines, organic amines, organo sulfur compounds, lactones and hydroxylamine compounds. Many suitable antioxidant materials are available commercially. These include Irganox™ 1010, Irganox™ MD1024, Irgafos™ 168, Irgafos™ 126, all available from BASF Specialty Chemicals, and the like.

[0078] UV additives, such as UV stabilizers and / or UV absorbers (all of which may be similar or different compositions depending on preferred nomenclature in different circumstances), may be used in the thermoplastic polyurethane compositions described herein. UV additives may be used for many reasons, such as to prevent the thermoplastic polyurethane composition(s) from changing color, losing clarity, and / or impacting mechanical properties.

[0079] Suitable UV light stabilizers include hindered amine light stabilizers (HALS) and UV light absorber (UVA) additives. Blends of HAL and UVA additives are also effective. Representative HALS that can be used in the practice of this invention include, but are not limited to, Sterically hindered amines as well as the N derivatives thereof (e.g., N-alkyl, N- hydroxy, N-alkoxy and N-acyl), such as bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate; bis(2,2,6,6tetramethylpiperidin-4-yl) succinate; bis(l, 2,2,6, 6-pentamethylpiperidin-4- yl)sebacate; bis(l-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate; bis(l,2,2,6,6- pentamethylpiperidin-4-yl) n-butyl 3,5-di-tert-butyl-4-hydroxybenzylmalonate; the condensate of l(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid; the condensate of N,N’-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylenediamine and 4-tert- octylamino-2,6-dichloro-l,3,5-triazine; tris(2,2,6,6-tetramethylpiperidin-4-yl) nitrilotriacetate; tetraki s(2,2,6,6-tetramethylpiperidin-4yl)- 1 ,2,3 ,4-butanetetracarboxylate; 1,1'-(l,2ethanediyl)bis(3,3,5,5-tetramethylpiperazinone); 4-benzoyl-2,2,6,6-tetramethylpiperidine; 4-stearyloxy-2,2,6,6-tetramethylpiperidine; bis(l,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2- (2-hydroxy-3,5-di-tert-butylbenzyl) mal onate; 3-n-octyL7, 7,9, 9-tetramethyl- 1,3,8- triazaspiro[4.5]decan-2, 4-dione; bis(l-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate; bis(L octyloxy-2,2,6,6-tetramethylpiperidyl)succinate; the condensate of N, N'-bis(2, 2,6,6- tetramethylpiperidin4-yl) hexamethylenediamine and 4-morpholino-2,6-dichlorol,3,5-triazine; the condensate of 2-chloro-4,6-bis(4-nbutylamino-2,2,6,6-tetramethylpiperidyl)-l,3,5-triazine and l,2-bis(3-aminopropylamino)ethane; the condensate of 2-chloro-4,6-bis(4-n-butylamino-4839-01 l,2,2,6,6-pentamethylpiperidyl)-l,3,5-triazine and l,2-bis-(3aminopropylamino)ethane; 8- acetyl-3-dodecyl-7,7,9,9-tetramethyl-l,3,8-triazaspiro[4.5]decane-2,4-dione; 3-dodecyl-l- (2,2,6,6-tetramethylpiperidin4-yl)pyrrolidin-2,5-dione; 3-dodecyl-l-(l-ethanoyl-2,2,6,6tetramethylpiperidin-4-yl) pyrrolidin-2, 5-dione; 3-dodecyl-L(l,2,2,6,6- pentamethylpiperidin-4yl)pyrrolidine-2, 5-dione; a mixture of 4-hexadecyloxyand 4- stearyloxy-2,2,6,6-tetramethylpiperidine; the condensate of N,N'-bis(2,2,6,6- tetramethylpiperidin-4yl) hexamethylenediamine and 4-cyclohexylamino-2,6-dichloro-l,3,5- triazine; the condensate of l,2-bis(3-aminopropylamino)ethane, 2,4,6-trichloro-l,3,5-triazine and 4-butylamino-2,2,6,6-tetramethylpiperidine, 2-undecyl-7,7,9,9-tetramethyl-l-oxa-3,8- diaza-4-oxospiro[4.5]decane; oxo-piperanzinyl-triazines and similar materials disclosed in US5071981; photobondable HALS and similar materials disclosed in GB-A-2269819; and the reaction product of 7,7,9,9-tetramethyl-2-cycloundecyl-l-oxa-3,8-diaza-4oxospiro[4.5]decane and epichlorohydrin. See also generally US4619956, US5106891, GB-A-2269819, EP- A0309400, EP-A-0309401, EP-A-0309402 and EP-A-0434608. Some commercially available examples of HALS additives are Tinuvin® 123, Tinuvin 123-DW, Tinuvin 144, Tinuvin 152, Tinuvin 292, Tinuvin 622-SF, Tinuvin 770-DF, Tinuvin 5100 (the Tinuvin® series of additives are available from BASF), Chimassorb® 119, Chimassorb 2020 (the Chimassorb® series of additives are available from BASF), Lowilite® 76, Lowilite 62 (the Lowilite® series of additives are available from Addivant), Uvinul® 4050FF (BASF), LA-52, LA-576, LA-63P, 68, 72, 77Y, 77G, 81, 82, 87, 4042F, 502XP (the LA series of additives are available from Adeka Corporation), Hostavin® N30, Hostavin N845PP, Hostavin 3050, Hostavin 3051, Hostavin 3052, Hostavin 3053, Hostavin 3055, Hostavin 3058, Hostavin 3065, Hostavin PR- 31 (the Hostavin® series of additives are available from Clariant), and Nylostab® S-EED® (available from Clariant), Additional preferred hindered amine light stabilizer may be listed in the Plastics Additives Handbook 6th Edition, Hans Zweifel, Ralph Maier, Michael Schiller (Hanser Publications, Inc., Cincinnati, Ohio, USA, 2009). If present, then the HALS is typically present in an amount of greater than 0 to 4, more typically of 0.2 to 3 and even more typically of 0.5 to 2, wt% based on the weight of the composition.

[0080] Without being bound by theory, typically a UV stabilizer works by scavenging the free radicals and / or hydroperoxides formed by UV light damage while a UV absorber works by absorbing and dissipation the UV radiation. Suitable UV absorbers include, but are not limited4839-01 to, triazines, benzoxazinones, benzotriazoles, benzophenones, benzoates, formamidines, cinnamates / propenoates, aromatic propanediones, benzimidazoles, cycloaliphatic ketones, formanilides (including oxamides), cyanoacrylates, benzopyranones, salicylates, and mixtures of two or more of these.

[0081] Suitable benzophenone UV absorbers include, but are not limited to, 2-hydroxy-4- methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone or sulisobenzone, 2-(4- benzoyl-3-hydroxyphenoxy)-2-propenoic acid ethyl ester, homopolymer of 4-(2- acryloyloxyethoxy)-2-hydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone or dioxybenzone, 2-hydroxy-4-(2-hydroxy-3 -decyl oxypropoxy) benzophenone and 2-hydroxy-4- (2-hydroxy-3-octyloxypropoxy) benzophenone, 2,4,4'-trihydroxybenzophenone, 2-hydroxy-4- (isooctyloxy) benzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4,4'- dimethoxy-5,5'-disulfobenzophenone, disodium salt, 2,4-dihydroxybenzophenone or 4- benzoylresorcinol, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2, 2', 4,4'- tetrahydroxybenzophenone, 2,2'-dihydroxy-4-(2-hydroxyethoxy)benzophenone, 2-hydroxy-4- benzyloxybenzophenone, and mixtures of two or more of these. MAXGARD® 300, MAXGARD® 400, MAXGARD® 500, MAXGARD® 600, MAXGARD® 700, MAXGARD® 900, MAXGARD® 1000 MAXGARD® 1800, (The Maxgard series of chemicals can be obtained from Lycus LTD)

[0082] Suitable benzopyranone UV absorbers include, but are not limited to, 3, 3', 4', 5,7- pentahydroxyflavone or quercetin.

[0083] Suitable benzotriazole UV absorbers include, but are not limited to, 2-[2-hydroxy- 5-(l,l,3,3-tetramethylbutyl)phenyl]benzotriazole, 2-(2'-hydroxy-5'-(2- hydroxyethyl))benzotriazole, 2-(2'-hydroxy-5'-methacrylyloxyethylphenyl)-2H-benzotriazole, 1, 1, l-tris(hydroxyphenyl) ethane benzotri azole, 5-t-butyl-3-(5-chloro-2H-benzotriazol-2-yl)-4- hydroxybenzenepropanoic acid octyl ester and 3-(5-chloro-2H-benzotriazol-2-yl)-5-t-butyl-4- hydroxybenzenepropanoic acid octyl ester, a-[3-[3-(2H-benzotriazol-2-yl)-5-t-butyl-4- hydroxyphenyl]-l-oxopropyl]-co-hydroxy poly (oxy- 1,2-ethanediyl) and a-[3-[3-(2H- benzotriazol-2-yl)-5-t-butyl-4-hydroxyphenyl]-l-oxopropyl]-w-[3-[3-(2H-benzotriazol-2-yl)- 5-t-butyl-4-hydroxyphenyl]-l-oxopropoxy]poly(oxy-l,2-ethanediyl), 2-(2 -Hydroxy-3, 5 -di -t- butylphenyl) benzotriazole, 2-(2-hydroxy-3-t-butyl-5-methylphenyl)-5-chloro-2H- benzotriazole, 2-(3'-5'-di-t-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole, 2-(2 -Hydroxy-3, 5-4839-01 di-t-amylphenyl)benzotriazole, 3-(2H-benzotriazol-2-yl)-5-t-butyl-4- hydroxybenzenepropanoic acid, 2-(2H-benzotriazol-2-yl)-4-methyl-6-dodecylphenol, 3-(2H- benzotriazol-2-yl)-5-t-butyl-4-hydroxy-l,6-hexanediyl ester of benzenepropanoic acid and 3- (2H-benzotriazol-2-yl)-5-t-butyl-4-hydroxy-methyl ester of benzenepropanoic acid, 2-[2- hydroxy-3,5-bis-(l, 1 -dimethylbenzyl) phenyl]-2H-benzotriazole, 2-(2H-benzotriazol-2-yl)-6- (1 -methyl- l-phenylethyl)-4-(l, 1,3, 3 -tetramethylbutyl) phenol, 3-(2H-benzotriazol-2-yl)-5-t- butyl-4-hydroxybenzenepropanoic acid, C7-9 branched and linear alkyl esters, 2-(2-hydroxy- 5-methylphenyl) benzotriazole, 2-(2'-hydroxy-3'-sec-butyl-5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) benzotriazole, bis[2-hydroxy-3-(2H-benzotriazol-2-yl)-5- octylphenyl]methane, and mixtures of two or more of these. Some commercially avaialable examples of suitable benzotriazole UV absorbers include, but are not limited to TINUVIN® 99, TINUVIN 109, TINUVIN 234, TINUVIN 328, TINUVIN 350, TINUVIN 360 TINUVIN 384-2, TINUVIN 571, TINUVIN 1130, and TINUVIN P. (The Tinuvin series of additives are available from BASF).

[0084] Suitable benzoate UV absorbers include, but are not limited to, hexadecyl 3,5-dit- butyl-4-hydroxybenzoate, 3-hydroxyphenylbenzoate, ethyl-4-[[(ethylphenylamino)methylene] amino]benzoate, phenyl 2-hydroxybenzoate or phenylsalicylate, 2,4-di-t-butylphenyl-3,5-di-t- butyl-4-hydroxybenzoate, 4-bis(polyethoxy)amino acid polyethoxy ethyl ester, 4-t-butylphenyl 2-hydroxybenzoate or 4-t-butylphenylsalicylate, and mixtures of two or more of these. Some commercially available examples of suitable UV absorbers of this type include, but are not limited to SEESORB 300; SEESORB 201; SEESORB 202 (The SEESORB UV absorbers are available from Shipro Kasei Kaisha, Ltd.); TINUVIN 120 (available from BASF); UVINUL® P 25 (available from BASF).

[0085] Suitable benzoxazinone UV absorbers include, but are not limited to, 2,2'-(p- phenylene) di-3,l-benzoxazin-4-one. A commercially available example of a suitable UV absorbers of this type includes, but is not limited to CYASORB 3638 (from Syensqo).

[0086] Suitable cinnamates or propenoate UV absorbers include, but are not limited to, dimethyl (p-methoxybenzylidene) malonate, and 3-(4-methoxyphenyl)-2-propenoic acid 2- ethylhexyl ester or octyl p-methoxycinnamate.

[0087] Suitable cyanoacrylate UV absorbers include, but are not limited to, ethyl-2-cyano- 3,3-diphenylacrylate,; 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, l,3-bis-[(2'-cyano-3,3'-4839-01 diphenylacryloyl)oxy]-2,2-bis-{[(2-cyano-3',3'-diphenylacryloyl)oxy]methyl}propane, and 2- cyano-3-(2-methylindolinyl) methylacrylate, Some commercially available examples of suitable UV absorbers of this type include, but are not limited to UVINUL® 3030, UVINUL 3035, and UVINUL 3039. The Uvinul series of additives are available from BASF.

[0088] Suitable cycloaliphatic ketone UV absorbers include, but are not limited to, 3-(4- methylbenzylidene)-D,L-camphor.

[0089] Suitable formamidine UV absorbers include, but are not limited to, ethyl-4- [[(methylphenylamino)methylene]amino]benzoate.

[0090] Suitable formanilide (including oxamide) UV absorbers include, but are not limited to, N-(2-ethoxyphenyl)-N'-(4-isododecylphenyl) oxamide, N-[5-t-Butyl-2-ethoxyphenyl)-N'- (2-ethylphenyl) oxamide, N-(2-ethoxyphenyl)-N'-(2-ethylphenyl) oxamide, 2H- benzimidazole-2-carboxylic acid (4-ethoxyphenyl) amide, and mixtures of two or more of these. Some commercially avaialable examples of these types of additives are Hostavin® 3206 from Clariant and TINUVIN® 312 from BASF.

[0091] Suitable triazine UV absorbers include, but are not limited to, 2-[4,6-bis(2,4- dimethylphenyl)-l,3,5-triazin-2-yl]-5-octyloxyphenol, 2-(4,6-diphenyl-l,3,5-triazin-2-yl)-5- hexyloxyphenol, 2-[4-((2-Hydroxy-3-dodecyloxy-propyl)oxy)-2-hydroxyphenyl]-4,6-bis(2,4- dimethylphenyl)-l,3,5-triazine, 2,4,6-Trianilino-p-(carbo-2'-ethylhexyl-r-oxy)-l,3,5-triazine, and mixtures of two or more of these. TINUVIN® 400; TINUVIN 1577 ED; UVINUL T-150 from BASF.

[0092] Suitable salicylate UV absorbers include, but are not limited to, 3,3,5- trimethylcyclohexylsalicylate or homomethyl salicylate, and menthyl-o-aminobenzoate. Some commercially available examples of these types of additives are NEO HELIOPAN® HMS and NEO HELIOPAN® MA available from Symrise AG.

[0093] If present, then the UV additive may be present in an amount of from greater than 0 to 4, from 0.2 to 3, or from 0.3 to 2 weight percent, based on the total weight of the thermoplastic polyurethane composition.

[0094] Lubricants may be added to the thermoplastic polyurethane composition(s) described herein for various reasons, such as to aid in processing, to reduce friction, for wear resistance, to improve thermal stability, and / or to enhance mechanical properties, such as in an amount of from 0.1 to 1.5 percent by weight, based on the total weight of the thermoplastic4839-01 polyurethane composition. Lubricants may act as processing aids by reducing the melt viscosity of TPUs, enhancing flow properties during processing, and may help in improving melt stability and preventing melt fracture, resulting in smoother processing and reducing the risk of surface defects. Lubricants may reduce friction between polymer chains, enhancing the slip and release properties of TPUs, which may improve the surface quality of molded parts, facilitates demolding, and prevents sticking or blocking issues. Certain lubricants, such as metallic stearates, may improve the wear resistance of TPUs, such as by forming a lubricating layer on the surface, reducing frictional forces and preventing excessive wear and abrasion. Lubricants may contribute to the thermal stability of TPUs by acting as stabilizers; metallic stearates, for example, may provide thermal stability by scavenging free radicals and preventing degradation during processing or long-term use. In some cases, lubricants may improve the mechanical properties of TPUs, such as by modifying the hardness, tensile strength, and / or elongation at break of the material, depending on the type and amount of lubricant used.

[0095] The TPUs described herein may be made according to any known, suitable process. For example, the “one-shot” process may be used, where the reactants are added to an extruder reactor and reacted. In certain embodiments, the TPU may be prepared utilizing a pre-polymer process, where the polyol intermediates are reacted with generally an equivalent excess of one or more diisocyanates to form a pre-polymer solution having free or unreacted diisocyanate therein. Subsequently, a chain extender, may be added in an equivalent amount generally equal to the isocyanate end groups as well as to any free or unreacted diisocyanate compounds. The pre-polymer route may be carried out in any conventional device, such as an extruder. Through the extrusion process, the TPU may be formed into various end products such as pellets and granules.

[0096] It may be desirable to utilize catalysts such as stannous and other metal carboxylates as well as tertiary amines in making the TPUs described herein. Examples of suitable catalysts which accelerate the reaction between the NCO groups of the diisocyanates and the hydroxyl groups of the polyols and chain extenders are conventional tertiary amines, e g. triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2- (dimethylaminoethoxy)ethanol, diazabicyclo[2.2.2]octane and the like, and also organometallic compounds, such as titanic esters, iron compounds, e.g. ferric acetylacetonate, tin compounds, e.g. stannous diacetate, stannous dioctoate, stannous dilaurate, or the dialkyltin salts of aliphatic4839-01 carboxylic acids, e.g. dibutyltin diacetate, dibutyltin dilaurate, or the like, phenyl mercuric propionate, lead octoate, iron acetylacetonate, magnesium acetylacetonate, or bismuth compounds such as bismuth octoate, bismuth laurate, or the like.

[0097] Various types of optional components may be present during the polymerization reaction to make the TPU, and / or otherwise incorporated into the TPU. These include, but are not limited to, antioxidants, biocides, compatibilizers, electro-dissipative antistatic additives, fillers / reinforcing agents, flame and fire retardants, fungicides, impact modifiers, pigments, colorants, plasticizer, polymers, rheology modifiers, slip additives, and UV stabilizers. All of the additives described above may be used in an effective amount customary for these substances. These additional additives may be incorporated into the components of, or into the reaction mixture for, the preparation of the TPU resin, or after making the TPU resin. In another process, all the materials can be mixed with the TPU resin and then melted or they can be incorporated directly into the melt of the TPU resin.

[0098] Also provided is a microcellular foam article comprising a composition as described above and / or made according to the method(s) described below. The microcellular foam article may have an Asker C durometer hardness of from 35 to 55, as measured by ASTM D2240. The microcellular foam article may have a rebound of at least 55%, as measured by ASTM D2632 using a foam specimen having a thickness of 20 mm. The microcellular foam article may have a rebound from 55% to 100% (such as from 55% to 90%, from 55% to 80%, or from 55% to 70%), as measured by ASTM D2632 using a foam specimen having a thickness of 20 mm. The microcellular form article may have a specific gravity of from 0.15 to 0.25, as measured by ASTM D792. The microcellular foam article may have a compression set of less than 35% (such as less than 30%, or less than 25%), as measured by ASTM D395B at 50 °C for 6 hours using a test specimen according to ASTM D395-18 with the sample being a cuboid of 25.4 mm by 25.4 mm and a thickness of 20 mm. The microcellular foam article may have a compression set of from 0% to 35% (such as from 5%> to 35%, from 10% to 35%>, from 15% to 35%, from 0% to 30%, from 5% to 30%, from 10% to 30%, from 15% to 30%, from 0% to 25%, from 5% to 25%, from 10% to 25%, orfrom 15% to 25%), as measured by ASTM D395B at 50 °C for 6 hours using a test specimen according to ASTM D395-18 with the sample being a cuboid of 25.4 mm by 25.4 mm and a thickness of 20 mm.4839-01

[0099] Also provided is a method of making a microcellular foam article comprising: (a) providing particles of a thermoplastic polyurethane copolymer (such as the thermoplastic polyurethane copolymer(s) described above) comprising a reaction product of: (i) at least one diisocyanate; (ii) at least one chain extender; and (iii) a polyol blend comprising at least one polyether polyol and at least one polyolefin polyol; wherein the at least one polyolefin polyol makes up from 10 to 40 weight percent of the polyol blend, based on the total weight of the polyol blend; and wherein the at least one polyolefin polyol is present in the thermoplastic polyurethane copolymer in an amount of from 5 to 25 weight percent, based on the total weight of the thermoplastic polyurethane copolymer; (b) melting the particles in a melting zone of a physical injection molding apparatus to create a molten thermoplastic polyurethane composition; (c) mixing the molten thermoplastic polyurethane composition with a blowing agent in a mixing zone of the physical injection molding apparatus to create a mixture of the molten thermoplastic polyurethane composition and the blowing agent; and (d) injecting the mixture into a mold, during and / or after which it expands and / or cools to create the microcellular foam article.

[0100] By “particles”, it is meant in this context that the thermoplastic polyurethane copolymer is provided in a particulate form, such as pellets, granules, or flakes. The particles may be of any size and / or shape which would be suitable for use in the method (e.g., are capable of being fed into a physical injection molding apparatus), as would be understood by a person of ordinary skill in the art. The distinctions between pellets, granules, and flakes may be related to the size and / or shape of the particle. For example, pellets and granules may be of roughly the same particulate size, but could vary mostly in their shape, with pellets perhaps being more uniform in shape and granules perhaps being more random.

[0101] Any physical blowing agent which is suitable for use with the thermoplastic polyurethane copolymer(s) described herein to create the microcellular foam(s) disclosed herein may be used in the process described above. Physical blowing agents may include, but are not limited to linear, branched or cyclic Ci to Ce hydrocarbons, linear branched or cyclic Ci to Ce fluorocarbons; N2, O2, argon, CO2, supercritical CO2, or any suitable combination thereof. In certain embodiments, the blowing agent is nitrogen gas and / or supercritical carbon dioxide. In certain embodiments, the blowing agent is at least one of nitrogen gas or supercritical carbon4839-01 dioxide. In certain embodiments, the blowing agent is nitrogen gas or supercritical carbon dioxide.

[0102] The subject matter disclosed herein may be better understood with reference to the following examples, which are set forth merely to further illustrate the subject matter disclosed herein. The illustrative examples should not be construed as limiting the subject matter in any manner.

[0103] Various TPU comparative examples and examples according to the present subject matter were prepared according to Table 1 and the methods described below. In Table 1, “PEP” means polyether polyol, “POP” means polyolefin polyol, “PEP / POP” means the ratio of polyether polyol to polyolefin polyol, “%POP” means the weight percent of the polyolefin polyol present in the TP, “HS” means the hard segment content of the TPU, “CE” means the chain extender, “A” means the Shore A hardness measured according to ASTM D2240, “R%” means the rebound measured according to ASTM D2632, “PBD” refers to an unsaturated polybutadiene with number average molecular weight of 2000 g / mol (Krasol® LBH P-2000 made by Cray Valley), “HPBD” refers to a hydrogenated polybutadiene with number average molecular weight of 2000 g / mol (Krasol® HLBH P-2000 made by Cray Valley), “BDO” refers to 1,4 butanediol, “PTMEG” refers to polytetramethylene ether glycol, and “P3OG” refers to polytrimethylene ether glycol.4839-01Table 1

[0104] Comparative Example 1 (“CE1”) was made using the “one-shot” process, where the reactants, (unsaturated polybutadiene, methylene diphenyl diisocyanate, and 1,4 butanediol) are added to an extruder reactor and reacted. Unsaturated polybutadiene diol with number average molecular weight of 2000 g / mol (Krasol® LBH P-2000 made by Cray Valley), UV additives and antioxidants were thoroughly mixed in a polyol tank at 120 °C. 1,4 butanediol was used as chain extender and methylene diphenyl diisocyanate (MDI) was used as diisocyanate, which were separately preheated to 120 °C. The reactive components were reacted in a reactive extruder with the aid of a catalyst. The hard segment content of the TPU was set at 47% and the Isocyanate Index was set to 1.00. The TPU was formed in the extruder, the extrudate was cut into pellets, dried and aged at appropriate temperature to complete the reaction.

[0105] Comparative Example 2 (“CE2”) was made using the “one-shot” process, where the reactants, (hydrogenated polybutadiene and polyether polyol, methylene diphenyl diisocyanate and 1,4 butanediol) are added to an extruder reactor and reacted. A polyol blend was prepared by mixing polytetramethylene ether glycol with number average molecular weight of 2000 g / mol with hydrogenated polybutadiene diol with number average molecular weight of 20004839-01 g / mol (Krasol® HLBH P-2000 made by Cray Valley) at ratio of 75 / 25 respectively and heated up to 120 °C. In addition, UV additives and antioxidants were thoroughly mixed in the polyol blend. 1,4 butanediol was used as chain extender, and methylene diphenyl diisocyanate (MDI) used as diisocyanate were separately preheated to 120 °C. The reactive components were reacted in a reactive extruder with the aid of a catalyst. The hard segment content of the TPU was set at 36% and the Isocyanate Index was set to 1.00. The TPU was formed in the extruder, the extrudate was cut into pellets, dried and aged at appropriate temperature to complete the reaction.

[0106] Comparative Example 3 (“CE3”) was made using a procedure similar to that of CE2.The polyol blend of CE3 was polytetramethylene ether glycol with number average molecular weight of 1000 g / mol with unsaturated polybutadiene diol with number average molecular weight of 2000 g / mol (Krasol® LBH P-2000 made by Cray Valley) at ratio of 75 / 25 respectively. The TPU hard segment was set to 36% with Isocyanate Index of 1.00.

[0107] Comparative Examples 4 through 6 (“CE4”, “CE5”, and “CE6”) were made using a procedure similar to that of CE1. The polyol for these three examples was selected from only polyether group and no polyolefin polyol was included. The hard segment content and polyol molecular weight are shown in Table 1. The Isocyanate Index for all reactions were kept at 1.00.

[0108] Examples 7 through 11 (“EX7” to “EXH”, respectively) were made using a procedure similar to that of CE2. The polyol blend of these examples was polytetramethylene ether glycol with number average molecular weight of 2000 g / mol with unsaturated polybutadiene diol with number average molecular weight of 2000 g / mol (Krasol® LBH P- 2000 made by Cray Valley). The difference between examples 7 through 11 is the ratio of polyether to polybutadiene in polyol blend and hard segment content of TPU, which are shown in Table 1.

[0109] Example 12 (“EX12”) was made using a procedure similar to that of CE2. The polyol blend of this example was bio-based polytrimethylene ether glycol with number average molecular weight of 2000 g / mol with unsaturated polybutadiene diol with number average molecular weight of 2000 g / mol (Krasol® LBH P-2000 made by Cray Valley) at ratio of 80 / 20 respectively. The TPU hard segment was set to 37% with Isocyanate Index of 1.00.4839-01

[0110] Example 13 (“EX13”) was made using a procedure similar to that of CE12. The polyol blend of this example was bio based polytrimethylene ether glycol with number average molecular weight of 2700 g / mol with unsaturated polybutadiene diol with number average molecular weight of 2000 g / mol (Krasol® LBH P-2000 made by Cray Valley) at ratio of 80 / 20 respectively. The TPU hard segment was set to 37% with Isocyanate Index of 1.00.

[0111] The TPUs of CE1, CE4, CE5, and CE6 demonstrate that, without having a polyol blend, high rebound (>50%) cannot be achieved for a solid TPU at a hardness level of interest. CE2, when compared with EX8, demonstrates that a hydrogenated polybutadiene does not result in a high rebound TPU. CE3, when comparted with EX8, demonstrates that a polyether polyol molecular weight of higher than 1,000 g / mol is desirable to achieve a solid TPU having a high rebound.

[0112] Certain of the TPU examples above were used to make foams as follows: The TPU pellets were fed into physical foam injection molding machine. The physical foam injection machine is equipped with heating zones and gas injection into the extruder and mixing zone for gas-polymer mixing. The TPU pellets melt in the heating zone due to shear and barrel temperature ranging from 180 °C to 215 °C producing a molten TPU composition. In the mixing zone of the extrusion process, N2 gas at high pressure (-170 bar) was added to the molten TPU and mixed in the special mixing zone of the extruder. The blend was then injected into a mold. Upon pressure drop and / or cooling, gas / TPU blend expands and solidifies to a foamed article in the shape of the predetermined mold. Table 2 shows the identities and physical properties of the foams so-produced. In table 2, “C” refers to Asker C durometer hardness (also referred to as Shore C hardness) determined according to ASTM D2240, “SG” refers to the specific gravity determined according to ASTM D792, “VR” refers to vertical rebound % determined according to ASTM D2632 using a foam specimen having a thickness of 20 mm, “CS” refers to compression set % determined according to ASTM D395B for 6 hours using a test specimen according to ASTM D395-18 with the sample being a cuboid of 25.4 mm by 25.4 mm and a thickness of 20 mm, and “TBD” means that data was not available yet.4839-01Table 2

[0113] CE20, CE21, and CE22 are made from the TPU of CE4, and show that, at various specific gravities, these foams have lower than 50% rebound and higher than 35% compression set, which results in undesirable foams. EX14 through EX19 show that foams made from the TPUs of EX9, EX10, and EX12 demonstrate rebound of 55% or higher and / or compression set of less than 35% at varying specific gravities.

[0114] Except in the Examples, or where otherwise explicitly indicated or required by context, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word “about”. As used herein, the term “about” means that a value of a given quantity is within ±20% of the stated value. In other embodiments, the value is within ±15% of the stated value. In other embodiments, the value is within ±10% of the stated value. In other embodiments, the value is within ±5% of the stated value. In other embodiments, the value is within ±2.5% of the stated value. In other embodiments, the value is within ±1% of the stated value. In other embodiments, the value is within a range of the explicitly-described value which would be understood by those of ordinary skill, based on the disclosures provided4839-01 herein, to perform substantially similarly to compositions including the literal amounts described herein.

[0115] It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined, and that any amount within a disclosed range is contemplated to provide a minimum or maximum of a narrower range in alternative embodiments (with the proviso, of course, that the minimum amount of a range must be lower than the maximum amount of the same range). Similarly, the ranges and amounts for each element of the subject matter disclosed herein may be used together with ranges or amounts for any of the other elements.

[0116] While certain representative embodiments and details have been shown for the purpose of illustrating the subject matter disclosed herein, it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the scope of the subject matter. In this regard, the scope of the invention is to be limited only by the following claims.

Claims

4839-01What is claimed is:

1. A composition comprising a microcellular foam comprising a thermoplastic polyurethane copolymer comprising a reaction product of the following reactants: (a) at least one diisocyanate; (b) at least one chain extender; and (c) a polyol blend comprising at least one polyether polyol and at least one polyolefin polyol; wherein the at least one polyolefin polyol makes up from 10 to 40 weight percent of the polyol blend, based on the total weight of the polyol blend; wherein the at least one polyolefin polyol is present in the thermoplastic polyurethane copolymer in an amount of from 5 to 25 weight percent, based on the total weight of the thermoplastic polyurethane copolymer; and wherein the thermoplastic polyurethane copolymer has a hard segment content of from 25 to 45 weight percent, based on the total weight of the thermoplastic polyurethane copolymer.

2. The composition of claim 1, wherein: (i) the at least one polyolefin polyol comprises at least one unsaturated polybutadiene polyol; (ii) the at least one polyolefin polyol has an average functionality of from 1.8 to 2.2; and / or (iii) the at least one polyolefin polyol has a number average molecular weight of from 1,000 to 2,500 g / mol.

3. The composition of either claim 1 or claim 2, wherein the at least one poly ether polyol comprises at least one polyol of the general formula HO-(CxO)n-H, wherein x is an integer from 2 to 6, and wherein n is an integer selected to provide a polyol with a number average molecular weight of from 1,500 to 3,000 g / mol, optionally wherein x is 3 or 4 and n is selected to provide a polyol with a number average molecular weight of from 1,500 to 2,000 g / mol.

4. The composition of any one of claims 1 to 3, wherein the at least one diisocyanate comprises at least one of methylene diphenyl diisocyanate, hexamethylene diisocyanate, methylene bis(4-cyclo-hexylisocyanate), dicyclohexylmethane 4,4’-diisocyanate, or hydrogenated methylene diphenyl diisocyanate.

5. The composition of any one of claims 1 to 4, wherein: (i) the at least one chain extender comprises at least one linear diol of the general formula CyH(2y+2)O2, wherein y is an integer from 2 to 12; and / or (ii) the at least one chain extender comprises at least one of ethylene glycol, 1,3 propanediol, 1,4 butanediol, 1,5 pentanediol, 1,6 hexanediol, 1,7 heptane diol, 1,8 octane diol, 1,9 nonane diol, 1,10 decanediol, 1,12 dodecane diol, benzene-1,4 diol, or benzene 1,3 diol.4839-016. The composition of any one of claims 1 to 5, wherein the polyol blend is a fully miscible blend at a temperature of 90 °C or greater, optionally wherein the polyol blend is a fully miscible blend at a temperature of from 90 to 150 °C.

7. The composition of any one of claims 1 to 6, wherein the amount of the at least one polyether polyol in the polyol blend is higher than the amount of polyolefin polyol in the polyol blend.

8. The composition of any one of claims 1 to 7, wherein: (i) the Isocyanate Index of the thermoplastic polyurethane copolymer is from 0.95 to 1.05; (ii) the thermoplastic polyurethane copolymer has a hardness of from 75 to 90 A, as measured by ASTM D2240; and / or (iii) the thermoplastic polyurethane copolymer has a rebound of at least 50%, as measured by ASTM D2632.

9. A microcellular foam article comprising the composition of any one of claims 1 to 8.

10. The microcellular foam article of claim 9, wherein: (i) the article has an Asker C durometer hardness of from 35 to 55, as measured by ASTM D2240; (ii) the article has a rebound of at least 55%, as measured by ASTM D2632 using a foam specimen having a thickness of 20 mm; (iii) the article has a specific gravity of from 0.15 to 0.25, as measured by ASTM D792; and / or (iv) the article has a compression set of less than 35%, as measured by ASTM D395B at 50 °C for 6 hours using a test specimen according to ASTM D395-18 with the sample being a cuboid of 25.4 mm by 25.4 mm and a thickness of 20 mm.

11. A method of making a microcellular foam article comprising: a. providing particles of a thermoplastic polyurethane copolymer comprising a reaction product of: (a) at least one diisocyanate; (b) at least one chain extender; and (c) a polyol blend comprising at least one polyether polyol and at least one polyolefin polyol; wherein the at least one polyolefin polyol makes up from 10 to 40 weight percent of the polyol blend, based on the total weight of the polyol blend; wherein the at least one polyolefin polyol is present in the thermoplastic polyurethane copolymer in an amount of from 5 to 25 weight percent, based on the total weight of the thermoplastic polyurethane copolymer; and wherein the thermoplastic polyurethane copolymer has a hard segment content of from 25 to 45 weight percent, based on the total weight of the thermoplastic polyurethane copolymer;4839-01 b. melting the particles in a melting zone of a physical injection molding apparatus to create a molten thermoplastic polyurethane composition; c. mixing the molten thermoplastic polyurethane composition with a blowing agent in a mixing zone of the physical injection molding apparatus to create a mixture of the molten thermoplastic polyurethane composition and the blowing agent; and d. injecting the mixture into a mold, during and / or after which it expands and / or cools to create the microcellular foam article.

12. The method of claim 11, wherein: (i) the at least one polyolefin polyol comprises at least one unsaturated polybutadiene polyol; (ii) the at least one polyolefin polyol has an average functionality of from 1.8 to 2.2; and / or (iii) the at least one polyolefin polyol has a number average molecular weight of from 1,000 to 2,500 g / mol.

13. The method of either claim 11 or claim 12, wherein the at least one polyether polyol comprises at least one polyol of the general formula HO-(CxO)n-H, wherein x is an integer from 2 to 6, and wherein n is an integer selected to provide a polyol with a number average molecular weight of from 1,500 to 3,000 g / mol, optionally wherein x is 3 or 4 and n is selected to provide a polyol with a number average molecular weight of from 1,500 to 2,000 g / mol.

14. The method of any one of claims 11 to 13, wherein the at least one diisocyanate comprises at least one of methylene diphenyl diisocyanate, hexamethylene diisocyanate, methylene bis(4-cyclo-hexylisocyanate), dicyclohexylmethane 4,4’-diisocyanate, or hydrogenated methylene diphenyl diisocyanate.

15. The method of any one of claims 11 to 14, wherein: (i) the at least one chain extender comprises at least one linear diol of the general formula CyH(2y+2)O2, wherein y is an integer from 2 to 12; and / or (ii) the at least one chain extender comprises at least one of ethylene glycol, 1,3 propanediol, 1,4 butanediol, 1,5 pentanediol, 1,6 hexanediol, 1,7 heptane diol, 1,8 octane diol, 1,9 nonane diol, 1,10 decanediol, 1,12 dodecane diol, benzene-1,4 diol, or benzene 1,3 diol.

16. The method of any one of claims 1 1 to 15, wherein the polyol blend is a fully miscible blend at a temperature of 90 °C or greater, optionally wherein the polyol blend is a fully miscible blend at a temperature of from 90 to 150 °C.4839-0117. The method of any one of claims 1 1 to 16, wherein the amount of the at least one polyether polyol in the polyol blend is higher than the amount of polyolefin polyol in the polyol blend.

18. The method of any one of claims 11 to 17, wherein: (i) the Isocyanate Index of the thermoplastic polyurethane copolymer is from 0.95 to 1.05; (ii) the thermoplastic polyurethane copolymer has a hardness of from 75 to 90 A, as measured by ASTM D2240; and / or (iii) the thermoplastic polyurethane copolymer has a rebound of at least 50%, as measured by ASTM D2632.

19. The method of any one of claims 11 to 18, wherein the blowing agent is nitrogen gas or supercritical carbon dioxide.

20. A microcellular foam article made according to the method of any one of claims 11 to 19.

21. The microcellular foam article of claim 20, wherein: (i) the article has an Asker C durometer hardness of from 35 to 55, as measured by ASTM D2240; (ii) the article has a rebound of at least 55%, as measured by ASTM D2632 using a foam specimen having a thickness of 20 mm; (iii) the article has a specific gravity of from 0.15 to 0.25, as measured by ASTM D792; and / or (iv) the article has a compression set of less than 35%, as measured by ASTM D395B at 50 °C for 6 hours using a test specimen according to ASTM D395-18 with the sample being a cuboid of 25.4 mm by 25.4 mm and a thickness of 20 mm.

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