Non-softening thermoplastic polyurethane

Abstract

The non-softening thermoplastic polyurethane (TPU) compositions described herein have good rebound resilience while maintaining a good combination of other properties, including hardness, low-temperature flexibility, abrasion resistance, weather resistance, low density, and combinations thereof. The degree of softening is independent of the hardness of the TPUs of the disclosed technology. This combination of properties allows the TPU compositions described herein to be useful materials in applications where polyamide copolymer (COPA) and / or polyether block amide (PEBA) materials have traditionally been used more than TPUs.

Description

[Technical Field]

[0001] In one aspect, the present technology relates to thermoplastic polyurethane (TPU) compositions that have the properties of non-softening and wet flexibility. This combination of properties makes the TPU compositions described herein useful for applications where polyamide copolymer (COPA) and / or polyether block amide (PEBA) materials have traditionally been used more than TPUs, particularly medical applications where physical properties, chemical stability, and compatibility with the body environment are important. [Background technology]

[0002] Thermoplastic polymers, copolymers, and polymer blends are widely used in the manufacture of medical devices, including a wide range of long-term and short-term implant devices. Many polymers and polymer blends used in medical devices have specific physical and chemical properties that make them particularly suitable for intracorporeal applications. Preferred chemical, physical, and thermomechanical properties depend on the specific function, the type of tissue, cell, or fluid that will contact the medical device, and the acceptable or desired manufacturing process. Key considerations when selecting a polymer for a medical device include the polymer's chemical stability, particularly hydrolytic stability, the polymer's toxicity, and the degree of interaction between the tissue or blood and the polymer. Furthermore, the polymer or polymer blend should meet all physical requirements related to the function of the medical device, including strength, compliance, stiffness, flexibility, and resilience.

[0003] Certain medical devices, such as catheters, represent a particularly large class of medical devices used in a variety of internal applications. Typically, a catheter body is formed from one type of polymer, although two or more types may be incorporated into the catheter body to provide a device that meets the physical and chemical requirements of the catheter. Certain types of catheters are widely utilized in a variety of procedures and are physically designed to be maneuvered through tortuous fluid pathways within the body to a preselected site.

[0004] To safely manipulate a catheter into place, the material used to manufacture the device should be flexible enough and have sufficient bending stiffness to avoid perforating or otherwise damaging body tissue. On the other hand, excessive softness or flexibility of the catheter material makes it difficult to manipulate the catheter through the fluid pathways after insertion. The material should have a combination of mechanical properties that allow the device to bend and flex through the body's fluid pathways without causing damage.

[0005] Thermoplastic polyurethanes have many mechanical properties that make them attractive for the manufacture of medical devices, but it is known that TPU compositions having aromatic or cycloaliphatic isocyanates in the hard segment often exhibit softening when subjected to the aqueous environments found in the body and therefore are not good candidates for certain applications that require maintaining sufficient hardness, flexibility, and maneuverability in these environments. Therefore, COPA and / or PEBA materials have often been used in place of TPU for such applications.

[0006] Thus, there continues to be a need for non-softening TPU compositions that can provide high stiffness, elasticity, resilience, and flexibility, or any combination thereof, for implantation within a mammalian body environment. Summary of the Invention [Means for solving the problem]

[0007] According to one aspect of the present technology, there is provided a non-softening thermoplastic polyurethane (TPU) composition that exhibits good mechanical properties such as flexibility, maneuverability, and stiffness that are at least comparable to PEBA and COPA materials.

[0008] In one aspect, the techniques of the present disclosure include:

[0009] (a) at least one isocyanate-terminated low free polyurethane prepolymer (briefly "prepolymer") composition prepared from the reaction of at least one polyisocyanate component (i) and at least one polyol component (ii), wherein the low free polyurethane prepolymer composition comprises greater than about 0 wt.% to about 1 wt.% or less, or about 0.05 wt.% to about 0.75 wt.% or less, or about 0.1 wt.% to about 0.5 wt.% or less of residual polyisocyanate components;

[0010] (b) at least one linear aliphatic polyisocyanate, wherein the weight ratio of the at least one aliphatic polyisocyanate to the low free polyurethane prepolymer ranges from about 10:1 to about 1:10; and

[0011] (c) at least one optional polyol component in the range of 0 wt. % to about 80 wt. % of the total weight of the thermoplastic polyurethane; and

[0012] (d) a chain extender component comprising: (iii) a first chain extender selected from at least one linear unsubstituted alkanediol containing from about 2 to about 20 carbon atoms; and (iv) a second chain extender selected from at least one cycloaliphatic diol, or at least one aliphatic branched short-chain diol, or at least one dianhydrohexitol diol, wherein the weight ratio of the first chain extender to the second chain extender is in the range of from about 1:19 to about 19:1.

[0013] In one aspect, the techniques of the present disclosure include:

[0014] (a) at least one isocyanate-terminated low free polyurethane prepolymer (briefly "prepolymer") composition prepared from the reaction of at least one aliphatic diisocyanate component (i) and at least one polyether polyol component (ii), wherein the low free polyurethane prepolymer composition comprises greater than about 0 wt.% to about 1 wt.% or less, or about 0.05 wt.% to about 0.75 wt.% or less, or about 0.1 wt.% to about 0.5 wt.% or less of residual polyisocyanate components;

[0015] (b) at least one linear aliphatic polyisocyanate, wherein the weight ratio of the at least one linear aliphatic polyisocyanate to the low free polyurethane prepolymer is in the range of from about 10:1 to about 1:10;

[0016] (c) at least one optional polyol component in the range of 0 wt. % to about 80 wt. % of the total weight of the thermoplastic polyurethane; and

[0017] (d) a chain extender component comprising: (iii) a first chain extender selected from at least one linear unsubstituted alkanediol containing from about 2 to about 20 carbon atoms; and (iv) a second chain extender selected from at least one alicyclic diol, wherein the weight ratio of the first chain extender to the second chain extender is in the range of from about 1:19 to about 19:1.

[0018] In one aspect, the techniques of the present disclosure include:

[0019] (a) at least one isocyanate-terminated low free polyurethane prepolymer composition prepared by the reaction of (i) 1,6-hexamethylene diisocyanate with (ii) polytetramethylene ether glycol (PTMEG), wherein the low free polyurethane prepolymer composition comprises greater than about 0 wt.% to about 1 wt.% or less, or about 0.05 wt.% to about 0.75 wt.% or less, or about 0.1 wt.% to about 0.5 wt.% or less of residual polyisocyanate components;

[0020] (b) at least one linear aliphatic polyisocyanate selected from 1,6-hexamethylene diisocyanate, wherein the weight ratio of the 1,6-hexamethylene diisocyanate to the low free polyurethane prepolymer is in the range of from about 10:1 to about 1:10;

[0021] (c) at least one optional polyol component in the range of 0 wt. % to about 80 wt. % of the total weight of the thermoplastic polyurethane; and

[0022] (d) a chain extender component comprising: (iii) a first chain extender comprising 1,4-butanediol; and (iv) a second chain extender comprising 1,4-cyclohexanedimethanol, wherein the weight ratio of the first chain extender to the second chain extender is in the range of about 1:19 to about 19:1.

[0023] In one aspect, the non-softening TPU compositions of the present technology are useful as materials for applications where polyamide copolymer (COPA) and / or polyether block amide (PEBA) materials have traditionally been used, particularly medical applications where physical properties, chemical stability, and compatibility in the body environment are important.

[0024] In one aspect, the technology of the present disclosure provides a method for producing a cellular membrane comprising:

[0025] a) a Shore D hardness of about 20 to about 75, as measured by ASTM D2240;

[0026] b) a dry flexural modulus of about 4,000 to about 90,000 psi as measured by ASTM D790;

[0027] c) a wet flexural modulus of about 3,000 to about 50,000 psi as measured by ASTM D790;

[0028] d) an elongation at break of about 300 to about 750 percent as measured by ASTM D412;

[0029] e) a tensile strength of about 5,000 to about 10,000 psi as measured by ASTM D412; and

[0030] f) a rebound recovery rate of about 40 to about 65 percent as measured by ASTM D2632.

[0031] In one aspect, the TPU compositions of the disclosed technology provide % softening of 20% or less while maintaining enhanced dry flexural modulus, wet flexural modulus, tensile strength, and / or rebound resilience at comparable Shore D durometer values.

[0032] In an embodiment, the TPU composition of the disclosed technology further comprises pigments, UV stabilizers, UV absorbers, antioxidants, lubricants, heat stabilizers, hydrolysis stabilizers, crosslinking activators, flame retardants, layered silicates, fillers, colorants, toughening agents, adhesion promoters, impact modifiers, radiopaque agents, antimicrobial agents, and mixtures thereof.

[0033] In one aspect, the non-softening TPU compositions of the disclosed technology are suitable for the manufacture of medical articles suitable for implantation in a mammalian body.

[0034] In one aspect, non-limiting examples of medical articles made from the TPU compositions of the disclosed technology include a pacemaker head, an angiography catheter, an angioplasty catheter, an epidural catheter, a thermodilution catheter, a urinary catheter, a catheter connector, medical tubing, intravenous tubing, cartilage replacement, or a joint replacement.

[0035] The disclosed technology provides a process for preparing the non-softening thermoplastic polyurethane composition disclosed herein, comprising: (I)

[0036] (a) at least one isocyanate-terminated low free polyurethane prepolymer composition prepared from the reaction of at least one polyisocyanate component (i) and at least one polyol component (ii), wherein the low free polyurethane prepolymer composition comprises greater than about 0% to about 1% by weight of residual polyisocyanate components;

[0037] (b) at least one linear aliphatic polyisocyanate, wherein the weight ratio of the at least one aliphatic polyisocyanate to the low free polyurethane prepolymer ranges from about 10:1 to about 1:10; and

[0038] (c) at least one polyol component in the range of 0 wt. % to about 80 wt. % of the total weight of the thermoplastic polyurethane; and

[0039] (d) reacting a mixture comprising: (iii) a first chain extender selected from at least one linear unsubstituted alkanediol containing from about 2 to about 20 carbon atoms; and (iv) a chain extender component comprising: at least one cycloaliphatic diol, or at least one aliphatic branched short chain diol, or at least one dianhydrohexitol diol; wherein the weight ratio of the first chain extender to the second chain extender is in the range of from about 1:19 to about 19:1.

[0040] The disclosed technology provides a process further comprising the step of: (II) mixing the non-softening thermoplastic polyurethane composition prepared in step (I) with one or more additional additives selected from pigments, UV stabilizers, UV absorbers, antioxidants, lubricants, heat stabilizers, hydrolysis stabilizers, crosslinking activators, flame retardants, layered silicates, fillers, colorants, toughening agents, adhesion promoters, impact modifiers, radiopaque agents, antimicrobial agents, and mixtures thereof. [Brief explanation of the drawings]

[0041] [Figure 1] 1 depicts a plot of Shore D durometer (x-axis) versus percent softening (y-axis) for selected TPU compositions of the disclosed technology. [Figure 2] 1 depicts a plot of Shore D durometer hardness values ​​(x-axis) versus percent softening (y-axis) for selected TPU compositions of the disclosed technology relative to benchmark polymers and comparative TPU samples. DETAILED DESCRIPTION OF THE INVENTION

[0042] Various aspects, features, and embodiments of the disclosed techniques are described below by way of non-limiting example.

[0043] The non-softening TPU compositions of the disclosed technology may suitably comprise, consist of, or consist essentially of the components, elements, and process delineations described herein. The disclosed technology illustratively disclosed herein may be suitably practiced in the absence of any element not specifically disclosed herein.

[0044] In all aspects of the present disclosure, all percentages are calculated by weight of the total composition unless otherwise specified. All ratios are expressed as weight ratios. All numerical ranges for amounts are inclusive and combinable unless otherwise specified.

[0045] For selected embodiments and aspects of the disclosed technology, overlapping weight ranges are expressed for the various components and ingredients that may be included in the disclosed compositions, but the amount of each component in the disclosed compositions is selected from the disclosed ranges such that the sum of all components or ingredients in the composition totals 100 weight percent. The amount used will vary depending on the purpose and characteristics of the desired product and can be readily determined by one of ordinary skill in the art.

[0046] The term "non-softening" (expressed as % softening) means that the TPU compositions of the disclosed technology are resistant to softening when exposed to the body environment over time. % softening is calculated from the following formula (see methodology in Examples 7-12): Softening% = [Flexural modulus 乾燥 -Flexural modulus 湿潤 ] x 100 / flexural modulus 乾燥

[0047] "Low free" means that the polyurethane prepolymer (a) of the technology of the present disclosure contains more than about 0 wt % to about 1 wt % or less of unreacted (residual) polyisocyanate used to prepare the prepolymer, or about 0.05 wt % or less to about 0.75 wt % or less, or about 0.1 wt % or less to about 0.5 wt % or less.

[0048] The technology of the present disclosure is

[0049] (a) at least one isocyanate-terminated low free polyurethane prepolymer composition prepared from the reaction of at least one polyisocyanate component (i) and at least one polyol component (ii), the low free polyurethane prepolymer composition comprising from greater than 0 wt% to about 1 wt% or less, or from about 0.05 wt% or less to about 0.75 wt% or less, or from about 0.1 wt% or less to about 0.5 wt% or less of a residual polyisocyanate (e.g., diisocyanate) component, based on the total weight of the low free polyurethane prepolymer, the amount of the low free polyurethane prepolymer ranging from about 1 to about 80 wt%, or from about 15 to about 50 wt%, based on the total weight of the thermoplastic polyurethane;

[0050] (b) at least one linear aliphatic polyisocyanate, wherein the weight ratio of the at least one aliphatic polyisocyanate to the low free polyurethane prepolymer ranges from about 10:1 to about 1:10, or from about 1:1 to about 1:2;

[0051] (c) at least one polyol component in the range of from 0% to about 5% to about 80% by weight of the total weight of the thermoplastic polyurethane;

[0052] (d) a chain extender component comprising: (iii) a first chain extender selected from at least one linear unsubstituted alkanediol containing from about 2 to about 20 carbon atoms; and (iv) a second chain extender selected from at least one cycloaliphatic diol, or at least one aliphatic branched short-chain diol, or at least one dianhydrohexitol diol, wherein the weight ratio of the first chain extender to the second chain extender is in the range of from about 1:19 to about 19:1, or from about 1:1 to about 10:1, or from about 2:1 to about 5:1.

[0053] Isocyanate-terminated low-free polyurethane prepolymer (component (a)) The at least one isocyanate-terminated low free polyurethane prepolymer composition (polyurethane prepolymer) used in preparing the non-softening TPU composition of the disclosed technology is prepared from the reaction of a stoichiometric excess of at least one polyisocyanate component (i) and at least one polyol component (ii) containing at least two hydroxyl groups.

[0054] In one embodiment, the at least one isocyanate-terminated low free polyurethane prepolymer composition is the reaction product of a stoichiometric excess of a diisocyanate component and a diol component.

[0055] Polyurethane prepolymer reaction products include oligomers and so-called "perfect" prepolymers. The required high oligomer content of the prepolymer composition can be expressed in terms of its content of a 2:1 stoichiometric adduct of diisocyanate and polyol, which should be greater than 20% by weight, or conversely, less than 75% by weight, based on the total weight of the prepolymer composition. 2:1 stoichiometric adducts of diisocyanates and at least one polyol ("full prepolymers") and processes for preparing them are widely known and described in the art, for example, in EP 0288823(A1), EP 0370408(A1), EP 0370392(A1), EP 0827995(A1), EP 1237967(A1), EP 1237971(A1), EP 1249460(A1), EP 1253159(A1), EP 1499653(A1), and EP 1553118(A1), which are incorporated herein by reference.

[0056] The 2:1 stoichiometric adduct of a diisocyanate and at least one polyol of the disclosed technology is the stoichiometric end-capping product of one polyol molecule (B) with two diisocyanate molecules (A). The stoichiometric ratio of diisocyanate and polyol in the reaction product is 2:1 in the case of a diol (difunctional polyol (B)). A perfect prepolymer is essentially an adduct containing only one molecule of polyol (B) in each prepolymer molecule A:B:A (or A2B).

[0057] The oligomers of prepolymer composition (a) are any species with a composition greater than a perfect 2:1 molecular ratio (A:B:A, i.e., a diurethane), such as 3:2 (A:B:A:B:A, i.e., a triurethane), or 4:3 (A:B:A:B:A:B:A, i.e., a tetraurethane) for the difunctional polyol (B).

[0058] In one embodiment, the prepolymer composition (1) comprises less than 75 wt%, or less than 73 wt%, or less than 70 wt%, based on the total weight of the polyurethane prepolymer, of a 2:1 stoichiometric adduct of a diisocyanate and a polyol, and (2) comprises greater than 0 wt% to less than 1.0 wt% of unreacted, and therefore free, diisocyanate monomer. In one embodiment, the technology of the present disclosure requires that the diisocyanate prepolymer reaction product (1) comprises greater than 30 wt% of a 2:1 stoichiometric adduct of a diisocyanate and at least one polyol, and less than 75 wt%, or less than 73 wt%, or less than 70 wt% of a 2:1 stoichiometric adduct of a diisocyanate and at least one polyol, and (2) contains greater than 0 wt% and less than 0.1 wt% of unreacted diisocyanate monomer.

[0059] In one embodiment, the polyurethane prepolymer reaction product contains free prepolymer NCO functional groups in the range of 0.2 to 15 wt%, or about 0.5 to about 8 wt%, or about 5 to about 7 wt%. Free NCO content is typically determined in weight percent according to ASTM D1638-70. In one embodiment, the polyurethane prepolymer composition of the disclosed technology contains free prepolymer NCO groups in the range of about 0.2 to about 15 wt%, or about 0.5 to about 8 wt%, or about 5 to about 7 wt%, based on the weight of the polyurethane prepolymer, and greater than 0 wt% to less than 1.0 wt% of unreacted (residual) diisocyanate monomer. In one embodiment, the unreacted (residual) diisocyanate monomer is less than about 0.5 wt%, or less than about 0.1 wt%, based on the weight of the polyurethane prepolymer.

[0060] In one aspect of the present technology, the polyurethane prepolymer comprises, based on the total weight of the prepolymer, at least about 30% by weight of a 2:1 stoichiometric adduct of a diisocyanate and at least one polyol, and less than about 75% by weight of a 2:1 stoichiometric adduct of a diisocyanate and at least one polyol, or less than about 75% by weight of a 2:1 stoichiometric adduct of a diisocyanate and at least one polyol, or less than about 70% by weight of a 2:1 stoichiometric adduct of a diisocyanate and at least one polyol, or less than about 65% by weight of a 2:1 stoichiometric adduct of a diisocyanate and at least one polyol, or conversely, at least 20% by weight of an oligomer, preferably at least 25% by weight of an oligomer, more preferably at least 30% by weight of an oligomer, and even more preferably at least 35% by weight of an oligomer.

[0061] Polyurethane prepolymer polyisocyanate (component (i)) The polyisocyanate component of the technology of the present disclosure is not particularly limited and includes aromatic, aliphatic (alicyclic and linear aliphatic) polyisocyanates, and mixtures thereof. In one embodiment, the polyisocyanate component used to prepare the prepolymer of the technology of the present disclosure is a diisocyanate. Non-limiting examples of suitable diisocyanates include aromatic diisocyanates such as 4,4'-methylenebis-(phenylisocyanate) (MDI), m-xylylene diisocyanate (XDI), phenylene-1,4-diisocyanate (PPDI), 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TODI), diphenylmethane-3,3'-dimethoxy-4,4'-diisocyanate, toluene diisocyanate (TDI), and naphthalene-1,5-diisocyanate; isophorone diisocyanate; alicyclic diisocyanates such as 1,4-cyclohexyl diisocyanate (CHDI), dicyclohexylmethane-4,4'-diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (H12MDI), and 1,4-cyclohexyl diisocyanate (CHDI), and linear aliphatic diisocyanates such as 1,6-hexamethylene diisocyanate (HDI) and decane-1,10-diisocyanate, and mixtures thereof.

[0062] Polyurethane prepolymer polyol (component (ii)) The polyurethane prepolymers described herein are made using a polyol component, including polyester polyols, polyether polyols, polycarbonate polyols, polysiloxane polyols, alkoxylated polysiloxane polyols, polybutadiene polyols, and combinations thereof.

[0063] In one embodiment, the polyol is selected from hydroxyl-terminated diols, including one or more hydroxyl-terminated polyesters, one or more hydroxyl-terminated polyethers, one or more hydroxyl-terminated polycarbonates, one or more hydroxyl-terminated polysiloxanes, one or more hydroxyl-terminated polybutadienes, and mixtures thereof.

[0064] Suitable hydroxyl-terminated polyester intermediates include linear polyesters having number-average molecular weights (Mn) of about 500 to about 10,000, about 700 to about 5,000, or about 700 to about 4,000, and generally have acid numbers less than 1.3 or less than 0.5. The molecular weight is determined by assay of the terminal functional groups and is related to the number-average molecular weight. The polyester intermediates can be produced by (1) an esterification reaction of one or more glycols with one or more dicarboxylic acids or anhydrides, or (2) a transesterification reaction, i.e., the reaction of one or more glycols with esters of dicarboxylic acids. In one embodiment, a molar ratio of greater than 1 mole of glycol to acid is used to obtain linear chains with a predominance of terminal hydroxyl groups. The dicarboxylic acids of the desired polyester can be aliphatic, cycloaliphatic, aromatic, or a combination thereof. Suitable dicarboxylic acids, which may be used alone or in mixtures, generally have a total of 4 to 15 carbon atoms and include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, and the like. Anhydrides of the above dicarboxylic acids, such as phthalic anhydride and tetrahydrophthalic anhydride, may also be used. Adipic acid is a preferred acid. The glycols reacted to form the desired polyester intermediate may be aliphatic, aromatic, or a combination thereof, and may include any of the glycols described in the chain extender section above, having a total of 2 to 20 or 2 to 12 carbon atoms. Suitable examples include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanedimethanol, decamethylene glycol, dodecamethylene glycol, and mixtures thereof.

[0065] In one embodiment, the polyol component can also include one or more polycaprolactone polyester polyols. Polycaprolactone polyester polyols useful in the technology described herein include polyester diols derived from caprolactone monomers. The polycaprolactone polyester polyols are terminated with primary hydroxyl groups. Suitable polycaprolactone polyester polyols can be made from ε-caprolactone and a difunctional initiator, such as diethylene glycol, 1,4-butanediol, or any of the other glycols and / or diols listed herein. In one embodiment, the polycaprolactone polyester polyol is a linear polyester diol derived from caprolactone monomers.

[0066] Useful examples include CAPA™ 2202A, a 2,000 number average molecular weight (Mn) linear polyester diol, and CAPA™ 2302A, a 3,000 Mn linear polyester diol, both of which are commercially available from Perstorp Polyols Inc. These materials may also be described as polymers of 2-oxepanone and 1,4-butanediol.

[0067] Polycaprolactone polyester polyols can be prepared from 2-oxepanone and a diol, where the diol can be 1,4-butanediol, diethylene glycol, monoethylene glycol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, or any combination thereof. In some embodiments, the diol used to prepare the polycaprolactone polyester polyol is linear. In some embodiments, the polycaprolactone polyester polyol is prepared from 1,4-butanediol. In some embodiments, the polycaprolactone polyester polyol has a number average molecular weight of 500 to 10,000, or 500 to 5,000, or 1,000, or even 2,000 to 4,000, or even 3,000.

[0068] Suitable hydroxyl-terminated polyether intermediates include polyether polyols derived from diols or polyols having a total of 2 to 15 carbon atoms. In some embodiments, alkyl diols or glycols are reacted with ethers containing alkylene oxides having 2 to 6 carbon atoms, typically ethylene oxide or propylene oxide, or mixtures thereof. For example, hydroxyl-functional polyethers can be produced by first reacting propylene glycol with propylene oxide and then with ethylene oxide. Primary hydroxyl groups, resulting from ethylene oxide, are preferred because they are more reactive than secondary hydroxyl groups. Useful commercially available polyether polyols include poly(ethylene glycol), which contains ethylene oxide reacted with ethylene glycol; poly(propylene glycol), which contains propylene oxide reacted with propylene glycol; and poly(tetramethylene ether glycol), which contains water reacted with tetrahydrofuran (sometimes described as polymerized tetrahydrofuran and commonly referred to as PTMEG). In some embodiments, the polyether intermediate comprises PTMEG. Suitable polyether polyols also include polyamide adducts of alkylene oxides, such as ethylenediamine adducts, which include the reaction product of ethylenediamine and propylene oxide; diethylenetriamine adducts, which include the reaction product of diethylenetriamine and propylene oxide; and similar polyamide-type polyether polyols. Copolyethers can also be utilized in the described compositions. Typical copolyethers include the reaction products of THF and ethylene oxide or THF and propylene oxide. These are available from BASF as block copolymers, PolyTHF® B, and random copolymers, PolyTHF® R.The various polyether intermediates generally have number average molecular weights (Mn), as determined by assay of the terminal functional groups, of about 300 or more, or about 500 or more, or about 700 or more, or about 1,000 or more, or about 14,500 or more, or about 2,500 or more, or about 3,000 or more, or about 5,000 or more, or about 8,000 or more, or about 10,000 or more. In some embodiments, the polyether intermediate comprises a blend of two or more different molecular weight polyethers, such as, for example, a blend of 300 Mn and 8,000 Mn PEG, or a blend of 300 Mn, 1450 Mn, and 8,000 Mn PEG.

[0069] Suitable hydroxyl-terminated polycarbonates include those prepared by reacting a glycol with a carbonate. U.S. Pat. No. 4,131,731 is incorporated herein by reference for its disclosure of hydroxyl-terminated polycarbonates and their preparation. Such polycarbonates are linear and essentially have terminal hydroxyl groups, excluding other end groups. The essential reactants are a glycol and a carbonate. Suitable glycols are selected from cycloaliphatic and aliphatic diols containing 4 to 40 and / or even 4 to 12 carbon atoms, and polyoxyalkylene glycols containing 2 to 20 alkoxy groups per molecule, each alkoxy group containing 2 to 4 carbon atoms. Suitable diols include aliphatic diols containing 4 to 12 carbon atoms, such as 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,10-decanediol, hydrogenated dilinoleyl glycol, hydrogenated dioleyl glycol, and 3-methyl-1,5-pentanediol, as well as alicyclic diols, such as 1,3-cyclohexanediol, 1,4-dimethylolcyclohexane, 1,4-cyclohexanediol, 1,3-dimethylolcyclohexane, 1,4-endomethylene-2-hydroxy-5-hydroxymethylcyclohexane, and polyalkylene glycols. The diol used in the reaction can be a single diol or a mixture of diols, depending on the properties desired in the final product. Hydroxyl-terminated polycarbonate intermediates are generally known in the art and in the literature. Suitable carbonates are selected from alkylene carbonates composed of 5- to 7-membered rings. Suitable carbonates for use herein include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-ethylene carbonate, 1,3-pentylene carbonate, 1,4-pentylene carbonate, 2,3-pentylene carbonate, and 2,4-pentylene carbonate.Also suitable herein are dialkyl carbonates, alicyclic carbonates, and diaryl carbonates. Dialkyl carbonates can contain 2 to 5 carbon atoms in each alkyl group, and specific examples include diethyl carbonate and dipropyl carbonate. Alicyclic carbonates, particularly bicyclic aliphatic carbonates, can contain 4 to 7 carbon atoms in each ring structure, and there can be one or two such structures. When one group is alicyclic, the other can be either alkyl or aryl. On the other hand, when one group is aryl, the other can be alkyl or alicyclic. Examples of suitable diaryl carbonates, which can contain 6 to 20 carbon atoms in each aryl group, are diphenyl carbonate, ditolyl carbonate, and dinaphthyl carbonate.

[0070] Suitable polysiloxane polyols include α-ω-hydroxyl- or hydroxyalkyl-terminated diols. Examples include poly(dimethylsiloxane)s terminated with hydroxyl or hydroxyalkyl end groups. In one embodiment, the polysiloxane polyol is a hydroxyl-terminated polydimethylsiloxane. In one embodiment, the polysiloxane polyol is selected from hydroxymethyl-, hydroxyethyl-, or hydroxypropyl-terminated polydimethylsiloxanes. In one embodiment, the polysiloxane polyol has a number average molecular weight ranging from about 300 to about 5,000 or from about 400 to about 3,000.

[0071] Polysiloxane polyols can be obtained by introducing alcoholic hydroxy groups into the polysiloxane skeleton through a dehydrogenation reaction between a polysiloxane hydride and an aliphatic polyhydric alcohol or a polyoxyalkylene alcohol.

[0072] In one aspect, the polysiloxane polyol is selected from one or more compounds represented by the following formula: [ka] In the formula, each R1 is independently selected from C1 to C4 alkyl, benzyl, and phenyl, a and b each independently represent an integer of 0 to 8 or 1 to 8, and c represents an integer of 3 to 50. In one embodiment, each R1 is a methyl group.

[0073] Suitable polysiloxane polyols are commercially available from Dow Chemical, Gelest, and Sigma-Aldrich.

[0074] Alkoxylated polysiloxane polyols are copolymers of dimethylsiloxane (dimethicone) modified with alkylene oxide units. The alkylene oxide units can be arranged randomly or as block copolymers. A commonly useful class of dimethicone polyols are block copolymers having terminal and / or pendant blocks of polydimethylsiloxane and blocks of polyalkylene oxide, such as polyethylene oxide, polypropylene oxide, or both. [ka] wherein each R3 is independently selected from C1-C4 alkyl, benzyl, and phenyl; OE and EO represent ethylene oxide residues (e.g., -CH2CHO-); OP and PO represent propylene oxide residues (e.g., -CH2CH2CHO- and / or -CH2CH(CH3)O-); and x is independently from about 0 to about 200, or from about 1 to about 100, or from about 2 to about 50, or from about 3 to about 25, or from about 5 to about 20, or from about 8 to about 15. y independently represents an integer ranging from about 0 to about 200, or from about 1 to about 100, or from about 2 to about 50, or from about 3 to about 25, or from about 5 to about 20, or from about 8 to about 15, provided that x and y cannot all be 0 at the same time; z independently represents an integer ranging from about 1 to about 1000, or from about 5 to about 800, or from about 10 to about 500, or from about 15 to about 200, or from about 25 to 100; and n independently represents an integer ranging from about 1 to about 4. The OE, EO, OP, and PO residues can be arranged randomly, non-randomly, or in block sequences.

[0075] In one aspect, each R3 group is methyl; x independently represents an integer ranging from about 1 to about 100, or from about 2 to about 50, or from about 3 to about 25, or from about 5 to about 20; y is 0; z represents an integer ranging from about 1 to about 100; and n represents an integer ranging from about 1 to about 4.

[0076] Alkoxylated polysiloxane polyols are disclosed in U.S. Patent No. 5,180,843, which is incorporated herein by reference. Alkoxylated polysiloxane polyols are commercially available from Lubrizol Advanced Materials, Inc. under the Silsense trade name.

[0077] Suitable polybutadiene polyols may be selected from linear or branched, hydroxyl-terminated, optionally hydrogenated, polybutadiene diols.

[0078] Among the hydroxyl-terminated polybutadiene diols useful for preparing the isocyanate-terminated low free prepolymers of the disclosed technology are those having a number average molecular weight (Mn) of from about 500 to about 10,000, or from about 800 to about 5,000, a primary hydroxyl group content of from about 0.1 to about 2.0 meq / g, or from about 0.3 to about 1.8 meq / g, a degree of hydrogenation of the olefinic moieties present of from 0 to 100 percent, and an average content of copolymerized additional monomers of from 0 to about 50 weight percent.

[0079] Hydroxyl-terminated butadiene diols average two or more primarily primary hydroxyl groups per molecule, for example, an average of about 1.7 to about 2.4 primary hydroxyl groups per molecule. In one embodiment, hydroxyl-terminated polybutadienes have an average of at least about two hydroxyl groups, with the hydroxyl groups located primarily at terminal allylic positions on the polybutadiene backbone, i.e., generally the longest hydrocarbon chain of the molecule. The "allylic" configuration means that the alpha-allylic group of the allylic alcohol, i.e., the terminal hydroxyl group of the polymer, is attached to the carbon atom adjacent to the double-bonded carbon atom.

[0080] The hydroxyl-terminated polybutadiene may also incorporate one or more other copolymerizable monomers. The total amount of copolymerized monomers does not exceed, on average, 50% by weight of the hydroxyl-terminated polybutadiene copolymer. Among the copolymerizable monomers are monoolefins and dienes such as ethylene, propylene, 1-butene, isoprene, chloroprene, 2,3-methyl-1,3-butadiene, and 1,4-pentadiene, as well as ethylenically unsaturated monomers such as acrylonitrile, methacrylonitrile, methylstyrene, methyl acrylate, methyl methacrylate, and vinyl acetate.

[0081] In one aspect of the disclosed technology, the isocyanate-terminated low free polyurethane prepolymer is end-capped with isocyanatohexyl groups.

[0082] In one aspect of the disclosed technology, an isocyanate-terminated low free polyurethane prepolymer is prepared by the reaction of 1,6-hexamethylene diisocyanate and a polyether polyol.

[0083] In one aspect of the disclosed technology, an isocyanate-terminated low free polyurethane prepolymer is prepared by the reaction of 1,6-hexamethylene diisocyanate and tetrahydrofuran.

[0084] Prepolymer preparation Methods for synthesizing isocyanate-terminated polyurethane prepolymers are well known in the art. Generally, the isocyanate-terminated, low-free-chain polyurethane prepolymers of the disclosed technology are prepared by reacting an excess of at least one polyisocyanate (component (i)) and at least one polyol (component (ii)). In one embodiment, the at least one polyisocyanate is selected from diisocyanates, and the at least one polyol is selected from diols. As previously mentioned, a 2:1 ratio of at least one diisocyanate to at least one diol is used in the reaction mixture. A stoichiometric excess of diisocyanate ensures that the diol is fully end-capped with isocyanate moieties. A reaction mixture containing at least one polyisocyanate (e.g., diisocyanate) and at least one polyol (e.g., diol) is heated at a temperature ranging from about 50 to about 150°C, or from about 60 to about 100°C, for 10 minutes to 24 hours, or from 2 to 6 hours.

[0085] The formation of the isocyanate-terminated prepolymer of the technology of the present disclosure can be achieved without using a catalyst. However, in some cases, a catalyst is optionally used depending on the application of the final product made from the polyurethane prepared using the isocyanate-terminated low-free prepolymer. In one aspect, the reaction for forming the prepolymer is not catalyzed. The use of a catalyst can result in residual catalyst in the prepolymer reaction product, which can cause toxicity problems for the medical application of TPUs that utilize such prepolymers.

[0086] The isocyanate-terminated polyurethane prepolymers of the disclosed technology are low-free residual monomer polyurethane prepolymers, meaning that the polyurethane prepolymer composition contains 1.0 wt% or less of free residual polyisocyanate (e.g., diisocyanate) monomer, based on the total weight of the polyurethane prepolymer. Unreacted diisocyanate residual monomer in the prepolymer reaction product is removed to a concentration ranging from greater than 0 wt% to about 1.0 wt% or less, or from about 0.05 to about 0.75 wt% or less, or from about 0.1 to about 0.5 wt% or less, based on the total weight of the polyurethane prepolymer.

[0087] Residual polyisocyanate monomers can be removed from polyurethane prepolymers by conventional means known in the art. For example, methods for removing residual isocyanate-containing monomers from polyurethane prepolymer compositions include, but are not limited to, wiped film evaporation, solvent-assisted distillation or co-distillation, molecular sieves, and solvent extraction. In one embodiment, distillation under reduced pressure, such as thin film or stirred film evaporation under vacuum, can be used.

[0088] The amount of free diisocyanate residual monomer in the prepolymer composition can be determined by conventional means known in the art, such as high performance liquid chromatography (HPLC) methods.

[0089] In one aspect, prepolymers of the disclosed technology and their preparation are disclosed in WO 2021 / 051039, which is incorporated herein by reference.

[0090] Thermoplastic polyurethane The TPU composition of the disclosed technology comprises (a) a mixture of at least one isocyanate-terminated low free polyurethane prepolymer as described above; (b) at least one linear aliphatic polyisocyanate, wherein the weight ratio of the at least one aliphatic polyisocyanate to the isocyanate-terminated low free polyurethane prepolymer is in the range of about 10:1 to about 1:10, or about 1:1 to about 1:2; (c) at least one polyol component in the range of 0 wt% to about 5 wt% to about 80 wt% of the total weight of the thermoplastic polyurethane; and and (d) a chain extender component comprising (iii) a first chain extender selected from at least one linear unsubstituted alkanediol containing from about 2 to about 20 carbon atoms, and (iv) a second chain extender selected from at least one cycloaliphatic diol, or at least one aliphatic branched short chain diol, or at least one dianhydrohexitol diol, wherein the weight ratio of the first chain extender to the second chain extender is in the range of from about 1:19 to about 19:1, or from about 1:1 to about 10:1, or from about 2:1 to about 5:1.

[0091] The polyurethanes of the presently disclosed technology can be prepared using various techniques known in the art. In one embodiment, a preformed isocyanate-terminated low-free polyurethane prepolymer (a) is reacted with at least one linear aliphatic polyisocyanate (b) described herein, an optional polyol (c), and a chain extender component (d) including a first chain extender and a second chain extender. An optional catalyst and other optional additive components can be added to the reaction mixture.

[0092] The preformed isocyanate-terminated low free polyurethane prepolymer (a) can be prepared as described above or can be obtained commercially. In one embodiment, the isocyanate-terminated low free polyurethane prepolymer is commercially available from Lanxess AG under the trade name Adiprene™ LFH E1192, which is a reaction product of hexamethylene diisocyanate (HDI) and a polyether polyol having a low free HDI content (less than 0.1 wt%).

[0093] In one embodiment, the preformed isocyanate-terminated low free polyurethane prepolymer (a), linear aliphatic polyisocyanate (b), optional polyol (c), chain extender component (d), and other optional additive components, when mixed, are maintained at a temperature of at least about 90° C. for at least about 10 minutes, or at least about 110° C., or at least about 120° C., or at least about 130° C., or at least about 140° C. for at least about 3 seconds to 2 hours or more, or at least about 10 minutes, or at least about 20 minutes, or at least about 30 minutes, or at least about 1 hour. In some non-limiting embodiments, when mixed, the components are maintained at a temperature of at least about 100° C., or at least about 105° C., or at least about 110° C., or at least about 125 to about 220° C. for at least about 10 minutes, at least about 20 minutes, or at least about 1 hour.

[0094] In one aspect, the isocyanate-terminated low free polyurethane prepolymer (a) is formed as described above, followed by introducing (with mixing) the linear aliphatic polyisocyanate (b), optional polyol (c), chain extender component (d), and other optional additive components into the reaction medium at the temperature ranges and for the times described in the immediately preceding paragraphs.

[0095] In one aspect, the process for producing the TPUs of the disclosed technology is what is referred to as a one-shot polymerization process. In a one-shot polymerization process, which generally occurs in situ, simultaneous reactions occur between reaction components (a), (b), optionally (c), and (d).

[0096] In one embodiment, the TPU-forming components of the disclosed technology are melt-polymerized in a suitable mixer, such as an internal mixer (e.g., a Banbury mixer), or in an extruder (e.g., a twin-screw extruder). The reaction generally begins at a temperature of about 90°C to about 200°C. As long as the reaction is exothermic, the reaction temperature generally increases to about 220°C to 250°C. If the reaction is conducted in a reaction extruder, the TPU polymer exits the extruder and is typically pelletized. Alternatively, if the reaction is conducted in a mixer or vessel, the TPU reaction product is poured into a mold block and cured. Optionally, the TPU pellets or block can be stored at an elevated temperature to continue the reaction to fully react all reaction components. The molded TPU block is typically processed into a crumb form. The TPU pellets and crumb product can be further melt-processed in an extruder (with optional additives) and molded into the final product form.

[0097] Alternatively, the TPU reaction components (including optional additives) can be polymerized in an extruder as described above and directly extruded or molded into the desired end product.

[0098] Optional Additives One or more additional additives selected from pigments, including but not limited to UV stabilizers, UV absorbers, antioxidants, lubricants, heat stabilizers, hydrolysis stabilizers, crosslinking activators, flame retardants, layered silicates, fillers, colorants, toughening agents, adhesion promoters, impact modifiers, antimicrobial agents, and mixtures thereof, may be blended into the TPU compositions of the disclosed technology.

[0099] In one embodiment, the resulting TPU has the following properties:

[0100] a) a Shore D hardness of about 20 to about 75, as measured by ASTM D2240;

[0101] b) a dry flexural modulus of about 4,000 to about 90,000 psi as measured by ASTM D790;

[0102] c) a wet flexural modulus of about 3,000 to about 50,000 psi as measured by ASTM D790;

[0103] d) an elongation at break of about 300 to about 750 percent as measured by ASTM D412;

[0104] e) a tensile strength of about 5,000 to about 10,000 psi as measured by ASTM D412;

[0105] f) A rebound recovery of about 40 to about 65 percent as measured by ASTM D2632.

[0106] Polyisocyanate (b) In one embodiment, the at least one linear aliphatic polyisocyanate (b) is a C1-C 12 The linear aliphatic diisocyanates are selected from C1 to C6. 12 Linear aliphatic diisocyanates include, but are not limited to, ethylene diisocyanate, 1,3-propane diisocyanate, 1,4-butane diisocyanate, 1,5-pentane diisocyanate, 1,6-hexane diisocyanate (hexamethylene diisocyanate or HDI), 1,8-octane diisocyanate, and 1,12-dodecane diisocyanate. The linear aliphatic diisocyanates can be used individually or in combination of two or more. More specifically, one linear aliphatic polyisocyanate can be HDI.

[0107] Polyol (c) In the preparation of the TPU of the technology of the present disclosure, the use of polyol (c) is optional. The polyol may be used in the reaction mixture in an amount ranging from about 0 to about 80 wt %, based on the total weight of the polyurethane. In one embodiment, when used in the reaction mixture, polyol (c) may be selected from any polyol known in the preparation of TPUs. In one embodiment, polyol component (c) is selected from the diol components described above for use in the preparation of the isocyanate-terminated low-free polyurethane prepolymer, such as polyether polyols, polyester polyols, polycarbonate polyols, polysiloxane polyols, polybutadiene polyols, and mixtures thereof.

[0108] In one aspect, polyol (c) is selected from poly(ethylene oxide), polyethylene glycol, poly(propylene oxide), polypropylene glycol, polytetramethylene ether glycol, and mixtures thereof, each of which has been previously described above in prepolymer polyol component (ii), the disclosure of which is incorporated herein by reference.

[0109] Chain extender (d) In preparing the TPU composition of the presently disclosed technology, the chain extender (d) includes (iii) a first chain extender selected from at least one linear unsubstituted alkanediol containing from about 2 to about 20 carbon atoms, and (iv) a second chain extender selected from at least one alicyclic diol, at least one aliphatic branched short-chain diol, or at least one dianhydrohexitol diol, wherein the weight ratio of the first chain extender to the second chain extender ranges from about 1:19 to about 19:1, or from about 1:1 to about 10:1, or from about 2:1 to about 5:1.

[0110] In one embodiment, the weight ratio of polyol component to total chain extender components (first and second) ranges from about 0 to about 20:1.

[0111] In one embodiment, the total chain extender components (first and second) comprise about 2% to 35% by weight of the total weight of the polyurethane composition.

[0112] In one embodiment, the first chain extender (iii) is selected from at least one linear, unsubstituted alkanediol containing from about 2 to about 20 carbon atoms. Exemplary first chain extenders include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol (BDO), 1,5-pentanediol, 1,6-hexanediol (HDO), 1,7-heptanediol, 1,9-nonanediol, 1,11-undecanediol, 1,12-dodecanediol, and mixtures thereof.

[0113] In one embodiment, the second chain extender is selected from at least one cycloaliphatic diol, at least one aliphatic branched short-chain diol, or at least one dianhydrohexitol diol. Exemplary cycloaliphatic diols include 2,2'-(cyclohexane-1,1-diyl)-diethanol, 4,4'-bicyclohexanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, cyclopentanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol (CHDM), 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,3-cyclododecanediol, 1,4-cyclododecanediol, 1,5-cyclododecanediol, and 1,5-cyclododecanediol. ,6-cyclododecanediol, 4,4'-isopropylidenedicyclohexanol, 1-(3-hydroxypropyl)cyclohexanol, 2-(3-hydroxypropyl)cyclohexanol, 1,4-cyclohexanediethanol, 1,4-cyclohexanediethanol, 1,2-bis(hydroxymethyl)-cyclohexane, 1,2-bis(hydroxyethyl)-cyclohexane, 4,4'-isopropylidene-biscyclohexanol, bis(4-hydroxycyclohexyl)methane, and mixtures thereof.

[0114] By aliphatic branched short-chain diol, we mean that the diol contains an aliphatic backbone of 8 or fewer carbon atoms and has at least one aliphatic side chain (or branched substituent) of at least 1 carbon atom. The aliphatic side chain can be linear or branched. In one aspect, the aliphatic backbone contains 3 to 8 carbon atoms and the aliphatic side chain is an alkyl group containing 1 to 5 carbon atoms. As is well known in chemical nomenclature, the backbone contains more carbon atoms than the side or branched chains. Exemplary aliphatic branched short-chain diols include neopentyl glycol, tripropylene glycol, e.g., [(1-methyl-1,2-ethanediyl)bis(oxy)]bispropanol, 3,3-dimethoxy-1,5-pentanediol, 2-methyl-butanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, dibutyl 1,3-propanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-cyclohexanediol, 2, Examples of branched aliphatic short-chain diols include, but are not limited to, 4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1-methyl-1,5-pentanediol, 3-tert-butyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,2-diethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,2-dibutyl-1,3-propanediol, 2,2-methyl-2,3-pentanediol, 3,3-dimethyl-1,2-butanediol, 3-ethyl-1,3-pentanediol, 2-butyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, and mixtures thereof. Specifically, the branched aliphatic short-chain diol may be 2-methyl-1,3-propanediol. Specifically, the aliphatic branched short chain diol can be 2-butyl-2-ethyl-1,3-propanediol.

[0115] Exemplary dianhydrohexitol diols include isosorbide (1,4:3,6-dianhydro-D-glucitol), isoidide (1,4:3,6-dianhydro-L-iditol), isomannide (1,4:3,6-dianhydro-D-mannitol), and mixtures thereof.

[0116] In one embodiment, the chain extender component includes a first chain extender selected from at least one linear unsubstituted alkanediol containing from about 2 to about 20 carbon atoms, and a second chain extender selected from at least one alicyclic diol. Specifically, the first chain extender can be 1,4-butanediol (BDO), and the second chain extender can be 1,3-cyclohexanedimethanol (CHDM).

[0117] In one embodiment, the first chain extender can be 1,4-butanediol (BDO), and the second chain extender can be an aliphatic branched short-chain diol. Specifically, the first chain extender can be 1,4-butanediol, and the second chain extender component can be 2-methyl-1,3-propanedio. Specifically, the first chain extender component can be 1,4-butanediol, and the second chain extender component can be 2-butyl-2-ethyl-1,3-propanediol.

[0118] The technology of the present disclosure further provides articles made with the TPU materials and / or compositions described herein. The specific types of articles or products that can be made from the TPU materials and / or compositions of the technology of the present disclosure are not limited, provided that the properties of the TPU meet the specifications required by the final product. In one embodiment, the TPUs of the technology of the present disclosure can be used in medical applications. Non-limiting examples include pacemaker heads, angiography catheters, angioplasty catheters, epidural catheters, thermodilution catheters, and urinary catheters, catheter connectors, medical tubing, cartilage replacements, hair replacements, joint replacements, and the like, as well as for personal care applications, pharmaceutical applications, health care product applications, or any of a number of other applications. In some embodiments of the technology of the present disclosure, these articles are prepared by extrusion molding, injection molding, or any combination thereof. [Example]

[0119] The technology of the present disclosure is illustrated by the following examples, which are merely for illustrative purposes and should not be considered as limiting the scope of the technology or methods by which it can be practiced. Unless otherwise specified, parts and percentages are given by weight. All weights and percentages are expressed as 100 percent active material unless otherwise specified.

[0120] Examples 1 to 6 A series of thermoplastic polymers, including those of the disclosed technology, were prepared from the components set forth in Table 1. Each of the polymers was prepared by reacting the components and then forming a test specimen by extrusion or molding. [Table 1] 1 First chain extender. 2 Second chain extender. 3Isocyanate-terminated low free prepolymer: reaction product of hexamethylene diisocyanate (HDI) and polyether polyol (Adiprene™ LFH E1192) with low free HDI content (less than 0.1 wt%). 4 BDO = 1,4-butanediol. 5 CHDM = 1,4-cyclohexanedimethanol. 6 Comparative example. 7 Pebax™ 7233—A commercially available polyether block amide sold by Arkema. 8 Aliphatic TPU. 9 H12MDI = dicyclohexylmethane-4,4'-diisocyanate. 10 Polytetramethylene ether glycol (1000Mn). 11 Aromatic TPU. 12 MDI = 4,4'-methylenebis-(phenylisocyanate). 13 Polytetramethylene ether glycol (650Mn). 14 Polytetramethylene ether glycol (1400Mn).

[0121] Examples 7 to 12 Each of the polymer samples prepared in Examples 1-6 was evaluated to verify its Shore D hardness (measured by ASTM D2240), dry flexural modulus (measured by ASTM D790), wet flexural modulus (measured by ASTM D790), and its rebound resilience (measured by ASTM D2632), elongation at break (measured by ASTM D412), tensile strength (measured by ASTM D412), rebound resilience (measured by ASTM D2632), and percent softening. Prior to Shore D hardness (ASTM D2240) and flexural modulus (ASTM D790) testing, injection-molded bar test specimens (5 inches long x 1 / 2 inch wide x 1 / 8 inch thick) were stored at room temperature for at least 5 days and then conditioned at 23 + / - 2°C and 50% RH + / - 5% for 40 hours.

[0122] Percent softening was determined by measuring the flexural modulus (at ambient room temperature (RT), 20-25°C) according to ASTM D790 for dry and wet injection molded bars (5 inches long x 1 / 2 inch wide x 1 / 8 inch thick) immersed in deionized water at 40°C for 5 days and entering the results into the following equation: Softening% = [Flexural modulus 乾燥 -Flexural modulus 湿潤 ] x 100 / flexural modulus 乾燥 The results of all studies are presented in Table 2. [Table 2] 1 Comparative example.

[0123] The results show that the TPU compositions of the disclosed technology provide better dry flexural modulus than conventional aliphatic and aromatic TPU compositions, while all other properties were comparable. The Shore D and % softening values ​​for the TPUs of Examples 7-9 of the disclosed technology are compared to the Pebax™ polymer benchmark and the comparative polymers of Examples 10, 11, and 12, including comparative aliphatic and aromatic TPUs. The % softening and Shore D values ​​for the TPUs of Examples 7-12 are plotted in Figure 1.

[0124] Examples 13 to 16 A series of thermoplastic polymers were prepared from the components listed in Table 3. [Table 3] 1 First chain extender. 2 Second chain extender. 3 Isocyanate-terminated low free prepolymer: reaction product of hexamethylene diisocyanate (HDI) and polyether polyol (Adiprene™ LFH E1192) with low free HDI content (less than 0.1 wt%). 4 Polytetramethylene ether glycol (2000Mn) 5 BDO = 1,4-butanediol. 6 CHDM = 1,4-cyclohexanedimethanol. 7 Comparative example. 8 Pebax™ 4033—A commercially available polyether block amide sold by Arkema. 9 Aliphatic TPU 10 H12MDI = dicyclohexylmethane-4,4'-diisocyanate. 11 Polytetramethylene ether glycol (1000Mn) 12 Aromatic TPU 13 MDI = 4,4'-methylenebis-(phenylisocyanate).

[0125] Examples 17 to 20 Each of the polymer samples prepared in Examples 13-16 was evaluated to verify the following properties (Shore D hardness, dry flexural modulus, wet flexural modulus, rebound resilience, elongation at break, tensile strength, rebound resilience, and percent softening) utilizing the test protocols described in Examples 7-12. The results are presented in Table 4. [Table 4] 1 Comparative example.

[0126] The results show that the TPU compositions of the disclosed technology offer superior non-softening properties compared to the commercially available benchmark Pebax™ polyether block amide polymer and conventional aliphatic and aromatic TPU compositions, while all other measured properties were comparable. The percent softening and Shore D values ​​for these examples are plotted in Figure 1.

[0127] Examples 21 to 24 A series of thermoplastic polymers were prepared from the components listed in Table 5. [Table 5] 1 First chain extender. 2 Second chain extender. 3 Isocyanate-terminated low free prepolymer: reaction product of hexamethylene diisocyanate (HDI) and polyether polyol (Adiprene™ LFH E1192) with low free HDI content (less than 0.1 wt%). 4 Polytetramethylene ether glycol (2000Mn) 5 BDO = 1,4-butanediol. 6 CHDM = 1,4-cyclohexanedimethanol. 7 Comparative example. 8 Pebax™ 2533—A commercially available polyether block amide sold by Arkema. 9 Aliphatic TPU 10 H12MDI = dicyclohexylmethane-4,4'-diisocyanate. 11Polytetramethylene ether glycol (1000Mn) 12 Aromatic TPU 13 MDI = 4,4'-methylenebis-(phenylisocyanate).

[0128] Examples 25 to 28 Each of the polymer samples prepared in Examples 21-24 was evaluated to verify the following properties (Shore D hardness, dry flexural modulus, wet flexural modulus, rebound resilience, elongation at break, tensile strength, rebound resilience, and percent softening) utilizing the test protocols described in Examples 7-12. The results are presented in Table 6. [Table 6] 1 Comparative example.

[0129] The results show that the TPU of the disclosed technology (Example 25) offers at least equivalent, and in some cases, superior, combinations of properties compared to the commercially available benchmark Pebax™ comparative example and conventional aliphatic and aromatic TPU comparative examples, with all samples having similar hardness. It should be noted that while the TPU of Example 25 has superior softening percentage, tensile strength, and rebound recovery properties compared to the commercially available benchmark of Example 26, the comparative TPUs (Examples 27 and 28) lose one or more of the other physical properties. For example, even though the softening percentages of the TPUs of Examples 27 and 28 are comparable to those of the disclosed technology, the tensile and rebound properties of these comparative TPUs are significantly lower, which adversely affects medical device performance. The softening percentages and Shore D values ​​of these examples are plotted in Figure 1.

[0130] Examples 29 to 32 A series of thermoplastic polymers were prepared from the components listed in Table 7. [Table 7] 1 First chain extender. 2Second chain extender. 3 Isocyanate-terminated low free prepolymer: reaction product of hexamethylene diisocyanate (HDI) and polyether polyol (Adiprene™ LFH E1192) with low free HDI content (less than 0.1 wt%). 4 Polytetramethylene ether glycol (2000Mn) 5 BDO = 1,4-butanediol. 6 CHDM = 1,4-cyclohexanedimethanol.

[0131] Examples 33 to 36 Each of the polymer samples prepared in Examples 29-32 was evaluated to verify the following properties (Shore D hardness, dry flexural modulus, wet flexural modulus, rebound resilience, elongation at break, tensile strength, rebound resilience, and percent softening) utilizing the test protocols described in Examples 7-12. The results are presented in Table 8. [Table 8]

[0132] The polymers of Examples 33-36 exhibited softening rates significantly below 20% while maintaining good tensile strength, dry flexural modulus, dry flexural modulus, elongation at break, and rebound resilience properties. The percent softening and Shore D values ​​for these examples are plotted in Figure 1.

[0133] The Shore D durometer value vs. % softening profile for the example polymers listed in Tables 2, 4, and 6 shows a direct correlation between hardness and non-softening characteristics. As hardness (Shore D durometer value) increases, the degree of softening of the polymer increases. In contrast, the hardness and non-softening characteristics of the TPUs of the disclosed technology are decoupled, i.e., the degree of softening is independent of the hardness of the TPU. The relationship between Shore D durometer hardness value and % softening is shown in Figure 2.

[0134] Example 37 Thermoplastic polymers were prepared from the components listed in Table 9. [Table 9] 1 First chain extender. 2 Second chain extender. 3 Isocyanate-terminated low free prepolymer: reaction product of hexamethylene diisocyanate (HDI) and polyether polyol (Adiprene™ LFH E1192) with low free HDI content (less than 0.1 wt%). 4 BDO = 1,4-butanediol. 5 BEPD = 2-butyl-2-ethyl-1,3-propanediol

[0135] The polymer of Example 37 was tested to verify the following properties (Shore D hardness, dry flexural modulus, wet flexural modulus, rebound resilience, softening, tensile at break, and elongation at break) using the test protocols described above. The results are presented in Table 10. [Table 10] 1 Wet flexural modulus measured at 40°C.

[0136] The results demonstrate that Example 37 exhibits low softening values.

Claims

1. A thermoplastic polyurethane prepared from a reaction mixture comprising: (a) at least one isocyanate-terminated low free polyurethane prepolymer composition prepared from the reaction of at least one polyisocyanate component (i) and at least one polyol component (ii), wherein the low free polyurethane prepolymer composition comprises from greater than 0 wt% to about 1 wt% or less, or from about 0.05 wt% or less to about 0.75 wt% or less, or from about 0.1 wt% or less to about 0.5 wt% or less, of residual polyisocyanate components, based on the total weight of the low free polyurethane prepolymer, and the amount of the low free polyurethane prepolymer ranges from about 1 to about 80 wt%, or from about 15 to about 50 wt%, based on the total weight of the thermoplastic polyurethane; (b) at least one linear, aliphatic polyisocyanate, wherein the weight ratio of the at least one aliphatic polyisocyanate to the low free polyurethane prepolymer ranges from about 10:1 to about 1:10, or from about 1:1 to about 1:2; (c) at least one polyol component in the range of from 0% by weight, or from about 5% by weight to about 80% by weight of the total weight of the thermoplastic polyurethane; (d) a chain extender component comprising: (iii) a first chain extender selected from at least one linear unsubstituted alkanediol containing from about 2 to about 20 carbon atoms; and (iv) a second chain extender selected from at least one cycloaliphatic diol, or at least one aliphatic branched short chain diol, or at least one dianhydrohexitol diol, wherein the weight ratio of the first chain extender to the second chain extender ranges from about 1:19 to about 19:1, or from about 1:1 to about 10:1, or from about 2:1 to about 5:

1.

2. 10. The thermoplastic polyurethane of claim 1, wherein the at least one isocyanate-terminated low free polyurethane prepolymer has an isocyanate content of from about 0.2 to about 15 wt%, or from about 0.5 to about 8 wt%, or from about 5 to about 7 wt%, based on the total weight of the at least one isocyanate-terminated low free polyurethane prepolymer.

3. 3. The thermoplastic polyurethane of claim 1, wherein the at least one isocyanate-terminated low free polyurethane prepolymer comprises less than about 75 wt.%, or less than about 70 wt.%, or less than about 65 wt.%, of a 2:1 stoichiometric adduct of the at least one polyisocyanate (i) and the at least one polyol component (ii), based on the total weight of the low free polyurethane prepolymer.

4. The at least one isocyanate-terminated low free polyurethane prepolymer (a) is selected from the group consisting of 4,4'-methylenebis-(phenylisocyanate) (MDI), m-xylylene diisocyanate (XDI), phenylene-1,4-diisocyanate (PPDI), 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TODI), diphenylmethane-3,3'-dimethoxy-4,4'-diisocyanate, toluene diisocyanate (TDI), and naphthalene-1 4. The thermoplastic polyurethane of claim 1, which is prepared from at least one polyisocyanate component (i) selected from the group consisting of 1,5-diisocyanate, isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (H12MDI), 1,4-cyclohexyl diisocyanate (CHDI), 1,6-hexamethylene diisocyanate (HDI), decane-1,10-diisocyanate, and mixtures thereof.

5. 5. The thermoplastic polyurethane of any one of claims 1 to 4, wherein the at least one isocyanate-terminated low free polyurethane prepolymer (a) is prepared from at least one polyol component (ii) selected from polyether polyols, polyester polyols, polycarbonate polyols, polysiloxane polyols, alkoxylated polysiloxane polyols, polybutadiene polyols, and combinations thereof.

6. 6. The thermoplastic polyurethane of any one of claims 1 to 5, wherein the at least one isocyanate-terminated low free polyurethane prepolymer (a) is prepared from a polyol (ii) selected from at least one polyether polyol selected from poly(ethylene oxide), polyethylene glycol, poly(propylene oxide), polypropylene glycol, and polytetramethylene ether glycol.

7. 7. The thermoplastic polyurethane of any one of claims 1 to 6, wherein the at least one isocyanate-terminated low free polyurethane prepolymer (a) is prepared by the reaction of 1,6-hexamethylene diisocyanate with polytetramethylene ether glycol.

8. The thermoplastic polyurethane of any one of claims 1 to 7, wherein the at least one isocyanate-terminated low free polyurethane prepolymer (a) is terminated with an isocyanatohexyl group.

9. 7. The thermoplastic polyurethane of claim 6, wherein the at least one isocyanate-terminated low free polyurethane prepolymer (a) contains from greater than about 0 wt. % to about 0.5 wt. % or less, or from about 0.1 wt. % or less, or from about 0.05 wt. % or less residual 1,6-hexamethylene diisocyanate.

10. 10. The thermoplastic polyurethane of any one of claims 1 to 9, wherein the at least one isocyanate-terminated low free polyurethane prepolymer (a) comprises less than about 80% by weight of a 2:1 stoichiometric adduct of the at least one polyisocyanate component (i) and the at least one polyol component (ii).

11. The thermoplastic polyurethane of any one of claims 1 to 10, wherein the at least one linear aliphatic polyisocyanate component (b) is 1,6-hexamethylene diisocyanate.

12. 12. The thermoplastic polyurethane of any one of claims 1 to 11, wherein the at least one polyol component (c) is selected from polyether polyols, polyester polyols, polycarbonate polyols, polysiloxane polyols, and polybutadiene polyols.

13. 13. The thermoplastic polyurethane of any one of claims 1 to 12, wherein the at least one polyol component (c) is a polyether polyol selected from poly(ethylene oxide), polyethylene glycol, poly(propylene oxide), polypropylene glycol, and polytetramethylene ether glycol.

14. The thermoplastic polyurethane of any one of claims 1 to 13, wherein the polyether polyol component (c) has a number average molecular weight in the range of about 300 to about 3,000.

15. The thermoplastic polyurethane of any one of claims 1 to 14, wherein the polyether polyol component (c) is polytetramethylene ether glycol.

16. 16. The thermoplastic polyurethane of any one of claims 1 to 15, wherein the first linear unsubstituted alkanediol chain extender (d)(iii) is selected from ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol (BDO), 1,5-pentanediol, 1,6-hexanediol (HDO), 1,7-heptanediol, 1,9-nonanediol, 1,11-undecanediol, and 1,12-dodecanediol.

17. The second chain extender component (d)(iv) is selected from the group consisting of 2,2'-(cyclohexane-1,1-diyl)-diethanol, 4,4'-bicyclohexanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, cyclopentanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,3-cyclododecanediol, 1,4-cyclododecanediol, 1,5-cyclododecanediol, 1,6-cyclododecanediol, 4,4'-isopropyl 17. The thermoplastic polyurethane of any one of claims 1 to 16, wherein the alicyclic diol is selected from the group consisting of lidenedicyclohexanol, 1-(3-hydroxypropyl)cyclohexanol, 2-(3-hydroxypropyl)cyclohexanol, 1,4-cyclohexanediethanol, 1,4-cyclohexanediethanol, 1,2-bis(hydroxymethyl)cyclohexane, 1,2-bis(hydroxyethyl)cyclohexane, 4,4'-isopropylidenebiscyclohexanol, bis(4-hydroxycyclohexyl)methane, and mixtures thereof.

18. The second chain extender component (d)(iv) is selected from the group consisting of neopentyl glycol, tripropylene glycol, 3,3-dimethoxy-1,5-pentanediol, 2-methyl-butanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, dibutyl 1,3-propanediol, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-ethyl- 18. The thermoplastic polyurethane of any one of claims 1 to 17, wherein the aliphatic branched short-chain diol is selected from 1-methyl-1,5-pentanediol, 3-tert-butyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,2-diethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,2-dibutyl-1,3-propanediol, 2,2-methyl-2,3-pentanediol, 3,3-dimethyl-1,2-butanediol, 3-ethyl-1,3-pentanediol, 2-butyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, and mixtures thereof.

19. 19. The thermoplastic polyurethane of any one of claims 1 to 18, wherein the second chain extender component (d)(iv) is a dianhydrohexitol diol selected from isosorbide, isoidide, isomannide, and mixtures thereof.

20. 18. The thermoplastic polyurethane of any one of claims 1 to 17, wherein the first chain extender component is 1,4-butanediol and the second chain extender component is 1,4-cyclohexanedimethanol.

21. 19. The thermoplastic polyurethane of any one of claims 1 to 16 or claim 18, wherein the first chain extender component is 1,4-butanediol and the second chain extender component is 2-methyl-1,3-propanediol, or the first chain extender component is 1,4-butanediol and the second chain extender component is 2-butyl-2-ethyl-1,3-propanediol.

22. 22. The thermoplastic polyurethane of any one of claims 1 to 21, wherein the ratio of polyol components to total chain extender components (first and second) ranges from about 0 to about 20:

1.

23. 23. The thermoplastic polyurethane of any one of claims 1 to 22, wherein the chain extender component comprises from 2% to 35% by weight of the total weight of the polyurethane.

24. of the following characteristics: a) a Shore D hardness of about 20 to about 75 as measured by ASTM D2240; b) a dry flexural modulus of about 4,000 to about 90,000 psi as measured by ASTM D790; c) a wet flexural modulus of about 3,000 to about 50,000 psi as measured by ASTM D790; d) an elongation at break of about 300 to about 750 percent as measured by ASTM D412; e) a tensile strength of about 5,000 to about 10,000 psi as measured by ASTM D412; f) a rebound recovery of from about 40 to about 65 percent as measured by ASTM D2632.

25. The thermoplastic polyurethane of any one of claims 1 to 24, having a % softening of 20 or less.

26. 26. A polymer composition comprising the thermoplastic polyurethane of any one of claims 1 to 25 and one or more additional additives selected from pigments, UV stabilizers, UV absorbers, antioxidants, lubricants, heat stabilizers, hydrolysis stabilizers, crosslinking activators, flame retardants, layered silicates, fillers, colorants, toughening agents, adhesion promoters, impact modifiers, radiopaque agents, antimicrobial agents, and mixtures thereof.

27. An article comprising the thermoplastic polyurethane of any one of claims 1 to 25.

28. 28. The article of claim 27, wherein the article comprises a pacemaker head, an angiography catheter, an angioplasty catheter, an epidural catheter, a thermodilution catheter, a urological catheter, a catheter connector, medical tubing, a cartilage replacement, or a joint replacement.

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