Composition of, system for, and method of making cast polyurethane elastomer, system and method of making and articles thereof

Abstract

A polyurethane elastomer comprising the reaction product of an aliphatic polyisocyanate comprising a cyclohexane and having 70% trans structure, a polyol, and a chain extender which comprises at least 50 mole percent of a dianiline is useful in making articles such as non-pneumatic rollers. A kit for making such polyurethane elastomer can comprise a first part comprising a pre-polymer which is a reaction product of the polyisocyanate and the polyol and a second part comprising the chain extender.

Description

86170-WO-PCT (DC200015PCT)COMPOSITION OF, SYSTEM FOR, AND METHOD OF MAKING CAST POLYURETHANE ELASTOMER, SYSTEM AND METHOD OF MAKING AND ARTICLES THEREOFFIELD OF THE INVENTION

[0001] This invention relates to polyurethane elastomers, particularly cast polyurethane elastomers, and systems useful in preparing such polyurethane elastomers. BACKGROUND OF THE INVENTION

[0002] Cast polyurethane elastomers can provide certain desirable properties. For example, they can achieve hardnesses on a wider range than most other elastomer, while exhibiting outstanding physical properties such as: abrasion, tear resistance, resilience, load bearing, durability, together with high degree of customization flexibility. These characteristics make them popular options for a wide range of applications. Particularly, they have been used in dynamic applications, such as non-pneumatic wheels and rollers, where a low heat buildup and good fatigue resistance are desired.

[0003] Typically, to form articles made with cast polyurethane one reacts a prepolymer (which is the reaction product of a diisocyanate and polyol) with a chain extender to form the cast polyurethane elastomer. This reaction occurs in situ as it is a thermosetting polymer and cannot be readily melted and reformed into other shapes after the polyurethane elastomer has formed.

[0004] Generally, the cast polyurethane elastomers in the wheels and rollers market is dominated by polyurethane elastomers based on use of 1,5 -naphthalene diisocyanate (NDI). Unfortunately, pre-polymers based on NDI have poor stability leading to a short shelf-life. As a result, manufacturers of products of cast polyurethanes based on NDI generally have to themselves produce the prepolymer for use within a few hours of production of the prepolymers. In addition, these prepolymers have a high melting point such that temperatures in excess of 100 °C are needed for processing the prepolymer.

[0005] Alternative cast polyurethane elastomer articles based on other common diisocyanates, such as methylene diphenylene diisocyanate (MDI) and / or toluene diisocyanate (TDI), may be easier to manufacture and to process, but the resulting polyurethane elastomers may not meet demanding dynamic tests due to high internal heat build-up speed (high hysteresis), and / or lower thermal resistance.

[0006] It would be desirable to have a polyurethane elastomer product that provides good dynamic performance (e.g., having the thermal properties needed to withstand the86170-WO-PCT (DC200015PCT) dynamic tests needed for non-pneumatic wheels or rollers) while having better stability and processability than systems based on NDI.SUMMARY OF THE INVENTION

[0007] Disclosed herein is a polyurethane elastomer comprising the reaction product of an aliphatic polyisocyanate comprising a cyclohexane, a polyol, and a chain extender which comprises at least 50 mole percent of a dianiline. The aliphatic polyisocyanate can be l,4-bis(isocyanatomethyl) cyclohexane wherein at least 70% of the molecules have a trans structure. The polyol can be an aliphatic polyol having an average functionality of 1 .7 to 2.5, preferably 1.8 to 2.3, hydroxyl groups per molecule and an OH number of from 20 to 60. The chain extender can comprise at least 50% of ,4'-Methylene-bis (3-chloro-2,6- diethylaniline).

[0008] In another aspect the polyurethane elastomer comprises the reaction product of a diisocyanate having formula O=C=N-L-cyclohexyl-L-N=C=O, where L is a direct bond, or hydrocarbon linking group of 1, 2, or 3 carbon atoms, preferably 1 carbon atom, O=C=N-L- groups are in 1 and 4 positions on the cyclohexyl structure and wherein the structure is at least 70%, preferably at least 80% trans, an aliphatic polyol having an average functionality of 1 .7 to 2.5, preferably 1 .8 to 2.3, hydroxyl groups per molecule and an OH number of from 20 to 60, and a chain extender which comprises at least 50 mole percent of a dianiline having the structure:where L is a direct bond or a hydrocarbon linking group of 1 or 2, preferably 1 carbon atom, one of Ri, R2, R3, R4, and R5 are H, an alkyl group of 1, 2, or 3 carbon atoms, a halogen, or an amine, provided one of Ri, R2, R3, R4, and R5 on each phenyl ring, preferably R3, is an amine ( preferably an -NH2) group, most preferably L is methylene, RI is in each instance a halogen, preferably chlorine, R2 and R4 are alkyl groups or 1, 2, or 3, preferably 2 carbon atoms, and Rs is H.86170-WO-PCT (DC200015PCT)

[0009] Also, disclosed is an article comprising such elastomers.

[0010] Also disclosed is a method of making such an elastomer comprising providing a prepolymer which is the reaction product of the diisocyanate and the aliphatic polyol, and reacting the prepolymer with the chain extender.

[0011] Also disclosed is a system (or kit) for making such an elastomer comprising a first part (e.g., in a first container or compartment) comprising a prepolymer which is the reaction product of the diisocyanate and the aliphatic polyol, and a second part (e.g., in a second separate container or compartment) which comprises the chain extender.DETAILED DESCRIPTION OF THE INVENTION

[0012] It was discovered a system that can provide a polyurethane elastomer with good dynamic performance (e.g. modulus and modulus retention) while being easy to process and having good storage stability. The polyurethane elastomer is the reaction product of (i) a polyisocyanate component which comprises, consists essentially of, or consists of a cyclohexane based diisocyanate, (ii) a polyol component, and (iii) a chain extender comprising a dianiline.|0013 | The isocyanate component used in the system has the formula O=C=N-L- cyclohexyl-L-N=C=O, where L is a direct bond, or hydrocarbon linking group of 1 , 2, or 3 carbon atoms, preferably 1 carbon atom, preferably where the O=C=N-L- groups are in 1 and 4 positions on the cyclohexyl structure. The structure can be at least 70% (i.e. a trans:cis ratio of at least 70:30 which can be determined for example by13C-NMR), preferably at least 80% trans - i.e., the isocyanate groups are opposite planes of the cyclohexane ring. For example, the diisocyanate can have the structure1 ,4-bis(isocyanatomethyl) cyclohexane.

[0014] The polyol is an aliphatic polyol having an average hydroxyl functionality of at least 1.7, at least 1.8, at least 1.9 up to 2.5, up to 2.4, or up to 2.3 hydroxyl groups per molecule, and an OH number of from 20 to 60 mg KOH per gram of sample. TOH number can be the number specified by the vendor or can be determined by ASTM D4274-23. The polyol can have a weight average molecular weight of, for example, from 1000, from 1200,86170-WO-PCT (DC200015PCT) from 1500, or from 1700 up to 10,000, up to 8000, up to 7000, or up to 7500 grams per mole. Molecular weights of oligomeric or polymeric structures as described herein can be determined, for example, by gel permeation chromatography using a polystyrene standard. The polyol can be a polyester polyol, a polyether polyol, a polyester polyether polyol, or a mixture thereof. For example, the polyol can include polymonoethylene glycol-adipate polyol, a polytetramethylene glycol (PTMEG), a polypropylene oxide polyol (PPG polyol), a polycaprolactone polyol, a copolymer of polycaprolactone and PPG polyol, copolymers of caprolactone and PTMEG, poly( 1 ,4-butylene glycol adipate), poly (1 ,6-hexylene glycol adipate) and mixed glycols adipates like, for instance, monoethylene and 1 ,4-butylene glycol adipate, or any combinations of these alternatives.

[0015] The chain extender comprises at least 50% by weight of the chain extender of a dianiline having the structure:where L is a direct bond or a hydrocarbon linking group of 1 or 2, preferably 1 carbon atom, one of Ri, R2, R3, R4, and R5 are H, an alkyl group of 1, 2, or 3 carbon atoms, a halogen, or an amine, provided one of Ri, R2, R3, Rr, and R5 on each phenyl ring, preferably R3, is an amine ( preferably an -NH2) group, most preferably L is methylene, Ri is in each instance a halogen, preferably chlorine, R2 and R4 are alkyl groups or 1, 2, or 3, preferably 2 carbon atoms, and R5 is H. For example, the dianiline can have the structure:86170-WO-PCT (DC200015PCT)4,4'-methylenebis (3-chloro-2,6- diethylaniline) (MCDEA).

[0016] The chain extender comprises at least 50, at least 70, at least 80, at least 90, at least 95, at least 99, or 100wt% of the dianiline based on total weight of the chain extender component. The remainder (if any) of the chain extender can comprise other compounds such as hydroquinone , hydroquinone bis (2-hydroxyethyl) ether, 1,3-Bis (2-hydroxyethyl) resorcinol, ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3 -butanediol, 1 ,4-butanediol (BDO), 1,6-hexanediol, 1 ,4-cyclohexanedimethanol, ethanolamine, methyldiethanolamine, phenyldiethanolamine, aromatic diamines including dimethylthiotoluenediamine or diethyltoluene diamine (commercially available as ETHACURE™ 300 or ETHACURE™ 100 from Ablermarle); and 4,4’-methylene-bis-(2-chloroaniline).

[0017] The polyurethane elastomer is prepared by reacting the isocyanate component, the polyol component and the chain extender. In a first option, all the ingredients are mixed and reacted together simultaneously. In a second option, the isocyanate component is reacted with a portion of the polyol component followed by addition of the remaining portion of the polyol component and the chain extender. In a third option the polyol is pre-reacted with the isocyanate component to form a pre-polymer. The prepolymer can have an amount of unreacted isocyanate in a range of from 3, or from 4 up to 12, up to 11, up to 10, up to 9, or up to 8 weight% based on total weight of the prepolymer. Isocyanate content can be measured, for example, as described in ASTMD5155-19. The pre-polymer can then be reacted with the chain extender and optionally additional isocyanate components such as additional polyols. The additional polyols can be used to adjust the properties of the polyurethane elastomer, such as adjusting hardness. The index (i.e., 100x(moles of isocyanate per mole of isocyanate reactive group) can be from 95, from 96, from 97, from 98, from 99, or from 100 up to 125, up to 120, or up to 115.86170-WO-PCT (DC200015PCT)

[0018] The reaction mixture can also include additional ingredients such as one or more of the following: catalyst, defoamers, anti-oxidants, fillers, colorants, flame retardants, anti-settling agents, water scavengers. The amount of an additional ingredient if present can be from greater than 0 to less than 10, less than 5, less than 3 or less than 1 weight percent based on total weight of the reaction mixture.

[0019] Examples of catalysts include tertiary amines (such as, for example, triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2- (dimethylaminoethoxy)ethanol, diazabicyclo[2.2.2]octane (DABCO), diethylethanolamine, N-cocomoipholine, N,N-diethyl-3-diethylaminopropylamine dimethylbenzylamine, 1,8- Diazabicycloundec-7-ene (DBU),triazabicyclodecene (TBD) and N-methyltriazabyclodecene (MTBD)), organometallic compounds (such as, for example, titanium compounds, iron compounds, bismuth compounds, zinc compounds, or tin compounds, for example tin diacetate, tin dioctanoate, tin dilaurate, or the dialkyltin salts of aliphatic carboxylic acids, for example dibutyltin diacetate or dibutyltin dilaurate), or both.

[0020] The polyurethane elastomer can have a Shore A hardness of from 60, from 65, from 70, from 75, from 80, up to 95 according to ISO 868 or a Shore D hardness of 95 up to 105 also according to ISO 868. The polyurethane elastomer can have a storage modulus G’ at 25°C of from 40, from 50, from 60, or from 70 up to 150 or up to 140 MPa as measured by dynamic mechanical analysis in tension mode (e.g., over 0.25% strain and 6Hz frequency over temperature from -45°C to 240°C). The storage modulus G’ and the loss modulus G” can be determined, for example, as described herein. The polyurethane elastomer can have a modulus retention as determined by dividing the modulus G’ at 150°C by the modulus G’ at 25°C of at least 50, at least 60, or at least 70%. The polyurethane can have a tan delta (which is loss modulus G” divided by storage modulus G’) at 60°C of from 0.025 to 0.04. The tan delta can be less than 0.05 for across a range of temperature of from 40 to 150°C and can be substantially consistent (e.g. no peaks) across that temperature range.

[0021] The polyurethane system as described herein can be used to form cast articles, such as non-pneumatic wheels or rollers, conveyor belts, bumpers, seals and gaskets, printing rollers and blades, or the like.86170-WO-PCT (DC200015PCT)EXAMPLES86170-WO-PCT (DC200015PCT)Prepolymer synthesis:

[0022] All the prepolymers were produced in a 1 -liter reaction vessel equipped with thermometer, mechanical stirrer, and vacuum line. Benzoyl chloride (about 0.01 %) was preblended with the isocyanate and heated up to 80°C. The polyol was added over 30 min while maintaining temperature at max 80°C, typically 75-78 °C, to prevent unwanted sidereactions. After completing the addition of the polyol(s), the prepolymers were digested at 75-78 °C under vacuum for a time ranging from 2 to 4 hours: the prepolymer was then unloaded and stored. After one day it was tested for NCO content according to ASTMD5155-19.Elastomers casting:

[0023] All components are degassed before use and combined according to ratios shown in Table 1 and thoroughly mixed for 20 seconds. The reaction mixture was poured into a pretreated mold with releasing agent. The molds were placed into an oven at 135°C for 1 hour (except for Comparative Ex 1 where the oven treatment was at 110°C for 1 hour). After demolding, a post curing was performed at 110°C for another 23 hours and then the elastomers were transferred into a climate chamber and further annealed at 30°C, 50%RH (relative humidity) for 2 weeks before testing. Index is 100x(the moles of isocyanate groups86170-WO-PCT (DC200015PCT) in the isocyanate component in the reaction mixture divided by the moles of isocyanate reactive groups (e.g. OH groups and / or amine groups from the polyol and chain extender) in the reaction mixture).Testing:

[0024] Cast samples were tested for Shore A hardness using a durometer according to ISO 868. Cast samples also were tested using TA Instrument Q800 with tension fixture under conditions of 0.25% strain and 6Hz frequency over temperature from -45°C to 240°C. to determine storage modulus G' and loss modulus G”. Modulus retention is determined by the value of 100x(G’ at 150°C) / (G’ at 25°C). Tan delta is G’7G’. The results are shown in Table 2. The inventive examples showed significantly improved modulus retention over wide temperature range 25-150°C, versus comparative example 1-3 and 5. Comparative Example 4 was characterized by too fast gel time (less than 6 seconds) which did not allow the casting and subsequent testing of the elastomer.Table 1Table 286170-WO-PCT (DC200015PCT)

[0025] This disclosure further encompasses the following aspects.

[0026] Aspect 1 : A polyurethane elastomer comprising the reaction product of diisocyanates having the structurewherein at least 70%, preferably at least 80%, of the diisocyanates have a trans structure, an aliphatic polyol having an average functionality of 1.7 to 2.5, preferably 1.8 to 2.3, hydroxyl groups per molecule and an OH number of from 20 to 60, and a chain extender comprising at least 50 weight percent based on total weight of the chain extender of a dianiline having thestructure

[0027] Aspect 2: A polyurethane elastomer comprising the reaction product of diisocyanates having formula O=C=N-L-cyclohexyl-L-N=C=O, where L is a direct bond, or hydrocarbon linking group of 1, 2, or 3 carbon atoms, preferably 1 carbon atom, O=C=N-L- groups are in 1 and 4 positions on the cyclohexyl structure and wherein the structure is at least 70%, preferably at least 80% trans, with an aliphatic polyol having an average functionality of 1.7 to 2.5, preferably 1.8 to 2.3, hydroxyl groups per molecule and an OH number of from 20 to 60, and a chain extender which comprises at least 50 mole percent of a dianiline having the structure:86170-WO-PCT (DC200015PCT)where L is a direct bond or a hydrocarbon linking group of 1 or 2, preferably 1 carbon atom, one of Ri, R2, R3, R4, and R5 are H, an alkyl group of 1, 2, or 3 carbon atoms, a halogen, or an amine, provided one of Ri, R2, R3, R4, and R5 on each phenyl ring, preferably R3, is an amine ( preferably an -NH2) group, most preferably L is methylene, Ri is in each instance a halogen, preferably chlorine, R2 and R4 are alkyl groups or 1, 2, or 3, preferably 2 carbon atoms, and R5 is H.

[0028] Aspect 3: The polyurethane elastomer of Aspect 1 or 2 comprising structural units of the diisocyanates in an amount of 10 to 30 weight percent, structural units of the aliphatic polyol in an amount of 60 to 80 weight percent, and structural units of the chain extender in an amount of 10 to 30 weight percent.

[0029] Aspect 4: The polyurethane elastomer of any one of the preceding Aspects wherein the aliphatic polyol is a polyester polyol, a polyether polyol, a polyether-polyester copolymer, or a mixture thereof.

[0030] Aspect 5: The polyurethane elastomer of any one of the preceding Aspects which is the reaction product of a mixture comprising the chain extender and a prepolymer formed from the diisocyanates and the aliphatic polyol.

[0031] Aspect 6: The polyurethane elastomer of Aspect 5 wherein the prepolymer includes unreacted isocyanate groups in an amount of 3 to 12 weight percent based on total weight of the prepolymer.

[0032] Aspect 7 : The polyurethane elastomer of Aspect 5 or 6 wherein the mixture further comprises one or more additional polyols.

[0033] Aspect 8: The polyurethane elastomer of any one of the preceding Aspects wherein the chain extender further comprises one or more additional compounds selected from hydroquinone, hydroquinone bis (2-hydroxyethyl) ether, 1,3-Bis (2-hydroxy ethyl) resorcinol, glycerine, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene86170-WO-PCT (DC200015PCT) glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,3 -butanediol, 1 ,4-butanediol, 1 ,6-hexanediol, 1 ,4-cyclohexanedimethanol, ethanolamine, diethanolamine, methyldiethanolamine, phenyldiethanolamine, trimethylolpropane, dimethylthiotoluenediamine, diethyltoluene diamine; and 4,4’-methylene-bis-(2- chloroaniline).

[0034] Aspect 9: The polyurethane elastomer of any one of the preceding Aspects wherein a ratio of isocyanate groups to hydroxyl groups in the reaction mixture is 98: 100 to 125:100.

[0035] Aspect 10: The polyurethane elastomer of any one of the preceding Aspects having a have a modulus retention (100x(G’ at 150°C divided by G’ at 25°C)) of at least 50, preferably at least 60, or more preferably least 70%.100361 Aspect 11 : The polyurethane elastomer of any one of the preceding Aspects having tan delta of less than 0.05 across a range of temperature of from 40 to 150°C, preferably with no peaks.

[0037] Aspect 12: An article comprising the polyurethane elastomer of any one of Aspects 1-11, preferably wherein the article is a non-pneumatic wheel or roller.

[0038] Aspect 13: A system for making a polyurethane elastomer as in any one of Aspects 1-11, comprising a first part comprising a prepolymer which is the reaction product of the diisocyanates and the aliphatic polyol, and a second part comprising the chain extender.

[0039] Aspect 14: A method of making the polyurethane elastomer of any one of Aspects 1-11, comprising providing a prepolymer which is the reaction product of the diisocyanate and the aliphatic polyol, and reacting the prepolymer with the chain extender.

[0040] Aspect 15: The method of Aspect 14 wherein the prepolymer is stored for at least 12 hours before reacting with the chain extender.

[0041] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other (e.g., ranges of “up to 25 wt.%, or, more specifically, 5 wt.% to 20 wt.%”, is inclusive of the endpoints and all intermediate values of the ranges of “5 wt.% to 25 wt.%,” etc.). Moreover, stated upper and lower limits can be combined to form ranges (e.g. “at least 1 or at least 2 weight percent” and “up to 10 or 5 weight percent” can be combined as the ranges “1 to 10 weight percent”, or “1 to 5 weight percent” or “2 to 10 weight percent” or “2 to 5 weight percent”).

[0042] The disclosure may alternately comprise, consist of, or consist essentially of, any appropriate components herein disclosed. The disclosure may additionally, or86170-WO-PCT (DC200015PCT) alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants or species used in the prior art compositions or that are otherwise not necessary to the achievement of the function and / or objectives of the present disclosure.

[0043] All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference.

[0044] Unless specified to the contrary herein, all test standards are the most recent standard in effect as of the filing date of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standard appears.

Claims

86170-WO-PCT (DC200015PCT)What is claimed is:

1. A polyurethane elastomer comprising the reaction product of diisocyanates having the structurewherein at least 70%, preferably at least 80%, of the diisocyanates have a trans structure, an aliphatic polyol having an average functionality of 1.7 to 2.5, preferably 1.8 to 2.3, hydroxyl groups per molecule and an OH number of from 20 to 60, and a chain extender comprising at least 50 weight percent based on total weight of the chain extender of a dianiline having the structure2. The polyurethane elastomer of claim 1 comprising structural units of the diisocyanate in an amount of 10 to 30 weight percent, structural units of the aliphatic polyol in an amount of 60 to 80 weight percent, and structural units of the chain extender in an amount of 10 to 30 weight percent.

3. The polyurethane elastomer of any one of the preceding claims wherein the aliphatic polyol is a polyester polyol, a polyether polyol, a polyether-polyester copolymer, or a mixture thereof.

4. The polyurethane elastomer of any one of the preceding claims which is the reaction product of a mixture comprising the chain extender and a prepolymer formed from the diisocyanates and the aliphatic polyol.86170-WO-PCT (DC200015PCT)5. The polyurethane elastomer of claim 4 wherein the prepolymer includes unreacted isocyanate groups in an amount of 3 to 12 weight percent based on total weight of the prepolymer.

6. The polyurethane elastomer of claim 4 or 5 wherein the mixture further comprises one or more additional polyols.

7. The polyurethane elastomer of any one of the preceding claims wherein the chain extender further comprises one or more additional compounds selected from hydroquinone, hydroquinone bis (2-hydroxyethyl) ether, 1,3-Bis (2-hydroxyethyl) resorcinol, glycerine, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, 1,3 -propanediol, 1,3 -butanediol, 1 ,4-butanediol, 1,6- hexanediol, 1,4-cyclohexanedimethanol, ethanolamine, diethanolamine, methyldiethanolamine, phenyldiethanolamine, trimethylolpropane, dimethylthiotoluenediamine, diethyltoluene diamine; and 4,4’-methylene-bis-(2- chloroaniline).

8. The polyurethane elastomer of any one of the preceding claims wherein a ratio of isocyanate groups to hydroxyl groups in the reaction mixture is 98: 100 to 125:100.

9. A polyurethane elastomer comprising the reaction product of a diisocyanate having formula O=C=N-L-cyclohexyl-L-N=C=O, where L is a direct bond, or hydrocarbon linking group of 1, 2, or 3 carbon atoms, preferably 1 carbon atom, O=C=N-L- groups are in 1 and 4 positions on the cyclohexyl structure and wherein the structure is at least 70%, preferably at least 80% trans, an aliphatic polyol having an average functionality of 1.7 to 2.5, preferably 1.8 to 2.3, hydroxyl groups per molecule and an OH number of from 20 to 60, and a chain extender which comprises at least 50 mole percent of a dianiline having the structure:86170-WO-PCT (DC200015PCT) where L is a direct bond or a hydrocarbon linking group of 1 or 2, preferably 1 carbon atom, one of Ri, R2, R3, R4, and R5 are H, an alkyl group of 1, 2, or 3 carbon atoms, a halogen, or an amine, provided one of Ri, R2, R3, R4, and Rs on each phenyl ring, preferably R3, is an amine ( preferably an -NH2) group, most preferably L is methylene, Ri is in each instance a halogen, preferably chlorine, R2 and R4 are alkyl groups or 1, 2, or 3, preferably 2 carbon atoms, and Rs is H.

10. The polyurethane elastomer of any one of claims 1-9 having a modulus retention which is 100x(a modulus G’ of the polyurethane elastomer at 150°C divided by a modulus G’ of the polyurethane elastomer at 25°C, of at least 50%.

11. The polyurethane elastomer of any one of claims 1-10 having a tan delta of less than 0.05 for a range of temperatures from 40 to 150°C.

12. An article comprising the polyurethane elastomer of any one of claims 1-11, preferably wherein the article is a non-pneumatic wheel or roller.

13. A system for making a polyurethane elastomer as in anyone of claims 1-11 comprising a first part comprising a prepolymer which is the reaction product of the diisocyanates and the aliphatic polyol, and a second part comprising the chain extender.

14. A method of making the polyurethane elastomer of any one of claims 1-11 comprising providing a prepolymer which is the reaction product of the diisocyanate and the aliphatic polyol, and reacting the prepolymer with the chain extender.

15. The method of claim 14 wherein the prepolymer is stored for at least 12 hours before reacting with the chain extender.

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