Thermoplastic polyurethane having a non-flat geometry and low hysteresis

Abstract

The invention provides an article having a non-flat geometry, wherein the non-flat geometry can be a sphere or hemisphere formed from a thermoplastic polyurethane having a low tan delta a high rebound and wherein the article demonstrates low hysteresis. The article may be useful in applications such as tennis balls.

Description

4845-01- 1 -TITLEThermoplastic Polyurethane Having a Non-Flat Geometry and Low Hysteresis SUMMARY OF THE INVENTION

[0001] The present invention provides an article constructed from thermoplastic polyurethane wherein the article has a non-flat geometry, in particular, a sphere or hemisphere. The article of the present invention comprises a sphere or hemisphere, wherein the sphere or hemisphere is formed from a thermoplastic polyurethane, wherein the thermoplastic polyurethane has a tan delta of less than 0.05, a crystallization temperature of greater than 60°C, and a rebound of greater than 50 inches, and wherein the injection molded sphere or hemisphere demonstrates a hysteresis at 18 lbs load of less than 30% and a forward deformation of 0.21 inches or less.

[0002] The following embodiments of the present subject matter are contemplated:

[0003] 1. An article having a non-flat geometry comprising: a sphere or hemisphere, wherein the sphere or hemisphere is formed from a thermoplastic polyurethane, wherein the thermoplastic polyurethane has a tan delta measured according to ASTM D5026 (Tension Mode, Sample size 20 mm x 6.35 x 0.08 mm at 1 Hz and at 25°C or higher) of less than 0.05, a Tc of greater than 60°C or 60°C to 120°C measured according to ASTM D3418 and a rebound measured according to ASTM D2632 of greater than 50 inches or greater than 60 inches, and wherein the injection molded sphere or hemisphere demonstrates a hysteresis at 18 lbs load of less than 30% and a forward deformation of 0.21 inches or less.

[0004] 2. The article of embodiment 1, wherein the sphere or hemisphere has a load at 1 inch displacement of less than 100 Ibs-force measured according to ASTM D2731.

[0005] 3. The article of embodiment 1 wherein the thermoplastic polyurethane comprises the reaction product of a polyol component, a hydroxyl terminated chain extender component, and a diisocyanate component.

[0006] 4. The article of embodiment 3, wherein a combined weight of the diisocyanate component and the chain extender component make up a hard segment4845-01- 2 - of the thermoplastic polyurethane and wherein the thermoplastic polyurethane comprises 30 wt% or less or 28 wt% or less hard segment.

[0007] 5. The article of embodiment 4, wherein the thermoplastic polyurethane comprises 20 wt% to 30 wt% hard segment or 24 wt% to 28 wt% hard segment.

[0008] 6. The article of any of embodiments 3 to 5, wherein the polyol component comprises or consists of a polyether polyol.

[0009] 7. The article of embodiment 6, wherein the polyol component comprises or consists of polytetramethylene ether glycol.

[0010] 8. The article of any of embodiments 3 to 5, wherein the polyol component comprises or consists of a copolymer of polytetramethylene ether glycol and polycaprolactone polyol.

[0011] 9. The article of any of embodiments 3 to 5, wherein the polyol component comprises or consists of a polyester polyol.

[0012] 10. The article of embodiment 9, wherein the polyol component comprises or consists of a hydroxyl terminated polyester polyol prepared from the reaction of adipic acid with a mixture of 1,4 butanediol and 1,6 hexanediol.

[0013] 11. The article of any of embodiments 3 to 10, wherein the chain extender component comprises or consists of hydroquinone bi s(2 -hydroxy ethyl) ether.

[0014] 12. The article of any of embodiments 3 to 11, wherein the diisocyanate component comprises or consists of methylene diphenyl diisocyanate.

[0015] 13. A ball comprising: a core defining an internal volume, the core being entirely formed from a thermoplastic polyurethane, wherein the thermoplastic polyurethane has a tan delta measured according to ASTM D5026 of less than 0.05, a Tc of greater than 60°C or 60°C to 120°C measured according to ASTM D3418 and a rebound measured according to ASTM D2632 of greater than 50 inches or greater than 60 inches, and wherein the core demonstrates a hysteresis at 18 lbs load of less than 30% and a forward deformation of 0.21 inches or less.

[0016] 14. The ball of embodiment 13, wherein the core is valveless.

[0017] 15. The ball of embodiment 13 or 14, wherein the core has a load at 1 inch displacement of less than 100 Ibs-force.4845-01- 3 -

[0018] 16. The ball of any of embodiments 13 to 15, wherein the thermoplastic polyurethane comprises the reaction product of a polyol component, a hydroxyl terminated chain extender component, and a diisocyanate component.

[0019] 17. The ball of embodiment 16, wherein a combined weight of the diisocyanate component and the chain extender component make up a hard segment of the thermoplastic polyurethane and wherein the thermoplastic polyurethane comprises 30 wt% or less or 28 wt% or less hard segment.

[0020] 18. The ball of embodiment 17, wherein the thermoplastic polyurethane comprises 20 wt% to 30 wt% hard segment or 24 wt% to 28 wt% hard segment.

[0021] 19. The ball of any of embodiments 16 to 18, wherein the polyol component comprises or consists of a polyether polyol.

[0022] 20. The ball of embodiment 19, wherein the polyol component comprises or consists of polytetramethylene ether glycol.

[0023] 21. The ball of any of embodiments 16 to 18, wherein the polyol component comprises or consists of a copolymer of polytetramethylene ether glycol and polycaprolactone polyol.

[0024] 22. The ball of any of embodiments 16 to 18, wherein the polyol component comprises or consists of a polyester polyol.

[0025] 23. The ball of embodiment 22, wherein the polyol component comprises or consists of a hydroxyl terminated polyester polyol prepared from the reaction of adipic acid with a mixture of 1,4 butanediol and 1,6 hexanediol.

[0026] 24. The ball of any of embodiments 16 to 23, wherein the chain extender component comprises or consists of hydroquinone bi s(2-hydroxy ethyl) ether.

[0027] 25. The ball of any of embodiments 16 to 24, wherein the diisocyanate component comprises or consists of methylene diphenyl diisocyanate.BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG. 1 is a sectional view of a non-flat geometry.

[0029] FIG. 2 is a second view of a non-flat geometry.

[0030] FIG. 3 illustrates how 2 hemispheres having non-flat geometry may be used to form a spherical non-flat geometry.4845-01- 4 -DETAILED DESCRIPTION OF THE INVENTION

[0031] The invention herein provides an article having a non-flat geometry comprising: a sphere or hemisphere, wherein the sphere or hemisphere is formed from a thermoplastic polyurethane, wherein the thermoplastic polyurethane has a tan delta of less than 0.05, a crystallization temperature of greater than 60°C, and a rebound of greater than 50 inches or greater than 60 inches, and wherein the injection molded sphere or hemisphere demonstrates a hysteresis at 18 lbs load of less than 30% and a forward deformation of 0.21 inches or less.Thermoplastic Polyurethane

[0032] The non-flat geometry of the present invention is constructed from a thermoplastic polyurethane (TPU) composition. A thermoplastic polyurethane is generally prepared by reacting a diisocyanate with a polyol intermediate, and, optionally, a chain extender component, all of which are well known to those skilled in the art.

[0033] Thermoplastic polyurethanes used in the present invention are made using a polyisocyanate component. In some embodiments, the polyisocyanate component includes one or more diisocyanates. Useful diisocyanates may be selected from aromatic diisocyanates or aliphatic diisoyisocyanates or combinations thereof. Examples of useful diisocyanates include, but are not limited to aromatic diisocyanates such as 4,4'-methylenebis(phenyl isocyanate) (MDI), m-xylene diisocyanate (XDI), phenylene-l,4-diisocyanate, 3,3’-dimethyl-4,4’-biphenylene diisocyanate (TODI), 1,5 -naphthalene diisocyanate (ND I), and toluene diisocyanate (TDI), as well as aliphatic diisocyanates such as isophorone diisocyanate (IPDI), 1,6-hexam ethylene diisocyanate (HDI), 1,4-cyclohexyl diisocyanate (CHDI), decane- 1,10-diisocyanate, lysine diisocyanate (LDI), 1,4-butane diisocyanate (BDI), and dicyclohexylmethane- 4,4 '-diisocyanate (H12MDI). In some embodiments, mixtures of two or more polyisocyanates may be used.

[0034] In some embodiments, the polyisocyanate component comprises or consists of one or more aromatic diisocyanates. In some embodiments, the polyisocyanate component is essentially free of, or even completely free of, aliphatic diisocyanates.4845-01- 5 -

[0035] Thermoplastic polyurethane compositions used in the present invention are also made using a polyol intermediate. Polyol intermediates may include, but are not limited to polyether polyols and polyester polyols or combinations thereof.

[0036] Polyether polyols that may be useful as the polyol component of the TPU of the present invention include polyether polyols derived from a diol or polyol having a total of from 2 to 15 carbon atoms. In some embodiments, the hydroxyl terminated polyether is an alkyl diol or glycol which is reacted with an ether comprising an alkylene oxide having from 2 to 6 carbon atoms, typically ethylene oxide or propylene oxide or mixtures thereof. For example, hydroxyl functional polyether can be produced by first reacting propylene glycol with propylene oxide followed by subsequent reaction with ethylene oxide. Primary hydroxyl groups resulting from ethylene oxide are more reactive than secondary hydroxyl groups and thus are preferred. Useful commercial polyether polyols include poly(ethylene glycol) comprising ethylene oxide reacted with ethylene glycol, polypropylene glycol) comprising propylene oxide reacted with propylene glycol, poly(tetramethylene glycol) comprising water reacted with tetrahydrofuran which can be described as polymerized tetrahydrofuran, and which is commonly referred to as PTMEG. In some embodiments, the polyether polyols may have a number average molecular weight (Mn) of 500 to 5000, for example, 1000 to 3000 or mixtures thereof.

[0037] Polyester polyols may also be useful as the polyol intermediate in the present invention. In general, polyester intermediates are produced by (1) an esterification reaction of one or more glycols with one or more dicarboxylic acids or anhydrides or (2) by transesterification reaction, i.e., the reaction of one or more glycols with esters of dicarboxylic acids. Mole ratios generally in excess of more than one mole of glycol to acid are preferred so as to obtain linear chains having a preponderance of terminal hydroxyl groups. The dicarboxylic acids polyester may include aliphatic, cycloaliphatic, aromatic, or combinations thereof. Dicarboxylic acids may be used alone or in mixtures and generally have a total of from 4 to 15 carbon atoms and include: succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, isophthalic, terephthalic, cyclohexane dicarboxylic, and the like. Anhydrides of the above dicarboxylic acids such as phthalic anhydride, tetrahydrophthalic anhydride, or the like, can also be used. The glycols which are reacted to form a4845-01- 6 - desirable polyester intermediate can be aliphatic, aromatic, or combinations thereof, and have a total of from 2 to 20 or from 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-l,3-propanediol, 1,4- cyclohexanedimethanol, decamethylene glycol, dodecamethylene glycol, and mixtures thereof.

[0038] In one embodiment, the polyol component comprises a polycaprolactone polyester polyol. The polycaprolactone polyester polyols useful for making the TPU compositions described herein include polyester diols derived from caprolactone monomers. The polycaprolactone polyester polyols are terminated by primary hydroxyl groups. Suitable polycaprolactone polyester polyols may be made from s-caprolactone and a bifunctional initiator such as di ethylene glycol, 1,4-butanediol, or any of the other glycols and / or diols known in the art for this purpose. In some embodiments, the polycaprolactone polyester polyols are linear polyester diols derived from caprolactone monomers.

[0039] Useful examples include CAPA™ 2202A, a 2000 number average molecular weight (Mn) linear polyester diol, and CAPA™ 2302 A, a 3000 Mn linear polyester diol, both of which are commercially available. These materials may also be described as polymers of 2-oxepanone and 1,4-butanediol.

[0040] The polycaprolactone polyester polyols may be prepared from 2-oxepanone and a diol, where the diol may be 1,4-butanediol, di ethylene glycol, monoethylene glycol, hexane diol, 2,2-dimethyl-l,3-propanediol, or any combination thereof. In some embodiments, the diol used to prepare the poly caprolactone polyester polyol is linear. In some embodiments, the poly caprolactone polyester polyol is prepared from 1,4- butanediol.

[0041] In some embodiments, the polyol component comprises or consists of polytetramethylene ether glycol. In some embodiments, the polyol component comprises or consists of a copolymer of polytetramethylene ether glycol and polycaprolactone polyol. In some embodiments, the polyol component comprises or consists of a hydroxyl terminated polyester polyol prepared from the reaction of adipic acid with a mixture of 1,4 butanediol and 1,6 hexanediol.

[0042] The TPU used in the construction of the article of the present invention optionally includes a chain extender component. Suitable chain extenders include4845-01- 7 - relatively small polyhydroxy compounds, for example lower aliphatic or short chain glycols having from 2 to 20, or 2 to 12, or 2 to 10 carbon atoms. Suitable examples include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol (BDO), 1,6-hexanediol (HDO), 1,3-butanediol, 1,5-pentanediol, neopentylglycol, 1,4-cyclohexanedimethanol (CHDM), 2,2-bis[4-(2-hydroxyethoxy) phenyl]propane (HEPP), heptanediol, nonanediol, dodecanediol, 3-methyl-l,5-pentanediol, and hydroxyethyl resorcinol (HER), pentaspiro glycol (PSG), hydroquinone bis(2-hydroxyethyl) ether (HQEE), dipropylene glycol (DPG), 2-methyl-l,3-propane diol, 2-butyl-2-ethyl-l,3-propane diol (BEPD), and the like, as well as mixtures thereof. In one embodiment, the chain extender component comprises, consists essentially of, or consists of hydroquinone bis(2-hydroxy ethyl) ether.

[0043] In one embodiment, the article of the present invention is formed from a thermoplastic polyurethane wherein the thermoplastic polyurethane comprises the reaction product of a polyol component wherein the polyol component comprises or consists of polytetramethylene ether glycol, the diisocyanate comprises methylene diphenyl diisocyanate, and the chain extender comprises hydroquinone bis(2- hydroxyethyl) ether. In another embodiment, the article of the present invention is formed from a thermoplastic polyurethane wherein the thermoplastic polyurethane comprises or consists of the reaction product of a polyol component wherein the polyol component comprises or consists of a copolymer of polytetramethylene ether glycol and a polycaprolactone polyol, the diisocyanate comprises methylene diphenyl diisocyanate, and the chain extender comprises hydroquinone bis(2- hydroxy ethyl) ether. The combined weight of the diisocyanate and the chain extender used in the preparation of the thermoplastic polyurethane make up the “hard segment” of the thermoplastic polyurethane. For applications contemplated in the present application, the thermoplastic polyurethane has a hard segment content of 30 wt% or less, for example 28 wt% or less, or further for example, from 20 wt% to 30 wt% or even further for example, from 24 wt% to 28wt%.

[0044] For certain applications of the non-flat geometry, the properties of the TPU material are important to ensure that the article meets certain performance requirements. For example, the TPU used in the present invention has a tan delta4845-01- 8 - measured according to ASTM D5026 (Tension Mode, sample size 20 mm x 6.35 x 0.08 mm at 1 Hz and at 25°C or higher, or 25°C to 50°C) of less than 0.05. For certain applications of the non-flat geometry, the TPU has a crystallization temperature of greater than 60°C. For certain applications of the non-flat geometry, the TPU has a crystallization temperature of 60°C to 120°C as measured by ASTM D3418. In addition, the TPU used in the present invention may also have a rebound measured according to ASTM D2632 of greater than 50 inches or greater than 60 inches, wherein the rebound is measured using a compression molded plaque.

[0045] The non-flat articles of the present invention may be spheres or hemispheres as shown in the attached figures. The spheres or hemispheres may be prepared using methods now known to those skilled in the art of forming thermoplastic materials or hereafter developed and known in the art. Examples of methods include but are not limited to injection molding, roto-molding, spin molding, blowing molding, or 3D printing. FIG. 1 illustrates a hemisphere 1 prepared using the TPU material described herein. FIG. 2 is a second view of a hemisphere 2 having a hollow interior 3. However, it is contemplated that solid hemispheres or spheres may be included in the scope of the invention. FIG. 3 illustrates two hemispheres 4 and 5 being assembled to form a sphere 6. In one embodiment of the present invention, the article is a ball. In another embodiment of the present invention, the article makes up the core of a tennis ball.

[0046] Regardless of the method of preparation of the non-flat geometry, it is an aspect of the present invention that the non-flat geometry demonstrate a hysteresis at 181bs load of less than 30% as measured according to ASTM D2731 (5 cycles, 1 inch displacement length, 20 cm / min). In another aspect, the non-flat geometry exhibits a forward deformation of 0.21 inches or less (measured using the method specified in the 2024 ITF Technical Booklet (ITF Approved Tennis Balls, Classified Surfaces & Recognised Courts A Guide to Products & Test Methods available a ww , itftemii s . com) at pages 14-15 with the modification that the contact load of 15.57 + 0.5 N (3.5 + 0.1 Ibf is not applied - this accounts for the fact that the measurements in this case are made on a sphere without the need to compress a felt layer). In one embodiment, the non-flat geometry also demonstrates a load at 1 inch displacement of less than 100 Ibs-force measured according to ASTM D2731.4845-01- 9 -

[0047] Without intending to limit the scope of the invention, the following examples illustrate preparation and evaluation of examples of non-flat geometries within the scope of the present invention.EXAMPLES

[0048] A series of thermoplastic polyurethane materials was prepared as set forth in Table 1.Table 11Combined weight of chain extender and isocyanate.2ASTM D3418 3 ASTM D5026, Tension Mode, Sample size 20 mm x 6.35 x 0.08 mm at 1 Hz and at 25°C or higher4ASTM D263251,4-butanediol6Ethylene glycol7Hydroquinone bis(2-hydroxylethyl) ether 8 Dipropylene glycol9Trimethylol propane10Undetected4845-01

[0049] The TPU compositions from Table 1 were injected molded into hemispheres which were assembled into spheres (as shown in FIG. 3) and evaluated for suitability for use in certain articles. The results are summarized in Table 2.Table 21ASTM D3574 (changes from standard are test speed of 20 in / min, 5 cycles with 1 inch displacement length, during this test hysteresis is reported at 18 lbs. load).2ASTM D3574 (changes from standard are test speed of 20 in / min, 5 cycles with 1 inch displacement length, during this test load required to displace one inch is reported)3Measured using the method specified in the 2024 ITF Technical Booklet (ITF Approved Tennis Balls, Classified Surfaces & Recognised Courts A Guide to Products & Test Methods available a wwwJtflfiSfflS^com) with the modification that the contact load of 15.57 + 0.5 N (3.5 + 0.1 Ibf is not applied at pages 14-15.

[0050] It is known that some of the materials described above may interact in the final formulation, so that the components of the final formulation may be different from those that are initially added. The products formed thereby, including the products formed upon employing lubricating grease compositions of the present invention in its intended use, may not be susceptible of easy description. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses lubricating grease compositions prepared by admixing the components described above.4845-01- 11 -

[0051] Each of the documents referred to above is incorporated herein by reference. Except in the Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word "about." Unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade. However, the amount of each chemical component is presented exclusive of any solvent or diluent oil, which may be customarily present in the commercial material, unless otherwise indicated. It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined. Similarly, the ranges and amounts for each element of the invention may be used together with ranges or amounts for any of the other elements.

[0052] While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.

Claims

4845-01- 12 -What is claimed is:

1. An article having a non-flat geometry comprising: a sphere or hemisphere, wherein the sphere or hemisphere is formed from a thermoplastic polyurethane, wherein the thermoplastic polyurethane has a tan delta measured according to ASTM D5026 (Tension Mode, Sample size 20 mm x 6.35 x 0.08 mm at 1 Hz and at 25°C or higher) of less than 0.05, a Tc of greater than 60°C measured according to ASTM D3418 and a rebound measured according to ASTM D2632 of greater than 50 inches, and wherein the injection molded sphere or hemisphere demonstrates a hysteresis at 18 lbs load of less than 30% and a forward deformation of 0.21 inches or less.

2. The article of claim 1, wherein the sphere or hemisphere has a load at 1 inch displacement of less than 100 Ibs-force measured according to ASTM D2731.

3. The article of claim 1 wherein the thermoplastic polyurethane comprises the reaction product of a polyol component, a hydroxyl terminated chain extender component, and a diisocyanate component.

4. The article of claim 3, wherein a combined weight of the diisocyanate component and the chain extender component make up a hard segment of the thermoplastic polyurethane and wherein the thermoplastic polyurethane comprises 30 wt% or less hard segment.

5. The article of claim 4, wherein the thermoplastic polyurethane comprises 20 wt% to 30 wt% hard segment.

6. The article of any of claims 3 to 5, wherein the polyol component comprises a polyether polyol.4845-01- 13 -7. The article of claim 6, wherein the polyol component comprises polytetram ethylene ether glycol.

8. The article of any of claims 3 to 5, wherein the polyol component comprises a copolymer of polytetramethylene ether glycol and polycaprolactone polyol.

9. The article of any of claims 3 to 5, wherein the polyol component comprises a polyester polyol.

10. The article of claim 9, wherein the polyol component comprises a hydroxyl terminated polyester polyol prepared from the reaction of adipic acid with a mixture of 1,4 butanediol and 1,6 hexanediol.

11. The article of any of claims 3 to 10, wherein the chain extender component comprises hydroquinone bis(2 -hydroxyethyl) ether.

12. The article of any of claims 3 to 11, wherein the diisocyanate component comprises methylene diphenyl diisocyanate.

13. A ball comprising: a core defining an internal volume, the core being entirely formed from a thermoplastic polyurethane, wherein the thermoplastic polyurethane has a tan delta measured according to ASTM D5026 of less than 0.05, a Tc of greater than 60°C measured according to ASTM D3418 and a rebound measured according to ASTM D2632 of greater than 50 inches, and wherein the core demonstrates a hysteresis at 18 lbs load of less than 30% and a forward deformation of 0.21 inches or less.

14. The ball of claim 13, wherein the core is valveless.

15. The ball of claim 13 or 14, wherein the core has a load at 1 inch displacement of less than 100 Ibs-force.4845-01- 14 -16. The ball of any of claims 13 to 15, wherein the thermoplastic polyurethane comprises the reaction product of a polyol component, a hydroxyl terminated chain extender component, and a diisocyanate component.

17. The ball of claim 16, wherein a combined weight of the diisocyanate component and the chain extender component make up a hard segment of the thermoplastic polyurethane and wherein the thermoplastic polyurethane comprises 30 wt% or less hard segment.

18. The ball of claim 17, wherein the thermoplastic polyurethane comprises 20 wt% to 30 wt% hard segment.

19. The ball of any of claims 16 to 18, wherein the polyol component comprises a poly ether polyol.

20. The ball of claim 19, wherein the polyol component comprises polytetram ethylene ether glycol.

21. The ball of any of claims 16 to 18, wherein the polyol component comprises a copolymer of polytetramethylene ether glycol and polycaprolactone polyol.

22. The ball of any of claims 16 to 18, wherein the polyol component comprises a polyester polyol.

23. The ball of claim 22, wherein the polyol component comprises a hydroxyl terminated polyester polyol prepared from the reaction of adipic acid with a mixture of 1,4 butanediol and 1,6 hexanediol.

24. The ball of any of claims 16 to 23, wherein the chain extender component comprises hydroquinone bis(2-hydroxyethyl) ether.4845-01- 15 -25. The ball of any of claims 16 to 24, wherein the diisocyanate component comprises methylene diphenyl diisocyanate.

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