Thermoplastic polyurethane composition

Abstract

To provide a thermoplastic polyurethane composition.SOLUTION: The present invention relates to a thermoplastic polyurethane material that has a high flexural modulus, low density, and can withstand repeated periodic deformation. The thermoplastic polyurethane composition contains a polyol component comprising a blend of polyether polyols, such as poly(tetramethylene ether glycol), and polybutadiene diols, and a reaction product of a diisocyanate component and a chain extender component. The thermoplastic polyurethane composition is generally formed from a reaction product of the polyol component, the diisocyanate component, and optionally the chain extender component. In the thermoplastic polyurethane composition of the present invention, the polyol component is a blend of polyols, which includes polyether polyols and polybutadiene polyols.SELECTED DRAWING: None

Description

Background Art

[0001] The usefulness of thermoplastic polyurethane materials in various applications has been evaluated in many new industries. However, it is often difficult to discover a single thermoplastic polyurethane composition having a combination of properties suitable for a particular application. For example, in many applications, high modulus of elasticity and hardness are required, but the ability to withstand cyclic deformation and various temperature ranges is also required. In many cases, polyamide-co-polyether is used for these applications because it has a high flexural modulus, low density, and good low-temperature fatigue resistance. However, thermoplastic polyurethane compositions having a high flexural modulus lack low-temperature cyclic fatigue behavior and are unnecessarily heavy. One reason for this is that in order to achieve a high flexural modulus, the hard segment content of the thermoplastic polyurethane increases, and the density and glass transition temperature also increase. When the density and glass transition temperature increase, the desired performance deteriorates when subjected to cyclic deformation. Therefore, an object of the present invention is to provide a thermoplastic polyurethane composition having an unexpected combination of properties including a high modulus of elasticity, low density, and the ability to maintain cyclic deformation.

Summary of the Invention

Means for Solving the Problems

[0002] The present invention is a thermoplastic polyurethane composition containing a reaction product of a polyol component and a diisocyanate component, and the polyol component includes a mixture of a polyether polyol and a polybutadiene polyol. Examples of the polyether polyol include poly(tetramethylene ether glycol), polypropylene glycol, polyethylene glycol, and polyoxymethylene. The polybutadiene polyol may include an unsaturated polybutadiene polyol or diol or polybutadiene diol. In one embodiment, the polyol component includes or consists of a mixture of poly(tetramethylene ether glycol) and a polybutadiene polyol. In another embodiment, the polyol component includes or consists of a mixture of poly(tetramethylene ether glycol) and an unsaturated polybutadiene polyol. In yet another embodiment, the polyol component includes a polyether component that is a blend of poly(tetramethylene ether glycol) and poly(propylene glycol) end-capped with ethylene oxide and a polybutadiene polyol. The thermoplastic polyurethane composition may optionally include a chain extender component. The present invention also includes an article made from the thermoplastic polyurethane composition of the present invention.

Mode for Carrying Out the Invention

[0003] The thermoplastic polyurethane composition is generally formed from a reaction product of a polyol component, a diisocyanate component, and optionally a chain extender component. In the thermoplastic polyurethane composition of the present invention, the polyol component is a blend of polyols, and the blend contains a polyether polyol and a polybutadiene polyol.

[0004] Polyol Component The polyol component used in the thermoplastic polyurethane composition of the present invention is a blend of polyols, and the blend contains a polyether polyol and a polybutadiene polyol.

[0005] Polyether polyols are typically derived from diols or polyols having a total of 2 to 15 carbon atoms, and in some embodiments, alkylene oxides having 2 to 6 carbon atoms, typically ethylene oxide or propylene oxide or mixtures thereof react with ethers derived from alkyldiols or glycols. For example, hydroxyl-functional polyethers can be produced by first reacting propylene glycol with propylene oxide and subsequently reacting with ethylene oxide. Primary hydroxyl groups obtained from ethylene oxide are preferred because they are more reactive than secondary hydroxyl groups. Useful commercially available polyether polyols include poly(ethylene glycol) containing ethylene oxide reacted with ethylene glycol, poly(propylene glycol) containing propylene oxide reacted with propylene glycol, and poly(tetramethylene ether glycol) containing water reacted with tetrahydrofuran, which is usually referred to as PTMEG. Suitable polyether polyols also include polyamide adducts of alkylene oxides, for example, ethylenediamine adducts containing reaction products of ethylenediamine and propylene oxide, diethylenetriamine adducts containing reaction products of diethylenetriamine and propylene oxide, and similar polyamide-type polyether polyols. Copolymers can also be utilized in the described compositions. Typical copolymers include reaction products of THF and ethylene oxide or THF and propylene oxide. These are available from BASF as the block copolymer PolyTHF® B and the random copolymer PolyTHF® R.

[0006] In one embodiment, the polyether polyol used in the present invention has a number average molecular weight (Mn) determined by assay of terminal functional groups of about 700 to about 10,000, such as about 1,000 to about 5,000, or further about 1,000 to about 3,000, or further 1000 to about 2500, or further about 2000 to about 2500. In one embodiment, the number average molecular weight of the polyether polyol used in the present invention is less than 3000.

[0007] In one embodiment, the polyether polyol used in the polyol component of the present invention comprises or consists of poly(tetramethylene ether glycol). In another embodiment, the polyether polyol used in the polyol component is a blend of polyether polyols. For example, the blend of polyether polyols comprises or consists of poly(tetramethylene ether glycol) and poly(propylene glycol) end-capped with ethylene oxide.

[0008] The polyol component of the present invention also includes polybutadiene polyol. In one embodiment, the polybutadiene polyol is unsaturated. In one embodiment, the polybutadiene polyol comprises or consists of polybutadiene diol, which also refers to hydroxyl-terminated polybutadiene as used herein. The molecular weight of the polybutadiene polyol used to form the thermoplastic polyurethane of the present invention depends on the desired characteristics of the article to be produced. Suitable polybutadiene polyols for forming the thermoplastic polyurethane composition according to the present invention can have a molecular weight of about 100 to about 10,000, such as about 300 to about 5,000, further such as about 1,000 to about 3,000, for example 2,000. In some embodiments, the polybutadiene polyol has 2.0 to 3.0, such as 2.0 to 2.6 OH functional groups.

[0009] In one embodiment, the polybutadiene polyol is unsaturated and the polybutadiene polyol contains double bonds along the butadiene chain.

[0010] Commercially available polybutadiene polyols useful in the present invention include KRASOL™ LBH P-2000, KRASOL™ LBH 2000, and KRASOL™ HLBH P-2000 available from Cray Valley, and NISSO™ PB G 2000, NISSO™ PB-G1400, NISSO™ PB-GI1000, and NISSO PB-GI2000 available from Nippon Soda Co. are included.

[0011] Polyisocyanate component The thermoplastic polyurethane composition described herein is prepared using a polyisocyanate component. The polyisocyanate and / or polyisocyanate component may include one or more polyisocyanates. In some embodiments, the polyisocyanate component includes one or more diisocyanates.

[0012] Suitable polyisocyanates include aromatic diisocyanates, aliphatic diisocyanates, or combinations thereof. In some embodiments, the polyisocyanate component includes one or more aromatic diisocyanates. In some embodiments, the polyisocyanate component is essentially free or further completely free of aliphatic diisocyanates. In other embodiments, the polyisocyanate component includes one or more aliphatic diisocyanates. In some embodiments, the polyisocyanate component is essentially free or further completely free of aromatic diisocyanates.

[0013] Examples of useful polyisocyanates include aromatic diisocyanates such as 4,4'-methylenebis(phenyl isocyanate) (MDI), m-xylene diisocyanate (XDI), 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, phenylene-1,4-diisocyanate (PDI), phenylene-1,3-diisocyanate, naphthalene-1,5-diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), and toluene diisocyanate (TDI), and aliphatic diisocyanates such as isophorone diisocyanate (IPDI), 1,4-cyclohexyl diisocyanate (CHDI), decane-1,10-diisocyanate, lysine diisocyanate (LDI), 1,4-butane diisocyanate (BDI), isophorone diisocyanate (PDI), hexane diisocyanate (HDI), 1,4-bis(isocyanatomethyl)cyclohexane (1,4-H6XDI), and dicyclohexylmethane-4,4'-diisocyanate (H12MDI). Mixtures of two or more polyisocyanates may be used. In one embodiment, the diisocyanate used in the present invention comprises or consists of MDI.

[0014] Chain extender component The thermoplastic polyurethane composition of the present invention is optionally prepared using a chain extender component. Suitable chain extenders include relatively small polyhydroxy compounds, such as lower aliphatic or short-chain glycols having 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, neopentyl glycol, 1,4-cyclohexanedimethanol (CHDM), 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane (HEPP), hexamethylene diol, heptanediol, nonanediol, dodecanediol, 3-methyl-1,5-pentanediol, ethylenediamine, butanediamine, hexamethylenediamine, and hydroxyethylresorcinol (HER), pentaspiroglycol (PSG), hydroquinone bis(2-hydroxyethyl) ether hydroquinone (HQEE), dipropylene glycol (DPG), 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol (BEPD), etc., as well as mixtures thereof. In some embodiments, the chain extender includes BDO, HDO, 3-methyl-1,5-pentanediol, or a combination thereof.

[0015] In one embodiment of the present invention, the chain extender comprises or consists of 1,4-butanediol. In another embodiment, the chain extender component comprises or consists of 2-butyl-2-ethyl-1,3-propanediol. In another embodiment, the chain extender component comprises or consists of dipropylene glycol. In yet another embodiment, the chain extender comprises or consists of neopentyl glycol. In another embodiment, the chain extender component comprises a mixture of chain extenders selected from 1,4-butanediol, 2-butyl-2-ethyl-1,3-propanediol, dipropylene glycol, and neopentyl glycol.

[0016] The hard segment content of the thermoplastic polyurethane composition is defined as the total weight percentage of the diisocyanate component and the chain extender component. In some embodiments of the present invention, the thermoplastic polyurethane herein has a hard segment content of 49% to 80% by weight, for example 54% to 75% by weight.

[0017] In one embodiment of the present invention, the thermoplastic polyurethane comprises a reaction product of a polyether polyol and a polybutadiene polyol, a diisocyanate component, and optionally a chain extender component. In another embodiment, the thermoplastic polyurethane comprises a reaction product of a polyol component and a diisocyanate, the polyol component comprising a mixture of a polyether polyol and a polybutadiene polyol, the polyether polyol being at least 50% by weight of the polyol component. In such an embodiment, the polyether polyol exceeds 50% by weight of the polyol component. In another embodiment, the polyol component comprises a mixture of a polyether polyol and a polybutadiene polyol in a weight ratio of 90:10 to 40:60, for example 80:20 to 60:40, and still further for example 70:30 to 60:40.

[0018] In another embodiment of the present invention, the thermoplastic polyurethane comprises a reaction product of a polyol component and a diisocyanate component, the polyol component comprising or consisting of a mixture of poly(tetramethylene ether glycol) and an unsaturated polybutadiene diol with the diisocyanate component. In such an embodiment, the polyol component may comprise a mixture of poly(tetramethylene ether glycol) and polybutadiene diol in a weight ratio of 90:10 to 40:60, for example 80:20 to 60:40, and still further for example 70:30 to 60:40.

[0019] The thermoplastic polyurethane composition of the present invention can be produced using any process currently known or developed in the future. For example, in one embodiment, a "one-shot" process may be used, in which case the reactants (polyol component, diisocyanate, and optionally, a chain extender component) are added to an extruder reactor and reacted. In another embodiment, the thermoplastic polyurethane may be prepared using a prepolymer process. In the prepolymer process, the polyol intermediate generally reacts with an equivalent excess of one or more diisocyanates to form a prepolymer solution having free or unreacted diisocyanate therein. Subsequently, as described above, a chain extender is added in an equivalent amount equal to the isocyanate end groups as well as any free or unreacted diisocyanate compounds. Typically, the prepolymer route can be carried out in any conventional device including an extruder.

[0020] Optionally, it may be desirable to utilize catalysts such as stannous and other metal carboxylates and tertiary amines. Examples of suitable catalysts that particularly promote the reaction between the NCO groups of the diisocyanate and the hydroxy groups of the polyol and chain extender include conventional tertiary amines known from the prior art, such as triethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol, diazabicyclo[2.2.2]octane, etc., and in particular, organometallic compounds such as titanates, iron compounds, such as ferrous acetylacetonate, tin compounds, such as stannous diacetate, stannous dioctoate, stannous dilaurate, or dialkyltin salts of aliphatic carboxylic acids, such as dibutyltin diacetate, dibutyltin dilaurate, etc., phenylmercury propionate, lead octoate, iron acetylacetonate, magnesium acetylacetonate, or bismuth compounds, such as bismuth octoate, bismuth laurate, etc. xylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol, diazabicyclo[2.2.2]octane, etc. can be mentioned, and in particular, organometallic compounds such as titanates, iron compounds, such as ferrous acetylacetonate, tin compounds, such as stannous diacetate, stannous dioctoate, stannous dilaurate, or dialkyltin salts of aliphatic carboxylic acids, such as dibutyltin diacetate, dibutyltin dilaurate, etc., phenylmercury propionate, lead octoate, iron acetylacetonate, magnesium acetylacetonate, or bismuth compounds, such as bismuth octoate, bismuth laurate, etc.

[0021] Various types of optional components can be present during the polymerization reaction and / or can be incorporated into the TPU elastomers described above. These include, but are not limited to, antioxidants, biocides, compatibilizers, antistatic additives with electrical dissipative properties, fillers / reinforcing agents, flame retardants and fire retardants, fungicides, impact modifiers, pigments, colorants, plasticizers, polymers, rheology modifiers, slip additives, and UV stabilizers. All of the above additives may be used in effective amounts customary for these substances.

[0022] These additional additives can be incorporated into the components of the TPU resin, or into the reaction mixture of the TPU resin, into the preparation of the TPU resin, or after the production of the TPU resin. In another process, all of the materials can be mixed with the TPU resin and then melted or incorporated directly into the melt of the TPU resin.

[0023] The thermoplastic polyurethane composition of the present invention exhibits unexpected properties including a flexural modulus of at least 160 MPa measured according to ASTM D790, while showing the ability to withstand at least 30,000 low-temperature fatigue cycles measured at -10 °C according to ASTM D1052. In some embodiments, the thermoplastic polyurethane composition according to the present invention has a flexural modulus of at least 160 MPa or even 200 MPa and shows the ability to withstand at least 40,000 low-temperature fatigue cycles. Another unexpected property associated with the inventive thermoplastic polyurethane of the present invention is the transparency of such materials. In one embodiment, a material showing an unexpected flexural modulus and the ability to withstand low-temperature fatigue cycles is further transparent. In one embodiment, the thermoplastic polyurethane of the present invention shows a haze of 22% or less when measured according to ASTM D1003 on a 75-mil injection-molded plaque. The present invention also includes articles made of such thermoplastic polyurethanes showing these unique and unexpected properties and methods for making such articles by known methods such as molding or extrusion.

[0024] The thermoplastic polyurethane composition of the present invention can be used in various applications including industrial applications such as hoses and tubes as well as wires and cables, for example, high-pressure tubes, wires, and cable coatings / insulations, footwear applications such as running shoes, slip-resistant shoes, winter and summer sports goods and applications such as snowboards, ski equipment, mountain climbing equipment, kayak and rafting equipment, golf equipment, golf balls, cycling equipment, personal protective equipment and applications such as knee pads, helmets, and applications in personal electronic components, but are not limited thereto.

[0025] A series of thermoplastic polyurethane sample compositions were formed by reacting the components shown in Table 1. The isocyanate component for all samples is MDI.

Table 1-1

Table 1-2

[0026] The results in Table 1 show that the combination of poly(tetramethylene ether glycol) and polybutadiene diol provides an unexpected synergistic effect with respect to the flexural modulus and the ability to withstand cyclic deformation. When polybutadiene diol is added to a thermoplastic polyurethane composition containing a polyether polyol, it is generally expected that the flexural modulus will decrease, but as the data in Table 1 shows, the flexural modulus of the thermoplastic polyurethane containing this combination is unexpectedly high. In addition, the examples of the present invention can withstand a number of cyclic deformations.

[0027] As used herein, the transitional term "comprising", which is synonymous with "including", "containing", or "characterized by", is inclusive or open-ended and does not exclude additional, unrecited elements, or method steps. However, in each instance of the term "comprising" herein, this term is intended to also encompass, as alternative embodiments, the phrases "consisting essentially of" and "consisting of", where "consisting of" excludes any element or step not specified, and "consisting essentially of" allows for additional unrecited elements or steps that do not substantially affect the basic and novel characteristics of the composition or method being considered.

[0028] Although the invention has been described in connection with its preferred embodiments, it is to be understood that various modifications will be 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. For example, the present invention provides the following items. (Item 1) A thermoplastic polyurethane comprising (a) a polyol component comprising a mixture of a polyether polyol and a polybutadiene polyol, and (b) a diisocyanate component. (Item 2) The thermoplastic polyurethane according to Item 1, wherein the polyether polyol comprises or consists of poly(tetramethylene ether glycol), polypropylene glycol, polyethylene glycol, polyoxymethylene, or a mixture thereof. (Item 3) The thermoplastic polyurethane according to item 1 or 2, wherein the polybutadiene polyol contains or consists of an unsaturated polybutadiene polyol. (Item 4) (c) A chain extender component, and further comprising the thermoplastic polyurethane according to any one of items 1 to 3. (Item 5) The thermoplastic polyurethane according to any one of items 1 to 4, wherein the thermoplastic polyurethane has a hard segment content of 49% to 80% by weight, and the hard segment content is defined as the total weight of the diisocyanate component and the chain extender component. (Item 6) The thermoplastic polyurethane according to item 5, wherein the thermoplastic polyurethane has a hard segment content of 54% to 75% by weight. (Item 7) The thermoplastic polyurethane according to any one of items 4 to 6, wherein the chain extender component is selected from 1,4-butanediol, 2-butyl-2-ethyl-1,3-propanediol, dipropylene glycol, neopentyl glycol, and mixtures thereof. (Item 8) The thermoplastic polyurethane according to any one of items 1 to 7, wherein the polyol component contains at least 50% by weight of a polyether polyol. (Item 9) The thermoplastic polyurethane according to item 8, wherein the polyol component contains more than 50% by weight of a polyether polyol. (Item 10) The thermoplastic polyurethane according to any one of items 1 to 9, wherein the polyol component contains a mixture of a polyether polyol and an unsaturated polybutadiene polyol in a weight ratio of 90:10 to 40:60. (Item 11) The thermoplastic polyurethane according to item 10, wherein the polyol component contains a mixture of a polyether polyol and an unsaturated polybutadiene polyol in a weight ratio of 80:20 to 60:40. (Item 12) The thermoplastic polyurethane according to any one of Items 1 to 11, wherein the polyether polyol has a number average molecular weight of 500 to 3000 as measured by assay of terminal functional groups. (Item 13) The thermoplastic polyurethane according to Item 12, wherein the polyether polyol has a molecular weight of 1000 to 2500 as measured by assay of terminal functional groups. (Item 14) The thermoplastic polyurethane according to any one of Items 1 to 13, wherein the diisocyanate component contains or consists of an aromatic diisocyanate. (Item 15) The thermoplastic polyurethane according to any one of Items 1 to 14, wherein the diisocyanate component contains or consists of 4,4'-methylenebis(phenyl isocyanate). (Item 16) The thermoplastic polyurethane according to any one of Items 1 to 15, wherein the polybutadiene polyol contains or consists of polybutadiene diol. (Item 17) The thermoplastic polyurethane according to any one of Items 1 to 16, wherein the polyether polyol contains poly(tetramethylene ether glycol). (Item 18) The thermoplastic polyurethane according to any one of Items 1 to 17, wherein the polyether polyol component contains a mixture of poly(tetramethylene ether glycol) and poly(propylene glycol) end-capped with ethylene oxide. (Item 19) The thermoplastic polyurethane according to any one of Items 1 to 16, wherein the polyether polyol contains polypropylene glycol. (Item 20) A thermoplastic polyurethane, (a) A polyol component comprising a mixture of a polyether polyol and a polybutadiene polyol, wherein the polyether polyol is at least 50% by weight of the polyol component, and the polyether polyol comprises or consists of poly(tetramethylene ether glycol), and the polyol component, (b) A thermoplastic polyurethane comprising a reaction product of a diisocyanate component. (Item 21) (c) A chain extender component, and the thermoplastic polyurethane according to Item 20, further comprising the same. (Item 22) The thermoplastic polyurethane according to Item 20 or 21, wherein the thermoplastic polyurethane has a hard segment content of 49% to 80% by weight or 54% to 75% by weight, and the hard segment content is defined as the total weight of the diisocyanate component and the chain extender component. (Item 23) The thermoplastic polyurethane according to Item 21 or 22, wherein the chain extender component is selected from 1,4-butanediol, 2-butyl-2-ethyl-1,3-propanediol, dipropylene glycol, neopentyl glycol, or a mixture thereof. (Item 24) The thermoplastic polyurethane according to any one of Items 20 to 23, wherein the polyether polyol consists of poly(tetramethylene ether glycol). (Item 25) The thermoplastic polyurethane according to any one of Items 20 to 23, wherein the polyether polyol comprises or consists of a mixture of poly(tetramethylene ether glycol) and poly(propylene glycol) end-capped with ethylene oxide. (Item 26) The thermoplastic polyurethane according to any one of Items 20 to 25, wherein the polybutadiene polyol comprises or consists of polybutadiene diol. (Item 27) The thermoplastic polyurethane according to any one of items 20 to 26, wherein the polyol component contains a mixture of the polyether polyol and polybutadiene diol in a weight ratio of 90:10 to 60:40 or 80:20 to 60:40. (Item 28) The thermoplastic polyurethane according to any one of items 20 to 27, wherein the polybutadiene diol is unsaturated. (Item 29) The thermoplastic polyurethane according to any one of items 20 to 28, wherein the diisocyanate component contains or consists of an aromatic diisocyanate. (Item 30) The thermoplastic polyurethane according to item 29, wherein the diisocyanate component contains or consists of 4,4'-methylenebis(phenyl isocyanate). (Item 31) An article made from the thermoplastic polyurethane composition according to any one of items 1 to 30.

Claims

[Claim 1] The invention described in the specification.

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