A special aliphatic thermoplastic polyurethane elastomer material and a preparation method thereof

Abstract

The application discloses a special aliphatic thermoplastic polyurethane elastomer material and a preparation method thereof, and relates to the technical field of polymer materials.The raw materials of the thermoplastic polyurethane elastomer material include polyglycol, diisocyanate, a composite chain extender and a catalyst; the R value of the special aliphatic thermoplastic polyurethane elastomer material is 1.00-1.05; and the hard segment content is 30-50 wt%; wherein the polyglycol contains a cyclohexane ester ring structure and has a number average molecular weight of 1000-5000 g / mol; the diisocyanate is an aliphatic diisocyanate containing a benzene ring; and the composite chain extender is a mixture composed of BACP and 2,5-DAN in an equimolar ratio.The special aliphatic thermoplastic polyurethane elastomer material has the unique full-aliphatic ring structure of "the cyclohexane aliphatic ring of PSCH + the steric aliphatic NCO of TMXDI + the double aliphatic ring composite chain extension of BACP / 2,5-DAN", so that the material has excellent thermal performance, mechanical performance, oil resistance and weather resistance, the comprehensive performance is significantly enhanced, and the material is suitable for large-scale popularization and application in complex environments.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, mainly to the field of polyurethane elastomer materials technology, and specifically to a special aliphatic thermoplastic polyurethane elastomer material and its preparation method. Background Technology

[0002] Polyurethane (PU), short for polyurethane, is a molecular structure containing repeating urethane segments (-NHCOO-) and urea bonds (-NHCONH-), composed of flexible soft segments and rigid hard segments (AB). n Linear block copolymers. Thermoplastic polyurethane elastomer (TPU), as one of the many forms of polyurethane materials, has an elastic modulus (E) between that of plastics and rubber. It has advantages such as low processing cost, good compression resistance, low density, good solvent resistance, and good aging resistance. It is widely used in automotive seals, industrial hoses, high-end cables, military engineering, and the electronics industry. It is one of the six synthetic materials with development potential.

[0003] However, while ordinary aliphatic TPUs possess advantages such as low yellowing and good weather resistance, achieving a balance between heat resistance, oil resistance, and mechanical properties is challenging. Most aliphatic TPUs can only maintain a long-term operating temperature of 80-100℃, and are prone to thermal degradation in environments above 120℃. Furthermore, they exhibit poor oil swelling resistance (easily experiencing volume expansion and decreased mechanical properties in oily media). Conventional aromatic TPUs, while offering slightly improved heat resistance, suffer from poor weather resistance and a tendency to yellow, failing to meet the comprehensive performance requirements of high-end applications. Simultaneously, existing TPUs are mostly prepared using a single chain extender. A single flexible chain extender leads to insufficient material strength and heat resistance, while a single rigid chain extender reduces toughness and makes the material brittle, further limiting TPU applications in high-end, high-temperature, and oil-resistant scenarios. Therefore, it is essential to implement corresponding modification measures in molecular structure design, raw material selection, and preparation processes to achieve a synergistic improvement in heat resistance, oil resistance, weather resistance, and mechanical properties, thereby expanding the application range of TPUs and extending their service life.

[0004] Chinese invention patent application CN202010912712.6 discloses a thermoplastic polyurethane elastomer with excellent heat resistance and its preparation method. This thermoplastic polyurethane elastomer, prepared from polyester polyol, diisocyanate, and diol chain extender, exhibits strong aging resistance and a high softening temperature, but its oil resistance and toughness need improvement, and it fails to achieve a balance between rigidity and flexibility in its molecular chains. Chinese invention patent application CN201510433964.X discloses an oil-resistant and low-temperature-resistant thermoplastic polyurethane elastomer film and its preparation method. While the thermoplastic polyurethane elastomer prepared by this invention shows significantly improved oil resistance compared to conventional TPU and excellent low-temperature toughness, it is prone to thermo-oxidative aging and insufficient thermal stability during long-term high-temperature use, making it difficult to meet the oil-resistant sealing requirements under high-temperature conditions.

[0005] Therefore, there is an urgent need to develop a special thermoplastic polyurethane elastomer material with excellent heat resistance, oil resistance, weather resistance and mechanical properties to meet the complex application environment of today, which will play a positive role in the large-scale application of thermoplastic polyurethane elastomer materials. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of poor heat resistance, oil resistance, weather resistance, and mechanical property balance, and poor overall performance of existing thermoplastic polyurethane elastomer materials, and to propose a special aliphatic thermoplastic polyurethane elastomer material and its preparation method.

[0007] To achieve the above objectives, the present invention provides a special aliphatic thermoplastic polyurethane elastomer material, the raw materials of which include polydiol, diisocyanate, composite chain extender and catalyst; the R value (the ratio of the total molar number of isocyanate to hydroxyl and amino groups in the material) of the special aliphatic thermoplastic polyurethane elastomer material is 1.00~1.05, and the content of hard segments is 30~50 wt%; The polydiol contains a cyclohexane ester ring structure and has a number average molecular weight of 1000-5000 g / mol; the diisocyanate is an aliphatic diisocyanate containing a benzene ring. The composite chain extender is a mixture of 1,3-bis(4-aminocyclohexyl)propane (BACP) and 2,5-diaminonorbornene (2,5-DAN) in an equimolar ratio (1:1).

[0008] This invention discloses a special aliphatic thermoplastic polyurethane elastomer material. It not only utilizes a polydiol containing a cyclohexane alicyclic structure to impart excellent hydrolysis resistance, oil resistance, and toughness to the polyurethane elastomer, enhancing the rigidity of the soft segment, but also leverages the sterically hindered aliphatic structure of a benzene-containing aliphatic diisocyanate to combine aromatic ring rigidity with aliphatic weather resistance, significantly improving the yellowing defect of polyurethane. Furthermore, the isocyanate group it contains has milder activity, ensuring a stable and controllable reaction. Simultaneously, it employs a composite chain extender composed of equimolar amounts of BACP and 2,5-DAN for chain extension treatment, thereby enabling the utilization of the propylene oxide in BACP... The alkyl flexible bridge improves the mobility of hard segment chains, and the bicyclic rigid structure in 2,5-DAN increases the rigidity of hard chains. It can also form a synergistic effect with the mildly active isocyanate group, achieving precise control of the rigid-flexible balance of hard segments, optimizing the crystal size of hard segments, and increasing the degree of microphase separation by generating dense urea bonds and hydrogen bonds. This significantly improves the mutual adverse effects between polydiol and diisocyanate, resulting in a significant improvement in the heat resistance, oil resistance, weather resistance, and mechanical property balance of the obtained thermoplastic polyurethane elastomer. The comprehensive performance of the thermoplastic polyurethane elastomer is significantly enhanced, making it suitable for large-scale application in complex environments.

[0009] The amounts of the polydiol, diisocyanate, and composite chain extender can all be calculated using the R value and the hard segment content, where R = n(NCO). 二异氰酸酯 / [n(OH) 聚二元醇 + n(OH) 扩链剂 Preferably, the amount of catalyst used is 0.01 to 0.03 wt% of the total amount of raw materials.

[0010] Preferably, the polydiol is one or more of 1,4-cyclohexanediethanol, 1,3-cyclohexanediethanol, 1,4-cyclohexanediol (1,4-CHD), cyclohexane-1,4-dicarboxylic acid bis(hydroxyethyl) ester, and polysaccharide-1,4-cyclohexanediethanol diol (PSCH); most preferably, the polydiol is polysaccharide-1,4-cyclohexanediethanol diol (PSCH).

[0011] Preferably, the number-average molecular weight of the polydiol is 1500-2500 g / mol.

[0012] Preferably, the isocyanate (NCO) content in the diisocyanate is 32.0~33.5wt%; more preferably, it is 32.7±0.5wt%.

[0013] Preferably, the diisocyanate is m-phenylenedimethyl diisocyanate (m-XDI), hydrogenated m-phenylenedimethyl diisocyanate (H6XDI), or hydrogenated diphenylmethane diisocyanate (H6XDI).12 One or more of MDI, tetramethyl isophthalimide diisocyanate (TMXDI); most preferably, the diisocyanate is tetramethyl isophthalimide diisocyanate (TMXDI).

[0014] Preferably, the catalyst is one or more of dibutyltin dilaurate (DBTDL) and organic bismuth catalyst; most preferably, it is dibutyltin dilaurate (DBTDL).

[0015] Preferably, the R value (the ratio of the total molar number of isocyanates to hydroxyl and amino groups in the material) of the special aliphatic thermoplastic polyurethane elastomer material is 1.02.

[0016] Preferably, the hard segment content of the special aliphatic thermoplastic polyurethane elastomer material is 40%.

[0017] To achieve the above objectives, the present invention further provides a method for preparing a special aliphatic thermoplastic polyurethane elastomer material, comprising the following steps: (1) Prepolymerization reaction: The polydiol is mixed with a portion of the composite chain extender and dehydrated for 1.5-2.5 h at 100-110℃ and vacuum degree ≤-0.095MPa. Then, the temperature is lowered to 65-75℃, the catalyst and diisocyanate are added, and the mixture is stirred evenly. The prepolymerization reaction is carried out for 30-50 min to obtain the end-capped prepolymer. (2) Chain extension reaction: Cool the end-capped prepolymer to 55-65℃, add the remaining composite chain extender, stir and react for 5-10 minutes until the viscosity of the system increases, and obtain the thermoplastic polyurethane elastomer semi-finished product; (3) Molding and curing: The material will be molded and cured at 95-120℃ to obtain a special aliphatic thermoplastic polyurethane elastomer material product.

[0018] This invention discloses a method for preparing a special aliphatic thermoplastic polyurethane elastomer material. The method employs a semi-prepolymer stepwise chain extender process, achieving effective control over the polymerization reaction of the polyurethane elastomer by precisely controlling the timing and amount of the composite chain extender. This weakens the adverse interactions between the polydiol and diisocyanate, resulting in a polyurethane elastomer with better rigidity-flexibility balance, and higher uniformity in heat resistance, oil resistance, weather resistance, and mechanical properties. Furthermore, the preparation method offers good controllability, mild reaction conditions, and simple steps, making it suitable for large-scale production of special aliphatic thermoplastic polyurethane elastomer materials.

[0019] In step (1), preferably, the R value (ratio of the total molar number of isocyanate to hydroxyl and amino groups) of the end-capped prepolymer is 1.6 to 2.0; more preferably, the R value of the end-capped prepolymer is 1.8. By adjusting the R value of the end-capped prepolymer, the viscosity of the prepolymer can be reduced, and excessive chain growth and gelation in the prepolymerization stage can be avoided, thereby affecting the product performance.

[0020] In step (1), the specific amount of the composite chain extender added is calculated from the R value of the end-capped prepolymer.

[0021] The beneficial effects of this invention are: 1. The thermoplastic polyurethane elastomer material of the present invention utilizes the cyclohexane alicyclic structure in polydiol to endow polyurethane elastomer with excellent hydrolysis resistance, oil resistance and toughness, and improve the rigidity of the soft segment; it utilizes the sterically hindered aliphatic structure of aliphatic diisocyanate containing benzene ring to combine the rigidity of aromatic ring and the weather resistance of aliphatic, effectively improving the defect of polyurethane's easy yellowing, and the isocyanate contained therein has a milder activity, which also ensures the stability and controllability of the reaction.

[0022] 2. The thermoplastic polyurethane elastomer material of the present invention uses a composite chain extender composed of BACP and 2,5-DAN in equal molar amounts for chain extension treatment. The propane flexible bridge in BACP improves the mobility of hard chain segments and the double-ring rigid structure in 2,5-DAN increases the rigidity of hard chains.

[0023] 3. The composite chain extender in the thermoplastic polyurethane elastomer material of the present invention can form a synergistic effect with the mildly active isocyanate group, thereby achieving precise control of the rigid-flexible balance of the hard segment, optimizing the crystal size of the hard segment, and increasing the degree of microphase separation by generating dense urea bonds and hydrogen bonds, thus significantly improving the mutual adverse effects between polydiol and diisocyanate.

[0024] 4. The thermoplastic polyurethane elastomer material of this invention has significantly improved the balance of heat resistance, oil resistance, weather resistance and mechanical properties. The comprehensive performance of thermoplastic polyurethane elastomer has been significantly enhanced, making it suitable for large-scale application in more complex environments.

[0025] 5. The method for preparing thermoplastic polyurethane elastomer material of the present invention achieves effective control over the polymerization reaction of polyurethane elastomer, weakens the adverse effects between polydiol and diisocyanate, thereby making the prepared polyurethane elastomer have better rigidity-flexibility balance, and higher balance of heat resistance, oil resistance, weather resistance and mechanical properties. Attached Figure Description

[0026] Figure 1 The image shows the FT-IR curve of the special aliphatic thermoplastic polyurethane elastomer material in Example 1 of this invention. Detailed Implementation

[0027] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0028] Unless otherwise specified, all raw materials used in the embodiments of the present invention are commercially available products.

[0029] Example 1

[0030] A special aliphatic thermoplastic polyurethane elastomer material with an R value of 1.02 and a hard segment content of 40% comprises the following raw materials: polydiol (PSCH, number average molecular weight of 2000 g / mol) and diisocyanate (TMXDI, NCO content of 32.7 wt%), a composite chain extender (calculated by R value and hard segment content) and 0.01 wt% catalyst (DBTDL). The specific preparation method is as follows: (1) Prepolymerization reaction: Polydiol was mixed with a portion of the composite chain extender (39.6% of the total amount, calculated by the R value of the end-capped prepolymer), and dehydrated for 2 hours at 105°C and vacuum degree -0.1MPa. Then, the temperature was lowered to 70°C, and a catalyst and diisocyanate were added. The mixture was stirred evenly and prepolymerized for 40 minutes to obtain the end-capped prepolymer (R value 1.8). (2) Chain extension reaction: Cool the end-capped prepolymer to 60°C, add the remaining composite chain extender (dropping time 4 min), stir the reaction until the viscosity of the system increases (3 min), and obtain the thermoplastic polyurethane elastomer semi-finished product; (3) Molding and curing: Pour the thermoplastic polyurethane elastomer semi-finished product into a mold preheated to 100°C, first cure at 105°C for 2 hours, then heat to 110°C for 2 hours, and then cool naturally to demold to obtain a special aliphatic thermoplastic polyurethane elastomer material product.

[0031] Examples 2-6

[0032] A special aliphatic thermoplastic polyurethane elastomer material is prepared using the same raw material weight parts and specific preparation method as in Example 1, except that the number-average molecular weight of PSCH is different. The specific number-average molecular weight of PSCH is shown in the table below:

[0033] Examples 7-12

[0034] A special aliphatic thermoplastic polyurethane elastomer material is prepared using the same raw material weight proportions and specific preparation method as in Example 1, except that the NCO content in TMXDI is different. The specific NCO content in TMXDI is shown in the table below:

[0035] Examples 13-16

[0036] A special aliphatic thermoplastic polyurethane elastomer material, with the same raw material formulation and specific preparation method as in Example 1, differs only in the R value of the end-capped prepolymer (only the amount of composite chain extender in steps (1) and (2) was adjusted, but the total amount of composite chain extender remained unchanged). The R values ​​of the end-capped prepolymer are shown in the table below:

[0037] Examples 17-18

[0038] A special aliphatic thermoplastic polyurethane elastomer material is prepared using the same method as in Example 1, except that the R-value of the special aliphatic thermoplastic polyurethane elastomer material is different (the total amount of diisocyanate and composite chain extender is adjusted according to the R-value while keeping the amount of polydiol constant). The R-values ​​of the special aliphatic thermoplastic polyurethane elastomer material are shown in the table below:

[0039] Examples 19-20

[0040] A special aliphatic thermoplastic polyurethane elastomer material is prepared using the same method as in Example 1, except that the hard segment content of the special aliphatic thermoplastic polyurethane elastomer material is different (the total amount of diisocyanate and composite chain extender is adjusted according to the hard segment content while keeping the amount of polydiol constant). The hard segment content of the special aliphatic thermoplastic polyurethane elastomer material is shown in the table below:

[0041] Comparative Examples 1-2

[0042] A thermoplastic polyurethane elastomer material, with the same raw material weight parts and specific preparation method as in Example 1, differs only in the molar ratio of BACP and 2,5-DAN, as shown in the table below:

[0043] Comparative Example 3

[0044] A thermoplastic polyurethane elastomer material, the raw material weight parts and specific preparation method are the same as those in Example 1, the only difference being that the number average molecular weight of PSCH is 500 g / mol.

[0045] Comparative Example 4

[0046] A thermoplastic polyurethane elastomer material, the raw material weight parts and specific preparation method are the same as those in Example 1, the only difference being that the number average molecular weight of PSCH is 6000 g / mol.

[0047] Comparative Example 5

[0048] A thermoplastic polyurethane elastomer material, the raw materials by weight and the specific preparation method are the same as in Example 1, the only difference being that the diisocyanate is isoflurone diisocyanate.

[0049] Comparative Example 6

[0050] A thermoplastic polyurethane elastomer material, the raw material weight parts and specific preparation method are the same as those in Example 1, the only difference being that: the polydiol is polycarbonate diol.

[0051] Comparative Example 7

[0052] A thermoplastic polyurethane elastomer material is prepared in the same way as in Example 1, except that the R value of the special aliphatic thermoplastic polyurethane elastomer material is 1.10 (when the content of polydiol remains unchanged, only the total amount of diisocyanate and composite chain extender is adjusted).

[0053] Comparative Example 8

[0054] A thermoplastic polyurethane elastomer material is prepared in the same way as in Example 1, except that the R value of the special aliphatic thermoplastic polyurethane elastomer material is 0.93 (when the content of polydiol remains unchanged, only the total amount of diisocyanate and composite chain extender is adjusted).

[0055] Comparative Example 9

[0056] A thermoplastic polyurethane elastomer material is prepared in the same way as in Example 1, except that the hard segment content of the special aliphatic thermoplastic polyurethane elastomer material is 20wt% (when the polydiol content remains unchanged, only the total amount of diisocyanate and composite chain extender is adjusted).

[0057] Comparative Example 10

[0058] A thermoplastic polyurethane elastomer material is prepared in the same way as in Example 1, except that the hard segment content of the special aliphatic thermoplastic polyurethane elastomer material is 60wt% (when the polydiol content remains unchanged, only the total amount of diisocyanate and composite chain extender is adjusted).

[0059] Comparative Example 11

[0060] A thermoplastic polyurethane elastomer material, with the same raw material weight parts as in Example 1, differing only in the specific preparation method, including the following: (1) End-capping reaction: Polydiol, catalyst and diisocyanate were stirred evenly and prepolymerized at 70°C for 40 min to obtain end-capped prepolymer (R value 1.8). (2) Chain extension reaction: Cool the end-capped prepolymer to 60°C, add all the composite chain extenders (dropping time 4 min), stir the reaction until the viscosity of the system increases (3 min), and obtain the thermoplastic polyurethane elastomer semi-finished product; (3) Molding and curing: Pour the thermoplastic polyurethane elastomer semi-finished product into a mold preheated to 100°C, first cure at 105°C for 2 hours, then heat to 110°C for 2 hours, and then cool naturally to demold to obtain a special aliphatic thermoplastic polyurethane elastomer material product.

[0061] Experimental Example 1: The thermoplastic polyurethane elastomer material prepared in Example 1 was subjected to infrared spectroscopy detection, and the FT-IR curve is shown below. Figure 1 As shown.

[0062] analyze Figure 1 It can be seen that: in the range of 3300-3500cm - The NH stretching vibration peak appears at position ¹, between 1700 and 1750 cm⁻¹. - A strong and sharp C=O stretching vibration peak appears at ¹, between 1530 and 1550 cm⁻¹. - A combined peak of NH bending and CN stretching appears at ¹, in the range of 1200–1250 cm⁻¹. - A COC stretching vibration peak appears at position ¹, and is observed at 2270 cm⁻¹. - The absence of a distinct absorption peak near ¹ indicates that the isocyanate has reacted completely, and the target polyurethane structure has been successfully prepared. (2900–3000 cm⁻¹) - A distinct CH stretching vibration peak appears at position ¹, with peak shape and intensity consistent with alicyclic / aliphatic compounds; the peak is located at 1000–1500 cm⁻¹. - The fingerprint region exhibits a complex peak shape, consistent with the multi-ring vibrational modes of the full alicyclic system, further confirming the structural characteristics of the sample. Furthermore, at 1600 cm⁻¹... - A weak absorption peak was observed near ¹, which corresponds to the skeletal vibration of the benzene ring in TMXDI, consistent with the structural characteristics of the raw material.

[0063] Experimental Example 2: The thermal properties (Vicat softening point (T)) of the thermoplastic polyurethane elastomer materials prepared in Examples 1-20 and Comparative Examples 1-11 were compared. vs (Refer to national standard GB / T 1633-2000 "Determination of Vicat Softening Temperature (VST) of Thermoplastic Plastics"); 5% thermal decomposition temperature (T d5%ISO 11358-1:2022 "Plastics - Thermogravimetric analysis (TGA) - Part 1 - General"; Glass transition temperature (T g The test was conducted according to GB / T 19466.2-2004 "Differential Scanning Calorimetry (DSC) for Plastics - Part 2: Determination of Glass Transition Temperature", and the test results are shown in Table 1.

[0064] Table 1. Thermal performance test results of TPU in the examples and comparative examples.

[0065] Experimental Example 3: The mechanical properties (Shore A hardness; tensile strength; elongation at break) of the thermoplastic polyurethane elastomer materials prepared in Examples 1-20 and Comparative Examples 1-11 were tested. The Shore A hardness was tested according to GB / T 531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness tester method (Shore hardness)", and the tensile strength and elongation at break were tested according to GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The test results are shown in Table 2.

[0066] Table 2. Mechanical property test results of TPU in the examples and comparative examples.

[0067] Experiment Example 4: The oil resistance of the thermoplastic polyurethane elastomer materials prepared in Examples 1-20 and Comparative Examples 1-11 was tested according to GB / T 1690-2010 "Test Method for Liquid Resistance of Vulcanized Rubber or Thermoplastic Rubber" and ASTM D471-16 (mass change was measured by weighing with an analytical balance, and volume change was measured by the water displacement method). After immersing the samples in IRM903 standard mineral oil (25°C) for 30 days, the rate of mass change (Δ) was measured. m ); Tensile strength change rate (Δ σb ); Change in elongation at break (Δ εb ); Volume change rate (Δ V Shore A hardness change (ΔH) A The test results are shown in Table 3.

[0068] Table 3. Mechanical property test results of TPU after oil immersion in the examples and comparative examples.

[0069] Experimental Example 5

[0070] The weather resistance of the thermoplastic polyurethane elastomer materials prepared in Examples 1-20 and Comparative Examples 1-11 was tested. The samples were subjected to xenon lamp accelerated aging for 1000 h according to GB / T 16422.2-2014. The yellowing index was tested according to GB / T2409-2023, the rate of change of mechanical properties was tested according to GB / T 528-2009, the change in hardness was tested according to GB / T 531.1-2021, and the rate of change in mass was tested according to GB / T 1690-2010. The rate of change in mass (Δ) was measured. m ); Tensile strength change rate (Δ σb ); Change in elongation at break (Δ εb Yellowing index (Δ) YI Shore A hardness change (ΔH) A The test results are shown in Table 4.

[0071] Table 4. Mechanical property test results of TPU after xenon lamp aging in the examples and comparative examples.

[0072] Analysis of the experimental results shows that the special aliphatic thermoplastic polyurethane elastomer material prepared by this invention possesses excellent thermal properties, mechanical properties, oil resistance, and weather resistance by constructing a unique all-alicyclic structure on the polyurethane main chain: "PSCH cyclohexane alicyclic ring + TMXDI sterically hindered aliphatic NCO + BACP / 2,5-DAN bicycloalicyclic composite chain extender". The example material exhibits a moderate Vicat softening temperature, good thermal stability, and a balanced match between tensile strength and elongation at break. After immersion in IRM903 standard mineral oil, it shows low performance degradation and excellent dimensional stability. Even after accelerated aging under a xenon lamp, it maintains a high retention rate of mechanical properties and minimal change in the yellowing index. Compared with the comparative examples, the example material achieves the best balance between heat resistance, mechanical strength, oil resistance, and weather resistance, resulting in significantly superior overall performance. It can meet the requirements of high-end oil resistance, weather resistance, heat resistance, and long-term stable use, and has good application prospects.

[0073] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A special aliphatic thermoplastic polyurethane elastomer material, characterized in that, The raw materials include polydiol, diisocyanate, composite chain extender, and catalyst; the R value of the special aliphatic thermoplastic polyurethane elastomer material is 1.00~1.05, and the hard segment content is 30~50 wt%. The polydiol contains a cyclohexane ester ring structure and has a number average molecular weight of 1000-5000 g / mol; the diisocyanate is an aliphatic diisocyanate containing a benzene ring. The composite chain extender is a mixture of 1,3-bis(4-aminocyclohexyl)propane and 2,5-diaminonorbornene in equimolar ratio.

2. The special aliphatic thermoplastic polyurethane elastomer material according to claim 1, characterized in that, The polydiol is one or more of 1,4-cyclohexanediethanol, 1,3-cyclohexanediethanol, 1,4-cyclohexanediol, cyclohexane-1,4-dicarboxylic acid bis(hydroxyethyl) ester, and polysaccharide-1,4-cyclohexanediethanol diol; preferably polysaccharide-1,4-cyclohexanediethanol diol.

3. The special aliphatic thermoplastic polyurethane elastomer material according to claim 1, characterized in that, The number-average molecular weight of the polydiol is 1500-2500 g / mol.

4. The special aliphatic thermoplastic polyurethane elastomer material according to claim 1, characterized in that, The diisocyanate contains 32.0 to 33.5 wt% isocyanate; more preferably 32.7 ± 0.5 wt%.

5. The special aliphatic thermoplastic polyurethane elastomer material according to claim 1, characterized in that, The diisocyanate is one or more of isophthalic diisocyanate, hydrogenated isophthalic diisocyanate, hydrogenated diphenylmethane diisocyanate, and tetramethyl isophthalimide diisocyanate; preferably tetramethyl isophthalimide diisocyanate.

6. The special aliphatic thermoplastic polyurethane elastomer material according to claim 1, characterized in that, The catalyst is one or more of dibutyltin dilaurate and organic bismuth catalyst; the most preferred is dibutyltin dilaurate.

7. The special aliphatic thermoplastic polyurethane elastomer material according to claim 1, characterized in that, The R-value of the special aliphatic thermoplastic polyurethane elastomer material is 1.

02.

8. The special aliphatic thermoplastic polyurethane elastomer material according to claim 1, characterized in that, The hard segment content is 40 wt%.

9. A method for preparing the special aliphatic thermoplastic polyurethane elastomer material according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Prepolymerization reaction: The polydiol is mixed with a portion of the composite chain extender and dehydrated for 1.5-2.5 h at 100-110℃ and vacuum degree ≤-0.095MPa. Then, the temperature is lowered to 65-75℃, the catalyst and diisocyanate are added, and the mixture is stirred evenly. The prepolymerization reaction is carried out for 30-50 min to obtain the end-capped prepolymer. (2) Chain extension reaction: Cool the end-capped prepolymer to 55-65℃, add the remaining composite chain extender, stir and react for 5-10 minutes until the viscosity of the system increases, and obtain the thermoplastic polyurethane elastomer semi-finished product; (3) Molding and curing: The thermoplastic polyurethane elastomer semi-finished product is molded and cured at 95-120℃ to obtain special aliphatic thermoplastic polyurethane elastomer material products.

10. The method for preparing the special aliphatic thermoplastic polyurethane elastomer material according to claim 9, characterized in that, The R value of the end-capped prepolymer in step (1) is 1.6 to 2.0; preferably, the R value of the end-capped prepolymer is 1.8.

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