Thermoplastic polyurethane elastomer as well as preparation method and application thereof

Abstract

The invention discloses a thermoplastic polyurethane elastomer as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The thermoplastic polyurethane elastomer comprises bio-based polyol, diisocyanate, a chain extender, an anti-hydrolysis agent, a nucleating agent and an antioxidant, the specific polyol and isocyanate are subjected to nucleophilic addition reaction, then the chain extender is mixed and compounded, the reaction process of the polyol and the isocyanate is guaranteed, and meanwhile the anti-hydrolysis performance of the thermoplastic polyurethane elastomer is improved. Due to the selection of the composite chain extender, the material is endowed with flame retardance, the migration rate of the chain extender is reduced and the like, and the light transmittance of the material is improved while the rebound resilience and the mechanical property of the material are not reduced by continuously mixing other auxiliaries.

Description

Technical Field

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

[0002] Thermoplastic polyurethane (TPU) is a multifunctional thermoplastic polymer composed of hard and soft segments. Due to its excellent tensile strength, toughness, tear resistance, and dimensional stability, it is widely used in footwear, medical devices, automotive parts, and electronic equipment components. Its synthesis processes mainly include bulk polymerization and solution polymerization. Bulk polymerization is further divided into prepolymerization and one-step polymerization. The former produces more stable products but is more complex, while the latter has a simpler process suitable for large-scale production. Solution polymerization involves a mild and easily controlled reaction, making it suitable for preparing products with special properties, but it suffers from high solvent recovery costs and significant environmental impact. In addition, there are derivative processes such as melt polycondensation and reactive extrusion, each suitable for preparing products with different performance requirements.

[0003] However, thermoplastic polyurethane (TPU) often suffers from insufficient resilience due to its low crystallinity, while high-resilience products suffer from poor transparency due to high hard segment regularity, which can also negatively impact production efficiency. For example, Chinese patent application CN117659348A discloses a high-resilience thermoplastic polyurethane elastomer, its preparation method, and its application. The polyurethane elastomer comprises the following components in the following weight ratios: 44-85 wt% polypolyol, preferably 50-75 wt%; 15-45 wt% diisocyanate, preferably 20-35 wt%; 1-10 wt% chain extender, preferably 5-10 wt%; and 0.1-1 wt% anti-hydrolysis agent, preferably 0.1-0.5 wt%.

[0004] CN112724652A discloses a highly transparent thermoplastic polyurethane elastomer for electronic products and its preparation method. The thermoplastic polyurethane elastomer comprises the following components by weight: 60-90 parts by weight of TPU particles, 20-40 parts by weight of polypropylene, 10-30 parts by weight of polycarbonate, 1-5 parts by weight of sorbitol nucleating agent, 1-5 parts by weight of phosphate ester nucleating agent, and 1-3 parts by weight of antioxidant.

[0005] The polyurethane elastomers in the above technical solutions have poor resilience and require the addition of flame retardants to improve the flame retardant properties of the materials, without taking into account the degradability of the materials.

[0006] Chinese patent application CN116162220A discloses a thermoplastic polyurethane elastomer material and its preparation method. The thermoplastic polyurethane elastomer material comprises 25-45 wt% aliphatic diisocyanate, 40-65 wt% macromolecular diol, 4-25 wt% chain extender A and chain extender B, and 0.01-0.2 wt% catalyst. It is compounded with chain extenders containing halogen or phosphorus flame retardants and other chain extenders; however, the chain extenders are easily migrating components within the system, thus affecting the long-term usability of the material.

[0007] In summary, the balance between transparency and resilience, flame retardancy and degradability, and the balance between chain extenders and migration rate in thermoplastic polyurethane are all problems that still need to be solved. Summary of the Invention

[0008] To address the above problems, this invention provides a thermoplastic polyurethane elastomer, its preparation method, and its application. Through a specific nucleophilic addition reaction of polyol and isocyanate in this invention, followed by mixing and compounding a chain extender, the reaction process of polyol and isocyanate is ensured. At the same time, the selection of the compound chain extender also endows the material with flame retardant properties and reduces the migration rate of the chain extender. Further mixing of other additives improves the light transmittance of the material without reducing its resilience and mechanical properties.

[0009] This invention provides a thermoplastic polyurethane elastomer, wherein the thermoplastic polyurethane elastomer has a light transmittance of 94-99%, a turbidity of 1.0-1.7%, a resilience of 98-99.9%, and a flame retardancy rating of V1; the thermoplastic polyurethane elastomer has a weight retention of 45-55% after 60 days; the thermoplastic polyurethane elastomer has a 300% tensile compressive strength of 10-15 N, a tensile strength of 44-50 MPa, and a tear strength of 145-170 MPa; the thermoplastic polyurethane elastomer has a hydrolysis resistance of 80-85%; and the migration rate of the chain extender in the thermoplastic polyurethane elastomer is 0.90-0.97%.

[0010] Furthermore, the thermoplastic polyurethane elastomer includes bio-based polyols, diisocyanates, chain extenders, anti-hydrolysis agents, nucleating agents, and antioxidants.

[0011] Furthermore, the components and their contents of the thermoplastic polyurethane elastomer are as follows: Bio-based polyols: 40-75 parts by weight; Diisocyanate: 15-35 parts by weight; Chain extender: 5-15 parts by weight; Anti-hydrolysis agent: 0.1-0.5 parts by weight; Nucleating agent: 1-3 parts by weight; Antioxidant: 0.5-1 parts by weight; Catalyst: 0.01-0.05 parts by weight.

[0012] Furthermore, the bio-based polyol is a polycarbonate-macrolide copolymer polyol and a polycaprolactone-lactide copolymer polyol.

[0013] Furthermore, the mass ratio of the polycarbonate-macrolide copolyol to the polycaprolactone-lactide copolyol is (30-55):(5-20).

[0014] Furthermore, the number average molecular weight of the polycarbonate-macrolide copolyol is 2000-8000 g / mol.

[0015] Furthermore, the number average molecular weight of the polycaprolactone-lactide copolymer polyol is 2000-6000 g / mol.

[0016] Further, the diisocyanate is one or more of 4,4-dicyclohexylmethane diisocyanate (HMDI), toluene diisocyanate, isophorone diisocyanate, isophthalic diisocyanate, and 1,5-naphthalene diisocyanate.

[0017] Furthermore, the chain extender comprises chain extender one and chain extender two in a mass ratio of 2:3.

[0018] Further, the chain extender is N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, with the following structure: .

[0019] Furthermore, the chain extender II is 2-methyl-1,3-propanediol.

[0020] Furthermore, the anti-hydrolysis agent is one or more of carbodiimide, phenyl glycidyl ether, bisphenol A diglycidyl ether, and 1,2,3-propanetriol dehydroglycerol ether.

[0021] Furthermore, the nucleating agent is a mixture of sorbitol nucleating agent and phosphate salt nucleating agent in a mass ratio of 1:1.

[0022] Furthermore, the sorbitol nucleating agent is 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol.

[0023] Furthermore, the phosphate ester nucleating agent is 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum.

[0024] Furthermore, the antioxidant is a combination of a primary antioxidant and a secondary antioxidant in a 1:2 ratio.

[0025] Furthermore, the primary antioxidant includes one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), and 2,6-di-tert-butyl-p-cresol (antioxidant 264).

[0026] Furthermore, the co-antioxidant includes one or more of the following: tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), pentaerythritol diphosphite (antioxidant 626), dioctadecyl thiodipropionate (antioxidant DSTP), and pentaerythritol diphosphate (antioxidant 636).

[0027] Furthermore, the catalyst is stannous octoate.

[0028] This embodiment also provides a method for preparing the thermoplastic polyurethane elastomer, including the following steps: Step 1: Heat the diisocyanate for later use; Step 2: Mix the biomass polyol, anti-hydrolysis agent, nucleating agent and antioxidant to obtain a premix; Step 3: Stir and mix chain extender one and chain extender two to obtain a premixed chain extender, and keep it warm for later use; Step 4: Add the diisocyanate, the premix, and the premixed chain extender from Step 1 into a twin-screw extruder for melt blending to obtain the thermoplastic polyurethane elastomer.

[0029] Furthermore, the heating temperature in step 1 is 40-50℃.

[0030] Further, the diisocyanate in step 1 is one or more of 4,4-dicyclohexylmethane diisocyanate (HMDI), toluene diisocyanate, isophorone diisocyanate, isophthalic diisocyanate, and 1,5-naphthalene diisocyanate.

[0031] Furthermore, in step 2, the stirring speed is 2000-3000 rpm, the stirring time is 200-300 min, and the stirring temperature is 70-80℃.

[0032] Furthermore, the bio-based polyol in step 2 is a polycarbonate-macrolide copolymer polyol and a polycaprolactone-lactide copolymer polyol.

[0033] Furthermore, the mass ratio of the polycarbonate-macrolide copolyol to the polycaprolactone-lactide copolyol is (30-55):(5-20).

[0034] Furthermore, the number average molecular weight of the polycarbonate-macrolide copolyol is 2000-8000 g / mol.

[0035] Furthermore, the number average molecular weight of the polycaprolactone-lactide copolymer polyol is 2000-6000 g / mol.

[0036] Further, the anti-hydrolysis agent in step 2 is one or more of carbodiimide, phenyl glycidyl ether, bisphenol A diglycidyl ether, and 1,2,3-propanetriol dehydrated glyceryl ether.

[0037] Furthermore, the nucleating agent in step 2 is a mixture of sorbitol nucleating agent and phosphate salt nucleating agent in a mass ratio of 1:1.

[0038] Furthermore, the sorbitol nucleating agent is 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol.

[0039] Furthermore, the phosphate ester nucleating agent is 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum.

[0040] Furthermore, in step 2, the antioxidant is a combination of the main antioxidant and the auxiliary antioxidant in a 1:2 ratio.

[0041] Furthermore, the primary antioxidant includes one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), and 2,6-di-tert-butyl-p-cresol (antioxidant 264).

[0042] Furthermore, the co-antioxidant includes one or more of the following: tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), pentaerythritol diphosphite (antioxidant 626), dioctadecyl thiodipropionate (antioxidant DSTP), and pentaerythritol diphosphate (antioxidant 636).

[0043] Furthermore, the catalyst in step 2 is stannous octoate.

[0044] Furthermore, in step 3, the stirring speed is 300-400 rpm, and the stirring time is 20-30 min.

[0045] Furthermore, the temperature for heat preservation in step 3 is 50-60℃.

[0046] Furthermore, the chain extender in step 3 includes chain extender one and chain extender two in a mass ratio of 2:3.

[0047] Furthermore, the chain extender is N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester.

[0048] Furthermore, the chain extender II is 2-methyl-1,3-propanediol.

[0049] Furthermore, in step 4, the extrusion temperature of the twin-screw extruder is 140-180℃, divided into 14 temperature zones, wherein the temperature of the first temperature zone is 140-150℃, the temperature of the second temperature zone is 140-150℃, the temperature of the third temperature zone is 150-160℃, the temperature of the fourth temperature zone is 150-160℃, the temperature of the fifth temperature zone is 160-170℃, the temperature of the sixth temperature zone is 160-170℃, the temperature of the seventh temperature zone is 170-180℃, the temperature of the eighth temperature zone is 170-180℃, the temperature of the ninth temperature zone is 170-180℃, the temperature of the tenth temperature zone is 170-180℃, the temperature of the eleventh temperature zone is 160-170℃, the temperature of the twelfth temperature zone is 160-170℃, the temperature of the thirteenth temperature zone is 160-170℃, and the temperature of the fourteenth temperature zone is 150-160℃.

[0050] Furthermore, in step 4, the screw speed of the twin-screw extruder is 180-220 rpm.

[0051] Furthermore, in step 4, the drying temperature of the homogenization chamber in the twin-screw extruder is 50-70℃, and the drying time is 6-10h.

[0052] The present invention also provides a film prepared from the thermoplastic polyurethane elastomer.

[0053] Furthermore, the thermoplastic polyurethane elastomer is also used in sportswear, electronic products, medical devices, and environmentally friendly packaging.

[0054] The beneficial effects of this invention are: In this invention, two specific bio-based polyols are blended. Among the two bio-based polyols, the polycarbonate-macrolide copolyol has better degradability than the polycaprolactone-lactide copolyol. After mixing using the ratio specified in this invention, a high degradation rate can be maintained while ensuring the light transmittance of the material. The specific bio-based polyol undergoes a nucleophilic addition reaction with diisocyanate, and a mixed composite chain extender is used to regulate the microphase structure of the material. This allows the resulting thermoplastic polyurethane elastomer to maintain high resilience while possessing high light transmittance and low turbidity. The composite chain extender in this invention introduces flame-retardant components into the polyurethane molecular chain through chemical bonds, eliminating the need for additional flame retardants. Furthermore, the specific ratio of the composite chain extender reduces the migration rate of the chain extender within the material, improving its stability and durability during long-term use. In addition, the material exhibits excellent mechanical properties after the components are mixed and reacted, while also possessing degradability and hydrolysis resistance. The material preparation method has a clear and highly controllable process flow, does not involve high solvent consumption or complex recovery steps, and is suitable for continuous industrial production, demonstrating promising application prospects. Detailed Implementation

[0055] The invention will be described in detail below with reference to the embodiments: This invention provides a thermoplastic polyurethane elastomer, its preparation method, and its application. Through the specific nucleophilic addition reaction of polyol and isocyanate in this invention, followed by the mixing and compounding of chain extenders, the reaction process of polyol and isocyanate is ensured. At the same time, the selection of composite chain extenders also endows the material with flame retardant properties and reduces the migration rate of chain extenders. Further mixing of other additives improves the light transmittance of the material without reducing its resilience and mechanical properties.

[0056] Example 1 This embodiment provides a thermoplastic polyurethane elastomer with the following characteristics: 1.5 mm thickness, light transmittance of 96%, turbidity of 1.5%, resilience of 99.4%, and flame retardancy rating of V1; weight retention of 48% after 60 days; 300% tensile stress of 11 MPa, tensile strength of 44 MPa, and tear strength of 155 kN / m; hydrolysis resistance of 84% after boiling in water at 70°C for 7 days; and migration rate of the chain extender in the thermoplastic polyurethane elastomer of 0.97%.

[0057] The components and contents of the thermoplastic polyurethane elastomer described in this embodiment are as follows: Bio-based polyols: 60 parts by weight, specifically 55 parts by weight of polycarbonate-macrolide copolyol with a number average molecular weight of 2000 and 5 parts by weight of polycaprolactone-lactide copolyol with a number average molecular weight of 2000. Diisocyanate: 27 parts by weight, specifically 4,4-dicyclohexylmethane diisocyanate (HMDI). Chain extender: 10 parts by weight, wherein chain extender one is 4 parts by weight, specifically N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, and chain extender two is 6 parts by weight, specifically 2-methyl-1,3-propanediol; Anti-hydrolysis agent: 0.3 parts by weight, specifically carbodiimide; Nucleating agent: 2 parts by weight, specifically 1 part by weight of 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol (NA-98) and 1 part by weight of 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum (NAP-62). Antioxidant: 0.7 parts by weight, specifically pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:2; Catalyst: 0.03 parts by weight, specifically stannous octoate.

[0058] This embodiment also provides a method for preparing the thermoplastic polyurethane elastomer, including the following steps: Step 1: Heat the diisocyanate to 45°C for later use; Step 2: Mix biomass polyol, anti-hydrolysis agent, nucleating agent and antioxidant at 80℃ and 2400rpm for 240min to obtain premix; Step 3: Mix chain extender one and chain extender two at 350 rpm for 30 min to obtain a premixed chain extender, and keep it at 60℃ for later use. Step 4: The diisocyanate, the premix, and the premixed chain extender from Step 1 are added together to a twin-screw extruder for melt blending, extruded, pelletized, and dried to obtain the thermoplastic polyurethane elastomer; The twin-screw extruder has an extrusion temperature of 140-180℃, divided into 14 temperature zones: zone 1 is 140℃, zone 2 is 145℃, zone 3 is 150℃, zone 4 is 155℃, zone 5 is 160℃, zone 6 is 165℃, zone 7 is 170℃, zone 8 is 175℃, zone 9 is 180℃, zone 10 is 180℃, zone 11 is 175℃, zone 12 is 170℃, zone 13 is 165℃, and zone 14 is 160℃. The twin-screw extruder has a screw speed of 180 rpm, a homogenization chamber drying temperature of 50°C, and a drying time of 10 hours.

[0059] Example 2 This embodiment provides a thermoplastic polyurethane elastomer with the following characteristics: 1.5 mm thickness, light transmittance of 97%, turbidity of 1.3%, resilience of 99.8%, and flame retardancy rating of V1; weight retention of 51% after 60 days; 300% tensile stress of 13 MPa, tensile strength of 49 MPa, and tear strength of 151 kN / m; hydrolysis resistance of 81% after boiling in water at 70°C for 7 days; and migration rate of the chain extender in the thermoplastic polyurethane elastomer of 0.95%.

[0060] The components and contents of the thermoplastic polyurethane elastomer described in this embodiment are as follows: Bio-based polyols: 60 parts by weight, specifically 55 parts by weight of polycarbonate-macrolide copolyol with a number average molecular weight of 2000 and 5 parts by weight of polycaprolactone-lactide copolyol with a number average molecular weight of 2000. Diisocyanate: 27 parts by weight, specifically 4,4-dicyclohexylmethane diisocyanate (HMDI). Chain extender: 10 parts by weight, wherein chain extender one is 4 parts by weight, specifically N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, and chain extender two is 6 parts by weight, specifically 2-methyl-1,3-propanediol; Anti-hydrolysis agent: 0.3 parts by weight, specifically carbodiimide; Nucleating agent: 2 parts by weight, specifically 1 part by weight of 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol (NA-98) and 1 part by weight of 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum (NAP-62). Antioxidant: 0.7 parts by weight, specifically pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:2; Catalyst: 0.03 parts by weight, specifically stannous octoate.

[0061] This embodiment also provides a method for preparing the thermoplastic polyurethane elastomer, including the following steps: Step 1: Heat the diisocyanate to 45°C for later use; Step 2: Mix biomass polyol, anti-hydrolysis agent, nucleating agent and antioxidant at 80℃ and 2400rpm for 240min to obtain premix; Step 3: Mix chain extender one and chain extender two at 350 rpm for 30 min to obtain a premixed chain extender, and keep it at 60℃ for later use. Step 4: The diisocyanate, the premix, and the premixed chain extender from Step 1 are added together to a twin-screw extruder for melt blending, extruded, pelletized, and dried to obtain the thermoplastic polyurethane elastomer; The twin-screw extruder has an extrusion temperature of 140-180℃, divided into 14 temperature zones: zone 1 is 140℃, zone 2 is 145℃, zone 3 is 150℃, zone 4 is 155℃, zone 5 is 160℃, zone 6 is 165℃, zone 7 is 170℃, zone 8 is 175℃, zone 9 is 180℃, zone 10 is 180℃, zone 11 is 175℃, zone 12 is 170℃, zone 13 is 165℃, and zone 14 is 160℃. The twin-screw extruder has a screw speed of 200 rpm, a homogenization chamber drying temperature of 70°C, and a drying time of 8 hours.

[0062] Example 3 This embodiment provides a thermoplastic polyurethane elastomer with the following characteristics: 1.5 mm thickness, light transmittance of 94%, turbidity of 1.7%, resilience of 98.4%, and flame retardancy rating of V1; weight retention of 53% after 60 days; 300% tensile stress of 11 MPa, tensile strength of 44 MPa, and tear strength of 148 kN / m; hydrolysis resistance of 84% after boiling in water at 70°C for 7 days; and migration rate of the chain extender in the thermoplastic polyurethane elastomer of 0.95%.

[0063] The components and contents of the thermoplastic polyurethane elastomer described in this embodiment are as follows: Bio-based polyols: 60 parts by weight, specifically 50 parts by weight of polycarbonate-macrolide copolyol with a number average molecular weight of 2000 and 10 parts by weight of polycaprolactone-lactide copolyol with a number average molecular weight of 2000. Diisocyanate: 27 parts by weight, specifically 4,4-dicyclohexylmethane diisocyanate (HMDI). Chain extender: 10 parts by weight, wherein chain extender one is 4 parts by weight, specifically N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, and chain extender two is 6 parts by weight, specifically 2-methyl-1,3-propanediol; Anti-hydrolysis agent: 0.3 parts by weight, specifically carbodiimide; Nucleating agent: 2 parts by weight, specifically 1 part by weight of 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol (NA-98) and 1 part by weight of 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum (NAP-62). Antioxidant: 0.7 parts by weight, specifically pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:2; Catalyst: 0.03 parts by weight, specifically stannous octoate.

[0064] This embodiment also provides a method for preparing the thermoplastic polyurethane elastomer, including the following steps: Step 1: Heat the diisocyanate to 45°C for later use; Step 2: Mix biomass polyol, anti-hydrolysis agent, nucleating agent and antioxidant at 80℃ and 2400rpm for 240min to obtain premix; Step 3: Mix chain extender one and chain extender two at 350 rpm for 30 min to obtain a premixed chain extender, and keep it at 60℃ for later use. Step 4: The diisocyanate, the premix, and the premixed chain extender from Step 1 are added together to a twin-screw extruder for melt blending, extruded, pelletized, and dried to obtain the thermoplastic polyurethane elastomer; The twin-screw extruder has an extrusion temperature of 140-180℃, divided into 14 temperature zones: zone 1 is 140℃, zone 2 is 145℃, zone 3 is 150℃, zone 4 is 155℃, zone 5 is 160℃, zone 6 is 165℃, zone 7 is 170℃, zone 8 is 175℃, zone 9 is 180℃, zone 10 is 180℃, zone 11 is 175℃, zone 12 is 170℃, zone 13 is 165℃, and zone 14 is 160℃. The twin-screw extruder has a screw speed of 220 rpm, a drying temperature of 70°C in the homogenization chamber, and a drying time of 10 hours.

[0065] Comparative Example 1 This comparative example provides a thermoplastic polyurethane elastomer with the following characteristics: 1.5 mm light transmittance is 99%, turbidity is 1.2%, resilience is 99.7%, and flame retardancy is non-flame retardant; the weight retention rate of the thermoplastic polyurethane elastomer after 60 days is 47%; the 300% tensile stress of the thermoplastic polyurethane elastomer is 6 MPa, tensile strength is 27 MPa, and tear strength is 89 kN / m; the hydrolysis resistance rate of the thermoplastic polyurethane elastomer after boiling in water at 70°C for 7 days is 81%; and the migration rate of the chain extender in the thermoplastic polyurethane elastomer is 1.91%.

[0066] The components and contents of the thermoplastic polyurethane elastomer mentioned in this comparative example are as follows: Bio-based polyols: 60 parts by weight, specifically 55 parts by weight of polycarbonate-macrolide copolyol with a number average molecular weight of 2000 and 5 parts by weight of polycaprolactone-lactide copolyol with a number average molecular weight of 2000. Diisocyanate: 27 parts by weight, specifically 4,4-dicyclohexylmethane diisocyanate (HMDI). Chain extender 2: 6 parts by weight, specifically 2-methyl-1,3-propanediol; Anti-hydrolysis agent: 0.3 parts by weight, specifically carbodiimide; Nucleating agent: 2 parts by weight, specifically 1 part by weight of 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol (NA-98) and 1 part by weight of 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum (NAP-62). Antioxidant: 0.7 parts by weight, specifically pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:2; Catalyst: 0.03 parts by weight, specifically stannous octoate.

[0067] This comparative example also provides a method for preparing the thermoplastic polyurethane elastomer, comprising the following steps: Step 1: Heat the diisocyanate to 45°C for later use; Step 2: Mix biomass polyol, anti-hydrolysis agent, nucleating agent and antioxidant at 80℃ and 2400rpm for 240min to obtain premix; Step 3: Stir chain extender 2 at 350 rpm for 30 min to obtain premixed chain extender, and keep it at 60℃ for later use; Step 4: The diisocyanate, the premix, and the premixed chain extender from Step 1 are added together to a twin-screw extruder for melt blending, extruded, pelletized, and dried to obtain the thermoplastic polyurethane elastomer; The twin-screw extruder has an extrusion temperature of 140-180℃, divided into 14 temperature zones: zone 1 is 140℃, zone 2 is 145℃, zone 3 is 150℃, zone 4 is 155℃, zone 5 is 160℃, zone 6 is 165℃, zone 7 is 170℃, zone 8 is 175℃, zone 9 is 180℃, zone 10 is 180℃, zone 11 is 175℃, zone 12 is 170℃, zone 13 is 165℃, and zone 14 is 160℃. The twin-screw extruder has a screw speed of 180 rpm, a homogenization chamber drying temperature of 50°C, and a drying time of 10 hours.

[0068] Comparative Example 2 This comparative example provides a thermoplastic polyurethane elastomer with the following characteristics: 1.5 mm light transmittance is 89%, turbidity is 3.1%, resilience is 94.1%, and flame retardancy rating is V1; the weight retention rate of the thermoplastic polyurethane elastomer after 60 days is 47%; the 300% tensile stress of the thermoplastic polyurethane elastomer is 6 MPa, tensile strength is 31 MPa, and tear strength is 77 kN / m; the hydrolysis resistance rate of the thermoplastic polyurethane elastomer after boiling in water at 70°C for 7 days is 81%; and the migration rate of the chain extender in the thermoplastic polyurethane elastomer is 2.80%.

[0069] The components and contents of the thermoplastic polyurethane elastomer mentioned in this comparative example are as follows: Bio-based polyols: 60 parts by weight, specifically 55 parts by weight of polycarbonate-macrolide copolyol with a number average molecular weight of 2000 and 5 parts by weight of polycaprolactone-lactide copolyol with a number average molecular weight of 2000. Diisocyanate: 27 parts by weight, specifically 4,4-dicyclohexylmethane diisocyanate (HMDI). Chain extender 1: 6 parts by weight, specifically diethyl N,N-bis(2-hydroxyethyl)aminomethylenephosphonate; Anti-hydrolysis agent: 0.3 parts by weight, specifically carbodiimide; Nucleating agent: 2 parts by weight, specifically 1 part by weight of 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol (NA-98) and 1 part by weight of 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum (NAP-62). Antioxidant: 0.7 parts by weight, specifically pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:2; Catalyst: 0.03 parts by weight, specifically stannous octoate.

[0070] This comparative example also provides a method for preparing the thermoplastic polyurethane elastomer, comprising the following steps: Step 1: Heat the diisocyanate to 45°C for later use; Step 2: Mix biomass polyol, anti-hydrolysis agent, nucleating agent and antioxidant at 80℃ and 2400rpm for 240min to obtain premix; Step 3: Stir chain extender 1 at 350 rpm for 30 min to obtain premixed chain extender, and keep it at 60℃ for later use; Step 4: The diisocyanate, the premix, and the premixed chain extender from Step 1 are added together to a twin-screw extruder for melt blending, extruded, pelletized, and dried to obtain the thermoplastic polyurethane elastomer; The twin-screw extruder has an extrusion temperature of 140-180℃, divided into 14 temperature zones: zone 1 is 140℃, zone 2 is 145℃, zone 3 is 150℃, zone 4 is 155℃, zone 5 is 160℃, zone 6 is 165℃, zone 7 is 170℃, zone 8 is 175℃, zone 9 is 180℃, zone 10 is 180℃, zone 11 is 175℃, zone 12 is 170℃, zone 13 is 165℃, and zone 14 is 160℃. The twin-screw extruder has a screw speed of 180 rpm, a homogenization chamber drying temperature of 50°C, and a drying time of 10 hours.

[0071] Comparative Example 3 This comparative example provides a thermoplastic polyurethane elastomer with the following characteristics: 1.5 mm thickness, light transmittance of 94%, turbidity of 1.8%, resilience of 95.5%, and flame retardancy rating of non-flame retardant; weight retention of 47% after 60 days; 300% tensile stress of 13 MPa, tensile strength of 47 MPa, and tear strength of 169 kN / m; hydrolysis resistance of 81% after boiling in water at 70°C for 7 days; and migration rate of the chain extender in the thermoplastic polyurethane elastomer of 2.56%.

[0072] The components and contents of the thermoplastic polyurethane elastomer mentioned in this comparative example are as follows: Bio-based polyols: 60 parts by weight, specifically 55 parts by weight of polycarbonate-macrolide copolyol with a number average molecular weight of 2000 and 5 parts by weight of polycaprolactone-lactide copolyol with a number average molecular weight of 2000. Diisocyanate: 27 parts by weight, specifically 4,4-dicyclohexylmethane diisocyanate (HMDI). Chain extender: 6 parts by weight, specifically 1,4-butanediol; Anti-hydrolysis agent: 0.3 parts by weight, specifically carbodiimide; Nucleating agent: 2 parts by weight, specifically 1 part by weight of 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol (NA-98) and 1 part by weight of 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum (NAP-62). Antioxidant: 0.7 parts by weight, specifically pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:2; Catalyst: 0.03 parts by weight, specifically stannous octoate.

[0073] This comparative example also provides a method for preparing the thermoplastic polyurethane elastomer, comprising the following steps: Step 1: Heat the diisocyanate to 45°C for later use; Step 2: Mix biomass polyol, anti-hydrolysis agent, nucleating agent and antioxidant at 80℃ and 2400rpm for 240min to obtain premix; Step 3: Stir the chain extender at 350 rpm for 30 min to obtain a premixed chain extender, and keep it at 60℃ for later use. Step 4: The diisocyanate, the premix, and the premixed chain extender from Step 1 are added together to a twin-screw extruder for melt blending, extruded, pelletized, and dried to obtain the thermoplastic polyurethane elastomer; The twin-screw extruder has an extrusion temperature of 140-180℃, divided into 14 temperature zones: zone 1 is 140℃, zone 2 is 145℃, zone 3 is 150℃, zone 4 is 155℃, zone 5 is 160℃, zone 6 is 165℃, zone 7 is 170℃, zone 8 is 175℃, zone 9 is 180℃, zone 10 is 180℃, zone 11 is 175℃, zone 12 is 170℃, zone 13 is 165℃, and zone 14 is 160℃. The twin-screw extruder has a screw speed of 180 rpm, a homogenization chamber drying temperature of 50°C, and a drying time of 10 hours.

[0074] Comparative Example 4 This comparative example provides a thermoplastic polyurethane elastomer with the following characteristics: 1.5 mm light transmittance is 95%, turbidity is 1.3%, resilience is 99.4%, and flame retardancy rating is V1; the weight retention rate of the thermoplastic polyurethane elastomer after 60 days is 45%; the 300% tensile stress of the thermoplastic polyurethane elastomer is 13 MPa, tensile strength is 42 MPa, and tear strength is 149 kN / m; the hydrolysis resistance rate of the thermoplastic polyurethane elastomer after boiling in water at 70°C for 7 days is 82%; and the migration rate of the chain extender in the thermoplastic polyurethane elastomer is 1.71%.

[0075] The components and contents of the thermoplastic polyurethane elastomer mentioned in this comparative example are as follows: Bio-based polyols: 60 parts by weight, specifically 55 parts by weight of polycarbonate-macrolide copolyol with a number average molecular weight of 2000 and 5 parts by weight of polycaprolactone-lactide copolyol with a number average molecular weight of 2000. Diisocyanate: 27 parts by weight, specifically 4,4-dicyclohexylmethane diisocyanate (HMDI). Chain extender: 10 parts by weight, of which chain extender one is 7 parts by weight, specifically N,N-bis(2-hydroxyethyl)aminomethylenephosphonic acid diethyl ester, and chain extender two is 3 parts by weight, specifically 2-methyl-1,3-propanediol; Anti-hydrolysis agent: 0.3 parts by weight, specifically carbodiimide; Nucleating agent: 2 parts by weight, specifically 1 part by weight of 1,3:2,4-bis(3,4-dimethylbenzyl)-D-sorbitol (NA-98) and 1 part by weight of 2,2'-methylene-bis(4,6-di-tert-butylphenyl phosphate) basic aluminum (NAP-62). Antioxidant: 0.7 parts by weight, specifically pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:2; Catalyst: 0.03 parts by weight, specifically stannous octoate.

[0076] This comparative example also provides a method for preparing the thermoplastic polyurethane elastomer, comprising the following steps: Step 1: Heat the diisocyanate to 45°C for later use; Step 2: Mix biomass polyol, anti-hydrolysis agent, nucleating agent and antioxidant at 80℃ and 2400rpm for 240min to obtain premix; Step 3: Mix chain extender one and chain extender two at 350 rpm for 30 min to obtain a premixed chain extender, and keep it at 60℃ for later use. Step 4: The diisocyanate, the premix, and the premixed chain extender from Step 1 are added together to a twin-screw extruder for melt blending, extruded, pelletized, and dried to obtain the thermoplastic polyurethane elastomer; The twin-screw extruder has an extrusion temperature of 140-180℃, divided into 14 temperature zones: zone 1 is 140℃, zone 2 is 145℃, zone 3 is 150℃, zone 4 is 155℃, zone 5 is 160℃, zone 6 is 165℃, zone 7 is 170℃, zone 8 is 175℃, zone 9 is 180℃, zone 10 is 180℃, zone 11 is 175℃, zone 12 is 170℃, zone 13 is 165℃, and zone 14 is 160℃. The twin-screw extruder has a screw speed of 180 rpm, a homogenization chamber drying temperature of 50°C, and a drying time of 10 hours.

[0077] Table 1 shows the performance in this embodiment and the comparative example.

[0078] The thermoplastic polyurethane elastomer described in this invention is prepared by reacting a specific mixture of bio-based polyols with diisocyanate, with a composite chain extender and other additives added during the reaction process. The thermoplastic polyurethane elastomer of this invention has high light transmittance and low turbidity, improving light transmittance while maintaining high resilience. The addition of the composite chain extender improves the flame retardancy of the thermoplastic polyurethane elastomer without affecting the mechanical properties of the material, and the chain extender has low migration rate. In addition, the thermoplastic polyurethane elastomer has low degradation performance—low weight retention rate—and can be effectively degraded. At the same time, it also has high hydrolysis resistance, resulting in excellent overall performance.

[0079] In Comparative Examples 1-3, the use of only a single chain extender or other chain extenders resulted in the materials lacking flame retardant properties, as well as reduced light transmittance and resilience. In Comparative Example 4, the proportion of chain extenders was changed, with the increased proportion of diethyl N,N-bis(2-hydroxyethyl)aminomethylenephosphonate, which led to a significant increase in the migration rate of the chain extender.

[0080] The light transmittance test standard for the material in this invention is ASTM D1003; the turbidity test standard is ASTM D1003; the resilience test standard is ISO 4662; the flame retardancy test standard is UL94; the weight retention test standard is ISO 14855; the biological agent is PBS buffer at 37°C; the compressive strength, tensile strength, and tear strength test standards are ASTM D624; the hydrolysis resistance test standard is ISO 175; and the migration test standard is ISO 177. The thermoplastic polyurethane elastomer was tested by injection molding the materials from the examples and comparative examples into 1.5mm sheet materials at room temperature (170-200°C).

[0081] As can be seen from the above, the thermoplastic polyurethane elastomer of the present invention has a wide range of applications, low cost, and a very high market prospect.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any modifications or equivalent changes made based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A thermoplastic polyurethane elastomer, characterized in that, The thermoplastic polyurethane elastomer has a light transmittance of 94-99%, a turbidity of 1.0-1.7%, a resilience of 98-99.9%, and a flame retardancy rating of V1; the weight retention rate of the thermoplastic polyurethane elastomer after 60 days is 45-55%; the compressive strength at 300% elongation is 10-15 N, the tensile strength is 44-50 MPa, and the tear strength is 145-170 MPa; the hydrolysis resistance of the thermoplastic polyurethane elastomer is 80-85%; and the migration rate of the chain extender in the thermoplastic polyurethane elastomer is 0.90-0.97%.

2. The thermoplastic polyurethane elastomer according to claim 1, characterized in that, The thermoplastic polyurethane elastomer includes bio-based polyols, diisocyanates, chain extenders, anti-hydrolysis agents, nucleating agents, and antioxidants.

3. The thermoplastic polyurethane elastomer according to claim 2, characterized in that, The components and their contents of the thermoplastic polyurethane elastomer are as follows: Bio-based polyols: 40-75 parts by weight; Diisocyanate: 15-35 parts by weight; Chain extender: 5-15 parts by weight; Anti-hydrolysis agent: 0.1-0.5 parts by weight; Nucleating agent: 1-3 parts by weight; Antioxidant: 0.5-1 parts by weight; Catalyst: 0.01-0.05 parts by weight.

4. The thermoplastic polyurethane elastomer according to claim 2, characterized in that, The bio-based polyols are polycarbonate-macrolide copolymer polyols and polycaprolactone-lactide copolymer polyols.

5. The thermoplastic polyurethane elastomer according to claim 4, characterized in that, The mass ratio of the polycarbonate-macrolide copolyol to the polycaprolactone-lactide copolyol is (30-55):(5-20).

6. The thermoplastic polyurethane elastomer according to claim 2, characterized in that, The chain extender comprises chain extender one and chain extender two in a mass ratio of 2:

3.

7. The thermoplastic polyurethane elastomer according to claim 6, characterized in that, The chain extender is N,N-bis(2-hydroxyethyl)aminomethylenephosphonate diethyl ester, with the following structure: .

8. The thermoplastic polyurethane elastomer according to claim 6, characterized in that, The chain extender II is 2-methyl-1,3-propanediol.

9. A method for preparing the thermoplastic polyurethane elastomer according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Heat the diisocyanate for later use; Step 2: Mix the biomass polyol, anti-hydrolysis agent, nucleating agent and antioxidant to obtain a premix; Step 3: Stir and mix chain extender one and chain extender two to obtain a premixed chain extender, and keep it warm for later use; Step 4: Add the diisocyanate, the premix, and the premixed chain extender from Step 1 into a twin-screw extruder for melt blending to obtain the thermoplastic polyurethane elastomer.

10. A thin film, characterized in that, The film is prepared from the thermoplastic polyurethane elastomer according to any one of claims 1-8.

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