Sebacic acid-based polyamide elastomer as well as preparation method and application thereof

Abstract

The invention discloses a polyamide elastomer based on sebacic acid and a preparation method and application thereof, the polyamide elastomer based on sebacic acid comprises the following raw materials: sebacic acid, diamine and polyether, and sebacic acid is prepared by a biological method. Compared with an elastomer prepared from chemical sebacic acid, the polyamide elastomer prepared from the biological sebacic acid as the raw material has the advantages that the mechanical property is more excellent, the yellow index is lower, and the application scene of an elastomer product can be further widened.

Description

[0001] This application claims the priority of the prior application filed with the State Intellectual Property Office of China on July 25, 2023, with patent application number 202310916139.X and entitled “A polyamide elastomer based on sebacic acid, its preparation method and application”. Technical Field

[0002] The invention relates to the technical field of thermoplastic elastomer preparation, and specifically discloses a polyamide elastomer based on bio-based sebacic acid and a preparation method and application thereof. Background Art

[0003] Thermoplastic elastomers are marketed in the form of various resin compositions such as polyurethanes, polystyrenes, polyolefins, polyesters, and polyamides. Polyamide thermoplastic elastomer (TPAE) is a member of the thermoplastic elastomer family. Compared with the widely used thermoplastic polyurethane elastomer (TPU), thermoplastic polyolefin elastomer (TPO), styrene thermoplastic elastomer (SBC), thermoplastic polyvinyl chloride elastomer (TPVC), and thermoplastic polyether ester elastomer (TPEE), the preparation and application of TPAE started later. Polyamide elastomers are widely used in automobiles, sports equipment, medical appliances, seals, mechanical parts, etc. due to their high elasticity, low specific gravity, high elasticity, and good low temperature performance.

[0004] Polyamide thermoplastic elastomer (TPAE) is mainly a copolymer composed of a polyamide hard segment and a polyether or polyester soft segment. The polyamides used as hard segments mainly include PA6, PA66, PA11, PA12, etc. The hard segment mainly determines the density, hardness, melting point, tensile strength, resistance to various organic chemicals and other properties of the polyamide thermoplastic elastomer; the soft segment mainly includes polycaprolactone (PCL), polyester alcohol, polyethylene glycol (PEG), polypropylene oxide ether (PPG), polytetramethylene glycol (PTMEG), etc. The soft segment mainly determines the low temperature properties, hygroscopicity, antistatic property, dyeability and stability to certain chemicals of the polyamide thermoplastic elastomer.

[0005] However, the existing dibasic acids used as monomer raw materials for the hard segment of polyamide, such as sebacic acid, are currently mainly prepared by chemical methods using castor oil as raw material. The production cycle is long, the process flow is complicated, the diluent is easy to pollute the environment, the production cost is high, and the prepared sebacic acid has a high impurity content, which causes the elastomer product to turn yellow and further has a negative impact on its mechanical properties. Summary of the invention

[0006] In order to solve the problems of high preparation cost of existing polyamide elastomers, poor quality of polymerization monomer sources, easy yellowing of elastomers, and mechanical properties to be further improved, the present invention provides a polyamide elastomer based on bio-based sebacic acid and a preparation method and application thereof. By optimizing the preparation process, a polyamide elastomer with a low yellowness index and excellent mechanical properties is obtained.

[0007] The first aspect of the present invention provides a sebacic acid-based polyamide elastomer, which includes a plurality of structural units of general formula C and general formula D, wherein the structural units are connected by ester groups; the general formula C is formed by connecting a plurality of general formulas A and B by amide bonds;

[0008]

[0009] Wherein, x is an integer from 5 to 16; R 1 C 1 ~C 5 The yellowness index of the sebacic acid-based polyamide elastomer is ≤10, further ≤6.

[0010] In some embodiments, the relative viscosity of the sebacic acid-based polyamide elastomer is 1.5-3.

[0011] In some embodiments, the Shore hardness of the sebacic acid-based polyamide elastomer is 22D-80D, preferably 30D-65D.

[0012] In some embodiments, the elongation at break of the sebacic acid-based polyamide elastomer is greater than 300%, preferably 500-950%.

[0013] In some embodiments, the density of the sebacic acid-based polyamide elastomer is 1.01 to 1.05 g / cm 3 .

[0014] In some embodiments, the sebacic acid-based polyamide elastomer has a tensile strength of 30 to 60 MPa, preferably 40 to 50 MPa.

[0015] In some embodiments, the sebacic acid-based polyamide elastomer has a notched impact strength of NB (not broken).

[0016] In some embodiments, in the sebacic acid-based polyamide elastomer, the mass percentage of the general formula A is 7-35%; the mass percentage of the general formula B is 18-52%; and the mass percentage of the general formula D is 16-74%.

[0017] In some embodiments, the raw material of the sebacic acid-based polyamide elastomer includes sebacic acid, diamine, and polyether.

[0018] In a preferred embodiment of the present invention, the molar ratio of sebacic acid, diamine and polyether is 1: (0.65-0.97): (0.05-0.36); more preferably, it is 1: (0.68-0.9): (0.1-0.35).

[0019] In a specific embodiment of the present invention, the sebacic acid is prepared by a biological method. The biological method includes using bio-based raw materials to produce sebacic acid through a bioconversion method (such as fermentation, enzyme conversion); or using petroleum-based raw materials to produce sebacic acid through a bioconversion method. Alternatively, sebacic acid contains organic carbon from a renewable source that meets the ASTM D6866 standard. Specifically, for example, the monomer raw material sebacic acid of the present invention can be prepared by the method disclosed in CN107326051A.

[0020] In a preferred embodiment of the present invention, the purity of the sebacic acid is ≥99.5%, further ≥99.8%.

[0021] In a preferred embodiment of the present invention, the ash content of the sebacic acid is ≤30 ppm, further ≤20 ppm.

[0022] In a preferred embodiment of the present invention, the melting point of the sebacic acid is 131-135°C.

[0023] In some embodiments, the diamine is selected from aliphatic diamines having 5 to 16 carbon atoms, more preferably one or more of pentamethylenediamine, hexamethylenediamine and lauryldiamine.

[0024] In some embodiments, the polyether comprises C 2 -C 5 Polyoxyalkylene glycols, linear or branched C 2 -C 36 Alkylene, C 6 -C 20 One or a mixture of aromatic diols.

[0025] In a specific embodiment of the present invention, the polyether includes polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMEG) or a mixture thereof.

[0026] In one specific embodiment of the present invention, the number average molecular weight of the polyether is 400-5000, or 400-2000.

[0027] In the present invention, preferably, the number average molecular weight of the polypropylene glycol is 500-5000, for example, 1000, 2000, or 4000.

[0028] The second aspect of the present invention provides a method for preparing a polyamide elastomer based on sebacic acid, comprising the following steps:

[0029] S1, mixing bio-based sebacic acid, diamine, a first catalyst and water to prepare a polyamide salt solution, and adjusting the pH value of the polyamide salt solution to 4.5-6.8;

[0030] S2. The polyamide salt solution is heated to 200-250°C, the pressure is increased to 1.5-3.0 MPa, the water is discharged, the gas is exhausted and the pressure is reduced, and when the temperature is increased to 240-270°C, the vacuum is evacuated to -(0.01-0.08) MPa and maintained for 5-60 min; then the polyether and the second catalyst are added, and the reaction is stirred at a vacuum degree of -(0.01-0.1) MPa for 1-5 h, the pressure is restored to normal, the material is discharged and pelletized to obtain a polyamide elastomer based on sebacic acid.

[0031] In some embodiments, the concentration of the polyamide salt aqueous solution in step S1 is 30% to 70% (mass percentage).

[0032] In a preferred embodiment, in step S2, when the temperature drops below 100° C., polyether is added, and then the temperature is raised to 220-270° C., and the second catalyst is added.

[0033] In the present invention, the types and amounts of the sebacic acid, diamine and polyether are as described above and will not be repeated here.

[0034] In some embodiments, in step S1, the first catalyst is selected from one or more of phosphoric acid, phosphorous acid, trimethyl phosphite, triphenyl phosphite, trimethyl phosphate, triphenyl phosphate, sodium hypophosphite, zinc hypophosphite, calcium hypophosphite, and potassium hypophosphite, preferably sodium hypophosphite and / or calcium phosphate.

[0035] In some embodiments, in step S1, the amount of the first catalyst added is 0.001-5% of the total amount of the sebacic acid, the diamine and the first catalyst.

[0036] In some embodiments, in step S2, the second catalyst is one or more of a titanium-based catalyst, a zirconium-based catalyst, an antimony-based catalyst, and a germanium-based catalyst, more preferably a titanium-based catalyst.

[0037] In the present invention, the titanium catalyst is preferably one or more of tetrabutyl titanate, tetraethyl titanate and tetrapropyl titanate. The zirconium catalyst is preferably tetrabutyl zirconate and / or tetrapropyl zirconate. The antimony catalyst is preferably ethylene glycol antimony. The germanium catalyst is preferably GeO 2 .

[0038] In some embodiments, in step S2, the amount of the second catalyst added is 0.001 to 3% (mass percentage) of the total amount of the sebacic acid, the diamine, the polyether and the second catalyst.

[0039] In some specific embodiments, the method further comprises: adding an auxiliary agent to the polyamide salt aqueous solution in step S1, wherein the amount of the auxiliary agent added accounts for 0.01-2% of the total amount of the diamine, the sebacic acid and the auxiliary agent.

[0040] In the present invention, the auxiliary agent includes but is not limited to one or more of a lubricant, a nucleating agent, and an antioxidant.

[0041] Preferably, the lubricant includes one or more of aliphatic amide, aliphatic alcohol, aliphatic bisamide, and polyethylene wax.

[0042] Preferably, the nucleating agent includes one or more of silicon dioxide, talc, kaolin and clay.

[0043] Preferably, the antioxidant includes one or more of hindered phenol compounds, hydroquinone compounds, hydroquinone compounds, phosphite compounds and their substitutes, iodides, and copper salts, for example, antioxidant H10.

[0044] The present invention also provides a sebacic acid-based polyamide elastomer prepared by the above-mentioned preparation method.

[0045] The present invention also provides an application of the polyamide elastomer based on sebacic acid as described above in shoe soles, catheter materials, micro-transmission mechanical parts, shock-absorbing materials or damping sound insulation materials. Wherein, the shoe sole can be a sports shoe sole. Wherein, the catheter material can be a medical catheter material. Wherein, the shock-absorbing material can be a sports equipment shock-absorbing material.

[0046] The present invention also provides a plastic product, which is obtained by processing and molding the polyamide elastomer based on sebacic acid as described above, wherein the desired shape can be formed by injection molding, blow molding, film molding and other molding methods.

[0047] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention. The reagents and raw materials used in the present invention are all commercially available.

[0048] The positive and progressive effects of the present invention are: the polyamide elastomer obtained by using bio-based sebacic acid as raw material has better mechanical properties and lower yellow index than the elastomer prepared by using chemical-based sebacic acid as raw material, which can further broaden the application scenarios of elastomer products. In addition, the preparation method of the polyamide elastomer of the present invention is stable and controllable, with low energy consumption, and the source of bio-based sebacic acid monomer is stable. DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with preferred embodiments and comparative examples. It should be noted that the described embodiments are only representative embodiments and cannot represent all embodiments. The content described below is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0050] The sebacic acid used in the following examples and comparative examples is described as follows:

[0051] The commercial product of sebacic acid obtained by chemical method has the following characteristics: purity 99.58%, ash content 223ppm, melting point 132℃.

[0052] Bio-based sebacic acid A: purity 99.89%, ash content 13 ppm, melting point 135°C, provided by Cathay (Jinxiang) Biomaterials Co., Ltd.

[0053] Bio-process sebacic acid B: purity 99.86%, ash content 17ppm, melting point 135°C, provided by Cathay (Jinxiang) Biomaterials Co., Ltd.

[0054] Bio-process sebacic acid C: purity 99.58%, ash content 22ppm, melting point 132°C, provided by Cathay (Jinxiang) Biomaterials Co., Ltd.

[0055] Pentamethylenediamine: provided by Cathay (Jinxiang) Biomaterials Co., Ltd.

[0056] Hexamethylenediamine and lauryl diamine were purchased from Shanghai Titan Technology Co., Ltd.

[0057] In the following examples, PPG1000, PPG2000 and PPG4000 were purchased from Dow Chemical; the remaining raw materials can be obtained from commercial sources.

[0058] Example 1

[0059] S1. Under nitrogen conditions, add 776 g of pure water, 864.1 g of bio-sebacic acid A, 300 g of pentamethylenediamine, 0.58 g of sodium hypophosphite and 1.16 g of antioxidant H10 into a salt-forming kettle, mix and stir to prepare a polyamide salt solution with a concentration of 60%, and adjust the pH value of the polyamide salt solution to 5.13;

[0060] S2. Transfer the polyamide salt solution to a polymerization kettle, heat it to 220°C, raise the pressure in the kettle to 1.7MPa, discharge the water, exhaust the gas and reduce the pressure. When the temperature in the kettle rises to 250°C, evacuate to -0.06MPa and maintain for 0.5h. Then add 2996.9g PPG2000 and 8.32g tetrabutyl zirconate, stir and react for 5h at a vacuum degree of -0.1MPa, fill with nitrogen to normal pressure, discharge the material and cut into pellets to obtain a polyamide elastomer, the structural units and mass proportions thereof are shown below.

[0061]

[0062] Example 2

[0063] S1. Under nitrogen conditions, 1006 g of pure water, 1108.9 g of bio-sebacic acid A, 400 g of pentamethylenediamine, 0.76 g of sodium hypophosphite and 1.52 g of antioxidant H10 were added into a salt-forming kettle and mixed to obtain a polyamide salt solution with a concentration of 60%. The pH value of the polyamide salt solution was adjusted to 5.21.

[0064] S2. Transfer the polyamide salt solution to a polymerization kettle, heat it to 220°C, raise the pressure in the kettle to 1.7MPa, discharge the water, exhaust the gas and reduce the pressure. When the temperature in the kettle rises to 250°C, evacuate to -0.06MPa and maintain for 0.5h. Then add 1695.4g PPG1000 and 6.4g tetrabutyl zirconate, stir and react for 5h at a vacuum degree of -0.1MPa, fill with nitrogen to normal pressure, discharge the material and cut into pellets to obtain a polyamide elastomer, the structural units and mass proportions thereof are shown below.

[0065]

[0066]

[0067] Example 3

[0068] S1. Under nitrogen conditions, add 756 g of pure water, 735 g of bio-sebacic acid A, 400 g of hexamethylenediamine, 0.56 g of sodium hypophosphite and 1.12 g of antioxidant H10 into a salt-forming kettle, mix and stir to prepare a polyamide salt solution with a concentration of 60%, and adjust the pH value of the polyamide salt solution to 6.55;

[0069] S2. Transfer the polyamide salt solution to a polymerization kettle, heat it to 220°C, raise the pressure in the kettle to 1.7MPa, discharge the water, exhaust the gas and reduce the pressure. When the temperature in the kettle rises to 250°C, evacuate to -0.06MPa and maintain for 0.5h. Then add 207g PPG1000 and 5.23g tetrabutyl zirconate, stir and react for 5h at a vacuum degree of -0.1MPa, fill with nitrogen to normal pressure, discharge the material and cut into pellets to obtain a polyamide elastomer, the structural units and mass proportions thereof are shown below.

[0070]

[0071] Example 4

[0072] S1. Under nitrogen conditions, 965 g of pure water, 1047.6 g of bio-sebacic acid B, 400 g of pentamethylenediamine, 0.72 g of sodium hypophosphite and 1.45 g of antioxidant H10 were added into a salt-forming kettle and mixed to obtain a polyamide salt solution with a concentration of 60%. The pH value of the polyamide salt solution was adjusted to 5.34.

[0073] S2. Transfer the polyamide salt solution to a polymerization kettle, heat it to 220°C, raise the pressure in the kettle to 1.7MPa, discharge the water, exhaust the gas and reduce the pressure. When the temperature in the kettle rises to 250°C, evacuate to -0.06MPa and maintain for 0.5h. Then add 1367.2g PPG1000 and 8.43g tetrabutyl zirconate, stir and react for 5h at a vacuum degree of -0.1MPa, fill with nitrogen to normal pressure, discharge the material and cut into pellets to obtain a polyamide elastomer, the structural units and mass proportions of which are shown as follows.

[0074]

[0075] Example 5

[0076] S1. Under nitrogen conditions, 1146 g of pure water, 1219.2 g of bio-sebacic acid B, 500 g of pentamethylenediamine, 0.86 g of sodium hypophosphite and 1.72 g of antioxidant H10 were added into a salt-forming kettle, and the mixture was stirred to obtain a polyamide salt solution with a concentration of 60%. The pH value of the polyamide salt solution was adjusted to 5.57.

[0077] S2. Transfer the polyamide salt solution to a polymerization kettle, heat it to 220°C, raise the pressure in the kettle to 1.7MPa, discharge the water, exhaust the gas and reduce the pressure. When the temperature in the kettle rises to 250°C, evacuate to -0.06MPa and maintain for 0.5h. Then add 2318.4g PPG2000 and 4.03g tetrabutyl zirconate, stir and react for 5h at a vacuum degree of -0.1MPa, fill with nitrogen to normal pressure, discharge the material and cut into pellets to obtain a polyamide elastomer, the structural units and mass proportions thereof are shown below.

[0078]

[0079] Example 6

[0080] S1. Under nitrogen conditions, 1522.4 g of pure water, 822.4 g of bio-sebacic acid A, 700 g of lauryl diamine, 0.76 g of sodium hypophosphite and 1.52 g of antioxidant H10 were added to a salt-forming kettle and mixed to obtain a polyamide salt solution with a concentration of 60%. The pH value of the polyamide salt solution was adjusted to 5.91.

[0081] S2. Transfer the polyamide salt solution to a polymerization kettle, heat it to 220°C, raise the pressure in the kettle to 1.7MPa, discharge the water, exhaust the gas and reduce the pressure. When the temperature in the kettle rises to 250°C, evacuate to -0.06MPa and maintain for 0.5h. Then add 2163.3g PPG4000 and 7.1g tetrabutyl zirconate, stir and react for 5h at a vacuum degree of -0.1MPa, fill with nitrogen to normal pressure, discharge the material and cut into pellets to obtain a polyamide elastomer, the structural units and mass proportions thereof are shown below.

[0082]

[0083] Example 7

[0084] S1. Under nitrogen conditions, 1384 g of pure water, 1376.2 g of bio-sebacic acid B, 700 g of hexamethylenediamine, 1.04 g of sodium hypophosphite and 2.08 g of antioxidant H10 were added into a salt-forming kettle, and the mixture was stirred to obtain a polyamide salt solution with a concentration of 60%. The pH value of the polyamide salt solution was adjusted to 6.18.

[0085] S2. Transfer the polyamide salt solution to a polymerization kettle, heat it to 220°C, raise the pressure in the kettle to 1.7MPa, discharge the water, exhaust the gas and reduce the pressure. When the temperature in the kettle rises to 250°C, evacuate to -0.06MPa and maintain for 0.5h. Then add 1225.9g PPG2000 and 9.9g tetrabutyl zirconate, stir and react for 5h at a vacuum degree of -0.1MPa, fill with nitrogen to normal pressure, discharge the material and cut into pellets to obtain a polyamide elastomer, the structural units and mass proportions thereof are shown below.

[0086]

[0087] Example 8

[0088] S1. Under nitrogen conditions, 1494 g of pure water, 1541.8 g of bio-sebacic acid B, 700 g of pentamethylenediamine, 1.12 g of sodium hypophosphite and 2.24 g of antioxidant H10 were added into a salt-forming kettle, and the mixture was stirred to obtain a polyamide salt solution with a concentration of 60%. The pH value of the polyamide salt solution was adjusted to 6.37.

[0089] S2. Transfer the polyamide salt solution to a polymerization kettle, heat it to 220°C, raise the pressure in the kettle to 1.7MPa, discharge the water, exhaust the gas and reduce the pressure. When the temperature in the kettle rises to 250°C, evacuate to -0.06MPa and maintain for 0.5h. Then add 1440.4g PPG2000 and 7.36g tetrabutyl zirconate, stir and react for 5h at a vacuum degree of -0.1MPa, fill with nitrogen to normal pressure, discharge the material and cut into pellets to obtain a polyamide elastomer, the structural units and mass proportions thereof are shown below.

[0090]

[0091] Example 9

[0092] It is basically the same as Example 4, except that the added amount of bio-based sebacic acid B is 1047.6 g, the added amount of pentamethylenediamine is 400 g, and the added amount of PPG1000 is 1993.8 g.

[0093]

[0094] Example 10

[0095] The method is basically the same as Example 6, except that: in step S2, the polyamide salt solution is transferred to a polymerization kettle, heated to 220°C, the pressure in the kettle is increased to 1.7MPa, the water is discharged and the pressure is reduced, and when the temperature in the kettle rises to 250°C, the kettle is evacuated to -0.06MPa and maintained for 0.5h; when the temperature drops below 100°C, 2163.3g PPG4000 is added, the temperature is then increased to 250°C, 7.1g tetrabutyl zirconate is added, the reaction is stirred at a vacuum degree of -0.1MPa for 5h, nitrogen is filled to normal pressure, the material is discharged and pelletized to obtain a polyamide elastomer,

[0096] Embodiment 11

[0097] It is basically the same as Example 6, except that in step S1, bio-based sebacic acid A is replaced by bio-based sebacic acid C, and finally a polyamide elastomer is obtained.

[0098] Comparative Example 1

[0099] The method is basically the same as Example 5, except that in step S1, the bio-based sebacic acid B is replaced with a commercially available sebacic acid product obtained by a chemical method, and finally a polyamide elastomer is obtained.

[0100] Comparative Example 2

[0101] The method is basically the same as Example 3, except that in step S1, the bio-based sebacic acid A is replaced with a commercially available sebacic acid product obtained by a chemical method, and finally a polyamide elastomer is obtained.

[0102] Comparative Example 3

[0103] The method is basically the same as Example 6, except that in step S1, the bio-based sebacic acid A is replaced with a commercially available sebacic acid product obtained by a chemical method, and finally a polyamide elastomer is obtained.

[0104] Comparative Example 4

[0105] The method is basically the same as Example 1, except that, in step S2, the polyamide salt solution is transferred to a polymerization kettle, heated to 220°C, the pressure in the kettle is increased to 1.7MPa, the water is discharged, the gas is exhausted and the pressure is reduced, and when the temperature in the kettle rises to 250°C, the kettle is evacuated to -0.06MPa and maintained for 0.5h; then 2996.9g PPG2000 and 8.32g tetrabutyl zirconate are added, and the reaction is stirred for 5h under a vacuum degree of -0.09MPa, and then the absolute pressure is reduced to below 500Pa within 1h to place the reactants in a high vacuum, and the reaction is continued for 5h, nitrogen is filled to normal pressure, and the material is discharged and pelletized to obtain a polyamide elastomer.

[0106] The polyamide elastomers obtained in Examples 1 to 11 and Comparative Examples 1 to 4 were tested for performance according to the following test methods: 1) Density: refer to ISO 1183; 2) Relative viscosity: tested at 135° C. using an Ubbelohde viscometer with benzyl alcohol as the mobile phase; 3) Shore hardness: refer to ISO 7619; 4) Tensile strength / elongation at break: refer to ISO 527; 5) Notched impact strength: refer to ISO 180; 6) Yellowness index: refer to HG / T 3862-2006. The results are shown in Table 1.

[0107] Table 1

[0108]

[0109]

[0110] As shown in Table 1, the polyamide elastomer prepared by the bio-method sebacic acid in the present invention has better mechanical properties and lower yellow index than the polyamide elastomer prepared by the chemical method sebacic acid under the same preparation process, indicating that the polyamide elastomer prepared by the bio-method sebacic acid is much higher than the polyamide elastomer prepared by the chemical method sebacic acid in terms of both industrial value and environmental value. At the same time, bio-method sebacic acid and aliphatic diamines have been industrially produced and stably supplied, which solves the problem of high cost of polyamide elastomers, broadens the use scenarios of elastomers, and has high commercial value.

Claims

1. A polyamide elastomer based on sebacic acid, characterized in that It includes several structural units of general formula C and general formula D, and the structural units are connected by ester groups; the general formula C is formed by several general formulas A and B connected by amide bonds; General formula A; General formula B; General formula D; Wherein, x is an integer of 5 to 16; R1 is a C1 to C5 linear or branched alkylene group; and the yellowness index of the sebacic acid-based polyamide elastomer is ≤10, and further ≤6.

2. The sebacic acid-based polyamide elastomer according to claim 1, characterized in that The relative viscosity of the sebacic acid-based polyamide elastomer is 1.5 to 3; and / or, The Shore hardness of the sebacic acid-based polyamide elastomer is 22D to 80D, preferably 30D to 65D; and / or, The elongation at break of the sebacic acid-based polyamide elastomer is greater than 300%, preferably 500-950%; and / or, The density of the sebacic acid-based polyamide elastomer is 1.01 to 1.05 g / cm 3 and / or, The tensile strength of the sebacic acid-based polyamide elastomer is 30 to 60 MPa, preferably 40 to 50 MPa; and / or, The sebacic acid-based polyamide elastomer has a notched impact strength of NB (not broken).

3. The sebacic acid-based polyamide elastomer according to claim 1, characterized in that In the sebacic acid-based polyamide elastomer, the mass percentage of the general formula A is 7-35%; the mass percentage of the general formula B is 18-52%; and the mass percentage of the general formula D is 16-74%.

4. The sebacic acid-based polyamide elastomer according to claim 1, characterized in that The raw materials of the sebacic acid-based polyamide elastomer include sebacic acid, diamine and polyether; Preferably, the molar ratio of sebacic acid, diamine and polyether is 1:(0.65-0.97):(0.05-0.36), further 1:(0.68-0.9):(0.1-0.35); Preferably, the sebacic acid is prepared by biological method; Preferably, the purity of the sebacic acid is ≥99.5%, further ≥99.8%; and / or, the ash content of the sebacic acid is ≤30ppm, further ≤20ppm; and / or, the melting point of the sebacic acid is 131-135°C; Preferably, the diamine is selected from aliphatic diamines having 5 to 16 carbon atoms, more preferably one or more of pentamethylenediamine, hexamethylenediamine and lauryldiamine.

5. The sebacic acid-based polyamide elastomer according to claim 4, characterized in that The polyethers include C2-C5 polyoxyalkylene glycols, linear or branched C2-C 36 Alkylene, C6-C 20 One or a mixture of aromatic diols; Preferably, the polyether comprises polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMEG) or a mixture thereof; Preferably, the number average molecular weight of the polyether is 400-5000, or 400-2000.

6. A method for preparing a polyamide elastomer based on sebacic acid, characterized in that: The following steps are involved: S1, mixing bio-based sebacic acid, diamine, a first catalyst and water to prepare a polyamide salt solution, and adjusting the pH value of the polyamide salt solution to 4.5-6.8; S2. The polyamide salt solution is heated to 200-250°C, the pressure is increased to 1.5-3.0 MPa, the water is discharged, the gas is exhausted and the pressure is reduced, and when the temperature is increased to 240-270°C, the vacuum is evacuated to -(0.01-0.08) MPa and maintained for 5-60 min; then the polyether and the second catalyst are added, and the reaction is stirred at a vacuum degree of -(0.01-0.1) MPa for 1-5 h, the pressure is restored to normal, the material is discharged and pelletized to obtain a polyamide elastomer based on sebacic acid.

7. The method for preparing a polyamide elastomer based on sebacic acid according to claim 6, characterized in that: The molar ratio of the sebacic acid, the diamine and the polyether is 1:(0.65-0.97):(0.05-0.36), further 1:(0.68-0.9):(0.1-0.35); and / or, the purity of the sebacic acid is ≥99.5%, further ≥99.8%; and / or, the ash content of the sebacic acid is ≤30ppm, further ≤20ppm; and / or, the melting point of the sebacic acid is 131-135°C; And / or, the diamine is selected from aliphatic diamines having 5 to 16 carbon atoms, more preferably one or more of pentamethylenediamine, hexamethylenediamine and lauryldiamine; And / or, the polyether is selected from one or more of polyethylene glycol (PEG), polypropylene glycol (PPG), and polytetramethylene glycol (PTMEG); And / or, in step S2, when the temperature drops below 100° C., polyether is added, and then the temperature is raised to 220-270° C., and a second catalyst is added.

8. The method for preparing a polyamide elastomer based on sebacic acid according to claim 6, characterized in that: In step S1, the first catalyst is selected from one or more of phosphoric acid, phosphorous acid, trimethyl phosphite, triphenyl phosphite, trimethyl phosphate, triphenyl phosphate, sodium hypophosphite, zinc hypophosphite, calcium hypophosphite, and potassium hypophosphite, preferably sodium hypophosphite and / or calcium phosphate; and / or, the amount of the first catalyst added is 0.001 to 5% of the total amount of the sebacic acid, the diamine and the first catalyst; and / or, in step S2, the second catalyst is one or more of a titanium-based catalyst, a zirconium-based catalyst, an antimony-based catalyst and a germanium-based catalyst, more preferably a titanium-based catalyst; Further, the titanium catalyst is preferably one or more of tetrabutyl titanate, tetraethyl titanate and tetrapropyl titanate; the zirconium catalyst is preferably tetrabutyl zirconate and / or tetrapropyl zirconate; the antimony catalyst is preferably antimony ethylene glycol; the germanium catalyst is preferably GeO2; And / or, the amount of the second catalyst added is 0.001-3% of the total amount of the sebacic acid, the diamine, the polyether and the second catalyst.

9. Use of the sebacic acid-based polyamide elastomer according to any one of claims 1 to 5 in the fields of shoe soles, catheter materials, micro-transmission mechanical parts, shock-absorbing materials or damping sound insulation materials.

10. A plastic product obtained by processing and molding the sebacic acid-based polyamide elastomer according to any one of claims 1 to 5.

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