A high-resilience PA6-based polyamide thermoplastic elastomer, its preparation method and application

Abstract

This invention relates to a high-resilience PA6-based polyamide thermoplastic elastomer, its preparation method, and its applications. This invention overcomes the shortcomings of traditional PA6-based elastomers, such as low fracture strength and poor resilience due to insufficient intermolecular bonding. The elastomer of this invention is stable and controllable, exhibiting high fracture strength, excellent resilience, and adjustable Shore hardness, thus compensating for the deficiencies of existing technologies.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, and specifically relates to a high-resilience PA6-based polyamide thermoplastic elastomer, its preparation method, and its application. Background Technology

[0002] Thermoplastic elastomers (TPEs) are a class of polymeric materials that exhibit rubber-like elasticity at room temperature and can be plasticized and molded at high temperatures. Their macromolecular chains are mainly composed of plastic segments (hard segments) and rubber segments (soft segments). The hard segments possess strong intermolecular bonds, forming physical "cross-linking points" at room temperature, which determine the material's strength. The soft segments have a chain structure with strong free rotation capabilities, giving the material good elasticity. Furthermore, due to the thermal reversibility of the physical cross-linking network of the hard segments, TPEs exhibit good melt processability.

[0003] PA6-based polyamide thermoplastic elastomers are semi-crystalline block copolymers with PA6 as the hard segment and polyether as the soft segment. Their synthesis methods can generally be divided into two main categories: anionic ring-opening polymerization and hydrolytic ring-opening polymerization. Anionic ring-opening polymerization requires high purity raw materials and often uses the highly toxic activator phosgene, posing significant safety hazards during production. Furthermore, the product has poor performance, making it difficult to meet the application requirements of certain fields. Hydrolytic ring-opening polymerization, on the other hand, offers advantages such as superior product performance and a safe and controllable preparation process, and is currently the most widely used synthesis method in the industry.

[0004] Patent CN 101747510A describes the preparation of PA6 prepolymer by introducing diisocyanate during the hydrolytic ring-opening polymerization of caprolactam, followed by the synthesis of PA6-based polyamide thermoplastic elastomers through esterification and polycondensation reactions between the prepolymer and polyether soft segments. This method requires the addition of diisocyanate at high temperatures, and the production process is highly likely to cause harm to the human body.

[0005] Patent CN 106565953 A, based on caprolactam hydrolysis ring-opening technology, invented a novel synthesis method for PA6-based thermoplastic elastomers—a "three-step" synthesis method. This method uses caprolactam, dicarboxylic acid, diol, and polyether diol as raw materials, and prepares elastomers with excellent thermodynamic properties through processes such as the synthesis of carboxyl-terminated PA6 prepolymers, carboxyl-terminated esterification, and polyether diol copolymerization. However, due to the relatively weak intermolecular bonding forces, the macromolecular chains are prone to slippage during stretching, resulting in insufficient elastomer resilience and failing to meet the application requirements of specific fields.

[0006] Patent CN 107698771A discloses a PA6-based thermoplastic elastomer with a micro-crosslinked structure and its preparation method. This method involves introducing an appropriate amount of crosslinked structure into the elastomer to increase the intermolecular bonding force, thereby improving its resilience. However, due to limitations in the synthesis method, the location of crosslinking points in the elastomer prepared by this method cannot be controlled (distributed in the soft and hard phases), resulting in poor melt processability of the related products and limiting their application in certain specific fields.

[0007] In summary, PA6-based thermoplastic elastomers prepared by the above methods exhibit poor resilience due to the weak bonding force at the physical cross-linking points in the hard segments, leading to easy slippage of macromolecular chains during stretching. While elastomers prepared using traditional chemical cross-linking methods offer superior resilience, the random distribution of their chemical cross-linking points results in lower elongation at break and poor melt processability, limiting their further industrial applications. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a high-resilience PA6-based polyamide thermoplastic elastomer, its preparation method and application.

[0009] The present invention provides a thermoplastic elastomer, the thermoplastic elastomer comprising an elastomer body and a chemical framework connecting the elastomer body; wherein the elastomer body comprises hard segments and soft segments, and the chemical framework connecting the elastomer body is formed by a crosslinking reaction between a dicarboxylic acid and the hard segments.

[0010] The general formula for the hard segment is:

[0011] Wherein R includes CO(CH2)xNH and CO(CH2) x NHCONH, CO(CH2) x One of CO and CO(CH2)xCONH; m≥4, n≥1; x≥1; the soft segment is polydiol.

[0012] Furthermore, x ≥ 2.

[0013] Furthermore, R includes one of CO(CH2)5NH, CO(CH2)3NHCONH, CO(CH2)3CO, CO(CH2)2CO, and CO(CH2)3CONH; m≥4, n≥1.

[0014] The soft segment polyethylene glycol has a molecular weight range of 500–8000 g / mol and accounts for 10%–90% of the total elastomer.

[0015] in, The amino acid is derived from BOC protection, and further, the amino acid is an L-amino acid.

[0016] Furthermore, the amino acid is selected from L-amino acids, including one of L-lysine, L-citrulline, L-glutamic acid, L-aspartic acid, and L-glutamine. L-lysine and L-glutamine are further preferred.

[0017] Furthermore, the structure of the thermoplastic elastomer is as follows: Figure 1 As shown:

[0018] in It represents a dicarboxylic acid that, through an amidation reaction with "de-BOC amino", becomes the chemical framework connecting the macromolecular chains of elastomers.

[0019] For hard segments, the general structural formula is:

[0020]

[0021] Where m≥4, n≥1.

[0022] in, Derived from BOC-protected amino acids. The amino acids are selected from L-amino acids, including one of L-lysine, L-citrulline, L-glutamic acid, L-aspartic acid, and L-glutamine. L-lysine and L-glutamine are preferred.

[0023] It is a soft-segment polyethylene glycol with a molecular weight ranging from 500 to 8000 g / mol, accounting for 10% to 90% of the total elastomer.

[0024] This invention provides a method for preparing a thermoplastic elastomer, comprising:

[0025] (1) Preparation of BOC-protected amino acids

[0026] Under ice bath conditions, amino acids, water, dioxane, and tert-butyl dicarbonate (Boc)2O were mixed, and then potassium carbonate aqueous solution was added. The reaction was continued until the solution became clear, then purified and dried to obtain N-BOC-amino acids.

[0027] (2) Synthesis of microbranched PA6 elastomers

[0028] Caprolactam, water, N-BOC-amino acid, and end-capping agent are mixed and reacted under protective gas conditions to obtain carboxyl-terminated PA6 prepolymer. Diol is added and reacted, followed by the addition of polydiol and catalyst to obtain PA6-based elastomer (i.e., microbranched PA6-based elastomer).

[0029] (3) DeBOC protection of branched amino groups in hard segments and solid-phase crosslinking of hard segments in PA6 elastomers

[0030] The PA6 elastomer and solvent from step (2) are mixed, hydrochloric acid is added and reacted, and then dicarboxylic acid is added to carry out a hard segment solid-phase crosslinking reaction to obtain a thermoplastic elastomer.

[0031] Preferably, in step (1), the amino acids are 0.5-5 parts by weight, water is 8-12 parts, dioxane is 18-27 parts, and tert-butyl dicarbonate (Boc)2O is 1-8 parts.

[0032] In step (1), the amount of potassium carbonate is 0.1-5 parts;

[0033] Preferably, the amino acid in step (1) is an L-amino acid; the L-amino acid includes at least one of L-lysine, L-citrulline, L-glutamic acid, L-aspartic acid, and L-glutamine.

[0034] Preferably, in step (1), the potassium carbonate aqueous solution is added dropwise, and the addition is completed in 8-15 minutes.

[0035] A potassium carbonate aqueous solution is slowly added dropwise through a constant pressure dropping funnel.

[0036] Preferably, the purification in step (1) includes: removing water and dioxane from the reaction system by vacuum distillation to obtain a white solid; dissolving the solid in water and washing it with ether; adjusting the pH of the solution to the isoelectric point of amino acids; extracting with ethyl acetate; combining the organic layers; drying with anhydrous sodium sulfate; filtering; and concentrating the filtrate.

[0037] Preferably, in step (2), by weight, there are 100-120 parts of caprolactam, 1-10 parts of water, 1-25 parts of N-BOC-amino acid, 1-60 parts of capping agent, 1-100 parts of diol, 20-200 parts of polydiol, and 0.1-10 parts of catalyst.

[0038] The capping agent in step (2) includes one or more of succinic acid, adipic acid, sebacic acid, dodecanoic acid, terephthalic acid, isophthalic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid.

[0039] Preferably, the diol in step (2) includes one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol;

[0040] Preferably, the polydiol in step (2) includes one or more of polyethylene glycol, polypropylene glycol, polytetrahydrofuran glycol, polycaprolactone glycol, and polycarbonate glycol; wherein the number average molecular weight of the polydiol is 500-8000 g / mol.

[0041] Preferably, the catalyst in step (2) is a transesterification catalyst; the transesterification catalyst includes one or more of tetrabutyl titanate, isopropyl titanate, zinc acetate, manganese acetate, antimony acetate, magnesium acetate, sodium acetate, and antimony trioxide.

[0042] Preferably, the protective gas in step (2) is nitrogen;

[0043] Preferably, in step (2), caprolactam, water, N-BOC-amino acid, and capping agent are mixed and reacted under protective gas conditions, wherein the reaction is carried out under pressure of 1-10 bar at 220-240°C for 1-5 hours.

[0044] Preferably, in step (2), a diol is added for reaction, wherein the reaction is carried out at 220-240°C, at a pressure of 2-6 bar, and at a stirring speed of 50-500 r / min for 1-3 hours;

[0045] Preferably, in step (2), a polydiol and a catalyst are added for reaction, wherein the reaction is carried out at 220-280°C, 20-200 Pa, and 50-500 r / min for 0.5-5 h.

[0046] The reaction vessel in step (2) is a high-pressure reactor.

[0047] In step (2), caprolactam, water, N-BOC-amino acid and end-capping agent are mixed and reacted under protective gas conditions to obtain carboxyl-terminated PA6 prepolymer. Diol is added to react, followed by the addition of polydiol and catalyst. The pressure is balanced to atmospheric pressure, and PA6-based elastomer is obtained by casting, drawing, and pelletizing.

[0048] Preferably, in step (3), by weight, 10 parts of PA6-based elastomer and 0.005-0.03 parts of dicarboxylic acid are used; the solvent is hexafluoroisopropanol.

[0049] Preferably, the dicarboxylic acid includes one or more of succinic acid, adipic acid, sebacic acid, terephthalic acid, and isophthalic acid.

[0050] Preferably, in step (3), after adding hydrochloric acid, the reaction is carried out at room temperature for 1-2 hours;

[0051] Preferably, in step (3), after adding dicarboxylic acid, the mixture is precipitated, filtered, dried, and then cross-linked; for example, after adding dicarboxylic acid, the mixture is dropped into ice-cold methanol under thorough stirring to precipitate, filter, and dry.

[0052] Preferably, the crosslinking reaction in step (3) is carried out at 120-160°C for 10-24 hours.

[0053] This invention provides an application of the aforementioned thermoplastic elastomer in the textile field.

[0054] In this invention, the thermoplastic elastomer is a block copolymer composed of alternating soft and hard segments. The soft segments can produce large deformation under relatively small stress, making the fibers easy to elongate, while the hard segments, which are difficult to deform, can serve as nodes when the soft segments are stretched and rebound. The combined effect of the soft and hard segments gives the elastomer high elasticity. The cross-linked network structure is directionally introduced into the hard segments of the elastomer, which enhances the intermolecular bonding force of the hard segments. Ultimately, the elastomer of this invention is stable and controllable, and has high breaking strength, excellent resilience, adjustable Shore hardness, and good melt processability, thus overcoming the shortcomings of the prior art.

[0055] This invention provides a high-resilience PA6-based polyamide thermoplastic elastomer. The method involves preparing a bi-terminated carboxyl PA6 prepolymer by introducing BOC-protected amino acids during the hydrolysis and ring-opening process of caprolactam. Subsequently, a microbranched PA6 elastomer is prepared through esterification between the prepolymer and a diol, and transesterification of the related products with a polyethylene glycol. Finally, a hard-segment micro-crosslinked PA6 elastomer is prepared through an amidation reaction (solid-phase crosslinking process) between the prepolymer and a dicarboxylic acid after BOC removal. The high-resilience PA6-based polyamide thermoplastic elastomer is a polyether amide ester polymer resin with a micro-crosslinked structure in its hard segments, exhibiting high tensile strength and excellent resilience.

[0056] This invention mainly includes steps such as the preparation of BOC-protected amino acids, the synthesis of microbranched PA6-based elastomers, the removal of BOC protection from the hard-segment "branched amino groups," and solid-phase crosslinking. Based on the soft and hard-segment block copolymers of the elastomers of this invention and the directional introduction of a crosslinked network structure into the hard segments of the elastomers, the defects of traditional PA6-based elastomers, such as low tensile strength and poor resilience, caused by insufficient intermolecular bonding, are solved. Furthermore, the elastomers prepared using this method are stable and controllable, and exhibit high tensile strength, excellent resilience (elastic recovery rate exceeding 95% at 100% elongation), and adjustable Shore hardness, thus overcoming the shortcomings of existing technologies.

[0057] Beneficial effects

[0058] This invention, based on the hydrolysis and ring-opening process of PA6-based thermoplastic elastomers and combined with the theories of polymer chain branching and solid-phase crosslinking, develops a complete set of preparation technologies for high-elasticity PA6-based thermoplastic elastomers. This technology offers advantages such as mild reaction conditions and stable processes, overcoming the shortcomings of existing technologies. Furthermore, the elastomers prepared using this technology possess advantages such as high tensile strength, excellent resilience (elastic recovery rate ≥95% at 100% elongation), good melt processability, and adjustable Shore hardness, thus better meeting the processing and application requirements of specific fields. Attached Figure Description

[0059] Figure 1This is a schematic diagram of the structure of high-resilience PA6 thermoplastic elastomer. Detailed Implementation

[0060] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0061] In this invention, the molecular weight of the polyethylene glycol refers to the number-average molecular weight, expressed in g / mol. All raw materials used in this invention are commercially available products.

[0062] In this invention, the number-average molecular weight (M) of the sample was determined using Agilent 1260 Infinity II gel permeation chromatography (GPC). n The elution buffer was HFIP solution with a concentration of 1 mg / mL sodium trifluoroacetate (flow rate 0.3 mL / min). GPC curves were calibrated using polymethyl methacrylate (PMMA).

[0063] In this invention, a melt indexer is used to measure the melt index of the sample under a preload of 2160g at 240℃ to obtain the corresponding melt index.

[0064] In this invention, a WDW 3020 electric universal testing machine (Sansi, China) was used to conduct tensile and cyclic tensile tests on the elastomer at room temperature. Dumbbell-shaped specimens with a thickness of 2 mm and a width of 4 mm were prepared using a hot-pressing method. Each operation was repeated 5 times, and the average value was calculated. All samples were tested at a crosshead speed of 10 mm / min.

[0065] The hardness (H) of the elastomer in this invention was measured by Shore Durometer LX-A and LX-D (Handan, China).

[0066] Example 1

[0067] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0068] A. Preparation of BOC-protected amino acids

[0069] Under ice bath conditions, 0.66 g of L-lysine, 10 mL of water, 25 mL of dioxane, and 1.41 g of tert-butyl dicarbonate ((Boc)₂O) were added to a 100 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of the amino acid, and the solution was extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-lysine.

[0070] B. Synthesis of Microbranched PA6-based Elastomers

[0071] 113g caprolactam, 1.13g distilled water, 1.13g N-BOC-lysine, and 6g adipic acid were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 1 bar, and the reaction was continued at 220℃ for 5 hours to obtain a carboxyl-terminated PA6 prepolymer.

[0072] After the above reaction is completed, 1.13g of ethylene glycol is added to the autoclave using a secondary feeding device, and the reaction continues for 1 hour at a temperature of 220℃, a pressure of 2 bar, and a stirring speed of 50 r / min.

[0073] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 22.6g of polyethylene glycol (M). n =8000 g / mol), 0.1 g tetrabutyl titanate, and continued to react for 0.5 h at 280 °C, 20 Pa, and 150 r / min. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomer.

[0074] C.PA6-based elastomer hard segment solid-phase crosslinking

[0075] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.005g of succinic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 120℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 14000g / mol, a melt index of 18.3g / 10min, a tensile strength of 29MPa, an elongation at break of 200%, a Shore hardness of 57D, and an elastic recovery rate of 95% at 100% elongation.

[0076] Example 2

[0077] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0078] A. Preparation of BOC-protected amino acids

[0079] Under ice bath conditions, 1.02 g of L-glutamic acid, 10 mL of water, 25 mL of dioxane, and 1.41 g of tert-butyl dicarbonate ((Boc)₂O) were added to a 100 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of the amino acid, and the solution was extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-glutamic acid.

[0080] B. Synthesis of Microbranched PA6-based Elastomers

[0081] 113g caprolactam, 11.3g distilled water, 11.3g N-BOC-glutamic acid, and 1.13g succinic acid were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 5 bar, and the reaction was continued at 240℃ for 1 hour to obtain carboxyl-terminated PA6 prepolymer.

[0082] After the above reaction is completed, 90.4g of propylene glycol is added to the autoclave using a secondary feeding device, and the reaction continues for 3 hours at a temperature of 240℃, a pressure of 6 bar, and a stirring speed of 500 r / min.

[0083] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 256g of polytetrahydrofuran diol (M). n=500 g / mol) and 0.5 g sodium acetate were reacted at 220℃, 200 Pa, and 200 r / min for 5 h. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomer.

[0084] C.PA6-based elastomer hard segment solid-phase crosslinking

[0085] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.03g of succinic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 160℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 15000g / mol, a melt index of 17.2g / 10min, a tensile strength of 42MPa, an elongation at break of 210%, a Shore hardness of 54D, and an elastic recovery rate of 94% at 100% elongation.

[0086] Example 3

[0087] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0088] A. Preparation of BOC-protected amino acids

[0089] Under ice bath conditions, 0.73 g of L-citrulline, 10 mL of water, 25 mL of dioxane, and 1.41 g of tert-butyl dicarbonate ((Boc)₂O) were added to a 100 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of the amino acids. After extraction with ethyl acetate, the organic layers were combined, dried over anhydrous sodium sulfate, and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-citrulline.

[0090] B. Synthesis of Microbranched PA6-based Elastomers

[0091] 113g caprolactam, 5g distilled water, 19g sebacic acid, and 22.6g N-BOC-citrulline were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 10 bar, and the reaction was continued at 240℃ for 3 hours to obtain carboxyl-terminated PA6 prepolymer.

[0092] After the above reaction is completed, 90.4g of butanediol is added to the autoclave using a secondary feeding device, and the reaction continues for 3 hours at a temperature of 240℃, a pressure of 2.8 bar, and a stirring speed of 300 r / min.

[0093] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 100g of polytetrahydrofuran diol (M). n =3000 g / mol), 1.13 g of antimony trioxide, and reacted for 2 h at 220 °C, 75 Pa, and 500 r / min. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomers.

[0094] C.PA6-based elastomer hard segment solid-phase crosslinking

[0095] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.01g of sebacic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 150℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 17000g / mol, a melt index of 13.3g / 10min, a tensile strength of 26MPa, an elongation at break of 350%, a Shore hardness of 50D, and an elastic recovery rate of 96% at 100% elongation.

[0096] Example 4

[0097] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0098] A. Preparation of BOC-protected amino acids

[0099] Under ice bath conditions, 0.87 g of L-asparagine, 10 mL of water, 25 mL of dioxane, and 1.41 g of tert-butyl dicarbonate ((Boc)₂O) were added to a 100 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of the amino acid, and the solution was extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-asparagine.

[0100] B. Synthesis of Microbranched PA6-based Elastomers

[0101] 113g caprolactam, 4g distilled water, 20g dodecanoic acid, and 2.26g N-BOC-aspartic acid were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 10 bar, and the reaction was continued at 260℃ for 4 hours to obtain a carboxyl-terminated PA6 prepolymer.

[0102] After the above reaction is completed, 24g of pentanediol is added to the autoclave using a secondary feeding device, and the reaction continues for 2 hours at a temperature of 240℃, a pressure of 2 bar, and a stirring speed of 200 r / min.

[0103] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 100g of polyethylene glycol (M). n =4000 g / mol) and 0.3 g of antimony acetate were reacted at 250 °C, 50 Pa, and 50 r / min for 2 h. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomers.

[0104] C.PA6-based elastomer hard segment solid-phase crosslinking

[0105] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.01g of terephthalic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 120℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 16000g / mol, a melt index of 14.3g / 10min, a tensile strength of 32MPa, an elongation at break of 290%, a Shore hardness of 59D, and an elastic recovery rate of 97% at 100% elongation.

[0106] Example 5

[0107] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0108] A. Preparation of BOC-protected amino acids

[0109] Under ice bath conditions, 2.3 g L-glutamine, 10 mL water, 25 mL dioxane, and 1.41 g tert-butyl dicarbonate ((Boc)₂O) were added to a 100 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of amino acids, and the solution was extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-glutamine.

[0110] B. Synthesis of Microbranched PA6-based Elastomers

[0111] 113g caprolactam, 7g distilled water, 67.8g 1,3-cyclohexanedicarboxylic acid, and 3.39g N-BOC-glutamine were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 4 bar, and the reaction was continued at 280℃ for 2 hours to obtain carboxyl-terminated PA6 prepolymer.

[0112] After the above reaction is completed, 29g of ethylene glycol is added to the autoclave using a secondary feeding device, and the reaction continues for 1.5h at a temperature of 220℃, a pressure of 1.5bar, and a stirring speed of 200r / min.

[0113] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 120g of polycarbonate diol (M). n =4000 g / mol), 0.5 g tetrabutyl titanate, and the reaction was continued for 2 h at 280℃, 50 Pa, and 150 r / min. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomer.

[0114] C.PA6-based elastomer hard segment solid-phase crosslinking

[0115] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.009g of succinic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 130℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 16000g / mol, a melt index of 15.5g / 10min, a tensile strength of 36MPa, an elongation at break of 270%, a Shore hardness of 63D, and an elastic recovery rate of 95% at 100% elongation.

[0116] Example 6

[0117] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0118] A. Preparation of BOC-protected amino acids

[0119] Under ice bath conditions, 2.98 g of L-lysine, 12 mL of water, 27 mL of dioxane, and 5.64 g of tert-butyl dicarbonate ((Boc)₂O) were added to a 500 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of the amino acid, and the solution was extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-lysine.

[0120] B. Synthesis of Microbranched PA6-based Elastomers

[0121] 113g caprolactam, 25g 1,4-cyclohexanedicarboxylic acid, 8.5g distilled water, and 4.52g N-BOC-lysine were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 5 bar, and the reaction was continued at 270℃ for 2 hours to obtain carboxyl-terminated PA6 prepolymer.

[0122] After the above reaction is completed, 18g of hexanediol is added to the autoclave using a secondary feeding device, and the reaction is continued for 2 hours at a temperature of 210℃, a pressure of 1.8 bar, and a stirring speed of 200 r / min.

[0123] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 60g of polycaprolactone diol (M).n =6000 g / mol), 0.3 g of isopropyl titanate, and reacted for 4 h at 270 °C, 86 Pa, and 150 r / min. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomer.

[0124] C.PA6-based elastomer hard segment solid-phase crosslinking

[0125] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.012g of terephthalic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 140℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 16000g / mol, a melt index of 15.3g / 10min, a tensile strength of 35MPa, an elongation at break of 280%, a Shore hardness of 60D, and an elastic recovery rate of 98% at 100% elongation.

[0126] Example 7

[0127] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0128] A. Preparation of BOC-protected amino acids

[0129] Under ice bath conditions, 3.6 g of L-glutamic acid, 8 mL of water, 18 mL of dioxane, and 5.64 g of tert-butyl dicarbonate ((Boc)₂O) were added to a 500 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of the amino acid, and the solution was extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-glutamic acid.

[0130] B. Synthesis of Microbranched PA6-based Elastomers

[0131] 113g caprolactam, 24g succinic acid, 2.5g distilled water, and 1.13g N-BOC-glutamic acid were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 6 bar, and the reaction was continued at 265℃ for 2 hours to obtain carboxyl-terminated PA6 prepolymer.

[0132] After the above reaction is completed, 16g of propylene glycol is added to the autoclave using a secondary feeding device, and the reaction continues for 2 hours at a temperature of 200℃, a pressure of 2.3 bar, and a stirring speed of 200 r / min.

[0133] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 160g of polycaprolactone diol (M). n =4000 g / mol) and 0.8 g magnesium acetate were reacted at 250℃, 44 Pa, and 200 r / min for 2 h. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomer.

[0134] C.PA6-based elastomer hard segment solid-phase crosslinking

[0135] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.012g of isophthalic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 130℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 14000g / mol, a melt index of 19.3g / 10min, a tensile strength of 43MPa, an elongation at break of 230%, a Shore hardness of 68D, and an elastic recovery rate of 97% at 100% elongation.

[0136] Example 8

[0137] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0138] A. Preparation of BOC-protected amino acids

[0139] Under ice bath conditions, 1.21 g of L-asparagine, 10 mL of water, 25 mL of dioxane, and 1.41 g of tert-butyl dicarbonate ((Boc)₂O) were added to a 100 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of the amino acid, and the solution was extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-asparagine.

[0140] B. Synthesis of Microbranched PA6-based Elastomers

[0141] 113g caprolactam, 12g succinic acid, 5g distilled water, and 5.65g N-BOC-aspartic acid were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 4 bar, and the reaction was continued at 230℃ for 5 hours to obtain a carboxyl-terminated PA6 prepolymer.

[0142] After the above reaction is completed, 22g of pentanediol is added to the autoclave using a secondary feeding device, and the reaction continues for 2 hours at a temperature of 190℃, a pressure of 2.3 bar, and a stirring speed of 200 r / min.

[0143] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 120g of polytetrahydrofuran diol (M). n =4000 g / mol) and 0.1 g of antimony acetate were reacted at 260℃, 78 Pa, and 220 r / min for 2 h. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomers.

[0144] C.PA6-based elastomer hard segment solid-phase crosslinking

[0145] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.012g of adipic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 130℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 14000g / mol, a melt index of 18.7g / 10min, a tensile strength of 40MPa, an elongation at break of 300%, a Shore hardness of 60D, and an elastic recovery rate of 93% at 100% elongation.

[0146] Example 9

[0147] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0148] A. Preparation of BOC-protected amino acids

[0149] Under ice bath conditions, 1.47 g of L-glutamic acid, 10 mL of water, 25 mL of dioxane, and 1.41 g of tert-butyl dicarbonate ((Boc)₂O) were added to a 100 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of the amino acid, and the solution was extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-glutamic acid.

[0150] B. Synthesis of Microbranched PA6-based Elastomers

[0151] 113g caprolactam, 12g isophthalic acid, 5g distilled water, and 5.65g N-BOC-glutamic acid were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 8 bar, and the reaction was continued at 240℃ for 3 hours to obtain a carboxyl-terminated PA6 prepolymer.

[0152] After the above reaction is completed, 25g of butanediol is added to the autoclave using a secondary feeding device, and the reaction continues for 2 hours at a temperature of 200℃, a pressure of 1.9 bar, and a stirring speed of 230r / min.

[0153] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 120g of polytetrahydrofuran (M). n =6000 g / mol) and 0.5 g of antimony acetate were reacted at 265 °C, 88 Pa, and 250 r / min for 4 h. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomers.

[0154] C.PA6-based elastomer hard segment solid-phase crosslinking

[0155] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.012g of sebacic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 150℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 18000g / mol, a melt index of 12.3g / 10min, a tensile strength of 38MPa, an elongation at break of 260%, a Shore hardness of 64D, and an elastic recovery rate of 98% at 100% elongation.

[0156] Example 10

[0157] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0158] A. Preparation of BOC-protected amino acids

[0159] Under ice bath conditions, 2.04 g of L-asparagine, 10 mL of water, 25 mL of dioxane, and 1.41 g of tert-butyl dicarbonate ((Boc)₂O) were added to a 100 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of the amino acid, and the solution was extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-asparagine.

[0160] B. Synthesis of Microbranched PA6-based Elastomers

[0161] 113g caprolactam, 20g isophthalic acid, 8g distilled water, and 6.78g N-BOC-aspartic acid were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 7 bar, and the reaction was continued at 230℃ for 3 hours to obtain carboxyl-terminated PA6 prepolymer.

[0162] After the above reaction is completed, 25g of butanediol is added to the autoclave using a secondary feeding device, and the reaction continues for 2 hours at a temperature of 210℃, a pressure of 1.8 bar, and a stirring speed of 240 r / min.

[0163] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 50g of polypropylene glycol (M). n =4000 g / mol) and 0.2 g magnesium acetate were reacted at 280℃, 78 Pa, and 280 r / min for 4 h. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomers.

[0164] C.PA6-based elastomer hard segment solid-phase crosslinking

[0165] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.012g of succinic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 140℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 18000g / mol, a melt index of 12.4g / 10min, a tensile strength of 45MPa, an elongation at break of 200%, a Shore hardness of 70D, and an elastic recovery rate of 96% at 100% elongation.

[0166] Example 11

[0167] The preparation method of high-resilience PA6-based polyamide thermoplastic elastomer includes the following specific steps:

[0168] A. Preparation of BOC-protected amino acids

[0169] Under ice bath conditions, 2.04 g of L-asparagine, 10 mL of water, 25 mL of dioxane, and 1.41 g of tert-butyl dicarbonate ((Boc)₂O) were added to a 100 mL four-necked flask equipped with a mechanical stirrer. Then, 15 mL of potassium carbonate aqueous solution (concentration 0.67 mmol / mL) was slowly added dropwise through a constant-pressure dropping funnel over approximately 10 minutes. The reaction was continued until the solution was completely clear. Water and dioxane were then removed from the reaction system by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed twice with ether. The pH of the solution was adjusted to the isoelectric point of the amino acid, and the solution was extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate and filtered. The resulting filtrate was concentrated under reduced pressure and dried to obtain N-BOC-asparagine.

[0170] B. Synthesis of Microbranched PA6-based Elastomers

[0171] 113g caprolactam, 28g succinic acid, 6g distilled water, and 1.13g N-BOC-aspartic acid were added to a 500mL autoclave. After purging the reactor with nitrogen to replace the air, the pressure was increased to 6 bar, and the reaction was continued at 250℃ for 2 hours to obtain a carboxyl-terminated PA6 prepolymer.

[0172] After the above reaction is completed, 24g of ethylene glycol is added to the autoclave using a secondary feeding device, and the reaction continues for 2 hours at a temperature of 230℃, a pressure of 2.8 bar, and a stirring speed of 250 r / min.

[0173] After the above reaction is complete, reduce the pressure to atmospheric pressure and add 50g of polypropylene glycol (M). n=4000 g / mol) and 0.3 g magnesium acetate were reacted at 280℃, 78 Pa, and 280 r / min for 4 h. Afterward, the pressure in the reactor was balanced to atmospheric pressure, and the mixture was cast into strips, drawn into strands, and granulated to obtain microbranched PA6 elastomer.

[0174] C.PA6-based elastomer hard segment solid-phase crosslinking

[0175] 10g of microbranched PA6 elastomer was dissolved in 100mL of hexafluoroisopropanol. 20mL of concentrated hydrochloric acid was added dropwise to the solution, and the mixture was reacted at room temperature for 1 hour. Then, 0.012g of succinic acid was added to the mixture, and under thorough stirring, the mixture was added dropwise to ice-cold methanol to precipitate, filtered, and dried. The resulting sample was placed in a vacuum drum drying oven and reacted at 140℃ for 24 hours (hard segment solid-phase crosslinking reaction) to obtain a high-resilience PA6 thermoplastic elastomer. The high-resilience PA6 thermoplastic elastomer obtained after drying had a number-average molecular weight of 18000g / mol, a melt index of 12.1g / 10min, a tensile strength of 60MPa, an elongation at break of 200%, a Shore hardness of 40D, and an elastic recovery rate of 98% at 100% elongation.

Claims

1. A thermoplastic elastomer, characterized in that, The thermoplastic elastomer includes an elastomer body and a chemical framework connecting the elastomer body; wherein the elastomer body includes hard segments and soft segments, and the hard segments are cross-linked with dicarboxylic acids to form the chemical framework connecting the elastomer body; The general structural formula of the hard segment is: Where R includes CO(CH2) x NH, CO(CH2) x NHCONH, CO(CH2) x CO, CO(CH2) x One of CONH; m≥4, n≥1; x≥1; The soft segment is polyethylene glycol.

2. A method for preparing a thermoplastic elastomer, comprising: (1) Under ice bath conditions, amino acids, water, dioxane, and tert-butyl dicarbonate (Boc)2O were mixed, and then potassium carbonate aqueous solution was added. The reaction was continued until the solution was clear, then purified and dried to obtain N-BOC-amino acids. (2) Mix caprolactam, water, N-BOC-amino acid and capping agent, react under protective gas conditions to obtain carboxyl-capped PA6 prepolymer, add diol to react, and then add polydiol and catalyst to react to obtain PA6 elastomer. (3) Mix the PA6 elastomer and solvent from step (2), add hydrochloric acid and react, then add dicarboxylic acid to carry out cross-linking reaction to obtain thermoplastic elastomer.

3. The preparation method according to claim 2, characterized in that, In step (1), the amino acids are 0.5-5 parts by weight, water is 8-12 parts, dioxane is 18-27 parts, and tert-butyl dicarbonate (Boc)2O is 1-8 parts. The amino acid mentioned in step (1) is an L-amino acid; the L-amino acid includes one or more of L-lysine, L-citrulline, L-glutamic acid, L-aspartic acid, and L-glutamine.

4. The preparation method according to claim 2, characterized in that, In step (1), the potassium carbonate aqueous solution is added dropwise, and the addition is completed in 8-15 minutes. The purification in step (1) includes: removing water and dioxane from the reaction system by vacuum distillation to obtain a white solid. After the solid is dissolved in water and washed with ether, the pH of the solution is adjusted to the isoelectric point of amino acids. After extraction with ethyl acetate, the organic layers are combined, dried with anhydrous sodium sulfate, filtered, and the resulting filtrate is concentrated.

5. The preparation method according to claim 2, characterized in that, In step (2), by weight, there are 100-120 parts of caprolactam, 1-10 parts of water, 1-25 parts of N-BOC-amino acid, 1-60 parts of capping agent, 1-100 parts of diol, 20-200 parts of polydiol, and 0.1-10 parts of catalyst.

6. The preparation method according to claim 2, characterized in that, The capping agent in step (2) includes one or more of succinic acid, adipic acid, sebacic acid, dodecanoic acid, terephthalic acid, isophthalic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. The diol in step (2) includes one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol; the polydiol in step (2) includes one or more of polyethylene glycol, polypropylene glycol, polytetrahydrofuran glycol, polycaprolactone glycol, and polycarbonate glycol; wherein the number average molecular weight of the polydiol is 500-8000 g / mol; The catalyst in step (2) is a transesterification catalyst; the transesterification catalyst includes one or more of tetrabutyl titanate, isopropyl titanate, zinc acetate, manganese acetate, antimony acetate, magnesium acetate, sodium acetate, and antimony trioxide.

7. The preparation method according to claim 2, characterized in that, The protective gas in step (2) is nitrogen; In step (2), caprolactam, water, N-BOC-amino acid and capping agent are mixed and reacted under protective gas conditions, wherein the reaction is carried out under pressure of 1-10 bar at 220-240°C for 1-5 hours. In step (2), a diol is added for reaction, wherein the reaction is carried out at 220-240°C, at a pressure of 2-6 bar, and at a stirring speed of 50-500 r / min for 1-3 hours. In step (2), polydiol and catalyst are added for reaction, wherein the reaction is carried out at 220-280℃, 20-200Pa, and 50-500r / min for 0.5-5h.

8. The preparation method according to claim 2, characterized in that, In step (3), by weight, there are 10 parts of PA6 elastomer and 0.005 to 0.03 parts of dicarboxylic acid; the solvent is hexafluoroisopropanol. The dicarboxylic acids include one or more of succinic acid, adipic acid, sebacic acid, terephthalic acid, and isophthalic acid.

9. The preparation method according to claim 2, characterized in that, After adding hydrochloric acid in step (3), the reaction is carried out at room temperature for 1-2 hours; after adding dicarboxylic acid in step (3), precipitation, filtration, drying, and then cross-linking reaction are carried out. In step (3), the crosslinking reaction is carried out at 120-160℃ for 10-24 hours.

10. The application of the thermoplastic elastomer of claim 1 in the textile field.

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