High-resilience PA6 series polyamide thermoplastic elastomer as well as preparation method and application thereof

Abstract

The invention relates to a high-resilience PA6 series polyamide thermoplastic elastomer as well as a preparation method and application thereof. The defects of low breaking strength, poor resilience and the like caused by insufficient intermolecular binding force of a traditional PA6 series elastomer are overcome. The elastomer disclosed by the invention is stable and controllable, high in breaking strength, excellent in rebound resilience and adjustable in shore hardness, and overcomes the defects in the prior art.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials, and particularly relates to a high-resilience PA6 series polyamide thermoplastic elastomer and a preparation method and application thereof. Background Art

[0002] Thermoplastic elastomers (TPEs) are a type of polymer material that exhibits rubber elasticity at room temperature and can be plasticized and formed at high temperatures. Its macromolecular chain is mainly composed of plastic segments (hard segments) and rubber segments (soft segments). Its hard segments have strong intermolecular bonding forces and form physical "crosslinking points" at room temperature, which determine the strength of the material; the soft segments are chain segment structures with strong free rotation ability, which give the material good elasticity. In addition, due to the thermal reversibility of the hard segment physical crosslinking network, TPEs exhibit good melt processability.

[0003] PA6 series polyamide thermoplastic elastomer is a semi-crystalline block copolymer with PA6 as hard segment and polyether as soft segment. Its synthesis methods can generally be divided into two categories: anionic ring-opening polymerization and hydrolysis ring-opening polymerization. Anionic ring-opening polymerization has high requirements on raw material purity, and most of them require the use of highly toxic activator phosgene, which has huge safety risks in the production process. In addition, the product performance is poor and it is difficult to meet the application requirements in certain fields. Hydrolysis ring-opening polymerization has the advantages of excellent product performance and safe and controllable preparation process. It is a synthesis method currently commonly used in the industry.

[0004] Patent CN 101747510A prepares PA6 prepolymer by introducing diisocyanate during the hydrolysis and ring-opening polymerization of caprolactam, and then synthesizes PA6-based polyamide thermoplastic elastomer through esterification and polycondensation between the prepolymer and the polyether soft segment. This method requires the addition of diisocyanate at high temperature, and the production process is very likely to cause harm to the human body.

[0005] Patent CN 106565953 A, based on the hydrolysis ring-opening technology of caprolactam, invented a new synthesis method of PA6-based thermoplastic elastomers - the "three-step" synthesis method, that is, using caprolactam, dicarboxylic acid, diol, and polyether diol as raw materials, through the synthesis of carboxyl-terminated PA6 prepolymers, carboxyl-terminated esterification, and polyether diol copolymerization, an elastomer with excellent thermodynamic properties was prepared. However, due to the weak intermolecular bonding force, the macromolecular chain is prone to slip during the stretching process, and the elasticity of the elastomer is insufficient, which cannot meet the application requirements in specific fields.

[0006] Patent CN 107698771A discloses a PA6-based thermoplastic elastomer with a micro-crosslinked structure and its preparation method, that is, by introducing an appropriate amount of crosslinked structure into the elastomer to increase the binding force between macromolecules, thereby improving its resilience. However, due to the limitations of the synthesis method, the position of the crosslinking points in the elastomer prepared based on this method cannot be controlled (distributed in the soft and hard phases), and the melt processability of the related products is poor, and cannot be applied to certain specific fields.

[0007] In summary, PA6 thermoplastic elastomers prepared by the above methods have poor resilience due to the weak bonding force of the physical crosslinking points of the hard segment, the macromolecular chains are easy to slip during the stretching process. The elastomers prepared based on the traditional chemical crosslinking method have better resilience, but due to the "random" distribution of its chemical crosslinking points, the elongation at break of the related products is low and the melt processability is poor, which limits its further application in the industrial field. Summary of the invention

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

[0009] The present invention provides a thermoplastic elastomer, which comprises an elastomer body and a chemical framework connecting the elastomer body; wherein the elastomer body comprises a hard segment and a soft segment, and the chemical framework connecting the elastomer body is formed by a cross-linking reaction between a dicarboxylic acid and the hard segment.

[0010] The general structure of the hard segment is:

[0011] Where R includes CO(CH 2 )xNH, CO(CH 2 ) x NHCONH, CO(CH 2 ) x CO, CO(CH 2 )xCONH; m≥4, n≥1; x≥1; the soft segment is a polyglycol.

[0012] Furthermore, x≥2.

[0013] Furthermore, wherein R comprises CO(CH 2 ) 5 NH, CO(CH 2 ) 3 NHCONH, CO(CH 2 ) 3 CO, CO(CH 2 ) 2 CO, CO(CH 2 ) 3One of CONH; m ≥ 4, n ≥ 1.

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

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

[0016] Further, the amino acid is selected from L-amino acids, wherein the L-amino acid includes 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 dicarboxylic acid, which becomes the chemical framework connecting the elastomer macromolecular chains through the amidation reaction with "de-BOC amino".

[0019] It is a hard segment, and its general structural formula is:

[0020]

[0021] Among them, m≥4, n≥1.

[0022] in, Derived from BOC protected amino acids. The amino acids are selected from L-amino acids, and the L-amino acids include 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 polyglycol with a molecular weight range of 500-8000 g / mol, accounting for 10%-90% of the total elastomer

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

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

[0026] Amino acid, water, dioxane, tert-butyl dicarbonate (Boc) were mixed under ice bath conditions. 2 O mixed, then adding potassium carbonate aqueous solution, continuing the reaction until the solution is clear, purifying, and drying to obtain N-BOC-amino acid;

[0027] (2) Synthesis of micro-branched PA6 elastomers

[0028] Caprolactam, water, N-BOC-amino acid and end-capping agent are mixed, reacted under protective gas conditions to obtain a carboxyl-terminated PA6 prepolymer, diol is added to react, and then polyglycol and a catalyst are added to react to obtain a PA6 elastomer (i.e., a slightly branched PA6 elastomer);

[0029] (3) Deprotection of BOC from the hard segment “branched amino” and solid phase crosslinking of PA6 elastomer hard segment

[0030] The PA6 elastomer and solvent of step (2) are mixed, hydrochloric acid is added to react, and then a 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 acid is 0.5-5 parts, water is 8-12 parts, dioxane is 18-27 parts, tert-butyl dicarbonate (Boc) is 10-20 parts, and the mixture is 10-20 parts. 2 O1-8 parts;

[0032] In the 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, the potassium carbonate aqueous solution is added dropwise in step (1) over a period of 8-15 minutes.

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

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

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

[0038] In step (2), the end-capping agent includes one or more of succinic acid, adipic acid, sebacic acid, dodecanedioic 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, butylene glycol, pentanediol, and hexanediol;

[0040] Preferably, the polyglycol in step (2) comprises one or more of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycaprolactone glycol, and polycarbonate glycol; wherein the number average molecular weight of the polyglycol is 500 to 8000 g / mol;

[0041] Preferably, the catalyst in step (2) is an ester exchange catalyst; the ester exchange 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 end-capping agent are mixed and reacted under protective gas conditions, wherein the reaction is pressurized to 1-10 bar and reacted at 220-240° C. for 1-5 hours;

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

[0045] Preferably, in step (2), polyglycol 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 an autoclave.

[0047] In step (2), caprolactam, water, N-BOC-amino acid and end-capping agent are mixed and reacted under protective gas conditions to obtain a carboxyl-terminated PA6 prepolymer, diol is added for reaction, and then polyglycol and catalyst are added for reaction, the pressure is balanced to normal pressure, and a PA6 elastomer is obtained by casting a strip, drawing a strip and pelletizing.

[0048] Preferably, in the step (3), the PA6 elastomer is 10 parts and the dicarboxylic acid is 0.005-0.03 parts by weight; 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), the hydrochloric acid is added and reacted at room temperature for 1-2 hours;

[0051] Preferably, after adding the dicarboxylic acid in step (3), the mixed system is precipitated, filtered, dried, and then subjected to a cross-linking reaction; for example, after adding the dicarboxylic acid, the mixed system is dripped into ice methanol under sufficient stirring to precipitate, filter, and dry.

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

[0053] The invention provides application of the thermoplastic elastomer in the textile field.

[0054] The thermoplastic elastomer in the present invention is a block copolymer composed of soft and hard segments alternately connected. The soft segment can produce a large deformation under a small stress, so that the fiber is easy to be stretched, and the hard segment that is difficult to deform can be used as a node when the soft segment is stretched and rebounded. The joint action of the soft and hard segments enables the elastomer to obtain higher elasticity. The cross-linked network structure is introduced directionally into the hard segment of the elastomer, so that the intermolecular bonding force of the hard segment is enhanced. Finally, the elastomer of the present invention is stable and controllable, and has high fracture strength, excellent resilience, adjustable Shore hardness, and good melt processability, which makes up for the shortcomings of the prior art.

[0055] The present invention provides a high-resilience PA6 series polyamide thermoplastic elastomer, which is prepared by introducing BOC protected amino acid in the process of hydrolysis and ring opening of caprolactam to prepare double-terminal carboxyl PA6 prepolymer, then preparing micro-branched PA6 series elastomer by esterification between prepolymer and diol and ester exchange reaction between related products and polyglycol, and finally preparing hard segment micro-crosslinked PA6 series elastomer by amidation reaction between "de-BOC amino group" and dicarboxylic acid (solid phase crosslinking process). The high-resilience PA6 series polyamide thermoplastic elastomer is a polyetheramide ester polymer resin with micro-crosslinked structure in hard segment, high breaking strength, excellent resilience, etc.

[0056] The present invention mainly includes the steps of preparing BOC protected amino acids, synthesizing micro-branched PA6 elastomers, removing BOC protection of the hard segment "branched amino groups", and solid phase crosslinking. Based on the soft and hard segment block copolymers of the elastomer of the present invention and the directional introduction of a cross-linked network structure into the hard segment of the elastomer, the defects of low breaking strength and poor resilience of traditional PA6 elastomers due to insufficient intermolecular bonding force are solved. In addition, the elastomer prepared based on this method is stable and controllable, and has high breaking strength, excellent resilience (elastic recovery rate reaches more than 95% when elongated by 100%), and adjustable Shore hardness, which makes up for the shortcomings of the prior art.

[0057] Beneficial Effects

[0058] The present invention is based on the PA6 series thermoplastic elastomer hydrolysis ring-opening process, combined with the polymer chain branching and solid phase crosslinking theory, to develop a complete set of preparation technology for high elastic PA6 series thermoplastic elastomer. The technology has the advantages of mild reaction conditions and stable process, which makes up for the shortcomings of the existing technology. In addition, the elastomer prepared based on this technology has the advantages of high breaking strength, excellent resilience (elastic recovery rate ≥95% when elongated 100%), good melt processability, adjustable Shore hardness, etc., which can better meet the processing and application requirements in specific fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 Schematic diagram of the structure of high-resilience PA6 thermoplastic elastomer. DETAILED DESCRIPTION

[0060] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0061] The molecular weight of the polyglycol in the present invention refers to the number average molecular weight, and the unit is (g / mol). All raw materials in the present invention are commercially available products.

[0062] In the present invention, Agilent 1260 Infinity II gel permeation chromatography (GPC) was used to determine the number average molecular weight (M n ), HFIP solution with a concentration of 1 mg / mL sodium trifluoroacetate was used as the eluent (flow rate 0.3 mL / min). Polymethyl methacrylate (PMMA) was used for GPC curve calibration.

[0063] In the present invention, a melt index meter is used to measure the melt index of a sample at 240° C. and a preload of 2160 g to obtain a corresponding melt index.

[0064] In the present invention, the elastomer was subjected to tensile and cyclic tensile tests at room temperature using a WDW 3020 electric universal testing machine (Sansi, China). Dumbbell-shaped specimens with a thickness of 2 mm and a width of 4 mm were prepared by hot pressing. 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 hardness of the elastomer in the present invention is measured by Shore Durometer LX-A and LX-D (Handan, China).

[0066] Example 1

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

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

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

[0070] B. Synthesis of Microbranched PA6 Elastomers

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

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

[0073] After the reaction is completed, the pressure is reduced to normal pressure, and 22.6 g of polyethylene glycol (M n =8000g / mol), 0.1g tetrabutyl titanate, and continue to react for 0.5h at 280°C, 20Pa, 150r / min. Then, balance the pressure of the reactor to normal pressure, cast strips, draw strips, and cut into pellets to obtain a slightly branched PA6 elastomer.

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

[0075] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, add 20mL of concentrated hydrochloric acid dropwise to the solution, and react at room temperature for 1h. Then add 0.005g of succinic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration, and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 120°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 14000g / mol, the melt index is 18.3g / 10min, the tensile strength is 29MPa, the elongation at break is 200%, the Shore hardness is 57D, and the elastic recovery rate reaches 95% at 100% elongation.

[0076] Example 2

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

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

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

[0080] B. Synthesis of Microbranched PA6 Elastomers

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

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

[0083] After the above-mentioned reaction is completed, the pressure is reduced to normal pressure, and 256g polytetrahydrofuran diol (Mn =500g / mol), 0.5g sodium acetate, and continue to react for 5h at 220°C, 200Pa, and 200r / min. After that, balance the pressure of the reactor to normal pressure, cast strips, draw strips, and pelletize to obtain a slightly branched PA6 elastomer.

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

[0085] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, add 20mL of concentrated hydrochloric acid dropwise to the solution, and react at room temperature for 1h. Then add 0.03g of succinic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration, and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 160°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 15000g / mol, the melt index is 17.2g / 10min, the tensile strength is 42MPa, the elongation at break is 210%, the Shore hardness is 54D, and the elastic recovery rate reaches 94% at 100% elongation.

[0086] Example 3

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

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

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

[0090] B. Synthesis of Microbranched PA6 Elastomers

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

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

[0093] After the above reaction is completed, the pressure is reduced to normal pressure, and 100 g of polytetrahydrofuran diol (M n =3000g / mol), 1.13g antimony trioxide, and continue to react for 2h at 220℃, 75Pa, 500r / min. Then, balance the pressure of the reactor to normal pressure, cast strips, draw strips, and cut into pellets to obtain a slightly branched PA6 elastomer.

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

[0095] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, add 20mL of concentrated hydrochloric acid dropwise to the solution, and react at room temperature for 1h. Then add 0.01g of sebacic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration, and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 150°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 17000g / mol, the melt index is 13.3g / 10min, the tensile strength is 26MPa, the elongation at break is 350%, the Shore hardness is 50D, and the elastic recovery rate reaches 96% at 100% elongation.

[0096] Example 4

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

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

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

[0100] B. Synthesis of Microbranched PA6 Elastomers

[0101] 113 g of caprolactam, 4 g of distilled water, 20 g of dodecanedioic acid and 2.26 g of N-BOC-aspartic acid were added to a 500 mL autoclave. After nitrogen was introduced to replace the air in the reactor, the pressure was increased to 10 bar and the reaction was continued at 260° C. for 4 h to obtain a carboxyl-terminated PA6 prepolymer.

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

[0103] After the reaction is completed, the pressure is reduced to normal pressure, and 100 g of polyethylene glycol (M n =4000g / mol), 0.3g antimony acetate, and continue to react for 2h at 250℃, 50Pa, 50r / min. Then, balance the pressure of the reactor to normal pressure, cast strips, draw strips, and pelletize to obtain a slightly branched PA6 elastomer.

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

[0105] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, take 20mL of concentrated hydrochloric acid and add it dropwise to the solution, and react at room temperature for 1h. Then add 0.01g of terephthalic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 120°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 16000g / mol, the melt index is 14.3g / 10min, the tensile strength is 32MPa, the elongation at break is 290%, the Shore hardness is 59D, and the elastic recovery rate reaches 97% at 100% elongation.

[0106] Example 5

[0107] The preparation method of high-resilience PA6 polyamide thermoplastic elastomer comprises 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, 1.41 g tert-butyl dicarbonate (Boc) were added to a 100 mL four-necked flask equipped with a mechanical stirrer. 2 O). Then, 15 mL of potassium carbonate aqueous solution (concentration of 0.67 mmol / mL) was slowly added dropwise through a constant pressure dropping funnel, and the dropping was completed in about 10 min. The reaction was continued until the solution was completely clarified, and water and dioxane in the reaction system were removed by vacuum distillation to obtain a white solid. The obtained solid was dissolved in water and washed with ether twice, and the pH value of the solution was adjusted to the isoelectric point of the amino acid, extracted with ethyl acetate, and the organic layers were combined, dried with anhydrous sodium sulfate, and filtered. The obtained filtrate was concentrated under reduced pressure and dried to obtain N-BOC-glutamine.

[0110] B. Synthesis of Microbranched PA6 Elastomers

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

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

[0113] After the above reaction is completed, the pressure is reduced to normal pressure, and 120g of polycarbonate diol (M n =4000g / mol), 0.5g tetrabutyl titanate, and continue to react for 2h at 280℃, 50Pa, 150r / min. Then, balance the pressure of the reactor to normal pressure, cast strips, draw strips, and cut into pellets to obtain a slightly branched PA6 elastomer.

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

[0115] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, add 20mL of concentrated hydrochloric acid dropwise to the solution, and react at room temperature for 1h. Then add 0.009g of succinic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration, and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 130°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 16000g / mol, the melt index is 15.5g / 10min, the tensile strength is 36MPa, the elongation at break is 270%, the Shore hardness is 63D, and the elastic recovery rate reaches 95% at 100% elongation.

[0116] Example 6

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

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

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

[0120] B. Synthesis of Microbranched PA6 Elastomers

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

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

[0123] After the reaction is completed, the pressure is reduced to normal pressure, and 60 g of polycaprolactone diol (M n =6000g / mol), 0.3g isopropyl titanate, and the reaction is continued for 4h at 270℃, 86Pa, 150r / min. After that, the pressure of the reactor is balanced to normal pressure, and the strip is cast, drawn and pelletized to obtain the micro-branched PA6 elastomer.

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

[0125] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, take 20mL of concentrated hydrochloric acid and add it dropwise to the solution, and react at room temperature for 1h. Then add 0.012g of terephthalic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 140°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 16000g / mol, the melt index is 15.3g / 10min, the tensile strength is 35MPa, the elongation at break is 280%, the Shore hardness is 60D, and the elastic recovery rate reaches 98% at 100% elongation.

[0126] Example 7

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

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

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

[0130] B. Synthesis of Microbranched PA6 Elastomers

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

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

[0133] After the reaction is completed, the pressure is reduced to normal pressure, and 160 g of polycaprolactone diol (M n =4000g / mol), 0.8g magnesium acetate, and continue to react for 2h at 250°C, 44Pa, 200r / min. Then, balance the pressure of the reactor to normal pressure, cast strips, draw strips, and cut into pellets to obtain a slightly branched PA6 elastomer.

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

[0135] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, take 20mL of concentrated hydrochloric acid and add it dropwise to the solution, and react at room temperature for 1h. Then add 0.012g of isophthalic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 130°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 14000g / mol, the melt index is 19.3g / 10min, the tensile strength is 43MPa, the elongation at break is 230%, the Shore hardness is 68D, and the elastic recovery rate reaches 97% at 100% elongation.

[0136] Example 8

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

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

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

[0140] B. Synthesis of Microbranched PA6 Elastomers

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

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

[0143] After the above-mentioned reaction is completed, the pressure is reduced to normal pressure, and 120g polytetrahydrofuran diol (M n =4000g / mol), 0.1g antimony acetate, and continue to react for 2h at 260℃, 78Pa, 220r / min. Then, balance the pressure of the reactor to normal pressure, cast strips, draw strips, and pelletize to obtain a slightly branched PA6 elastomer.

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

[0145] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, add 20mL of concentrated hydrochloric acid dropwise to the solution, and react at room temperature for 1h. Then add 0.012g of adipic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration, and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 130°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 14000g / mol, the melt index is 18.7g / 10min, the tensile strength is 40MPa, the elongation at break is 300%, the Shore hardness is 60D, and the elastic recovery rate reaches 93% at 100% elongation.

[0146] Example 9

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

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

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

[0150] B. Synthesis of Microbranched PA6 Elastomers

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

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

[0153] After the reaction is completed, the pressure is reduced to normal pressure, and 120 g of polytetrahydrofuran (M n =6000g / mol), 0.5g antimony acetate, and continue to react for 4h at 265℃, 88Pa, 250r / min. Then, balance the pressure of the reactor to normal pressure, cast strips, draw strips, and cut into pellets to obtain a slightly branched PA6 elastomer.

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

[0155] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, add 20mL of concentrated hydrochloric acid dropwise to the solution, and react at room temperature for 1h. Then add 0.012g of sebacic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration, and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 150°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 18000g / mol, the melt index is 12.3g / 10min, the tensile strength is 38MPa, the elongation at break is 260%, the Shore hardness is 64D, and the elastic recovery rate reaches 98% at 100% elongation.

[0156] Example 10

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

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

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

[0160] B. Synthesis of Microbranched PA6 Elastomers

[0161] 113 g of caprolactam, 20 g of isophthalic acid, 8 g of distilled water and 6.78 g of N-BOC-aspartic acid were added to a 500 mL autoclave. Nitrogen was introduced to replace the air in the reactor, and the pressure was increased to 7 bar. The reaction was continued at 230 ° C for 3 h to obtain a carboxyl-terminated PA6 prepolymer.

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

[0163] After the reaction is completed, the pressure is reduced to normal pressure, and 50 g of polypropylene glycol (Mn =4000g / mol), 0.2g magnesium acetate, and continue to react for 4h at 280℃, 78Pa, 280r / min. Then, balance the pressure of the reactor to normal pressure, cast strips, draw strips, and cut into pellets to obtain a slightly branched PA6 elastomer.

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

[0165] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, add 20mL of concentrated hydrochloric acid dropwise to the solution, and react at room temperature for 1h. Then add 0.012g of succinic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration, and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 140°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 18000g / mol, the melt index is 12.4g / 10min, the tensile strength is 45MPa, the elongation at break is 200%, the Shore hardness is 70D, and the elastic recovery rate reaches 96% at 100% elongation.

[0166] Embodiment 11

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

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

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

[0170] B. Synthesis of Microbranched PA6 Elastomers

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

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

[0173] After the reaction is completed, the pressure is reduced to normal pressure, and 50 g of polypropylene glycol (M n =4000g / mol), 0.3g magnesium acetate, and continue to react for 4h at 280℃, 78Pa, 280r / min. Then, balance the pressure of the reactor to normal pressure, cast strips, draw strips, and cut into pellets to obtain a slightly branched PA6 elastomer.

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

[0175] Dissolve 10g of micro-branched PA6 elastomer in 100mL of hexafluoroisopropanol, add 20mL of concentrated hydrochloric acid dropwise to the solution, and react at room temperature for 1h. Then add 0.012g of succinic acid to the mixed solution, add the mixed solution dropwise to ice methanol for precipitation, filtration, and drying under sufficient stirring. Place the obtained sample in a vacuum drum drying oven and react at 140°C for 24h (hard segment solid phase crosslinking reaction) to obtain a high-rebound PA6 thermoplastic elastomer. The number average molecular weight of the high-rebound PA6 thermoplastic elastomer obtained after drying is 18000g / mol, the melt index is 12.1g / 10min, the tensile strength is 60MPa, the elongation at break is 200%, the Shore hardness is 40D, and the elastic recovery rate reaches 98% at 100% elongation.

Claims

1. A thermoplastic elastomer, characterized in that: The thermoplastic elastomer comprises an elastomer body and a chemical framework connecting the elastomer body; wherein the elastomer body comprises a hard segment and a soft segment, and the chemical framework connecting the elastomer body is formed by cross-linking the dicarboxylic acid with the hard segment.

2. The thermoplastic elastomer according to claim 1, characterized in that: 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 a polyglycol.

3. A method for preparing a thermoplastic elastomer, comprising: (1) Mixing amino acid, water, dioxane, and tert-butyl dicarbonate (Boc)2O under ice bath conditions, then adding potassium carbonate aqueous solution, continuing the reaction until the solution becomes clear, purifying, and drying to obtain N-BOC-amino acid; (2) mixing caprolactam, water, N-BOC-amino acid and a capping agent, reacting them under protective gas conditions to obtain a carboxyl-terminated PA6 prepolymer, adding a diol to react, and then adding a polyglycol and a catalyst to react to obtain a PA6 elastomer; (3) The PA6 elastomer and solvent of step (2) are mixed, hydrochloric acid is added to react, and then a dicarboxylic acid is added to carry out a cross-linking reaction to obtain a thermoplastic elastomer.

4. The preparation method according to claim 3, characterized in that: In the step (1), the amino acid is 0.5-5 parts, water is 8-12 parts, dioxane is 18-27 parts, and tert-butyl dicarbonate (Boc)2O is 1-8 parts by weight; The amino acid 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.

5. The preparation method according to claim 3, characterized in that: The potassium carbonate aqueous solution is added dropwise in the step (1) over a period of 8-15 minutes. The purification in step (1) comprises: removing water and dioxane in the reaction system by vacuum distillation to obtain a white solid, dissolving the solid in water and washing with ether, adjusting the pH value of the solution to the isoelectric point of the amino acid, extracting with ethyl acetate, combining the organic layers, drying with anhydrous sodium sulfate, filtering, and concentrating the obtained filtrate.

6. The preparation method according to claim 3, characterized in that: In the step (2), the following components are added by weight: 100-120 parts of caprolactam, 1-10 parts of water, 1-25 parts of N-BOC-amino acid, 1-60 parts of end-capping agent, 1-100 parts of diol, 20-200 parts of polyglycol, and 0.1-10 parts of catalyst.

7. The preparation method according to claim 3, characterized in that: In step (2), the end-capping agent includes one or more of succinic acid, adipic acid, sebacic acid, dodecanedioic 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, butylene glycol, pentanediol, and hexanediol; the polyglycol in step (2) includes one or more of polyethylene glycol, polypropylene glycol, polytetrahydrofuran diol, polycaprolactone diol, and polycarbonate diol; wherein the number average molecular weight of the polyglycol is 500 to 8000 g / mol; The catalyst in step (2) is an ester exchange catalyst; the ester exchange catalyst includes one or more of tetrabutyl titanate, isopropyl titanate, zinc acetate, manganese acetate, antimony acetate, magnesium acetate, sodium acetate, and antimony trioxide.

8. The preparation method according to claim 3, characterized in that: In the step (2), the protective gas is nitrogen; In the step (2), caprolactam, water, N-BOC-amino acid and end-capping agent are mixed and reacted under protective gas conditions, wherein the reaction is pressurized to 1-10 bar and reacted at 220-240° C. for 1-5 hours; In the step (2), a diol is added for reaction at 220-240° C., a pressure of 2-6 bar, and a stirring speed of 50-500 r / min for 1-3 hours; In the step (2), polyglycol 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.

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

10. The preparation method according to claim 3, 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; The cross-linking reaction in step (3) is carried out at 120-160° C. for 10-24 hours.

11. Use of the thermoplastic elastomer according to claim 1 in the textile field.

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