Polyamide elastomer and preparation method thereof

Abstract

The invention provides a polyamide elastomer and a preparation method thereof. The method comprises the following steps: (1) under the action of a first catalyst, carrying out condensation polymerization on a poly-diol compound and a binary acid monomer in a solvent to obtain an end-capping reagent; (2) under the action of a second catalyst, an end-capping reagent and a comonomer are subjected to a contact reaction, and a polyamide block is obtained; and (3) in the presence of a stabilizer and under the action of a third catalyst, carrying out contact reaction on the soft segment and the polyamide block to obtain the polyamide elastomer, wherein the polydihydric alcohol compound is polyalkylene ether glycol with the number-average molecular weight of 150-2000, and the stoichiometric ratio of the polydihydric alcohol compound to the binary acid monomer is 1: (2.0-2.4); the comonomer is C4-C12 lactam and / or C4-C12 amino carboxylic acid; and the soft segment is a hydroxyl-terminated diol polymer. According to the invention, the performance loss of the hard-segment-dominated material is not caused on the basis of improving the soft-segment-dominated material mechanical property of the product, and the polyamide elastomer product with excellent comprehensive performance is obtained.

Description

Technical Field

[0001] This invention relates to the field of polymer material preparation technology, specifically to a polyamide elastomer and its preparation method. Background Technology

[0002] Polyamide elastomers (TPAEs) are high-performance thermoplastic elastomers formed by copolymerizing rigid polyamide (PA) segments with flexible polyether / polyester segments. Due to their unique microphase separation structure, their macroscopic mechanical properties combine the rigidity of the polyamide hard segments with the flexibility and reversible deformation capability of the polyether / polyester soft segments. Apparently, they possess the hardness, impact strength, and tensile strength of the polyamide hard segments, as well as the tensile elongation at break and resilience of the polyether / polyester soft segments. Because of their excellent range of mechanical properties, they are currently widely used in automotive sealing, high-end sports equipment, and electronic folding screen hinges.

[0003] Currently, there are many types of TPAEs on the market. Most of them involve a condensation reaction of pre-prepared polyamide hard segments and polyether / polyester soft segments at high temperatures. The macroscopic mechanical properties of the final product are adjusted by controlling and regulating the hardness and the molecular weight and ratio of the soft segments. For example, patent CN119119489A discloses a polyamide elastomer prepared by reacting hard segment raw materials and soft segment raw materials. The hydroxyl value of the soft segment raw material is 30–600 mg KOH / g; the molar ratio of hard segments to soft segments in this polyamide elastomer is (2–3):(2–3); the number average molecular weight of the hard segments is 1000–3000; and the mass ratio of the hard segments to the soft segments is… The ratio is (1-3):1; Patent CN115850693A discloses a polyether-type polyamide elastomer, which is a block copolymer formed by 10-80 parts by weight of polyamide hard segments, 20-100 parts by weight of soft segments, and 0.5-25 parts by weight of polyolefin liquid rubber; the soft segments include 5-95 wt% of modified polyether polyol, which is selected from vinyl polymer grafted modified polyether polyol and / or polyurea polyol; the polyolefin liquid rubber is selected from one or more of hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, hydroxyl-terminated polybutadiene acrylonitrile liquid rubber, carboxyl-terminated polybutadiene acrylonitrile liquid rubber, and carboxyl-terminated polybutadiene acrylonitrile liquid rubber.

[0004] However, in practical applications, the macroscopic mechanical properties of polyamide elastomers are directly related to the hardness, molecular weight, and proportion of their specific components. Therefore, increasing the proportion / molecular weight of soft segments to improve the soft-segment-dominant mechanical properties will inevitably reduce the proportion of hardness in TPAE (polyamide-based elastomers), thus reducing the hard-segment-dominant mechanical properties, and vice versa. With the rapid development of my country's economy and materials science, it is crucial to invent a novel polyamide elastomer that can improve the soft-segment-dominant mechanical properties without compromising the hard-segment-dominant properties. This would be particularly important for applications in high-end sealing, high-end motion, and consumer electronics. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention discloses a polyamide elastomer and its preparation method. This method can improve the material mechanical properties dominated by the soft segments without sacrificing the hard segment-dominant properties of the polyamide elastomer, resulting in a polyamide elastomer product with excellent overall performance.

[0006] To achieve the above technical objectives, this invention provides a method for preparing a polyamide elastomer, which includes the following steps: (1) Under the action of the first catalyst, the polydiol compound and the diacid monomer undergo a polycondensation reaction in a solvent to obtain the end-capping agent; (2) Under the action of the second catalyst, the end-capping agent reacts with the comonomer to obtain polyamide blocks; (3) In the presence of a stabilizer and under the action of a third catalyst, the soft segment is reacted with the polyamide block to obtain the polyamide elastomer; Wherein, the polydiol compound is a polyalkylene ether diol with a number average molecular weight of 150-2000, and the stoichiometric ratio of the polydiol compound to the diacid monomer is 1:(2.0-2.4); the comonomer is C4-C6. 12 Lactams and / or C4~C 12 Aminocarboxylic acid; the soft segment is a hydroxyl-terminated diol polymer.

[0007] The above technical solution uses a specific polydiol compound and a diacid monomer to condense and obtain a functional end-capping agent with soft segment properties. This end-capping agent has a specific "linear diacid-polyether diol-polyamide-polyether diol-linear diacid" symmetrical structure. By introducing this end-capping agent into the hard segment of polyamide and controlling the proportion of the end-capping agent in the hard segment of polyamide, the material mechanical properties dominated by the soft segment in the polyamide block can be enhanced. Subsequently, the polyamide block and the soft segment are used to carry out a condensation reaction, which can improve the material mechanical properties dominated by the soft segment in the overall polyamide elastomer without causing the loss of the material properties dominated by the hard segment.

[0008] In a further example of the present invention, the types of the polydiol compound were explored and optimized. Optionally, the polydiol compound is a C2-C4 polyalkylene ether glycol with a number average molecular weight of 150-2000. More preferably, the polydiol compound is selected from one or more of polyethylene glycol, poly1,3-propanediol, and poly1,4-butanediol, and its number average molecular weight is 200-800. In an optional example of the present invention, the polydiol compound is one or more of polyethylene glycol with a molecular weight of 200, polyethylene glycol with a molecular weight of 400, polyethylene glycol with a molecular weight of 600, poly1,3-propanediol with a molecular weight of 600, poly1,4-butanediol with a molecular weight of 600, polyethylene glycol with a molecular weight of 800, poly1,3-propanediol with a molecular weight of 800, and poly1,4-butanediol with a molecular weight of 800.

[0009] In a further example of the present invention, the molar ratio of the polydiol compound to the diacid monomer is 1:(1.5~3). The embodiments of the present invention illustrate the preparation process of polyamide elastomers with different stoichiometric ratios of the polydiol compound to the diacid monomer. In an optional example of the present invention, the stoichiometric ratio of the polydiol compound to the diacid monomer is 1:(2.0~2.4).

[0010] In a further example of the present invention, the dicarboxylic acid monomer is an aliphatic dicarboxylic acid with 4-12 carbon atoms. In an optional example of the present invention, the dicarboxylic acid monomer is selected from one or more of succinic acid, adipic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, and dodecanoic acid.

[0011] In a further example of the present invention, the polycondensation reaction is carried out at a temperature of 80-150°C for a time of 6-12 hours.

[0012] In a further example of the invention, the type and amount of the first catalyst were explored. Optionally, the first catalyst is selected from one or more of p-toluenesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, and camphorsulfonic acid. Optionally, the amount of the first catalyst is 0.01% to 0.5% of the total mass of the polydiol compound and the diacid monomer.

[0013] In a further example of the invention, the type and amount of the solvent were explored. Optionally, the solvent is selected from one or more of ethanol, isopropanol, glycerol, ethylene glycol, n-butanol, tetrahydrofuran, dimethyl sulfoxide, N-methylpyrrolidone, and 1,4-dioxane. Optionally, the amount of the solvent is 400% to 900% of the total mass of the polydiol compound and the diacid monomer.

[0014] In a further example of the present invention, step (1) further includes filtering, washing with water, and vacuum drying the reacted material for later use.

[0015] In a further example of the invention, the molecular weight MH of the polyamide block satisfies formula (A): Formula (A); Wherein, ni is the stoichiometric ratio of the amount of the i-th component in the comonomer to the amount of the capping agent; MFi is the molecular weight of the i-th component in the comonomer; MA is the molecular weight of the polydiol; and MB is the molecular weight of the diacid monomer. In formula (A), i is an integer greater than or equal to 1; formula (A) is applicable to the preparation of the polyamide block using one or more comonomers.

[0016] In an optional example of the present invention, the molecular weight MH of the polyamide block is 1000~5000.

[0017] In a further example of the invention, the types of comonomers were explored. Optionally, the comonomers are selected from one or more of butyrolactam, caprolactam, dodecanolactam, 4-aminobutyric acid, 6-aminohexanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

[0018] In a further example of the invention, the type and amount of the first catalyst were explored. Optionally, the second catalyst is selected from one or more of formic acid, acetic acid, propionic acid, hydrochloric acid, sulfuric acid, and phosphoric acid. Optionally, the amount of the second catalyst is 0.01% to 0.1% of the total mass of the capping agent and the comonomer.

[0019] In a further example of the present invention, the contact reaction in step (2) includes: firstly, reacting the reaction system at 180~250℃ and 0.5~5.0MPaG for 6~12h; then depressurizing the reaction system to atmospheric pressure within 0.5~4.0h; and then reacting at 500Pa(A) to 101.325kPa(A) for 0.5~4.0h. In an optional example of the present invention, step (2) further includes cooling, separating, and drying the material after the reaction to obtain the polyamide block.

[0020] In a further example of the present invention, in step (3), the molar ratio of the polyamide block to the soft segment is (0.9~1.1):1, thereby achieving the improvement of the material mechanical properties dominated by the soft segment without causing the loss of the material properties dominated by the hard segment by adjusting the polyamide, functional end-capping agent and the ratio of hard segment to soft segment in the hard segment.

[0021] In a further example of the invention, the types of the soft segment were explored. Optionally, the soft segment is one or more of polyether glycol, polycarbonate glycol, or their co-ether glycols; further optionally, the number average molecular weight of the soft segment is 1000-5000; in an optional example of the invention, the soft segment is selected from one or more of polyethylene oxide glycol, polypropylene oxide glycol, polytetrahydrofuran glycol, polycarbonate glycol, ethylene oxide-propylene oxide copolyol, and ethylene oxide-tetrahydrofuran copolyol.

[0022] In a further example of the present invention, the contact reaction in step (3) includes: first reacting at 180~250°C and 500PaA to 101.325kPaA for 0.5~4h; then holding at 500Pa(A) to 101.325kPa(A) for 0.5~4h.

[0023] In a further example of the present invention, step (3) further includes cooling, pelletizing and drying the reacted material to obtain a polyamide elastomer product.

[0024] In a further example of the invention, the type and amount of the stabilizer are explored and optimized. Optionally, the stabilizer is selected from one or more of antioxidants and / or light stabilizers; more preferably, the stabilizer is selected from one or more of antioxidant 1098, antioxidant 168, antioxidant 1010, antioxidant 1076, light stabilizer 770DF, light stabilizer MiraclePlastic 81, and light stabilizer VSU. Optionally, the amount of the stabilizer is 0.01% to 1% of the total mass of the polyamide block and the soft segment.

[0025] In a further example of the invention, the type and amount of the third catalyst were explored. Optionally, the third catalyst is selected from one or more of zirconium-based, germanium-based, or titanium-based catalysts; more preferably, the third catalyst is selected from one or more of tetraethyltitanium, tetrabutyl titanate, tetrapropyl zirconate, tetrabutyl zirconate, and germanium glycol. Optionally, the amount of the third catalyst is 0.01% to 1% of the total mass of the polyamide block and the soft segment.

[0026] On the other hand, this invention proposes a polyamide elastomer, which is prepared using the above-described method for preparing polyamide elastomers. Examples of this invention demonstrate that the polyamide elastomer prepared using the method of this invention exhibits a tensile elongation at break >650%, a tensile strength at break >50 MPa, and a Shore hardness D ≥50, demonstrating excellent overall performance.

[0027] Compared with existing technologies, the advantages of this invention are as follows: By introducing a specific functional end-capping agent with soft-segment properties into the hard segments of polyamide and controlling the proportion of the end-capping agent in the hard segments, and then conducting a condensation reaction with the soft segments, this invention can improve the soft-segment-dominated mechanical properties of the polyamide elastomer without causing a loss of the hard-segment-dominated material properties. Furthermore, the overall preparation method of this invention is simple to operate and can be run on existing elastomer preparation equipment, greatly reducing the equipment and time costs for industrialization and possessing outstanding prospects for industrial application. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The images show the morphology of the polyamide elastomers prepared in Examples 1-4, Comparative Example 1, and Comparative Example 2 before and after tensile fracture tests. Detailed Implementation

[0029] To facilitate understanding of the present invention, a more comprehensive description will be provided below, along with preferred embodiments. However, it should be understood that these embodiments are merely for more detailed explanation and should not be construed as limiting the invention in any way, i.e., not intended to limit the scope of protection of the invention.

[0030] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0031] Furthermore, it should be noted that although the various steps of the preparation method of the present invention are described in a specific order in the description of the present invention, these orders are not restrictive. Without departing from the basic principles of the present invention, those skilled in the art can perform the steps in different orders.

[0032] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" or "at least one" means two or more.

[0033] All numerical designations, such as temperature, pressure, time, and ranges, are approximate values. It should be understood that, while not always explicitly stated, all numerical designations are preceded by the term "approximately." It should also be understood that, while not always explicitly stated, the reagents described herein are merely examples, and their equivalents are known in the art.

[0034] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0035] The testing methods involved in the embodiments and comparative examples of this invention are as follows: (1) Weight average molecular weight and molecular weight distribution: determined by gel permeation chromatography (GPC).

[0036] (2) Tensile breaking strength and tensile breaking elongation: measured by ISO 527-1.

[0037] (3) Shore hardness D: measured by ISO 868.

[0038] Example 1

[0039] A method for preparing a polyamide elastomer, specifically: (1) Weigh 200g of polyethylene glycol with a molecular weight of 200, 292.28g of adipic acid, 4430.52g of tetrahydrofuran and 2.46g of p-toluenesulfonic acid, and add them sequentially into the reaction vessel. Under nitrogen protection, raise the temperature to 150℃ and keep the reaction at this temperature for 6 hours. After the reaction is completed, cool the product and release it. After filtration, washing with water and vacuum drying, it is used as a capping agent for later use (the molecular weight of the capping agent is calculated to be 492.28 based on the molar ratio).

[0040] (2) Subsequently, 253.86 g of caprolactam, 246.14 g of end-capping agent and 0.5 g of acetic acid were weighed and added to the reactor. The temperature was raised to 250 °C under nitrogen protection, and the ring-opening reaction was carried out at this temperature with nitrogen pressure to 5.0 MPaG for 6 hours. After the reaction, the pressure in the reaction system was gradually reduced to atmospheric pressure over 4 hours, and the pressure in the reaction system was reduced to 500 PaA using a vacuum pump. The reaction was continued at 250 °C for 0.5 hours. After the reaction, the product was discharged into cold water through the bottom outlet of the reactor. After cooling, filtration, water washing and vacuum drying, it was used as a polyamide block for later use (the molecular weight of the polyamide block was calculated to be 1000 according to the stoichiometric ratio and formula (A).

[0041] (3) Weigh 400g of polyamide block, 363g of polypropylene glycol with a molecular weight of 2000, 7.63g of tetrabutyl titanate, 3.82g of antioxidant 168 and 3.82g of UV stabilizer VSU and add them to the reactor. Under nitrogen protection and normal pressure, the temperature is raised to 250℃ and maintained at this temperature for 0.5 hours. Then, the pressure in the reaction system is reduced to 500PaA using a vacuum pump, and the reaction continues at 250℃ for 0.5 hours. After the reaction is completed, the product is discharged into cold water through the bottom outlet of the reactor. After cooling, pelletizing and vacuum drying, the final product is obtained.

[0042] The polyamide elastomer prepared in this embodiment has a final weight-average molecular weight of 56,000, a molecular weight distribution of 2.6, a tensile elongation at break of 657%, a tensile strength at break of 54 MPa, and a Shore hardness of 52D.

[0043] Example 2

[0044] A method for preparing a polyamide elastomer, specifically: (1) Weigh 600 g of poly(1,3-propanediol) with a molecular weight of 600, 552 g of dodecanoic acid, 4608 g of n-butanol and 0.12 g of trifluoromethanesulfonic acid, and add them sequentially into the reaction vessel. Under nitrogen protection, raise the temperature to 80°C and keep the reaction at this temperature for 12 hours. After the reaction is completed, cool the product and release it. After filtration, washing with water and vacuum drying, it is used as a capping agent for later use (the molecular weight of the capping agent is 1060).

[0045] (2) Subsequently, 394 g of dodecyl lactam, 106 g of end-capping agent, and 0.05 g of phosphoric acid were weighed and added to the reactor. Under nitrogen protection, the temperature was raised to 180°C, and the ring-opening reaction was carried out at this temperature by pressurizing with nitrogen to 0.5 MPaG for 12 hours. After the reaction, the pressure in the reaction system was gradually reduced to atmospheric pressure over 0.5 hours, and the pressure in the reaction system was reduced to 5000 PaA using a vacuum pump. The reaction was continued at 180°C for 2 hours. After the reaction, the product was discharged into cold water through the bottom outlet of the reactor. After cooling, filtration, water washing, and vacuum drying, it was used as a polyamide block for later use (the molecular weight of the polyamide block was 5000).

[0046] (3) Weigh 400 g of polyamide block, 440 g of polytetrahydrofuran glycol with a molecular weight of 5000, 0.084 g of germanium glycol, 0.042 g of antioxidant 1098 and 0.042 g of light stabilizer DF770 and add them to the reactor. Under normal pressure and nitrogen protection, the temperature is raised to 180°C and maintained at this temperature for 4 hours. Then, the pressure in the reaction system is reduced to 5000 PaA using a vacuum pump, and the reaction continues at 180°C for 2 hours. After the reaction is completed, the product is discharged into cold water through the bottom outlet of the reactor. After cooling, pelletizing and vacuum drying, the final product is obtained.

[0047] The polyamide elastomer prepared in this embodiment has a final weight-average molecular weight of 51,000, a molecular weight distribution of 2.4, a tensile elongation at break of 655%, a tensile strength at break of 52 MPa, and a Shore hardness of 51D.

[0048] Example 3

[0049] A method for preparing a polyamide elastomer, specifically: (1) Weigh 800 g of poly(1,4-butanediol) with a molecular weight of 800, 404.5 g of sebacic acid, 4818 g of N-methylpyrrolidone and 1.2 g of benzenesulfonic acid, and add them sequentially into the reaction vessel. Under nitrogen protection, raise the temperature to 120°C and keep the reaction at this temperature for 8 hours. After the reaction is completed, cool the product and release it. After filtration, washing with water and vacuum drying, it is used as a capping agent for later use (the molecular weight of the capping agent is 1204.5).

[0050] (2) Subsequently, 398 g of 12-aminododecanoic acid, 602 g of end-capping agent and 0.1 g of propionic acid were weighed and added to the reactor. The temperature was raised to 220°C under nitrogen protection, and the ring-opening reaction was carried out at this temperature by pressurizing with nitrogen to 3 MPaG for 10 hours. After the reaction was completed, the pressure in the reaction system was gradually reduced to atmospheric pressure over 2 hours, and the reaction was continued at 220°C for 4 hours. After the reaction was completed, the product was discharged into cold water through the bottom outlet of the reactor. After cooling, filtration, water washing and vacuum drying, it was used as a polyamide block for later use (the molecular weight of the polyamide block was 2000).

[0051] (3) Weigh 500 g of polyamide block copolymer, 250 g of ethylene oxide-propylene oxide copolymer with a molecular weight of 1000, 4 g of tetrabutyl zirconate, 2 g of antioxidant 1010 and 1 g of light stabilizer Qimiaosu 81 and add them to the reactor. Under normal pressure and nitrogen protection, heat to 220°C and keep at this temperature for 4 hours. After the reaction is completed, discharge the product into cold water through the discharge port at the bottom of the reactor. After cooling, pelletizing and vacuum drying, the final product is obtained.

[0052] The polyamide elastomer prepared in this embodiment has a final weight-average molecular weight of 46,000, a molecular weight distribution of 2.6, a tensile elongation at break of 658%, a tensile strength at break of 53 MPa, and a Shore hardness of 52D.

[0053] Example 4

[0054] A method for preparing a polyamide elastomer, specifically: (1) Weigh 600 g of polyethylene glycol with a molecular weight of 600, 292.28 g of adipic acid, 3600 g of dimethyl sulfoxide and 4 g of p-toluenesulfonic acid, and add them sequentially into the reaction vessel. Under nitrogen protection, raise the temperature to 120°C and keep the reaction at this temperature for 10 hours. After the reaction is completed, cool the product and release it. After filtration, washing with water and vacuum drying, it is used as a capping agent for later use (the molecular weight of the capping agent is 892.28).

[0055] (2) Subsequently, 553.86 g of dodecyl lactam, 446.14 g of end-capping agent and 0.5 g of sulfuric acid were weighed and added to the reactor. Under nitrogen protection, the temperature was raised to 220°C, and the ring-opening reaction was carried out at this temperature by pressurizing with nitrogen to 2 MPaG for 10 hours. After the reaction, the pressure in the reaction system was gradually reduced to atmospheric pressure over 2 hours, and the pressure in the reaction system was reduced to 1000 PaA using a vacuum pump. The reaction was continued at 220°C for 2 hours. After the reaction, the product was discharged into cold water through the bottom outlet of the reactor. After cooling, filtration, water washing and vacuum drying, it was used as a polyamide block for later use (the molecular weight of the polyamide block was 2000).

[0056] (3) Weigh 500 g of polyamide block copolymer, 500 g of ethylene oxide-tetrahydrofuran copolymer with a molecular weight of 2000, 5 g of tetraethylgermanium, 2 g of antioxidant 1098 and 3 g of light stabilizer DF770 and add them to the reactor. Under normal pressure and nitrogen protection, the temperature is raised to 220°C and maintained at this temperature for 2 hours. Then, the pressure in the reaction system is reduced to 1000 PaA using a vacuum pump, and the reaction is continued to be maintained at this temperature for 1 hour. After the reaction is completed, the product is discharged into cold water through the discharge port at the bottom of the reactor. After cooling, pelletizing and vacuum drying, the final product is obtained.

[0057] The polyamide elastomer prepared in this embodiment has a final weight-average molecular weight of 53,000, a molecular weight distribution of 2.3, a tensile elongation at break of 662%, a tensile strength at break of 51 MPa, and a Shore hardness of 51D.

[0058] Example 5

[0059] A method for preparing a polyamide elastomer, specifically: (1) Weigh 600 g of polyethylene glycol with a molecular weight of 600, 292.28 g of adipic acid, 3600 g of dimethyl sulfoxide, 2 g of p-toluenesulfonic acid and 2 g of benzenesulfonic acid, and add them sequentially into the reaction vessel. Under nitrogen protection, raise the temperature to 120°C and keep the reaction at this temperature for 10 hours. After the reaction is completed, cool the product and release it. After filtration, washing with water and vacuum drying, it is used as a capping agent for later use (the molecular weight of the capping agent is 892.28).

[0060] (2) Subsequently, 450 g of dodecanoic acid, 103.86 g of dodecanoic acid, 446.14 g of end-capping agent, 0.4 g of sulfuric acid and 0.1 g of acetic acid were weighed and added to the reactor. The mixture was heated to 220°C under nitrogen protection and pressurized to 2 MPaG at this temperature for 10 hours to carry out the ring-opening reaction. After the reaction was completed, the pressure in the reaction system was gradually reduced to atmospheric pressure over 2 hours, and the pressure in the reaction system was reduced to 1000 PaA using a vacuum pump. The reaction was then continued at 220°C for 2 hours. After the reaction was completed, the product was discharged into cold water through the bottom outlet of the reactor. After cooling, filtration, washing with water and vacuum drying, it was used as a polyamide block for later use (the molecular weight of the polyamide block was 2000).

[0061] (3) Weigh 500 g of polyamide block copolymer, 500 g of ethylene oxide-tetrahydrofuran copolymer with a molecular weight of 2000, 5 g of tetraethylgermanium, 2 g of antioxidant 1098 and 3 g of light stabilizer DF770 and add them to the reactor. Under normal pressure and nitrogen protection, the temperature is raised to 220°C and maintained at this temperature for 2 hours. Then, the pressure in the reaction system is reduced to 1000 PaA using a vacuum pump, and the reaction is continued to be maintained at this temperature for 1 hour. After the reaction is completed, the product is discharged into cold water through the discharge port at the bottom of the reactor. After cooling, pelletizing and vacuum drying, the final product is obtained.

[0062] The polyamide elastomer prepared in this embodiment has a final weight-average molecular weight of 52,000, a molecular weight distribution of 2.4, a tensile elongation at break of 673%, a tensile strength at break of 52 MPa, and a Shore hardness of 50D.

[0063] Example 6

[0064] A method for preparing a polyamide elastomer, specifically: (1) Weigh 600 g of polyethylene glycol with a molecular weight of 600, 146.14 g of adipic acid, 174.19 g of octanoic acid, 3600 g of dimethyl sulfoxide and 4 g of p-toluenesulfonic acid, and add them sequentially into the reaction vessel. Under nitrogen protection, raise the temperature to 120°C and keep the reaction at this temperature for 10 hours. After the reaction is completed, cool the product and release it. After filtration, washing with water and vacuum drying, it is used as a capping agent for later use (the molecular weight of the capping agent is 920.33).

[0065] (2) Subsequently, 539.84 g of dodecyl lactam, 460.16 g of end-capping agent and 0.5 g of sulfuric acid were weighed and added to the reactor. The temperature was raised to 220°C under nitrogen protection, and the ring-opening reaction was carried out at this temperature by pressurizing with nitrogen to 2 MPaG for 10 hours. After the reaction was completed, the pressure in the reaction system was gradually reduced to atmospheric pressure over 2 hours, and the pressure in the reaction system was reduced to 1000 PaA using a vacuum pump. The reaction was continued at 220°C for 2 hours. After the reaction was completed, the product was discharged into cold water through the bottom outlet of the reactor. After cooling, filtration, water washing and vacuum drying, it was used as a polyamide block for later use (the molecular weight of the polyamide block was 2000).

[0066] (3) Weigh 500 g of polyamide block copolymer, 350 g of ethylene oxide-tetrahydrofuran copolymer with a molecular weight of 2000, 150 g of polycarbonate glycol with a molecular weight of 2000, 4 g of tetraethylgermanium, 1 g of ethylene glycol germanium, 2 g of antioxidant 1098 and 3 g of light stabilizer DF770 and add them to the reactor. Under normal pressure and nitrogen protection, the temperature is raised to 220°C and maintained at this temperature for 2 hours. Then, the pressure in the reaction system is reduced to 1000 PaA using a vacuum pump, and the reaction is continued to be maintained at this temperature for 1 hour. After the reaction is completed, the product is discharged into cold water through the discharge port at the bottom of the reactor. After cooling, pelletizing and vacuum drying, the final product is obtained.

[0067] The polyamide elastomer prepared in this embodiment has a final weight-average molecular weight of 51,000, a molecular weight distribution of 2.4, a tensile elongation at break of 658%, a tensile strength at break of 50 MPa, and a Shore hardness of 50D.

[0068] Comparative Example 1 Compared to Example 4, this comparative example uses adipic acid as a capping agent in the preparation of polyamide elastomers, specifically: (1) Weigh 553.86 g of dodecyl lactam, 43.66 g of adipic acid as a capping agent, and 0.3 g of sulfuric acid and add them to the reactor. Under nitrogen protection, heat the reactor to 220°C and pressurize it to 2 MPaG at this temperature for 10 hours to carry out the ring-opening reaction. After the reaction, gradually reduce the pressure in the reaction system to atmospheric pressure over 2 hours, and use a vacuum pump to reduce the pressure in the reaction system to 1000 PaA, and continue to keep the reaction at this temperature for 2 hours. After the reaction, discharge the product into cold water through the bottom outlet of the reactor. After cooling, filtering, washing with water, and vacuum drying, the product is used as a polyamide block for later use (the molecular weight of the polyamide block is calculated to be 2000 according to the stoichiometric ratio and formula (A)).

[0069] (2) Weigh 500 g of polyamide block copolymer, 500 g of ethylene oxide-tetrahydrofuran copolymer with a molecular weight of 2000, 5 g of tetraethylgermanium, 2 g of antioxidant 1098 and 3 g of light stabilizer DF770 and add them to the reactor. Under normal pressure and nitrogen protection, the temperature is raised to 220°C and maintained at this temperature for 2 hours. Then, the pressure in the reaction system is reduced to 1000 PaA using a vacuum pump, and the reaction is continued to be maintained at this temperature for 1 hour. After the reaction is completed, the product is discharged into cold water through the discharge port at the bottom of the reactor. After cooling, pelletizing and vacuum drying, the final product is obtained.

[0070] The polyamide elastomer prepared in this comparative example has a final weight-average molecular weight of 53,000, a molecular weight distribution of 2.4, a tensile elongation at break of 383%, a tensile strength at break of 51 MPa, and a Shore hardness of 50D.

[0071] Combining Example 4 and Comparative Example 1, the Shore hardness of the two hard segments differs by only 1D, their tensile strength at break is the same, and their weight-average molecular weight / distribution is not significantly different. This shows that using different end-capping agents has little impact on the performance of the hard segment phase. However, compared with Comparative Example 1, which uses adipic acid as the end-capping agent, Example 4, which uses a specific end-capping agent, shows a 73% increase in elongation at break and a slightly narrower molecular weight distribution. This confirms that the embodiments of the present invention can obtain a better elongation at break by optimizing the soft segment structure while maintaining the performance of the hard segment phase, thereby improving the performance of the soft segment phase and obtaining a polyamide elastomer product with better overall performance.

[0072] Comparative Example 2 Compared to Example 1, this comparative example increases the amount of dodecyl lactam in step (2) and increases the amount of the polyamide block obtained in step (2) in step (3). Specifically: (1) Weigh 600 g of polyethylene glycol with a molecular weight of 600, 292.28 g of adipic acid, 3600 g of dimethyl sulfoxide and 4 g of p-toluenesulfonic acid, and add them sequentially into the reaction vessel. Under nitrogen protection, raise the temperature to 120°C and keep the reaction at this temperature for 10 hours. After the reaction is completed, cool the product and release it. After filtration, washing with water and vacuum drying, it is used as a capping agent for later use (the molecular weight of the capping agent is 892.28).

[0073] (2) Subsequently, 928.86 g of dodecyl lactam, 446.14 g of end-capping agent and 0.69 g of sulfuric acid were weighed and added to the reactor. The temperature was raised to 220°C under nitrogen protection, and the ring-opening reaction was carried out at this temperature by pressurizing with nitrogen to 2 MPaG for 10 hours. After the reaction was completed, the pressure in the reaction system was gradually reduced to atmospheric pressure over 2 hours, and the pressure in the reaction system was reduced to 1000 PaA using a vacuum pump. The reaction was continued at 220°C for 2 hours. After the reaction was completed, the product was discharged into cold water through the bottom outlet of the reactor. After cooling, filtration, water washing and vacuum drying, it was used as a polyamide block for later use (the molecular weight of the polyamide block was 2750).

[0074] (3) Weigh 687.5 g of polyamide block, 500 g of ethylene oxide-tetrahydrofuran copolymer with a molecular weight of 2000, 9.38 g of tetraethylgermanium, 3.75 g of antioxidant 1098 and 5.63 g of light stabilizer DF770 and add them to the reactor. Under normal pressure and nitrogen protection, the temperature is raised to 220°C and maintained at this temperature for 2 hours. Then, the pressure in the reaction system is reduced to 1000 PaA using a vacuum pump, and the reaction is continued to be maintained at this temperature for 1 hour. After the reaction is completed, the product is discharged into cold water through the discharge port at the bottom of the reactor. After cooling, pelletizing and vacuum drying, the final product is obtained.

[0075] The final weight-average molecular weight of the product obtained in this comparative example is 55,000, the molecular weight distribution is 2.4, the tensile elongation at break is 452%, the tensile strength at break is 65 MPa, and the Shore hardness is 56D.

[0076] Combining Example 4 and Comparative Example 2, it can be seen that the Shore hardness of Comparative Example 2, which has a larger hard segment molecular weight, differs from that of Example 4 by 5D, indicating that Comparative Example 2 has a higher Shore hardness and a 27% increase in tensile strength at break. However, the weight-average molecular weight difference between the two is only 2k, confirming that increasing the hard segment molecular weight achieves hard segment phase strengthening. However, the elongation at break of Example 4 is 210% higher than that of Comparative Example 2. Combined with their almost identical molecular weight distribution, this confirms that while the use of a larger molecular weight hard segment in Comparative Example 2 improves the active mechanical properties of the hard segment, it comes at a significant cost in terms of elongation. Example 4 of this invention, by controlling the hard segment molecular weight within a suitable range, can enhance the dominant mechanical properties of the hard segment without affecting the dominant mechanical properties of the soft segment.

[0077] Comparative Example 3 Compared to Example 1, this comparative example reduces the amount of caprolactam in step (2) and reduces the amount of polyamide block obtained in step (2) in step (3). Specifically: (1) Weigh 200 g of polyethylene glycol with a molecular weight of 200, 292.28 g of adipic acid, 4430.52 g of tetrahydrofuran and 2.46 g of p-toluenesulfonic acid, and add them sequentially into the reaction vessel. Under nitrogen protection, raise the temperature to 150°C and keep the reaction at this temperature for 6 hours. After the reaction is completed, cool the product and release it. After filtration, washing with water and vacuum drying, it is used as a capping agent for later use (the molecular weight of the capping agent is 492.28).

[0078] (2) Subsequently, 126.93 g of caprolactam, 246.14 g of end-capping agent, and 0.37 g of acetic acid were weighed and added to the reactor. Under nitrogen protection, the temperature was raised to 250°C, and the ring-opening reaction was carried out at this temperature with nitrogen pressure to 5.0 MPaG for 6 hours. After the reaction, the pressure in the reaction system was gradually reduced to atmospheric pressure over 4 hours, and the pressure in the reaction system was reduced to 500 PaA using a vacuum pump. The reaction was continued at 250°C for 0.5 hours. After the reaction, the product was discharged into cold water through the bottom outlet of the reactor. After cooling, filtration, water washing, and vacuum drying, it was used as a polyamide block for later use (the molecular weight of the polyamide block was 746.14).

[0079] (3) Weigh 298.5 g of polyamide block, 363 g of polypropylene glycol with a molecular weight of 2000, 5.63 g of tetrabutyl titanate, 2.82 g of antioxidant 168 and 2.82 g of UV stabilizer VSU and add them to the reactor. Under normal pressure and nitrogen protection, the temperature is raised to 250°C and maintained at this temperature for 0.5 hours. Then, the pressure in the reaction system is reduced to 500 PaA using a vacuum pump, and the reaction is maintained at 250°C for 0.5 hours. After the reaction is completed, the product is discharged into cold water through the discharge port at the bottom of the reactor. After cooling, pelletizing and vacuum drying, the final product is obtained.

[0080] The final weight-average molecular weight of the product obtained in this comparative example is 51,000, the molecular weight distribution is 2.5, the tensile elongation at break is 558%, the tensile strength at break is 28 MPa, and the Shore hardness is 32D.

[0081] As can be seen from Example 1 / Comparative Example 3, compared to Comparative Example 3 with its smaller hard segment molecular weight, Example 1 controls the molecular weight of the polyamide block (hard segment) within a suitable range, resulting in a 20D increase in Shore hardness and a 93% increase in tensile strength, while maintaining the weight-average molecular weight increase within 10%. This confirms that the present invention can make the hard segment phase more complete and continuous. Furthermore, the elongation at break increases by 99% while the molecular weight distribution remains almost identical, confirming that the chemical structure and chain length of the soft segment are not damaged, and the elastic mechanism is preserved. Therefore, this further confirms that the preparation method of the polyamide elastomer of the present invention can achieve enhanced hard segment performance while maintaining high ductility of the soft segment phase.

[0082] It should be noted that the above description is a further detailed explanation of the present invention in conjunction with specific embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple improvements can be made without departing from the concept of the present invention, and all such improvements should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing a polyamide elastomer, characterized in that, Includes the following steps: (1) Under the action of the first catalyst, the polydiol compound and the diacid monomer undergo a polycondensation reaction in a solvent to obtain the end-capping agent; (2) Under the action of the second catalyst, the end-capping agent reacts with the comonomer to obtain polyamide blocks; (3) In the presence of a stabilizer and under the action of a third catalyst, the soft segment is reacted with the polyamide block to obtain the polyamide elastomer; Wherein, the polydiol compound is a polyalkylene ether diol with a number average molecular weight of 150-2000, and the stoichiometric ratio of the polydiol compound to the diacid monomer is 1:(2.0-2.4); the comonomer is C4-C6. 12 Lactams and / or C4~C 12 Aminocarboxylic acid; the soft segment is a hydroxyl-terminated diol polymer.

2. The method for preparing polyamide elastomer according to claim 1, characterized in that, The polydiol compound is a C2-C4 polyalkylene ether diol with a number average molecular weight of 150-2000; Preferably, the polydiol compound is selected from one or more of polyethylene glycol, poly1,3-propanediol, and poly1,4-butanediol, and its number-average molecular weight is 200 to 800.

3. The method for preparing the polyamide elastomer according to claim 1, characterized in that, The molar ratio of the polydiol compound to the diacid monomer is 1:(1.5~3), preferably 1:(2.0~2.4). And / or, the dicarboxylic acid monomer is an aliphatic dicarboxylic acid with 4-12 carbon atoms; preferably, the dicarboxylic acid monomer is selected from one or more of succinic acid, adipic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, and dodecanoic acid. And / or, the polycondensation reaction is carried out at a temperature of 80~150℃ for a time of 6~12h.

4. The method for preparing the polyamide elastomer according to claim 1, characterized in that, The first catalyst is selected from one or more of p-toluenesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, and camphorsulfonic acid; And / or, the amount of the first catalyst is 0.01% to 0.5% of the total mass of the polydiol compound and the diacid monomer; And / or, the solvent is selected from one or more of ethanol, isopropanol, glycerol, ethylene glycol, n-butanol, tetrahydrofuran, dimethyl sulfoxide, N-methylpyrrolidone, and 1,4-dioxane; And / or, the amount of solvent used is 400% to 900% of the total mass of the polydiol compound and the diacid monomer.

5. The method for preparing the polyamide elastomer according to claim 1, characterized in that, The molecular weight MH of the polyamide block satisfies formula (A): Formula (A); Wherein, ni is the stoichiometric ratio of the amount of the i-th component in the comonomer to the amount of the capping agent; MFi is the molecular weight of the i-th component in the comonomer; MA is the molecular weight of the polydiol; MB is the molecular weight of the diacid monomer; and i is an integer greater than or equal to 1. Preferably, the molecular weight (MH) of the polyamide block is 1000~5000.

6. The method for preparing the polyamide elastomer according to claim 1, characterized in that, The comonomer is selected from one or more of butyrolactam, caprolactam, dodecanoic acid, 4-aminobutyric acid, 6-aminohexanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid. And / or, the second catalyst is selected from one or more of formic acid, acetic acid, propionic acid, hydrochloric acid, sulfuric acid, and phosphoric acid; And / or, the amount of the second catalyst is 0.01% to 0.1% of the total mass of the capping agent and the comonomer.

7. The method for preparing the polyamide elastomer according to claim 1, characterized in that, The contact reaction in step (2) includes: first, reacting the reaction system at 180~250℃ and 0.5~5.0MPaG for 6~12h; then depressurizing the reaction system to atmospheric pressure within 0.5~4.0h; and then reacting it at 500PaA to 101.325kPaA for 0.5~4.0h. Preferably, step (2) further includes cooling, separating and drying the material after the reaction is completed to obtain the polyamide block.

8. The method for preparing the polyamide elastomer according to claim 1, characterized in that, In step (3), the molar ratio of the polyamide block to the soft segment is (0.9~1.1):1; And / or, the soft segment is one or more of polyether glycol, polycarbonate glycol or its co-ether glycol; Preferably, the number-average molecular weight of the soft segment is 1000~5000; More preferably, the soft segment is selected from one or more of polyethylene oxide glycol, polyethylene oxide glycol, polytetrahydrofuran glycol, polycarbonate glycol, ethylene oxide-propylene oxide copolymer glycol, and ethylene oxide-tetrahydrofuran copolymer glycol; And / or, the contact reaction in step (3) includes: first reacting at 180~250℃ and 500PaA to 101.325kPaA for 0.5~4h; then holding at 500Pa(A) to 101.325kPa(A) for 0.5~4h; Preferably, step (3) further includes cooling, pelletizing and drying the reacted material to obtain a polyamide elastomer product.

9. The method for preparing the polyamide elastomer according to claim 1, characterized in that, The stabilizer is selected from one or more antioxidants and / or light stabilizers; Preferably, the stabilizer is selected from one or more of antioxidant 1098, antioxidant 168, antioxidant 1010, antioxidant 1076, light stabilizer 770DF, light stabilizer MiraclePlastic 81, and light stabilizer VSU; And / or, the amount of the stabilizer is 0.01% to 1% of the total mass of the polyamide block and the soft segment; And / or, the third catalyst is selected from one or more zirconium-based, germanium-based, or titanium-based catalysts; Preferably, the third catalyst is selected from one or more of tetraethyltitanium, tetrabutyl titanate, tetrapropyl zirconate, tetrabutyl zirconate, and germanium glycol. And / or, the amount of the third catalyst is 0.01% to 1% of the total mass of the polyamide block and the soft segment.

10. A polyamide elastomer, characterized in that, It is prepared by the method of any one of claims 1 to 9 for the preparation of polyamide elastomer.

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