One-step prepared bio-based nylon 12 elastomer and its preparation method and application

Abstract

The present application discloses a one-step preparation of a bio-based nylon 12 elastomer, its preparation method, and application, belonging to the technical field of polyamide materials. The method comprises the following steps: (1) preparing materials: mixing bio-based 12-aminododecanoic acid, polyetheramine, reaction aid, and water in a preparation tank, heating and stirring them uniformly to form a mixture; (2) feeding: pressing the mixture into a polymerization kettle by nitrogen pressurization; and (3) polymerizing. The present application optimizes the raw material combination and polymerization process path to achieve a one-step polymerization reaction (i.e., in the same polymerization kettle) based on bio-based 12-aminododecanoic acid monomers to construct a polyether block amide nylon 12 elastomer. This not only improves the elongation at break and the rebound performance, but also achieves a stable polymerization process, controllable product quality, and good elasticity and processability. The elastomer is suitable for the fields of shoe soles, sealing strips, soft devices, etc.

Description

Technical Field

[0001] The present application relates to a bio-based nylon 12 elastomer prepared in one step, a preparation method thereof, and an application thereof, and belongs to the technical field of polyamide materials. Background Art

[0002] Nylon elastomers are a class of polymer materials that combine rigid amide segments with flexible segments, exhibiting excellent tensile properties, flexibility, and wear resistance. They combine the mechanical strength and thermal stability of nylon with the elasticity and resilience of rubber-like materials. In recent years, they have seen rapid development in the areas of soft-hard composites and green rubber alternatives. Nylon elastomers, represented by polyether block amide (PEBA), exhibit excellent low-temperature toughness, good chemical stability, and processability.

[0003] However, existing PEBA materials are mostly prepared using petroleum-based monomers (such as petroleum-based 12-aminododecanoic acid), making them difficult to meet the trend of green, low-carbon, and sustainable development. Furthermore, traditional processes generally employ blending, melt extrusion, or multi-step polymerization routes. These multi-step polymerization processes are lengthy, energy-intensive, and complex to control. Furthermore, the final product's molecular structure can be irregular, leading to fluctuations in mechanical properties. Chinese patent CN 115785657B discloses a nylon 12 elastomer material, preparation method, and application. This approach utilizes a melt extrusion method for mixing with a toughening agent, a hyperbranched resin, and an alkylbenzenesulfonic acid to produce a nylon 12 elastomer with excellent impact and explosion resistance. However, this approach still relies on physical blending and does not achieve one-step polymerization at the monomer level. Consequently, the structure lacks block copolymer bonding, and a phase boundary still exists between the flexible and rigid segments, limiting the overall performance of the polymer.

[0004] In addition, there are two significant problems in the polymerization process of nylon elastomers:

[0005] 1. Problems with structural matching and intermolecular forces: The significant difference in polarity between polyamide and polyether segments often leads to poor intersegment compatibility and high interfacial forces, making it difficult to balance the overall tensile properties and elongation at break. Improper structural control can also lead to uneven segment distribution and unstable crystalline and amorphous regions, compromising the material's flexibility, resilience, and molding stability.

[0006] 2. Runaway polymerization: Polyamide monomers such as 12-aminododecanoic acid rapidly enter the polycondensation phase when heated to near their melting point. Improper temperature control or drastic changes in system pressure can easily lead to implosion or depolymerization, resulting in product charring and yellowing, molecular chain breakage, and even coking in the reactor. Furthermore, due to the high viscosity and susceptibility to oxidation of flexible segmented polyetheramines, poor discharge of byproducts and small molecules during the reaction can further affect melt fluidity and molding uniformity, leading to unstable material properties. Summary of the Invention

[0007] In order to solve the above problems, a one-step prepared bio-based nylon 12 elastomer, a preparation method and application thereof are provided. By optimizing the raw material combination and polymerization process path, a fully block structure of flexible segments and rigid segments is formed, and a one-step polymerization reaction based on bio-based 12-aminododecanoic acid monomer is completed (i.e., in the same polymerization reactor) to construct a polyether block amide nylon 12 elastomer. This not only improves the elongation at break and rebound performance, but also achieves a stable polymerization process, controllable product quality, good elasticity and processability, and is suitable for use in soles, sealing strips, soft devices and other fields.

[0008] According to one aspect of the present application, a one-step method for preparing a bio-based nylon 12 elastomer is provided, comprising the following steps:

[0009] (1) Preparation: Bio-based 12-aminododecanoic acid, polyetheramine, reaction aid and water are mixed, heated and stirred uniformly in a preparation tank to form a mixture;

[0010] (2) Feeding: Pressurizing the mixture into the polymerization reactor by nitrogen pressurization;

[0011] (3) Aggregation: The following operations are performed in sequence through the control system:

[0012] i. Temperature and pressure increase: The mixture in the polymerization reactor is heated and pressurized in stages, gradually raising the temperature to 170-185°C and the pressure from 0.5 MPa to 1.3 MPa in stages;

[0013] ii. Constant temperature and pressure: Keep the temperature no higher than 185℃, the pressure stable, and gradually drain the moisture. The temperature of the material will automatically rise after drainage. The material temperature should not exceed 200℃. When the material temperature rises to a certain temperature, the pressure will be reduced in stages, but the pressure must always be maintained at no less than 0.8MPa;

[0014] iii. Temperature increase and pressure reduction: the material temperature is gradually increased, the pressure is reduced to normal pressure, and the material temperature is controlled at 220-240℃;

[0015] iv. Constant temperature and pressure: Keep the temperature constant and purge with nitrogen for 0.5-1h. The initial nitrogen flow rate should be higher than the final flow rate.

[0016] v. Constant temperature vacuum: keep the temperature constant and evacuate to 0.06-0.09 MPa;

[0017] vi. Nitrogen pressurization: The polymer melt is discharged through nitrogen pressurization and then pelletized underwater to obtain bio-based nylon 12 elastomer.

[0018] The reaction aids include interchain compatibility agents, segment regulators, catalysts and antioxidants, and the addition amounts are 1-4%, 3-8%, 0.03-0.05% and 0.1-0.3% of the total raw material mass, respectively.

[0019] Specifically, the polymerization kettle of the present application is equipped with a dedicated feed tank, which can immediately pressurize the mixed and temperature-appropriate raw material suspension into the polymerization kettle in the production state with nitrogen, thereby achieving seamless intermittent polymerization and continuous production. The control system used in step (3) is a DCS control system.

[0020] Optionally, the mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine and water is 1:(0.15-0.35):(0.2-0.5).

[0021] Optionally, in the constant temperature and pressure holding stage of step (3), the polymerization dehydration time is 2-3.5 h, the trigger temperature for staged pressure reduction is 195° C., and the pressure reduction rate is 0.05-0.1 MPa / min.

[0022] Furthermore, the present application uses 12-aminododecanoic acid as the core monomer for a polymerization reaction. During the development of a one-step method for preparing bio-based nylon 12 using 12-aminododecanoic acid as a monomer, the inventors of the present application discovered that there are two core problems in the polymerization process of 12-aminododecanoic acid:

[0023] The first problem is that when the temperature rises to near the melting point, polymerization reaction will occur rapidly. At this time, if the pressure and temperature are not properly controlled, it will cause either explosion or depolymerization, affecting the transparency of the product.

[0024] Therefore, in the second stage of polymerization, that is, the constant temperature and pressure holding stage, the present application first accurately controls the polymerization dehydration temperature to be no higher than 185°C, maintains the pressure stable and controls the drainage time, so that in this stage it is in a solid-liquid coexistence state, the lattice gap is expanded, and the water molecules are efficiently diffused. At the same time, the pressure is controlled to maintain the presence of liquid water to avoid premature vaporization leading to volume expansion and destruction of the material structure. At the same time, due to the enthalpy change of the polycondensation reaction, heat will be released during the water removal process, the material temperature will automatically rise, and melt polymerization will begin. In order to further remove moisture and other impurities to increase viscosity and avoid yellowing, the present application is to limit the temperature to reach the trigger temperature before gradually reducing the pressure, and maintain the minimum pressure at above 0.8MPa. At this time, the melt stability is maintained by high pressure, and the reverse reaction of polycondensation is suppressed, so that the material can be stably polymerized and the water molecules can be fully discharged.

[0025] The second problem, which is also the most significant feature that distinguishes it from other nylons, is that due to its extremely fast polymerization speed, many small molecules do not have time to be discharged from the polymer system. As the viscosity increases in the later stages of polymerization, the discharge becomes slower and slower, ultimately leading to uneven viscosity, too wide a molecular weight distribution, poor mechanical properties, and even inability to properly draw strands and pelletize.

[0026] In this regard, the present application blows in an appropriate amount of nitrogen in the fourth stage of polymerization (constant temperature and normal pressure stage), and controls the initial flow rate of nitrogen to be higher than the final flow rate. The initial high flow rate causes the nitrogen to form turbulence on the surface of the melt, forming a vortex peeling boundary layer, accelerating the removal of free small molecules (water, oligomers, other organic matter, etc.), the mid-term transition flow continuously removes residual substances at the grain boundaries, and the late laminar flow maintains the stability of the material state.

[0027] Optionally, the temperature and pressure raising stage in step (3) adopts three-stage temperature and pressure raising:

[0028] The initial temperature is 110-120°C, the pressure is 0.5-0.6 MPa, and the time is 20-25 minutes;

[0029] The middle stage temperature is 160-170℃, the pressure is 0.7-0.9 MPa, and the time is 30-40 minutes;

[0030] The later temperature is 180-185℃, the pressure is 1.1-1.3 MPa, and the time is 30-60min.

[0031] Furthermore, in order to improve the compatibility between the polyamide segment and the polyether segment and achieve polymerization reaction rate matching between the flexible segment and the rigid main chain, the present application adopts a three-stage temperature and pressure control strategy in the temperature and pressure increase stage. Through the step-by-step temperature and pressure increase method of "low-temperature pre-distribution + medium-temperature synergistic reaction + high-temperature polymerization activation", monomers with obvious structural differences in the system are activated and participate in the reaction in an orderly manner at different stages, thereby constructing a block connection reaction path. The specific settings are as follows:

[0032] In the initial stage, the polyetheramine has a flexible molecular structure, a low boiling point, and high activity, while the 12-aminododecanoic acid has not yet reacted significantly. Lower temperatures and moderate pressures facilitate the full dispersion of the polyetheramine in the system, allowing for a slight pre-reaction or the formation of weak hydrogen-bonded complexes with the interchain compatibilizer, resulting in a preliminary uniform molecular distribution and laying the foundation for subsequent block reactions. This stage also effectively inhibits high-temperature oxidation, volatilization, or migration of the polyetheramine.

[0033] The mid-stage is when the polyetheramine amine activation reaction rate peaks, and the 12-aminododecanoic acid begins to undergo polycondensation. Setting a medium-high temperature and continuously increasing the pressure during this period allows the two main monomers to have similar reactivity, promoting the simultaneous polymerization of the soft and hard segments, creating block copolymers or alternating structures, effectively controlling block length distribution, and improving main chain regularity.

[0034] The later stage is the high-activity zone of the polymerization reaction. The condensation of 12-aminododecanoic acid enters the main reaction stage, and the viscosity of the system begins to increase. High temperature and high pressure can not only accelerate the formation of amide bonds, but also suppress the vaporization of water vapor, laying the temperature and pressure foundation for the subsequent "constant temperature and pressure dehydration", while preventing premature boiling of water vapor to cause melt explosion, coking or chain segment damage.

[0035] Optionally, the interchain compatibility agent is p-hydroxyphenylacetic acid or 3-hydroxypropionic acid; the segment regulator is sebacic acid and / or adipic acid. The segment regulator is sebacic acid and adipic acid in a mass ratio of (2-2.2):1

[0036] Preferably, the segment regulators are sebacic acid and adipic acid in a mass ratio of 2:1.

[0037] Specifically, the addition of an interchain compatibilizer forms stable hydrogen-bonded complexes or intermolecular bridging structures with the amino and hydroxyl groups of polyetheramines, or with the amino and carboxyl groups of bio-based 12-aminododecanoic acid. In the early stages of polymerization, these compounds act as "molecular bridges," enhancing the steric compatibility between the rigid segments (nylon structure) and the flexible segments (polyether segments) of the backbone. Some carboxyl groups also participate in the amide polycondensation reaction, acting as "embedded structure-regulating monomers" to regularize the segment distribution and effectively improve intersegment compatibility. The addition of a segment regulator acts as a molecular weight regulator and end-capping agent during the reaction, regulating the polymerization rate and controlling the backbone sequence length. In the later stages of polymerization, they act as chain terminators, inhibiting unlimited backbone growth and forming uniform-length blocks. Sebacic acid prioritizes flexibility and segment regularity, while adipic acid enhances the microstructure of the crystalline region. The combination of these two compounds synergistically regulates molecular weight distribution and block length uniformity.

[0038] Optionally, the catalyst includes a first catalyst and a second catalyst, and the mass ratio of the first catalyst to the second catalyst is (3-5):1.

[0039] Optionally, the first catalyst is phosphotungstic acid, and the second catalyst is phosphoric acid or sodium phosphite;

[0040] The antioxidant is one or more of antioxidant 1010, antioxidant H10 and antioxidant 1098.

[0041] Specifically, by using phosphotungstic acid as the first catalyst and combining it with the second catalyst, while ensuring the efficiency of the amide condensation reaction, the acidic stability and reaction selectivity of the system are effectively adjusted, taking into account both high catalytic activity and low side reaction risks. It is suitable for elastomer polymerization systems with sensitive flexible chain segment structures. While ensuring the integrity of the polymer chain, it effectively avoids the degradation of the polyether segment and yellowing of the product, thereby improving the structural stability and mechanical properties of the final product.

[0042] Optionally, the temperature in step (1) is 80-100°C and the time is 10-30 min; the nitrogen boost pressure in step (2) is 0.2-0.5 MPa;

[0043] In step (3), the reaction time of the constant temperature and pressure holding stage is 2.5-3.5h; the reaction time of the temperature rising and pressure reducing stage is 1-1.5h; the nitrogen purge flow rate of the constant temperature and normal pressure stage is 0.5-1.5L / min; the reaction time of the constant temperature and vacuum stage is 30-60min; the nitrogen pressurization stage time is 10-15min, and the pressure is 0.3-0.5 MPa.

[0044] Specifically, in the constant temperature and normal pressure stage of step (3), the nitrogen purge includes three gradient stages in sequence: a. 0-20 min, flow rate 1.5 L / min; b. 20-40 min, flow rate 1.0 L / min; c. 40-60 min, flow rate 0.5 L / min.

[0045] According to another aspect of the present application, a bio-based nylon 12 elastomer prepared by the above-mentioned preparation method is also provided, wherein the elongation at break of the bio-based nylon 12 elastomer is not less than 500% and the compression permanent deformation is less than 30%.

[0046] According to another aspect of the present application, an application of bio-based nylon 12 prepared by the above-mentioned preparation method is also provided. The bio-based nylon 12 elastomer can be used for soles, soft structural parts, sports protective gear, automotive sealing strips or medical cushioning materials.

[0047] The beneficial effects of this application include but are not limited to:

[0048] 1. According to the one-step preparation method of the bio-based nylon 12 elastomer disclosed herein, the nylon 12 elastomer is prepared by a one-step polymerization using bio-based 12-aminododecanoic acid as the primary monomer and polyetheramine. A polyether block amide backbone is constructed by introducing a flexible segment structure. Interchain compatibilizers and other reaction aids are used to modulate hydrogen bonding, improve the compatibility of the rigid and flexible segments, enhance the segment synergy, and significantly improve the elongation at break, flexibility, and elastic recovery of the elastomer. The resulting product exhibits an elongation at break exceeding 500%, a compression set below 30%, and excellent mechanical properties.

[0049] 2. The one-step method for preparing bio-based nylon 12 elastomers according to this application utilizes a staged process of increasing temperature and pressure to gradually activate various monomers for polymerization, effectively avoiding the risks of insufficient polyether segment participation, irregular or residual chain segments. Furthermore, a multi-stage nitrogen purge combined with a constant temperature vacuum effectively removes moisture, oligomers, and free amine molecules, ensuring a uniform polymer molecular weight distribution and stable performance.

[0050] 3. The one-step method for preparing bio-based nylon 12 elastomers disclosed herein utilizes phosphotungstic acid as the first catalyst, combined with phosphoric acid or sodium phosphite to form a synergistic catalytic system, resulting in high reaction efficiency, excellent thermal stability, and yellowing inhibition. Furthermore, a specific molecular weight regulator is employed to assist in amide bond formation during the reaction and to achieve end-capping at a later stage, effectively controlling the upper molecular weight limit, limiting chain growth anomalies, and reducing the likelihood of side reactions, thereby improving the consistency and processing performance of the finished product.

[0051] 4. The one-step method for preparing bio-based nylon 12 elastomers according to this application integrates the entire polymerization process into a single polymerization reactor by utilizing a feed tank coupled with a single-reactor, six-stage, full-process control. This enables efficient, one-step, continuous production. Compared to traditional step-by-step polymerization or blending processes, this method offers advantages such as a shorter process, lower energy consumption, and greater batch-to-batch stability, making it suitable for rapid pilot and industrial scale-up. DETAILED DESCRIPTION

[0052] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0053] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. The reagents and raw materials used in the present invention can be purchased through conventional channels. Unless otherwise specified, the reagents and raw materials used in the present invention are used in accordance with conventional methods in the art or in accordance with the product instructions. In addition, any methods and materials similar to or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described in this patent are for illustrative purposes only.

[0054] The bio-based 12-aminododecanoic acid used in this application is a commercially available product derived from plant oils such as castor oil and other biological resources; polyetheramine is a commercially available product, and the models can be D-230, T-403, and M-1000. The commercially available polymerization reactor used in this application has an outer jacket + inner coil dual heating system and is equipped with a reaction preparation tank. Underwater hot cutting granulation can be carried out using conventional means in the existing technology. The water used in the preparation method is high-purity water or desalted water, and normal pressure refers to standard atmospheric pressure. The amount of bio-based 12-aminododecanoic acid used in the examples of this application is 5 kg.

[0055] Example 1 Bio-based nylon 12 elastomer-1#

[0056] The preparation method of bio-based nylon 12 elastomer-1# comprises the following steps:

[0057] (1) Preparation: Bio-based 12-aminododecanoic acid, polyetheramine, reaction aid and water are mixed, heated and stirred uniformly in a preparation tank to form a mixture;

[0058] (2) Feeding: Pressurizing the mixture into the polymerization reactor by nitrogen pressurization;

[0059] (3) Aggregation: The following operations are performed in sequence through the control system:

[0060] i. Temperature and pressure increase: The mixture in the polymerization reactor is heated and pressurized in stages, gradually raising the temperature to 180°C and the pressure from 0.5 MPa to 1.3 MPa in stages;

[0061] ii. Constant temperature and pressure: Keep the temperature no higher than 185℃, the pressure stable, and gradually drain the moisture. The temperature of the material will automatically rise after drainage. The material temperature should not exceed 200℃. When the material temperature rises to a certain temperature, the pressure will be reduced in stages, but the pressure must always be maintained at no less than 0.8MPa;

[0062] iii. Temperature increase and pressure reduction: the material temperature is gradually increased, the pressure is reduced to normal pressure, and the material temperature is controlled at 230°C;

[0063] iv. Constant temperature and pressure: Keep the temperature constant and purge with nitrogen for 1 hour. The initial nitrogen flow rate is higher than the final flow rate.

[0064] v. Constant temperature vacuum: keep the temperature constant and evacuate to 0.06 MPa;

[0065] vi. Nitrogen pressurization: The polymer melt is discharged by nitrogen pressurization and then pelletized underwater to obtain bio-based nylon 12 elastomer 1#;

[0066] The reaction aids include an interchain compatibility agent, a segment regulator, a catalyst, and an antioxidant, with the added amounts being 2%, 5%, 0.04%, and 0.2% of the total raw material mass, respectively. The mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine, and water is 1:0.25:0.2. The interchain compatibility agent is p-hydroxyphenylacetic acid; the segment regulators are sebacic acid and adipic acid in a mass ratio of 2:1. The catalyst includes a first catalyst and a second catalyst, with the mass ratio of the first catalyst to the second catalyst being 4:1. The first catalyst is phosphotungstic acid, and the second catalyst is phosphoric acid. The antioxidant is antioxidant 1010.

[0067] In step (1), the temperature is 90°C, the time is 20 min, and the stirring rate is 100 rpm; in step (2), the nitrogen boost pressure is 0.3 MPa;

[0068] In step (3), the temperature and pressure raising stage adopts three-stage temperature and pressure raising: the initial temperature is 120°C, the pressure is 0.5 MPa, and the time is 20 min; the middle temperature is 160°C, the pressure is 0.8 MPa, and the time is 40 min; the late temperature is 180°C, the pressure is 1.3 MPa, and the time is 50 min.

[0069] In the constant temperature and pressure holding stage of step (3), the polymerization dehydration time is 2.5 h, the trigger temperature for the staged pressure reduction is 195 ° C, the pressure reduction rate is 0.1 MPa / min, and the reaction time of the constant temperature and pressure holding stage is 3 h; the reaction time of the temperature increase and pressure reduction stage is 1.5 h; the nitrogen purge in the constant temperature and normal pressure stage includes three gradient stages in sequence: a. 0-20 min, flow rate 1.5 L / min; b. 20-40 min, flow rate 1.0 L / min; c. 40-60 min, flow rate 0.5 L / min; the reaction time of the constant temperature vacuum stage is 45 min; the nitrogen pressurization stage time is 12 min, and the pressure is 0.4 MPa.

[0070] Example 2 Bio-based nylon 12 elastomer-2#

[0071] The preparation method of bio-based nylon 12 elastomer-2# comprises the following steps:

[0072] (1) Preparation: Bio-based 12-aminododecanoic acid, polyetheramine, reaction aid and water are mixed, heated and stirred uniformly in a preparation tank to form a mixture;

[0073] (2) Feeding: Pressurizing the mixture into the polymerization reactor by nitrogen pressurization;

[0074] (3) Aggregation: The following operations are performed in sequence through the control system:

[0075] i. Temperature and pressure increase: The mixture in the polymerization reactor is heated and pressurized in stages, gradually raising the temperature to 185°C and the pressure from 0.5 MPa to 1.3 MPa in stages;

[0076] ii. Constant temperature and pressure: Keep the temperature no higher than 185℃, the pressure stable, and gradually drain the moisture. The temperature of the material will automatically rise after drainage. The material temperature should not exceed 200℃. When the material temperature rises to a certain temperature, the pressure will be reduced in stages, but the pressure must always be maintained at no less than 0.8MPa;

[0077] iii. Temperature increase and pressure reduction: the material temperature is gradually increased, the pressure is reduced to normal pressure, and the material temperature is controlled at 220℃;

[0078] iv. Constant temperature and pressure: Keep the temperature constant and purge with nitrogen for 1 hour. The initial nitrogen flow rate is higher than the final flow rate.

[0079] v. Constant temperature vacuum: keep the temperature constant and evacuate to 0.09 MPa;

[0080] vi. Nitrogen pressurization: The polymer melt is discharged by nitrogen pressurization and then pelletized underwater to obtain bio-based nylon 12 elastomer 2#;

[0081] The reaction aids include interchain compatibility agent, segment regulator, catalyst and antioxidant, and the addition amounts are 1%, 3%, 0.03% and 0.1% of the total raw material mass, respectively.

[0082] The mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine, and water is 1:0.15:0.25. The interchain compatibility agent is 3-hydroxypropionic acid; the segment regulators are sebacic acid and adipic acid in a mass ratio of 2.2:1. The catalyst includes a first catalyst and a second catalyst, with the mass ratio of the first catalyst to the second catalyst being 3:1. The first catalyst is phosphotungstic acid, and the second catalyst is sodium phosphite. The antioxidant is H10.

[0083] In step (1), the temperature is 80°C and the time is 30 min; in step (2), the nitrogen boost pressure is 0.2 MPa;

[0084] In step (3), the temperature and pressure raising stage adopts three-stage temperature and pressure raising: the initial temperature is 110°C, the pressure is 0.5 MPa, and the time is 25 min; the middle temperature is 170°C, the pressure is 0.8 MPa, and the time is 30 min; the late temperature is 185°C, the pressure is 1.3 MPa, and the time is 50 min.

[0085] In the constant temperature and pressure holding stage of step (3), the polymerization dehydration time is 2 hours, the trigger temperature for the staged pressure reduction is 195°C, the pressure reduction rate is 0.08 MPa / min, and the reaction time in the constant temperature and pressure holding stage is 3 hours; the reaction time in the temperature rising and pressure reducing stage is 1 hour; the nitrogen purge in the constant temperature and normal pressure stage includes three gradient stages in sequence: a. 0-20 minutes, flow rate 1.5 L / min; b. 20-40 minutes, flow rate 1.0 L / min; c. 40-60 minutes, flow rate 0.5 L / min; the reaction time in the constant temperature and vacuum stage is 30 minutes; the nitrogen pressurization stage time is 10 minutes, and the pressure is 0.3 MPa.

[0086] Example 3 Bio-based nylon 12 elastomer-3#

[0087] The preparation method of bio-based nylon 12 elastomer-3# comprises the following steps:

[0088] (1) Preparation: Bio-based 12-aminododecanoic acid, polyetheramine, reaction aid and water are mixed, heated and stirred uniformly in a preparation tank to form a mixture;

[0089] (2) Feeding: Pressurizing the mixture into the polymerization reactor by nitrogen pressurization;

[0090] (3) Aggregation: The following operations are performed in sequence through the control system:

[0091] i. Temperature and pressure increase: The mixture in the polymerization reactor is heated and pressurized in stages, gradually raising the temperature to 185°C and the pressure from 0.5 MPa to 1.3 MPa in stages;

[0092] ii. Constant temperature and pressure: Keep the temperature no higher than 185℃, the pressure stable, and gradually drain the moisture. The temperature of the material will automatically rise after drainage. The material temperature should not exceed 200℃. When the material temperature rises to a certain temperature, the pressure will be reduced in stages, but the pressure must always be maintained at no less than 0.8MPa;

[0093] iii. Temperature increase and pressure reduction: the material temperature is gradually increased, the pressure is reduced to normal pressure, and the material temperature is controlled at 240°C;

[0094] iv. Constant temperature and pressure: Keep the temperature constant and purge with nitrogen for 1 hour. The initial nitrogen flow rate is higher than the final flow rate.

[0095] v. Constant temperature vacuum: keep the temperature constant and evacuate to 0.06 MPa;

[0096] vi. Nitrogen pressurization: The polymer melt is discharged by nitrogen pressurization and then pelletized underwater to obtain bio-based nylon 12 elastomer 3#;

[0097] The reaction aids include interchain compatibility agents, segment regulators, catalysts and antioxidants, and the addition amounts are 4%, 8%, 0.05% and 0.3% of the total raw material mass, respectively.

[0098] The mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine, and water is 1:0.35:0.45. The interchain compatibility agent is p-hydroxyphenylacetic acid; the segment modifiers are sebacic acid and adipic acid in a mass ratio of 2:1. The catalyst includes a first catalyst and a second catalyst, with the mass ratio of the first catalyst to the second catalyst being 5:1. The first catalyst is phosphotungstic acid, and the second catalyst is phosphoric acid. The antioxidant is Antioxidant 1098.

[0099] In step (1), the temperature is 100°C and the time is 10 min; in step (2), the nitrogen boost pressure is 0.5 MPa;

[0100] In step (3), the temperature and pressure raising stage adopts three-stage temperature and pressure raising: the initial temperature is 120°C, the pressure is 0.5 MPa, and the time is 25 min; the middle temperature is 160°C, the pressure is 0.8 MPa, and the time is 40 min; the late temperature is 185°C, the pressure is 1.3 MPa, and the time is 30 min.

[0101] In the constant temperature and pressure holding stage of step (3), the polymerization dehydration time is 3.5 hours, the trigger temperature for the staged pressure reduction is 195°C, the pressure reduction rate is 0.1 MPa / min, and the reaction time in the constant temperature and pressure holding stage is 3 hours; the reaction time in the temperature rising and pressure reducing stage is 1.5 hours; the nitrogen purge in the constant temperature and normal pressure stage includes three gradient stages in sequence: a. 0-20 minutes, flow rate 1.5 L / min; b. 20-40 minutes, flow rate 1.0 L / min; c. 40-60 minutes, flow rate 0.5 L / min; the reaction time in the constant temperature and vacuum stage is 60 minutes; the nitrogen pressurization stage time is 15 minutes, and the pressure is 0.5 MPa.

[0102] Example 4 Bio-based nylon 12 elastomer-4#

[0103] The preparation method of bio-based nylon 12 elastomer-4# comprises the following steps:

[0104] (1) Preparation: Bio-based 12-aminododecanoic acid, polyetheramine, reaction aid and water are mixed, heated and stirred uniformly in a preparation tank to form a mixture;

[0105] (2) Feeding: Pressurizing the mixture into the polymerization reactor by nitrogen pressurization;

[0106] (3) Aggregation: The following operations are performed in sequence through the control system:

[0107] i. Temperature and pressure increase: The mixture in the polymerization reactor is heated and pressurized in stages, gradually raising the temperature to 185°C and the pressure from 0.5 MPa to 1.3 MPa in stages;

[0108] ii. Constant temperature and pressure: Keep the temperature no higher than 185℃, the pressure stable, and gradually drain the moisture. The temperature of the material will automatically rise after drainage. The material temperature should not exceed 200℃. When the material temperature rises to a certain temperature, the pressure will be reduced in stages, but the pressure must always be maintained at no less than 0.8MPa;

[0109] iii. Temperature increase and pressure reduction: the material temperature is gradually increased, the pressure is reduced to normal pressure, and the material temperature is controlled at 230°C;

[0110] iv. Constant temperature and pressure: Keep the temperature constant and purge with nitrogen for 1 hour. The initial nitrogen flow rate is higher than the final flow rate.

[0111] v. Constant temperature vacuum: keep the temperature constant and evacuate to 0.06 MPa;

[0112] vi. Nitrogen pressurization: The polymer melt is discharged by nitrogen pressurization and then pelletized underwater to obtain bio-based nylon 12 elastomer 4#;

[0113] The reaction aids include interchain compatibility agent, segment regulator, catalyst and antioxidant, and the addition amounts are 2%, 4%, 0.04% and 0.2% of the total raw material mass, respectively.

[0114] The mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine, and water is 1:0.2:0.3. The interchain compatibility agent is p-hydroxyphenylacetic acid or; the segment regulators are sebacic acid and adipic acid in a mass ratio of 2:1. The catalyst includes a first catalyst and a second catalyst, with the mass ratio of the first catalyst to the second catalyst being 4:1. The first catalyst is phosphotungstic acid, and the second catalyst is phosphoric acid. The antioxidant is H10.

[0115] In step (1), the temperature is 90°C and the time is 20 min; in step (2), the nitrogen boost pressure is 0.3 MPa;

[0116] In step (3), the temperature and pressure raising stage adopts three-stage temperature and pressure raising: the initial temperature is 120°C, the pressure is 0.5 MPa, and the time is 20 min; the middle temperature is 170°C, the pressure is 0.8 MPa, and the time is 30 min; the late temperature is 185°C, the pressure is 1.3 MPa, and the time is 60 min.

[0117] In the constant temperature and pressure holding stage of step (3), the polymerization dehydration time is 2.5 h, the trigger temperature for the staged pressure reduction is 195°C, the pressure reduction rate is 0.1 MPa / min, and the reaction time in the constant temperature and pressure holding stage is 3.0 h; the reaction time in the temperature rising and pressure reducing stage is 1.2 h; the nitrogen purge in the constant temperature and normal pressure stage includes three gradient stages in sequence: a. 0-20 min, flow rate 1.5 L / min; b. 20-40 min, flow rate 1.0 L / min; c. 40-60 min, flow rate 0.5 L / min; the reaction time in the constant temperature vacuum stage is 40 min; the nitrogen pressurization stage time is 10 min, and the pressure is 0.4 MPa.

[0118] Example 5 Bio-based nylon 12 elastomer-5#

[0119] The preparation method of bio-based nylon 12 elastomer-5# comprises the following steps:

[0120] (1) Preparation: Bio-based 12-aminododecanoic acid, polyetheramine, reaction aid and water are mixed, heated and stirred uniformly in a preparation tank to form a mixture;

[0121] (2) Feeding: Pressurizing the mixture into the polymerization reactor by nitrogen pressurization;

[0122] (3) Aggregation: The following operations are performed in sequence through the control system:

[0123] i. Temperature and pressure increase: The mixture in the polymerization reactor is heated and pressurized in stages, gradually raising the temperature to 180°C and the pressure from 0.5 MPa to 1.3 MPa in stages;

[0124] ii. Constant temperature and pressure: Keep the temperature no higher than 185℃, the pressure stable, and gradually drain the moisture. The temperature of the material will automatically rise after drainage. The material temperature should not exceed 200℃. When the material temperature rises to a certain temperature, the pressure will be reduced in stages, but the pressure must always be maintained at no less than 0.8MPa;

[0125] iii. Temperature increase and pressure reduction: the material temperature is gradually increased, the pressure is reduced to normal pressure, and the material temperature is controlled at 230°C;

[0126] iv. Constant temperature and pressure: Keep the temperature constant and purge with nitrogen for 1 hour. The initial nitrogen flow rate is higher than the final flow rate.

[0127] v. Constant temperature vacuum: keep the temperature constant and evacuate to 0.06 MPa;

[0128] vi. Nitrogen pressurization: The polymer melt is discharged by nitrogen pressurization and then pelletized underwater to obtain bio-based nylon 12 elastomer 5#;

[0129] The reaction aids include an interchain compatibility agent, a segment regulator, a catalyst, and an antioxidant, with the added amounts being 2%, 5%, 0.04%, and 0.2% of the total raw material mass, respectively. The mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine, and water is 1:0.08:0.2. The interchain compatibility agent is p-hydroxyphenylacetic acid; the segment regulators are sebacic acid and adipic acid, with a mass ratio of 2:1. The catalyst includes a first catalyst and a second catalyst, with the mass ratio of the first catalyst to the second catalyst being 4:1. The first catalyst is phosphotungstic acid, and the second catalyst is phosphoric acid. The antioxidant is antioxidant 1010.

[0130] In step (1), the temperature is 90°C, the time is 20 min, and the stirring rate is 100 rpm; in step (2), the nitrogen boost pressure is 0.3 MPa;

[0131] In step (3), the temperature and pressure raising stage adopts three-stage temperature and pressure raising: the initial temperature is 120°C, the pressure is 0.5 MPa, and the time is 20 min; the middle temperature is 160°C, the pressure is 0.8 MPa, and the time is 40 min; the late temperature is 180°C, the pressure is 1.3 MPa, and the time is 50 min.

[0132] In the constant temperature and pressure holding stage of step (3), the polymerization dehydration time is 2.5 h, the trigger temperature for the staged pressure reduction is 195 ° C, the pressure reduction rate is 0.1 MPa / min, and the reaction time of the constant temperature and pressure holding stage is 3 h; the reaction time of the temperature increase and pressure reduction stage is 1.5 h; the nitrogen purge in the constant temperature and normal pressure stage includes three gradient stages in sequence: a. 0-20 min, flow rate 1.5 L / min; b. 20-40 min, flow rate 1.0 L / min; c. 40-60 min, flow rate 0.5 L / min; the reaction time of the constant temperature vacuum stage is 45 min; the nitrogen pressurization stage time is 12 min, and the pressure is 0.4 MPa.

[0133] Example 6 Bio-based nylon 12 elastomer-6#

[0134] The difference between Example 6 and Example 1 is that a single catalyst is used in Example 6, and the catalyst is phosphoric acid.

[0135] Comparative Example 1: Bio-based nylon 12 elastomer-1#

[0136] The difference between Comparative Example 1 and Example 1 is that no interchain compatibilizer is added to the raw materials in Comparative Example 1.

[0137] Comparative Example 2: Bio-based nylon 12 elastomer-2#

[0138] The difference between Comparative Example 2 and Example 1 is that the amount of the segment regulator added to the raw materials in Comparative Example 2 is 1% by weight of the total raw materials.

[0139] Comparative Example 3: Bio-based nylon 12 elastomer-3#

[0140] The difference between Comparative Example 3 and Example 1 is that in the constant temperature and pressure holding stage of step (3) in Comparative Example 3, the pressure is reduced in stages when the material temperature reaches 230°C.

[0141] Comparative Example 4: Bio-based nylon 12 elastomer-4#

[0142] The difference between Comparative Example 4 and Example 1 is that in the constant temperature and pressure holding stage of step (3) in Comparative Example 4, the pressure is finally reduced to 0.4 MPa.

[0143] Comparative Example 5: Bio-based nylon 12 elastomer-5#

[0144] The difference between Comparative Example 5 and Example 1 is that in the temperature and pressure increasing stage of step (3) in Comparative Example 5, the temperature is kept constant at 180° C., the pressure is 1.3 MPa, and the time is 1.2 h.

[0145] Experimental example

[0146] 1. The molecular weight and distribution of bio-based nylon 12 elastomers 1#-6# prepared in Examples 1-6 were tested;

[0147] 2. The bio-based nylon 12 elastomers 1#-6# prepared in Examples 1-6 and the comparative bio-based nylon 12 elastomers 1#-# prepared in Comparative Examples 1-5 were tested for mechanical and optical properties. Table 1 lists the test items and methods, and Tables 2 and 3 provide the experimental data.

[0148] Table 1 Experimental test items and methods

[0149]

[0150] Table 2 Molecular weight and distribution of Examples 1-6

[0151]

[0152] Table 3 Experimental data

[0153]

[0154] The above performance test results demonstrate that the bio-based nylon 12 elastomer prepared using the raw material system and one-step process defined in this application exhibits uniform molecular weight distribution and excellent comprehensive mechanical properties. The samples in Examples 1-4 all exhibited elongation at break ≥500% and compression set ≤27%, while also demonstrating excellent tensile strength and impact toughness.

[0155] Its high elongation at break (≥500%) and low compression set (≤27%) enable it to provide adequate cushioning and protection when used as shoe soles and sports protective gear, meeting the demands of high-intensity exercise. Its excellent overall mechanical properties also enable it to provide both good cushioning and a degree of support and protection in soft structural components, automotive sealing strips, or medical cushioning materials. This demonstrates that the present invention effectively enhances the material's flexibility and energy absorption capacity, meeting the demands of high-performance thermoplastic elastomer applications.

[0156] In Example 5, the amount of polyetheramine used was below the specified range in this application, resulting in insufficient soft segments, decreased elongation at break, and increased compression set. In Example 6, a single catalyst was used, leading to insufficient polycondensation efficiency, a broad molecular weight distribution, decreased elongation at break, and a large compression set.

[0157] In Comparative Example 1, no interchain compatibility agent was added, and the mechanical properties were relatively poor. The reason for this was the lack of effective hydrogen bond network support inside the material, unstable polymerization interface, and loose interchain connections. In Comparative Example 2, the amount of segment regulator added was low, and the results showed that its structural regularity was too strong, the elongation and impact toughness decreased significantly, and the compression permanent deformation increased. In Comparative Example 3, the pressure reduction trigger temperature in the constant temperature and pressure holding stage was too high, and the polymer was prone to chain degradation or main chain cleavage reaction at high temperature, resulting in a decrease in the mechanical properties of the material. In Comparative Example 4, the pressure in the constant temperature and pressure holding stage was too low, the polymerization dehydration efficiency was insufficient, and the polymerization chain segments were unevenly terminated, resulting in deterioration of the mechanical properties. In Comparative Example 5, no staged temperature and pressure increase was adopted, but a single stage continuous reaction was used, which easily led to a too fast system heating rate, out-of-control local polymerization rate, wide molecular weight distribution, and uneven segment length, which ultimately led to a significant decrease in the material's elongation at break and impact properties.

[0158] In summary, the preparation method of bio-based nylon 12 elastomer provided in this application has good effects in terms of polymer chain segment control, reaction stability and polymerization uniformity, and the prepared material has excellent comprehensive mechanical properties.

[0159] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0160] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A one-step method for preparing a bio-based nylon 12 elastomer, characterized in that: The following steps are involved: (1) Preparation: Bio-based 12-aminododecanoic acid, polyetheramine, reaction aid and water are mixed, heated and stirred uniformly in a preparation tank to form a mixture; (2) Feeding: Pressurizing the mixture into the polymerization reactor by nitrogen pressurization; (3) Aggregation: The following operations are performed in sequence through the control system: i. Temperature and pressure increase: The mixture in the polymerization reactor is heated and pressurized in stages, gradually raising the temperature to 170-185°C and the pressure from 0.5 MPa to 1.3 MPa in stages; ii. Constant temperature and pressure: Keep the temperature no higher than 185℃, the pressure stable, and gradually drain the moisture. The temperature of the material will automatically rise after the water is drained. The material temperature will not exceed 200℃. When the material temperature rises to a certain temperature, the pressure will be reduced in stages. The trigger temperature for staged pressure reduction is 195℃, but the pressure must always be maintained at no less than 0.8MPa. iii. Temperature increase and pressure reduction: the material temperature is gradually increased, the pressure is reduced to normal pressure, and the material temperature is controlled at 220-240℃; iv. Constant temperature and pressure: Keep the temperature constant and purge with nitrogen for 0.5-1h. The initial nitrogen flow rate should be higher than the final flow rate. v. Constant temperature vacuum: keep the temperature constant and evacuate to 0.06-0.09 MPa; vi. Nitrogen pressurization: The polymer melt is discharged by nitrogen pressurization and pelletized underwater to obtain a bio-based nylon 12 elastomer; The reaction aids include an interchain compatibility agent, a segment regulator, a catalyst, and an antioxidant, with the added amounts being 1-4%, 3-8%, 0.03-0.05%, and 0.1-0.3% of the total raw material mass, respectively; the interchain compatibility agent is p-hydroxyphenylacetic acid or 3-hydroxypropionic acid; and the segment regulator is sebacic acid and / or adipic acid.

2. The preparation method according to claim 1, characterized in that The mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine and water is 1:(0.15-0.35):(0.2-0.5).

3. The preparation method according to claim 1, characterized in that In the constant temperature and pressure holding stage of step (3), the polymerization dehydration time is 2-3.5 h, and the pressure reduction rate is 0.05-0.1 MPa / min.

4. The preparation method according to claim 1, characterized in that Step (3) The temperature and pressure increase stage adopts three-stage temperature and pressure increase: The initial temperature is 110-120°C, the pressure is 0.5-0.6 MPa, and the time is 20-25 minutes; The middle stage temperature is 160-170℃, the pressure is 0.7-0.9 MPa, and the time is 30-40 minutes; The later temperature is 180-185℃, the pressure is 1.1-1.3 MPa, and the time is 30-60min.

5. The preparation method according to claim 1, characterized in that The segment regulators are sebacic acid and adipic acid in a mass ratio of (2-2.2):

1.

6. The preparation method according to claim 1, characterized in that The catalyst includes a first catalyst and a second catalyst, and the mass ratio of the first catalyst to the second catalyst is (3-5):

1.

7. The preparation method according to claim 6, characterized in that The first catalyst is phosphotungstic acid, and the second catalyst is phosphoric acid or sodium phosphite; The antioxidant is one or more of antioxidant 1010, antioxidant H10 and antioxidant 1098.

8. The preparation method according to claim 1, characterized in that In step (1), the temperature is 80-100°C and the time is 10-30 min; in step (2), the nitrogen boost pressure is 0.2-0.5 MPa; In step (3), the reaction time of the constant temperature and pressure holding stage is 2.5-3.5h; the reaction time of the temperature rising and pressure reducing stage is 1-1.5h; the nitrogen purge flow rate of the constant temperature and normal pressure stage is 0.5-1.5L / min; the reaction time of the constant temperature and vacuum stage is 30-60min; the nitrogen pressurization stage time is 10-15min, and the pressure is 0.3-0.5 MPa.

9. A bio-based nylon 12 elastomer prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The bio-based nylon 12 elastomer has an elongation at break of not less than 500% and a compression permanent deformation of less than 30%.

10. The use of the bio-based nylon 12 elastomer according to claim 9, characterized in that: The bio-based nylon 12 elastomer can be used for shoe soles, soft structural parts, sports protective gear, automobile sealing strips or medical cushioning materials.

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