Bio-based nylon 12 elastomer prepared by one-step method as well as preparation method and application of bio-based nylon 12 elastomer

Abstract

The invention discloses a bio-based nylon 12 elastomer prepared by a one-step method and a preparation method and application thereof, and belongs to the technical field of polyamide materials, the method comprises the following steps: (1) material preparation: mixing, heating and uniformly stirring bio-based 12-amino dodecanoic acid, polyether amine, a reaction aid and water in a material preparation tank to form a mixture; (2) feeding: pressing the mixture into a polymerization kettle through nitrogen pressurization; and (3) polymerizing. By optimizing the raw material combination and the polymerization process path, the one-step method (namely, in the same polymerization kettle) is realized to complete the polymerization reaction taking the bio-based 12-amino dodecanoic acid monomer as the main component, and the polyether block amide type nylon 12 elastomer is constructed, so that the elongation at break and the rebound resilience are improved, the stable polymerization process and the controllable product quality are realized, and the production cost is reduced. And the polyurethane elastomer has good elasticity and machinability, and is suitable for the fields of soles, sealing strips, soft devices and the like.

Description

Technical Field

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

[0002] Nylon elastomers are a class of polymer materials that simultaneously have rigid amide segments and flexible segments, and have good tensile properties, flexibility and wear resistance. This type of material combines the mechanical strength and thermal stability of nylon, as well as the elasticity and resilience of rubber-like materials, and has developed rapidly in recent years in the directions of hard-soft integrated composites and green alternative rubbers. Among them, nylon elastomers represented by polyether block amide (PEBA) have excellent low-temperature toughness, good chemical stability and processing adaptability.

[0003] However, existing PEBA materials are mostly prepared from petroleum-based monomers (such as petroleum-based 12-aminododecanoic acid), which are difficult to meet the trend of green, low-carbon and sustainable development. At the same time, traditional processes generally use melt blending extrusion or multi-step polymerization routes. The multi-step polymerization reaction has a long process, high energy consumption, complex process control, and the molecular structure of the final product is likely to be irregular, resulting in fluctuations in mechanical properties. Chinese Patent CN 115785657B discloses a nylon 12 elastomer material, its preparation method and application, which adopts a scheme of mixing and melt extrusion with a toughening agent, a hyperbranched resin and an alkylbenzenesulfonic acid, and a nylon 12 elastomer with better impact resistance and burst resistance is prepared. However, its scheme still takes physical blending as the core, does not achieve one-step polymerization at the monomer level, lacks a block copolymerization bonding relationship in structure, and there is still a phase boundary between the flexible segment and the rigid segment, resulting in limited overall performance of the polymer.

[0004] In addition, during the polymerization process of nylon elastomers, there are also two significant problems: 1. The problem of uncoordinated structural matching and intermolecular forces: Due to the large polarity difference between the polyamide segment and the polyether segment, the compatibility between the segments is often poor, the interfacial stress is large, and it is difficult to balance the tensile properties and elongation at break of the whole material. If the structure is not properly regulated, problems such as uneven segment distribution, instability of the crystalline and non-crystalline regions are likely to occur, affecting the flexibility, resilience and molding stability of the material.

[0005] 2. Reaction runaway problem during the polymerization process: Polyamide monomers such as 12-aminododecanoic acid will quickly enter the polycondensation reaction stage when heated to near the melting point. If the temperature is not properly controlled or the system pressure changes violently, "explosive polymerization" or "depolymerization" is extremely likely to occur, resulting in coking and yellowing of the product, breakage of molecular chains, and even coking in the reactor. In addition, due to the characteristics of flexible chain segments such as polyetheramine, which are highly viscous and easily oxidized, if by-products and small molecules are not discharged smoothly during the reaction, it will further affect the melt fluidity and molding uniformity, resulting in unstable material properties. Summary of the Invention

[0006] To solve the above problems, a method for preparing a bio-based nylon 12 elastomer by a one-step method, its preparation method and application are provided. By optimizing the raw material combination and polymerization process path, a fully block structure of flexible chain segments and rigid chain segments is formed, and a polyether block amide type nylon 12 elastomer is constructed by completing the polymerization reaction mainly based on bio-based 12-aminododecanoic acid monomers in one step (i.e., in the same polymerization kettle). This not only improves the elongation at break and resilience performance, but also realizes the stability of the polymerization process and controllable product quality, with good elasticity and processability, and is applicable to fields such as shoe soles, sealing strips, and soft devices.

[0007] According to one aspect of the present application, a method for preparing a bio-based nylon 12 elastomer by a one-step method is provided, including the following steps: (1) Material preparation: Mix bio-based 12-aminododecanoic acid, polyetheramine, reaction aids, and water in a preparation tank, heat and stir evenly to form a mixture; (2) Feeding: Press the mixture into the polymerization kettle through nitrogen pressurization; (3) Polymerization: Sequentially perform the following operations through the control system: i. Heating and pressurizing: Gradually heat and pressurize the mixture in the polymerization kettle in stages, gradually raise the temperature to 170-185 °C, and the pressure is increased in stages from 0.5 MPa to 1.3 MPa; ii. Constant temperature and constant pressure: Keep the temperature not higher than 185 °C, the pressure remains stable, gradually drain the water, and the material temperature will rise automatically after the water is drained. The material temperature is not higher than 200 °C. When the material temperature rises to a certain temperature, start to reduce the pressure in stages, but the pressure needs to be maintained not less than 0.8 MPa at all times; iii. Heating and pressure reduction: Gradually heat the material, reduce the pressure to atmospheric pressure, and control the material temperature at 220-240 °C; iv. Constant temperature and atmospheric pressure: Keep the temperature unchanged, purge with nitrogen for 0.5-1 h, and the initial nitrogen flow rate is higher than the final flow rate; v. Constant temperature and vacuum: Keep the temperature unchanged, evacuate to 0.06-0.09 MPa; vi. Nitrogen boosting: The polymerized melt is discharged by nitrogen boosting and granulated by underwater hot cutting to obtain the bio-based nylon 12 elastomer.

[0008] Among them, the reaction aids include an interchain compatibilizer, a chain segment regulator, a catalyst, and an antioxidant, 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.

[0009] Specifically, the polymerization kettle of the present application is equipped with a special feeding tank, and the raw material suspension that has been mixed well and has an appropriate temperature can be immediately pressed into the polymerization kettle in a waiting state by nitrogen pressure, so as to realize seamless intermittent polymerization continuous production. The control system used in step (3) is a DCS control system.

[0010] Optionally, the mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine, and water is 1:(0.15-0.35):(0.2-0.5).

[0011] 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 stepwise pressure reduction is 195 °C, and the pressure reduction rate is 0.05-0.1 MPa / min.

[0012] Furthermore, the present application uses 12-aminododecanoic acid as the core monomer for polymerization reaction. During the research and development of the one-step method for preparing bio-based nylon 12 using 12-aminododecanoic acid as the monomer, the inventors of the present application found that there are two core problems in the polymerization process of 12-aminododecanoic acid: The first problem is that when the temperature rises to near the melting point, a polymerization reaction will occur rapidly. At this time, if the pressure and temperature are not properly controlled, it will cause either explosive polymerization or depolymerization, affecting the transparency of the product.

[0013] Therefore, in the second stage of polymerization, that is, the constant temperature and pressure holding stage, the present application first precisely controls the polymerization dehydration temperature not to exceed 185 °C, maintains the pressure stability and controls the drainage time, so that it is in a solid-liquid coexistence state in this stage, the lattice gap expands, enabling efficient diffusion of water molecules, and at the same time controls the pressure to maintain the existence of liquid water to avoid premature vaporization resulting in volume expansion and destruction of the material structure. Meanwhile, due to the enthalpy change of the polycondensation reaction, heat is released during the process of removing water, and the material temperature will rise automatically, starting the melt polymerization. In order to further remove water and other impurities to increase the viscosity, and at the same time avoid yellowing, the present application starts to gradually reduce the pressure when the temperature reaches the trigger temperature, and maintains the minimum pressure above 0.8 MPa. At this time, the melt stability is maintained by high pressure, and at the same time the reverse polycondensation reaction is inhibited, enabling the material to polymerize stably and fully discharge water molecules.

[0014] The second problem, which is also the most significant feature differentiating it from other nylons, is that due to the too-fast polymerization rate, many small molecules do not have enough time to be discharged outside the polymer system. As the viscosity increases in the later stage of polymerization, the discharge becomes slower and slower, ultimately resulting in uneven viscosity, too wide molecular weight distribution, poor mechanical properties, and even inability to perform normal strand cutting and pelletizing.

[0015] In response to this, in the fourth stage (constant temperature and atmospheric pressure stage) of polymerization in this application, an appropriate amount of nitrogen is blown in, and the initial flow rate of nitrogen is controlled to be higher than the final flow rate. The initial high flow rate causes the nitrogen to form a turbulent flow on the melt surface, forming a vortex to peel off the boundary layer, accelerating the removal of free small molecules (water, oligomers, other organic substances, etc.). The intermediate transitional flow continuously removes the residual substances at the grain boundaries, and the laminar flow in the later stage maintains the stable state of the material.

[0016] Optionally, in the temperature and pressure increasing stage of step (3), three-stage temperature and pressure increase are adopted: The initial temperature is 110 - 120 °C, the pressure is 0.5 - 0.6 MPa, and the time is 20 - 25 min; The intermediate temperature is 160 - 170 °C, the pressure is 0.7 - 0.9 MPa, and the time is 30 - 40 min; The later temperature is 180 - 185 °C, the pressure is 1.1 - 1.3 MPa, and the time is 30 - 60 min.

[0017] Furthermore, to improve the compatibility between the polyamide segment and the polyether segment and achieve the polymerization rate matching between the flexible chain segment and the rigid main chain, this application adopts a three-stage temperature and pressure increase control strategy in the temperature and pressure increasing stage. Through the step-by-step temperature and pressure increase method of "low-temperature pre-distribution + medium-temperature synergistic reaction + high-temperature polymerization activation", the monomers with obvious structural differences in the system are orderly activated and participate in the reaction at different stages, constructing a block connection reaction path. The specific settings are as follows: In the initial stage, the molecular structure of polyetheramine is flexible, with a low boiling point and high activity, and 12-aminododecanoic acid has not yet reacted in large quantities. By setting a lower temperature and medium pressure, it is beneficial for polyetheramine to be fully dispersed in the system, undergo a slight pre-reaction, or form a weak hydrogen bond complex with the chain compatibilizer, forming a preliminary molecular uniform distribution state, laying a foundation for the subsequent block reaction. This stage can also effectively inhibit the high-temperature oxidation, volatilization, or migration of polyetheramine.

[0018] In the intermediate stage, it is in the peak interval of the activation reaction rate of the amino group of polyetheramine, and at the same time, 12-aminododecanoic acid starts to undergo polycondensation reaction. At this time, setting medium-high temperature and continuously increasing the pressure makes the activities of the two main monomers relatively close, which can promote the simultaneous participation of the flexible chain segment and the hard segment in polymerization, construct a block copolymer structure or an alternating structure, and effectively control the block length distribution and improve the regularity of the main chain.

[0019] In the later stage, it is the high-activity region of the polymerization reaction. The polycondensation 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 constant pressure dehydration", and at the same time preventing the premature boiling of water vapor from causing melt explosion polymerization, coking or chain segment damage.

[0020] Optionally, the inter-chain compatibilizer is p-hydroxyphenylacetic acid or 3-hydroxypropionic acid; the chain segment regulator is sebacic acid and / or adipic acid. The chain segment regulator is sebacic acid and adipic acid, and the mass ratio is (2 - 2.2):1 Preferably, the chain segment regulator is sebacic acid and adipic acid, and the mass ratio is 2:1.

[0021] Specifically, by adding the inter-chain compatibilizer, it can form stable hydrogen bond complexes or intermolecular bridging structures with the amino groups and hydroxyl groups in polyetheramine, or with the amino groups / carboxyl groups of bio-based 12-aminododecanoic acid. In the early stage of polymerization, they act as "molecular bridges" to enhance the spatial compatibility between the rigid segments (nylon structure) and flexible segments (polyether segments) of the main chain. Some carboxyl groups can also participate in the amide polycondensation reaction and act as "embedded structure regulating monomers" to construct the regularity of chain segment distribution, effectively improving the compatibility between chain segments. By adding the chain segment regulator, it can act as a molecular weight regulator and a capping agent in the reaction, which can not only adjust the polymerization rate but also control the length of the main chain sequence; in the later stage of polymerization, it acts as a chain terminator to inhibit the infinite growth of the main chain and form block segments of uniform length. Among them, sebacic acid preferentially improves flexibility and chain segment regularity, and adipic acid can enhance the micro-regular structure of the crystalline region. The combination of the two has a good synergistic effect on regulating the molecular weight distribution and the uniformity of block length.

[0022] 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.

[0023] Optionally, 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.

[0024] Specifically, by using phosphotungstic acid as the first catalyst and combining it with the second catalyst, while ensuring the efficiency of the amide polycondensation reaction, it effectively regulates the acid stability and reaction selectivity of the system, taking into account high catalytic activity and low side reaction risk. It is suitable for the elastomer polymerization system sensitive to the flexible chain segment structure. While ensuring the integrity of the polymer chain, it effectively avoids the degradation of the polyether segment and the yellowing of the product, and improves the structural stability and mechanical properties of the final product.

[0025] Optionally, in step (1), the temperature is 80 - 100 °C and the time is 10 - 30 min; in step (2), the nitrogen boosting pressure is 0.2 - 0.5 MPa; In step (3), the reaction time in the constant temperature and pressure maintaining stage is 2.5 - 3.5 h; the reaction time in the heating and pressure reducing stage is 1 - 1.5 h; the nitrogen purging flow rate in the constant temperature and normal pressure stage is 0.5 - 1.5 L / min; the reaction time in the constant temperature and vacuum stage is 30 - 60 min; the time in the nitrogen boosting stage is 10 - 15 min and the pressure is 0.3 - 0.5 MPa.

[0026] Specifically, in the constant temperature and normal pressure stage of step (3), the nitrogen purging includes three gradient stages in sequence: a. 0 - 20 min, the flow rate is 1.5 L / min; b. 20 - 40 min, the flow rate is 1.0 L / min; c. 40 - 60 min, the flow rate is 0.5 L / min.

[0027] According to another aspect of the present application, there is also provided a bio - based nylon 12 elastomer prepared by the above - mentioned preparation method, and the elongation at break of the bio - based nylon 12 elastomer is not less than 500%, and the compression set is less than 30%.

[0028] According to still another aspect of the present application, there is also provided the application of the bio - based nylon 12 prepared by the above - mentioned preparation method, and the bio - based nylon 12 elastomer can be used for shoe soles, soft structural parts, sports protectors, automotive sealing strips or medical cushioning materials.

[0029] The beneficial effects of the present application include but are not limited to: 1. For the method of preparing the bio - based nylon 12 elastomer by the one - step method according to the present application, the present application uses bio - based 12 - aminododecanoic acid as the main monomer to polymerize with polyetheramine to prepare nylon 12 elastomer by one - step method. By introducing a flexible chain segment structure to construct a polyether block amide backbone, and at the same time using reaction aids such as chain - compatible agents to adjust hydrogen bonding, the compatibility of rigid and flexible chain segments is improved, the chain segment synergistic effect is enhanced, and the elongation at break, flexibility and elastic recovery ability of the elastomer are significantly improved. The elongation at break of the prepared product can reach more than 500%, and the compression set is less than 30%, with excellent mechanical properties.

[0030] 2. For the method of preparing the bio - based nylon 12 elastomer by the one - step method according to the present application, by adopting staged heating and boosting pressure, various monomers are gradually activated to participate in polymerization, effectively avoiding the risks of insufficient participation of the polyether segment, irregular chain segments or residues; at the same time, the combined method of multi - stage nitrogen purging and constant temperature and vacuum is adopted to effectively remove moisture, oligomers and free amine molecules, ensuring uniform molecular weight distribution and stable performance of the polymer.

[0031] 3. The method for preparing the bio-based nylon 12 elastomer by the one-step method according to the present application uses phosphotungstic acid as the first catalyst and combines with phosphoric acid or sodium phosphite to form a synergistic catalytic system, which has high reaction efficiency, good thermal stability and yellowing inhibition ability; it also uses a specific molecular weight regulator, which can assist in the formation of amide bonds during the reaction and achieve end-capping in the later stage, effectively controlling the upper limit of the molecular weight, restricting abnormal chain growth, while reducing the probability of side reactions and improving the consistency and molding processability of the finished product.

[0032] 4. The method for preparing the bio-based nylon 12 elastomer by the one-step method according to the present application integrates the entire polymerization process into a single polymerization kettle through the use of a feeding tank to match the six-stage full-process control of a single kettle, achieving high-efficiency continuous production by the one-step method. Compared with the traditional stepwise polymerization or blending process, it has the advantages of short process, low energy consumption and strong batch stability, and is suitable for rapid promotion in pilot scale and industrialization. Detailed implementation mode

[0033] The following describes the present application in detail with reference to the examples, but the present application is not limited to these examples.

[0034] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. The reagents or raw materials used in the present invention can be obtained through conventional channels. Unless otherwise specified, the reagents or raw materials used in the present invention are used in the conventional manner in the art or in accordance with the product instructions. In addition, any methods and materials similar or equivalent to the described content can be applied to the method of the present invention. The preferred implementation methods and materials described in this patent are only for demonstration purposes.

[0035] Among them, the bio-based 12-aminododecanoic acid used in the present application is a commercially available product, sourced from biological resources such as vegetable oils like castor oil; the polyetheramine is a commercially available product, and the models can be D-230, T-403, M-1000. The polymerization kettle used in the present application with a commercially available external jacket + internal coil double heating system is equipped with a reaction feeding tank. Underwater hot cutting granulation can be carried out by conventional means of the existing technology. The water used in the preparation method is high-purity water or demineralized water, and atmospheric pressure refers to standard atmospheric pressure. The dosage of bio-based 12-aminododecanoic acid in the examples of the present application is 5 kg.

[0036] Example 1 Bio-based nylon 12 elastomer - 1# The preparation method of bio-based nylon 12 elastomer - 1# includes the following steps: (1) Preparation of materials: Mix and heat the bio-based 12-aminododecanoic acid, polyetheramine, reaction auxiliary and water in the feeding tank and stir evenly to form a mixture; (2) Feeding: Press the mixture into the polymerization kettle through nitrogen pressurization; (3) Polymerization: The control system sequentially performs the following operations: i. Heating and pressurizing: Gradually heat and pressurize the mixture in the polymerization kettle in stages, raising the temperature to 180 °C step by step, and increasing the pressure from 0.5 MPa to 1.3 MPa in stages; ii. Constant temperature and pressure maintenance: Keep the temperature not higher than 185 °C, maintain the pressure stable, gradually drain the water. After the water is drained from the material, the temperature will rise automatically. The material temperature is not higher than 200 °C. When the material temperature rises to a certain temperature, start to reduce the pressure in stages, but always maintain the pressure not less than 0.8 MPa; iii. Heating and pressure reduction: Gradually heat the material and reduce the pressure to atmospheric pressure. Control the material temperature at 230 °C; iv. Constant temperature and atmospheric pressure: Keep the temperature constant, purge with nitrogen for 1 h, and the initial nitrogen flow rate is higher than the final flow rate; v. Constant temperature and vacuum: Keep the temperature constant and evacuate to 0.06 MPa; vi. Nitrogen pressurization: Discharge the polymerized melt by nitrogen pressurization, and granulate it by underwater hot cutting to obtain bio-based nylon 12 elastomer No. 1; Among them, the reaction aids include an interchain compatibilizer, a chain segment regulator, a catalyst, and an antioxidant, and the addition amounts are 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 compatibilizer is p-hydroxyphenylacetic acid; the chain segment regulator is sebacic acid and adipic acid, and the mass ratio is 2:1. The catalyst includes a first catalyst and a second catalyst, and the mass ratio of the first catalyst to the second catalyst is 4:1. The first catalyst is phosphotungstic acid, the second catalyst is phosphoric acid; the antioxidant is antioxidant 1010.

[0037] 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 pressurization pressure is 0.3 MPa; In the heating and pressurizing stage of step (3), three-stage heating and pressurizing are adopted: the initial temperature is 120 °C, the pressure is 0.5 MPa, and the time is 20 min; the intermediate temperature is 160 °C, the pressure is 0.8 MPa, and the time is 40 min; the final temperature is 180 °C, the pressure is 1.3 MPa, and the time is 50 min.

[0038] In step (3), the isothermal pressure holding stage has a polymerization dehydration time of 2.5 h, a triggering temperature for stepwise pressure reduction of 195 °C, a pressure reduction rate of 0.1 MPa / min, a reaction time of 3 h for the isothermal pressure holding stage; a reaction time of 1.5 h for the heating and pressure reduction stage; the nitrogen purging in the isothermal normal pressure stage successively includes three gradient stages: a. 0 - 20 min, with a flow rate of 1.5 L / min; b. 20 - 40 min, with a flow rate of 1.0 L / min; c. 40 - 60 min, with a flow rate of 0.5 L / min; the reaction time for the isothermal vacuum stage is 45 min; the time for the nitrogen pressurization stage is 12 min, with a pressure of 0.4 MPa.

[0039] Example 2 Bio-based Nylon 12 Elastomer - 2# The preparation method of Bio-based Nylon 12 Elastomer - 2# comprises the following steps: (1) Material preparation: Mix and heat the bio-based 12-aminododecanoic acid, polyetheramine, reaction aids, and water in a preparation tank and stir evenly to form a mixture; (2) Feeding: Press the mixture into the polymerization kettle through nitrogen pressurization; (3) Polymerization: Sequentially perform the following operations through a control system: i. Heating and pressure increasing: Perform stepwise heating and pressure increasing on the mixture in the polymerization kettle, gradually raise the temperature to 185 °C, and increase the pressure from 0.5 MPa to 1.3 MPa in stages; ii. Isothermal pressure holding: Keep the temperature not higher than 185 °C, keep the pressure stable, gradually discharge water, the temperature of the material will rise automatically after water drainage, the temperature of the material is not higher than 200 °C, start stepwise pressure reduction when the material temperature rises to a certain temperature, but always maintain the pressure not less than 0.8 MPa; iii. Heating and pressure reduction: Gradually heat the material and reduce the pressure to normal pressure, control the material temperature at 220 °C; iv. Isothermal normal pressure: Keep the temperature constant, purge with nitrogen for 1 h for balance, with the initial nitrogen flow rate higher than the final flow rate; v. Isothermal vacuum: Keep the temperature constant and evacuate to 0.09 MPa; vi. Nitrogen pressurization: Discharge the polymerized melt through nitrogen pressurization, and obtain Bio-based Nylon 12 Elastomer 2# through underwater hot cutting granulation; Among them, the reaction aids include an inter-chain compatibilizer, a chain segment regulator, a catalyst, and an antioxidant, and the addition amounts are 1%, 3%, 0.03%, and 0.1% of the total raw material mass respectively.

[0040] The mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine and water is 1:0.15:0.25. The inter-chain compatibilizer is 3-hydroxypropionic acid; the chain segment regulator is sebacic acid and adipic acid, and the mass ratio is 2.2:1. The catalyst includes a first catalyst and a second catalyst, and the mass ratio of the first catalyst to the second catalyst is 3:1. The first catalyst is phosphotungstic acid, and the second catalyst is sodium phosphite; the antioxidant is antioxidant H10.

[0041] In step (1), the temperature is 80 °C and the time is 30 min; in step (2), the nitrogen pressurization pressure is 0.2 MPa; In the temperature and pressure increase stage of step (3), three-stage temperature and pressure increase are adopted: the initial temperature is 110 °C, the pressure is 0.5 MPa, and the time is 25 min; the intermediate temperature is 170 °C, the pressure is 0.8 MPa, and the time is 30 min; the final temperature is 185 °C, the pressure is 1.3 MPa, and the time is 50 min.

[0042] In the constant temperature and pressure holding stage of step (3), the polymerization dehydration time is 2 h, the trigger temperature for stepwise 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 h; the reaction time in the temperature increase and pressure reduction stage is 1 h; the nitrogen purging in the constant temperature and atmospheric pressure stage includes three gradient stages in sequence: a. 0 - 20 min, the flow rate is 1.5 L / min; b. 20 - 40 min, the flow rate is 1.0 L / min; c. 40 - 60 min, the flow rate is 0.5 L / min; the reaction time in the constant temperature and vacuum stage is 30 min; the time in the nitrogen pressurization stage is 10 min, and the pressure is 0.3 MPa.

[0043] Example 3 Bio-based Nylon 12 Elastomer - 3# The preparation method of the bio-based nylon 12 elastomer - 3# includes the following steps: (1) Preparation of materials: Mix and heat the bio-based 12-aminododecanoic acid, polyetheramine, reaction assistant and water in a preparation tank and stir evenly to form a mixture; (2) Feeding: Press the mixture into the polymerization kettle through nitrogen pressurization; (3) Polymerization: The following operations are sequentially performed through a control system: i. Temperature and pressure increase: Implement staged temperature and pressure increase on the mixture in the polymerization kettle, gradually raise the temperature to 185 °C, and the pressure is increased in stages from 0.5 MPa to 1.3 MPa; ii. Constant temperature and pressure holding: Keep the temperature not higher than 185 °C, the pressure remains stable, gradually drain the water, the temperature of the material will rise automatically after the water is drained, the temperature of the material is not higher than 200 °C, and when the temperature of the material rises to a certain temperature, start to reduce the pressure in stages, but the pressure must always be maintained not less than 0.8 MPa; iii. Heating and pressure reduction: The material is gradually heated, and the pressure is reduced to atmospheric pressure. The temperature of the material is controlled at 240 °C; iv. Constant temperature and atmospheric pressure: Keep the temperature unchanged, purge with nitrogen for 1 h to balance, and the initial nitrogen flow rate is higher than the final flow rate; v. Constant temperature and vacuum: Keep the temperature unchanged and evacuate to 0.06 MPa; vi. Nitrogen pressurization: The polymerized melt is discharged by nitrogen pressurization and granulated by underwater hot cutting to obtain bio-based nylon 12 elastomer 3#; Among them, the reaction aids include an inter-chain compatibilizer, a chain segment regulator, a catalyst, and an antioxidant, and the addition amounts are 4%, 8%, 0.05%, and 0.3% of the total raw material mass, respectively.

[0044] The mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine, and water is 1:0.35:0.45. The inter-chain compatibilizer is p-hydroxyphenylacetic acid; the chain segment regulator is sebacic acid and adipic acid, and the mass ratio is 2:1. The catalyst includes a first catalyst and a second catalyst, and the mass ratio of the first catalyst to the second catalyst is 5:1. The first catalyst is phosphotungstic acid, the second catalyst is phosphoric acid; the antioxidant is antioxidant 1098.

[0045] In step (1), the temperature is 100 °C and the time is 10 min; in step (2), the nitrogen pressurization pressure is 0.5 MPa; In the temperature and pressure increase stage of step (3), three-stage temperature and pressure increase are adopted: the initial temperature is 120 °C, the pressure is 0.5 MPa, and the time is 25 min; the intermediate temperature is 160 °C, the pressure is 0.8 MPa, and the time is 40 min; the final temperature is 185 °C, the pressure is 1.3 MPa, and the time is 30 min.

[0046] In the constant temperature and pressure holding stage of step (3), the polymerization dehydration time is 3.5 h, the triggering temperature for stepwise 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 h; the reaction time in the heating and pressure reduction stage is 1.5 h; the nitrogen purge in the constant temperature and atmospheric 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 and vacuum stage is 60 min; the time in the nitrogen pressurization stage is 15 min, and the pressure is 0.5 MPa.

[0047] Example 4 Bio-based nylon 12 elastomer - 4# The preparation method of bio-based nylon 12 elastomer - 4# includes the following steps: (1)Material preparation: Mix bio-based 12-aminododecanoic acid, polyetheramine, reaction aids and water in a preparation tank, heat and stir evenly to form a mixture; (2)Feeding: Press the mixture into the polymerization kettle through nitrogen pressurization; (3)Polymerization: Sequentially perform the following operations through the control system: i. Heating and pressurizing: Gradually heat and pressurize the mixture in the polymerization kettle in stages, gradually raise the temperature to 185 °C, and increase the pressure from 0.5 MPa to 1.3 MPa in stages; ii. Constant temperature and pressure holding: Keep the temperature not higher than 185 °C, keep the pressure stable, gradually drain the water, the temperature of the material will rise automatically after draining the water, the temperature of the material is not higher than 200 °C, when the temperature of the material rises to a certain temperature, start to reduce the pressure in stages, but always maintain the pressure not less than 0.8 MPa; iii. Heating and pressure reduction: Gradually heat the material and reduce the pressure to atmospheric pressure, and control the temperature of the material at 230 °C; iv. Constant temperature and atmospheric pressure: Keep the temperature constant, purge with nitrogen for 1 h, and the initial nitrogen flow rate is higher than the final flow rate; v. Constant temperature and vacuum: Keep the temperature constant and evacuate to 0.06 MPa; vi. Nitrogen pressurization: Discharge the polymerized melt through nitrogen pressurization, and granulate it by underwater hot cutting to obtain bio-based nylon 12 elastomer 4#; Among them, the reaction aids include an interchain compatibilizer, a chain segment regulator, a catalyst and an antioxidant, and the addition amounts are 2%, 4%, 0.04% and 0.2% of the total raw material mass respectively.

[0048] The mass ratio of the bio-based 12-aminododecanoic acid, polyetheramine and water is 1:0.2:0.3. The interchain compatibilizer is p-hydroxyphenylacetic acid or; the chain segment regulator is sebacic acid and adipic acid, and the mass ratio is 2:1. The catalyst includes a first catalyst and a second catalyst, and the mass ratio of the first catalyst to the second catalyst is 4:1. The first catalyst is phosphotungstic acid, and the second catalyst is phosphoric acid; the antioxidant is antioxidant H10.

[0049] In step (1), the temperature is 90 °C and the time is 20 min; in step (2), the nitrogen pressurization pressure is 0.3 MPa; In the heating and pressurizing stage of step (3), three-stage heating and pressurizing are adopted: the initial temperature is 120 °C, the pressure is 0.5 MPa, and the time is 20 min; the intermediate temperature is 170 °C, the pressure is 0.8 MPa, and the time is 30 min; the final temperature is 185 °C, the pressure is 1.3 MPa, and the time is 60 min.

[0050] In step (3), the isothermal pressure-holding stage, the polymerization dehydration time is 2.5 h, the trigger temperature for stepwise pressure reduction is 195 °C, the pressure reduction rate is 0.1 MPa / min, the reaction time in the isothermal pressure-holding stage is 3.0 h; the reaction time in the heating and pressure reduction stage is 1.2 h; the nitrogen purging in the isothermal atmospheric pressure stage includes three gradient stages in sequence: a. 0 - 20 min, the flow rate is 1.5 L / min; b. 20 - 40 min, the flow rate is 1.0 L / min; c. 40 - 60 min, the flow rate is 0.5 L / min; the reaction time in the isothermal vacuum stage is 40 min; the time in the nitrogen pressurization stage is 10 min, and the pressure is 0.4 MPa.

[0051] Example 5 Bio-based Nylon 12 Elastomer - 5# The preparation method of Bio-based Nylon 12 Elastomer - 5# comprises the following steps: (1) Material preparation: Mix and heat the bio-based 12-aminododecanoic acid, polyetheramine, reaction auxiliary agent and water in a preparation tank and stir evenly to form a mixture; (2) Feeding: Press the said mixture into a polymerization kettle through nitrogen pressurization; (3) Polymerization: Sequentially perform the following operations through a control system: i. Heating and pressure boosting: Implement stepwise heating and pressure boosting on the mixture in the polymerization kettle, gradually raise the temperature to 180 °C, and the pressure is increased in stages from 0.5 MPa to 1.3 MPa; ii. Isothermal pressure-holding: Keep the temperature not higher than 185 °C, the pressure remains stable, gradually discharge water, the material temperature will rise automatically after water drainage, the material temperature is not higher than 200 °C, when the material temperature rises to a certain temperature, start to reduce the pressure in stages, but the pressure should always be maintained not less than 0.8 MPa; iii. Heating and pressure reduction: Gradually heat the material, reduce the pressure to atmospheric pressure, and control the material temperature at 230 °C; iv. Isothermal atmospheric pressure: Keep the temperature constant, purge with nitrogen for 1 h, and the initial nitrogen flow rate is higher than the final flow rate; v. Isothermal vacuum: Keep the temperature constant, evacuate to 0.06 MPa; vi. Nitrogen pressurization: Discharge the polymerized melt through nitrogen pressurization, and obtain Bio-based Nylon 12 Elastomer 5# through underwater hot cutting granulation; Among them, the reaction aids include an inter-chain compatibilizer, a chain segment regulator, a catalyst, and an antioxidant, and the addition amounts are 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 inter-chain compatibilizer is p-hydroxyphenylacetic acid; the chain segment regulator is sebacic acid and adipic acid, and the mass ratio is 2:1. The catalyst includes a first catalyst and a second catalyst, and the mass ratio of the first catalyst to the second catalyst is 4:1. The first catalyst is phosphotungstic acid, the second catalyst is phosphoric acid; the antioxidant is antioxidant 1010.

[0052] 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 pressurization pressure is 0.3 MPa; In the temperature and pressure increasing stage of step (3), three-stage temperature and pressure increase are adopted: the initial temperature is 120 °C, the pressure is 0.5 MPa, and the time is 20 min; the intermediate temperature is 160 °C, the pressure is 0.8 MPa, and the time is 40 min; the final temperature is 180 °C, the pressure is 1.3 MPa, and the time is 50 min.

[0053] In the constant temperature and pressure maintaining stage of step (3), the polymerization dehydration time is 2.5 h, the trigger temperature for staged pressure reduction is 195 °C, the pressure reduction rate is 0.1 MPa / min, the reaction time in the constant temperature and pressure maintaining stage is 3 h; the reaction time in the temperature and pressure increasing and decreasing stage is 1.5 h; the nitrogen purging in the constant temperature and atmospheric pressure stage includes three gradient stages in sequence: a. 0 - 20 min, the flow rate is 1.5 L / min; b. 20 - 40 min, the flow rate is 1.0 L / min; c. 40 - 60 min, the flow rate is 0.5 L / min; the reaction time in the constant temperature and vacuum stage is 45 min; the time in the nitrogen pressurization stage is 12 min, and the pressure is 0.4 MPa.

[0054] Example 6 Bio-based Nylon 12 Elastomer - 6# The difference between Example 6 and Example 1 is that: in Example 6, a single catalyst is used, and the catalyst is phosphoric acid.

[0055] Comparative Example 1 Comparative Bio-based Nylon 12 Elastomer - 1# The difference between Comparative Example 1 and Example 1 is that: in Comparative Example 1, no inter-chain compatibilizer is added to the raw materials.

[0056] Comparative Example 2 Comparative Bio-based Nylon 12 Elastomer - 2# The difference between Comparative Example 2 and Example 1 is that: in Comparative Example 2, the addition amount of the chain segment regulator in the raw materials is 1% of the total raw material mass.

[0057] Comparative Example 3 Comparative Bio-based Nylon 12 Elastomer - 3# The difference between Comparative Example 3 and Example 1 lies in that: in Comparative Example 3, during the constant temperature and pressure maintaining stage of step (3), when the material temperature reaches 230°C, the pressure is reduced in stages.

[0058] Comparative Example 4: Comparative Bio-based Nylon 12 Elastomer - 4# The difference between Comparative Example 4 and Example 1 lies in that: in Comparative Example 4, during the constant temperature and pressure maintaining stage of step (3), the pressure is finally reduced to 0.4 MPa.

[0059] Comparative Example 5: Comparative Bio-based Nylon 12 Elastomer - 5# The difference between Comparative Example 5 and Example 1 lies in that: in Comparative Example 5, during the temperature and pressure increasing stage of step (3), the constant temperature is 180°C, the pressure is 1.3 MPa, and the time is 1.2 h.

[0060] Experimental Example 1. Test the molecular weight and its distribution of the bio-based nylon 12 elastomers 1# - 6# prepared in Examples 1 - 6; 2. Test the mechanical properties, optical properties, etc. of 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. Table 1 shows the test items and methods, and Tables 2 and 3 show the experimental data.

[0061] Table 1 Experimental Test Items and Methods

[0062] Table 2 Molecular Weight and Its Distribution of Examples 1 - 6

[0063] Table 3 Experimental Data

[0064] From the above performance test results, it can be seen that the bio-based nylon 12 elastomer prepared by using the raw material system and the one-step process defined in this application has a uniform molecular weight distribution and excellent comprehensive mechanical properties. The elongation at break of the samples in Examples 1 - 4 is ≥500%, the compression set is ≤27%, and they perform well in terms of tensile strength and impact toughness.

[0065] High elongation at break (elongation at break ≥ 500%) and low compression set (compression set ≤ 27%) enable it to provide sufficient buffer protection when used as shoe soles and sports protectors, meeting the requirements of high-intensity sports. At the same time, its excellent comprehensive mechanical properties also enable it to be used as a soft structural component, automotive sealing strip or medical buffer material, providing good buffering and certain support protection. The above shows that the solution of the present invention can effectively improve the flexibility and energy absorption capacity of the material, meeting the requirements of high-performance thermoplastic elastomer applications.

[0066] Among them, in Example 5, the dosage of polyetheramine is lower than the proportion range defined in this application, resulting in insufficient flexible chain segments, a decrease in elongation at break, and an increase in compression set. In Example 6, a single catalyst is used, resulting in insufficient polycondensation reaction efficiency and a wide molecular weight distribution, and finally the elongation at break also decreases, and the compression deformation is large.

[0067] In Comparative Example 1, no chain compatibilizer was added, and the mechanical properties were relatively poor. The reason is that there is a lack of effective hydrogen bond network support inside the material, the polymerization interface is unstable, and the inter-chain connection is loose. In Comparative Example 2, the addition amount of the chain segment regulator is too low, and the result shows that the structural regularity recovery is too strong, the elongation at break and impact toughness decrease significantly, and the compression set increases. In Comparative Example 3, the pressure reduction trigger temperature in the constant temperature and pressure holding stage is too high, and the polymer is prone to chain degradation or main chain fracture 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 is too low, the polymerization dehydration efficiency is insufficient, the polymerization chain segments terminate unevenly, resulting in deterioration of the mechanical properties. In Comparative Example 5, instead of using staged temperature and pressure increase, a single-stage continuous reaction is used, which easily leads to too fast a system heating rate, out-of-control local polymerization rate, wide molecular weight distribution, uneven chain segment lengths, and finally significant decreases in the elongation at break and impact performance of the material.

[0068] In summary, the preparation method of the bio-based nylon 12 elastomer provided by this application has good effects in aspects such as polymer chain segment control, reaction stability and polymerization uniformity, and the prepared material has excellent comprehensive mechanical properties.

[0069] Each embodiment in this specification is described in a progressive manner. The same or similar parts between each embodiment can be referred to each other, and the key point of each embodiment is to illustrate the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment.

[0070] The above are only the embodiments of this application and are not used to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the scope of the claims of this application.

Claims

1. A method for preparing a bio-based nylon 12 elastomer by a one-step process, characterized in that, It includes the following steps: (1) Stock preparation: Mix bio-based 12-aminododecanoic acid, polyetheramine, reaction aids and water in a stock preparation tank, heat and stir evenly to form a mixture; (2) Feeding: Press the mixture into the polymerization kettle through nitrogen pressurization; (3) Polymerization: Sequentially perform the following operations through a control system: i. Heating and pressurization: Implement staged heating and pressurization on the mixture in the polymerization kettle, gradually raise the temperature to 170 - 185 °C, and the pressure is raised in stages from 0.5 MPa to 1.3 MPa; ii. Constant temperature and pressure maintenance: Keep the temperature not higher than 185 °C, the pressure remains stable, gradually drain the water, the material temperature will rise automatically after the water is drained, the material temperature is not higher than 200 °C, when the material temperature rises to a certain temperature, start to depressurize in stages, but the pressure needs to be maintained not less than 0.8 MPa all the time; iii. Heating and depressurization: Gradually raise the temperature of the material, lower the pressure to atmospheric pressure, and control the material temperature at 220 - 240 °C; iv. Constant temperature and atmospheric pressure: Keep the temperature unchanged, purge with nitrogen for 0.5 - 1 h, and the initial nitrogen flow rate is higher than the final flow rate; v. Constant temperature and vacuum: Keep the temperature unchanged, evacuate to 0.06 - 0.09 MPa; vi. Nitrogen pressurization: Discharge the polymerized melt through nitrogen pressurization, and obtain bio-based nylon 12 elastomer through underwater hot cutting granulation; Among them, the reaction aids include an inter-chain compatibilizer, a chain segment regulator, a catalyst and an antioxidant, 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; the inter-chain compatibilizer is p-hydroxyphenylacetic acid or 3-hydroxypropionic acid; the chain 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 maintenance stage of step (3), the polymerization dehydration time is 2 - 3.5 h, the trigger temperature for staged depressurization is 195 °C, and the depressurization rate is 0.05 - 0.1 MPa / min.

4. The preparation method according to claim 1, characterized in that, In the heating and pressurization stage of step (3), three-stage heating and pressurization is adopted: The initial temperature is 110 - 120 °C, the pressure is 0.5 - 0.6 MPa, and the time is 20 - 25 min; The middle temperature is 160 - 170 °C, the pressure is 0.7 - 0.9 MPa, and the time is 30 - 40 min; The final temperature is 180 - 185 °C, the pressure is 1.1 - 1.3 MPa, and the time is 30 - 60 min.

5. The preparation method according to claim 1, wherein The chain segment regulator is sebacic acid and adipic acid, and the mass ratio is (2 - 2.2):

1.

6. The preparation method according to claim 1, wherein, 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 pressurization pressure is 0.2 - 0.5 MPa; In step (3), the reaction time in the isothermal and isobaric stage is 2.5 - 3.5 h; the reaction time in the heating and pressure reduction stage is 1 - 1.5 h; the nitrogen purge flow rate in the isothermal and atmospheric pressure stage is 0.5 - 1.5 L / min; the reaction time in the isothermal and vacuum stage is 30 - 60 min; the time in the nitrogen pressurization stage is 10 - 15 min, 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 1-8, characterized in that, The elongation at break of the bio-based nylon 12 elastomer is not less than 500%, and the compression set is less than 30%.

10. The application of the bio-based nylon 12 elastomer according to claim 9, wherein The bio-based nylon 12 elastomer can be used for shoe soles, flexible structural parts, sports protectors, automotive sealing strips or medical cushioning materials.

Images