A multiphase synergistic high-strength high-elasticity polyester elastomer, a preparation method and application thereof

Abstract

The application relates to a multi-phase synergic high-strength high-elasticity polyester elastomer and a preparation method and application thereof, and belongs to the technical field of high polymer material synthesis. The application comprises the following steps: weighing binary acid I, binary alcohol and a hydroxyl-terminated polyether, and performing esterification reaction on terminal carboxyl groups and terminal hydroxyl groups to form an esterification product; polyester oligomers are prepared by performing ester exchange reaction between the terminal hydroxyl groups of the esterification product; caprolactam is added to generate aminocaproic acid by ring-opening reaction, and meanwhile, the aminocaproic acid and part of the polyester oligomers perform esterification reaction to form a multi-component oligomer with terminal amino groups and terminal hydroxyl groups; binary acid II and a solvent are added, and salt formation reaction is performed on the terminal carboxyl groups and the terminal amino groups at low temperature; at high temperature, three forms of polycondensation reactions, i.e., amide bond formation by dehydration of the ammonium salt, ester bond formation by dehydration of the terminal carboxyl groups and the terminal hydroxyl groups, and ester bond formation by dehydration of the binary alcohol between the terminal hydroxyl groups, are synchronously performed to prepare a multi-block polyester elastomer. The hydrogen bond interaction is strengthened, and the tensile strength, tensile modulus and elastic recovery capacity of the elastomer are improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer material synthesis technology, and relates to a multiphase synergistic high-strength and high-elasticity polyester elastomer, its preparation method and application. Background Technology

[0002] Polyester elastomers are a class of polymeric materials whose molecular chains contain both rigid and flexible segments (hard segments), combining the strength of plastics with the elasticity of rubber. They possess a unique microscopic phase-separated structure: the hard segments, composed of aromatic diacids and short-chain diols, act as physical cross-linking points, providing strength and heat resistance; while the soft segments, composed of long-chain aliphatic diacids or polyether diols, impart excellent elasticity and flexibility. This balanced structure allows them to exhibit excellent overall performance at room temperature, while when heated above the melting point of the hard segments, they can be melt-processed like thermoplastics.

[0003] Based on whether a permanent cross-linked network is formed, polyester elastomers are mainly divided into two types: thermoplastic polyester elastomers and cross-linkable polyester elastomers. The former, with its reversible physical cross-linking characteristics, is easy to process and mold through injection molding, extrusion, and other methods, and has the advantage of being recyclable, making it widely used in automotive parts, drive belts, and high-performance wire sheaths. The latter, by introducing unsaturated monomers (such as itaconic acid) to provide chemical cross-linking sites, forms a stable three-dimensional network after vulcanization, thereby obtaining superior creep resistance, solvent resistance, and high-temperature resistance, making it particularly suitable for harsh environments such as tire airtight layers and high-performance seals.

[0004] The most widely used type in commercial applications is thermoplastic polyester elastomer (TPEE), with typical products such as DuPont Hytrel. ® Our series of TPEE, including the domestic Nantai brand, are widely used in the automotive industry, medical and health, electronics and electrical appliances, and flexible packaging. Polyester elastomers, through their tunable molecular structure, achieve a wide range of adjustable properties, making them an indispensable key material in many high-end engineering fields. Furthermore, with the successful application of bio-based monomers, they also demonstrate enormous potential and broad prospects for sustainable development. Thermoplastic polyester elastomers are typically synthesized using melt polycondensation, where the polyester backbone, as the hard segment, needs to possess excellent crystallinity and mechanical properties to act as physical crosslinking points, thereby endowing the elastomer with excellent elastic recovery under high deformation conditions.

[0005] Among currently industrialized conventional polyesters, polybutylene terephthalate (PBT) is often chosen as the hard segment for block copolymerization with long-chain polyether soft segments due to its good crystallinity and high mechanical strength, in order to prepare thermoplastic polyester elastomers with excellent comprehensive properties. However, polyethylene terephthalate (PET) and polypropylene terephthalate (PTT) have weaker crystallinity than PBT, making them difficult to use for preparing high-strength, high-modulus, and high-elasticity polyester elastomers. In the prior art, the patent with publication number CN106967214B ​​first forms diacid-terminated polyamide segments, then terminates them with a monohydric alcohol, and then undergoes an ester exchange reaction with a second monomer and a dihydric alcohol to form a dihydric alcohol-terminated polyesteramide oligomer, which is then subjected to an ester exchange reaction with a dihydric alcohol polyether to prepare a polyesteramide elastomer. However, this patent fails to consider the reactivity of the terminal amino groups in the polyamide oligomer formed by the diacid end-capping agent and the first monomer. Polyamide is easily acidified under high temperature and strong acid conditions, and directly reacting the polyamide oligomer with the diacid end-capping agent at high temperature can easily lead to degradation and color change. In addition, this patent uses three stages to prepare intermediate products separately, and the fourth stage is the final preparation of polyesteramide elastomer. The early stage is dominated by polyamide components, which is not conducive to the continuous production of polyester elastomers with polyester as the main component.

[0006] In summary, although the synthesis technology of thermoplastic polyester elastomers has made great progress, the following problems still exist:

[0007] (1) Currently, in polyester elastomers, as the polyether content increases, the mechanical strength decreases and the elasticity increases. It is difficult to balance mechanical and elastic properties. In the face of market demand for higher performance, it is urgent to improve both mechanical and elastic properties simultaneously.

[0008] (2) Commercial polyester elastomers are mainly PBT-based polyether esters. Due to differences in crystallinity, PET, PTT-based and other polyether esters have weak physical cross-linking of hard segments when used as elastomers, resulting in poor elastic properties and making it difficult to meet the application requirements of elastomers. PET, PTT and other polyesters have unique application properties, so it is necessary to propose a modification method suitable for polyester systems to improve the fixation effect of hard segments in elastomers, improve dimensional stability, enhance elastic properties, and expand the synthesis routes of polyester elastomers. Summary of the Invention

[0009] To address the shortcomings of existing technologies and to resolve the issues of differing crystallinity and weak physical crosslinking in the preparation of polyester elastomers from various polyester-based polyether esters such as PET and PTT, which result in poor mechanical and elastic properties provided by hard segments as physical crosslinking points in polyester elastomers, this invention aims to design and provide a high-elasticity polyester elastomer with a multi-microphase structure based on multi-block copolymerization, using polyester segments as the main chain and introducing polyether and polyamide segments. This simultaneously improves mechanical and elastic properties and broadens the selection of synthetic routes for polyester elastomers. This invention involves a targeted design of the synthetic route and molecular structure, introducing polyamide segments with excellent crystallinity and mechanical properties onto the polyester main chain. This increases crystallinity and strengthens hydrogen bonding interactions, further improving the tensile strength, tensile modulus, and elastic recovery properties of the elastomer, resulting in a high-strength, high-modulus polyester elastomer with excellent elastic recovery. This method is applicable to existing polyester systems such as PET, PTT, and PBT, and can broaden the synthetic routes for polyester elastomers.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] This invention first adds diacid I, diol, and hydroxyl-terminated polyether to reactor I, forming esters through esterification and transesterification reactions. Then, polyester oligomers are prepared by transesterification between the hydroxyl groups of the esterified products, and excess diol is removed. Next, caprolactam is added to reactor I to perform ring-opening to generate aminohexanoic acid. Simultaneously, aminohexanoic acid undergoes esterification with some of the polyester oligomers to form multi-component oligomers with terminal amino and hydroxyl groups. Finally, the multi-component oligomers and diacid II are added to reactor II. First, at low temperature, the terminal carboxyl groups and terminal amino groups undergo a salt-forming reaction. Then, at high temperature, three forms of polycondensation reactions are simultaneously carried out: ammonium salt dehydration to form amide bonds, dehydration of terminal carboxyl groups and terminal hydroxyl groups to form ester bonds, and removal of diols between terminal hydroxyl groups to form ester bonds, to prepare a multi-block polyester elastomer.

[0012] In a first aspect, the present invention provides a method for preparing a multiphase synergistic high-strength and high-elasticity polyester elastomer, comprising the following steps:

[0013] (1) Weigh out dicarboxylic acid I, diol and hydroxyl-terminated polyether and add them to the first reaction vessel. Add catalyst and heat stabilizer to carry out esterification reaction. After vacuuming and heating, carry out transesterification reaction to obtain polyester oligomer containing polyether component and remove excess diol.

[0014] In this step, dicarboxylic acid I, diol, and hydroxyl-terminated polyether are fed together. First, an esterification reaction occurs between the terminal carboxyl group and the terminal hydroxyl group to form an ester. Then, an ester exchange reaction occurs between the terminal hydroxyl group of the ester and the terminal hydroxyl group of the polyether to prepare a polyester oligomer containing the polyether component.

[0015] (2) Weigh caprolactam aqueous solution, heat and melt it and add it to the first reaction vessel. Mix it evenly with the polyester oligomer obtained above. Carry out the hydrolysis and ring-opening reaction of caprolactam under pressure. After slowly depressurizing, carry out the esterification reaction to obtain a multi-component oligomer with terminal amino and terminal hydroxyl groups.

[0016] In this step, caprolactam is added to perform a ring-opening reaction to generate aminohexanoic acid. Aminohexanoic acid has a terminal carboxyl group and a terminal amino group. The terminal carboxyl group of aminohexanoic acid can undergo an esterification reaction with the terminal hydroxyl group of the polyester oligomer generated in the first step to generate water as a byproduct, and attach aminohexanoic acid to the end of the molecular chain of the polyester oligomer.

[0017] It undergoes an esterification reaction with polyester oligomers to form multi-component oligomers with terminal amino and terminal hydroxyl groups.

[0018] (3) Weigh the above-mentioned multi-component oligomer with terminal amino and terminal hydroxyl groups, dicarboxylic acid II and solvent into the second reaction vessel, heat up and stir to dissolve, carry out salt formation reaction to obtain ammonium salt solution, continue to raise the temperature to evaporate the solvent to facilitate the smooth progress of polycondensation reaction, heat up again and draw a vacuum to carry out polycondensation reaction, and after the reaction is completed, polyester elastomer is obtained.

[0019] In this step, diacid II and solvent are added, and at low temperature, the terminal carboxyl group of diacid II reacts with the terminal amino group of the multi-component oligomer to form a salt. Then, at high temperature, three forms of bonding condensation reactions are carried out simultaneously: ammonium salt dehydration to form amide bonds, dehydration of terminal carboxyl groups and terminal hydroxyl groups to form ester bonds, and dehydration of terminal hydroxyl groups to form ester bonds, to prepare multi-block polyester elastomer.

[0020] In the method of this invention, based on the priority of the low-temperature salt formation reaction between the terminal carboxyl group and the terminal amino group, the terminal amino group is directionally sealed with dicarboxylic acid II to form amide bonds, which ensures the continuous chain growth reaction and efficiently and controllably introduces polyamide segments into the molecular chain, thus preparing a thermoplastic polyester elastomer containing polyether segments, polyamide segments, and polyester backbone. The high crystallinity and mechanical properties of the polyamide segments are used to supplement the deficiencies of the hard segments of the polyester elastomer, strengthen hydrogen bond interactions, and improve elastic recovery performance.

[0021] In the preparation method described above, the molar ratio of hydroxyl to carboxyl groups in the total amount of dicarboxylic acid I, diol and hydroxyl-terminated polyether in step (1) is 1.2~1.5:1;

[0022] The dicarboxylic acid I is selected from at least one of terephthalic acid, 2,6-naphthalenedicarboxylic acid or isophthalic acid;

[0023] The diol is selected from at least one of ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, or 1,6-hexanediol; the hydroxyl-terminated polyether is selected from at least one of polyethylene glycol, polypropylene glycol, or polytetrahydrofuran; and the molecular weight of the hydroxyl-terminated polyether is 1000~4000 g / mol.

[0024] The preparation method described herein, in step (1), the conditions for vacuuming and heating are as follows: the vacuum degree is made to reach below 500 Pa at 0.5~1.0 h, and the temperature is raised to 220~240℃;

[0025] The transesterification reaction takes 0.3-0.6 h;

[0026] The conditions for the esterification reaction are: esterification temperature 200~240℃, and esterification is terminated when the water content is ≥90%.

[0027] The polyether component in the polyester oligomer accounts for 20-50 wt% of the polyester oligomer.

[0028] In the preparation method described above, the catalyst in step (1) is selected from at least one of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, tetrabutyl zirconate, antimony glycolate, antimony trioxide, zinc acetate, zinc oxide, or germanium oxide; the amount of catalyst added is 100 to 1000 ppm of the total mass of dicarboxylic acid I, diol, and hydroxyl-terminated polyether.

[0029] Antioxidants and heat stabilizers are also added along with the catalyst.

[0030] The antioxidant is selected from at least one of antioxidant 1010, antioxidant 1076 or antioxidant 3114; the amount of antioxidant added is 50 to 100 ppm of the total mass of diacid I, diol and hydroxyl-terminated polyether.

[0031] The heat stabilizer is selected from at least one of triphenyl phosphate, triphenyl phosphite, or trimethyl phosphite; the amount of the heat stabilizer added is 50-100 ppm of the total mass of dicarboxylic acid I, diol, and hydroxyl-terminated polyether.

[0032] In the preparation method described above, the caprolactam aqueous solution in step (2) contains 1-3 wt% water relative to the mass of caprolactam; the mass of the caprolactam aqueous solution is 3-15 wt% of the polyester oligomer.

[0033] The heating and melting temperature is 80~90℃;

[0034] The conditions for the hydrolysis ring-opening reaction are: temperature 220~240℃, pressure 0.4~0.6MPa, and time 1.5~3.0h;

[0035] The esterification reaction is carried out under the following conditions: pressure 0.2~0.4MPa, temperature 230~250℃, and time 1~2h.

[0036] In the preparation method described above, the solvent in step (3) is one of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide;

[0037] The mass of the solvent is 0.9 to 1.2 times the total mass of the multi-component oligomer and dicarboxylic acid II;

[0038] The temperature is raised to 70-90℃; the salt formation reaction takes 0.5-1 hour.

[0039] The temperature is then further increased to 200-240℃;

[0040] The conditions for the polycondensation reaction are: temperature 250~290℃, vacuum degree less than or equal to 100Pa, and time 2~4h.

[0041] In the preparation method described above, the dicarboxylic acid II in step (3) is selected from at least one of succinic acid, adipic acid, octanoic acid, or sebacic acid;

[0042] The molar ratio of the dicarboxylic acid II to the caprolactam in step (2) is 0.4~0.8:1;

[0043] Secondly, the present invention provides a multiphase synergistic high-strength and high-elasticity polyester elastomer, obtained by any of the preparation methods described herein.

[0044] The multiphase synergistic high-strength and high-elasticity polyester elastomer described above has the following properties: intrinsic viscosity ≥ 0.85 dL / g, molecular weight distribution index ≤ 2.3, color value b ≤ 6, and notched impact strength ≥ 8 KJ / m. 2 Tensile yield stress ≥40MPa, tensile elastic modulus ≥200MPa, tensile fracture strain ≥700%, elastic recovery rate at 100% constant elongation ≥88%.

[0045] Thirdly, the present invention provides the application of the described polyester elastomer, or the polyester elastomer obtained by any of the preparation methods described, as a thermoplastic polyester elastomer in the automotive industry, medical and health care, electronics and electrical appliances and flexible packaging.

[0046] Definitions:

[0047] The hydroxyl-terminated polyethers described in this invention refer to polyether polymers whose molecular chains are capped with hydroxyl groups at both ends.

[0048] The first and second reaction vessels of the present invention are selected from reaction vessels or other containers that can provide a reaction site under high temperature and high pressure.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) Based on the priority of the salt formation reaction between the terminal carboxyl group and the terminal amino group at low temperature, the present invention designs a synthetic route, and then raises the temperature to dehydrate the ammonium salt to form an amide bond, and directionally seals the terminal amino group of the diacid to ensure that the reaction between the diacid and the terminal amino group proceeds efficiently and promotes the continuous chain growth reaction. A high-strength and high-elasticity polyester elastomer containing polyamide segments, polyether segments and polyester backbone was successfully prepared. This method is applicable to a variety of polyester systems and broadens the synthetic route of polyester elastomer.

[0051] (2) This invention introduces polyamide segments with high crystallinity as a second hard segment into the polyester elastomer chain, thereby enhancing the crystallinity of the elastomer and improving the tensile breaking strength, tensile modulus, and elastic recovery rate of the elastomer by strengthening the intermolecular hydrogen bond interactions. This simultaneously improves the tensile strength, tensile modulus, and elastic properties of the polyester elastomer.

[0052] (3) This invention designs molecular chain structure through copolymerization modification and prepares high-performance polyester elastomer with multiple microphase structure formed by two hard segments and one soft segment. Unlike blending modification, this method solves the compatibility problem between different materials and is more conducive to melt processing and molding.

[0053] (4) The multiphase synergistic high-strength and high-elasticity polyester elastomer of the present invention has excellent properties, with intrinsic viscosity ≥0.85dL / g, molecular weight distribution index ≤2.3, color value b≤6, and notched impact strength ≥8KJ / m. 2 Tensile yield stress ≥40MPa, tensile elastic modulus ≥200MPa, tensile fracture strain ≥700%, elastic recovery rate at 100% constant elongation ≥88%.

[0054] (5) The present invention designs a two-reactor process with polyester components as the main body, which can continuously prepare polyester elastomers. A novel technical route is adopted to construct polyamide segment-reinforced polyether ester elastomers in a stepwise and orderly manner. This technical route effectively ensures that the molecular chain sequence structure presents a multi-block copolymer form with three segment structures. The diacid forms amide bonds through salt formation reaction with the terminal amino group. The reaction is mild, orderly and highly active. In this process, the diacid has little effect on the acid-catalyzed degradation of polyester oligomers. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the synthesis route of the polyester elastomer of the present invention. Detailed Implementation

[0056] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0057] The testing methods involved in the performance indicators of this invention are as follows:

[0058] 1. Molecular weight distribution index: Gel permeation chromatography (GPC, Agilent 1260 Infinity II) was used to test the molecular weight distribution index. A standard curve was established using polymethyl methacrylate (manufacturer: Agilent, brand name: PL20229001) as a standard. Hexafluoroisopropanol was used as the solvent and the mobile phase flow rate was 1 mL / min.

[0059] 2. Intrinsic viscosity: According to standard GB / T 14190-2008, phenol / 1,1,2,2-tetrachloroethane (mass ratio 1:1) was used as solvent and tested in a water bath at 25°C using an Ubbelohde viscometer.

[0060] 3. Tensile yield stress, tensile modulus of elasticity and tensile fracture strain: tested according to national standard GB / T 1040.1-2025.

[0061] 4. Notched impact strength: The impact strength of the specimen was tested using a pendulum impact tester in accordance with GB / T 1843—2008 "Determination of impact strength of plastic cantilever beam".

[0062] 5. Elastic recovery rate: Tested on a universal testing machine (Instron 5969). The specimen was prepared by injection molding and its size was 150 mm × 10 mm × 4 mm. The specimen was stretched at a constant speed of 50 mm / min to a constant deformation of 100%. The whole process was repeated 5 times. Each cycle included the stretching process and the recovery process.

[0063] 6. Color value b: Tested using a spectrophotometer (S81, TOOLSO, Chain), with a light wavelength of 370~760nm.

[0064] When the diacid I in the preparation method of this invention is selected from terephthalic acid, the diol is selected from ethylene glycol, and the hydroxyl-terminated polyether is selected from polytetrahydrofuran, the schematic diagram of the synthesis route of the polyester elastomer of this invention is as follows: Figure 1 As shown, m, n, x, q, and a are integers, where m is 7~30, n is 14~56, x is 1~3, q is 2~10, and a is 3~6.

[0065] Example 1:

[0066] (1) 1494g of terephthalic acid, 670g of ethylene glycol and 741g of polytetrahydrofuran (number average molecular weight 2000g / mol) were placed in polymerization reactor I (5L), and 0.58g of antimony glycolate, 0.29g of antioxidant 1010 and 0.29g of triphenyl phosphate were added to carry out esterification reaction. The esterification temperature was 230℃ and the esterification reaction ended when the water content was ≥90%. The vacuum was gradually evacuated to achieve an absolute vacuum of less than 500Pa in 0.7h, and the temperature was gradually increased to 240℃. The reaction was continued for 0.3h to obtain a polyester oligomer with polyether component (1728g of polyester component, 741g of polyether component, total 2469g), in which the polyether content was about 30wt% of the polyester oligomer mass.

[0067] (2) Caprolactam containing 3 wt% (relative to the mass of the polyester oligomer) of water was heated to melt at 80°C and added to reactor I at 10 wt% (caprolactam mass 247 g, about 2.19 mol) relative to the mass of the polyester oligomer. The mixture was thoroughly mixed with the polyester oligomer melt and the temperature was maintained at 240°C. The hydrolysis and ring-opening reaction of caprolactam was carried out at 0.6 MPa for 3.0 h. Then the pressure was slowly released to 0.4 MPa and the esterification reaction was carried out at 250°C for 2 h. Finally, a multi-component oligomer with terminal amino and terminal hydroxyl groups was prepared.

[0068] (3) Add the multi-component oligomer with terminal amino and terminal hydroxyl groups (2469g+247g=2716g), 192g adipic acid (2.19*0.6=1.314mol) and 2869g solvent N,N-dimethylformamide to reactor II (10L); raise the solution temperature to 90℃, turn on the stir to dissolve the reactants completely, react for 0.5h to obtain an ammonium salt solution; then raise the reaction temperature to 240℃ to completely evaporate and collect the solvent, raise the reaction temperature to 290℃, gradually evacuate the vacuum to below 100Pa, polycondensation reaction for 4h, the reaction ends, discharge and pelletize to obtain polyester elastomer.

[0069] The polyester elastomer has an intrinsic viscosity of 0.85 dL / g, a molecular weight distribution index of 2.1, a color value (b) of 6, and a notched impact strength of 9 KJ / m. 2 The tensile yield stress is 55 MPa, the tensile elastic modulus is 280 MPa, the tensile fracture strain is 700%, and the elastic recovery rate at 100% constant elongation is 88%.

[0070] Example 2:

[0071] (1) 1494g of terephthalic acid, 781g of 1,3-propanediol and 795g of polyethylene glycol (number average molecular weight 1000g / mol) were placed in polymerization reactor I (5L), and 0.30g of tetrabutyl titanate, 0.15g of antioxidant 1076 and 0.15g of triphenyl phosphite were added to carry out esterification reaction. The esterification temperature was 200℃ and the esterification reaction ended when the water content was ≥90%. The vacuum was gradually evacuated to achieve an absolute vacuum of less than 500Pa in 0.5h, and the temperature was gradually increased to 220℃. The reaction was continued for 0.4h to obtain a polyester oligomer with polyether component (1854g of polyester component, 795g of polyether component, total 2649g), in which the polyether content was about 30wt% of the polyester oligomer mass.

[0072] (2) Caprolactam containing 1 wt% (relative to the mass of the polyester oligomer) of water was heated to melt at 85°C, and 5 wt% (caprolactam mass 132 g, about 1.16 mol) relative to the mass of the polyester oligomer was added to reactor I and thoroughly mixed with the polyester oligomer melt. The temperature was maintained at 220°C and 0.4 MPa for the hydrolysis and ring-opening reaction of caprolactam for 1.5 h. Then the pressure was slowly released to 0.2 MPa and the esterification reaction was carried out at 230°C for 1 h. Finally, a multi-component oligomer with terminal amino and terminal hydroxyl groups was prepared.

[0073] (3) The above-mentioned multi-component oligomer with terminal amino and terminal hydroxyl groups (2649g+132g=2781g), 55g succinic acid (1.16*0.4=0.464mol) and 2552.4g ((2781g+55g)*0.9) N,N-dimethylacetamide) were added to reactor II (10L); the solution temperature was raised to 70℃, the stirring was turned on to dissolve the reactants completely, and the reaction was carried out for 1h to obtain an ammonium salt solution; then the reaction temperature was raised to 200℃ to completely evaporate and collect the solvent, and the reaction temperature was raised to 250℃, and the vacuum was gradually drawn until the vacuum degree reached below 100Pa. The polycondensation reaction was carried out for 2h, the reaction was completed, and the material was discharged and granulated to obtain polyester elastomer.

[0074] The polyester elastomer has an intrinsic viscosity of 0.9 dL / g, a molecular weight distribution index of 2.0, a color value (b) of 5, and a notched impact strength of 11 KJ / m. 2 The tensile yield stress is 53 MPa, the tensile elastic modulus is 320 MPa, the tensile fracture strain is 720%, and the elastic recovery rate at 100% constant elongation is 89%.

[0075] Example 3:

[0076] (1) 1494g of terephthalic acid, 900g of 1,4-butanediol and 849g of polypropylene glycol (number average molecular weight 3000g / mol) were placed in polymerization reactor I (5L), and 0.32g of zinc acetate, 0.16g of antioxidant 3114 and 0.16g of trimethyl phosphite were added to carry out esterification reaction. The esterification temperature was 240℃, and the esterification reaction ended when the water content was ≥90%. The vacuum was gradually evacuated to achieve an absolute vacuum of less than 500Pa in 1.0h, and the temperature was gradually increased to 230℃. The reaction was continued for 0.6h to obtain a polyester oligomer with polyether component (1980g of polyester component, 849g of polyether component, total 2829g), in which the polyether content was about 30wt% of the polyester oligomer mass.

[0077] (2) Caprolactam containing 2 wt% (relative to the mass of the polyester oligomer) of water was heated to melt at 90°C and added to reactor I at 15 wt% (caprolactam mass 424 g, about 3.75 mol) relative to the mass of the polyester oligomer. The mixture was thoroughly mixed with the polyester oligomer melt and the temperature was maintained at 230°C. The hydrolysis and ring-opening reaction of caprolactam was carried out at 0.5 MPa for 2.0 h. Then the pressure was slowly released to 0.3 MPa and the esterification reaction was carried out at 240°C for 1.4 h. Finally, a multi-component oligomer with terminal amino and terminal hydroxyl groups was prepared.

[0078] (3) Add the multi-component oligomer with terminal amino and terminal hydroxyl groups (2829g+424g=3253g), 522g of octanoic acid (3.75*0.8=3mol) and 3398g of ((3253g+522g)*0.9) dimethyl sulfoxide to reactor II (10L); raise the solution temperature to 80℃, turn on the stir to dissolve the reactants completely, react for 0.7h to obtain an ammonium salt solution; then raise the reaction temperature to 220℃ to completely evaporate and collect the solvent, raise the reaction temperature to 280℃, gradually evacuate the vacuum to below 100Pa, polycondensation reaction for 3h, the reaction ends, discharge and pelletize to obtain polyester elastomer.

[0079] The polyester elastomer has an intrinsic viscosity of 0.9 dL / g, a molecular weight distribution index of 1.9, a color value (b) of 4, and a notched impact strength of 12 KJ / m. 2 The tensile yield stress is 50 MPa, the tensile elastic modulus is 335 MPa, the tensile fracture strain is 810%, and the elastic recovery rate at 100% constant elongation is 90%.

[0080] Example 4:

[0081] (1) 1296g of 2,6-naphthalenedicarboxylic acid, 434g of ethylene glycol and 1452g of polytetrahydrofuran (number average molecular weight 2000g / mol) were placed in polymerization reactor I (5L), and 0.31g of antimony trioxide, 0.19g of antioxidant 1010 and 0.19g of triphenyl phosphate were added to carry out esterification reaction. The esterification temperature was 230℃. The esterification reaction was terminated when the water content was ≥90%. The vacuum was gradually evacuated to achieve an absolute vacuum of less than 500Pa in 0.7h, and the temperature was gradually increased to 240℃. The reaction was continued for 0.3h to obtain a polyester oligomer with polyether component (1452g polyester component, 1452g polyether component, total 2904g), in which the polyether content was about 50wt% of the polyester oligomer mass.

[0082] (2) Caprolactam containing 2 wt% (relative to the mass of the polyester oligomer) of water was heated to melt at 80°C and added to reactor I at 10 wt% (caprolactam mass 290 g, about 2.57 mol) relative to the mass of the polyester oligomer. The mixture was thoroughly mixed with the polyester oligomer melt and the temperature was maintained at 240°C. The hydrolysis and ring-opening reaction of caprolactam was carried out at 0.6 MPa for 3.0 h. Then the pressure was slowly released to 0.4 MPa and the esterification reaction was carried out at 250°C for 2 h. Finally, a multi-component oligomer with terminal amino and terminal hydroxyl groups was prepared.

[0083] (3) Add the multi-component oligomer with terminal amino and terminal hydroxyl groups (2904g+290g=3194g), 311g sebacic acid (2.57*0.6=1.54mol) and 3505g (3194g+311g) N,N-dimethylformamide to reactor II (10L); raise the solution temperature to 90℃, turn on the stir to dissolve the reactants completely, react for 0.5h to obtain an ammonium salt solution; then raise the reaction temperature to 240℃ to completely evaporate and collect the solvent, raise the reaction temperature to 290℃, gradually evacuate the vacuum to below 100Pa, polycondensation reaction for 4h, the reaction ends, discharge and granulate to obtain polyester elastomer.

[0084] The polyester elastomer has an intrinsic viscosity of 1.05 dL / g, a molecular weight distribution index of 1.8, a color value (b) of 5.1, and a notched impact strength of 8 KJ / m. 2 The tensile yield stress is 50 MPa, the tensile elastic modulus is 324 MPa, the tensile fracture strain is 760%, and the elastic recovery rate at 100% constant elongation is 92%.

[0085] Example 5:

[0086] (1) 1328g isophthalic acid, 558g ethylene glycol and 384g polyethylene glycol (number average molecular weight 4000g / mol) were placed in polymerization reactor I (5L), and 0.89g germanium oxide, 0.13g antioxidant 1010 and 0.13g triphenyl phosphate were added to carry out esterification reaction. The esterification temperature was 230℃ and the esterification reaction ended when the water content was ≥90%. The vacuum was gradually evacuated to make the absolute vacuum degree reach below 500Pa in 0.7 h, and the temperature was gradually raised to 240℃. The reaction was continued for 0.3 h to obtain a polyester oligomer with polyether component (1536g polyester component, 384g polyether component, total 1920g), in which the polyether content was about 20wt% of the polyester oligomer mass.

[0087] (2) Caprolactam containing 3 wt% (relative to the mass of the polyester oligomer) of water was heated to melt at 80°C and added to reactor I at 10 wt% (caprolactam mass 192 g, about 1.7 mol) relative to the mass of the polyester oligomer. The mixture was thoroughly mixed with the polyester oligomer melt and the temperature was maintained at 240°C and 0.6 MPa for 3.0 h. Then the pressure was slowly released to 0.4 MPa and the esterification reaction was carried out at 250°C for 2 h. Finally, a multi-component oligomer with terminal amino and terminal hydroxyl groups was prepared.

[0088] (3) Add the multi-component oligomer with terminal amino and terminal hydroxyl groups (1920g+192g=2112g), 149g adipic acid (1.7*0.6=1.02mol) and 2713g ((2112g+149g)*1.2)N,N-dimethylacetamide) to reactor II (10L); raise the solution temperature to 90℃, turn on the stir to dissolve the reactants completely, react for 0.5h to obtain an ammonium salt solution; then raise the reaction temperature to 240℃ to completely evaporate and collect the solvent, raise the reaction temperature to 290℃, gradually evacuate the vacuum to below 100Pa, polycondensation reaction for 4h, the reaction ends, discharge and granulate to obtain polyester elastomer.

[0089] The polyester elastomer has an intrinsic viscosity of 0.90 dL / g, a molecular weight distribution index of 2.0, a color value (b) of 4, and a notched impact strength of 16 KJ / m. 2 The tensile yield stress is 50 MPa, the tensile elastic modulus is 290 MPa, the tensile fracture strain is 710%, and the elastic recovery rate at 100% constant elongation is 88%.

[0090] Comparative Example 1:

[0091] (1) Place 1000g caprolactam, 152g capping agent adipic acid and 50g water in polymerization reactor I (5L), heat to 250℃, and react for 3 h under a pressure of 1.5MPa; after depressurization, gradually evacuate for 2 h to a pressure below 700Pa, and after discharge and drying, obtain dicarboxylic acid-capped polyamide oligomer.

[0092] (2) The polyamide oligomer with diacid end caps was prepared and 400g of methanol was placed in polymerization reactor I (5L) and heated to 220°C. The transesterification reaction was carried out at a pressure of 1MPa for 3 h. After drying, the polyester amide oligomer with ester end groups was obtained.

[0093] (3) The polyester amide oligomer with ester end groups, 1000g of dimethyl terephthalate, 1120g of 1,4-butanediol and 5g of antimony glycol were placed in polymerization reactor I (5L) and heated to 210℃ for atmospheric pressure transesterification reaction for 4 h to obtain polyester amide oligomer with hydroxyl end groups.

[0094] (4) The polyester amide oligomer with hydroxyl end groups was subjected to polycondensation reaction with polytetrahydrofuran. The mixture was slowly vacuumed to below 100 Pa at 250°C and kept for 4 h. The product was then discharged and pelletized to obtain polyester amide elastomer.

[0095] The intrinsic viscosity of the polyesteramide elastomer is 0.85 dL / g, the molecular weight distribution index is 2.3, the color value (b) is 6.5, and the notched impact strength is 15 KJ / m. 2 The tensile yield stress is 40 MPa, the tensile elastic modulus is 260 MPa, the tensile fracture strain is 360%, and the elastic recovery rate at 100% constant elongation is 85%.

[0096] Comparative Example 2:

[0097] (1) Place 1328g of terephthalic acid, 645g of ethylene glycol and 1.5g of antimony glycol catalyst in polymerization reactor I (5L), heat to 230℃, and carry out esterification reaction. The esterification reaction ends when the water content is ≥90%.

[0098] (2) Then add 658g of polytetrahydrofuran for polycondensation reaction, and slowly vacuum the material at 250°C to below 100Pa for 4 hours. The material is then discharged and pelletized to obtain polyester elastomer.

[0099] The polyester elastomer has an intrinsic viscosity of 0.83 dL / g, a molecular weight distribution index of 2.1, a color value (b) of 4, and a notched impact strength of 10 KJ / m. 2 The tensile yield stress is 30 MPa, the tensile elastic modulus is 150 MPa, the tensile fracture strain is 410%, and the elastic recovery rate at 100% constant elongation is 61%.

[0100] Comparative Example 3:

[0101] (1) Place 1000g caprolactam, 146g adipic acid and 50g water in polymerization reactor I (5L), heat to 250℃, and react for 3 h under a pressure of 1.5MPa; after depressurization, gradually evacuate for 2 h to a pressure below 700Pa to obtain dicarboxylic acid-terminated polyamide oligomer.

[0102] (2) Then add 400g of polytetrahydrofuran for polycondensation reaction, and slowly vacuum the material at 250℃ to below 100Pa for 4 hours. The material is then discharged and pelletized to obtain polyamide elastomer.

[0103] The polyamide elastomer has a relative viscosity of 2.6 dL / g (there is no intrinsic viscosity standard for polyamide, only relative viscosity can be used), a molecular weight distribution index of 2.2, a color value b of 5, and a notched impact strength of 30 KJ / m. 2 The tensile yield stress is 55 MPa, the tensile elastic modulus is 350 MPa, the tensile fracture strain is 650%, and the elastic recovery rate at 100% constant elongation is 93%.

[0104] In summary, the multiphase polyester elastomers prepared by the method of this invention exhibit excellent overall performance.

Claims

1. A method for preparing a multiphase synergistic high-strength and high-elasticity polyester elastomer, characterized in that, Includes the following steps: (1) Weigh out dicarboxylic acid I, diol and hydroxyl-terminated polyether and add them to the first reaction vessel. Add catalyst and carry out esterification reaction. After vacuuming and heating, carry out transesterification reaction to obtain polyester oligomer containing polyether component. (2) Weigh caprolactam aqueous solution, heat and melt it and add it to the first reaction vessel. Mix it evenly with the polyester oligomer obtained above, carry out the hydrolysis and ring-opening reaction of caprolactam under pressure, and carry out the esterification reaction after slowly depressurizing to obtain a multi-component oligomer with terminal amino and terminal hydroxyl groups. (3) Weigh the above-mentioned multi-component oligomer with terminal amino and terminal hydroxyl groups, dicarboxylic acid II and solvent into the second reaction vessel, heat up and stir to dissolve, carry out salt formation reaction to obtain ammonium salt solution, continue to raise the temperature to evaporate the solvent, heat up again and vacuum to carry out polycondensation reaction, and after the reaction is completed, polyester elastomer is obtained. The dicarboxylic acid I is selected from at least one of terephthalic acid, 2,6-naphthalenedicarboxylic acid or isophthalic acid; The diol is selected from at least one of ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, or 1,6-hexanediol; The hydroxyl-terminated polyether is selected from at least one of polyethylene glycol, polypropylene glycol, or polytetrahydrofuran; The molar ratio of hydroxyl to carboxyl groups in the total amount of dicarboxylic acid I, diol, and hydroxyl-terminated polyether is 1.2~1.5:1; The dicarboxylic acid II is selected from at least one of succinic acid, adipic acid, octanoic acid, or sebacic acid; The molar ratio of the dicarboxylic acid II to the caprolactam in step (2) is 0.4~0.8:1; In the polyester oligomer containing polyether components, the polyether components account for 20-50% of the polyester oligomer. wt % The caprolactam aqueous solution contains 1-3% of the oligomer content relative to the polyester. wt % water; the mass of the caprolactam aqueous solution is 3-15% of the polyester oligomer mass. wt %.

2. The preparation method according to claim 1, characterized in that, The number-average molecular weight of the hydroxyl-terminated polyether in step (1) is 1000~4000 g / mol; The catalyst is selected from at least one of tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, tetrabutyl zirconate, antimony glycolate, antimony trioxide, zinc acetate, zinc oxide, or germanium oxide; the amount of the catalyst added is 100 to 1000 ppm of the total mass of dicarboxylic acid I, diol, and hydroxyl-terminated polyether.

3. The preparation method according to claim 1, characterized in that, The conditions for the esterification reaction in step (1) are: esterification temperature 200~240℃, and the esterification reaction ends when the water content is ≥90%; The conditions for evacuation and heating are: to achieve a vacuum level below 500 Pa at 0.5~1.0 h, and to heat to 220~240℃; The transesterification reaction takes 0.3-0.6 h.

4. The preparation method according to claim 1, characterized in that, In step (1), antioxidants and heat stabilizers are added along with the catalyst. The antioxidant is selected from at least one of antioxidant 1010, antioxidant 1076 or antioxidant 3114; the amount of antioxidant added is 50 to 100 ppm of the total mass of diacid I, diol and hydroxyl-terminated polyether. The heat stabilizer is selected from at least one of triphenyl phosphate, triphenyl phosphite, or trimethyl phosphite; the amount of the heat stabilizer added is 50-100 ppm of the total mass of dicarboxylic acid I, diol, and hydroxyl-terminated polyether.

5. The preparation method according to claim 1, characterized in that, The heating and melting temperature in step (2) is 80~90℃; The conditions for the hydrolysis ring-opening reaction are: temperature 220~240℃, pressure 0.4~0.6MPa, and time 1.5~3.0h; The esterification reaction is carried out under the following conditions: pressure 0.2~0.4MPa, temperature 230~250℃, and time 1~2h.

6. The preparation method according to claim 1, characterized in that, The solvent mentioned in step (3) is one of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; The mass of the solvent is 0.9 to 1.2 times the total mass of the multi-component oligomer and dicarboxylic acid II; The temperature is raised to 70-90℃; the salt formation reaction takes 0.5-1 hour. The temperature is then further increased to 200-240℃; The conditions for the polycondensation reaction are: temperature 250~290℃, vacuum degree less than or equal to 100Pa, and time 2~4h.

7. A multiphase synergistic high-strength, high-elasticity polyester elastomer, characterized in that, Obtained by the preparation method as described in any one of claims 1-6.

8. The multiphase synergistic high-strength and high-elasticity polyester elastomer as described in claim 7, characterized in that, The high-strength, high-elasticity polyester elastomer has an intrinsic viscosity ≥ 0.85 dL / g, a molecular weight distribution index ≤ 2.3, a color value b ≤ 6, and a notched impact strength ≥ 8 KJ / m. 2 Tensile yield stress ≥40MPa, tensile elastic modulus ≥200MPa, tensile fracture strain ≥700%, elastic recovery rate at 100% constant elongation ≥88%.

9. The application of the polyester elastomer as described in claim 7 or 8 as a thermoplastic polyester elastomer in the automotive industry, electronics and electrical appliances and flexible packaging.

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