Polyamide elastomer with high gas barrier property and high resilience and preparation method thereof

Abstract

The present application provides a polyamide elastomer with high gas barrier properties and high resilience and a preparation method thereof, which belongs to the technical field of polyamide elastomer preparation. Among them, the preparation method of the polyamide elastomer comprises: mixing cyclic lactam with water, and performing a ring-opening reaction after heating; then adding a predetermined amount of diamine and furandicarboxylic acid, performing a prepolymerization reaction, and obtaining a prepolymer; then mixing the prepolymer with diisocyanate and polyether diol, and performing a chain extension reaction to obtain a polyamide elastomer. In the above manner, the polyamide elastomer prepared based on the preparation method provided by the present application has high toughness, high resilience and good gas barrier properties, which can effectively expand the application field of polyamide elastomer and improve its added value. And the preparation method provided by the present application has a simple process, is easy to control, has a low cost, and has a high practical application value.

Description

Technical Field

[0001] The invention relates to the technical field of polyamide elastomer preparation, and in particular to a polyamide elastomer with high gas barrier properties and high resilience and a preparation method thereof. Background Art

[0002] Aliphatic polyamide (PA), commonly known as nylon, refers to the general term for thermoplastic resins containing repeated amide groups (-NHCO-) ​​on the main chain of the molecule. Its outstanding advantages are high mechanical strength, good wear resistance, good hydrophilicity, excellent processability, etc. It is widely used in textiles and clothing, medical equipment, electronic appliances, food packaging, automotive parts and other fields. Thermoplastic polyamide elastomer (TPAE) is an important variety of nylon material, with the dual characteristics of rubber and plastic. Compared with the widely used polystyrene thermoplastic elastomer (SBC), polyolefin elastomer (TPO), polyurethane thermoplastic elastomer (TPU) and polyester thermoplastic elastomer (TPEE), TPAE is a new member of the thermoplastic elastomer family, and its preparation and application started relatively late. However, due to its excellent comprehensive performance, it has become a rapidly developing elastomer material.

[0003] Existing polyamide elastomer products are generally produced by block copolymerization with long carbon chain nylon as hard segment and ether as soft segment. Common polyamide elastomers are copolymerized by nylon 12 or nylon 11 and polyether polyols. Commercial products include Pebax XX33 series products of Arkema in France, Vestamid E series products of Envonik in Germany, and UPAE series products of Xinyuan Technology in China. The commonly used synthesis method generally adopts polycondensation reaction. The molecular weight of the synthesized polyamide elastomer is not high, and the mechanical properties need to be further improved. In addition, the compression permanent deformation rate of polyamide elastomer is large. It is difficult to restore the original state after compression deformation. The resilience is poor, and it does not have excellent gas barrier properties. In addition, the cost of nylon 12 or nylon 11 hard segments is high. It is urgent to develop a low-cost polyamide elastomer with excellent comprehensive performance, which is of great significance for breaking the international monopoly, expanding the application scope of polyamide elastomers, and increasing their added value.

[0004] In the prior art, the patent with publication number CN116396484A provides a high molecular weight polyamide elastomer containing triazine rings and a preparation method thereof. The patent uses cyanuric chloride as a chain extender and polyether as a soft segment, and prepares the high molecular weight polyamide elastomer by a substitution reaction of a polyamide elastomer prepolymer and cyanuric chloride. However, the resilience performance of the elastomer formed in this way still needs to be improved, and its barrier performance is poor.

[0005] In view of this, in order to further expand the application field of nylon elastomers and improve their comprehensive performance, it is necessary to design a polyamide elastomer with high gas barrier properties and high resilience and a preparation method thereof to solve the above problems. Summary of the invention

[0006] In view of the technical problems existing in the background technology, the present application provides a polyamide elastomer with high gas barrier properties and high resilience and a preparation method thereof, aiming to solve the technical problem that the existing polyamide elastomer is difficult to have high gas barrier properties and high resilience at the same time.

[0007] In a first aspect, the present invention provides a method for preparing a polyamide elastomer having high gas barrier properties and high resilience, comprising the following steps:

[0008] S1. The cyclic lactam is mixed with water and heated to perform a ring-opening reaction; then a predetermined amount of a diamine and furan dicarboxylic acid are added to perform a prepolymerization reaction to obtain a prepolymer;

[0009] S2. The prepolymer is mixed with diisocyanate and polyether diol to carry out a chain extension reaction to obtain a polyamide elastomer.

[0010] In the technical scheme of the embodiment of the present application, the cyclic lactam ring-opening reaction speed is fast, the reaction efficiency is high, the monomer ratio is easy to control, and the cost is low. The present application is to open the cyclic lactam and then perform prepolymerization with diamine and furandicarboxylic acid, so that the generated oligomer prepolymer is used as the hard segment of the nylon elastomer, which is conducive to accurately controlling the chemical structure of the elastomer, obtaining a nylon elastomer material with excellent performance, and reducing its production cost, which is more conducive to promotion and application. In addition, the present application introduces furandicarboxylic acid as a comonomer in the prepolymerization reaction, which can make the subsequently obtained polyamide elastomer have higher gas barrier properties. On this basis, by regulating the amount of furandicarboxylic acid, it is also conducive to improving the strength and toughness of the polyamide elastomer, and combined with the ratio regulation of the soft and hard segments, the obtained polyamide elastomer can have high resilience.

[0011] In some embodiments, in step S1, the mass volume ratio of the cyclic lactam to water is 40-60 g:1 mL, and the temperature of the ring-opening reaction is 240-260°C.

[0012] In this embodiment, the ring-opening reaction of the cyclic lactam can be carried out quickly, and the diamine and furandicarboxylic acid can be added for prepolymerization after two and a half hours, and the reaction efficiency is relatively high.

[0013] In some embodiments, in step S1, the mass ratio of the cyclic lactam, the diamine and the furandicarboxylic acid is 50:0.8-1.2:0.25-1.

[0014] In this embodiment, a specific proportion of furandicarboxylic acid can be introduced, which not only endows the polyamide elastomer with high gas barrier performance, but also helps to improve the strength, toughness and high resilience of the polyamide elastomer.

[0015] In some embodiments, in step S1, the temperature of the prepolymerization reaction is 240 - 260 °C, and the reaction time is 30 - 40 min.

[0016] In this embodiment, the ring-opened cyclic lactam can react with diamine and furandicarboxylic acid to form a prepolymer.

[0017] In some embodiments, in step S2, the mass ratio of the prepolymer, the diisocyanate and the polyether diol is 50:0.8 - 1.2:1 - 3.

[0018] In this embodiment, by controlling the proportion of raw materials, the proportion of hard and soft segments can be effectively regulated, so that the prepared polyamide elastomer has good resilience.

[0019] In some embodiments, in step S2, the temperature of the chain extension reaction is 240 - 260 °C, and the reaction time is 30 - 40 min.

[0020] In this embodiment, the prepolymer can react fully with the diisocyanate and the polyether diol to form a polyamide elastomer.

[0021] In some embodiments, in step S2, the number-average molecular weight of the polyether diol is 1000 - 5000 g / mol.

[0022] In this embodiment, the polyether diol with a specific number-average molecular weight is beneficial to improving the resilience and other mechanical properties of the polyamide elastomer.

[0023] In some embodiments, in step S2, the diisocyanate is at least one of diphenylmethane diisocyanate, toluene diisocyanate, and isophorone diisocyanate; the polyether diol is at least one of polytetrahydrofuran, polyethylene glycol, and polypropylene glycol.

[0024] In a second aspect, the embodiments of the present application provide a polyamide elastomer with high gas barrier property and high resilience. The polyamide elastomer is prepared by using any of the above preparation methods and includes hard segments and soft segments.

[0025] In some embodiments, the mass ratio of the hard segments to the soft segments in the polyamide elastomer is 2:98 - 10:90.

[0026] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic diagram of the synthesis route of a polyamide elastomer with high gas barrier properties and high resilience provided in an embodiment of the present application;

[0029] Figure 2 Schematic diagram of the molecular chain of polyamide elastomer;

[0030] Figure 3 The uniaxial tensile stress-strain curve of the polyamide elastomer prepared in Example 1;

[0031] Figure 4 This is a test curve of the one-cycle tensile resilience performance of the polyamide elastomer prepared in Example 1. DETAILED DESCRIPTION

[0032] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0034] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0035] Conventional preparation methods of polyamide elastomers generally utilize copolymerization of nylon 12 or nylon 11 and polyether polyols, but the cost of nylon 12 or nylon 11 is relatively high, and the obtained polyamide elastomer has a low molecular weight, mechanical properties need to be improved, and gas barrier properties are poor. In addition, this type of polyamide elastomer has a large compression permanent deformation rate, and it is difficult to restore the original state after compression deformation, and the resilience is poor, which limits the application of polyamide elastomers.

[0036] In order to solve the technical problems that the conventional preparation method of polyamide elastomer is high in cost and the obtained polyamide elastomer has poor gas barrier and resilience, the present application provides a polyamide elastomer with high gas barrier and high resilience and a preparation method thereof. The present application uses cyclic lactam, diamine, polyether diol, diisocyanate and furandicarboxylic acid as comonomers, reasonably designs its synthesis formula, and controls the relevant synthesis process to prepare a polyamide elastomer with high toughness, high resilience and good gas barrier, which effectively expands the application field of polyamide elastomer and improves its added value.

[0037] In a first aspect, the present invention provides a method for preparing a polyamide elastomer having high gas barrier properties and high resilience, comprising the following steps:

[0038] S1. The cyclic lactam is mixed with water and heated to perform a ring-opening reaction; then a predetermined amount of a diamine and furan dicarboxylic acid are added to perform a prepolymerization reaction to obtain a prepolymer;

[0039] S2. The prepolymer is mixed with diisocyanate and polyether diol to carry out a chain extension reaction to obtain a polyamide elastomer.

[0040] In the technical scheme of the embodiment of the present application, the cyclic lactam ring-opening reaction speed is fast, the reaction efficiency is high, the monomer ratio is easy to control, and the cost is low. The present application is to open the cyclic lactam and then perform prepolymerization with diamine and furandicarboxylic acid, so that the generated oligomer prepolymer is used as the hard segment of the nylon elastomer, which is conducive to accurately controlling the chemical structure of the elastomer, obtaining a nylon elastomer material with excellent performance, and reducing its production cost, which is more conducive to promotion and application. In addition, the present application introduces furandicarboxylic acid as a comonomer in the prepolymerization reaction, which can make the subsequently obtained polyamide elastomer have higher gas barrier properties. On this basis, by regulating the amount of furandicarboxylic acid, it is also conducive to improving the strength and toughness of the polyamide elastomer, and combined with the ratio regulation of the soft and hard segments, the obtained polyamide elastomer can have high resilience. In addition, urea bonds are introduced into the molecular chains of the polyamide elastomer synthesized in the embodiments of the present application, and the polymer chain bonds can form multiple double hydrogen bonds. The interaction force between the hard segment components of the polyamide elastomer is increased, and the molecular chains are arranged more closely, which can further improve the toughness and gas barrier properties of the polyamide elastomer.

[0041] Further, in some embodiments, in step S1, the mass volume ratio of the cyclic lactam to water is 40-60 g:1 mL, and the temperature of the ring-opening reaction is 240-260° C. More preferably, in some embodiments, the ring-opening reaction is carried out under the conditions of mechanical stirring and condensation reflux, and the speed of mechanical stirring is preferably 120-180 r / min.

[0042] In the technical solution of the embodiment of the present application, the ring-opening reaction of the cyclic lactam can be carried out quickly, and the diamine and furandicarboxylic acid can be added for prepolymerization reaction after two and a half hours, and the reaction efficiency is relatively high.

[0043] Furthermore, in some embodiments, in step S1, the mass ratio of the cyclic lactam, the diamine and the furandicarboxylic acid is 50:0.8-1.2:0.25-1.

[0044] In this embodiment, by introducing a specific proportion of furandicarboxylic acid, the polyamide elastomer is endowed with high gas barrier properties while also being beneficial for improving the toughness and resilience of the polyamide elastomer.

[0045] Furthermore, in some embodiments, in step S1, the temperature of the prepolymerization reaction is 240-260° C., and the reaction time is 30-40 min.

[0046] In this embodiment, the ring-opened cyclic lactam can be reacted with a diamine and furandicarboxylic acid to form a prepolymer.

[0047] Furthermore, in some embodiments, in step S1, the cyclic lactam is preferably caprolactam; and the diamine is preferably 1,6-hexanediamine.

[0048] Furthermore, in some embodiments, in step S2, the mass ratio of the prepolymer, the diisocyanate and the polyether diol is 50:0.8-1.2:1-3.

[0049] In this embodiment, by controlling the ratio of the raw materials, the ratio of the soft and hard segments can be effectively regulated, so that the prepared polyamide elastomer has good resilience.

[0050] Furthermore, in some embodiments, in step S2, the temperature of the chain extension reaction is 240-260° C., and the reaction time is 30-40 min.

[0051] In this embodiment, the prepolymer can be fully reacted with the diisocyanate and the polyether diol to form the polyamide elastomer.

[0052] Furthermore, in some embodiments, in step S2, the number average molecular weight of the polyether diol is 1000 to 5000 g / mol.

[0053] In this embodiment, the polyether diol with a specific number average molecular weight is beneficial to improving the resilience and other mechanical properties of the polyamide elastomer.

[0054] Furthermore, in some embodiments, in step S2, the diisocyanate is at least one of diphenylmethane diisocyanate, toluene diisocyanate, and isophorone diisocyanate, and more preferably diphenylmethane diisocyanate; the polyether diol is at least one of polytetrahydrofuran, polyethylene glycol, and polypropylene glycol, and more preferably polytetrahydrofuran.

[0055] Further, in some embodiments, in step S2, after the chain extension reaction, the speed of mechanical stirring is increased to 220-280r / min, the temperature is increased to 265-275°C, and the reaction system is vacuumed. When there is no obvious pole climbing phenomenon in the reaction bottle, the vacuuming operation is stopped, and the polyamide elastomer can be obtained after cooling and pelletizing. Among them, the vacuuming method is preferably to first extract a small vacuum for 2-4 minutes, and then fully vacuum for 1-3 minutes, the vacuum degree during the small vacuum extraction is -30--20kPa, and the vacuum degree during the full vacuum extraction is -85kPa--80kPa.

[0056] In the second aspect, the embodiment of the present application provides a polyamide elastomer with high gas barrier properties and high resilience, wherein the polyamide elastomer is prepared by any of the above-mentioned preparation methods, and comprises a hard segment and a soft segment, and its molecular chain schematic diagram is as shown in Figure 2 shown.

[0057] Furthermore, in some embodiments, the mass ratio of the hard segment to the soft segment in the polyamide elastomer is 2:98 to 10:90.

[0058] In the technical solution of the embodiment of the present application, the polyamide elastomer has high gas barrier properties and high resilience, and can be used in medical gas catheters, food packaging and other fields, effectively expanding the application field of conventional polyamide elastomers. The above preparation method is simple in process, easy to control, and low in cost, and has high practical application value.

[0059] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained commercially.

[0060] 1. Preparation method

[0061] Example 1

[0062] This embodiment provides a method for preparing a polyamide elastomer with high gas barrier properties and high resilience. The schematic diagram of its synthesis route is as follows: Figure 1 As shown, the specific steps include:

[0063] Weigh 50g of caprolactam into a three-necked flask, add 1mL of deionized water, raise the temperature of the heating mantle to 250°C, and carry out a ring-opening reaction under mechanical stirring at 150r / min and condensation reflux. After two and a half hours of reaction, keep the temperature of the heating mantle and the mechanical stirring rate unchanged, and add 1g of 1,6-hexanediamine and 0.25g of 2,5-furandicarboxylic acid to the three-necked flask to form a prepolymer. After continuing the reaction for half an hour, keeping the temperature of the heating jacket and the mechanical stirring rate unchanged, add 1g of diphenylmethane diisocyanate and 1g of polytetrahydrofuran (Mn=1000g / mol), and continue the reaction for half an hour, then increase the temperature of the heating jacket to 270°C, increase the mechanical stirring rate to 250r / min, and evacuate the reaction system, first with a small vacuum (vacuum degree of -25kPa) for 3min, and then with a full vacuum (vacuum degree of -83kPa) for 2min. When no obvious climbing phenomenon is observed in the reaction bottle, stop the vacuum operation, and after cooling and pelletizing, a polyamide elastomer can be obtained.

[0064] Examples 2 to 4 and Comparative Examples 1 to 2

[0065] Examples 2 to 4 and Comparative Examples 1 to 2 respectively provide a method for preparing a polyamide elastomer with high gas barrier properties and high resilience. Compared with Example 1, the only difference is that the amount of 2,5-furandicarboxylic acid added is changed. The amount of 2,5-furandicarboxylic acid added in each example and comparative example is shown in Table 1.

[0066] Table 1 Addition amount of 2,5-furandicarboxylic acid in Examples 1 to 4 and Comparative Examples 1 to 2

[0067] Example / Comparative Example Addition amount of 2,5-furandicarboxylic acid (g) Example 1 0.25 Example 2 0.5 Example 3 0.75 Example 4 1 Comparative Example 1 0.1 Comparative Example 2 1.5

[0068] Examples 5 to 8 and Comparative Examples 3 to 4

[0069] Examples 5 to 8 and comparative examples 3 to 4 respectively provide a method for preparing a polyamide elastomer with high gas barrier properties and high resilience. Compared with Example 1, the only difference is that the amount of polytetrahydrofuran added is changed. The amount of polytetrahydrofuran added in each example and comparative example is shown in Table 2.

[0070] Table 2 Addition amount of polytetrahydrofuran in Example 1, Examples 5 to 8 and Comparative Examples 3 to 4

[0071] Example / Comparative Example Addition amount of polytetrahydrofuran (g) Example 1 1 Example 5 1.5 Example 6 2 Example 7 2.5 Example 8 3 Comparative Example 3 0.5 Comparative Example 4 3.5

[0072] Examples 9 to 12 and Comparative Examples 5 to 6

[0073] Examples 9 to 11 and Comparative Examples 5 to 6 respectively provide a method for preparing a polyamide elastomer with high gas barrier properties and high resilience. Compared with Example 1, the only difference is that the amount of diphenylmethane diisocyanate added is changed. The amount of diphenylmethane diisocyanate added in each example and comparative example is shown in Table 3.

[0074] Table 3 Addition amount of diphenylmethane diisocyanate in Example 1, Examples 9 to 11 and Comparative Examples 5 to 6

[0075] Example / Comparative Example Addition amount of diphenylmethane diisocyanate (g) Example 1 1 Example 9 0.8 Example 10 0.9 Embodiment 11 1.2 Comparative Example 5 0.6 Comparative Example 6 1.3

[0076] 2. Test Method

[0077] 1. Test of gas barrier properties of polyamide elastomer

[0078] According to GB / T 1038.2-2022 "Test method for gas permeability of plastic film and sheet Part 2: Isobaric method", the isobaric method principle is used for testing. During the test, the pre-treated sample is clamped between the test chambers, oxygen flows on one side of the sample, and high-purity nitrogen flows on the other side of the film. Oxygen molecules diffuse through the film into the high-purity nitrogen on the other side, and are carried to the sensor by the flowing nitrogen for chemical reaction and generate voltage. According to Faraday's law, the voltage is proportional to the amount of oxygen passing through the sensor per unit time. By analyzing the oxygen concentration measured by the sensor, parameters such as oxygen permeability (OTR) can be calculated. The formula is as follows:

[0079]

[0080] Where: R OT is the oxygen transmission rate, cm 3 / (m 2 ·d·0.1MPa); k is the calibration constant of the instrument; U is the voltage of the sample, V; U 0 is the zero point voltage, V; A is the effective penetration area, m 2 ;p a is the ambient atmospheric pressure, Pa; p 0 is the oxygen partial pressure in the experimental gas, Pa.

[0081] 2. Test of breaking strength and breaking strain of polyamide elastomer

[0082] The tensile properties of polyamide elastomers were tested using an Instron 5967 universal tensile testing machine according to the GB / T 1040.2-2022 test standard to obtain their uniaxial tensile stress-strain curves, thereby obtaining their fracture strength and fracture strain. Test conditions: tensile test speed of 50 mm / min, 5 valid samples per group at 23°C. The area formed by the stress-strain curve and the horizontal and vertical axes is the fracture toughness of the material.

[0083] 3. Test on the resilience of polyamide elastomer

[0084] The sample was prepared by a universal testing machine (Instron 5967) according to the GB / T 1040.2-2022 test standard, and the elastic recovery curve of the polyamide elastomer was obtained by 5 cycles of stretching under constant elongation conditions (5%, 10%, 15%, 20%, 30%, etc.). In this application, the elastic recovery rate is determined by the elastic recovery curve measured at a constant elongation of 20%.

[0085] III. Analysis of test results of various embodiments and comparative examples

[0086] After the polyamide elastomers prepared in Examples 1 to 11 and Comparative Examples 1 to 6 were tested according to the above test method, the uniaxial tensile stress-strain curve and the one-cycle tensile resilience performance test curve of the polyamide elastomer prepared in Example 1 were respectively as follows: Figure 3 , Figure 4 The performance data test results of Examples 1 to 11 and Comparative Examples 1 to 6 are shown in Table 4.

[0087] Table 4 Performance data of polyamide elastomers prepared in Examples 1 to 11 and Comparative Examples 1 to 6

[0088]

[0089]

[0090] It can be seen from Table 4 that, with the amount of other raw materials remaining unchanged, as the amount of 2,5-furandicarboxylic acid added gradually increases, the gas barrier properties of the polyamide elastomer increase, and the oxygen permeability gradually decreases. Due to the increase in the content of urea bonds formed in the molecular chain, the strength of the polyamide elastomer gradually increases, the fracture strain gradually decreases, and the resilience also gradually decreases. When the amount of 2,5-furandicarboxylic acid added is too low, the hydrogen bonding effect between the molecular chains of the polyamide elastomer is significantly reduced, and its strength and gas barrier properties are significantly reduced. When the amount of 2,5-furandicarboxylic acid added is too high, the hydrogen bonding effect between the molecular chains is significantly enhanced, and the strength and gas barrier properties of the elastomer are significantly improved, but its resilience is too low to meet the application requirements.

[0091] With the amount of other raw materials remaining unchanged, as the amount of polytetrahydrofuran added gradually increases, the resilience and fracture strain of the polyamide elastomer increase due to the increase in the soft segment content in the molecular chain. However, due to the increase in the soft segment content in the molecular chain and the relatively reduced urea bond content, the gas barrier property of the polyamide elastomer decreases, the oxygen permeability gradually increases, and the strength of the elastomer gradually decreases. When the amount of polytetrahydrofuran added is too little, although the fracture strength of the polyamide elastomer increases, its resilience is too poor, the fracture strain decreases, and it cannot meet the application requirements. When the amount of polytetrahydrofuran added is too high, due to the excessively high soft segment content, the fracture strain of the polyamide elastomer increases sharply, the resilience performance is poor, and the gas barrier property and fracture strength also decrease sharply, which cannot meet the application requirements.

[0092] With the amount of other raw materials unchanged, as the amount of diphenylmethane diisocyanate added gradually increases, the hard segment content in the polyamide elastomer increases, the hydrogen bond interaction between the molecular chains is enhanced, the gas barrier property of the polyamide elastomer increases, the oxygen permeability decreases, the strength gradually increases, and the fracture strain and resilience decrease. When the amount of diphenylmethane diisocyanate added is too little, the hard segment content in the polyamide elastomer is too little, the hydrogen bond interaction between the molecular chains is weakened, the gas barrier property and strength of the polyamide elastomer are too low, the hard segment content is too low, and its resilience also decreases, which cannot meet the application requirements. When the amount of diphenylmethane diisocyanate added is too high, the hard segment content in the polyamide elastomer is too much, the hydrogen bond interaction between the molecular chains is too strong, and although the gas barrier property and strength of the polyamide elastomer increase, its fracture strain and resilience decrease significantly, which cannot meet the application requirements.

[0093] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for preparing a polyamide elastomer with high gas barrier properties and high resilience, characterized in that: The steps include: S1. Mixing a cyclic lactam with water, heating and performing a ring-opening reaction; then adding a predetermined amount of a diamine and furan dicarboxylic acid, performing a prepolymerization reaction, and obtaining a prepolymer; the mass ratio of the cyclic lactam, the diamine and the furan dicarboxylic acid is 50:0.8~1.2:0.25~1; S2. The prepolymer is mixed with diisocyanate and polyether diol to carry out a chain extension reaction to obtain a polyamide elastomer; the mass ratio of the prepolymer, the diisocyanate and the polyether diol is 50:0.8~1.2:1~3.

2. The method for preparing a polyamide elastomer having high gas barrier properties and high resilience according to claim 1, characterized in that: In step S1, the mass volume ratio of the cyclic lactam to water is 40-60 g:1 mL, and the temperature of the ring-opening reaction is 240-260°C.

3. The method for preparing a polyamide elastomer having high gas barrier properties and high resilience according to claim 1, characterized in that: In step S1, the prepolymerization temperature is 240-260°C, and the reaction time is 30-40 minutes.

4. The method for preparing a polyamide elastomer having high gas barrier properties and high resilience according to claim 1, characterized in that: In step S2, the temperature of the chain extension reaction is 240-260°C, and the reaction time is 30-40 minutes.

5. The method for preparing a polyamide elastomer having high gas barrier properties and high resilience according to claim 1, characterized in that: In step S2, the number average molecular weight of the polyether diol is 1000 to 5000 g / mol.

6. The method for preparing a polyamide elastomer having high gas barrier properties and high resilience according to claim 1, characterized in that: In step S2, the diisocyanate is at least one of diphenylmethane diisocyanate, toluene diisocyanate, and isophorone diisocyanate; and the polyether diol is at least one of polytetrahydrofuran, polyethylene glycol, and polypropylene glycol.

7. A polyamide elastomer having high gas barrier properties and high resilience, characterized in that: The preparation method according to any one of claims 1 to 6 is used to prepare the polyol, and the polyol comprises a hard segment and a soft segment.

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