Process for the preparation of an ultrahigh molecular weight long carbon chain nylon 1212 resin and the product thereof

Abstract

The application provides a preparation method of an ultrahigh molecular weight long carbon chain nylon 1212 resin and a product thereof. The preparation method is characterized in that the nylon 1212 crude salt is purified by using a polar solvent, the purity of the prepared refined nylon 1212 salt reaches a polymerization level, and the ultrahigh molecular weight nylon 1212 is prepared for the first time by using a melt polycondensation method. The preparation method has simple process, easy operation steps, no pollution and wide application prospect. The test shows that the tensile strength of the long carbon chain nylon 1212 resin prepared by using the preparation method is 52-55 MPa, the number average molecular weight can reach 38.5-42.5 kg / mol, and the molecular weight distribution is narrow, being 2.63-2.93. The above results show that the ultrahigh molecular weight nylon 1212 resin can be prepared by using the application, and the obtained nylon 1212 resin has excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of nylon preparation technology, specifically relating to a method for preparing ultra-high molecular weight long carbon chain nylon 1212 resin and its product. Background Technology

[0002] Nylon 1212, also known as polydodecanoic acid dodecanoic acid diamine, has a main chain structure composed of repeating units consisting of amide bonds formed by 12 methylene diacids and 12 methylene diamines. Its properties are comparable to Nylon 12 and Nylon 11, and it can replace long-chain nylons such as Nylon 12 and Nylon 11 in product applications. Studies have shown that Nylon 1212 possesses the unique characteristics of long-chain nylons, including low water absorption, good low-temperature resistance, dimensional stability, high strength, good toughness, and wear and shock absorption. It can be widely used in automotive, communications, machinery, electronics, textiles, aerospace, military, and sporting goods industries.

[0003] Nylon 1212 was first successfully developed by DuPont in 1988, using butadiene as a starting material. Patent 99108152.8 describes a method using petroleum-derived dodecanoic acid as a starting material, followed by nitrification and amination to obtain dodecanoic diamine, which is then neutralized with the petroleum-derived dodecanoic acid to prepare nylon salt. Finally, nylon 1212 is produced through polycondensation. However, this method has a long process route and is difficult to industrialize. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for preparing ultra-high molecular weight long carbon chain nylon 1212 resin and the product thereof. This preparation method is simple, easy to operate, and pollution-free.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] This invention provides a method for preparing ultra-high molecular weight long carbon chain nylon 1212 resin, comprising the following steps:

[0007] S1: Purify crude nylon 1212 salt in a polar solvent to obtain refined nylon 1212 salt;

[0008] The polar solvent is selected from any one or more of ethanol, methanol, or isopropanol;

[0009] S2: Refined nylon 1212 salt, catalyst and molecular weight regulator are subjected to polymerization reaction to obtain ultra-high molecular weight long carbon chain nylon 1212 resin.

[0010] Preferably, the purification process involves mixing crude nylon 1212 salt with a polar solvent, stirring at 50-70°C for 3-5 hours, and then allowing it to stand at room temperature for 1-3 hours.

[0011] Preferably, the purification process is performed 1 to 3 times.

[0012] Preferably, the purification process further includes filtration and drying steps.

[0013] Preferably, the drying temperature is 40~60℃ and the time is 24~48 h.

[0014] Preferably, the catalyst is selected from any one or more of phosphoric acid, phosphorous acid, sodium phosphite, sodium hypophosphite, or pyrophosphite.

[0015] Preferably, the molecular weight regulator is selected from dicarboxylic acids and / or diamines.

[0016] Preferably, the dicarboxylic acid is selected from any one or more of 1,4-succinic acid, 1,6-adipic acid, 1,7-heptanedic acid, 1,8-octanoic acid, 1,9-azelaic acid, 1,10-sebacic acid, 1,11-undecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,15-pentadecanedioic acid, or 1,16-hexadecanedicarboxylic acid.

[0017] Preferably, the diamine is selected from any one or more of 1,10-decanediamine, 1,11-undecanediamine, or 1,16-diaminohexadecane.

[0018] Preferably, the raw materials for the polymerization reaction also include an antioxidant.

[0019] Preferably, the antioxidant is selected from any one or more of IRGANOX1010, IRGANOX1076, IRGANOX1035, IRGANOX245, IRGANOX1098, IRGANOX1135 or IRGANOX1520.

[0020] Preferably, the mass ratio of the refined nylon 1212 salt, catalyst, optional antioxidant and molecular weight regulator is (389.1~809.4):(0.35~1.75):(0~1.88):(1.31~3.1).

[0021] More preferably, the mass ratio of the refined nylon 1212 salt, catalyst, optional antioxidant and molecular weight regulator is (389.1~809.4):(0.35~1.75):(0.79~1.88):(1.31~3.1).

[0022] Preferably, the polymerization reaction is carried out in an inert atmosphere.

[0023] Preferably, the inert atmosphere is one of nitrogen, carbon dioxide or argon.

[0024] Preferably, the polymerization reaction is as follows:

[0025] The reaction was carried out at 185–210 °C and 0.03–0.8 MPa for 0.5–1.5 h.

[0026] Heat to 230~250℃ and continue the reaction at 1.3~1.8 MPa for 35~50 min;

[0027] Continue heating to 270~290℃ and reacting under a vacuum of 50~150 Pa for 20~50 min.

[0028] Preferably, the crude nylon 1212 salt is obtained by reacting dodecanoic acid and dodecanoic diamine at 60-70°C.

[0029] The present invention also provides an ultra-high molecular weight long carbon chain nylon 1212 resin prepared by the above preparation method, the number average molecular weight of which is above 38 kg / mol.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This invention provides a method for preparing ultra-high molecular weight long-chain nylon 1212 resin. The method purifies crude nylon 1212 salt with a polar solvent, so that the purity of the prepared refined nylon 1212 salt reaches the polymerization grade. The method uses melt polycondensation to achieve the preparation of ultra-high molecular weight nylon 1212 for the first time. The preparation method is simple, easy to operate, pollution-free, and has broad application prospects.

[0032] Testing revealed that the long-chain nylon 1212 resin prepared using the above method exhibited a tensile strength of 52–55 MPa, a number-average molecular weight of 38.5–42.5 kg / mol, and a narrow molecular weight distribution of 2.63–2.93. These results demonstrate that the present invention yields high-purity nylon 1212 monomer salts, enabling the preparation of ultra-high molecular weight nylon 1212 resins, which possess excellent mechanical properties. Attached Figure Description

[0033] Figure 1 This is a GPC result diagram of the ultra-high molecular weight nylon 1212 resin prepared in Example 1;

[0034] Figure 2 The XRD pattern of the ultra-high molecular weight nylon 1212 resin prepared in Example 1;

[0035] Figure 3 The DSC image of the ultra-high molecular weight nylon 1212 resin prepared in Example 1;

[0036] Figure 4 The image shows the GPC results of the DSC diagram of the nylon 1212 resin prepared for Comparative Example 1. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] To address the problems of long process routes, difficulty in industrialization, and low molecular weight of nylon 1212 obtained by existing technologies, this invention provides a method for preparing ultra-high molecular weight long carbon chain nylon 1212 resin, comprising the following steps:

[0039] S1: Purify crude nylon 1212 salt in a polar solvent;

[0040] The polar solvent is selected from any one or more of ethanol, methanol, or isopropanol;

[0041] S2: Refined nylon 1212 salt, catalyst and molecular weight regulator are subjected to polymerization reaction to obtain ultra-high molecular weight long carbon chain nylon 1212 resin.

[0042] In this invention, the crude nylon 1212 salt is prepared by reacting dodecanoic acid and dodecanoic diamine, preferably in the presence of a solvent such as water. Since dodecanoic acid and dodecanoic diamine have low solubility in water, leading to incomplete reactions, this invention increases the reaction temperature to 60-70°C to improve the degree of reaction.

[0043] It should be noted that dodecanoic acid and dodecanoic diamine are long-chain compounds with low solubility in water. To improve the reaction rate, this invention increases the reaction temperature. Furthermore, if dodecanoic acid and dodecanoic diamine are added all at once during the reaction, a large amount of them can easily remain suspended in the system and aggregate. This can cause unreacted dodecanoic acid and dodecanoic diamine to be encapsulated by the generated salt, preventing further salt formation and leading to incomplete reaction. Therefore, this invention uses a batch-feeding method for dodecanoic acid to reduce the raw material concentration, increasing the contact probability between dodecanoic acid and dodecanoic diamine, thereby avoiding the encapsulation of unreacted raw materials by the generated salt and improving the reaction yield.

[0044] Exemplarily, in some embodiments of the present invention, the temperature of the reaction vessel is controlled at 60-70°C. Deionized water is added to the reaction vessel, and dodecanoic acid is added all at once. After stirring for 30-45 minutes, preferably 40-42 minutes, dodecanoic diamine is added to the reaction vessel in batches, preferably 3-5 times. After all the dodecanoic acid has been added, stirring continues for 1-4 hours, preferably 2-3 hours, until the pH of the reaction solution reaches 7-8. At this point, the reaction is stopped, ensuring that the dodecanoic acid and dodecanoic diamine react completely. The liquid in the reaction vessel is then filtered, and the filtrate is collected to obtain crude nylon 1212 salt. Generally, it is preferable to control the amount of dodecanoic diamine added in batches to gradually increase.

[0045] Although the present invention has increased the reaction degree between dodecanoic acid and dodecanoic diamine by increasing the reaction temperature and batch feeding in the above-mentioned process of preparing nylon 1212 crude salt, it is still inevitable that some raw materials will not react completely. Therefore, the present invention purifies the nylon 1212 crude salt in a polar solvent and extracts the unreacted raw materials, thereby improving the purity of the resulting refined nylon 1212 salt and avoiding the residue of small molecules such as dodecanoic acid or dodecanoic diamine, which would cause chain transfer in the nylon 1212 salt and result in a lower molecular weight of nylon 1212. The polar solvent is selected from any one or more of ethanol, methanol, or isopropanol, preferably ethanol, and more preferably anhydrous ethanol.

[0046] In this invention, the purification process involves mixing crude nylon 1212 salt with a polar solvent, stirring at 50-70°C for 3-5 hours, and then allowing it to stand at room temperature for 1-3 hours. The purification process is repeated 1-3 times, thereby maximizing the purity of the refined nylon 1212 salt through multiple purification and extraction processes with a polar solvent.

[0047] In this invention, the purification process preferably includes filtration and drying steps. The drying can be carried out using techniques well known to those skilled in the art, preferably vacuum drying, at a temperature of 40~60℃, more preferably 45~55℃, for a time of 24~48 h, more preferably 30~36 h.

[0048] Exemplary, in some embodiments of the present invention, crude nylon 1212 salt is preferably added to a purification vessel, anhydrous ethanol is added, and the temperature of the purification vessel is controlled at 50~70°C, preferably 55~60°C; stirring is performed for 3~5 h, preferably 3.5~4 h; then the mixture is allowed to stand at room temperature for 1~3 h, preferably 2 h, filtered, and the filtrate is collected. This process is repeated twice, and the obtained filtrate is vacuum dried at 40~60°C for 24~48 h to obtain refined nylon 1212 salt.

[0049] After obtaining refined nylon 1212 salt, according to the present invention, the refined nylon 1212 salt, catalyst and molecular weight regulator are subjected to polymerization reaction to obtain ultra-high molecular weight long carbon chain nylon 1212 resin.

[0050] In this invention, the catalyst is selected from any one or more of phosphoric acid, phosphorous acid, sodium phosphite, sodium hypophosphite, or pyrophosphite.

[0051] In this invention, the molecular weight regulator is selected from dicarboxylic acids and / or diamines; the dicarboxylic acid is selected from any one or more of 1,4-succinic acid, 1,6-adipic acid, 1,7-heptanedic acid, 1,8-octanoic acid, 1,9-azelanoic acid, 1,10-sebacic acid, 1,11-undecanediic acid, 1,13-tridecanediic acid, 1,14-tetradecanediic acid, 1,15-pentadecanedioic acid, or 1,16-hexadecanediic acid; the diamine is selected from any one or more of 1,10-decanediamine, 1,11-undecanediamine, or 1,16-diaminohexadecane.

[0052] It should be noted that in this invention, antioxidants can also be added to the raw materials of the polymerization reaction as needed, wherein the antioxidants are selected from any one or more of IRGANOX1010, IRGANOX1076, IRGANOX1035, IRGANOX245, IRGANOX1098, IRGANOX1135 or IRGANOX1520.

[0053] The present invention does not impose any particular restrictions on the source of the above-mentioned catalyst, antioxidant and molecular weight regulator, which can be commercially available products.

[0054] In some embodiments of the present invention, the mass ratio of the refined nylon 1212 salt, catalyst, antioxidant and molecular weight regulator is (389.1~809.4):(0.35~1.75):(0~1.88):(1.31~3.1), preferably (389.1~809.4):(0.35~1.75):(0.79~1.88):(1.31~3.1).

[0055] In this invention, the polymerization reaction is preferably carried out in an inert atmosphere, which is one of nitrogen, carbon dioxide or argon.

[0056] In this invention, the polymerization reaction procedure is set as follows:

[0057] The reaction was carried out at 185–210 °C and 0.03–0.8 MPa for 0.5–1.5 h.

[0058] Heat to 230~250℃ and continue the reaction at 1.3~1.8 MPa for 35~50 min;

[0059] Continue heating to 270~290℃ and reacting under a vacuum of 50~150 Pa for 20~50 min.

[0060] Preferably, in this invention, the polymerization reaction procedure is set as follows:

[0061] The reaction was carried out at 190–205 °C and 0.05–0.6 MPa for 0.8–1.2 h.

[0062] Heat to 235~240℃ and continue the reaction at 1.3~1.5 MPa for 40~45 min;

[0063] Continue heating to 275~280℃ and reacting under a vacuum of 70~120 Pa for 25~40 min.

[0064] In this invention, the polymerization reaction is carried out according to the above procedure because the nylon reaction is a step-growth polymerization reaction. If the initial temperature is too high, small molecule prepolymers (molecular weight less than 1000) will be distributed in various parts of the reactor, including the reactor walls and valves, making it difficult to ensure that the molecular weight of the prepolymer continues to increase. Moreover, in industrial preparation, small molecule prepolymers will clog the pipes. Therefore, this invention adopts a step-growth heating procedure and uses negative pressure in the final step to remove free small molecule prepolymers (molecular weight less than 500) from the reaction system. This is a "concentration" process for nylon 1212 resin, which is beneficial for obtaining ultra-high molecular weight nylon.

[0065] Exemplary, in some embodiments of the present invention, refined nylon 1212 salt, catalyst, antioxidant, and molecular weight regulator are preferably added to the polymerization reactor. The air in the reactor is replaced with an inert protective gas, and the pressure inside the reactor is controlled at 0.03~0.8 MPa. The reactor temperature is controlled at 185~210℃, and the reaction is carried out for 0.5~1.5 h. The reactor temperature is then raised to 230~250℃, and the polymerization reactor pressure reaches 1.3~1.8 MPa. The reaction continues for 35~50 min. The temperature is then raised further to 270~290℃, the gas is released to atmospheric pressure, and then negative pressure is applied, with a vacuum of 50~150 Pa for 20~50 min.

[0066] Finally, considering the practical applications of nylon 1212 resin, this invention discharges the material in the polymerization reactor through the spinneret under inert gas protection, and then performs underwater stripping and pelletizing to obtain nylon 1212 resin.

[0067] Testing revealed that the long-chain nylon 1212 resin prepared using the above method exhibited a tensile strength of 52–55 MPa, a number-average molecular weight of 38.5–42.5 kg / mol, and a narrow molecular weight distribution of 2.63–2.93. These results demonstrate that the present invention yields high-purity nylon 1212 monomer salts, enabling the preparation of ultra-high molecular weight nylon 1212 resins, which possess excellent mechanical properties.

[0068] To further illustrate the present invention, the following embodiments provide a detailed description. The experimental materials used in the following embodiments of the present invention are all commercially available products.

[0069] Example 1

[0070] This embodiment provides an ultra-high molecular weight nylon 1212 resin, the preparation method of which is as follows:

[0071] (1) Control the temperature of the reactor at 60℃, add 1500 g of deionized water to the reactor, add 342.5 g (1.5 mol) of dodecanedicarboxylic acid at once, stir for 30 min, add 340.6 g (1.7 mol) of dodecanediamine in 3 portions (80 g, 120 g and 140.6 g each time), after all the dodecanediamine is added, continue stirring for 1 h, stop the reaction when the pH of the reaction solution reaches 8, filter the liquid in the reactor, collect the filtrate, and obtain crude nylon 1212 salt.

[0072] (2) Add the crude nylon 1212 salt obtained in step (1) into the purification kettle, add 1200 g of anhydrous ethanol, control the temperature of the purification kettle at 50℃, stir for 5 h, let stand at room temperature for 2 h, filter, collect the filtrate, repeat the process twice, dry the filtrate under vacuum at 40℃ for 48 h to obtain refined nylon 1212 salt;

[0073] (3) Add the refined nylon 1212 salt obtained in step (2), 0.38 g of phosphoric acid, 0.95 g of IRGANOX 1010 and 1.52 g of 1,6-adipic acid to the polymerization reactor. Replace the air in the reactor with nitrogen and control the pressure inside the reactor at 0.03 MPa. Heat the reactor to control the temperature at 185℃ and react for 1.5 h. Raise the temperature of the reactor to 230℃ and the pressure of the polymerization reactor to 1.3 MPa. Continue the reaction for 50 min. Continue to raise the temperature to 270℃, release the gas to atmospheric pressure, and then start negative pressure and evacuate. The vacuum degree reaches 5 Pa and the negative pressure time is 20 min.

[0074] (4) Under nitrogen protection, the material in the polymerization reactor is discharged through the spinneret hole, and then pulled and granulated underwater to obtain ultra-high molecular weight nylon 1212 resin.

[0075] The GPC results of the ultra-high molecular weight nylon 1212 resin provided in this embodiment are shown in the figure below. Figure 1 As shown in Table 1, the molecular weight statistics are as follows: the number-average molecular weight is 41.2 kg / mol, and the molecular weight distribution index is 2.87.

[0076] The XRD and DSC images of the ultra-high molecular weight nylon 1212 resin provided in this embodiment are as follows: Figure 2 and Figure 3 As shown, by Figure 2 It can be seen that the obtained nylon 1212 exhibits characteristic nylon peaks at 6.15°, 21.21°, and 39.45°, with two sharp peaks at 6.15° and 21.21°, indicating that the nylon of this invention possesses excellent crystallinity. Figure 3 The melting point is 186.5℃.

[0077] Example 2

[0078] This embodiment provides an ultra-high molecular weight nylon 1212, the preparation method of which is as follows:

[0079] (1) The temperature of the reactor was controlled at 70℃. 1300 g of deionized water was added to the reactor. 296.8 g (1.3 mol) of dodecanedicarboxylic acid was added at once and stirred for 45 min. 221.6 g (1.1 mol) of dodecanediamine was added to the reactor in 3 portions (50 g, 70 g and 101.6 g each time). After all the contents were added, stirring was continued for 4 h. The reaction was stopped when the pH of the reaction solution reached 6. The liquid in the reactor was filtered and the filtrate was collected to obtain crude nylon 1212 salt.

[0080] (2) Add the crude nylon 1212 salt prepared in (1) to the purification vessel, add 1150 g of anhydrous ethanol, control the temperature of the purification vessel at 70℃, stir for 3 h, let stand at room temperature for 2 h, filter, collect the filtrate, repeat the process twice, dry the obtained filtrate under vacuum at 60℃ for 24 h to obtain refined nylon 1212 salt;

[0081] (3) Add refined nylon 1212 salt, 0.56 g phosphorous acid, 1.85 g IRGANOX 1076 and 2.5 g 1,10-sebacic acid to the polymerization reactor. Replace the air in the reactor with carbon dioxide gas and control the pressure inside the reactor at 0.8 MPa. Heat the reactor to control the temperature at 210℃ and react for 0.5 h. Raise the temperature of the reactor to 250℃ and the pressure of the polymerization reactor reaches 1.8 MPa. Continue the reaction for 35 min. Continue to raise the temperature to 290℃, release the gas to atmospheric pressure, and then start negative pressure and evacuate. The vacuum degree reaches 150 Pa and the negative pressure time is 50 min.

[0082] (4) Under nitrogen protection, the material in the polymerization reactor is discharged through the spinneret hole, and then pulled and granulated underwater to obtain ultra-high molecular weight nylon 1212 resin.

[0083] Example 3

[0084] This embodiment provides an ultra-high molecular weight nylon 1212, the preparation method of which is as follows:

[0085] (1) Control the temperature of the reactor at 65℃, add 800 g of deionized water to the reactor, add 228.5 g of dodecanedicarboxylic acid at once, stir for 40 min, add 219.5 g of dodecanediamine in 3 portions (50 g, 70 g and 99.5 g each time), continue stirring for 2 h after all the addition, stop the reaction when the pH of the reaction solution reaches 7.5, filter the liquid in the reactor, collect the filter material, and obtain crude nylon 1212 salt.

[0086] (2) Add the crude nylon 1212 salt prepared in step (1) to the purification kettle, add 680 g of anhydrous ethanol, control the temperature of the purification kettle at 60℃, stir for 3.5 h, place at room temperature for 2 h, filter, collect the filtrate, repeat the process twice, dry the obtained filtrate under vacuum at 50℃ for 36 h to obtain refined nylon 1212 salt;

[0087] (3) Add the refined nylon 1212 salt obtained in step (2), 1.25 g of sodium phosphite, 0.79 g of IRGANOX1035 and 3.1 g of 1,10-decanediamine to the polymerization reactor. Replace the air in the reactor with argon gas and control the pressure inside the reactor at 0.2 MPa. Heat the reactor to control the temperature at 190℃ and react for 1 h. Raise the temperature of the reactor to 240℃ and the pressure of the polymerization reactor to 1.5 MPa. Continue the reaction for 40 min. Continue to raise the temperature to 280℃, release the gas to atmospheric pressure, and then start negative pressure and evacuate. The vacuum degree reaches 100 Pa and the negative pressure time is 30 min.

[0088] (4) Under nitrogen protection, the material in the polymerization reactor is discharged through the spinneret hole, and then pulled and granulated underwater to obtain ultra-high molecular weight nylon 1212 resin.

[0089] Example 4

[0090] This embodiment provides an ultra-high molecular weight nylon 1212, the preparation method of which is as follows:

[0091] (1) Control the temperature of the reactor at 68℃, add deionized water to the reactor, add 182.6 g of dodecanedicarboxylic acid at once, stir for 35 min, add 206.5 g of dodecanediamine in 3 portions (40 g, 60 g and 106.5 g each time), and continue stirring for 3 h after all the addition. Stop the reaction when the pH of the reaction solution reaches 8, filter the liquid in the reactor, collect the filter material, and obtain crude nylon 1212 salt.

[0092] (2) Add the crude nylon 1212 salt obtained in step (1) into the purification vessel, add 510 g of anhydrous ethanol, control the temperature of the purification vessel at 55℃, stir for 4.5 h, place at room temperature for 2 h, filter, collect the filtrate, repeat the process twice, and vacuum dry the obtained filtrate at 55℃ for 24 h to obtain refined nylon 1212 salt.

[0093] (3) Add the refined nylon 1212 salt obtained in step (2), 1.35 g of sodium hypophosphite, 1.85 g of IRGANOX1098 and 1.31 g of 1,16-diaminohexadecane to the polymerization reactor. Replace the air in the reactor with nitrogen and control the pressure inside the reactor at 0.5 MPa. Heat the reactor to control the temperature at 200℃ and react for 1.5 h. Raise the temperature of the reactor to 235℃ and the pressure of the polymerization reactor to 1.4 MPa. Continue the reaction for 45 min. Continue to raise the temperature to 285℃, release the gas to atmospheric pressure, and then start negative pressure and evacuate. The vacuum degree reaches 50 Pa and the negative pressure time is 35 min.

[0094] (4) Under nitrogen protection, the material in the polymerization reactor is discharged through the spinneret hole, and then pulled and granulated underwater to obtain ultra-high molecular weight nylon 1212 resin.

[0095] Example 5

[0096] This embodiment provides an ultra-high molecular weight nylon 1212, the preparation method of which is as follows:

[0097] (1) Control the temperature of the reactor at 70℃, add 1100 g of deionized water to the reactor, add 274.5 g of dodecanedicarboxylic acid at once, stir for 40 min, add 210.4 g of dodecanediamine in 3 portions (30 g, 70 g and 110.4 g each time), and continue stirring for 2.5 h after all the addition. Stop the reaction when the pH of the reaction solution reaches 7.5, filter the liquid in the reactor, collect the filter material, and obtain crude nylon 1212 salt.

[0098] (2) Add the crude nylon 1212 salt obtained in step (1) into the purification vessel, add 500 g of anhydrous ethanol, control the temperature of the purification vessel at 55℃, stir for 3.5 h, place at room temperature for 2 h, filter, collect the filtrate, repeat the process twice, dry the filtrate under vacuum at 50℃ for 30 h to obtain refined nylon 1212 salt;

[0099] (3) Add the refined nylon 1212 salt, 0.35 g of phosphorous acid, 0.86 g of IRGANOX 1135 and 1.65 g of 1,16-diaminohexadecane from step (2) to the polymerization reactor. Replace the air in the reactor with nitrogen and control the pressure inside the reactor at 0.5 MPa. Heat the reactor to control the temperature at 198℃ and react for 1.5 h. Raise the temperature of the reactor to 245℃ and the pressure of the polymerization reactor to 1.7 MPa. Continue the reaction for 40 min. Continue to raise the temperature to 280℃, release the gas to atmospheric pressure, and then start negative pressure and evacuate. The vacuum degree reaches 100 Pa and the negative pressure time is 35 min.

[0100] (4) Under nitrogen protection, the material in the polymerization reactor is discharged through the spinneret hole, and then pulled and granulated underwater to obtain ultra-high molecular weight nylon 1212 resin.

[0101] Example 6

[0102] This embodiment provides an ultra-high molecular weight nylon 1212, the preparation method of which is as follows:

[0103] (1) Control the temperature of the reactor at 63℃, add deionized water into the reactor, add 410.9 g of dodecanedicarboxylic acid at once, stir for 35 min, add 398.5 g of dodecanediamine into the reactor in 3 portions (100 g, 130 g, and 168.5 g each time), and continue stirring for 3 h after all the addition. Stop the reaction when the pH of the reaction solution reaches 7.8, filter the liquid in the reactor, collect the filtrate, and obtain crude nylon 1212 salt.

[0104] (2) Add the crude nylon 1212 salt obtained in step (1) into the purification vessel, add 1400 g of anhydrous ethanol, control the temperature of the purification vessel at 60℃, stir for 4 h, place at room temperature for 2 h, filter, collect the filtrate, repeat the process twice, dry the filtrate under vacuum at 50℃ for 40 h to obtain refined nylon 1212 salt;

[0105] (3) Add the refined nylon 1212 salt, 1.75 g phosphorous acid, 1.88 g IRGANOX 1520 and 2.3 g 1,7-heptanediol from step (2) to the polymerization reactor. Replace the air in the reactor with carbon dioxide and control the pressure inside the reactor at 0.4 MPa. Heat the reactor to control the temperature at 200℃ and react for 1 h. Raise the temperature of the reactor to 235℃ and the pressure of the polymerization reactor to 1.4 MPa. Continue the reaction for 45 min. Continue to raise the temperature to 275℃, release the gas to atmospheric pressure, and then start negative pressure and evacuate. The vacuum degree reaches 80 Pa and the negative pressure time is 40 min.

[0106] (4) Under nitrogen protection, the material in the polymerization reactor is discharged through the spinneret hole, and then pulled and granulated underwater to obtain ultra-high molecular weight nylon 1212 resin.

[0107] Example 7

[0108] This embodiment provides a nylon 1212, the preparation method of which is as follows:

[0109] The preparation method is the same as in Example 1, except that anhydrous ethanol in step (1) is replaced with methanol, while other reaction conditions remain unchanged.

[0110] Example 8

[0111] This embodiment provides a nylon 1212, the preparation method of which is as follows:

[0112] Prepared according to the method of Example 1, except that anhydrous ethanol in step (1) is replaced with isopropanol, while other reaction conditions remain unchanged.

[0113] Comparative Example 1

[0114] This comparative example provides a nylon 1212, the preparation method of which is as follows:

[0115] The polymerization was carried out using the following polymerization method, according to the raw material ratio of Example 1.

[0116] (1) Add 342.5 g of dodecanoic acid, 340.6 g of dodecanoic diamine, 0.38 g of phosphoric acid, 0.95 g of IRGANOX1010 and 1.52 g of 1,6-adipic acid to the polymerization reactor. Replace the air in the reactor with nitrogen and control the pressure inside the reactor at 0.03 MPa. Heat the reactor to control the temperature at 185℃ and react for 1.5 h. Raise the temperature of the reactor to 230℃ and the pressure in the polymerization reactor reaches 1.3 MPa. Continue the reaction for 50 min.

[0117] (2) The polymerization reactor is heated to 270°C, the pressure is released to atmospheric pressure, and then negative pressure is started. The vacuum degree reaches 50 Pa and the negative pressure time is 20 min.

[0118] (3) Under nitrogen protection, the material in the polymerization reactor is discharged through the spinneret hole, and then pulled and granulated underwater to obtain nylon 1212 resin.

[0119] The GPC results of the nylon 1212 resin provided in this comparative example are shown in the figure below. Figure 4 As shown, the number-average molecular weight is 10.6 kg / mol, and the molecular weight distribution index is 5.70.

[0120] Comparative Example 2

[0121] This comparative example provides a nylon 1212, the preparation method of which is as follows:

[0122] (1) At room temperature, 342.5 g of dodecanoic acid was added to 200 g of anhydrous ethanol and heated to 60°C to form a dispersion. Then, 340.6 g of dodecanoic diamine was added to the polymerization reactor and stirred for 1.5 h to obtain a nylon 1212 salt solution. The solution was filtered, the filtrate was collected, and the filtrate was dried under vacuum at 45°C for 48 h to obtain nylon 1212 salt.

[0123] (2) The nylon 1212 salt obtained in (1), 750 g of deionized water, 0.38 g of phosphoric acid, 0.95 g of IRGANOX1010 and 1.52 g of 1,6-adipic acid were added to the polymerization reactor. The air inside the reactor was replaced with high-purity nitrogen. The temperature was raised to 195°C and the pressure inside the polymerization reactor reached 1.5 MPa. After holding the temperature for 1.5 h, the gas was slowly released to atmospheric pressure. Then, the temperature was raised to 250°C and a vacuum was drawn. The vacuum degree was drawn to 50 kPa.

[0124] (3) Under nitrogen protection, the material in the polymerization reactor is discharged through the spinneret hole, and then pulled and granulated underwater to obtain nylon 1212 resin.

[0125] Performance testing

[0126] (1) Mechanical properties

[0127] In an injection molding machine, the temperature was raised to 340°C, and the nylon 1212 resin obtained in the above examples and comparative examples was melted at an injection pressure of 600 kgf / cm². 2 Injection-molded samples were obtained under the conditions of injection time of 2.0 s and mold temperature of 200℃, and mechanical strength tests were conducted under absolutely dry conditions.

[0128] (2) Molecular weight and its distribution

[0129] 10 mg of the nylon 1212 resin samples obtained in the above examples and comparative examples were dissolved in 10 g of hexafluoroisopropanol to prepare nylon solutions, which were then subjected to GPC testing.

[0130] The performance test results of all samples obtained in Examples 1-8 and Comparative Examples 1-2 are shown in Table 1 below:

[0131] Table 1

[0132]

[0133] As shown in Table 1, the tensile strength of the nylon 1212 resin provided by this invention is 52-55 MPa, which is much higher than the tensile strength of 41-44 MPa of the comparative example. The number-average molecular weight of the nylon 1212 resin prepared by this invention can reach 38.5-42.5 g / mol, with a narrow molecular weight distribution of 2.63-2.93, while the comparative example has a lower molecular weight of 9.8-24.7 kg / mol and a wider molecular weight distribution of 4.41-5.81. This is because this invention obtains high-purity nylon 1212 monomer salt, which can be used to prepare ultra-high molecular weight nylon 1212 resin. In contrast, the purity of the nylon 1212 monomer salt in the comparative example is low, and the presence of more impurities makes it difficult to obtain high molecular weight nylon 1212 resin.

[0134] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing ultra-high molecular weight long-chain carbon nylon 1212 resin, characterized in that, Includes the following steps: S1: Purify crude nylon 1212 salt in a polar solvent to obtain refined nylon 1212 salt; The polar solvent is selected from any one or more of ethanol, methanol, or isopropanol; S2: Refined nylon 1212 salt, catalyst and molecular weight regulator are subjected to polymerization reaction to obtain ultra-high molecular weight long carbon chain nylon 1212 resin. The catalyst is selected from any one or more of phosphoric acid, phosphorous acid, sodium phosphite, sodium hypophosphite, or pyrophosphite. The molecular weight regulator is selected from dicarboxylic acids and / or diamines; The dicarboxylic acid is selected from any one or more of 1,4-succinic acid, 1,6-adipic acid, 1,7-heptanediic acid, 1,8-octanoic acid, 1,9-azelaic acid, 1,10-sebacic acid, 1,11-undecanediic acid, 1,13-tridecanediic acid, 1,14-tetradecanediic acid, 1,15-pentadecanedioic acid, or 1,16-hexadecanediic acid. The diamine is selected from any one or more of 1,10-decanediamine, 1,11-undecanediamine, or 1,16-diaminohexadecane.

2. The preparation method according to claim 1, characterized in that, The purification process involves mixing crude nylon 1212 salt with a polar solvent, stirring at 50-70°C for 3-5 hours, and then allowing it to stand at room temperature for 1-3 hours. The purification process is repeated 1 to 3 times.

3. The preparation method according to claim 1 or 2, characterized in that, The purification process also includes filtration and drying steps. The drying temperature is 40~60℃ and the time is 24~48 h.

4. The preparation method according to claim 1, characterized in that, The raw materials for the polymerization reaction also include antioxidants; The antioxidant is selected from any one or more of IRGANOX1010, IRGANOX1076, IRGANOX1035, IRGANOX245, IRGANOX1098, IRGANOX1135 or IRGANOX1520.

5. The preparation method according to claim 1, characterized in that, The mass ratio of the refined nylon 1212 salt, catalyst, optional antioxidant, and molecular weight regulator is (389.1~809.4):(0.35~1.75):(0~1.88):(1.31~3.1).

6. The preparation method according to claim 1, characterized in that, The polymerization reaction is carried out in an inert atmosphere; The inert atmosphere is one of nitrogen, carbon dioxide or argon.

7. The preparation method according to claim 1, characterized in that, The polymerization reaction is as follows: The reaction was carried out at 185–210 °C and 0.03–0.8 MPa for 0.5–1.5 h. Heat to 230~250℃ and continue the reaction at 1.3~1.8 MPa for 35~50 min; Continue heating to 270~290℃ and reacting under a vacuum of 50~150 Pa for 20~50 min.

8. The preparation method according to claim 1, characterized in that, The crude nylon 1212 salt is obtained by reacting dodecanoic acid and dodecanoic diamine at 60-70°C.

9. The ultra-high molecular weight long carbon chain nylon 1212 resin prepared by the preparation method according to claim 1, characterized in that, Its number-average molecular weight is above 38 kg / mol.

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