Preparation method of ultra-high molecular weight long carbon chain nylon 1212 resin and product thereof

Abstract

The invention provides a preparation method of ultra-high molecular weight long carbon chain nylon 1212 resin and a product of the ultra-high molecular weight long carbon chain nylon 1212 resin. According to the preparation method, the nylon 1212 crude salt is purified by adopting the polar solvent, so that the purity of the prepared refined nylon 1212 salt reaches a polymer grade, the preparation of the ultrahigh molecular weight nylon 1212 is realized for the first time by adopting a melt polycondensation method, and the preparation method is simple in process, easy to operate in steps, free of pollution and wide in application prospect. Tests show that the tensile strength of the long carbon chain nylon 1212 resin prepared by 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 and is 2.63-2.93. The results show that the ultrahigh molecular weight nylon 1212 resin can be prepared, and the obtained nylon 1212 resin has excellent mechanical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of nylon preparation, and specifically relates to a preparation method of ultra-high molecular weight long carbon chain nylon 1212 resin and a product thereof. Background Art

[0002] Nylon 1212, also known as polydodecane diamide, has a main chain structure with repeating units consisting of 12 methylene dicarboxylic acids and 12 methylene diamines forming an amide bond group. Its performance is equivalent to that of nylon 12 and nylon 11, and it can replace long carbon chain nylons such as nylon 12 and nylon 11 during product use. According to research, nylon 1212 has the unique characteristics of long carbon chain nylon, such as low water absorption, good low temperature resistance, dimensional stability, high strength, good toughness, and wear resistance and shock absorption. It can be widely used in the fields of automobiles, communications, machinery, electronic appliances, textiles, aerospace, military, and sports goods.

[0003] Nylon 1212 was first successfully developed by Dupont in the United States in 1988, using butadiene as the starting material to prepare nylon 1212. Invention patent 99108152.8 uses petroleum fermented dodecanedioic acid as the starting material, obtains dodecanedioamine through nitrilation and amination, and then neutralizes with petroleum fermented dodecanedioic acid to prepare nylon salt, and finally prepares nylon 1212 through polycondensation, but this method has a long process route and is difficult to industrialize. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a preparation method of ultra-high molecular weight long carbon chain nylon 1212 resin and its product. The preparation method has simple process, easy operation steps and no pollution.

[0005] To achieve this object, the present invention adopts the following technical solutions:

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

[0007] S1: purifying nylon 1212 crude 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: subjecting the refined nylon 1212 salt, the catalyst and the molecular weight regulator to polymerization reaction to obtain an ultra-high molecular weight long carbon chain nylon 1212 resin.

[0010] Preferably, the purification is as follows: after mixing nylon 1212 crude salt with a polar solvent, stirring at 50-70° C. for 3-5 hours, and standing at room temperature for 1-3 hours.

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

[0012] Preferably, after the purification is completed, filtering and drying steps are also included.

[0013] Preferably, the drying temperature is 40-60° C. and the drying 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 pyrophosphorous acid.

[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-butanediol, 1,6-hexanediol, 1,7-heptanedioic acid, 1,8-octanedioic acid, 1,9-nonanediol, 1,10-decanedioic acid, 1,11-undecanedioic acid, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanedioic acid or 1,16-hexadecanedioic 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, the catalyst, the optional antioxidant and the 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, the catalyst, the optional antioxidant and the 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:

[0025] At 185~210℃, 0.03~0.8 MPa, react for 0.5~1.5 h;

[0026] Raise the temperature to 230-250°C and continue the reaction at 1.3-1.8 MPa for 35-50 min;

[0027] Continue to raise the temperature to 270~290℃ and react for 20~50 min under a vacuum degree of 50~150 Pa.

[0028] Preferably, the nylon 1212 crude salt is obtained by reacting dodecanedioic acid and dodecanediamine 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, wherein the number average molecular weight is above 38 kg / mol.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The invention provides a method for preparing an ultra-high molecular weight long carbon chain nylon 1212 resin. The method adopts a polar solvent to purify nylon 1212 crude salt so that the purity of the prepared refined nylon 1212 salt reaches the polymerization grade, and adopts a melt polycondensation method to realize the preparation of ultra-high molecular weight nylon 1212 for the first time. The preparation method has simple process, easy steps to operate, no pollution, and broad application prospects.

[0032] After testing, the tensile strength of the long carbon chain nylon 1212 resin prepared by the above 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 relatively narrow, 2.63-2.93. The above results show that the present invention obtains a high-purity nylon 1212 monomer salt, can prepare an ultra-high molecular weight nylon 1212 resin, and the obtained nylon 1212 resin has excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0036] Figure 4 This is the GPC result diagram of the DSC diagram of nylon 1212 resin prepared in Comparative Example 1. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In view of the problems that the prior art for preparing nylon 1212 has a long process route, is difficult to industrialize, and has a low molecular weight of the obtained nylon 1212, the present invention provides a method for preparing an ultra-high molecular weight long carbon chain nylon 1212 resin, comprising the following steps:

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

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

[0041] S2: subjecting the refined nylon 1212 salt, the catalyst and the molecular weight regulator to polymerization reaction to obtain an ultra-high molecular weight long carbon chain nylon 1212 resin.

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

[0043] It should be noted that dodecanedioic acid and dodecanedioamine belong to long carbon chain compounds, and their solubility in water is low. In order to improve the degree of reaction, the present invention increases the reaction temperature. In addition, during the reaction, if dodecanedioic acid and dodecanedioamine are fed once, it is easy to cause a large amount of dodecanedioic acid and dodecanedioamine to be suspended in the system, and gather together, so that unreacted dodecanedioic acid and dodecanedioamine raw materials can be wrapped by the generated salt, thereby preventing further salt-forming reaction, resulting in incomplete reaction. Therefore, the present invention adopts the mode of feeding dodecanedioic acid in batches, reduces the raw material concentration, increases the contact probability of dodecanedioic acid and dodecanedioamine, thereby avoiding the situation that unreacted raw materials are wrapped by the generated salt, and improves the reaction yield.

[0044] Exemplarily, in some embodiments of the present invention, the temperature of the reactor is controlled at 60-70°C, deionized water is added to the reactor, dodecanedioic acid is added at one time, stirred for 30-45 min, preferably 40-42 min, and dodecanedioamine is added to the reactor in batches, preferably 3-5 times, and after all are added, stirring is continued for 1-4 h, preferably 2-3 h, until the pH value of the reaction solution reaches 7-8, the reaction is stopped, and the dodecanedioic acid and dodecanedioamine react completely at this time, and the liquid in the reactor is filtered, and the filtrate is collected to obtain nylon 1212 crude salt. Generally, it is preferred to control the amount of dodecanedioamine added in batches to gradually increase.

[0045] Although, in the process of preparing nylon 1212 crude salt, the reaction degree of dodecane dicarboxylic acid and dodecane diamine has been increased by increasing the reaction temperature and feeding in batches, it is still inevitable that the raw materials are not completely reacted. Therefore, the present invention purifies the nylon 1212 crude salt in a polar solvent, extracts the unreacted raw materials, thereby improving the purity of the generated refined nylon 1212 salt, avoiding the residue of small molecules such as dodecane dicarboxylic acid or dodecane diamine, causing chain transfer of nylon 1212 salt, resulting in a lower molecular weight of nylon 1212. Wherein, the polar solvent is selected from any one or more of ethanol, methanol or isopropanol, preferably ethanol, and more preferably anhydrous ethanol.

[0046] In the present invention, the purification is as follows: after mixing nylon 1212 crude salt with a polar solvent, stirring at 50-70°C for 3-5 hours, and standing at room temperature for 1-3 hours. The purification is performed 1-3 times, so that the purity of the refined nylon 1212 salt can be improved as much as possible through multiple purification and extraction processes of polar solvents.

[0047] In the present invention, after the purification is completed, it is preferred that the steps of filtering and drying are further included. The drying can be carried out according to the technical means well known to those skilled in the art, preferably vacuum drying, the drying temperature is 40-60°C, preferably 45-55°C, and the drying time is 24-48 hours, preferably 30-36 hours.

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

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

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

[0051] In the present 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-butanediol, 1,6-hexanediol, 1,7-heptanedioic acid, 1,8-octanedioic acid, 1,9-nonanedioic acid, 1,10-decanedioic acid, 1,11-undecanedioic acid, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanedioic acid or 1,16-hexadecanediol; the diamine is selected from any one or more of 1,10-decanediamine, 1,11-undecanedioic acid or 1,16-diaminohexadecane.

[0052] It should be noted that in the present invention, an antioxidant may be added to the raw materials of the polymerization reaction as needed, wherein the antioxidant is selected from any one or more of IRGANOX1010, IRGANOX1076, IRGANOX1035, IRGANOX245, IRGANOX1098, IRGANOX1135 or IRGANOX1520.

[0053] The present invention has no particular limitation on the sources of the catalyst, antioxidant and molecular weight regulator, and they may be generally 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 the present invention, the polymerization reaction is preferably carried out in an inert atmosphere, which is one of nitrogen, carbon dioxide or argon.

[0056] In the present invention, the polymerization reaction is performed as follows:

[0057] At 185~210℃, 0.03~0.8 MPa, react for 0.5~1.5 h;

[0058] Raise the temperature to 230-250°C and continue the reaction at 1.3-1.8 MPa for 35-50 min;

[0059] Continue to raise the temperature to 270~290℃ and react for 20~50 min under a vacuum degree of 50~150 Pa.

[0060] Preferably, in the present invention, the polymerization reaction is performed as follows:

[0061] At 190~205℃, 0.05~0.6 MPa, the reaction time is 0.8~1.2 h;

[0062] Raise the temperature to 235-240°C and continue the reaction at 1.3-1.5 MPa for 40-45 min;

[0063] Continue to raise the temperature to 275~280℃ and react for 25~40 min under a vacuum degree of 70~120 Pa.

[0064] In the present invention, the polymerization reaction is carried out according to the above procedure because the nylon reaction is a step-by-step polymerization reaction. If the initial temperature is too high, small molecule prepolymers (molecular weight within 1000) will be distributed in various parts of the reactor, including the reactor wall, valves, etc., making it difficult to ensure that the molecular weight of the prepolymer continues to grow. In addition, during industrial preparation, small molecule prepolymers will block the pipeline. Therefore, the present invention adopts a step-by-step temperature increase procedure and uses negative pressure in the last step to remove the free small molecule prepolymers (molecular weight less than 500) in the reaction system. This is a "concentration" process for nylon 1212 resin, which is conducive to obtaining ultra-high molecular weight nylon.

[0065] Exemplarily, in some embodiments of the present invention, it is preferred to add refined nylon 1212 salt, catalyst, antioxidant and molecular weight regulator to the polymerization reactor, replace the air in the reactor with an inert protective gas, control the pressure in the reactor to 0.03~0.8 MPa, heat and control the reactor temperature to 185~210°C, and react for 0.5~1.5 h. The reactor is heated to 230~250°C, the polymerization reactor pressure reaches 1.3~1.8 MPa, and the reaction is continued for 35~50 min; the temperature is continued to rise to 270~290°C, the air is vented to normal pressure, and then negative pressure is started, vacuum is drawn, the vacuum degree reaches 50~150 Pa, and the negative pressure time is 20~50min.

[0066] Finally, considering the practical application of nylon 1212 resin, the present invention discharges the material in the polymerization kettle through the spinneret under the protection of inert gas, draws the strips underwater, and cuts the pellets to obtain nylon 1212 resin.

[0067] After testing, the tensile strength of the long carbon chain nylon 1212 resin prepared by the above 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 relatively narrow, 2.63-2.93. The above results show that the present invention obtains a high-purity nylon 1212 monomer salt, can prepare an ultra-high molecular weight nylon 1212 resin, and the obtained nylon 1212 resin has excellent mechanical properties.

[0068] In order to further illustrate the present invention, the following examples are provided for detailed description. The experimental raw materials used in the following examples of the present invention are all common commercially available products.

[0069] Example 1

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

[0071] (1) The temperature of the reactor was controlled at 60°C, 1500 g of deionized water was added to the reactor, 342.5 g (1.5 mol) of dodecanedioic acid was added at one time, and stirred for 30 min. 340.6 g (1.7 mol) of dodecanediamine was added to the reactor in three portions (80 g, 120 g, and 140.6 g each time). After all the additions were made, stirring was continued for 1 h. When the pH value of the reaction solution reached 8, the reaction was stopped, the liquid in the reactor was filtered, and the filtrate was collected to obtain nylon 1212 crude salt.

[0072] (2) The crude nylon 1212 salt obtained in step (1) is added to a purification kettle, and 1200 g of anhydrous ethanol is added. The temperature of the purification kettle is controlled at 50° C., stirred for 5 h, allowed to stand at room temperature for 2 h, filtered, and the filtrate is collected. This process is repeated twice, and the filtrate is vacuum dried at 40° C. for 48 h to obtain refined nylon 1212 salt;

[0073] (3) Add the refined nylon 1212 salt obtained in step (2), 0.38 g phosphoric acid, 0.95 g IRGANOX1010 and 1.52 g 1,6-hexanediol into the polymerization reactor, replace the air in the reactor with nitrogen, control the pressure in the reactor at 0.03 MPa, heat the reactor to control the temperature at 185°C, and react for 1.5 h. The reactor is heated to 230°C, the pressure of the polymerization reactor reaches 1.3 MPa, and the reaction is continued for 50 min; the temperature is continued to rise to 270°C, the air is vented to normal pressure, and then negative pressure is started, and vacuum is drawn to a vacuum degree of 5 Pa, and the negative pressure time is 20 min;

[0074] (4) Under nitrogen protection, the material in the polymerization kettle is discharged through the spinneret hole, and then drawn into strips and pelletized 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 FIG. Figure 1 The molecular weight statistics are shown in Table 1 below: the number average molecular weight is 41.2 kg / mol, and the molecular weight distribution index is 2.87.

[0076] The XRD and DSC diagrams of the ultra-high molecular weight nylon 1212 resin provided in this embodiment are shown in Figures 1 and 2. Figure 2 and Figure 3 As shown by Figure 2 It can be seen that the obtained nylon 1212 has characteristic nylon peaks at 6.15°, 21.21° and 39.45°, and there are two sharp peaks at 6.15° and 21.21°, indicating that the nylon of the invention has excellent crystallization properties. Figure 3 It can be seen that the melting point is 186.5°C.

[0077] Example 2

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

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

[0080] (2) Add the crude nylon 1212 salt prepared in (1) into a purification kettle, add 1150 g of anhydrous ethanol, control the temperature of the purification kettle at 70°C, stir for 3 h, let stand at room temperature for 2 h, filter, and collect the filtrate. Repeat this process twice, and dry the filtrate at 60°C under vacuum for 24 h to obtain refined nylon 1212 salt;

[0081] (3) Add refined nylon 1212 salt, 0.56 g phosphorous acid, 1.85 g IRGANOX1076 and 2.5 g 1,10-decanedioic acid to the polymerization reactor, replace the air in the reactor with carbon dioxide gas, control the pressure in the reactor at 0.8 MPa, heat the reactor to control the temperature at 210°C, and react for 0.5 h. The reactor is heated to 250°C, the pressure of the polymerization reactor reaches 1.8 MPa, and the reaction is continued for 35 min; the temperature is continued to rise to 290°C, the air is vented to normal pressure, and then negative pressure is started, and vacuum is drawn to a vacuum degree of 150 Pa, and the negative pressure time is 50 min;

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

[0083] Example 3

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

[0085] (1) The temperature of the reactor was controlled at 65°C, 800 g of deionized water was added to the reactor, 228.5 g of dodecanedioic acid was added at one time, and stirred for 40 min. 219.5 g of dodecanediamine was added to the reactor in three portions (50 g, 70 g, and 99.5 g each time). After all the additions were made, stirring was continued for 2 h. When the pH value of the reaction solution reached 7.5, the reaction was stopped, the liquid in the reactor was filtered, and the filtrate was collected to obtain nylon 1212 crude salt.

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

[0087] (3) Add the refined nylon 1212 salt obtained in step (2), 1.25 g sodium phosphite, 0.79 g IRGANOX1035 and 3.1 g 1,10-decanediamine to the polymerization reactor, replace the air in the reactor with argon, control the pressure in the reactor at 0.2 MPa, heat the reactor to control the temperature at 190°C, and react for 1 hour. The reactor is heated to 240°C, the pressure of the polymerization reactor reaches 1.5 MPa, and the reaction is continued for 40 minutes; the temperature is continued to rise to 280°C, the air is vented to normal pressure, and then negative pressure is started, and vacuum is drawn to a vacuum degree of 100 Pa, and the negative pressure time is 30 minutes;

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

[0089] Example 4

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

[0091] (1) The temperature of the reactor was controlled at 68°C, deionized water was added to the reactor, 182.6 g of dodecanedioic acid was added at one time, and stirred for 35 min. 206.5 g of dodecanediamine was added to the reactor in three portions (40 g, 60 g, and 106.5 g each time). After all the additions were made, stirring was continued for 3 h. When the pH value of the reaction liquid reached 8, the reaction was stopped, the liquid in the reactor was filtered, and the filtrate was collected to obtain nylon 1212 crude salt.

[0092] (2) The crude nylon 1212 salt obtained in step (1) was added to a purification kettle, and 510 g of anhydrous ethanol was added. The temperature of the purification kettle was controlled at 55° C., stirred for 4.5 h, left at room temperature for 2 h, filtered, and the filtrate was collected. This process was repeated twice, and the filtrate was vacuum dried at 55° C. 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, control the pressure in the reactor at 0.5 MPa, heat the reactor to control the temperature at 200°C, and react for 1.5 hours. The reactor is heated to 235°C, the pressure of the polymerization reactor reaches 1.4 MPa, and the reaction is continued for 45 minutes; the temperature is continued to rise to 285°C, the air is vented to normal pressure, and then negative pressure is started, and vacuum is drawn, the vacuum degree reaches 50 Pa, and the negative pressure time is 35 minutes;

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

[0095] Example 5

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

[0097] (1) The temperature of the reactor was controlled at 70°C, 1100 g of deionized water was added to the reactor, 274.5 g of dodecanedioic acid was added at one time, and stirred for 40 min. 210.4 g of dodecanediamine was added to the reactor in three portions (30 g, 70 g, and 110.4 g each time). After all the additions were made, stirring was continued for 2.5 h. When the pH value of the reaction solution reached 7.5, the reaction was stopped, the liquid in the reactor was filtered, and the filtrate was collected to obtain nylon 1212 crude salt.

[0098] (2) The crude nylon 1212 salt obtained in step (1) was added to a purification kettle, and 500 g of anhydrous ethanol was added. The temperature of the purification kettle was controlled at 55° C., stirred for 3.5 h, left at room temperature for 2 h, filtered, and the filtrate was collected. This process was repeated twice, and the filtrate was vacuum dried at 50° C. for 30 h to obtain refined nylon 1212 salt;

[0099] (3) Add the nylon 1212 salt refined in step (2), 0.35g of pyrophosphorous acid, 0.86g of IRGANOX1135 and 1.65g of 1,16-diaminohexadecane to the polymerization reactor, replace the air in the reactor with nitrogen, control the pressure in the reactor at 0.5 MPa, heat the reactor to control the temperature at 198°C, and react for 1.5 hours. The reactor is heated to 245°C, the pressure of the polymerization reactor reaches 1.7 MPa, and the reaction is continued for 40 minutes; the temperature is continued to rise to 280°C, the air is vented to normal pressure, and then negative pressure is started, and vacuum is drawn to a vacuum degree of 100 Pa, and the negative pressure time is 35 minutes;

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

[0101] Example 6

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

[0103] (1) The temperature of the reactor was controlled at 63 °C, deionized water was added to the reactor, 410.9 g of dodecanedioic acid was added at one time, and stirred for 35 min. 398.5 g of dodecanediamine was added to the reactor in three portions (100 g, 130 g, and 168.5 g each time). After all the additions were made, stirring was continued for 3 h. When the pH value of the reaction liquid reached 7.8, the reaction was stopped, the liquid in the reactor was filtered, and the filtrate was collected to obtain nylon 1212 crude salt.

[0104] (2) The crude nylon 1212 salt obtained in step (1) is added to a purification kettle, and 1400 g of anhydrous ethanol is added. The temperature of the purification kettle is controlled at 60° C., stirred for 4 h, left at room temperature for 2 h, filtered, and the filtrate is collected. This process is repeated twice, and the filtrate is vacuum dried at 50° C. for 40 h to obtain refined nylon 1212 salt;

[0105] (3) Add the nylon 1212 salt refined in step (2), 1.75 g of phosphorous acid, 1.88 g of IRGANOX1520 and 2.3 g of 1,7-heptanedioic acid to the polymerization reactor, replace the air in the reactor with carbon dioxide, control the pressure in the reactor at 0.4 MPa, heat the reactor to control the temperature at 200°C, and react for 1 hour. The reactor is heated to 235°C, the pressure of the polymerization reactor reaches 1.4 MPa, and the reaction is continued for 45 minutes; the temperature is continued to rise to 275°C, the air is vented to normal pressure, and then negative pressure is started, and vacuum is drawn to a vacuum degree of 80 Pa, and the negative pressure time is 40 minutes;

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

[0107] Example 7

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

[0109] The preparation method was similar to that in Example 1, except that the anhydrous ethanol in step (1) was replaced by methanol, and the other reaction conditions remained unchanged.

[0110] Example 8

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

[0112] The preparation method was similar to that in Example 1, the only difference was that the anhydrous ethanol in step (1) was replaced by isopropanol, and the other reaction conditions remained unchanged.

[0113] Comparative Example 1

[0114] This comparative example provides a nylon 1212, and its preparation method is as follows:

[0115] The polymerization was carried out using the following polymerization method and the raw material ratios in Example 1.

[0116] (1) Add 342.5 g of dodecanedioic acid, 340.6 g of dodecanediamine, 0.38 g of phosphoric acid, 0.95 g of IRGANOX1010 and 1.52 g of 1,6-hexanediol into the polymerization kettle, replace the air in the reactor with nitrogen, control the pressure in the reactor at 0.03 MPa, heat the reactor to control the temperature at 185°C, and react for 1.5 h. The reactor temperature is raised to 230°C, the pressure of the polymerization kettle reaches 1.3 MPa, and the reaction is continued for 50 min;

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

[0118] (3) Under nitrogen protection, the material in the polymerization kettle is discharged through the spinneret hole, and then drawn into strips and pelletized underwater to obtain nylon 1212 resin.

[0119] The GPC results of nylon 1212 resin provided in this comparative example are shown in FIG. 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, and its preparation method is as follows:

[0122] (1) Add 342.5 g of dodecanedioic acid to 200 g of anhydrous ethanol at room temperature and heat to 60°C to form a dispersion. Then add 340.6 g of dodecanediamine to the polymerization kettle and continue stirring for 1.5 h to obtain a nylon 1212 salt solution. Filter the solution, collect the filtrate, and vacuum dry it 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-hexanediol were added to a polymerization reactor. The air in the reactor was replaced with high-purity nitrogen. The temperature was raised to 195°C. The pressure in the reactor reached 1.5 MPa. After maintaining the temperature for 1.5 h, the air was slowly released to normal pressure. Then, the temperature was raised to 250°C and vacuum was started to be reduced to 50 KPa.

[0124] (3) Under nitrogen protection, the material in the polymerization kettle is discharged through the spinneret hole, and then drawn into strips and pelletized underwater to obtain nylon 1212 resin.

[0125] Performance Testing

[0126] (1) Mechanical properties

[0127] In the 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 and the injection pressure was 600 kgf / cm 2 The injection molded samples were obtained under the conditions of 2.0 s injection time and 200°C mold temperature, and the mechanical strength test was carried out in an absolutely dry state.

[0128] (2) Molecular weight and its distribution

[0129] 10 mg of the sample nylon 1212 resin obtained in the above examples and comparative examples was dissolved in 10 g of hexafluoroisopropanol to prepare a nylon solution, and a GPC test was performed.

[0130] All performance test results of the samples obtained in Examples 1 to 8 and Comparative Examples 1 to 2 are shown in Table 1 below:

[0131] Table 1

[0132]

[0133] As can be seen from the data in Table 1, the tensile strength of the nylon 1212 resin provided by the present 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 the present invention can reach 38.5-42.5 g / mol, and the molecular weight distribution is narrow, 2.63-2.93, while the molecular weight of the comparative example is lower, 9.8-24.7 kg / mol, and the molecular weight distribution is wider, 4.41-5.81. This is because the present invention obtains a high-purity nylon 1212 monomer salt, and can prepare an ultra-high molecular weight nylon 1212 resin, while the purity of the nylon 1212 monomer salt of the comparative example is lower, and more impurities make it difficult to obtain a high molecular weight nylon 1212 resin.

[0134] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing ultra-high molecular weight long carbon chain nylon 1212 resin, characterized in that: The following steps are involved: S1: purifying nylon 1212 crude 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: The refined nylon 1212 salt, the catalyst and the molecular weight regulator are polymerized to obtain an ultra-high molecular weight long carbon chain nylon 1212 resin.

2. The preparation method according to claim 1, characterized in that: The purification is as follows: after mixing nylon 1212 crude salt with a polar solvent, stirring at 50-70° C. for 3-5 h, and standing at room temperature for 1-3 h; The purification is performed 1 to 3 times.

3. The preparation method according to claim 1 or 2, characterized in that: After the purification is completed, the steps of filtering and drying are also included; The drying temperature is 40-60°C and the drying time is 24-48 hours.

4. The preparation method according to any one of claims 1 to 3, characterized in that The catalyst is selected from any one or more of phosphoric acid, phosphorous acid, sodium phosphite, sodium hypophosphite or pyrophosphorous acid; 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-butanediol, 1,6-hexanediol, 1,7-heptanedioic acid, 1,8-octanedioic acid, 1,9-nonanediol, 1,10-decanedioic acid, 1,11-undecanedioic acid, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanedioic acid or 1,16-hexadecanedioic acid; The diamine is selected from any one or more of 1,10-decanediamine, 1,11-undecanediamine or 1,16-diaminohexadecane.

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

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

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

8. The preparation method according to any one of claims 1 to 7, characterized in that The polymerization reaction is: At 185~210℃, 0.03~0.8 MPa, react for 0.5~1.5 h; Raise the temperature to 230-250°C and continue the reaction at 1.3-1.8 MPa for 35-50 min; Continue to raise the temperature to 270~290℃ and react for 20~50 min under a vacuum degree of 50~150 Pa.

9. The preparation method according to any one of claims 1 to 8, characterized in that The nylon 1212 crude salt is obtained by reacting dodecanedioic acid and dodecanediamine at 60-70°C.

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

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