Polyamide material and preparation method thereof

Abstract

The invention relates to the field of high polymer materials, and discloses a polyamide material and a preparation method thereof. The preparation method of the polyamide material comprises the following steps: in the presence of a polycondensation catalyst and a solvent, nylon salt and a tackifying additive are subjected to a polycondensation reaction, the tackifying additive has a structure represented by a formula (1), and in the formula (1), n is an integer of 2-10, and m is an integer of 2-10. According to the polyamide material provided by the invention, the tackifying additive is directly added into the raw materials for reaction, so that the post-processing modification process adopted in the prior art is avoided, the polyamide material has better strength and viscosity, and the process complexity and energy loss are reduced. # imgabs0 #

Description

Technical Field

[0001] The invention relates to the field of polymer materials, and in particular to a polyamide material and a preparation method thereof. Background Art

[0002] Polyamide is a general-purpose engineering plastic with high mechanical strength, good dimensional stability and excellent corrosion resistance. Compared with metals, it is lightweight and widely used in aerospace, automobiles, machinery, electronic appliances, medical equipment and other fields. In order to meet different application scenarios and fields, polyamide materials need to be modified to improve their performance. High-viscosity polyamide has a higher molecular weight, which further improves its mechanical properties and can obtain higher strength to meet the requirements of high-strength application materials.

[0003] At present, the main method for preparing high-viscosity polyamide materials is solid phase viscosity enhancement, which prolongs the reaction time of solid phase final polycondensation to increase the molecular weight, thereby increasing the viscosity of the polyamide. This method requires long-term high-temperature reaction, which consumes a lot of reaction energy. At the same time, side reactions are inevitable, affecting the color and performance of the material. High-viscosity polyamide materials can also be obtained by adding chain extenders in post-processing processes such as screw extrusion, but this method increases the complexity of the process and increases the overall cost. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and to provide a polyamide material and a preparation method thereof. The polyamide material prepared by the preparation method of the polyamide material of the present invention has better strength and viscosity, and by adding a specific viscosity-increasing additive to the raw material for reaction, the post-processing modification process used in the prior art is avoided, thereby reducing the process complexity and energy loss.

[0005] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a polyamide material, wherein the method comprises: in the presence of a polycondensation catalyst and a solvent, subjecting a nylon salt and a viscosity-enhancing additive to a polycondensation reaction, wherein the viscosity-enhancing additive has a structure as shown in formula (1),

[0006]

[0007] In formula (1), n ​​is an integer of 2-10, and m is an integer of 2-10.

[0008] Preferably, in formula (1), n ​​is an integer of 2-8, and m is an integer of 2-8.

[0009] Preferably, the polycondensation catalyst is at least one of sodium hypophosphite, sodium phosphate, phosphoric acid, potassium phosphate and potassium phosphite, preferably at least one of sodium hypophosphite, sodium phosphate and phosphoric acid, more preferably, the polycondensation catalyst is sodium hypophosphite.

[0010] Preferably, the nylon salt is a neutralization reaction product of a diamine having 6 to 20 carbon atoms and a dibasic acid having 6 to 20 carbon atoms.

[0011] Preferably, the solvent is at least one of water, dimethylacetamide and N-methylpyrrolidone, preferably water.

[0012] The added amount of the solvent is 10-100% by weight of the nylon salt, preferably 25-40% by weight.

[0013] The amount of the viscosity enhancing additive added is 0.1-2% by weight, preferably 0.75-1.5% by weight, of the nylon salt.

[0014] The amount of the polycondensation catalyst added is 0.05-1% by weight, preferably 0.1-0.5% by weight, of the nylon salt.

[0015] Preferably, the polycondensation reaction is carried out in the presence of an antioxidant.

[0016] The antioxidant is at least one of antioxidant 1098, antioxidant 1010, antioxidant 168, antioxidant 1178 and antioxidant H10, preferably antioxidant 1010.

[0017] Preferably, the antioxidant is added in an amount of 0.1-2 wt %, preferably 0.5-1 wt % of the nylon salt.

[0018] Preferably, the polycondensation reaction includes a first stage polycondensation reaction and a second stage polycondensation reaction.

[0019] Preferably, the first-stage polycondensation reaction and / or the second-stage polycondensation reaction is carried out under an inert atmosphere.

[0020] Preferably, the conditions of the first stage polycondensation reaction include: reaction temperature of 180-210°C, preferably 190-200°C, reaction pressure of 1.2-1.5MPa, preferably 1.3-1.4MPa, reaction time of 4-10h, preferably 6-8h.

[0021] Preferably, the conditions of the second stage polycondensation reaction include: reaction temperature of 230-260° C., preferably 240-250° C., reaction time of 1-6 h, preferably 2-4 h.

[0022] The second aspect of the present invention provides a polyamide material prepared by the method for preparing the polyamide material according to the first aspect of the present invention.

[0023] The polyamide material prepared by the above technical scheme has better strength and viscosity. By directly adding the viscosity-increasing additive into the raw material for reaction, the post-processing modification process used in the prior art is avoided, thereby reducing the process complexity and energy loss. DETAILED DESCRIPTION

[0024] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0025] It should also be noted that the various specific technical features described in the following specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0026] In addition, the various embodiments of the present invention may be arbitrarily combined as long as they do not violate the concept of the present invention. The technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0027] According to a first aspect of the present invention, a method for preparing a polyamide material is provided, wherein the method comprises: in the presence of a polycondensation catalyst and a solvent, subjecting a nylon salt and a viscosity-enhancing additive to a polycondensation reaction, wherein the viscosity-enhancing additive has a structure as shown in formula (1),

[0028]

[0029] In formula (1), n ​​is an integer of 2-10, and m is an integer of 2-10.

[0030] Preferably, n is an integer of 2-8, and m is an integer of 2-8.

[0031] Specific examples of n include 2, 3, 4, 5, 6, 7, and 8.

[0032] Specific examples of m include 2, 3, 4, 5, 6, 7, and 8.

[0033] As specific examples of the viscosity-increasing additive, the following compounds can be cited: compounds wherein n is 2 and m is 2 in formula (1); compounds wherein n is 2 and m is 3 in formula (1); compounds wherein n is 2 and m is 4 in formula (1); compounds wherein n is 2 and m is 5 in formula (1); compounds wherein n is 2 and m is 6 in formula (1); compounds wherein n is 2 and m is 7 in formula (1); compounds wherein n is 2 and m is 8 in formula (1); compounds wherein n is 3 and m is 3 in formula (1); compounds wherein n is 3 and m is 4 in formula (1); compounds wherein n is 3 and m is 5 in formula (1); compounds wherein n is 3 and m is 6 in formula (1); compounds wherein n is 3 and m is 7 in formula (1); compounds wherein n is 3 and m is 8 in formula (1); , the compound wherein n is 4 and m is 4; the compound wherein n is 4 and m is 5 in formula (1); the compound wherein n is 4 and m is 6 in formula (1); the compound wherein n is 4 and m is 7 in formula (1); the compound wherein n is 4 and m is 8 in formula (1); the compound wherein n is 5 and m is 5 in formula (1); the compound wherein n is 5 and m is 6 in formula (1); the compound wherein n is 5 and m is 7 in formula (1); the compound wherein n is 5 and m is 8 in formula (1); the compound wherein n is 6 and m is 6 in formula (1); the compound wherein n is 6 and m is 7 in formula (1); the compound wherein n is 6 and m is 8 in formula (1); the compound wherein n is 7 and m is 7 in formula (1); the compound wherein n is 7 and m is 8 in formula (1); the compound wherein n is 8 and m is 8 in formula (1), etc.

[0034] According to the present invention, in order to improve the efficiency of the polycondensation reaction, preferably, the polycondensation catalyst is at least one of sodium hypophosphite, sodium phosphate, phosphoric acid, potassium phosphate and potassium phosphite; more preferably, the polycondensation catalyst is at least one of sodium hypophosphite, sodium phosphate and phosphoric acid; particularly preferably, the polycondensation catalyst is sodium hypophosphite.

[0035] According to the present invention, in order to improve the strength and durability of the polyamide material, preferably, the nylon salt is a neutralization reaction product of a diamine having 6-20 carbon atoms and a dibasic acid having 6-20 carbon atoms; more preferably, the nylon salt is a neutralization reaction product of a diamine having 10-14 carbon atoms and a dibasic acid having 10-14 carbon atoms.

[0036] Specific examples of diamines having 6 to 20 carbon atoms include at least one of hexamethylenediamine, heptamethylenediamine, octanediamine, nonamethylenediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, pentamethylenediamine, hexadecanediamine, octadecanediamine, and eicosanediamine. Among them, at least one of octanediamine, nonamethylenediamine, decanediamine, undecanediamine, and dodecanediamine is preferred, and decanediamine and / or dodecanediamine are more preferred.

[0037] Specific examples of dibasic acids having 6 to 20 carbon atoms include, for example, at least one of adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, octadecandioic acid and eicosandioic acid. Among them, preferably at least one of suberic acid, azelaic acid, sebacic acid, undecanedioic acid and dodecanedioic acid, more preferably sebacic acid and / or dodecanedioic acid.

[0038] Specifically, the nylon salt is at least one of 1012 salt, 1212 salt, 1010 salt and 1313 salt.

[0039] The 1012 salt is a neutralization reaction product of a diamine having 10 carbon atoms and a dibasic acid having 12 carbon atoms.

[0040] The 1212 salt is a neutralization reaction product of a diamine having 12 carbon atoms and a dibasic acid having 12 carbon atoms.

[0041] The 1010 salt is a neutralization reaction product of a diamine having 10 carbon atoms and a dibasic acid having 10 carbon atoms.

[0042] The 1313 salt is a neutralization reaction product of a diamine having 13 carbon atoms and a dibasic acid having 13 carbon atoms.

[0043] In the present invention, the nylon salt can be prepared according to conventional synthesis methods in the art, or can be obtained commercially.

[0044] According to the present invention, for solubility considerations, preferably, the solvent is at least one of water, dimethylacetamide and N-methylpyrrolidone; more preferably, the solvent is water; further preferably, the water is water from which oxygen has been removed by nitrogen bubbling.

[0045] According to the present invention, the amount of the solvent can be selected according to the amount of the nylon salt. Preferably, the amount of the solvent added is 10-100 wt % of the nylon salt; more preferably, the amount of the solvent added is 25-40 wt % of the nylon salt.

[0046] According to the present invention, the amount of the viscosity-enhancing additive can be selected according to the amount of the nylon salt, and the viscosity and strength of the final polyamide material can be adjusted by adding different amounts. For the sake of economy and final product performance, preferably, the amount of the viscosity-enhancing additive added is 0.1-2 weight % of the nylon salt; more preferably, the amount of the viscosity-enhancing additive added is 0.75-1.5 weight % of the nylon salt.

[0047] In a preferred embodiment of the present invention, the values ​​of n and m in formula (1) of the viscosity enhancing additive are the same as or similar to the number of carbon atoms in the nylon salt, thereby improving the uniformity of the nylon chain segment and the stability of product performance.

[0048] According to the present invention, the amount of the polycondensation catalyst can be selected according to the amount of the nylon salt. Preferably, the amount of the polycondensation catalyst added is 0.05-1 wt % of the nylon salt; more preferably, the amount of the polycondensation catalyst added is 0.1-0.5 wt % of the nylon salt.

[0049] According to the present invention, in order to delay or prevent the polymer from being oxidized and aging, the polycondensation reaction is carried out in the presence of an antioxidant.

[0050] The antioxidant may be at least one of antioxidant 1098, antioxidant 1010, antioxidant 168, antioxidant 1178 and antioxidant H10; preferably, the antioxidant is antioxidant 1010.

[0051] The amount of the antioxidant can be selected according to the amount of the nylon salt. Preferably, the amount of the antioxidant added is 0.1-2% by weight of the nylon salt, and more preferably 0.5-1% by weight.

[0052] According to the present invention, preferably, the polycondensation reaction includes a first stage polycondensation reaction and a second stage polycondensation reaction.

[0053] In order to isolate from air and prevent oxidation, preferably, the first stage polycondensation reaction and / or the second stage polycondensation reaction are carried out under an inert atmosphere. Preferably, the gas of the inert atmosphere is selected from one of nitrogen, argon and carbon dioxide; more preferably, the gas of the inert atmosphere is carbon dioxide.

[0054] According to the present invention, preferably, the conditions of the first stage polycondensation reaction include: reaction temperature of 180-210°C, reaction time of 4-10h, and reaction pressure of 1.2-1.5MPa; more preferably, the conditions of the first stage polycondensation reaction include: reaction temperature of 190-200°C, reaction time of 6-8h, and reaction pressure of 1.3-1.4MPa.

[0055] According to the present invention, preferably, the conditions of the second stage polycondensation reaction include: reaction temperature of 230-260°C, reaction time of 1-6h; more preferably, the conditions of the second stage polycondensation reaction include: reaction temperature of 240-250°C, reaction time of 2-4h.

[0056] According to a second aspect of the present invention, a polyamide material prepared by the method for preparing the polyamide material according to the first aspect of the present invention is provided.

[0057] The polyamide material of the present invention has better strength and viscosity. By directly adding a viscosity-increasing additive into the raw material for reaction, the post-processing modification process used in the prior art is avoided, and the process complexity and energy loss are reduced.

[0058] The present invention will be described in detail below through examples, but the present invention is not limited to the following examples and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0059] In the following examples and comparative examples, the sources of reagents are commercially available unless otherwise specified.

[0060] Preparation Example 1

[0061] Preparation method of nylon 1212 salt: (1) add 1151.5g of dodecanedioic acid (purchased from Sinopharm) and 4500g of ethanol to a neutralization kettle, heat to 70°C to dissolve, and keep for 20 minutes; (2) add 1001.5g of dodecanediamine (purchased from Sinopharm) and 1000g of ethanol to a dissolution kettle, heat to 60°C to dissolve, and keep for 20 minutes; (3) use a peristaltic pump to drop the dodecanediamine ethanol solution into the diacid solution kettle, stir and react, the reaction temperature is controlled at 70°C, continue to react for 2.0 hours after adding the materials, cool the neutralization kettle to reduce the temperature to below 25°C, filter the neutralized solution through a filter, and dry in a drying oven to obtain nylon 1212 salt.

[0062] Preparation Example 2

[0063] Preparation method of nylon 1012 salt: (1) add 1151.5g of dodecane dicarboxylic acid (purchased from Sinopharm) and 4500g of ethanol to a neutralization kettle, heat to 70°C to dissolve, and keep for 20 minutes; (2) add 861.5g of decanediamine (purchased from Sinopharm) and 900g of ethanol to a dissolution kettle, heat to 60°C to dissolve, and keep for 20 minutes; (3) use a peristaltic pump to drop the dodecane diamine ethanol solution into the diacid solution kettle, stir and react, the reaction temperature is controlled at 70°C, continue to react for 2.0 hours after adding the materials, cool the neutralization kettle to reduce the temperature to below 25°C, filter the neutralized solution through a filter, and dry in a drying oven to obtain nylon 1012 salt.

[0064] Preparation Example 3

[0065] Preparation method of nylon 1010 salt: (1) add 1011.25g of sebacic acid (purchased from Sinopharm) and 4000g of ethanol to a neutralization kettle, heat to 70°C to dissolve, and keep for 20 minutes; (2) add 861.5g of decanediamine (purchased from Sinopharm) and 900g of ethanol to a dissolution kettle, heat to 60°C to dissolve, and keep for 20 minutes; (3) use a peristaltic pump to drop the ethanol solution of dodecanediamine into the diacid solution kettle, stir and react, the reaction temperature is controlled at 70°C, continue to react for 2.0 hours after adding the materials, cool the neutralization kettle to reduce the temperature to below 25°C, filter the neutralized solution through a filter, and dry it in a drying oven to obtain nylon 1010 salt.

[0066] Preparation Example 4

[0067] Preparation method of nylon 1313 salt: (1) add 1221.65g of sebacic acid (purchased from Sinopharm) and 6000g of ethanol to a neutralization kettle, heat to 70°C to dissolve, and keep for 20 minutes; (2) add 1071.95g of decanediamine (purchased from Sinopharm) and 1000g of ethanol to a dissolution kettle, heat to 60°C to dissolve, and keep for 20 minutes; (3) use a peristaltic pump to drop the ethanol solution of dodecanediamine into the diacid solution kettle, stir and react, the reaction temperature is controlled at 70°C, continue to react for 2.0 hours after adding the materials, cool the neutralization kettle to reduce the temperature to below 25°C, filter the neutralized solution through a filter, and dry it in a drying oven to obtain nylon 1313 salt.

[0068] Example 1

[0069] Polyamide preparation

[0070] (1) 600 g of nylon 1212 salt, 200 g of water, 0.6 g of sodium hypophosphite and 3 g of antioxidant 1010 were mixed evenly and added to a 2 L high temperature and high pressure polymerization kettle, and then the viscosity increasing additive hexamethyltriamine (purchased from Anaiji Company, the same below) was directly added in an amount of 0.125% by weight of the nylon 1212 salt, and carbon dioxide was charged to replace the air;

[0071] (2) Heating for 1 hour to 200°C, the pressure in the autoclave increased to 1.4 MPa, and this temperature and pressure were maintained for 2 hours;

[0072] (3) Slowly release water vapor and the pressure in the kettle drops to normal pressure within 2 hours;

[0073] (4) After the reaction temperature is maintained at 250° C. under normal pressure for 2 hours, stirring is stopped, the discharge valve is opened, nitrogen is filled in, the material flows out through the injection head, and pelletized after cooling to prepare a polyamide product.

[0074] Example 2

[0075] Polyamide preparation

[0076] The preparation was carried out according to the method of Example 1, except that the addition amount of the viscosity-increasing additive hexamethyltriamine was 0.25% by weight of the nylon 1212 salt. The polyamide product was prepared in the same manner, and the results are shown in Table 1.

[0077] Example 3

[0078] The preparation was carried out according to the method of Example 1, except that the addition amount of the viscosity-increasing additive hexamethyltriamine was 0.5% by weight of the nylon 1212 salt. The polyamide product was prepared in the same manner, and the results are shown in Table 1.

[0079] Example 4

[0080] The preparation was carried out according to the method of Example 1, except that the addition amount of the viscosity-increasing additive hexamethyltriamine was 1 weight % of the nylon 1212 salt. The polyamide product was prepared in the same manner, and the results are shown in Table 1.

[0081] Example 5

[0082] The preparation was carried out according to the method of Example 1, except that the addition amount of the viscosity-increasing additive hexamethyltriamine was 2% by weight of the nylon 1212 salt. The results are shown in Table 1.

[0083] Example 6

[0084] (1) 600 g of nylon 1012 salt, 200 g of water, 0.6 g of sodium hypophosphite and 3 g of antioxidant 1010 were mixed uniformly and added to a 2 L high temperature and high pressure polymerization kettle, and then the viscosity increasing additive hexamethyltriamine was directly added in an amount of 0.125% by weight of the nylon 1012 salt, and carbon dioxide was charged to replace the air;

[0085] (2) Heating for 1 hour to 200°C, the pressure in the autoclave increased to 1.4 MPa, and this temperature and pressure were maintained for 2 hours;

[0086] (3) Slowly release water vapor and the pressure in the kettle drops to normal pressure within 2 hours;

[0087] (4) After the reaction temperature is maintained at 250° C. under normal pressure for 2 hours, stirring is stopped, the discharge valve is opened, nitrogen is filled in, the material flows out through the injection head, and pelletized after cooling to prepare a polyamide product.

[0088] Example 7

[0089] The preparation was carried out according to the method of Example 6, except that the addition amount of the viscosity-increasing additive hexamethyltriamine was 0.25% by weight of the nylon 1012 salt. The polyamide product was prepared in the same manner, and the results are shown in Table 1.

[0090] Example 8

[0091] The preparation was carried out according to the method of Example 6, except that the addition amount of the viscosity-increasing additive hexamethyltriamine was 0.5% by weight of the nylon 1012 salt. The polyamide product was prepared in the same manner, and the results are shown in Table 1.

[0092] Example 9

[0093] The preparation was carried out according to the method of Example 6, except that the addition amount of the viscosity-increasing additive hexamethyltriamine was 1 weight % of the nylon 1012 salt. The polyamide product was prepared in the same manner, and the results are shown in Table 1.

[0094] Example 10

[0095] The preparation was carried out according to the method of Example 6, except that the addition amount of the viscosity-increasing additive hexamethyltriamine was 2% by weight of the nylon 1012 salt. The polyamide product was prepared in the same manner, and the results are shown in Table 1.

[0096] Embodiment 11

[0097] The preparation was carried out according to the method of Example 6, except that the same amount of nylon 1010 salt was used to replace nylon 1012 salt. The polyamide product was prepared in the same manner. The results are shown in Table 1.

[0098] Example 12

[0099] The preparation was carried out according to the method of Example 6, except that the same amount of nylon 1313 salt was used to replace nylon 1012 salt. The polyamide product was prepared in the same manner, and the results are shown in Table 1.

[0100] Embodiment 13

[0101] The preparation was carried out according to the method of Example 4, except that the same amount of other viscosity-increasing additives (n is 2 and m is 2 in formula (1), purchased from Sigma-Aldrich Company, CAS No. 98824-35-2) were used as the viscosity-increasing additives. The polyamide product was prepared in the same manner, and the results are shown in Table 1.

[0102] Embodiment 14

[0103] The preparation was carried out according to the method of Example 4, except that the same amount of other viscosity-increasing additives (n is 4 and m is 4 in formula (1), purchased from Enxing Biotechnology Co., Ltd. CAS No. 4427-76-3) were used as the viscosity-increasing additives. The polyamide product was prepared in the same manner, and the results are shown in Table 1.

[0104] Embodiment 15

[0105] The preparation was carried out according to the method of Example 4, except that the viscosity-increasing additive used the same amount of other viscosity-increasing additives (n is 8, m is 8 in formula (1), purchased from Sigma-Aldrich Company, CAS No. 39202-36-3), and the polyamide product was prepared in the same manner. The results are shown in Table 1.

[0106] Comparative Example 1

[0107] The preparation was carried out according to the method of Example 1, except that the viscosity-increasing additive, dihexamethylenetriamine, was not used.

[0108] Polyamide preparation

[0109] (1) 600 g of nylon 1212 salt, 200 g of water, 0.6 g of catalyst and 3 g of antioxidant were mixed evenly and added into a 2 L high temperature and high pressure polymerization reactor, and carbon dioxide was introduced to replace the air;

[0110] (2) Heating for 1 hour to 200°C, the pressure in the autoclave increased to 1.4 MPa, and this temperature and pressure were maintained for 2 hours;

[0111] (3) Slowly release water vapor and the pressure in the kettle drops to normal pressure within 2 hours;

[0112] (4) After the reaction temperature is maintained at 250° C. under normal pressure for 2 hours, stirring is stopped, the discharge valve is opened, nitrogen is filled in, the material flows out through the injection head, and pelletized after cooling to prepare a polyamide product.

[0113] Comparative Example 2

[0114] The preparation was carried out according to the method of Example 6, except that the viscosity-increasing additive, dihexamethylenetriamine, was not used.

[0115] Polyamide preparation

[0116] (1) 600 g of nylon 1012 salt, 200 g of water, 0.6 g of catalyst and 3 g of antioxidant were mixed evenly and added into a 2 L high temperature and high pressure polymerization reactor, and carbon dioxide was introduced to replace the air;

[0117] (2) Heating for 1 hour to 200°C, the pressure in the autoclave increased to 1.4 MPa, and this temperature and pressure were maintained for 2 hours;

[0118] (3) Slowly release water vapor and the pressure in the kettle drops to normal pressure within 2 hours;

[0119] (4) After the reaction temperature is maintained at 250° C. under normal pressure for 2 hours, stirring is stopped, the discharge valve is opened, nitrogen is filled in, the material flows out through the injection head, and pelletized after cooling to prepare a polyamide product.

[0120] Comparative Example 3

[0121] The preparation was carried out according to the method of Example 4, except that DuPont AD1032 tackifier having the same content of hexamethyltriamine as that in Example 1 was added, and a polyamide product was prepared in the same manner. The results are shown in Table 1.

[0122] Table 1

[0123]

[0124] As shown in Table 1, by comparing Examples 1-5 with Comparative Example 1 and Examples 6-10 with Comparative Example 2, it can be seen that the present invention can significantly improve the molecular weight, viscosity and tensile strength by adding a viscosity-increasing additive.

[0125] By comparing Examples 1-5 with Examples 6-10, it can be seen that nylon 1012 has a better effect of improving molecular weight, viscosity and tensile strength.

[0126] By comparing Example 4 with Examples 13, 14 and 15, it can be seen that since the values ​​of n and m in formula (1) of the thickening additive are the same as the number of carbon atoms in the nylon salt, the effect of the thickening additive in Example 4 is better than other similar thickening additives.

[0127] By comparing Example 4 with Comparative Example 3, it can be seen that only by using the viscosity-increasing additive with a specific structure of the present invention can the effects of increasing the molecular weight, viscosity and tensile strength be achieved.

[0128] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a polyamide material, characterized in that: The method comprises the steps of: subjecting a nylon salt and a viscosity-enhancing additive to a polycondensation reaction in the presence of a polycondensation catalyst and a solvent, wherein the viscosity-enhancing additive has a structure shown in formula (1), In formula (1), n ​​is an integer of 2-10, and m is an integer of 2-10.

2. The method according to claim 1, wherein: In formula (1), n ​​is an integer of 2-8, and m is an integer of 2-8.

3. The method according to claim 1, wherein: The polycondensation catalyst is at least one of sodium hypophosphite, sodium phosphate, phosphoric acid, potassium phosphate and potassium phosphite, preferably at least one of sodium hypophosphite, sodium phosphate and phosphoric acid, more preferably sodium hypophosphite.

4. The method according to claim 1, wherein: The nylon salt is a neutralization reaction product of a diamine having 6 to 20 carbon atoms and a dibasic acid having 6 to 20 carbon atoms.

5. The method according to claim 1, wherein: The solvent is at least one of water, dimethylacetamide and N-methylpyrrolidone, preferably water.

6. The method according to any one of claims 1 to 5, wherein: The added amount of the solvent is 10-100% by weight of the nylon salt, preferably 25-40% by weight.

7. The method according to any one of claims 1 to 5, wherein: The amount of the viscosity enhancing additive added is 0.1-2% by weight, preferably 0.75-1.5% by weight, of the nylon salt.

8. The method according to any one of claims 1 to 5, wherein: The amount of the polycondensation catalyst added is 0.05-1% by weight, preferably 0.1-0.5% by weight, of the nylon salt.

9. The method according to any one of claims 1 to 5, wherein: The polycondensation reaction is carried out in the presence of an antioxidant.

10. The method according to claim 9, wherein: The antioxidant is at least one of antioxidant 1098, antioxidant 1010, antioxidant 168, antioxidant 1178 and antioxidant H10, preferably antioxidant 1010.

11. The method according to claim 9, wherein: The antioxidant is added in an amount of 0.1-2% by weight, preferably 0.5-1% by weight, of the nylon salt.

12. The method according to any one of claims 1 to 5, wherein: The polycondensation reaction includes a first-stage polycondensation reaction and a second-stage polycondensation reaction; The first stage polycondensation reaction and / or the second stage polycondensation reaction is carried out under an inert atmosphere.

13. The method according to any one of claims 1 to 5, wherein: The conditions of the first stage polycondensation reaction include: reaction temperature of 180-210° C., preferably 190-200° C., reaction pressure of 1.2-1.5 MPa, preferably 1.3-1.4 MPa, reaction time of 4-10 h, preferably 6-8 h.

14. The method according to any one of claims 1 to 5, wherein: The conditions of the second stage polycondensation reaction include: reaction temperature of 230-260° C., preferably 240-250° C., and reaction time of 1-6 h, preferably 2-4 h.

15. The polyamide material prepared by the method for preparing the polyamide material according to any one of claims 1 to 14.

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