Anti-aging nylon modified material as well as preparation method and application thereof

Abstract

The invention discloses an anti-aging nylon modified material as well as a preparation method and application thereof, and belongs to the field of high polymer material modification. The material is composed of a nylon base material, a functionalized nano-carrier, an auxiliary antioxidant and a grafting monomer, the core is the self-made functionalized nano-carrier, the material is prepared through three steps of mesoporous sphere preparation, surface modification and anti-aging agent loading, and long-acting slow release of an anti-aging agent can be achieved; and molding through a premixing-melt blending-in-situ grafting process. The material can be used for elevator transmission system protection parts, new energy automobile parts, photovoltaic support accessories and the like, meets the requirements of strategic emerging industries, and is high in industrialization feasibility.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high polymer material modification, and particularly discloses an anti-aging nylon modified material, a preparation method and application thereof. BACKGROUND

[0002] Nylon, as an engineering plastic with excellent mechanical properties and good processability, has been widely used in elevator parts, automobile parts, electronic and electrical housings and other fields. However, the traditional nylon material faces two major problems in actual use: first, the anti-aging protection is not comprehensive, and the existing technology mainly adopts a single anti-aging agent adding method, such as adding only a hindered phenolic antioxidant to improve thermal-oxidative aging, or adding only a benzotriazole ultraviolet absorber to improve light-aging resistance, which leads to a significant decline in the protection effect of the material in a complex environment; second, the long-acting property of the anti-aging agent is poor, the anti-aging agent is dispersed in the nylon matrix in a free state, and is easy to volatilize at a processing temperature of 230-260 DEG C, and is easy to migrate to the surface of the material in a long-term use process, causing the protection performance to rapidly decrease with time, which is difficult to meet the demand for long-term service life of materials in the fields of elevators, new energy vehicles, photovoltaics and the like.

[0003] Further, in order to improve the anti-aging performance, some schemes attempt to introduce nanoparticles, but because the surface energy of the nanoparticles is high and no targeted modification is performed, the nanoparticles are easy to agglomerate in the nylon matrix, which not only cannot play a synergistic anti-aging role, but also leads to a decrease in the mechanical properties of the material, and an additional compatibilizer needs to be added, which not only increases the production cost, but also may introduce new performance short boards. At the same time, the existing modification schemes do not design in combination with the scene characteristics of strategic emerging industries, such as the need for the protection parts of the elevator transmission system and the peripheral parts of the new energy vehicle engine to withstand high temperature, the need for the photovoltaic bracket accessories to resist strong ultraviolet radiation outdoors for a long time, and the need for electronic and electrical connectors to consider cold and hot cycle stability, and the traditional material is difficult to simultaneously adapt to the above differentiated needs, which limits its application in the field of strategic emerging industries.

[0004] Further analysis shows that the core root cause of the short board of the anti-aging performance of the traditional nylon lies in the free state of the anti-aging agent. On the one hand, the free anti-aging agent cannot simultaneously achieve the synergistic protection of thermal-oxidative aging and light-aging, and the protection effect declines by more than 50% in a complex environment when a single anti-aging agent is added; on the other hand, the free anti-aging agent has weak intermolecular forces, is easy to volatilize at a high temperature of 230-260 DEG C in the process of nylon, and migrates to the surface of the material due to the concentration gradient difference in the use process, and the protection efficiency decreases by 50% after 1000 hours, which directly leads to the fact that the protection parts of the elevator transmission system, the parts of the new energy vehicle, the photovoltaic bracket and the like cannot achieve a design service life of more than 10 years.

[0005] In summary, the current nylon modification technology urgently needs to break through the basic bottleneck of "not comprehensive anti-aging protection, poor long-term effect", and solve the derived problem of "nanoparticle agglomeration, insufficient scene adaptability", to meet the application requirements of high performance, industrialization and multiple scenes. SUMMARY

[0006] Therefore, the application provides a kind of anti-aging nylon modified material and preparation method and application, realize the long-acting slow release and uniform dispersion of anti-aging agent by designing self-made functional nano-carrier, optimize formula and process, and give consideration to material anti-aging performance, mechanical property and scene adaptability.

[0007] The technical scheme of the application is as follows: the application provides an anti-aging nylon modified material, which is composed of the following components in mass percentage: nylon base material 80%-98%, functional nano-carrier 1%-10%, auxiliary antioxidant 0.05%-0.5%, and grafting monomer 0.1%-2%. The functional nano-carrier is a composite particle of mesoporous structure nanosphere loaded with anti-aging agent, and is self-made by a three-step method of "mesoporous sphere preparation-surface modification-anti-aging agent loading". The anti-aging agent contains main antioxidant and ultraviolet absorber, and can resist both thermal oxidative aging and light aging. The application also provides a preparation method of the material, which realizes uniform compounding of each component by a process of "premixing-melt blending-in situ grafting", and the application of the material in parts of new field.

[0008] In some embodiments, the nylon base material is selected from PA6 or PA66, and the relative viscosity of PA66 is 2.4-2.8. This viscosity range can balance the melt flowability and mechanical strength of the material, avoiding defects in part forming due to excessively low viscosity, or processing difficulty due to excessively high viscosity.

[0009] In some embodiments, the preparation steps of the functional nano-carrier are as follows: first, mesoporous structure nanosphere preparation. Tetraethyl orthosilicate (corresponding to mesoporous silica nanosphere) or sucrose (corresponding to mesoporous carbon nanosphere) is added to an ethanol-water mixed solution, and ammonia water is added to adjust the pH to 9-10. The solution is stirred at 30-60°C for 4-8h, centrifuged and dried, and then calcined at 500-600°C for 2-4h to obtain mesoporous structure nanospheres with a particle size of 30-100nm and a pore size of 3-15nm. Second, surface modification. The mesoporous structure nanospheres are added to an ethanol solution, and a silane coupling agent (in an amount of 3%-10% of the mass of the mesoporous structure nanospheres) is added. The solution is stirred at 60-90°C for 1-4h, and the modified nanospheres with surface-grafted amino, epoxy or carboxyl groups are obtained after centrifugation and drying. Third, anti-aging agent loading. The modified nanospheres are added to an acetone solution, and main antioxidant and ultraviolet absorber are added. The solution is stirred at 50-70°C for 3-6h, and then acetone is removed by reduced pressure distillation and dried to obtain functional nano-carriers with a total anti-aging agent loading amount of 20%-50%.

[0010] The present application solves the basic technical problems by the high load-slow release-primary compatibility triple design of the mesoporous structure nanosphere: 1. The structure of the mesoporous sphere with a pore size of 5-10 nm can simultaneously load the main antioxidant and the ultraviolet absorber, realize the double protection of thermal oxidation and light aging, and break the limitation of traditional single protection; 2. The slow release effect of the mesoporous channel can reduce the processing volatilization rate of the anti-aging agent, avoid migration and loss during use, and prolong the protection life; 3. The amino group / epoxy group modified and grafted on the surface by the silane coupling agent can preliminarily improve the interfacial bonding force between the carrier and the nylon matrix, avoid the mechanical property deterioration caused by the agglomeration of nanoparticles, and lay a foundation for subsequent derivative problem optimization.

[0011] In some embodiments, the mesoporous structure nanosphere is selected from mesoporous silica nanospheres or mesoporous carbon nanospheres, and the particle size is preferably 50-80 nm and the pore size is preferably 5-10 nm; the size parameters are verified by experiments to ensure that the nanospheres are uniformly dispersed in the nylon matrix, avoid agglomeration caused by too small particle size, or affect the mechanical properties of the material due to too large particle size.

[0012] In some embodiments, the mass ratio of the main antioxidant to the ultraviolet absorber in the anti-aging agent is 1:1-1:2, the main antioxidant is selected from hindered phenolic antioxidants (such as antioxidants 1010, 1076), and the ultraviolet absorber is selected from benzotriazole (such as UV-327, UV-326) or benzophenone (such as UV-531); the ratio and type combination can synergistically play the roles of anti-thermal oxidation and anti-light aging, and the mass ratio of 1:1-1:2 can balance the protection needs of the two types of aging, and avoid performance redundancy or deficiency caused by excessive use of a certain type of anti-aging agent.

[0013] In some embodiments, the main antioxidant is preferably antioxidant 1010, the ultraviolet absorber is preferably UV-327, and the mass ratio of the two is 1:1.2-1:1.5; this specific combination and ratio can further improve the anti-aging synergistic effect, and compared with other anti-aging agent combinations, it can more efficiently resist aging erosion in complex environments.

[0014] In some embodiments, the auxiliary antioxidant is selected from phosphite antioxidants, and is preferably antioxidant 168; the auxiliary antioxidant can form a "free radical capture-hydrogen peroxide decomposition" synergistic system with the main antioxidant, further inhibit the thermal oxidation aging chain reaction, and improve the long-term thermal stability of the material.

[0015] In some embodiments, the grafting monomer is selected from maleic anhydride or maleic anhydride derivatives (such as maleic anhydride grafted polyethylene), preferably maleic anhydride, and the mass percentage is preferably 0.5%-1%; the grafting monomer can form a chemical bond between the nylon molecular chain and the surface of the functionalized nanocarrier through in-situ grafting reaction, improve the compatibility of the two, avoid delamination of the material after molding, and reasonable amount can avoid material embrittlement due to excessive amount.

[0016] In some embodiments, the preparation method of the anti-aging nylon modified material is as follows: first step, premixing, adding nylon base material, functionalized nanocarrier and auxiliary antioxidant into a high-speed mixer, mixing at a speed of 1500-2500 r / min and a temperature of 80-100℃ for 10-20 min to obtain a uniform premix; second step, melt blending-in-situ grafting, adding the premix into a twin-screw extruder, controlling the screw speed at 180-280 r / min and the temperature of each zone of the extruder at 220-270℃, injecting the grafting monomer into the head of the extruder through a metering pump, and then extruding and granulating after melt blending and in-situ grafting reaction to obtain the anti-aging nylon modified material.

[0017] In some embodiments, the application scenarios of the anti-aging nylon modified material are to prepare protective components (protective covers, light barriers) of elevator transmission systems, components (such as power battery housings and engine intake pipes) of new energy vehicles, accessories (such as bracket connectors and outdoor distribution box housings) of photovoltaic supports, or connectors (such as wiring terminals and sensor housings) of electronic and electrical appliances, by adjusting the injection molding temperature (230-250℃) to adapt to the molding requirements of different components.

[0018] After solving the basic technical problem by functionalized nanocarriers, the inventors found that three types of derived problems were caused by the introduction of the carriers, which needed to be solved through targeted derived characteristics: Insufficient synergistic effect of anti-aging agents: although the functionalized nanocarriers achieve the loading of double anti-aging agents, the proportion is not optimized, the main antioxidant is excessive, the light aging protection is insufficient, and the ultraviolet absorber is excessive, the heat and oxygen aging inhibition effect decreases. Therefore, the mass ratio of the main antioxidant 1010 to the ultraviolet absorber UV-327 is optimized to 1:1.2-1:1.5, which is verified by 20 groups of orthogonal experiments, can avoid the competition and consumption of anti-aging agents, and the synergistic efficiency is increased by 15% compared with the 1:1 ratio; Insufficient compatibility of the carrier and the nylon: the surface modification of the functionalized nanocarrier can only initially improve the compatibility, and no chemical bond is formed, the material is prone to delamination and the impact strength decreases. Therefore, the in-situ grafting process of the twin-screw extruder head is adopted, maleic anhydride is injected at 240-250℃, and a chemical bond is formed between the maleic anhydride and the molecular chain of the nylon and the amino group on the surface of the carrier, the interfacial bonding force is increased by 40%, and the impact strength is increased by 30% compared with the conventional blending process; Anti-aging agent high temperature decomposition: the anti-aging agent of the functionalized nano-carrier is easy to decompose in the extrusion high temperature zone, especially the decomposition rate of auxiliary antioxidant 168 is more than 20%. Therefore, the temperature of each zone of the extruder is controlled in the following way: the first zone is 220-230 DEG C, the second zone is 240-250 DEG C, the third zone is 250-260 DEG C, and the head is 240-250 DEG C, so that the decomposition rate of 168 is reduced to less than 5%, and the heat and oxygen aging protection effect retention rate is increased by 20%.

[0019] The present application has the following beneficial effects compared with the prior art: The present application breaks through the bottleneck of traditional nylon material aging resistance not comprehensive and poor long-acting by using self-made functionalized nano-carrier. The synergistic effect of the main antioxidant and the ultraviolet absorber can resist heat and oxygen aging and light aging at the same time. The slow-release design of the carrier can also reduce the volatilization of the anti-aging agent in processing and the migration in use, greatly prolonging the material protection life. At the same time, the nano-carrier can be uniformly dispersed in the nylon matrix after surface modification, avoiding the problem of mechanical property decline caused by traditional nano-particle agglomeration, and without the need for additional addition of a compatibilizer, reducing the production cost. In addition, through the optimization of the formula and process, the material can adapt to the differentiated scene needs of the protection components of the elevator transmission system, new energy vehicles, photovoltaic, electronic appliances and other new fields, expanding the application range of nylon materials, and the overall process can be realized based on the existing equipment, with high industrialization feasibility, and meeting the IPC classification requirements of the strategic emerging industry, providing support for the technical layout of enterprises in the new field. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0021] Example 1 Preparation of functionalized nano-carrier: Preparation of mesoporous silica nanospheres: take 100g of tetraethyl orthosilicate, add 500mL of ethanol-water mixture (ethanol to water volume ratio 3:1), stir uniformly, then add ammonia water to adjust pH to 9, stir at 30 DEG C for 8h; after the reaction is completed, centrifugal separation is carried out, the solid is collected and dried at 80 DEG C, then placed in a muffle furnace at 500 DEG C for 4h, to obtain mesoporous silica nanospheres with a particle size of 30nm and a pore size of 3nm.

[0022] Surface modification: take 50 g of the above mesoporous silica nanospheres, add 300 mL of ethanol, then add 3 g of silane coupling agent KH-550, stir at 60°C for 4 h; after the reaction is completed, centrifugal separation, collect the solid and dry, to get the surface of the modified mesoporous silica nanospheres grafted with amino groups.

[0023] Anti-aging agent loading: add the modified mesoporous silica nanospheres to 300 mL of acetone, then add 5 g of primary antioxidant 1010 and 5 g of ultraviolet absorber UV-326, stir at 50°C for 6 h; then remove the acetone by distillation under reduced pressure, dry the solid, to get the functionalized nanocarrier with a total anti-aging agent loading of 20%.

[0024] Preparation of anti-aging nylon modified material: Premixing: take 80% PA66 (relative viscosity 2.4), 10% functionalized nanocarrier, 0.5% auxiliary antioxidant 168, and 2% maleic anhydride by mass percentage, add to a high-speed mixer, mix at a speed of 1500 r / min and a temperature of 80°C for 20 min, to get the premix.

[0025] Melt blending-in situ grafting: add the premix to a twin-screw extruder, set the screw speed to 180 r / min, control the temperature of each zone of the extruder to 220-270°C; inject maleic anhydride at the head of the extruder through a metering pump, after melt blending and in-situ grafting reaction, extrude and pelletize, to get the anti-aging nylon modified material.

[0026] Example 2 Preparation of functionalized nanocarrier: Preparation of mesoporous silica nanospheres: take 100 g of tetraethyl orthosilicate, add 500 mL of ethanol-water mixture, stir uniformly, then add ammonia water to adjust the pH to 10, stir at 60°C for 4 h; after the reaction is completed, centrifugal separation, collect the solid and dry at 80°C, then place in a muffle furnace and calcine at 600°C for 2 h, to get mesoporous silica nanospheres with a particle size of 50 nm and a pore size of 5 nm.

[0027] Surface modification: take 50 g of the above mesoporous silica nanospheres, add 300 mL of ethanol, then add 5 g of silane coupling agent KH-560, stir at 90°C for 1 h; after the reaction is completed, centrifugal separation, collect the solid and dry, to get the modified mesoporous silica nanospheres grafted with epoxy groups on the surface.

[0028] Anti-aging agent loading: add the modified mesoporous silica nanospheres to 300 mL of acetone, then add 8 g of primary antioxidant 1010 and 10 g of ultraviolet absorber UV-327, stir at 70°C for 3 h; then remove the acetone by distillation under reduced pressure, dry the solid, to get the functionalized nanocarrier with a total anti-aging agent loading of 36%.

[0029] Preparation of anti-aging nylon modified material: Premixing: 90% PA66 (relative viscosity 2.8), 7% functionalized nano-carrier, 0.2% auxiliary antioxidant 168, and 0.8% maleic anhydride were weighed according to the mass percentage, added to a high-speed mixer, and mixed at a speed of 2200 r / min and a temperature of 90°C for 15 min to obtain a premix.

[0030] Melt blending-in situ grafting: the premix was added to a twin-screw extruder, the screw speed was set to 220 r / min, and the temperature of each zone of the extruder was controlled to be 230°C for zone 1, 240°C for zone 2, 250°C for zone 3, and 240°C for the die head. Maleic anhydride was injected into the die head of the extruder through a metering pump, and the grafting rate was controlled to be 1%. After melt blending and in-situ grafting, the product was extruded and granulated to obtain the anti-aging nylon modified material.

[0031] Example 3 Preparation of functionalized nano-carrier: Preparation of mesoporous carbon nanospheres: 100 g of sucrose was added to 500 mL of deionized water, stirred uniformly, and then citric acid was added to adjust the pH to 2. The mixture was stirred at 60°C for 4 h. After the reaction was completed, the solid was separated by centrifugation and dried at 120°C. Then it was placed in a muffle furnace at 600°C for 2 h to obtain mesoporous carbon nanospheres with a particle size of 80 nm and a pore size of 10 nm.

[0032] Surface modification: 50 g of the above mesoporous carbon nanospheres were added to 300 mL of ethanol, and then 5 g of silane coupling agent KH-560 was added. The mixture was stirred at 80°C for 2 h. After the reaction was completed, the solid was separated by centrifugation and dried to obtain modified mesoporous carbon nanospheres with epoxy groups grafted on the surface.

[0033] Anti-aging agent loading: The modified mesoporous carbon nanospheres were added to 300 mL of acetone, and then 9 g of primary antioxidant 1010 and 9 g of ultraviolet absorber UV-327 were added. The mixture was stirred at 60°C for 4 h. After that, the acetone was removed by distillation under reduced pressure, and the solid was dried to obtain functionalized nano-carriers with a total loading of anti-aging agents of 36%.

[0034] Preparation of anti-aging nylon modified material: Premixing: 85% PA6, 8% functionalized nano-carrier, 0.3% auxiliary antioxidant 168, and 1.7% maleic anhydride derivative (MAH-g-PE) were weighed according to the mass percentage, added to a high-speed mixer, and mixed at a speed of 2000 r / min and a temperature of 90°C for 12 min to obtain a premix.

[0035] Melt blending-in situ grafting: the premix was added into a twin-screw extruder, the screw rotation speed was set at 250 r / min, and the temperature of each zone of the extruder was controlled at 220 ℃ for zone 1, 230 ℃ for zone 2, 240 ℃ for zone 3, and 230 ℃ for the die head. Maleic anhydride derivative was injected into the die head of the extruder through a metering pump, and then the melt blending and in-situ grafting reaction were carried out to obtain the anti-aging nylon modified material after extrusion and granulation.

[0036] Comparative Example 1: no carrier (only free anti-aging agent) 80% PA66 (relative viscosity 2.4), 0.5% primary antioxidant 1010, 0.5% UV absorber UV-326, 0.5% auxiliary antioxidant 168, and 2% maleic anhydride were weighed according to the mass percentage, added into a high-speed mixer, and mixed at a rotation speed of 1500 r / min and a temperature of 80 ℃ for 20 min to obtain a premix.

[0037] 2. The premix was added into a twin-screw extruder, the screw rotation speed was set at 180 r / min, and the temperature of each zone of the extruder was controlled at 220-270 ℃. Maleic anhydride was injected into the die head of the extruder through a metering pump, and then the melt blending and in-situ grafting reaction were carried out to obtain the modified nylon material after extrusion and granulation.

[0038] Comparative Example 2: unmodified nanoparticles + free anti-aging agent 80% PA66 (relative viscosity 2.4), 10% unmodified silica nanospheres (particle size 30 nm), 0.5% primary antioxidant 1010, 0.5% UV absorber UV-326, 0.5% auxiliary antioxidant 168, and 2% maleic anhydride were weighed according to the mass percentage, added into a high-speed mixer, and mixed at a rotation speed of 1500 r / min and a temperature of 80 ℃ for 20 min to obtain a premix.

[0039] The premix was added into a twin-screw extruder, the screw rotation speed was set at 180 r / min, and the temperature of each zone of the extruder was controlled at 220-270 ℃. Maleic anhydride was injected into the die head of the extruder through a metering pump, and then the melt blending and in-situ grafting reaction were carried out to obtain the modified nylon material after extrusion and granulation.

[0040] Comparative Example 3: functionalized nanocarrier (without modification step) + free anti-aging agent Preparation of functionalized nanocarrier: Preparation of mesoporous silica nanospheres: same as step 1.1 in Example 1.

[0041] Anti-aging agent loading: 50 g of unmodified mesoporous silica nanospheres were directly taken into 300 mL of acetone, and then 5 g of primary antioxidant 1010 and 5 g of UV absorber UV-326 were added. The mixture was stirred at 50 ℃ for 6 h. Then the acetone was removed by distillation under reduced pressure, and the solid was dried to obtain the anti-aging agent-loaded nanocarrier (without surface modification).

[0042] Preparation of modified nylon material: same as step 2 in example 1.

[0043] Comparative example 4: functionalized nanocarriers + conventional blending (without in-situ grafting) Preparation of functionalized nanocarriers: same as step 1 in example 1.

[0044] Preparation of modified nylon material: According to the formulation of step 2.1 in example 1, maleic anhydride and other components were added into a high-speed mixer, and the premix was obtained under the same conditions.

[0045] The premix was added into a twin-screw extruder, and the screw speed was set to 180 r / min. The temperature of each zone of the extruder was controlled at 220-270°C. Direct extrusion granulation (without in-situ grafting) was performed to obtain the modified nylon material.

[0046] Comparative example 5: comparative example 2 + additional compatibilizer According to the mass percentage, 80% PA66 (relative viscosity 2.4), 10% unmodified silica nanospheres (particle size 30 nm), 0.5% primary antioxidant 1010, 0.5% ultraviolet absorber UV-326, 0.5% auxiliary antioxidant 168, 2% maleic anhydride, and 3% compatibilizer POE-g-MAH were weighed and added into a high-speed mixer. The premix was obtained by mixing at a speed of 1500 r / min and a temperature of 80°C for 20 min.

[0047] The premix was added into a twin-screw extruder, and the screw speed was set to 180 r / min. The temperature of each zone of the extruder was controlled at 220-270°C. Maleic anhydride was injected into the extruder head through a metering pump, and the modified nylon material was obtained after melt blending and in-situ grafting.

[0048] Comparative example 6: extreme ratio of anti-aging agents (1:2) Preparation of functionalized nanocarriers: Preparation of mesoporous silica nanospheres: 100 g of tetraethyl orthosilicate was added into 500 mL of ethanol-water mixture, and ammonia water was added to adjust the pH to 10. The mixture was stirred at 60°C for 4 h. After the reaction, the solid was separated by centrifugation and dried at 80°C. Then, the solid was calcined in a muffle furnace at 600°C for 2 h to obtain mesoporous silica nanospheres with a particle size of 50 nm and a pore size of 5 nm.

[0049] Surface modification: 50 g of the above mesoporous silica nanospheres were weighed, 300 mL of ethanol was added, and 5 g of silane coupling agent KH-560 was added. The mixture was stirred at 90°C for 1 h. After the reaction, the solid was separated by centrifugation and dried to obtain modified mesoporous silica nanospheres with grafted epoxy groups on the surface.

[0050] Antioxidant loading: The modified mesoporous silica nanospheres were added into 300 mL of acetone, followed by the addition of 8 g of primary antioxidant 1010 and 16 g of UV absorber UV-327 (mass ratio 1:2), and stirred at 70°C for 3 h; then the acetone was removed by distillation under reduced pressure, and the solid was dried to obtain the functionalized nanocarrier with a total antioxidant loading of 48%.

[0051] Preparation of modified nylon material: Premixing: 90% PA66 (relative viscosity 2.8), 7% functionalized nanocarrier, 0.2% auxiliary antioxidant 168, and 0.8% maleic anhydride were weighed according to the mass percentage, added into a high-speed mixer, and mixed at a speed of 2200 r / min and a temperature of 90°C for 15 min to obtain a premix.

[0052] Melt blending-in situ grafting: The premix was added into a twin-screw extruder, and the screw speed was set to 220 r / min. The temperatures of the extruder zones were controlled to be 230°C for zone 1, 240°C for zone 2, 250°C for zone 3, and 240°C for the die head. Maleic anhydride was injected into the extruder die head through a metering pump, and the grafting rate was controlled to be 1%. After melt blending and in-situ grafting, the product was extruded and granulated to obtain the modified nylon material.

[0053] Comparative Example 7: PA6 + unmodified mesoporous carbon carrier Preparation of functionalized nanocarrier: Preparation of mesoporous carbon nanospheres: 100 g of sucrose was added into 500 mL of deionized water, stirred uniformly, and then citric acid was added to adjust the pH to 2. The mixture was stirred at 60°C for 4 h. After the reaction was completed, the solid was separated by centrifugation and dried at 120°C. Then, the solid was calcined in a muffle furnace at 600°C for 2 h to obtain mesoporous carbon nanospheres with a particle size of 80 nm and a pore size of 10 nm.

[0054] Antioxidant loading: 50 g of the above unmodified mesoporous carbon nanospheres were directly added into 300 mL of acetone, followed by the addition of 9 g of primary antioxidant 1010 and 9 g of UV absorber UV-327. The mixture was stirred at 60°C for 4 h. After that, the acetone was removed by distillation under reduced pressure, and the solid was dried to obtain the unmodified mesoporous carbon carrier with a total antioxidant loading of 36%.

[0055] Preparation of modified nylon material: Premixing: 85% PA6, 8% unmodified mesoporous carbon carrier, 0.3% auxiliary antioxidant 168, and 1.7% maleic anhydride derivative (MAH-g-PE) were weighed according to the mass percentage, added into a high-speed mixer, and mixed at a speed of 2000 r / min and a temperature of 90°C for 12 min to obtain a premix.

[0056] Melt blending-in situ grafting: the premix was added into a twin-screw extruder, the screw rotation speed was set to 250 r / min, and the temperature of each zone of the extruder was controlled to be 220℃ for the first zone, 230℃ for the second zone, 240℃ for the third zone, and 230℃ for the die head; the maleic anhydride derivative was injected into the die head of the extruder through a metering pump, and after melt blending and in-situ grafting reaction, the modified nylon material was obtained by extrusion granulation.

[0057] Performance verification 1. Processed anti-aging agent retention rate test: the materials before and after extrusion granulation during the preparation of examples 1-3 and comparative examples 1-5 were taken respectively, the content of anti-aging agent (1010, UV-326 / UV-327) was determined by high performance liquid chromatography, and the retention rate (anti-aging agent content after granulation / anti-aging agent content before granulation x 100%) was calculated.

[0058] 2. Xenon lamp aging performance test: the materials prepared in each example were injection molded into standard tensile specimens, and according to GB / T16422.2-2014, 5000h aging test was carried out in a xenon lamp aging test chamber (irradiation intensity 0.71W / m 2 @340nm, black standard temperature 63℃, relative humidity 50%), and the tensile strength before and after aging was tested according to GB / T1040.2-2006, and the tensile strength retention rate (tensile strength after aging / tensile strength before aging x 100%) was calculated.

[0059] 3. Impact strength test: the materials prepared in each example were injection molded into standard impact specimens, and the notched impact strength was tested by using a simply supported beam impact testing machine according to GB / T1043.1-2008.

[0060] 4. Dispersion uniformity and delamination observation: the materials prepared in each example were sliced, and the dispersion of nanoparticles was observed by scanning electron microscope; at the same time, the materials were injection molded into a 100mm x 100mm x 2mm sample plate, which was placed at room temperature for 30 days, and whether delamination occurred was observed.

[0061] Performance results:

[0062] According to the performance verification data and the differences between the technical solutions of each example, it can be seen that example 1 adopts “basic mesoporous silica nanocarrier (particle size 30nm, pore size 3nm) + standard mixing-extrusion process”, realizes the loading and slow release of anti-aging agent through mesoporous carrier, the retention rate of processed anti-aging agent reaches 95%, the tensile strength retention rate after xenon lamp aging for 5000h is 80%, and the impact strength is 8.0kJ / m 2, the nanoparticles were uniformly dispersed, and the core problem of traditional nylon aging resistance, such as incomplete protection and poor long-term effect, was solved; in Example 2, the size of the mesoporous carrier (particle size 50 nm, pore size 5 nm), the proportion of the anti-aging agent (mass ratio of 1010 to UV-327 1:1.25), and the extrusion partition temperature control process (one zone 230°C, two zones 240°C, three zones 250°C, and the die head 240°C) were optimized, and the maleic anhydride grafting rate was controlled at 1%, which further improved the performance compared with Example 1, the processing anti-aging agent retention rate increased to 97%, the tensile strength retention rate after aging reached 85%, and the impact strength was 8.5kJ / m 2 , and the material had no yellowing and no delamination, which proved that the synergistic effect of carrier size optimization, anti-aging agent proportion adjustment, and partition temperature control process could further optimize the aging resistance and mechanical properties on the basis of solving the core problem; in Example 3, mesoporous carbon nanospheres (particle size 80 nm, pore size 10 nm) were selected as the carrier, and maleic anhydride derivatives (MAH-g-PE) were used, and the extrusion temperature suitable for PA6 substrate (one zone 220°C, two zones 230°C, three zones 240°C, and the die head 230°C) was used, the processing anti-aging agent retention rate was 96%, the tensile strength retention rate after aging was 82%, and the impact strength was 8.3kJ / m 2 , which verified the adaptability of different mesoporous carrier materials and substrates, and expanded the application range of the scheme.

[0063] Comparative Example 1 did not use mesoporous carriers, but directly added free anti-aging agents, and the processing anti-aging agent retention rate was only 68%, the tensile strength retention rate after aging was 52%, which highlighted the key role of mesoporous carriers in improving the long-term effect of anti-aging; Comparative Example 2 used unmodified silica nanospheres with free anti-aging agents, and the nanoparticles were severely agglomerated, and the impact strength was only 5.8kJ / m 2 , which proved the necessity of surface modification of the carrier; Comparative Example 3 omitted the surface modification step of the mesoporous carrier, although the anti-aging agent was loaded, there was still some agglomeration, the impact strength was 6.2kJ / m 2 , and the tensile strength retention rate after aging was 55%, which further confirmed the influence of surface modification on the dispersion of the carrier and the anti-aging effect; Comparative Example 4 did not use the die in-situ grafting process, and maleic anhydride was mixed and extruded with other components, the material had slight delamination, and the impact strength was 6.5kJ / m 2 , which showed the importance of in-situ grafting in improving the compatibility of the carrier and the nylon matrix; Comparative Example 5 additionally added a compatibilizer POE-g-MAH based on Comparative Example 2, and there was still a small amount of agglomeration, the impact strength was 6.0kJ / m 2 , and the tensile strength retention rate after aging was 53%, which proved that even if a compatibilizer was added, it could not replace the synergistic effect of the "mesoporous carrier modification + in-situ grafting" of the present scheme.

[0064] To sum up, the application can effectively solve the performance short board of the traditional modified nylon through the synergistic cooperation of the mesoporous carrier design, the anti-aging agent loading and the proportion optimization, the in-situ grafting and the partition temperature control process, and the technical means adjustment and performance improvement of each embodiment form a clear corresponding relationship, and the technical effect is significantly better than the comparative examples which lack core technical means or adopt traditional scheme, and the scheme innovation and practicality are clear.

[0065] The above merely describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An age resistant nylon modified material characterized by, The application relates to a kind of anti-aging nylon modified materials, which is prepared from the following components by mass percentage: nylon base material 80%-98%, functionalized nano-carrier 1%-10%, auxiliary antioxidant 0.05%-0.5%, grafting monomer 0.1%-2%; the functionalized nano-carrier is a composite particle of mesoporous nano-sphere loaded anti-aging agent, the particle size of the mesoporous nano-sphere is 30-100 nm, the pore size is 3-15 nm, and the total loading amount of the anti-aging agent is 20%-50% of the mass of the mesoporous nano-sphere; the anti-aging agent comprises a main antioxidant and an ultraviolet absorber; the preparation steps of the functionalized nano-carrier include: (1) mesoporous nano-sphere preparation: tetraethyl orthosilicate or sucrose is added to an ethanol-water mixed solution, ammonia water is added to adjust the pH to 9-10, stirring is carried out at 30-60 DEG C for 4-8 h, and after centrifugal drying, calcination is carried out at 500-600 DEG C for 2-4 h; (2) surface modification: the mesoporous nano-sphere is reacted with a silane coupling agent in an ethanol solution, the amount of the silane coupling agent is 3%-10% of the mass of the mesoporous nano-sphere, the reaction temperature is 60-90 DEG C, and the reaction time is 1-4 h; (3) anti-aging agent loading: the modified mesoporous nano-sphere is mixed with the anti-aging agent in an acetone solution, the temperature is 50-70 DEG C, and the time is 3-6 h.

2. The age resistant nylon modified material of claim 1, wherein, The mesoporous nano-sphere is a mesoporous silica nano-sphere or a mesoporous carbon nano-sphere, the particle size of the mesoporous nano-sphere is 50-80 nm, and the pore size is 5-10 nm.

3. The age resistant nylon modified material of claim 1, wherein, The mass ratio of the main antioxidant to the ultraviolet absorber in the anti-aging agent is 1:(1-2), the main antioxidant is a hindered phenolic antioxidant, and the ultraviolet absorber is a benzotriazole or a benzophenone ultraviolet absorber.

4. The age resistant nylon modified material of claim 3, wherein, The main antioxidant is antioxidant 1010, the ultraviolet absorber is ultraviolet absorber UV-327, and the mass ratio of the main antioxidant to the ultraviolet absorber is 1:(1.2-1.5).

5. The age resistant nylon modified material of claim 1, wherein, The nylon base material is PA6 or PA66, the relative viscosity of the PA66 is 2.4-2.8, the auxiliary antioxidant is a phosphite antioxidant, and the grafting monomer is maleic anhydride or a maleic anhydride derivative.

6. The age resistant nylon modified material of claim 5, wherein, The auxiliary antioxidant is antioxidant 168, and the grafting monomer is maleic anhydride, and the mass percentage of the grafting monomer is 0.5%-1%.

7. A method of preparing the weatherable nylon modified material according to any one of claims 1 to 6, characterized in that, The application further discloses a preparation method of the anti-aging nylon modified material, which comprises the following steps: (1) pre-mixing: the nylon base material, the functionalized nano-carrier, and the auxiliary antioxidant are added into a high-speed mixer, the rotation speed is 1500-2500 r / min, the temperature is 80-100 DEG C, and the mixing time is 10-20 min to obtain a premix; (2) melt blending-in situ grafting: the premix is added into a double-screw extruder, the screw rotation speed is 180-280 r / min, the temperature of each zone is 220-270 DEG C, a metering pump is used to inject the grafting monomer into the head of the extruder, and extrusion and granulation are carried out to obtain the anti-aging nylon modified material.

8. The preparation method according to claim 7, characterized in that, In step (1), the rotation speed of the high-speed mixer is 1800-2200 r / min, and the mixing time is 12-15 min.

9. The preparation method according to claim 7, characterized in that, The temperature of each zone of the double screw extruder in step (2) is controlled in sections, the temperature of the first zone is 220-230 DEG C, the temperature of the second zone is 240-250 DEG C, the temperature of the third zone is 250-260 DEG C, and the temperature of the die head is 240-250 DEG C; the injection rate of the grafting monomer is matched with the extrusion rate, so as to ensure that the grafting rate is 0.5%-1.5%.

10. Use of the age resistant nylon modified material according to any one of claims 1 to 6, characterized in that The anti-aging nylon modified material is prepared into a component by injection molding, and the component comprises an elevator transmission system protective cover, a light shielding plate, a new energy automobile power battery shell, an engine air inlet pipe, a photovoltaic support accessory or an electronic and electrical connector.

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