A method for producing a high-strength wear-resistant nylon 66 material

Abstract

The application belongs to the field of high polymer materials, and discloses a method for preparing high-strength wear-resistant nylon 66 material, wherein a silane coupling agent and a cross-linking promoter are coated on the surface of nano silicon dioxide, and the stability of the coating structure is improved through gamma ray irradiation, so that the mechanical properties and wear resistance of the nylon 66 can be improved after the nylon 66 is added, and meanwhile, the nylon 66 of the application can still maintain good rigidity and wear resistance and has excellent comprehensive performance after long-term use.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a method for preparing high-strength, wear-resistant nylon 66 materials. Background Technology

[0002] Nylon possesses high mechanical strength and a high softening point, making it a major type of engineering plastic. However, nylon also suffers from high water absorption, poor dimensional stability, and poor low-temperature toughness, resulting in poor wear resistance. In the automotive industry, nylon 66 is used to manufacture bearings, gears, and other components. These parts are subjected to significant friction and wear during operation, requiring excellent wear resistance to ensure the normal operation and lifespan of the vehicle.

[0003] Conventional abrasion-resistant modification of nylon 66 involves adding inorganic molybdenum disulfide, graphite, talc, etc. While this improves the abrasion resistance of the material, it significantly reduces the mechanical properties of nylon 66.

[0004] Therefore, the high-strength and wear-resistant modification of Nylon 66 is of great significance to promoting the development of emerging industries in my country. Summary of the Invention

[0005] To address the above issues, this invention provides a method for preparing high-strength, wear-resistant nylon 66 materials. This method involves coating the surface of nano-silica with a silane coupling agent and a crosslinking accelerator, and then improving the stability of the coating structure through gamma ray irradiation. Adding these to nylon 66 can enhance its mechanical properties and wear resistance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing high-strength, wear-resistant nylon 66 material includes the following steps:

[0008] (1) Dissolve the silane coupling agent and crosslinking accelerator in dimethylformamide to form a solution, wherein the weight ratio of the silane coupling agent, crosslinking accelerator and dimethylformamide is 1:(0.001~0.05):(50~500).

[0009] (2) Add 1% to 50% of the mass of dimethylformamide to the above solution of nano-silica, stir at high speed of 10-15 rpm for 30 min to 120 min, and then treat with ultrasound for 10 min to 60 min to obtain a suspension of nano-silica;

[0010] (3) Add water to the suspension obtained in step (2), stir for 8-12 minutes, let stand and separate into layers, remove the liquid phase layer; dry the remaining material and treat it with gamma ray irradiation; the weight ratio of the suspension to water is 1: (5~100); the irradiation absorption dose during irradiation treatment is 1kGy~500kGy;

[0011] (4) The material after irradiation treatment in step (3) is crushed into powder with an average particle size of less than 5 micrometers to obtain nano-silica powder containing silane coupling agent and crosslinking promoter.

[0012] (5) The powder obtained in step (4) is mixed with nylon 66, lubricant and antioxidant and extruded and granulated by an extruder to obtain high-strength wear-resistant nylon 66 material; the weight ratio of nylon 66, powder, toughening agent, nucleating agent, lubricant and antioxidant is 100: (1~10): (0.2~0.7): (0.2~0.7).

[0013] Preferably, in step (2), the amount of nano-silica added is 1% to 20% of the mass of dimethylformamide.

[0014] Preferably, in step (1), the silane coupling agent is one or a mixture of two or more of KH550, KH560 and KH570.

[0015] More preferably, the silane coupling agent is a mixture of KH550 and KH570 in equal mass ratios.

[0016] Preferably, in step (1), the crosslinking promoter is one or a mixture of two or more of triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, bis-trimethylolpropane tetraacrylate and bis-pentaerythritol hexaacrylate.

[0017] Preferably, in step (5), the lubricant is one or a mixture of two or more of silicone, EBS, PE wax, and PETS.

[0018] Preferably, in step (5), the antioxidant is one or a mixture of two or more of 168, 1098, 1076, 1010, H11, and S9228.

[0019] In this invention, the agglomeration of nano-silica was solved by mixing coupling agents KH-550 and KH-570 in equal proportions and stirring at high speed. This improved the dispersibility of nano-silica in the coupling agent and crosslinking accelerator media, as well as the adhesion of the silane coupling agent to the surface of nano-silica, thus increasing the surface energy of nano-silica. Furthermore, gamma ray irradiation crosslinking made it easier for the active groups on the surface of nano-silica to transition from the ground state to the excited state, thereby increasing the coating stability of nano-silica.

[0020] Specifically, in this invention, the irradiation absorption dose during irradiation treatment is 1 kGy to 500 kGy, preferably 50-80 kGy. This way, the higher the gamma ray irradiation intensity, the easier it is for the active groups on the surface of nano-silica to transition from the ground state to the excited state, thus increasing the coating stability of nano-silica. However, if the irradiation intensity is too high, the performance of the coating material will be reduced. Therefore, this invention selects 1 kGy to 500 kGy, preferably 50-80 kGy.

[0021] The main purpose of this invention in selecting coupling agents is to address the agglomeration performance of nano-silica. Compared to using KH550 or KH570 alone, mixing KH550 and KH570 in equal mass ratios provides both the highly hydrophilic aminopropyl group and the lipophilic methacryloyloxy group, ensuring the best coating effect of nano-silica under the same stirring treatment. This effectively solves the agglomeration problem of nano-silica, improves the dispersibility of nano-silica in the coupling agent and crosslinking accelerator media, enhances the adhesion of the silane coupling agent to the surface of nano-silica, and increases the surface energy of nano-silica.

[0022] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0023] This invention provides a novel method for preparing high-strength, wear-resistant nylon 66 material. By coating the surface of nano-silica with a silane coupling agent and a crosslinking accelerator, and improving the stability of the coating structure through gamma ray irradiation, the mechanical properties and wear resistance of nylon 66 can be improved. At the same time, after long-term use, the nylon 66 of this invention can still maintain good rigidity and wear resistance, exhibiting excellent overall performance. Detailed Implementation

[0024] To illustrate the effects of the present invention, specific embodiments are described below for further explanation.

[0025] Example 1

[0026] This embodiment of a method for preparing high-strength, wear-resistant nylon 66 material includes the following steps:

[0027] (1) Weigh 10g of silane coupling agent and 0.5g of crosslinking accelerator and dissolve them in 5000g of dimethylformamide solvent to form a solution; in this example, the coupling agent is KH-550 coupling agent and the crosslinking accelerator is TAIC (tracene propyl isocyanurate).

[0028] (2) Add 50g of nano silica to the above solution, stir at high speed of 15 rpm for 30min, and then sonicate for 60min to obtain a suspension of nano silica.

[0029] (3) Add deionized water to the suspension at a weight ratio of 1:5 for the suspension and water, stir for 10 min, let stand and separate into layers, remove the liquid phase separation, dry the obtained residue, treat with gamma rays, and the irradiation absorbed dose is 50 kGy.

[0030] (4) The irradiated material is crushed into powder with an average particle size of less than 5 micrometers to obtain nano-silica powder coated with silane coupling agent and crosslinking promoter.

[0031] (5) Weigh 1000g of nylon 66, 50g of nano-silica powder coated with silane coupling agent and crosslinking accelerator, 5g of lubricant and 5g of antioxidant and mix them; granulate the mixture on an extruder at an extrusion temperature of 250~280℃, wherein the temperature is 250℃ in zone 1, 280℃ in zone 2, 280℃ in zone 3, 270℃ in zone 4, 270℃ in zone 5, 260℃ in zone 6, 260℃ in zone 7, 250℃ in zone 8, 255℃ in zone 9, 260℃ in zone 10 and 280℃ in the die head, to obtain high-strength and wear-resistant nylon 66 material.

[0032] In this embodiment, the lubricant is PETS (pentaerythritol stearate), and the antioxidant is a mixture of 168 and 1098 antioxidants in equal proportions.

[0033] Example 2

[0034] The method for preparing high-strength wear-resistant nylon 66 material in this embodiment is the same as in embodiment 1, except that the coupling agent in step (1) is silane coupling agent KH-570.

[0035] Example 3

[0036] The method for preparing high-strength wear-resistant nylon 66 material in this embodiment is the same as in embodiment 1, except that the coupling agent in step (1) is a mixture of silane coupling agents KH-550 and KH-570 in equal proportion.

[0037] Example 4

[0038] This embodiment of a method for preparing high-strength, wear-resistant nylon 66 material includes the following steps:

[0039] (1) Weigh 10g of silane coupling agent and 0.5g of crosslinking accelerator and dissolve them in 5000g of dimethylformamide solvent to form a solution; In this embodiment, the silane coupling agent is KH-570 and the crosslinking accelerator is TAIC (tracelyl isocyanurate);

[0040] (2) Add 50g of nano silica to the above solution, stir at high speed of 10 rpm for 120min, and then sonicate for 10min to obtain a suspension of nano silica.

[0041] (3) Add deionized water to the suspension at a weight ratio of 1:20 for the suspension and water, stir for 10 min, let stand and separate into layers, remove the liquid phase separation, dry the obtained residue, treat with gamma rays, and the irradiation absorbed dose is 100 kGy.

[0042] (4) The irradiated material is crushed into powder with an average particle size of less than 5 micrometers to obtain nano-silica powder coated with silane coupling agent and crosslinking promoter.

[0043] (5) Weigh 1000g of nylon 66, 20g of nano-silica powder coated with silane coupling agent and crosslinking accelerator, 2g of lubricant and 2g of antioxidant and mix them; granulate the mixture on an extruder at an extrusion temperature of 250~280℃, wherein the temperature is 250℃ in zone 1, 280℃ in zone 2, 280℃ in zone 3, 270℃ in zone 4, 270℃ in zone 5, 260℃ in zone 6, 260℃ in zone 7, 250℃ in zone 8, 255℃ in zone 9, 260℃ in zone 10 and 280℃ in the die head, to obtain high-strength and wear-resistant nylon 66 material.

[0044] In this embodiment, the lubricant is PETS (pentaerythritol stearate), and the antioxidant is a mixture of 168 and 1098 antioxidants in equal proportions.

[0045] Example 5

[0046] This embodiment of a method for preparing high-strength, wear-resistant nylon 66 material includes the following steps:

[0047] (1) Weigh 100g of silane coupling agent and 0.1g of crosslinking accelerator and dissolve them in 5000g of dimethylformamide solvent to form a solution; In this embodiment, the silane coupling agent is a mixture of KH550 and KH570 in equal mass ratio, and the crosslinking accelerator is AIC (tracene propyl isocyanurate).

[0048] (2) Add 80g of nano silica to the above solution, stir at high speed of 15 rpm for 30min, and then sonicate for 60min to obtain a suspension of nano silica.

[0049] (3) Add deionized water to the suspension at a weight ratio of 1:80 for the suspension and water, stir for 10 min, let stand and separate into layers, remove the liquid phase separation, dry the obtained residue, treat with gamma rays, and the irradiation absorbed dose is 80 kGy.

[0050] (4) The irradiated material is crushed into powder with an average particle size of less than 5 micrometers to obtain nano-silica powder coated with silane coupling agent and crosslinking promoter.

[0051] (5) Weigh 1000g of nylon 66, 100g of nano-silica powder coated with silane coupling agent and crosslinking accelerator, 7g of lubricant, and 7g of antioxidant and mix them; granulate the resulting mixture on an extruder at an extrusion temperature of 250~280℃, wherein the temperatures are as follows: Zone 1 250℃, Zone 2 280℃, Zone 3 280℃, Zone 4 270℃, Zone 5 270℃, Zone 6 260℃, Zone 7 260℃, Zone 8 250℃, Zone 9 255℃, Zone 10 260℃, and die head temperature 280℃ to obtain high-strength and wear-resistant nylon 66 material. In this embodiment, the lubricant is PETS (pentaerythritol stearate), and the antioxidant is a mixture of 168 and 1098 antioxidants in equal proportions.

[0052] Example 6

[0053] This embodiment is the same as embodiment 3, except that in step (1), the amount of nano-silica used is 750g.

[0054] Example 7

[0055] This embodiment is the same as embodiment 3, except that in step (1), the amount of nano-silica used is 1000g.

[0056] Example 8

[0057] This embodiment is the same as embodiment 3, except that in step (1), the amount of nano-silica used is 2500g.

[0058] Example 9

[0059] This embodiment is the same as embodiment 3, except that in step (2), the irradiation absorbed dose is 100kGy.

[0060] Example 10

[0061] This embodiment is the same as embodiment 3, except that in step (2), the irradiation absorbed dose is 500 kGy.

[0062] Performance testing:

[0063] Standard specimens of the high-strength wear-resistant nylon 66 materials prepared in Examples 1-10 were made according to the standard injection molding process. After equilibration at 23°C and 50% humidity for 24 hours, and drying and annealing at 80°C for 2 hours, mechanical properties were tested. The results are shown in Table 1.

[0064] Table 1 Experimental Data

[0065] Test content Tensile strength Elongation at break Bending strength Notched impact strength coefficient of friction PA66 raw material 80 12 115 5 0.025 Example 1 82 15 115 4 0.018 Example 2 80 18 118 5.2 0.015 Example 3 85 70.6 120 5.8 0.011 Example 4 83 17 117 5.0 0.016 Example 5 84 68 118 5.6 0.012 Example 6 79 10 120 5.2 0.015 Example 7 75 8 118 4.5 0.014 Example 8 70 5 117 4 0.013 Example 9 82 50 115 5 0.012 Example 10 80 43 118 4 0.012

[0066] As can be seen from Table 1, the coupling agent is a mixture of silane coupling agents KH-550 and KH-570 in equal proportions, i.e.

[0067] In Example 3, the material exhibited the best performance across all parameters: tensile strength of 85 MPa, elongation at break of 70.6%, flexural strength of 120 MPa, flexural modulus of 2400 MPa, and notched impact strength of 5.8 KJ / M2.

[0068] The above embodiments are only used to illustrate the detailed method of the present invention, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvement to the method of the present invention, equivalent substitution of raw materials for the product, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing high-strength, wear-resistant nylon 66 material, characterized in that, Includes the following steps: (1) Dissolve the silane coupling agent and crosslinking accelerator in dimethylformamide to form a solution, wherein the weight ratio of the silane coupling agent, crosslinking accelerator and dimethylformamide is 1:(0.001 ~ 0.05):(50 ~ 500); the silane coupling agent is a mixture of KH550 and KH570 in equal mass ratio; (2) Add 1% to 20% of the mass of dimethylformamide to the above solution, stir at 10 to 15 rpm for 30 min to 120 min, and then sonicate for 10 min to 60 min to obtain a suspension of nano-silica. (3) Add water to the suspension obtained in step (2), stir for 8 to 12 minutes, let stand and separate into layers, remove the liquid phase layer; dry the remaining material and treat it with gamma irradiation; the weight ratio of the suspension to water is 1: (5 to 100); the irradiation absorbed dose during irradiation treatment is 50 kGy to 80 kGy; (4) The material after irradiation treatment in step (3) is crushed into powder with an average particle size of less than 5 micrometers to obtain nano-silica powder containing silane coupling agent and crosslinking promoter. (5) The powder obtained in step (4) is mixed with nylon 66, lubricant and antioxidant and extruded and granulated by an extruder to obtain high-strength wear-resistant nylon 66 material; The weight ratio of the nylon 66, powder, lubricant, and antioxidant is 100:(1~10):(0.2~0.7):(0.2~0.7).

2. The method for preparing high-strength, wear-resistant nylon 66 material according to claim 1, characterized in that, In step (1), the crosslinking promoter is one or a mixture of two or more of the following: triallyl isocyanurate, triallyl cyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, bis-trimethylolpropane tetraacrylate and bis-pentaerythritol hexaacrylate.

3. The method for preparing high-strength, wear-resistant nylon 66 material according to claim 1, characterized in that, In step (5), the lubricant is one or a mixture of two or more of silicone, EBS, PE wax, and PETS.

4. The method for preparing high-strength, wear-resistant nylon 66 material according to claim 1, characterized in that, In step (5), the antioxidant is one or a mixture of two or more of 168, 1098, 1076, 1010, H11, and S9228.