A heat- and corrosion-resistant modified PA material and its preparation method

Abstract

This invention discloses a heat-resistant and corrosion-resistant modified PA material and its preparation method, relating to the field of polymer materials. The method includes the following steps: premixing modified PA resin, PA6 resin, glass fiber, filler, stabilizer, lubricant, and antioxidant in a mixer; then feeding the premixed material into a twin-screw extruder through the main feed port; and extruding and granulating to obtain a heat-resistant and corrosion-resistant modified PA material. This invention achieves a comprehensive improvement in the heat resistance and corrosion resistance of the material by introducing high-bond-energy, hydrophobic, and inert PDMS segments into the resin chain ends, combined with glass fiber reinforcement and a reasonable additive system.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to a heat-resistant and corrosion-resistant modified PA material and its preparation method. Background Technology

[0002] Nylon (polyamide, abbreviated as PA), as one of the five major general-purpose engineering plastics, is widely used in the automotive, electronics, and aerospace industries due to its excellent mechanical properties, wear resistance, chemical corrosion resistance, and electrical insulation. The amide bonds (-CONH-) in its molecular chain endow the material with high strength and toughness. In the automotive field, nylon is often used to manufacture engine peripheral parts, piping systems, connectors, and other components that need to withstand high temperatures and chemical corrosion. However, nylon has poor stability in strong acid or alkali environments, so special consideration is required in certain applications.

[0003] To improve the performance of nylon, existing technologies mainly employ two approaches: physical blending modification and copolymerization modification. However, these methods still have significant drawbacks. Physical blending modification increases mechanical strength by adding reinforcing fibers or inorganic fillers, but due to poor interfacial compatibility, it easily leads to uneven dispersion and cannot fundamentally improve the heat resistance and corrosion resistance of the molecular chain. Copolymerization modification synthesizes semi-aromatic nylon by introducing aromatic monomers. Although it can reduce water absorption and improve heat resistance, it requires complex processes to control the copolymerization ratio to balance the melting point and decomposition temperature. Furthermore, copolymerization modification cannot end the active end groups (-NH2 / -COOH) of the molecular chain, which can still cause chain degradation in high-temperature, strong acid, and strong alkali environments.

[0004] Existing technologies cannot simultaneously block thermal oxidation and acid-base degradation, leading to accelerated performance degradation of materials in long-term high-temperature corrosive environments. Therefore, it is necessary to design a modified nylon material to solve the problem of chain-end degradation of nylon materials in high-temperature and corrosive environments. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a heat-resistant and corrosion-resistant modified PA material and its preparation method.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A heat-resistant and corrosion-resistant modified PA material, comprising the following components by weight: 5-10 parts modified PA resin, 10-30 parts PA6 resin, 10-20 parts glass fiber, 1-3 parts filler, 5-10 parts stabilizer, 1-2 parts lubricant, and 0.1-1 parts antioxidant.

[0008] Furthermore, the preparation method of the modified PA resin is as follows:

[0009] (1) Mix the organosilicon intermediate and epoxy linker, add catalyst and solvent, and react under nitrogen protection for 4-8 h to obtain EPO-PDMS;

[0010] (2) Dissolve EPO-PDMS in N-methylpyrrolidone, add acid anhydride monomer, and react under nitrogen protection for 2-6 hours to obtain a functional end-capping agent;

[0011] (3) The functional end-capping agent, lauric anhydride, organic titanate and PA resin are melt-blended and extruded to obtain modified PA resin.

[0012] Furthermore, in step (1), the organosilicon intermediate is bis(3-aminopropyl)-terminated polydimethylsiloxane; and the molecular weight is 600-2000.

[0013] Furthermore, in step (1), the epoxy linker is polyethylene glycol diglycidyl ether.

[0014] Furthermore, in step (1), the molar ratio of the organosilicon intermediate to the epoxy linker is 1:2-2.2; the amount of catalyst used is 0.3-0.7% of the total mass of the organosilicon intermediate and the epoxy linker.

[0015] Furthermore, the catalyst in step (1) is one of triethylamine and boron trifluoride.

[0016] Furthermore, in step (1), the solvent is toluene; the amount of solvent used is 1-3 times the total volume of the organosilicon intermediate and the epoxy linker.

[0017] Furthermore, in step (2), the anhydride monomer is one of cis-1,2,3,6-tetrahydrophthalic anhydride and hexahydrophthalic anhydride.

[0018] Furthermore, in step (2), the molar ratio of EPO-PDMS to acid anhydride monomer is 1:1-1.1; the volume ratio of EPO-PDMS to N-methylpyrrolidone is 1:1-3.

[0019] Furthermore, in step (3), the PA resin is either PA6 resin or PA66 resin.

[0020] Furthermore, in step (3), the mass ratio of functional capping agent, lauric anhydride, organic titanate, and PA resin is 1-2:0.5-1:0.05-0.2:100.

[0021] Furthermore, in step (3), the organic titanate is tetraisopropyl titanate.

[0022] Furthermore, the process requirements for the melt blending stage in step (3) are as follows: temperature range of 230-250℃; residence time of 5-15min; screw speed of 60-120rpm.

[0023] It should be noted that: the amino group of bis(3-aminopropyl)-terminated polydimethylsiloxane (PDMS) undergoes a ring-opening reaction with the epoxy group of polyethylene glycol diglycidyl ether (PEGDE) to form an epoxy-terminated PDMS chain; the epoxy group of EPO-PDMS reacts with cis-1,2,3,6-tetrahydrophthalic anhydride to generate a carboxyl-containing PDMS derivative, which serves as a functional end-capping agent for PA resin; the carboxyl group (-COOH) can undergo an amidation reaction with the amino group (-NH2) at the PA chain end, thereby effectively end-capping the PA molecular chain.

[0024] Furthermore, the filler is one or more of nano-calcium carbonate, mica powder, and boron nitride.

[0025] Furthermore, the stabilizer is one of carbodiimide and phosphite.

[0026] Furthermore, the lubricant is one of solid paraffin, stearamide, or fatty acid salt.

[0027] Furthermore, the antioxidant is one of antioxidants 1010 and 1076.

[0028] A method for preparing a heat-resistant and corrosion-resistant modified PA material includes the following steps: adding modified PA resin, PA6 resin, glass fiber, filler, stabilizer, lubricant and antioxidant into a mixing mixer for premixing, then adding the premixed material from the main feed port into a twin-screw extruder, extruding and cooling with water to granulate, thereby obtaining a heat-resistant and corrosion-resistant modified PA material.

[0029] The beneficial effects of this invention are:

[0030] (1) An important pathway of PA resin thermal degradation is the oxidation of terminal amino groups and the chain pyrolysis initiated by them. End-capping greatly reduces the number of these terminal amino groups that are prone to thermal oxidation, significantly improving the heat distortion temperature and long-term thermal aging resistance of the material. After end-capping, the PA molecular chain end groups become chemically inert amide bonds and PDMS segments, which significantly reduce the material's sensitivity to corrosive media such as water, acid, and alkali.

[0031] (2) Lauric anhydride, as an auxiliary end-capping agent, further consumes the residual PA terminal amino group; its long-chain alkyl group can provide additional lubricity and hydrophobicity; organic titanate, as a highly efficient catalyst, strongly promotes the amidation reaction (reaction of carboxyl group and amino group), ensuring the efficient and rapid reaction of functional end-capping agent with PA terminal group, and achieving full end-capping effect.

[0032] (3) Glass fiber effectively resists high temperature deformation by constructing a rigid skeleton; boron nitride / mica filler significantly improves thermal conductivity (prevents local overheating) and enhances the barrier to corrosive media; stabilizer can capture hydrolytic carboxyl groups and effectively inhibit acid catalytic degradation process; at the same time, it quenches free radicals and blocks the occurrence of oxidation chain reaction. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The sources of each raw material in the embodiments and comparative examples of this invention are as follows: PA6 resin (polyamide-6, 98%, Henan Zhuofan Chemical Co., Ltd.), glass fiber (AR, Shanghai Puzhen Biotechnology Co., Ltd.), mica powder (5μm, Forsman Technology (Beijing) Co., Ltd.), nano hexagonal boron nitride (100nm, 99.9%, Zhejiang Yamei Nanotechnology Co., Ltd.), N,N-dicyclohexylcarbodiimide (99%, Nanjing Delu Pharmaceutical Co., Ltd.), solid paraffin (99%, Tenghong (Shandong) New Materials Co., Ltd.), antioxidant 1076 and antioxidant 1010 (98%, Qingdao Zhenguang Functional Materials Technology Co., Ltd.), phosphite (98%, Shaanxi Didu New Materials Co., Ltd.), stearamide (99%, Wuhan) Fuxin Chemical Co., Ltd.), bis(3-aminopropyl)-terminated polydimethylsiloxane (MW1000, Weihai Miaochuan Biotechnology Co., Ltd.), polyethylene glycol diglycidyl ether (99%, Suzhou Senfida Chemical Co., Ltd.), triethylamine (99%, Jiangsu Runfeng Synthetic Technology Co., Ltd.), N-methylpyrrolidone (99%, Jiangsu Runfeng Synthetic Technology Co., Ltd.), cis-1,2,3,6-tetrahydrophthalic anhydride (98%, Shanghai Dingfen Chemical Technology Co., Ltd.), lauric anhydride (98%, Shanghai Maclean Biochemical Technology Co., Ltd.), tetraisopropyl titanate (≥99%, Shanghai Tongyuan Chemical Co., Ltd.), 1,2-epoxy-9-decene (96%, Sigma-Aldrich (Shanghai) Trading Co., Ltd.).

[0035] Example 1

[0036] A method for preparing a heat-resistant and corrosion-resistant modified PA material includes the following steps: 5 parts by weight of modified PA resin, 10 parts by weight of PA6 resin, 10 parts by weight of glass fiber, 1 part by weight of filler (mica powder and nano-hexagonal boron nitride in a mass ratio of 1:1), 5 parts by weight of N,N-dicyclohexylcarbodiimide, 1 part by weight of solid paraffin, and 0.1 parts by weight of antioxidant 1010 are added to a mixer and premixed for 5 minutes. Then, the premix is ​​fed into a twin-screw extruder through the main feed port and extruded at a melting temperature of 230°C. The screw extruder speed is 350 rpm, and the material is cooled with water at a temperature of 20°C. Granulation is performed with a particle size of 3 mm, and drying is carried out at 80°C for 4 hours to obtain a heat-resistant and corrosion-resistant modified PA material.

[0037] The preparation method of modified PA resin is as follows:

[0038] (1) Bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether were mixed, and triethylamine and toluene were added. The mixture was reacted at 60°C for 4 h under nitrogen protection to obtain EPO-PDMS.

[0039] The molar ratio of bis(3-aminopropyl)-terminated polydimethylsiloxane to polyethylene glycol diglycidyl ether is 1:2; the amount of triethylamine used is 0.3% of the total mass of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether; and the amount of toluene used is twice the total volume of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether.

[0040] (2) EPO-PDMS was dissolved in N-methylpyrrolidone, and cis-1,2,3,6-tetrahydrophthalic anhydride was added; under nitrogen protection, the reaction was carried out at 50°C for 2 h to obtain a functional end-capping agent.

[0041] The molar ratio of EPO-PDMS to cis-1,2,3,6-tetrahydrophthalic anhydride is 1:1; the mass ratio of EPO-PDMS to N-methylpyrrolidone is 1:1.

[0042] (3) The functional end-capping agent, lauric anhydride, tetraisopropyl titanate and PA6 resin are melt-blended. The process requirements for the melt-blending stage are as follows: temperature is 230℃; residence time is 5min; screw speed is 60rpm; extrusion into strips, water-cooled pellets, and dried at 80℃ for 24h to obtain modified PA resin.

[0043] The mass ratio of the functional end-capping agent, lauric anhydride, tetraisopropyl titanate, and PA6 resin is 1:0.5:0.05:100.

[0044] Example 2

[0045] A method for preparing a heat-resistant and corrosion-resistant modified PA material includes the following steps: 10 parts by weight of modified PA resin, 30 parts by weight of PA6 resin, 20 parts by weight of glass fiber, 3 parts by weight of filler (mica powder and nano-hexagonal boron nitride in a mass ratio of 1:1), 10 parts by weight of phosphite, 2 parts by weight of stearamide, and 1 part by weight of antioxidant 1076 are added to a mixer and premixed for 10 minutes. The premixed material is then fed into a twin-screw extruder through the main feed port and extruded at a melting temperature of 280°C. The screw extruder speed is 550 rpm, and the material is cooled with water at a temperature of 20°C. Granulation is performed with a particle size of 3 mm, and the material is dried at 80°C for 4 hours to obtain a heat-resistant and corrosion-resistant modified PA material.

[0046] The preparation method of modified PA resin is as follows:

[0047] (1) Mix bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether, add triethylamine and toluene, and react at 100°C for 8 h under nitrogen protection to obtain EPO-PDMS;

[0048] The molar ratio of bis(3-aminopropyl)-terminated polydimethylsiloxane to polyethylene glycol diglycidyl ether is 1:2.2; the amount of triethylamine used is 0.7% of the total mass of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether; and the amount of toluene used is 3 times the total volume of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether.

[0049] (2) EPO-PDMS was dissolved in N-methylpyrrolidone, and cis-1,2,3,6-tetrahydrophthalic anhydride was added; under nitrogen protection, the reaction was carried out at 70°C for 6 h to obtain a functional end-capping agent.

[0050] The molar ratio of EPO-PDMS to cis-1,2,3,6-tetrahydrophthalic anhydride is 1:1.1; the mass ratio of EPO-PDMS to N-methylpyrrolidone is 1:3.

[0051] (3) The functional end-capping agent, lauric anhydride, tetraisopropyl titanate and PA6 resin are melt-blended. The process requirements for the melt-blending stage are as follows: temperature is 230℃; residence time is 5min; screw speed is 60rpm; extrusion into strips, water-cooled pellets, and dried at 80℃ for 24h to obtain modified PA resin.

[0052] The mass ratio of the functional end-capping agent, lauric anhydride, tetraisopropyl titanate, and PA6 resin is 2:1:0.2:100.

[0053] Example 3

[0054] A method for preparing a heat-resistant and corrosion-resistant modified PA material includes the following steps: 8 parts by weight of modified PA resin, 20 parts by weight of PA6 resin, 15 parts by weight of glass fiber, 2 parts by weight of filler (mica powder and nano-hexagonal boron nitride in a mass ratio of 1:1), 8 parts by weight of N,N-dicyclohexylcarbodiimide, 1.5 parts by weight of solid paraffin, and 0.5 parts by weight of antioxidant 1010 are added to a mixer and premixed for 8 minutes. Then, the premix is ​​fed into a twin-screw extruder through the main feed port and extruded at a melting temperature of 255°C. The screw extruder speed is 450 rpm, and the material is cooled with water at 20°C. Granulation is performed with a particle size of 3 mm, and drying is carried out at 80°C for 4 hours to obtain a heat-resistant and corrosion-resistant modified PA material.

[0055] The preparation method of modified PA resin is as follows:

[0056] (1) Mix bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether, add triethylamine and toluene, and react at 80°C for 6 h under nitrogen protection to obtain EPO-PDMS;

[0057] The molar ratio of bis(3-aminopropyl)-terminated polydimethylsiloxane to polyethylene glycol diglycidyl ether is 1:2.1; the amount of triethylamine used is 0.5% of the total mass of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether; and the amount of toluene used is 2.5 times the total volume of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether.

[0058] (2) EPO-PDMS was dissolved in N-methylpyrrolidone, and cis-1,2,3,6-tetrahydrophthalic anhydride was added; under nitrogen protection, the reaction was carried out at 60°C for 4 h to obtain a functional end-capping agent.

[0059] The molar ratio of EPO-PDMS to cis-1,2,3,6-tetrahydrophthalic anhydride is 1:1.1; the mass ratio of EPO-PDMS to N-methylpyrrolidone is 1:2.

[0060] (3) The functional end-capping agent, lauric anhydride, tetraisopropyl titanate and PA6 resin are melt-blended. The process requirements for the melt-blending stage are as follows: temperature is 230℃; residence time is 5min; screw speed is 60rpm; extrusion into strips, water-cooled pellets, and dried at 80℃ for 24h to obtain modified PA resin.

[0061] The mass ratio of functional end-capping agent, lauric anhydride, tetraisopropyl titanate, and PA6 resin is 1.5:0.8:0.12:100.

[0062] Comparative Example 1

[0063] A method for preparing a heat-resistant and corrosion-resistant modified PA material includes the following steps: 8 parts by weight of modified PA resin, 20 parts by weight of PA6 resin, 15 parts by weight of glass fiber, 2 parts by weight of filler (mica powder and nano-hexagonal boron nitride in a mass ratio of 1:1), 8 parts by weight of N,N-dicyclohexylcarbodiimide, 1.5 parts by weight of solid paraffin, and 0.5 parts by weight of antioxidant 1010 are added to a mixer and premixed for 8 minutes. Then, the premix is ​​fed into a twin-screw extruder through the main feed port and extruded at a melting temperature of 255°C. The screw extruder speed is 450 rpm, and the material is cooled with water at 20°C. Granulation is performed with a particle size of 3 mm, and drying is carried out at 80°C for 4 hours to obtain a heat-resistant and corrosion-resistant modified PA material.

[0064] The preparation method of modified PA resin is as follows:

[0065] (1) Bis(3-aminopropyl)-terminated polydimethylsiloxane and 1,2-epoxy-9-decene were mixed, and triethylamine and toluene were added. The mixture was reacted at 80°C for 6 h under nitrogen protection to obtain E-PDMS.

[0066] The molar ratio of bis(3-aminopropyl)-terminated polydimethylsiloxane to 1,2-epoxy-9-decene is 1:2.1; the amount of triethylamine used is 0.5% of the total mass of bis(3-aminopropyl)-terminated polydimethylsiloxane and 1,2-epoxy-9-decene; and the amount of toluene used is 2.5 times the total volume of bis(3-aminopropyl)-terminated polydimethylsiloxane and 1,2-epoxy-9-decene.

[0067] (2) E-PDMS was dissolved in N-methylpyrrolidone, and cis-1,2,3,6-tetrahydrophthalic anhydride was added; under nitrogen protection, the reaction was carried out at 60°C for 4 h to obtain a functional end-capping agent.

[0068] The molar ratio of E-PDMS to cis-1,2,3,6-tetrahydrophthalic anhydride is 1:1.1; the mass ratio of E-PDMS to N-methylpyrrolidone is 1:2.

[0069] (3) The functional end-capping agent, lauric anhydride, tetraisopropyl titanate and PA6 resin are melt-blended. The process requirements for the melt-blending stage are as follows: temperature is 230℃; residence time is 5min; screw speed is 60rpm; extrusion into strips, water-cooled pellets, and dried at 80℃ for 24h to obtain modified PA resin.

[0070] The mass ratio of functional end-capping agent, lauric anhydride, tetraisopropyl titanate, and PA6 resin is 1.5:0.8:0.12:100.

[0071] Comparative Example 2

[0072] A method for preparing a heat-resistant and corrosion-resistant modified PA material includes the following steps: 8 parts by weight of modified PA resin, 20 parts by weight of PA6 resin, 15 parts by weight of glass fiber, 2 parts by weight of filler (mica powder and nano-hexagonal boron nitride in a mass ratio of 1:1), 8 parts by weight of N,N-dicyclohexylcarbodiimide, 1.5 parts by weight of solid paraffin, and 0.5 parts by weight of antioxidant 1010 are added to a mixer and premixed for 8 minutes. Then, the premix is ​​fed into a twin-screw extruder through the main feed port and extruded at a melting temperature of 255°C. The screw extruder speed is 450 rpm, and the material is cooled with water at 20°C. Granulation is performed with a particle size of 3 mm, and drying is carried out at 80°C for 4 hours to obtain a heat-resistant and corrosion-resistant modified PA material.

[0073] The preparation method of modified PA resin is as follows:

[0074] (1) Mix bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether, add triethylamine and toluene, and react at 80°C for 6 h under nitrogen protection to obtain a functional end-capping agent;

[0075] The molar ratio of bis(3-aminopropyl)-terminated polydimethylsiloxane to polyethylene glycol diglycidyl ether is 1:2.1; the amount of triethylamine used is 0.5% of the total mass of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether; and the amount of toluene used is 2.5 times the total volume of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether.

[0076] (2) The functional end-capping agent, lauric anhydride, tetraisopropyl titanate and PA6 resin are melt-blended. The process requirements for the melt-blending stage are as follows: temperature is 230℃; residence time is 5min; screw speed is 60rpm; extrusion into strips, water-cooled pellets, and dried at 80℃ for 24h to obtain modified PA resin.

[0077] The mass ratio of functional end-capping agent, lauric anhydride, tetraisopropyl titanate, and PA6 resin is 1.5:0.8:0.12:100.

[0078] Comparative Example 3

[0079] A method for preparing a heat-resistant and corrosion-resistant modified PA material includes the following steps: 8 parts by weight of modified PA resin, 20 parts by weight of PA6 resin, 15 parts by weight of glass fiber, 2 parts by weight of filler (mica powder and nano-hexagonal boron nitride in a mass ratio of 1:1), 8 parts by weight of N,N-dicyclohexylcarbodiimide, 1.5 parts by weight of solid paraffin, and 0.5 parts by weight of antioxidant 1010 are added to a mixer and premixed for 8 minutes. Then, the premix is ​​fed into a twin-screw extruder through the main feed port and extruded at a melting temperature of 255°C. The screw extruder speed is 450 rpm, and the material is cooled with water at 20°C. Granulation is performed with a particle size of 3 mm, and drying is carried out at 80°C for 4 hours to obtain a heat-resistant and corrosion-resistant modified PA material.

[0080] The preparation method of modified PA resin is as follows:

[0081] (1) Lauric anhydride, tetraisopropyl titanate and PA6 resin were melt-blended. The process requirements for the melt-blending stage were as follows: temperature was 230℃; residence time was 5min; screw speed was 60rpm; extruded into strips, water-cooled and pelletized, and dried at 80℃ for 24h to obtain modified PA resin.

[0082] The mass ratio of lauric anhydride, tetraisopropyl titanate, and PA6 resin is 2.3:0.12:100.

[0083] Comparative Example 4

[0084] A method for preparing a heat-resistant and corrosion-resistant modified PA material includes the following steps: 8 parts by weight of modified PA resin, 20 parts by weight of PA6 resin, 15 parts by weight of glass fiber, 2 parts by weight of filler (mica powder and nano-hexagonal boron nitride in a mass ratio of 1:1), 8 parts by weight of N,N-dicyclohexylcarbodiimide, 1.5 parts by weight of solid paraffin, and 0.5 parts by weight of antioxidant 1010 are added to a mixer and premixed for 8 minutes. Then, the premix is ​​fed into a twin-screw extruder through the main feed port and extruded at a melting temperature of 255°C. The screw extruder speed is 450 rpm, and the material is cooled with water at 20°C. Granulation is performed with a particle size of 3 mm, and drying is carried out at 80°C for 4 hours to obtain a heat-resistant and corrosion-resistant modified PA material.

[0085] The preparation method of modified PA resin is as follows:

[0086] (1) Mix bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether, add triethylamine and toluene, and react at 80°C for 6 h under nitrogen protection to obtain EPO-PDMS;

[0087] The molar ratio of bis(3-aminopropyl)-terminated polydimethylsiloxane to polyethylene glycol diglycidyl ether is 1:2.1; the amount of triethylamine used is 0.5% of the total mass of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether; and the amount of toluene used is 2.5 times the total volume of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether.

[0088] (2) EPO-PDMS was dissolved in N-methylpyrrolidone, and cis-1,2,3,6-tetrahydrophthalic anhydride was added; under nitrogen protection, the reaction was carried out at 60°C for 4 h to obtain a functional end-capping agent.

[0089] The molar ratio of EPO-PDMS to cis-1,2,3,6-tetrahydrophthalic anhydride is 1:1.1; the mass ratio of EPO-PDMS to N-methylpyrrolidone is 1:2.

[0090] (3) The functional end-capping agent, tetraisopropyl titanate and PA6 resin are melt-blended. The process requirements for the melt-blending stage are as follows: temperature is 230℃; residence time is 5min; screw speed is 60rpm; extrusion into strips, water-cooled pellets, and dried at 80℃ for 24h to obtain modified PA resin.

[0091] The mass ratio of the functional end-capping agent, tetraisopropyl titanate, and PA6 resin is 2.3:0.12:100.

[0092] Comparative Example 5

[0093] A method for preparing a heat-resistant and corrosion-resistant modified PA material includes the following steps: 3 parts by weight of modified PA resin, 25 parts by weight of PA6 resin, 15 parts by weight of glass fiber, 2 parts by weight of filler (mica powder and nano-hexagonal boron nitride in a 1:1 mass ratio), 8 parts by weight of N,N-dicyclohexylcarbodiimide, 1.5 parts by weight of solid paraffin, and 0.5 parts by weight of antioxidant 1010 are added to a mixer and premixed for 8 minutes. The premix is ​​then fed into a twin-screw extruder through the main feed port and extruded at a melting temperature of 255°C. The screw extruder speed is 450 rpm, and the material is cooled with water at 20°C. Granulation with a particle size of 3 mm is performed, and the material is dried at 80°C for 4 hours to obtain a heat-resistant and corrosion-resistant modified PA material.

[0094] The preparation method of modified PA resin is as follows:

[0095] (1) Mix bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether, add triethylamine and toluene, and react at 80°C for 6 h under nitrogen protection to obtain EPO-PDMS;

[0096] The molar ratio of bis(3-aminopropyl)-terminated polydimethylsiloxane to polyethylene glycol diglycidyl ether is 1:2.1; the amount of triethylamine used is 0.5% of the total mass of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether; and the amount of toluene used is 2.5 times the total volume of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether.

[0097] (2) EPO-PDMS was dissolved in N-methylpyrrolidone, and cis-1,2,3,6-tetrahydrophthalic anhydride was added; under nitrogen protection, the reaction was carried out at 60°C for 4 h to obtain a functional end-capping agent.

[0098] The molar ratio of EPO-PDMS to cis-1,2,3,6-tetrahydrophthalic anhydride is 1:1.1; the mass ratio of EPO-PDMS to N-methylpyrrolidone is 1:2.

[0099] (3) The functional end-capping agent, lauric anhydride, tetraisopropyl titanate and PA6 resin are melt-blended. The process requirements for the melt-blending stage are as follows: temperature is 230℃; residence time is 5min; screw speed is 60rpm; extrusion into strips, water-cooled pellets, and dried at 80℃ for 24h to obtain modified PA resin.

[0100] The mass ratio of functional end-capping agent, lauric anhydride, tetraisopropyl titanate, and PA6 resin is 1.5:0.8:0.12:100.

[0101] Comparative Example 6

[0102] A method for preparing a heat-resistant and corrosion-resistant modified PA material includes the following steps: 13 parts by weight of modified PA resin, 15 parts by weight of PA6 resin, 15 parts by weight of glass fiber, 2 parts by weight of filler (mica powder and nano-hexagonal boron nitride in a mass ratio of 1:1), 8 parts by weight of N,N-dicyclohexylcarbodiimide, 1.5 parts by weight of solid paraffin, and 0.5 parts by weight of antioxidant 1010 are added to a mixer and premixed for 8 minutes. The premixed material is then fed into a twin-screw extruder through the main feed port and extruded at a melting temperature of 255°C. The screw extruder speed is 450 rpm, and the material is cooled with water at a temperature of 20°C. Granulation is performed with a particle size of 3 mm, and drying is carried out at 80°C for 4 hours to obtain a heat-resistant and corrosion-resistant modified PA material.

[0103] The preparation method of modified PA resin is as follows:

[0104] (1) Mix bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether, add triethylamine and toluene, and react at 80°C for 6 h under nitrogen protection to obtain EPO-PDMS;

[0105] The molar ratio of bis(3-aminopropyl)-terminated polydimethylsiloxane to polyethylene glycol diglycidyl ether is 1:2.1; the amount of triethylamine used is 0.5% of the total mass of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether; and the amount of toluene used is 2.5 times the total volume of bis(3-aminopropyl)-terminated polydimethylsiloxane and polyethylene glycol diglycidyl ether.

[0106] (2) EPO-PDMS was dissolved in N-methylpyrrolidone, and cis-1,2,3,6-tetrahydrophthalic anhydride was added; under nitrogen protection, the reaction was carried out at 60°C for 4 h to obtain a functional end-capping agent.

[0107] The molar ratio of EPO-PDMS to cis-1,2,3,6-tetrahydrophthalic anhydride is 1:1.1; the mass ratio of EPO-PDMS to N-methylpyrrolidone is 1:2.

[0108] (3) The functional end-capping agent, lauric anhydride, tetraisopropyl titanate and PA6 resin are melt-blended. The process requirements for the melt-blending stage are as follows: temperature is 230℃; residence time is 5min; screw speed is 60rpm; extrusion into strips, water-cooled pellets, and dried at 80℃ for 24h to obtain modified PA resin.

[0109] The mass ratio of functional end-capping agent, lauric anhydride, tetraisopropyl titanate, and PA6 resin is 1.5:0.8:0.12:100.

[0110] The following section further examines the effects of the various embodiments and comparative examples prepared according to the present invention:

[0111] (1) Heat resistance test: heat distortion temperature (HDT): ASTM D648, load 1.82MPa; thermogravimetric analysis (TGA): under nitrogen atmosphere, heating rate 10℃ / min, record 5% weight loss temperature (Td5%); long-term heat aging: treated at 200℃ for 1000h, test the tensile strength retention rate.

[0112] (2) Corrosion resistance test: Chemical reagent immersion: 10% hydrochloric acid solution (80℃×72h); 10% sodium hydroxide solution (80℃×72h); Mass loss rate: Calculate the mass change before and after immersion;

[0113] (3) Flame retardancy verification: UL94 rating: vertical burning test; limiting oxygen index (LOI): ASTM D2863.

[0114] The test results are as follows. The results are recorded in Tables 1 and 2.

[0115] Table 1: Test Results

[0116]

[0117] Table 2: Test Results

[0118]

[0119] Based on the data in Tables 1 and 2, a comparison of the embodiments and comparative examples of the present invention shows that the relevant performance of Examples 1-3 is significantly better than that of Comparative Examples 1-6. Comparative Example 1 (mono-epoxy end-capped) has insufficient functionality, resulting in a decrease in molecular chain crosslinking density and reduced heat resistance. Comparative Example 2 (without anhydride modification) lacks carboxyl end-capping, which cannot effectively inhibit the degradation of PA end groups, resulting in a low long-term heat aging retention rate. The various properties of Comparative Example 3 (without functional end-capping agent) and Comparative Example 4 (without lauric anhydride) are lower than those of Examples 1-3, proving that there is a synergistic effect between ordinary end-capping agents and functional end-capping agents. Comparative Example 5 has insufficient modified resin (3 parts), and its performance is close to that of basic PA6. Comparative Example 6 has excessive modified resin (13 parts), which leads to phase separation, resulting in a decrease in corrosion resistance and heat aging retention rate.

[0120] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A heat-resistant and corrosion-resistant modified PA material, characterized in that, By weight parts, including the following components: modified PA resin 5-10 parts, PA6 resin 10-30 parts, glass fiber 10-20 parts, filler 1-3 parts, stabilizer 5-10 parts, lubricant 1-2 parts, antioxidant 0.1-1 parts; The preparation method of the modified PA resin is: (1) mixing the organic silicon intermediate and the epoxy linker, adding a catalyst and a solvent, reacting for 4-8 h under nitrogen protection, to obtain EPO-PDMS; (2) dissolving the EPO-PDMS in N-methyl pyrrolidone, adding an acid anhydride monomer, and reacting for 2-6 h under nitrogen protection to obtain a functional capping agent; (3) melt blending the functional capping agent, lauric anhydride, and organic titanate with the PA resin, extruding and granulating to obtain the modified PA resin; In step (1), the organic silicon intermediate is bis(3-aminopropyl) terminated polydimethylsiloxane, and the molecular weight is 600-2000; In step (1), the epoxy linker is polyethylene glycol diglycidyl ether; In step (2), the acid anhydride monomer is one of cis-1,2,3,6-tetrahydrophthalic anhydride and hexahydrophthalic anhydride.

2. The heat-resistant and corrosion-resistant modified PA material according to claim 1, characterized in that, In step (1), the molar ratio of the organic silicon intermediate to the epoxy linker is 1:2-2.2, and the amount of catalyst is 0.3-0.7% of the total mass of the organic silicon intermediate and the epoxy linker.

3. The heat-resistant and corrosion-resistant modified PA material according to claim 1, characterized in that, In step (2), the molar ratio of EPO-PDMS to acid anhydride monomer is 1:1-1.

1.

4. The heat-resistant and corrosion-resistant modified PA material according to claim 1, characterized in that, In step (3), the PA resin is one of PA6 resin and PA66 resin.

5. The heat-resistant and corrosion-resistant modified PA material according to claim 1, characterized in that, In step (3), the mass ratio of the functional capping agent, lauric anhydride, organic titanate, and PA resin is 1-2:0.5-1:0.05-0.2:

100.

6. A process for the preparation of a heat resistant and corrosion resistant modified PA material according to any one of claims 1-5, characterized in that, The following steps are included: The modified PA resin, PA6 resin, glass fiber, filler, stabilizer, lubricant, and antioxidant are added to a mixing blender for premixing, and then the premixed material is added to a twin-screw extruder from the main feeding port, extruded, water-cooled, and granulated to obtain a heat-resistant and corrosion-resistant modified PA material.

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