Nylon 66 functional master batch as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of nylon 66, and particularly relates to a nylon 66 functional master batch as well as a preparation method and application thereof. The nylon 66 functional master batch provided by the invention is prepared from the following preparation raw materials in parts by mass: 50 to 70 parts of a nylon 66 matrix, 30 to 50 parts of modified wollastonite fibers, 0.6 to 1.2 parts of an antistatic agent, 0.3 to 0.8 part of a flame retardant and 0.3 to 0.8 part of an anti-aging agent. According to the invention, the modified wollastonite fiber is used as a reinforcing phase, the situation that the nylon 66 is easy to cause stress concentration to cause cracking when the climate is dry is improved by using the modified wollastonite fiber, and the comprehensive performance of the nylon 66 functional master batch is improved by adding the antistatic agent, the flame retardant and the anti-aging agent; a raw material with high strength, high toughness, antistatic property, high flame retardance, good aging resistance and good dimensional stability is provided for the automobile fuel tank.

Description

Technical Field

[0001] This invention belongs to the field of nylon 66 technology, specifically relating to a nylon 66 functional masterbatch, its preparation method, and its application. Background Technology

[0002] Nylon, also known as polyamide (PA), is a general term for a series of thermoplastic resins whose main molecular chain contains repeating -NHCO- (amide groups). Based on the different molecular chains, it can be divided into aliphatic nylon, aliphatic-aromatic nylon, and aromatic nylon. Among them, aliphatic nylon has the most varieties, the highest production volume, and the widest application. Nylon 66 is the most important product among aliphatic nylons. It is synthesized through a condensation reaction using hexamethylenediamine and adipic acid as monomers. As an engineering plastic with excellent mechanical properties, it has advantages such as non-toxicity, light weight, excellent mechanical properties, and good wear resistance. Therefore, it can replace metals such as iron and copper in the manufacture of various parts.

[0003] Currently, nylon 66 is relatively less involved in the traditional automotive parts industry. However, for the vision of modern automobiles, lightweight and streamlined designs are essential to improve vehicle speed. For fuel tanks, nylon 66 can be used as a raw material, employing molding to design more complex structures that can be more flexibly mounted on the chassis, thus realizing these visions. However, traditional nylon 66 does not meet the strength and other performance requirements of automotive fuel tanks. Furthermore, in dry winter air with low humidity, nylon products cannot absorb sufficient moisture, making them prone to cracking due to stress concentration. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a nylon 66 functional masterbatch, its preparation method and application. The present invention uses modified wollastonite fiber as a reinforcing phase to improve the situation where nylon 66 is prone to stress concentration and cracking when the climate is dry, and provides a high-strength, high-toughness, antistatic, flame-retardant and aging-resistant raw material for automobile fuel tanks.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a nylon 66 functional masterbatch, comprising the following raw materials by weight:

[0007]

[0008] Preferably, the method for preparing the modified wollastonite fiber includes the following steps: pulverizing and screening wollastonite sequentially to obtain wollastonite fiber; mixing the wollastonite fiber with a compound modifier and pulverizing and modifying it to obtain modified wollastonite fiber; the compound modifier includes a silane coupling agent and stearic acid.

[0009] Preferably, the silane coupling agent is one or more selected from vinyltrichlorosilane, vinyltriethoxysilane, anilinemethyltrimethoxysilane, anilinemethyltrimethoxysilane, and γ-aminopropyltriethoxysilane.

[0010] Preferably, the mass ratio of the silane coupling agent to stearic acid is 5 to 10:3.

[0011] Preferably, the mass ratio of the compound modifier to wollastonite fiber is 1:10 to 20.

[0012] Preferably, the antistatic agent is one or more selected from polyethylene oxide, carbonic acid, sulfonic acid, dialkylpropanetriol, and alkylamide.

[0013] Preferably, the flame retardant is one or more of red phosphorus, phosphate, and ammonium polyphosphate.

[0014] Preferably, the antioxidant is one or more selected from N-phenyl-α-aniline, N-phenyl-β-naphthylamine, p-phenylenediamine, N-N'-diphenyl-p-phenylenediamine, and ketamine.

[0015] This invention also provides a method for preparing the nylon 66 functional masterbatch described in the above technical solution, comprising the following steps:

[0016] Modified wollastonite fiber, nylon 66 matrix, antistatic agent, flame retardant and antioxidant are mixed and then melt-extruded and granulated in sequence to obtain nylon 66 functional masterbatch.

[0017] The present invention also provides the application of the nylon 66 functional masterbatch described in the above technical solution or the nylon 66 functional masterbatch prepared by the preparation method described in the above technical solution in automotive fuel tanks.

[0018] This invention provides a nylon 66 functional masterbatch, comprising the following raw materials by weight:

[0019]

[0020] This invention uses modified wollastonite fiber as a reinforcing phase to improve the stress concentration and cracking problem of nylon 66 when the climate is dry. By adding antistatic agents, flame retardants, and anti-aging agents, the overall performance of nylon 66 functional masterbatch is improved, providing a raw material for automotive fuel tanks with high strength, high toughness, antistatic properties, high flame retardancy, good aging resistance, and good dimensional stability. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the process for preparing wollastonite fiber modified PA66 material (sample to be tested) using nylon 66 functional masterbatch in an embodiment of the present invention. Detailed Implementation

[0022] This invention provides a nylon 66 functional masterbatch, comprising the following raw materials by weight:

[0023]

[0024] Unless otherwise specified, the present invention does not have special requirements on the source of raw materials used, and commercially available products well known to those skilled in the art can be used.

[0025] The raw materials for preparing the nylon 66 functional masterbatch provided by the present invention include 50 to 70 parts by weight of nylon 66 matrix, specifically 50, 60 or 70 parts in the embodiments.

[0026] As one embodiment, the method for preparing the nylon 66 matrix includes the following steps:

[0027] A neutralization reaction was carried out by mixing hexamethylenediamine, adipic acid and water to obtain a system containing nylon 66 salt;

[0028] The system containing nylon 66 salt was filtered and preliminarily dehydrated, and then subjected to a polycondensation reaction. The resulting polycondensation product was flash-evaporated, extruded, cooled and dried to obtain the nylon 66 matrix.

[0029] In one embodiment, the molar ratio of hexamethylenediamine to adipic acid is 1:1; the hexamethylenediamine, adipic acid, and water are mixed as follows: hexamethylenediamine and water are mixed, and adipic acid is added to the resulting aqueous solution of hexamethylenediamine; the concentration of hexamethylenediamine in the aqueous solution is 20-35 wt%, specifically 30 wt% in this embodiment; the temperature of the neutralization reaction is 40-50°C, specifically 50°C in this embodiment, and the time is 2-4 hours, specifically 4 hours in this embodiment; the filtration equipment used is a salt filter, specifically activated carbon filter in this embodiment. The apparatus is mainly used to adsorb soluble impurities in solution; the heating temperature for the preliminary dehydration is 85-105℃, specifically 95℃ in this embodiment; the preliminary dehydration increases the mass content of nylon 66 salt in the system containing nylon 66 salt from 50% to 70-85%, specifically 70% in this embodiment; the temperature for the polycondensation reaction is 230-290℃, specifically 230℃ in this embodiment, the time is 4-8 hours, specifically 8 hours in this embodiment, and the pressure is 1.7-2.2 MPa, specifically 1.7 MPa in this embodiment. Hexamethylenediamine and adipic acid undergo a polycondensation reaction to generate polyhexamethylene adipamide.

[0030] In the raw materials, the amino group of hexamethylenediamine is basic, while the carboxyl group of adipic acid is acidic. The amino group (-NH2) of hexamethylenediamine reacts with the carboxyl group (-COOH) of adipic acid in an acid-base neutralization reaction (not a condensation polymerization reaction), which essentially involves proton transfer to form hexamethylenediamine adipate (commonly known as 66 salt), with the chemical formula […]. +H3N-(CH2)6-NH3 + · - OOC-(CH2)4-COO - The molar ratio of hexamethylenediamine to adipic acid must be strictly maintained at 1:1 because the nylon 66 prepared in this invention has a high molecular weight (20,000-30,000). An excess of one will end-cap and cause the reaction to stop, resulting in a low molecular weight.

[0031] In one embodiment, the flash evaporation temperature is 100–120°C, specifically 110°C in this embodiment, and the time is 6–8 hours, specifically 6 hours in this embodiment; the flash evaporation continues until the water content of the polycondensation product is less than 0.5 wt%; the number average molecular weight of the polycondensation product after flash evaporation is 15,000–30,000, specifically 20,000–30,000 in this embodiment; the extrusion pressure is 4–10 MPa, specifically 8 MPa in this embodiment; the drying temperature is 100–120°C, specifically 120°C in this embodiment, and the time is 6–12 hours, specifically 10 hours in this embodiment.

[0032] Based on 1 part by mass of nylon 66 matrix, the raw materials for preparing the nylon 66 functional masterbatch provided by the present invention include 30 to 50 parts by mass of modified wollastonite fiber, specifically 30, 40 or 50 parts in the specific embodiments.

[0033] As one embodiment, the preparation method of the modified wollastonite fiber includes the following steps: wollastonite is crushed and screened sequentially to obtain wollastonite fiber; the wollastonite fiber is mixed with a compound modifier and then crushed and modified to obtain modified wollastonite fiber.

[0034] In one embodiment, the compound modifier includes a silane coupling agent and stearic acid; the silane coupling agent is one or more of vinyltrichlorosilane, vinyltriethoxysilane, anilinemethyltrimethoxysilane, anilinemethyltrimethoxysilane, and γ-aminopropyltriethoxysilane, with vinyltrichlorosilane being used in a specific embodiment; the mass ratio of the silane coupling agent to stearic acid is 5 to 10:3, with 5:3 or 6:3 being used in a specific embodiment.

[0035] In one embodiment, the mass ratio of the compound modifier to wollastonite fiber is 1:10 to 20, and in specific embodiments it is 1:10, 1:15 or 1:20.

[0036] In one embodiment, the diameter of the wollastonite fiber is 1–10 μm, specifically 1 μm in this embodiment, and the aspect ratio is 7–30:1, specifically 30:1 in this embodiment. The nylon 66 functional masterbatch prepared using wollastonite fibers within the above aspect ratio range exhibits significantly improved longitudinal strength and toughness.

[0037] In one embodiment, the pulverization is mechanical pulverization; the pulverized wollastonite is 100-mesh long needle-shaped wollastonite; the screening is performed using a 200-mesh vibrating screen; the present invention separates the pulverized wollastonite fibers and impurities through screening; the sedimentation value of the wollastonite fibers is ≥80mL, specifically 85mL in the embodiment, and the whiteness is ≥70%, specifically 80% in the embodiment.

[0038] In one embodiment, the equipment used for pulverization and modification is an air jet mill; the temperature for pulverization and modification is 80–90°C, specifically 85–90°C in this embodiment, and the time is 20–50 min, specifically 30 min in this embodiment; the rate at which the compound modifier enters the air jet mill is 3–5 L / h, specifically 4 L / h in this embodiment; the rotational speed of the air jet mill during the pulverization and modification process is 3000–3500 rpm, specifically 3000–3200 rpm in this embodiment.

[0039] Wollastonite is used as an inorganic reinforcing filler, and nylon 66 is used as the organic resin matrix. Adding a compound modifier consisting of stearic acid and a silane coupling agent to the functional masterbatch formulation can transform the hydrophilic surface properties of wollastonite into hydrophobic properties, thereby effectively improving the interfacial compatibility between wollastonite and the nylon 66 matrix and enhancing the overall performance of the masterbatch. The compound modifier mainly bonds with wollastonite through hydrogen bonds and -Si-O- chemical bonds.

[0040] Based on 1 part by mass of nylon 66 matrix, the raw materials for preparing the nylon 66 functional masterbatch provided by the present invention include 0.6 to 1.2 parts by mass of antistatic agent, specifically 0.6, 0.8, or 1 part in the specific embodiments.

[0041] In one embodiment, the antistatic agent is one or more of polyethylene oxide, carbonic acid, sulfonic acid, dialkylpropanetriol, and alkylamide, with polyethylene oxide being used in a specific embodiment. The antistatic agent primarily eliminates the accumulation of surface charge on the product, preventing the adhesion of dust and other impurities.

[0042] Based on 1 part by mass of nylon 66 matrix, the raw materials for preparing the nylon 66 functional masterbatch provided by the present invention include 0.3 to 0.8 parts by mass of flame retardant, specifically 0.3, 0.5, or 0.8 parts in the specific embodiments.

[0043] In one embodiment, the flame retardant is one or more of red phosphorus, phosphate, and ammonium polyphosphate, with ammonium polyphosphate being used in a specific embodiment. The flame retardant used in this invention is a high-efficiency halogen-free flame retardant, which is non-toxic and non-polluting, and mainly serves to retard the product.

[0044] Based on 1 part by mass of nylon 66 matrix, the raw materials for preparing the nylon 66 functional masterbatch provided by the present invention include 0.3 to 0.8 parts by mass of antioxidant, specifically 0.3, 0.5 or 0.8 parts in the specific embodiments.

[0045] In one embodiment, the antioxidant is one or more of N-phenyl-α-aniline, N-phenyl-β-naphthylamine, p-phenylenediamine, N-N'-diphenyl-p-phenylenediamine, and ketamines, with p-phenylenediamine being a specific example. The antioxidant has the functions of inhibiting oxidation, heat resistance, light resistance, and preventing aging.

[0046] This invention boasts advantages such as a scientifically sound design, simple operation, low production cost, and ease of large-scale production. Furthermore, it can improve the mechanical strength, flexibility, antistatic properties, and aging resistance of traditional nylon resins. In addition, this invention can enhance the compatibility between modified wollastonite fibers and the nylon 66 matrix, which is of great significance for improving the overall performance and expanding the application fields of this type of modified material.

[0047] This invention also provides a method for preparing the nylon 66 functional masterbatch described in the above technical solution, comprising the following steps:

[0048] Modified wollastonite fiber, nylon 66 matrix, antistatic agent, flame retardant and antioxidant are mixed and then melt-extruded and granulated in sequence to obtain nylon 66 functional masterbatch.

[0049] In one embodiment, the equipment used for melt extrusion is a twin-screw extruder; the temperature of melt extrusion is 250-280°C, specifically 260°C in this embodiment, and the pressure is 3-8 MPa, specifically 5 MPa in this embodiment; the particle size of the granulated material is 1-10 mm, specifically 2-3 mm or 3-5 mm in this embodiment.

[0050] Figure 1 This is a schematic diagram illustrating the process of preparing wollastonite fiber-modified PA66 material (sample to be tested) using nylon 66 functional masterbatch in an embodiment of the present invention. Figure 1 As shown, in this invention, wollastonite is mechanically pulverized, and the resulting wollastonite sample and modifier are modified in an air-jet abrasive chamber to obtain wollastonite fiber modified product. Nylon 66 salt is synthesized using hexamethylenediamine and adipic acid, and then passed through a metering tank, an intermediate tank, and a concentration tank to a reaction tank for polycondensation reaction. The resulting product is flash-evaporated, cooled, and dried to obtain PA66 product. The wollastonite fiber modified product and PA66 product are mixed in metered amounts, and antistatic agent, flame retardant, and antioxidant are added. The mixture is then melt-extruded and granulated using a twin-screw extruder to obtain Nylon 66 functional masterbatch. The Nylon 66 functional masterbatch and PA66 are melt-mixed and cooled to obtain wollastonite fiber modified PA66 material (sample to be tested).

[0051] The present invention also provides the application of the nylon 66 functional masterbatch described in the above technical solution or the nylon 66 functional masterbatch prepared by the preparation method described in the above technical solution in automotive fuel tanks.

[0052] The present invention does not have any particular limitation on the application of the nylon 66 functional masterbatch in automotive fuel tanks; any application method known in the art can be used.

[0053] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0054] Example 1

[0055] (1) Preparation of modified wollastonite fibers

[0056] First, the silica ore is mechanically crushed into 100-mesh long needle-shaped wollastonite. Then, it is screened through a 200-mesh vibrating screen to separate the broken fibers and impurities. Wollastonite fibers with a settling value ≥80mL and whiteness ≥70% (length-to-diameter ratio 30:1, diameter 1μm) are selected. The wollastonite fibers are then fed into an air-jet abrasive chamber via airflow. Vinyltrichlorosilane and stearic acid are mixed at a mass ratio of 6:3 to form a compound modifier. The modifier is then fed into the air-jet abrasive chamber at a rate of 4L / h. The mass ratio of the compound modifier to the wollastonite fibers is 1:10. The pulverization and modification are completed in one pass through the air-jet abrasive chamber. The internal temperature of the air-jet abrasive chamber is 90℃, and the rotation speed is 3000rpm, resulting in modified wollastonite fibers.

[0057] (2) Preparation of Nylon 66 matrix

[0058] Using an aqueous solution method, purified hexamethylenediamine was prepared into a 30 wt% aqueous solution, and an equimolar amount of adipic acid was added. The mixture was neutralized at 50°C for 4 hours to produce nylon 66 salt. This salt was fed in batches into a metering tank and then into an intermediate tank. A nylon 66 salt supply pump continuously fed the salt into a concentration tank through a salt filter (activated carbon filter) and a salt preheater. Moisture was removed by heating at 95°C, increasing the mass fraction of the nylon 66 salt to 70%. The reactor supply pump then concentrated the salt. The salt solution was then sent out and entered the reactor through a salt preheater. The temperature was controlled at 230℃ and the pressure at 1.7MPa. The polycondensation reaction was carried out under high temperature and high pressure for 8 hours. After that, the pressure was released and it was continuously fed into a flash evaporator to maintain the pressure at 0.1MPa. The water content was evaporated for 45 minutes until the water content was less than 0.5wt% and the number average molecular weight was 20,000 to 30,000. After completion, the material was pressed out at 8MPa, cooled to room temperature, and then dried at 120℃ for 10 hours to obtain the nylon 66 matrix.

[0059] (3) Preparation of Nylon 66 functional masterbatch

[0060] By mass, 30 parts of the modified wollastonite fiber and 70 parts of nylon 66 matrix are mixed evenly, and 0.6 parts of polyethylene oxide, 0.3 parts of ammonium polyphosphate and 0.3 parts of p-phenylenediamine are added. The mixture is placed in a twin-screw extruder and melt-extruded at 260°C and 5MPa, and then granulated to obtain nylon 66 functional masterbatch with a particle size of 2-3 mm.

[0061] The nylon 66 functional masterbatch and nylon 66 matrix were melt-mixed at 270℃ at a mass ratio of 1:1 and then cooled to obtain the sample to be tested.

[0062] Example 2

[0063] (1) Preparation of modified wollastonite fibers

[0064] First, the silica ore is mechanically crushed into 100-mesh long needle-shaped wollastonite. Then, it is screened through a 200-mesh vibrating screen to separate the broken fibers and impurities. Wollastonite fibers with a settling value ≥80mL and whiteness ≥70% (length-to-diameter ratio 30:1, diameter 1μm) are selected. The wollastonite fibers are then fed into an air-jet abrasive chamber via airflow. Vinyltrichlorosilane and stearic acid are mixed at a mass ratio of 5:3 to form a compound modifier. The modifier is then fed into the air-jet abrasive chamber at a rate of 4L / h. The mass ratio of the compound modifier to the wollastonite fibers is 1:10. The pulverization and modification are completed in one pass through the air-jet abrasive chamber. The internal temperature of the air-jet abrasive chamber is 90℃, and the rotation speed is 3000rpm, resulting in modified wollastonite fibers.

[0065] (2) Preparation of Nylon 66 matrix

[0066] Using an aqueous solution method, purified hexamethylenediamine was prepared into a 30 wt% aqueous solution, and an equimolar amount of adipic acid was added. The mixture was neutralized at 50°C for 4 hours to produce nylon 66 salt. This salt was fed in batches into a metering tank and then into an intermediate tank. A nylon 66 salt supply pump continuously fed the salt into a concentration tank through a salt filter (activated carbon filter) and a salt preheater. Moisture was removed by heating at 95°C, increasing the mass fraction of the nylon 66 salt to 70%. The reactor supply pump then concentrated the salt. The salt solution was then sent out and entered the reactor through a salt preheater. The temperature was controlled at 230℃ and the pressure at 1.7MPa. The polycondensation reaction was carried out under high temperature and high pressure for 8 hours. After that, the pressure was released and it was continuously fed into a flash evaporator to maintain the pressure at 0.1MPa. The water content was evaporated for 45 minutes until the water content was less than 0.5wt% and the number average molecular weight was 20,000 to 30,000. After completion, the material was pressed out at 8MPa, cooled to room temperature, and then dried at 120℃ for 10 hours to obtain the nylon 66 matrix.

[0067] (3) Preparation of Nylon 66 functional masterbatch

[0068] By mass, 40 parts of the modified wollastonite fiber and 60 parts of nylon 66 matrix were mixed evenly, and 0.8 parts of polyethylene oxide, 0.5 parts of ammonium polyphosphate and 0.5 parts of p-phenylenediamine were added. The mixture was placed in a twin-screw extruder and melt-extruded at 260°C and 5MPa, and granulated to obtain nylon 66 functional masterbatch with a particle size of 2-3 mm.

[0069] The nylon 66 functional masterbatch and nylon 66 matrix were melt-mixed at 270℃ at a mass ratio of 2:1 and then cooled to obtain the sample to be tested.

[0070] Example 3

[0071] (1) Preparation of modified wollastonite fibers

[0072] First, the silica ore is mechanically crushed into 100-mesh long needle-shaped wollastonite. Then, it is screened through a 200-mesh vibrating screen to separate the broken fibers and impurities. Wollastonite fibers with a settling value ≥80mL and whiteness ≥70% (length-to-diameter ratio 30:1, diameter 1μm) are selected. The wollastonite fibers are then fed into an air-jet abrasive chamber via airflow. Vinyltrichlorosilane and stearic acid are mixed at a mass ratio of 5:3 to form a compound modifier. The modifier is then fed into the air-jet abrasive chamber at a rate of 4L / h. The mass ratio of the compound modifier to the wollastonite fibers is 1:20. The crushing and modification are completed in one pass through the air-jet abrasive chamber. The internal temperature of the air-jet abrasive chamber is 90℃, and the rotation speed is 3000rpm, resulting in modified wollastonite fibers.

[0073] (2) Preparation of Nylon 66 matrix

[0074] Using an aqueous solution method, purified hexamethylenediamine was prepared into a 30 wt% aqueous solution, and an equimolar amount of adipic acid was added. The mixture was neutralized at 50°C for 4 hours to produce nylon 66 salt. This salt was fed in batches into a metering tank and then into an intermediate tank. A nylon 66 salt supply pump continuously fed the salt into a concentration tank through a salt filter (activated carbon filter) and a salt preheater. Moisture was removed by heating at 95°C, increasing the mass fraction of the nylon 66 salt to 70%. The reactor supply pump then concentrated the salt. The salt solution was then sent out and entered the reactor through a salt preheater. The temperature was controlled at 230℃ and the pressure at 1.7MPa. The polycondensation reaction was carried out under high temperature and high pressure for 8 hours. After that, the pressure was released and it was continuously fed into a flash evaporator to maintain the pressure at 0.1MPa. The water content was evaporated for 45 minutes until the water content was less than 0.5wt% and the number average molecular weight was 20,000 to 30,000. After completion, the material was pressed out at 8MPa, cooled to room temperature, and then dried at 120℃ for 10 hours to obtain the nylon 66 matrix.

[0075] (3) Preparation of Nylon 66 functional masterbatch

[0076] By mass fraction, 50 parts of the modified wollastonite fiber and 50 parts of nylon 66 matrix are mixed evenly, 1 part of polyethylene oxide, 0.8 parts of ammonium polyphosphate and 0.8 parts of p-phenylenediamine are added, and the mixture is placed in a twin-screw extruder and melt-extruded at 260°C and 5MPa to granulate, thereby obtaining nylon 66 functional masterbatch with a particle size of 2-3 mm.

[0077] The nylon 66 functional masterbatch and nylon 66 matrix were melt-mixed at 270℃ at a mass ratio of 3:1 and then cooled to obtain the sample to be tested.

[0078] Comparative Example 1

[0079] The difference from Example 1 is that only the nylon 66 matrix is ​​prepared, without modifying wollastonite or preparing nylon 66 functional masterbatch, that is, only step (2) in Example 1 is included.

[0080] Comparative Example 2

[0081] The difference from Example 1 is that the obtained nylon 66 functional masterbatch is used directly for testing. That is, it does not include the step (3) of Example 1, which involves melting and mixing the nylon 66 functional masterbatch and the nylon 66 matrix at a certain mass ratio.

[0082] Performance testing

[0083] The properties of the wollastonite fiber modified nylon 66 materials obtained in Examples 1 to 3 were tested. The test methods for each property are as follows: tensile strength was tested according to ASTM D-638, fracture toughness was tested according to ASTM E-399, antistatic properties were tested according to GB / T 15738-2008, and aging resistance was tested according to GB / T 7141-2008.

[0084] Aging Resistance Testing: Accelerated thermal aging tests were conducted on wollastonite fiber-modified composite materials, and their thermal aging mechanical properties were analyzed. Test specimens were then prepared from the wollastonite fiber-modified composite materials. Thermal aging tests were performed on the materials according to GB / T 7141-2008, "Plastics - Test Method for Thermal Aging". The test specimens were placed in a 401B type thermal aging oven and subjected to thermal aging at four temperatures: 110℃, 120℃, 130℃, and 140℃, for a cumulative total of 48 hours. Sampling was conducted at each test temperature for 12 hours, 24 hours, 36 hours, and 480 hours. During the thermal aging performance tests, the specific requirements of GB / T 7141-2008 were strictly followed, ensuring stable environmental conditions and proper sample handling to guarantee the accuracy and reliability of the test results.

[0085] Antistatic testing: After cleaning the sample, prepare the volume resistivity meter. Place the sample in the testing equipment, ensuring good and stable contact between the sample and the electrodes. Apply a constant voltage to the testing equipment according to the requirements of GB / T 15738-2008, and measure the resistance between the samples. Based on the measured resistance value and the sample's geometry and shape, calculate the area resistivity using an appropriate formula. When performing surface resistivity testing, strictly follow the specific requirements of GB / T15738-2008, ensuring stable environmental conditions and proper sample handling during the testing process to guarantee the accuracy and reliability of the test results.

[0086] The test results for the above content are shown in Tables 1 to 6.

[0087] Table 1. Technical specifications of the samples prepared in Example 1. Each specification was tested three times.

[0088]

[0089] Table 2. Aging resistance properties of the test samples prepared in Example 1 (comparison of tensile strength before and after thermal aging).

[0090] Heat aging tensile strength / MPa 131 131 131 131 Temperature / °C 110 120 130 140 Tensile strength without heat aging / MPa 127.7 127.1 126.5 126.3 Decrease rate / % 2.5 3 3.4 3.6

[0091] Note: The performance indicators of the sample before and after thermal aging at four different temperatures were tested once at each temperature, for a total of four tests.

[0092] Table 3 shows the technical specifications of the samples prepared in Example 2. Each specification was tested three times.

[0093]

[0094] Table 4. Aging resistance properties of the test samples prepared in Example 2 (comparison of tensile strength before and after thermal aging).

[0095] Heat aging tensile strength / MPa 168 168 168 168 Temperature / °C 110 120 130 140 Tensile strength without heat aging / MPa 164.1 163.8 162.9 162.5 Decrease rate / % 2.3 2.5 3.0 3.3

[0096] Note: The performance indicators of the sample before and after thermal aging at four different temperatures were tested once at each temperature, for a total of four tests.

[0097] Table 5 shows the technical specifications of the samples prepared in Example 3, with each specification tested three times.

[0098]

[0099] Table 6. Aging resistance properties of the samples prepared in Example 3 (comparison of tensile strength before and after thermal aging).

[0100] Heat aging tensile strength / MPa 195 195 195 195 Temperature / °C 110 120 130 140 Tensile strength without heat aging / MPa 191.1 190.3 189.5 189.1 Decrease rate / % 2.0 2.4 2.8 3.0

[0101] Note: The performance indicators of the sample before and after thermal aging at four different temperatures were tested once at each temperature, for a total of four tests.

[0102] As shown in Tables 1-6, the tensile strength and fracture toughness of the composite material both increase with the increase of the percentage of wollastonite fiber content. Furthermore, the surface resistivity, oxygen index, and aging resistance of the tested sample all improve with the increase of the content of antistatic agent, flame retardant, and antioxidant. In summary, the nylon 66 functional masterbatch prepared by this invention exhibits improved strength, excellent fracture toughness, and also possesses antistatic, flame retardant, and aging resistance properties, meeting the daily operating requirements of automotive fuel tanks.

[0103] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A nylon 66 functional masterbatch, characterized in that, The following raw materials are included in the preparation by mass parts:

2. The nylon 66 functional masterbatch according to claim 1, characterized in that, The preparation method of the modified wollastonite fiber includes the following steps: wollastonite is crushed and screened sequentially to obtain wollastonite fiber; the wollastonite fiber is mixed with a compound modifier and then crushed and modified to obtain modified wollastonite fiber; the compound modifier includes a silane coupling agent and stearic acid.

3. The nylon 66 functional masterbatch according to claim 2, characterized in that, The silane coupling agent is one or more of vinyltrichlorosilane, vinyltriethoxysilane, anilinemethyltrimethoxysilane, anilinemethyltrimethoxysilane, and γ-aminopropyltriethoxysilane.

4. The nylon 66 functional masterbatch according to claim 2, characterized in that, The mass ratio of the silane coupling agent to stearic acid is 5 to 10:

3.

5. The nylon 66 functional masterbatch according to claim 2, characterized in that, The mass ratio of the compound modifier to wollastonite fiber is 1:10 to 20.

6. The nylon 66 functional masterbatch according to claim 1, characterized in that, The antistatic agent is one or more of polyethylene oxide, carbonic acid, sulfonic acid, dialkylpropanetriol, and alkylamide.

7. The nylon 66 functional masterbatch according to claim 1, characterized in that, The flame retardant is one or more of red phosphorus, phosphate, and ammonium polyphosphate.

8. The nylon 66 functional masterbatch according to claim 1, characterized in that, The antioxidant is one or more of N-phenyl-α-aniline, N-phenyl-β-naphthylamine, p-phenylenediamine, N-N'-diphenyl-p-phenylenediamine, and ketamine.

9. A method for preparing the nylon 66 functional masterbatch according to any one of claims 1 to 8, characterized in that, Includes the following steps: Modified wollastonite fiber, nylon 66 matrix, antistatic agent, flame retardant and antioxidant are mixed and then melt-extruded and granulated in sequence to obtain nylon 66 functional masterbatch.

10. The application of the nylon 66 functional masterbatch according to any one of claims 1 to 8 or the nylon 66 functional masterbatch prepared by the preparation method according to claim 9 in an automotive fuel tank.

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