Polyamide composite material as well as preparation method and application thereof

Abstract

The invention discloses a polyamide composite material as well as a preparation method and application thereof, and belongs to the field of high polymer materials. According to the invention, a proper amount of montmorillonite is added into the polyamide composite material, and the adsorption and barrier effects of the montmorillonite are utilized, so that the migration and precipitation of molecules of a VCI (Volatile Corrosion Inhibitor) can be effectively slowed down, and the electrical insulation performance, especially the electrical insulation performance under high-temperature and high-humidity conditions, can be effectively maintained; montmorillonite not only can reduce the influence of VCI molecules on the performance of the flame retardant, but also can promote carbon formation during resin combustion, and can be used as a flame-retardant synergist to improve the flame-retardant effect of the flame retardant.

Description

Technical Field

[0001] This application relates to the field of polymer materials, and particularly relates to a polyamide composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Volatile Corrosion Inhibitor (abbreviated as VCI) is an active rust inhibitor that can penetrate everywhere and is volatile. It can be applied to various carriers, such as paper, plastic film, foam, lubricating oil, water, and organic solvents, to make corresponding volatile corrosion-inhibiting materials, such as volatile corrosion-inhibiting paper, volatile corrosion-inhibiting film, volatile corrosion-inhibiting foam, volatile corrosion-inhibiting oil, etc., to provide protection during the storage and transportation of metal parts. However, these volatile corrosion-inhibiting materials often need to be removed before the metal parts are put into normal use and cannot continue to provide protection during the use process. For products that contain both metal parts and plastic parts, if the volatile corrosion inhibitor is directly incorporated into the plastic parts, it is expected to continuously supplement the rust inhibitor on the surface of the metal parts enclosed or semi-enclosed by the plastic material during the use process, greatly reducing the rust risk of the metal. However, at present, the research on flame-retardant plastics for carrying VCI is less and the performance is insufficient, and mainly low-melting-point and heat-intolerant polyethylene is used. However, the electrical insulation of polyethylene will deteriorate significantly at high temperatures and is not suitable for applications in products with high requirements for flame retardancy, high temperature resistance, and electrical insulation.

[0003] Flame-retardant polyamide (PA) has excellent properties such as good flame retardancy, heat resistance, electrical properties, mechanical properties, toughness, oil resistance, wear resistance, self-lubrication, and chemical resistance. If a polyamide composite containing a flame retardant and a rust inhibitor is prepared, it is expected to prepare a plastic with insulation, flame retardancy, high temperature resistance, and volatile corrosion-inhibiting function suitable for use in the above application scenarios.

[0004] However, first, under high temperature and high humidity conditions, a large amount of the volatile corrosion inhibitor in the polyamide resin system is likely to precipitate, affecting the appearance and use. This is because the volatile corrosion inhibitor is a polar molecule, the polyamide resin is easy to absorb water, and water is the medium for the migration of polar molecules; high temperature will enhance the movement activity of the polymer chain, weakening its hindrance to the migration of polar molecules, so that the volatile corrosion inhibitor is easy to migrate and precipitate in the polyamide resin system under high temperature and high humidity conditions. Second, the volatile corrosion inhibitor will also deteriorate the flame retardant effect because its chemical properties are active, easy to thermally decompose and migrate and accumulate on the resin surface, conflicting with the flame retardant in the action mechanism. Third, polar groups of the volatile corrosion inhibitor, such as amino groups and carboxyl groups, are easy to ionize and are easy to migrate under an electric field, reducing the insulation resistance and increasing the leakage current, deteriorating the electrical insulation of the polyamide material. Summary of the Invention

[0005] Based on the deficiencies of the existing technology, the purpose of this application is to provide a polyamide composite material, its preparation method and application, so as to improve the problem of the precipitation of volatile corrosion inhibitors (VCI) while endowing the material with good VCI resistance, flame retardancy and electrical insulation properties.

[0006] To achieve the above object, in the first aspect, this application provides a polyamide composite material, which comprises the following components in parts by weight:

[0007]

[0008] Montmorillonite is a layered silicate clay mineral with a very large specific surface area. The surface and interlayer adsorption sites have an adsorption effect on cations, anions and organic molecules. Moreover, the layered structure of montmorillonite has a barrier effect, which can increase the path length of gas and liquid penetration, thereby reducing the gas permeability and moisture permeability of the material and hindering the migration of VCI molecules.

[0009] By adding an appropriate amount of montmorillonite to the polyamide composite material and utilizing its adsorption and barrier effects, the migration and precipitation of polar VCI molecules can be effectively slowed down, and the electrical insulation performance can be effectively maintained, especially under high temperature and high humidity conditions (such as 85°C, 85% RH). In addition, the adsorption effect of montmorillonite on VCI molecules and the carbon formation promotion effect during the combustion process can reduce the interference of chemically active VCI molecules on the flame retardant performance.

[0010] Under the combined action of the above-mentioned specific amounts of each component of the polyamide composite material, VCI molecules are not easily precipitated under high temperature and high humidity conditions, and the appearance is good. At the same time, it also has good VCI resistance, flame retardancy and electrical insulation properties (especially the electrical insulation properties under high temperature and high humidity such as 85°C, 85% RH), and is suitable for the preparation of electronic and electrical components, such as connectors, switches, sensors, capacitors, battery components, charging gun components, etc.

[0011] The polyamide resin is 29 to 96 parts by weight, such as 29 parts by weight, 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 55 parts by weight, 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 95 parts by weight, 96 parts by weight or the range formed by any two of the above values. Preferably, the weight percentage content of the polyamide resin in the polyamide composite material is more than 25%, such as 25%, 30%, 35%, 40%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 96% or the range formed by any two of the above values.

[0012] The glass fiber is 0 to 40 parts by weight, such as 0 part by weight, 5 parts by weight, 7 parts by weight, 10 parts by weight, 12 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, 30 parts by weight, 32 parts by weight, 34 parts by weight, 36 parts by weight, 38 parts by weight, 40 parts by weight or an interval range formed by any two of the above values.

[0013] The flame retardant is 3 to 30 parts by weight, such as 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 16 parts by weight, 18 parts by weight, 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, 30 parts by weight or an interval range formed by any two of the above values.

[0014] The vapor phase rust inhibitor is 0.5 to 5 parts by weight, such as 0.5 part by weight, 0.7 part by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.2 parts by weight, 3.4 parts by weight, 3.6 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.2 parts by weight, 4.4 parts by weight, 4.6 parts by weight, 4.8 parts by weight, 5 parts by weight or an interval range formed by any two of the above values.

[0015] The montmorillonite is 0.5 to 5 parts by weight, such as 0.5 part by weight, 0.7 part by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.2 parts by weight, 3.4 parts by weight, 3.6 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.2 parts by weight, 4.4 parts by weight, 4.6 parts by weight, 4.8 parts by weight, 5 parts by weight or an interval range formed by any two of the above values. Considering that too much montmorillonite will deteriorate the mechanical properties of the composite material, such as toughness (such as elongation at break, notch impact strength, etc.), therefore, it is necessary to control the amount of montmorillonite not exceeding 5 parts by weight.

[0016] The lubricant is 0 to 2 parts by weight, such as 0 part by weight, 0.3 part by weight, 0.5 part by weight, 0.7 part by weight, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight or an interval range formed by any two of the above values.

[0017] The antioxidant is 0 to 1 part by weight, such as 0 part by weight, 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight, 0.5 part by weight, 0.6 part by weight, 0.7 part by weight, 0.8 part by weight, 0.9 part by weight, 1 part by weight or the range formed by any two of the above values.

[0018] The acid absorbent is 0 to 1 part by weight, such as 0 part by weight, 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight, 0.5 part by weight, 0.6 part by weight, 0.7 part by weight, 0.8 part by weight, 0.9 part by weight, 1 part by weight or the range formed by any two of the above values.

[0019] Preferably, the mass of the montmorillonite is more than 0.2 times the mass of the volatile corrosion inhibitor. For example, the mass of the montmorillonite is 0.2 times, 0.5 times, 0.8 times, 1 time, 1.5 times, 2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times or the range formed by any two of the above values of the mass of the volatile corrosion inhibitor. Controlling the mass of the montmorillonite to be more than 0.2 times the mass of the volatile corrosion inhibitor can further improve the precipitation of the volatile corrosion inhibitor.

[0020] More preferably, the mass of the montmorillonite is 0.9 to 1.7 times the mass of the volatile corrosion inhibitor. When the dosage ratio of the montmorillonite to the volatile corrosion inhibitor is controlled within this specific range, it is more beneficial to balance the precipitation of the volatile corrosion inhibitor, the volatile corrosion inhibition performance and the electrical insulation performance, especially the electrical insulation performance under high temperature and high humidity conditions (such as the electrical insulation performance at 85°C and 85% RH).

[0021] Preferably, the dosage of the volatile corrosion inhibitor is 0.9 to 3.6 parts by weight, which is more beneficial to balance the precipitation of the volatile corrosion inhibitor, the volatile corrosion inhibition performance and the electrical insulation performance, especially the electrical insulation performance under high temperature and high humidity conditions (such as the electrical insulation performance at 85°C and 85% RH).

[0022] The montmorillonite can be selected from ordinary montmorillonite, organically modified montmorillonite, or a mixture of ordinary montmorillonite and organically modified montmorillonite. The ordinary montmorillonite can be selected from at least one of sodium-based montmorillonite, calcium-based montmorillonite, magnesium-based montmorillonite, and sodium-calcium-based montmorillonite.

[0023] Preferably, the montmorillonite is organically modified montmorillonite, and the organically modified montmorillonite is quaternary ammonium salt-modified montmorillonite. Quaternary ammonium salt modification can improve the dispersion of montmorillonite in PA, enable montmorillonite to play a better role, and thus make the precipitation and electrical insulation performance of the material, especially the electrical insulation performance under high temperature and high humidity conditions (such as 85°C and 85% RH), better.

[0024] More preferably, the quaternary ammonium salt contains at least one of an alkyl group with a hydroxyl group and an alkyl group with a carboxyl group, and the number of carbon atoms in the quaternary ammonium salt molecule is 10 to 50. Using the above specific quaternary ammonium salt to modify montmorillonite can form a hydrogen bond between montmorillonite and PA, improve the dispersibility of montmorillonite and the interfacial bonding force with PA resin, further improve the precipitation problem of the vapor-phase rust inhibitor, and further improve the electrical insulation performance of the material, especially the electrical insulation performance under high temperature and high humidity conditions (such as 85 °C, 85% RH).

[0025] Preferably, the average particle size of the montmorillonite is 1 to 50 μm.

[0026] The average particle size of the montmorillonite is measured by the following method: Weigh 0.5 g of montmorillonite, add it to 20 mL of absolute ethanol, then add 3 - 4 drops of the dispersant polyvinylpyrrolidone, ultrasonicate at 600 W for 30 min, then take 2 mL and drop it into a quartz cuvette, and measure Dv50 in a laser particle size analyzer to obtain the average particle size.

[0027] The vapor-phase rust inhibitor can be selected according to the type of metal to be protected. Exemplarily, the vapor-phase rust inhibitor includes at least one of nitrous acid, metal salts of nitrous acid, fatty acids, metal salts of fatty acids, aromatic acids, metal salts of aromatic acids, phytic acid, organic amines, salts of organic amines, and rust-preventive components for non-ferrous metals.

[0028] Among them, the fatty acid can be selected from at least one of aliphatic monocarboxylic acids with 4 - 12 carbon atoms and aliphatic dicarboxylic acids with 4 - 12 carbon atoms; the aromatic acid can be selected from at least one of benzoic acid, cinnamic acid, nitrobenzoic acid, methyl salicylic acid, salicylic acid, and tert-butylbenzoic acid; the organic amine can be selected from at least one of ethylenediamine, hexamethylenediamine, cyclohexylamine, dicyclohexylamine, diisopropylamine, benzylamine, monoethanolamine, diethanolamine, triethanolamine, n-butylamine, tributylamine, pentylamine, octadecylamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenetetramine (urotropine), morpholine, piperidine, and piperazine; the salts of the organic amine include at least one of hydrochlorides of organic amines, benzoates of organic amines, carbonates of organic amines, nitrites of organic amines, formates of organic amines, and acetates of organic amines. The rust-preventive components for non-ferrous metals can be selected to include metal salts of heterocyclic compounds, alkaline earth metal salts of heterocyclic compounds, and zinc salts of heterocyclic compounds, where the heterocyclic compounds all include at least one of benzotriazole, methylbenzotriazole, 2-mercaptobenzothiazole, 2-benzothiazolylthioacetic acid, 3-(2-benzothiazolylthio)propionic acid, and 2,4,6-trimercapto-s-triazine.

[0029] Preferably, the vapor-phase rust inhibitor is selected from at least one of sodium nitrite, sodium benzoate, cyclohexylamine carbonate, dicyclohexylamine nitrite, benzotriazole, and monoethanolamine benzoate.

[0030] Preferably, the relative viscosity of the polyamide is 1.8 to 4. For example, the relative viscosity of the polyamide is 1.8, 2.2, 2.6, 3.0, 3.4, 3.7, 4.0 or any range formed by any two of the above values.

[0031] The relative viscosity of the polyamide resin is measured according to Standard ISO 307:2007. The measurement is carried out in 98 wt.% concentrated sulfuric acid at 25 ± 0.01 °C to measure the relative viscosity of the polyamide with a concentration of 0.25 g / dL.

[0032] The polyamide is selected from at least one of ring-opening polymers of lactams with 3 or more rings, polycondensates of ω-amino acids, and polycondensates of dicarboxylic acids and diamines. Among them, the dicarboxylic acid can be selected from at least one of aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids; the diamine can be selected from at least one of aliphatic diamines, alicyclic diamines, and aromatic diamines.

[0033] Exemplarily, the lactam includes at least one of ε-caprolactam, heptanamide, α-pyrrolidone, 2-piperidone; the ω-amino acid polymer includes at least one of aminohexanoic acid, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid; the dicarboxylic acid includes at least one of adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, sodium 5-sulfoisophthalate, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, cyclohexanedicarboxylic acid; the diamine includes at least one of tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, m-xylylenediamine, p-xylylenediamine, 2-methylpentamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, aminoethylpiperazine.

[0034] Preferably, the polyamide includes at least one of polyamide 4, polyamide 6, polyamide 7, polyamide 8, polyamide 11, polyamide 12, polyamide 46, polyamide 56, polyamide 66, polyamide 69, polyamide 410, polyamide 510, polyamide 610, polyamide 611, polyamide 612, polyamide 66 / 6T copolymer, polyamide 6 / 66 copolymer, polyamide 6 / 12 copolymer, polyamide 6 / 6T copolymer, polyamide 6T / 6I copolymer, polyamide MXD6, polyamide MXD10.

[0035] Preferably, the flame retardant includes at least one of aluminum diethyl phosphinate, melamine cyanurate, melamine polyphosphate, and red phosphorus.

[0036] Preferably, the glass fiber is one or a combination of E glass fiber, H glass fiber, R glass fiber, S glass fiber, D glass fiber, and C glass fiber. More preferably, the glass fiber is E glass fiber.

[0037] Preferably, the glass fiber is an alkali-free chopped glass fiber with an average diameter of 9 - 13 μm and an average length of 3 - 4.5 mm.

[0038] The average diameter and average length of the glass fiber can be measured by the following method: obtaining an image of the glass fiber through an optical microscope, then using image analysis software to identify and measure the fibers in the image, calculating the diameter and length of each fiber, and statistically obtaining the average diameter and length.

[0039] Preferably, the lubricant includes at least one of silicone, montan ester lubricants, and pentaerythritol esters.

[0040] Preferably, the antioxidant includes at least one of hindered phenol antioxidants, hindered amine antioxidants, thioester antioxidants, and phosphite antioxidants.

[0041] Preferably, the acid absorbent includes at least one of zinc oxide, magnesium oxide, aluminum oxide, and zirconium oxide.

[0042] The polyamide composite material may further contain at least one of a nucleating agent and a color powder. The dosage of the nucleating agent can be selected from 0 - 3 parts by weight, and the dosage of the color powder can be selected from 0 - 3 parts by weight.

[0043] Exemplarily, the nucleating agent can be selected from at least one of aliphatic carboxylate salts, aliphatic carboxylate calcium salts, and calcium carbonate.

[0044] Exemplarily, the color powder can be selected from at least one of aniline black, ultramarine blue, and titanium yellow.

[0045] Preferably, the ratio of the mass of the vapor phase rust inhibitor to the total mass of the polyamide resin and the glass fiber is 1:(10 - 180), such as 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, 1:110, 1:120, 1:130, 1:140, 1:150, 1:160, 1:170, 1:180, or any range formed by any two of the above values.

[0046] In a second aspect, the present application provides a method for preparing the polyamide composite material, comprising the following steps:

[0047] Mix all the raw materials, melt and extrude, draw into strands, cool, pelletize, and dry to obtain the polyamide composite material.

[0048] Preferably, the melt extrusion is carried out in a twin-screw extruder.

[0049] Preferably, the glass fiber is added from a side feeding hopper.

[0050] Preferably, the ratio of the length to the diameter of the twin-screw extruder is (36 - 48):1, the screw rotation speed is 200 - 600 r / min, and the melt extrusion temperature is 160 - 260 °C.

[0051] In a third aspect, the present application further provides a plastic part made of the polyamide composite material, and the plastic part is used in combination with a metal during use. Since the plastic part is made of the polyamide composite material, it can realize its own function and provide rust protection for the metal part.

[0052] During use, the plastic part can be in direct contact with the metal, indirect contact, or non-contact, as long as the volatile corrosion inhibitor in the plastic part can protect the metal.

[0053] Preferably, the plastic part is a plastic part of an electronic and electrical component.

[0054] Preferably, the electronic and electrical components include at least one of a connector, a switch, a power adapter, a sensor, a micro motor, an inverter, a driver, a capacitor, a battery assembly, and a charging gun assembly. For example, the polyamide composite material can be used to prepare the housing of a connector.

[0055] Compared with the prior art, the beneficial effects of the present application are as follows:

[0056] (1) By adding an appropriate amount of montmorillonite to the polyamide composite material in the present application, and utilizing its adsorption and barrier effects, the migration and precipitation of VCI molecules can be effectively slowed down, and the electrical insulation performance can be effectively maintained, especially the electrical insulation performance under high temperature and high humidity conditions (such as 85 °C, 85% RH). In addition, montmorillonite can not only reduce the influence of VCI molecules on the flame retardant performance, but also promote carbon formation during resin combustion, and can be used as a flame retardant synergist to improve the flame retardant effect of the flame retardant.

[0057] (2) Under the combined action of the components in the specific amounts of the polyamide composite material of this application, VCI molecules are not easily precipitated under high-temperature and high-humidity conditions, and the appearance is good. At the same time, it also has good gas-phase rust prevention, flame retardancy, and electrical insulation properties (especially the electrical insulation properties under high-temperature and high-humidity conditions such as 85°C and 85% RH), and is suitable for the preparation of electronic and electrical components, such as connectors, switches, power adapters, sensors, micro-motors, frequency converters, drivers, capacitors, battery modules, charging gun modules, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a schematic diagram of sample assembly in the gas-phase rust prevention performance and VCI precipitation test. Among them, 1 is a square hollow box made by splicing after injection molding of the polyamide composite material, 21 is the first round hole, 22 is the second round hole, 3 is a steel sheet, and 4 is a glass round sheet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0059] In order to better illustrate the purpose, technical solutions, and advantages of this application, the following will further illustrate this application in combination with specific examples and comparative examples. The purpose is to understand the content of this application in detail, rather than to limit this application. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of this application. The experimental reagents and instruments involved in the implementation of this application are all common ordinary reagents and instruments unless otherwise specified. In this application, for the technical features described in an open-ended manner, it includes both a closed technical solution composed of the listed features and an open technical solution including the listed features.

[0060] The following examples and comparative examples all provide a polyamide composite material. The formulations of these polyamide composite materials are shown in Tables 1 and 2, and their preparation methods include the following steps:

[0061] Weigh various raw materials according to the ratios in Tables 1-2, and mix and disperse the raw materials except glass fiber (if any) to obtain a premix;

[0062] Add the obtained premix to the main feeding hopper of the twin-screw extruder, and add glass fiber (if any) to the side feeding hopper of the sixth section of the barrel. The screw speed of the twin-screw extruder is 400 rpm, the length-diameter ratio of the screw is 40:1, the temperatures of each section of the barrel are 160°C, 250°C, 240°C, 240°C, 220°C, 220°C, 220°C, 230°C, 230°C respectively, and the head temperature is 250°C. Melt and extrude, draw into strips, cool, pelletize, and dry to obtain the polyamide composite material.

[0063] The raw material information used in the above examples and comparative examples is as follows, and unless otherwise specified, they are all commercially available raw materials. In addition, the component raw materials used in each parallel experiment are the same:

[0064] (1) PA

[0065] PA66: Grade PA66 EPR24, relative viscosity 2.37, purchased from China Pingdingshan Shenma Engineering Plastics Co., Ltd.;

[0066] PA6: Grade HY - 2500A, relative viscosity 2.45, purchased from Jiangsu Haiyang Chemical Fiber Co., Ltd., China.

[0067] (2) Glass fiber

[0068] Glass fiber: Grade: ECS10 - 03 - 568H, purchased from China National Bluestar (Group) Co., Ltd.

[0069] (3) Flame retardant

[0070] Red phosphorus: Grade FR9950T, red phosphorus masterbatch with nylon resin as the carrier, phosphorus content 52 wt.%, purchased from Xinde New Materials Co., Ltd., Tongcheng, China;

[0071] Aluminum diethylphosphinate: Grade OP 1230, purchased from Clariant Corporation;

[0072] Melamine polyphosphate: Grade BUDIT 3141, purchased from Budenheim Iberica, Germany;

[0073] Melamine cyanurate: Grade MCA - 35, purchased from Shandong Haiwang Chemical Industry Co., Ltd.

[0074] (4) Vapor phase rust inhibitor

[0075] Vapor phase rust inhibitor 1: A mixture of sodium benzoate, benzotriazole and dicyclohexylamine nitrite, with a mass ratio of 1:1:1 for the three components;

[0076] Vapor phase rust inhibitor 2: A mixture of sodium nitrite, cyclohexylamine carbonate, benzotriazole and monoethanolamine benzoate, with a mass ratio of 2:1:1:1 for the four components;

[0077] Vapor phase rust inhibitor 3: Monoethanolamine benzoate;

[0078] Sodium benzoate (product number S104124), benzotriazole (product number B101002), sodium nitrite (product number S111972) and dicyclohexylamine nitrite (product number D109081) were all purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Cyclohexylamine carbonate (product number C966137) was purchased from Macklin; Monoethanolamine benzoate was purchased from Suzhou Senfeida Chemical Co., Ltd.

[0079] (5) Montmorillonite

[0080] Ordinary montmorillonite: average particle size of 2 μm, obtained by grinding and sieving XFI44 PGW from Xianfeng Nano Materials Technology Co., Ltd., Jiangsu, China;

[0081] Organically modified montmorillonite 1: quaternary ammonium salt modified montmorillonite (where the quaternary ammonium salt has 18 carbon atoms and contains an alkyl group with a carboxyl group), average particle size of 2 μm, obtained by grinding and sieving I.24TL from Nanocor Inc., USA;

[0082] Organically modified montmorillonite 2: quaternary ammonium salt modified montmorillonite (where the quaternary ammonium salt has 22 carbon atoms and contains an alkyl group with a hydroxyl group), average particle size of 1.9 μm, obtained by grinding and sieving I.34TCN from Nanocor Inc., USA;

[0083] Organically modified montmorillonite 3: quaternary ammonium salt modified montmorillonite (where the quaternary ammonium salt has 22 carbon atoms and contains an alkyl group with a hydroxyl group), average particle size of 18 μm, obtained by grinding and sieving I.34TCN from Nanocor Inc., USA.

[0084] (6) Hydrotalcite

[0085] Hydrotalcite: average particle size of 2 μm, grade D200, purchased from Hefei Anyuhe New Materials Technology Co., Ltd.

[0086] (7) Auxiliary agents

[0087] Lubricant: silicone, commercially available;

[0088] Antioxidant: hindered phenol antioxidant, N,N’-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), commercially available;

[0089] Acid absorbent: zinc oxide, commercially available.

[0090] The following performance tests were carried out on the polyamide composites of the above examples and comparative examples:

[0091] (1) Vapor phase rust prevention performance and precipitation of vapor phase rust inhibitor: After injection molding, the polyamide composite materials were spliced to form a square hollow box 1 (length×width×height 100 mm×70 mm×30 mm, wall thickness 1.5 mm, with asymmetric first round holes 21 and second round holes 22 with a diameter of 4 mm on the front and back surfaces of the box (the center point of the first round hole 21 is 20 mm from the bottom, the center point of the second round hole 22 is 10 mm from the bottom, and the shortest distance from the center of these two round holes to the nearest vertical side of their respective surfaces is 10 mm, facilitating gas exchange inside and outside the box), in accordance with Figure 1Assemble as shown. Place a 10 - steel sheet 3 with dimensions 50mm * 50mm * 3mm flat on the inner bottom of the box. The steel sheet is padded by two glass round sheets 4 with a thickness of 5mm so that the steel sheet has no direct contact with the box. Place the sample to be tested in a damp - heat aging chamber and conduct an alternating damp - heat test in accordance with GB / T 2423.4 - 2008: 6 hours at 25°C and 98% RH, 3 - hour heating stage from 25°C to 55°C at 95% RH, 9 hours at 55°C and 93% RH, and 6 - hour cooling stage from 55°C to 25°C at 98% RH. One cycle is 24 hours, and the cycle is repeated 9 times, for a total of 216h. After the damp - heat test, after returning to room temperature for 24h, open the test sample, take out the steel sheet and observe its rusting condition. According to the ratio R (R = A / A0) of the rusted area (A) on the upper surface of the steel sheet to the total upper - surface area (A0), it is divided into severe rust (R > 20%), moderate rust (5% < R ≤ 20%), slight rust (0.5% ≤ R ≤ 5%), and no rust (R < 0.5%). If the test result is moderate rust, slight rust, or no rust, it is judged qualified; at the same time, observe the precipitation of the volatile corrosion inhibitor on the surface of the test - sample box, and evaluate the precipitation degree according to whether it is visible to the naked eye and the average value (D) of the longest diameter of the precipitated particles, which is divided into severe precipitation (visible to the naked eye, D ≥ 0.2mm), slight precipitation (visible to the naked eye, 0.1 ≤ D < 0.2mm), minor precipitation (visible to the naked eye, D < 0.1mm), and no precipitation (invisible to the naked eye). If the test result is slight precipitation, minor precipitation, or no precipitation, it is judged qualified;

[0092] (2) Flame - retardant performance: Inject the polyamide composite material into a standard spline with a thickness of 0.8mm, and conduct a vertical - burning flame - retardant performance test on the spline according to the UL94 - 2013 standard;

[0093] (3) Insulation - resistance test: Prepare a square plate with a thickness of 1mm according to the IEC 62631 - 3 - 2:2023 standard and test the insulation resistivity after being placed at 85°C and 85% RH for 1000h, that is, obtain the insulation resistivity after 1000h of double 85 damp - heat aging.

[0094] The test results are shown in Tables 1 and 2.

[0095] Table 1

[0096]

[0097] Table 2

[0098]

[0099]

[0100] As can be seen from the above data, the polyamide composite materials in the embodiments of the present application have good balance in gas-phase rust prevention performance, precipitation of gas-phase rust inhibitors, flame retardancy, and insulation resistance. For example, the precipitation of gas-phase rust inhibitors is small, slight, or none; the gas-phase rust prevention grade is moderate rust, slight rust, or no rust; the flame retardancy grade is V-0; and the insulation resistivity is above 0.2 GΩ after 1000 h of double 85 damp heat aging.

[0101] In Comparative Example 1, no gas-phase rust inhibitor and montmorillonite were added, and the gas-phase rust prevention effect was very poor. In Comparative Example 2, no montmorillonite was added, resulting in easy precipitation of the gas-phase rust inhibitor, poor flame retardancy performance, and low insulation resistivity after 1000 h of double 85 damp heat aging. In Comparative Example 3, hydrotalcite was used to replace montmorillonite, and the precipitation of the gas-phase rust inhibitor was severe.

[0102] Compared with Example 4, in Examples 1-2, due to the use of organically modified montmorillonite, the precipitation of the gas-phase rust inhibitor was further improved, and the insulation resistivity was further increased after 1000 h of double 85 damp heat aging.

[0103] Comparing Examples 1, 9-12, it can be seen that when the mass of montmorillonite is in the range of 0.9-1.7 times the mass of the gas-phase rust inhibitor, it is more conducive to balancing the precipitation of the gas-phase rust inhibitor, gas-phase rust prevention performance, and electrical insulation performance under high temperature and high humidity conditions.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A polyamide composite material, characterized in that: Contains the following components by weight:

2. The polyamide composite material according to claim 1, characterized in that: The mass of the montmorillonite is more than 0.2 times the mass of the vapor phase rust inhibitor; preferably, the mass of the montmorillonite is 0.9 to 1.7 times the mass of the vapor phase rust inhibitor.

3. The polyamide composite material according to claim 1, characterized in that: The amount of the vapor phase rust inhibitor is 0.9 to 3.6 parts by weight.

4. The polyamide composite material according to claim 1, characterized in that: The montmorillonite is an organic modified montmorillonite, and the organic modified montmorillonite is a quaternary ammonium salt modified montmorillonite.

5. The polyamide composite material according to claim 4, characterized in that: The quaternary ammonium salt contains at least one of an alkyl group with a hydroxyl group and an alkyl group with a carboxyl group, and the number of carbon atoms in the quaternary ammonium salt molecule is 10 to 50.

6. The polyamide composite material according to claim 1, characterized in that: The vapor phase rust inhibitor includes at least one of nitrous acid, metal salts of nitrous acid, fatty acids, metal salts of fatty acids, aromatic acids, metal salts of aromatic acids, phytic acid, organic amines, organic amine salts, and rust-proof components for non-ferrous metals. The rust-proof components for non-ferrous metals include metal salts of heterocyclic compounds, alkaline earth metal salts of heterocyclic compounds, and zinc salts of heterocyclic compounds. The heterocyclic compounds include at least one of benzotriazole, methylbenzotriazole, 2-mercaptobenzothiazole, 2-benzothiazolylthioacetic acid, 3-(2-benzothiazolylthio)propionic acid, and 2,4,6-trimercapto-s-triazine.

7. The polyamide composite material according to claim 1, characterized in that: At least one of the following conditions is met: S1. The relative viscosity of the polyamide is 1.8 to 4; S2. The polyamide includes at least one of polyamide 4, polyamide 6, polyamide 7, polyamide 8, polyamide 11, polyamide 12, polyamide 46, polyamide 56, polyamide 66, polyamide 69, polyamide 410, polyamide 510, polyamide 610, polyamide 611, polyamide 612, polyamide 66 / 6T copolymer, polyamide 6 / 66 copolymer, polyamide 6 / 12 copolymer, polyamide 6 / 6T copolymer, polyamide 6T / 6I copolymer, polyamide MXD6, and polyamide MXD10; S3. The flame retardant comprises at least one of diethyl aluminum phosphinate, melamine cyanurate, melamine polyphosphate and red phosphorus; S4. The lubricant comprises at least one of silicone, montan ester lubricant, and pentaerythritol ester; S5. The antioxidant comprises at least one of a hindered phenol antioxidant, a hindered amine antioxidant, a thioester antioxidant, and a phosphite antioxidant; S6. The acid absorber comprises at least one of zinc oxide, magnesium oxide, aluminum oxide and zirconium oxide; S7. The ratio of the mass of the vapor phase rust inhibitor to the total mass of the polyamide resin and the glass fiber is 1:(10-180).

8. The method for preparing a polyamide composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: All raw materials are mixed, melt-extruded, drawn into strips, cooled, pelletized, and dried to obtain a polyamide composite material.

9. A plastic component made of the polyamide composite material according to any one of claims 1 to 7, wherein the plastic component is used in combination with a metal.

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