Polyamide composite and use thereof

Abstract

The application provides a polyamide composite material and application thereof, and the polyamide composite material comprises the following components in parts by mass: 35-82 parts of a polyamide resin, 5-45 parts of a reinforcing material, and 5-25 parts of an organic phosphonate flame retardant; the water-soluble acid value of the organic phosphonate flame retardant is 0.1-0.3 mg KOH / g. By using the organic phosphonate flame retardant with a low acid value, the application can slow down the decomposition of dialkyl phosphinic acid in the high-temperature process, so that the amount of mold dirt generated in the injection molding process of the polyamide composite material is obviously reduced, thereby improving the injection molding production efficiency; meanwhile, the polyamide composite material has a significantly reduced water boiling leachate content, excellent wet heat resistance, and a prolonged service life under a wet heat condition.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polymer materials, and particularly relates to a polyamide composite material and application thereof. BACKGROUND

[0002] Polyamide, also known as nylon, has a repeating amide group -NHCO- in the molecular backbone. The group has polarity, which forms strong hydrogen bonding between molecular chains. Therefore, polyamide has high crystallinity and excellent mechanical properties, and is a kind of resin with the largest output, the most varieties, the most extensive application and excellent comprehensive performance among the five general engineering plastics.

[0003] Traditional flame-retardant nylon usually uses bromine-based flame retardant. However, with the increasing environmental protection requirements and the release of the ROHS directive of the European Union on limiting and prohibiting the use of toxic substances and the WEEE directive on handling waste electronic equipment, the traditional bromine-based flame retardant cannot meet the requirements of the ROHS and WEEE directives of the European Union. Halogen-free flame-retardant nylon material conforms to the development trend of green environmental protection and is also a development trend requirement of flame-retardant nylon material in the electronic and electrical industries. In the application field of electronic and electrical materials, such as in the field of circuit breakers, connectors and wiring terminals, the material is required to be halogen-free, and more and more customers not only have requirements on the flame-retardant grade of the material, but also put forward higher and higher requirements on the outgassing property and service life of the material.

[0004] As a general halogen-free flame retardant, dialkyl phosphinic acid salt not only has good flame-retardant performance, small addition amount, small influence on the physical properties and electrical properties of the base resin, but also has smaller smoke emission than halogen-based flame retardants when burning, high CTI (relative tracking index), and excellent performance in mechanical properties and electrical properties. Dialkyl phosphinic acid salt flame-retardant polyamide is more and more favored by manufacturers in the electrical industry, and has a broad market prospect. However, with the continuous improvement of the performance requirements of the industry, the performance defects of dialkyl phosphinic acid salt flame-retardant polyamide have gradually been exposed. Because polyamide has many polar amide groups, it is easy to absorb water and has a high water absorption rate. For example, the water absorption rate of polyamide 66 under the condition of 23℃ and 50% humidity can reach 2.7%. The addition of dialkyl phosphinic acid salt aggravates the water absorption problem of the material. In addition, Braun U et al. found that when dialkyl phosphinic acid salt is used to flame-retardant polyamide, dialkyl phosphinic acid salt is easily decomposed by heat during extrusion processing or injection molding high-temperature processing, generates acidic dialkyl phosphinic acid, and further promotes the decomposition of the system, resulting in large gas during processing. Serious mold fouling often occurs on the mold during repeated injection molding, which not only affects the appearance of the product, but also requires frequent cleaning of the mold, resulting in low production efficiency and making it difficult for the product to be well promoted and used.

[0005] The main method to solve the problem of mold fouling in the injection molding of dialkyl phosphinic acid salt flame-retardant polyamide materials at present is to add an acid absorber to the system to reduce the acidity of the system. For example, EP2417191A1 reduces the acidity of the system by adding calcium oxide to the system, which reacts with acidic substances to reduce the decomposition of the base resin and the corrosiveness to the mold during high-temperature injection molding; however, calcium oxide is prone to moisture absorption, and after being added, it will exacerbate the moisture absorption problem of the polyamide system, resulting in an increase in water absorption, which is difficult to control during processing. CN112409786A prepared a halogen-free flame-retardant thermoplastic polyamide with low mold fouling by adding a certain amount of ethylene copolymer to the system. CN114874616A prepared a halogen-free flame-retardant thermoplastic polyamide with more continuous mold opening and closing times (lower mold fouling) by adding metal oxides and polyhydroxy systems to the system. However, the above methods of improving the acidity of the system and reducing mold fouling by adding external additives not only increase the cost, but also cannot avoid the problem of performance degradation of the flame-retardant polyamide caused by the addition of new substances, such as poor compatibility between the external additive and the base resin, mechanical property reduction of the material caused by the addition of inorganic additives, high risk of additive precipitation, and insufficient humidity and heat stability of the product.

[0006] Therefore, it is a research focus in the field to develop a flame-retardant polyamide material that can achieve low mold fouling, low additive precipitation, and good humidity and heat resistance without the aid of other additives. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a polyamide composite material and its application, by using a low-acid-value organic phosphonate flame retardant, the mold fouling amount of the polyamide composite material is greatly reduced, the water boiling precipitate content is low, the humidity and heat resistance is good, and the service life under humid and hot conditions is prolonged.

[0008] To achieve this purpose, the present application adopts the following technical solutions:

[0009] In a first aspect, the present application provides a polyamide composite material, which comprises the following components by mass fraction:

[0010] Polyamide resin 35-82 parts

[0011] Reinforcing material 5-45 parts

[0012] Organic phosphonate flame retardant 5-25 parts

[0013] The water-soluble acid value of the organic phosphonate flame retardant is 0.1-0.3 mg KOH / g.

[0014] The polyamide composite material of the present application adopts low-acid-value organic phosphonate flame retardant, can slow down the decomposition of dialkyl phosphinic acid in high temperature process, makes the amount of mold dirt generated in the injection molding process of the polyamide composite material small without adding other acid-absorbing / adsorbing auxiliary agents, thereby improving the injection molding production efficiency and improving the appearance of the product; meanwhile, the polyamide composite material has significantly reduced water boiling precipitate content (i.e. less release of flame retardant), good wet heat stability, and prolongs the service life under wet heat conditions.

[0015] The following is a preferred technical solution of the present application, but is not a limitation on the technical solutions provided by the present application. Through the following preferred technical solution, the purpose and beneficial effects of the present application can be better achieved and realized.

[0016] In the polyamide composite material of the present application, the mass fraction of the polyamide resin is 35-82 parts, for example, it can be 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts or 80 parts, and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0017] The mass fraction of the reinforcing material is 5-45 parts, for example, it can be 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts or 44 parts, and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0018] The mass fraction of the organic phosphonate flame retardant is 5-25 parts, for example, it can be 6 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts or 24 parts, and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0019] The water-soluble acid value of the organic phosphonate flame retardant is 0.1-0.3 mg KOH / g, for example, it can be 0.11 mg KOH / g, 0.12 mg KOH / g, 0.15 mg KOH / g, 0.18 mg KOH / g, 0.2 mg KOH / g, 0.22 mg KOH / g, 0.25 mg KOH / g, 0.28 mg KOH / g or 0.29 mg KOH / g, and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0020] Exemplarily, the water-soluble acid value of the organic phosphonate flame retardant can be tested by the following method: 1g of the sample to be tested is uniformly moistened with ethanol (the mass of ethanol is m 乙醇 ), then water (the mass of water is m 水 ) is added, and after boiling at 90℃ for 1h, the solution is cooled to 25℃ and kept at this temperature for 30min, and then the ethanol aqueous solution is added to the total mass before boiling; filtration is performed, and the mass of the clear filtrate is m1, the test acid value of the clear filtrate is measured by the potentiometric titration method, and the blank acid value of (m 水 +m 乙醇 ) is measured by the potentiometric titration method, wherein the concentration of the potassium hydroxide solution used for titration is 0.05mol / L, and the water-soluble acid value = test acid value × (m 水 +m 乙醇 ) / m1-blank acid value.

[0021] In the present application, the polyamide includes any one or a combination of at least two of the condensation product of a dicarboxylic acid and a diamine, the condensation product of an omega-amino acid, and the ring-opening polymerization product of a cyclic lactam. Exemplarily, the dicarboxylic acid includes but is not limited to any one or a combination of at least two of adipic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, terephthalic acid, isophthalic acid. Exemplarily, the diamine includes but is not limited to any one or a combination of at least two of butanediamine, pentanediamine, hexanediamine, octanediamine, nonanediamine, decanediamine, dodecanediamine, p-phenylenediamine, m-phenylenediamine. Exemplarily, the cyclic lactam includes but is not limited to any one or a combination of at least two of caprolactam, caprylolactam, undecanolactam, dodecanolactam. Exemplarily, the omega-amino acid includes but is not limited to any one or a combination of at least two of the omega-amino acid formed by ring-opening of the aforementioned cyclic lactam, aminobenzoic acid.

[0022] Preferably, the polyamide resin includes any one or a combination of at least two of polyamide 6 (polycaprolactam), polyamide 11 (polyundecanolactam), polyamide 12 (polydodecanolactam), polyamide 66 (polyhexanediamine adipate), polyamide 46 (polyhexanediamine succinate), polyamide 610 (polydecanediamine sebacate), polyamide 611 (polydecanediamine undecanoate), polyamide 612 (polydecanediamine dodecanoate), polyamide 1010 (polydecanediamine sebacate), polyamide 6T (polyhexanediamine terephthalate), polyamide 9T (polynonanediamine terephthalate), polyamide 10T (polydecanediamine terephthalate).

[0023] Preferably, the reinforcing material includes any one or a combination of at least two of glass fiber, carbon fiber, polyaramid fiber, asbestos fiber, wollastonite fiber, ceramic fiber, potassium titanate whisker, basic magnesium sulfate whisker, silicon carbide whisker, aluminum borate whisker, and further preferably glass fiber.

[0024] Preferably, the glass fiber comprises any one of or a combination of at least two of an E-glass fiber, a C-glass fiber, an A-glass fiber, an AR-glass fiber, an S-glass fiber, a D-glass fiber, and a quartz glass fiber.

[0025] Preferably, the diameter of the glass fiber is 0.1-30 μm, for example, can be 0.5 μm, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, or 28 μm, and specific point values between the above-mentioned point values, the present application does not exhaustively list the specific point values included in the range for the sake of brevity and conciseness, and is further preferably 5-20 μm.

[0026] Preferably, the organic phosphonate salt flame retardant comprises the following components in parts by mass:

[0027]

[0028] The parts by mass of the diethyl phosphinate in the organic phosphonate salt flame retardant is 95-99.88 parts, for example, can be 95.5 parts, 96 parts, 96.2 parts, 96.5 parts, 96.8 parts, 96.9 parts, 97 parts, 97.2 parts, 97.5 parts, 97.8 parts, 98 parts, 98.2 parts, 98.5 parts, 98.8 parts, 99 parts, 99.2 parts, 99.5 parts, 99.6 parts, or 99.8 parts, and specific point values between the above-mentioned point values, the present application does not exhaustively list the specific point values included in the range for the sake of brevity and conciseness.

[0029] Preferably, the mass percentage content of diethyl phosphinate in the organic phosphonate salt flame retardant is ≥94%, for example, can be 94.5%, 95%, 95.5%, 96%, 96.2%, 96.5%, 96.8%, 97%, 97.2%, 97.5%, 97.8%, 98%, 98.2%, 98.5%, 98.8%, 99%, 99.2%, 99.5%, 99.8%, or 99.8%, and specific point values between the above-mentioned point values, the present application does not exhaustively list the specific point values included in the range for the sake of brevity and conciseness.

[0030] The mass fraction of ethyl butyl phosphinate in the organic phosphonate flame retardant is 0.1-3 parts, for example, it can be 0.12 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.7 parts, 2.8 parts, or 2.9 parts, and specific point values between the above point values, limited to the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0031] The mass fraction of ethyl phosphinate in the organic phosphonate flame retardant is 0.01-1 parts, for example, it can be 0.02 parts, 0.05 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, or 0.95 parts, and specific point values between the above point values, limited to the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0032] The mass fraction of ethyl phosphinate in the organic phosphonate flame retardant is 0.01-1 parts, for example, it can be 0.02 parts, 0.05 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, or 0.95 parts, and specific point values between the above point values, limited to the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0033] Exemplarily, the mass fraction of diethyl phosphinate, diethyl phosphinate, ethyl phosphinate, monoethyl phosphinate in the organic phosphonate flame retardant can be obtained by liquid chromatography analysis test, for example, the sample to be tested is dissolved with 5 times the mass of sulfuric acid aqueous solution (mass concentration 30%), and then diluted 10-30 times with mobile phase for analysis test; the mobile phase uses a mixture of water and methanol with a mass ratio of 9:1, and 0.5% trifluoroacetic acid by volume is added, a ShimNex CS C18 chromatographic column is used, and the flow rate is 0.6 mL / min; the mass content of each component is calculated by area normalization method.

[0034] Preferably, the cations in the diethyl phosphinate, ethyl butyl phosphinate, ethyl phosphinate, monoethyl phosphinate are each independently selected from Al 3+ , Ca 2+ , Cu 2+ , Zn 2+ , Fe2+ , Fe 3+ , Ti 4+ , further preferably Al 3+ .

[0035] Preferably, the organic phosphonate flame retardant further comprises alkali insoluble substance, the alkali insoluble substance comprises any one or a combination of at least two of hydroxide, oxide, phosphate, pyrophosphate, polyphosphate, phosphite.

[0036] Preferably, the alkali insoluble substance comprises any one or a combination of at least two of aluminum hydroxide, aluminum oxide, aluminum phosphate, aluminum pyrophosphate, aluminum polyphosphate, aluminum phosphite.

[0037] Preferably, the mass fraction of the alkali insoluble substance in the organic phosphonate flame retardant is ≤3 parts, for example, it can be 0, 0.01, 0.02, 0.05, 0.08, 0.1, 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, or 2.8 parts, and specific point values between the above point values, limited by the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0038] Illustratively, the mass fraction of the alkali insoluble substance in the organic phosphonate flame retardant is tested by the following method: the sample to be tested is mixed with sodium hydroxide aqueous solution (mass concentration 3%) at a mass ratio of 1:100, stirred at 35°C for 30 min, filtered with filter paper with a precision of ≤2 μm, and washed with water for 3 times, the filter paper is dried and weighed, the mass increase value of the filter paper after filtration (dry filter paper) is the insoluble mass, and the ratio of the insoluble mass to the mass of the sample to be tested is the mass content of the alkali insoluble substance.

[0039] Preferably, the organic phosphonate flame retardant further comprises other phosphorus-containing compounds, the mass fraction of the other phosphorus-containing compounds in the organic phosphonate flame retardant is ≤1 part, for example, it can be 0, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 0.95 parts, and specific point values between the above point values, limited by the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range, further preferably 0.05-0.4 parts.

[0040] It should be noted that the other phosphorus-containing compounds are alkali-soluble and different from diethyl phosphinate, ethyl butyl phosphinate, ethyl phosphinate, monoethyl phosphinate, and the mass fraction of the other phosphorus-containing compounds can be measured by nuclear magnetic resonance spectroscopy. In the nuclear magnetic resonance spectrum, the integral area of the peak other than diethyl phosphinate, ethyl butyl phosphinate, ethyl phosphinate, and monoethyl phosphinate represents the content of the other phosphorus-containing compounds.

[0041] Preferably, the organic phosphonate flame retardant has an organic acid value of ≤0.05 mg KOH / g, for example, 0.001 mg KOH / g, 0.005 mg KOH / g, 0.008 mg KOH / g, 0.01 mg KOH / g, 0.02 mg KOH / g, 0.025 mg KOH / g, 0.028 mg KOH / g, 0.03 mg KOH / g, 0.032 mg KOH / g, 0.035 mg KOH / g, 0.038 mg KOH / g, 0.04 mg KOH / g, or 0.045 mg KOH / g, and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application does not list the specific point values included in the range, and further preferably 0.001-0.04 mg KOH / g.

[0042] Illustratively, the organic phosphonate flame retardant has an organic acid value that can be tested by the following method: 1 g of the sample to be tested is uniformly wetted with dichloromethane (the mass of dichloromethane is m 二氯甲烷 ), and then boiled at 90°C for 1 h in a sealed state, cooled to 25°C and kept at a constant temperature for 30 min, and then supplemented with dichloromethane to the total mass before boiling; filtered to obtain a clear filtrate with a mass of m 二氯甲烷 1, the clear filtrate is tested for the test acid value by the potentiometric titration method, the blank acid value is tested by the potentiometric titration method, the concentration of the potassium hydroxide solution used for titration is 0.05 mol / L, and the organic acid value = test acid value x m 二氯甲烷 / m1-blank acid value.

[0043] Preferably, the mass content of sulfate in the organic phosphonate flame retardant is 100-500 ppm, for example, 120 ppm, 150 ppm, 200 ppm, 250 ppm, 270 ppm, 300 ppm, 350 ppm, 400 ppm, 420 ppm, 450 ppm, or 480 ppm, and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application does not list the specific point values included in the range, and further preferably 110-430 ppm.

[0044] Exemplarily, the mass content of sulfate in the organic phosphonate flame retardant is tested by the method in the standard EN 14582:2007-“Determination of halogen content” using ion chromatography technology, and is obtained by external standard method.

[0045] Preferably, the D50 of the organic phosphonate flame retardant is 1-100 pm, for example, it can be 10 pm, 20 pm, 30 pm, 33 pm, 35 pm, 38 pm, 40 pm, 50 pm, 60 pm, 70 pm, 80 pm, 90 pm, or 95 pm, and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application does not list the specific point values included in the range any more, and further preferably, it is 20-60 pm. 50 The particle size is the particle size corresponding to the cumulative volume distribution percentage of 50%, which can be determined by the standard GB / T 19077-2016 particle size distribution laser diffraction method using a laser particle size analyzer.

[0046] Preferably, the D50 of the organic phosphonate flame retardant is 1-100 pm, for example, it can be 10 pm, 20 pm, 30 pm, 33 pm, 35 pm, 38 pm, 40 pm, 50 pm, 60 pm, 70 pm, 80 pm, 90 pm, or 95 pm, and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application does not list the specific point values included in the range any more, and further preferably, it is 20-60 pm. 50 The particle size is the particle size corresponding to the cumulative volume distribution percentage of 50%, which can be determined by the standard GB / T 19077-2016 particle size distribution laser diffraction method using a laser particle size analyzer.

[0047] Preferably, the water content of the organic phosphonate flame retardant is ≤1 wt%, for example, it can be 0, 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, or 0.9 wt%, and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application does not list the specific point values included in the range any more, and further preferably, it is 0.05-0.3 wt%.

[0048] Exemplarily, the water content of the organic phosphonate flame retardant can be tested by an infrared moisture analyzer, for example, using a MA 35 infrared moisture analyzer of Sartorius, Germany, and the water content is automatically tested after the sample is placed at 120°C for 30 min.

[0049] Preferably, the phosphorus content of the organic phosphonate flame retardant is 22-25 wt%, for example, it can be 22.2 wt%, 22.5 wt%, 22.8 wt%, 23 wt%, 23.2 wt%, 23.5 wt%, 23.8 wt%, 24 wt%, 24.2 wt%, 24.5 wt%, or 24.8 wt%, and specific point values between the above point values. Due to the limitation of the length and the consideration of simplicity, the present application does not list the specific point values included in the range any more.

[0050] Illustratively, the phosphorus content of the organic phosphonate flame retardant can be tested by dissolving the sample to be tested with aqueous sulfuric acid (mass concentration 30%), and testing according to the standard GB / T 11893-1989 "Determination of total phosphorus in water - Ammonium molybdate spectrophotometric method".

[0051] It should be noted that the polymer composition of the present application can also include any other additives, other auxiliary agents, etc. that are motivated to be added in the art.

[0052] Preferably, the polyamide composite further includes 1-15 parts by mass of a melamine flame retardant, the parts by mass of the melamine flame retardant can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, or 14 parts, and specific point values between the above point values, limited to the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0053] Preferably, the melamine flame retardant includes any one or a combination of at least two of melamine polyphosphate, melamine pyrophosphate, piperazine pyrophosphate, melam polyphosphate, melam pyrophosphate, melam phosphate, melam diethyl phosphinate, melam ethyl phosphinate, melam phosphite, melam alkyl phosphonate.

[0054] Preferably, the mass ratio of the organic phosphonate flame retardant to the melamine flame retardant is 1:(0.1-3), for example, it can be 1:0.2, 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, etc., and further preferably 1:(0.2-1).

[0055] Preferably, the polyamide composite further includes any one or a combination of at least two of a synergistic flame retardant, an antioxidant, a lubricant.

[0056] Preferably, the synergistic flame retardant includes any one or a combination of at least two of zinc borate, zinc stannate, zinc sulfide, boehmite.

[0057] Preferably, the parts by mass of the synergistic flame retardant in the polyamide composite is ≤5 parts, the synergistic flame retardant can be 0, 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, or 4.5 parts, and specific point values between the above point values, limited to the length and for the sake of simplicity, the present application will not exhaustively list the specific point values included in the range.

[0058] Preferably, the polyamide composite further comprises 0.01-1 parts by mass of an antioxidant, which can be 0.05 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, or 0.9 parts by mass, and specific point values between the aforementioned point values, the specific point values included in the range not being exhaustively listed due to the limitation of the length and for the sake of brevity.

[0059] Preferably, the antioxidant comprises any one or a combination of at least two of a hindered amine antioxidant, a hindered phenol antioxidant, a phosphite antioxidant, and a thioester antioxidant.

[0060] Exemplarily, the antioxidant includes any one of or a combination of at least two of tetra-β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid pentaerythritol ester, n-octadecyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexylenediamine, tris(2,4-di-tert-butylphenyl)phosphite, 2,6-di-tert-butyl-p-cresol, distearyl-β,β-thiodipropionate, 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,6-di-tert-butyl-4-methoxyphenol, tocopherols, 2,2'-thiobis(6-tert-butyl-4-methylphenol), 2,2'-thiobis(4-octylphenol), 4,4'-thiobis(6-tert-butyl-3-methylphenol), 4,4'-thiobis(6-tert-butyl-2-methylphenol), 4,4'-thiobis(3,6-di-sec-amylphenol), 4,4'-bis(2,6-di-methyl-4-hydroxyphenyl)di-sulfide, 2,2-methylenebis(6-tert-butyl-4-methylphenol, 3,5,3',5'-tetra-tert-butyl-4,4'-dihydroxydibenzyl ether, bis(2,6-di-tert-butyl-4-hydroxy-methylphenyl)carbonate, 2,2-bis(3,5-di-tert-butyl-2-hydroxybenzyl)propanediol dicaprylate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol, 2,4-bis-octylmercapto-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine, dimethyl-2,5-di-tert-butyl-4-hydroxybenzylphosphonate, 4-hydroxylauramide, 4-hydroxystearanilide, octyl-N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate, β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid ester, β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid ester, 3,5-di-tert-butyl-4-hydroxyphenylacetic acid ester, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine.

[0061] Preferably, the polyamide composite further includes 0.01-1 parts by mass of a lubricant, which can be 0.05 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, or 0.9 parts by mass, and specific point values between the above point values, the specific point values included in the range are not exhaustively listed in the present disclosure due to the limitation of the length and the consideration of simplicity.

[0062] Preferably, the lubricant comprises any one or a combination of at least two of an ester-based lubricant, an alcohol-based lubricant, a hydrocarbon-based lubricant, a fatty acid-based lubricant, a fatty acid amide-based lubricant, a metal soap-based lubricant.

[0063] Preferably, the polyamide composite further comprises any one or a combination of at least two of a filler, a colorant, an ultraviolet light absorber.

[0064] Preferably, the filler comprises any one or a combination of at least two of silicon dioxide, aluminum silicate, silicon oxide, calcium carbonate, titanium oxide, talc, wollastonite, diatomite, clay, kaolin, glass spheres, mica, gypsum, iron oxide, magnesium oxide, zinc oxide.

[0065] Preferably, the colorant comprises an inorganic colorant and / or an organic colorant; the colorant can comprise a pigment and / or a dye depending on its solubility and coloring properties.

[0066] Illustratively, the colorant comprises any one or a combination of at least two of titanium dioxide, ultramarine blue, iron oxide, zinc sulfide, carbon black, phthalocyanine, quinacridone, perylene black, aniline black.

[0067] Preferably, the ultraviolet light absorber comprises any one or a combination of at least two of a hydroxybenzoic acid ester-based ultraviolet light absorber, a benzophenone-based ultraviolet light absorber, a benzotriazole-based ultraviolet light absorber, a substituted acrylonitrile-based ultraviolet light absorber, a triazine-based ultraviolet light absorber, a hindered amine-based ultraviolet light absorber.

[0068] Exemplarily, the ultraviolet absorber includes any one or a combination of at least two of 3,5-diisobutyl-4-hydroxybenzoic acid hexadecyl ester, 3,5-di-tert-butyl-4-hydroxybenzoic acid-2,4-di-tert-butylphenyl ester, 3,5-di-tert-butyl-4-hydroxybenzoic acid n-hexadecyl ester, 2-hydroxy-4-alkyloxybenzophenone, 1,3-bis(methoxy-3-hydroxy-4-benzophenone)benzene, 2-hydroxy-4-phenylalkyloxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-hydroxy-4-methyl methacrylate benzophenone, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-methyl)-benzotriazole, 2-(3',5'-di-tert-butyl-2'-hydroxy)-benzotriazole, 2-(2'-hydroxy-3'-isobutyl-5'-tert-butyl)-benzotriazole, 2-(2'-hydroxy-3',5'-bis(1,1-dimethylphenyl)-benzotriazole, 2-(2'-hydroxy-5'-tert-octyl)-benzotriazole, 2-(2'-hydroxy-3'-(1,1-dimethylphenyl)-5'-(1,1,3,3-tetramethylbutyl)-benzotriazole, 2,2'-methylene-(6-(2H-benzotriazole)-4-tert-octyl)phenol, 2-(2H-benzotriazole-2)-4,6-di(1-methyl-1-phenylethyl)phenol, decanedioic acid bis 2,2,6,6-tetramethylpiperidinol ester, N,N'-(2,2,6,6-tetramethyl-4-aminopiperidine)-isophthalamide, decanedioic acid bis 1-octyloxy-2,2,6,6-tetramethylpiperidinol ester, and methyl methacrylate (1,2,2,6,6-pentamethylpiperidinol) ester.

[0069] Preferably, the mass fraction of the filler in the polyamide composite is ≤40 parts, for example, can be 0, 0.1, 0.5, 1, 2, 5, 8, 10, 15, 20, 25, 30, 35 or 38 parts, and specific point values between the above-mentioned point values, limited to the length and for the sake of simplicity, the present application does not exhaustively list the specific point values included in the range.

[0070] In a preferred technical solution, the polyamide composite includes the following components in mass parts:

[0071]

[0072] The polyamide resin is a base material, and preferably, the mass percentage of the polyamide resin in the polyamide composite is 35%-82%, for example, can be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, and specific point values between the above-mentioned point values, limited to the length and for the sake of simplicity, the present application does not exhaustively list the specific point values included in the range.

[0073] The reinforcing material can adjust the mechanical properties of the polyamide composite material, and achieve the reinforcing effect. Preferably, the mass percentage of the reinforcing material in the polyamide composite material is 5% to 45%, for example, it can be 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, or 44%, and specific point values between the above point values. Due to the limitation of length and the consideration of simplicity, the present application will not list the specific point values included in the range.

[0074] Preferably, the mass percentage of the organic phosphonate flame retardant in the polyamide composite material is 5% to 25%, for example, it can be 6%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, or 34%, and specific point values between the above point values. Due to the limitation of length and the consideration of simplicity, the present application will not list the specific point values included in the range.

[0075] Preferably, the water boiling phosphorus content of the polyamide composite material is ≤510 ppm, for example, it can be 360 ppm, 380 ppm, 400 ppm, 420 ppm, 450 ppm, 480 ppm, 500 ppm, 505 ppm, or 508 ppm, and specific point values between the above point values. Due to the limitation of length and the consideration of simplicity, the present application will not list the specific point values included in the range, and further preferably 370-507 ppm.

[0076] Illustratively, the water boiling phosphorus content of the polyamide composite material is tested by the following method: the polyamide composite material to be tested is boiled in hot water at 90°C for 1h, cooled to room temperature, filtered, and the filtrate is measured for phosphorus content by the method of GB / T 11893-1989 ammonium molybdate spectrophotometry.

[0077] Preferably, the injection molding dirt of the polyamide composite material is ≤7.5 mg, for example, it can be 3.5 mg, 3.8 mg, 4 mg, 4.2 mg, 4.5 mg, 4.8 mg, 5 mg, 5.2 mg, 5.5 mg, 5.8 mg, 6 mg, 6.2 mg, 6.5 mg, 6.8 mg, 7 mg, 7.2 mg, or 7.4 mg, and specific point values between the above point values. Due to the limitation of length and the consideration of simplicity, the present application will not list the specific point values included in the range, and further preferably 4-7.2 mg.

[0078] Illustratively, the injection molding dirt of the polyamide composite material is tested by the following method: the polyamide composite material is continuously injected at an injection temperature of 290°C, 285°C, 280°C, or 260°C for 150 molds, the dirt sample in the last collected mold is taken out and weighed to obtain the mass of the injection molding dirt.

[0079] In a second aspect, the present application provides a method for preparing the polyamide composite material according to the first aspect, the method comprising: melt blending the polyamide resin, the reinforcing material and the organic phosphonate flame retardant, and then extruding to obtain the polyamide composite material.

[0080] Preferably, the method comprises the following steps:

[0081] mixing the polyamide resin and the organic phosphonate flame retardant to obtain a premix;

[0082] melt blending the premix and the reinforcing material, and then extruding to obtain the polyamide composite material;

[0083] Preferably, the mixed material further comprises any one or a combination of at least two of melamine flame retardant, synergistic flame retardant, antioxidant, lubricant.

[0084] Preferably, the melt blending is performed in a screw extruder.

[0085] Preferably, the screw extruder is a twin-screw extruder.

[0086] Preferably, the temperature of the screw extruder is 180-330℃, for example, it can be 190℃, 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, 310℃ or 320℃, and specific point values between the above point values, limited to the length and for the sake of simplicity, the present application does not exhaustively list the specific point values included in the range.

[0087] Preferably, the extrusion further comprises the steps of granulation and drying.

[0088] In a third aspect, the present application provides the use of the polyamide composite material according to the first aspect in electronic and electrical products, parts of electrical products, energy storage devices, connectors or automobile parts.

[0089] Preferably, the polyamide composite material is used in plug-in connectors, power supply components in power distribution devices, circuit boards, potting materials, power plugs, safety switches, lampshades, LED housings, capacitor housings, coil tubes, fans, protective contacts, cables, circuit boards, charger connecting lines, engine cover plates, fabric coatings, vehicle seats, connector housings, circuit breaker housings, contactor housings or electromagnetic switches.

[0090] Compared with the prior art, the present application has the following beneficial effects:

[0091] The polyamide composite provided by the present application can slow down the generation of dialkyl phosphinic acid in the high-temperature process by using the organic phosphonate flame retardant with low acid value, so that the amount of mold dirt generated in the injection molding process of the polyamide composite is obviously reduced, thereby improving the injection molding production efficiency and improving the appearance of the product. Meanwhile, the polyamide composite has a significantly reduced water boiling leachate content, excellent wet heat stability, and a prolonged service life under wet heat conditions. DETAILED DESCRIPTION

[0092] The technical solutions of the present application are further illustrated by specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0093] In one specific embodiment, the preparation method of the organic phosphonate flame retardant includes the following method I or method II.

[0094] The method I includes the following steps:

[0095] (A1) free radical reaction of a hypophosphite aqueous solution and an antioxidant with ethylene in the presence of an initiator to obtain a diethyl hypophosphite aqueous solution;

[0096] (A2) mixing the diethyl hypophosphite aqueous solution obtained in step (A1), a metal salt aqueous solution and a lye, and performing reaction under the condition of pH value of 3.5-3.8 to obtain a diethyl hypophosphite metal salt slurry;

[0097] (A3) mixing the diethyl hypophosphite metal salt slurry obtained in step (A2) and a flocculating agent, and stirring to obtain diethyl hypophosphite metal salt flocculates; filtering, washing and drying the diethyl hypophosphite metal salt flocculates to obtain the organic phosphonate flame retardant.

[0098] The method II includes the following steps:

[0099] (B1) free radical reaction of a hypophosphite aqueous solution and an antioxidant with ethylene in the presence of an initiator to obtain a diethyl hypophosphite aqueous solution;

[0100] (B2) reaction of the diethyl hypophosphite aqueous solution obtained in step (B1), sulfuric acid and metal hydroxide, and then adding a lye to obtain a diethyl hypophosphite salt slurry with pH value of 3.8-4.2;

[0101] (B3) mixing the diethyl hypophosphite salt slurry obtained in step (B2) and a flocculating agent, and stirring to obtain diethyl hypophosphite salt flocculates; filtering, washing and drying the diethyl hypophosphite salt flocculates to obtain the organic phosphonate flame retardant.

[0102] In the specific embodiment of the present application, the preparation method of the organic phosphonate flame retardant is designed. Through the design of antioxidant, flocculating agent and other materials, the design of process steps and pH process parameters and the joint action, the low-acid-value organic phosphonate flame retardant is prepared. When used in a polyamide composite, it can reduce the mold dirt and make the polyamide composite have a lower water boiling precipitate content, greatly improving the hygrothermal stability and service life under hygrothermal conditions.

[0103] In a preferred specific embodiment, the antioxidant of step (A1), step (B1) each independently includes any one or a combination of at least two of hindered phenolic antioxidants, hindered amine antioxidants, phosphite antioxidants, thioester antioxidants, preferably any one or a combination of at least two of hindered phenolic antioxidants, phosphite antioxidants, thioester antioxidants.

[0104] In a preferred specific embodiment, the antioxidant of step (A1), step (B1) each independently includes any one or a combination of at least two of hindered phenolic antioxidants, hindered amine antioxidants, phosphite antioxidants, thioester antioxidants, preferably any one or a combination of at least two of hindered phenolic antioxidants, phosphite antioxidants, thioester antioxidants.

[0105] The antioxidant can be a single component, such as any one of the above-listed antioxidants, or a plurality of compounded composite antioxidants, such as a combination of hindered phenolic antioxidants and phosphite antioxidants, a typical combination being a compounded antioxidant of antioxidant 1010 and antioxidant 168 in different proportions, such as antioxidant 215, antioxidant 225, etc.

[0106] In a preferred specific embodiment, the initiator of step (A1), step (B1) each independently includes any one or a combination of at least two of organic peroxide, persulfate, azo initiator, photoinitiator.

[0107] In a preferred embodiment, the organic peroxide comprises any one of diisobutyryl peroxide, benzoyl peroxide, bis(2-ethylhexyl)peroxydicarbonate, diisopropyl peroxydicarbonate, 1,1,3,3-tetramethylbutylperoxy pivalate, t-butyl peroxy pivalate, t-amyl peroxy pivalate, dilauroyl peroxide, di(3,3,5-trimethylacetyl)peroxide, 2,5-dimethyl-2,5-di(2-ethylacetylperoxy)hexane, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, t-amyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy isobutyrate, 1,1-di-t-butyl peroxy-3,3,5-trimethylcyclohexane, 1,1-di-t-amyl peroxy cyclohexane, 1,1-di-t-butyl peroxy cyclohexane, di-t-butyl peroxide, di-t-amyl peroxide, dicumyl peroxide, 2,5-di-t-butyl peroxy-2,5-dimethylhexane, t-butyl peroxy acetate, t-amyl peroxy benzoate, t-butyl peroxy maleate, t-butyl peroxy-2-ethylhexyl carbonate, or a combination of at least two thereof.

[0108] In a preferred embodiment, the persulfate salt comprises any one of sodium persulfate, potassium persulfate, ammonium persulfate, or a combination of at least two thereof.

[0109] In a preferred embodiment, the azo initiator comprises any one of azobis isobutyronitrile, azobis isohexylnitrile, azobis isobutyramidine hydrochloride, azobis isobutylimidazole hydrochloride, azoisobutyryl cyanamide, or a combination of at least two thereof.

[0110] It is to be understood that the present application does not have any particular limitation on the specific selection of the photoinitiator, and any photoinitiator commonly used in the art is suitable.

[0111] In a preferred embodiment, the flocculant of step (A3) and step (B3) each independently comprises any one of a polyacrylamide flocculant, a starch flocculant, a chitin flocculant, or a combination of at least two thereof, more preferably a polyacrylamide flocculant, and further preferably an anionic polyacrylamide and / or a non-ionic polyacrylamide.

[0112] In method I, the hypophosphite salt preferably comprises sodium hypophosphite and / or potassium hypophosphite, thereby obtaining an aqueous solution of sodium diethyl hypophosphite and / or potassium diethyl hypophosphite.

[0113] It is to be understood that the hypophosphite salt can be anhydrous hypophosphite salt and / or a hypophosphite salt hydrate.

[0114] In a preferred embodiment, the hypophosphorous acid salt is sodium hypophosphite, and step (A1) results in an aqueous solution of sodium diethylphosphinate.

[0115] In a preferred embodiment, the mass percentage of the hypophosphorous acid salt in the aqueous solution of the hypophosphorous acid salt in step (A1) is 10-60%, such as 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% or 55%, and further preferably 30-40%.

[0116] In a preferred embodiment, the mass ratio of the hypophosphorous acid salt to the antioxidant in step (A1) is 100:(0.02-1.2), such as 100:0.04, 100:0.05, 100:0.06, 100:0.08, 100:0.1, 100:0.2, 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9, 100:0.95, 100:1, 100:1.05, 100:1.1 or 100:1.15, and further preferably 100:(0.05-1).

[0117] In a preferred embodiment, the mass ratio of the hypophosphorous acid salt to the initiator in step (A1) is 100:(0.1-5), such as 100:0.2, 100:0.5, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5 or 100:4.8.

[0118] It should be noted that the initiator in step (A1) can be added at once, in batches or continuously during the reaction, and that a part of the initiator in step (A1) can be added beforehand and the rest continuously during the reaction.

[0119] In a preferred embodiment, the molar ratio of ethylene to the hypophosphorous acid salt in step (A1) is (2-2.1):1, such as 2.01:1, 2.02:1, 2.04:1, 2.05:1, 2.06:1, 2.08:1 or 2.09:1.

[0120] In a preferred embodiment, the free radical reaction in step (A1) is carried out in a protective atmosphere.

[0121] In a preferred embodiment, the protective atmosphere comprises a nitrogen atmosphere and / or an argon atmosphere.

[0122] In a preferred embodiment, the temperature of the radical reaction in step (A1) is 70-120°C, for example, it can be 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C or 115°C, and the like, more preferably 80-110°C, and further preferably 90-105°C.

[0123] The radical reaction in step (A1) is carried out in the presence of an initiator. When the pressure of the reaction system is substantially unchanged, it is considered that the reaction is complete, and the reaction is stopped.

[0124] In a preferred embodiment, the time of the radical reaction in step (A1) is 2-16h, for example, it can be 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h or 15h, and the like.

[0125] In the present application, the metal salt in step (A2) is a water-soluble metal salt. Preferably, the metal salt comprises a metal sulfate and / or a metal chloride, and more preferably a metal sulfate.

[0126] In a preferred embodiment, the metal in the metal salt in step (A2) comprises any one or a combination of at least two of Al, Ca, Cu, Zn, Fe and Ti, and further preferably Al.

[0127] In a preferred embodiment, the metal salt in step (A2) comprises aluminum sulfate.

[0128] It should be noted that the metal salt can be anhydrous metal salt and / or metal salt hydrate.

[0129] In a preferred embodiment, the mass percentage of the metal salt in the aqueous solution of the metal salt in step (A2) is 20-40%, for example, it can be 22%, 25%, 28%, 30%, 32%, 35% or 38%, and the like.

[0130] In a preferred embodiment, the molar ratio of the metal salt to the diethylphosphinic acid salt in step (A2) is 1:(5.8-6.2), for example, it can be 1:5.82, 1:5.85, 1:5.88, 1:5.9, 1:5.92, 1:5.95, 1:5.98, 1:6, 1:6.02, 1:6.05, 1:6.08, 1:6.1, 1:6.12, 1:6.15 or 1:6.18, and the like, and further preferably 1:6.

[0131] In one embodiment, the pH of the reaction system in step (A2) is 3.5-3.8, for example, it can be 3.52, 3.55, 3.58, 3.6, 3.62, 3.65, 3.68, 3.7, 3.72, 3.75 or 3.78, etc.

[0132] In one preferred embodiment, the base solution in step (A2) comprises a sodium hydroxide solution and / or a potassium hydroxide solution.

[0133] The present application does not have any special restrictions on the mass concentration of the sodium hydroxide solution and the potassium hydroxide solution, as long as the sodium hydroxide solution and / or the potassium hydroxide solution is added to maintain the pH of the reaction system obtained in step (A2) at 3.5-3.8.

[0134] In one preferred embodiment, the temperature of the reaction in step (A2) is 20-80°C, for example, it can be 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C or 75°C, etc., and is further preferably 40-60°C.

[0135] In one preferred embodiment, the reaction time in step (A2) is 0.1-5h, for example, it can be 0.2h, 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h, 2h, 2.2h, 2.5h, 2.8h, 3h, 3.2h, 3.5h, 3.8h, 4h or 4.5h, etc.

[0136] It should be noted that in step (A2), the aqueous metal salt solution and the base solution are simultaneously added to the aqueous diethylphosphinic acid salt solution for reaction, or the aqueous metal salt solution, the base solution and the aqueous diethylphosphinic acid salt solution are continuously added to a reaction device (such as a stirred reaction kettle, a static mixer, a dynamic mixer) at a constant flow rate for sufficient mixing and reaction. When the aqueous metal salt solution and the base solution are simultaneously added to the aqueous diethylphosphinic acid salt solution for reaction, the reaction temperature is 20-80°C, preferably 30-70°C, and further preferably 40-60°C, the dropping time of the aqueous metal salt solution and the base solution is 0.1-5h (for example, 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, etc.), preferably 0.5-3h, and further preferably 1h-3h; when the aqueous metal salt solution, the base solution and the aqueous diethylphosphinic acid salt solution are continuously added to the reaction vessel at a constant flow rate, the reaction temperature is 40-80°C, preferably 50-60°C, and the reaction space velocity is 0.1-2 / h (for example, 0.2 / h, 0.5 / h, 0.8 / h, 1 / h, 1.2 / h, 1.5 / h, 1.8 / h, etc.), preferably 0.3-1 / h, and further preferably 0.5-0.8 / h.

[0137] In a preferred embodiment, the mass of the flocculant in step (A3) is 0.01-0.5%, for example, it can be 0.02%, 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25%, 0.28%, 0.3%, 0.32%, 0.35%, 0.38%, 0.4%, 0.42%, 0.45%, or 0.48%, etc., based on 100% of the theoretical mass of the metal diethylphosphinate salt.

[0138] The "theoretical mass of the metal diethylphosphinate salt" is calculated based on the amounts of diethylphosphinic acid salt and metal salt in step (A2).

[0139] In a preferred embodiment, the flocculant and water can be mixed at 20-30°C for 10-20 min to obtain a flocculant solution, and then the flocculant solution is mixed with the metal diethylphosphinate salt slurry and stirred. The mass ratio of the flocculant to water is 1:(10-1000), for example, it can be 1:50, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900, or 1:950, etc.

[0140] In a preferred embodiment, the temperature of the mixing in step (A3) is 40-60°C, for example, it can be 42°C, 44°C, 46°C, 48°C, 50°C, 52°C, 54°C, 56°C, or 58°C, etc.

[0141] In a preferred embodiment, the number of washing in step (A3) is ≥4, for example, it can be 5, 6, 7, 8, 9, 10, or 12, etc., and further preferably 5-10. The diethylphosphinate salt flocculate is filtered and washed multiple times, which can better remove impurities and acidic substances in the product, and obtain the organic phosphonate flame retardant with low acid value.

[0142] Preferably, the washing reagent used in the washing is water.

[0143] Preferably, the mass ratio of water to solid in each of the washings is independently (1-10):1, for example, it can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, etc., and further preferably (1.5-6):1. The solid is the solid product obtained by filtration.

[0144] Preferably, the temperature of the drying in step (A3) is 105-250°C, for example, it can be 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 180°C, 200°C, 220°C or 240°C, and specific point values between the above-mentioned point values, for the sake of brevity and simplicity, the present application does not list the specific point values included in the range, and further preferably 110-150°C.

[0145] In a preferred embodiment, the method I specifically comprises the following steps:

[0146] (A1) in a protective atmosphere, a hypophosphite aqueous solution and an antioxidant are subjected to a free radical reaction with ethylene in the presence of an initiator to obtain a diethyl hypophosphite aqueous solution;

[0147] wherein the mass percentage of hypophosphite in the hypophosphite aqueous solution is 10-60%, the mass ratio of hypophosphite, antioxidant and initiator is 100:(0.02-1.2):(0.1-5); the temperature of the free radical reaction is 70-120°C, and the reaction is terminated when the pressure of the system no longer changes;

[0148] (A2) the diethyl hypophosphite aqueous solution, a metal salt aqueous solution and a lye are mixed, and a reaction is carried out at a pH value of 3.5-3.8 and a temperature of 40-60°C to obtain a diethyl hypophosphite metal salt slurry;

[0149] wherein the molar ratio of the metal salt to diethyl hypophosphite is 1:(5.9-6.1), and the mass percentage of the metal salt in the metal salt aqueous solution is 20-40%;

[0150] (A3) the diethyl hypophosphite metal salt slurry and a flocculant solution are mixed at a temperature of 40-60°C, and a diethyl hypophosphite salt flocculate is obtained by stirring; the diethyl hypophosphite salt flocculate is filtered, washed ≥4 times, and dried to obtain the organic phosphonate flame retardant;

[0151] wherein, based on 100% of the theoretical mass of the diethyl hypophosphite metal salt, the mass of the flocculant is 0.01-0.5%.

[0152] In a preferred embodiment, the mass percentage of hypophosphorous acid in the hypophosphorous acid aqueous solution in step (B1) is 20-70%, for example, it can be 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% or 65%, and further preferably 45-55%.

[0153] In a preferred embodiment, the mass ratio of hypophosphorous acid to antioxidant in step (B1) is 100:(0.02-1.2), for example, it can be 100:0.04, 100:0.05, 100:0.06, 100:0.08, 100:0.1, 100:0.2, 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9, 100:0.95, 100:1, 100:1.05, 100:1.1, or 100:1.15, and the like, and further preferably 100:(0.05-1).

[0154] In a preferred embodiment, the mass ratio of hypophosphorous acid to initiator in step (B1) is 100:(0.1-5), for example, it can be 100:0.2, 100:0.5, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, or 100:4.8, and the like.

[0155] It should be noted that the initiator in step (B1) of the present application can be added at one time, in batches, or continuously during the reaction; and a part of the initiator in step (B1) can be added in advance, and the remaining part can be continuously added during the reaction.

[0156] In a preferred embodiment, the molar ratio of ethylene to hypophosphorous acid in step (B1) is (2-2.1):1, for example, it can be 2.01:1, 2.02:1, 2.04:1, 2.05:1, 2.06:1, 2.08:1, or 2.09:1, and the like.

[0157] In a preferred embodiment, the free radical reaction in step (B1) is carried out in a protective atmosphere.

[0158] In a preferred embodiment, the protective atmosphere includes a nitrogen atmosphere and / or an argon atmosphere.

[0159] In a preferred embodiment, the temperature of the free radical reaction in step (B1) is 60-105°C, for example, it can be 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, or 98°C, and the like, more preferably 70-100°C, and further preferably 75-95°C.

[0160] The free radical reaction in step (B1) is carried out in the presence of an initiator, and when the pressure of the reaction system no longer changes substantially, it is considered that the reaction is complete, and the reaction is stopped.

[0161] In a preferred embodiment, the time of the radical reaction of step (B1) is 2-16 h, for example it can be 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h or 15 h, etc.

[0162] In a preferred embodiment, the metal hydroxide of step (B2) comprises any one of aluminum hydroxide, calcium hydroxide, copper hydroxide, zinc hydroxide, iron hydroxide, titanium hydroxide or a combination of at least two thereof, more preferably aluminum hydroxide.

[0163] In a preferred embodiment, the iron hydroxide comprises ferrous hydroxide and / or ferric hydroxide.

[0164] By employing the above metal hydroxide, the cation in the diethylphosphinic acid salt obtained in step (B2) comprises any one of Al, Ca, Cu, Zn, Fe or Ti, more preferably Al.

[0165] In a preferred embodiment, in step (B2), the molar amount of the metal hydroxide is 30-50 mol% based on 100% of the molar amount of the diethylphosphinic acid, for example it can be 32 mol%, 33 mol%, 33.3 mol%, 34 mol%, 35 mol%, 36 mol%, 38 mol%, 40 mol%, 42 mol%, 45 mol% or 48 mol%, etc.

[0166] In a preferred embodiment, in step (B2), the molar amount of the sulfuric acid is 5-50 mol% based on 100% of the molar amount of the diethylphosphinic acid, for example it can be 8 mol%, 10 mol%, 12 mol%, 15 mol%, 18 mol%, 20 mol%, 22 mol%, 25 mol%, 28 mol%, 30 mol%, 32 mol%, 35 mol%, 38 mol%, 40 mol%, 42 mol%, 45 mol% or 48 mol%, etc., further preferably 8-30 mol%, more preferably 10-15 mol%.

[0167] In a preferred embodiment, the temperature of the reaction of step (B2) is 70-150 °C, for example it can be 75 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C or 145 °C, etc., further preferably 80-120 °C, more preferably 90-100 °C.

[0168] Preferably, the time of the reaction of step (B2) is 2-12 h, for example it can be 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h or 11.5 h, etc.

[0169] In the present application, the pH value of the diethylphosphinic acid salt slurry in step (B2) is 3.8-4.2, for example, it can be 3.82, 3.85, 3.88, 3.9, 3.92, 3.95, 3.98, 4, 4.02, 4.05, 4.08, 4.1, 4.12, 4.15 or 4.18, etc.

[0170] In a preferred embodiment, the alkali solution in step (B2) comprises sodium hydroxide solution and / or potassium hydroxide solution.

[0171] The present application does not have any special restrictions on the mass concentration of sodium hydroxide solution and potassium hydroxide solution, as long as sodium hydroxide solution and / or potassium hydroxide solution is added to maintain the pH of the diethylphosphinic acid salt slurry obtained in step (B2) at 3.8-4.2.

[0172] In a preferred embodiment, in step (B3), the mass of the flocculant is 0.01-0.5% based on 100% of the theoretical mass of the diethylphosphinic acid salt, for example, it can be 0.02%, 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25%, 0.28%, 0.3%, 0.32%, 0.35%, 0.38%, 0.4%, 0.42%, 0.45% or 0.48%, etc.

[0173] wherein the "theoretical mass of diethylphosphinic acid salt" is calculated from the input amount of diethylphosphinic acid and metal hydroxide in step (B2).

[0174] In a preferred embodiment, the flocculant can be first mixed with water at 20-30°C for 10-20 min to obtain a flocculant solution, and then the flocculant solution is mixed with the diethylphosphinic acid salt slurry and stirred. The mass ratio of flocculant to water is 1:10-1000, for example, it can be 1:50, 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900 or 1:950, etc.

[0175] In a preferred embodiment, the temperature of the mixing in step (B3) is 40-60°C, for example, it can be 42°C, 44°C, 46°C, 48°C, 50°C, 52°C, 54°C, 56°C or 58°C, etc.

[0176] In a preferred embodiment, the number of washing in step (B3) is ≥4 times, for example, it can be 5 times, 6 times, 7 times, 8 times, 9 times, 10 times or 12 times, etc., and further preferably 5-10 times.

[0177] Preferably, the washing reagent used in the washing is water.

[0178] Preferably, the mass ratio of water to solid in each of the washings is independently (1-10):1, for example, it can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, etc., and further preferably (1.5-6):1. The solid is the solid product obtained by filtration.

[0179] Preferably, the temperature of the drying in step (B3) is 105-250℃, for example, it can be 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 180℃, 200℃, 220℃, or 240℃, and specific point values between the above-mentioned point values, limited by the length and for the sake of simplicity, the present application does not enumerate the specific point values included in the range, and further preferably 110-150℃.

[0180] In a preferred embodiment, the method II specifically comprises the following steps:

[0181] (B1) under a protective atmosphere, a hypophosphorous acid aqueous solution and an antioxidant are subjected to a free radical reaction with ethylene under the action of an initiator to obtain a diethyl hypophosphite aqueous solution;

[0182] wherein the mass concentration of the hypophosphorous acid aqueous solution is 20-70%, the mass ratio of hypophosphorous acid, antioxidant, and initiator is 100:(0.02-1.2):(0.1-5); the temperature of the free radical reaction is 60-100℃, and the reaction is terminated when the pressure of the system no longer changes;

[0183] (B2) the diethyl hypophosphite aqueous solution, sulfuric acid, and metal hydroxide are reacted at 70-150℃ for 2-12h, and then a lye is added to make the pH of the system 3.8-4.2 to obtain a diethyl hypophosphite slurry;

[0184] wherein the molar amount of the metal hydroxide is 30-50mol% and the molar amount of the sulfuric acid is 5-50mol%, based on 100% of the molar amount of the diethyl hypophosphite;

[0185] (B3) the diethyl hypophosphite slurry and a flocculant solution are mixed at 40-60℃, and stirring is performed to obtain a diethyl hypophosphite flocculate; the diethyl hypophosphite flocculate is filtered, washed ≥4 times, and dried to obtain the organic phosphonate flame retardant;

[0186] wherein the mass of the flocculant is 0.01-0.5%, based on 100% of the theoretically obtained mass of the diethyl hypophosphite salt.

[0187] It should be noted that the preparation method of the organic phosphonate flame retardant described in the present application is not limited to the aforementioned method I and method II, and other methods or routes can also be selected by those skilled in the art to obtain the low-acid-value organic phosphonate flame retardant proposed in the present application.

[0188] In the following specific embodiments, the test method of the organic phosphonate flame retardant is as follows:

[0189] (1) Content test of diethyl phosphinate, ethyl butyl phosphinate, ethyl phosphinate, and monoethyl phosphinate

[0190] The liquid chromatograph (LC20A, Shimadzu, Japan) was used for analysis and test, wherein diethyl phosphinate was analyzed by using a commercially available standard sample, ethyl butyl phosphinate was analyzed by using a pure product (prepared according to CN103172668A, Example 4) as a standard sample, ethyl phosphinate was analyzed by using a pure product (prepared according to CN104371142A, Example 2) as a standard sample, and monoethyl phosphinate was analyzed by using a pure product (prepared according to CN103172668A, Example 1) as a standard sample; the sample to be tested was dissolved in 5 times the mass of sulfuric acid aqueous solution (mass concentration 30%), and then diluted 20 times with a mobile phase for analysis and test; the mobile phase was a mixture of water and methanol with a mass ratio of 9:1, and 0.5% trifluoroacetic acid was added; the chromatographic column was ShimNex CS C18 5μm, 4.6*250mm, and the flow rate was 0.6mL / min; the mass content of each component was calculated by area normalization method.

[0191] (2) Content of alkali insoluble matter

[0192] 5g of the sample to be tested was stirred with 500g of sodium hydroxide aqueous solution (mass concentration 3%) at 35℃ for 30min, filtered with a filter paper with a precision of ≤2μm, and washed with 100g of water for 3 times, and then the filter paper was dried and weighed; the mass increase of the filter paper after drying was the mass of the insoluble matter, and the ratio of the mass of the insoluble matter to the mass of the sample to be tested (5g) was the mass content of the alkali insoluble matter.

[0193] (3) Content of other phosphorus-containing compounds

[0194] The sample to be tested was mixed with deuterated sodium hydroxide deuterated aqueous solution (mass concentration 10%) at a mass ratio of 1:30 to completely dissolve the sample, and then filtered; the obtained clear liquid was measured by nuclear magnetic resonance instrument (NMR, Bruker nuclear magnetic resonance NMR spectrometer, AVANCENEO 400MHz) to obtain nuclear magnetic phosphorus spectrum; the integral area ratio of the peaks other than the known diethyl phosphinate, ethyl butyl phosphinate, ethyl phosphinate, and monoethyl phosphinate was regarded as the content of the other phosphorus-containing compounds.

[0195] (4) Water-soluble acid value

[0196] Take 1 g of the sample to be tested, add 5.00 ± 0.01 g (m 乙醇 ) of ethanol to uniformly wet, then add 50 ± 0.01 g (m 水 ) of normal temperature water, weigh the total weight m0 with the bottle and stirring, after boiling in a closed state at 90℃ for 1 h, cool to 25℃ and keep constant temperature for 30 min, add ethanol aqueous solution (the mass ratio of ethanol to water is 1:10) to the total weight m0. Filter to obtain the mass of clear filtrate m1, measure the test acid value of the clear filtrate by the potentiometric titration test method, and measure the blank acid value of (m 水 +m 乙醇 ) by the potentiometric titration test method, wherein the concentration of potassium hydroxide solution used for titration is 0.05 mol / L, and the water-soluble acid value = test acid value × (m 水 +m 乙醇 ) / m1-blank acid value.

[0197] (5) Organic acid value

[0198] Take 1 g of the sample to be tested, add 50.0 ± 0.01 g (m 二氯甲烷 ) of dichloromethane to uniformly wet, then weigh the total weight m0 with the bottle and stirring, after boiling in a closed state at 90℃ for 1 h, cool to 25℃ and keep constant temperature for 30 min, add dichloromethane to the total weight m0; filter to obtain the mass of clear filtrate m1, measure the test acid value of the clear filtrate by the potentiometric titration test method, and measure the blank acid value of the weight m 二氯甲烷 by the potentiometric titration method, wherein the concentration of potassium hydroxide solution used for titration is 0.05 mol / L, and the organic acid value = test acid value × m 二氯甲烷 / m1-blank acid value.

[0199] (6) Mass content of sulfate radical

[0200] Refer to the method in the standard EN 14582:2007-“Determination of halogen content”, and measure by ion chromatography technology with external standard method.

[0201] In the following specific embodiments of the present application, all materials without preparation method provided are commercially available chemicals, and specific information of some materials is as follows:

[0202]

[0203]

[0204] The preparation method of the organic phosphonate flame retardant described in the present application will be described in detail below by taking a plurality of preparation examples as examples, but the preparation method of the organic phosphonate flame retardant is not limited to these preparation examples.

[0205] Preparation Example 1-5, Comparative Preparation Example 1-6

[0206] A method for preparing an organic phosphonate flame retardant, comprising the following steps:

[0207] (1) Put 31.8 kg of solid sodium hypophosphite monohydrate, 40 kg of water, 200 g of sodium persulfate, an antioxidant 1010 with a mass of m1, and an antioxidant 168 with a mass of m2 into an autoclave, replace with nitrogen for 3 times, pass ethylene through a pressure reducer to a constant pressure of 1.5 MPa, heat to 100°C, and keep the temperature for 4 h. During the 4 h of temperature keeping, continuously add 2500 g of a 15% mass content sodium persulfate aqueous solution, then keep the temperature at 100°C for 1 h, cool and vent, to obtain a sodium diethylphosphinate aqueous solution;

[0208] (2) Dilute the sodium diethylphosphinate aqueous solution obtained in step (1) to a mass content of 20% of sodium diethylphosphinate (containing 6 mol of sodium diethylphosphinate), heat to a temperature T1, continuously drop an aluminum sulfate aqueous solution (1 mol of aluminum sulfate with a mass content of 25%) within 1 h, and control the pH value with a potassium hydroxide solution (with a mass content of 5%) to obtain an aluminum diethylphosphinate slurry;

[0209] (3) At 50°C, add a flocculant aqueous solution prepared from an anionic polyacrylamide with a mass of m3 and 50 g of water to the aluminum diethylphosphinate slurry obtained in step (2), stir to a flocculation state, filter, wash the filter cake with 3 times the mass of water n times, and dry at 120°C to a constant weight to obtain an organic phosphonate flame retardant.

[0210] The specific process parameters of the preparation method and the related data of the organic phosphonate flame retardant prepared are shown in Table 1.

[0211] Table 1

[0212]

[0213]

[0214] Preparation Examples 6-8, Comparative Preparation Examples 7-10

[0215] A method for preparing an organic phosphonate flame retardant, the method being as follows:

[0216] (1) Put 39.6 kg of a 50% mass content hypophosphorous acid aqueous solution, 500 g of sodium persulfate, and an antioxidant with a mass of m4 into an autoclave, replace with nitrogen for 3 times, pass ethylene through a pressure reducer to a constant pressure of 1.5 MPa, heat to a temperature of 85°C, and keep the temperature for 5.5 h. During the temperature keeping process, continuously add 3500 g of a 10% mass content sodium persulfate aqueous solution, and then keep the temperature at 85°C for another 1.5 h. After cooling and emptying, an aqueous diethyl hypophosphite solution is obtained;

[0217] (2) Mix the aqueous diethyl hypophosphite solution obtained in step (1) (6 mol of diethyl hypophosphite), an aqueous sulfuric acid solution (30% mass content of sulfuric acid, 0.6 mol of sulfuric acid), and 2 mol of aluminum hydroxide, heat to 90°C, stir for 8 h, and adjust the pH value with a sodium hydroxide solution (10% mass content) to obtain a diethyl hypophosphite salt slurry;

[0218] (3) At 50°C, add a flocculating agent aqueous solution prepared from an anionic polyacrylamide with a mass of m5 and 50 g of water to the diethyl hypophosphite salt slurry obtained in step (2), stir until aluminum diethylphosphite flocculates are formed, filter, wash the filter cake with 3 times the mass of water for 5 times, and dry at 110°C to a constant weight to obtain an organic phosphonate flame retardant.

[0219] The specific process parameters of the preparation method and the related data of the prepared organic phosphonate flame retardant are shown in Table 2; “--” indicates that the material is not added.

[0220] Table 2

[0221]

[0222] The following examples will be described in detail with examples, but the polyamide composite is not limited to these examples.

[0223] In the following examples, the materials not provided in the preparation method are commercially available chemicals, and the specific information is as follows:

[0224]

[0225]

[0226] Examples 1-12, Comparative Examples 1-10

[0227] A polyamide composite, the types and amounts of the components are shown in Tables 3 and 4, and the amount of each component is “mass parts”.

[0228] The preparation method of the polyamide composite material comprises the following steps: mixing polyamide resin, glass fiber, organic phosphonate flame retardant, MPP, antioxidant and lubricant according to the formula amount to obtain a premix; adding the premix into a double-screw extruder, the rotation speed of the screw of the double-screw extruder is 380 rpm, the temperatures of the 1-12 zones of the PA66 system are 90℃, 180℃, 260℃, 250℃, 230℃, 230℃, 220℃, 220℃, 220℃, 220℃, 260℃ and 260℃ respectively, the temperatures of the 1-12 zones of the PA10T system are 120℃, 260℃, 310℃, 300℃, 260℃, 260℃, 260℃, 260℃, 260℃, 260℃, 290℃ and 310℃ respectively, and then the polyamide composite material is obtained through melt mixing and extrusion granulation.

[0229] The polyamide composite material is subjected to the following performance tests:

[0230] (1) Water boiling phosphorus content test: 50 g of polyamide composite material particles are added into 500 mL of 90℃ hot water, boiled for 1 h, cooled to room temperature, filtered, and the phosphorus content in the filtrate is measured by the ammonium molybdate spectrophotometric method in GB / T 11893-1989;

[0231] (2) Mold dirt test method: an injection molding machine is used, the polyamide composite material particles are continuously injected at 290℃, 285℃, 280℃ and 260℃ for 150 molds, the mold dirt sample collected in the last mold is taken out and weighed by an analytical balance;

[0232] The test data are shown in Tables 3 and 4.

[0233] Table 3

[0234]

[0235] Table 4

[0236]

[0237]

[0238] According to the data in Table 3, the polyamide composition provided by the application uses a low-acid-value organic phosphonate flame retardant, which can significantly reduce the mold dirt generated during injection molding, so that the mold dirt is ≤7.2 mg, the water boiling phosphorus content of the polyamide composition is ≤507 ppm, the water boiling precipitate content is reduced, the moisture and heat resistance of the polyamide composition is improved, and the service life of the polyamide composition under moisture and heat conditions is prolonged.

[0239] According to the test data in Table 4, the organic phosphonate flame retardant in Comparative Examples 1-10 has a high acid value, which results in more injection molding dirt of the polyamide composition, increased phosphorus content in boiling water, and poor stability under humid heat conditions.

[0240] The applicant states that the polyamide composite material and its application of the present application are illustrated by the above examples, but the present application is not limited to the above examples, that is, it does not mean that the present application must rely on the above examples to be implemented. Those skilled in the art should understand that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A polyamide composite, characterized in that, The polyamide composite comprises the following components by mass fraction: Polyamide resin 35-82 parts Reinforcing material 5-45 parts Organic phosphonate flame retardant 5-25 parts The water-soluble acid value of the organic phosphonate flame retardant is 0.1-0.3 mg KOH / g. The organic phosphonate flame retardant comprises the following components by mass fraction: Diethyl phosphinate salt 95-99.88 parts Ethyl butyl phosphinate salt 0.1-3 parts Ethyl phosphinate salt 0.01-1 parts Monoethyl phosphinate salt 0.01-1 parts.

2. The polyamide composite according to claim 1, characterized in that, The polyamide resin comprises any one of polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 46, polyamide 610, polyamide 611, polyamide 612, polyamide 1010, polyamide 6T, polyamide 9T, polyamide 10T or a combination of at least two thereof.

3. The polyamide composite of claim 1, wherein, The reinforcing material comprises any one of glass fiber, carbon fiber, polyaramid fiber, asbestos fiber, wollastonite fiber, ceramic fiber, potassium titanate whisker, basic magnesium sulfate whisker, silicon carbide whisker, aluminum borate whisker or a combination of at least two thereof.

4. The polyamide composite of claim 1, wherein, The cation of each of the diethylphosphinate salt, ethylbutylphosphinate salt, ethylphosphonate salt, monoethylphosphinate salt independently comprises any one of or a combination of at least two of Al 3+ , Ca 2+ , Cu 2+ , Zn 2+ , Fe 2+ , Fe 3+ , Ti 4+ .

5. The polyamide composite according to claim 4, characterized in that, The cation in the diethylphosphinate salt, ethylbutylphosphinate salt, ethylphosphonate salt, monoethylphosphinate salt is Al 3+ .

6. The polyamide composite of claim 1, wherein, The organic phosphonate flame retardant further comprises alkali insoluble substances, and the alkali insoluble substances comprise any one of hydroxide, oxide, phosphate, pyrophosphate, polyphosphate, phosphite or a combination of at least two thereof.

7. The polyamide composite according to claim 6, characterized in that The mass fraction of the alkali insoluble substances in the organic phosphonate flame retardant is ≤3 parts.

8. The polyamide composite of claim 1, wherein, The organic phosphonate flame retardant further comprises other phosphorus-containing compounds, and the mass fraction of the other phosphorus-containing compounds in the organic phosphonate flame retardant is ≤1 part.

9. The polyamide composite of claim 1, wherein, The organic acid value of the organic phosphonate flame retardant is ≤0.05 mg KOH / g.

10. The polyamide composite according to claim 9, characterized in that, The organic acid value of the organic phosphonate flame retardant is 0.001-0.04 mg KOH / g.

11. The polyamide composite of claim 1, wherein, The mass content of sulfate in the organic phosphonate flame retardant is 100-500 ppm.

12. The polyamide composite according to claim 11, characterized in that, The mass content of sulfate in the organic phosphonate flame retardant is 110-430 ppm.

13. The polyamide composite of claim 1, wherein, The polyamide composite further comprises melamine and / or piperazine pyrophosphate flame retardant 1-15 parts by mass fraction.

14. The polyamide composite according to claim 13, characterized in that, The melamine flame retardant comprises any one of melamine polyphosphate salt, melamine pyrophosphate salt, melam polyphosphate salt, melam pyrophosphate salt, melam phosphate salt, melam diethyl phosphinate salt, melam ethyl phosphinate salt, melam phosphite salt, melam alkyl phosphinate salt or a combination of at least two thereof.

15. The polyamide composite of claim 13, wherein, The mass ratio of the organic phosphonate flame retardant to the melamine and / or piperazine pyrophosphate flame retardant is 1:(0.1-3).

16. The polyamide composite of claim 1, wherein, The polyamide composite further comprises any one of synergistic flame retardant, antioxidant, lubricant or a combination of at least two thereof.

17. The polyamide composite of claim 16, wherein, The synergistic flame retardant comprises any one of zinc borate, zinc stannate, zinc sulfide, boehmite or a combination of at least two thereof.

18. The polyamide composite of claim 16, wherein, The mass fraction of the synergistic flame retardant in the polyamide composite is ≤5 parts.

19. The polyamide composite of claim 16, wherein, The polyamide composite further comprises 0.01-1 parts of antioxidant by mass fraction.

20. The polyamide composite of claim 16, wherein, The polyamide composite further comprises 0.01-1 parts of lubricant by mass fraction.

21. The polyamide composite of claim 1, wherein, The polyamide composite has a water boil phosphorus content of 510 ppm or less.

22. The polyamide composite of claim 21, wherein, The polyamide composite has a water boil phosphorus content of 370-507 ppm.

23. The polyamide composite of claim 1, wherein, The polyamide composite has an injection molding fouling of 7.5 mg or less.

24. The polyamide composite of claim 23, wherein, The polyamide composite has an injection molding fouling of 4-7.2 mg.

25. A process for the production of a polyamide composite according to any one of claims 1 to 24, characterized in that The preparation method comprises: melt blending a polyamide resin, a reinforcing material and an organic phosphonate flame retardant, and then extruding to obtain the polyamide composite.

26. The method of claim 25, wherein, The preparation method comprises the following steps: mixing a polyamide resin and an organic phosphonate flame retardant to obtain a premix; melt blending the premix and a reinforcing material, and then extruding to obtain the polyamide composite.

27. The method of claim 26, wherein, The mixed material further comprises any one or a combination of at least two of melamine flame retardant, synergistic flame retardant, antioxidant, lubricant.

28. The preparation method according to claim 25, characterized in that, The melt blending is performed in a screw extruder.

29. The method of claim 28, wherein, The temperature of the screw extruder is 180-330℃.

30. The method of claim 25, wherein, The extruding further comprises the steps of granulating and drying.

31. Use of the polyamide composite according to any one of claims 1-24 in electronic and electrical appliances, electrical product parts, energy storage devices, connectors or automotive parts.

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