CN110684344B - Halogen-free flame-retardant nylon composite material and preparation method and application thereof - Google Patents

Abstract

The invention relates to the technical field of preparation of flame-retardant nylon, in particular to a halogen-free flame-retardant nylon composite material and a preparation method and application thereof. The composite material comprises the following raw materials in parts by weight: 15-84.8 parts of nylon, 10-70 parts of modified flame retardant, 5-10 parts of toughening agent, 0.1-3 parts of lubricant and 0.1-2 parts of antioxidant; the modified flame retardant is subjected to plasma gas discharge treatment, namely: and (2) placing the flame retardant into a plasma reaction device, introducing one or a mixture of several plasma gases, and performing surface functionalization treatment on the flame retardant by using plasmas. The invention utilizes the low-temperature plasma technology to carry out surface treatment on the halogen-free flame retardant, improves the compatibility of the flame retardant and a nylon matrix, and is beneficial to improving the dispersibility of the flame retardant in nylon, thereby not only improving the flame retardant property of the nylon material, but also reducing the deterioration of the mechanical property of the material caused by the addition of the flame retardant.

Description

A halogen-free flame retardant nylon composite material and its preparation method and application

technical field

The invention relates to the technical field of flame retardant nylon preparation, in particular to a halogen-free flame retardant nylon composite material and a preparation method and application thereof.

Background technique

The information disclosed in this Background of the Invention is only for enhancement of understanding of the general background of the invention and should not necessarily be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art.

Nylon is one of the most widely used and most types of engineering plastics. Forming complex structural components is widely used in automobiles, electronic appliances, machinery, rail transit, sports equipment and other fields. However, nylon is a flammable plastic. In many fields, such as electronics, electrical appliances, rail transit, etc., high requirements are placed on the flame retardant properties of materials, which limits the application scope of nylon materials.

The flame retardant grade of nylon materials can be significantly improved by adding flame retardants, and many halogen-containing flame retardants (such as brominated compounds) can significantly improve the flame retardant properties of nylon materials. With people's attention to safety and environmental issues, traditional halogen flame retardants are gradually replaced by halogen-free flame retardants, such as hydroxide, nitrogen-based, and phosphorus-based flame retardants.

Although halogen-free flame retardants have the advantages of being environmentally friendly, the addition amount is significantly higher than that of brominated flame retardants. To achieve the flame retardant grade of UL94 standard V0, the addition amount of hydroxide often exceeds 50 parts. Other types The addition amount of halogen-free flame retardant should also be greater than 20 parts. How to disperse this high amount of flame retardant well into the nylon matrix is a big challenge.

Patent document CN104017356A discloses a preparation method of flame retardant nylon material, weigh 58.79-72.56 parts of nylon, 12.61-18.92 parts of melamine, 11.53-17.29 parts of phosphoric acid, and 3-5 parts of char-forming agent, and extrude and granulate after mixing evenly. , the flame retardant grade of the prepared nylon material is V0.

Patent document CN105392841A discloses a preparation method of flame-retardant high-temperature nylon. Weigh 20-80 parts of nylon, 10-40 parts of polyphosphate, 10-40 parts of polyphenylene ether, and 0-3 parts of polytetrafluoroethylene, and mix them evenly. After extrusion and granulation, the flame retardant grade of the prepared nylon material is V0.

Patent document CN107129679A discloses a toughened modified flame-retardant nylon bellows and a preparation method thereof. After mixing 100 parts of nylon, 5-10 parts of toughening agent, 10-20 parts of flame retardant, and 5-15 parts of auxiliary Extruded by special equipment at high temperature, the flame retardant grade of bellows is V2.

Patent document CN107057346A discloses a preparation method of a flame retardant nylon composition, weighing 60-93 parts of nylon 66 resin, 1-15 parts of silicone flame retardant, and 5-25 parts of nitrogen-based or phosphorus-based flame retardant, After mixing evenly, extruding and granulating, the limiting oxygen index of nylon material prepared by using the composite flame retardant is greater than 31.

Luo Hongxin et al. (Journal article: "Influence of Surface Modification on Flame Retardant Properties of Nylon 6/Magnesium Hydroxide", Insulation Materials, 2005, 38(6):34-38) Mg(OH) ₂ treated with coupling agent was used as The flame retardant nylon 6 composite material was prepared by the flame retardant, and it was found that when the amount of Mg(OH) ₂ was 40%, the oxygen index of the material could reach more than 30%, and the vertical combustion grade was V0.

Lv Xinran et al. (Journal article: "Preparation and Properties of Composite Modified Nanometer Magnesium Hydroxide Flame Retardant Nylon 6", Insulation Materials, 2013, 46(6): 36-40) Mg treated with stearic acid/calcium stearate (OH) ₂ was used as a flame retardant to prepare a flame retardant nylon 6 composite material. It was found that when the amount of Mg(OH) ₂ was 45%, the oxygen index of the material could reach more than 27%.

However, the inventors have found from the literature represented by the above-mentioned flame retardant nylon composite materials: before mixing and granulating nylon, flame retardant and other additives, the flame retardant in the formula is not surface-treated, because the flame retardant Most of the flame retardants are inorganic or small molecular compounds, which have poor compatibility with the nylon matrix. When some researchers treat the surface of flame retardants, they use wet chemical methods, which require multi-step chemical reactions, which are complicated to operate and are not conducive to large-scale production.

SUMMARY OF THE INVENTION

In view of the above existing problems, the present invention provides a halogen-free flame retardant nylon composite material and a preparation method and application thereof; the present invention utilizes low temperature plasma to modify the flame retardant (surface functionalization), effectively improving the flame retardant The dispersibility in nylon improves the performance of halogen-free flame retardant nylon.

For realizing the above-mentioned purpose of the invention, the technical means adopted in the present invention are:

First, the present invention discloses a halogen-free flame retardant nylon composite material. In parts by weight, its raw material composition includes: 15-84.8 parts of nylon, 10-70 parts of modified flame retardant, 5-10 parts of toughening agent, lubricant The modified flame retardant is a flame retardant treated by plasma discharge, specifically: placing the flame retardant in a plasma reaction device, and passing a A mixture of one or several gases, and the surface of the flame retardant is functionalized by plasma to generate polar groups such as hydroxyl, carboxyl, and amine groups on its surface.

Secondly, the present invention discloses a preparation method of the above halogen-free flame retardant nylon composite material, which comprises the following steps: mixing nylon, modified flame retardant, toughening agent, lubricant and antioxidant, and then extruding, and extruding the extruded product through Traction, cooling, drying, dicing, and that's it.

The characteristics of the halogen-free flame-retardant nylon composite material of the invention are: using low-temperature plasma technology to modify the surface of different types of halogen-free flame retardants, and generating hydroxyl, carboxyl, amine groups and other groups on the surface of the flame retardant, these radicals During the extrusion process, the group undergoes condensation reaction with the carboxyl and amine groups at the end of the nylon, and nylon segment grafts are formed on the surface of the flame retardant. These grafts have good compatibility with the nylon matrix and can significantly improve the resistance. The dispersibility of the flame retardant in the nylon matrix.

In addition, compared with the method adopted in the patent document CN201711263708.6, the present invention is to make groups such as hydroxyl groups, carboxyl groups, and amine groups generated on the surface of the flame retardant to undergo condensation reactions with the carboxyl groups and amine groups at the nylon end during the extrusion process. , a nylon segment graft with good compatibility with nylon is formed on the surface of the flame retardant. In the above-mentioned patent documents, in order to disperse the carbon microspheres into the polyester matrix, firstly, hydroxyl and carboxyl groups are generated on the surface of the carbon microspheres by plasma technology. The hydroxyl and carboxyl groups of dihydroguanidine have no active groups such as amino and carboxyl groups of nylon segments in the polyester polymer. In order to better disperse the carbon microspheres into the polyester, the inventors conducted a In situ polymerization of polyester monomers. It can be seen that the patent document CN201711263708.6 adopts three kinds of plasma treatment, microsphere surface grafting flame retardant and microsphere surface in-situ polyester monomer polymerization in order to realize the purpose of dispersing carbon microspheres and polyester flame retardant. The processing process is not only different from the technical idea of the present invention, but also the operation process is cumbersome, which is not conducive to industrialized production. The invention utilizes the active groups such as amino group and carboxyl group of nylon segment, and directly obtains the flame retardant with groups such as hydroxyl group, carboxyl group and amino group on the surface by plasma treatment of the flame retardant, and can directly realize the flame retardant in the extruder. good dispersion, and this method has the advantages of simple operation process, which is conducive to the realization of industrialization.

Compared with the prior art, the present invention has achieved the following beneficial effects:

(1) The present invention uses low-temperature plasma technology to perform surface treatment on the halogen-free flame retardant, which improves the compatibility of the flame retardant with the nylon matrix, which is beneficial to improve the dispersibility of the flame retardant in nylon, which can not only improve the The flame retardant properties of nylon materials are also beneficial to reduce the deterioration of the mechanical properties of the materials due to the addition of flame retardants.

(2) The low-temperature plasma treatment method adopted in the present invention has the advantages of simple operation, no chemical solvent, environment-friendly, and favorable for large-scale production.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

As mentioned above, since most of the flame retardants are inorganic or small molecular compounds, they have poor compatibility with the nylon matrix, and it is difficult to effectively disperse the high content of flame retardants into the nylon matrix, resulting in a significant decrease in the mechanical properties of composite materials. Therefore, the present invention proposes a halogen-free flame retardant nylon composite material and a preparation method thereof.

In some typical embodiments, the plasma reaction device is a low temperature plasma reaction device, and the discharge mode can be any one of glow discharge, corona discharge, dielectric barrier discharge, radio frequency discharge and microwave discharge.

In some typical embodiments, the plasma reaction gas is one or a mixture of air, oxygen, nitrogen, carbon dioxide, argon, helium, and ammonia. Preferably, the plasma reaction gas is carbon dioxide or ammonia, and the flame retardants treated with these two gases can more significantly improve the flame retardant properties and mechanical properties of the halogen-free flame retardant nylon composite material.

In some typical embodiments, the conditions for the plasma treatment of the flame retardant powder are: gas pressure 5-500Pa, discharge power 10-800W, and discharge time 5-60min.

In some typical embodiments, the nylon is any one of nylon 6, nylon 66, nylon 46, nylon 610, nylon 612, nylon 9, nylon 11, nylon 12, nylon 1010, nylon 1012, nylon 1212, etc. or several mixtures.

In some typical embodiments, the toughening agent is a maleic anhydride polyolefin graft: maleic anhydride grafted polyolefin includes maleic anhydride grafted low density polyethylene (LDPE), maleic anhydride grafted high density polyethylene Polyethylene (HDPE), Maleic Anhydride Grafted Linear Low Density Polyethylene (LLDPE), Maleic Anhydride Grafted Polypropylene (PP), Maleic Anhydride Grafted Ethylene Propylene Copolymer (EPR), Maleic Anhydride Grafted Ethylene Any one or a mixture of octene copolymer (POE) and maleic anhydride grafted ethylene-propylene-diene rubber (EPDM).

In some typical embodiments, the flame retardant is magnesium hydroxide (Mg(OH) ₂ ), aluminum hydroxide (Al(OH) ₃ ), antimony trioxide (Sb ₂ O ₃ ), zinc borate (ZnB) ₄ O ₇ ), red phosphorus, coated red phosphorus, microencapsulated red phosphorus, melamine cyanurate (MCA), melamine polyphosphate (MPP), melamine phosphate (MP), ammonium polyphosphate (APP), Any one or more of pentaerythritol, aluminum dimethyl phosphinate, aluminum diethyl phosphinate, aluminum dipropyl phosphinate, aluminum dibutyl phosphinate, aluminum diphenyl phosphinate mixture.

In some typical embodiments, the lubricant is polyethylene wax, microcrystalline wax, liquid paraffin, solid paraffin, chlorinated paraffin, oxidized polyethylene wax, silicone oil, stearic acid, butyl stearate, stearic acid Any one or a mixture of calcium, zinc stearate, oleic acid amide, ethylene bis-stearamide, erucic acid amide and glycerol trihydroxystearate.

In some typical embodiments, the antioxidant is [tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate] pentaerythritol ester (preferably antioxidant 1010), 3-(3,5 -Di-tert-butyl-4-hydroxy)propenyl octadecyl (preferably antioxidant 1076), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propane Acyl) hexamethylenediamine (preferably antioxidant 1098), 2,6-di-tert-butyl-4-cresol (preferably antioxidant 264), 2,4,6-tri-tert-butylphenol (preferably Antioxidant 246), (2,4-di-tert-butylphenyl) phosphite triester (preferably antioxidant 168) in any one or a mixture of several.

In some typical embodiments, the mixing time of the nylon, the modified flame retardant, the toughening agent, the lubricant, and the antioxidant is not less than 30 minutes.

In some typical embodiments, the extrusion process parameters are: between 200°C and 330°C, the main screw speed is 5-300 rpm, and the feeding screw speed is 1-50 rpm.

In some typical embodiments, the above-mentioned halogen-free flame retardant nylon composite material and its preparation method are also used in the fields of electronics, electrical appliances, rail transportation and the like.

The present invention will now be further described with reference to specific embodiments.

In the following examples, the nylon is nylon 6 from China Shenma Group Co., Ltd., purchased from Guangdong Xinhui Meida Nylon Co., Ltd., M52800 (this is the product model). The maleic anhydride grafted POE was purchased from Shandong Kehua Saibang New Materials Co., Ltd., KE1. The flame retardant magnesium hydroxide was purchased from Shanghai Baodi Chemical; the flame retardant aluminum diethylphosphinate was purchased from Qingdao Opry New Materials Co., Ltd., and the flame retardant melamine cyanurate was purchased from Sichuan Fine Chemical Industry Research Institute . The lubricant is calcium stearate, purchased from Kaixiang Chemical. The antioxidant was Antioxidant 1098 (BASF). The model of the low-temperature plasma reaction device is OTF-1200X, which was purchased from Hefei Kejing Material Technology Co., Ltd.

Example 1

A preparation method of halogen-free flame-retardant nylon composite material, comprising the following steps:

Take 42 parts of nylon, 7 parts of maleic anhydride grafted POE, 50 parts of magnesium hydroxide, 0.5 part of calcium stearate, 10980.5 parts of antioxidant, mix the above-mentioned various raw materials in a high-speed mixer for 30min, and then put them into extrusion In the hopper of the machine, at 210-260 ° C, the main screw speed is 80 rpm, and the feeding screw speed is 20 rpm. The cooling water temperature is 30° C.), drying (air drying is performed naturally), and pelletizing (the rotation speed of the pelletizer is 30 Hz) to obtain a halogen-free flame retardant nylon composite material.

Example 2

A preparation method of halogen-free flame-retardant nylon composite material, comprising the following steps:

(1) put 55 parts of magnesium hydroxide into the low temperature plasma reaction device, feed argon gas as plasma reaction gas, gas pressure 200Pa, radio frequency discharge power 700W, discharge time 50min, obtain modified magnesium hydroxide, standby.

(2) Take 42 parts of nylon, 7 parts of maleic anhydride grafted POE, 50 parts of modified magnesium hydroxide, 0.5 part of calcium stearate, and 0.5 part of antioxidant 1098 prepared in step (1) of this example; The raw materials were mixed in a high-speed mixer for 30min, then put into the extruder hopper, and extruded under the conditions of 210-260°C, the main screw speed was 80 rpm, and the feeding screw speed was 20 rpm. The output is drawn (traction rate 10 m/min), cooled (cooling water temperature 30°C), dried (air-drying naturally), and pelletized (pelletizer speed 30Hz) to obtain halogen-free flame retardant nylon composite material.

Example 3

A preparation method of halogen-free flame-retardant nylon composite material, comprising the following steps:

(1) put 15 parts of magnesium hydroxide into the low temperature plasma reaction device, feed argon gas as plasma reaction gas, gas pressure 5Pa, radio frequency discharge power 800W, discharge time 60min, obtain modified magnesium hydroxide, standby.

(2) Take 15 parts of nylon, 5 parts of maleic anhydride grafted POE, 10 parts of modified magnesium hydroxide prepared in step (1) of this example, 0.1 part of polyethylene wax, and 0.1 part of antioxidant 1098; The raw materials were mixed in a high-speed mixer for 30min, then put into the extruder hopper, and extruded under the conditions of 210-260°C, the main screw speed was 80 rpm, and the feeding screw speed was 20 rpm. The output is drawn (traction rate 10 m/min), cooled (cooling water temperature 30°C), dried (air-drying naturally), and pelletized (pelletizer speed 30Hz) to obtain halogen-free flame retardant nylon composite material.

Example 4

A preparation method of halogen-free flame-retardant nylon composite material, comprising the following steps:

(1) put 80 parts of magnesium hydroxide into the low temperature plasma reaction device, feed argon gas as plasma reaction gas, gas pressure 500Pa, radio frequency discharge power 100W, discharge time 5min, obtain modified magnesium hydroxide, standby.

(2) Take 84.8 parts of nylon, 10 parts of maleic anhydride grafted POE, 70 parts of modified magnesium hydroxide prepared in step (1) of this example, 3 parts of polyethylene wax, and 2 parts of antioxidant 1098; The raw materials were mixed in a high-speed mixer for 30min, then put into the extruder hopper, and extruded under the conditions of 210-260°C, the main screw speed was 80 rpm, and the feeding screw speed was 20 rpm. The output is drawn (traction rate 10 m/min), cooled (cooling water temperature 30°C), dried (air-drying naturally), and pelletized (pelletizer speed 30Hz) to obtain halogen-free flame retardant nylon composite material.

Example 5

A preparation method of a halogen-free flame retardant nylon composite material is the same as that of Example 2, except that the plasma reaction gas is nitrogen.

Example 6

A preparation method of a halogen-free flame retardant nylon composite material is the same as that of Example 2, except that the plasma reaction gas is air.

Example 7

A preparation method of a halogen-free flame-retardant nylon composite material is the same as that of Example 2, except that the plasma reaction gas is oxygen.

Example 8

A preparation method of a halogen-free flame retardant nylon composite material is the same as that of Example 2, except that the plasma reaction gas is carbon dioxide.

Example 9

A preparation method of a halogen-free flame retardant nylon composite material is the same as that of Example 2, except that the plasma reaction gas is ammonia gas.

Example 10

A preparation method of halogen-free flame-retardant nylon composite material, comprising the following steps:

Take 62 parts of nylon, 7 parts of maleic anhydride grafted POE, flame retardant (20 parts of aluminum diethylphosphinate + 10 parts of melamine cyanurate), 0.5 part of calcium stearate, 0.5 part of antioxidant 1098, The above-mentioned various raw materials were mixed in a high-speed mixer for 30min, and then put into the extruder hopper, at 210℃-260℃, the main screw speed was 80 rpm, and the feeding screw speed was 20 rpm. Extrusion, the extrudate is pulled (the pulling speed is 10 m/min), cooled (cooling water temperature is 30 ° C), dried (air is naturally dried), and pelletized (the speed of pelletizer is 30 Hz) to obtain halogen-free flame retardant nylon composite Material.

Example 11

A preparation method of halogen-free flame-retardant nylon composite material, comprising the following steps:

(1) Take 20 parts of aluminum diethyl phosphinate and 10 parts of melamine cyanurate, put them into a low temperature plasma reaction device, feed argon gas, gas pressure 200Pa, radio frequency discharge power 700W, discharge time 50min, The modified flame retardant was obtained and used for later use.

(2) 62 parts of nylon, 7 parts of maleic anhydride grafted POE, the modified flame retardant prepared in step (1) of this example, 0.5 part of calcium stearate, and 0.5 part of antioxidant 1098 were placed in a high-speed mixer Mix for 30min, then put it into the extruder hopper, extrude under the condition of 210℃-260℃, the main screw speed is 80 rev/min, and the feeding screw speed is 20 rev/min. speed of 10 m/min), cooling (cooling water temperature 30° C.), drying (air drying), pelletizing (pelletizer rotation speed 30 Hz), to obtain halogen-free flame retardant nylon composite material.

Example 12

A preparation method of a halogen-free flame retardant nylon composite material is the same as that of Example 9, except that the plasma reaction gas is nitrogen.

Example 13

A preparation method of a halogen-free flame retardant nylon composite material is the same as that of Example 2, except that the plasma reaction gas is air.

Example 14

A preparation method of a halogen-free flame-retardant nylon composite material is the same as that of Example 2, except that the plasma reaction gas is oxygen.

Example 15

A preparation method of a halogen-free flame retardant nylon composite material is the same as that of Example 2, except that the plasma reaction gas is carbon dioxide.

Example 16

A preparation method of a halogen-free flame retardant nylon composite material is the same as that of Example 2, except that the plasma reaction gas is ammonia gas.

Performance Testing:

The properties of the flame-retardant nylon composite materials of Examples 1-9 are shown in Table 1. Among them, Example 1 is a control group, and the flame retardant magnesium hydroxide used in it does not use low-temperature plasma for surface functionalization.

Table 1

The properties of the flame-retardant nylon composite materials of Examples 10-16 are shown in Table 2, wherein, Example 10 is a control group, and the flame retardant used in it does not use low-temperature plasma for surface functionalization. In addition, the same as Examples 1-9 In contrast, examples 10-16 use nitrogen-phosphorus compound flame retardants.

Table 2

It can be seen from Table 1 and Table 2 that the flame retardant grade of the flame retardant nylon composite prepared by adding the flame retardant without low temperature plasma treatment can reach V0, but the tensile strength and impact strength of the composite material are not ideal. After the flame retardant was treated with low-temperature plasma of different gases, the flame retardant grade of the composite material reached V0, and the tensile and impact properties of the material were significantly improved, which indicated that the surface modification of the flame retardant was carried out. , which significantly improves the dispersion of the flame retardant in the nylon matrix. After further research in the present invention, it is found that this is due to the modification that makes a large number of hydroxyl, carboxyl, amine and other groups on the surface of the flame retardant. These groups are in During the extrusion process, a condensation reaction occurs with the carboxyl and amine groups at the end of nylon, and nylon segment grafts are formed on the surface of the flame retardant. These grafts have good compatibility with the nylon matrix, thereby improving the flame retardant. The dispersibility in the nylon matrix, and the significant improvement of the dispersibility is beneficial to reduce the deterioration of the mechanical properties of the material due to the addition of flame retardants, so that the prepared flame retardant nylon composite has both excellent flame retardant properties and mechanical properties.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (13)

1. The halogen-free flame-retardant nylon composite material is characterized by comprising the following raw materials in parts by weight: 15-84.8 parts of nylon, 10-70 parts of modified flame retardant, 5-10 parts of toughening agent, 0.1-3 parts of lubricant and 0.1-2 parts of antioxidant; the modified flame retardant is subjected to plasma gas discharge treatment;

the treatment method of the modified flame retardant comprises the following steps: putting the flame retardant into a plasma reaction device, introducing one or a mixture of several plasma gases, and performing surface functionalization treatment on the flame retardant by using plasmas to obtain the flame retardant;

wherein the plasma reaction gas is one or a mixture of air, oxygen, nitrogen, carbon dioxide, argon and helium; the flame retardant is any one or a mixture of more of magnesium hydroxide, aluminum hydroxide, antimony trioxide, zinc borate, red phosphorus, coated red phosphorus, melamine cyanurate, melamine polyphosphate, melamine phosphate, ammonium polyphosphate, pentaerythritol, aluminum dimethyl phosphinate, aluminum diethyl phosphinate, aluminum dipropyl phosphinate, aluminum dibutyl phosphinate and aluminum diphenyl phosphinate.

2. The halogen-free, flame retardant nylon composite of claim 1 wherein the plasma reaction gas is carbon dioxide.

3. The halogen-free flame retardant nylon composite material of claim 1 wherein the plasma treatment conditions of the flame retardant powder are: gas pressure of 5-500Pa, discharge power of 10-800W, and discharge time of 5-60 min.

4. The halogen-free flame-retardant nylon composite material according to claim 1, wherein the plasma reaction device is a low-temperature plasma reaction device, and the discharge mode comprises any one of glow discharge, corona discharge, dielectric barrier discharge, radio frequency discharge and microwave discharge.

5. The halogen-free flame retardant nylon composite material of claim 1 wherein the nylon is any one or a mixture of nylon 6, nylon 66, nylon 46, nylon 610, nylon 612, nylon 9, nylon 11, nylon 12, nylon 1010, nylon 1012, and nylon 1212.

6. The halogen-free flame retardant nylon composite of claim 1 wherein the toughening agent is a maleic anhydride polyolefin graft: the maleic anhydride grafted polyolefin comprises any one or a mixture of more of maleic anhydride grafted low-density polyethylene, maleic anhydride grafted high-density polyethylene, maleic anhydride grafted linear low-density polyethylene, maleic anhydride grafted polypropylene, maleic anhydride grafted ethylene propylene copolymer, maleic anhydride grafted ethylene octene copolymer and maleic anhydride grafted ethylene propylene diene monomer.

7. The halogen-free flame retardant nylon composite material of claim 1 wherein the coated red phosphorus is microencapsulated red phosphorus.

8. The halogen-free flame retardant nylon composite material of claim 1, wherein the lubricant is any one or a mixture of polyethylene wax, microcrystalline wax, liquid paraffin, solid paraffin, chlorinated paraffin, oxidized polyethylene wax, silicone oil, stearic acid, butyl stearate, calcium stearate, zinc stearate, oleamide, ethylene bis stearamide, erucamide and glycerol tristearate.

9. The halogen-free flame retardant nylon composite material of claim 1 wherein the antioxidant is any one or a mixture of several of pentaerythritol tetrakis (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, octadecyl 3- (3, 5-di-tert-butyl-4-hydroxy) propene, hexamethylenediamine, 2, 6-di-tert-butyl-4-cresol, 2,4, 6-tri-tert-butylphenol, and triester 2, 4-di-tert-butylphenyl phosphite.

10. The preparation method of the halogen-free flame retardant nylon composite material according to any one of claims 1 to 9, characterized by comprising the steps of: mixing nylon, modified flame retardant, toughening agent, lubricant and antioxidant, extruding, and drawing, cooling, drying and granulating the extrudate to obtain the flame-retardant modified flame-retardant nylon.

11. The method of claim 10, wherein the mixing time is not less than 30 min.

12. The method of claim 10, wherein the extrusion process parameters are: the rotating speed of the main screw is 5-300 r/min and the rotating speed of the feeding screw is 1-50 r/min at the temperature of 200-330 ℃.

13. Use of the halogen free flame retardant nylon composite material according to any of claims 1 to 9 and/or the halogen free flame retardant nylon composite material prepared by the method according to any of claims 10 to 12 in the fields of electronics, electrical appliances, rail transportation.