Environment-friendly green halogen-free flame-retardant cable and preparation method thereof

Abstract

The application discloses an environment-friendly green halogen-free flame-retardant cable and a preparation method thereof, and comprises the following steps: twisting copper wires to form a wire core, coating modified resin on the surface of the wire core to form an insulation layer, coating copper wire metal shielding tape to form a shielding layer, and coating modified resin to form a protective layer, so that the environment-friendly green halogen-free flame-retardant cable is prepared. Under the initiation of peroxide, stable C-S chemical bonds are formed between the modified additive and the ethylene-vinyl acetate main chain through free radical coupling, so that the migration, precipitation and volatilization of the flame-retardant component under the action of long-term use, high temperature, oil stains or an electric field are prevented, the flame-retardant performance is lifelong effective, the service life of the cable is significantly prolonged, and when the cable is burned, the modified additive can efficiently capture key active free radicals H and OH in a flame chain reaction, interrupts the combustion chain propagation, and the modified additive can promote the dehydration and carbonization of the polymer matrix to form a P-Si-O-C hybrid carbon layer, so that the flame-retardant and smoke-suppressing effect of the cable is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of cables, specifically to an environmentally friendly, green, halogen-free flame-retardant cable and its preparation method. Background Technology

[0002] With increasing societal demands for fire safety and environmental protection, traditional PVC cables, which release large amounts of toxic and corrosive gases such as hydrogen chloride during combustion, are gradually being phased out of the market. Halogen-free flame-retardant cables, characterized by halogen-free, low-smoke, and low-toxicity properties, have become the mainstream direction for industry development. However, current mainstream technologies still face multiple challenges. First, to achieve high flame-retardant ratings, it is typically necessary to fill the polyolefin substrate with large amounts of inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide, often reaching 120% to 150% of the matrix resin. This leads to severe degradation of material flexibility and processing performance, making it difficult to simultaneously meet the balance requirements of flame retardancy and mechanical properties. Second, while existing organophosphorus or nitrogen-based flame retardants can improve flame-retardant efficiency, they are mostly small-molecule additives. Under conditions of long-term electrical heating or contact with oil, these additives easily migrate and precipitate onto the material surface, causing flame-retardant performance to decay over time, failing to achieve effective protection throughout the entire life cycle. In addition, most of the reported phosphorus-silicon synergistic flame retardant systems adopt physical blending methods. During combustion, each component tends to form its own layer, making it difficult to form a continuous and dense hybrid char layer in situ. This results in low synergistic efficiency, and the char layer is prone to cracking and falling off in the fire, weakening the condensed phase barrier effect, generating a large amount of smoke, and causing serious pollution. Summary of the Invention

[0003] The purpose of this invention is to provide an environmentally friendly, green, halogen-free flame-retardant cable and its preparation method, which solves the problem that flame-retardant cables currently produce a large amount of smoke when burning.

[0004] The objective of this invention can be achieved through the following technical solutions: A method for preparing an environmentally friendly, green, halogen-free flame-retardant cable includes the following steps: Step A1: Mix pentaerythritol phosphate and acetonitrile, purge with nitrogen, stir and add pyridine at a speed of 150-200 r / min and a temperature of 20-25℃, heat to 55-60℃, add vinyltrichlorosilane, heat to 85-90℃, and react for 6-8 hours to obtain the flame retardant additive. Step A2: Mix the modified polysiloxane, flame retardant additive, caster catalyst and toluene, purge with nitrogen, and react for 6-8 hours at a speed of 200-300 r / min and a temperature of 80-85℃ to obtain the functionalized additive. Mix the functionalized additive, mercaptoacetic acid, 4-dimethylaminopyridine and dichloromethane, purge with nitrogen, and stir at a speed of 150-200 r / min and a temperature of 0-5℃, add N,N'-dicyclohexylcarbodiimide, raise the temperature to 25-30℃, and react for 20-24 hours to obtain the modified additive. Step A3: Mix ethylene-vinyl acetate masterbatch, modified additives, and dicumyl peroxide. Mix at 30 r / min and 120-130℃ for 8-10 minutes. Then, perform open mixing at 170-175℃ for the front roller and 160-165℃ for the rear roller to obtain modified resin. Twist copper wires to form a core. Sequentially coat the core surface with modified resin to form an insulation layer, copper wire metal shielding tape to form a shielding layer, and modified resin to form a protective layer to obtain an environmentally friendly, green, halogen-free flame-retardant cable.

[0005] Furthermore, the molar ratio of pentaerythritol phosphate, pyridine, and vinyltrichlorosilane in step A1 is 1:3:4.

[0006] Furthermore, the molar ratio of Si-H bonds on the modified polysiloxane and the flame retardant additive in step A2 is 1:1, the amount of cassette catalyst is 0.1% of the mass of the flame retardant additive, and the molar ratio of hydroxyl groups, mercaptoacetic acid, 4-dimethylaminopyridine and N,N'-dicyclohexylcarbodiimide on the functionalized additive is 1:1.5:0.2:1.5.

[0007] Furthermore, the weight ratio of ethylene-vinyl acetate masterbatch, modifying additive and dicumyl peroxide mentioned in step A3 is 100:10:1.2.

[0008] Furthermore, the modified polysiloxane is prepared by the following steps: Step B1: Mix DOPO and magnolol, purge with nitrogen, and react for 20-24 hours at a speed of 150-200 r / min and a temperature of 160-165℃ to obtain an intermediate. Mix the intermediate, epichlorohydrin, tetrabutylammonium bromide, and dioxane, purge with nitrogen, and react for 2-3 hours at a speed of 200-300 r / min and a temperature of 60-65℃. Add an aqueous solution of sodium hydroxide, raise the temperature to 75-80℃, and continue the reaction for 2-3 hours to obtain the modifier. Step B2: N-Allyl tert-butyl carbamate, dimethylhydrochlorosilane, caster catalyst and toluene are mixed and purged with nitrogen. Under nitrogen protection, the mixture is stirred and 2,6-di-tert-butylpyridine is added at a speed of 200-300 r / min and a temperature of 50-60℃. The reaction is carried out for 6-8 h to obtain the end-capping agent. Lithium trimethylsilanolate is dissolved in tetrahydrofuran and purged with nitrogen. Under nitrogen protection, the mixture is stirred and tetramethylcyclotetrasiloxane and octamethylcyclotetrasiloxane are added at a speed of 200-300 r / min and a temperature of 0℃. The mixture is heated to 25-30℃ and reacted for 6-8 h. Then the end-capping agent is added and the reaction is carried out for 1-1.5 h to obtain the pretreated polysiloxane. Step B3: Dissolve the pretreated polysiloxane in toluene, purge with nitrogen, stir and add trifluoroacetic acid at a speed of 200-300 r / min and a temperature of 20-25℃, and react for 1-2 h. Then cool to 0℃, add triethylamine to adjust the pH to 8, and obtain aminopolysiloxane. Mix aminopolysiloxane, modifier, triethylamine and xylene, purge with nitrogen, and react for 6-8 h at a speed of 80-85℃ to obtain modified polysiloxane.

[0009] Furthermore, in step B1, the molar ratio of DOPO and magnolol is 2:1, the ratio of the intermediate, epichlorohydrin, tetrabutylammonium bromide, and sodium hydroxide aqueous solution is 1 mol: 2.2 mol: 0.1 mol: 200 mL, and the mass fraction of the sodium hydroxide aqueous solution is 25%.

[0010] Furthermore, in step B2, the molar ratio of N-allyl tert-butyl carbamate, dimethylhydrochlorosilane, and 2,6-di-tert-butylpyridine is 1.2:1.3:0.15, the amount of cassette catalyst is 0.2% of the mass of dimethylhydrochlorosilane, and the molar ratio of lithium trimethylsilanolate, tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, and end-capping agent is 1.5:0.5:4:1.

[0011] Furthermore, in step B3, the molar ratio of the pretreated polysiloxane to trifluoroacetic acid is 1:5, the molar ratio of the aminopolysiloxane to the modifier is 1:2.2, and the amount of triethylamine used is 0.3% of the mass of the modifier.

[0012] The beneficial effects of this invention are as follows: This application discloses an environmentally friendly, green, halogen-free, flame-retardant cable, which is produced by stranding copper wires to form a core, sequentially coating the core surface with modified resin to form an insulation layer, copper wire metal shielding tape to form a shielding layer, and modified resin to form a protective layer. The modified additive is prepared by reacting pentaerythritol phosphate and vinyltrichlorosilane as raw materials, so that the hydroxyl groups on pentaerythritol phosphate react with the Si-Cl bonds on vinyltrichlorosilane to obtain a flame-retardant additive. The modified polysiloxane is reacted with the flame-retardant additive, so that the Si-H bonds on the modified polysiloxane react with the double bonds on the flame-retardant additive to obtain a functionalized additive. The functionalized additive is reacted with mercaptoacetic acid, so that the hydroxyl groups on the functionalized additive and the carboxyl groups on the mercaptoacetic acid are esterified to obtain a modified additive.

[0013] Modified polysiloxanes are prepared by reacting DOPO with magnolol, causing the pH bonds on DOPO to react with the double bonds on magnolol to obtain an intermediate. This intermediate is then reacted with epichlorohydrin, causing the phenolic hydroxyl groups on the intermediate to react with the epoxy groups on epichlorohydrin. The reaction is then cyclically closed in the presence of sodium hydroxide solution to form new epoxy groups, thus obtaining a modifier. Furthermore, N-allylcarbamate tert-butyl ester is reacted with dimethylchlorosilane, causing the double bonds on N-allylcarbamate to react with the Si-H bonds on dimethylchlorosilane to obtain a modified polysiloxane. A capping agent is used, with trimethylsilyllithium as an initiator and tetramethylcyclotetrasiloxane and octamethylcyclotetrasiloxane as polymerizing monomers, to form a polysiloxane with lithium silanolate at one end and Si-H bonds in the side chain. Then, a capping agent is added, causing the Si-Cl bonds on the capping agent to react with the lithium silanolate, to obtain a pretreated polysiloxane. The pretreated polysiloxane is treated with trifluoroacetic acid to deprotect the amino group, to obtain an amino polysiloxane. The amino polysiloxane is then reacted with a modifier, causing the amino group on the amino polysiloxane to react with the epoxy group on the modifier, to obtain a modified polysiloxane.

[0014] Under the initiation of peroxides, the modified additives form stable CS chemical bonds with the ethylene-vinyl acetate backbone through free radical coupling, eliminating the migration, precipitation, and volatilization of flame retardant components under long-term use, high temperature, oil contamination, or electric field effects. The flame retardant performance is effective for life, significantly extending the cable life. During combustion, the DOPO units in the modified additives decompose upon heating, releasing phosphorus-containing small molecule free radicals such as PO· and PO2·. These radicals can efficiently capture the key active free radicals H· and OH· in the flame chain reaction, interrupting the combustion chain propagation. Furthermore, the modified additives can promote the dehydration and carbonization of the polymer matrix, forming a P-Si-OC hybrid carbon layer. Its high-temperature strength and barrier properties far exceed those of a single carbon layer or silicon layer, greatly improving the flame retardant and smoke-suppressing effect of the cable. Detailed Implementation

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1: A method for preparing an environmentally friendly, green, halogen-free flame-retardant cable, specifically including the following steps: Step A1: Mix pentaerythritol phosphate and acetonitrile, purge with nitrogen, stir and add pyridine at 150 r / min and 20°C, heat to 55°C, add vinyltrichlorosilane, heat to 85°C, and react for 6 h to obtain flame retardant additive. Step A2: Mix modified polysiloxane, flame retardant additive, caster catalyst and toluene, purge with nitrogen, and react for 6 h at 200 r / min and 80 °C to obtain functionalized additive. Mix functionalized additive, mercaptoacetic acid, 4-dimethylaminopyridine and dichloromethane, purge with nitrogen, stir and add N,N'-dicyclohexylcarbodiimide at 150 r / min and 0 °C, heat to 25 °C and react for 20 h to obtain modified additive. Step A3: Mix ethylene-vinyl acetate masterbatch, modifying additives and dicumyl peroxide, and knead for 8 minutes at a speed of 30 r / min and a temperature of 120°C. Then, perform open mixing at a front roller temperature of 170°C and a rear roller temperature of 160°C to obtain modified resin. Twist copper wires to form a core, and then coat the core surface with modified resin to form an insulation layer, copper wire metal shielding tape to form a shielding layer, and modified resin to form a protective layer to obtain an environmentally friendly green halogen-free flame-retardant cable.

[0017] The molar ratio of pentaerythritol phosphate, pyridine, and vinyltrichlorosilane in step A1 is 1:3:4.

[0018] The molar ratio of Si-H bonds on the modified polysiloxane and the flame retardant additive in step A2 is 1:1. The amount of cassette catalyst is 0.1% of the mass of the flame retardant additive. The molar ratio of hydroxyl groups, mercaptoacetic acid, 4-dimethylaminopyridine and N,N'-dicyclohexylcarbodiimide on the functionalized additive is 1:1.5:0.2:1.5.

[0019] The weight ratio of ethylene-vinyl acetate masterbatch, modifying additive and dicumyl peroxide mentioned in step A3 is 100:10:1.2, and the model of ethylene-vinyl acetate masterbatch is 1828.

[0020] The modified polysiloxane is prepared by the following steps: Step B1: Mix DOPO and magnolol, purge nitrogen, and react for 20 h at 150 r / min and 160 °C to obtain an intermediate. Mix the intermediate, epichlorohydrin, tetrabutylammonium bromide, and dioxane, purge nitrogen, and react for 2 h at 200 r / min and 60 °C. Add sodium hydroxide aqueous solution, raise the temperature to 75 °C, and continue the reaction for 2 h to obtain the modifier. Step B2: N-allyl tert-butyl carbamate, dimethylhydrochlorosilane, caster catalyst and toluene are mixed and purged with nitrogen. Under nitrogen protection, the mixture is stirred at 200 r / min and 50 °C, and 2,6-di-tert-butylpyridine is added. The reaction is carried out for 6 h to obtain the end-capping agent. Lithium trimethylsilanolate is dissolved in tetrahydrofuran and purged with nitrogen. Under nitrogen protection, the mixture is stirred at 200 r / min and 0 °C, and tetramethylcyclotetrasiloxane and octamethylcyclotetrasiloxane are added. The mixture is heated to 25 °C and reacted for 6 h. Then the end-capping agent is added and the reaction is carried out for 1 h to obtain the pretreated polysiloxane. Step B3: Dissolve the pretreated polysiloxane in toluene, purge with nitrogen, stir and add trifluoroacetic acid at 200 r / min and 20°C, react for 1 h, cool to 0°C, add triethylamine to adjust the pH to 8, and obtain aminopolysiloxane. Mix aminopolysiloxane, modifier, triethylamine and xylene, purge with nitrogen, react at 80°C for 6 h, and obtain modified polysiloxane.

[0021] The molar ratio of DOPO and magnolol in step B1 is 2:1, and the ratio of the intermediate, epichlorohydrin, tetrabutylammonium bromide and sodium hydroxide aqueous solution is 1 mol: 2.2 mol: 0.1 mol: 200 mL, with the sodium hydroxide aqueous solution having a mass fraction of 25%.

[0022] In step B2, the molar ratio of N-allyl tert-butyl carbamate, dimethylchlorosilane, and 2,6-di-tert-butylpyridine is 1.2:1.3:0.15, the amount of cassette catalyst is 0.2% of the mass of dimethylchlorosilane, and the molar ratio of lithium trimethylsilanolate, tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, and end-capping agent is 1.5:0.5:4:1.

[0023] In step B3, the molar ratio of pretreated polysiloxane to trifluoroacetic acid is 1:5, the molar ratio of aminopolysiloxane to modifier is 1:2.2, and the amount of triethylamine used is 0.3% of the mass of the modifier.

[0024] Example 2: A method for preparing an environmentally friendly, green, halogen-free flame-retardant cable, specifically including the following steps: Step A1: Mix pentaerythritol phosphate and acetonitrile, purge with nitrogen, stir and add pyridine at 150 r / min and 25°C, heat to 55°C, add vinyltrichlorosilane, heat to 90°C, and react for 7 h to obtain flame retardant additive. Step A2: Mix modified polysiloxane, flame retardant additive, caster catalyst and toluene, purge with nitrogen, and react for 7 h at 200 r / min and 85 °C to obtain functionalized additive. Mix functionalized additive, mercaptoacetic acid, 4-dimethylaminopyridine and dichloromethane, purge with nitrogen, stir and add N,N'-dicyclohexylcarbodiimide at 150 r / min and 3 °C, raise the temperature to 25 °C and react for 22 h to obtain modified additive. Step A3: Mix ethylene-vinyl acetate masterbatch, modifying additives and dicumyl peroxide, and knead for 9 minutes at a speed of 30 r / min and a temperature of 125°C. Then, perform open mixing at a front roller temperature of 170°C and a rear roller temperature of 165°C to obtain modified resin. Twist copper wires to form a core, and then coat the core surface with modified resin to form an insulation layer, copper wire metal shielding tape to form a shielding layer, and modified resin to form a protective layer to obtain an environmentally friendly green halogen-free flame-retardant cable.

[0025] The molar ratio of pentaerythritol phosphate, pyridine, and vinyltrichlorosilane in step A1 is 1:3:4.

[0026] The molar ratio of Si-H bonds on the modified polysiloxane and the flame retardant additive in step A2 is 1:1. The amount of cassette catalyst is 0.1% of the mass of the flame retardant additive. The molar ratio of hydroxyl groups, mercaptoacetic acid, 4-dimethylaminopyridine and N,N'-dicyclohexylcarbodiimide on the functionalized additive is 1:1.5:0.2:1.5.

[0027] The weight ratio of ethylene-vinyl acetate masterbatch, modifying additive and dicumyl peroxide mentioned in step A3 is 100:10:1.2, and the model of ethylene-vinyl acetate masterbatch is 1828.

[0028] The modified polysiloxane is prepared by the following steps: Step B1: Mix DOPO and magnolol, purge nitrogen, and react for 22 hours at 150 r / min and 165 °C to obtain an intermediate. Mix the intermediate, epichlorohydrin, tetrabutylammonium bromide, and dioxane, purge nitrogen, and react for 3 hours at 200 r / min and 65 °C. Add sodium hydroxide aqueous solution, raise the temperature to 75 °C, and continue the reaction for 2 hours to obtain the modifier. Step B2: N-allyl tert-butyl carbamate, dimethylhydrochlorosilane, caster catalyst and toluene are mixed and purged with nitrogen. Under nitrogen protection, the mixture is stirred at 300 r / min and 55 °C, and 2,6-di-tert-butylpyridine is added. The reaction is carried out for 7 h to obtain the end-capping agent. Lithium trimethylsilanolate is dissolved in tetrahydrofuran and purged with nitrogen. Under nitrogen protection, the mixture is stirred at 200 r / min and 0 °C, and tetramethylcyclotetrasiloxane and octamethylcyclotetrasiloxane are added. The mixture is heated to 30 °C and reacted for 7 h. Then the end-capping agent is added and the reaction is carried out for 1.5 h to obtain the pretreated polysiloxane. Step B3: Dissolve the pretreated polysiloxane in toluene, purge with nitrogen, stir and add trifluoroacetic acid at 200 r / min and 25°C, react for 1.5 h, cool to 0°C, add triethylamine to adjust the pH to 8, and obtain aminopolysiloxane. Mix aminopolysiloxane, modifier, triethylamine and xylene, purge with nitrogen, react at 85°C for 7 h, and obtain modified polysiloxane.

[0029] The molar ratio of DOPO and magnolol in step B1 is 2:1, and the ratio of the intermediate, epichlorohydrin, tetrabutylammonium bromide and sodium hydroxide aqueous solution is 1 mol: 2.2 mol: 0.1 mol: 200 mL, with the sodium hydroxide aqueous solution having a mass fraction of 25%.

[0030] In step B2, the molar ratio of N-allyl tert-butyl carbamate, dimethylchlorosilane, and 2,6-di-tert-butylpyridine is 1.2:1.3:0.15, the amount of cassette catalyst is 0.2% of the mass of dimethylchlorosilane, and the molar ratio of lithium trimethylsilanolate, tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, and end-capping agent is 1.5:0.5:4:1.

[0031] In step B3, the molar ratio of pretreated polysiloxane to trifluoroacetic acid is 1:5, the molar ratio of aminopolysiloxane to modifier is 1:2.2, and the amount of triethylamine used is 0.3% of the mass of the modifier.

[0032] Example 3: A method for preparing an environmentally friendly, green, halogen-free flame-retardant cable, specifically including the following steps: Step A1: Mix pentaerythritol phosphate and acetonitrile, purge with nitrogen, stir and add pyridine at 200 r / min and 25°C, heat to 60°C, add vinyltrichlorosilane, heat to 90°C, and react for 8 h to obtain flame retardant additive. Step A2: Mix modified polysiloxane, flame retardant additive, caster catalyst and toluene, purge with nitrogen, and react for 8 hours at 300 r / min and 85°C to obtain functionalized additive. Mix functionalized additive, mercaptoacetic acid, 4-dimethylaminopyridine and dichloromethane, purge with nitrogen, and stir at 200 r / min and 5°C. Add N,N'-dicyclohexylcarbodiimide, heat to 30°C, and react for 24 hours to obtain modified additive. Step A3: Mix ethylene-vinyl acetate masterbatch, modifying additives and dicumyl peroxide, and knead for 10 minutes at a speed of 30 r / min and a temperature of 130°C. Then, perform open mixing at a front roller temperature of 175°C and a rear roller temperature of 165°C to obtain modified resin. Twist copper wires to form a core, and then coat the core surface with modified resin to form an insulation layer, copper wire metal shielding tape to form a shielding layer, and modified resin to form a protective layer to obtain an environmentally friendly green halogen-free flame-retardant cable.

[0033] The molar ratio of pentaerythritol phosphate, pyridine, and vinyltrichlorosilane in step A1 is 1:3:4.

[0034] The molar ratio of Si-H bonds on the modified polysiloxane and the flame retardant additive in step A2 is 1:1. The amount of cassette catalyst is 0.1% of the mass of the flame retardant additive. The molar ratio of hydroxyl groups, mercaptoacetic acid, 4-dimethylaminopyridine and N,N'-dicyclohexylcarbodiimide on the functionalized additive is 1:1.5:0.2:1.5.

[0035] The weight ratio of ethylene-vinyl acetate masterbatch, modifying additive and dicumyl peroxide mentioned in step A3 is 100:10:1.2, and the model of ethylene-vinyl acetate masterbatch is 1828.

[0036] The modified polysiloxane is prepared by the following steps: Step B1: Mix DOPO and magnolol, purge with nitrogen, and react for 24 hours at 200 r / min and 165 °C to obtain an intermediate. Mix the intermediate, epichlorohydrin, tetrabutylammonium bromide and dioxane, purge with nitrogen, and react for 3 hours at 300 r / min and 65 °C. Add sodium hydroxide aqueous solution, raise the temperature to 80 °C, and continue the reaction for 3 hours to obtain the modifier. Step B2: N-allyl tert-butyl carbamate, dimethylhydrochlorosilane, caster catalyst and toluene are mixed and purged with nitrogen. Under nitrogen protection, the mixture is stirred at 300 r / min and 60 °C, and 2,6-di-tert-butylpyridine is added. The reaction is carried out for 8 h to obtain the end-capping agent. Lithium trimethylsilanolate is dissolved in tetrahydrofuran and purged with nitrogen. Under nitrogen protection, the mixture is stirred at 300 r / min and 0 °C, and tetramethylcyclotetrasiloxane and octamethylcyclotetrasiloxane are added. The mixture is heated to 30 °C and reacted for 8 h. Then the end-capping agent is added and the reaction is carried out for 1.5 h to obtain the pretreated polysiloxane. Step B3: Dissolve the pretreated polysiloxane in toluene, purge with nitrogen, stir and add trifluoroacetic acid at 300 r / min and 25°C, react for 2 h, cool to 0°C, add triethylamine to adjust the pH to 8, and obtain aminopolysiloxane. Mix aminopolysiloxane, modifier, triethylamine and xylene, purge with nitrogen, react at 85°C for 8 h, and obtain modified polysiloxane.

[0037] The molar ratio of DOPO and magnolol in step B1 is 2:1, and the ratio of the intermediate, epichlorohydrin, tetrabutylammonium bromide and sodium hydroxide aqueous solution is 1 mol: 2.2 mol: 0.1 mol: 200 mL, with the sodium hydroxide aqueous solution having a mass fraction of 25%.

[0038] In step B2, the molar ratio of N-allyl tert-butyl carbamate, dimethylchlorosilane, and 2,6-di-tert-butylpyridine is 1.2:1.3:0.15, the amount of cassette catalyst is 0.2% of the mass of dimethylchlorosilane, and the molar ratio of lithium trimethylsilanolate, tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, and end-capping agent is 1.5:0.5:4:1.

[0039] In step B3, the molar ratio of pretreated polysiloxane to trifluoroacetic acid is 1:5, the molar ratio of aminopolysiloxane to modifier is 1:2.2, and the amount of triethylamine used is 0.3% of the mass of the modifier.

[0040] Comparative Example 1: This comparative example uses modified polysiloxane instead of the modifying additives, while the other steps are the same as in Example 1.

[0041] Comparative Example 2: This comparative example uses functionalized additives instead of modified additives, while the remaining steps are the same as in Example 1.

[0042] Comparative Example 3: This comparative example uses resorcinol diglycidyl ether instead of the modifier as in Example 1, while the other steps are the same.

[0043] The modified resins obtained in Examples 1-3 and Comparative Examples 1-3 were used to prepare 130mm×13mm×4mm samples according to the standard of GB / T2408-2021, and the vertical burning rating was tested. 150mm×10mm×4mm samples were prepared according to the standard of GB / T2406.2-2009, and the limiting oxygen index was tested. 75mm×75mm×1.6mm samples were prepared according to the standard of GB / T17651.2-1998, and the smoke transmittance was tested. The test results are shown in Table 1 below.

[0044] Table 1 As shown in Table 1, this application has a very good flame retardant and smoke suppressant effect.

[0045] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing an environmentally friendly, green, halogen-free flame-retardant cable, characterized in that: Specifically, the steps include the following: Step A1: Mix pentaerythritol phosphate and acetonitrile, purge with nitrogen for protection, stir and add pyridine, heat and add vinyltrichlorosilane to react and obtain flame retardant additive. Step A2: Mix modified polysiloxane, flame retardant additive, caster catalyst and toluene, purge with nitrogen, and react to obtain functionalized additive. Mix functionalized additive, mercaptoacetic acid, 4-dimethylaminopyridine and dichloromethane, purge with nitrogen, stir and add N,N'-dicyclohexylcarbodiimide, heat and react to obtain modified additive. Step A3: Mix ethylene-vinyl acetate masterbatch, modified additives and dicumyl peroxide, perform internal mixing and then open milling to obtain modified resin. Twist copper wires to form a core, and sequentially coat the core surface with modified resin to form an insulation layer, copper wire metal shielding tape to form a shielding layer and modified resin to form a protective layer to obtain an environmentally friendly green halogen-free flame-retardant cable.

2. The method for preparing the environmentally friendly, green, halogen-free flame-retardant cable according to claim 1, characterized in that: The molar ratio of pentaerythritol phosphate, pyridine, and vinyltrichlorosilane in step A1 is 1:3:

4.

3. The method for preparing the environmentally friendly, green, halogen-free flame-retardant cable according to claim 1, characterized in that: The molar ratio of Si-H bonds on the modified polysiloxane and the flame retardant additive in step A2 is 1:1, and the molar ratio of hydroxyl groups, mercaptoacetic acid, 4-dimethylaminopyridine and N,N'-dicyclohexylcarbodiimide on the functionalized additive is 1:1.5:0.2:1.

5.

4. The method for preparing the environmentally friendly, green, halogen-free flame-retardant cable according to claim 1, characterized in that: The weight ratio of ethylene-vinyl acetate masterbatch, modified additive and dicumyl peroxide mentioned in step A3 is 100:10:1.

2.

5. The method for preparing the environmentally friendly, green, halogen-free flame-retardant cable according to claim 1, characterized in that: The modified polysiloxane is prepared by the following steps: Step B1: Mix DOPO and magnolol, purge nitrogen gas for protection, and react to obtain an intermediate. Mix the intermediate, epichlorohydrin, tetrabutylammonium bromide and dioxane, purge nitrogen gas for protection, and react to obtain a modified agent. Add sodium hydroxide aqueous solution, heat and continue the reaction to obtain a modifier. Step B2: N-allyl tert-butyl carbamate, dimethylhydrochlorosilane, caster catalyst and toluene are mixed, nitrogen gas is introduced for protection, 2,6-di-tert-butylpyridine is added and reacted to obtain the end-capping agent. Trimethylsilyl alcohol lithium is dissolved in tetrahydrofuran, nitrogen gas is introduced for protection, tetramethylcyclotetrasiloxane and octamethylcyclotetrasiloxane are added and stirred, the reaction is heated and then the end-capping agent is added and reacted to obtain the pretreated polysiloxane. Step B3: Dissolve the pretreated polysiloxane in toluene, purge with nitrogen, stir and add trifluoroacetic acid, react, cool and add triethylamine to adjust the pH to alkaline to obtain amino polysiloxane. Mix amino polysiloxane, modifier, triethylamine and xylene, purge with nitrogen and react to obtain modified polysiloxane.

6. The method for preparing the environmentally friendly, green, halogen-free flame-retardant cable according to claim 5, characterized in that: The molar ratio of DOPO and magnolol in step B1 is 2:1, and the ratio of the intermediate, epichlorohydrin, tetrabutylammonium bromide, and sodium hydroxide aqueous solution is 1 mol: 2.2 mol: 0.1 mol: 200 mL.

7. The method for preparing the environmentally friendly, green, halogen-free flame-retardant cable according to claim 5, characterized in that: The molar ratio of N-allyl tert-butyl carbamate, dimethylhydrochlorosilane, and 2,6-di-tert-butylpyridine in step B2 is 1.2:1.3:0.15, and the molar ratio of lithium trimethylsilanolate, tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, and the end-capping agent is 1.5:0.5:4:

1.

8. The method for preparing the environmentally friendly, green, halogen-free flame-retardant cable according to claim 5, characterized in that: In step B3, the molar ratio of the pretreated polysiloxane to trifluoroacetic acid is 1:5, and the molar ratio of the aminopolysiloxane to the modifier is 1:2.

2.

9. An environmentally friendly, green, halogen-free, flame-retardant cable, characterized in that: Prepared according to any one of the preparation methods described in claims 1-8.

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