CN104311876A - Polymerization type phosphorus-containing flame retardant as well as preparation method and application thereof as epoxy resin flame retardant - Google Patents

Abstract

A polymeric phosphorus-containing flame retardant, a preparation method thereof, and an application as an epoxy resin flame retardant relate to a hydrolysis-resistant phosphorus-containing flame retardant and a preparation method thereof. The purpose of the invention is to solve the problems of low thermal stability, easy hydrolysis and difficult processing of the existing phosphorus-containing flame retardants. The general structural formula of polymeric phosphorus-containing flame retardants is: Method: using phosphoric acid or sulfuric acid as a catalyst, adding an aqueous solution of trihydroxymethyl phosphorus oxide or tetrahydroxymethyl phosphorus sulfate, a reaction solvent and a catalyst to a reaction vessel at room temperature, and then adding melamine or an amine compound at room temperature, Adjust the pH, heat up at a certain stirring speed, react at a certain temperature, then reflux reaction, cool to room temperature, then perform suction filtration, water washing and drying in sequence to obtain a white powdery solid, that is, a polymeric phosphorus-containing flame retardant . Polymeric phosphorus-containing flame retardants are added to epoxy resins as epoxy resin flame retardants.

Description

Polymeric phosphorus-containing flame retardant, preparation method thereof and application as epoxy resin flame retardant

technical field

The invention relates to a hydrolysis-resistant phosphorus-containing flame retardant, a preparation method thereof and an application as an epoxy resin flame retardant.

Background technique

Polymer materials have excellent comprehensive properties and are widely used in aerospace, electronic appliances, automobile industry and other fields, but the flammability of polymer materials and the hazards of burning and releasing toxic gases hinder their wider application. Flame retardants are a class of functional additives that can impart flame retardancy to polymer materials. Halogenated flame retardants, especially bromine-containing flame retardants, have been widely used due to their high flame retardant efficiency and low price. However, when halogenated flame retardants are thermally cracked or burned, they will generate a lot of smoke and corrosive toxic gases, such as: polybrominated dibenzofurans, dioxins, etc. Based on the requirements of environmental protection and sustainable development, some containing Halogenated flame retardants have been banned. Since the promulgation of the EU RoHS and WEEE directives in 2003, there has been an increasing call for the development of green, halogen-free and environmentally friendly flame retardants.

Organic phosphorus-containing flame retardants have the advantages of low smoke and non-toxicity during combustion, and are more environmentally friendly when used. They are recognized as one of the important products that can replace halogen-containing flame retardants and have good development prospects. At present, most organic phosphorus-containing flame retardants are liquid, such as BDP, RDP, TPP, etc., which have poor heat resistance and are easy to hydrolyze. At the same time, with the implementation of the RoHS directive, lead-free materials have become a trend, and the use temperature of lead-free soldering materials will be 30-50°C higher than that of traditional lead-containing systems, requiring materials to withstand higher processing temperatures. This requires flame retardant materials to have good thermal stability and processability, but some traditional phosphorus-based flame retardants cannot meet such requirements. When the flame retardant material is used outdoors or in a humid environment, the hydrolysis or migration of the flame retardant to the surface of the material will cause a decrease in the flame retardancy of the material and deteriorate the performance of the material. In recent years, with the rapid development of the electronics industry, people have put forward higher requirements for materials used in the electrical and electronic industries, and the requirements for green environmental protection have been further improved. Good, high thermal stability, hydrolysis resistance, non-migration and other characteristics. Therefore, there is an urgent need to research and develop phosphorus-based flame retardants with high-efficiency flame retardancy, good compatibility, high thermal stability and hydrolysis resistance to meet the high requirements for flame-retardant materials in the rapidly developing high-tech field.

Contents of the invention

The purpose of the present invention is to solve the problems of low thermal stability, easy hydrolysis and difficult processing of existing phosphorus-containing flame retardants, and provide polymeric phosphorus-containing flame retardants and their preparation methods and as epoxy resin flame retardants. application.

Polymerized phosphorus-containing flame retardant, its general structural formula is:

The preparation method of the above-mentioned polymeric phosphorus-containing flame retardant is specifically prepared according to the following steps:

Adopt water as reaction solvent, take trihydroxymethyl phosphorus oxide aqueous solution as starting material, use phosphoric acid or sulfuric acid as catalyst, add trihydroxymethyl phosphorus oxide aqueous solution, reaction solvent and catalyzer in the reaction vessel at room temperature, then in Add melamine at room temperature, then adjust the pH value to 4-6, stir evenly at a stirring speed of 300r/min-400r/min, and then at a stirring speed of 300r/min-400r/min at a heating rate of 5°C/min from Raise the temperature from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 10min-15min, and then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a temperature of 2°C/min at a temperature increase rate of 2°C/min. The reaction was continued for 2h to 3h at high temperature, and after cooling to room temperature, a white powdery solid was obtained after suction filtration, water washing and drying in sequence; the mass fraction of the trihydroxymethylphosphine oxide aqueous solution was 97%; the The mass ratio of melamine and trimethylol phosphorus oxide aqueous solution is 1:(1～1.1); the mass of described trimethylol phosphorus oxide aqueous solution and the volume ratio of water are 1g:(1～2) mL; The mass of trihydroxymethyl phosphorus oxide aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL;

The general structural formula of the polymeric phosphorus-containing flame retardant is:

Polymerized phosphorus-containing flame retardant, its general structural formula is:

The preparation method of the above-mentioned polymeric phosphorus-containing flame retardant is specifically prepared according to the following steps:

Adopt water as reaction solvent, be starting raw material with tetrakis hydroxymethyl phosphorus sulfate aqueous solution, with phosphoric acid or sulfuric acid as catalyzer, tetrakis hydroxymethyl phosphorus sulfate aqueous solution, reaction solvent and catalyzer are added in the reaction container at room temperature, then in Add melamine at room temperature, then adjust the pH value to 4~6, stir evenly at a stirring speed of 300r/min~400r/min, and then heat up at a rate of 5°C/min at a stirring speed of 300r/min~400r/min Raise the temperature from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 10min-15min, then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min, in the reaction solvent Continue to react at reflux temperature for 2h to 3h, after cooling to room temperature, then sequentially carry out suction filtration, washing and drying to obtain a white solid; the mass fraction of the tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 75%; the melamine and The mass ratio of tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 1:(1.5～1.7); The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of water are 1g:(1～1.2) mL; Described four The mass of hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL;

The general structural formula of the polymeric phosphorus-containing flame retardant is:

Polymerized phosphorus-containing flame retardant, its general structural formula is: In the general structural formula, n=2, 3, 4..., in the general structural formula, R is or and where m=2, 3, 4....

The preparation method of the above-mentioned polymeric phosphorus-containing flame retardant is specifically prepared according to the following steps:

Adopt water as reaction solvent, take trihydroxymethyl phosphorus oxide aqueous solution as starting material, use phosphoric acid or sulfuric acid as catalyst, add trihydroxymethyl phosphorus oxide aqueous solution, reaction solvent and catalyzer in the reaction vessel at room temperature, then in Add amine compounds at room temperature, then adjust the pH value to 4-6, stir evenly at a stirring speed of 300r/min-400r/min, and then increase the temperature at a rate of 5°C at a stirring speed of 300r/min-400r/min /min from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 15 minutes, then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min, in the reaction solvent Continue to react at reflux temperature for 2h-3h, after cooling to room temperature, then sequentially carry out suction filtration, water washing and drying to obtain a light yellow powder; the mass fraction of the trihydroxymethyl phosphorus oxide aqueous solution is 97%; the amine The molar ratio of compound and trihydroxymethyl phosphorus oxide aqueous solution is 3:2; The quality of described trihydroxymethyl phosphorus oxide aqueous solution and the volume ratio of water are 100g:(30～40) mL; The mass of methyl phosphorus oxide aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL; Described amine compound is ethylenediamine or urea;

The general structural formula of the polymeric phosphorus-containing flame retardant is: In the general structural formula, n=2, 3, 4....

Polymerized phosphorus-containing flame retardant, its general structural formula is: In the general structural formula, n=2, 3, 4....

The preparation method of the above-mentioned polymeric phosphorus-containing flame retardant is specifically prepared according to the following steps:

Adopt water as reaction solvent, be starting raw material with tetrakis hydroxymethyl phosphorus sulfate aqueous solution, with phosphoric acid or sulfuric acid as catalyzer, tetrakis hydroxymethyl phosphorus sulfate aqueous solution, reaction solvent and catalyzer are added in the reaction container at room temperature, then in Add amine compounds at room temperature, then adjust the pH value to 4-6, stir evenly at a stirring speed of 300r/min-400r/min, and then increase the temperature at a rate of 5°C at a stirring speed of 300r/min-400r/min /min from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 10 minutes, then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min. Continue to react at reflux temperature for 2h to 3h, after cooling to room temperature, and then sequentially carry out suction filtration, washing and drying to obtain a solid; the mass fraction of the tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 75%; the amine compound The molar ratio with tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 4:1; The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of water are 100g:(30～40) mL; The quality of phosphorus sulfate aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL; Described amine compound is ethylenediamine or urea;

The general structural formula of the polymeric phosphorus-containing flame retardant is: In the general structural formula, n=2, 3, 4....

Polymerized phosphorus-containing flame retardant, its general structural formula is: In the general structural formula, n=2, 3, 4....

The preparation method of the above-mentioned polymeric phosphorus-containing flame retardant is specifically prepared according to the following steps:

Using distilled water as the reaction solvent, tetrakis hydroxymethyl phosphorus sulfate aqueous solution as the starting material, phosphoric acid or sulfuric acid as the catalyst, piperazine, distilled water and the catalyst are added to the reaction vessel at room temperature, and the stirring speed is 300r/min～ Stir at 400r/min until completely dissolved, then use a constant pressure dropping funnel to add dropwise an aqueous solution of tetrakis hydroxymethylphosphorus sulfate with a mass fraction of 75%. React at 85°C-95°C and a stirring speed of 300r/min-400r/min for 2h, cool to room temperature, filter under reduced pressure to obtain a white solid powder, wash the white solid powder 3 times with distilled water, and then heat Under drying 2h～3h, get light yellow powder; The mass ratio of described piperazine and tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 1:(1.5～1.6); The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and The volume ratio of distilled water is 1g:(1～3)mL; The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL;

The general structural formula of the polymeric phosphorus-containing flame retardant is: In the general structural formula, n=2, 3, 4....

The application of polymeric phosphorus-containing flame retardants as epoxy resin flame retardants is added to epoxy resins as epoxy resin flame retardants and m-phenylenediamine as epoxy resin curing agents to obtain flame-retardant epoxy resin cured products , when the polymeric phosphorus-containing flame retardant is added in an amount of 10wt% to 15wt%, the flame-retardant epoxy resin cured product passes the UL-94V-0 level in the vertical burning test.

Advantages of the present invention: 1. The polymeric phosphorus-containing flame retardant prepared by the present invention contains P-C bonds in its molecular structure, heat-resistant and hydrolysis-resistant, and the product is white or light yellow powder, with a yield of more than 94% and 1% thermal weight loss decomposition The temperature is above 210°C, and the amount of char formation at 800°C is above 35% in nitrogen atmosphere. The product foams and expands when heated, and finally generates a charcoal layer with loose expansion and excellent strength. It has the advantages of strong charcoal formation and expansion ability and good thermal stability; 2. The present invention uses water as a solvent, and the reaction process is a continuous reaction. The synthesis process is simple, and the reaction time is short, usually only 3 to 4 hours, which greatly saves energy consumption, improves production efficiency, and reduces production costs; 3. Compared with the existing technology, the polymeric phosphorus-containing The flame retardant has good thermal stability and good hydrolysis resistance. After boiling the synthesized flame retardant in 100°C water for 2 hours and then filtering and drying, the mass loss of the flame retardant is only about 0.6wt%. The polymeric phosphorus-containing flame retardant prepared by the invention has good compatibility with the blended polymer substrate, is not easy to migrate, can ensure the durability of the flame retardant performance of the material, and overcomes the low thermal decomposition temperature of the small molecule phosphate flame retardant Poor compatibility with polymer matrix and easy migration. Compared with the existing polymeric phosphorus-based flame retardants, it has good swelling charcoal performance and high flame-retardant efficiency. When used in flame-retardant epoxy resins, when the addition amount of polymeric phosphorus-containing flame retardants is only When the concentration is 10-15%, the limiting oxygen index of the epoxy resin material increases from 17.8% to more than 30%, and the vertical combustion level reaches the UL-94V-0 level.

Description of drawings

The infrared spectrograms of polymeric phosphorus-containing flame retardants prepared from Fig. 1 to test seven;

Fig. 2 is the ¹³ C-NMR spectrogram of the polymeric phosphorus-containing flame retardant prepared in this test;

Figure 3 is the ³¹ P-NMR spectrum of the polymeric phosphorus-containing flame retardant prepared in this experiment.

Detailed ways

Specific implementation mode 1: This implementation mode is a polymeric phosphorus-containing flame retardant, and its general structural formula is:

Specific embodiment two: This embodiment is a preparation method of a polymeric phosphorus-containing flame retardant, specifically prepared according to the following steps:

Adopt water as reaction solvent, take trihydroxymethyl phosphorus oxide aqueous solution as starting material, use phosphoric acid or sulfuric acid as catalyst, add trihydroxymethyl phosphorus oxide aqueous solution, reaction solvent and catalyzer in the reaction vessel at room temperature, then in Add melamine at room temperature, then adjust the pH value to 4-6, stir evenly at a stirring speed of 300r/min-400r/min, and then at a stirring speed of 300r/min-400r/min at a heating rate of 5°C/min from Raise the temperature from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 10min-15min, and then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a temperature of 2°C/min at a temperature increase rate of 2°C/min. The reaction was continued for 2h to 3h at high temperature, and after cooling to room temperature, a white powdery solid was obtained after suction filtration, water washing and drying in sequence; the mass fraction of the trihydroxymethylphosphine oxide aqueous solution was 97%; the The mass ratio of melamine and trimethylol phosphorus oxide aqueous solution is 1:(1～1.1); the mass of described trimethylol phosphorus oxide aqueous solution and the volume ratio of water are 1g:(1～2) mL; The mass of trihydroxymethyl phosphorus oxide aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL;

The general structural formula of the polymeric phosphorus-containing flame retardant described in this embodiment is:

In this embodiment, the reaction system changes from white and turbid to clear and transparent during the reaction at a temperature of 85° C. to 95° C. for 10 minutes to 15 minutes, and then gradually produces white solid particles.

Specific embodiment three: This embodiment is a polymeric phosphorus-containing flame retardant, and its general structural formula is:

Specific embodiment four: This embodiment is a preparation method of a polymeric phosphorus-containing flame retardant, specifically prepared according to the following steps:

Adopt water as reaction solvent, be starting raw material with tetrakis hydroxymethyl phosphorus sulfate aqueous solution, with phosphoric acid or sulfuric acid as catalyzer, tetrakis hydroxymethyl phosphorus sulfate aqueous solution, reaction solvent and catalyzer are added in the reaction container at room temperature, then in Add melamine at room temperature, then adjust the pH value to 4~6, stir evenly at a stirring speed of 300r/min~400r/min, and then heat up at a rate of 5°C/min at a stirring speed of 300r/min~400r/min Raise the temperature from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 10min-15min, then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min, in the reaction solvent Continue to react at reflux temperature for 2h to 3h, after cooling to room temperature, then sequentially carry out suction filtration, washing and drying to obtain a white solid; the mass fraction of the tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 75%; the melamine and The mass ratio of tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 1:(1.5～1.7); The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of water are 1g:(1～1.2) mL; Described four The mass of hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL;

The general structural formula of the polymeric phosphorus-containing flame retardant described in this embodiment is:

Specific implementation mode five: This implementation mode is a polymeric phosphorus-containing flame retardant, and its general structural formula is: In the general structural formula, n=2, 3, 4..., in the general structural formula, R is or and where m=2, 3, 4....

Specific embodiment six: This embodiment is a preparation method of a polymeric phosphorus-containing flame retardant, specifically prepared according to the following steps:

Adopt water as reaction solvent, take trihydroxymethyl phosphorus oxide aqueous solution as starting material, use phosphoric acid or sulfuric acid as catalyst, add trihydroxymethyl phosphorus oxide aqueous solution, reaction solvent and catalyzer in the reaction vessel at room temperature, then in Add amine compounds at room temperature, then adjust the pH value to 4-6, stir evenly at a stirring speed of 300r/min-400r/min, and then increase the temperature at a rate of 5°C at a stirring speed of 300r/min-400r/min /min from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 15 minutes, then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min, in the reaction solvent Continue to react at reflux temperature for 2h-3h, after cooling to room temperature, then sequentially carry out suction filtration, water washing and drying to obtain a light yellow powder; the mass fraction of the trihydroxymethyl phosphorus oxide aqueous solution is 97%; the amine The molar ratio of compound and trihydroxymethyl phosphorus oxide aqueous solution is 3:2; The quality of described trihydroxymethyl phosphorus oxide aqueous solution and the volume ratio of water are 100g:(30～40) mL; The mass of methyl phosphorus oxide aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL; Described amine compound is ethylenediamine or urea;

The general structural formula of the polymeric phosphorus-containing flame retardant described in this embodiment is: In the general structural formula, n=2, 3, 4....

Specific embodiment seven: This embodiment is a polymeric phosphorus-containing flame retardant, and its general structural formula is: In the general structural formula, n=2, 3, 4....

Embodiment 8: This embodiment is a method for preparing a polymeric phosphorus-containing flame retardant, which is specifically prepared according to the following steps:

Adopt water as reaction solvent, be starting raw material with tetrakis hydroxymethyl phosphorus sulfate aqueous solution, with phosphoric acid or sulfuric acid as catalyzer, tetrakis hydroxymethyl phosphorus sulfate aqueous solution, reaction solvent and catalyzer are added in the reaction container at room temperature, then in Add amine compounds at room temperature, then adjust the pH value to 4-6, stir evenly at a stirring speed of 300r/min-400r/min, and then increase the temperature at a rate of 5°C at a stirring speed of 300r/min-400r/min /min from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 10 minutes, then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min. Continue to react at reflux temperature for 2h to 3h, after cooling to room temperature, and then sequentially carry out suction filtration, washing and drying to obtain a solid; the mass fraction of the tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 75%; the amine compound The molar ratio with tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 4:1; The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of water are 100g:(30～40) mL; The quality of phosphorus sulfate aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL; Described amine compound is ethylenediamine or urea;

The general structural formula of the polymeric phosphorus-containing flame retardant described in this embodiment is: In the general structural formula, n=2, 3, 4....

Specific embodiment nine: This embodiment is a polymeric phosphorus-containing flame retardant, and its general structural formula is: In the general structural formula, n=2, 3, 4....

Specific Embodiment Ten: This embodiment is a preparation method of a polymeric phosphorus-containing flame retardant, specifically prepared according to the following steps:

Using distilled water as the reaction solvent, tetrakis hydroxymethyl phosphorus sulfate aqueous solution as the starting material, phosphoric acid or sulfuric acid as the catalyst, piperazine, distilled water and the catalyst are added to the reaction vessel at room temperature, and the stirring speed is 300r/min～ Stir at 400r/min until completely dissolved, then use a constant pressure dropping funnel to add dropwise an aqueous solution of tetrakis hydroxymethylphosphorus sulfate with a mass fraction of 75%. React at 85°C-95°C and a stirring speed of 300r/min-400r/min for 2h, cool to room temperature, filter under reduced pressure to obtain a white solid powder, wash the white solid powder 3 times with distilled water, and then heat Under drying 2h～3h, get light yellow powder; The mass ratio of described piperazine and tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 1:(1.5～1.6); The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and The volume ratio of distilled water is 1g:(1～3)mL; The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL;

The general structural formula of the polymeric phosphorus-containing flame retardant is: In the general structural formula, n=2, 3, 4....

Specific Embodiment Eleven: This embodiment is the application of polymeric phosphorus-containing flame retardants as epoxy resin flame retardants, polymeric phosphorus-containing flame retardants as epoxy resin flame retardants and m-phenylenediamine as epoxy resins The curing agent is added to the epoxy resin to obtain a flame-retardant epoxy resin cured product. When the amount of the polymeric phosphorus-containing flame retardant reaches 10wt% to 15wt%, the flame-retardant epoxy resin cured product passes the vertical burning test of UL-94V -Level 0.

Adopt following experiment verification effect of the present invention

Test 1: The preparation method of the polymeric phosphorus-containing flame retardant is specifically prepared according to the following steps:

Adopt water as reaction solvent, take trishydroxymethyl phosphorus oxide aqueous solution as starting raw material, with phosphoric acid as catalyst, add 50.0g trihydroxymethyl phosphorus oxide aqueous solution, 100mL reaction solvent and 4mL catalyzer in the reaction vessel at room temperature, Then add 49.2g of melamine at room temperature, then adjust the pH value to 5, stir evenly at a stirring speed of 300r/min, then raise the temperature from room temperature to 92°C at a heating rate of 5°C/min at a stirring speed of 300r/min, React at a temperature of 92°C for 10 minutes, then raise the temperature from 92°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min, continue the reaction at the reflux temperature of the reaction solvent for 2 hours, cool to room temperature, and then perform suction filtration, After washing and drying, a white powdery solid is obtained; the mass fraction of the trihydroxymethyl phosphorus oxide aqueous solution is 97%;

The general structural formula of the polymeric phosphorus-containing flame retardant described in this test is:

It can be known by calculation that the yield of the polymeric phosphorus-containing flame retardant obtained in this test is 95.2%. It can be seen from the test that the initial thermal decomposition temperature of the polymeric phosphorus-containing flame retardant obtained in this test is 317°C, and the char residue at 800°C is 33.5%.

Experiment 2: Application of polymeric phosphorus-containing flame retardants as epoxy resin flame retardants, polymeric phosphorus-containing flame retardants as epoxy resin flame retardants and m-phenylenediamine as epoxy resin curing agents added to epoxy resins In the process, a flame-retardant epoxy resin cured product was obtained. When the polymeric phosphorus-containing flame retardant was added in an amount of 10 wt%, the flame-retardant epoxy resin cured product passed the UL-94V-0 level in the vertical burning test.

The polymeric phosphorus-containing flame retardant described in this test was prepared in Test 1.

The specific application process of the polymeric phosphorus-containing flame retardant described in this test is as follows:

Add polymeric phosphorus-containing flame retardant (polymeric phosphorus-containing flame retardant as epoxy resin flame retardant) to 50g epoxy resin, stir and mix evenly at 120°C, add 7.42g m-phenylenediamine (m-phenylenediamine Phenylenediamine is used as the curing agent of epoxy resin), continue to stir until m-phenylenediamine dissolves, mix well and pour into a standard mold, solidify at 150°C for 2 hours, and remove the film after cooling to room temperature to obtain a flame-retardant epoxy resin Resin cured product; the addition amount of polymeric phosphorus-containing flame retardant in the flame retardant epoxy resin cured product is 10wt%.

The flame-retardant epoxy resin cured product has passed the limiting oxygen index and vertical burning test. When the addition amount of polymeric phosphorus-containing flame retardant is 10wt%, the vertical burning test of the material can reach UL-94V-0 level, and the limiting oxygen index It reached 30.4%. Put the cured flame-retardant epoxy resin into a constant temperature 70°C water bath for 168 hours, change the water every 24 hours, take it out and dry it. The limiting oxygen index and vertical combustion test of the material are carried out. The vertical combustion test of the material is still It can pass the UL-94V-0 level, and the limiting oxygen index is slightly lowered to 29.1%.

Experiment 3: The preparation method of polymeric phosphorus-containing flame retardant, specifically prepared according to the following steps:

Adopt water as reaction solvent, take tetrakis hydroxymethyl phosphorus sulfate aqueous solution as starting raw material, take sulfuric acid as catalyzer, 50.0g tetrakis hydroxymethyl phosphorus sulfate aqueous solution, 60mL reaction solvent and 4mL catalyzer are added in the reaction vessel at room temperature, Then add 17.0g melamine at room temperature, then adjust the pH value to 5, stir evenly at a stirring speed of 300r/min, then raise the temperature from room temperature to 92°C at a heating rate of 5°C/min at a stirring speed of 300r/min , react at a temperature of 92°C for 10min, then raise the temperature from 92°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min, continue the reaction at the reflux temperature of the reaction solvent for 2h, cool to room temperature, and then carry out suction filtration in sequence , washing and drying to obtain a white solid; the mass fraction of the tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 75%;

The general structural formula of the polymeric phosphorus-containing flame retardant described in this test is: The chemical name is melamine tetramethylene phosphorus sulfate oligomer.

It can be known by calculation that the yield of the polymeric phosphorus-containing flame retardant (melamine tetramethylene phosphorus sulfate oligomer) obtained in this test is 94.15%. It can be seen from the test that the initial thermal decomposition temperature of the polymeric phosphorus-containing flame retardant obtained in this test is 313°C, and the carbon residue at 800°C reaches 43.5%.

Experiment 4: Application of polymeric phosphorus-containing flame retardants as epoxy resin flame retardants, polymeric phosphorus-containing flame retardants as epoxy resin flame retardants and m-phenylenediamine as epoxy resin curing agents added to epoxy resins In the process, a cured flame retardant epoxy resin is obtained. When the polymeric phosphorus-containing flame retardant is added in an amount of 11 to 15 wt%, the cured flame retardant epoxy resin passes the UL-94V-0 level in the vertical burning test.

The polymeric phosphorus-containing flame retardant described in this test was prepared in Test 3.

The specific application process of the polymeric phosphorus-containing flame retardant described in this test is as follows:

Add polymeric phosphorus-containing flame retardant (polymeric phosphorus-containing flame retardant as epoxy resin flame retardant) to 25g epoxy resin, stir at 120°C for 30min, add 3.18g m-phenylenediamine (m-phenylenediamine amine as the curing agent of epoxy resin), continue to stir until m-phenylenediamine dissolves, mix evenly, pour into a standard mold, cure at 150°C for 2 hours, cool naturally to room temperature, and obtain a flame-retardant epoxy resin after demoulding Cured.

Table 1 shows the relationship between the amount of polymeric phosphorus-containing flame retardant added and the properties of the cured flame-retardant epoxy resin. It can be seen from Table 1 that when the addition amount of polymeric phosphorus-containing flame retardant is only 11wt%, the oxygen index of the material is increased from 17.8% to 31.1%, and the vertical combustion level of the material has passed the UL-94V-0 level .

Put the cured flame retardant epoxy resin into a constant temperature 70°C water bath, change the water every 24 hours, and keep it for 168 hours. After taking it out, dry the sample, and test the limiting oxygen index and vertical combustion of the sample, as shown in Table 1 shown. The data in Table 1 shows that after the flame retardant epoxy resin material has passed the water resistance test, the cured product of the flame retardant epoxy resin added with 11wt% polymeric phosphorus-containing flame retardant can still pass the UL-94V-0 level, and the material’s The limiting oxygen index remains basically unchanged, indicating that the material still maintains very good flame retardancy after the water boiling test, and the flame retardant has good water resistance.

Table 1 The addition amount of polymeric phosphorus-containing flame retardant and the performance of flame-retardant epoxy resin cured product

Experiment 5: The preparation method of polymeric phosphorus-containing flame retardants is specifically prepared according to the following steps:

Water is used as the reaction solvent, with trishydroxymethyl phosphorus oxide aqueous solution as the starting raw material, phosphoric acid is used as the catalyst, 100.0g tris hydroxymethyl phosphorus oxide aqueous solution, 40mL reaction solvent and 4mL catalyst are added in the reaction vessel at room temperature, Then add 32.26g of amine compounds at room temperature, adjust the pH value to 5, stir evenly at a stirring speed of 300r/min, and then raise the temperature from room temperature to 90°C, react at a temperature of 90°C for 15 minutes, then raise the temperature from 90°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min, continue the reaction at the reflux temperature of the reaction solvent for 2 hours, cool to room temperature, and then proceed sequentially After suction filtration, water washing and drying, a light yellow powder is obtained; the mass fraction of the trihydroxymethyl phosphorus oxide aqueous solution is 97%; the amine compound is ethylenediamine;

The general structural formula of the polymeric phosphorus-containing flame retardant described in this embodiment is: In the general structural formula, n=2, 3, 4....

After calculation, it can be known that the yield of polymeric phosphorus-containing flame retardant prepared in this test is 96.26%. It can be seen from the test that the initial thermal decomposition temperature of the polymeric phosphorus-containing flame retardant prepared in this test is 212°C, and the carbon residue at 800°C is 30.4%.

Experiment 6: Application of polymeric phosphorus-containing flame retardants as epoxy resin flame retardants, polymeric phosphorus-containing flame retardants as epoxy resin flame retardants and m-phenylenediamine as epoxy resin curing agents added to epoxy resins In the process, a flame-retardant epoxy resin cured product was obtained. When the polymeric phosphorus-containing flame retardant was added in an amount of 12 wt%, the flame-retardant epoxy resin cured product passed the UL-94V-0 level in the vertical burning test.

The polymeric phosphorus-containing flame retardant described in this test was prepared in Test 5.

The specific application process of the polymeric phosphorus-containing flame retardant described in this test is as follows:

Add polymeric phosphorus-containing flame retardant (polymeric phosphorus-containing flame retardant as epoxy resin flame retardant) to 50g epoxy resin, stir at 120°C for 30min, add 7.42g m-phenylenediamine (m-phenylenediamine amine as the curing agent for epoxy resin), continue to stir until m-phenylenediamine dissolves, mix well and pour into a standard mold, keep in an oven at 105°C for 1h, then keep at 150°C for 2h, and cool to room temperature naturally After the film is removed, a flame-retardant epoxy resin cured product is obtained; the addition amount of the polymeric phosphorus-containing flame retardant in the flame-retardant epoxy resin cured product is 12 wt%.

The flame-retardant epoxy resin cured product has passed the limiting oxygen index and vertical burning test. When the addition amount of polymeric phosphorus-containing flame retardant is 12wt%, the vertical burning test of the material can reach UL-94V-0 level, and the limiting oxygen index From 17.8% to 30.1%. Put the cured flame-retardant epoxy resin into a constant temperature 70°C water bath for 168 hours, change the water every 24 hours, take it out and dry it. The limiting oxygen index and vertical combustion test of the material are carried out. The vertical combustion test of the material is still Can pass UL-94V-0 level.

Experiment 7: The preparation method of polymeric phosphorus-containing flame retardants is specifically prepared according to the following steps:

Adopt water as reaction solvent, be starting raw material with tetrakis hydroxymethyl phosphorus sulfate aqueous solution, with sulfuric acid as catalyzer, 100.00g tetrakis hydroxymethyl phosphorus sulfate aqueous solution, 30mL reaction solvent and 8mL catalyzer are added in the reaction vessel at room temperature, Then add 26.61g of amine compounds at room temperature, then adjust the pH value to 4-6, stir evenly at a stirring speed of 300r/min, and then increase the temperature from room temperature at a heating rate of 5°C/min at a stirring speed of 300r/min. Raise the temperature to 90°C, react at a temperature of 90°C for 10 minutes, then raise the temperature from 90°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min, continue the reaction at the reflux temperature of the reaction solvent for 2 hours, cool to room temperature, and then Suction filtration, water washing and drying are carried out successively to obtain a solid; the mass fraction of the tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 75%; the amine compound is urea;

The general structural formula of the polymeric phosphorus-containing flame retardant described in this embodiment is: In the general structural formula, n=2, 3, 4....

After calculation, it can be known that the yield of the polymeric phosphorus-containing flame retardant prepared in this test is 98.84%. It can be seen from the test that the initial thermal decomposition temperature of the polymeric phosphorus-containing flame retardant prepared in this test is 211.5°C, and the carbon residue at 800°C is 38.1%.

The polymeric phosphorus-containing flame retardant prepared in this test was characterized by Fourier transform infrared spectrometer, as shown in Figure 1, and the infrared spectrum of the polymeric phosphorus-containing flame retardant prepared from Figure 1 to Experiment 7; it can be seen from the figure : The broad absorption peak at 3250cm ^-1 is the stretching vibration peak of NH; the two absorption peaks at 2973cm ^-1 and 2914cm ^-1 are the stretching vibration peaks of methylene; the absorption peak at 1671cm ^-1 is the stretching vibration of C=O; 1551cm ^-1 The absorption peak at 1391cm -1 is NH bending vibration; the absorption peak at 1391cm ^-1 is CN stretching vibration; the absorption peak at 1248cm ^-1 is ^PC stretching vibration; the two absorption peaks at 1107cm ^-1 and 1043cm ^-1 are CO stretching vibration, The absorption peak is SO stretching vibration; it can be seen from the infrared spectrum that there are no two moderately strong NH symmetric and asymmetric stretching vibration special peaks of primary amides around 3400cm ^-1 and 3500cm ^-1 , indicating that primary amides Participated in the dehydration reaction. In summary, it was preliminarily determined that the target product was formed by the shrinkage reaction of some hydroxyl groups and amino groups.

Figure 2 is the ¹³ C-NMR spectrum of the polymeric phosphorus-containing flame retardant prepared in this test. It can be seen from the figure that the peak at 159.2ppm is the chemical shift of the carbonyl of the product; it appears at 32.6ppm-52.6ppm All the multiple peaks are chemical shifts of methylene (—CH ₂ —).

Figure 3 is the ³¹ P-NMR spectrum of the polymeric phosphorus-containing flame retardant prepared in this experiment. There is a strong peak at 28.4ppm in the figure, which is the chemical shift of P in the product, indicating that most of P in the product exists in this chemical environment. In addition, three small peaks appeared at 66.39ppm, -8.55ppm and -38.02ppm, because under certain conditions, a small amount of tetrakishydroxymethylphosphine oxide was converted into trihydroxymethylphosphine and trihydroxymethylphosphine during the reaction process. Substances such as methylphosphine oxide.

In summary, it is determined that the target product is generated by the shrinkage reaction between some hydroxyl groups and amino groups, and the structural formula is The chemical name is Tetrahydroxymethyl Phosphate-Ethylenediamine Oligomer.

Experiment 8: Application of polymeric phosphorus-containing flame retardant as epoxy resin flame retardant, polymeric phosphorus-containing flame retardant as epoxy resin flame retardant and m-phenylenediamine as epoxy resin curing agent added to epoxy resin In the process, a cured flame retardant epoxy resin is obtained. When the polymeric phosphorus-containing flame retardant is added in an amount of 11wt% to 15wt%, the cured flame retardant epoxy resin passes the UL-94V-0 level in the vertical burning test.

The polymeric phosphorus-containing flame retardant described in this test was prepared in Test 7.

The specific application process of the polymeric phosphorus-containing flame retardant described in this test is as follows:

Add polymeric phosphorus-containing flame retardant (polymeric phosphorus-containing flame retardant as epoxy resin flame retardant) to 50g epoxy resin, stir at 120°C for 30min, add 7.42g m-phenylenediamine (m-phenylenediamine amine as the curing agent for epoxy resin), continue to stir until m-phenylenediamine dissolves, mix well and pour into a standard mold, keep in an oven at 105°C for 1h, then keep at 150°C for 2h, and cool to room temperature naturally , to obtain a cured flame retardant epoxy resin after stripping.

Table 2 shows the relationship between the amount of polymeric phosphorus-containing flame retardant added and the properties of the cured flame-retardant epoxy resin. It can be seen from Table 2 that when the addition of flame retardant is only 12wt%, the limiting oxygen index of the material is increased from 17.8% to 28.0%, and the combustion level of the material reaches the UL-94V-0 level.

Put the flame-retardant epoxy resin cured product into a constant temperature 70°C water bath, change the water every 24 hours, and keep it for 168 hours. After taking it out, dry the sample, and test the limiting oxygen index and vertical combustion of the sample, as shown in Table 2 shown. The data in Table 2 shows that after the flame retardant epoxy resin material has passed the water resistance test, the cured flame retardant epoxy resin with 12wt% polymeric phosphorus-containing flame retardant can still pass the UL-94V-0 level, and the material’s The limiting oxygen index decreased slightly, indicating that the material still maintained very good flame retardancy after the water boiling test, and the flame retardant had good water resistance.

Table 2. The addition amount of polymeric phosphorus-containing flame retardants and the performance of flame-retardant epoxy resin cured products

Experiment 9: The preparation method of polymeric phosphorus-containing flame retardants is specifically prepared according to the following steps:

Adopt distilled water as reaction solvent, take tetrakis hydroxymethyl phosphorus sulfate aqueous solution as starting raw material, take sulfuric acid as catalyzer, at room temperature, 191.8g piperazine, 900mL distilled water and 24mL catalyzer are joined in the reaction container, and stirring speed is 300r/ Stir at 1 min until completely dissolved, then use a constant pressure dropping funnel to add dropwise 300g of tetrakishydroxymethylphosphorus sulfate aqueous solution with a mass fraction of 75%. React at a speed of 300r/min for 2h, cool to room temperature, filter under reduced pressure to obtain a white solid powder, wash the white solid powder with distilled water for 3 times, and then dry at 105°C for 2h to obtain a light yellow powder;

The general structural formula of the polymeric phosphorus-containing flame retardant is: In the general structural formula, n=2, 3, 4....

After calculation, it can be known that the yield of the polymeric phosphorus-containing flame retardant prepared in this test is 96.8%. The melting point of the polymeric phosphorus-containing flame retardant prepared by testing this test is 286.0-289.7°C. The polymeric phosphorus-containing flame retardant prepared in this test was tested by a thermogravimetric analyzer. The initial thermal decomposition temperature of the polymeric phosphorus-containing flame retardant prepared in this test was 217.5°C, and the maximum thermal decomposition rate peak appeared at 275.3°C. The carbon residue at 800°C is 22.3%.

Experiment 10: Application of polymeric phosphorus-containing flame retardant as epoxy resin flame retardant, polymeric phosphorus-containing flame retardant as epoxy resin flame retardant and m-phenylenediamine as epoxy resin curing agent added to epoxy resin In the process, a flame-retardant epoxy resin cured product was obtained. When the polymeric phosphorus-containing flame retardant was added in an amount of 11 wt%, the flame-retardant epoxy resin cured product passed the UL-94V-0 level in the vertical burning test.

The polymeric phosphorus-containing flame retardant described in this test was prepared in Test 9.

The specific application process of the polymeric phosphorus-containing flame retardant described in this test is as follows:

Add polymeric phosphorus-containing flame retardant (polymeric phosphorus-containing flame retardant as epoxy resin flame retardant) to 50g epoxy resin, stir at 120°C for 30min, add 7.42g m-phenylenediamine (m-phenylenediamine amine as the curing agent for epoxy resin), continue to stir until m-phenylenediamine dissolves, mix well and pour into a standard mold, keep in an oven at 105°C for 1h, then keep at 150°C for 2h, and cool to room temperature naturally After the film is removed, a flame-retardant epoxy resin cured product is obtained; the addition amount of the polymeric phosphorus-containing flame retardant in the flame-retardant epoxy resin cured product is 11 wt%.

The flame-retardant epoxy resin cured product has passed the limiting oxygen index and vertical burning test. When the addition amount of polymeric phosphorus-containing flame retardant is 11wt%, the vertical burning test of the material can reach UL-94V-0 level, and the limiting oxygen index From 17.8% to 30.4%. Put the cured flame-retardant epoxy resin into a constant temperature 70°C water bath for 168 hours, change the water every 24 hours, take it out and dry it. The limiting oxygen index and vertical combustion test of the material are carried out. The vertical combustion test of the material is still It can pass the UL-94V-0 level, and the limiting oxygen index of the material drops from 30.4% to 29.7%, maintaining a good flame retardant performance.

Claims (10)

1. The polymeric phosphorus-containing flame retardant is characterized in that the general structural formula of the polymeric phosphorus-containing flame retardant is: 2. the preparation method of polymeric phosphorus-containing flame retardant as claimed in claim 1 is characterized in that the preparation method of polymeric phosphorus-containing flame retardant is prepared according to the following steps: Adopt water as reaction solvent, take trihydroxymethyl phosphorus oxide aqueous solution as starting material, use phosphoric acid or sulfuric acid as catalyst, add trihydroxymethyl phosphorus oxide aqueous solution, reaction solvent and catalyzer in the reaction vessel at room temperature, then in Add melamine at room temperature, then adjust the pH value to 4-6, stir evenly at a stirring speed of 300r/min-400r/min, and then at a stirring speed of 300r/min-400r/min at a heating rate of 5°C/min from Raise the temperature from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 10min-15min, and then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a temperature of 2°C/min at a temperature increase rate of 2°C/min. The reaction was continued for 2h to 3h at high temperature, and after cooling to room temperature, a white powdery solid was obtained after suction filtration, water washing and drying in sequence; the mass fraction of the trihydroxymethylphosphine oxide aqueous solution was 97%; the The mass ratio of melamine and trimethylol phosphorus oxide aqueous solution is 1:(1～1.1); the mass of described trimethylol phosphorus oxide aqueous solution and the volume ratio of water are 1g:(1～2) mL; The mass of trihydroxymethyl phosphorus oxide aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL; The general structural formula of the polymeric phosphorus-containing flame retardant is: 3. Polymerized phosphorus-containing flame retardant, characterized in that the general structural formula of the polymerized phosphorus-containing flame retardant is: 4. the preparation method of polymeric phosphorus-containing flame retardant as claimed in claim 3 is characterized in that the preparation method of polymeric phosphorus-containing flame retardant is prepared according to the following steps: Adopt water as reaction solvent, be starting raw material with tetrakis hydroxymethyl phosphorus sulfate aqueous solution, with phosphoric acid or sulfuric acid as catalyzer, tetrakis hydroxymethyl phosphorus sulfate aqueous solution, reaction solvent and catalyzer are added in the reaction container at room temperature, then in Add melamine at room temperature, then adjust the pH value to 4~6, stir evenly at a stirring speed of 300r/min~400r/min, and then heat up at a rate of 5°C/min at a stirring speed of 300r/min~400r/min Raise the temperature from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 10min-15min, then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min, in the reaction solvent Continue to react at reflux temperature for 2h to 3h, after cooling to room temperature, then sequentially carry out suction filtration, washing and drying to obtain a white solid; the mass fraction of the tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 75%; the melamine and The mass ratio of tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 1:(1.5～1.7); The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of water are 1g:(1～1.2) mL; Described four The mass of hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL; The general structural formula of the polymeric phosphorus-containing flame retardant is: 5. The preparation method of polymeric phosphorus-containing flame retardant is characterized in that the preparation method of polymeric phosphorus-containing flame retardant is prepared according to the following steps: Adopt water as reaction solvent, take trihydroxymethyl phosphorus oxide aqueous solution as starting material, use phosphoric acid or sulfuric acid as catalyst, add trihydroxymethyl phosphorus oxide aqueous solution, reaction solvent and catalyzer in the reaction vessel at room temperature, then in Add amine compounds at room temperature, then adjust the pH value to 4-6, stir evenly at a stirring speed of 300r/min-400r/min, and then increase the temperature at a rate of 5°C at a stirring speed of 300r/min-400r/min /min from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 15 minutes, then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min, in the reaction solvent Continue to react at reflux temperature for 2h-3h, after cooling to room temperature, then sequentially carry out suction filtration, water washing and drying to obtain a light yellow powder; the mass fraction of the trihydroxymethyl phosphorus oxide aqueous solution is 97%; the amine The molar ratio of compound and trihydroxymethyl phosphorus oxide aqueous solution is 3:2; The quality of described trihydroxymethyl phosphorus oxide aqueous solution and the volume ratio of water are 100g:(30～40) mL; The mass of methyl phosphorus oxide aqueous solution and the volume ratio of catalyst are 50:(3～4)mL; Described amine compound is ethylenediamine or urea; The general structural formula of the polymeric phosphorus-containing flame retardant is: In the general structural formula, n=2, 3, 4.... 6. Polymerized phosphorus-containing flame retardant, characterized in that the general structural formula of the polymerized phosphorus-containing flame retardant is: In the general structural formula, n=2, 3, 4.... 7. the preparation method of polymeric phosphorus-containing flame retardant as claimed in claim 6 is characterized in that the preparation method of polymeric phosphorus-containing flame retardant is prepared according to the following steps: Adopt water as reaction solvent, be starting raw material with tetrakis hydroxymethyl phosphorus sulfate aqueous solution, with phosphoric acid or sulfuric acid as catalyzer, tetrakis hydroxymethyl phosphorus sulfate aqueous solution, reaction solvent and catalyzer are added in the reaction container at room temperature, then in Add amine compounds at room temperature, then adjust the pH value to 4-6, stir evenly at a stirring speed of 300r/min-400r/min, and then increase the temperature at a rate of 5°C at a stirring speed of 300r/min-400r/min /min from room temperature to 85°C-95°C, react at a temperature of 85°C-95°C for 10 minutes, then raise the temperature from 85°C-95°C to the reflux temperature of the reaction solvent at a heating rate of 2°C/min. Continue to react at reflux temperature for 2h to 3h, after cooling to room temperature, and then sequentially carry out suction filtration, washing and drying to obtain a solid; the mass fraction of the tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 75%; the amine compound The molar ratio with tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 4:1; The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of water are 100g:(30～40) mL; The quality of phosphorus sulfate aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL; Described amine compound is ethylenediamine or urea; The general structural formula of the polymeric phosphorus-containing flame retardant is: In the general structural formula, n=2, 3, 4.... 8. Polymerized phosphorus-containing flame retardant, characterized in that the general structural formula of the polymerized phosphorus-containing flame retardant is: In the general structural formula, n=2, 3, 4.... 9. the preparation method of polymeric phosphorus-containing flame retardant as claimed in claim 8, is characterized in that the preparation method of polymeric phosphorus-containing flame retardant is prepared according to the following steps: Using distilled water as the reaction solvent, tetrakis hydroxymethyl phosphorus sulfate aqueous solution as the starting material, phosphoric acid or sulfuric acid as the catalyst, piperazine, distilled water and the catalyst are added to the reaction vessel at room temperature, and the stirring speed is 300r/min～ Stir at 400r/min until completely dissolved, then use a constant pressure dropping funnel to add dropwise an aqueous solution of tetrakis hydroxymethylphosphorus sulfate with a mass fraction of 75%. React at 85°C-95°C and a stirring speed of 300r/min-400r/min for 2h, cool to room temperature, filter under reduced pressure to obtain a white solid powder, wash the white solid powder 3 times with distilled water, and then heat Under drying 2h～3h, get light yellow powder; The mass ratio of described piperazine and tetrakis hydroxymethyl phosphorus sulfate aqueous solution is 1:(1.5～1.6); The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and The volume ratio of distilled water is 1g:(1～3)mL; The quality of described tetrakis hydroxymethyl phosphorus sulfate aqueous solution and the volume ratio of catalyst are 50g:(3～4)mL; The general structural formula of the polymeric phosphorus-containing flame retardant is: In the general structural formula, n=2, 3, 4.... 10. The application of the polymeric phosphorus-containing flame retardant as claimed in claim 1, 3, 5, 6 or 8 as an epoxy resin flame retardant, characterized in that the polymeric phosphorus-containing flame retardant is used as an epoxy resin flame retardant Adding m-phenylenediamine and m-phenylenediamine as epoxy resin curing agent to epoxy resin to obtain cured flame retardant epoxy resin. The vertical burning test of the cured resin has passed the UL-94V-0 level.