CN103387673B - Fire retardant and preparation method thereof and purposes - Google Patents

Abstract

The invention discloses a flame retardant, a preparation method and application thereof. The structural formula of the flame retardant is as follows: Among them, R ₁ , R ₂ , R ₃ are C ₄ -C ₂₄ substituted aryl groups or C ₄ -C ₂₄ aryl groups whose substituents contain N, O or P, and R ₄ , R ₅ are C ₄ -C ₂₄ aryl, n is any integer from 0 to 20, and m is any integer from 2 to 100. The flame retardant is prepared from organic phosphine compound, dimethoxysilane compound, sodium iodide and diphenyl phosphate through two-step reaction. The preparation method has mild reaction conditions, simple operation and high yield. The flame retardant has good thermal stability, and has excellent flame retardant effect when applied in polymers. UL-94 reaches V-0 level, while maintaining good chemical and thermal properties.

Description

Flame retardant and its preparation method and use

technical field

The invention belongs to the field of refractory materials, and relates to a flame retardant and its preparation method and application.

Background technique

At present, the most widely used organic flame retardants in polymer materials are halogen-containing flame retardants. Although halogen-containing polymer materials have excellent flame-retardant properties and relatively low prices, they tend to release a large amount of smoke and toxic corrosive gases during combustion, which poses a threat to the environment and human life and health. Based on the requirements of environmental protection and the principle of sustainable development, some halogen-containing flame retardants have been banned. Since the promulgation of the EU ROHS and WEEE directives in 2003, the application range of halogen-containing flame retardants has been more restricted, and the development of efficient halogen-free flame retardants has become a development trend in this field.

Organophosphorus flame retardants have dual flame retardant mechanisms of gas phase and solid phase. Because of their advantages such as halogen-free, low toxicity, low smoke, plasticization, and good char formation, they have gradually attracted attention. burning effect. However, with the development and application of organophosphorus flame retardants, some problems are gradually exposed, such as some phosphorus-containing flame retardants have problems such as high volatility, easy migration, and heat resistance that need to be improved. Silicone flame retardant is a low-toxic, high-efficiency, anti-dripping, environmentally friendly flame retardant, and it is also a char-forming inhibitor. The development of phosphorous-silicon-containing organic flame retardants with good flame retardancy and thermal stability can combine the advantages of organophosphorus and organosilicon flame retardants, and play a synergistic flame retardant effect of phosphorus-silicon, which is of great significance to flame retardancy.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art, and provide a flame retardant and its preparation method and application. The flame retardant of the present invention combines the advantages of organophosphorus and organosilicon flame retardants, exerts the phosphorus-silicon synergistic flame retardant effect, has good thermal stability, and has excellent flame retardant effect when applied in polymers, UL- 94 achieves a V-0 rating while maintaining good chemical and thermal properties.

The purpose of the present invention is achieved through the following technical solutions:

In the first aspect, the present invention relates to a flame retardant, its structural formula is as shown in formula (I):

Among them, R ₁ , R ₂ , R ₃ are C ₄ -C ₂₄ substituted aryl groups or C ₄ -C ₂₄ aryl groups whose substituents contain N, O or P, and R ₄ , R ₅ are C ₄ -C ₂₄ aryl, n is any integer from 0 to 20, and m is any integer from 2 to 100. The fact that R ₄ and R ₅ are C ₄ -C ₂₄ aryl groups can improve the char-forming flame retardant effect of the flame retardant.

In a second aspect, the present invention relates to a method for preparing the above-mentioned flame retardant, comprising the steps of:

Step A, in organic solvent, organophosphine compound II Dimethoxysilane Compound III Reaction with sodium iodide to obtain intermediate IV Among them, R ₁ , R ₂ , and R ₃ are C ₄ -C ₂₄ substituted aryl groups or C ₄ -C ₂₄ aryl groups whose substituents contain N, O or P, n is any integer from 0 to 20, and X is chlorine, bromine or iodine;

Step B, in an organic solvent, the intermediate IV and phosphoric acid ester React in the presence of a Lewis base to obtain product I, the flame retardant; wherein, R ₄ and R ₅ are C ₄ -C ₂₄ aryl groups.

Preferably, in step A, the molar ratio of the organophosphine compound II, the dimethoxysilane compound III and sodium iodide is 1:(1-2):(1-2).

Preferably, in step A, the temperature of the reaction is 50-130° C., and the reaction time is 12-48 hours.

Preferably, in step B, the molar ratio of the intermediate IV to the phosphoric acid ester V is 1: (1-4).

Preferably, in step B, the Lewis base is NaOH, KOH, LiOH, K ₂ CO ₃ , KO ^t Bu, NaO ^t Bu, KOMe, NaOMe, KOEt or NaOEt.

Preferably, in step B, the reaction temperature is 20-100° C., and the reaction time is 1-10 hours.

Preferably, in steps A and B, the organic solvent is selected from tetrahydrofuran, acetone, dioxane, dichloromethane, chloroform, benzene, toluene, xylene, dimethylformamide, acetonitrile .

In a third aspect, the present invention relates to the use of the aforementioned flame retardant in the preparation of flame-retardant polymer materials.

Preferably, the flame retardant is mixed with polycarbonate to obtain a flame retardant polymer.

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

1. The flame retardant of the present invention has good thermal stability. According to differential thermal analysis, there is no obvious weight loss when heated to 300°C.

2. Adding the flame retardant of the present invention to the polymer matrix can effectively reduce the adhesion and corrosion between the polymer matrix and the corrosion-resistant container.

3. Adding the flame retardant of the present invention to the polymer matrix can effectively prevent the polymer from dripping during combustion.

4. The flame retardant of the present invention can be widely used in various thermosetting and thermoplastic materials and coatings and rubbers, and can also be widely used in plastic materials such as polyamide and polysiloxane and rubber elastomers, as well as fireproof coatings. Among various polymer materials such as polyurethane, it has a high flame retardant effect.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is the NMR spectrum of the flame retardant of the present invention; wherein a is the phosphorus spectrum, and b is the hydrogen spectrum.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those skilled in the art can make some adjustments and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

In each of the following examples, the compound II structural formula is: The structural formula of compound III is The structural formula of intermediate IV is Phosphate V has the formula

Example 1

1.1 Synthesis of intermediate IV (R ₁ =R ₂ =R ₃ =Ph; X=Cl; n=1)

Put compound II (0.1 mol), compound III (0.1 mol) and sodium iodide (0.1 mol) in a flask, add acetonitrile, stir mechanically at 90° C. for 24 hours, and cool to room temperature. The white precipitate was filtered off. The filtrate was rotary evaporated to obtain a white solid, which was washed several times with anhydrous diethyl ether, and then moved to a vacuum oven at 50° C. for 3 hours to obtain intermediate IV. Yield, 88%.

1.2 Synthesis of Flame Retardant I (R ₁ =R ₂ =R ₃ =Ph; R ₄ =R ₅ =Ph; n=1; m=4~20)

Add water (75mL) and acetone (75ml) to the flask, add NaOH 0.1moL, add intermediate IV (0.06moL) and diphenyl phosphate V (0.06moL), stir at room temperature for 4 hours, and remove the acetone by rotary evaporation. Extract with dichloromethane, wash the organic phase with saturated brine, dry over anhydrous MgSO ₄ , filter, and vacuumize, the obtained white solid is flame retardant I, and the yield is 87%. As shown in Figure 1 of the flame retardant, the phosphorus spectrum has two characteristic absorption peaks, and the chemical shift at 24.2ppm is the characteristic absorption peak on the triphenylphosphine group of the synthesized flame retardant; -10.6ppm is phosphoric acid The characteristic absorption peak of the phosphorus atom on the diphenyl ester group; in the hydrogen spectrum, the chemical shifts at 7.75-7.44ppm, 7.17-7.08ppm and 6.94-6.90ppm are the characteristic absorption peaks on the benzene ring, 1.81-1.49ppm and 0.90 -0.79ppm is the characteristic absorption peak on the methylene group, and -0.021--0.30ppm is the characteristic absorption peak on the silicon methyl group; the above analysis can determine the structure of the synthesized flame retardant, which is the structure shown in formula (I).

1.3 Application of flame retardant I in the preparation of flame retardant polymers

The flame retardant I containing 10phr, the polycarbonate of 100phr (obtaining white LGDOW Polycarbonate Ltd, its melt index is 20g/10min, density is 0.918g/cm ³ ) and anti-dripping agent ETFE1phr are mixed by Haake torque rheometer . The resulting mixture was prepared into test strips and compared to polycarbonate matrix test strips to determine the following properties:

Flame retardant:

UL-94 vertical combustion: V-0 (according to ASTMD635-77, 127mm ³ ×12.7mm ³ ×3mm ³ )

Limiting oxygen index: increased from 24.5% of polycarbonate test strip to 33% (according to ASTM D2836-97, 120mm ³ ×6.5mm ³ ×3mm ³ )

Cone calorimetry test: the peak heat release rate is reduced from 596.61kW/m ² to 485.827kW/m ² for polycarbonate substrates; the average heat release rate is reduced from 226.0kW/m ² to 202.3kW/m ² ; the fire performance index From 0.116m ² S/kW to 0.124m ² S/kW.

Thermal stability of flame retardants and their composites:

The initial decomposition temperature of the flame retardant in air is 300°C, and the carbon residue at 800°C is 19%. The initial thermal decomposition temperature of the PC/SiPP composite with the addition of 10 phr of the flame retardant reaches 400 °C, and its thermal weight loss behavior is similar to that of pure PC, indicating that the addition of the flame retardant will not reduce the thermal stability of the material. sex.

It can be seen from the above data that the phosphorus-containing silicon flame retardant prepared in this example has good flame retardancy and thermal stability. In practical application, the use of very low content of this product can make the product achieve high flame retardant effect, and at the same time meet the processing temperature requirements of most plastics, so as to meet their use requirements.

Comparative example 1

Synthesis of Intermediate IV (R ₁ =R ₂ =R ₃ =Ph; X=Cl; n=1)

Put compound II (0.1 mol), compound III (0.1 mol) and sodium iodide (0.1 mol) in a flask, add acetonitrile, stir mechanically at 90° C. for 24 hours, and cool to room temperature. The white precipitate was filtered off. The filtrate was rotary evaporated to obtain a white solid, which was washed several times with anhydrous diethyl ether, and then moved to a vacuum oven at 50° C. for 3 hours to obtain intermediate IV. Yield, 88%.

Synthesis of Intermediate VI (R ₁ =R ₂ =R ₃ =Ph; n=1)

Put intermediate IV (0.15 mol) and potassium ethyl xanthate (0.15 mol) in a flask, add chloroform, stir mechanically at 40° C. for 24 hours, and cool to room temperature. The white precipitate was filtered off. The filtrate was rotary evaporated to obtain a light yellow solid, which was moved to a vacuum oven at 50 ° C for 3 hours to obtain intermediate VI Yield 85%.

Synthesis of Flame Retardant I (R ₁ =R ₂ =R ₃ =Ph; R ₄ =R ₅ =H; n=1; m=4~20)

The intermediate VI was placed in a flask, after adding acetonitrile, phosphoric acid (0.1 mol) was added dropwise, mechanically stirred at 90° C. for 12 hours, and cooled to room temperature. The filtrate was rotary evaporated to obtain a light yellow solid, which was transferred to a vacuum oven at 50° C. for 3 hours to obtain flame retardant I with a yield of 86%.

The application of the flame retardant of this comparative example in the preparation of flame retardant polymers is the same as in Example 1; the performance test results are as follows:

The flame retardant I containing 10phr, the anti-dripping agent ETFE of 1phr, the polycarbonate of 100phr (obtained from LGDOW Polycarbonate Ltd, its melt index is 20g/10min, density is 0.918g/cm ³ ) by Haake torque rheology instrument mix. The resulting mixture was prepared into test strips and compared to polycarbonate matrix test strips to determine the following properties:

Flame retardant:

UL-94 vertical combustion: V-0 (according to ASTMD635-77, 127mm ³ ×12.7mm ³ ×3mm ³ )

Limiting oxygen index: increased from 24.5% of polycarbonate test strips to 30.9% (according to ASTMD2836-97, 120mm ³ ×6.5mm ³ ×3mm ³ )

Thermal stability of flame retardants and their composites:

The initial decomposition temperature of the flame retardant in air is 300°C, and the carbon residue at 800°C is 13%. The initial thermal decomposition temperature of PC/SiPP composites with 10 phr of flame retardant can reach 400℃, and its thermal weight loss behavior is similar to that of pure PC.

By comparing Example 1 with Example 1, it is found that by changing the structure of R4 and R5 groups, the amount of char residue can be increased from 13% to 19%, thereby enhancing the char formation effect. Its oxygen index test shows that its flame retardant effect has indeed been improved, from 30.9% to 33%.

Comparative example 2

Synthesis of Intermediate IV (R ₁ =R ₂ =R ₃ =C ₆ H ₁₃ ; X=Cl; n=1)

Put compound II (0.1 mol), compound III (0.1 mol) and sodium iodide (0.1 mol) in a flask, add acetonitrile, stir mechanically at 90° C. for 24 hours, and cool to room temperature. The white precipitate was filtered off. The filtrate was rotary evaporated to obtain a white solid, which was washed several times with anhydrous diethyl ether, and then moved to a vacuum oven at 50° C. for 3 hours to obtain intermediate IV. Yield, 88%.

Synthesis of Flame Retardant I (R ₁ =R ₂ =R ₃ =C ₆ H ₁₃ ; R ₄ =R ₅ =Ph; n=1; m=4~20)

Add water (75mL) and acetone (75ml) to the flask, add NaOH 0.1moL, add intermediate IV (0.06moL) and diphenyl phosphate V (0.06moL), stir at 35°C for 4 hours, spin the solution to remove acetone , extracted with dichloromethane, washed the organic phase with saturated brine, dried over anhydrous MgSO ₄ , filtered, and vacuumized to obtain a white solid that was flame retardant I with a yield of 87%.

The application of the flame retardant of this comparative example in the preparation of flame retardant polymers is the same as in Example 1; the performance test results are as follows:

Flame retardant:

UL-94 vertical combustion: V-0 (according to ASTMD635-77, 127mm ³ ×12.7mm ³ ×3mm ³ )

Limiting oxygen index: increased from 24.5% of polycarbonate test strips to 27.8% (according to ASTMD2836-97, 120mm ³ ×6.5mm ³ ×3mm ³ )

Thermal stability of flame retardants and their composites:

The initial decomposition temperature of the flame retardant in air is 300°C, and the carbon residue at 800°C is 11%. The initial thermal decomposition temperature of PC/SiPP composites with 10phr added flame retardant reached 390℃.

Comparative example 3

Synthesis of intermediate IV (R ₁ = R ₂ = R ₃ = phenyl group containing S in the substituent; X = Cl; n = 1)

Put compound II (0.1 mol), compound III (0.1 mol) and sodium iodide (0.1 mol) in a flask, add acetonitrile, stir mechanically at 90° C. for 24 hours, and cool to room temperature. The white precipitate was filtered off. The filtrate was rotary evaporated to obtain a white solid, which was washed several times with anhydrous diethyl ether, and then moved to a vacuum oven at 50° C. for 3 hours to obtain intermediate IV. Yield, 88%.

Synthesis of Flame Retardant I (R ₁ = R ₂ = R ₃ = phenyl group containing S in the substituent; R ₄ = R ₅ = Ph; n = 1; m = 4~20)

Add water (75mL) and acetone (75ml) to the flask, add NaOH 0.1moL, add intermediate IV (0.06moL) and diphenyl phosphate V (0.06moL), stir at 35°C for 4 hours, spin the solution to remove acetone , extracted with dichloromethane, washed the organic phase with saturated brine, dried over anhydrous MgSO ₄ , filtered, and vacuumized to obtain a white solid that was flame retardant I with a yield of 87%.

The application of the flame retardant of this comparative example in the preparation of flame retardant polymers is the same as in Example 1; the performance test results are as follows:

Flame retardant:

UL-94 vertical combustion: V-0 (according to ASTMD635-77, 127mm ³ ×12.7mm ³ ×3mm ³ )

Limiting oxygen index: increased from 24.5% of polycarbonate test strip to 32.5% (according to ASTMD2836-97, 120mm ³ ×6.5mm ³ ×3mm ³ )

Thermal stability of flame retardants and their composites:

The initial decomposition temperature of the flame retardant in air is 300°C, and the carbon residue at 800°C is 12%. The initial thermal decomposition temperature of PC/SiPP composites with flame retardant addition of 10phr reaches 380℃.

Example 2

2.1 Synthesis of Intermediate IV (R ₁ =R ₂ =R ₃ =N-containing phenyl in the substituent; X=Cl; n=1)

Put compound II (0.1 mol), compound III (0.1 mol) and sodium iodide (0.1 mol) in a flask, add acetonitrile, stir mechanically at 90° C. for 24 hours, and cool to room temperature. The white precipitate was filtered off. The filtrate was rotary evaporated to obtain a white solid, which was washed several times with anhydrous diethyl ether, and then moved to a vacuum oven at 50° C. for 3 hours to obtain intermediate IV. Yield, 88%.

2.2 Synthesis of Flame Retardant I (R ₁ = R ₂ = R ₃ = N-containing phenyl in the substituent; R ₄ = R ₅ = Ph; n = 1; m = 4~20)

Add water (75mL) and acetone (75ml) to the flask, add NaOH 0.1moL, add intermediate IV (0.06moL) and diphenyl phosphate V (0.06moL), stir at 35°C for 4 hours, spin the solution to remove acetone , extracted with dichloromethane, washed the organic phase with saturated brine, dried over anhydrous MgSO ₄ , filtered, and vacuumized to obtain a white solid that was flame retardant I with a yield of 87%.

2.3 Application of flame retardant I in the preparation of flame retardant polymers

With 10 phr of flame retardant I, 100 phr of polycarbonate (obtained from LGDOW Polycarbonate Ltd with a melt index of 20 g/10 min and a density of 0.918 g/cm ³ ) was mixed by Haake torque rheometer. The resulting mixture was prepared into test strips and compared to polycarbonate matrix test strips to determine the following properties:

Flame retardant:

UL-94 vertical combustion: V-0 (according to ASTMD635-77, 127mm ³ ×12.7mm ³ ×3mm ³ )

Limiting oxygen index: increased from 24.5% of polycarbonate test strip to 33.2% (according to ASTMD2836-97, 120mm ³ ×6.5mm ³ ×3mm ³ )

Thermal stability of flame retardants and their composites:

The initial decomposition temperature of the flame retardant in air is 300°C, and the carbon residue at 800°C is 18%. The initial thermal decomposition temperature of PC/SiPP composites with 10phr added flame retardant reaches 400℃.

Example 3

3.1 Synthesis of intermediate IV (R ₁ =R ₂ =C ₄ aryl, R ₃ =C ₂₄ aryl; X=Br; n=0)

Put compound II (0.1 mol), compound III (0.2 mol) and sodium iodide (0.2 mol) in a flask, add chloroform, stir mechanically at 50° C. for 48 hours, and cool to room temperature. The white precipitate was filtered off. The filtrate was rotary evaporated to obtain a white solid, which was washed several times with anhydrous diethyl ether, and then moved to a vacuum oven at 50° C. for 3 hours to obtain intermediate IV. Yield, 88%.

3.2 Synthesis of flame retardant I (R ₁ =R ₂ =C ₄ aryl, R ₃ =C ₂₄ aryl; R ₄ =C ₁₀ aryl, R ₅ =Ph; n=0; m=2 ~5)

Add water (75mL) and acetonitrile (75ml) into the flask, add K ₂ CO ₃ 0.1moL, add intermediate IV (0.06moL) and diphenyl phosphate V (0.24moL), stir at 100°C for 1 hour, spin the solution Acetone was evaporated, extracted with dichloromethane, the organic phase was washed with saturated brine, dried over anhydrous MgSO ₄ , filtered, and vacuumized to obtain a white solid which was flame retardant I with a yield of 87%.

3.3 Application of flame retardant I in the preparation of flame retardant polymers

With 10 phr of flame retardant I, 100 phr of polycarbonate (obtained from LGDOW Polycarbonate Ltd with a melt index of 20 g/10 min and a density of 0.918 g/cm ³ ) was mixed by Haake torque rheometer. The resulting mixture was prepared into test strips and compared to polycarbonate matrix test strips to determine the following properties:

Flame retardant:

UL-94 vertical combustion: V-0 (according to ASTMD635-77, 127mm ³ ×12.7mm ³ ×3mm ³ )

Limiting oxygen index: increased from 24.5% of polycarbonate test strips to 32.8% (according to ASTMD2836-97, 120mm ³ ×6.5mm ³ ×3mm ³ )

Thermal stability of flame retardants and their composites:

The initial decomposition temperature of the flame retardant in air is 300°C, and the carbon residue at 800°C is 19.5%. The initial thermal decomposition temperature of PC/SiPP composites with 10phr added flame retardant reaches 400℃.

Example 4

4.1 Synthesis of intermediate IV (R ₁ =C ₂₀ aryl group, R ₂ =C ₈ aryl group, R ₃ =C ₅ aryl group whose substituent contains O; X=I; n=20)

Put compound II (0.1 mol), compound III (0.15 mol) and sodium iodide (0.2 mol) in a flask, add dioxane, stir mechanically at 130° C. for 12 hours, and cool to room temperature. The white precipitate was filtered off. The filtrate was rotary evaporated to obtain a white solid, which was washed several times with anhydrous diethyl ether, and then moved to a vacuum oven at 50° C. for 3 hours to obtain intermediate IV. Yield, 88%.

4.2 Synthesis of flame retardant I (R ₁ =C ₂₀ aryl group, R ₂ =C ₈ aryl group, R ₃ =C ₅ aryl group containing O in the substituent; R ₄ =C ₅ aryl group, R ₅ = C ₅ aryl; n = 20; m = 90 ~ 100)

Add water (75mL) and tetrahydrofuran (75ml) to the flask, add NaOMe0.1moL, add intermediate IV (0.06moL) and diphenyl phosphate V (0.12moL), stir at 30°C for 10 hours, spin the solution to remove acetone , extracted with dichloromethane, washed the organic phase with saturated brine, dried over anhydrous MgSO ₄ , filtered, and vacuumized to obtain a white solid that was flame retardant I with a yield of 87%.

4.3 Application of Flame Retardant I in Preparation of Flame Retardant Polymers

With 10 phr of flame retardant I, 100 phr of polycarbonate (obtained from LGDOW Polycarbonate Ltd with a melt index of 20 g/10 min and a density of 0.918 g/cm ³ ) was mixed by Haake torque rheometer. The resulting mixture was prepared into test strips and compared to polycarbonate matrix test strips to determine the following properties:

Flame retardant:

UL-94 vertical combustion: V-0 (according to ASTMD635-77, 127mm ³ ×12.7mm ³ ×3mm ³ )

Limiting oxygen index: increased from 24.5% of polycarbonate test strip to 33.7% (according to ASTMD2836-97, 120mm ³ ×6.5mm ³ ×3mm ³ )

Thermal stability of flame retardants and their composites:

The initial decomposition temperature of the flame retardant in air is 300°C, and the carbon residue at 800°C is 18.5%. The initial thermal decomposition temperature of PC/SiPP composites with 10phr added flame retardant reaches 400℃.

Example 5

5.1 Synthesis of intermediate IV (R ₁ = C ₄ substituted aryl group containing P in the substituent, R ₂ = R ₃ = Ph; X = Cl; n = 8)

Put compound II (0.1 mol), compound III (0.15 mol) and sodium iodide (0.15 mol) in a flask, add dimethylformamide, stir mechanically at 90° C. for 24 hours, and cool to room temperature. The white precipitate was filtered off. The filtrate was rotary evaporated to obtain a white solid, which was washed several times with anhydrous diethyl ether, and then moved to a vacuum oven at 50° C. for 3 hours to obtain intermediate IV. Yield, 88%.

5.2 Synthesis of Flame Retardant I (R ₁ = C ₄ substituted aryl group containing P in the substituent, R ₂ = R ₃ = Ph; R ₄ = R ₅ = Ph; n = 8; m = 50~80)

Add water (75mL) and acetone (75ml) to the flask, add NaO ^t Bu 0.1moL, add intermediate IV (0.06moL) and diphenyl phosphate V (0.18moL), stir at 60°C for 6 hours, and rotate the solution to evaporate Remove acetone, extract with dichloromethane, wash the organic phase with saturated brine, dry over anhydrous MgSO ₄ , filter, and vacuumize to obtain a white solid that is flame retardant I with a yield of 87%.

5.3 Application of Flame Retardant I in Preparation of Flame Retardant Polymers

With 10 phr of flame retardant I, 100 phr of polycarbonate (obtained from LGDOW Polycarbonate Ltd with a melt index of 20 g/10 min and a density of 0.918 g/cm ³ ) was mixed by Haake torque rheometer. The resulting mixture was prepared into test strips and compared to polycarbonate matrix test strips to determine the following properties:

Flame retardant:

UL-94 vertical combustion: V-0 (according to ASTMD635-77, 127mm ³ ×12.7mm ³ ×3mm ³ )

Limiting oxygen index: increased from 24.5% of polycarbonate test strip to 33.9% (according to ASTMD2836-97, 120mm ³ ×6.5mm ³ ×3mm ³ )

Thermal stability of flame retardants and their composites:

The initial decomposition temperature of the flame retardant in air is 300°C, and the carbon residue at 800°C is 19.2%. The initial thermal decomposition temperature of PC/SiPP composites with 10phr added flame retardant reaches 400℃.

In summary, the preparation method of the flame retardant of the present invention has mild reaction conditions, is easy to operate, and has a high yield; the prepared flame retardant has good thermal stability, and has an excellent flame retardant effect when applied to polymers. UL-94 achieves a V-0 rating while maintaining good chemical and thermal properties.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims (10)

1. a fire retardant, its structural formula is such as formula shown in (I):

wherein, R ₁, R ₂, R ₃for substituting group is containing the C of N, O or P ₄~ C ₂₄substituted aryl or C ₄~ C ₂₄aryl, R ₄, R ₅for C ₄~ C ₂₄aryl, n is arbitrary integer in 0 ~ 20, and m is arbitrary integer in 2 ~ 100.

2. a preparation method for fire retardant as claimed in claim 1, is characterized in that, comprises the steps:

Steps A, in organic solvent, organic phosphine compound II dimethoxysilane compound III with sodium iodide reaction, obtain intermediate compound IV wherein, R ₁, R ₂, R ₃for substituting group is containing the C of N, O or P ₄~ C ₂₄substituted aryl or C ₄~ C ₂₄aryl, n is arbitrary integer in 0 ~ 20, and X is chlorine, bromine or iodine;

Step B, in organic solvent, described intermediate compound IV and phosphoric acid ester V under Lewis base exists, reaction, obtains product I, i.e. described fire retardant; Wherein, R ₄, R ₅for C ₄~ C ₂₄aryl.

3. the preparation method of fire retardant as claimed in claim 2, it is characterized in that, in steps A, the mol ratio of described organic phosphine compound II, dimethoxysilane compound III and sodium iodide is 1: (1 ~ 2): (1 ~ 2).

4. the preparation method of fire retardant as claimed in claim 2, it is characterized in that, in steps A, the temperature of described reaction is 50 ~ 130 DEG C, and the time is 12 ~ 48 hours.

5. the preparation method of fire retardant as claimed in claim 2, it is characterized in that, in step B, the mol ratio of described intermediate compound IV and phosphoric acid ester V is 1: (1 ~ 4).

6. the preparation method of fire retardant as claimed in claim 2, it is characterized in that, in step B, described Lewis base is NaOH, KOH, LiOH, K ₂cO ₃, KO ^tbu, NaO ^tbu, KOMe, NaOMe, KOEt or NaOEt.

7. the preparation method of fire retardant as claimed in claim 2, it is characterized in that, in step B, the temperature of described reaction is 20 ~ 100 DEG C, and the reaction times is 1 ~ 10 hour.

8. the preparation method of fire retardant as claimed in claim 2, it is characterized in that, in steps A and B, described organic solvent is all selected from the one in tetrahydrofuran (THF), acetone, dioxan, methylene dichloride, trichloromethane, benzene,toluene,xylene, dimethyl formamide, acetonitrile.

9. the purposes in flame-proofed polymer material prepared by a fire retardant as claimed in claim 1.

10. fire retardant as claimed in claim 9 is preparing the purposes in flame-proofed polymer material, it is characterized in that, by described fire retardant and polycarbonate mixing, obtains flame-retardant polymer.